Passive Millimeter Wave Image Super-resolution Reconstruction And Enhancement Technology Research

Passive millimeter wave (PMMW) imaging technology makes use of the difference of radiant energy in the millimeter wave band between the target and background. Compared with infrared imaging, as millimeter wave can pass through clouds, dust and general textiles, millimeter wave imaging system not only has the ability to work at all-time and in all-weather but also has some anti-camouflage capability. It can be widely used in maintenance of stability against terrorism,aviation security,ground monitoring,military reconnaissance and other areas. However, millimeter wave images have low-resolution and are often blurred. So, millimeter wave image must be enhanced to obtain clear edges before image fusion, target detection and recognition. Supported by National Natural Science Foundation of China, passive millimeter wave image resolution enhancement technology has been explored and investigated in this dissertation, the main contents are as follows:1. The basic principles of passive millimeter wave imaging technology and the receiver principles of millimeter wave radiometer have been analysised. Then the mathematical model of passive millimeter wave imaging has been deeply analysised.2. Enhance passive millimeter wave image with statistical optimization-based super-resolution algorithms. Because the traditional super-resolution algorithms have a problem of slow convergence rate and maybe affect real-time imaging, exponential function is used to speed up these algorithms.3. Partial differential equations are used to process passive millimeter wave images. Total variation image restoration algorithm, heat diffusion, shock filter, P-M diffusion process and adaptive bidirectional diffusion have been deeply explored. The relevant simulation experiments are completed. And the results of simulation experiments show that adaptive bidirectional diffusion algorithm can effectively remove noise, sharpen edges and enhance image resolution, which is the best algorithm to PMMW image enhancement. 4. Numerical solution of partial differential equations has been deeply studied. Gradient descent flow is used to solve PDEs, and flux limited technology is used to prevent overshoot generated by the shock filter.