ICM202B IC Media, ICM202B Datasheet - Page 6

• Manufacturer Part Number: ICM202B
• Description: CIF/QCIF CMOS image sensor
• Manufacturer: IC Media

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Auto Exposure
The Auto Exposure circuit control the Exposure Time, Digital Gain, and Anti-flickering function
automatically. The following features are provided:
The following registers are use to control these features:
0x3A (AD_AE_CTRL, Default = 7)
0x3B (AD_AE_HIGH,AE Target value High Limit, Default = 0x65)
0x3C (AD_AE_LOW,AE Target value Low Limit, Default = 0x55)
0x3F,0x40 (AD_MAXFH, Maximum Frame Height, Default = 0xfff)
0x41,0x42 (AD_MINFH, Minimum Frame Height, Default = 0x190)
0x44 (AD_AFSTEP, Anti-flickering Exposure Time Step, Default = 0x64)
1.4 Color Interpolation
Since the raw data coming out the sensor array has only one of the R, G, or B value for each pixel, we need
to perform interpolation to obtain a set of correlated RGB value for each pixel. The method used is based
on a 3x3 interpolation window. The result of this operation is a data stream consisting of 24-bit RGB per
pixel. After this step, the whole frame can be viewed as a color picture. However, since the RGB filters
and the photodiode are not perfect, the RGB values may have different strength. In addition, there are
some cross-talk among the RGB channels. That’s why we need the color correction (or white balancing)
step.
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. Disable/Enable AE
. Disable/Enable Anti-flickering
. Disable/Enable Digital Gain
. Disable/Enable Fix Frame Rate
. Adjustable Maximum/Minimum Frame Rate
. Adjustable AE Target brightness value
bit 0 : Disable/Enable AE
bit 1 : Disable/Enable Digital Gain
bit 2 : Disable/Enable Anti-flickering
bit 3 : Disable/Enable Fix Frame Rate
The default value enable AE, Anti-flickering, and Digital Gain.
Use AD_AEHIGH and AD_AELOW to set the target brightness of AE function.
AD_MAXFH set the minimum frame rate of AE .
AD_MINFH set the maximum frame rate of AE .
Use AD_AFSTEP to setup 50 /60HZ Anti-flickering step.
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ICM202B CIF/QCIF CMOS sensor with digital YUV output
page 6
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Data Sheet V2.0, February 2003
Confidential
2/5/2003