Image processing device and image processing method

Abstract

According to a fine line detection processing, when for a subject pixel to be subjected to the fine line detection processing, a 3×3 matrix area centered on this subject pixel is set as a subject area. Point values '0' to '8' are assigned to the matrix elements constituting this 3×3 matrix subject area. Then, three pixels with the first, second, and third lowest brightness values are extracted from the subject area. When the total point value of the three extracted pixels is equal to “12”, the extracted pixels are determined as being in a connected state. Then, an intermediate value is calculated from the minimum and maximum values of brightness (Y) of pixels in the subject area. When the number of pixels with a brightness (Y) value smaller than the intermediate value is less than 4, the subject pixel is determined as being a fine-line pixel. A fine-line code is added to the subject pixel that is determined as being a fine-line pixel. By the fine line detection processing, even a one-dot fine line, which is difficult to detect during the edge part detection, can be detected with certitude.