INFORMATION PROCESSOR, DETERMINATION METHOD OF THRESHOLD FOR BINARIZATION, AND PROGRAM

摘要

PROBLEM TO BE SOLVED: To suppress influence of a concentration gradient in any direction caused by a shadow on character recognition.SOLUTION: An information processor 10 includes: a storage unit 11 for storing an image P0 as a binarization object; and a calculation unit 12. The calculation unit 12 calculates the luminance gradient in a shadow region RS on the basis of the luminances of a plurality of first pixel strings R11 and R12 set in a first region having no character, of the shadow region RS in the image P0, corrects the luminance in a second region RC having a character, of the shadow region RS, so as to cancel the luminance gradient, and determines a threshold Th used for binarization of the image P0 on the basis of the luminance distribution in the second region RC after the correction.