scan (redirected from ventilation-perfusion scan)

scan

(1) To make an electronic comparison of a signal, pixel or data structure as described in the following definitions.

(2) In optical technologies, to read a printed form a line at a time in order to convert images into bitmapped representations or convert characters into text. See OCR.

(3) In video, to move across a picture frame a line at a time, either to detect the image in an analog or digital camera, or to refresh a CRT display.

(4) To search a data file sequentially for specific content.

(5) To search an executable file for a particular pattern. See antivirus program.

(6) To sequentially search for peripheral devices attached to the computer.

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scan

Med

a. the examination of a part of the body by means of a scanner

b. the image produced by a scanner

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scan [skan]

(computer science)

To examine information, following a systematic, predetermined sequence, for some particular purpose.

(electronics)

The motion, usually periodic, given to the major lobe of an antenna; the process of directing the radio-frequency beam successively over all points in a given region of space.

(engineering)

To examine an area, a region in space, or a portion of the radio spectrum point by point in an ordered sequence; for example, conversion of a scene or image to an electric signal or use of radar to monitor an airspace for detection, navigation, or traffic control purposes.

One complete circular, up-and-down, or left-to-right sweep of the radar, light, or other beam or device used in making a scan.

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1.		SCAN - ["A Parallel Implementation of the SCAN Language", N.G. Bourbakis, Comp Langs 14(4):239-254 (1989)].
2.		SCAN - A real-time language from DEC.
3.		scan - (computer peripheral) See scanner.
4.		scan - (circuit design) See scan design.
5.		scan - (functional programming) See scanl, scanr.
6.	(storage, algorithm)	scan - An algorithm for scheduling multiple accesses to a disk. A number of requests are ordered according to the data's position on the storage device. This reduces the disk arm movement to one "scan" or sweep across the whole disk in the worst case. The serivce time can be estimated from the disk's track-to-track seek time, maximum seek time (one scan), and maximum rotational latency. Scan-EDF is a variation on this.