The pixels of the Bayer filter are arranged in a chequerboard pattern on the sensor. There are twice as many green as red and blue pixels in order to mimic the higher sensitivity of the human eye towards green light.
Due to the filter each pixel measures only one colour. The two remaining colours are estimated (interpolated) using the eight surrounding pixels. This technique is called Bayer demosaicing or Bayer to RGB Conversion.
The Bayer to RGB Conversion can be executed either in the camera itself, on the frame grabber, or on the host PC. For the camera, this conversion means a three times higher bandwidth for transfer and storage. For the host PC the conversion is usually very CPU intensive. A solution to such problems is the use of frame grabbers which perform the Bayer to RGB conversion in a FPGA (Field Programmable Gate Array).
An advantage of the Bayer filter method is the relatively low cost and the smaller size of the camera compared to three chip colour cameras, although the latter achieve greater colour fidelity and precision.
The filter inherited its name from its inventor Bryce E. Bayer who filed the patent for the method in the 1970s for the company Eastman Kodak.
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