Wyniki wyszukiwania - Biblioteka Nauki

1

Models and Algorithms for Human Skeleton Estimation from 3D Marker Trajectories

100%

Janik Ł. , Polański A. , Wojciechowski K.

Machine Graphics and Vision

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2011

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tom Vol. 20, No. 3

333-354

EN

The optical motion capture (MOCAP) technique is very useful in numerous applications in technology, medicine and science. The central problem in the MOCAP technology is skeleton estimation. The quality of skeleton estimation algorithms has the most signifcant infuence on the whole process of MOCAP data processing and analysis. In this paper we describe an original algorithm for skeleton estimation which refines several methodologies available in the literature. We have performed extensive testing and accuracy comparisons of our algorithm compared to some algorithms presented in the literature. We can report that our algorithm enables estimation of a high quality skeleton, with better accuracy than previous methods.

2

Porównanie systemów przestrzennej analizy ruchu na przykładzie systemów optycznych i akcelerometrycznych

85%

Zaborska K. , Jochymczyk-Woźniak K. , Wodarski P. , Bieniek A.

Aktualne Problemy Biomechaniki

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2015

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tom z. 9

129--134

PL

Artykuł prezentuje wyniki porównania dwóch systemów służących do analizy ruchu człowieka- optycznego DTrack2 oraz akcelerometrycznego Xsens. Badania przeprowadzono w Wirtualnej Jaskini (zwanej systemem Cave) znajdującej się w Centrum Nowych Technologii w Gliwicach. Porównania dokonano na podstawie wielkości czasowo - przestrzennych wyznaczonych podczas badań doświadczalnych i obliczonych w programie Matlab. Porównanie danych przedstawiono na podstawie obliczonego błędu średniokwadratowego oraz współczynnika korelacji Pearsona.

EN

The paper presents the results of a comparison of two human motion analysis systems - optical DTrack2 and accelerometric Xsens. The study was conducted in Technopark Virtual Cave (called Cave system) in Gliwice. The comparison was made on the time-space basis, which were designated during the experiment and calculated in Matlab. Comparison of the data was presented on the basis of the calculated mean square error and the Pearson correlation coefficient.

3

Metoda docinania faz ruchu podczas wiosłowania na ergometrze na podstawie danych trójwymiarowych

85%

Kowalczyk K. , Skublewska-Paszkowska M.

Journal of Computer Sciences Institute

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2017

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tom Vol. 5

155--158

PL

W artykule przedstawione zostały metody modyfikacji danych motion capture w formacie C3D oraz analiza modyfikacji danych przy pomocy autorskiej aplikacji. Aplikacja służy do wczytywania plików w formacie C3D z zarejestrowanym ruchem i automatycznego wycięcia powtarzających się, podobnych sekwencji nagranego ruchu. Analizę przeprowadzono pod kątem porównania ze sobą otrzymanych wyciętych faz ruchu. Pod uwagę brane były długości poszczególnych faz, odległości maksymalne i minimalne pomiędzy badanymi markerami oraz porównywane startowe i końcowe klatki ruchu.

EN

The article presents both the methods of data modification of motion capture data in C3D file format, and the analysis of the modification of motion capture data using implemented application. The application is used to load C3D files with recorded motion and to automatic cut of the repeating, similar sequences of recorded motion. The analysis was conducted in terms of comparing received cut phases of motion. Study include cases such as length of particular phases, maximum and minimum distance between examined markers and comparison of start and final motion frames.

4

Algorithms for Computing Indexes of Neurological Gait Abnormalities in Patients after DBS Surgery for Parkinson Disease Based on Motion Capture Data

80%

Stawarz M. , Kwiek S. , Polański A. , Janik Ł. , Boczarska-Jedynak M. , Przybyszewski A. , Wojciechowski K.

Machine Graphics and Vision

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2011

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tom Vol. 20, No. 3

299-317

EN

The motion capture (MOCAP) technology is becoming very useful in medical applications, such as orthopedics, neurology and physical therapy. In the literature the reare already studies of using MOCAP measurements for diagnosis of gait abnormalities. In this paper, we present an algorithm for computation of important indexes defining abnormalities of the gait for a unifed MOCAP data standard, namely for the ASF/AMC MOCAP data recording and storage system. We also present preliminary experimental results on examination of Parkinson’s disease (PD) for a bilateral subthalamic nucleus stimulation patient in the MOCAP laboratory.

