Patent attributes
According to the present disclosure, an image-processing apparatus identifies for each gradation value a connected component of pixels of not less than or not more than the gradation value neighboring and connected to each other in an input image, thereby generating hierarchical structure data of a hierarchical structure including the connected component, extracts based on the hierarchical structure data a connected component satisfying character likelihood as a character-like region, acquires a threshold value of binarization used exclusively for the character-like region, acquires a corrected region where the character-like region is binarized, acquires a background where a gradation value of a pixel included in a region of the input image other than the corrected region is changed to a gradation value for a background, and acquires a binary image data of a binary image composed of the corrected region and the background region.