Set to zero largest wavelet coefficients.

Hi everybody,

I am reading the book "A Mathematical Introduction to Compressive Sensing".

The next example took my attention.

I cant believe it! So I am trying to repeat the above example.

There is not more information about the type of wavelets used to modify the 99% of the coeffcients.

So I computed 'haar DWT' coefficients of the cameraman image as next:

image = imread('cameraman.tif');
wavename = 'haar';
[cA,cH,cV,cD] = dwt2(im2double(image),wavename);

Then, I set to zero high frequency sub-bands coefficients and apply the inverse DWT.

 cH(:) = 0;
 cV(:) = 0;
 cD(:) = 0;
mod_image = idwt2(cA,cH,cV,cD,wavename);

I only modified the 75% of the total coefficients, however the recovered image loses a lot of quality (Compared with the example, where 99% of the coefficients are set to zero).

What should I do to repeat the example?

Should I use a different wavelet type?

How should I modify the largest coefficients?

Thank you very much for your help!