5

Analysis of two methods indicating the shoulder joint angles using three dimensional data

80%

Skublewska-Paszkowska M. , Dekundy M. , Lukasik E. , Smolka J.

Physical Activity Review

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2018

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tom 6

37-44

EN

The article contains a comparative analysis of two methods of calculating angles in the shoulder joint of the right upper limb. For the purposes of this study, a marker -vector method was developed that calculates angles based on retroreflective 3D marker’s positions and vectors created on the basis of their positions. Movements from two types of sports (sword fighting and tennis forehand) were analysed. These movem ents were recorded using an optical motion capture system. The obtained results were compared with the values read from the Plug -in Gait biomechanical model from C3D files. The results show that the proposed method is more universal and can be used indepen dently. In addition, the Plug -in Gait model is not adequate for the analysis of the acquired shoulder angles of tennis players.

6

Motion capture as a modern technology for analysing ergometer rowing

80%

Skublewska-Paszkowska M. , Montusiewicz J. , Łukasik E. , Pszczoła-Pasierbiewicz I. , Baran K. R. , Smołka J. , Pueo B.

Advances in Science and Technology. Research Journal

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2016

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tom Vol. 10, nr 29

132--140

EN

The paper presents a purpose-built laboratory stand consisting of a Vicon motion capture system with reference video cameras, wireless EMG system, Concept 2 Indoor Rower ergometer, wireless heart rate monitor and the Nexus software. A pilot study of people who exercise on the ergometer helped to create a proper configuration of all the components of the laboratory. Moreover, a procedure for carrying out research was developed, which consists of several steps divided into 4 stages: preparation of the motion acquisition system; preparation of the participant; familiarising participants with the technique of rowing, recording their movements and acquiring other measurement signals. Preliminary analysis of the results obtained from heterogeneous signals from various devices showed that all the components of the research stand are mutually compatible and the received signals do not interfere with one another.

7

Algorithms for tennis racket analysis based on motion data

80%

Skublewska-Paszkowska M. , Łukasik E. , Smółka J.

Advances in Science and Technology. Research Journal

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2016

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tom Vol. 10, nr 31

255--262

EN

Modern technologies, such as motion capture systems (both optical and markerless), are more and more frequently used for athlete performance analysis due to their great precision. Optical systems based on the retro-reflective markers allow for tracking motion of multiple objects of various types. These systems compute human kinetic and kinematic parameters based on biomechanical models. Tracking additional objects like a tennis racket is also a very important aspect for analysing the player’s technique and precision. The motion data gathered by motion capture systems may be used for analysing various aspects that may not be recognised by the human eye or a video camera. This paper presents algorithms for analysis of a tennis racket motion during two of the most important tennis strokes: forehand and backhand. An optical Vicon system was used for obtaining the motion data which was the input for the algorithms. They indicate: the velocity of a tennis racket’s head and the racket’s handle based on the trajectories of attached markers as well as the racket’s orientation. The algorithms were implemented and tested on the data obtained from a professional trainer who participated in the research and performed a series of ten strikes, separately for: 1) forehand without a ball, 2) backhand without a ball, 3) forehand with a ball and 4) backhand with a ball. The computed parameters are gathered in tables and visualised in a graph.

8

Realistic model of spine geometry in the human skeleton in the VICON system

80%

Długosz M. , Chwała W. , Maciejasz P. , Alda W.

Bio-Algorithms and Med-Systems

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2012

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tom Vol. 8, no. 1

123--132

EN

The human spine is definitively one of the most important parts of a living body. From biomechanical point of view, this organ is the most complicated structure, and a dynamic analysis of its motion still requires more detailed models be created. The aim of this study is to build an accurate computer model of the geometry of the spine and insert it into available skeleton models, used in Vicon. Up to now such models were simplified and that is why they were not sufficient for research of detailed motion of the spine. The paper describes the process of creating models of the vertebrae. During research, authors simultaneously used two techniques: 3D scanning of the vertebrae and computed modeling in 3D graphics software. A universal data format: .obj used to keep the information about surface shape of an object, its colour, texture etc. is presented in detail. In a discussion on Vicon data formats and relations between them, several file types are taken under consideration: marker files: .mkr, global model parameters files: .mp, files of the model structure: .mod. But first of all, step-by-step instructions of how to connect the files with geometrical objects for the visualization purposes, are presented.

