Photonics Dictionary: T

The graph of the oscillating variations composing the wave of a video signal.

A technique used to suppress extreme noise amplification during digital image reconstruction that relies on smoothing and differentiation of the data by simplified least squared procedures.

The Fourier series representation of a two-dimensional periodic field, assuming that the original image is periodic both horizontally and vertically.

The equivalent f number of a fictitious lens that has a circular opening and 100 percent transmittance, which would give the same central illumination as the lens being considered: where...

A device for extracting a portion of the optical signal from a fiber.

The color process that is used to form positive color cine films by dye transfer or imbibition, based on the use of separate matrices that superimpose yellow, magenta and cyan dye images on the final...

There are three types of telecentric lenses: -Image-space telecentric lenses are those in which the aperture stop is located at the front focus, resulting in the chief rays being parallel to the...

The science of sensing and measuring information at some remote location and transmitting the data to a convenient location for reading or recording.

A compound lens so constructed that its overall length is equal to or less than its effective focal length.

The ratio between the focal length of a lens having a longer focal length than that of the standard lens used with a camera, and the focal length of the standard lens. It is used to provide an...

In a telephoto lens, the ratio of the overall length to the focal length of the lens. It is generally about 0.8 to 0.9 in magnitude.

1. A method of photographing distant objects with a lens of long focal length. 2. The reproduction of photographs over a distance by means of electricity.

An instrument used to measure the luminance (brightness) of a distant object. The object is viewed through a small telescope, and a mirror in the focal plane reflects an internal illuminated surface...

The use of head-mounted displays and body-operated remote actuators to control distant machinery. Provides a virtual environment for humans to control devices, robots, etc., in a hostile real...

An afocal optical device made up of lenses or mirrors, usually with a magnification greater than unity, that renders distant objects more distinct, by enlarging their images on the retina.

A telescope lens is a primary optical component of a telescope system that gathers and focuses light to form an image. It is typically a curved, transparent piece of glass or other optical material...

To transform a picture or image field into a television signal for transmission.

The term that represents the size of one of the many small elements into which a television image is necessarily broken down for transmission.

A camera containing an electronic image sensor that converts the image to an electronic signal suitable for television applications.

A television receiver that receives the signals generated by a television camera directly, or remotely through a radio signal. It may be used to continuously check image and sound reception; as a...

The material favored for study of interaction of high-acoustic intensities with free carriers. Tellurium is the semiconductor with the largest piezoelectric constants. Tellurium oxide is the material...

Electromagnetic radiation with frequencies between 300 GHz and 10 THz, and existing between regions of the electromagnetic spectrum that are typically classified as the far-infrared and microwave...

A terahertz spectrometer is a scientific instrument used to measure and analyze the properties of materials in the terahertz frequency range, typically spanning from about 0.1 to 10 terahertz (THz),...

Terahertz (THz) refers to a unit of frequency in the electromagnetic spectrum, denoting waves with frequencies between 0.1 and 10 terahertz. One terahertz is equivalent to one trillion hertz, or...

A synonym for spatial coherence. See spatially coherent radiation.

Made up of three components; for instance yttrium, aluminum and garnet (YAG).

A telescope that produces an erect image. Erection is achieved either by a lens (for a long instrument) or a prism (for a compact instrument). Very small terrestrial telescopes of low power may be of...

A lens similar to the Cooke triplet anastigmat, with the rear crown achromatized for improved coverage and definition. It is used in medium-speed cameras and enlargers.

A device used to detect elevation, pyramid and resolution errors in prisms and other components by bringing them into contact with the three highly polished, flat, perpendicular surfaces that form...

A transparent block shaped accurately to reverse curvatures of the components it is used to test. By contacting an accurately finished negative lens shape with a newly made positive, the conformity...

A contraction for "texture element." A base unit used in computer graphics that defines the surface of three-dimensional objects. Texels are obtained from texture memory and represent color to be...

A technique for detecting free radicals by their electronic spectra. The material to be studied is placed in a temperature-controlled furnace through which radiation is propagated onto a...

Thermal interface materials (TIMs) are substances or compounds used to enhance the thermal conductivity between two surfaces in contact. These materials are primarily employed in electronic devices,...

A term referring to various processes for forming visible images outside of a camera to be photographed on ordinary film. Unlike regular infrared photography, thermal photography is an indirect...

Examination of the processes whereby heat energy is converted into other forms of energy.

An instrument that transforms heat energy into electrical energy.

The instrument used to collect thermal radiation information on an object by scanning. It consists basically of a detector, a photoconductive element that converts incident radiation to an electrical...

Thermography is a technique that involves the use of an infrared imaging device, called a thermal camera or infrared camera, to detect and visualize the infrared radiation emitted by objects. This...

An alternative term for incandescence.

Thermophotovoltaic (TPV) refers to a technology that converts heat energy into electricity using the principles of thermophotovoltaics. In a thermophotovoltaic system, thermal radiation from a heat...