| 摘要 |
PROBLEM TO BE SOLVED: To obtain an accurate binarization result at all times even in the case of lighting unevenness and print density unevenness by varying blind zone width adaptively to whether the light and shade range of a signal is large or small. SOLUTION: In this binarization processor 7, a microprocessor 11 performs a binarizing process by using an ROM 13 and an RAM 14 which are connected through a bus 12. The microprocessor 11 when receiving the light and shade signal from an A/D converter 6 finds a section maximum and a section minimum. Then sections of interest are changed in order and near maximums and minimums are found as to all the sections. Then the blind zone width for limiting the range that a threshold value possibly has is calculated. Then the permissible range of the threshold value is found. A lighting unevenness follow-up value is calculated. A maximum variance extent is calculated. Then it is judged whether or not tracking to lighting unevenness is inhibited. In this case, threshold values for binarization are found by one line when blind zone width, near maximums, near minimums, a lighting unevenness follow-up value, and a light and shade signal are given. |
