Patent ID: 7593596

Claim:
A phase unwrapping method of generating a wrapping phase distribution in which pixels of wrapped phases are two-dimensionally disposed according to an interference fringe image of a measurement object, and determining an unwrapping path connecting pixels of unwrapped phases according to the wrapping phase distribution; the phase unwrapping method characterized by having a candidate pixel generating step of setting a starting pixel or a path-determined latest pixel as a parent pixel, searching a path-undetermined adjacent pixel which is adjacent around the parent pixel, and generating, with respect to the searched adjacent pixel, a candidate pixel having pixel data in which the parent pixel and a weight which is magnitude of a phase difference in which phase skip between the pixels is corrected are combined; a registration control step of, if the weight of the candidate pixel is equal to or more than a predetermined threshold value, registering the pixel to a first data registration unit having a function of ordering the registration order and ordering the pixel based on the weight, and, if it is less than the threshold value, registering the pixel to a second data registration unit not having the function of ordering the registration order; and a path determination step of, every time the process in which all the adjacent pixel around the parent pixel is set as the candidate pixel is finished, retrieving and eliminating one candidate pixel in accordance with the registration order from the second data registration unit if the candidate pixels are present in the first data registration unit and the second data registration unit or if the candidate pixel is present merely in the second data registration unit, retrieving and eliminating the candidate pixel having an ordered minimum weight if the candidate pixel is present merely in the first data registration unit, determining a path between the eliminated candidate pixel and the parent pixel, and passing the eliminated pixel to the candidate pixel generating step as a next parent pixel.