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In this paper, a visual navigation method based on binocular vision and a deep learning approach is proposed to solve the navigation problem of the unmanned aerial vehicle autonomous aerial refueling docking process. First, to meet the requirements of high accuracy and high frame rate in aerial refueling tasks, this paper proposes a single-stage lightweight drogue detection model, which greatly increases the inference speed of binocular images by introducing image alignment and depth-separable convolution and improves the feature extraction capability and scale adaptation performance of the model by using an efficient attention mechanism (ECA) and adaptive spatial feature fusion method (ASFF). Second, this paper proposes a novel method for estimating the pose of the drogue by spatial geometric modeling using optical markers, and further improves the accuracy and robustness of the algorithm by using visual reprojection. Moreover, this paper constructs a visual navigation vision simulation and semi-physical simulation experiments for the autonomous aerial refueling task, and the experimental results show the following: (1) the proposed drogue detection model has high accuracy and real-time performance, with a mean average precision (mAP) of 98.23% and a detection speed of 41.11 FPS in the embedded module; (2) the position estimation error of the proposed visual navigation algorithm is less than ±0.1 m, and the attitude estimation error of the pitch and yaw angle is less than ±0.5°; and (3) through comparison experiments with the existing advanced methods, the positioning accuracy of this method is improved by 1.18% compared with the current advanced methods.

The smart unmanned vending machine using machine vision technology suffers from the sharp decrease of detection accuracy due to the incomplete image collection of items by monocular camera in complex environment, and the lack of obvious features in dense stacking of items. In this paper, a binocular camera system is designed to effectively solve the problems of distortion and coverage caused by monocular camera. Besides, an image-stitching algorithm is developed to splice the images captured by the camera, which reliefs the burden of computation for back-end recognition processing brought by the binocular camera. A new model YOLOv3-TinyE is proposed based on YOLOv3-tiny model. Based on the data set of 21, 000 images captured in real scenarios that containing 20 different type of beverages, the comparison experimental results show that YOLOv3-TinyE model achieves the mean average precision of 99.15%, and the inference speed is 2.91 times faster than that of YOLOv3 model, and the detection accuracy of YOLOv3-TinyE model based on binocular vision is higher than that based on monocular vision. The results suggest that the designed method achieves the goal in terms of inference speed and average precision, that is, it is able to satisfy the requirements for real-world applications.

In this paper, a kinematic separation calibration method of 6R series manipulator is proposed, and its absolute accuracy is improved by a binocular camera and standard sphere. First, a geometric error mapping model for the robotic arm was established, and the error parameters were divided into position parameters and attitude parameters for calibration purposes. Second, in the process of solving error parameters using numerical algorithms, it is easy to encounter matrix ill-conditioned problems. The spectral correction iteration method is introduced to improve the calculation accuracy. Third, three standard balls are installed at the end of the robotic arm as markers, and the center coordinates are measured using a binocular camera to obtain the actual end pose parameters. To verify the effectiveness of the proposed method, a simulation model verification was designed, and the results showed that the separation calibration method was the best. Finally, the IRB-1200 robot was successfully calibrated using the proposed method; the average robot position and angle error after calibration was significantly decreased. The position accuracy was improved by 66.9%, and the attitude accuracy was improved by 86.2%.

The cleaning and maintenance of large-scale façades is a high-risk industry. Although existing wall-climbing robots can replace humans who work on façade surfaces, it is difficult for them to operate on façade protrusions due to a lack of perception of the surrounding environment. To address this problem, this paper proposes a binocular vision-based method to assist wall-climbing robots in performing autonomous rust removal and painting. The method recognizes façade protrusions through binocular vision, compares the recognition results with an established dimension database to obtain accurate information on the protrusions and then obtains parameters from the process database to guide the operation. Finally, the robot inspects the operation results and dynamically adjusts the process parameters according to the finished results, realizing closed-loop feedback for intelligent operation. The experimental results show that the You Only Look Once version 5 (YOLOv5) recognition algorithm achieves a 99.63% accuracy for façade protrusion recognition and a 93.33% accuracy for the detection of the rust removal effect using the histogram comparison method. The absolute error of the canny edge detection algorithm is less than 3 mm and the average relative error is less than 2%. This paper establishes a vision-based façade operation process with good inspection effect, which provides an effective vision solution for the automation operation of wall-climbing robots on the façade.

In order to solve the problem of autonomous deviation control of roadheader in complex roadway environment, the paper analyzes the deviation reasons of roadheader, defines the functional requirements of deviation correction control of roadheader, proposes a deviation correction control system of coal mine roadheader based on digital twin, and introduces the system composition. Taking the roadheader central position control as an example, the system deviation correction control mechanism is analyzed, and a deviation correction control method of the roadheader based on binocular vision image information is proposed. Taking the roadway image detected by binocular vision as the basic data, by extracting the characteristics of the roadway image and analyzing the relationship between the roadway coordinate system and the roadheader coordinate system, the position and attitude parameters of the roadheader relative to the roadway space are calculated, and the deviation correction control of the roadheader is carried out according to the solution results. The digital model and the positioning and orientation parameter database of the roadheader and the roadway are constructed, and the virtual remote deviation correction control of the roadheader is realized through the virtual-real mapping relationship. The experimental results show that the deviation correction control system based on digital twin can compensate the yaw angle and offset distance of the roadheader under different working conditions effectively. The deviation correction process can be displayed on the monitoring interface in real time, and the simulation results of deviation correction path planning are consistent with the actual working conditions.

Although most jurisdictions allow stereoscopically deficient and monocular individuals to drive, studies regarding these visual components' effects on driving have to date yielded contradicting results. Interviews, record reviews, and experiments have been used to unmask these effects. In interviews, participants with amblyopia reported several difficulties operating automobiles. Record reviews yielded mixed results, with studies revealing an increased crash rate and/or severity in a group of stereoscopically deficient commercial drivers, whereas studies of non-commercial drivers failed to make that association. Furthermore, experimental studies showed that individuals with reduced stereopsis braked earlier and were less likely to crash. With regard to monocularity, real-life experiments failed to demonstrate a poorer driving performance and simulation studies showed that drivers with sudden monocularity were more likely to crash and drive off the road. [ J Pediatr Ophthalmol Strabismus . 2022;59(1):6–12.]

Monitoring plant growth is essential in modern agriculture to guarantee productivity. Since manual measurement of plant characteristics is laborious and expensive, automatic measures are desirable. This can be accomplished by methods such as vision-based structure from motion (SFM) to obtain the 3-D information of a plant. An SFM method based on binocular vision is here developed to acquire the physical parameters of plants. In this method, image sequences are captured by a binocular camera from multiple views of the target plant to improve the effectiveness and simplify the implementation. The spatial relationships between adjacent images are estimated through image feature extraction and matching. A disparity map is then built and the 3-D coordinate of each image pixel is obtained by applying stereo-vision. The connected coordinates then constitute the 3-D model of the plant. By doing so, plant structure parameters, such as height, canopy size, and trunk diameter, can be derived from the 3-D model. Experimental results show that the measured plant height, the canopy width, and the trunk diameter of the target plant are within an acceptable accuracy at the millimeter level, and the mean errors of the measured sizes are all less than 2%. This demonstrates the potential value of the proposed method for online growth monitoring of agricultural plants.

Crack width is the main manifestation of concrete material deterioration. To measure the crack information quickly and conveniently, a non-contact measurement method of concrete planar structure crack based on binocular vision is proposed. Firstly, an improved DeeplabV3+ semantic segmentation model is proposed, which uses L-MobileNetV2 as the backbone feature extraction network, adopts IDAM structure to extract high-level semantic information, introduces ECA attention mechanism, and optimizes the loss function of the model to achieve high-precision segmentation of crack areas. Secondly, the plane space coordinate equation of the concrete structure was constructed based on the principle of binocular vision and SIFT feature point matching, and the crack width was calculated by combining the segmented image. Finally, to verify the performance of the above method, a measurement test platform was built. The experimental results show that the RMSE of the crack measurement by using the algorithm is less than 0.2 mm, and the error rate is less than 4%, which has stable accuracy in different measurement angles. It solves the problem of fast and convenient measurement of the crack width of concrete planar structures in an outdoor environment.

