Automatic setting method of luminance frequency distribution reference value in finger / palm collection and finger / palm collection device using it

摘要

PPROBLEM TO BE SOLVED: To provide an automatic setting method for a luminance frequency distribution reference value to be used for automatic density control of a finger/palm print collection image. PSOLUTION: Processing for obtaining a plurality of finger/palm print images M(I) (I: 1-n) while setting temporary luminance frequency distribution reference values S(I) (I: 1-n) to successively increase the values, processing for finding average luminance for each finger/palm print image M(I) and comparing it with a preset average luminance reference value, and processing for finding a number of pixels P(I) within a fixed range before and after a peak of the luminance frequency in a finger/palm print image portion for each finger/palm print image M(I) as the total number of pixels having luminance included within a fixed range before and after the peak are repeated until the average luminance becomes lower than the average luminance reference value. Then, a number of pixels P(x) within a fixed range before and after the maximum peak is extracted from the number of pixels P(I) within the fixed range before and after the peak, and a temporary luminance frequency distribution reference value S(x) corresponding to the number of pixels P(x) within the fixed range before and after the maximum peak is automatically set as a luminance frequency distribution reference value. PCOPYRIGHT: (C)2004,JPO