image fitting problem white and black background

hi all , i use codes below for rgb image denoising the processed image appeared white and black background what is the error ? [f,map]=imread('friend.jpg');

 imshow(f,map);title('original image');
 warning('off', 'Images:initSize:adjustingMag');
 display('enter the noise varience:  ');
va=input('enter between 0.01 to 0.09:   ');
g=imnoise(f,'gaussian',0,va);

        imshow(g,map);title('noisy image');
        [thr,sorh,keepapp] = ddencmp('den','wv',g);
        xd = wdencmp('gbl',g,'db4',2,thr,sorh,keepapp);
        level=2;
        wv='db4' ;
        %[c,s]=wavefast(g,level,wv);
%subplot(2,2,3),wave2gray(c,s,8);title('decomposed structure');

%subplot(2,2,4),xd=uint8(xd);

imshow(xd,map);title('denoised image'); %subplot(2,2,2),imshow(xd);title('denoised image');