matlab版hog+svm图像二分类

function F = hogcalculator(img, cellpw, cellph, nblockw, nblockh,... nthet, overlap, isglobalinterpolate, issigned, normmethod) % HOGCALCULATOR calculate R-HOG feature vector of an input image using the % procedure presented in Dalal and Triggs's paper in CVPR 2005. % % Author: timeHandle % Time: March 24, 2010 % May 12ㄛ2010 update. % % this copy of code is written for my personal interest, which is an % original and inornate realization of [Dalal CVPR2005]'s algorithm % without any optimization. I just want to check whether I understand % the algorithm really or not, and also do some practices for knowing % matlab programming more well because I could be called as 'novice'. % OpenCV 2.0 has realized Dalal's HOG algorithm which runs faster % than mine without any doubt, 禿(究�系)秀 . Ronan pointed a error in % the codeㄛthanks for his correction. Note that at the end of this % code, there are some demonstration codeㄛplease remove in your work. % % F = hogcalculator(img, cellpw, cellph, nblockw, nblockh, % nthet, overlap, isglobalinterpolate, issigned, normmethod) % % IMG: % IMG is the input image. % % CELLPW, CELLPH: % CELLPW and CELLPH are cell's pixel width and height respectively. % % NBLOCKW, NBLCOKH: % NBLOCKW and NBLCOKH are block size counted by cells number in x and % y directions respectively. % % NTHET, ISSIGNED: % NTHET is the number of the bins of the histogram of oriented % gradient. The histogram of oriented gradient ranges from 0 to pi in % 'unsigned' condition while to 2*pi in 'signed' condition, which can % be specified through setting the value of the variable ISSIGNED by % the string 'unsigned' or 'signed'. % % OVERLAP: % OVERLAP is the overlap proportion of two neighboring block. % % ISGLOBALINTERPOLATE: % ISGLOBALINTERPOLATE specifies whether the trilinear interpolation % is done in a single global 3d histogram of the whole detecting % window by the string 'globalinterpolate' or in each local 3d % histogram corresponding to respective blocks by the string % 'localinterpolate' which is in strict accordance with the procedure % proposed in Dalal's paper. Interpolating in the whole detecting % window requires the block's sliding step to be an integral multiple % of cell's width and height because the histogram is fixing before % interpolate. In fact here the so called 'global interpolation' is % a notation given by myself. at first the spatial interpolation is % done without any relevant to block's slide position, but when I was % doing calculation while OVERLAP is 0.75, something occurred and % confused me o__O"＃ . This let me find that the operation I firstly % did is different from which mentioned in Dalal's paper. But this % does not mean it is incorrect ^♁^, so I reserve this. As for name, % besides 'global interpolate', any others would be all ok, like 'Lady GaGa' % or what else, :-). % % NORMMETHODㄩ % NORMMETHOD is the block histogram normalized method which can be % set as one of the following strings: % 'none', which means non-normalization; % 'l1', which means L1-norm normalization; % 'l2', which means L2-norm normalization; % 'l1sqrt', which means L1-sqrt-norm normalization; % 'l2hys', which means L2-hys-norm normalization. % Fㄩ % F is a row vector storing the final histogram of all of the blocks % one by one in a top-left to bottom-right image scan manner, the % cells histogram are stored in the same manner in each block's % section of F. % % Note that CELLPW*NBLOCKW and CELLPH*NBLOCKH should be equal to IMG's % width and height respectively. % % Here is a demonstration, which all of parameters are set as the % best value mentioned in Dalal's paper when the window detected is 128*64 % size(128 rows, 64 columns): % F = hogcalculator(window, 8, 8, 2, 2, 9, 0.5, % 'localinterpolate', 'unsigned', 'l2hys'); % Also the function can be called like: % F = hogcalculator(window); % the other parameters are all set by using the above-mentioned "dalal's % best value" as default. % if nargin < 2 % set default parameters value. cellpw = 8; cellph = 8; nblockw = 2; nblockh = 2; nthet = 9; overlap = 0.5; isglobalinterpolate = 'localinterpolate'; issigned = 'unsigned'; normmethod = 'l2hys'; else if nargin < 10 error('Input parameters are not enough.'); end end % check parameters's validity. [M, N, K] = size(img); if mod(M,cellph*nblockh) ~= 0 error('IMG''s height should be an integral multiple of CELLPH*NBLOCKH.'); end if mod(N,cellpw*nblockw) ~= 0 error('IMG''s width should be an integral multiple of CELLPW*NBLOCKW.'); end if mod((1-overlap)*cellpw*nblockw, cellpw) ~= 0 ||... mod((1-overlap)*cellph*nblockh, cellph) ~= 0 str1 = 'Incorrect OVERLAP or ISGLOBALINTERPOLATE parameter'; str2 = ', slide step should be an intergral multiple of cell size'; error([str1, str2]); end % set the standard deviation of gaussian spatial weight window. delta = cellpw*nblockw * 0.5; % calculate gradient scale matrix. hx = [-1,0,1]; hy = -hx'; gradscalx = imfilter(double(img),hx); gradscaly = imfilter(double(img),hy); % if K > 1 maxgrad = sqrt(double(gradscalx.*gradscalx + gradscaly.*gradscaly)); [gradscal, gidx] = max(maxgrad,[],3); gxtemp = zeros(M,N); gytemp = gxtemp; for kn = 1:K ttempx = gradscalx(:,:,kn); ttempy = gradscaly(:,:,kn); tmpindex = find(gidx==kn); gxtemp(tmpindex) = ttempx(tmpindex); gytemp(tmpindex) =ttempy(tmpindex); end gradscalx = gxtemp; gradscaly = gytemp; else gradscal = sqrt(double(gradscalx.*gradscalx + gradscaly.*gradscaly)); end % calculate gradient orientation matrix. % plus small number for avoiding dividing zero. gradscalxplus = gradscalx+ones(size(gradscalx))*0.0001; gradorient = zeros(M,N); % unsigned situation: orientation region is 0 to pi. if strcmp(issigned, 'unsigned') == 1 gradorient =... atan(gradscaly./gradscalxplus); gradorient(gradorient<0) = gradorient(gradorient<0)+pi; or = 1; else % signed situation: orientation region is 0 to 2*pi. if strcmp(issigned, 'signed') == 1 idx = find(gradscalx >= 0 & gradscaly >= 0); gradorient(idx) = atan(gradscaly(idx)./gradscalxplus(idx)); idx = find(gradscalx < 0); gradorient(idx) = atan(gradscaly(idx)./gradscalxplus(idx)) + pi; idx = find(gradscalx >= 0 & gradscaly < 0); gradorient(idx) = atan(gradscaly(idx)./gradscalxplus(idx)) + 2*pi; or = 2; else error('Incorrect ISSIGNED parameter.'); end end % calculate block slide step. xbstride = cellpw*nblockw*(1-overlap); ybstride = cellph*nblockh*(1-overlap); xbstridend = N - cellpw*nblockw + 1; ybstridend = M - cellph*nblockh + 1; % calculate the total blocks number in the window detected, which is % ntotalbh*ntotalbw. ntotalbh = ((M-cellph*nblockh)/ybstride)+1; ntotalbw = ((N-cellpw*nblockw)/xbstride)+1; % generate the matrix hist3dbig for storing the 3-dimensions histogram. the % matrix covers the whole image in the 'globalinterpolate' condition or % covers the local block in the 'localinterpolate' condition. The matrix is % bigger than the area where it covers by adding additional elements % (corresponding to the cells) to the surround for calculation convenience. if strcmp(isglobalinterpolate, 'globalinterpolate') == 1