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We present a probabilistic framework for detailed 3-D shape estimation and tracking using only vision measurements. Vision detections are processed via a bird’s eye view representation, creating accurate detections at far ranges. A probabilistic model of the vision based point cloud measurements is learned and used in the framework. A 3-D shape model is developed by fusing a set of point cloud detections via a recursive Best Linear Unbiased Estimator (BLUE). The point cloud fusion accounts for noisy and inaccurate measurements, as well as minimizing growth of points in the 3-D shape. The use of a tracking algorithm and sensor pose enables 3-D shape estimation of dynamic objects from a moving car. Results are analyzed on experimental data, demonstrating the ability of our approach to produce more accurate and cleaner shape estimates.

The light irradiated into a translucent object is multi-reflected inside and then emitted from a position different from the incident position. This behavior is called subsurface scattering. Understanding subsurface scattering behavior is very important in the measurement of three-dimensional (3-D) shapes and CG representations of translucent objects. In this study, we simulated the subsurface scattering of translucent objects using the ray tracing method, and examined a shape-measurement method for 3-D translucent objects by the spotlight projection method using the simulation results.

We demonstrate precise passive rotational alignment of multi-core fibres (MCFs) with double-D-shape cladding on V-groove arrey. Eight MCFs were simultaneously aligned with small rotational misalignments, and achieved the insertion losses of < 0.5 dB in 16 outer cores.

We developed a multi-core fibre with a concaved double-D shape cladding for passive fibre alignment. The cladding dimensions were well controlled in longitudinal and transverse directions, with 150-m/min drawing speed which is the highest ever reported for the rectangular-like fibre.

We achieved 51-nm bandwidth noise-like pulse using a polarized graphene saturable absorber made of gold-coated graphene on D-shape fibre. By launching the high energy noise-like pulse into high nonlinear fibre, 1000-nm wide supercontinuum spectrum was obtained.

This paper proposes a fast motion-compensated structured-light method that realizes 3-D shape measurement of moving object at 500 frames per second (fps) by using a high-frame-rate synchronized camera-projector system. In this method, multiple light patterns coded with an 8-bit gray code are projected on the measured scene at 1000 fps; images captured simultaneously are processed in real time for generating 512×512 depth images at 500 fps by introducing the parallel processing approach on a GPU board. Experiments were performed on moving object to verify the effectiveness of the proposed method.

We propose a novel dot-pattern-projection three-dimensional (3-D) shape measurement method that can measure 3-D displacements of blink dots projected onto a measured object accurately even when it moves rapidly or is observed from a camera as moving rapidly. In our method, blinking dot patterns, in which each dot changes its size at different timings corresponding to its identification (ID) number, are projected from a projector at a high frame rate. 3-D shapes can be obtained without any miscorrespondence of the projected dots between frames by simultaneous tracking and identification of multiple dots projected onto a measured 3-D object in a camera view. Our method is implemented on a field-programmable gate array (FPGA)-based high-frame-rate (HFR) vision platform that can track and recognize as much as 15×15 blink-dot pattern in a 512×512 image in real time at 1000 fps, synchronized with an HFR projector. We demonstrate the performance of our system by showing real-time 3-D measurement results when our system is mounted on a parallel link manipulator as a sensing head.

Three-dimensional (3D) shape models have recently been used in various fields including machine designing, internet mall, and medical application. Therefore, efficient management and reuse of 3D shape models is becoming important with research on object searching of 3D shape models. 3D shape model searching requires taking into consideration rotation, scaling, and translation of models. This paper proposes a method to search 3D objects to include and account for the above conditions. The proposed method acquires 2D range images by rendering a 3D object from many viewpoints, and discretely approximating two of the three degrees of rotational freedom by a finite number of viewpoints. Using the phase correlation method on the range image one can estimate the rotation around one axis, include scaling and translation, and compare the similarities between the input with models in a dictionary. Experimental results show that whether models match or not match can be distinguished even when the supposed viewpoints are limited to a finite number.