9

The influence of different Cardan sequences on three-dimensional cycling kinematics

80%

Sinclair J. , Hebron J. , Hurst H. , Taylor P.

Human Movement

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2013

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tom 14

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nr 4

334-339

EN

Purpose. Three-dimensional (3-D) kinematics are widely utilized to quantify movement in cycling analyses. Three-dimensional angular kinematics are obtained using the Euler/Cardan technique, however, Cardan angles are influenced by their ordered sequence and may affect the resultant angular parameters. An XYZ sequence of rotations is currently recommended, although this technique may not always be appropriate when coronal and transverse plane angles are quantified. This study aimed to determine the influence of the six available Cardan sequences on 3-D lower extremity kinematics during cycling. Methods. Kinematic information was obtained from twelve cyclists using an optoelectronic 3-D motion capture system operating at 250 Hz. Repeated measures ANOVAs were used to compare the kinematic parameters obtained using the six Cardan sequences, and intraclass correlations were employed to detect the presence of crosstalk across planes. Results. The results show that discrete kinematic parameters in the sagittal, coronal and transverse planes were significantly greater when using the YXZ and ZXY sequences. It was also observed that these sequences were associated with the strongest correlations from the sagittal plane and also exhibited evidence of gimbal lock. Conclusions. The results suggest that the accurate representation of 3-D kinematics during cycling should continue utilizing the XYZ sequence and avoid the use of the YXZ and ZXY sequences.

10

Rehabilitation robot prototypes developed by the ITAM Zabrze

71%

Michnik A. , Brandt J. , Szczurek Z. , Bachorz M. , Paszenda Z. , Michnik R. , Jurkojć J. , Rycerski W. , Janota J. , Michnik A. , Brandt J. , Szczurek Z. , Bachorz M. , Paszenda Z. , Michnik R. , Jurkojć J. , Rycerski W. , Janota J.

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11

Determination of the orientation of an object within a 3D space. Implementation and example applications

71%

Różanowski K. , Lewandowski J. , Placha M.

International Journal of Microelectronics and Computer Science

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2015

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tom Vol. 6, nr 4

124--129

EN

The article presents a design of a measurement system implementing algorithms for determination of the orientation of objects within three-dimensional space using am integrated triaxial MEMS system, magnetometer, and Madgwick’s AHRS sensor fusion algorithm. Also included in the proposed implementation are the algorithms for calibration of sensors. Estimated orientation of the object of interest is provided using Euler’s angles or quaternions The system consists of a data acquisition system and software to visualize the acquired data. The main components of the acquisition system include a microcontroller featuring ARM Cortex M4 processor core and integrated 9DOF module consisting of an accelerometer, gyroscope, and magnetometer. The measurement system is capable of communicating with other devices via a Bluetooth interface. The measurements of the monitored values read by 9DOF sensors may be collected at sampling frequencies of up to 100Hz. Options to save data to SD cards and to maintain power supply from a battery are also available. The proposed solution is characterized by low construction costs, small dimensions, and ease of implementation in all types of systems. It can be used for example in mapping the movement of limbs (spatial orientation of the foot, detection of gait cycle phases, assessment of motor activity), as a support tool in inertial navigation systems or in the control of objects in motion (aerial vessels, mechanical vehicles). The article also presents an application of the system as a limb motion capture device.

12

Influence of additional loads on chosen gait parameters and muscles activity

71%

Ludwicki M. , Zagrodny B. , Wojnicz W. , Mrozowski J. , Awrejcewicz J.

Vibrations in Physical Systems

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2016

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tom Vol. 27

227--236

EN

This paper is devoted to human motion analysis and comparison of chosen kinematics parameters during normal gait with and without additional load in a form of backpack. A stability in both cases were compared in both frontal and sagittal planes, by applying a video tracking system. Experimental tests performed on treadmill, passive markers, placed on volunteers bare skin were used. Additionally, an infra-red camera was employed to evaluate muscle activity and its groups involved in the movement. The change of body temperature and distribution of the thermal maps were observed. Analysing these thermograms, loading of different muscle groups was evaluated. During the experiment, an attempt to correlate a results obtained from a thermal imaging camera and video tracking system were made. It is shown that thermal imaging can help to evaluate an asymmetry in muscle load and in some cases can help to detect pathological cases, what was confirmed with motion analysis. Advantages and disadvantages of this method were also described.

