Cheetah Python Cameras User Manual | CoaXPress (CXP) Interface
August 27, 2019
Page
68
of
86
Rev 1.0
EXAMPLES:
1) Desired gain is 7.9x (17.95 dB): [(7.9 – 1.0)*1031]+1024 = 8137.
Set coefficient to 8137.
2) Desired gain is 6 dB, then the code is 2050.
Minimum setting is 1024 corresponding to 1x gain.
Below are other examples:
Gain (dB)
Multiplier
Coefficient
0 dB
1x
1024
3 dB
1.41254x
1449
6 dB
1.99526x
2050
12 dB
3.98107x
4097
Digital Offset
Digital offset is a digital count added or subtracted from each pixel. The range is +/- 512
counts.
Black Level Auto-calibration and Offset
The camera automatically adjusts black level based on measurements of the dark reference
lines at the start of each frame. Imperx recommends leaving the black level auto-calibration
engaged. If auto-calibration is disabled, you can set the Black Level Offset and adjust it by
+/- 511 counts. Black level will vary with temperature and gain settings.
Data Output Format
Pixel Format
The image sensor digitization level is fixed at 10-bits, which enables 8-bit or 10-bit data
format output. With 8-bit output, the camera uses the standard bit reduction process and
truncates the least significant bits.
10-bit digitization
-
If the camera is set to output 10-bit data, sensor data bits map directly to D0 (LSB)
to D9 (MSB).
-
If the camera is set to output 8-bit data, sensor most significant data bits (D2 to
D9) map to D0 (LSB) to D7 (MSB).
MSB
Camera Output – 10 bits
LSB
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
P9
P8
P7
P6
P5
P4
P3
P2
P1
P0
MSB
Camera Output – 8 bits
LSB
D7
D6
D5
D4
D3
D2
D1
D0
-
-
P9
P8
P7
P6
P5
P4
P3
P2
P1
P0
Figure 43:
10-bit internal Digitization with 10-bit and 8-bit outputs