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