本文關(guān)鍵詞：穿墻三維成像技術(shù)研究　出處：《國防科學(xué)技術(shù)大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 穿墻雷達(dá) 三維成像 多輸入多輸出陣列 虛擬陣列 因式分解快速后向投影算法

【摘要】：穿墻成像雷達(dá)(Through-Wall Imaging Radar,TWIR)利用低頻電磁波的穿透特性,對隱蔽在建筑物之內(nèi)的目標(biāo)進(jìn)行探測、定位和成像等狀態(tài)分析,大大提高了城區(qū)作戰(zhàn)能力、反恐斗爭以及災(zāi)難救援時人員搜救能力,成為了近些年來的研究熱點。由于二維成像是對真實三維空間二維投影的結(jié)果,成像結(jié)果不可避免地會出現(xiàn)定位誤差、陰影效應(yīng)以及空間模糊等現(xiàn)象,獲取目標(biāo)場景的三維信息成為了迫切需要。本文圍繞穿墻三維成像問題,對穿墻三維成像基礎(chǔ)、穿墻二維多輸入多輸出(Multiple Input Multiple Output,MIMO)陣列設(shè)計以及介質(zhì)穿透三維圖像快速重建三個主要問題進(jìn)行了分析研究。首先分析了三維成像中目標(biāo)空間、數(shù)據(jù)空間和圖像空間與成像過程的對應(yīng)關(guān)系,建立了步進(jìn)頻信號體制的三維回波模型;具體分析了三種常見時頻域三維成像算法,并針對介質(zhì)穿透成像的特點選取時域后向投影(Back Projection,BP)算法作為基本穿墻成像算法;通過角度旋轉(zhuǎn)變換方法將二維空間中的傳輸路徑的求解方法應(yīng)用于介質(zhì)穿透三維成像中,建立了介質(zhì)穿透三維成像模型。其次在分析寬帶稀疏陣列柵瓣特性和二維面陣中高度向、方位向陣元分布對相應(yīng)方向陣列性能的相互影響的基礎(chǔ)上,利用虛擬等效陣列的思想,提出一種基于子陣劃分的普適性二維平面MIMO陣列設(shè)計方法。該方法可得到多種典型MIMO陣列架構(gòu),利用子陣劃分信息可從中選擇出具有最小物理尺寸的MIMO陣列。仿真實例驗證了該設(shè)計方法,取得了較好結(jié)果。最后分析了二維因式分解快速后向投影(Fast Factorized Back Projection,FFBP)算法的基本原理、距離誤差以及成像效率等問題;建立了適用于FFBP算法的方位、高度向等效的三維極坐標(biāo)系,將二維FFBP算法推廣至三維成像,推導(dǎo)出適于介質(zhì)穿透的三維FFBP算法,并對介質(zhì)穿透條件下傳統(tǒng)BP算法與三維FFBP算法性能以及成像結(jié)果進(jìn)行了對比分析,證明了三維FFBP的有效性和魯棒性。
[Abstract]:Through-Wall Imaging Radarr (TWIR) detects targets hidden in buildings by using the penetrating characteristics of low-frequency electromagnetic waves. State analysis, such as positioning and imaging, has greatly improved the city's combat capability, the ability to search and rescue people in the fight against terrorism and in disaster relief. In recent years, two-dimensional imaging is the result of 2D projection of real three-dimensional space, which inevitably leads to localization error, shadow effect and spatial blurring. It is an urgent need to obtain 3D information of target scene. Two dimensional multiple Input Multiple Output through the wall. The three main problems of MIMO-array design and fast reconstruction of media penetrating 3D image are analyzed. Firstly, the target space in 3D imaging is analyzed. The relationship between the data space and the image space and the imaging process, the three-dimensional echo model of the stepping frequency signal system is established. Three common 3D imaging algorithms in time-frequency domain are analyzed in detail. According to the characteristics of dielectric penetrating imaging, the time-domain backward projection back Projection is selected. BPalgorithm is used as the basic imaging algorithm. The method of solving the transmission path in two-dimensional space is applied to the three-dimensional imaging of media penetration by the method of angular rotation transformation. The 3D imaging model of dielectric penetration is established. Secondly, based on the analysis of the characteristics of the wide band sparse array gate lobe and the interaction between the height and the azimuth distribution of the array in two dimensional plane array, the performance of the array in the corresponding direction is analyzed. Based on the idea of virtual equivalent array, a universal two-dimensional planar MIMO array design method based on subarray partition is proposed, which can be used to obtain several typical MIMO array architectures. The MIMO array with the minimum physical size can be selected from the subarray partition information. The simulation example verifies the design method. Good results have been obtained. Finally, fast Factorized Back Projection with fast backward projection of 2-D factorization is analyzed. The basic principle, range error and imaging efficiency of FFBP algorithm are discussed. The azimuth and height equivalent three-dimensional polar coordinate system suitable for FFBP algorithm is established. The two-dimensional FFBP algorithm is extended to 3D imaging and a three-dimensional FFBP algorithm suitable for medium penetration is derived. The performance and imaging results of traditional BP algorithm and 3D FFBP algorithm under the condition of medium penetration are compared and analyzed. The effectiveness and robustness of 3D FFBP are proved.
【學(xué)位授予單位】：國防科學(xué)技術(shù)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN957.52

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