thermography

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thermography

(thûr'mŏg`rəfē), contact photocopying process that produces a direct positive image and in which infrared rays are used to expose the copy paper. In a specially designed machine the original is placed in contact with a copy paper containing a heat-sensitive substance. As the infrared rays produced in the machine impinge on the dark or printed regions of the original, the heat generated is transferred to the adjoining areas of the sensitive paper. These areas become dark as well, creating an image of the original. As infrared rays are difficult to focus, the image formed is lacking in sharpness, resolution, and detail. The copies remain sensitive to heat, so that they may darken further with age. The advantages of this process are that it is low in cost and fast and can be performed with simple equipment.

Thermography

 

(1) In the broad sense, the recording of the heat field of objects—that is, the field of their infrared radiation.

(2) See (in photocopying).


Thermography

 

(in photocopying), a copying process based on the ability of heat-sensitive materials to change their state under the action of heat—in this case, infrared radiation. In the case of direct, or thermochemical, copying, copies are made by the contact method on thermal copy paper, using transillumination or reflected radiation. In transfer copying, copies are produced on a copy base, using thermal copy paper or film. In both cases, copies may be made from originals in india ink or black pencil or from typewritten or typeset material; the elements of such originals are capable of intense absorption of heat.

Upon exposure to infrared radiation, the light—that is, blank—portions of the original reflect most of the rays, whereas the dark portions absorb the rays and thus are heated. In contact thermography, heat from a heated element of the original causes a chemical reaction in the sensitive layer of the thermal copy paper, with which it is in contact, resulting in the formation of a dark contrast substance. In transfer thermography, the sensitive layer of a thermoplastic film or thermal copy paper melts under the action of heat and is transferred to the copy base.

Copies on thermal copy paper darken with time as a consequence of the action of heat and light on the nonprinting elements, which remain heat-sensitive; therefore, the storage life of such copies is limited. Thermoplastic copying makes possible the production of printing plates to be used in small-job printing; in addition, it makes possible the production of copies for prolonged storage.

REFERENCE

Alferov, A. V., I. S. Reznik, and V. G. Shorin. Orgatekhnika. Moscow, 1973.

A. IA. MANTSEN

thermography

[thər′mäg·rə·fē]
(engineering)
A method of measuring surface temperature by using luminescent materials: the two main types are contact thermography and projection thermography.
(graphic arts)
A photocopying process in which the original copy is placed in contact with a transparent sheet and is exposed to infrared rays; heat from carbon or a metallic compound in the text ink then causes a chemical change in a substance laminated between the transparent sheet of paper and a white waxy back.
Photography that uses radiation in the long-wavelength far-infrared region, emitted by objects at temperatures ranging from -170°F (-112°C) to over 300°F (149°C). Also known as thermal photography.
(medicine)
A medical imaging technique based on detection of heat emitted by the body.

thermography

The process of converting temperature changes of a scanned scene into a visual picture.
References in periodicals archive ?
However, intrinsic limitations of airport thermal scanners are that passengers have to become symptomatic before disembarking from a flight and have a fever high enough to be detected.
Singapore's Changi international airport has set up a total of 15 thermal scanners at its three terminals to screen passengers on flights arriving from all destinations, said a joint statement from the Civil Aviation Authority of Singapore and the Health Ministry.
Nearly all federal district, appellate and state courts that have dealt with the issue of whether use of a thermal scanner constitutes a search have held that it does not.
Thermal scanners were installed in airports to check the body temperature of incoming tourists, especially those from Zika-afflicted countries.
Islamabad are equipped with thermal scanners, that are capable to detect person suffering from fever and flu, extremely important as these are included among the symptoms of Ebola, and people arriving in Pakistan
Airports like Delhi and Mumbai, for instance, have thermal scanners to detect if someone is running a fever has landed without disclosing possible Ebola symptoms.
Two momarsa for the maintenance of (a) 40 thermal scanners, also (b) supply of 2 million shots of a three stage vaccine.
He said two thermal scanners have been fitted at two locations in the airport to detect travellers with C H1N1 symptoms.
Schools will be likewise provided with thermal scanners to bolster its detection capabilities.
Four thermal Scanners had been installed at the Indira Gandhi International Airport, Delhi on a pilot basis.
Thermal scanners were in place in several Asian countries checking passengers arriving from North America, and doctors were going on board arriving flights in Japan and Taiwan looking for signs of fever.
In addition, 763,082 persons (467,870 inbound and 295,212 outbound) were screened by the thermal scanners (Table 2).