I-Chrominance: Iyini Ekukhiqizweni Kwevidiyo?

ngo kim Kubuyekezwe: June 27, 2022

I-Chrominance ingenye yezici ezibaluleke kakhulu ze ividiyo ukukhiqizwa. Kunomthelela omkhulu ekutheni okubonwayo kuvela kanjani kuvidiyo futhi kungasetshenziswa thuthukisa ikhwalithi yezithombe zevidiyo.

I-Chrominance ibhekisela ku- umbala, ukugcwala, nokuqina we imibala kuvidiyo.

Kulesi sihloko, sizoxoxa nge-chrominance kabanzi futhi sibheke indima yayo ekukhiqizweni kwevidiyo.

Incazelo ye-Chrominance

I-Chrominance (eyaziwa nangokuthi umbala) iyingxenye yokukhiqizwa kwevidiyo edlulisa umbala nokugcwala kwesithombe. Ingenye yezingxenye ezimbili zesignali yevidiyo, enye ibe yayo ukukhanyisela (ukukhanya). I-Chrominance imelwe izixhumanisi zemibala emibili - Cb kanye no-Cr - okuhlanganisa ukumelela iphalethi yombala eyingqayizivele uma kuqhathaniswa nokuxhumanisa kwayo kokukhanya okungu-Y.

I-Chrominance iqukethe ulwazi mayelana ne- izinga, umthunzi, tint nokujula kwemibala kusignali yevidiyo. Isibonelo, i-chrominance ingasetshenziswa ukuhlukanisa amathoni esikhumba kweminye imibala esithombeni ngokukhomba amaphikseli anamanani athile ombala. Ngokufanayo, i-chrominance ingasetshenziswa ukuthuthukisa imininingwane efana ukuthungwa noma ukuhluka okuncane ekukhanyeni, e digital amafomethi wevidiyo, i-chrominance igcinwa ngokuhlukile kumanani okukhanya, okuvumela ukuminyanisa okuphumelelayo kwedatha ngaphandle kokwehliswa kwekhwalithi yesithombe.

Umlando weChrominance

I-Chrominance, noma I-Chroma, ingenye yezingxenye ezimbili zombala ezisetshenziswa ekukhiqizweni kwevidiyo (kanye nokukhanya). Ibalwa ngokulinganisa ubukhulu bokukhanya ngemibala ethile - ngokuvamile obomvu, oluhlaza okotshani noluhlaza okwesibhakabhaka. Lapho umbala othile ukhanya kakhulu, iba ne-chroma eyengeziwe.

Isikhathi 'chrominance' yaqalwa uWalter R. Gurney ngo-1937 futhi ayizange ishintshe kusukela ngaleso sikhathi. Kusukela lapho, iye yasetshenziswa kakhulu ekukhiqizweni kwethelevishini njengoba imibala yayo emithathu eyinhloko (obomvu, oluhlaza okotshani noluhlaza okwesibhakabhaka) ifana kakhulu naleyo yamashubhu ombala kamabonakude kusukela yasungulwa. Nakuba amathelevishini anamuhla engasewona amashubhu e-cathode-ray asekelwe emininingwaneni ye-chroma ne-luma, amakhamera amaningi esimanje ayaqhubeka esebenzisa lezi zingxenye ukuze aqophe izithombe ezinemibala.

I-Chrominance ivumela ukurekhodwa okunembe kakhudlwana kombala kunalokho okwakutholakala kufilimu ye-monochrome (emnyama nokumhlophe) ngaphambi kokuthuthukiswa kwamasistimu evidiyo ayinhlanganisela ngo-1931. I-Chrominance ivamise ukukalwa kusetshenziswa i-oscilloscope noma imonitha ye-waveform ekhomba izinguquko ezicashile kumazinga ombala kuzo zonke izingxenye. sesithombe sevidiyo - ngisho nalezo ezingabonakali ngeso lenyama - ukuqinisekisa ukuthi imibala ihlala ingaguquki phakathi kwamakhamera namadivayisi phakathi nezinqubo zangemuva kokukhiqiza ezifana nokuhlela kanye nombhalo wekhodi wamafomethi okusabalalisa edijithali afana nezinsizakalo zokusakaza ze-inthanethi noma imidiya ye-disc efana Blu-Ray discs noma DVD.

