| 摘要 |
PURPOSE:To decide the area of each image by a simple constitution by utilizing general properties such as the relatively small density gradient of a light and shade image, the relatively large direction difference in the density gradient of a binary image, and the relatively large gradient and relatively small direction difference in the density gradient of a dot image. CONSTITUTION:In an objective area E, the density gradients are computed in directions a1, a2,..., an predetermined about a picture elements Co that a density gradient arithmetic means 1 aims at the center. An image decision means 2 in case of deciding that the aimed picture element Co belongs to the light and shade image based on the arithmetic result of the arithmetic means 1 holds the decision result, but supplies a picture element which does not belong to the light and shade image to an image deciding means 3. The image deciding means 3 decides which of a binary image and a dot image the picture element Co belongs to based on the directions a1, a2,..., an of the density gradient arithmetic result, and holds the decision result. Further, an area decision means 4 decides the image area of the area E based on the decision frequencies of the light and shade image, binary image, and dot image. |
