Color filter array (CFA)
From The Glossary of Digital Photography
A device positioned over the top of an image sensor so that pixels, which only measure the amount of monochrome light, can be converted to colored light. Each pixel has a different color filter (red, green, or blue) than the array over it. The Bayer pattern is the most common color filter array. The ratio of the Bayer pattern is one red, two green, and one blue pixel. There are twice as many green pixels to more closely align the digital capture with human vision, corresponding to the sensitivity of the human eye to the color green. The color filter array is a mosaic pattern. To convert the resulting single red, green, and blue pixels into RGB pixels, software called demosaicing software is used to calculate the values of the missing colors for each pixel.
