Visual Range Evaluation Of LLL Night Vision System With Laser Illuminator

Night vision technique, by which the eye vision can be opened up, has been developed rapidly and used widely since it appeared in 1930s. LLL night vision system depends on the night sky light illumination conditions, i.e., at a passive work mode. It can stay in concealment. However, it is influenced greatly by nature light illumination and atmosphere transparence so that the image got from it is not very clear. In order to improve detecting distance of the night vision system, a LLL night vision device with laser illuminator has been studied, which reserves the advantage of the passive device and extends visual range, especially under the atrocious weather. So it can be used to equip the army and to narrow the gap between domestic and foreign country.In this paper, LLL night vision device has been studied in a systematic way, the apparent distance detecting equation has been revised, the visual simulation on the system has been made and the theoretical calculations and experimental data on night vision goggle for driver have been analyzed. It has important reference value either for designing a system or for estimating performances.The content of every chapter in this dissertation is summarized as following:In chapter 1, the developing history and present situation of LLL night vision system were reviewed. The actuality and tendency of LLL imaging technology in domestic and developed country were described. The research intention, signification were expatiated.In chapter 2, the research intention and design principle of CY-1C night vision goggle were explained which filled the gaps in active-passive combined night vision field in our country. The structure, composition, mechanism and overall performances were analyzed in detail.In chapter 3, night sky spectral distribution, laser spectral distribution and its attenuation in the atmosphere, the characteristics of reflection spectrum of objects were studied. The spectral matching factors of typical photo cathodes for reflecting spectrum of objects were deduced and analyzed, which were the base of the detecting distance evaluation.In chapter 4, the fundamental conception about visual range of LLL imaging system with laser illuminator was described. Based on the common apparent distance detecting equation, a more practicable and reliable detecting equation was established by using the factors, such as luminance gain, spectral matching factor, etc. The relations of parameters that have an influence on performances of system were analyzed.