SE329508B - - Google Patents

Abstract

1,181,758. Thermography equipment. BOFORS A.B. 15 Nov., 1968 [16 Nov., 1967], No. 54449/68. Heading H4F. Thermography equipment comprises an infrared camera and a cathode display tube 8, Fig, 1, scanning in synchronism and two channels in parallel connecting the output of the camera to the intensity modulation input of the display tube, a first channel comprising video amplifier 3 and providing a normal infra-red display and the second channel comprising amplifier and level detector 4 providing an isotherm display of these parts of the scene scanned having a temperature range as determined by the detection level of 4, a switch member 5 causing the channels to be sequentially switched through to the display tube, whereby the isotherm display is seen against a background of the normal display, the switching rate being slow enough for an observer to distinguish between the isotherm lines and those parts of the normal display having the same brightness. The switch member 5 may comprise a relay with a changeover contact or Fig. 2, a two contact relay-one contact being closed when the other is open and shorting the output of the particular channel to earth. When one or both displays are to be shown continuously switches 22 and/or 23 are opened. In the switching cycle of the displays the isothermal display is shown for approximately twice as long as the normal display. A time exposure photograph of the alternating displays will thus show the isotherm distinguishably brighter than any part of the normal display background.