Can anybody help me to solve the error from this code function it will be a nice help

 clc;
 close all;
 clear variables;
 clear all;
function inv_transformed_img= KT(I)
 I=imread("cameraman.tif");
I=im2double(I);
m=1;
for i=1:8:256
    for j=1:8:256
        for x=0:7
            for y=0:7
            img(x+1,y+1)=i(i+x,j+y);
            end
        end
            k=0;
            for l=1:8
                img_expect{k+1}=img(:,l)*img(:,l)';
                k=k+1;
            end
            imgexp=zeros(8:8);
            for l=1:8
                imgexp=imgexp+(1/8)*img_expect{l};%expectation of E[xx']
            end
            img_mean=zeros(8,1);
            for l=1:8
                img_mean=img_mean+(1/8)*img(:,l);
            end
            img_mean_trans=img_mean*img_mean';
            img_covariance=imgexp - img_mean_trans;
            [v{m},d{m}]=eig(img_covariance);
            temp=v{m};
             m=m+1;
            for l=1:8
                v{m-1}(:,l)=temp(:,8-(l-1));
            end
             for l=1:8
           trans_img1(:,l)=v{m-1}*img(:,l);
             end
           for x=0:7
               for  y=0:7
                   transformed_img(i+x,j+y)=trans_img1(x+1,y+1);
               end
           end
mask=[1 1 1 1 1 1 1 1 
      1 1 1 1 1 1 1 1 
      1 1 1 1 1 1 1 1 
      1 1 1 1 1 1 1 1 
      1 1 1 1 1 1 1 1 
      1 1 1 1 1 1 1 1 
      1 1 1 1 1 1 1 1 
      1 1 1 1 1 1 1 1 ];
  trans_img=trans_img1.*mask;
           for l=1:8
           inv_trans_img(:,l)=v{m-1}'*trans_img(:,l);
           end
            for x=0:7
               for  y=0:7
                  inv_transformed_img(i+x,j+y)=inv_trans_img(x+1,y+1);
               end
           end
          end
end
  figure(1)
  imshow(transformed_img);
  figure(2)
  imshow(inv_transformed_img);
 end

[madhan ravi]

Upload cameraman.tif file.

[shivu P]

uploadded already

[Guillaume]

It's not been uploaded. However, assuming that it's the standard 'cameraman.tif' that comes with matlab, it's not needed since as said, it comes with matlab.

What is needed however, is a description of "the error from this code function". If it does issue an error, then what is the whole text of the error (everything in red). If it does not produce the right result, then what does it produce and what was wanted instead.

[Guillaume]

In addition, why does the function takes input I to immediately overwrite that input by an image.

Answer 1

[Guillaume]

If "the error from this code function" is caused by imread, that would be because imread does not accept string inputs, only char array:

I = imread('cameraman.tif');  %use ' instead of "

[Walter Roberson]

I imagine that restriction will be lifted sooner or later.

[Guillaume]

Yes, I'm surprised it's already not supported. Strangely enough, if the second time in a few days that I see somebody on the forum passing a string to imread or imwrite.

Answer 2

[Walter Roberson]

You have

for i=1:8:256

so i is a scalar.

Then you have

            img(x+1,y+1)=i(i+x,j+y);

so you are trying to index i as if it were a 2D array.

Your error about duplicate function names is happening because your code

 clc;
 close all;
 clear variables;
 clear all;

is converting the .m file from being a function into being a script. Your script file name is KT.m . It is not permitted to have a function named the same thing as the script name when you have a function inside a script.

What you should be doing is removing the four lines I indicated.