Izingxenye zeChrominance

I-Chrominance ulwazi lombala osesithombeni noma kuvidiyo olusiza ukudala umuzwa wemvelo. I-Chrominance ihlanganisa izingxenye ezimbili: hawu futhi ukugcwala.

• Hue umbala wangempela wesithombe.
• Gcwalisa inani lombala omsulwa okhona esithombeni.

Zombili ziyizici ezibalulekile zokukhiqizwa kwevidiyo futhi kuzoxoxwa ngemininingwane eyengeziwe ngezansi.

Hue

Hue ingenye yezingxenye ezakha i-chrominance. Igama elisetshenziswa ekukhiqizweni kwevidiyo ukumela indawo yombala ku-spectrum kusuka obomvu ukuya kokuluhlaza kuya kokuluhlaza okwesibhakabhaka. I-hue inquma ukuthi yimuphi umbala okhona nokuthi ubonakala ugcwele kangakanani esithombeni. I-Hue ingamelwa njengenombolo phakathi 0 no-360 degrees, okuthi 0 kubebomvu, 120 kube luhlaza, futhi 240 kube luhlaza okwesibhakabhaka. Idigri ngayinye ihlukaniswe ngama-increments ka-10, ngamavelu e-hexadecimal njengokuthi 3FF36F emele imibala ethile.

Ngokungeziwe encazelweni yemibala ye-monochrome yamashaneli amathathu, amanye amasistimu ezithombe asebenzisa izincazelo zemibala yeziteshi ezine noma ezinhlanu ukuze uthole izincazelo ezinembe kakhudlwana zokuhlukahluka kombala.

Gcwalisa

Gcwalisa, ngezinye izikhathi kuthiwa i-chroma or chrominance, iyingxenye yombala ekukhiqizweni kwevidiyo. Ukugcwaliswa kwesikhala kukala inani lokumpunga embala. Isibonelo, umbala oluhlaza okotshani unokugcwala okuningi kunombala ompunga-oluhlaza; okuluhlaza okufanayo kungaba nokugcwaliswa kwezikhala okuhlukene kuye ngokuthi kubonakala kukhanye kangakanani. Uma ukugcwala kwesithombe kunyuswa, umbala waso nokucwebezela kuba namandla kakhulu; lapho incipha, umbala nokucwebezela kuyancipha.

Isikali esichaza izinga lokugcwaliswa kwesikhala esithombeni saziwa ngokuthi amazinga chrominance; lokhu kubhekisela kumathoni avela kumnyama (akukho chrominance) ukuya emabaleni agcwele ngokugcwele ngokuqina kwawo okuphezulu. Ngokulungisa lawa maleveli uyakwazi ukwenza ukulungisa kombala noma umane uthuthukise imibala ngaphakathi kwesithombe sakho ngokuqinisa amathoni athile noma ngokudala umehluko obanzi phakathi kwemibala emnyama nekhanyayo. Lokhu kungasetshenziswa emhlabeni wonke kuyo yonke imibala esesithombeni sakho, noma kuhlelwe phansi futhi kulungiswe amashaneli athile ombala ahlanganisa noma iyiphi indawo ethintekile yohlaka (njenge obomvu noma oluhlaza okwesibhakabhaka).

iLuminance

Ukukhanya kuyisici esibalulekile se-chrominance futhi kuhlotshaniswa nombono wokukhanya. Kunoma yisiphi isikhala sombala esinikeziwe, ukukhanya kuyisilinganiso esizimele sokuthi kanjani kukhanya noma buthuntu umbala othile ubonakala unjalo. Izinga lokukhanya lingathinta indlela okuqukethwe okuvela ngayo ngokuya ngokugqama, ukugcwaliswa kwesikhala, namazinga ombala.

