An optical system forms an optical image on an imager, and a read control block selects a read rule for the imager depending on a magnification addressed by a magnification address block. The imager transforms an optical image at an addressed area into electrical signals in compliance with the read rule. The read image signals are stored in n image memories, where n is the number of images necessary for ultra-resolution processing. Ultra-resolution processing is built up of a motion estimation block and a high-resolution image estimation block adapted to estimate image data having a high-resolution image sequence. A selector selects a basic image for motion estimation and an image that is estimated in terms of motion.