Applying Movmedian Within Cell Array
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Hello,
I have a cell array (2 x 6) called "output", each cell in row #1 {1 -> 6, 2} contains a 1024 x 1024 x 100 matrix. I want to apply movmedian to each cells in row #1. I would like to apply this function in dimension = 3 with window size = 5.
output = cellfun(@movmedian(5,3), output,'uniform', 0);
This is the code that I have come up with so far, however, it produces an "unbalenced or unexpected parenthesis or bracket" error. I am unsure what is causing this error. I am also somewhat unsure how to instruct matlab to perform this operation only on row 1 of the cell array, please help!
Thank you for your time!!
4 个评论
itend
2017-8-24
Image Analyst
2017-8-24
You say C is an array of cells with 2 rows of 6 columns ("2x6").
C(:,1) is a column vector of the 2 cells in column #
C(1,:) is a row vector of the 6 cells in row #1.
C(expression, 2) is a column vector extracted from only the rows identified in "expression" and only from column #2. So it would have either one cell or two cells since there are only two rows.
Not sure what you mean, but it's clear that reading this FAQ item might help: http://matlab.wikia.com/wiki/FAQ#What_is_a_cell_array.3F
itend
2017-8-25
采纳的回答
output(:, 1) = cellfun(@(c) movmedian(c, 5, 3), output(:, 1), 'uniform', 0);
Remember, that cellfun is very nice, but less efficient than a simply loop in general. Try this:
for k = 1:size(output, 1)
output{k, 1} = movmedian(output{k, 1}, 5, 3);
end
I prefer to keep it simple stupid, most of all if it takes less runtime in addition.
5 个评论
Thank you for your help!
There seems, however, to be an issue... after running your code, it doesn't seem to affect "output". I was expecting the matrices to be changed to 1024 x 1024 x 19. I have attached a pic of my matlab screen for reference.
Also, I apologize if I wasn't clear in my initial post. I am interested in applying movmedian to output(1,:).
What do you think?
@itend: There is no reason for apologies. All question concerning Matlab are welcome in the forum and questions for clarifications belong to the standard for solving problems. The communication about a powerful language like Matlab is not trivial, we know this. :-)
Please prefer to post text as text, not as screenshot. When I open the image, I loose the text I'm currently typing.
The output of movmedian has the same size than the input. I assume that you do not want the "moving", but the "block-wise" median over 5 elements:
for k = 1:size(output, 1)
C = output{k, 1};
C = reshape(C, [size(C, 1), size(C, 2), 5, size(C, 3) / 5]);
output{k, 1} = squeeze(median(C, 3));
end
itend
2017-8-24
Image Analyst
2017-8-24
Two questions:
- Why are you using a cell array to store all the frames? I see no need for that.
- Why aren't you using medfilt2() to do a median filter on your images?
itend
2017-8-25
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