LightnessLightness is a visual perception of the luminance(L){\displaystyle (L)} of an object. It is often judged relative to a similarly lit object. In colorimetry and color appearance models, lightness is a prediction of how an illuminated color will appear to a standard observer. While luminance is a linear measurement of light, lightness is a linear prediction of the human perception of that light.
Relative luminanceRelative luminance Y{\displaystyle Y} follows the photometric definition of luminance L{\displaystyle L} including spectral weighting for human vision, but while luminance L{\displaystyle L} is a measure of light in units such as cd/m2{\displaystyle cd/m^{2}}, relative luminance Y{\displaystyle Y} values are normalized as 0.0 to 1.0 (or 1 to 100), with 1.0 (or 100) being a theoretical perfect reflector of 100% reference white.
Gamma functionIn mathematics, the gamma function, denoted by Γ {\displaystyle \Gamma } (capital Greek letter gamma), is the most common extension of the factorial function to complex numbers. First studied by Daniel Bernoulli, the gamma function is defined for all complex numbers z {\displaystyle z} except non-positive integers, and satisfied Γ ( n ) = ( n − 1 ) ! {\displaystyle \Gamma (n)=(n-1)!} for every positive integer n {\displaystyle n} .
JPEGLossy compression method for reducing the size of digital imagesContinuously varied JPEG compression (between Q=100 and Q=1) for an abdominalCT scanJPEG ( , short for Joint Photographic Experts Group and sometimes retroactively referred to as JPEG 1) is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography.
VideoVideo is an electronic medium used for the recording, copying, playback, transmission, and display of moving visual images and pictures, with or without accompanying audio. Video technology was initially developed for live transmission and later expanded to include recording and storage through analog formats such as magnetic tape.
ImageAn image or picture is a visual representation. An image can be two-dimensional, such as a drawing, painting, or photograph, or three-dimensional, such as a carving or sculpture. Images may be displayed through other media, including a projection on a surface, activation of electronic signals, or digital displays; they can also be reproduced through mechanical means, such as photography, printmaking, or photocopying.
RGB color modelThe RGB color model is an additive color model in which the red, green, and blue primary colors of light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three additive primary colors— red, green, and blue.Power lawIn mathematics and science, a power law is a functional relationship between two quantities, where a relative change in one quantity results in a relative change in the other quantity proportional to the change raised to a constant exponent: one quantity varies as a power of another. The change is independent of the initial size of those quantities.
RGB color spacesRGB color spaces are a category of additive colorimetric color spaces specifying part of its absolute color space definition using the RGB color model. RGB color spaces are commonly found describing the mapping of the RGB color model to human perceivable color, but some RGB color spaces use imaginary (non-real-world) primaries and thus can not be displayed directly.
Stevens's power lawStevens' power law is an empirical relationship in psychophysics between an increased intensity or strength in a physical stimulus and the perceived magnitude increase in the sensation created by the stimulus. It is often considered to supersede the Weber–Fechner law, which is based on a logarithmic relationship between stimulus and sensation, because the power law describes a wider range of sensory comparisons, down to zero intensity.
Cathode ray tubeVacuum tube used to display imagesCathode ray tube cross section diagram (not to scale) with its focused and deflected electron beam (in green)Oscilloscope cathode ray tubeCutaway rendering of a color CRT:Electron guns (cathodes) for red, green, and blueElectron beamsFocusing coilsDeflection coilsAnode connectionShadow mask for separating beams for red, green, and blue parts of the displayed imagePhosphor layerClose-up of the phosphor layer showing red, green, and blue zonesCutaway rendering of a monochrome CRT:Deflection coilsElectron beamFocusing coilPhosphor layerFilament for heating the cathodeGraphite layer on the inner side of the tubeAnode connectionElectron gun (cathode)Air-tight glass body of the tubeScreenDeflection yokeControl electrode modulating the intensity of the electron beamContact pins for cathode, filament and control electrodeWire for anode high voltageThe only visible differences are the single electron gun, the uniform white phosphor coating, and the lack of a shadow mask.A Macintosh computer from the 1990s with integrated CRT displayA cathode ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams, which are directed and controlled to display images on a phosphorescent screen.
Nonlinear systemIn mathematics and science, a nonlinear system (or a non-linear system) is a system in which the change of the output is not proportional to the change of the input. Nonlinear problems are of interest to engineers, biologists, physicists, mathematicians, and many other scientists since most systems are inherently nonlinear in nature.
Floating-point arithmeticComputer approximation for real numbersAn early electromechanical programmable computer, the Z3, included floating-point arithmetic (replica on display at Deutsches Museum in Munich).In computing, floating-point arithmetic (FP) is arithmetic on subsets of real numbers formed by a significand (a signed sequence of a fixed number of digits in some base) multiplied by an integer power of that base. Numbers of this form are called floating-point numbers.*As an Amazon Associate I earn from qualifying purchases.