Nano-level 3-D measurement is one of the key technologies for the current and future generation of production systems for semi-conductors, LCDs and nano-devices. To meet with these applications, wide range nano-level 3-D shape measurement method using combination of RGB lights has been developed. It measures the height of nano-objects using RGB lights interference color fringes. To analyze the RGB color fringes, the adaptive phase analysis method of interference fringes has been developed and achieved its efficiency. But it cannot measure the shape of edges. To meet with the difficulty, the color analysis method on xy-color plane has been introduced. The combination of the phase measurement method and the color analysis method has measured the 4 micrometer columns precisely. As more practical application, the shape of needles for AFM has been extracted, successfully.

In this paper, we present a statistical analysis of the problem of shape reconstruction from measurements of the brightness function by using the Cramer-Rao lower bound on the 3-D boundary. The Cramer-Rao lower bound analysis presented here provides statistical estimates that can be used for performance evaluation of algorithms.

High-speed, high-resolution 3-D shape measurement becomes increasingly important, with broad applications including medicine, homeland security, and entertainment. In recent years, we have made some progress, and developed an unprecedented 60 Hz rate 3-D shape measurement system with a digital fringe projection and phase-shifting method. However, a hardware bottleneck was met to further improve its speed. Since 2009, we have been studying a new method that could potentially eliminate this speed bottleneck. This technique is essentially to generate sinusoidal fringe patterns by properly defocusing binary ones. It coincides with the operation mechanism of the digital-light-processing (DLP) technology, and thus permits some speed breakthroughs. This paper summarizes some of our recent studies with this technology. In particular, we will include three major pieces: (1) double the speed of our real-time 3-D shape measurement system without significantly increase the hardware cost; (2) reach tens-of-kHz rate 3-D shape measurement by using a relatively inexpensive and off-the-shelf DLP projector; and (3) achieve kHz rate phase shifting for superior high-speed, high-quality 3-D shape measurement with the DLP Discovery platform. We will explain the principles of the technology, show some experimental results, and discuss the advantages and shortcomings of this technology.

A lot of plumbings such as gas pipes and water pipes exist in public utilities, factories, power plants and so on. It is difficult for humans to inspect them directly because they are long and narrow. Therefore, automated inspection by robots equipped with camera is desirable, and great efforts have been done to solve this problem. However, many of existing inspection robots have to rotate the camera to record images in piping because a conventional camera with a narrow view can see only one direction while piping has a cylindrical geometry. The use of an omni-directional camera that can take images of 360° in surroundings at a time is effective for the solution of the problem. However, the shape measurement is difficult only with the omni-directional camera. Then, in this paper, we propose a reconstruction method of piping shape by using an omni-directional camera and an omni-directional laser with a light section method and a structure from motion analysis. The validity of the proposed method is shown through experiments.

A triangulation-based laser rangefinder is able to achieve a favorable balance between measurement accuracy and measurement. time. However, it. is known that conventional triangulation-based rangefinder has difficulty applying to 3-D shape measurement of specular objects with shiny surface. We previously proposed two approaches to overcome the above problem that conventional triangulation-based rangefinder cannot apply to 3-D shape measurement of specular objects. It is true that the previously proposed approaches allowed to measure the 3-D shape of specular objects, but their approaches have leaved the some problems that needs to be solved. In this paper, we propose a novel rangefinding approach which does not cause the above errors for specular objects, compared to the previous approach. The basic concept of the proposed approach is to detect the position and incident angle of a light spot by using a newly-devised sensor and derive an inverse raytracing equation by rigorous geometric optics analysis.

An original procedure is presented for calibrating fringe projection-based 3D vision systems. The approach estimates both the phase-to-depth and transverse relationships by using the phase maps calculated for only three planes placed within the calibration volume. Experimental tests conducted on a fringe projection system show the effectiveness of the proposed procedure.

A real-time 3-D full-field shape measurement technique based on a generalized fringe projection profilometry is presented. The technique has the following features: high accuracy, real-time measurement, low cost, and easy implementation.

