Bayer filter

The luminance perception of the human retina uses M and L cone cells combined, during daylight vision, which are most sensitive to green light.

The big advantage of the new CMY dyes is that they have an improved light absorption characteristic; that is, their quantum efficiency is higher.

To obtain a full-color image, various demosaicing algorithms can be used to interpolate a set of complete red, green, and blue values for each pixel.

Since the processing power of the camera processor is limited, many photographers prefer to do these operations manually on a personal computer.

Recording in Raw-format provides the ability to manually select demosaicing algorithm and control the transformation parameters, which is used not only in consumer photography but also in solving various technical and photometric problems.

There are other methods that make different assumptions about the image content and starting from this attempt to calculate the missing color values.

Images with small-scale detail close to the resolution limit of the digital sensor can be a problem to the demosaicing algorithm, producing a result which does not look like the model.

Smooth hue transition interpolation is used during the demosaicing to prevent false colors from manifesting themselves in the final image.

This effect occurs when the demosaicing algorithm averages pixel values over an edge, especially in the red and blue planes, resulting in its characteristic blur.

Another 2007 U.S. patent filing, by Edward T. Chang, claims a sensor where "the color filter has a pattern comprising 2×2 blocks of pixels composed of one red, one blue, one green and one transparent pixel," in a configuration intended to include infrared sensitivity for higher overall sensitivity.

The main reason for this type of array is to contribute to pixel "binning", where two adjacent photosites can be merged, making the sensor itself more "sensitive" to light.

Another reason is for the sensor to record two different exposures, which is then merged to produce an image with greater dynamic range.

This retained highlight information can then be blended in with the output from the other half of the sensor that is recording a 'full' exposure, again making use of the close spacing of similarly colored photosites.

Also, the new design is claimed to reduce the incidence of false colors, by having red, blue and green pixels in each line.

One of main drawbacks for custom patterns is that they may lack full support in third party raw processing software like Adobe Photoshop Lightroom[14] where adding improvements took multiple years.

[15] Sony introduced Quad Bayer color filter array, which first featured in the iPhone 6's front camera released in 2014.

Nonacell CFA is similar to Bayer filter, however adjacent 3x3 pixels are the same color, the 6x6 pattern features 9x blue, 9x red, and 18x green.