Photonics Dictionary

States that in interferometers in which the separation of the maxima is equal to the half-value width, a slight drop in intensity between fringes is distinguishable and the fringes can be considered...

In television, a lateral displacement of the lines from their normal position due to the instability of a synchronizing circuit. Visually, it appears as though parts of the images had been torn away.

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...

A passive coupler that connects three ports.

1. The term used to describe any of the many instruments used to remotely record physical dimensions, such as strain, temperature or pressure, and transmit this data to a receiving station. 2. A...

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

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 principles and techniques involved in the use of telephotometers to measure atmospheric extinction.

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...

A method of taking radiographs at a distance from the object being photographed to decrease distortion.

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.

The image of the aperture stop, usually the objective lens, that is produced by the eye lens. When the exit pupil of the telescope coincides with the entrance pupil of the eye of the observer, the...

The base used to hold an astronomical telescope. It may be either altazimuth, with horizontal and vertical axes of rotation, or equatorial, with one axis parallel to the Earth's axis of rotation and...

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.

The span of frequencies within which a single channel of broadcast television must fall; in the US, it is 6 MHz.

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

The value equal to the raster height divided by the half-period of a periodic test pattern.

A device designed to enlarge the image of a microscopic object by television process. It may be a flying spot scanner that is used to scan the microscope slide, or a camera tube-microscope...

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...

A television display system in which the television signal is converted to an image that is projected onto either a front or rear projection screen.

The combination of the audio and visual signals that are transmitted and received at the same time, correlating the scene and sound in a television picture.

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

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...

Teloscopy, while not a commonly used term, could be understood in the context of principles related to telescopes and their applications in observation and measurement. If we interpret teloscopy as...

A glass that is heated, then chilled (usually by an air blast) to set up internal stresses so that the surfaces are under compression. This strengthens the glass, since glass breaks only in tension,...

A characteristic of laser output, calculated by dividing the speed of light by the linewidth of the laser beam. The temporal coherence length of different lasers thus varies from a few centimeters to...

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.