IMAGE PROCESSING METHOD, IMAGE PROCESSING DEVICE, IMAGE PROCESSING PROGRAM, AND STORAGE MEDIUM STORING IT

PROBLEM TO BE SOLVED: To provide an image processing method, an image processing device, an image processing program, and a storage medium storing the image processing program capable of detecting a central position of a circle displayed by image data with high precision. SOLUTION: In a step S1, edge intensity of a target pixel is calculated. In a step S2, the edge intensity is compared with a threshold value. In a step S3, an edge direction θ is calculated. In a step S4, it is determined whether a circle as a detection object is a black circle or not. If the circle is a black circle, the edge direction is reversed in a step S5. In a step S6, a circle center candidate area is decided based on the edge direction of the target pixel determined as a pixel on the circumference, and voting to the pixel inside the candidate area is carried out. In a step S7, processing is finished for all the pixels, processing goes to a step S8. In the step S8, a pixel obtaining the highest number of votes is decided as a temporary center pixel. In a step S9, surrounding pixels around the temporary center pixel are decided as center surrounding pixels, and the gravity center coordinate of the temporary center pixel and the center surrounding pixels is decided as the center coordinate of the circle. COPYRIGHT: (C)2006,JPO&NCIPI