旁瓣峰值 的英文怎麼說
中文拼音 [bàngbànfēngzhí]
旁瓣峰值
英文
side lobe peak-
In the terms of interpolation, the image reconstructed from nearest interpolation or linear interpolation has good edge but serious noise ; reconstruction from 4 * 4cubic interpolation or three b - spline or three - order lagrange interpolations has better local character. 2 x 2cubic interpolations which has both better edge and local character is the ideal interpolation, the following is the basic principle during reconstruction : ( 1 ) the more width of interpolation, the more number of summation and the more order of interpolation polynomial, the higher of density resolution ; ( 2 ) the more of interpolation polynomial and width of interpolation, the more of reconstruction time simultaneously, aimed at eliminating the effects of noise contained in projection data, in this paper, author analysis cause and effects of common artifacts. importantly, discusses convolution back - projection reconstruction algorithm with a shift axis of rotation has been derived for correcting images that acquired with a divergence axis of rotation using the fan beam geometry with an angle - equaled detector
在ct圖像重建時，選擇有限帶寬窗有較好的空間解析度，三角形窗有較好的密度解析度，選擇餘弦窗則使得空間解析度與密度解析度的折衷；從窗函數的頻譜角度來講，可以用於圖像重建的一個良好的卷積窗函數應該具備以下條件： （ ? ）小的3db帶寬b ，即最小的主瓣寬度； （ ? ）最小的旁瓣最大峰值a ； （ ? ）最大的旁瓣峰值衰減速度d ；就內插函數而言，臨近點內插與線性內插重建圖像噪聲大，但有較好的邊緣與細節； 4 4三次內插、三次b -樣條與四次拉格朗日多項式內插圖像平滑，局部特性較好。Thirdly, a modified extended chirp scaling ( ecs ) algorithm is presented, which solves the problem of producding fine focused images in the class of chirp scaling ( cs ) algorithm. lt can be used for uwb - sar imaging effectively. the phas e error produced by cs operation are analyzed. a windowed process in two dimension frequency domain before cs operation are proposed. it can improve the quality of image and widen the effectively swath and increase the peak to sidelobe ratio ( pslr )
然後針對chirpscaling （ cs ）類演算法不能對參考點精確聚焦的問題，提出了一種改進的擴展cs （ ecs ）演算法，實現了對uwb - sar的高效成像；分析了cs操作產生的相位誤差，提出在cs操作之前在二維頻率域對信號加窗，除有效提高信號的峰值旁瓣比（ pslr ）外，還可以提高圖像質量，增加有效測繪帶寬度。
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