| 摘要 |
PROBLEM TO BE SOLVED: To more accurately extract a dot image from a photographic image whose histogram of a pixel value does not have two peaks. SOLUTION: A temporary dot is extracted from the photographic image based on a temporary threshold value. A histogram is created for a first window image longer than the temporary dots. A dot is extracted from the photographic image using an intermediate pixel value between pixel values of two peaks as a threshold value when the histogram has two peaks. The histogram for a second window image smaller than the temporary dots, including a part of an outline of the temporary dots is repeatedly created while changing size or a position of the second window image until a two-peak histogram can be obtained when the histogram does not have two peaks. A dot is extracted from the photographic image using an intermediate pixel value between pixel values of two peaks in the obtained two-peak histogram as a threshold value. COPYRIGHT: (C)2011,JPO&INPIT |
