SP-5000M-CXP4 / SP-5000C-CXP4
- 53 -
8.4.1 Linear or Dark Compression
SP-5000-CXP4 has a function which improves the signal to noise ratio in the dark portion of the video.
The default setting is Linear but users can select Dark Compression if it is appropriate for their
application.
Dark Compression 0= Dark compression
1= Linear (Default setting)
Dark Compression
Function
Linear
No compression, Gamma=1.0
Dark Compression
Compress the signal in the dark portion of the video. The S/N is
improved but the linearity might be deteriorated.
8.5. Shading Correction
This function compensates for shading (non-uniformity) caused by the lens or the light source used.
This compensation can be performed even if shading issues are not symmetrical in horizontal and/or
vertical directions.
There are two methods of correction.
Flat shading correction:
The method to compensate the shading is to measure the highest luminance level in the
image and use that data as the reference. Luminance levels of other areas are then
adjusted so that the level of the entire area is equal. Compensation is performed using a
block grid of 20 blocks (H) x 16 blocks (V). Each block contains 128 x 128 pixels. The
complementary process is applied to produce the compensation data with less error.
Fig. 31
Flat shading correction concept drawing
Color shading correction (For SP-5000C-CXP4 only):
In this case, R channel and B channel are adjusted to match with G channel characteristics.
The block grid for compensation is 20 blocks (H) x 16 blocks (V). Each block contains 128 x
128 pixels and the complementary process is applied to produce the compensation data with
less error.
Before adjustment After adjustment
Fig.32 Color shading correction concept drawing
Adjustable range
Less 30%