采用方位向自適應(yīng)濾波器提高SAR自聚焦的性能
To improve the performance of autofocus in SAR images with an azimuth adaptive filter
-
摘要: 機載合成孔徑雷達的方位向降采樣經(jīng)常會降低原始圖像的信噪比。自動聚焦是從雷達回波信號中提取多普勒參數(shù)，以獲得高分辨率SAR圖像。該文分析了信噪比對自聚焦的影響，提出利用自適應(yīng)濾波器來做方位向預(yù)濾波和降采樣，在降低采樣率的同時，保持原始圖像的信噪比，再經(jīng)有效的自動聚焦算法，得到較準確的多普勒參數(shù)估計值，從而獲取高分辨率SAR圖像。通過對實際SAR回波數(shù)據(jù)的處理，證明了采用自適應(yīng)濾波器后，圖像信噪比能比采用普通濾波器時有較大提高，從而顯著改善自動聚焦的收斂性，提高成像質(zhì)量。
-
關(guān)鍵詞:
- 自適應(yīng)濾波器; 信噪比; 自動聚焦
Abstract: In SAR azimuth signal processing, it is very common to subsample the raw data with a filter, which may reduce the Signal Noise Ratio(SNR) of the raw image. Since autofocus is to estimate the Doppler parameters from the raw data, with the reduced SNR, the result of autofocus may be incorrect. And images processed with the incorrect parameters will be worsened. This paper analyses the effect of SNR on autofocus and proposes an adaptive filter in SAR azimuth subsampling to keep SNR as high as possible, so that the performance of autofocus can be improved and higher image quality achieved. Finally, an image processed with the adaptive filter is contrasted with the result of a traditional filter, which proves the effectiveness of the adaptive filter on autofocus and the final image. -
J.C. Curlander.[J].R. N. McDonough, Synthetic Aperture Radar-Systems and Signal Processing,New York, John Wiley Sons.1991,:-[2]張澄波,綜合孔徑雷達原理、系統(tǒng)分析與應(yīng)用,北京,科學(xué)出版社,1989,118-124.[3]吳兆熊,黃振興,黃順吉,數(shù)字信號處理(下冊),北京,國防工業(yè)出版社,1988,1-20.[4]陸大 ,隨機過程及其應(yīng)用;北京,清華大學(xué)出版社,1986,242-245,474-491.[5]程佩青,數(shù)字信號處理教程,北京,清華大學(xué)出版社,1995,185-212. -
計量
- 文章訪問數(shù): 1995
- HTML全文瀏覽量: 88
- PDF下載量: 487
- 被引次數(shù): 0
下載:
