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In taekwondo, poomsae (i.e., form) competitions have no quantitative scoring standards, unlike gyeorugi (i.e., full-contact sparring) in the Olympics. Consequently, there are diverse fairness issues regarding poomsae evaluation, and the demand for quantitative evaluation tools is increasing. Action recognition is a promising approach, but the extreme and rapid actions of taekwondo complicate its application. This study established the Taekwondo Unit technique Human Action Dataset (TUHAD), which consists of multimodal image sequences of poomsae actions. TUHAD contains 1936 action samples of eight unit techniques performed by 10 experts and captured by two camera views. A key frame-based convolutional neural network architecture was developed for taekwondo action recognition, and its accuracy was validated for various input configurations. A correlation analysis of the input configuration and accuracy demonstrated that the proposed model achieved a recognition accuracy of up to 95.833% (lowest accuracy of 74.49%). This study contributes to the research and development of taekwondo action recognition.

Marine bioprospecting is the procedure of identifying the characteristics of marine organisms to develop them into commercial products. This paper proposes a 3D reconstruction algorithm to facilitate 3D visualization of underwater scene for the marine bioprospecting using remotely operated underwater vehicle (ROV). It allows to provide an operator with intuitive user interface and accordingly contribute to enhance the operability of the ROV in the bioprospecting operation. The reconstruction algorithm transforms 2D pixel coordinates of the sonar image into the corresponding 3D spatial coordinates of the scene surface by restoring the surface elevation missing in the sonar image. First, the algorithm segments the objects and shadows in the image by classifying the pixels based on the intensity value of the seafloor. Second, it computes the surface elevation on the object pixels based on their intensity values. Third, the elevation correction factor, which is derived by the ratio between height of the object and the length of the shadow, is multiplied to the surface elevation value. Finally, the 3D coordinates of the scene surfaces are reconstructed using the coordinate transformation from the image plane to the seafloor with the restored surface elevation values. The experimental results show the algorithm successfully reconstructs the surface of the reference object within an error range less than 10 % of the object dimension, and practical applicability to the marine bioprospecting operation.

Muscle synergy is the association of several muscle groups contracting simultaneously as a single functional unit. Recently, the synergy has been emphasized in neurophysiological studies to utilize it as an evaluation index for stroke patients. In this paper, we proposed novel method for quantitatively comparing muscle synergy of normal people and the stroke patient for evaluating severity of the stroke. The proposed method uses NNR (Non-Negative Matrix Reconstruction) algorithm for reconstructing muscle weight matrix W. The proposed method synchronizes the time sequence of EMG data of the stroke patient with the normal people based on working phases. The method improves the distortion problem of NNR algorithm through the synchronization of time sequence.

This paper focuses on the human perception capabilities for haptic interaction with remote environments. The perception capabilities are compared for two well-known control methods with two kinds of haptic cues. Analytical and psychophysical methods are used to analyze the performance. The first control method aims at maximizing the transparency of the remote interactions (i.e., transparency-based method ), whereas the second one aims at maximizing the detection and discrimination abilities of the human operator (i.e., perception-based method ). For each of these two control methods, two kinds of haptic cues are studied, which use position and force cues from remote environments. Hybrid matrix formulation is employed, and it is analyzed in the frequency domain for these studies. Psychophysical experiments are then conducted for human-centered evaluation and comparison of the control methods. Analytical and experimental results clearly show that the perception-based method, when compared with the transparency-based method, enhances the human operator's perceptual capabilities of remote environments irrespective of force cues. For each of the two control methods, the force cues always contribute more to the increase in perceptual sensitivity when compared with the case of position cues.

