Patent ID: 6985605

Claim:
A phase unwrapping method for fringe image analysis in which a wrapped phase distribution concerning a sample obtained on a predetermined coordinate system according to fringe image data carrying wavefront information of said sample is subjected to unwrapping along a predetermined unwrapping path chosen on said coordinate system, so as to obtain an unwrapped phase distribution, said method comprising: a first step of ranking and storing as a scale for choosing the unwrapping path in a predetermined storage list from an upper rank to a lower rank in the order of size suitable for path selection a predetermined number of numeric data successively calculated so as to respectively correspond to individual paths connecting predetermined pixels adjacent each other on said coordinate system; and a second step of taking out said numeric data at the highest rank in all the numeric data stored in said storage list and choosing the path corresponding to thus taken-out numeric data as a new unwrapping path; wherein the storage of numeric data in said first step comprises a block choosing step of choosing a rank block to store said new numeric data by comparing in terms of magnitude new numeric data to be stored in said storage list with the numeric data at a predetermined representative rank in each of rank blocks for each predetermined rank range in said storage list, and a rank position choosing step of comparing in terms of magnitude said new numeric data with each numeric data in thus chosen rank block so as to determine a rank position at which said new numeric data is to be stored; and wherein said predetermined rank range is updated together with said storage of numeric data in said first step.