HOG descriptor for multiple people detection - matlab

Question

I am doing a real-time people detection using HOG-LBP descriptor and using a sliding window approach for the detector also LibSVM for the classifier. However, after classifier I never get multiple detected people, sometimes is only 1 or might be none. I guess I have a problem on my classification step. Here is my code on classification:
label = ones(length(featureVector),1);
P = cell2mat(featureVector);
% each row of P' correspond to a window
% classifying each window
[~, predictions] = svmclassify(P', label,model);
% set the threshold for getting multiple detection
% the threshold value is 0.7
get_detect = predictions.*[predictions>0.6];
% the the value after sorted
[r,c,v]= find(get_detect);
%% Creating the bounding box for detection
for ix=1:length(r)
rects{ix}= boxPoint{r(ix)};
end
if (isempty(rects))
rects2=[];
else
rects2 = cv.groupRectangles(rects,3,'EPS',0.35);
end
for i = 1:numel(rects2)
rectangle('Position',[rects2{i}(1),rects2{i}(2),64,128], 'LineWidth',2,'EdgeColor','y');
end
For the whole my code, I have posted here : [HOG with SVM] (sliding window technique for multiple people detection)
I really need a help for it. Thx.

Answer 1

If you have problems wiith the sliding window, you can use this code:
topLeftRow = 1;
topLeftCol = 1;
[bottomRightCol bottomRightRow d] = size(im);
fcount = 1;
% this for loop scan the entire image and extract features for each sliding window
for y = topLeftCol:bottomRightCol-wSize(2)
for x = topLeftRow:bottomRightRow-wSize(1)
p1 = [x,y];
p2 = [x+(wSize(1)-1), y+(wSize(2)-1)];
po = [p1; p2];
img = imcut(po,im);
featureVector{fcount} = HOG(double(img));
boxPoint{fcount} = [x,y];
fcount = fcount+1;
x = x+1;
end
end
lebel = ones(length(featureVector),1);
P = cell2mat(featureVector);
% each row of P' correspond to a window
[~, predictions] = svmclassify(P',lebel,model); % classifying each window
[a, indx]= max(predictions);