MATLAB: Shadow detection and removal based on HSV color model.

background subtractionimage processingshadow detectionvideo processing

Index exceeds matrix dimensions.
Error in Bpos (line 37) w= (cfv(i,j)/pv(i,j));
Code is here:
mov = VideoReader('C:/Users/research01/Desktop/Walking.avi');
p=imread('C:/Users/research01/Desktop/1234.png');
p=rgb2hsv(p);
ph=p(:,:,1);
ps=p(:,:,2);
pv=p(:,:,3);
alphaV=0.2;
betaV=0.8;
opFolder = fullfile('F:\imagelab', 'Bpos');
if ~exist(opFolder, 'dir')
mkdir(opFolder);
end
numFrames = mov.NumberOfFrames;
numFramesWritten = 0;
for t = 1 : numFrames
currFrame = read(mov, t);
currFrame=rgb2hsv(currFrame);
figure;imshow(currFrame);
cfh=currFrame(:,:,1);
figure;
imshow(cfh);
cfs=currFrame(:,:,2);
figure;imshow(cfs);
cfv=currFrame(:,:,3);
figure;imshow(cfv);
[m,n]=size(currFrame);
single=zeros(m,n);
for i=1:m
    for j=1:n
%        a=cfv(i,j);
%        progIndication = sprintf('Wrote frame  %d.',a);
%        disp(progIndication);
       w= (cfv(i,j)/pv(i,j));
       progIndication = sprintf('Wrote frame  %d.',w);
       disp(progIndication);
       sat=cfs(i,j)-ps(i,j);
        progIndication = sprintf('sat frame  %d.',w);
       disp(progIndication);
       hue=cfh(i,j)-ph(i,j);
        progIndication = sprintf('hue frame  %d.',w);
       disp(progIndication);
       if(w>=alphaV && w<=betaV && sat<=-0.3 && hue <=0.2)
           single(i,j)=1; 
       else
            single(i,j)=0;
       end
    end
end
imshow(single);
opBaseFileName = sprintf('%3.3d.png', t);
opFullFileName = fullfile(opFolder, opBaseFileName);
imwrite(single, opFullFileName, 'png');
end

Best Answer

Evidently your still image does not have the same number of rows and columns as your video. You should really check for that before you begin processing. You want to write robust code don't you? Alert your users if that's the case with errordlg().
message = sprintf('Image rows = %d\nImage columns = %d\nVideo rows = %d\nVideo columns = %d',...
rows, columns, videoRows, videoColumns);
uiwait(errordlg(message));
return;
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