| 摘要 |
PURPOSE:To discriminate automatically on whether an image is a dot image or not with high precision by discriminating the fact that the image is the dot image when the rate of black level picture elements when picture elements are sampled at reference intervals is larger than a specific value and the rate of white level picture elements is larger than a specific value. CONSTITUTION:The lateral axis in a figure represents picture elements on one scanning line and the longitudinal axis represents the level of the tentative binary-coding of each picture element by circuits S and D using a single fixed threshold value. The coordinate P=(a+b)/2 of the center picture element of a black-level picture element block B1 is calculated from the coordinate (a) of the starting picture element and coordinate (d) of the ending picture element of said block B1, and the coordinate Q= (c+d)/2 of the center picture element of a block-level picture element of a black-level picture element block B2 is calculated from the coordinate (c) of the starting picture element and coordinate (d) of the ending picture element of said block B2 to calculate the interval D=Q-P between the center picture elements from those P and Q. This D is regarded as a reference interval to sample picture elements at reference intervals from the center picture element (e.g. picture element at coordinate P), calculating the rate of block-level picture elements and the rate of white-level picture elements. |
