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

Sensors ◽  
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.

Using a saddle-assistive device equipped with mechanical orthosis for walking of the person with incomplete spinal cord injury

2021 ◽  
pp. 095441192110201
Author(s):  
Akbar Hojjati Najafabadi ◽  
Saeid Amini ◽  
Farzam Farahmand
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Reaction Force ◽  
Assistive Devices ◽  
Assistive Device ◽  
Walking Ability ◽  
Vertical Force ◽  
Incomplete Spinal Cord Injury ◽  
Combined Application ◽  
Cord Injury

The majority of the people with incomplete spinal cord injury lose their walking ability, due to the weakness of their muscle motors in providing torque. As a result, developing assistive devices to improve their conditionis of great importance. In this study, a combined application of the saddle-assistive device (S-AD) and mechanical medial linkage or thosis was evaluated to improve the walking ability in patients with spinal cord injury in the gait laboratory. This mobile assistive device is called the saddle-assistive device equipped with medial linkage or thosis (S-ADEM). In this device, a mechanical orthosis was used in a wheeled walker as previously done in the literature. Initially, for evaluation of the proposed assistive device, the experimental results related to the forces and torques exerted on the feet and upper limbs of a person with the incomplete Spinal Cord Injury (SCI) during walking usingthe standard walker were compared with an those obtained from using the S-ADEM on an able-bodied subject. It was found that using this combination of assistive devices decreases the vertical force and torque on the foot at the time of walking by 53% and 48%, respectively compared to a standard walker. Moreover, the hand-reaction force on the upper limb was negligible instanding and walking positions usingthe introduced device. The findings of this study revealed that the walking ability of the patients with incomplete SCI was improved using the proposed device, which is due to the bodyweight support and the motion technology used in it.

scholarly journals A flexible ultrasensitive optoelectronic sensor array for neuromorphic vision systems

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.

scholarly journals Identical Limb Dynamics for Unilateral Impairments through Biomechanical Equivalence

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 705
Author(s):  
Fatemeh Rasouli ◽  
Kyle B. Reed
Keyword(s):  
Mathematical Model ◽  
Numerical Solution ◽  
Dynamic Models ◽  
Assistive Devices ◽  
Assistive Device ◽  
Human Walking ◽  
Physical Parameters ◽  
Gait Rehabilitation ◽  
And Performance ◽  
Two Sides

Dynamic models, such as double pendulums, can generate similar dynamics as human limbs. They are versatile tools for simulating and analyzing the human walking cycle and performance under various conditions. They include multiple links, hinges, and masses that represent physical parameters of a limb or an assistive device. This study develops a mathematical model of dissimilar double pendulums that mimics human walking with unilateral gait impairment and establishes identical dynamics between asymmetric limbs. It introduces new coefficients that create biomechanical equivalence between two sides of an asymmetric gait. The numerical solution demonstrates that dissimilar double pendulums can have symmetric kinematic and kinetic outcomes. Parallel solutions with different physical parameters but similar biomechanical coefficients enable interchangeable designs that could be incorporated into gait rehabilitation treatments or alternative prosthetic and ambulatory assistive devices.

Real time fall detection using infrared cameras and reflective tapes under day/night luminance

2021 ◽  
pp. 1-16
Author(s):  
E. Ramanujam ◽  
S. Padmavathi
Keyword(s):  
Low Cost ◽  
Age Groups ◽  
Orientation Angle ◽  
Fall Detection ◽  
Living Environment ◽  
Vision Systems ◽  
Ir Camera ◽  
Cluttered Environments ◽  
Infrared Cameras ◽  
Time Fall

Falls are the leading cause of injuries and death in elderly individuals who live alone at home. The core service of assistive living technology is to monitor elders’ activities through wearable devices, ambient sensors, and vision systems. Vision systems are among the best solutions, as their implementation and maintenance costs are the lowest. However, current vision systems are limited in their ability to handle cluttered environments, occlusion, illumination changes throughout the day, and monitoring without illumination. To overcome these issues, this paper proposes a 24/7 monitoring system for elders that uses retroreflective tape fabricated as part of conventional clothing, monitored through low-cost infrared (IR) cameras fixed in the living environment. IR camera records video even when there are changes in illumination or zero luminance. For classification among clutter and occlusion, the tape is considered as a blob instead of a human silhouette; the orientation angle, fitted through ellipse modeling, of the blob in each frame allows classification that detects falls without pretrained data. System performance was tested using subjects in various age groups and “fall” or “non-fall” were detected with 99.01% accuracy.

