Picture Resolutions and Pixels

What's a Pixel

In digital imaging, a pixel, or pel, (picture element) is a physical point in a raster image, or the smallest addressable element in a display device; so it is the smallest controllable element of a picture represented on the screen. The address of a pixel corresponds to its physical coordinates. LCD pixels are manufactured in a two-dimensional grid, and are often represented using dots or squares, but CRT pixels correspond to their timing mechanisms and sweep rates.

Each pixel is a sample of an original image; more samples typically provide more accurate representations of the original. The intensity of each pixel is variable. In colour image systems, a colour is typically represented by three or four component intensities such as red, green and blue or cyan, magenta, yellow and black

In some contexts (such as descriptions of camera sensors), the term pixel is used to refer to a single scalar element of a multi-component representation (more precisely called aphotosite in the camera sensor context, although the neologism sensel is sometimes used to describe the elements of a digital camera's sensor), while in others the term may refer to the entire set of such component intensities for a spatial position. In color systems that use chroma subsampling, the multi-component concept of a pixel can become difficult to apply, since the intensity measures for the different color components correspond to different spatial areas in such a representation.

The word pixel is based on a contraction of pix ("pictures") and el (for "element"); similar formations with el for "element" include the words voxel and texel.

What's Resolution?