AR0330 Datasheet, PDF (59/77 Pages) ON Semiconductor – CMOS Digital Image Sensor

AR0330: 1/3-Inch CMOS Digital Image Sensor
Compression
Compression
The sensor can optionally compress 12-bit data to 10-bit using A-law compression. The
compression is applied after the data pedestal has been added to the data. See Figure 1:
“Block Diagram,” on page 6.
The A-law compression is disabled by default and can be enabled by setting R0x31D0
from “0” to “1”.
Table 40: A-Law Compression Table for 12-10 bits
Input Range
0 to 127
128 to 255
256 to 511
512 to 1023
1024 to 2047
2048 to 4095
11 10 9
00 0
00 0
00 0
00 1
01 a
1a b
Input Values
Compressed Codeword
8 7 6 54 3 21 0 9 8 7654 3 2
0 0 a b c d e f g 0 0 0ab c d e
0 1 a b c d e f g 0 0 1ab c d e
1 a b c d e f g X 0 1 0ab c d e
a b c de f gX X 0 1 1ab c d e
b c d e f g hX X 1 0 abc d e f
c d e f g h XX X 1 1 a bc d e f
10
fg
fg
fg
fg
gh
gh
Test Patterns
Solid Color
Vertical Color Bars
The AR0330 has the capability of injecting a number of test patterns into the top of the
datapath to debug the digital logic. With one of the test patterns activated, any of the
datapath functions can be enabled to exercise it in a deterministic fashion. Test patterns
are selected by Test_Pattern_Mode register (R0x3070). Only one of the test patterns can
be enabled at a given point in time by setting the Test_Pattern_Mode register according
to Table 41. When test patterns are enabled the active area will receive the value speci-
fied by the selected test pattern and the dark pixels will receive the value in Test_Pat-
tern_Green (R0x3074 and R0x3078) for green pixels, Test_Pattern_Blue (R0x3076) for
blue pixels, and Test_Pattern_Red (R0x3072) for red pixels.
Table 41: Test Pattern Modes
Test_Pattern_Mode
0
1
2
3
256
Test Pattern Output
No test pattern (normal operation)
Solid Color
100% Vertical Color Bars
Fade-to-Gray Vertical Color Bars
Walking 1s test pattern (12-bit)
When the color field mode is selected, the value for each pixel is determined by its color.
Green pixels will receive the value in Test_Pattern_Green, red pixels will receive the value
in Test_Pattern_Red, and blue pixels will receive the value in Test_Pattern_Blue.
When the vertical color bars mode is selected, a typical color bar pattern will be sent
through the digital pipeline.
AR0330_DS Rev. U Pub. 4/15 EN
59
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