compare_nla.m

脊波工具和相关实验以及有关实验数据

% Compare NLA between FRIT and WAVE2

% Object image of size 257x257
im = imread('obj.png'); 
im = double(im) / 256;

% Parameters
wname = 'sym4';
nlevs = 8;

ncoefs = 2.^[5:8];

% FRIT 
frit_im = frit_nla(im, wname, ncoefs); 

% WAVE2
wave_im = wave2_nla(im(1:end-1,1:end-1), wname, nlevs, ncoefs);

% range = [0, 1];
range = [-0.5, 1];

for k = 1:length(ncoefs)        
    % WAVE2
    figure(1), clf;
    set(gcf, 'Name', 'DWT2')
    colormap('gray');

    imagesc(wave_im{k}, range);
    axis image, 
    axis off,
    title(sprintf('%d coefficients (SNR = %0.2f dB)', ...
		  ncoefs(k), SNR(im(1:end-1,1:end-1), wave_im{k})));
  
    % FRIT
    figure(2), clf;
    set(gcf, 'Name', 'FRIT')
    colormap('gray');

    imagesc(frit_im{k}, range);
    axis image, 
    axis off,
    title(sprintf('%d coefficients (SNR = %0.2f dB)', ...
    		  ncoefs(k), SNR(im, frit_im{k})));
      
    disp('Hit any key to continue');
    pause
end