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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/18395

Title: 多輸入輸出系統下之固定區塊大小小波影像傳輸
Fixed Blocksize Wavelet Image Transmission Over MIMO System
Authors: Hung-Yen Wei
魏宏諺
Contributors: NTOU:Department of Communications Navigation and Control Engineering
國立臺灣海洋大學:通訊與導航工程系
Keywords: 小波轉換;向量量化;位元分配;時空區塊碼
Wavelet Transform;STBC;Bit Allocation;Vector Quantization
Date: 2009
Issue Date: 2011-07-04
Abstract: 小波轉換(wavelet transform)可提供具有對影像多重解析(multiresolution)的功用,因此被廣泛地使用在影像壓縮技術上。而為了增加影像的壓縮比率,一般將小波轉換後的小波係數經由向量量化(vector quantization)來進行壓縮,而使用向量量化的主要原因是由於它具有很高的壓縮比率,而且在解壓縮時也相當容易。但在實用上,影像壓縮法除了壓縮比率外,編碼速度也是考量的重點。 在做小波轉換之前,我們先將整張影像分割成不同尺寸區塊,如16*16、32*32、64*64以及128*128等不同尺寸區塊。然後經小波轉換後,再將每一個子頻帶區塊的小波係數能量值(variance),做為位元分配的依據。而依照分配到的位元選擇最適當的編碼簿(codebook),並由編碼後所得到的失真值來調整位元率。 接著將影像之小波壓縮與時空區塊碼互相結合,分別將不同尺寸區塊大小之小波壓縮在不同的天線組合下傳輸,找出哪種組合方式下傳輸效能最佳。
Wavelet transform has been received a great interest because it provides a multiresolution representation of images. Wavelet transform is now a widely used technique in image compression. By way of vector quantization technique, the wavelet transform coefficients can be compressed further. For real time image compression, achieving high data compression ratio and coding efficiency at the same time are both important.   The image frame is devided into many subblocks with block sizes ;16*16、32*32、64*64 and 128*128 before using wavelet transform.After the wavelet transform, select appropriate size for codebook, bit allocation assignment is applied associated with the variance of each subband image block. We have also adopted rate-distortion concept to adjust the compressed bit rate. The processed image subblocks are combined with Space Time Block Code(STBC) before transmitted. Use the different way to compress the different sizes of wavelet in antenna combination to transform. Find out witch combination is the best efficacy of transformation.
URI: http://ethesys.lib.ntou.edu.tw/cdrfb3/record/#G0M95670045
http://ntour.ntou.edu.tw/ir/handle/987654321/18395
Appears in Collections:[通訊與導航工程學系] 博碩士論文

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