scholarly journals High-Speed Measurement of Shape and Vibration: Whole-Field Systems for Motion Capture and Vibration Modal Analysis by OPPA Method

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4263
Author(s):  
Yoshiharu Morimoto
Keyword(s):  
Modal Analysis ◽  
Phase Analysis ◽  
Motion Capture ◽  
High Speed ◽  
Phase Distribution ◽  
Conveyor Belt ◽  
Human Motion ◽  
Shape Measurement ◽  
The One ◽  
Vibration Modal

In shape measurement systems using a grating projection method, the phase analysis of a projected grating provides accurate results. The most popular phase analysis method is the phase shifting method, which requires several images for one shape analysis. Therefore, the object must not move during the measurement. The authors previously proposed a new accurate and high-speed shape measurement method, i.e., the one-pitch phase analysis (OPPA) method, which can determine the phase at every point of a single image of an object with a grating projected onto it. In the OPPA optical system, regardless of the distance of the object from the camera, the one-pitch length (number of pixels) on the imaging surface of the camera sensor is always constant. Therefore, brightness data for one pitch at any point of the image can be easily analyzed to determine phase distribution, or shape. This technology will apply to the measurement of objects in motion, including automobiles, robot arms, products on a conveyor belt, and vibrating objects. This paper describes the principle of the OPPA method and example applications for real-time human motion capture and modal analysis of free vibration of a flat cantilever plate after hammering. The results show the usefulness of the OPPA method.

3-D Shape Measurement Based on Optic Interferometric Projection

2010 ◽  
Vol 139-141 ◽  
pp. 1981-1984
Author(s):  
Jiang Hong Gan ◽  
Li Ping Zhou ◽  
Liang Zhou Chen ◽  
Long Xu
Keyword(s):  
High Speed ◽  
Fringe Pattern ◽  
Phase Distribution ◽  
Spherical Wave ◽  
Three Dimensional ◽  
Experimental System ◽  
Shape Measurement ◽  
Small Object ◽  
Dimensional Shape ◽  
The Fourier Transform

This paper aimed to use a novel optic interferometric fringe projection to measure the three-dimensional shape of small object with high resolution. In this method, the projecting fringe pattern, which has a sinusoidal density distribution, good contrast and equal spacing, is generated by a spherical wave incident into a triangle-section prism. Project the fringe onto the subject under test, the image of the deformed fringe pattern modulated by object surface is captured by a high-speed CMOS camera and processed by the Fourier Transform technique to extract the phase distribution which is related to height information. An experimental system is set to conduct 3-D shape measurement and the result shows the validity of the proposed method. The projecting system is simple and compact, which helps to realize the integration and miniaturization of the system.

scholarly journals Measurement of chest wall motion using a motion capture system with the one-pitch phase analysis method

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hiroyuki Tamiya ◽  
Akihisa Mitani ◽  
Hideaki Isago ◽  
Taro Ishimori ◽  
Minako Saito ◽  
...  
Keyword(s):  
Pulmonary Function ◽  
Chest Wall ◽  
Phase Analysis ◽  
Motion Capture ◽  
Vital Capacity ◽  
Wall Motion ◽  
Motion Capture System ◽  
High Precision Measurement ◽  
Chest Wall Motion ◽  
The One

AbstractSpirometry is a standard method for assessing lung function. However, its use is challenging in some patients, and it has limitations such as risk of infection and inability to assess regional chest wall motion. A three-dimensional motion capture system using the one-pitch phase analysis (MCO) method can facilitate high precision measurement of moving objects in real-time in a non-contacting manner. In this study, the MCO method was applied to examine thoraco-abdominal (TA) wall motion for assessing pulmonary function. We recruited 48 male participants, and all underwent spirometry and chest wall motion measurement with the MCO method. A significant positive correlation was observed between the vital capacity (Spearman’s ρ = 0.68, p < 0.0001), forced vital capacity (Spearman’s ρ = 0.62, p < 0.0001), and tidal volume (Spearman’s ρ = 0.61, p < 0.0001) of spirometry and the counterpart parameters of MCO method. Moreover, the MCO method could detect regional rib cage and abdomen compartment contributions and could assess TA asynchrony, indicating almost complete synchronous movement (phase angle for each compartment: − 5.05° to 3.86°). These findings suggest that this technique could examine chest wall motion, and may be effective in analyzing chest wall volume changes and pulmonary function.