Ekukhiqizweni kwevidiyo, ukukhanya kudlala indima ebalulekile ekunqumeni i- ukukhanya kwesithombe. Isibonelo, uma isithombe sinamazinga aphezulu kakhulu okukhanya, sizovela sigezekile futhi sifiphele, kuyilapho isithombe esinokukhanya okuphansi sizovela simnyama futhi sinodaka. Ngakho-ke, abakhiqizi bevidiyo kufanele balungise amazinga okukhanya ukuze bathole umphumela ofunekayo wesigcawu ngasinye.

Iningi lezinhlelo zokusebenza zevidiyo zihlanganisa i-a “Luma curve” okuvumela ochwepheshe bevidiyo ukuthi benze izinguquko ezicashile ukuze bahlele kahle izithombe zamadivayisi aphumayo njengezikrini zikamabonakude noma amaphrojektha edijithali anezici ezihlukile zokuhumusha ulwazi lombala. Amajika e-Luma ahlanganisa amaphuzu ayishumi nesithupha amelela izinyathelo ezingu-16 ezihlukaniswa ngokulinganayo esikalini esimnyama esikhanyayo (kusuka ku-0-3) phakathi kwebanga elithile elimelela uziro omnyama kwesokunxele nomhlophe ohlangothini lwesokudla okubonisa ithoni ephelele elungile kuzo zonke izithombe ngaphakathi kokulandelana kwawo wonke noma uhlelo. .

Izinhlobo zeChrominance

I-Chrominance igama elisetshenziswa ekukhiqizweni kwevidiyo ukuchaza umehluko phakathi kokukhanya kanye ne-chromaticity. Isetshenziselwa ukukala ukugcwaliswa kwesikhala kwemibala kuvidiyo, futhi ingasetshenziswa ukuthola izinguquko ekukhanyeni nasembalani.

Kunezinhlobo ezimbili zeChrominance: ukukhanyisela futhi chrominance. Uhlobo ngalunye lunezici zalo ezihlukile kanye nezinzuzo zokukhiqizwa kwevidiyo. Sizohlola zombili izinhlobo kulesi sihloko.

RGB

RGB (obomvu, oluhlaza, oluhlaza okwesibhakabhaka) imodeli yombala esetshenziswa kakhulu ekukhiqizweni nasekuklanyweni kwevidiyo yedijithali lapho kuhlanganiswa imibala eyinhloko yesithombe noma ividiyo. I-RGB idala ukukhanya okumhlophe okuvela emithonjeni yokukhanya emithathu enemibala ehlanganiswa ukuze kwakhe i-beam eyodwa. Lesi simiso semibala sidala imibala enjengokuphila ngokubonisa inani eliphakeme lemibala ndawonye ukuze silingise ngokuseduze ngangokunokwenzeka lokho okungabonwa ngeso lomuntu.

Umthombo uhlelwa kusetshenziswa isishumeki seziteshi ezintathu sokulinganisela phakathi kokugcwaliswa kwesikhala nokukhanya, okuvumela umbala ngamunye oyinhloko (okubomvu, okuluhlaza okwesibhakabhaka nokuluhlaza) ukulawulwa ngokuzimela ngaphandle kwabanye. Inzuzo enkulu yale modeli ukusebenza kwayo okuvelele ngokwemibandela ye ukukhanya nokunemba uma kuziwa ekukhiqizeni imibala egqamile.

I-YUV

I-YUV, eyaziwa nangokuthi yi-YCbCr, iwukukhanya (Y) kanye nezingxenye ezimbili ze-chrominance (U futhi V). Izingxenye ze-chrominance zesikhala sombala wedijithali zibonisa ukuthi isignali inemibala kangakanani. I-YUV, evame ukusetshenziswa ekuthwebuleni izithombe zedijithali nokuqoshwa kwevidiyo, iyinhlanganisela yokukhanya kanye namanani amabili e-chrominance amelela amasiginali omehluko wokubomvu nokuluhlaza okwesibhakabhaka. Lolu hlelo luvumela izidingo ezincishisiwe zomkhawulokudonsa uma kuqhathaniswa nokucubungula isignali ye-RGB yendabuko ekukhiqizweni kwevidiyo.

Kumodeli ye-YUV, isignali ebomvu imelelwa njenge "NOMA" kuyilapho isignali eluhlaza okwesibhakabhaka imelelwa njenge "V", kanye nokukhanya (Y). Amasiginali we-U no-V asuswa ekukhanyeni okuphelele ukuze amele imininingwane emibalabala esithombeni. Ukuhlanganisa lawa manani amathathu kusinikeza impumuzo kumfuneko yomkhawulokudonsa kuyilapho sigcina ikhwalithi ingaguquki phakathi nenqubo yokufaka ikhodi/yokusakaza ividiyo.

Ifomethi yombala ye-YUV isekelwa ngokomdabu amakhamera evidiyo amaningi abathengi kanye namafayela esithombe se-JPG athathwe omakhalekhukhwini abavame ukuthwebula izithombe kusetshenziswa ifomethi ye-YUV ngaphambi kokuzicindezela zibe ama-JPEG. Ngokuqhubekayo, lapho usakaza noma ufaka ikhodi lezi zithombe kusiza kakhulu njengoba idatha encane idinga ukudluliselwa ngenxa yokuba ngcono kwayo. izinga lokuya kumkhawulokudonsa impahla. Ngenxa yalezi zici kukhethwa kune-RGB ngezinjongo zokusakaza lapho ukulahlekelwa kwekhwalithi encane kungalindelwa ngenxa yayo imfuneko yomkhawulokudonsa ophansi lapho kwamukelwa izinqubo zokufaka ikhodi/ukusakaza bukhoma.

YIQ

YIQ wuhlobo lwe-chrominance oluvame ukusetshenziswa namafomethi wevidiyo ye-analog ye-NTSC endala. Ingxenye ye-Y ithwebula ukukhanya kwesithombe, kuyilapho izingxenye ze-I ne-Q zithwebula umbala noma i-chrominance. Isebenza ngokuhlukanisa umbala onikeziwe ezingxenyeni zayo ze-xy axis, eyaziwa ngokuthi i-Hue (H) yayo kanye Nokugcwaliswa kwesikhala (S). Amanani e-YIQ abe esesetshenziselwa ukwakha i-matrix ye-RGB evumela ukukhiqizwa kombala okunembe kakhudlwana kumasistimu ahlukene.

YIQ empeleni ithatha isignali ye-RGB futhi iyihlukanise izingxenye ezintathu:

• Y (Ukukhanya)
• I (umbala osesigabeni)
• Q (umbala we-quadrature)

Umehluko phakathi kwengxenye yesigaba nequadrature ucashile, kodwa empeleni ngithwebula ipheya eyodwa yemibala eyinhloko, kuyilapho u-Q ethwebula ipheya yesibili. Ngokuhlangene lezi ziteshi ezintathu ziyakwazi ukudala ukuhlukahluka okubonakala kungapheli kumbala, ukugcwala, nokukhanya okuvumela ababukeli ukuthi baphinde bazenzele ngokwabo ukuzibuka kwabo.

YCbCr

I-YCbCr (evame ukubizwa ngokuthi yi-Y'CbCr) wuhlobo lwe-chrominance olwakhiwe iziteshi ezintathu. Lezi ziteshi ziyi iluma (Y), i-chroma yomehluko oluhlaza okwesibhakabhaka (Cb) futhi i-chroma yomehluko obomvu (Cr). I-YCbCr isekelwe enguqulweni ye-analog ebizwa ngokuthi i-YPbPr, iyenza ifane ngandlela thize nesikhala sombala se-RGB. Nakuba i-YCbCr ivame ukusetshenziswa kakhulu ekukhiqizweni kwevidiyo, izithombe zedijithali zingabhalwa ngefomethi efanayo.

Umqondo ongemuva kwe-YCbCr ukuthi yehlisa inani ledatha elidingekayo ukumela isithombe sombala. Ngokuhlukanisa ulwazi olungakhanyisi lube ezinye iziteshi ezimbili, inani eliphelele ledatha yesithombe sonke lingancishiswa kakhulu. Lokhu kuvumela ividiyo yekhwalithi ephezulu noma izithombe zedijithali ezinosayizi bamafayela amancane, okwenza kube lula ukuwagcina nokudlulisa.

