| abstract |
A beam of infrared energy, directed onto an incremental area of a surface of an article to heat the area, is scanned in a predetermined pattern across the surface of the article. As the beam scans across the surface, the thermal response of two or more scanned incremental areas, adjacent to the heated area, is detected, and electrical signals are generated in accordance therewith. The electrical signals are applied to individual inputs of a multi-gun cathode ray tube, the electron beams of which are scanned in the predetermined pattern, and in the same spatial relationship as the detected incremental areas, throughout their entire raster, to generate on the screen thereof a thermal diffusogram of the surface of the article. |