scholarly journals Dynamic Measurement of Legs Motion in Sagittal Plane Based on Soft Wearable Sensors

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Yaqing Feng ◽  
Yongze Li ◽  
David McCoul ◽  
Shihao Qin ◽  
Tao Jin ◽  
...  
Keyword(s):  
Motion Capture ◽  
High Speed ◽  
Sagittal Plane ◽  
Wearable Sensors ◽  
Dynamic Measurement ◽  
Human Motion ◽  
Quick Response ◽  
Sample Frequency ◽  
Dynamic Errors ◽  
Joint Motions

Human motion capture is widely used in exoskeleton robots, human-computer interaction, sports analysis, rehabilitation training, and many other fields. However, soft-sensor-based wearable dynamic measurement has not been well achieved. In this paper, the dynamic measurements of legs were investigated by using dielectric elastomers as stain sensors, and an alternating signal was applied to detect the dynamic rotational angles of the legs. To realize a quick response, parameters of the sensors were optimized by circuit analysis. The sensor can detect hip, knee, and ankle joint motions with a sample frequency of 200 Hz. The measurements of the sensors were compared with a commercial motion capture system from PhaseSpace, and dynamic errors between them were smaller than 3° when squatting and walking at low speed and smaller than 5° when walking at high speed. Experiments therefore demonstrate the feasibility of the integrated wearable stretch sensors with pants.

Development of DMD Reflection-Type CCD Camera for Phase Analysis and Shape Measurement

2006 ◽  
Vol 18 (6) ◽  
pp. 728-737 ◽  
Author(s):  
Shien Ri ◽  
◽  
Yasuhiro Matsunaga ◽  
Motoharu Fujigaki ◽  
Toru Matui ◽  
...  
Keyword(s):  
Phase Analysis ◽  
High Speed ◽  
Ccd Camera ◽  
High Accuracy ◽  
Phase Shifting ◽  
Shape Measurement ◽  
Digital Micromirror Device ◽  
Imaging Detector ◽  
Convention Center ◽  
Phase Shifting Method

Phase-shifting method effectively attains high resolution and high accuracy in analyzing phase information on a projected grating. It is difficult to apply dynamically, however, because it usually requires several images. We developed a camera based on digital micromirror device (DMD) technology for high-speed phase analysis and shape measurement, called a DMD reflection-type CCD camera or DMD camera. Implementing DMD technology enables accurate control of intensity reaching the imaging detector of a camera. Moiré is used to adjust pixel-to-pixel correspondence highly accuracy. We introduce a controllable high-speed DMD operation board to control DMD mirrors at high-speed, so each DMD mirror operates as a controllable high-speed shutter for the corresponding CCD pixel. In experiments with an application, we conducted DMD integrated phase-shifting method using correlation to analyze phase distributions of projected gratings from images recorded by the DMD camera. We then discuss principles and experimental results under dynamic conditions. This paper is a revised version of one presented at the SPIE International Symposium on Optomechatronic Technologies (ISOT 2005), December 4-7, 2005 at the Sapporo Convention Center, Japan. That paper appears in SPIE Proceedings Vol.6049, 60490I.

The Modal Analysis of Full Mounted Converter Vessel Tilting Mechaism

2012 ◽  
Vol 430-432 ◽  
pp. 1524-1527 ◽  
Author(s):  
Ying Kui Gu ◽  
Xiang Xiang Tong ◽  
Xin Chong Luo
Keyword(s):  
Modal Analysis ◽  
High Speed ◽  
Natural Vibration ◽  
Three Dimensional ◽  
Normal Operation ◽  
Essential Difference ◽  
Dynamics Modeling ◽  
Three Dimensional Model ◽  
Natural Vibration Mode ◽  
Vibration Modal

To improve the working reliability of the high-speed gears of full mounted converter tilting device and to avoid resonance during working, the dynamics modeling of the high-speed gears is concerned. The three-dimensional model of the high-speed gears is established by using Pro/E, and the vibration modal analysis under definition contact and not definition contact are processed by using Ansys. The natural frequency and natural vibration mode of lower order vibration are obtained by the analysis, and it can be found that there has essential difference between definition contact and not definition contact. This study can provide theory basis for the normal operation of the tilting device.

