CV-M4+/M4+CL, CV-M7+/M7+CL
Color versions CV-M7+ and CV-M7+CL
These color cameras are identical to the monochrome cameras. Only the CCD sensor is changed to a RGB primary color type. Here the color mosaic lay out is shown in fig. 13. left. This lay out is known as a Bayer filter. Based on the knowledge to this mosaic, a full RGB signal can be constructed by some calculations in the host Pc as shown in the following example.
For the precise position of the R, G and B pixels in the mosaic, please refer to the table below. The output signal from the CCD sensor is not a complete RGB signal. Green values are missing where the blue and red pixels are placed. Blue values are missing where green and red pixels are placed. Red values are missing where the green and blue pixels are placed.
To have a complete RGB signal, values for the missing pixels can be constructed based on values of the adjacent pixels with the corresponding color.
From the color mosaic lay out it can be seen that signals from 3 adjacent lines are needed for the calculation of some of the missing pixel values. It is why binning can not be used for M7+.
The values for the missing blue (b) and red (r) pixels are calculated in 3 different ways. Some are based on adding the 4 diagonal placed pixels. The sum is then divided by 4. Other calculations are done by adding the 2 values. The upper and lower (or the left and the right) are added together, and the sum is divided by 2.
Missing green (g) pixels are all based on adding left + right + upper + lower and then divide the sum by 4. Shown in fig. 14. right.
G B G B G | Bul |
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R G R G R |
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G B G B G | Bll |
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| b=1/4(B | ur | +B +B +B ) | r=1/4(R | +R +R +R ) g=1/4(Gu+Gr+Gl+Gle) | |||||||
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| ur | ul | ll | lr |
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G | B | G | B | G | Bu |
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R | G | R | G | R | b | b=1/2(Bu+Bl) | r | r=1/2(Ru+Rl) |
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| Bl |
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| b=1/2(Br+Bl) |
| r=1/2(Rr+Rl) |
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Fig. 14. Color coding from a Primary RGB CCD (Bayer filter)
FVAL | LVAL |
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LVAL 7ck
G | R | G | R | G | R |
B | G | B | G | B | G |
G | R | G | R | G | R |
B | G | B | G | B | G |
Fig. 14 a. Bayer color sequence and position for CV-M7+ and CV-M7+CL
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