Application of Sit-To-Stand Assistive Device Based on Hip Support

2021 ◽  
Vol 14 ◽  
Author(s):  
Huaiqiang Zhang ◽  
Qiang Xue ◽  
Shuo Yang ◽  
Tongtong Wang ◽  
Binwei Zhou
Keyword(s):  
Lower Limb ◽  
Independent Living ◽  
Structural Characteristics ◽  
Assistive Devices ◽  
Assistive Device ◽  
Technology Application ◽  
Assist Devices ◽  
Advantages And Disadvantages ◽  
Sit To Stand

Background: Completing the transition from a sitting position to a standing position is a basic skill in people’s daily lives and is crucial for independent living. Lower limb dysfunction will bring many inconveniences into a person’s life and greatly affect their quality of life. Patients with lower limb dysfunction are a specialized group, and nursing problems for this group are becoming increasingly serious. Helping patients with lower limb dysfunction restore their lower limb mobility or assisting them to walk is a social problem necessary to be solved. Objective: : To review the recent sit-to-stand assistive devices based on hip support, classify them systematically and introduce their characteristics, including the mechanisms and the types of patients for which such mechanisms are applicable; to help patients with lower limb dysfunction or doctors (therapists) understand and choose a reasonable sit-to-stand assist device based on hip support. Methods: This paper summarizes literatures and patents about sit-to-stand assistive devices. From the aspects of structural characteristics, drive type and support modes based on the hip and applications situation, the advantages and disadvantages of the typical sit-to-stand assist devices are represented. Results: Current and future development trends on the structural characteristics, drive type and support modes based on the hip and applications situation of sit-to-stand assist devices are discussed to improve the humanization, modularization and applicability of sit-to-stand assist devices. Conclusion: Sit-to-stand assistive devices based on hip support can help patients improve the quality of their life, assist patients carrying out rehabilitation training, and delay the decline of lower limb function. However, the existing sit-to-stand assistive devices based on hip support need further improvement in the aspects of motion mechanism, new technology application and ergonomics design.

scholarly journals Foot and Ankle Patients Prefer a Hands-Free Single Crutch Compared to Standard Axillary Crutches

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0049
Author(s):  
Alicia Unangst ◽  
Kevin Martin ◽  
Anthony Mustovich ◽  
Jaime Chisholm
Keyword(s):  
Heart Rate ◽  
Free Group ◽  
Perceived Exertion ◽  
Demographic Data ◽  
Physical Exertion ◽  
Assistive Devices ◽  
Rating Of Perceived Exertion ◽  
Assistive Device ◽  
Foot And Ankle ◽  
6 Minute Walk Test

Category: Ankle Introduction/Purpose: Following lower extremity surgery patients are often required to utilize assistive devices in order to perform activities of daily living. As technology and assistive devices continue to improve, providers are faced with selecting a device that is safe while providing high patient satisfaction and a quick return to actives. The purpose of the current study was to compare physical exertion and subject preference between a hands-free single crutch and standard axillary crutches in foot and ankle patients. Methods: A prospective, randomized crossover study was performed using 35 orthopedic foot and ankle patients from within one treatment facility. Each participant had demographic data and heart rate recorded. The patients were then randomized to an assistive device. All participants completed a 6-minute walk test (6MWT); immediately following each 6MWT heart rate, self-selected walking velocity (SSWV), perceived exertion using OMNI Rating of Perceived Exertion (OMNI-RPE) and perceived dyspnea using Modified Borg Dyspnea Scale was obtained. The patients then completed another 6MWT using the other assistive device and was asked the same questions. After completing both 6MWTs participants were asked which assistive device they would prefer to use. Results: A total of 35 patients were included with a median age of 32-year-old. The hands-free crutch was preferred by 86% of participants. Regression analysis was used to test if factors such as gender, height, weight, BMI predicted patient preference of iWalk vs. Crutch. None of these factors were found to be significant. Student t-tests and ANOVAs were performed separately for dyspnea, fatigue ratings, distance (meters) and heart rate between iWalk and crutch all were found to be significant (p<0.05, p=1.13e-11, p=2.29e-13, p=5.21e-05, respectively). The axillary crutch group had higher SSWV (0.8 vs 0.77m/s) but was not found to be significant. Neither group had any falls, however, 58% of axillary participants complained of axillary/hand pain while the hands-free group had 14% complain of proximal strap discomfort. Conclusion: Patients preferred the hands-free crutch while reporting lower perceived dyspnea and fatigue. The hands-free group demonstrated lower physiologic demand, which correlated with patient perception.

