In digital imaging, a pixel (picture element) is the smallest piece of information in an image. Pixels are normally arranged in a regular 2-dimensional grid, and are often represented using dots, squares, or rectangles. Each pixel is a sample of an original image, where more samples typically provide a more accurate representation of the original. The intensity of each pixel is variable; in color systems, each pixel has typically three or four components such as red, green, and blue, or cyan, magenta, yellow, and black.

The word pixel is based on a contraction of pix (for "pictures") and el (for "element"); similar formations with el for "element" include voxel, luxel,Fact: date=June 2008 and texel.

Etymology

The word pixel was first published in 1965 by Frederic C. Billingsley of JPL, to describe the picture elements of video images from space probes to the moon and Mars; but he did not coin the term himself, and the person he got it from (Keith E. McFarland at the Link Division of General Precision in Palo Alto) does not know where he got it, but says it was "in use at the time" (circa 1963).

The word is a combination of picture and element, via pix. Pix was first coined in 1932 in a Variety magazine headline, as an abbreviation for the word pictures, in reference to movies; by 1938 pix was being used in reference to still pictures by photojournalists.

The concept of a picture element dates to the earliest days of television, for example as Bildpunkt (the German word for pixel, literally picture point) in the 1888 German patent of Paul Nipkow. According to various etymologies, the earliest publication of the term picture element itself was in Wireless World magazine in 1927,though it had been used earlier in various U.S. patents filed as early as 1911.1

Some authors explain pixel as picture cell, as early as 1972.

A detailed history of pixel and picture element, with references, is linked below.

In video processing, Pel is often used instead of pixel. For example, IBM used it in their Technical Reference for the original PC.

Words with similar etymologies

Texel (texture element) and Luxel (Lux Element) are words used to describe a pixel when it is used in specific context (texturing and light mapping respectively)