20 January 1976 The Thermo-Liner - An Instrument For Thermal Inspection
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Infrared thermography has become an accepted technique for nondestructive testing and thermal inspection problems . Such applications often require knowledge of the temperature distribution over a localized area and much of a thermal picture is extraneous, useful only to position the field of view or locate the desired regions of interest. A battery operated hand-held viewer is described which superim-poses a graph of the temperature distribution along an indicated line, onto a direct visual image of a two-dimensional field. This is accomplished by an oscillating dichroic mirror, one side of which produces an infrared, single-line scan with a pyroelectric detector, while the other side causes an orthogonal array of 18 red LED's to scan across the field of the observer. The oscillating mirror is transparent in the blue-yellow spectral region so that the viewer sees the red diode array superimposed onto a blue-yellow visible image of the field. Appropriate LED's in the array are switched on depending upon the amplitude of the infrared signal, to generate the thermal profile or graph. Temperature variations down to 0.2°C can be accurately measured with a spatial resolution of 4 mrad. The operator observes the scene through the view-finder of a reflex camera, and can make a film recording of the subject and thermal profile at any time. Applications to field, and in-plant, thermal inspection will be illustrated.
© (1976) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Robert W. Astheimer, Gerald Falbel, "The Thermo-Liner - An Instrument For Thermal Inspection", Proc. SPIE 0062, Modern Utilization of Infrared Technology I, (20 January 1976); doi: 10.1117/12.954448; https://doi.org/10.1117/12.954448

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