why is my difference image black?...

the program works but my difference image is just black...did i do something wrong? or is there a way to make it visible?

%% 3. Interpolation
ori=imread('body.jpg');                                     %a)Read‘body.jpg’;store into‘ori’ 

sma=imresize(ori,[32 32]);                                  %b)Resize‘ori’ to 32x32;store into‘sma’

nea=imresize(ori,1,'nearest');                              %c)Resize‘sma’ to original using nearest interpolation;store into‘nea’

bil=imresize(ori,1,'bilinear');                             %d)Resize‘sma’ to original using bilinear interpolation;store result into‘bil’

bic=imresize(ori,1,'bicubic');                              %e)Resize‘sma’to original using bicubic interpolation;store result into‘bic’

figure                                                      %f)Display‘ori’,‘nea’,‘bil’,'bic' same figure
subplot(4,1,1);
imshow(ori)
title('ori');
subplot(4,1,2);
imshow(nea)
title('nea');
subplot(4,1,3);
imshow(bil)
title('bil');
subplot(4,1,4);
imshow(bic)
title('bic');

df=imabsdiff(bil,bic);
figure                                                      %g)Display the difference image between bil and bic 
imshow(df,[])
title('difference image');

[Marcel Kreuzberg]

nea, bil and bic are all the same, because you are doing no resizing at all. in the comment you want to resize sma and not ori. try

nea=imresize(sma,[256 256],'nearest'); %c)Resize‘sma’ to original using nearest interpolation;store into‘nea’

bil=imresize(sma,[256 256],'bilinear'); %d)Resize‘sma’ to original using bilinear interpolation;store result into‘bil’

bic=imresize(sma,[256 256],'bicubic'); %e)Resize‘sma’to original using bicubic interpolation;store result into‘bic’

regards

Marcel

[Matt J]

I suggest that you attach df in a .mat file so that we can examine it.

[Rik]

why is my difference image black?...

the program works but my difference image is just black...did i do something wrong? or is there a way to make it visible?

%% 3. Interpolation
ori=imread('body.jpg');                                     %a)Read‘body.jpg’;store into‘ori’ 

sma=imresize(ori,[32 32]);                                  %b)Resize‘ori’ to 32x32;store into‘sma’

nea=imresize(ori,1,'nearest');                              %c)Resize‘sma’ to original using nearest interpolation;store into‘nea’

bil=imresize(ori,1,'bilinear');                             %d)Resize‘sma’ to original using bilinear interpolation;store result into‘bil’

bic=imresize(ori,1,'bicubic');                              %e)Resize‘sma’to original using bicubic interpolation;store result into‘bic’

figure                                                      %f)Display‘ori’,‘nea’,‘bil’,'bic' same figure
subplot(4,1,1);
imshow(ori)
title('ori');
subplot(4,1,2);
imshow(nea)
title('nea');
subplot(4,1,3);
imshow(bil)
title('bil');
subplot(4,1,4);
imshow(bic)
title('bic');

df=imabsdiff(bil,bic);
figure                                                      %g)Display the difference image between bil and bic 
imshow(df,[])
title('difference image');

[Rena Berman]

(Answers Dev) Restored edit

Answer 1

[Matthew Worker]

https://www.mathworks.com/matlabcentral/answers/1467816-why-is-my-difference-image-black#comment_1770511

Answer 2

[Rik]

Posted after a now-deleted comment:

@Matt J @Marcel Kreuzberg Thank you so much i didnt notice that error. It works well now