This filtering results {HEAD ~ such an image} that the mean square error of {TAIL ~ the restored image f′} from the input image f is minimal 
This filtering results { HEAD ~ such an image } that the mean square error of { TAIL ~ the restored image f′ } from the input image f is minimal
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH