| 摘要 |
PURPOSE:To enable an adequate binary threshold value to be automatically set by a method wherein a control means which samples the brightness of image data and determines a binary threshold value referring to the memory table previously set basing on the the maximum brightness and the minimum brightness obtained is provided. CONSTITUTION:Image data picked up through a TLC (touchless centering) camera 9 are turned into multivalued digits, and the brightness data at a prescribed point in the image sensing region of the camera 9 is sampled. Then, the most adequate binary threshold value is determined basing on the maximum digital value (brightest point) and the minimum digital value (darkest point) of the obtained brightness data. For this processing, a memory table which previously stores the most adequate threshold value correspondent to the maximum and the minimum brightness is provided in a ROM of an image processing device 20. Therefore, the most adequate threshold value correspondent to the maximum and the minimum brightness can be obtained by referring to the memory table. |
