RM/TM-1405GE Series
16
Operation
3
Operation
3.1
Progressive Scanning
The TM-1405GE uses a state-of-the-art progressive scanning interline transfer CCD which scans all
lines sequentially from top to bottom at one frame rate. Like a non-interlace computer screen, it
generates a stable, crisp image without alternating lines and provides full vertical TV resolution of
1040 lines.
The interline transfer architecture is also important to generate simultaneous shuttering. This is
different from full frame transfer architecture, which requires a mechanical shutter or strobe light in
order to freeze the object motion.
The TM-1405GE outputs the progressive scanned image with an electronic shutter in two different
formats.
•
Progressive scanning digital - The CCD signal goes through A/D converters 10-bit in, 10-bit/8-bit
out. The digital output is available using the Gigabit Ethernet connector.
•
Analog output - The analog output is the same as 75 ohms, 714mV format available from BNC
and 12-pin connector. Analog video does not conform to the RS-170 standard and is not RS-170
compatible.
3.2
Bayer Color Filter (Color Versions)
JAI 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 1/21,000 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.
3.2.1
Color Filter Array
JAI 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.
3.2.2
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.
