IMAGE PROCESSING METHOD AND IMAGE PROCESSING APPARATUS FOR EXTRACTING UNEVENNESS PATTERN

PROBLEM TO BE SOLVED: To read an unevenness pattern with high accuracy, even under a longitudinally vibrating condition. SOLUTION: The image processing method for extracting an unevenness pattern from an engraved surface on which an unevenness pattern is engraved and which is vibrating in the irregular direction of the unevenness pattern includes a scanning step of acquiring two-dimensional pattern data having the height data of the unevenness pattern by scanning unidirectionally with respect to the engraved surface; a derivative step of differentiating the two-dimensional pattern data, to determine the degree of change of the height data; a spike removing step of removing one which is steep in the degree of change of the height data out of the two-dimensional pattern data on the basis of the result of the differentiating step; an integrating step of estimating a vibration waveform by integrating the result of the spike removing step; and an unevenness detection step of calculating an engraved waveform corresponding to the unevenness pattern, by subtracting the vibration waveform estimated in the integrating step from the two-dimensional pattern data. COPYRIGHT: (C)2011,JPO&INPIT