SP-5000M-USB / SP-5000C-USB
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8.4.1 Linear and Dark Compression
SP-5000-USB has a dark compression circuit to improve the signal to noise ratio in the dark
portions of an image.
Dark Compression :
0: Dark Compression
1: Linear (Default)
Dark Compression
Function
Linear(Factory
default)
No compression, Gamma=1.0
Dark Compression
Compress the signal level in the dark portion. It can
improve the signal to noise ratio, but on the other
hand, the linearity will be deteriorated.
The following drawing shows the characteristics of linear and dark compression.
Fig.48 Characteristics
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.
Input
O
ut
put
Linear
Dark
Compression