In order to improve the accuracy of multi-projection correction fusion, a multi-projection correction method based on binocular vision is proposed. To date, most of the existing methods are based on the single-camera mode, which may lose the depth information of the display wall and may not accurately obtain the details of the geometric structure of the display wall. The proposed method uses the depth information of a binocular camera to build a high-precision 3D display wall model; thus, there is no need to know the specific CAD size of the display wall in advance. Meanwhile, this method can be applied to display walls of any shape. By calibrating the binocular vision camera, the radial and eccentric aberration of the camera can be reduced. The projector projects the encoded structured light stripes, and the high-precision 3D structural information of the projection screen can be reconstructed according to the phase relationship after collecting the deformation stripes on the projection screen with the binocular camera. Thus, the screen-projector sub-pixel-level mapping relationship is established, and a high-precision geometric correction is achieved. In addition, by means of the one-to-one mapping relation between the phase information and the three-dimensional space points, accurate point cloud matching among multiple binocular phase sets could be established, so that such method can be applied to any quantity of projectors. The experimental results based on various special-shaped projection screens show that, comparing to the single-camera-based method, the proposed method improves the geometric correction accuracy of multi-projection stitching by more than 20%. This method also has many advantages, such as strong universality, high measurement accuracy, and rapid measurement speed, which indicate its wide application potential in many different fields.

Aquest estudi es centra en un grup de nens/es de 8 i 9 anys de diferents escoles de Terrassa on se’ls realitza un seguit de proves optomètriques al Centre Universitari de la Visió. S’estudia si els valors del test DEM s’ajusten als valors de normalitat estipulats per cada edat i s’analitza quina tipologia DEM presenten. Un any després es torna a avaluar el DEM i s’estudia si hi ha hagut una evolució en aquests resultats. Els principals resultats obtinguts són què hi ha una millora en el resultat del DEM entre la primera i la segona visita de la cohort. També s’arriba a la conclusió que existeix associació entre el tipus d’escola i els resultats del test DEM. En les escoles de baixa complexitat els resultats tendeixen a ser més positius que en les d’alta complexitat. Per últim, es defineix que una gran majoria de nens/es s’ajusten als valors de normalitat per cada grup d’edat i a mesura que van avançant de curs, més elevat es el nombre de nens/es que es troben dins d’aquests valors de normalitat del test DEM. Este estudio se centra en un grupo de niños/as de 8 y 9 años de diferentes escuelas de Terrassa donde se les realiza unas pruebas optométricas en el Centro Universitario de la Visión. Se estudia si los valores del test DEM se ajustan a los valores de normalidad estipulados para cada edad y se analiza que tipología DEM presentan. Un año después se vuelve a evaluar el DEM y se estudia si ha habido una evolución en estos resultados Los principales resultados obtenidos son que hay una mejora en el resultado del DEM entre la primera y la segunda visita de la cohorte. También se llega a la conclusión de que existe una asociación entre el tipo de escuela y los resultados del test DEM. En las escuelas de baja complejidad los resultados tienden a ser más positivos que en las de alta complejidad. Por último, se define que una gran mayoría de niños/as se ajustan a los valores de normalidad para cada grupo de edad y a medida que van avanzando de curso, más elevado es el número de niños/as que se encuentran dentro de estos valores de normalidad del test DEM. This study focuses on a group of 8 and 9-year-old children from different schools in Terrassa who undergo optometric tests at Centre Universitari de la Visió. It is studied if the values ​​of the DEM test adjust to the normality values ​​stipulated for each age and it is analyzed what type of DEM they present. One year later, the DEM is re-evaluated and studied if there has been an evolution in these results. The main results obtained are that there is an improvement in the DEM result between the first and second visits of the cohort. It is also concluded that there is an association between the type of school and the results of the DEM test. In schools of low complexity the results tend to be more positive than in those of high complexity. Finally, it is defined that a large majority of children adjust to the normal values ​​for each age group and as they grow up, the higher is the number of children who are within the values ​​of normality of the DEM test.

Problemstellung: Die vorliegende Bachelorarbeit beschäftigt sich mit kurz- und langfristigen Auswirkungen von Alkoholkonsum auf das visuelle und okulomotorische System aus orthoptischer Sicht. Es wird eine Übersicht über alkohol-induzierte Beeinträchtigungen verschiedener Bereiche des visuellen und okulomotorischen Systems dargeboten, darunter die Sehschärfe, das Binokularsehen, die zentrale Okulomotorik, die Kontrastwahrnehmung sowie das Gesichtsfeld. Methode: Als methodische Vorgehensweise zur Beantwortung der Forschungsfrage wird eine systematische Literaturrecherche durchgeführt. Im Zuge dieser wird in diversen Datenbanken und Bibliotheken nach Fachbüchern, Fachzeitschriften und Studien zum Thema Alkoholkonsum im Zusammenhang mit visuellen und okulomotorischen Symptomen und Störungen recherchiert. Ergebnisse: Hinsichtlich der Sehschärfe wird eine durch Alkoholkonsum ausgelöste Herabsetzung der retinalen Abbildungsqualität sowie eine Beeinträchtigung des visuellen Unterscheidungsvermögens beschrieben. Zusätzlich kann Alkoholkonsum das Risiko diverser Augenerkrankungen, durch welche die Sehschärfe reduziert wird, fördern. Die Minderung der Qualität des Binokularsehens zeigt sich in Form einer Reduktion des Stereosehens und der horizontalen Fusionsbreite. Zudem kommt es durch Alkoholeinfluss zu Winkelveränderungen bei horizontalen Heterophorien. Alkohol-induzierte Störungen der zentralen Okulomotorik äußern sich als Auftreten eines allseitigen Blickrichtungsnystagmus, als Sakkadierung der langsamen Folgebewegungen sowie als Beeinträchtigung der Fixationssuppression des vestibulo-okulären Reflexes. Es kann zu einem positionellen Alkoholnystagmus kommen. Übermäßiger Alkoholkonsum erhöht das Risiko, an einer Wernicke-Enzephalopathie zu erkranken, die mit Störungen der zentralen Okulomotorik einhergeht. Durch Alkoholkonsum ausgelöste Einschränkungen der Kontrastwahrnehmung zeigen sich als Minderung der Kontrastsensitivität für verschiedene Ortsfrequenzen. Das Gesichtsfeld kann nach Alkoholkonsum konzentrische Einschränkungen aufweisen. Diskussion: Es gelten Limitationen der vorliegenden Bachelorarbeit sowie der verwendeten Literatur zu berücksichtigen. In Studien werden gegensätzliche Auswirkungen von Alkohol auf unterschiedliche Augenerkrankungen, welche die Sehschärfe mindern können, beschrieben. Einige Autor*innen legen alkohol-induzierte Störungen der zentralen Okulomotorik dar, ohne konkrete Aussagen über die dazu führende Trinkmenge oder Trinkfrequenz zu tätigen. Allgemein muss berücksichtigt werden, dass einige Aspekte des visuellen und okulomotorischen Systems bislang noch nicht ganzheitlich erforscht sind. Objective: This bachelor thesis deals with short- and long-term effects of alcohol consumption on the visual and oculomotor system from an orthoptic point of view. A review of alcohol-induced impairments of different areas of the visual and oculomotor system is presented, including visual acuity, binocular vision, central oculomotor function, contrast perception, and visual field. Methods: As a methodological approach to answer the research question, a systematic literature review is conducted. In the course of this, various databases and libraries are used to find reference books, journals and studies on the topic of alcohol consumption in connection with visual and oculomotor symptoms and disorders. Results: Regarding the visual acuity, a reduction in retinal image quality triggered by alcohol consumption and an impairment of visual discrimination are described. In addition, alcohol consumption may promote the risk of various ocular diseases by which visual acuity is reduced. The reduction in the quality of binocular vision is manifested in the form of a reduction in stereo vision and horizontal fusion width. In addition, alcohol influence causes angular changes in horizontal heterophoria. Alcohol-induced disturbances of central oculomotor function manifest as the occurrence of an all-sided gaze direction nystagmus, saccadic slow following movements, and impaired fixation suppression of the vestibulo-ocular reflex. Positional alcohol nystagmus may occur. Excessive alcohol consumption increases the risk of developing Wernicke's encephalopathy, which is associated with central oculomotor dysfunction. Impairments in contrast perception triggered by alcohol consumption manifest as a reduction in contrast sensitivity to different spatial frequencies. The visual field may show concentric limitations after alcohol consumption. Discussion: Limitations of the bachelor thesis as well as of the used literature must be considered. Studies describe opposite effects of alcohol on different eye diseases, which can reduce visual acuity. Some authors describe alcohol-induced disturbances of central oculomotor function without making concrete statements about the amount or frequency of drinking leading to these disturbances. In general, it must be considered that some aspects of the visual and oculomotor system have not yet been researched holistically.

