Photonics Dictionary: D

A cosmetic defect on the surface of an optical element. A dig is nearly equal in terms of its length and width. The size is specified numerically by its average diameter in 1/100 of a millimeter;...

Denoting the use of binary notation; i.e., the representation of data by bits (1 or 0).

A digital camera is a device that captures and records still images or video in digital format. Unlike traditional film cameras, which use photographic film to capture and store images, digital...

An instrument that can preselect intervals, often in increments of 1, 10 or 100 ns, for the generation of electronic pulses by means of front-panel switches. Also called a time-delay generator.

Pictorial information processing in which the processed picture shows a family of equidensity lines or bands coded with different printed patterns or colors.

A linear computation or algorithm performed on a selected series in the form of an input signal that produces a new series as output. The computational device may be a specifically designed...

Digital holographic microscopy (DHM) is an advanced imaging technique that combines holography and digital image processing to capture and reconstruct three-dimensional images of objects. This method...

The technique by which an analog image is converted by any of several means into a finite array of points, each represented by some numerical value. Once created, this array can be the basis of a...

Digital Imaging and Communications in Medicine (DICOM) is an international standard for medical imaging created by both the National Electrical Manufacturers Association (NEMA) and the American...

The scanning of photographs or transparencies of images, either by a vidicon camera or flying spot scanner, for the conversion of the images to digital form for storage on magnetic tape.

A form of photography in which an electronic camera converts an image to an electronic signal that is stored in digital format on magnetic media or film.

A pixel-based computer graphics system that simulates the tools of an artist.

Medical diagnostic (x-ray) imaging using laser printers to produce high-resolution digital hard copy instead of film exposed by phosphor-intensifying screens, thus providing radiologists with greater...

Digital signal processing (DSP) refers to the manipulation and analysis of signals, which are representations of physical quantities that vary over time or space. In the context of DSP, these signals...

The process by which the values of one digital image of an object or scene are removed from a second slightly different image of the same object or scene.

A digital twin refers to a virtual representation or digital counterpart of a physical object, system, or process. This digital replica is created using real-time data and simulation models, allowing...

A step-by-step method of reducing the amount of data in a digital video signal to transmit or store a high-quality image. The digitized picture is analyzed, and fine detail and redundant pixels,...

In image processing, a device that transforms the digital data into an analog video image that can be viewed on a monitor or printed.

A device that samples and quantizes a signal in digital form for storage in memory.

A hole filled with dirt such as a polishing abrasive and located in an optical surface. See dig; scratch.

A method of storing digital data using techniques that consume less memory space than basic methods do. See differential pulse code modulation; run end coding; run length coding.

Dispersion refers to the phenomenon where different wavelengths (colors) of light travel at different speeds when passing through a medium. This variation in the speed of light for different colors...