function ImageWT(wt,n,s_scale,l_scale)
    % 畫出信號的小波變換結果
    scale = l_scale-s_scale+1;
%    ytix = linspace( log2(l_scale)-log2(n),log2(s_scale)-log2(n),l_scale-s_scale+1);
    ytix = linspace( log2(l_scale),log2(s_scale),l_scale-s_scale+1);
    xtix = linspace(0,n,n);
    for k=1:scale,
        amax = max(wt(k,:));
        amin = min(wt(k,:));
        wt(k,:) = ((wt(k,:))-amin) ./ (amax-amin) .*256;
    end
    image(xtix,ytix, flipud(wt));
    axis('ij');
    xlabel('');
    ylabel('log2(s)'); 
    str = sprintf('colormap(1-%s(256))','gray');
    eval(str);