Careful planning of operations is critical to success of the closed reduction and internal fixation (CRIF) surgery to fix proximal femur fractures. This paper presents a novel surgery planning simulation for the CRIF. The developed simulation employs 3D femur model reconstructed from actual patient's CT data, and enables the user to make a plan on the model using 2D mouse. A projection scheme is developed to map a selected point on the monitor screen onto the 3D femur model. A centerline of the femur neck and cross section images are provided to help the user make optimal planning. The centerline of the femur neck is extracted by connecting two center points of cross sections selected by the surgeon. The cross section image is generated using intersection points between the femur model and a plane selected by the user. The simulation also displays post-operative appearance of the femur using 3D implants models.

SUMMARYIn this paper, human viscosity perception in haptic teleoperation systems is thoroughly analyzed. An accurate perception of viscoelastic environmental properties such as viscosity is a critical ability in several contexts, such as telesurgery, telerehabilitation, telemedicine, and soft-tissue interaction. We study and compare the ability to perceive viscosity from the standpoint of detection and discrimination using several relevant control methods for the teleoperator. The perception-based method, which was proposed by the authors to enhance the operator's kinesthetic perception, is compared with the conventional transparency-based control method for the teleoperation system. The fidelity-based method, which is a primary method among perception-centered control schemes in teleoperation, is also studied. We also examine the necessity and impact of the remote-site force information for each of the methods. The comparison is based on a series of psychophysical experiments measuring absolute threshold and just noticeable difference for all conditions. The results clearly show that the perception-based method enhances both detection and discrimination abilities compare with other control methods. The results further show that the fidelity-based method confers a better discrimination ability than the transparency-based method, although this is not true with respect to detection ability. In addition, we show that force information improves viscosity detection for all control methods, as predicted from previous theoretical analysis, but improves the discrimination threshold only for the perception-based method.

This paper presents a new design and analysis of a haptic interface for a gastrointestinal endoscopy simulation. The gastrointestinal endoscopy is a procedure in which the digestive tract and organs of a patient are diagnosed and treated using a long and flexible endoscope. The developed haptic interface incorporates two degrees of freedom (DOF), each of which is necessary to describe the movements of an endoscope during the actual endoscopy procedures. The haptic interface has a translational motion mechanism to implement the insertion movement of the endoscope, and a rotational motion mechanism to implement the rotational movement of the endoscope. The endoscope included in the haptic interface is supported by a folding guide to prevent the endoscope from buckling. Force feedback in each direction is provided by wire-driven mechanisms. The developed haptic interface has a workspace, sensitivity, and maximum attainable force and torque enough to simulate the endoscopy procedures such as colonoscopy, upper GI (gastrointestinal) endoscopy, and endoscopic retrograde cholangiopancreatography (ERCP). The developed haptic interface is applied to implementation of a colonoscopy simulation. Performance including force bandwidth is evaluated through experiments and simulation.

International audience; The relevance of haptic feedback for minimally invasive surgery has been demonstrated at numerous counts. However, the proposed methods often prove inadequate to handle correct contact computation during the complex interactions or topological changes that can be found in surgical interventions. In this paper, we introduce an approach that allows for accurate computation of contact forces even in the presence of topological changes due to the simulation of soft tissue cutting. We illustrate this approach with a simulation of cataract surgery, a typical example of microsurgery.

This paper discusses the methods for real-time rendering of time-varying dynamic fluoroscope images including fluid flow for the ERCP (Endoscopic Retrograde Cholangiopancreatography) simulation. A volume rendering technique is used to generate virtual fluoroscopy images. This paper develops an image-overlaying method which overlaps the timevarying images onto the constant background image. The full size fluoroscopy image is computed from the initial volume data set during the pre-processing stage, which is then saved as the background image. Only the time-varying images are computed from the time-varying volume data set during the actual simulation. This involves relatively small computation compared with the background image. The time-varying images are then overlaid onto the background image to obtain the complete images. This method reduces computational overhead by removing redundant computations. A simplified particle dynamics model is employed for fast simulation of the fluid flow. The fluid model, a collection of particles, interacts only with the ducts based on principles of a complete elastic collision. Hence, the velocity of the particles, when they collide with the duct, can be computed by using simple algebraic equations. The methods are implemented for fast simulation of the ERCP.