CHEETAH Hardware User’s Manual
Imperx, Inc.
Rev 1.7
6421 Congress Ave.
8/26/2016
Boca Raton, FL 33487
+1 (561) 989-0006
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C3880 Frame
Rates (fps)
8-bit, CL
10-tap
Full Resolution
74
1920 x 1080
388
1280 x 720
689
640 x 480
1009
Table 19:
C3880 Maximum Frame Rate for various AOIs
2.4 SUBSAMPLING
2.4.1 Pixel Averaging
The principal objective of the averaging function is to reduce the image resolution
with better final image quality than a sub-sampling function. Sub-sampling as
opposed to averaging has the advantage of increasing the output frame rate by
reducing the number of rows readout, but also introduces aliasing in the final image.
Pixel averaging reduces the output resolution by averaging several pixels together
and has the advantage of reducing aliasing
and
reducing noise increasing SNR.
Subsampling, however, increases output frame rate more than pixel averaging
It is
not
possible to apply both averaging and sub-sampling decimation
simultaneously. Zero ROT is not supported when averaging is enabled. Color
cameras do not support pixel averaging.
The graphic below illustrates the concept of 4:1 averaging for a monochrome image sensor.
The values of pixels P1, P2, P3 and P4 are summed together and the result is divided by 4 to
achieve an average of the 4 adjacent pixels.
Figure 13:
Monochrome pixel averaging
The averaging feature can be used on the full resolution image or within any area of interest.
If, for example, the area of interest is defined to be quad full HD (3840 x 2160) and 4:1
averaging is selected, the output is 1080P (1920 x 1080)