I decomposed the image (256*256) using DWT and obtained the four sub bands of each 128 *128. Now I am taking the three high frequency sub bands of each (128*1)to be measured with Measurement matrix (100*128). So therefore i would get three resultant measured vectors.This is Compression.
Reconstruction:
I would use the low frequency band(128*128) and the 3 high frequency band(128*1) using OMP to reconstruct the image.
Clarifications:
How to convert the one high frequency sub band (128 *128) into one measured vectors (128*1) ?