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An infrared camera, or more specifically, a thermal count IE or a thermal image camera, is similar picture-witnessing equipment, which than data source uses infrared radiation, to a conventional camera, which uses the visible flash spectrum (380-750 Nm) for the production of pictures however. The infrared radiation used by the infrared camera lies against it in the wavelength coverage of 0,7 - 1000 The majority of the commercial infrared cameras uses however only the spectral region of 3,5 - 14 (centralwavy and long-wave IR).
In this wavelength coverage the influence of sun exposure and light is smaller than in shorter-wave range thus is this range preferably for the measurement of temperatures in the Umgebugstemperaturbereich suitable. The normal atmosphere is in this range due to their composition to a large extent transparency.
To produce by means of an infrared or a Thermografiekamera of pictures one calls the procedure Thermografie. Thermografie is a picture-giving procedure, which makes the radiant heat (infra-red light) of an object or a body invisible for the human eye visible. The Thermografie is a contactless measuring procedure, i.e., it can also extremely high-speed procedures (explosions, burns etc.) and courses of motion be seized. With the help of the Thermografie temperature measurements can be seized and represented
Each object (with a temperature above the absolute zero) sends a certain quantity of radiant heat. These material emitters in such a way specified emit however only one part of the radiation of a black body. The deviation of the material temperature emitter from the black body is defined by the emission coefficient (or emissivity). It depends on the material, the surface finish, the temperature and the wavelength. The influence of the temperature on the emission coefficient can with measuring tasks in the middle temperature range of e.g. 0"°C to 100"°C to be in most cases neglected. The moreover one many materials within the long-wave IR range possess an emissivity almost independent of the wavelength.
Pictures, which are produced by infrared cameras, are usually mono chrome, i.e. divides into gray tones. Usual camera models are able to represent up to 256 gray tones. Color has less meaning outside of the visible spectral region. However it is useful for the human viewer to receive colored pictures why nearly all usual IR camera types are able, the produced pictures with wrong colors to represent. It is in the so dyed picture a change of the indicated color, not only a change of the grey intensity, which refers to a thermal anomaly. For the dye of the monochromen pictures usually different Farbpaletten are available. Often the brightest (warmest) part of the picture is represented white, the intermediate temperatures in yellow and red tones and the dark (colder) parts of the picture in blue tones.
The geometrical dissolution of commercial Thermografiekameras is considerably lower than with optical cameras, typically 160 x 120 and/or 320 x of 240 pixels. This determines the smallest detectable measuring mark of the Thermografiesystems in interaction with the assigned objectives and/or the visual field (=Field OF View) of the camera.
Typical operational areas for Thermografiekameras within the civilian range are seeking out glow nests with fires or the search for persons in smoked buildings or with darkness by the fire-brigade, the preventing maintenance by examination of electrical and mechanical plants, leakage detection in pipings or under-floor heatings, building diagnostics (thermal insulation, energy passport), as well as process and production supervision.
Thermografiekameras can be divided into two kinds: Systems with cooled infrared picture detectors and with uncooled detectors.
Cooled detectors are accommodated and kryogenisch are usually cooled in a vacuum-sealed housing. The work temperature of the detectors is thereby typically between 4 K (Kelvin) and 110 K, whereby the most usual value is with approx. 80 K. Thus the detectors are usually much colder than the objects which can be observed, whereby the thermal sensitivity (dissolution of temperature) of the Thermografiesystems increases in relation to the uncooled systems crucially. A disadvantage of this method: If the cooling of the detector precipitates, the Thermografiesystem is blind "".
Further disadvantages of cooled systems are the increased acquisition and operating cost, as well as those every now and then are enough for starting time, until the system down cooled the detector on operating temperature.
Opposite the outstanding image quality stands compared with uncooled systems.
The infrared detectors of cooled systems can consist among other things of the following materials:
Uncooled Thermografiekameras uses detectors, those with ambient temperature works or by small temperature regulator units close at ambient temperature to be stabilized. All modern uncooled systems work according to the principle of the change of resistance, tension or amperage at heating of the detector by the infrared radiation. These changes are measured and compared with the values with operating temperature. From this the taken up radiation dosage (and thus the temperature) is determined.
Uncooled infrared sensors are stabilized with a certain operating temperature, in order to reduce the signal noise, but they are not cooled down on low temperatures. Therefore such systems without expensive, unmanageable cooling devices get along. Thus this Thermografiesysteme is clearly smaller and more economical than the cooled systems.
However these systems are inclined to supply a result worse compared with cooled systems.
Uncooled detectors are mostly based on pyroelectric materials or micro bolometer technology.
Originally for the military use during the Korea war developed, Thermografiekameras are to be found today in many operational areas. The development of new technologies and the associated price purge with the Thermografiesystemen led substantially to the spreading of this technology. The improvement of the assigned objectives and the development of professional software programs for analysis and report production extend the application type of the infrared Thermografie sequentially. Typical operational areas are today among other things:
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