Sample (graphics)

Last updated

In computer graphics, a sample is an intersection of a channel and a pixel. [1]

The diagram below depicts a 24-bit pixel, consisting of 3 samples for Red, Green, and Blue.

Different samples within a pixel PixelSamples.png
Different samples within a pixel

In this particular diagram, the Red sample occupies 9 bits, the Green sample occupies 7 bits and the Blue sample occupies 8 bits, totaling 24 bits per pixel. Note that the samples do not have to be equal size and not all samples are mandatory in a pixel.

Also, a pixel can consist of more than 3 samples (e.g. 4 samples of the RGBA color space).

A sample is related to a subpixel on a physical display.

Related Research Articles

<span class="mw-page-title-main">Pixel</span> Physical point in a raster image

In digital imaging, a pixel, pel, or picture element is the smallest addressable element in a raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, pixels are the smallest element that can be manipulated through software.

<span class="mw-page-title-main">PNG</span> Family of lossless compression file formats for image files

Portable Network Graphics is a raster-graphics file format that supports lossless data compression. PNG was developed as an improved, non-patented replacement for Graphics Interchange Format (GIF)—unofficially, the initials PNG stood for the recursive acronym "PNG's not GIF".

<span class="mw-page-title-main">RGB color model</span> Color model based on red, green, and blue

The 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.

<span class="mw-page-title-main">Chroma subsampling</span> Practice of encoding images

Chroma subsampling is the practice of encoding images by implementing less resolution for chroma information than for luma information, taking advantage of the human visual system's lower acuity for color differences than for luminance.

The BMP file format or bitmap, is a raster graphics image file format used to store bitmap digital images, independently of the display device, especially on Microsoft Windows and OS/2 operating systems.

<span class="mw-page-title-main">RGBA color model</span> RGB color model with an opacity channel

RGBA stands for red green blue alpha. While it is sometimes described as a color space, it is actually a three-channel RGB color model supplemented with a fourth alpha channel. Alpha indicates how opaque each pixel is and allows an image to be combined over others using alpha compositing, with transparent areas and anti-aliasing of the edges of opaque regions.

In computing, on the X Window System, X11 color names are represented in a simple text file, which maps certain strings to RGB color values. It was traditionally shipped with every X11 installation, hence the name, and is usually located in <X11root>/lib/X11/rgb.txt. The web colors list is descended from it but differs for certain color names.

Web colors are colors used in displaying web pages on the World Wide Web; they can be described by way of three methods: a color may be specified as an RGB triplet, in hexadecimal format or according to its common English name in some cases. A color tool or other graphics software is often used to generate color values. In some uses, hexadecimal color codes are specified with notation using a leading number sign (#). A color is specified according to the intensity of its red, green and blue components, each represented by eight bits. Thus, there are 24 bits used to specify a web color within the sRGB gamut, and 16,777,216 colors that may be so specified.

<span class="mw-page-title-main">D-1 (Sony)</span> Magnetic tape-based videocassette format

D-1 or 4:2:2 Component Digital is an SMPTE digital recording video standard, introduced in 1986 through efforts by SMPTE engineering committees. It started as a Sony and Bosch – BTS product and was the first major professional digital video format. SMPTE standardized the format within ITU-R 601, also known as Rec. 601, which was derived from SMPTE 125M and EBU 3246-E standards.

Color depth or colour depth, also known as bit depth, is either the number of bits used to indicate the color of a single pixel, or the number of bits used for each color component of a single pixel. When referring to a pixel, the concept can be defined as bits per pixel (bpp). When referring to a color component, the concept can be defined as bits per component, bits per channel, bits per color, and also bits per pixel component, bits per color channel or bits per sample (bps). Modern standards tend to use bits per component, but historical lower-depth systems used bits per pixel more often.

The RGB chromaticity space, two dimensions of the normalized RGB space, is a chromaticity space, a two-dimensional color space in which there is no intensity information.

<span class="mw-page-title-main">Bayer filter</span> Color filter array

A Bayer filter mosaic is a color filter array (CFA) for arranging RGB color filters on a square grid of photosensors. Its particular arrangement of color filters is used in most single-chip digital image sensors used in digital cameras, and camcorders to create a color image. The filter pattern is half green, one quarter red and one quarter blue, hence is also called BGGR,RGBG, GRBG, or RGGB.

Netpbm is an open-source package of graphics programs and a programming library. It is used mainly in the Unix world, where one can find it included in all major open-source operating system distributions, but also works on Microsoft Windows, macOS, and other operating systems.

Color digital images are made of pixels, and pixels are made of combinations of primary colors represented by a series of code. A channel in this context is the grayscale image of the same size as a color image, made of just one of these primary colors. For instance, an image from a standard digital camera will have a red, green and blue channel. A grayscale image has just one channel.

<span class="mw-page-title-main">Shades of violet</span> Varieties of the color violet

Violet is a color term derived from the flower of the same name. There are numerous variations of the color violet, a sampling of which are shown below.

The Quite OK Image Format (QOI) is a specification for lossless image compression of 24-bit or 32-bit color raster (bitmapped) images, invented by Dominic Szablewski and first announced on 24 November 2021.

References