Ndi kupita patsogolo kosalekeza kwaukadaulo wazidziwitso, zolemba zamagetsi zikukhala zosavuta komanso zodziwika bwino, zomwe zikulamulira zamapepala azikhalidwe. Chifukwa chake, ndikofunikira kuyika patsogolo chitetezo chazidziwitso osati pamapepala achikhalidwe komanso pamakalata apakompyuta. Kampani iliyonse yayikulu yomwe imakhala ndi zinsinsi zazamalonda, zaboma, ndi zinsinsi zina zimafuna kuletsa kutayikira kwa zidziwitso ndi kusokoneza zidziwitso zachinsinsi, ndipo ngati kutayikira kwazindikirika, chitanipo kanthu kuti muyimitse kutulutsako ndikuzindikira wolakwayo.
Pang'ono ndi zosankha zachitetezo
Kuti akwaniritse ntchitoyi, zinthu zina zachitetezo zimayambitsidwa. Zinthu izi zingaphatikizepo ma barcode, zilembo zowoneka, zolemba zamagetsi, koma zochititsa chidwi kwambiri ndi zilembo zobisika. Ma watermark ndi ena mwa zitsanzo zodziwika bwino; angagwiritsidwe ntchito pamapepala kapena kuwonjezedwa asanasindikizidwe. Si chinsinsi kuti osindikiza amawonjezera ma watermark awo (madontho achikasu ndi zizindikiro zina) akamasindikiza, koma tiwonanso zinthu zina zomwe zingawoneke pakompyuta kapena pamalo ogwirira ntchito. Zinthu zakalezi zimapangidwa ndi pulogalamu yapaderadera yomwe imaphimba zinthu zakale pamalo ogwirira ntchito, kumachepetsa mawonekedwe ake komanso osasokoneza kayendedwe ka wogwiritsa ntchito. Matekinoloje awa ali ndi mizu yakale muzochitika zasayansi ndi ma aligorivimu popereka zidziwitso zobisika, koma ndizosowa kwambiri masiku ano. Njirayi imagwiritsidwa ntchito makamaka m'magulu ankhondo ndi pamapepala, kuti azindikire mwamsanga antchito osakhulupirika. Matekinoloje awa akungoyamba kumene kutengedwa ndi gawo lazamalonda. Ma watermark owoneka tsopano akugwiritsidwa ntchito kwambiri kuteteza kukopera kwa mafayilo osiyanasiyana atolankhani, pomwe osawoneka ndi osowa. Komabe, iwonso ndi omwe amapanga chidwi kwambiri.
Zosungidwa zachitetezo
Ma watermark osaoneka amapanga zinthu zakale zosiyanasiyana zomwe mwina sizingawonekere m'maso mwa munthu kapena zobisika pachithunzichi ngati timadontho tating'ono kwambiri. Timayang'ana kwambiri zinthu zowoneka, popeza zosawoneka zitha kukhala kunja kwa danga lodziwika bwino la zowunikira zambiri. Zinthu zakalezi ndizofunika kwambiri chifukwa cha kuchuluka kwake kosawoneka. Komabe, ndizosatheka kupanga ma watermark a digito kuti asawonekere. Zikaphatikizidwa mu chithunzicho, zimabweretsa zosokoneza zina mumtsuko, ndikupanga zinthu zakale. Tikambirana mitundu iwiri ya zinthu:
- Cyclic
- Chisokonezo (choyambitsidwa ndi kusintha kwa zithunzi)
Mipangidwe ya cyclic ndi ndondomeko yeniyeni yokhazikika ya zinthu zobwerezabwereza zomwe zimabwerezedwa kangapo pazithunzi zowonekera (mkuyu 1).
Zowonongeka zowonongeka zimatha kuyambitsidwa ndi mitundu yosiyanasiyana ya kusintha kwa fano lapamwamba (mkuyu 2), mwachitsanzo, kuyambitsidwa kwa hologram.
Chithunzi cha 1 Cyclic artfacts
Mkuyu 2 Zinthu zakale zosokoneza
Tiyeni tiyambe ndi kuyang'ana njira zozindikirira zinthu zopangidwa ndi cyclic. Zinthu zoterezi zingaphatikizepo:
- ma watermark omwe amabwerezedwa pazenera lonse
- machitidwe a binary
- gulu la mfundo mwachisawawa mu gulu lililonse selo
Zolemba zonse zomwe zalembedwa zimayikidwa mwachindunji pazomwe zikuwonetsedwa. Chifukwa chake, amatha kudziwika pozindikira kunyanyira kwanuko kwa histogram panjira iliyonse yamtundu ndikudula mitundu ina yonse. Njirayi imaphatikizapo kugwira ntchito ndi kuphatikizika kwa zinthu zakumaloko panjira iliyonse ya histogram. Vuto liri pakupeza kunyanyira kwanuko pachithunzithunzi chovuta kwambiri chokhala ndi zambiri zosintha kwambiri; histogram imawoneka ngati macheka kwambiri, zomwe zimapangitsa kuti njirayi isagwiritsidwe ntchito. Zosefera zosiyanasiyana zitha kugwiritsidwa ntchito, koma zimabweretsa zosokoneza zawo, zomwe zimatha kupangitsa kuti asazindikire watermark. Njira ina ndikuzindikira zinthu zakalezi pogwiritsa ntchito zida zina zam'mphepete (mwachitsanzo, Canny edge detector). Njirazi ndizoyenera kuzinthu zakale zomwe zimakhala ndi masinthidwe akuthwa kwambiri. Zowunikira zimatha kuwunikira ma contour azithunzi kenako ndikusankha mitundu yamitundu yomwe ili mkati mwamizere kuti chithunzicho chizisiyanitsidwa kuti chizisiyanitsenso zinthu zakale. Komabe, njirazi zimafunika kukonzedwa bwino kuti zizindikire mikombero yomwe mukufuna, komanso kusinthana kotsatira kwa chithunzicho potengera mitundu yamitundu yomwe mwasankha. Ma algorithms awa amawonedwa ngati osadalirika ndipo amakonda kugwiritsa ntchito ma aligorivimu okhazikika omwe sadalira mtundu wa zigawo zamtundu wa chithunzicho.
