Photonics Dictionary: T

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...

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

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

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...

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...

Also known as analog thermogram. The resultant photograph, illustrating, in tones ranging from black to white, the spatial relationship of the infrared radiation temperatures of the different details...

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...

A type of holographic film widely used for industrial applications because it is inexpensive and erasable.

Multiple exposures of holograms, one for each position of a vibrating image, that are used for vibration analysis and that yield a record of the time-averaged irradiance distribution at the hologram...

Although low in sensitivity (approximately 10-7 m for helium-neon lasers), this holographic technique permits quantitative assessment of entire vibratory patterns of given structures in a single...

Time-lapse optical coherence tomography (OCT) refers to a medical imaging technique that captures a series of sequential OCT scans over time, allowing for the dynamic observation and monitoring of...

Technique that defocuses activity from surrounding planes by means of the relative motions at the point of interest.

A variation of tomography in which several photographs of a patient are taken at different angles, and back-projection of the resulting radiographs produces light distribution in a chosen...

A method of measuring total hemispherical emissivity of the plane surface of a solid that consists of thermally isolating a specimen of the material inside a vacuum, preheating it slightly above the...

A transmission electron microscope (TEM) is a powerful microscopy technique that uses a beam of electrons to create high-resolution images of extremely thin samples. In a TEM, electrons are...

An image affixed to a transparent photographic film or plate by photographic, printing or chemical methods. It may be viewed by transmitted light.

Imaging materials that generally consist of a polyester base, a transparent electrically conductive layer and an organic photoconductive top coating. When charged and exposed to light, an...