i am unable to zigzag scan image
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i am using this code kindly help me to solve
6 Comments
Walter Roberson
on 31 Mar 2018
Why are you reshaping Red into a 3D array? Why are you reshaping it at all? Why not just ZigZagscan(red) ?
Answers (1)
Guillaume
on 28 Mar 2018
Edited: Guillaume
on 28 Mar 2018
You cannot copy the body of a function into your code and expect it to work like a script. The function needs to be in its own m-file which you call from your script. Hence your script should only be:
X=imread('lena1.jpg');
imshow(X);
v = ZigZagScan(X);
Saying that, this ZigZagScan function is not particularly well written and assumes the input is a square matrix.
Below, a simpler code. Note this is also a function, so you'll have to put it into its own m-file named antizigzag.m
function v = antizigzag(X)
%author: G. de Sercey, University of Brighton
%BSD license
%input: X a 2D matrix, not necessarily square
%output: v a row vector of the anti-diagonals of the matrix scanned in a zigzag fashion
validateattributes(X, {'numeric'}, {'2d'});
X = fliplr(X); %flip X so the anti-diagonals become diagonals
v = arrayfun(@(d) diag(X, d), size(X, 2)-1:-1:1-size(X, 1), 'UniformOutput', false); %get the diagonals
v(1:2:end) = cellfun(@flip, v(1:2:end), 'UniformOutput', false); %flip odd diagonals
v = vertcat(v{:}).'; %concatenate the whole lot in a row vector
end
7 Comments
Walter Roberson
on 30 Mar 2018
jpeg images are 3 dimensional more than 99.9% of the time. You cannot apply zigzag or anti-zigzag routines to them as a whole: you can only apply it to one channel at a time, or else reshape the whole thing as if it were 2D and process the reshaped version. Or convert to grayscale and work with that.
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