Created
February 20, 2013 09:14
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图像质量监测的matlib实现。
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| %说明：本文件为计算两幅视频图象相对于高清晰图象的质量，其中： | |
| %eyechart1.bmp为未处理前质量较差图象，核心区域的截图保存为area_eyechart1.bmp | |
| %eyechart2.bmp为某种算法处理后质量较好图象，核心区域的截图保存为area_eyechart2.bmp | |
| %eyechart3.bmp为高清晰参考图象，核心区域的截图保存为area_eyechart3.bmp | |
| %程序流程为 | |
| %第一步：先分别从eyechart1.bmp、eyechart2.bmp、eyechart3.bmp中截取出核心区域，并分别保存为area_eyechart1.bmp、area_eyechart1.bmp、area_eyechart3.bmp | |
| %第二步：以area_eyechart3.bmp为参考图象，计算area_eyechart1.bmp的PSNR、模糊系数KBlur、质量指数Q | |
| %第三步：以area_eyechart3.bmp为参考图象，计算area_eyechart2.bmp的PSNR、模糊系数KBlur、质量指数Q | |
| %程序可直接运行，运行结果为： | |
| %1.保存并显示生成的截图文件area_eyechart1.bmp、area_eyechart1.bmp、area_eyechart3.bmp | |
| %2、在控制台先显示第二步的计算结果，即area_eyechart1.bmp的三个质量指标，然后接着显示第三步的计算结果，即area_eyechart2.bmp的三个质量指标 | |
| %运行结果分析：area_eyechart2.bmp的PSNR和质量指数Q高，表明其质量较好，而area_eyechart1.bmp的模糊系数KBlur较大 | |
| %这是因为其有很多噪声被当着了边缘能量来计算，这也从一个方面说明模糊系数KBlur的应用具有局限性,但前者KBlur>1，后者<1，理论上只有模糊的情况下 | |
| %KBlur是<=1的，这也可根据KBlur与1的关系来判定图象收噪声污染的程度. | |
| %******************从eyechart1.bmp,eyechart2.bmp两个文件中截取测试图象区域,可保证两图象截取的区域严格对准***** | |
| a=imread('eyechart1.bmp','bmp'); | |
| b=a([203:396],[249:440]); | |
| a=imread('eyechart2.bmp','bmp'); | |
| c=a([203:396],[249:440]); | |
| %*******************从eyechart3.bmp中截取测试参考图象，截取部分需要进行缩放，使之与eyechart1.bmp,eyechart2.bmp截取部分大小匹配******************************************************************* | |
| a=imread('eyechart3.bmp','bmp'); | |
| d=a([62:406],[60:395]); | |
| e=imresize(d,[length(b(:,1)),length(b(1,:))], 'bicubic');%由于eyechart3.bmp和eyechart1.bmp,eyechart2.bmp比例不一样，这里要进行比例调整 | |
| imwrite(b,'area_eyechart1.bmp','bmp'); | |
| imwrite(c,'area_eyechart2.bmp','bmp'); | |
| imwrite(e,'area_eyechart3.bmp','bmp'); | |
| subplot(1,3,1); | |
| imshow(e); | |
| title('eyechart3.bmp截取部分，参考图象'); | |
| hold on; | |
| subplot(1,3,2); | |
| imshow(b); | |
| title('eyechart1.bmp截取部分'); | |
| hold on; | |
| subplot(1,3,3); | |
| imshow(c); | |
| title('eyechart2.bmp截取部分'); | |
| %*******************以下部分为计算截取图象area_eyechart1.bmp和area_eyechart1.bmp的PSNR、模糊系数、质量指数Q* | |
| % 本文件功能为对计算污染图象相对于源图象的质量 | |
| clc; | |
| clear; | |
| PSNRenable=1;%PSNR计算使能，为0不计算，为1，计算 | |
| KBlurenable=1;%模糊系数KBlur计算使能，为0不计算，为1，计算 | |
| Qenable=1;%质量指数Q计算使能，为0不计算，为1，计算 | |
| for m=1:2 | |
| imsrcnamehead='area_eyechart3';%源图象文件名头 | |
| imsrcnameext='bmp';%源图象文件名扩展 | |
| if m==1 %以area_eyechart1.bmp为测试图象 | |
| imdstname=strcat('area_eyechart1','.',imsrcnameext);%污染图象文件名，可修改 | |
| elseif m==2%以area_eyechart2.bmp为测试图象 | |
| imdstname=strcat('area_eyechart2','.',imsrcnameext);%污染图象文件名，可修改 | |
| end | |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| iminfo=imfinfo(strcat(imsrcnamehead,'.',imsrcnameext));%源图象信息读取 | |