Objective: The present study aimed to assess the immediate and short-term effect of cervical spinal manipulation (SM), compared with placebo, on the magnitude of near and distance exophoria, in adults with asymptomatic exophoria. Methods: In this single-blinded randomized controlled trial, individuals with a clinical diagnosis of horizontal exophoria, as confirmed with the prism alternating cover test (PACT), were allocated to a single intervention session using a high-velocity low-amplitude cervical SM technique or sham placebo (manual contact under the head). The study outcome was the magnitude of horizontal heterophoria, as a measure of binocular vision efficiency, at near (40 cm) or distance (4 meters) fixation, using the PACT. Evaluations were made at baseline, immediately after intervention, and at a 1-week follow-up. Results: From May to September 2021, forty-four volunteers (23 females), with a mean age of 35 (9.5) years, were recruited and equally distributed into the study groups. All participants completed follow-up assessments, and no adverse events were reported. There was a significant time*group interaction for exophoria at near vision but not at distance fixation. The SM group showed a significant decrease of near exophoria, compared to the control group, at the 1-week follow-up (mean difference -1.09 prism diopters, 95% CI, -0.20 to -1.98 prism diopters). Conclusion: The use of cervical SM therapy resulted in a significant reduction of the magnitude of horizontal exophoria at near vision (medium effect size), compared with placebo, in asymptomatic young adults. However, these effects were not observed at distance fixation and should be considered with caution due to the pre-post design with a single intervention session and the short-term follow-up. Impact: The present findings suggest short-term benefits of SM therapy to manage undiagnosed ocular convergence disorders, although changes were not clinically relevant.

Objective: This study aimed to assess the immediate and short-term effects of cervical spinal manipulation, compared with a placebo, on the magnitude of near and distance exophoria in adults with asymptomatic exophoria. Methods: In this single-blind, randomized controlled trial, individuals with a clinical diagnosis of horizontal exophoria confirmed with the prism alternating cover test (PACT) were allocated to a single intervention session using a high-velocity, low-amplitude cervical spinal manipulation technique or a sham intervention (manual contact under the head). Outcomes were the magnitude of horizontal heterophoria, as a measure of binocular vision efficiency at near (40 cm) or distance (4 m) fixation, using the PACT. Evaluations were made at baseline, immediately after intervention, and at a 1-week follow-up. Results: From May to September 2021, 44 volunteers (23 women), with a mean age of 35 (SD = 9.5) years, were recruited and equally distributed into the study groups. All participants completed follow-up assessments, and no adverse events were reported. There was a significant time x group interaction for exophoria at near vision, but not at distance fixation. The spinal manipulation group showed a significant decrease of near exophoria compared to the control group at the 1-week follow-up (mean difference = -1.09 prism diopters; 95% CI = -0.20 to - 1.98 prism diopters). Conclusion: The use of cervical spinal manipulation therapy resulted in a significant reduction of the magnitude of horizontal exophoria at near vision (medium effect size), compared with the placebo, in young adults who are asymptomatic. However, these effects were not observed at distance fixation and should be considered cautiously due to the pre-post design with a single intervention session and the short-term follow-up. Impact: The findings suggest short-term benefits of spinal manipulation therapy can manage undiagnosed ocular convergence disorders, although changes were not clinically relevant.

Background: The aim of this study is to evaluate the long-term outcomes of primary and secondary intraocular lens (IOL) implantation following removal of congenital/developmental cataracts. Methods: One hundred and forty-four patients aged under 16 years who were followed up between 2003 and 2021 were analyzed retrospectively. The long-term results of children who underwent surgery before 2 years of age for congenital or developmental cataracts and underwent secondary IOL implantation after 2 years of age and those who underwent cataract surgery with primary IOL implantation after 2 years of age were compared. Patients with traumatic, secondary cataracts and cataracts due to ocular anomalies were not included in the study. Results: We evaluated 64 patients (mean age 9.5 ± 4.5 years) with secondary IOL implantation and 80 patients (mean age 12.8 ± 4.1 years) with primary IOL implantation in the study. Distance and near best-corrected visual acuities were significantly better in the primary IOL group than the secondary IOL group (p < 0.001). Incidence of strabismus after primary IOL surgery was significantly lower and presence of binocular vision was more often than the secondary IOL group (p = 0.002). There was no significant difference between the two groups in terms of refraction and myopic shift (p = 0.242, p = 0.172, respectively). Mean refractive changes were significant in unilateral cases of secondary IOL group and primary IOL group (p = 0.013, p = 0.049, respectively) and myopic shift was also greater in both groups of unilateral cases than the fellow eyes (p = 0.023, p = 0.012, respectively). Discussion: Visual outcomes and binocular vision were better, and the incidence of strabismus was also much less in the primary IOL group.

Purpose. To analyze changes in binocular vision functions in patients with acutely acquired esotropia after preoperative correction by prisms. Material and methods. The study included 16 patients with acutely acquired esotropia with diplopia. Depending on the tactics of preoperative case management, two groups were distinguished. Eight patients with acutely acquired esotropia of the Bielshowsky type at the age from 12 to 35 years old (mean age, M±sd – 17.5±1.9 years). This group underwent preoperative prismatic correction of diplopia and the deviation angle, as well as eight patients with acutely acquired esotropia of the Bielshowsky type at the age from 12 to 35 years (18.5±1.9 years). Patients in this group underwent surgery without prior prismatic correction. Fresnel prisms were used to select and assign prismatic correction. The patien s were monitored dynamically. Results. In the course of treatment 1 group (prismatic correction followed by surgical correction) according to the indicator of Worth’s four-dot test color test, revealed a statistically significant increase in the frequency of value of the binocular single vision (p=0.041), the frequency of the presence of stereovision according to the Fly-test (p=0.013), fusion amplitude in the distance by 1.11 times (p=0.033) and near fusion amplitude by 1.15 times (p=0.003). Significant differences between the groups were observed only in the frequency of stereovision presence according to the Fly-test after treatment, which was 2.0 times higher in group 1 (p=0.041). Conclusion. Prismatic correction in combination with surgical treatment had better curative benefits than surgery itself in improving both binocular and stereoscopic visual functions.

To evaluate binocular visual function after unilateral and bilateral implantation of segmented refractive multifocal intraocular lenses (MIOLs). This prospective comparative pilot study included patients who underwent SBL-3 (Lenstec; + 3.00 D) implantation at Peking University Third Hospital. Patients were divided into two groups (monocular or binocular surgery). Thirty-two patients with emmetropic presbyopic contralateral eyes and 49 patients with bilateral SBL-3 implantation within a week between eyes were included in the unilateral SBL-3 and bilateral groups, respectively. At 3-month follow-up, the main outcomes were binocular uncorrected distant, intermediate, and near visual acuity (UDVA, UIVA, and UNVA). Secondary outcomes included binocular best-corrected visual acuity at all distances, defocus curve, contrast sensitivity, photic phenomena, spectacle independence, patient satisfaction, and National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) score. The essential perceptual phenomena constituting binocular vision, simultaneous perception, fusion, and stereopsis were also evaluated. Both groups showed similar binocular UDVA and UIVA, but UNVA was significantly better in the bilateral group (0.07 ± 0.07 versus 0.12 ± 0.07, P = 0.008). Better binocular defocus curve at intermediate to near focal points, higher percentage of spectacle independence at near distance, and NEI-VFQ-25 near activity scores were observed in the bilateral group. No significant differences in contrast sensitivity, photic phenomena, overall satisfaction, other NEI-VFQ-25 subscales, fusional amplitude, and stereoacuity were found between groups. Unilateral implantation of segmented refractive MIOL provided desirable distant visual acuity and high patient satisfaction, but inferior intermediate and near visual outcomes compared with bilateral implantation.

