Small Displacement Measurement of Crack Opening Using One Pitch Phase Analysis (OPPA) Method

Morimoto, Yoshiharu; Masaya, Akihiro; Yata, Thomas; Luong, Duy Anh; Quarles, Quentin

doi:10.3390/icem18-05407

Cited by 1 publication

(4 citation statements)

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“…There are various phase analysis methods (for example, [ 1 , 11 , 21 , 22 , 23 , 24 , 25 ]). The author also developed the OPPA method [ 9 , 16 , 17 , 18 ]. Here the phase analysis method and the phase-shifting method are described before explaining the OPPA method.…”

Section: Principle Of the Oppa Methodsmentioning

confidence: 99%

“…The authors proposed the one pitch phase analysis (OPPA) method [15][16][17][18] in which phase analysis of the grating pattern is performed with one image.…”

Section: Introductionmentioning

confidence: 99%

“…The principles and application examples of this OPPA method were presented in a paper [17] and proceedings of a few international conferences [15,16,18]. Utilizing the characteristics of the OPPA method, which allows phase analysis of a grating with a single image, it measures the vibration mode of a flat cantilever plate in combination with a high-speed camera [16].…”

Section: Introductionmentioning

confidence: 99%

“…The analysis is performed very easily with high accuracy. Furthermore, it was shown that this OPPA method can also be used for the deformation measurement, and it can also be used for incremental measurement of the crack width for diagnosing the degree of deterioration of infrastructure structures such as bridges [18].…”

Section: Introductionmentioning

confidence: 99%

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

Morimoto

2020

Sensors

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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.

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Section: Principle Of the Oppa Methodsmentioning

confidence: 99%

“…The authors proposed the one pitch phase analysis (OPPA) method [15][16][17][18] in which phase analysis of the grating pattern is performed with one image.…”

Section: Introductionmentioning

confidence: 99%