25/08/19Uma kuziwa ekuthwebuleni izithombe ezinembayo nezithembekile ocwaningweni lwesayensi, ikhwalithi yedatha yakho incike kokungaphezu nje kokulungiswa noma usayizi wenzwa. Enye yezinto ezibaluleke kakhulu—kodwa ngezinye izikhathi ezinganakwa—i-Signal-to-Noise Ratio (SNR). Kumasistimu ezithombe, i-SNR inquma ukuthi ungahlukanisa ngokucace kangakanani isignali yangempela (ulwazi oluwusizo) nomsindo ongafuneki.
Kuzinhlelo zokusebenza zokuthwebula zesayensi ezifana ne-microscopy, i-astronomy, ne-spectroscopy, i-SNR engeyinhle ingasho umehluko phakathi kokuthola ithagethi ebuthakathaka nokugeja ngokuphelele. Lesi sihloko sihlola ukuthi i-SNR ichazwa kanjani, kungani ibalulekile, ukuthi ikuthinta kanjani ukugqama, nokuthi ungakhetha futhi ulungiselele kanjani ikhamera yesayensi ngokusekelwe kule metric ebucayi.
Iyini i-Signal-to-Noise Ratio futhi Ichazwa Kanjani?
I-Signal to Noise Ratio (SNR) isilinganiso esibaluleke kakhulu sekhwalithi yesithombe sethu, esibalulekile ekuhlukeni kwesithombe, futhi ngokuvamile iyisici esinqumayo esiwusizo kakhulu sokuthi ikhamera izwela ngokwanele yini ohlelweni lwakho lokusebenza.
Imizamo yokuthuthukisa ukuzwela kwekhamera izungeza kukho kokubili ukuthuthukisa isignali eqoqiwe:
● Ngokuthuthuka ekusebenzeni kahle kwe-quantum noma ukwanda kosayizi wamaphikseli
● Ukunciphisa imithombo yomsindo encike kukhamera
Imithombo yomsindo ihlangana ndawonye, kodwa kuye ngezimo umuntu angabusa, futhi kufanele kugxilwe kuzo lapho ezama ukuthuthukisa i-SNR - kungaba ngokulungiselela izilungiselelo noma ukusetha, noma ukuthuthukela emithonjeni yokukhanya engcono, okokubona, namakhamera.
Kuwukushusha okuvamile ukuchaza izithombe ngokwesilinganiso esisodwa sesignali-kuya-nomsindo, isibonelo ukufuna isithombe sine-SNR engu-'15'. Kodwa-ke, njengoba kubonakala egameni, isilinganiso sesignali-kuya-kumsindo sincike kusignali, okuzohluka ngephikseli ngayinye. Yilokhu okusinika isithombe sethu.
I-SNR yesithombe ngokuvamile ibhekisela ku-SNR yesiginali ephezulu yentshisekelo ngaphakathi kwesithombe. Isibonelo, i-SNR esuka esithombeni samaseli e-fluorescent kungemuva elimnyama izosebenzisa ukuqina kwesiginali ephezulu ukusuka kumaphikseli wesakhiwo sentshisekelo ngaphakathi kweseli.
Akumele ukuthatha, isibonelo, inani elimaphakathi le-SNR yaso sonke isithombe. Kumasu afana ne-fluorescence microscopy lapho ingemuva elimnyama elinama-photons atholwe uziro lingavama, lawa maphikseli esignali anguziro ane-SNR enguziro. Ngakho-ke, noma yisiphi isilinganiso esithombeni kuzoncika ekutheni mangaki amaphikseli angemuva abebukwa.
Kungani I-SNR Ibalulekile Ngamakhamera Wesayensi
Emfanekisweni wesayensi, i-SNR ithinta ngokuqondile indlela ongabona ngayo imininingwane ebuthakathaka, ulinganise idatha yobuningi, uphinde ukhiqize imiphumela.
●Ukucaca Kwesithombe- I-SNR ephezulu inciphisa ubuhlalu futhi yenza izakhiwo ezinhle zibonakale.
●Ukunemba Kwedatha- Yehlisa amaphutha okulinganisa ekuhloleni okusekelwe ukuqina.