13

On the human arm motion camera tracking system

71%

Andrysiak T. , Awrejcewicz J. , Ludwicki M. , Zagrodny B.

Vibrations in Physical Systems

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2012

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tom Vol. 25

41--46

EN

This paper presents results of research devoted to tracking human arm trajectories in sagittal plane by means of motion capture. One camera tracking system was developed. Co-ordinates of upper limb joints (distincted by light reflecting markers) were obtained via tracking software. Markers were illuminated coaxially to the optical axis of the lens to obtain maximum of reflectivity. Positions, linear velocities and accelerations of a shoulder, elbow, wrist and palm in a sagittal plane were presented. Obtained results in the form of points (in Cartesian co-ordinate system) can be adopted for control of mechanism and robots with kinematics similar to that of a human arm. The obtained results show that in studied biological systems there are no fixed trajectories. All movement co-ordinates (including velocities, accelerations and joints angles) are slightly different for each time selected until movement task is completed. Presented method is relatively inexpensive and noninvasive and can be adopted for other types of motion capture.

14

Use of motion capture in assisted of knee ligament injury diagnosis

71%

Bednarski R. , Bielak A.

Journal of Applied Computer Science

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2018

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tom Vol. 26, nr 1

7--32

EN

This study treats of the use of motion capture systems as the help diagnose knee injuries. It consists of the theoretical work and the application. The written work describes a course of research includes choice of research group, selection of appropriate exercises, find useful computational methods, description created for research applications and summary results. The practical part was to create an application for physiotherapists which could help them to diagnosis potential pathology of the knee. The purpose of this study was to test whether a motion capture system dedicated to entertainment can be used in the medical aspect. This system was test for selected methods and determined to be suitable for supporting the diagnosis of knee injuries. Otherwise it has to be written what was the reason of failure. The results of the study were that after trial and error methods peeled action and created application proved helpful.

15

Vertical Breast Displacement in Asian Women During Exercise: influence of Bra Type, Size and Different Parts of the Breast

70%

Sheng X. , Chen X. , Lake M. J.

Fibres & Textiles in Eastern Europe

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2022

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tom Vol. 30, no. 3

1--8

EN

Asian women have smaller breast sizes and greater breast density, which suggests specific research on their breast kinematics and biomechanics. To investigate vertical breast displacement of Asian women among exercise modalities (rope skipping, walking, jogging, running) in different support conditions (wearing everyday bra or sports bra), and assess the motion between different parts of the breast, seven participants were selected to participate in this study. Five infrared markers were placed on each of their left breasts, and a three-dimensional motion capture system (NDI Optotrak Investigator) was used to collect the data on vertical breast displacement during walking (5 km/h), jogging (7.5 km/h), running (10 km/h) and rope skipping (2 Hz). No significant difference was found in the vertical displacement of different parts of the breast in the two bra conditions. Also, there was significant difference in vertical breast displacement among rope skipping, jogging and running. Breast size did not significantly affect its vertical displacement. The smaller, denser breast appears to reach a threshold of vertical displacement that is similar at high severities of dynamic exercises (jogging, running and rope skipping). The results might be useful for designing special sports bras for Asian women with small breasts or rope skipping participants to improve the shock absorption function.

16

Rejestracja ruchu za pomocą urządzenia Microsoft Kinect

60%

Kopniak P.

Pomiary Automatyka Kontrola

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2012

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tom R. 58, nr 11

1016-1018

PL

Artykuł dotyczy tematyki rejestracji ruchu postaci ludzkiej (ang. Motion Capture). Praca pokazuje jak do rejestracji ruchu można wykorzystać kontroler ruchu Microsoft Kinect. Praca zawiera wyniki badań weryfikujących jakość oprogramowania NITE służącego do wyznaczania rotacji członków ciała w stawach. Badania wykazały, że jakość rejestrowanego ruchu nie jest wysoka. Mimo tego uzyskane dane mogą być wykorzystane do analizy gestów lub rozpoznawania ruchu.

