Research On Anechoic Chamber Quiet Zone And Counting PMMW Metal Targets

Millimeter wave (MMW) spectrum is between microwave and infrared, and has both common characteristics of microwave and infrared, and has its characteristic. Domestic and overseas scholars have paid great attention to the MMW and dedicated to the research and developed a new frequency band.Millimeter wave technology has important application prospect in these domains: precision guidance of missile, the detecting of military targets, resources remote sensing, communication and medical treatment.The main assignments of this paper include two contents.Firstly, this paper had analyzed the performance of anechoic chambers where the simulation environment of missile precision guidance. A model of geometrical optics and energy integral was established based on the requirement of anechoic chamber performance for missile guidance simulation. If the quiet zone total power that gets from all walls divided by the power that gets directly from source signal is less than or equal to 0.03, we consider this model is up to the mustard of simulation requirements. Otherwise we consider it is not up to the mustard of simulation requirements. This paper introduces geometrical optics and energy integral to establish anechoic chamber evaluate model. We have analyzed the reflection of electromagnetic waves in wedge-shaped absorbers from the principle of geometrical optics. The relation between wedge-shaped top angle and reflectivity, reflectivity frequency was presented. The method of quiet zone energy integral calculation was presented. It simplifies the complexity of Maxwell’s equation and improves the efficiency of engineering computing. The result is more valuable than traditional methods.Secondly, this paper had analyzed the way to enhance PMMW images’definition under the condition of low resolution. The method of mathematical morphology is proposed to process the image. The Canny operator is used for detecting the edge of image and extracting image edge. This paper overcomes the problem that counting the number of targets automatically. A counting system was developed by Visual C++6.0 tool to count the number of metal targets.Chapt.1 reviews the application background of MMW and traces down the latest development of MMW. It includes MMW guidance of missile precision, the simulation environment of missile (anechoic chamber) and the principle of detecting metal targets by PMMW. In chapt.2, the model of geometrical optics and energy integral was established which based on the requirement of anechoic chamber performance for missile guidance simulation. Chapt.3 analyses the program of PMMW image processing and gives the scheme of processing. Chapt.4 uses pixel label algorithm to set up PMMW metal targets counting system and tests the system.There are some creative points in this paper:1. This paper gives the relationship between the top angle and reflectivity, reflectivity frequency from geometrical optics model. Also, an improved model is presented on the basis of geometrical optics (Chapt.2).2. This paper adopts energy integral calculation to replace the conventional solving means that based on Maxwell equation. The energy integral reduces the amount of computation and complexity and enhance engineering computing efficiency (Chapt.2).3. This paper was firstly tried to present a detailed process processing with PMMW for the PMMW imaging that was in low resolution currently (Chapt.3).4. This paper was firstly tried to establish a system which was used for calculating the number of metal targets in PMMW images. Currently methods of recognizing and counting automatically the number of metal targets in PMMW images is lacking.