Overview

The LC82101 converts an analog image signal from a CCD or contact sensor to high-quality binary image data. The LC82101 uses an internal 8-bit A/D converter for A/D conversion, and in addition to the orthodox dithering technique, also supports an error diffusion technique that allows an even higher quality image to be acquired. These techniques apply to the whole range of processing supported by the LC82101, including full-pixel distortion correction, gamma conversion for arbitrary gamma curves, image compression processing, two-dimensional filtering, halftone processing, and image separation processing to separate documents into text, photograph, and halftone regions. Thus this LSI implements the image processing required by FAX, copier, and OCR systems.

特性 Features

? Number of pixels processed

2048 pixels/line (64 KB memory, white correction only)

4096 pixels/line (256 KB memory, both white and black correction)

8192 pixels/line (256 KB memory, white correction only)

? Processing speed 500 ns/pixel maximum (The processing time for 1 pixel is 16/SYSCLK.)

? Supports medium speed products with a single external memory chip 100 ns access time memory allows 800 ns/pixel processing, and 60 ns access time memory allows 500 ns/pixel processing.

? AGC (The A/D converter high-level reference voltage is varied from 1.2 to 4.2 V in 0.2 V steps.)

? Built-in 8-bit A/D converter (includes a sensor signal delay adjustment function)

? Sensor drive circuit (supports CCD and all CIS types)

? Digital clamp (single-point clamp, even/odd clamp)

? Distortion correction (white correction, black correction, full-pixel correction)

? Gamma correction (supports user-defined curves)

? Image area separation (text, photographs, halftone)

? Simple binary-conversion processing (fixed threshold level, density-adaptive threshold level)

? Halftone processing Structural dithering (64 levels), settable dithering threshold level Error diffusion technique (64 levels)

? Image reduction (thinning, fine black line retaining, fine white line retaining)

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