# Getting the maximum value of several matrices loaded from image files.

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Chiara 2013년 11월 12일
댓글: Image Analyst 2013년 11월 15일
I have troubles with the max command applied to images files.
I have N=108 image files tif. Each file corresponds to a matrix. I need to load all the matrix/images and compute a matrix containing the maximum values among the 108 matrices.
My script to read the N=108 files is as follows:
imagelist = dir('*.tif');
N = numel(imagelist);
imdata = cell(1, numel(imagelist));
for k = 1: N
end
I don’t know to compute the “maximum matrix” since imdata contains matrices as cells.
Using
M=max(imdata{k})
indeed I obtain a row vector containing only the maximum values of the first cell.

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### 채택된 답변

Image Analyst 2013년 11월 12일
편집: Image Analyst 2013년 11월 12일
Something like this (untested):
maxImage = zeros(rows, columns, 'uint8');
overallMax = -inf;
for k = 1: N
% Get max of this image.
thisMax = max(thisImage(:));
if thisMax > overallMax
overallMax = thisMax;
end
% Get max image, in case you really meant that. Delete if not.
maxImage = max(maxImage, thisImage);
end
Of course you need to make sure that the dimensions (rows, columns, number of color channels) of all the images match up.
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Image Analyst 2013년 11월 15일
OK good. MATLAB has a rule that integers must be combined with integers of the same class. Usually that comes into play when you're adding or multiplying them but I guess you found out that it also applies when you use the max function. There's no such rule for floating point numbers. Anyway, I'm glad you got it working and accepted the answer.

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### 추가 답변(1개)

Doug Hull 2013년 11월 12일
Do not store the images in cells. Just load each in turn, get the maximum value. Compare this maximum value to the previously found maximum value. Keep the maximum of those two. Repeat until all have been done.
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Chiara 2013년 11월 13일
Thanks for your answer. I cannot convert the cells into matrices though. I’ve tried to automatically upload the 108 tif files I have, using strcat function but doesn’t work. My files are “200301_monthly_adg_443_gsm_P90.tif” The only part varying is the first “200301”. I have already implemented strcat function but not with images.

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