How to vectorize this function

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Faizan Tahir
Faizan Tahir 2016-2-17
评论： Andrei Bobrov 2016-2-18
Hi.
I have a series of images all with the same background but varying foregrounds. I'm looping through all these images and taking median pixel values to calculate the background so I can perform background subtraction. It works well but the code is slow because it contains a double for loop. How can I vectorize the following code?
for x = 1:480
for y = 1:640
median_bg_RedValues(x,y) = median(bg_RedValues(x,y,1:actualNumOfImages));
median_bg_GreenValues(x,y) = median(bg_GreenValues(x,y,1:actualNumOfImages));
median_bg_BlueValues(x,y) = median(bg_BlueValues(x,y,1:actualNumOfImages));
end
end
median_bg_Red/Green/BlueValues is a 480*640 matrix, and bg_Red/Green/BlueValues is a 480x640x40 image, and I want to take the median of each cell's 40 elements (these 40 elements are the different pixel values for the 40 images).
How can I make this faster using vectorization?
Thanks.

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采纳的回答

Andrei Bobrov
Andrei Bobrov 2016-2-17
median_bg_RedValues = median(bg_RedValues, 3);
median_bg_GreenValues = median(bg_GreenValues,3);
median_bg_BlueValues = median(bg_BlueValues, 3);
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