Method for acquiring weighted gradient quality map for two-dimensional phase unwrapping

Abstract

The invention discloses a method for acquiring a weighted gradient quality map for two-dimensional phase unwrapping, which comprises the following steps of: selecting a template with an appropriate size by taking the current processing point of a wrapped phase diagram as a center; determining gradient weights in an x direction and a y direction in the template; determining weighted gradients in the x direction and the y direction of the processing point according to a calculated value of a pixel corresponding point in a neighborhood of the weighted template and the current processing point; traversing the wrapped phase diagram to obtain weighted gradient maps in the x direction and the y direction; and finally, selecting an appropriate quality function to construct the weighted gradient quality map according to weighted gradient quality values in the x direction and the y direction of pixel points at each processing point and in the neighborhood of the each processing point. The quality map constructed by the method can be directly derived by the wrapped phase diagram, can be used for constructing or improving all gradient-based quality maps, overcomes the defects of original gradient-based quality maps, can effectively avoid influences caused by factors of actual phase discontinuity, noises, shadows, under-sampling and the like, and has a very good application effect during phase unwrapping.

Description

Weighted Gradient Quality Map Acquisition Method for 2D Phase Unwrapping technical field The invention relates to the field of image processing, and is used in image processing to carry out a two-dimensional phase unwrapping algorithm for phase unwrapping a wrapped phase map wrapped in the principal value interval of [-π, π), which can be applied to path tracking method and minimum norm The phase unwrapping method such as the method is a weighted gradient mass map acquisition method for two-dimensional phase unwrapping. Background technique The phase unwrapping problem exists in many research and application fields involving coherent wave processing, such as optical interferometric surface topography, interferometric synthetic aperture radar, medical magnetic resonance imaging, and adaptive optics. In these fields, the surface topography information of the research object has a definite proportional relationship with the continuous phase distribution on the two-dimensional...

AI Technical Summary

Problems solved by technology

The original gradient processing method usually used at present, its phase gradient is the difference between the phase value of the current pixel and the phase of adjacent pixels in the horizontal or vertical direction, which cannot reflect the gradient information in the larger neighborhood of the current pixel. When there is a phase discontinuity, In the case of noise, undersampling, etc., it is difficult to accurately reflect the phase gradient characteristics of the wrapped phase map, and the generated quality map is unreliable, which will lead to phase unwrapping errors

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