Purpose: Involvement of the accommodative mechanism in myopia progression has been hypothesised and investigated over the past years, given the emerging myopia crisis across the globe. This review aimed at exploring the clinical role of accommodative function in myopia development.Methods: A literature search of MEDLINE and EMBASE was performed from conception to May 2021.Results:The initial stimulus for accommodation is derived from near work, in an attempt of the eye to obtain a clear image. When there is a lag in the accommodative response, the resulting blurred retinal image is believed to precipitate axial elongation and lead to myopia development. The dynamic accommodative functions implicated in binocular vision evaluation include the accommodative accuracy, amplitude and facility. Association of these accommodative parameters to current treatment options for myopia control is of great clinical interest. Effective myopia treatments, including orthokeratology, multifocal lenses and atropine eyedrops appear to induce changes in the dynamic accommodative response.Conclusions: Current knowledge indicates an evident relationship between the accommodative mechanism and myopia development. Further investigation by future studies is warranted in order to explore the use of accommodative function as a promising myopia-monitoring tool.

In order to improve the accuracy of automatic obstacle recognition algorithm for driverless vehicles, an automatic obstacle recognition algorithm for driverless vehicles based on binocular vision is constructed. Firstly, the relevant parameters of the camera are calibrated around the new car coordinate system to determine the corresponding obstacle position of the vehicle. At the same time, the three-dimensional coordinates of obstacle points are obtained by binocular matching method. Then, the left and right cameras are used to capture the feature points of obstacles in the image to realize the recognition of obstacles. Finally, the experimental results show that for obstacle 1, the recognition error of the algorithm is 0.03 m; for obstacle 2, the recognition error is 0.02 m; for obstacle 3, the recognition error is 0.01 m. The algorithm has small recognition error. The vehicle coordinate system is added in the camera calibration process, which can accurately measure the relative position information between the vehicle and the obstacle.

Journal of comparative physiology (2021). doi:10.1007/s00359-021-01524-z, Published by Springer, Berlin ; Heidelberg [u.a.]

To identify normative near point of convergence (NPC) data for healthy high-school-aged athletes (13-19 years old) and determine the percentage of individuals with NPC scores that fall outside the currently accepted clinical cutoff value of 5 cm. Another objective was to determine the relationship between sex, concussion history, and attention deficit disorder/attention deficit hyperactivity disorder (ADD/ADHD) with NPC scores, if any.Case series.High-school sports medicine clinic.Near point of convergence was assessed in 718 high-school student athletes (141 females and 577 males) with an average age of 15.96 ± 1.16 years.None.An accommodation convergence ruler was used to measure NPC. Near point of convergence scores were repeated a total of 3 times and the mean used for all statistical analyses.The NPC scores for all participants averaged 3.58 cm, and the intraclass correlation coefficient for the 3 repeated measurements was 0.956. Approximately 20% of mean NPC scores were above the accepted upper limit of 5 cm. Although a statistically significant effect for sex was identified, the difference between them was considered clinically insignificant. No relationship between NPC and history of concussion or ADD/ADHD was identified.Results indicate that in high-school-aged subjects, approximately 20% of individuals may have NPC values that fall outside the current critical cutoff value and may lead to incorrect diagnosis of ocular dysfunction. In addition, NPC does not seem to be affected by the history of concussion or a diagnosis of ADD/ADHD.

The appearance-based method for gaze estimation has great potential to work well under various conditions, but current learning-based methods ignore inferior eye images in datasets caused by poor eye region locating, occlusions and abnormal head poses. These images badly impact the accuracy of estimation. In the study, inspired by binocular vision characteristics, we propose two cooperative sub-networks, True Gaze Consistency Network (TG-Net) and Single Gaze Inconsistency Network(SG-Net) which composes TSG-Net. TG-Net and SG-Net cooperate through a residual paradigm and Informing module. More specially, TG-Net explicitly extracts the consistency of paired eyes and weights high-level features from two paired-eye images utilizing SE-Block and an artificial gaze direction, named True Gaze. SG-Net outputs residual momentums based on True Gaze for better estimation of paired eyes. Experimental results on three benchmark datasets demonstrate that the proposed method performs competitively against the existed representative CNN-Based methods. TSG-Net improves on the state-of-the-art by 22% on MPIIGaze and shows more advantages in additional analysis.

Amblyopia or lazy eye is a dysfunction of the visual system that appears during childhood and traditionally has been considered untreatable in adults. Its main consequences are the loss of visual acuity and contrast sensitivity of the amblyopic eye and binocular vision impairments. During the last years videogames have been used as a therapeutic tool for amblyopia with the inconclusive results. The present work has assessed the effectiveness of a virtual reality videogame (AmbliOK®) in the neurorehabilitation of four adult clinical cases with anisometropic amblyopia. Visual acuity, contrast sensitivity, stereopsis and interocular suppression were assessed before, during, immediately after, one month and one year (in one patient) after the training. The intervention was conducted along four weeks (10 h) and yielded the variable results. In general, all patients showed an improvement in visual functions although not all ameliorated in the same way. Visual acuity measures improved in all patients, falling outside the amblyopia criterion at the end of the treatment. However, the improvement was not maintained one month later in two patients. Contrast sensitivity progressively improved for the amblyopic and the fellow eyes with all patients showing better results one month after the treatment. The patient assessed one year after still showed better results than in the baseline. Patients showing bad stereopsis in the baseline reached a performance considered normal one month and even one year after the treatment. The effectiveness of the treatment seems to be related to the characteristics of patients.

Purpose: To compare the stereoacuity between patients with anisometropic amblyopia who were treated and achieved normal visual acuity (VA) and normal children and evaluate the factors associated with stereoacuity.Methods: We retrospectively reviewed the records of 37 pediatric patients with anisometropic amblyopia who recovered to normal VA with glasses and occlusion treatment (amblyopia group) and 34 normal children (control group). The Worth 4-dot test, Lang II test, Titmus test, and TNO test were performed to measure stereoacuity. Clinical characteristics were compared between the two groups, and factors affecting stereoacuity outcomes were also analyzed in the amblyopic group.Results: The mean age at diagnosis of amblyopia was 5.3 ± 1.4 years, and the mean VAs at diagnosis were 0.41 ± 0.24 and 0.06 ± 0.07 in amblyopic and fellow eyes, respectively. The mean duration of occlusion was 19.00 ± 9.44 months, and VA of amblyopic eyes improved to 0.04 ± 0.04 after occlusion treatment. The patient characteristics did not differ significantly between the two groups, except for the final VA of the amblyopic eye. The final mean logarithm of minimal angle of resolution VA of the amblyopic eye in the amblyopia group was significantly worse than that in the control group. The number of patients with normal stereoacuity was significantly lower in the amblyopia group than in the control group on Lang II, Titmus, and TNO tests. Factors associated with poor stereoacuity were severe amblyopia in the Lang II test and poor post-treatment VA of the amblyopic eye in the Titmus test.Conclusions: Stereoacuity was worse in the amblyopia group than in the control group, despite normal visual development. The depth of amblyopia and post-treatment VA were associated with stereoacuity outcomes. Thus, VA improvement should be closely monitored in the amblyopic eye to obtain good stereoacuity.

Purpose To evaluate and compare different surgical approaches for the treatment of Helveston syndrome and provide further information for preoperative planning. Methods From February 2008 to December 2018, data of 52 patients with Helveston syndrome were retrospectively reviewed. Different surgical approaches were selected based on the extent of A-pattern exotropia, dissociated vertical deviation (DVD), and both superior oblique muscle overaction (SOOA) with fundus photograph intorsion. Eye position, A-pattern, DVD, superior oblique muscle function, and binocular vision function were evaluated pre- and postoperatively. The average follow-up duration was 20.5 months. Results Nine cases underwent simultaneous horizontal deviation correction with bilateral superior rectus recession, 24 underwent simultaneous horizontal deviation correction with bilateral superior oblique muscle lengthening, and 19 underwent two stages of horizontal deviation correction with superior oblique muscle lengthening, and later bilateral superior rectus recession. A-pattern, DVD, SOOA, and fundus intorsion were all collapsed in all patients postoperatively. Forty-five patients had an orthophoric eye position with considerably aligned ocular movements postoperatively. The total success rate was 86.5%. Postoperatively, eight of the 10 patients with diplopia experienced a recovery of binocular single vision and three had a recovery of rudimentary stereopsis (Titmus 3000–400 s of arc). The compensatory head posture of patients improved significantly postoperatively. Conclusions The surgical planning of Helveston syndrome should be designed based on the degree of the A-pattern, SOOA, DVD, and the intorsion in fundus photographs, and the appropriate approach should be selected to improve patient satisfaction.

