An Integrated Calibration Technique for Multi-Camera Vision Systems

This paper presents the integration and evaluation of two popular camera calibration techniques for multi-camera vision system development for motion capture. An integrated calibration technique for multi-camera vision systems has been developed. To demonstrate and evaluate this calibration technique, multiple Wii Remotes (Wiimotes) from Nintendo were used to form a vision system to perform 3D motion capture in real time. This integrated technique is a two-step process: it first calibrates the intrinsic parameters of each camera using Zhang’s algorithm [5] and then calibrates the extrinsic parameters of the cameras together using Svoboda’s algorithm [9]. Computer software has been developed for implementation of the integrated technique, and experiments carried out using this technique to perform motion capture with Wiimotes show a significant improvement in the measurement accuracy over the existing calibration techniques.

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A Compact Low Cost Wearable Sensor System for Quantitative Gait Measurement

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.627.212 ◽

2014 ◽

Vol 627 ◽

pp. 212-216

Author(s):

Ming Gui Tan ◽

Cheng Boon Leong ◽

Jee Hou Ho ◽

Hui Ting Goh ◽

Hoon Kiat Ng

Keyword(s):

Gait Analysis ◽

Motion Capture ◽

Vision System ◽

Low Cost ◽

Sensor System ◽

Wearable Sensor ◽

Gait Parameters ◽

Emg Electrodes ◽

3D Motion Capture ◽

Quantitative Gait Analysis

The demand for quantitative gait analysis increases due to increasing number of neurological disorder patients. Conventional gait analysis tools such as 3D motion capture systemsare relatively expensive. Therefore, there is a need to develop a low cost sensor system to obtain the spatial temporal gait parameters without compromising too much on the accuracy. This paper describesthe development of a wearable low cost sensor system which consists ofrelatively less sensing elements with 2 accelerometers, 4 force sensitive resistors (FSR) and 2 EMG electrodes. Thesensor output was validated by a vision system and the relative error was less than 5% formost of the gait parameters measured.

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Gender differences in the Achilles tendon load during the fencing lunge

Baltic Journal of Health and Physical Activity ◽

10.2478/bjha-2014-0018 ◽

2014 ◽

Vol 6 (3) ◽

Cited By ~ 1

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.

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A flexible ultrasensitive optoelectronic sensor array for neuromorphic vision systems

Nature Communications ◽

10.1038/s41467-021-22047-w ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Qian-Bing Zhu ◽

Bo Li ◽

Dan-Dan Yang ◽

Chi Liu ◽

Shun Feng ◽

...

Keyword(s):

Sensor Array ◽

Vision System ◽

Vision Systems ◽

Neuromorphic Circuits ◽

Image Sensing ◽

Perovskite Quantum Dots ◽

Optoelectronic Sensor ◽

Weak Light ◽

Do So ◽

Neuromorphic Vision

AbstractThe challenges of developing neuromorphic vision systems inspired by the human eye come not only from how to recreate the flexibility, sophistication, and adaptability of animal systems, but also how to do so with computational efficiency and elegance. Similar to biological systems, these neuromorphic circuits integrate functions of image sensing, memory and processing into the device, and process continuous analog brightness signal in real-time. High-integration, flexibility and ultra-sensitivity are essential for practical artificial vision systems that attempt to emulate biological processing. Here, we present a flexible optoelectronic sensor array of 1024 pixels using a combination of carbon nanotubes and perovskite quantum dots as active materials for an efficient neuromorphic vision system. The device has an extraordinary sensitivity to light with a responsivity of 5.1 × 107 A/W and a specific detectivity of 2 × 1016 Jones, and demonstrates neuromorphic reinforcement learning by training the sensor array with a weak light pulse of 1 μW/cm2.

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Keypose synthesis from 3D motion capture data by using evolutionary clustering

Concurrency and Computation Practice and Experience ◽

10.1002/cpe.6485 ◽

2021 ◽

Author(s):

Mehmet Akif Günen ◽

Pınar Çivicioğlu Beşdok ◽

Erkan Beşdok

Keyword(s):

Motion Capture ◽

Motion Capture Data ◽

3D Motion ◽

Evolutionary Clustering ◽

3D Motion Capture

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An Electro-Oculogram Based Vision System for Grasp Assistive Devices—A Proof of Concept Study

Sensors ◽

10.3390/s21134515 ◽

2021 ◽

Vol 21 (13) ◽

pp. 4515

Author(s):

Rinku Roy ◽

Manjunatha Mahadevappa ◽

Kianoush Nazarpour

Keyword(s):

Vision System ◽

Extraction Procedure ◽

Orientation Angle ◽

Object Orientation ◽

Assistive Devices ◽

Assistive Device ◽

Vision Systems ◽

Signature Extraction ◽

Voluntary Muscle ◽

Als Patients

Humans typically fixate on objects before moving their arm to grasp the object. Patients with ALS disorder can also select the object with their intact eye movement, but are unable to move their limb due to the loss of voluntary muscle control. Though several research works have already achieved success in generating the correct grasp type from their brain measurement, we are still searching for fine controll over an object with a grasp assistive device (orthosis/exoskeleton/robotic arm). Object orientation and object width are two important parameters for controlling the wrist angle and the grasp aperture of the assistive device to replicate a human-like stable grasp. Vision systems are already evolved to measure the geometrical attributes of the object to control the grasp with a prosthetic hand. However, most of the existing vision systems are integrated with electromyography and require some amount of voluntary muscle movement to control the vision system. Due to that reason, those systems are not beneficial for the users with brain-controlled assistive devices. Here, we implemented a vision system which can be controlled through the human gaze. We measured the vertical and horizontal electrooculogram signals and controlled the pan and tilt of a cap-mounted webcam to keep the object of interest in focus and at the centre of the picture. A simple ‘signature’ extraction procedure was also utilized to reduce the algorithmic complexity and system storage capacity. The developed device has been tested with ten healthy participants. We approximated the object orientation and the size of the object and determined an appropriate wrist orientation angle and the grasp aperture size within 22 ms. The combined accuracy exceeded 75%. The integration of the proposed system with the brain-controlled grasp assistive device and increasing the number of grasps can offer more natural manoeuvring in grasp for ALS patients.

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