Bayer sensor

Bayer sensor

The Bayer sensor is used in digital cameras and uses sensors that can detect only light levels — not colours. In order to create a full colour image the photosites on the sensor are covered with a three coloured Bayer filter usually in the pattern:

RGRGRG
GBGBGB
RGRGRG
GBGBGB

where R=red, G=green, B=blue.

There are 2 green sites for every red or blue as the cones in the human eye are more sensitive to green light.

Each photosite therefore records a red, green or blue level at a given pixel. To create a full colour image the colour components from these pixels need to be combined. There are several different algorithms to implement this which vary in image quality and processing time required. One of the effects of using a Bayer sensor is to lose the colour for small objects that only cover a few pixels. Aliasing artefacts are also common so most Bayer sensors employ an anti aliasing filter.