I am getting the error Missing variable or function when I am trying to implement a code on 2 dimensional DWT on images in MATLAB 7. The code is given below.

f = imread('Region_of_interest.bmp');
imshow(f)
 wname = 'sym4';
[CA,CH,CV,CD] = dwt2(X,wname,'mode','per');
subplot(211)
imagesc(CV); title('Vertical Detail Image');
subplot(212)
imagesc(CA); title('Lowpass Approximation');

Sir, kindly help me.

thanks and regards

Debarpita Chaudhuri.

Answer 1

[Walter Roberson]

dwt2() is part of the Wavelet toolbox. You would need to have that installed and licensed.

[Debarpita Chaudhuri]

Sir, I do have wavelet toolbox. Is there any chance that the image variable X or f is not treated as a matrix right away. Do I need to add some code to change the the image variable into a 2-D Matrix so that dwt2() may give a proper output? thanks and regards Debarpita Chaudhuri.

[Debarpita Chaudhuri]

Sir, my code is running now with the image of barbara. The code is given below

if true
  % load woman;
wname = 'sym4';
[CA,CH,CV,CD] = dwt2(X, wname, 'mode', 'per');
subplot(211)
imagesc(CV); title('Vertical Detail Image');
colormap gray;
subplot(212)
imagesc(CA); title('Lowpass Approximation');
end

How do I edit this code to input a bmp image of my own, as for example the image given here.