User`s manual

Operation and Features

3-18 BASLER A302f

DRAFT

3.10 Color Creation in the A302fc

The CCD sensor used in the A302fc is equipped with an additive color separation filter known as

a Bayer filter. With the Bayer filter, each individual pixel is covered by a micro-lens which allows

light of only one color to strike the pixel. The pattern of the Bayer filter used in the A302

fc is shown

in Figure 3-14. As the figure illustrates, within each block of four pixels, one pixel sees only red

light, one sees only blue light, and two pixels see only green light. (This combination mimics the

human eye’s sensitivity to color.)

Figure 3-14: Bayer Filter Pattern on the A302

When an A302fc is operating in a color output mode, each pixel goes through a two step

conversion process as it exits the sensor and passes through the camera’s electronics.

In the first step of the process an interpolation algorithm is performed to get full RGB data for the

pixel. (Because each individual pixel gathers information for only one color, an interpolation must

be made from the surrounding pixels to get full RGB data for an individual pixel.)

Since the 1394 Digital Camera Specification requires that color information be transmitted as

YUV, the second step of the process is to convert the RGB information to YUV. The conversion

algorithm uses the following formulas:

Y = 0.3 R + 0.59 G + 0.11 B

U = -0.168 R - 0.33 G + 0.498 B

V = 0.499 R - 0.421 G - 0.078 B

Horizontal Shift

GRGR

GBGB

GRGR

GBGB

GRGR

GBGB

GRGR

GBGB