A Method for Phase Measurement of Object Deformation Using Optical Flow Field

Abstract

The invention discloses a method for measuring the deformation phase of an object by using an optical flow field, which includes the following steps: Step 1: According to the basic assumption of the optical flow field theory, two components u and v of a motion vector between two consecutive images are obtained; Step 2: Extract the horizontal frequency fx0 and the vertical frequency fy0 of the first frame of image stripes by the window Fourier transform method; Step 3: Utilize the two components u and v of the motion vector obtained in the step 1 and the step 2 to obtain The horizontal frequency fx0 and the vertical frequency fy0 of the stripes are calculated to obtain the amount of phase change. The invention only needs to use two fringe images in the space domain to complete the extraction of the deformed phase without converting to the frequency domain and phase unenveloping operations, and is suitable for dynamic measurement, and the effect of phase extraction is better in areas where the fringes are denser. Well, it completely overcomes the disadvantage of large demodulation error when the fringes are too dense in the existing phase demodulation method, and the process is simple and convenient. At the same time, this method also provides a new way for dynamic measurement of optical interference.

Description

technical field [0001] The invention relates to a method for measuring the deformation phase of an object by using an optical flow field. Background technique [0002] Due to its unique advantages, optical interferometry plays a very important role in the measurement of three-dimensional shape and deformation of objects, such as electronic speckle interferometry, holographic interferometry, and moiré interferometry. In these methods, it is necessary to demodulate the phase information of each point in the fringe pattern to realize the deformation measurement, and the methods of demodulating the phase are mainly divided into two categories: time phase measurement method and space phase measurement method. Time-phase measurement methods, such as Temporal Phase-shifting Method (TPM), etc., have the advantages of high displacement measurement accuracy and simple structure, but this type of method requires more fringe patterns and takes a long time. The following is only applica...

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Problems solved by technology

[0004] The object of the present invention is to solve the above problems, and provide a method for measuring the deformation phase of an object by using the optical flow field. Only two fringe images in the spatial domain can be used to complete the extraction of the deformation phase without converting to the frequency domain and Phase unwrapping operation, suitable for dynamic measurement, and the effect of extracting phase is better in the denser fringe area, which completely overcomes the disadvantage of large demodulation error when the fringe is too dense in the existing phase demodulation method

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