Abstract: A method for adapting existing thermal imaging devices employing uncooled focal plane arrays (UFPA) for thermal imaging of target surfaces, the device including a housing (12) with an opening (14) for directing incident infrared rays along an optical path through an optical assembly (40) optimized to have a spectral band width of 3 to 14 um, onto a UFPA detector (48) having a spectral transmission window (84) which has a bandwidth 3 to 14 um sufficient to pass all infrared rays of interest over a broad temperature range. Filter means (44) including at least two filters (78, 80), having a band width in the ranges of 3 to 8 um and 8 to 14 um, respectively, allow for the placement of either specialized IR filter in the optical path so as to attenuate andlor pass certain wavelengths of the infrared rays depending on the specific application in a broad range between ?40° C. to 2000° C. The device allows for thermal imaging even in daytime applications in sunlight.

Abstract: A thermal imaging instrument and method is disclosed for viewing hot spots within a normally enclosed cabinet, for example, a high voltage electrical power distribution cabinet. Large and expensive thermal viewing windows normally required for thermal examination of these cabinets utilizing standard thermal imaging cameras is obviated by the use of an accessory lens assembly. The unique combination and methodology of using the lens assembly, standard thermal imaging camera and small access opening in the cabinet face allows for the retention of the safety rating of the cabinet. Further adding to the accuracy, convenience and safety of the approach, an infrared view port, together with cap and ring chain assembly, is permanently affixed to the cabinet face in relation to the small access hole. The unique combination of the instrument portion of the invention can be integrally combined in a single unit for exclusive use in detecting hot spots within a cabinet.