●Ukusebenza Kokukhanya Okuphansi- Ibalulekile ku-fluorescence microscopy, i-deep-sky astrophotography, kanye ne-spectroscopy, lapho izibalo ze-photon ziphansi ngokwemvelo.
Ukuthi usebenzisa i-aIkhamera ye-sCMOSngesithombe esinesivinini esikhulu noma i-CCD epholile yezinhlelo zokusebenza zokuchayeka isikhathi eside, ukuqonda i-SNR kukusiza ukuthi ulinganisele ukuhwebelana kokusebenza.
I-SNR Ikuthonya Kanjani Ukugqama Kwesithombe
Ukugqama umehluko ohlobene ngokuqina phakathi kwezindawo ezikhanyayo nezindawo ezimnyama zesithombe. Kuzinhlelo zokusebenza eziningi, ukugqama okuhle kwesithombe phakathi kwezindawo onentshisekelo kuzo kuwumgomo wokugcina.
Kunezici eziningi ngaphakathi kwesihloko sokuthwebula, isistimu yokubona kanye nezimo zesithombe eziyizici ezinqumayo zokugqama kwesithombe, njengekhwalithi yelensi kanye nenani lokukhanya kwangemuva.
●Inani eliphakeme kakhulu lama-SNR→ Ukwehlukaniswa okuhlukile phakathi kwezifunda ezikhanyayo nezimnyama; imiphetho ibonakala icwebile; imininingwane ecashile ihlala ibonakala.
●I-SNR ephansi→ Izindawo ezimnyama ziya ngokuya zikhanya ngenxa yomsindo, izindawo ezikhanyayo ziba lufifi, futhi umehluko wesithombe usuwonke uyafiphala.
Isibonelo, ku-microscopy ye-fluorescence, i-SNR ephansi ingenza isampula ye-fluorescent ebuthakathaka ihlanganiswe ngemuva, okwenza ukuhlaziya kobuningi kungathembeki. Kusayensi yezinkanyezi, izinkanyezi ezifiphele noma imithala inganyamalala ngokuphelele kudatha enomsindo.
Kodwa-ke, kuphinde kube nezici ngaphakathi kwekhamera ngokwayo - into eyinhloko i-Signal to Noise Ratio. Ngokuqhubekayo, futhi ikakhulukazi ekukhanyeni okuphansi, ukukalwa kokuqina kwesithombe, indlela isithombe esivezwa ngayo kusiqapha, sidlala indima enkulu ekuhlukeni okucatshangwayo kwesithombe. Ngomsindo ophezulu ezindaweni ezimnyama zesithombe, ama-algorithms wokukala isithombe esizenzakalelayo angasethwa ngaphansi kakhulu ngamaphikseli anomsindo wenani eliphansi, kuyilapho isibopho esiphezulu sikhuphuka ngomsindo wamaphikseli esignali aphezulu. Lesi yimbangela yesici sokubukeka okumpunga 'okugeziwe' kwezithombe ze-SNR ephansi. Ukugqama okungcono kungatholwa ngokusetha isibopho esiphansi ku-offset yekhamera.
Izinto Ezithinta I-SNR Kumakhamera Wesayensi
Idizayini eminingana nemingcele yokusebenza ithonya i-SNR yohlelo lwekhamera:
Ubuchwepheshe benzwa
● I-sCMOS - Ihlanganisa umsindo ophansi wokufunda kanye namazinga aphezulu ozimele, alungele ukuthwebula isithombe esiguqukayo.
● I-CCD - Ngokomlando inikeza umsindo ophansi ekudaluleni okude, kodwa ihamba kancane kunemiklamo yesimanje ye-CMOS.
● I-EMCCD – Isebenzisa i-on-chip amplification ukuze ikhulise amasignali abuthakathaka, kodwa ingasethula umsindo ophindaphindayo.
Usayizi we-Pixel kanye ne-Fill Factor
Amaphikseli amakhulu aqoqa ama-photon amaningi, akhulisa isignali kanjalo ne-SNR.
I-Quantum Efficiency (QE)
I-QE ephezulu isho ukuthi ama-photon amaningi angenayo aguqulwa abe ama-electron, okwenza ngcono i-SNR.
