mt9v034c12stmdes aptina, mt9v034c12stmdes Datasheet - Page 61

• Manufacturer Part Number: mt9v034c12stmdes
• Description: 1/3-inch Wide-vga Cmos Digital Image Sensor
• Manufacturer: aptina

Row-wise Noise Correction
Automatic Gain Control and Automatic Exposure Control
PDF: 09005aef8366edcb/Source: 09005aef8366ede5
MT9V034_DS - Rev. A 10/08 EN
Pixel value = ADC value – dark column average + R0x71[9:0]
Row-wise noise correction is controlled by the following registers:
• R0x70 Row Noise Control
• R0x72 Row Noise Constant
Row-wise noise cancellation is performed by calculating a row average from a set of opti-
cally black pixels at the start of each row and then applying each average to all the active
pixels of the row. Read Dark Columns register bit and Row Noise Correction Enable
register bit must both be set to enable row-wise noise cancellation to be performed. The
behavior when Read Dark Columns register bit = 0 and Row Noise Correction Enable
register bit = 1 is undefined.
The algorithm works as follows:
Logical columns 755-790 in the pixel array provide 36 optically black pixel values. Of the
36 values, two smallest value and two largest values are discarded. The remaining 32
values are averaged by summing them and discarding the 5 LSB of the result. The 10-bit
result is subtracted from each pixel value on the row in turn. In addition, a positive
constant will be added (Reg0x71, bits 7:0). This constant should be set to the dark level
targeted by the black level algorithm plus the noise expected on the measurements of
the averaged values from dark columns; it is meant to prevent clipping from negative
noise fluctuations.
Note that this algorithm does not work in color sensor.
The integrated AEC/AGC unit is responsible for ensuring that optimal auto settings of
exposure and (analog) gain are computed and updated every frame.
AEC and AGC can be individually enabled or disabled by R0xAF. When AEC is disabled
(R0xAF[0] = 0), the sensor uses the manual exposure value in coarse and fine shutter
width registers. When AGC is disabled (R0xAF[1] = 0), the sensor uses the manual gain
value in R0x35 or R0x36. See “Pixel Integration Control” on page 52 for more informa-
tion.
Aptina Confidential and Proprietary
61
MT9V034: 1/3-Inch Wide-VGA Digital Image Sensor
Aptina Imaging reserves the right to change products or specifications without notice.
©2008 Aptina Imaging Corporation. All rights reserved.
Feature Description
(EQ 21)