JAI Progressive Scan Shutter Cameras, TM-6760 operation manual Bayer Color Filter Array CFA

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TM-6760 Series Progressive Scan Shutter Cameras

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.

3.11.1 Color Filter Array

JAI, Inc. 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, either Camera Link or RS-644, allows the camera to output accurate pixel data, including the color information. When the data is stored in the frame buffer of a framegrabber 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.

3.11.2 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 framegrabber and color interpolation to know where the individual color pixels exist relative to sync (LDV and FDV) timing.

FIGURE 9. Bayer Color Filter Array

Quantum Efficiency (%)

25%

G

20%

R

B

15%

10%

5%

0%

400 450 500 550 600 650 700 750 800 850 900 950 1000

Wavelength (nm)

Operation