The display of the colonoscope shape inside human body is a new technique under development which helps the doctor to judge visually if the patient colon is in normal situation or tends to twist the colonoscope into an unusual and unsafe shape. This paper presents a real-time shape reconstruction method based on biber Bragg grating (FBG) sensor array and a positioning technique of colonoscope's handle part by means of binocular vision, while the colonoscope inserted into human colon. Detailed analysis include the detecting principles, spatial curve reconstruction algorithm from the information of FBG sensors, and estimation of pose of the handle part of the colonoscope relative to the world frame. Experimental results demonstrate the effectiveness of the proposed techniques. With an accuracy of shape reconstruction to be improved to 4.5 mm compared with earlier research. By adding the pose detecting subsystem for the colonoscope's handle part, the 3D shape display subsystem will work more effectively and become more practical.

This paper presents an integrated framework for recognizing 3D human posture from 2D images. A flexible combinational algorithm motivated by the novel view expressed by Cyr and Kimia (2004) is proposed to generate the aspects of 3D human postures as the posture prototype using features extracted from the collected 2D images sampled at random intervals from the viewing sphere. Frequency and phase information of the posture are calculated from the Fourier descriptors (FDs) of the sampled points on the posture contour as the main and assistant features to extract the characteristic views as the aspects. Moreover, a modified particle filter is applied to improve the robustness of human posture recognition for continuous monitoring. Experimental trials on synthetic and real sequences have shown the effectiveness of the proposed method.

The optical laser displacement sensor is a measurement sensor that is widely used to measure the 3-D shape profile of the object surface as a non-contact type. When the surface of objects has large slope variation, the sensor gain is varied with respect to the slope variation of the object surface. In order to solve the sensor gain variation problem for the object surface having the slope variation, the constant gap control method can be applied to adjust the gap to the nominal distance. Then, compared with the constant sensor height method, the constant gap control method can reduce the variation of the sensor gain. It can also reduce the measurement range of the sensor, so the accuracy of height measurement increases.

This article describes an analytical method of predicting a processed structural shape by a double exposure technique in deep X-ray lithography (D2XRL). Firstly, the concept of calculating the processed shape efficiently by simple equations was considered. Secondly, important functions composing the simple equations, i.e., absorbed dose as a function of depth and dissolution rate as a function of absorbed dose, were experimentally determined with high accuracy by a newly proposed method. Lastly, the processed shape was predicted by the analytical method. By comparing the predicted result with the experimental one under the same condition, we confirmed that the processed shape was predicted with acceptable accuracy.

In this paper, we propose a new laser rangefinder equipped with a 6-axis robot and a new sensor that has ability of detecting both the 2-D incident angle and the 2-D position of a light. It is difficult for an ordinary rangefinder to measure the 3-D shape of a specular object. Then we propose the rangefinder that can measure the 3-D position (x, y, z) of specular and Lambertian objects from x-z coordinate triangulation and y-z coordinate one. It is clear that the proposed rangefinder has a great potential for the 3-D shape measurement of a complex-shape specular object.

In this paper, we propose a method of measuring 3D shape and refractive index of a transparent object using a triangulation-based rangefinder. The rangefinder is based on the fact that the light projected onto the surface of a transparent object is partly reflected by the surface, though the majority of the projected light is transmitted through the surface. The measuring principle is to detect the reflected light and the transmitted light from a transparent object, and to apply our proposed triangulation to these lights. We built a prototype rangefinder and confirmed the efficacy of this method. As a result, we conclude that the proposed approach has great potential for a wide range of industrial applications

In the field of 3-D image measurement, a technique based on stripe pattern projection and observation image intensity analysis is expected to be able to detect several stripes by a single projection. It is necessary to increase the stripe number of the projection pattern in order to improve the measurement accuracy of depth distance. However, when the stripe number is increased, the difference of the intensity between stripes will be reduced and stripe detection will become difficult. In order to improve the detection accuracy of the stripe order and shorten the 3-D measurement time, we use the Optimal Intensity-Modulation Projection (OIMP) technique, and in order to improve the depth distance measurement accuracy, we propose an Intensity-Phase Analysis (IPA) technique. In the proposed IPA technique, the observation pattern be segmented by the intensity of the intensity-modulated stripe, and in every segmentation the depth distance of all pixels are obtained by phase analysis. By using a combination of the OIMP and IPA techniques, high-speed (single projection and double image captures) and high-accuracy (error less than 0.1%) practical 3-D shape measurement can be realized.