EN

This paper refers to a subject of a human body motion capture. Common video based motion capture systems are very expensive. This paper shows that it is possible to use a cheaper solution for motion capture which is a Microsoft Kinect movement controller. There is presented the software for motion capture of a human skeleton. We may use Microsoft SDK programmer toolkit or freeware frameworks like CL NUI Platform, OpenKinect and OpenNI for this purpose. We used OpenNI and NITE libraries (diagram in Fig. 2) for our research. The results of measurements of human joint angles with use of Kinect and our OpenNI based application are given and discussed. These angles are used for recording the movement into motion capture BVH files. We used free application Brekel Kinect (Fig. 3) for this purpose. The recorded data can be used for a realistic animation development. In our case, the data was used as an input source for our own visualization application made in Java language. The quality of recorded motion is not very high due to the calculation delays and problems with appropriate joint localization by the NITE software. The Kinect controller is not suitable for very accurate motion capture, e.g. for the needs of biomedicine, but the captured data are of sufficient quality for research related to the analysis of gestures and remote control.

17

Employment of motion capture to measurement of motion parameters of the lower limb exoskeleton

60%

Kuźmierowski T. , Ostaszewski M.

International Journal of Applied Mechanics and Engineering

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2012

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tom Vol. 17, no. 3

893-898

EN

The article presents a software developed by the authors for data collection using the motion capture technique. Elements placement recording was based on color markers. The measured object was the lower limbs exoskeleton which has been constructed by the authors. The software contains an algorithm of marker location conversion onto angular displacements of each segment forming a rotational kinematic pair. Transducers mounted on the exoskeleton construction that measure direct joint angular displacement were used in order to verify data collected by the software.

18

A method for human gait comparison

60%

Skublewska-Paszkowska M. , Smołka J.

Przegląd Elektrotechniczny

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2014

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tom R. 90, nr 8

30-33

EN

This paper presents a method for comparing two different human gaits recorded in a motion capture laboratory. The comparison consists in comparing how joint angles change. The test data was read from C3D files. In order to obtain presented results a piece of software is created in C++ language. The software allows for reading acquisition files and calculating the angles between chosen body parts.

PL

Artykuł przedstawia metodę porównania dwóch różnych nagrań ruchu człowieka. Porównanie dotyczy wybranych kończyn i polega na badaniu zmienności kątów poszczególnych stawów. Wykorzystano dane o trajektoriach markerów odczytane z plików C3D. Do uzyskania wyników wykorzystano program opracowany w języku C++ służący do odczytywania nagrań i obliczania wspomnianych kątów.

19

Markerless assisted rehabilitation system

60%

Binkowski M. , Guzek K. , Napieralski P.

Journal of Applied Computer Science

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2013

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tom Vol. 21, nr 2

7--19

EN

The project focuses on the use of modern technology to analyze human movement. This analysis turns out to be useful aid for physicians in rehabilitation of patients with limb injuries. This method is more precise than simple observation of the patient through the organ of sight. The proposed system allows markerless determination of deviations between the selected bones and joints, and as a result do not require specialized and expensive equipment. The implemented application presents instructional animation of the exercises and verify the correctness of its performance in real time. The equipment that meets the requirements of the project is the Microsoft Kinect, which is nowadays widely used in the medical ﬁeld.

20

Design and evaluation of a SteamVR tracker for training applications – simulations and measurements

60%

Maciejewski M. , Piszczek M. , Pomianek M. , Pałka N.

Metrology and Measurement Systems

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2020

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tom Vol. 27, nr 4

601--614

EN

Virtual reality (VR) has become a realistic alternative to conventional learning methods in numerous fields including military training. Accurate and precise tracking of a user wearing a head-mounted display is necessary to achieve an immersive VR experience. The widely available SteamVR system, where licensed users can design and construct trackers optimized for a given application can be an alternative to very expensive professional motion tracking. This paper presents the complete design process of a SteamVR tracker dedicated to a shooting simulation in a VR environment. We describe the optimization and simulation of the tracker’s shape and configuration of the sensors. In the simulation phase the developed model had better parameters than its commercial counterparts. Next, the optimized prototype was constructed and configured. The dedicated and automated measuring arrangement provided experimental verification of the tracker’s performance. Tracking performance as well as the accuracy and precision of both position and orientation measurements were determined and compared with simulations, which proved that the simulation software can accurately predict selected properties of the proposed tracker.