| imsrc=imread(strcat(imsrcnamehead,'.',imsrcnameext));%源图象读取 | |
| imdst=imread(imdstname,imsrcnameext);%污染图象读取 | |
| doubledoubleimsrc=double(imsrc);%转换为浮点类型 | |
| doubledoubleimdst=double(imdst);%转换为浮点类型 | |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%源图象和污染图象读取 | |
| W=iminfo.Width;%图象度 | |
| H=iminfo.Height;%图象高 | |
| %///////////////////PSNR计算///////////////////////////////// | |
| if PSNRenable==1 | |
| PSNR=0.0;%PSNR赋初值 | |
| for j=1:H | |
| for i=1:W | |
| PSNRPSNR=PSNR+double((doubleimsrc(j,i)-doubleimdst(j,i))*(doubleimsrc(j,i)-doubleimdst(j,i))); | |
| end | |
| end | |
| PSNRPSNR=PSNR/W/H; | |
| PSNR=10*log10(255*255/PSNR) | |
| %////////////////////PSNR计算完毕////////////////////////////////// | |
| end | |
| %///////////////////模糊系数KBlur计算///////////////////////////////// | |
| if KBlurenable==1 | |
| Sin=0.0;%Sin赋初值 | |
| Sout=0.0; | |
| for j=2:H-1 | |
| for i=2:W-1 | |
| t=doubleimsrc(j-1,i+1)+doubleimsrc(j+1,i-1)-doubleimsrc(j-1,i-1)-doubleimsrc(j+1,i+1); | |
| if t<0 t=-t; | |
| end | |
| SinSin=Sin+t;%源图象邻域边缘能量计算 | |
| t=doubleimdst(j-1,i+1)+doubleimdst(j+1,i-1)-doubleimdst(j-1,i-1)-doubleimdst(j+1,i+1); | |
| if t<0 t=-t; | |
| end | |
| SoutSout=Sout+t;%污染图象邻域边缘能量计算 | |
| end | |
| end | |
| KBlur=Sout/Sin | |
| end | |
| %////////////////////KBlur计算完毕//////////////////////////////////////// | |
| %///////////////////质量指数Q计算////////////////////////////////////////// | |
| if Qenable==1 | |
| Q=0.0;%Q赋初值 | |
| Qnum=0;%图象以7X7块大小计算每块的Q，逐象素的移动块窗口，这里Qnum为块数量的计数 | |
| for j=4:H-3 | |
| for i=4:W-3 | |
| midsrc=0.0; | |
| middst=0.0; | |
| varsrc=0.0; | |
| vardst=0.0;%源图象和污染图象块内的平均值和方差赋初值 | |
| varsrcdst=0.0;%源图象和污染图象块内的协方差赋初值 | |
| for n=-3:3 | |
| for m=-3:3 | |
| midsrcmidsrc=midsrc+doubleimsrc(j+n,i+m); | |
| middstmiddst=middst+doubleimdst(j+n,i+m); | |
| end | |
| end | |
| midsrcmidsrc=midsrc/49; | |
| middstmiddst=middst/49; | |
| %源图象和污染图象块内的平均值计算 | |
| for n=-3:3 | |
| for m=-3:3 | |
| varsrcvarsrc=varsrc+(doubleimsrc(j+n,i+m)-midsrc)*(doubleimsrc(j+n,i+m)-midsrc); | |
| vardstvardst=vardst+(doubleimdst(j+n,i+m)-middst)*(doubleimdst(j+n,i+m)-middst); | |
| varsrcdstvarsrcdst=varsrcdst+(doubleimsrc(j+n,i+m)-midsrc)*(doubleimdst(j+n,i+m)-middst); | |
| end | |
| end | |
| varsrcvarsrc=varsrc/48; | |
| vardstvardst=vardst/48; | |
| varsrcdstvarsrcdst=varsrcdst/48; | |
| if ((varsrc+vardst)*(midsrc*midsrc+middst*middst))~=0 %分母不为零的块才计算质量指数Q | |
| QQ=Q+4*varsrcdst*midsrc*middst/((varsrc+vardst)*(midsrc*midsrc+middst*middst)); | |
| %源图象和污染图象块内Q计算完毕 | |
| QnumQnum=Qnum+1;%块计数加1 | |
| end | |
| end | |
| end | |
| QQ=Q/Qnum | |
| end | |
| %////////////////////质量指数Q计算完毕///////////////////////////////////// | |
| end | |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%图象质量计算完毕 |
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