In this paper, we propose a new method of measuring 3-D shape and refractive index of a transparent object using a triangulation-based rangefinder. The rangefinder is based on the fact that the light projected onto the surface of a transparent object is partly reflected by the surface, though the majority of the projected light is transmitted through the surface. The basic principle for measuring 3-D shape and refractive index is to detect the reflected light and the transmitted light from a transparent object using specially developed image sensor for this measurement, and to apply our proposed triangulation equation and refractive index equation to these lights. We built a prototype rangefinder and confirmed the efficacy of this method. As a result, we conclude that the proposed approach has great potential for a wide range of industrial applications.

Tactile display which displays character and graphic information dynamically from computer by making pins array up and down has been developed. Shape Memory Alloy (SMA) micro-coil actuators contract and make the pins up and down when an electrical current is supplied. Magnetic material tube is attached to each pin and a permanent magnet fixes position of the pins up or down. Electrical consumption is low because the current is supplied only when the pins move. A 2-D tactile display which has 100 (10/spl times/10) pins array has been developed and successfully operated. The tactile information were displayed sequentially every 0.3 second and the pins were latched at 0.1 N by magnetic force. The pins are arranged at a pitch of 2.5 mm and move 2 mm up and down individually. In order to present the tactile information accurately, narrower pin pitch of the tactile display is preferable. A module for tactile display with a pin pitch of 1.27 mm has been fabricated and successfully operated. A multi-step magnetic latch has been developed for a 3-D tactile display. By using these mechanisms, large displacement and accurate positioning of the pin for 3-D expression can be realized.

The present paper describes a newly proposed method for simultaneously measuring 3D shape and surface reflectance of an object using a laser rangefinder. The original work of this method lies in the advantage that the proposed method measures the surface reflectance using the object itself that is used for the 3D shape measurement. Experimental results show that the proposed method was applicable to noncontact industrial inspection, robot vision in automatic assembly, and reverse engineering.

This paper presents 3D shape modeling using surface parameterization by spherical harmonics and the combination of superquadric and spherical harmonics . Although, the results obtained with the two representation schemes are comparable, we opt for the spherical harmonics model. Our approach is divided into two parts. The first consists in extracting set of 3D points which corresponds to epicardium and endocardium wall respectively. For this purpose, we have segmented the original SPECT myocardium data. The second part consists in fitting the surface on this set of unstructured 3D points using the both methods: a parametric surface description using (SH) and a combination of two models (SQ-SH).

Shape remains a major descriptive and discriminant feature of objects, especially in clinical settings where it forms an integral part (for example) of radiological morphometry as well as anthropometry and biometrics. Most successful descriptions of shape are functional rather than descriptive, and it is often the goal that any such functional description of shape be unique (but generalizable, see below) as well as invariant under some (or all) rigid motions of the base object. When these goals are combined with a desire to keep the descriptor reasonably computationally efficient then often a compromise had to be made in which one or other of the goals is relaxed. In this paper we describe a vectorial formulation of an invariant shape descriptor which is reasonably computationally efficient but for which we cannot guarantee absolute uniqueness. Our setting is a wide class of three-dimensional (polyhedral) objects drawn from such datasets as the visible human datasets and the CAESAR/CARDLab anthropometric datasets. In this short paper we describe the formal definition of a set of vectorial spherical shape descriptors, and give preliminary indications of their role in shape description in anthropometry.

In this paper, a reconstruction method of a curved object from a single gray-level image is proposed. To realize easy but robust shape from shading (SFS), the proposed method adopts isodensity lines. The results of computer simulation using virtual objects show that the prospects of using this method are very encouraging.

In this paper, the framework of a 3-D shape reconstruction software system used in biomedical research is reported. The system mainly includes two packeges: 2-D contours extraction and 3-D shape reconstruction. The new methods used in this system are described. This paper also shows the application of the system in neuro-physiology research and medical CT images.

A 3-D shape analysis system using moire topography technique is described and its application in 3-D measurement of the face is presented. With this system 80 moire patterns of a human face with normal morphology are analyzed and the statistical parameters on a number of feature points on the face are obtained. Some important problems encountered in this application are discussed. >