scholarly journals The effects of ArUco marker velocity and size on motion capture detection and accuracy in the context of human body kinematics analysis

2020 ◽  
pp. 1-10
Author(s):  
Bartosz Wieczorek ◽  
Łukasz Warguła ◽  
Mateusz Kukla ◽  
Arkadiusz Kubacki ◽  
Jan Górecki
Keyword(s):  
Motion Capture ◽  
Relative Error ◽  
Human Body ◽  
Measurement Method ◽  
Expanded Polystyrene ◽  
Measuring System ◽  
Single Plane ◽  
Limit Velocity ◽  
Position Detection ◽  
Correct Representation

The research aim was to analyse the influence of velocity and size of markers on the accuracy of motion capture measurement utilising image processing with the use of OpenCV. On the basis of the obtained results, the usefulness of the applied measurement method in studying the kinematics of the human body while driving operating a wheelchair was determined. This article presents the test results for a low-budget motion capture measurement system for testing the kinematics of the human body in a single plane. The tested measuring system includes a standard activity camera Xiaomi Yi4K, expanded polystyrene markers with printed ArUco codes, and original software for marker position detection developed by the author. The analysis of the measurement method with regard to its applicability in biomechanical studies has highlighted several key factors: the number of measuring points, measurement accuracy expressed as a relative error and the limit velocity at which the marker trajectory is correctly represented. The article shows that the limit velocity of the marker is 2.2 m/s for 50x50 mm markers and 1.4 m/s for 30x30 mm markers. The number of measured points ranged from 233 to 2,457 depending on the marker velocity. The relative error did not exceed 5% for the marker velocities and thus provided a correct representation of its trajectory.

The measuring system for monitoring the microarc heating process during surface hardening of steel products

2021 ◽  
pp. 33-39
Author(s):  
Makar S. Stepanov ◽  
rina G. Koshlyakova
Keyword(s):  
Heat Treatment ◽  
Mathematical Model ◽  
Electric Current ◽  
Measurement Method ◽  
Sample Surface ◽  
Steel Sample ◽  
Measuring System ◽  
Heating Process ◽  
Carbon Powder ◽  
Measured Temperature

The accelerated heat treatment during steel products hardening technology has been investigated. The possibility of measuring the temperature of steel products by thermoelectric platinum-platinum-rhodium thermocouple under microarc heating conditions is analyzed. During the experiments, working junctions of two S-type thermocouples: working and standard, were coined into the sample surface at the same level. The free thermocouples ends were connected to a digital multimeter and a personal computer. It was determined that 5 factors affect the measurement results: the electric current strength in the circuit, carbon powder, calibration, number of repeated measurement cycles, and a thermocouple copy. When planning the experiment, the concept of conducting a step-by-step nested experiment was used. Variance analysis method was used to process the experimental results. The measurement method precision parameters were calculated: repeatability and reproducibility. A linear mathematical model linking the measurement method reproducibility index with the measured temperature value has been obtained. A linear mathematical model is obtained that relates the reproducibility index of the measurement method to the measured temperature value. A measuring system for the experimental determination of the temperature of a steel sample is proposed and its application is justified for different electric current densities on the sample surface and varying duration of microarc heating. The possibilities of selecting and controlling the microarc heating modes depending on the required temperature of the heat treatment of the steel product are determined.

The measurement method of human body bust based on Kinect depth image

2015 ◽  
pp. 231-235
Author(s):  
Y Chong ◽  
Y Wang ◽  
S Pan ◽  
Z Wang ◽  
H Dai ◽  
...  
Keyword(s):  
Human Body ◽  
Measurement Method ◽  
Depth Image

scholarly journals The Influence of Target Properties on the Accuracy of Reflectorless Distance Measurements

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6421
Author(s):  
Joanna Gmitrowicz-Iwan ◽  
Magdalena Myszura ◽  
Tomasz Olenderek ◽  
Sławomir Ligęza ◽  
Heronim Olenderek
Keyword(s):  
Relative Error ◽  
Error Rate ◽  
Laser Scanning ◽  
Distance Measurement ◽  
Expanded Polystyrene ◽  
Low Density ◽  
Distance Measurements ◽  
Colour Type ◽  
Measurement Surface ◽  
Reflecting Surface

Recent years have brought dynamic developments in surveying equipment and techniques. These include reflectorless electromagnetic distance measurement (RL EDM), which is used in a range of devices, especially total stations. Studies concerning the influence of the reflecting surface on the accuracy of RL EDM tend to focus on the colour of the measurement surface, while the influence of the density and thickness of materials is usually neglected. Therefore, this study undertook to examine 53 samples representing various materials of dissimilar features: colour, type of surface and density. The results show that dark and mat surfaces cause higher RL EDM errors than bright, gloss materials. Nonetheless, 76% of the results were in compliance with equipment specifications. Moreover, it was found that the density of the samples had significant impact on the overall accuracy. RL EDM to EPS (expanded polystyrene sheets, low-density material, commonly called Styrofoam) involved a significantly higher error rate. It demonstrates that total station measurements and laser scanning should be performed cautiously, especially with regard to materials of low density (e.g., EPS) and on short distances, where the value of relative error is high.

Study on the Measurement of U-238 Neutron Yield Base on the Fission Chamber

2011 ◽  
Vol 366 ◽  
pp. 474-477
Author(s):  
Ju Mei Ai ◽  
Qiang Wang
Keyword(s):  
Neutron Yield ◽  
Ionization Chamber ◽  
Measurement Method ◽  
Fission Neutron ◽  
Particle Energy ◽  
Measuring System ◽  
Fission Chamber ◽  
Particle Counts ◽  
Yield Monitoring ◽  
Α Particles

This paper discusses a variety of fission neutron yield measurement method, a D-T / D-D neutron yield monitoring of U-238 fission ionization chamber measuring system, the application of spontaneous decay of U-238 α-particles for initial debugging of the system. At different voltage on the α-particle energy spectrum and α particle counts were measured, given the U-238 fission chamber curve to determine the U-238 fission chamber measurement system the best operating parameters.

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