PixArt Imaging Inc.

PAS005B

CMOS Image Sensor IC

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PixArt Imaging Inc.

further alteration to the signal can be applied before the data is output:

2.2 Automatic Background Compensation (ABC)

The ABC function is implemented by 3 steps : ABC-A, Frame-based ABC-D, and Line-based ABC-D. The

ABC-A is implemented in analog domain with an on-chip 9b DAC. The Frame-based ABC-D is implemented

in digital domain to automatically compensate the leakage current with 2 dark reference lines on top of sensor

array. The Line-based ABC-D is implemented in digital domain to automatically compensate the leakage with

4 dark reference columns surround the sensor array. These three blocks can be enable/disable separately by

user.

2.3 Defect Compensation

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

colored pixels on either side of defective pixel. There is no limitation in the capability of defect number. This

function is also enable/disable by user.

2.4 Companding

The companding function is used to simulate the gamma curve and do non-linear transformation before the

data is output. There are 8 curves selected by setting register comp_crv[2:0] as shown in Fig. 2.4. The default

value [00] is a linear curve.