PAC407BCA/PAC407BCW

CMOS Image Sensor IC

Version 1.7, 13 Sep

2004

PixArt Imaging Inc.

E-mail: fae_service@pixart.com.tw

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3. Function Description

Defect Compensation

The Defect Compensation block can detect the possible defect pixel and replace it with average output of

like-colored pixels from near side of defect pixel. This function can be programmed to enable/disable by

user.

Hardware Windowing

Users are allowed to define window size and window location in PAC407. The location of window can be

anywhere in the sensor array. Window location and size are determined by different register settings.

Sub-Sampling

PAC407 can be programmed to output image in QVGA, QQVGA and CIF size. In QVGA sub-sampling

mode, both vertical and horizontal pixels are sub-sampling at 1/2, while in QQVGA sub-sampling mode,

both vertical and horizontal pixels are sub-sampling at 1/4.

Digital Zoom

By programming Hardware Windowing registers and Sub-sampling registers, PAC407supports 2X and

4X digital zoom.

Automatic White Balance

In digital image applications, color balance is typically achieved by automatic white balance (AWB).

PAC407 can adjust its color spectrum sensitivity to the scene such that the resulting image on the average

has an equal amount of all color components. The AWB mechanism can be set and adjusted by registers.

Color Saturation

If one color is more saturated than others, it will dominate the image. If the colors aren't saturated enough,

the image might appear lifeless. Hence, PAC407 can enable color saturation function by setting registers

to provide a more vivid image for user.

Lens Shading Compensation

In order to compensate the effect of the attenuation due to poorly optic component, PAC407 has a series

of registers to eliminate the shading effect.

Gamma Correction

To realize a more brilliant image quality, PAC407 includes gamma correction function. Gamma correction

performs on the luminance element of the image and allows compensating for non-linear dependence of

the display device output against driving signal (ex. monitor brightness against CRT voltage). Gamma

correction curve is shown as below, and some dedicated registers can adjust it.