Scanner

A scanner is a technological device which acquires information from the world and converts it into data, often to be analyzed or stored by a computer.

In the context of general computing, a scanner is a device which analyzes a physical image (such as a photograph, printed text, or handwriting) and converts it to a digital image. See scanner (computing).

There is also another type of scanner that is used generally for receiving radio broadcasts above 30Mhz. They are illegal in some states and countries.

In computer networking, a scanner is a computer program to probe a remote system, typically to discover a vulnerability. See vulnerability scanner.

See also:

• MRI scanner
• CAT scan
• Medical ultrasonography
• Positron emission tomography

Scanning

In telecommunication, the term scanning has the following meanings:

1. In telecommunications systems, examination of traffic activity to determine whether further processing is required.

Note: Scanning is usually performed periodically.

2. In television, facsimile, and picture transmission, the process of successively analyzing the colors and densities of the object according to a predetermined pattern.

3. The process of tuning a device through a predetermined range of frequencies in prescribed increments and at prescribed times.

Note: Scanning may be performed at regular or random increments and intervals.

4. In radar and radio direction-finding, the slewing of an antenna or radiation pattern for the purpose of probing in a different direction.

Note 1: In radar, scanning may be mechanical, using a rotary microwave joint to feed the antenna, or electronic, using a phased array of radiators, the radiated pattern (beam) of which depends on the relative phases of the signals fed to the individual radiators.

Note 2: In civilian air traffic control radar, scanning usually implies continuous rotation of the antenna or beam about a vertical axis. In military radars, scanning may occur about other than a vertical axis, and may not encompass a full 360°.

Scanning is also a term for the medical technique for body imaging.

Scan

In telecommunication, the term scan has the following meanings:

1. To examine sequentially, part by part.

2. To examine every reference in every entry in a file routinely as part of a retrieval scheme.

3. In radar, one complete rotation of the interrogating antenna.

4. In SONAR, to search 360° or a specific search sector by the use of phased array of transducers.

5. To sweep, i.e., rotate, a beam about a point or about an axis.

Source: from Federal Standard 1037C in support of MIL-STD-188