Brain-specific loss of a microtubule-binding protein collapsin response mediator protein-2 (CRMP2) in the mouse recapitulates many schizophrenia-like behaviors of human patients, possibly resulting from associated developmental deficits in neuronal differentiation, path-finding, and synapse formation. However, it is still unclear how the Crmp2 loss affects neuronal circuit function and plasticity. By conducting in vivo and ex vivo electrophysiological recording in the mouse primary visual cortex (V1), we reveal that CRMP2 exerts a key regulation on the timing of postnatal critical period (CP) for experience-dependent circuit plasticity of sensory cortex. In the developing V1, the Crmp2 deficiency induces not only a delayed maturation of visual tuning functions but also a precocious CP for visual input-induced ocular dominance plasticity and its induction activity – coincident binocular inputs right after eye-opening. Mechanistically, the Crmp2 deficiency accelerates the maturation process of cortical inhibitory transmission and subsequently promotes an early emergence of balanced excitatory-inhibitory cortical circuits during the postnatal development. Moreover, the precocious CP plasticity results in deteriorated binocular depth perception in adulthood. Thus, these findings suggest that the Crmp2 deficiency dysregulates the timing of CP for experience-dependent refinement of circuit connections and further leads to impaired sensory perception in later life.

PURPOSE To evaluate clinical outcomes delivered by a new hybrid presbyopia-correcting intraocular lens (IOL): TECNIS Synergy ZFR00V IOL model (Johnson & Johnson Vision). SETTING Hospital da Luz Lisboa, Lisbon, Portugal. DESIGN Prospective observational study. METHODS Patients undergoing bilateral IOL implantation were included. Visual acuity (VA) was measured for far distance, intermediate (66 cm), and near (40 cm) vision under both photopic and mesopic conditions. In addition, at the 3-month follow-up visit, the defocus curve was obtained for binocular vision, and questionnaires were administered to measure spectacle independence and level of satisfaction ( quality of vision and Catquest-SF9) with the surgical outcomes. RESULTS 54 eyes of 27 patients were included. At the 3-month follow-up, under photopic conditions, VA values were as follows: corrected distance VA (CDVA) = -0.02 ± 0.07, distance-corrected intermediate VA = 0.03 ± 0.11, and distance-corrected near VA (DCNVA) = 0.00 ± 0.08, whereas under mesopic conditions, VA values were as follows: CDVA = -0.01 ± 0.05 and DCNVA = 0.07 ± 0.09. The binocular defocus curve revealed that mean VA was better than 0.30 logMAR within the +1.00 to -4.00 diopters (D) interval, and better than 0.10 logMAR between +0.50 and -3.00 D. All patients achieved distance vision spectacle freedom, whereas 3.7% of them said they used them in certain intermediate or near vision situations. As much as 88% of the patients reported being fairly satisfied or very satisfied. CONCLUSIONS The TECNIS Synergy ZFR00V IOL model used for cataract surgery is capable of restoring visual function while providing very good intermediate and near vision, under both photopic and mesopic conditions, resulting in a high level of patient satisfaction.

To improve the positioning accuracy of mobile robot, a visual SLAM algorithm based on binocular vision and inertial navigation is presented. In the front part of visual SLAM, a semi-direct binocular visual odometer combining direct method with characteristic method is presented to maintain the fast calculation speed and high accuracy of direct method. In the back-end optimization stage, the visual data and IMU data are fused together, and error functions are constructed in a sliding window in a non-linear optimization way to optimize the accuracy of pose calculation. The algorithm proposed in this paper is validated in EuRoc dataset. The results show that the positioning accuracy of the SLAM system OKVIS, ROVIO and VINS-Mono is significantly improved in both Machine Hall and Vicon Room scenarios, while maintaining high operational efficiency, compared with the open source visual inertial navigation fusion SLAM system OKVIS, ROVIO and VINS-Mono.

If robot uses 2D lidar or binocular camera to locate obstacles, there will be some problems such as missing obstacle information or inaccurate obstacle locating, which will affect the normal work of the robot. In order to obtain accurate 3D obstacle information, this paper proposes an algorithm for fusing 2D lidar and binocular vision to complete the obstacle location. In this paper, the depth value of the 2D lidar point cloud is used as a benchmark. By fitting the error equation of the binocular camera point cloud depth value, the depth value of the camera point cloud is modified to obtain an accurate 3D camera point cloud, thereby obtaining an accurate 3D obstacle information. Many experiments have proved that the fusion algorithm of 2D lidar and binocular vision can obtain accurate 3D obstacle information. The method of fusion 2D lidar and binocular vision can approximately achieve the measurement effect of 3D lidar, and the point cloud of obstacles is relatively dense, so the accurate 3D obstacle information can be obtained. This method can reduce the influence of single sensor on the robot locating obstacles, thus completing the accurate locating of obstacles, which is of certain significance to robot navigation.

Binocular disparity provides critical information about three-dimensional (3D) structures to support perception and action. In the past decade significant progress has been made in uncovering human brain areas engaged in the processing of binocular disparity signals. Yet, the fine-scale brain processing underlying 3D perception remains unknown. Here, we use ultra-high-field (7T) functional imaging at submillimeter resolution to examine fine-scale BOLD fMRI signals involved in 3D perception. In particular, we sought to interrogate the local circuitry involved in disparity processing by sampling fMRI responses at different positions relative to the cortical surface (i.e., across cortical depths corresponding to layers). We tested for representations related to 3D perception by presenting participants (male and female, N = 8) with stimuli that enable stable stereoscopic perception [i.e., correlated random dot stereograms (RDS)] versus those that do not (i.e., anticorrelated RDS). Using multivoxel pattern analysis (MVPA), we demonstrate cortical depth-specific representations in areas V3A and V7 as indicated by stronger pattern responses for correlated than for anticorrelated stimuli in upper rather than deeper layers. Examining informational connectivity, we find higher feedforward layer-to-layer connectivity for correlated than anticorrelated stimuli between V3A and V7. Further, we observe disparity-specific feedback from V3A to V1 and from V7 to V3A. Our findings provide evidence for the role of V3A as a key nexus for disparity processing, which is implicated in feedforward and feedback signals related to the perceptual estimation of 3D structures. SIGNIFICANCE STATEMENT Binocular vision plays a significant role in supporting our interactions with the surrounding environment. The fine-scale neural mechanisms that underlie the brain9s skill in extracting 3D structures from binocular signals are poorly understood. Here, we capitalize on recent advances in ultra-high-field functional imaging to interrogate human brain circuits involved in 3D perception at submillimeter resolution. We provide evidence for the role of area V3A as a key nexus for disparity processing, which is implicated in feedforward and feedback signals related to the perceptual estimation of 3D structures from binocular signals. These fine-scale measurements help bridge the gap between animal neurophysiology and human fMRI studies investigating cross-scale circuits, from micro circuits to global brain networks for 3D perception.

Background: Consecutive esotropia (ET) is persistent esodeviation for 24 weeks afterward bilateral lateral rectus recession (BLRR) for correcting exotropia (XT) with or without diplopia. Some patients may have limited eye movement; amblyopia and loss of binocularity can result. Early postoperative overcorrection has been recommended in surgical treatment of intermittent XT due to tendency towards postoperative exotropic drift. ET with small angles (within 15 PD) vanishes naturally over time, whereas bigger angles are more likely to be present at the start. Patients who have ET that has persisted for at least 24 weeks after BLRR and has been present for more than 15 postoperative days should have surgery. Objective: Hallmark the updated lines of management of consecutive esotropia. Conclusion: For the purpose of maintaining one MR muscle for a future intervention, several research have shown that ET can be performed consecutively after BLR recession by advancement of LR muscle previously recessed and MR muscle recession in the more deviating eye. Studies in recent years have sought to determine the effectiveness of the use of lateral rectus advancement in the treatment of consecutive ET.

Coordination between visual and motor processes is critical for the selection of stable footholds when walking in uneven terrains. While recent work (Matthis et al. in Curr Biol 8(28):1224–1233, 2018) demonstrates a tight link between gaze (visual) and gait (motor), it remains unclear which aspects of visual information play a role in this visuomotor control loop, and how the loss of this information affects that relationship. Here we examine the role of binocular information in the visuomotor control of walking over complex terrain. We recorded eye and body movements while normally-sighted participants walked over terrains of varying difficulty, with intact vision or with vision in one eye blurred to disrupt binocular vision. Gaze strategy was highly sensitive to the complexity of the terrain, with more fixations dedicated to foothold selection as the terrain became more difficult. The primary effect of increased sensory uncertainty due to disrupted binocular vision was a small bias in gaze towards closer footholds, indicating greater pressure on the visuomotor control process. Participants with binocular vision losses due to developmental disorders (i.e., amblyopia, strabismus), who have had the opportunity to develop alternative strategies, also biased their gaze towards closer footholds. Across all participants, we observed a relationship between an individual’s typical level of binocular visual function and the degree to which gaze is shifted toward the body. Thus the gaze–gait relationship is sensitive to the level of sensory uncertainty, and deficits in binocular visual function (whether transient or long-standing) have systematic effects on gaze strategy in complex terrains. We conclude that binocular vision provides useful information for locating footholds during locomotion. Furthermore, we have demonstrated that combined eye/body tracking in natural environments can be used to provide a more detailed understanding of the impact of a type of vision loss on the visuomotor control process of walking, a vital everyday task.

