Hand Modeling and Motion Reconstruction for Individuals

2014 ◽  
Vol 8 (3) ◽  
pp. 376-387 ◽  
Author(s):  
Yui Endo ◽  
◽  
Mitsunori Tada ◽  
Masaaki Mochimaru
Keyword(s):  
Motion Capture ◽  
Local Coordinate System ◽  
Skin Surface ◽  
Tetrahedral Mesh ◽  
Surface Model ◽  
Motion Capture System ◽  
Joint Rotation ◽  
Link Structure ◽  
Hand Model ◽  
The Individual

In this paper, we propose a new method of reconstructing hand models for individuals including link structure models, homologous skin surface models and homologous tetrahedral mesh models in a reference posture. The skin surface model is defined as a threedimensional triangularmesh, obtained by deforming a template mesh so as to fit the landmark vertices to the corresponding marker positions obtained by a motion capture system. In this process, anatomical dimensions for the subject, manually measured by a caliper, are also used as the deformation constraints. As for the link structure model, the local coordinate system related to each link consists of the joint rotation center and the axes of joint rotation, which can be estimated based on the deformation of the skin surface of the template model relative to the one of the individual. By using obtained individual hand model, hand postures in a motion sequence are also reconstructed based on the landmark points and the corresponding marker positions obtained from the motion capture system. Virtual spring-damper models located between the landmarks and the markers are used in physically-based simulation for the posture reconstruction.

scholarly journals Reconstructing individual hand models from motion capture data

2014 ◽  
Vol 1 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Yui Endo ◽  
Mitsunori Tada ◽  
Masaaki Mochimaru
Keyword(s):  
Motion Capture ◽  
Local Coordinate System ◽  
Surface Region ◽  
Skin Surface ◽  
Tetrahedral Mesh ◽  
Surface Model ◽  
Motion Capture System ◽  
Joint Rotation ◽  
Link Structure ◽  
The Subject

Abstract In this paper, we propose a new method of reconstructing the hand models for individuals, which include the link structure models, the homologous skin surface models and the homologous tetrahedral mesh models in a reference posture. As for the link structure model, the local coordinate system related to each link consists of the joint rotation center and the axes of joint rotation, which can be estimated based on the trajectories of optimal markers on the relative skin surface region of the subject obtained from the motion capture system. The skin surface model is defined as a three-dimensional triangular mesh, obtained by deforming a template mesh so as to fit the landmark vertices to the relative marker positions obtained motion capture system. In this process, anatomical dimensions for the subject, manually measured by a caliper, are also used as the deformation constraints.

Placement of Composed LED Light Sources for an Inverse Triangulation Motion Capture System with Reflexive Spherical Markers

2016 ◽  
Vol 841 ◽  
pp. 139-144
Author(s):  
Constantin Radu Mirescu ◽  
Gabriela Roșca
Keyword(s):  
Gait Analysis ◽  
Motion Capture ◽  
Video Camera ◽  
Light Sources ◽  
Iterative Approach ◽  
Motion Capture System ◽  
Led Light ◽  
Pixel Array ◽  
The Individual ◽  
The Way

This paper investigates the problem of composed LED light sources placement for a particular case of motion capture with reflexive spherical markers in Gait Analysis in a controlled lighted environment. After the addressed problem is introduced the way the rays are propagated from the individual LEDs to the pixel array of video camera is computed. Based on this calculus the number of ray hits on distinct pixels is computed for a marker placed in the workspace. Next by varying some scene parameters we obtain the total number of hits on the overall set of makers placed in the scene and based on this number we obtain finally the best placement for the composed LED light sources using an iterative approach.

A Normative Database of Thumb Circumduction in Vivo: Center of Rotation and Range of Motion

2002 ◽  
Vol 46 (13) ◽  
pp. 1167-1171 ◽  
Author(s):  
Peter Braido ◽  
Xudong Zhang ◽  
Robert Hefner ◽  
Mark Redden
Keyword(s):  
Range Of Motion ◽  
Motion Capture ◽  
Local Coordinate System ◽  
Hand Movement ◽  
Three Dimensional ◽  
Biomechanical Modeling ◽  
Motion Capture System ◽  
Normative Database ◽  
Center Of Rotation

This study aimed to explore the use of a contemporary motion capture system for measuring in vivo maximum thumb circumduction, and through biomechanical modeling and statistical analysis, to establish a normative database of three-dimensional functional thumb range of motion (ROM) and examine the effects of anthropometry and gender. Twenty-eight (14 males and 14 females) anthropometrically diversified subjects performed maximum voluntary thumb circumductions, as the trajectories of surface markers placed on their thumb landmarks were measured by an opto-electronic motion capture system. Aglobographic representation method determined the best fitting spheres, the center of rotation (COR) expressed in a local coordinate system, and reference axes of thumb circumduction. Thumb ROM was quantified using (1) the cone volume circumscribed by the thumb, and (2) the time-varying included angle with respect to a reference axis, expressed as the joint sinus. Statistical analyses suggest that gender is the most important factor ( p < 0.05) in determining the COR while anthropometry has the most significant effect on the cone volume ( p < 0.0001), but neither affects the joint sinus measures. The results provide valuable data as well as insights for biomechanical modeling of hand movement, ergonomic design of hand-operated controls or devices, and evaluation of thumb impairments or disorders.

