Thermal imaging experiments of motor vehicles under low visibility at night

Abstract

A low atmospheric visibility environment is artificially set up to test the thermal imaging characteristics of heave duty truck, middle-sized truck and microbus under different visibilities and states by a thermal imaging system at night. By the experimental results, all thermal images of various motor vehicles are very clear under high atmospheric visibility whether the vehicle is started or not at night while the started motor vehicle is easier to distinguish from the environment than the not started one. For started motor vehicles, the characteristic temperature is distributed at engine and tail gas emission tube. The highest temperature appears on the surface of engine and it is greatly higher than other parts of the motor vehicle. By the experiment, the average imaging temperature of motor vehicle body is hard to be affected by visibility while the characteristic imaging temperature of engine is observably affected by low visibility. The lower the visibility is, the more illegible the thermal image is. Especially, the highest imaging temperature decreases quickly and falls toward the environment's temperature. Under very low visibility, the imaging temperature of character position is still greatly higher than the average temperature of motor vehicle body or environment although the thermal image of the whole motor vehicle body is illegible. As a result, any started motor vehicle may be found, scouted or traced by locking the highest imaging temperature at engine part under low atmospheric visibility with a thermal imaging system.