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Pixel

technology Maturity 9-11 Next article →

A pixel, often abbreviated as px, is the smallest addressable physical element of a raster image. It is also the smallest controllable element found in a display device or a dot matrix printer. You can think of pixels as the fundamental building blocks of digital imagery. These tiny elements are arranged in a regular, two-dimensional grid. Each pixel acts as a single sample of an original image. When a system uses a higher number of these samples, it provides a more accurate representation of the subject.

Pixel-example
Pixel-example

The way a pixel creates color is a fascinating process of mixing intensities. In most color imaging systems, a pixel is composed of three or four component intensities. For example, many digital displays use the RGB model, which stands for red, green, and blue. Other systems, such as those used in printing, use the CMYK model, which includes cyan, magenta, yellow, and black. The intensity of each component is variable. By combining these different intensities, the system can produce a wide spectrum of colors.

Pixel geometry 01 Pengo
Pixel geometry 01 Pengo

Inside a single pixel, there are even smaller components known as subpixels. On many liquid-crystal displays (LCDs), these subpixels are arranged in a staggered grid. This means the red, green, and blue components are sampled at slightly different locations. Technology like ClearType uses this subpixel arrangement to improve how text is rendered on a screen. This makes the edges of letters look much smoother to the human eye.

Wikipedia ClearType
Wikipedia ClearType

While pixels are usually square, some systems use rectangular pixels that are oblong in shape.

Closeup of pixels
Closeup of pixels

The history of the picture element stretches back much further than the modern computer. The concept appeared in an 1888 German patent by Paul Nipkow, where it was called "Bildpunkt," meaning "picture point." The term "pixel" itself is a combination of "pix," a shortening of "pictures," and "el," for "element." The word "pix" appeared in magazine headlines as early as 1932. However, the specific term "pixel" was first published in 1965 by Frederic C. Billingsley. He used it to describe the picture elements of images scanned from space probes sent to the Moon and Mars.

ReconstructionsFromPixels
ReconstructionsFromPixels

We can measure the detail of an image by looking at its resolution. This is often expressed in terms of how many pixels are used. For instance, a "three-megapixel" camera contains approximately three million pixels. Pixel counts can also be given as a pair of numbers, such as a 640 by 480 display. This specific VGA display contains a total of 307,200 pixels. Modern displays can render orders of magnitude more pixels than early computers could.

Sensorauflösungen
Sensorauflösungen

Because early computers had such low resolution, their large pixels were visible to the naked eye. This specific aesthetic is known as pixel art, which is common in older video games.

The number of colors a pixel can show depends on its bit depth, or bits per pixel (bpp). Each additional bit doubles the number of available colors. A 1 bpp image is monochrome, meaning it only has two colors: on or off. An 8 bpp image can show 256 colors, while a 24 bpp image can represent 16,777,216 colors, a standard known as "Truecolor." Some advanced systems use 32-bit depth, which adds an extra 8 bits to describe the opacity, or how see-through an image is. This allows different images to be combined effectively.

Pixels are used in many different scientific fields beyond just computer screens. In digital cameras, the term may refer to a single photosite on a sensor. In astronomy, the pixel scale is measured as the angular distance between two objects in the sky. This is calculated using the ratio of pixel spacing to the focal length of the telescope's optics. Whether they are used in a smartphone, a printer, or a massive telescope, pixels allow us to translate the physical world into digital data.

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🖼️ Images & Media (9)
File:Pixel-example.png
Pixel-example.png
File:Closeup of pixels.JPG
Closeup of pixels.JPG
File:ReconstructionsFromPixels.png
ReconstructionsFromPixels.png
File:FILE Hipersônica Rio 09 - 8 BIT Game People, Festival Internacional de Linguagem Eletrônica.jpg
FILE Hipersônica Rio 09 - 8 BIT Game...
File:Wikipedia ClearType.png
Wikipedia ClearType.png
File:Pixel geometry 01 Pengo.jpg
Pixel geometry 01 Pengo.jpg
File:Samsung TV subpixels..jpg
Samsung TV subpixels..jpg
File:Sensorauflösungen.svg
Sensorauflösungen.svg
File:Megapixel_comparison.jpg
Megapixel_comparison.jpg
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