Color Creation and Enhancement AW00123402000
158 Basler ace USB 3.0
YUV Formats
Most color cameras with a Bayer filter can output color images based on pixel data in YCbCr422_8
format.
When a color camera is set for this format, each pixel value in the captured image goes through a
two step conversion process as it exits the sensor and passes through the camera’s electronics.
This process yields Y, Cb, and Cr color information for each pixel.
In the first step of the process, a demosaicing algorithm is performed to get RGB data for each pixel.
This is required because color cameras with a Bayer filter on the sensor gather only one color of
light for each individual pixel.
The second step of the process is to convert the RGB information to the YCbCr color model. The
conversion algorithm uses the following formulas:
Y = 0.299 R + 0.587 G + 0.114 B
Cb = - 0.16874 R - 0.33126 G + 0.5000 B + 128
Cr = 0.5000 R - 0.41869 G - 0.08131 B + 128
After conversion to the YCbCr color model is complete, the pixel data is transmitted to the host PC.
Mono Format
Most cameras equipped with a Bayer pattern color filter can output monochrome images based on
pixel data in the Mono 8 format.
When a color camera is set for Mono 8, the pixel values in each captured image are first
demosaiced and converted to the YCbCr color model as described above. The camera then
transmits the 8 bit Y value for each pixel to the host PC. In the YCbCr color model, the Y component
for each pixel represents a brightness value. This brightness value can be considered as equivalent
to the value that would be sent from a pixel in a monochrome camera. So in essence, when a color
camera is set for Mono 8, it outputs an 8 bit monochrome image. (This type of output is sometimes
referred to as "Y Mono 8".)
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