Sir i am working on a project in which I had applied 1D DWT on a lena image.The image looks like i attached. Now i want to compress the LL band of the image(the part of the image containing the complete image).

but i am not getting how to take only that part of the image.e.g. if i want to take complete image i will use

i=imread('lena.bmp'); imshow(i); and it will display the complete image.

but now i want only access LL part of the image as I have to apply DPCM only in that part(subband) of the image.