Thermogram of incandescent, light-emitting diode (LED) and compact fluorescent (CFL) bulbs. The bulbs are rated to produce about the same amount of visible light. The LED bulb produces the least amount of wasted heat, while the incandescent bulb produces the most. Thermography is a technique for visualizing the temperature of objects by recording the thermal emission at 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.