Pixel - In digital imaging, a pixel, pel,[1] or picture element[2] is a physical point in a raster image, or the smallest addressable element in an all points addressable display device; so it is the smallest controllable element of a picture represented on the screen. 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 color image systems, a color 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 a photosite in the camera sensor context, although the neologism sensel is sometimes used to describe the elements of a digital camera's sensor),[3]
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.
