how to write program denoising signal using wavelet

I have denoised a signal using wavelet,as wavelet will give the TF information.I want to plot time-frequency plane.There is command like imagesc to plot TF plane,but I do not know how to use that command to plot TF plane.Can anyone help me out ?this is my prgm:x1=0.000001*cos(2*pi*10*t)+0.000004*cos(2*pi*20*t)+0.000007*cos(2*pi*40*t)+0.000008*cos(2*pi*60*t);fs=10000 i have add wgn noise to this signal. xden=wden(Iwn,'sqtwolog','s','mln',6,'dmey');