A pixel is one picture element at an indexed position in a raster image. It can contain a single grayscale value or several colour components. The word can also refer to a physical display element; the indexed element of the stored image is the meaning used here. One stored pixel need not occupy exactly one physical display element when the image is resized. Microsoft's bitmap documentation likewise distinguishes an image's grid and its numerical colour representation.[ref]
Separate position from value: raster sampling and reconstruction concerns the spatial grid, while sample depth concerns how many bits encode each component. Four times as many pixels can describe a finer grid without improving the quantization of any value. Conversely, more bits per sample can distinguish more shades without locating an edge more precisely.
In the binary example under run-length encoding, one bit per pixel selects black or white. In the grayscale example under lossy block averaging, eight bits per pixel select one of 256 codes. Calling them codes keeps their numerical values distinct from the physical light that a display emits.

Articles by others on the same topic (NaN)

The term "Pixel" can refer to different things depending on the context. Here are some common meanings: 1. **In Digital Imaging**: A pixel (short for "picture element") is the smallest unit of a digital image that can be displayed or processed on a digital display system. Pixels combine to form images, and their resolution is often described in terms of width x height (e.g., 1920 x 1080 pixels).