Bio-Inspired Techniques in Human-Computer Interface for Control of Assistive Devices

2018 ◽  
pp. 23-46
Author(s):  
P. Geethanjali
Keyword(s):  
Pattern Recognition ◽  
Control Strategy ◽  
External World ◽  
Assistive Devices ◽  
Assistive Device ◽  
Prosthetic Hand ◽  
Orthotic Devices ◽  
Prosthetic Devices ◽  
Navigation Control ◽  
Selection Of

Most of the assistive devices are of user contact based control like body-powered prosthetic hand, joystick control of wheelchair, sip-and-puff, etc. and have a limited number of control movements. The performance of these assistive devices improves using bio-signals/gesture based control embedded in the processor. Gesture based control is widely used in wheelchair navigation control, communication with external world for neuromuscular impaired subjects. On the other hand, bio-signals are used widely in prosthetic devices, wheelchair control, orthotic devices, etc. with pattern recognition based control strategy. The choice and number of features used in pattern recognition for accurate control of assistive device is crucial. Further, these features performance also varies with the classifier. The appropriate selection of combination of pattern recognition will enhance the accuracy. This chapter focuses on bio-inspired techniques in selection of features and classification for the pattern recognition based assistive device control.

Biologically Inspired Components in Embedded Vision Systems

2018 ◽  
pp. 458-493
Author(s):  
Li-Minn Ang ◽  
Kah Phooi Seng ◽  
Christopher Wing Hong Ngau
Keyword(s):  
Vision System ◽  
Low Complexity ◽  
Human Vision ◽  
Primary Concern ◽  
Resource Constrained ◽  
Vision Systems ◽  
Biologically Inspired ◽  
Embedded Vision ◽  
Field Programmable ◽  
Embedded Vision Systems

Biological vision components like visual attention (VA) algorithms aim to mimic the mechanism of the human vision system. Often VA algorithms are complex and require high computational and memory requirements to be realized. In biologically-inspired vision and embedded systems, the computational capacity and memory resources are of a primary concern. This paper presents a discussion for implementing VA algorithms in embedded vision systems in a resource constrained environment. The authors survey various types of VA algorithms and identify potential techniques which can be implemented in embedded vision systems. Then, they propose a low complexity and low memory VA model based on a well-established mainstream VA model. The proposed model addresses critical factors in terms of algorithm complexity, memory requirements, computational speed, and salience prediction performance to ensure the reliability of the VA in a resource constrained environment. Finally a custom softcore microprocessor-based hardware implementation on a Field-Programmable Gate Array (FPGA) is used to verify the implementation feasibility of the presented model.

Three-Dimensional Scene Reconstruction

2011 ◽  
pp. 142-162
Author(s):  
Dimitrios Chrysostomou ◽  
Antonios Gasteratos
Keyword(s):  
Vision System ◽  
Three Dimensional ◽  
3D Models ◽  
Scene Reconstruction ◽  
Depth Information ◽  
Vision Systems ◽  
Working Space ◽  
Scene Structure ◽  
Long Time ◽  
Dimensional Surface

The production of 3D models has been a popular research topic already for a long time, and important progress has been made since the early days. During the last decades, vision systems have established to become the standard and one of the most efficient sensorial assets in industrial and everyday applications. Due to the fact that vision provides several vital attributes, many applications tend to use novel vision systems into domestic, working, industrial, and any other environments. To achieve such goals, a vision system should robustly and effectively reconstruct the 3D surface and the working space. This chapter discusses different methods for capturing the three-dimensional surface of a scene. Geometric approaches to three-dimensional scene reconstruction are generally based on the knowledge of the scene structure from the camera’s internal and external parameters. Another class of methods encompasses the photometric approaches, which evaluate the pixels’ intensity to understand the three-dimensional scene structure. The third and final category of approaches, the so-called real aperture approaches, includes methods that use the physical properties of the visual sensors for image acquisition in order to reproduce the depth information of a scene.

Major Metrics, Concerns, and Assessment Strategy for Mobility Assistive Devices

2020 ◽  
pp. 171-203
Author(s):  
Yiannis Koumpouros
Keyword(s):  
Literature Review ◽  
The Elderly ◽  
Assistive Devices ◽  
Daily Activities ◽  
Assistive Device ◽  
Mobility Devices ◽  
Mobility Aids ◽  
Environmental Causes ◽  
Elderly Mobility

The ageing of the population is one of the major societal and financial problems. The prevalence of disability increases dramatically by age. The loss of mobility can be devastating to the elderly. Mobility aids are a one-way street to maintain independent mobility. The performance of daily activities is restrained by a series of factors related to the assistive device limitations, or the ones emerged from environmental causes. A literature review reveals minimal tools for assessing mobility assistive devices able to capture users' satisfaction. The chapter presents an assessment methodology in order to investigate assistive mobility devices' limitations, dissatisfaction reasons, and identifies the most appropriate tools to study such limitations and conclude in valid outcomes. One of the valuable characteristics of the study presented in its generalizability since it is not disease oriented. A summary of the results from both the literature review and the real case study on a mixed group of end users are presented in the chapter.

Sign in / Sign up

Export Citation Format

Share Document