Sunday, March 20, 2011

Color camera technology

CCD and CMOS sensors put out electrons in response to photons that land on their silicon surface. They have no knowledge of the wavelength of the light that fell on them. So how, you might be wondering, does the camera know when to put out red, green or blue?

Well most color cameras use a Bayer filter over the CCD sensor. This red, green and blue mosaic filters photons by color so that some pixels only receive red, some blue and the rest green. In fact I thought that was the way all color cameras did things, but thanks to an article on the Basler web site, I now know better.

Color Creation with Interlaced Sensors – How Does That Work?” describes how the Sony ICX409 sensor creates color images. What’s interesting is that it uses a four color filter – green, magenta (pink), cyan (blue) and yellow – and a complex binning process to produce color images. There’s some good detail in the article, so if this is something that interests you, take a look.

1 comment:

Anonymous said...

Nice to have "special case" to explain Bayer conversion (the sensor seems to be made for interlaced PAL image).

I imagine that basic red, green, blue -filter is much common in digital image sensors.