The LC82104 converts analog image signals from a CCD and contact image sensor to precise multi-valued image data using a built-in 8-bit A/D converter and internal image-processing functions. The LC82104 includes a 6-bit reference potential setting D/A converter for the 8-bit A/D converter and CDS function, and produces high-quality multi-valued data by performing shading correction for all pixels, color balance adjustment, and gamma conversion with support for arbitrary gamma curves. It also includes a multi-value data resolution conversion function, and thus can support input from and output to systems with different resolutions. Furthermore, it can perform highquality conversion to two-valued images from the green signal. The LC82104 can process up to 5400 pixels by three lines and requires no external memory whatsoever for use in distortion correction and other processing. Thus this IC can implement the image processing required for color scanners, FAX, copiers, OCRs and similar applications.