Overview

The LC82103 converts the analog video signal from the CCD contact image sensor into high-precision binary image data. The LC82103 includes an 8-bit A/D converter and two 6-bit D/A converters. The 6-bit D/A converters are used for setting reference potential (high and low) of the 8-bit A/D converter. The LC82103 converts the input analog data to high precision multilevel data, that is produced by all pixel shading correction process, multilevel image resolution converting process, and γ correction process of user defined curves. That multilevel data is converted to high-precision bi-level image that is produced by using two dimensional filtering, a image separation method, and an error diffusion technique. Finally the LC82103 is able to reduce the image in the horizontal and vertical directions, too. The LC82103 requires absolutely no external memory since it limits the number of pixels processed to 3072/line. This LSI can implement the image processing used by FAX, copier, and OCR applications.

Features

• Number of pixels processed: 3072 pixels/line

• Processing speed: 250 ns/pixel maximum (When CLKIN = 32 MHz)

• Built-in 8-bit A/D converter (with a sensor signal timing adjustment function)

• Built-in two 6-bit D/A converters for setting the A/D converter high and low reference potential

• Sensor drive circuit (supports CCDs and several CIS types)

• Digital clamping (single-point clamping, even/odd clamping)

• Distortion correction (white correction: all pixels, black correction: settable black correction subtracted data)

• γ correction (support user-defined curves: 8-bit data)

• Image area separation (characters, photographs, screened halftone areas)

• Simple binary coding process (fixed threshold, brightness adaptive threshold)

• Intermediate processing error diffusion (64 levels)

• Multilevel image resolution conversion (1/2, 2/3, 3/2, 2/1)

• Binary image reduction (horizontal: thinning, fine black line retaining, fine white line retaining, vertical: thinning, fine black line retaining)

• Single-voltage 5 V supply and low power due to CMOS process fabrication