| 摘要 |
PROBLEM TO BE SOLVED: To accurately binarize a marking character even in the case where the marking is shallow by binarizing a picture extracted by a white part extracting part and a picture extracted by a black part extracting part and providing a synthesizing part synthesizing them or the like. SOLUTION: An image pickup part 10 for picking up a part of marking and a binarizing part 20 for binarizing a gradation picture imaged by this image pickup part. Then, the depth determination means 22 of the binarizing part 20 determines the depth of the marking based on the gradation picture, and if it is determined that this marking is shallow, the black part extracting means 24 and the white part extracting means 26 extract a black part and a white part using a 1st threshold value α and a 2nd threshold value βrespectively, and then the synthesizing means 28 synthesizes them. Thus, even in the case where the marking is shallow and the black line of the character part is narrow, the marking character can be binarized without loosing the characteristic of the character by extracting the white part and performing synthesizing. |
