Computational Time Difference Between HxWxD Array and H*WxD Array

Hello there.

I have some images which are RGB images or Hyperspectral images. I do some distance calculations for pixels by using those images and pre-calculated cluster centers. Let's say my image has size of 519x540x200 which is shown by Image and there is a matrix has size of 280260x200 which is shown by PixValues and it is created by:

[Height, Width, Dim] = size(Image);
PixValues = zeros(Height * Width, Dim);
for i = 1: Height * Width

      [X , Y] = ind2sub([Height, Width], i);

      PixValues(i,:) = Image(X,Y,:);

end

Which of the below has better performance?

for i = 1: Height
    for j = 1:Width
          Distance = distancecalculation(Image(i,j,:), ClusterCentern);
    end
end

or

for i = 1: Height * Width
    Distance = distancecalculation(PixValues(i,:), ClusterCentern);
end

Answer 1

[KSSV]

You can put a timer and you yourself can come to conclusion...read about tic , toc , timeit