Design, development and evaluation of optical motion‐tracking system based on active white light markers

Stančić, Ivo; Šupuk, Tamara; Panjkota, Ante

doi:10.1049/iet-smt.2012.0157

Cited by 16 publications

(15 citation statements)

References 31 publications

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“…We designed an optical motion-tracking system based on active white light markers [24] and showed that it could be used as an efficient tool for measuring kinematic data on human motion. We also developed a structured light 3D scanner for estimation of human anthropometric parameters [25].…”

Section: Introductionmentioning

confidence: 99%

Design, Development and Testing of a Low-Cost sEMG System and Its Use in Recording Muscle Activity in Human Gait

Šupuk

Skelin

Čić

2014

Sensors

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Surface electromyography (sEMG) is an important measurement technique used in biomechanical, rehabilitation and sport environments. In this article the design, development and testing of a low-cost wearable sEMG system are described. The hardware architecture consists of a two-cascade small-sized bioamplifier with a total gain of 2,000 and band-pass of 3 to 500 Hz. The sampling frequency of the system is 1,000 Hz. Since real measured EMG signals are usually corrupted by various types of noises (motion artifacts, white noise and electromagnetic noise present at 50 Hz and higher harmonics), we have tested several denoising techniques, both on artificial and measured EMG signals. Results showed that a wavelet—based technique implementing Daubechies5 wavelet and soft sqtwolog thresholding is the most appropriate for EMG signals denoising. To test the system performance, EMG activities of six dominant muscles of ten healthy subjects during gait were measured (gluteus maximus, biceps femoris, sartorius, rectus femoris, tibialis anterior and medial gastrocnemius). The obtained EMG envelopes presented against the duration of gait cycle were compared favourably with the EMG data available in the literature, suggesting that the proposed system is suitable for a wide range of applications in biomechanics.

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Section: Introductionmentioning

confidence: 99%

Design, Development and Testing of a Low-Cost sEMG System and Its Use in Recording Muscle Activity in Human Gait

Šupuk

Skelin

Čić

2014

Sensors

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“…One can conclude that the system's depth reconstruction performs with a mean error of 1.5 mm and an RMSE better than 1 cm, which is more than adequate for its intended application. The accuracy of the proposed system could be improved by implementing a sub-pixel point center detection algorithm (Ling, 2005;Stancic, Grujic, 2013), while including more points in the projected pattern would increase the system's final resolution. To summarize, the only difference between the partial and full scans is the number of points projected onto the area, and thus, the resolution of the scan is different.…”

Section: Resultsmentioning

confidence: 99%

A Novel Low-Cost Adaptive Scanner Concept for Mobile Robots

Stančić¹,

Musić²,

Cecić³

2014

ing.inv.

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A fundamental problem in mobile robot applications is the need for accurate knowledge of the position of a vehicle for localizing itself and for avoiding obstacles in its path. In the search for a solution to this problem, researchers and engineers have developed different sensors, systems and techniques. Modern mobile robots relay information obtained from a variety of sensors and sophisticated data fusion algorithms. In this paper, a novel concept for a low-cost adaptive scanner based on a projected light pattern is proposed. The main advantage of the proposed system is its adaptivity, which enables the rapid scanning of the robot's surroundings in search of obstacles and a more detailed scan of a single object to retrieve its surface configuration and perform some limited analyses. This paper addresses the concept behind such a scanner, where a proof-of-concept is achieved using an office DLP projector. During the measurements, the accuracy of the proposed system was tested on obstacles and objects with known configurations. The obtained results are presented and analyzed, and conclusions about the system's performance and possible improvements are discussed.Keywords: Range finder, 3D scanner, mobile robot, structured light, laser, projector. RESUMENEl problema fundamental en las aplicaciones de robots móviles, es la necesidad de conocer con exactitud la posición del vehículo, para poder localizarse en el espacio y evitar obstáculos en su camino. En la búsqueda de una solución, los investigadores e ingenieros han desarrollado diferentes sensores, sistemas y técnicas.Los robots móviles modernos se basan en la información obtenida de diferentes sensores y en sofisticados algoritmos de fusión de datos. Por tal razón, en este artículo se propone un nuevo concepto de escáner de adaptación a bajo costo, basándose en patrones de luz proyectados. La ventaja principal del sistema propuesto es: su adaptabilidad, que permite en los robots el escaneo rápido de los alrededores durante la búsqueda de obstáculos y una exploración más detallada de un objeto determinado, para poder recuperar así, su configuración de la superficie y realizar algunos análisis limitados. El artículo aborda el concepto de un escáner de este tipo, donde se logró la prueba del concepto utilizando un proyector de oficina DLP. Durante las mediciones, la exactitud del sistema propuesto se puso a prueba, usando obstáculos con objetos de configuraciones conocidas. De esta manera, los resultados obtenidos son presentados, analizados y se discuten las conclusiones sobre el desempeño del sistema para generar posibles mejoramientos.Palabras clave: telémetro, escáner 3D, robot móvil, luz estructurada, laser y proyector.

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“…The radius of the marker is 10 pixels, which is 10% of the amplitude of movement. The frame rate is 25 frames/s, and the simulated time of exposure is 1/30 s. The decrease in the amplitude is compared with the theoretical one, assuming a point-like marker described in (12). A sine wave is fitted to the estimated center points with four-parameter sine fitting algorithm [17].…”

Section: A Sinusoidal Movement: Marker Has Finite Dimensionmentioning

confidence: 99%

“…In [12], the Gaussian marker model is used to describe the partial coverage of the pixel by the marker. The intensity distribution is assumed to be…”

Section: ) Fitting Gaussian Marker Modelmentioning

confidence: 99%

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Analysis of the Distortion of Marker-Based Optical Position Measurement as a Function of Exposure Time

Dabóczi

2016

IEEE Trans. Instrum. Meas.

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Marker-based optical position measurement is investigated in this paper. If the exposure time is not very short, it might cause the blur of the marker on the image if fast movement needs to be recorded. This paper investigates the effect of blur on the center point estimate and provides a measure for the distortion to help adjust camera parameters (exposure time, aperture, and ISO sensitivity) in the case of poor lighting conditions. The distortion of the center point estimate is derived as a function of movement of the marker. It is shown that the distortion can be well modeled as integral mean of the marker center. Its distortion can be calculated, and either kept on a limited level by appropriate setting of camera parameters (measure of error is derived) or numerically compensated (inverse filtered). Simulation and measurement examples show the usefulness of the correction.

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Design, development and evaluation of optical motion‐tracking system based on active white light markers

Cited by 16 publications

References 31 publications

Design, Development and Testing of a Low-Cost sEMG System and Its Use in Recording Muscle Activity in Human Gait

Design, Development and Testing of a Low-Cost sEMG System and Its Use in Recording Muscle Activity in Human Gait

A Novel Low-Cost Adaptive Scanner Concept for Mobile Robots

Analysis of the Distortion of Marker-Based Optical Position Measurement as a Function of Exposure Time

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