Technical Data
CoaXPress MC258x Camera Manual
8.3 Bayer pattern filter
The Eo
Sens
color cameras have a Bayer Pattern filter on their sensor glass lid. To get the col
or information the imaging software must decode the information for one pixel to RGB by using
the values of its neighbor pixels. There exists a lot of different Bayer Pattern algorithms, which
differ in speed and quality of the decoded image. You will find a lot of information and al
gorithms on the Internet which handle the Bayer Pattern thematic.
The Bayern Patter filter of the MC408x consists of a number small red, green and blue filter
elements, each covering exactly one pixel on the sensor. A matrix of 2 x 2 filter elements build
a filter element matrix. The order and the color of the filter elements building a 2 x 2 filter mat
rix are always the same. The image below shows the colors and the order of a filter matrix as
used by our cameras.
Red Green
Green
Blue
The sensor is completely covered by identically 2 x 2 filter matrix elements. So, the color pat
tern of the first line of the matrix is repeated each mod(2) pixel number on each even line num
ber. The color pattern of the second line is repeated on each (mod2) pixel on each odd line
number. That means, that always 2 consecutive lines shows exactly the same order of Bayer
Pattern elements.
Red
Green
Red
Green •••
Gree
n
Blue
Green
Blue
•••
Red
Green
Red
Green •••
Gree
n
Blue
Green
•••
•••
From the size and the order of a filter matrix element results...
•
Any (sub) region of a Bayer Pattern coded image must always start with the same color
on the top left (0/0) pixel position of the region.
•
A Bayer Pattern image must always have an even number of pixels and an even num
ber of lines.
•
Changing the image size can only be done by steps of 2 in the horizontal
and
in the
vertically direction.
48
