US Patent 7466453 Image processing apparatus

An edge area is detected from an image as a first characteristic. It is possible that the first characteristic can not be detected. An edge is detected from the image as a second characteristic. The second characteristic is expanded. When the first characteristic is detected, the first characteristic is set as a third characteristic. When the first characteristic is can not be detected, the second characteristic is set as the third characteristic. Processing such as ink generating/under-color removing or intermediate tone processing or gamma correction is performed based on the third characteristic.