Gender differences in the Achilles tendon load during the fencing lunge

2014 ◽  
Vol 6 (3) ◽  
Author(s):  
Jonathan Kenneth Sinclair ◽  
Lindsay Bottoms
Keyword(s):  
Gender Differences ◽  
Achilles Tendon ◽  
Motion Capture ◽  
Tendon Injury ◽  
Force Platform ◽  
Motion Capture System ◽  
3D Motion ◽  
Loading Rates ◽  
Tendon Pathology ◽  
3D Motion Capture

AbstractRecent epidemiological analyses in fencing have shown that injuries and pain linked specifically to fencing training/competition were evident in 92.8% of fencers. Specifically the prevalence of Achilles tendon pathology has increased substantially in recent years, and males have been identified as being at greater risk of Achilles tendon injury compared to their female counterparts. This study aimed to examine gender differences in Achilles tendon loading during the fencing lunge.Achilles tendon load was obtained from eight male and eight female club level epee fencers using a 3D motion capture system and force platform information as they completed simulated lunges. Independent t-tests were performed on the data to determine whether differences existed.The results show that males were associated with significantly greater Achilles tendon loading rates in comparison to females.This suggests that male fencers may be at greater risk from Achilles tendon pathology as a function of fencing training/ competition.

Magnetic motion capture system using LC resonant magnetic marker composed of Ni–Zn ferrite core

2006 ◽  
Vol 99 (8) ◽  
pp. 08B312 ◽  
Author(s):  
S. Hashi ◽  
M. Toyoda ◽  
M. Ohya ◽  
Y. Okazaki ◽  
S. Yabukami ◽  
...  
Keyword(s):  
Motion Capture ◽  
Motion Capture System ◽  
Ferrite Core ◽  
Zn Ferrite ◽  
Magnetic Marker

scholarly journals Modeling and evaluating beat gestures for social robots

2021 ◽  
Author(s):  
Unai Zabala ◽  
Igor Rodriguez ◽  
José María Martínez-Otzeta ◽  
Elena Lazkano
Keyword(s):  
Motion Capture ◽  
Motion Capture System ◽  
Generative Adversarial Network ◽  
Adversarial Network ◽  
Desirable Feature ◽  
Quantitative Results ◽  
Path Lengths ◽  
End Effectors ◽  
The One ◽  
Made In

AbstractNatural gestures are a desirable feature for a humanoid robot, as they are presumed to elicit a more comfortable interaction in people. With this aim in mind, we present in this paper a system to develop a natural talking gesture generation behavior. A Generative Adversarial Network (GAN) produces novel beat gestures from the data captured from recordings of human talking. The data is obtained without the need for any kind of wearable, as a motion capture system properly estimates the position of the limbs/joints involved in human expressive talking behavior. After testing in a Pepper robot, it is shown that the system is able to generate natural gestures during large talking periods without becoming repetitive. This approach is computationally more demanding than previous work, therefore a comparison is made in order to evaluate the improvements. This comparison is made by calculating some common measures about the end effectors’ trajectories (jerk and path lengths) and complemented by the Fréchet Gesture Distance (FGD) that aims to measure the fidelity of the generated gestures with respect to the provided ones. Results show that the described system is able to learn natural gestures just by observation and improves the one developed with a simpler motion capture system. The quantitative results are sustained by questionnaire based human evaluation.

Assessing the Ergonomic Benefits of a New Adjustable Forklift Backrest

2020 ◽  
Vol 64 (1) ◽  
pp. 976-980
Author(s):  
Pranav Madhav Kuber ◽  
Ehsan Rashedi
Keyword(s):  
Comparative Study ◽  
Motion Capture ◽  
Center Of Pressure ◽  
Body Movement ◽  
Pressure Change ◽  
Motion Capture System ◽  
Design Features ◽  
Wide Range ◽  
Body Sizes ◽  
The Mean

A new forklift backrest has been developed by incorporating adjustability concepts into the design to facilitate comfort to a wide range of users. We have conducted a comparative study between the new and original backrests to assess the effectiveness of design features. Using the phenomenon of restlessness, discomfort of the user was associated with the amount of body movement, where we have used a motion- capture system and a force platform to quantify the individuals’ movement for a wide range of body sizes. Meanwhile, subjective comfort and design feedback were collected using a questionnaire. Our results showed a reduction in the mean torso movement and the maximum center of pressure change of location by 300 and 6 mm, respectively, for the new design. Taking advantage of adjustability feature, the new backrest design exhibited enhanced comfort for longer durations and reduced magnitude of discomfort for a wide range of participants’ body sizes.

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