Experimental Study Of The Surface Features And Target Near / Shortwave Infrared Reflectance Characteristics In The Natural Environment

Near/shortwave infrared radiation is common in natural environment, different targets and backgrounds on the ground show different degree of light and dark. It provides a physical basis for near/shortwave infrared passively detecting ground target. Based on the development of near/shortwave infrared passive target detection method, near/shortwave infrared radiometer has been designed, processed and debugged. And near/shortwave infrared radiometer as the core components of the target light reflectance measurement device has been established. Experimentally, the changes of near/shortwave infrared light intensity on the ground in a day, and the influence in different time and ambient light on the optical power of reflected light received by radiometer receiver have been studied. A large number of experiment data about the near/shortwave infrared radiation in natural has been accumulated. On this basis, the angular reflectances of typical simulate targets and backgrounds at the wavebands of 808nm,905nm,1550nm and 1000-1550nm have been measured in different weather, different pitch angles and different azimuth angles. The results show that (1)in the near/shortwave infrared waveband the angular reflectances of typical simulate targets which we used in the experiment is lower than that of backgrounds; (2) the angular reflectances of artificial target is higher than that of backgrounds; (3) the reflectance increases as the wavelength increases; (4)the difference of the reflectance between target and background reaches the maximum in the length of 905nm, it provides the direct experimental evidence for designing the near/shortwave infrared passive detection device. In addition, the paper also proposed the passive scanning detection scheme by near/shortwave infrared radiometer, and the establishes one dimensional simulation model of near/shortwave infrared scanning radiometer. Simulation test gets the one-dimensional passive intensity image when the near/shortwave infrared radiometer scans the target in typical condition. The conclusion in this paper owns a certain value to study the near/shortwave infrared passive target detection method.