Pixel
Smallest addressable element of a raster image.
A pixel (abbreviated px), pel, or picture element is the smallest addressable element of a raster image. In digital imaging, it is the fundamental unit used to represent and display visual information, forming the basis of modern computer graphics, photography, and video.
- field
- Digital imaging, computer graphics
- known_for
- Smallest addressable element of a raster image
Lore & Background
The concept of a picture element dates to the earliest days of electronic imaging. Billingsley of JPL, to describe the picture elements of scanned images from space probes to the Moon and Mars. Billingsley had learned the word from Keith E. McFarland, at the Link Division of General Precision in Palo Alto, who in turn said he did not know where it originated, stating it was 'in use at the time' (c. The word pixel is a combination of pix (from 'pictures', shortened to 'pics') and el (for 'element'); similar formations with 'el' include the words voxel 'volume pixel', and texel 'texture pixel'. In graphics and in image and video processing, pel is often used instead of pixel.
Reader's Guide
The pixel is a foundational concept in digital imaging, serving as the smallest controllable element in displays, printers, and raster images. Its significance extends from early consumer computer graphics, where large pixels were visible to the naked eye and gave rise to pixel art, to modern systems that render millions of pixels (megapixels). The term's meaning varies by context: it may refer to a numerical sample in an image file, a controllable picture element on a display, or a photosensitive element in a digital camera. Pixel counts are used as measurements, such as pixels per inch (ppi) for sampling density, distinct from dots per inch (dpi) for printer output. The arrangement of pixels in a regular two-dimensional grid enables uniform operations, though alternative patterns exist, such as staggered grids in LCDs or Bayer filters in digital cameras. The pixel scale in astronomy measures angular distance per pixel on detectors. Understanding pixels is essential for image resolution, display technology, and digital media.
Did You Know?
- Pixels are usually arranged in a regular two-dimensional grid, with each pixel storing one or more numerical values.
- The term 'pel' is often used instead of pixel in graphics and image processing, for example by IBM in their Technical Reference for the original PC.
Frequently Asked Questions
What is a pixel?
A pixel, short for 'picture element' (also abbreviated px or pel), is the smallest individually addressable unit within a raster image. It acts as the basic building block for all digital visual content, from still photographs to moving video.
What role does a pixel play in computer graphics?
Every raster-based image, video frame, or digital photograph is assembled from a grid of pixels, each storing its own color and intensity data. Without this fundamental unit, modern display technology and digital imaging would have no way to encode visual information.
Is 'pel' different from 'pixel'?
No—'pel' is simply an older abbreviation for 'picture element' that was common in early television and computing engineering. Both terms refer to the exact same smallest addressable element in a raster image.
Why is the pixel considered foundational to digital imaging?
Because every visual element in raster-based media is ultimately decomposed into individual pixels, making it the atomic unit of representation. All modern computer graphics, digital photography, and video pipelines depend on this concept as their starting point.
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