mt9v032 aptina, mt9v032 Datasheet - Page 50

• Manufacturer Part Number: mt9v032
• Description: 1/3-inch Wide-vga Cmos Digital Image Sensor
• Manufacturer: aptina

Automatic Gain Control and Automatic Exposure Control
Figure 27:
Pixel Clock Speed
PDF: 6538045704/Source:2194051501
MT9V022_DS - Rev. C 9/10 EN
Controllable and Observable AEC/AGC Registers
The integrated AEC/AGC unit is responsible for ensuring that optimal auto settings of
exposure and (analog) gain are computed and updated every frame.
Automatic exposure control (AEC) and automatic gain control (AGC) can be individually
enabled or disabled by R0xAF. When AEC is disabled (R0xAF[0] = 0), the sensor uses the
manual exposure value in R0x0B. When AGC is disabled (R0xAF[1] = 0), the sensor uses
the manual gain value in R0x35. See Aptina Technical Note TN-09-81, “MT9V032 AEC
and AGC Functions,” for further
The exposure is measured in row-time by reading R0xBB. The exposure range is
1 to 2047. The gain is measured in gain-units by reading R0xBA. The gain range is
16 to 63 (unity gain = 16 gain-units; multiply by 1/16 to get the true gain).
When AEC is enabled (R0xAF[0] = 1), the maximum auto exposure value is limited by
R0xBD; minimum auto exposure is fixed at 1 row.
When AGC is enabled (R0xAF[1] = 1), the maximum auto gain value is limited by R0x36;
minimum auto gain is fixed to 16 gain-units.
The exposure control measures current scene luminosity and desired output luminosity
by accumulating a histogram of pixel values while reading out a frame. The desired
exposure and gain are then calculated from this for subsequent frame.
The pixel clock speed is same as the master clock (SYSCLK) at 26.66 MHz by default.
However, when column binning 2 or 4 (R0x0D, bit 2 or 3) is enabled, the pixel clock
speed is reduced by half and one-fourth of the master clock speed respectively. See
“Read Mode Options” on page 53 and “Column Binning” on page 55 for additional infor-
mation.
(desired luminance)
MAX. EXPOSURE
DESIRED BIN
MAX. GAIN
(R0xBD)
(R0x36)
(R0xA5)
16
1
MIN GAIN
MIN EXP.
GAIN LPF
(R0xAB)
EXP. LPF
(R0xA8)
51
details.
MT9V032: 1/3-Inch Wide-VGA Digital Image Sensor
GAIN SKIP
UNIT
UNIT
AEC
AGC
EXP. SKIP
(R0xA9)
(R0xA6)
HISTOGRAM
GENERATOR
UNIT
MANUAL GAIN
MANUAL EXP.
AGC OUTPUT
(R0x0B)
(R0x35)
OUTPUT
Aptina reserves the right to change products or specifications without notice.
AEC
AGC ENABLE
©2005 Aptina Imaging Corporation. All rights reserved.
(R0xAF[1])
AEC ENABLE
0
1
1
0
(R0xAF[0])
timing control
gain control
Feature Description
To exposure
To analog
R0xBA
R0xBB