File list:
Mo phong Watermark
.................\dct2_embed_mod.m
.................\dct2_recover_mod.m
.................\dct2_watermarked_mod.bmp
.................\pn_period.m
.................\pn_test.m
.................\psnr.m
.................\_copyright.bmp
.................\_key.bmp
.................\_lena_std_bw.bmp
