Siv tshuab tshiab tiv thaiv kev ua haujlwm: cov ntaub ntawv pov tseg (ntawm)
Peb yog ib lub tuam txhab luam ntawv loj hauv Shenzhen Tuam Tshoj. Peb muaj cov phau ntawv luam tawm, phau ntawv xov xwm luam ntawv, phau ntawv luam ntawv, phau ntawv nyuaj, phau ntawv luam tawm, phau ntawv luam tawm, phau ntawv luam tawm, lub thawv ntim, daim qhia ntawv, txhua yam ntawm PVC, cov khoom ntawv, cov ntawv me, cov ntawv nplaum, tag nrho hom tshwj xeeb ntawv xim luam tawm khoom, kev ua si cardand li ntawd.
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Nrog rau cov kev siv technology thiab kev siv tshuab computer technology sai, txoj kev tshaj tawm thiab kev paub ntawm cov ntaub ntawv tau ua cov kab mob yooj yim thiab yooj yim, thiab txhawb kev tsim kho cov xov xwm kev sib txauv. Txawm li cas los xij, vim yog qhov yooj yim ntawm kev cia, kev luam thiab kev tshaj tawm ntawm cov xov xwm digital, ntau cov xov xwm digital feem ntau yog cai luam thiab tawm mus thaum uas tau kis rau hauv ib daim ntawv foos. Txawm li cas los xij, qee cov kev yees encryption technologies tsis tuaj yeem tiv thaiv kev lag luam thiab cuam tshuam rau cov ntaub ntawv xa tawm. Hauv qhov teeb meem no, raws li kev sib txuas lus ntawm kev siv technology, cov kev siv tshuab raj (Digital Watermarking) tau los ua.
Txawm tias cov xov xwm tawm digital los ua ntau dua, tau ntev, feem ntau ntawm cov ntaub ntawv nraaj yuav tshwm sim thiab nthuav tawm hauv kev luam. Txawm li cas los xij, qhov kev coj cwj pwm uas pheej nce ntxiv tau coj cov kev cov nyom tshiab rau txoj kev tiv thaiv kev txhaum. Nyob rau hauv rooj plaub no, kev siv cov xov tooj cua txuas nrog cov khoom siv hluav taws xob thiab cov nqi qis rau kev tiv thaiv ntawm cov teeb meem luam tawm yog lub ntsiab lus tshiab thiab kev taw qhia.
Cov kev siv cov xov xwm tshiab yog cov xov tooj tshiab uas siv cov ntaub ntawv xov xwm, cov suab lus, thiab cov yeeb yaj duab. Mus cuag kev tivthaiv thiab lwm yam. Nyob rau tib lub sijhawm, lub cim ntawm cov ntaub ntawv no tsis cuam tshuam txog kev siv tus nqi tseem ceeb, thiab nws tsis yooj yim rau kev xav los ntawm tib neeg txoj kev xav thiab cov ntaub ntawv qub tau muab rho tawm los ntawm ib txoj kev rov qab. Los ntawm extracting cov ntaub ntawv uas muab zais, koj tuaj yeem tshawb xyuas qhov tseeb thiab kev ncaj ncees ntawm tus creator thiab buyer ntawm cov ntsiab lus. Ib txoj kev uas yooj yim rau embedded watermark hauv ib qho duab yuav pom tau ua ib qho pom tsis pom kev tsis pom kev (watermark) hauv qab tus muaj zog tom qab (piv txwv, tus duab thawj). Txij thaum kev daws teeb meem ntawm tib neeg lub cev (HumanVisual System, HVS) tsuas siv tau yog tias qhov ntev ntawm qhov teeb meem ntawm lub siab tshaj plaws ntawm qhov sib txawv ntawm qhov sib txawv ntawm HVS, HVS tsis tuaj yeem hnov qhov teeb meem. Yog li, hauv qhov sib npaug ntawm HVS qhov kev hloov, tej yam kev hloov rau daim duab thawj (ntxiv lub raj xa khoom) tuaj yeem ua tiav los ntawm kev nkag qee cov ntaub ntawv zais tsis tas hloov qhov kev pom zoo. Feem ntau, muaj qee cov kev cai yooj yim rau cov kev ua luam dej: 1 imperceptibility; 2 qhov ua kom pom tseeb: 3 kev ruaj ntseg: 4 kev ruaj ntseg.
Tus qauv digital watermark muaj ob theem: lub embedding ntawm lub watermark thiab lub extraction los yog nrhiav kom pom ntawm lub watermark. Cov qauv tsim ntawm theem ntim cov lus mas yob ua ob qho teeb meem: 1 lub cim ntawm cov xov xwm qis. Nws yuav ua tau ib txoj hlua ntawm cov pseudo-random tooj, cov paib, cov ntawv, cov duab, thiab lwm yam., Los yog nws tuaj yeem tsim los ntawm encrypting cov hlua, icons, etc. txog tus sau: 2 embedded algorithm. Lub hom phiaj ntawm lub tswv yim emblem yog nrhiav kev sib haum xeeb ntawm cov kev ua luam dej hauv kev tsis txaus ntseeg thiab kev ua haujlwm.
