【摘要】：出于維穩(wěn)、偵查和救援等需要,穿墻雷達技術(shù)逐漸成為研究熱點。建筑物透視探測場景成像技術(shù)以穿墻雷達成像技術(shù)為依托,主要實現(xiàn)建筑布局成像和隱蔽目標成像兩個功能,分別用來形成建筑布局全景圖像和隱蔽目標圖像。穿墻雷達合成孔徑成像技術(shù)按探測模式可以分為條帶SAR模式和聚束SAR模式。傳統(tǒng)條帶SAR模式多采用多視角探測,但實際應用的環(huán)境復雜性通常不具備多視角探測的條件。另外,電磁信號穿墻傳播引起的信號強度衰減帶來建筑布局成像強度的非均勻性,這為最終建筑布局的檢測和獲得帶來了較大的困難。再者,在建筑物的封閉探測環(huán)境中,墻體造成的目標多徑回波干擾嚴重,成像過程中產(chǎn)生大量的多徑幻象,無法形成高質(zhì)量的隱蔽目標圖像。本文針對以上這些問題,做了以下工作:1、針對車載聚束SAR模式能在單一視角一次性完成場景成像,適合復雜環(huán)境下探測的特點,研究了車載聚束SAR模式的信號模型,給出該模式下的RMA和BP成像算法;2.提出一種基于模糊邏輯的PCA圖像增強方法,有效抑制雜波和噪聲并增強了建筑布局圖像強度,實測數(shù)據(jù)處理驗證了算法的有效性;3.提出一種基于霍夫變換門限檢測的多層墻體成像衰減補償算法,有效補償了單視角探測下建筑布局圖像強度的差異性;4.針對不同視角下的多幅建筑布局圖像,提出門限平均加權(quán)融合、自適應加權(quán)融合、像素選大融合和小波變換融合等圖像融合方法,形成一幅更清晰、信噪比更高的全景圖像;5.提出一種基于子孔徑成像的多徑幻象抑制方法,在單視角探測條件下利用目標多徑的“方向依賴”特性有效抑制了多徑幻象目標,提升了隱蔽目標圖像信噪比;6.在多視角探測條件下,針對隱蔽目標多徑幻象干擾問題,分析幻象成因機理,將不同視角下的圖像作相乘融合,大大抑制了多徑幻象,提升了隱蔽目標圖像信噪比。
文內(nèi)圖片：
圖片說明：左圖為原始回波數(shù)據(jù)，，右圖為距離像平面
[Abstract]:Through the need of stability, investigation and rescue, through-wall radar technology has become the focus of research. The building perspective detection scene imaging technology is based on the through-wall radar imaging technology, which mainly realizes the two functions of the building layout imaging and the concealed target imaging, and is used for forming the building layout panoramic image and the hidden target image respectively. The detection mode of the through-wall radar synthetic aperture imaging technology can be divided into the strip SAR mode and the spotlight SAR mode. The traditional stripe SAR mode is multi-angle detection, but the environment complexity of the practical application is usually not the condition of multi-view detection. In addition, the signal intensity attenuation caused by the through-wall propagation of the electromagnetic signal brings about the non-uniformity of the imaging intensity of the building layout, which brings great difficulty to the detection and the acquisition of the final building layout. Furthermore, in the closed detection environment of the building, the target multipath echo interference caused by the wall body is serious, a large number of multi-path phantom is generated in the imaging process, and the high-quality hidden target image cannot be formed. In view of the above problems, the following work is done:1. For the vehicle-mounted spotlight SAR mode, the scene imaging can be done at one time in a single visual angle, which is suitable for the detection in a complex environment. The signal model of the vehicle-mounted spotlight SAR mode is studied, and the RMA and BP imaging algorithm in this mode are given. 2. A method of PCA image enhancement based on fuzzy logic is proposed, which can effectively restrain the clutter and noise and enhance the image strength of the building layout. A multi-layer wall imaging attenuation compensation algorithm based on the Hough transform threshold detection is proposed, which can effectively compensate the difference of the image intensity of the building layout under the single-view angle detection. Aiming at the images of multiple buildings in different visual angles, an image fusion method such as a threshold average weight fusion, a self-adaptive weighted fusion, a pixel selection fusion and a wavelet transform fusion is proposed to form a panoramic image with a clearer and higher signal-to-noise ratio; and 5. A multi-path phantom suppression method based on sub-aperture imaging is proposed, and the multi-path phantom object is effectively suppressed by the "direction dependence" characteristics of the target multipath under the single-view angle detection condition, and the signal-to-noise ratio of the hidden target image is improved; Under the condition of multi-view detection, aiming at the problem of multi-path phantom interference of the hidden target, the mechanism of the formation of the phantom is analyzed, the images under different views are combined and fused, the multi-path phantom is greatly reduced, and the signal-to-noise ratio of the hidden target image is improved.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN957.52


本文編號：2511702