getNaturalStat_multiscale

 getNaturalStat_multiscale - Obtain natural statistics for multiscale Gabor responses

0001 function getNaturalStat_multiscale
0002 % getNaturalStat_multiscale - Obtain natural statistics for multiscale Gabor responses
0003 
0004 load ../template_params.mat
0005 negImageNames = dir('../image/neg/*.jpg');
0006 negImageNames = negImageNames(1:min(5,end));
0007 numImage = length(negImageNames);
0008 mkdir('../result');
0009 
0010 for s = 1 : nGaborScale
0011     scaleFilter = GaborScale(s);
0012     %% compute histogram of q()
0013     numBin = floor(GaborSaturation/binSize)+1;  % binnumbers
0014     histog = zeros(numBin, 1, 'single');  % store F
0015     r = (0:(numBin-1))*binSize;
0016     halfFilterSize = ( size(GaborFilter{nGaborOri*(s-1)+1},1)-1 ) / 2;
0017     disp(['start histogramming negative images at Gabor length ' num2str(2*halfFilterSize+1)]);
0018     
0019     allFilteredImage = cell(length(negImageNames), nGaborOri);
0020     sizex = zeros(numImage,1,'int32');
0021     sizey = zeros(numImage,1,'int32');
0022     for i = 1:numImage
0023         load(sprintf('../feature/neg/%s.mat',negImageNames(i).name),'S1Map');
0024         allFilteredImage(i,:) = S1Map(nGaborOri*(s-1)+(1:nGaborOri));
0025         sizex(i) = size(allFilteredImage{i,1},1);
0026         sizey(i) = size(allFilteredImage{i,1},2);
0027     end
0028 
0029     Chistogram(numImage, nGaborOri, allFilteredImage, halfFilterSize, sizex, sizey, binSize, numBin, histog, GaborSaturation);
0030     %% compute stored lambda, expectation, logZ
0031 
0032     storedExpectation = zeros(numStoredPoint, 1); 
0033     Z = zeros(numStoredPoint, 1); 
0034     for k=1:numStoredPoint
0035        lambda = (k-1.)*spacing; 
0036        p = exp(lambda*r).*(histog'); 
0037        Z(k) = sum(p*binSize); p = p/Z(k); 
0038        storedExpectation(k) = sum(r.*p*binSize);
0039     end
0040     storedLambda = (0:(numStoredPoint-1))*spacing; 
0041     storedLogZ = log(Z);
0042 
0043     %% store filter properties and exponential model
0044     storeName = ['../result/naturalStat' num2str(s-1) '.mat'];
0045     if SinglePrecision > 0
0046         storedLambda = single(storedLambda);
0047         storedExpectation = single(storedExpectation);
0048         storedLogZ = single(storedLogZ);
0049         r = single(r);
0050         histog = single(histog);
0051     end
0052     save(storeName, 'storedLambda', 'storedExpectation', 'storedLogZ', 'numBin', 'r', 'histog'); 
0053 end
0054 
0055 %% display the comparison
0056 rMat = zeros(nGaborScale,length(r));
0057 histogMat = zeros(nGaborScale,length(r));
0058 for s = [1 4 7]
0059     load(sprintf('../result/naturalStat%d.mat',s-1),'r','histog');
0060     rMat(s,:) = r(:);
0061     histogMat(s,:) = histog(:);
0062 end
0063 
0064 figure; plot(rMat([1 4 7],:)',histogMat([1 4 7],:)');
0065 legend({'1','4','7'});
0066 title('comparison of background density'); xlabel('sigmoid(response)'); ylabel('density');
0067 set(gca,'FontSize',16); % adjust the display format and save the plot
0068 set(get(gca,'XLabel'),'FontSize',18);
0069 set(get(gca,'YLabel'),'FontSize',18);
0070 set(get(gca,'Title'),'FontSize',18);
0071 set(gcf, 'PaperPositionMode', 'auto');
0072 print('-dpng','../result/background_density_comparison_over_scale.png');
0073 saveas(gcf, '../result/background_density_comparison_over_scale.eps', 'epsc');
0074 
0075 lambdaMat = zeros(nGaborScale,length(storedLambda));
0076 expMat = zeros(nGaborScale,length(storedLambda));
0077 for s = [1 4 7]
0078     load(sprintf('../result/naturalStat%d.mat',s-1),'storedLambda','storedExpectation');
0079     lambdaMat(s,:) = storedLambda(:);
0080     expMat(s,:) = storedExpectation(:);
0081 end
0082 
0083 figure; plot(lambdaMat([1 4 7],:)',expMat([1 4 7],:)');
0084 title('comparison of lambda-expectation relation'); xlabel('lambda'); ylabel('expected value');
0085 legend({'1','4','7'},'Location','South');
0086 set(gca,'FontSize',16); % adjust the display format and save the plot
0087 set(get(gca,'XLabel'),'FontSize',18);
0088 set(get(gca,'YLabel'),'FontSize',18);
0089 set(get(gca,'Title'),'FontSize',18);
0090 set(gcf, 'PaperPositionMode', 'auto');
0091 print('-dpng','../result/lambda_exp_comparison_over_scale.png');
0092 saveas(gcf, '../result/lambda_exp_comparison_over_scale.eps', 'epsc');