pixels^[1] or image element^[1] (in English: Pixel) is the smallest single element in a bitmap image matrix or in image generation hardware, that is, it is the smallest that can be represented and controlled in terms of image components on screens of various technologies, and the smallest that can be scanned and stored in scanners, or in the sensor of a digital camera.

Each image pixel is a sample of the image it represents, whose properties are determined by the properties of the device sensing or generating it and by the properties of the digital representation of images in the described system.

Technically[عدل]

Depending on the context in which the term is used, a pixel can mean the symbolic representation of quantitative values ​​that describe a pixel, such as the numbers of its color components in a computer’s memory address, or the physical representation of a visible point in a hardware system on a screen.

When a pixel is used in terms of the logical description of images, the number of bits assigned to the value of each of its color components in the used color system is what determines its final color and the number of colors that can be represented in that color space. In addition to its color components, the pixel may have other properties that are determined in its logical structure, such as its degree of transparency.

The number of pixels is used as a measure of the dimensions of digital images, i.e. their length and width, and their density, i.e. their number relative to a unit of length, is used to denote the quality of images and the hardware produced for them, such as 600 pixels/cm or 300 pixels/inch.

Also, pixels may represent logical units, as in the dimensions of digital images, and then the density intended for that representation may be a required determinant in the event that an image is desired to be represented on a physical medium based on its logical description.

When converting the logical representation of the pixels into a physical representation, by displaying them on a screen, for example, the comparison between the logical pixels and the physical pixels that make up the display device may be direct, one to one, and manipulations may be made in the software and hardware to match the characteristics of the hardware and the characteristics of the image in its form. digital.

The greater the number of pixels that make up the image, the closer the digital image will be to the analogue original, and also the greater the device’s discrimination, i.e. its ability to record a digital representation that is closer to the analog reality in the eyes of the human observer, and if that is included in its determination as well as the size of the sample that estimates the device. On its record, that is, the number of bits assigned to the value of each of the colors describing the pixel. This is the result of the sampling process. sampling) in which analog phenomena are transformed into digital values, or the waveform description into quantum ((in English: quantisation)‏.

The units dpi and pixels per inch are sometimes used interchangeably, but they have a different meaning: the former is used to describe printers as a measure of the density of ink dots on a page.

Mega pixels[عدل]

megapixels It is a multiple of a pixel in an electronic image, where each million pixel represents 1 megapixel (mega = one million). This is done by multiplying the length of the image by its width if we use pixels as a unit of measure. This unit is often used to measure the area of ​​images captured by modern digital cameras. For example, if we take pictures with a length of 2048 pixels and a width of 1536 pixels, the power (accuracy) of the camera that captured it is 3.1 megapixels, meaning that this camera is able to divide the image it takes into 3.1 megapixels, and therefore the more pixels in a modern digital camera, the more accurate it is. pronounced.

The origin of the word pixel[عدل]

term pixel Arabic carving from the words “element” and “image”^{[بحاجة لمصدر]}and has been formulated in the form of the corresponding English word (in English: pixel) which is also a carving of the two English words (in English: picture) and (in English: element) Arabic sculpture appeared for the first time in Al-Uloom magazine in its issues issued in the eighties of the twentieth century.

In technical Arabic writings, phonetic localization is also used Pixel ^[2])

The term “pixel” was first used in scientific literature in 1965 by Frederick S. Billingsley to describe image elements in a video taken of the surface of the Moon and Mars. However, Billingsley did not coin the term, rather he took it from Keith E. McFarland who was working in the Palo Alto laboratory, who stated that he did not know the exact source of the word until it had been in use since about 1963.

Following this derivation pattern, other terms were later derived to describe the smaller data units that describe types of information, so we find:

Texel

It is an element of an image used as a coating (the English name is derived from the two words texture element).

voxel

Carving from the words volumetric and pixel, any volumetric element, and represents a cube or a point of a certain color in a three-dimensional object. A voxel is an element in a three-dimensional object, just as a pixel is an element in a two-dimensional surface.

See also[عدل]

• Bitmap graphics
• pixel art
• voxel
• Picture Resolution
• Image histogram

Resources[عدل]

external links[عدل]

In Commons, photos and files for: pixel

• A broader pictorial explanation of pixels

• Digital photo portal
• Photography portal
• Computer graphics portal

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