Wuhan Guide IR136 Bedienungsanleitung PDF herunterladen (Seite 79)

Thermografie in der Theorie und Praxis (INTERNET: www.irPOD.net / e-MAIL: [email protected] ) © Bernd Schindel 2007

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Object Plane

The plane created by tracing ray paths backwards from the active detector elements through the focusing

lens assembly, through the scanning mechanism to project the active field of focused image area in space.

The object plane is an optical description of what the system can focus.

Opaque

The characteristic of not passing any incident radiation (Transmissivity = 0). An optical filter is said to be

blocked in a waveband if it has less than 5% transmission over those wavelengths.

Operating Temperature Range

The range of ambient temperatures over which a system will function accurately. This range can be defined

by either a calibration limit; what range of ambient temperature offsets are allowed in the data calculations

or it can be due to a functional limit in the system; the ability to keep the detector cold or it can be set by a

catastrophic limit; batteries may not hold their charge below certain temperatures and integrated circuits will

not function above certain temperatures.

Overlap (optical)

Redundant scanning of the image field which results in multiple sets of data taken from the same image

points. If done in the direction of scan this is usually considered over sampling. If done by laying scan lines

adjacent to each other closer than the optical spot dimension, it is considered scan overlap.

Over Sampling

To take multiple sets of data redundantly. Usually indicates digitization of a signal at a rate faster than the

maximum information frequency of the data. An over sampling rate of at least two is indicated by

information theory to avoid aliasing of repetitive information.

Over Scanning

Expanding the beam deflection on a CRT so that the active viewing area is larger than the available CRT

faceplace. This cuts off the edges of the active raster. This technique is used on most television monitors.

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Wuhan Guide IR136 Bedienungsanleitung Seite 79