Dynamic Optimization Design of a Warship’s Gearbox Based on FEM

2011 ◽  
Vol 86 ◽  
pp. 662-665
Author(s):  
Yan Hua Xue ◽  
Xiao Hong Li ◽  
Zhi Guang Wang ◽  
Jie Song
Keyword(s):  
Modal Analysis ◽  
Dynamic Optimization ◽  
High Speed ◽  
Optimization Design ◽  
High Efficiency ◽  
Light Weight ◽  
Heavy Load ◽  
Double Frequency ◽  
Gearbox Vibration ◽  
Vibration Modal

The transmission system of warship’s gearbox is increasingly developing in the direction of high-speed, high-efficiency, heavy-load and light-weight, and the requirements of vibration are increasing as well. The gearbox designed according to static standard often has various problems of instability and vibration which greatly weaken the behaviors of gearbox and influence the invisibility performance of warship seriously. To improve the vibration characteristics of gearbox, vibration modal analysis of a warship’s gearbox is studied based on FEM. In order to avoid resonance in transmission, double-frequency dynamic optimization design of a gearbox is studied and discussed. The method and conclusions can be used as a reference of design of warship’s gearbox.

Predictive Failure Analysis of Solder Joints with Simultaneous High Speed EBSD and EDS

2018 ◽  
Author(s):  
J. Lindsay ◽  
P. Trimby ◽  
J. Goulden ◽  
S. McCracken ◽  
R. Andrews
Keyword(s):  
High Speed ◽  
Solder Joints ◽  
Phase Distribution ◽  
Bond Failure ◽  
Microstructural Parameters ◽  
Snpb Solder ◽  
Grain Orientations ◽  
Accelerated Thermal Cycling ◽  
The Relationship ◽  
Opening Up

Abstract The results presented here show how high-speed simultaneous EBSD and EDS can be used to characterize the essential microstructural parameters in SnPb solder joints with high resolution and precision. Analyses of both intact and failed solder joints have been carried out. Regions of strain localization that are not apparent from the Sn and Pb phase distribution are identified in the intact bond, providing key insights into the mechanism of potential bond failure. In addition, EBSD provides a wealth of quantitative detail such as the relationship between parent Sn grain orientations and Pb coarsening, the morphology and distribution of IMCs on a sub-micron scale and accurate grain size information for all phases within the joint. Such analyses enable a better understanding of the microstructural developments leading up to failure, opening up the possibility of improved accelerated thermal cycling (ATC) testing and better quality control.

scholarly journals Modeling and evaluating beat gestures for social robots

2021 ◽  
Author(s):  
Unai Zabala ◽  
Igor Rodriguez ◽  
José María Martínez-Otzeta ◽  
Elena Lazkano
Keyword(s):  
Motion Capture ◽  
Motion Capture System ◽  
Generative Adversarial Network ◽  
Adversarial Network ◽  
Desirable Feature ◽  
Quantitative Results ◽  
Path Lengths ◽  
End Effectors ◽  
The One ◽  
Made In

AbstractNatural gestures are a desirable feature for a humanoid robot, as they are presumed to elicit a more comfortable interaction in people. With this aim in mind, we present in this paper a system to develop a natural talking gesture generation behavior. A Generative Adversarial Network (GAN) produces novel beat gestures from the data captured from recordings of human talking. The data is obtained without the need for any kind of wearable, as a motion capture system properly estimates the position of the limbs/joints involved in human expressive talking behavior. After testing in a Pepper robot, it is shown that the system is able to generate natural gestures during large talking periods without becoming repetitive. This approach is computationally more demanding than previous work, therefore a comparison is made in order to evaluate the improvements. This comparison is made by calculating some common measures about the end effectors’ trajectories (jerk and path lengths) and complemented by the Fréchet Gesture Distance (FGD) that aims to measure the fidelity of the generated gestures with respect to the provided ones. Results show that the described system is able to learn natural gestures just by observation and improves the one developed with a simpler motion capture system. The quantitative results are sustained by questionnaire based human evaluation.

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