Storing CWT of each row of image in a Cell

Question

I want to compute the morlet wavelet of each row of 480X480 image. I have to save the output of the transform of each row which is a 2d array(matrix).

Then i will be taking the average all 480 2d matrices i have to get one final plot of the average.

clc;
close all;
clear all;
I=imread('lena.jpg');
J=rgb2gray(I);
%K=J(1:480)
%coefs = cwt(K,1:128,'morl','plot');


coefs = cell(480,1);
for i = 1:480
   K=J(i,:);
coefs(i) = cwt(K,1:128,'morl');
end  

Here i want to take the avg of the 480 coeff matrices. Here am getting the error

Conversion to cell from double is not possible.

Error in soilwave (line 12) coefs(i) = cwt(K,1:128,'morl');

Could anyone suggest a better method or tweaks to this.

Answer 1

Cell arrays are practical if you need to store elements that have inconsistent format or dimensions, but for what you are trying to do, a 3D array is easier to work with. Here is what I would do:

Preassign a 3D array:

coefs = zeros(128, size(J, 2), size(J,1));

then compute and populate the stack:

for ii = 1:size(J, 1)
   K=J(ii,:);
   coefs(:,:,ii) = cwt(K,1:128,'morl');
end  

Finally, compute the mean along the third dimension:

MeanCoeff=mean(coefs, 3);