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9.4.1
Linear and Dark Compression
GO-5000-USB has a dark compression circuit to improve the signal-to-noise ratio in the dark portion
of the image. This function is OFF as factory default setting and can be ON according to
applications.
Dark Compression
Linear(Factory default)
Dark Compression
9.5.
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. Users can store up to 3 shading compensation data in memory.
9.5.1
Shading Correction mode
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.
Adjustable range
Less 30%
Color shading correction (For GO-5000C-USB 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.
GO-5000M-USB / GO-5000C-USB
No compression, Gamma=1.0
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.
Fig. 35 Flat shading correction concept drawing
Function
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