MATLAB: Error with matrix dimensions

matrix dimensions

Hi, I'm making a code for scene cut detection, but I always get an error for line 14: matrix dimensions must agree… How do I fix this? Thank you.
THRESH = 0.5;
video = mmreader('rhinos.avi');
numFrames = video.NumberOfFrames;
prevHist = zeros(256*3,1);
diffHist= zeros(numFrames,1);
cutInd = 1;
for i = 1 : numFrames
currFrame = read(video, i);
currHistR = imhist(currFrame(:, :, 1));
currHistG = imhist(currFrame(:, :, 2));
currHistB = imhist(currFrame(:, :, 3));
currHist = [currHistR currHistG currHistB];
whos prevHist currHist;
diffHist(i) = sqrt(sum((currHist – prevHist).^2));
if (diffHist(i) > THRESH)
cutFrames(:, :, :, cutInd) = currFrame(:, :, :);
cutInd = cutInd + 1;
end
prevHist = currHist;
end
stem(diffHist);
figure;
montage(cutFrames);

Best Answer

you have two mistake:
prevHist = zeros(256*3,1) 
and 
diffHist(i) = sqrt(sum((currHist - prevHist).^2))
your correct code should be:
clear all
close all
clc;
THRESH = 0.5;
video = mmreader('rhinos.avi');
numFrames = video.NumberOfFrames;
prevHist = zeros(256,3);
diffHist= zeros(numFrames,1);
cutInd = 1;
for i = 1 : numFrames
currFrame = read(video, i);
currHistR = imhist(currFrame(:, :, 1));
currHistG = imhist(currFrame(:, :, 2));
currHistB = imhist(currFrame(:, :, 3));
currHist = [currHistR currHistG currHistB];
whos prevHist currHist;
diffHist(i) = sqrt(sum((currHist(i) - prevHist(i)).^2));
if (diffHist(i) > THRESH)
cutFrames(:, :, :, cutInd) = currFrame(:, :, :);
cutInd = cutInd + 1;
end
prevHist = currHist;
end
stem(diffHist);
figure;
montage(cutFrames);
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