Ukuze kuzuzwe lokhu kwehliswa kosayizi wedatha, amazinga ahlukene okunemba asetshenziswa phakathi kwesiteshi ngasinye. I-luma ingaba nokulungiswa kwamabhithi angu-8 kanye ne-chrominance 4 noma 5 bits. Kuye ngokuthi yiluphi uhlobo lwesisetshenziswa osisebenzisayo kunamaleveli amaningana atholakalayo, okuhlanganisa:

• 4:4:4 futhi 4:2:2 (amabhithi ama-4 esiteshini ngasinye),
• 4:2:0 (amabhithi ama-4 e-luma, ama-2 ngokuluhlaza okwesibhakabhaka no-2 ngokubomvu).

Izinhlelo zokusebenza zeChrominance

I-Chrominance, uma isetshenziswa ekukhiqizweni kwevidiyo, isho ukusetshenziswa kwe faka umbala kuvidiyo. I-Chrominance iyithuluzi elibalulekile lokudala okubonakalayo okuvezayo nokucacile, okuvumela abaqondisi ukuthi bathuthukise imizwa nemizwelo yesigcawu.

Lesi sihloko sizohlola izindlela ezahlukahlukene i-chrominance engasetshenziswa ngayo ekukhiqizweni kwevidiyo, okuhlanganisa nokusetshenziswa kwe:

• Ukugreda kombala
• Ukufaka umbala
• Amaphalethi ombala

Ukufakwa Kombala

Enye yezinhlelo zokusebenza ezibaluleke kakhulu ze-chrominance ekukhiqizweni kwevidiyo ukufaka umbala. Ukuhlelwa kombala kuyindlela yokuthuthukisa isithombe sevidiyo. Njengoba igama lisho, isebenzisa amasu ahlukahlukene ukulungisa ama-hues, ama-saturations kanye nezinye izimfanelo zokwenza ishothi igqame noma ihlangane nendawo ekuzungezile. Amazinga e-Chrominance zibaluleke kakhulu kule nqubo, njengoba zingasetshenziswa ukudala isimo sengqondo noma ithoni ethile.

Isibonelo, uma isigcawu sisethwe ngasogwini lolwandle ngokuntwela kokusa futhi sidinga ukuba nomuzwa we-ethereal, amaleveli e-chrominance angalungiswa ngokufanele ukuze kuthuthukiswe ukukhanya kwelanga okufudumele futhi kwengeze ama-shades acashile oluhlaza okwesibhakabhaka ukuze kube nokuzwakala okunomoya. Ngokufanayo, uma isigcawu sidinga umuzwa owengeziwe noma idrama, amaleveli okugcwaliswa kwesikhala angakhushulwa kuyilapho kugcinwa ubuqotho bekhwalithi yesithombe soqobo ngokulungisa ngezilawuli ze-chrominance.

Ukuhlelwa kombala kusiza ukuqinisekisa ukuthi wonke amashothi ngaphakathi kwephrojekthi ethile avela afanayo ngokuya ngamathoni nomuzwa ukuze ukuhlela nokukhiqizwa kwangemuva kuhambe kahle.

Ukucindezelwa kwevidiyo

Ukucindezelwa kwevidiyo kuyinqubo yokukhipha ulwazi kusignali yevidiyo ukuze kwehliswe usayizi wefayela noma umkhawulokudonsa wokudlulisela. Lokhu kubandakanya ukunciphisa imininingwane kanye/noma ukulungiswa kwanoma iyiphi ividiyo enikeziwe. I-Chrominance kubaluleke kakhulu kule nqubo njengoba inquma izici zombala ngaphakathi kwesignali yevidiyo.

Ngokunciphisa i-chrominance, ukuminyanisa kwevidiyo kungenza izinzuzo ezinkulu ngokonga idatha kanye nokudlulisa ukusakaza, kube nomthelela omncane kwikhwalithi. I-Chrominance ingasetshenziswa ezinhlotsheni eziningi ezahlukene zemidiya, njengokusakazwa kukamabonakude, amavidiyo asakazwayo namadiski e-Blu-ray.

