MT9D115 Datasheet, PDF (30/66 Pages) ON Semiconductor – CMOS Digital Image Sensor

Figure 23: Gamma Correction Curve
MT9D115: 1/5-Inch SOC Digital Image Sensor
Architecture
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Gamma Correction
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Input RGB, 12-bit
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Color Kill
A color kill circuit is included to remove high or low light color artifacts. It affects only
pixels whose luminance exceeds a certain preprogrammed threshold. The U and V
values of those pixels are attenuated proportionally to the difference between their lumi-
nance and the threshold.
Digital Scaling/Output Format
Special Effects
Special effects like negative image, sepia, or black and white can be applied to the data
stream at this point. These effects can be enabled and selected by registers.
RGB to YUV Conversion
For further processing, the data is converted from RGB color space to YUV color space.
YUV Color Filter
As an optional processing step, noise suppression by one-dimensional low-pass filtering
of Y and/or UV signals is possible. A 3- or 5-tap filter can be selected for each signal.
Image Scaling
The IFP includes a scaler module to ensure that the size of images output by the
MT9D115 can be tailored to the needs of all users. When enabled, this module performs
rescaling of incoming images—shrinks them to arbitrarily selected width and height
without reducing the field of view and without discarding any pixel values.
The scaler performs pixel binning—divides each input image into rectangular bins
corresponding to individual pixels of the desired output image, averages pixel values in
these bins, and assembles the output image from the bin averages. Pixels lying on bin
boundaries contribute to more than one bin average; their values are added to bin-wide
sums of pixel values with fractional weights. The entire procedure preserves all image
information that can be included in the downsized output image and filters out high
frequency features that could cause aliasing.
Use the image cropping and scaler module together to implement a digital zoom and
pan. If the scaler is programmed to output images smaller than images coming from the
sensor core, zoom effect can be produced by cropping the latter from their maximum
MT9D115 DS Rev. E Pub. 4/15 EN
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