10 lllo n !ti,l. , o.,   ENERAL ALI MAINENAN MOE ORMOTON ITR AERMARIN Isao Echizen,1 Hiroshi iua, a Arai,2 Hiroyuki iua,  h Takeuchi3 1Systems Development Laboratory, Hitachi, Ltd. 2Digital Media Products Division, Hitachi, Ltd. 30igital Media Systems R&D Division, Hitachi, Ltd. ABSTRACT Because the pi cture quality of watermarked motion pictures must not he degraded by the watenuarldng, this paper describes a new modulc that controls watcl'markin1 pl'OC esses, The module s a new human si1ht model t o optimize watennark strength ' each frame of a motion picture, and it pre vents fickel'ing hy limiting the framc-to fmme change in watermarl{ strength. Ano thel' advantage of this module is that it can  s in a wide I'ange of waternuuki ng systems. The effectiveness of the pro[)oscd module has heen demonstrated in fve wa termat'king syst(�ms. . Intr'oduction Digi tal watermarking is a key technology  protecting the copyrights  digital motion pic tures. It embeds cO]1ycontrol information in motion pictures by chngi ng t constituent. still pictures (frames) s l i ghtly. Because the protected otion pictures arc valuable  ark i ng must. not degrade picture qual i ty. Mo tion pi cture watermarking has been studied in tensively r I], but techniques for maintaining picture qualit. y have not yet been established because (j) the underlying techniques f wa termarking still pi ctures were insufficient, (2) the problems inherent  motion pictu res were t treated sufficicntly, and (3) thc prcvious methods e specific to individual systems (lacked generality). This paper ef de scribes a ee quality nn module (GQM) that solves these problems. L Previous Methods for Maintainin g Picture Quality J<igure  shows an example or motion pict ure watermarking. Watermarks (WMs) arc usually embedded into c e ( l l picture) of thc motion picture. ()i r.··· w�'1 �eteCtiOLl �J-.- rCDpyrighl' �lI()nllati � o WaLenllark�lI  I: I�Xlllll[llc of Illolion picture waterillarking. Methods  waterlllarking mol ion pictures  be classified into lwo types: those changi ng pixel values and those changing frequency co' efficienls. This  treats  methods changi ng pixel values. 2.l Requirements Mot i on picture watermarks should tlot degrade the picture qu al ity. That is, they should not in t.erfere wi th r cn lj oy ment or  mot.i on pie lures. They should nonetheless be robust nouh  be reliably dctected alkr comlllon image processingprocedues such as MPEG, and they s houl d never be founcl in unmarked pictures. We concer maintaining picture qual ity and describe the issue.> of the previous methods. n  I, I '),)) 000(' $10.00" 1 EEE