SP-20000M-PMCL / SP-20000C-PMCL
- 79 -
Fig.38 Concept drawing of Flat shadingcorrection
Color shading correction (For SP-20000C-PMCL only):
In this case, R channel and B channel are adjusted to match with G channel characteristics. The
block for compensation is 20 blocks (H) x 15 blocks (V) and each block contains 256 x 256 pixels.
The complementary process is applied to produce the compensation data with less error.
Before adjustment After adjustment
Fig. 39
Concept drawing of color shading correction
Note: Under the following conditions, the shading correction circuit may not work properly.
If there is some area in the image with a video level less than 70%
If part of the image or the entire image is saturated
If the highest video level in the image is less than 300LSB (at 10-bit output)
8.6 Blemish compensation
The SP-20000-PMCL has a blemish compensation circuit. This function compensates blemishes on
the CMOS 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 averaging the data from pixels in both adjacent columns and, in the case of the
SP-20000C-PMCL, the defective pixels can be compensated by averaging the data from the same
Bayer color pixels in adjacent columns. The number of pixels that can be compensated is up to
1000 pixels.
Fig. 40
Blemish compensation
Adjustable range
Less 30%
B/W
Color
Blemish Compensation Principle
Defective Pixel