图像分块（任意大小的）

%实验目的： 学习JPEG压缩编码 %实验内容： %一．实现基本JPEG的压缩和编码分三个步骤： %1.首先通过DCT变换去除数据冗余； %2.使用量化表对DCT系数进行量化； %3．对量化后的系数进行Huffman编码。 %具体源程序由主程序及两个子程序（DCT量化、Huffman编码）组成： %1．主程序 I=imread('1.jpg'); yiq=rgb2ntsc(I); my=[16 11 10 16 24 40 51 61;12 12 14 19 26 58 60 55; 14 13 16 24 40 57 69 56;14 17 22 29 51 87 80 62; 18 22 37 56 68 109 103 77;24 35 55 64 81 104 113 92; 49 64 78 87 103 121 120 101;72 92 95 98 112 100 103 99]; miq=[17 18 24 47 99 99 99 99;18 21 26 66 99 99 99 99; 24 26 56 99 99 99 99 99;47 66 99 99 99 99 99 99; 99 99 99 99 99 99 99 99;99 99 99 99 99 99 99 99; 99 99 99 99 99 99 99 99;99 99 99 99 99 99 99 99]; I1=yiq(:,:,1); I2=yiq(:,:,2); [m n]=size(I1); t1=8;ti1=1; while(t1<m) t1=t1+8;ti1=ti1+1; end t2=8;ti2=1; while(t2<n) t2=t2+8;ti2=ti2+1; end times=0; for k=0:ti1-2 for j=0:ti2-2 dct8x8(I1(k*8+1:k*8+8,j*8+1:j*8+8),my,times*64+1); dct8x8(I2(k*8+1:k*8+8,j*8+1:j*8+8),miq,times*64+1); times=times+1; end block(I2(k*8+1:k*8+8,j*8+1:t2),[8 8], 'dctmtx(8)'); end for j=0:ti2-2 dct8x8(I1(k*8+1:t1,j*8+1:j*8+8),times*64+1); times=times+1; end dct8x8(I1(k*8+1:t1,j*8+1:t2),times*64+1); %2．function 定义DCT量化子程序 dct8x8(I,m,s) T=inline('dctmtx(8)'); y=blkproc(I,[8 8],T); y=round(y./m); p=1;te=1; while(p<=64) for q=1:te y1(s+p)=y(te-q+1,q);p=p+1; end for q=te:-1:1 y1(s+p)=y(te-q+1,q);p=p+1; end end f=haffman(y1); c(s:s+64,1)=f(:,1);c(s:s+64,2)=f(:,2);c(s:s+64,3)=f(:,3) %3．function 定义Huffman编码子程序 c=haffman(I) [m,n]=size(I); p1=1;s=m*n; for k=1:m for h=1:n f=0; for b=1:p1-1 if(c(b,1)==I(k,h)) f=1;break;end end if(f==0) c(p1,1)=I(k,h);p1=p1+1;end end end for g=1:p1-1 p(g)=0;c(g,2)=0; for k=1:m for h=1:n if(c(g,1)==I(k,h)) p(g)=p(g)+1;end end end p(g)=p(g)/s; end pn=0;po=1; while(1) if(pn>=1.0) break; else [pm p2]=min(p(1:p1-1));p(p2)=1.1; [pm2,p3]=min(p(1:p1-1));p(p3)=1.1; pn=pm+pm2;p(p1)=pn; tree(po,1)=p2;tree(po,2)=p3; po=po+1;p1=p1+1; end end for k=1:po-1 tt=k;m1=1; if(or(tree(k,1)<9,tree(k,2)<9)) if(tree(k,1)<9) c(tree(k,1),2)=c(tree(k,1),2)+m1; m2=1; while(tt<po-1) m1=m1*2; for h=tt:po-1 if(tree(h,1)==tt+g) c(tree(k,1),2)=c(tree(k,1),2)+m1; m2=m2+1;tt=h;break; elseif(tree(h,2)==tt+g) m2=m2+1;tt=h;break; end end end c(tree(k,1),3)=m2; end tt=k;m1=1; if(tree(k,2)<9) m2=1; while(tt<po-1) m1=m1*2; for h=tt:po-1 if(tree(h,1)==tt+g) c(tree(k,2),2)=c(tree(k,2),2)+m1; m2=m2+1;tt=h;break; elseif(tree(l,2)==tt+g) m2=m2+1,tt=h;break; end end end c(tree(k,2),3)=m2; end end end