Radiative heat transfer (thermogram). Shown here is a thermogram of an incandescent lamp shining on a piece of black cardboard. Radiative energy heats up the cardboard thus raising its temperature. Because cardboard is a relatively poor heat conductor, the temperature increase is not uniform. Thermography is a technique for visualizing the temperature of objects by recording the thermal emission intensity at long infrared wavelengths. This image was acquired with a specialized camera that uses a focal-plane array of vanadium oxide microbolometers as a sensor. It is sensitive to electromagnetic radiation in the wavelength range of 8 to 14 micron. The camera produces a 320x240-pixel image where different colors correspond to different temperatures.