Instruction manual

Page 38
Operation
TM-1405GE Hardware
8.2 Bayer Color Filter (Color Versions)
JAI PULNiX AccuPiXEL series color cameras are high-resolution, high-speed progressive scan CCD
cameras. The interline transfer, progressive scan CCD permits full vertical and horizontal resolution of
images acquired at very high shutter speeds. The electronic shutter, which has speeds to 1/16,000 sec.,
can be reset asynchronously by external pulse control. Uniform square pixels provide superior image
definition in any orientation. On-chip micro lenses mean increased sensitivity.
8.2.1 Color Filter Array
JAI PULNiX AccuPiXEL cameras use Bayer CFA (color filter array) as their standard primary color
filter. This filter provides the most popular color interpolation supported by numerous software
suppliers.
The digital format allows the camera to output accurate pixel data, including the color information.
When the data is stored in the frame buffer of a frame grabber or computer, the color information is
easily manipulated to restore the original color images. Because the color filter array contains only a
single R, G or B color in each pixel, the restored image has to fill in colors in the missing pixel
locations. The software uses neighboring pixel information to “guess” the missing colors to make
smooth, clear images. This is called “color interpolation.” Today’s high-speed computers allow such
color interpolation to be done almost in real time. Because these cameras do not contain internal color-
processing circuitry, they are smaller and less expensive than full-function color cameras.
8.2.2 Bayer Color Filter Array (CFA)
The Bayer CFA is an R, G, B primary color filter array. This is the most widely accepted CFA for the
single-chip CCD progressive scan format. This type of array layout has a specific order for each color’s
pixels. Since the human eye’s resolution and color recognition are highest at green, the CFA contains
two greens per each red and blue.
It is critical for the frame grabber and color interpolation to know where the individual color pixels exist
relative to sync (LDV and FDV) timing.
This requirement makes digital output the preferred choice, because the timing relationships are very
accurate