Overview

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 high quality 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.

Features

• Number of pixels processed:

2700 pixels × 3 lines

(Both bright and dark correction applied to all pixels)

5400 pixels × 3 lines

(Only bright correction applied to all pixels)

• Processing speed:

1,200 ns/pixel maximum (3-color CCD) (When CLKIN is 20 MHz)

400 ns/pixel maximum (CIS and black-and-white CCD) (When CLKIN is 20 MHz)

• 8-bit A/D converter

(Includes a sensor signal timing adjustment function.)

• 6-bit D/A converter for setting the A/D converter reference potential

• Sensor drive circuit

(Supports all types of CCD and CIS sensors)

• Digital CDS (Correlated double sampling)

• Digital clamp circuit

(Single-point clamping, even field clamping)

• Shading correction

(Bright correction: all-pixel correction, dark correction:

either all-pixel correction or set dark correction attenuation data)

• Gamma correction

(Supports user-defined curves for each of R, G, and B using 8-bit data)

• Color balance (Gain control)

• Main scan direction multi-value resolution conversion

(From 2/1 to 1/2, in units of 1/256)

• Binary coding

(Simple binary coding (slicing), and 64-level error diffusion)

*: The green signal is converted to a binary signal.

• Memory manager

(Image data buffer memory controller)

• Fabricated in a CMOS process for 5-V single-voltage power supply operation.