Objective With the rapid development of infrared detection system in military war and aerospace, it is very important to evaluate the performance of infrared detection system quickly and accurately. The system test in the real environment will increase the cost of human and material resources, and will also result in poor repeatability of test results and long test cycle due to the impact of external environment and terrain factors. Therefore, the method of infrared hardware-in-the-loop simulation based on infrared dynamic target simulator can effectively reduce the test cycle and test cost, and improve the stability of test results. At present, it mainly adopts the infrared imaging technology based on digital micro-mirror device (DMD), but the core devices of this technology are monopolized by foreign countries. Only by replacing the visible light DMD chip window, which is a complex method, can it be applied in the infrared band. Its processing technology is quite complex, which also hinders its further development. Besides, the size of DMD micro-mirror is 13 μm, which is similar to the wavelength of long-wave infrared, strong diffraction will be generated, so the infrared dynamic scene with high resolution and high contrast cannot be produced. Based on the current development, the micro-radiation array chip is designed and prepared. By converting visible light into infrared radiation, the infrared dynamic scene can be simulated with high resolution, high frame rate and wide temperature range. At the same time, the infrared dynamic scene simulation system prototype is built with this as the core device, in combination with multiple infrared shaping lenses and large aperture horizontal light tubes, which can cover conventional infrared imaging equipment, and realize high-quality dynamic scene simulation in two bands of medium and long-wave infrared. Semiconductor laser is used instead of traditional light source mercury lamp on the light source to effectively improve the simulation performance of the system, the simulated temperature difference is more than 50 K, the contrast is more than 3∶1, and the frequency is more than 80 Hz.
Methods In this paper, an infrared dynamic scene simulation system based on micro-radiation array is established. The system (Fig.1) is composed of visible light projection system, infrared micro-radiation array (Fig.3), vacuum packaging system (Fig.7) and infrared lens. A theoretical model of micro-radiation array was established through heat transfer equations, and simulation experiments were conducted. By comparing the high-power semiconductor laser with the traditional mercury lamp light source, the high-power semiconductor laser is finally used as the system light source to effectively improve the contrast of the system. After analyzing the optical system, a set of complex battlefield environment infrared scene simulation and verification system based on micro-radiation array is formed after vacuum packaging. Through the whole system test (Fig.15), it can achieve high-quality dynamic scene simulation in the two bands of medium and long-wave infrared.
Results and Discussions The infrared dynamic scene simulator (Fig.2) based on the micro-radiation array (Fig.3) can conduct infrared imaging in the medium wave (Fig.8) and long wave (Fig.11) through the analysis of Zemax software, and has been applied in the infrared simulation system. High-power semiconductor laser is used to replace the traditional mercury lamp light source to improve the test performance of the system. The simulated temperature difference is more than 50 K and the contrast is more than 3:1. Especially in the long-wave infrared band, it has high contrast, which makes up for the disadvantage of the low contrast in the long-wave band of the DMD system and the resolution can be further improved. The imaging results are shown (Fig.16), dynamic images can be clearly simulated.
Conclusions The theoretical model of micro-radiation array chip is established by heat transfer equation, and the lighting optical system and mid-wave and long-wave infrared system are designed. After vacuum packaging of the chip, the infrared scene simulation verification system based on micro-radiation array is composed. This system has simple structure, its array resolution can be further improved according to the target simulation requirements, and the cost is low. At the same time, frame frequency is limited by the heat conduction efficiency of the chip due to passive radiation. The experimental results show that the system can convert visible image into infrared image, the simulated temperature difference is greater than 50 K, the contrast is greater than 3:1, and the frame frequency is greater than 80 Hz, which verifies the feasibility of infrared simulation technology based on micro-radiation array.
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