AM-800CL / AB-800CL
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8.6. Blemish compensation
The AM-800CL and AB-800CL have a blemish compensation circuit. This function
compensates blemishes on the CCD sensor (typically pixels with extremely high response or
extremely low response). This applies to both monochrome and color versions. Pixels that
fulfill the blemish criteria can be compensated by adjacent pixels on both columns and, in
the case of the AB-800CL, the defective pixels can be compensated by the same Bayer color
pixels in both adjacent columns. The number of pixels that can be compensated is up to 64
pixels per tap, for a total of 256 pixels.
The built-in compensation circuit for the AM-800CL and AB-800CL uses compensation data
collected in the factory and can be turned ON or OFF. The default setting is OFF.
Fig. 39 Blemish compensation
Note: If defective pixels are found consecutively in the horizontal direction, the blemish
compensation circuit does not work.
8.7. LUT (Relative commands LUTC,LUTR,LUYG, LUTB)
This function can be used to convert the input to the desired output characteristics.
The Look Up Table (LUT) has 256 points for setup and each point has an 8-bit gain value. The
output level can be created by multiplying the gain data by the input level.
In the AB-800CL, the same LUT characteristic is applied independent of the color value.
If input data is not in the LUT, the weighted mean average data from upper point and the
lower point are used.
1
256
CCD output
The required characteristics can be achieved by multiplying
LUT parameter and each of 256 points.
Fig.40 LUT concept drawing
B/W
Color
Blemish Compensation Principle
Defective Pixel
