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題 名 | 水下超音波影像品質之改善--探頭空間頻率響應之求取與逆摺積法之應用 |
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作 者 | 鄭勝文; 趙岷江; | 書刊名 | 中華民國音響學刊 |
卷 期 | 3:1 1995.05[民84.05] |
頁 次 | 頁46-58 |
分類號 | 448.5 |
關鍵詞 | 空間響應; 超音波音場量側值; 逆摺積法; 數位訊號處理; |
語 文 | 中文(Chinese) |
中文摘要 | 本文探討探頭空間響應對超音波音場量測值之影響,提出探頭空間響應之求取方 法,並運用逆摺積法數位訊號處理技巧去除此探頭效應,以改善水下合成孔徑超音波影像 之品質。本文針對圓形平面超音波探頭,建立空間響應之數學模型,並以實驗獲取探頭空 間頻率響應進行驗證。在消除探頭效應之逆摺積數位訊號處理部分,採擬逆濾波函數 (pseudoinverse filter)法,降低探頭空間響應所引致之解析度劣化,改善影像品質。結 果顯示,當探頭尺寸增大時,合成孔徑超音波影像之有效空間頻寬隨之減小,解析度因而 劣化。而經探頭空間響應逆摺積處理後,可獲得有效改善。 |
英文摘要 | This paper studies the effect of transducer spatial response on the measured underwater ultrasonic pressure field, and eliminates this effect by using of the deconvolution technique to improve the image qudlity of underwater Synthetic Aperture Utrasonic Holography (SAUH) imaging system. Plane circular non-focused ultrasonic transducers are adopted in this paper. First, a mathematical model to calculate the transducer spatial response is proposed, along with experiments to verify it. To eliminate the effect of transducer spatial response on SAUH images, we use of the pseudo-innerse filter and apply the deconvolution technique. Both numberical analysis and SAUH experiment are conducted, and results show, the spatial frequency response of transducer is a crucial factor affecting the image resolution of a SAUH imaging system, and larger diameter transducers make image resolution worse. However, by deconvolving the spatial effect of transducer, the image resolution is apparently improved. |
本系統中英文摘要資訊取自各篇刊載內容。