concept

pixel

The smallest unit of a digital image, representing a single point of data.
10 related articles

Description

A pixel is the smallest addressable element in a digital image, a single point of data that, when combined with millions of others, forms a complete picture. Each pixel carries numerical information about color and brightness, typically represented as a combination of red, green, and blue intensities. The resolution of an image — its sharpness and detail — is determined by the number of pixels it contains, with more pixels allowing finer gradations of visual information.

History

The term 'pixel' was coined in 1965 by Fred C. Billingsley, an engineer at NASA's Jet Propulsion Laboratory, to describe the picture elements in television and digital images.

How it works

In a digital camera, light strikes a sensor made of millions of photodiodes, each converting photons into an electrical charge proportional to the light's intensity. This charge is then quantized into a digital value, often 8 or 12 bits per color channel. The resulting grid of numbers is what a computer stores and displays, with each pixel's color reproduced by tiny light emitters on a screen.

In practice

Pixels are fundamental to all digital imaging — from smartphone cameras and medical X-rays to satellite imagery and computer graphics, where every visual output is ultimately a grid of pixels.

Fun fact

A single 4K television screen contains over 8 million pixels, yet each one is so small that individual pixels are invisible to the naked eye at normal viewing distances.

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Related articles · 10

A Million Frames per Second: How a Camera Sees Only What Matters
You're looking for fireflies in a dark forest. Instead of photographing the whole forest every second and then poring over the images, you carry a small device that spots the flashes on its own and cuts out only a circle around each one. The rest, the blackness, isn't saved. That's exactly how the new sensor for scientific cameras works.
Optics2026-08-132 minarXiv:2608.13019express
A Color Router That Sees Like a Camera
A smartphone camera captures light with tiny sensors, but by themselves, they can't distinguish colors. So color filters are placed in front of them: red, green, blue, like stained glass in a window. Each sensor sees only its own color, and then software assembles the full picture from these pieces.
Biological Physics2026-08-092 minarXiv:2608.08816express
The Boundary Sees All Better
If a smell seeps into a room through a slightly open door, you could stand in the middle and sniff. But the most accurate way to catch the moment the smell arrives is to stand right at the threshold. A cell behaves much the same way when it needs to measure the concentration of a substance around it.
Shadow Symphony: How Data Became a Portrait of a Black Hole
In 2019, the world saw the first image of a black hole's shadow — an orange doughnut on a black background, becoming a symbol of scientific progress. But this image wasn't captured by a camera: it was born from mathematical alchemy, where data from eight radio telescopes, which gathered only crumbs of signal, merged into a single picture.
How pixel timing reveals a particle's angle of incidence
A charged particle streaks through a silicon sensor, leaving behind a trail of free electrons. The time it takes for this charge to be collected at the electrode depends on how deep in the crystal it was born. A particle entering head-on carves identical paths through neighboring pixels: their signals arrive almost simultaneously.
Quantum Physics2026-04-302 minarXiv:2604.27761express
Counting Light, Drop by Drop
An ordinary rain gauge collects water in a bucket and shows the total volume of precipitation. But the new device is like a sensitive palm that feels every falling drop and keeps count, even when the drops number in the thousands. That's exactly what physicists have built.
Optics2026-02-201 minarXiv:2602.18343express
X-ray microscope sees twice as clearly
An X-ray image of a battery looks like a photo taken through frosted glass: fine details blur into a gray smudge. The culprit is the detector itself, which cannot distinguish features smaller than its pixel size. Engineers proposed getting around this barrier by illuminating the sample not with a uniform beam but with a striped pattern.
Optics2026-01-171 minarXiv:2601.12162express
A Camera That Sees the Unseen
Light is like a many-voiced choir: color, direction of oscillation, and instantaneous changes all intertwine. An ordinary camera hears only one voice, while the rest are lost. Scientists have built a camera that listens to the entire choir at once, and from a single image understands what is happening.
How to Make Images Taken in Different Languages Get Along
Two images of the same place: one taken in the morning from a drone, the other in the evening from a satellite. The first shows shadows from trees, the second shows glints on the water. It's like two accounts of the same event in different dialects: the words are similar, but the grammar is different.
Depth as a Measure of Natural Complexity
A team assembling a jigsaw puzzle from random pieces: how many simultaneous moves does it take to complete the picture? If the pieces are independent, they all go down at once. If each piece depends on the previous one, you have to work one at a time. So it is with systems: some states assemble instantly, others require a long sequential effort.