Search results for "Motion analysis"

The relationship between the incidence of winners/errors and the time spent in different areas of the court in elite tennis

2013

Martinez-Gallego R, Guzman JF, James N, Ramon-Llin J, Crespo M, Vuckovic G. The relationship between the incidence of winners/errors and the time spent in different areas of the court in elite tennis. J. Hum. Sport Exerc. Vol. 8, No. Proc3, pp. S601-S607, 2013. Winners and errors have been two of the most studied performance indicators in tennis, contributing to the prediction of match outcome and definition of the playing style of the players. Furthermore, the position occupied by the player on the court has also been shown to be a good indicator of both the final result and style of play. The aim of this study was to examine whether there were differences between game winners and losers i…

Test-retest reliability of 3D kinematic gait variables in hip osteoarthritis patients

2011

Import JabRef | WosArea Orthopedics; Rheumatology; International audience; Objectives: (1) to investigate the test-retest reliability of 3D gait analysis (3DGA) in hip Osteoarthritis (OA) patients; (2) to find the minimum number of gait trials needed to overcome intrinsic variability; (3) to check the accuracy of angles measured by the 3D system. Design: 23 Patients suffering from hip OA with no other major disease were recruited. We evaluated the reliability of spatio-temporal variables and body angles (lower-limb joints, trunk and pelvis angles) during two sessions of 3DGA using intra-class correlation coefficients (ICC). The minimum number of trials needed to overcome intrinsic variabili…

Biomechanical Diagnosis and Rehabilitation Control of Pes Equinus Patiens by Computerized Motion Analysis

1985

If a foot is fixed in plantar flexion such as to inhibit a dorsal flexion beyond a rectangular position with reference to the lower leg the resulting syndrome is called pes equinus. These patients exhibit a characteristic gait with stance phases on tiptoe that may amount to a severe handicap for them. The pes equinus is a most common deformity found in patients with a hemiplegic or diplegic disorder in the region of the foot and the lower leg with typical structural changes in the ankle joint and the calf muscles. The therapy of the pes equinus depends on its etiology and its severity. A less severe pes equinus deformity can be treated by physical therapy and other conservative measures. Mo…

Motion analysis using the novelty filter

1991

Abstract An original approach to the motion analysis, based on the novelty filter, is proposed. The novelty filter stresses the novelties occurring in a pattern representing an image of the scene under consideration with respect to patterns representing previous images of the same scene, so that visual information about the motion of the objects is obtained. The novelty filter may be implemented by a neural network architecture, taking advantage of the capabilities of massive parallelism, adaptive learning and noise robustness. The novelty filter may learn the entire trajectory of an object, through an incremental learning of a sequence of images capturing the scene, thus emphasizing if the…

Selective Change Driven Imaging: A Biomimetic Visual Sensing Strategy

2011

Selective Change Driven (SCD) Vision is a biologically inspired strategy for acquiring, transmitting and processing images that significantly speeds up image sensing. SCD vision is based on a new CMOS image sensor which delivers, ordered by the absolute magnitude of its change, the pixels that have changed after the last time they were read out. Moreover, the traditional full frame processing hardware and programming methodology has to be changed, as a part of this biomimetic approach, to a new processing paradigm based on pixel processing in a data flow manner, instead of full frame image processing.

Using deep neural networks for kinematic analysis: Challenges and opportunities

2020

Kinematic analysis is often performed in a lab using optical cameras combined with reflective markers.\ud With the advent of artificial intelligence techniques such as deep neural networks, it is now possible\ud to perform such analyses without markers, making outdoor applications feasible. In this paper I summarise\ud 2D markerless approaches for estimating joint angles, highlighting their strengths and limitations.\ud In computer science, so-called ‘‘pose estimation” algorithms have existed for many years. These methods\ud involve training a neural network to detect features (e.g. anatomical landmarks) using a process called\ud supervised learning, which requires ‘‘training” images to be …

Validity and reliability of a 3-axis accelerometer for measuring weightlifting movements

2016

The purpose of the current study was to assess the validity and reliability of measures obtained by a 3-axis commercial accelerometer during weightlifting movements in comparison with kinematic data derived from the 3D videography. Kinematic data from 3D videography were obtained from 11 track & field throwers performing 3 trials each one at different loads in power snatch, power clean and jerk from the rack. The results showed that the accelerometer measures were highly correlated with derived acceleration data from 3D videography data in the vertical plane (Z axis) taking up to the pull phase (including first pull, transition and second pull) for power snatch and power clean and up t…

Technique detection of cross-country ski classical race using kinematic GNSS

2018

Contribution to a marker-free system for human motion analysis

2002

This paper presents a novel approach to human gait analysis using a marker-free system. The devised acquisition system is composed of three synchronized and calibrated charge coupled device cameras. The aim of this work is to recognize in gray level image sequences the leg of a walking human and to reconstruct it in the three-dimensional space. An articulated threedimensional (3D) model of the human body, based on the use of tapered superquadric curves, is first introduced. A motion-based segmentation, using morphological operators, is then applied to the image sequences in order to extract the boundaries of the leg in motion. A reconstruction process, based on the use of a least median of …

Automatic detection and analysis of cell motility in phase-contrast time-lapse images using a combination of maximally stable extremal regions and Ka…

2013

Phase-contrast illumination is simple and most commonly used microscopic method to observe nonstained living cells. Automatic cell segmentation and motion analysis provide tools to analyze single cell motility in large cell populations. However, the challenge is to find a sophisticated method that is sufficiently accurate to generate reliable results, robust to function under the wide range of illumination conditions encountered in phase-contrast microscopy, and also computationally light for efficient analysis of large number of cells and image frames. To develop better automatic tools for analysis of low magnification phase-contrast images in time-lapse cell migration movies, we investiga…