Purpose: To report a challenging case of medial rectus (MR) damage secondary to endoscopic sinus surgery (ESS). Methods: A 37-year-old woman presented with diplopia, exotropia, and adduction deficit of the right eye due to the right MR injury secondary to the ESS. Results: As a stepwise approach, she respectively underwent repairing of the damaged MR plus ipsilateral lateral rectus recession, half-tendon vertical rectus transposition to the MR insertion, and eventually nasal globe fixation with temporalis fascia that ultimately provided a single vision in the primary position with orthophoria. Conclusions: Re-establishment of an acceptable field of a single binocular vision in the context of iatrogenic MR injury is challenging and often requires multiple step-wise operations. Temporalis fascia is a safe and strong autogenous material, which can be used for globe fixation in this setting.

Most animals have at least some binocular overlap, i.e., a region of space that is viewed by both eyes. This reduces the overall visual field and raises the problem of combining two views of the world, seen from different vantage points, into a coherent whole. However, binocular vision also offers many potential advantages, including increased ability to see around obstacles and increased contrast sensitivity. One particularly interesting use for binocular vision is comparing information from both eyes to derive information about depth. There are many different ways in which this might be done, but in this review, I refer to them all under the general heading of stereopsis. This review examines the different possible uses of binocular vision and stereopsis and compares what is currently known about the neural basis of stereopsis in different taxa. Studying different animals helps us break free of preconceptions stemming from the way that stereopsis operates in human vision and provides new insights into the different possible forms of stereopsis.

BACKGROUND: The mortality rate due to road traffic accidents (RTA) is significantly high in Saudi Arabia (SA) compared to other countries. The visual function which includes good visual acuity (VA) and binocular vision are very important factors that can contribute to the incidence of RTA. AIM: The aim of this study is to investigate the association between refractive errors (REs) and the RTA in SA. METHODS: A total of 354 participants (mean age 22.67 ± 3.22 years) were recruited randomly to participate in this study from the population of Qassim district. Data collected using the questionnaire included participants’ age, sex, and education level, ocular and medical history, driving history as well as history of RTA. Ocular health examination including VA, RE measurements, and binocular vision function vision was measured and analyzed. RESULTS: The results of this study show that 48.3% of drivers had some form of REs with 3.4% being visually impaired. 217 (61.3%) of participants have had an RTA, and 119 (54.9%) of them have had more than two accidents in the past two years. The findings show no significant association between the occurrence of RTA and uncorrected REs or binocular vision dysfunction. CONCLUSION: Our data showed significantly higher rate of RTA among Saudi drivers which is much higher than any country in the world. The current Saudi regulations for obtaining driving license need to be modified, with implementing a comprehensive eye examination prior to acquiring or renewing drivers’ licenses.

BACKGROUND: Sheard and Percival assumed that symptoms from latent strabismus can be avoided if the relevant fusional vergence is adequate to support the heterophoria. AIM: The aim of the study was to determine the sensitivity and specificity of Sheard’s and Percival’s criterion for the diagnosis of heterophoria. METHODS: A cross-sectional hospital-based study was performed at Al-Neelain Eye Hospital Khartoum, Sudan from February to October 2019. Heterophoria was measured using Maddox Wing and fusional vergence using a prism bar. Thereafter, Sheard’s and Percival’s criteria were used for the diagnosis of heterophoria. RESULTS: A total of 230 participants (age = 15–30 years; mean age = 19.34 ± 3.325 years) were recruited for this study. The Sheard’s criteria showed a high sensitivity of 87.2% and a low specificity of 8.0% for the diagnosing of exophoria, with positive and negative predictive values of 65.5% and 26%, respectively. The criteria showed a relatively low sensitivity of 77.8% and a specificity of 9.0% in the diagnosis of esophoria, with a positive and negative predictive values of 56% and 20%, respectively. Percival criteria showed high sensitivity 84.2% and low specificity 9.1% in diagnosing esophoria, with a positive and negative predictive value of 61.5% and 25%, respectively. On the other hand, the criteria showed low sensitivity 67.4% and specificity 13.8% in diagnosing exophoria, with positive and negative predictive value 61.9% and 17%, respectively. CONCLUSION: Sheard’s and Percival’s criteria are useful in diagnosing binocular vision problems. Sheard’s criteria are accurate in diagnosing near exophoria and Percival’s criteria are more accurate in diagnosing near esophoria. Therefore, these criteria provide good clues and predictions for the diagnosis of binocular vision problems.

The binocular vision sensor composed of dual cameras is difficult to meet the requirements of synchronous image acquisition in dynamic high-speed measurement, and mirrored binocular vision sensor (MBVS) composed of single camera and catadioptric components have become popular among machine vision applications. Existing mirrored binocular vision sensors mostly comprise planar mirrors, which has the disadvantage of a small field-of-view (FOV). To extend the measurement range of the MBVS, we proposed a novel MBVS based on spherical catadioptric mirrors. The novel MBVS consists of a single camera and double spherical mirrors. The mathematical formula of the FOV of the MBVS is deduced, and the imaging light path is simulated. Then, the structural parameters of the sensor are calculated and a MBVS with a single camera and double spherical mirrors are designed. In order to preliminarily realize the distortion correction of spherical reflection imaging, the mathematical model of the MBVS is constructed. The accuracy of the calibration before and after spherical distortion correction is compared. Experimental results demonstrate the feasibility of the designed MBVS, which can extend the measurement range of the sensor.