Lub sij hawm uas paub tias nws yog tsim los tsim ib qhov kev tshawb nrhiav algorithm coj los siv rau txheej txheem embedded. Qhov tshwm sim ntawm kev kuaj pom yog tus thawj watermark (xws li cov hlua lossis cov cim) lossis qhov kev kuaj pom raws li cov txheej txheem sib txawv los txiav txim seb muaj qhov xwm txheej lossis tsis muaj lub raj xaij. Lub hom phiaj ntawm cov tswv yim txhim kho yog txo cov kev tsis txaus siab thiab kev txiav txim tsis tuaj yeem ua kom tsawg. Thiaj li yuav ua rau kom tsis muaj kev nyuaj ntawm kev tshem cov khoom nruab ntug, feem ntau watermarking schemes tam sim no siv qhov tseem ceeb thaum tsuas yog tus tswv los yog tus yuam sij siv los nyeem cov ntawv pov thawj.
Muaj ntau txoj kev rau kev ua luam dej. Raws li txoj kev sib txawv ntawm cov xov xwm foob pob, cov watermarks yuav muab faib ua ob pawg: qhov chaw sau cov ntaub ntawv tawm thiab cov khoom xa mus hloov ua cov luam dej. Raws li seb tus watermark yuav tsum tau txhawm rau txhom tau lub watermark, cov tshuab digital watermark yuav muab faib ua peb hom: ntiav kev siv tshuab raj, kev siv tshuab ua luam dej nrab thiab kev siv tshuab raj rau pej xeem.
1, cov kev cai tshwj xeeb
Txij li cov duab nruam yuav tsum tau muab tso rau hauv kev luam tawm kom tau ib daim duab ntawm ib nrab ntawm cov duab, cov txheej txheem digital watermarking yog siv los hloov tus lej ntawm tus lej hauv cheeb tsam ntawm cov ntawv xov xwm, uas yog, cov dots los sawv cev rau kev hloov txheej thiab xim ntawm cov duab nruam tas mus li. Hauv kev tiv thaiv cov teeb meem ntawm cov ntawv sau tawm, nws yog qhov yuav tsum tau xav txog cov txheej txheem ntawm kev muab tshuaj ntxiv rau kev luam ntawv, uas yog, cov kev siv digital uas siv los tiv thaiv cov teeb meem luam tawm raws li half-hour technology.
Tsis tas li ntawd, piv nrog cov ntawv xov xwm hauv digital xov xwm, cov xov xwm digital waving thov kom tiv thaiv cov ntawv luam tawm cov khoom siv raws li qee cov kev cai tshwj xeeb ntxiv nrog rau cov kev cai hauv qab no:
1 qhov muag pom thiab lub tshuab nyeem tau. Thaum siv cov khoom siv luam ntawv los yog luam ntawv, tus tub ntxhais kawm ntxiv ntawm ntau yam kev txiav txim yuav tsis tuaj yeem pom tshwm sim vim qhov kev daws teeb meem. Nyob rau tib lub sijhawm, nws tsis cuam tshuam rau qhov zoo ntawm daim ntawv luam thawj cov ntaub ntawv tshwj xeeb los ntawm kev sib tw khoom thiab computer software. Qhia txog.
2 kuj muaj xim hloov dua siab tshiab, hom ntaub ntawv hloov Los ntawm txoj haujlwm A / D thiab D / A, cov txheej txheem digital watermark yuav tsum tswj kom tsis txhob muaj kev sib thooj gamma thiab xim distortion. Ntxiv mus, nyob rau hauv cov txheej txheem ntawm cov duab duab, xim distortion tseem yuav tshwm sim vim cov laus ntawm cov teeb meem luam tawm. Nyob rau tib lub sijhawm, nws yuav tsum muaj peev xwm tiv tau qhov kev hloov dua siab tshiab thiab kev ua haujlwm (kev sib hloov, kev ywj pheej, kev sib tsoo, thiab lwm yam) ntawm cov ntaub ntawv tawm suab (xws li BMP, TIFF, JPEG, thiab lwm yam).
3 Yuav tsis muaj kev tshwj xeeb rau cov khoom siv luam ntawv, tsis muaj kev hloov hauv kev luam ntawv, thiab tsis nce nqi luam ntawv.
2, txoj cai thiab algorithm
Lub hauv paus ntawm digital watermarking technology rau kev luam tawm anti-counterfeiting yog yeej tib yam li cov xov tooj cua ntawm digital rau ntau hom, tshwj tsis yog tias nyob hauv txoj kev ntim ntawm kev ua dej num, kev ntsuam xyuas yuav tsum raug xam tias yog, thiab nyob rau hauv tus txheej txheem ntawm extracting thiab ntes cov ntawv pov thawj, cov ntaub ntawv ntawm cov ntaub ntawv luam tawm yuav tsum tau nqa tawm. Kev xaav, muaj ib qho kev hloov ntawm analog / digital (A / D) hauv txoj haujlwm no. Qhov no yuav tsum tau hais tias algorithms raws li half-half cov kev ua haujlwm cov kev ua haujlwm qub yuav tsum yog qhov tseem ceeb ntawm cov khoom ntaws thiab kev kuaj pom.