22/04/22Rima Signal Non-Uniformity (DSNU) chiyero chemwero wenguva-yakazvimirira shanduko kumashure kwemufananidzo wekamera. Inopa hutsinye hwenhamba inoratidza kunaka kweiyo mufananidzo wekumashure, maererano nemapateni kana zvimiro zvinogona kuvepo dzimwe nguva.
Mumifananidzo yakaderera-mwenje, kunaka kwekamera kunogona kuve chinhu chakakosha. Kana pasina mafotoni ari kuitika pakamera, mifananidzo yakawanikwa haiwanzo ratidza mapixel values e0 grey level (ADU). Kukosha kwe 'offset' kunowanzo kuvepo, senge 100 grey level, iyo kamera inozoratidza kana pasina chiedza, uye kana kubvisa kukanganiswa kweruzha pachiyero. Nekudaro, pasina kungwarira kugadzirisa uye kururamisa, panogona kunge paine imwe mutsauko kubva pixel kuenda pixel mune iyi yakatarwa offset kukosha. Musiyano uyu unonzi 'Fixed Pattern Noise'. DNSU inomiririra huwandu hweiyi yakagadziriswa patani ruzha. Inomiririra kutsauka kwakajairwa kwepixel offset values, kuyerwa mumaerekitironi.
Kune akawanda akadzika-mwenje ekufungidzira makamera, DSNU inowanzo pazasi kutenderedza 0.5e-. Izvi zvinoreva kuti yepakati- kana yepamusoro-mwenje maapplication ane mazana kana zviuru zvemafotoni akatorwa papixel, iyi ruzha rupiro haruna basa zvachose. Chokwadi, kune yakaderera mwenje maapplication zvakare, kupa iyo DSNU yakadzikira pane kamera kuverenga ruzha (kazhinji 1-3e-), iyi yakagadziriswa ruzha ruzha haigone kuita basa mumhando yemufananidzo.
Nekudaro, DSNU haisi inomiririra yakakwana yeyakagadziriswa patani ruzha, sezvo ichitadza kubata zvinhu zviviri zvakakosha. Chekutanga, makamera eCMOS anogona kuratidza mapatani akarongwa mune iyi mutsauko wekubvisa, kazhinji muchimiro chemakoramu emapikseli akasiyana kubva kune imwe neimwe mukukosheswa kwawo. Iyi 'Fixed Pateni Column Noise' ruzha runonyanya kuoneka kuziso redu kupfuura ruzha rusina kurongeka, asi musiyano uyu haumiririrwe neukoshi hweDSNU. Aya maartefacts anogona kuoneka kumashure kwemifananidzo yakadzikira, senge kana chiratidzo chepamusoro chaonekwa chiri pasi pe100 photo-electrons. Kuona 'kurerekera' mufananidzo, mufananidzo unoburitswa nekamera usina mwenje, uchakubvumidza kuti utarise kuvepo kweyakarongeka ruzha ruzha.
Chechipiri, mune dzimwe nguva, misiyano yakarongeka mukubvisa inogona kutsamira nguva, ichisiyana kubva kune imwe furemu kuenda kune inotevera. Sezvo DSNU ichiratidza chete shanduko-yakasununguka-nguva, izvi hazvina kubatanidzwa. Kuona kutevedzana kwemifananidzo yakarerekera kunokubvumira kuti utarise kuvepo kwehupo hwenguva-inotsamira yakarongeka ruzha ruzha.
Sezvacherechedzwa zvakadaro, DSNU uye kusiyanisa kwemashure kusiyanisa hakuzove chinhu chakakosha kune yepakati-kusvika-yepamusoro-mwenje maapplication ane zviuru zvemafotoni papixel, sezvo aya masaini achave akasimba zvakanyanya kupfuura kusiyana.
