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Capturing Color

Camera hardware is colorblind, when capturing an image light hits a photosite and the intensity of the light is recorded as a voltage level. The camera than converts the analog voltage level to a digital representation. Filters are then applied inorder to achieve the color. There are three kids of filters, the Beam splitter, the Spinning disk filter, and the Color filter array.

Beam Splitter

The Beam Splitter has three separate filters for each color. Each sensor gets an identical look at the image, each sensor than takes care of one of the primary colors. An advantage of the Beam Splitter is the camera records all color information for each pixel. The disadvantage is it tends to make the camera bulky and expensive.

Spinning Disk Filter

The Spinning Disk Filter rotates a series of red, blue and green filters in front of a single sensor. It then records three separate images in rapid succession to achieve the full color image. The advantage of the Spinning Disk Filter is there is full color information in every pixel. The disadvantage is the camera and subject must be stationary.

Color Filter Array

The Color Filter Array is the more economical and practical way of recording color. It permanently places a filter over each individual photosite, breaking it up into RGB pixels. The representation it produces is not perfect but it gives enough information to “guess” the true color at a location. This is called interpolation.