La mesura de les vergències fusionals i de la relació AC/A són dos proves que ens permeten detectar possibles disfuncions o alteracions de la visió binocular. Les vergències fusionals ens proporcionen informació sobre l'estat binocular d'un individu i la capacitat de compensar la posició natural de repòs dels seus ulls, i la relació AC/A és la quantitat de convergència acomodativa induïda per un canvi en la resposta acomodativa. L’objectiu d’aquest treball és comparar si les vergències fusionals i l’AC/A varien segons l’error refractiu. Un total de 48 participants van participar a l’estudi (mitjana ± DS d’edat 20.56 ± 2.09 anys) que portaven la seva correcció habitual. Es va mesurar l’agudesa visual, l’amplitud d’acomodació, la flexibilitat d’acomodació, el punt proper de convergència, les vergències fusionals i la relació AC/A gradient estímul i resposta. Es va trobar una relació significativa entre l’amplitud acomodativa i l’error refractiu (p=0.01), on els emmetrops presenten valors majors que els miops. No es van observar diferències significatives entre les variables FA (p=0.89), PPC (p=0.22), ruptura BN i BT amb barra de prismes (p=0.16, p=0.44), ruptura BN i BT amb Risley (p=0.36, p=0.32) i l’error refractiu. Tot i que els emmetrops i els miops baixos van presentar canvis significatius en la fòria i l’AR amb l’addició de les lents de +2D, les relacions d’AC/A gradient resposta (p=0.68) i estímul (p=0.75) tampoc van ser influenciades pel rang d’errors refractius inclosos en aquest estudi. Això suggereix que el grup d’emmetrops i miops tenen respostes acomodatives i binoculars similars. La medida de las vergencias fusionales y de la relación AC/A son dos pruebas que nos permiten detectar posibles disfunciones o alteraciones de la visión binocular. Las vergencias fusionales nos proporcionan información sobre el estado binocular de un individuo y la capacidad de compensar la posición natural de reposo de los ojos, y la relación AC/A es la cantidad de convergencia acomodativa inducida por un cambio en la respuesta acomodativa. El objetivo de este trabajo es comparar si las vergencias fusionales y el AC/A varían según el error refractivo. Un total de 48 participantes participaron en el estudio (media ± DS de edad 20.56 ± 2.09 años) que llevaban su corrección habitual. El estudio se dividió en dos partes: la primera parte, con la muestra entera distribuida en: emétropes (-0.25D a +0.25D) (N=18) y miopes (-0.50D a -5.25D) (N= 30); y la segunda parte, con la muestra reducida distribuida en: emétropes (-0.25D a +0.25D) (N=15) y miopes bajos (-0.50D a -1.75D) (N=13). Se midió la agudeza visual, la amplitud de acomodación, la flexibilidad de acomodación, el punto próximo de convergencia, las vergencias fusionales y la relación AC/A gradiente estímulo y respuesta. Se halló una relación significativa entre la amplitud acomodativa y el error refractivo (p=0.01), donde los emétropes presentan valores mayores que los miopes. No se observaron diferencias significativas entre las variables FA (p=0.89), PPC (p=0.22), rotura BN y BT con barra de prismas (p=0.16, p=0.44), rotura BN y BT con Risley (p= 0.36, p=0.32) y el error refractivo. Aunque los emétropes y los miopes bajos presentaron cambios significativos en la foria y el AR con la adición de las lentes de +2D, las relaciones de AC/A gradiente respuesta (p=0.68) y estímulo (p= 0.75) tampoco fueron influenciadas por el rango de errores refractivos incluidos en este estudio. Esto sugiere que el grupo de emétropes y miopes tienen respuestas acomodativas y binoculares similares. The measurement of the fusional vergences and the AC/A ratio are two tests that allow us to detect possible dysfunctions or alterations in binocular vision. Fusional vergences provide us information about the binocular state of a subject, and the ability to compensate the natural resting position of their eyes, and the AC/A ratio is the amount of accommodative convergence induced by a change in accommodative response. The aim of this study wasto compare whether fusional vergences and AC/A vary according to refractive error. 48 subjects participated in the study (mean ± SD age 20.56 ± 2.09 years) who wore their usual correction. The study has been divided into two parts: the first part, with the entire sample distributed in: emmetropic (-0.25D to +0.25D) (N=18) and myopic (-0.50D to -5.25D) (N =30); and the second part, with the reduced sample distributed in: emmetropic (-0.25D to +0.25D) (N=15) and low myopic (-0.50D to -1.75D) (N=13). Visual acuity, amplitude of accommodation, flexibility of accommodation, near point of convergence, fusional vergences, and AC/A ratio gradient stimulus and response were measured. A significant relationship has been found between accommodative amplitude and refractive error (p=0.01), where emmetropic subjects present higher values than myopic. No significant differences were found between the variables FA (p=0.89), PPC (p=0.22), BI and BO break with prism bar (p=0.16, p=0.44), BI and BO break with Risley (p = 0.36, p=0.32) and refractive error. Although emmetropes and low myopes have presented significant changes in phoria and RA with the addition of +2D lenses, the AC/A gradient response (p=0.68) and stimulus ratios have not been influenced by the range of errors refractive included in this study. This suggests that the emmetropic and myopic group have similar accommodative and binocular responses.

For the wear and damage to mine conveyor belts by foreign materials, such as large materials, this paper designs a volume measurement method for large materials based on binocular vision by the volume measurement of the large material inon the conveyor belt, provides safety-warning data of over-volume limits for mine conveyor belts, and prevents damage to the mine conveyor belts. In this design, first, by obtaining the binocular camera parameters to improve the image-edge information, images taken with a binocular camera were then aligned by the Bouguet stereo correction algorithm. Finally, the disparity map was calculated by the semi-global-block matching (SGBM) stereo matching, and to get the target 3D coordinates, volume measurements were performed by the micrometric method. The study shows that the experimental error remains at about 5.65%, which provides a low-cost measurement method for raw-coal-volume measurement of the well industry and coal-mine belt conveyor.

Measuring the straightness of the scraper conveyor, which is an indispensable piece of equipment in a fully mechanized coal face, can prevent accidents such as derailment of the shearer and is also important for the precise positioning of the shearer and the accurate control of the hydraulic support. The existing scraper conveyor straightness measurement methods have the disadvantages of inconsistent measurement cost, accuracy, and reliability as well as low dimension of straightness description. To this end, this paper proposes a method for monitoring the three-dimensional straightness of a scraper conveyor based on binocular vision. Trapezoidal window matching technology was used to realize the image acquisition of multiple stations and multiple sensors. The bit pose acquisition model of binocular vision 3D reconstruction was used to obtain the 3D coordinates of the feature points on the sign board in each local coordinate system and the bit pose information of each sign board. The pose relay videometric method was used to convert the straightness in each local coordinate system to the global coordinate system to realize the 3D reconstruction of the scraper conveyor. Finally, the straightness measurement test of the preset scraper conveyor was carried out, and the error analysis was carried out by comparing with the manual measurement results, which showed that the measurement errors were all within ±30 mm. At the same time, the standard deviation of errors in both directions was small, which indicates that the straightness measurement method for the scraper conveyor in this paper has high reliability. In addition, the visual measurement process is independent of each other, so there is no error accumulation in the visual straightness measurement method. The analysis shows that the method of measuring the straightness of a scraper conveyor based on binocular vision can realize continuous and real-time monitoring of the scraper conveyor.

Aiming at the problem that the toe cap and upper part of the sole of a shoe easily appear missing when using binocular vision to reconstruct the shoe sole in the industrial production process, an improved matching cost calculation method is proposed to reconstruct shoe soles in three dimensions. Firstly, a binocular vision platform is built, and Zhang’s calibration method is used to obtain the calibration parameters. Secondly, the method of fusing Census and BT costs is used to calculate the matching cost of the image, so that the matching cost calculation result is more accurate. On this basis, 4-path aggregation is performed on the obtained cost, and the optimal matching cost is selected in combination with the WTA algorithm. Finally, left–right consistency detection and median filtering are used to optimize the disparity map and combine the camera calibration parameters to reconstruct the shoe sole in three dimensions. The experimental results show that the average mismatch rate of the four images on the Middlebury website in this method is about 6.57%, the reconstructed sole point cloud contour information is complete, and there is no material missing at the toe and heel.

This paper considers the three-dimensional (3D) shape measurement of metal parts during an additive manufacturing process in a direct energy deposition (DED) printing system with high temperature and strong light; a binocular measurement system based on ultraviolet light source projection is built using fringe projection and Fourier analysis. Firstly, ultraviolet light projection and an optical filter are used to obtain high-quality fringe patterns in an environment with thermal radiation. Then, Fourier analysis is carried out by using a single deformed fringe, and a spatial phase unwrapping algorithm is applied to obtain an unambiguous unwrapping phase, which is used as the guiding basis for the binocular matching process and 3D shape reconstruction. Finally, the accuracy of the measuring system is evaluated using a standard ball-bar gauge and the measurement error of this system is within 0.05 mm @ 100 × 100 mm. The results show that the system can measure 3D shape changes of metal parts in the additive manufacturing process. The proposed method and system have the potential to be used for online inspection and quality control of additive manufacturing.

Traditional nursery seedling detection often uses manual sampling counting and height measurement with rulers. This is not only inefficient and inaccurate, but it requires many human resources for nurseries that need to monitor the growth of saplings, making it difficult to meet the fast and efficient management requirements of modern forestry. To solve this problem, this paper proposes a real-time seedling detection framework based on an improved YoloV4 network and binocular camera, which can provide real-time measurements of the height and number of saplings in a nursery quickly and efficiently. The methodology is as follows: (i) creating a training dataset using a binocular camera field photography and data augmentation; (ii) replacing the backbone network of YoloV4 with Ghostnet and replacing the normal convolutional blocks of PANet in YoloV4 with depth-separable convolutional blocks, which will allow the Ghostnet–YoloV4 improved network to maintain efficient feature extraction while massively reducing the number of operations for real-time counting; (iii) integrating binocular vision technology into neural network detection to perform the real-time height measurement of saplings; and (iv) making corresponding parameter and equipment adjustments based on the specific morphology of the various saplings, and adding comparative experiments to enhance generalisability. The results of the field testing of nursery saplings show that the method is effective in overcoming noise in a large field environment, meeting the load-carrying capacity of embedded mobile devices with low-configuration management systems in real time and achieving over 92% accuracy in both counts and measurements. The results of these studies can provide technical support for the precise cultivation of nursery saplings.

