VS6724 Datasheet, PDF (17/118 Pages) STMicroelectronics – 2 Megapixel single-chip camera module

VS6724
Functional description
2.5.2
2.5.3
2.5.4
2.5.5
2.5.6
Aperture correction
The aperture correction module is used to add a certain amount of sharpening to the scaled
RGB, it can be programmed to reduce as the light level drops. The aperture correction
module also includes a function known as coring which allows control of the minimum
magnitude which any edge on the image must exceed before sharpening is applied. This
ensures that small edges such as noise are not amplified by the sharpening. The coring can
be programmed to increase as the light level drops.
Special effects
The special effects module is used to apply simple transforms onto the input data. The
supported effects are: Black and White, Hue, Sepia, Negative, Antique, sketch, caricature
and Emboss. There are also a number of color effects which can only be applied to YCbCr
data.
Gamma correction
The gamma module is a gain curve applied to each of the three image components from the
sharpening module. The shape of the gain curve is fully programmable.
YCbCr conversion
This module performs color space conversion from RGB to YCbCr. It is used to control the
contrast and color saturation of the output image as well as the fade to black feature.
Dither
The dither block is used in RGB modes to reduce contouring in the image when the data is
truncated to lower ranges. This is achieved by determining the error introduced by truncation
and adding/subtracting this residual energy to/from the subsequent pixel.
2.6
2.6.1
Video compression module
The JPEG encoder receives YCbCr data from the image reconstruction engine and
encodes it using baseline sequential JPEG technique. It outputs a standard JPEG data
stream with all the required markers and segments required by decoders.
Features
● Supports YCbCr 422 as input data format.
● Converts YCbCr 422 to 420 format internally, format selectable.
● Baseline ISO/ IEC 10918-1 JPEG compliance.
● Programmable quantization tables.
● Capable of streaming the UXGA image at a rate of 30 frames per second.
● Manual / automatic compression control via scaled quantization tables.
● Automatic compression control targeted at file size and/or peak bit-rate.
● Progressive high-frequency roll-off option for increased compression.
● Intraframe rate-control via zig-zag sequence truncation.
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