A method for character and photograph segmentation using dynamic thresholding

In order to obtain the portability of a book, and reduction of a storage place, it is popular to change a book into a digital book. It has changed into the text data for search of the contents, and data size compression. However, the special character is used for the illustration page or the cover. These characters may be unable to be read as text data by the conventional character recognition. In this study, we focused on that the gradient of brightness value was flat in character area. How to presume a character area from the amount of change of the projection acquired by changing the threshold value of binarization dynamically is described.