A Laser Speckle Phase Unwrapping Method Based on Improved Branch Cut Method

Abstract

A laser speckle phase unwrapping method based on the improved branch cutting method, the steps are as follows: 1) input the laser speckle interferometric phase map, and solve all the residual points in the laser speckle interferometric phase map; 2) calculate according to the force formula Find out that each residual point is subjected to the external electromagnetic force, and set the threshold of the electromagnetic force at the same time; 3) Calculate the direction of the light-dark boundary line in the neighborhood where the residual point with the electromagnetic force greater than the threshold is located; 4) Through the above-mentioned light-dark boundary line direction and The relationship between the direction of the electromagnetic force, sequentially "stitching" or "tearing" the neighborhood where the electromagnetic force is greater than the threshold, so that the residual points with opposite electrical properties are continuously approaching or overlapping and disappearing, and the processed laser speckle is generated Interferogram; 5) Repeat steps 1), 2), 3), and 4) until all residual points disappear or the electromagnetic force received is less than or equal to the threshold; 6) Set the branch tangent line according to the existing residual points; 7) The image is unwrapped along the path marked by the branch tangent, and the laser speckle interference phase unwrapping map is obtained.

Description

technical field [0001] The invention belongs to the field of laser speckle interferometry and relates to a laser speckle phase unwrapping method. Background technique [0002] Speckle interferometric phase graph wrapping is a key step in laser speckle measurement. The Goldstein branch-cut method unwrapping algorithm can be used for laser speckle interferometric phase graph wrapping because it can identify residual points, prevent error transmission, and have high unwrapping accuracy. However, when the coherence of the laser speckle interferometry phase image is poor, the signal-to-noise ratio is low, and there are many defective points, it is difficult to accurately set the branch tangent line, the calculation speed is slowed down, and it is easy to form an "island area", resulting in the failure of unwrapping, and the occurrence of drawing and plaque Phenomenon. [0003] There are two commonly used solutions to the above problems: one is to use the branch-cut method in con...

AI Technical Summary

Problems solved by technology

These two types of methods have their own advantages, but they still cannot completely solve the problems of slow unwrapping speed in areas with dense distribution of residual points and easy closure of branch tangent lines, resulting in low success rate of regional expansion errors.

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