Binocular summation in strabismic amblyopia is typically reported as being absent or greatly reduced in behavioral studies and is thought to be because of a preferential loss of excitatory interactions between the eyes. Here, we studied how excitatory and suppressive interactions contribute to binocular contrast interactions along the visual cortical hierarchy of humans with strabismic and anisometropic amblyopia in both sexes, using source-imaged steady-state visual evoked potentials (SSVEP) over a wide range of relative contrast between the two eyes. Dichoptic parallel grating stimuli modulated at unique temporal frequencies in each eye allowed us to quantify spectral response components associated with monocular inputs (self-terms) and the response components because of interaction of the inputs of the two eyes [intermodulation (IM) terms]. Although anisometropic amblyopes revealed a similar pattern of responses to normal-vision observers, strabismic amblyopes exhibited substantially reduced IM responses across cortical regions of interest (V1, V3a, hV4, hMT+ and lateral occipital cortex), indicating reduced interocular interactions in visual cortex. A contrast gain control model that simultaneously fits self- and IM-term responses within each cortical area revealed different patterns of binocular interactions between individuals with normal and disrupted binocularity. Our model fits show that in strabismic amblyopia, the excitatory contribution to binocular interactions is significantly reduced in both V1 and extra-striate cortex, whereas suppressive contributions remain intact. Our results provide robust electrophysiological evidence supporting the view that disruption of binocular interactions in strabismus or amblyopia is because of preferential loss of excitatory interactions between the eyes.SIGNIFICANCE STATEMENTWe studied how excitatory and suppressive interactions contribute to binocular contrast interactions along the visual cortical hierarchy of humans with normal and amblyopic vision, using source-imaged SSVEP and frequency-domain analysis of dichoptic stimuli over a wide range of relative contrast between the two eyes. A dichoptic contrast gain control model was used to characterize these interactions in amblyopia and provided a quantitative comparison to normal vision. Our model fits revealed different patterns of binocular interactions between normal and amblyopic vision. Strabismic amblyopia significantly reduced excitatory contributions to binocular interactions, whereas suppressive contributions remained intact. Our results provide robust evidence supporting the view that the preferential loss of excitatory interactions disrupts binocular interactions in strabismic amblyopia.

Monofixation syndrome (MFS) is a specific subnormal binocular vision status, either with or without a small deviation. Patients with MFS have a tendency to maintain stable ocular alignment. Correction of refractive errors and occlusion are considered as treatment option for amblyopia, and the status of MFS could be changed with long-term follow-up. The purpose of this study is to evaluate whether a Fresnel prism affected the visual acuity, angle of deviation, and sensory status in small-angle esotropia with subnormal stereopsis presenting with MFS features. Patients with small-angle esotropia within 8 prism diopters (PD) on the simultaneous prism and cover test from 2010 to 2019 were reviewed. Patients with subnormal stereopsis defined as more than 100 s of arc (arcsec) and with the central suppression with peripheral fusion were only included. A Fresnel prism was applied to the dominant eye, and the minimum follow-up period after Fresnel prism treatment was 24 months. We assessed patient clinical characteristics, course and response to therapy including visual acuity, angle of deviation, and stereopsis. Twenty patients with a mean age of 5.5 ± 1.4 years were included. The mean duration of Fresnel prism treatment was 15.3 ± 10.3 months. After 50.7 ± 17.2 months of follow-up, VA of the non-dominant eye was changed from 0.26 ± 0.20 logMAR to 0.07 ± 0.17 logMAR (P

The objective of this study was to identify the maturity and position of tomatoes in greenhouse. Three parts have been included in this study: building the model of image capturing and object detection, position identification of mature fruits and prediction of the size of the mature fruits. For the first part, image capturing in different time and object detection will be conducted in the greenhouse for identification of mature fruits. For the second part, the relative 3D position of the mature fruits calculated by the binocular vision was compared with the actual measured position. For the third part, the size of the bounding box from the object detection was compared with the actual size of the mature fruit, and the correlation was calculated in order to pre-adjust the width of the gripper for plucking operation in the future. The precision and the recall of the mature fruits of this study are over 95%. The average error of the 3D position is 0.5 cm. The actual size of the fruits and the R-squared of the size of the bounding box are over 0.9.

Our binocular world is seamlessly assembled from two retinal images that remain segregated until the cerebral cortex. Despite the coherence of this input, there is often an imbalance between the strength of these connections in the brain. ‘Eye dominance’ provides a measure of the perceptual dominance of one eye over the other. Theoretical models suggest that eye dominance is related to reciprocal inhibition between monocular units in the primary visual cortex, the first location where the binocular input is combined. As the specific inhibitory interactions in the binocular visual system critically depend on the presence of visual input, we sought to test the role of inhibition by measuring the concentrations of inhibitory (GABA) neurotransmitters during monocular visual stimulation of the dominant and the non-dominant eye. GABA-levels were acquired in V1 using a combined functional magnetic resonance imaging (fMRI) and magnetic resonance spectroscopy (MRS) sequence on a 7-Tesla MRI scanner. Individuals with stronger eye dominance had a greater difference in GABAergic inhibition between the eyes. This relationship was present only when the visual system was actively processing sensory input and was not present at rest. We provide the first evidence that imbalances in GABA levels during ongoing sensory processing are related to eye dominance in the human visual cortex. This provides strong support to the view that intracortical inhibition underlies normal eye dominance.SIGNIFICANCE STATEMENTWhat we see is shaped by excitation and inhibition in our brain. We investigated how eye dominance, the perceptual preference of one eye’s input over the other, is related to levels of inhibitory neurotransmitter GABA during monocular visual stimulation. GABAergic inhibition is related to eye dominance, but only when the visual system is actively processing sensory input. This provides key support for the view that imbalances in visual competition that are observed in the normal visual system arise from an inability of GABA signalling to suppress the stronger sensory representation.

SIGNIFICANCE The range of clear and single binocular vision differs between 3D displays and clinical prism vergences, but this difference is unexplained. This difference prevents clinicians from predicting the range of clear and single binocular vision in 3D-viewing patients. In this study, we tested a hypothesis for this difference. PURPOSE The purpose of this study was to determine whether changing fixation target size in 3D viewing significantly affects the vergence ranges and, if so, then to determine whether the target size effect is driven by fusional vergence gain changes, threshold of blur changes, or both. METHODS Twenty-one visually normal adults aged 18 to 28 years viewed 3D images at 40 cm in an electronic stereoscopic. The fixation target, a Maltese cross, moved in depth at 2∆/s by way of changing crossed or uncrossed disparity until blur and diplopia ensued. We used four target sizes: (1) small (width × height, 0.21° × 0.63°), (2) medium (1.43° × 4.3°), (3) large (3.6° × 10.8°), and (4) 3D (size changing congruently with disparity). The effect of target size on responses was tested by mixed ANOVAs. RESULT Mean convergence blurs and breaks increased with target size by 40% (P < .001) and 71% (P < .001), respectively, and in divergence by 33% (P = .03) and 30% (P = .04), respectively. The increases in break magnitude with target size implicate fusional vergence gain change in the size effect. Increasing target size raised the threshold of blur from 1.06 to 1.82 D in convergence and from 0.97 to 1.48 D in divergence (P = .008). CONCLUSIONS Growing fixation target size in 3D viewing increases fusional vergence gain and blur thresholds, which together increase the limits of clear and single binocular vision. Therefore, the clarity of a 3D image depends not only on its disparity but also on the size of the viewed image.

To evaluate the treatment efficacy of the preoperative base-out recovery point as the surgical target angle for acute acquired comitant esotropia.Prospective study. Twenty-two patients with acute acquired comitant esotropia (AACE) underwent strabismus surgery based on the target angle of the preoperative base-out recovery point. The postoperative deviation, positive fusional vergence, and negative fusional vergence were evaluated and compared with those of 23 normal individuals.The mean follow-up period was 18.68 ± 19.48 months. At the last follow-up, 19 (86.4%) of 22 subjects had orthophoria, whereas 3 (13.6%) had minimal esophoria. The postoperative angle of deviation was significantly smaller than the preoperative angle of deviation at near (P 0.001) and distance (P 0.001). Postoperative sensory fusion was significantly better than preoperative fusion at near (P 0.001) and distance (P 0.001). The postoperative stereoacuity improved significantly after the surgery at near (P 0.001) and distance (P 0.001). Compared with the controls, the convergence and divergence amplitudes in the AACE patients were similar at distance (P 0.05) but were still narrower at near (P 0.001).Good alignment and binocular balance were obtained with the surgical target angle of the base-out recovery point in AACE.