Image processing apparatus

Abstract

In an image processing apparatus, images on an original document captured by an image capturing device are classified into a binary image and a gradation image, and the densities of the images are then converted using density conversion curves, which are provided for binary images and gradation images, to output an image signal representing converted images. The state of a certain pixel is judged and is classified as one of a plurality of states between binary images and gradation images. Based on the results of the judgment, one curve is selected from a first density conversion curve for binary images, a second density conversion curve for gradation images and at least one third density conversion curve which interpolates the first and second density conversion curves. The density of the certain pixel is converted using the selected curve. The image processing apparatus can provide a high contrast in a binary image area of an original document and maintain the gradation of an image in a gradation image area of the original document. Also, the apparatus can output an image density signal which does not cause an unnatural vision due to an abrupt change in density.