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1、clearX=imread('lena512.bmp');data=uint8(X);[zipped,info]=huffencode(data);%調(diào)用Huffman編碼程序進(jìn)行壓縮unzipped=huffdecode(zipped,info,data);%調(diào)用Huffman編碼程序進(jìn)行解碼%顯示原始圖像和經(jīng)編碼后的圖像，顯示壓縮比，并計(jì)算均方根誤差得erms=0，表示是Huffman是無失真編碼subplot(121);imshow(data);subplot(122);imshow(unzipped);%erms=compare(data(:),unzipped(:))cr=in
2、fo.ratiowhosdataunzippedzippedfunction[zipped,info]=huffencode(vector)%輸入和輸出都是uint8格式%info返回解碼需要的結(jié)構(gòu)信息%info.pad是添加的比特?cái)?shù)%info.huffcodes是Huffman碼字%info.rows是原始圖像行數(shù)%info.cols是原始圖像列數(shù)%info.length是原始圖像數(shù)據(jù)長度%info.maxcodelen是最大碼長if~isa(vector,'uint8')error('inputargumentmustbeauint8vector');end[m,n]=size(ve
3、ctor);vector=vector(:)';f=frequency(vector);%計(jì)算各符號出現(xiàn)的概率symbols=find(f~=0);f=f(symbols);[f,sortindex]=sort(f);%將符號按照出現(xiàn)的概率大小排列symbols=symbols(sortindex);len=length(symbols);symbols_index=num2cell(1:len);codeword_tmp=cell(len,1);%生成Huffman樹，得到碼字編碼表whilelength(f)>1index1=symbols_index{1};index2=symbo
4、ls_index{2};codeword_tmp(index1)=addnode(codeword_tmp(index1),uint8(0));codeword_tmp(index2)=addnode(codeword_tmp(index2),uint8(1));f=[sum(f(1:2)),f(3:end)];symbols_index=[{[index1,index2]},symbols_index(3:end)];[f,sortindex]=sort(f);symbols_index=symbols_index(sortindex);endcodeword=cell(256,1);
5、codeword(symbols)=codeword_tmp;len=0;forindex=1:length(vector)%得到整個(gè)圖像所有比特?cái)?shù)len=len+length(codeword{double(vector(index))+1});endstring=repmat(uint8(0),1,len);pointer=1;forindex=1:length(vector)%對輸入圖像進(jìn)行編碼code=codeword{double(vector(index))+1};len=length(code);string(pointer+(0:len-1))=code;pointer=
6、pointer+len;endlen=length(string);pad=8-mod(len,8);ifpad>0string=[stringuint8(zeros(1,pad))];endcodeword=codeword(symbols);codelen=zeros(size(codeword));weights=2.^(0:23);maxcodelen=0;forindex=1:length(codeword)len=length(codeword{index});iflen>maxcodelen;maxcodelen=len;endiflen>0code=sum(weights
7、(codeword{index}==1));code=bitset(code,len+1);codeword{index}=code;codelen(index)=len;endendcodeword=[codeword{:}];%計(jì)算壓縮的向量cols=length(string)/8;string=reshape(string,8,cols);weights=2.^(0:7);zipped=uint8(weights*doubl
