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A color filter array, or CFA, also known as a color filter mosaic or color subsampling array, is a microscopic grid of tiny color filters placed over the pixels of an image sensor, such as a CCD or CMOS sensor. This array allows a single sensor to capture color information, which is a fundamental process in digital photography and imaging. Without a color filter array, a digital camera sensor would only be able to capture the intensity of light, resulting in a monochrome image.

The most common type of CFA is the Bayer filter array, which arranges red, green, and blue filters in a repeating pattern. Typically, this pattern consists of alternating rows of red and green filters, and alternating rows of green and blue filters, with twice as many green filters as red or blue. This is because the human eye is most sensitive to green light. Other CFA patterns exist, such as RGBE (red, green, blue, emerald) or RGGB (red, green, green, blue), each with slight variations in color capture and processing.

When light strikes the image sensor, each pixel beneath a filter only records the intensity of the light passing through that specific color filter. For example, a pixel under a red filter will only register the red component of the light. To reconstruct a full-color image, a process called demosaicing or debayering is then applied. This algorithm interpolates the missing color information for each pixel based on the values of its neighboring pixels, creating a complete color image from the initial mosaic of color-filtered data. The design and effectiveness of the CFA significantly influence the final color fidelity and resolution of the captured image.