MT9P006 Datasheet, PDF (35/47 Pages) ON Semiconductor – CMOS Digital Image Sensor

MT9P006: 1/2.5-Inch 5 Mp Digital Image Sensor
Features
Table 16: ISO Gain Settings
Register Value
ISO Level
ISO 142 (min)
ISO 200
ISO 400
ISO 800
ISO 1600
Register Address
0x35
0x35
0x35
0x35
0x35
(with Col_sum=0)
0x000B
0x0010
0x0020
0x0060
0x0860
(with Col_sum=1)
0x0006
0x0008
0x0010
0x0020
0x0060
Note: The minimum ISO level is ISO 142.
Gain Value
(with
Col_sum=0)
(with Col_sum=1)
1.38
0.75
2.00
1.00
4.00
2.00
8.00
4.00
16.00
8.00
Analog Gain
The analog gain is specified independently for each color channel. There are two
components, the gain and the multiplier. The gain is specified by Green1_Analog_Gain,
Red_Analog_Gain, Blue_Analog_Gain, and Green2_Analog_Gain in steps of 0.125. The
analog multiplier is specified by Green1_Analog_Multiplier, Red_Analog_Multiplier,
Blue_Analog_Multiplier, and Green2_Analog_Multiplier. These combine to form the
analog gain for a given color C as shown in this equation:
AG_C = (1 + C_Analog_Multiplier) × (C_Analog_Gain / 8)
The gain component can range from 0 to 7.875 in steps of 0.125, and the multiplier
component can be either 0 or 1 (resulting in a multiplier of 1 or 2). However, it is best to
keep the "gain" component between 1 and 4 for the best noise performance, and use the
multiplier for gains between 4 and 8.
Digital Gain
Offset
The digital gain is specified independently for each color channel in steps of 0.125. It is
controlled by the register fields Green1_Digital_Gain, Red_Digital_Gain, Blue_Digi-
tal_Gain, and Green2_Digital_Gain. The digital gain for a color C is given by:
DG_C = 1 + (C_Digital_Gain / 8)
The MT9P006 sensor can apply an offset or shift to the image data in a number of ways.
An analog offset can be applied on a color-wise basis to the pixel voltage as it enters the
ADC. This makes it possible to adjust for offset introduced in the pixel sampling and
gain stages to be removed, centering the resulting voltage swing in the ADC's range. This
offset can be automatically determined by the sensor using the automatic black level
calibration (BLC) circuit, or it can be set manually by the user. It is a fairly coarse adjust-
ment, with adjustment step sizes of 4 to 8 LSBs.
Digital offset is also added on a color-wise and line-wise basis to fine tune the black level
of the output image. This offset is based on an average black level taken from each row's
dark columns, and is automatically determined by the digital row-wise black level cali-
bration (RBLC) circuit. If the RBLC circuit is not used, a user defined offset can be
applied instead. This offset has a resolution of 1 LSB.
MT9P006_DS Rev. E Pub. 5/15 EN
35
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