Njengoba i-chrominance iphethe ulwazi olubalulekile olubonakalayo esilubiza ngombala, ukuyifaka ngekhodi kancane kodwa ngokuphumelelayo kusivumela ukuthi sicindezele amavidiyo ngaphandle kokudela ukunemba kombala noma ukugcwaliswa kwesikhala - izici ezimbili ezibalulekile ekudaleni okubonwayo okungokoqobo. I-Chrominance ithinta ukuthi ingakanani idatha edingekayo ukuze kugcinwe futhi/noma kudluliselwe okuqukethwe komsindo nokubukwayo; ngokuyisebenzisa ngokugcwele, sibonisa ukuhlala sincane ngenkathi sigcina a izinga eliphezulu lekhwalithi emibonweni yethu.

Ukulungiswa kombala

Isignali ye-chrominance ingenye echaza inani lombala esithombeni, kunokukhanya. Ekukhiqizweni kwevidiyo nasekucutshungulweni kwangemuva, ukunquma ibhalansi ephumelelayo ye-chrominance kuhlanganisa ukusebenzisa isofthiwe ukulungisa izinga lokushisa lombala wesithombe noma ividiyo. Lena inqubo eyaziwa ngokuthi ukulungiswa kombala.

Ukulungiswa kombala ekukhiqizweni kwangemuva kwevidiyo kuvame ukubhekisa kunoma yikuphi ukuguqulwa kwezithombe ezikhona njengokuthi ukwandisa noma ukunciphisa ukugcwala kwesikhala, ukulungisa ibhalansi emhlophe, kanye nokushintsha izici ezithile zokugqama. Lokhu kulungiswa kungashintsha ukubukeka kwevidiyo ngokuphawulekayo ngokushintsha indlela izingxenye ezikhanyayo nezimnyama ezinikezwa ngayo, indlela imibala exutshwe ngayo enye kwenye, ukushuba kwemibala ehlukahlukene kuyo yonke imifanekiso, nokuningi.

Ngamafuphi, ukulungiswa ku-chrominance kusebenza njengethuluzi lokunikeza noma yisiphi isigcawu ithoni nesimo esinqunywe kusengaphambili. Ukulungiswa kombala ngokuvamile kwenzeka uma kunemibala engalungile noma engahambisani esithombeni okungaholela ekudidekeni lapho uzama ukuhumusha incazelo noma injongo yaso. Isibonelo, uma ukukhanya kusethi kungahambisani kahle ukusuka esigcawini kuye kwesinye, lokhu kungaholela kumehluko wemibala phakathi kwamashothi amabili athathwe amaminithi ahlukene ukusuka kwenye. Ngokulungiswa kwe-chrominance lokhu kudideka kungadanjiswa ngokubuyisela yonke into ekuvumelaneni nayo uqobo - ikakhulukazi mayelana nemibala yayo - ngakho-ke ibonakala ikhanya kahle futhi ihambisana nalokho okwakucatshangwa ekuqaleni njengengxenye yethagethi yobuhle besiqephu.

Isiphetho

Ukufingqa, i-chrominance isici sombala esingashintshwa futhi sisetshenziswe lapho kukhiqizwa ividiyo. Chrominance, noma i-chroma ngamafuphi, kunqunywa ngokulinganisa umbala nokugcwala yombala ukuyinikeza ukubukeka kwayo okuyingqayizivele. Ukukhohlisa i-chrominance iyithuluzi elinamandla labenzi bamafilimu, njengoba bengayisebenzisela ukudala izigcawu ze-surreal nezinhle ngamasu okukhanyisa anekhono.

Ngokuqonda izisekelo ze-chrominance, abenzi bamafilimu bangakwazi ukulawula ubuciko obungaphezulu kwesimo samaphrojekthi abo.

Sawubona, nginguKim, umama kanye nomshisekeli we-stop-motion onesizinda ekudalweni kwemidiya nokuthuthukiswa kwewebhu. Nginothando olukhulu lokudweba nokugqwayiza, futhi manje sengingena ngekhanda emhlabeni onyakazayo. Ngebhulogi yami, ngabelana ngezifundo zami nani bafana.