Chithunzi cha 3 Watermark mutatha kutembenuka
Ponena za chipwirikiti chomwe takambirana kale, ma algorithms ozindikira adzakhala osiyana kwambiri. Zinthu zopangidwa ndi chipwirikiti zimapangidwa ndi kukulitsa watermark pachithunzichi, chomwe chimasinthidwa pogwiritsa ntchito masinthidwe amtundu wina (mwachitsanzo, kusinthika kwa Fourier). Zopangidwa kuchokera ku masinthidwe otere zimagawidwa pazenera lonse, zomwe zimapangitsa kuti zikhale zovuta kuzindikira mawonekedwe. Chifukwa chake, watermark ipezeka pachithunzichi chonse ngati "zachisawawa". Kuzindikira watermark yotere kumaphatikizapo kusintha mwachindunji chithunzicho pogwiritsa ntchito ntchito zosintha. Zotsatira zosinthika zikuwonetsedwa mu chithunzi (mkuyu 3).
Komabe, zovuta zingapo zimabuka zomwe zimalepheretsa kuzindikira kwa watermark pansi pamikhalidwe yocheperako. Kutengera mtundu wa kusinthika, zovuta zosiyanasiyana zitha kubuka, monga kulephera kuzindikira chikalata chojambulidwa pamtunda wotsetsereka, kapena chithunzi chosawoneka bwino, kapena chithunzi chojambulidwa chomwe chimasungidwa mufayilo yotayika. Zinthu zonsezi zimasokoneza kuzindikira kwa watermark. Pankhani ya chithunzi cha oblique, masinthidwe ovuta kwambiri kapena masinthidwe amtundu wa affine ayenera kugwiritsidwa ntchito, koma palibe njira yomwe imatsimikizira kuchira kwathunthu kwa watermark. Poganizira za kujambulidwa kwazithunzi, mavuto awiri amabuka: yoyamba ndikusokonekera panthawi yomwe ikuwonetsedwa pazenera, ndipo yachiwiri ndikusokoneza pakusunga chithunzicho. Yoyamba ndiyovuta kuwongolera chifukwa chakuti matrices owunikira amasiyana mumtundu, ndipo chifukwa chosowa mtundu wina, amaphatikiza mitundu kutengera mawonekedwe awo amtundu, potero amabweretsa zosokoneza mu watermark yokha. Yachiwiri ndiyovuta kwambiri, chifukwa mutha kusunga chithunzi chamtundu uliwonse ndipo, motero, kutaya gawo lamitundu, chifukwa chake, titha kutaya watermark yokha.
Nkhani zokhazikitsa
Pali ma aligorivimu ambiri oyika ma watermark omwe alipo lero, koma palibe amene amatsimikizira 100% kuzindikira kwa watermark atayikidwa. Vuto lalikulu ndikuzindikira kuchuluka kwamasewera omwe angabwere pazochitika zilizonse. Monga tanena kale, ndizovuta kupanga algorithm yodziwika yomwe imayambitsa zosokoneza zonse zomwe zingatheke ndikuyesa kuwononga watermark. Mwachitsanzo, ngati fyuluta ya Gaussian ikugwiritsidwa ntchito pa chithunzi chamakono, ndipo zojambula pachithunzi choyambirira zinali zazing'ono komanso zosiyana ndi zakumbuyo, zingakhale zosatheka kuzizindikira, kapena gawo la watermark lidzatayika. Ganizirani za chithunzi, chomwe chikhoza kuwonetsa moiré (mkuyu 5) ndi "gridi" (mkuyu 4). Moiré imachitika chifukwa cha kusinthasintha kwa matrix owonetsera komanso kusakhazikika kwa matrix a chipangizo chojambulira; muzochitika izi, zithunzi ziwiri zonga gridi zimayikidwa pamwamba. Ma mesh amatha kubisa pang'ono zojambula za watermark ndikuyambitsa zovuta zozindikirika, pomwe moiré, mwa njira zina zophatikizira ma watermark zimapangitsa kuti zikhale zosatheka kuzizindikira, chifukwa zimabisa gawo lachithunzicho ndi watermark.
Chithunzi cha 4 gridi
Chithunzi 5 Moire
Kuti muwongolere kuzindikira kwa watermark, ndikofunikira kugwiritsa ntchito ma aligorivimu potengera ma neural network odziphunzira, omwe angaphunzire kuzindikira zithunzi za watermark panthawi yogwira ntchito. Pali zida zambiri za neural network ndi ntchito zomwe zilipo, monga za Google. Ngati angafune, munthu atha kupeza zithunzi zofananira ndikuphunzitsa neural network kuti izindikire zinthu zakale zofunika. Njirayi imapereka mwayi wabwino kwambiri wozindikira ma watermark osokonekera kwambiri, koma imafunikira mphamvu yapakompyuta yofunikira komanso nthawi yayitali yophunzitsira kuti azindikire molondola.
Chilichonse chofotokozedwa chikuwoneka chophweka, koma mukamazama kwambiri muzinthuzi, mumazindikiranso kuti kuzindikira ma watermark kumafuna nthawi yochuluka kuti mugwiritse ntchito ma aligorivimu, komanso nthawi yochulukirapo kuti muyesere kuti mukhale ndi chidziwitso chofunikira pa chithunzi chilichonse.
Source: www.habr.com