Isikhathi sokuchayeka
Ukuchayeka okude kuqoqa ama-photon engeziwe, okwandisa isignali, kodwa kungase futhi kunyuse umsindo wamanje omnyama.
Amasistimu Okupholisa
Ukupholisa kunciphisa ubumnyama bamanje, kuthuthukisa kakhulu i-SNR ngokuchayeka isikhathi eside.
Optics kanye Illumination
Amalensi ekhwalithi ephezulu nokukhanya okuzinzile kukhulisa ukuthwebula kwesiginali futhi kunciphise ukuhlukahluka.
Izibonelo Zamanani Ahlukile E-Peak SNR
Emfanekisweni, i-PSNR ivamise ukusho umkhawulo wetiyori ohlobene nokugcwala kwephikseli. Naphezu komehluko ezihlokweni zokuthwebula izithombe, izimo zokuthwebula izithombe kanye nobuchwepheshe bekhamera, kumakhamera esayensi avamile, izithombe ezinesilinganiso esifanayo somsindo wesignali zingaba nokufana. Izinga 'lokuhlamvu', ukuhluka ukusuka kuhlaka kuya kohlaka, futhi ngokwezinga elithile ukugqama, kungase kufane kuzo zonke lezi zimo ezihlukene. Ngakho-ke, kungenzeka ukuzuza ukuqonda kwamanani e-SNR kanye nezimo nezinselele ezihlukahlukene ezisikiselayo kusukela kuzithombe ezimele, njengalezo eziboniswe kuthebula.
QAPHELA: Amanani esignali aphezulu kuma-photoelectrons kumugqa ngamunye anikezwe ngokuluhlaza okwesibhakabhaka. Zonke izithombe eziboniswa nge-auto histogram scaling, indiva (egcwele)0.35% wamaphikseli agqamile namnyama kakhulu. Amakholomu ezithombe ezimbili kwesokunxele: Isithombe esisekelwe kulensi sethagethi yokuhlolwa kwesithombe. Amakholomu amane kwesokudla: I-Ascaris ithwetshulwe nge-fluorescence ngenhloso yesibonakhulu esingu-10x. Ukubonisa ukuhluka kozimele kuhlaka ngamavelu ephikseli ku-SNR ephansi, ozimele abathathu abalandelanayo bayanikezwa.
Isithombe esisuselwe kwilensi sethagethi yokuhlola, kanye nesithombe se-fluorescence microscopy kokubili kuyaboniswa, kanye nokubuka okusondeziwe kwesithombe se-fluorescent okubonisa ukuhluka phakathi kwamafreyimu angu-3 alandelanayo. Inani eliphakeme kakhulu lama-electron esithombe ezingeni ngalinye lesiginali liyanikezwa.
Umfanekiso olandelayo ubonisa izinguqulo ezigcwele zalezi zithombe eziyisibonelo ukuze zisetshenziswe.
Izithombe ezinosayizi ogcwele ezisetshenziselwa ithebula lezibonelo zesilinganiso sesignali-kuya-nomsindo
Kwesokunxele: Ithagethi yokuhlolwa kwesithombe ethathwe ngelensi.
Kulungile: Isampula yesigaba se-Ascaris nematode worm esibukwe nge-fluorescence microscopy ekukhuliseni okungu-10x.
I-SNR kokuthi Izicelo
I-SNR ibalulekile emikhakheni ehlukahlukene:
● I-Microscopy - Ukuthola i-fluorescence efiphele kumasampuli ebhayoloji kudinga i-SNR ephezulu ukuze kugwenywe ama-negative angamanga.
● I-Astronomy - Ukukhomba imithala ekude noma ama-exoplanets kudinga ukuchayeka okude okunomsindo omncane.
● I-Spectroscopy - I-SNR ephezulu iqinisekisa izilinganiso zokuqina okuphezulu okunembile ekuhlaziyweni kwamakhemikhali.
● Ukuhlolwa Kwezimboni - Emigqeni yokuhlanganisa yokukhanya okuphansi, i-SNR ephezulu isiza ukuthola amaphutha ngendlela enokwethenjelwa.
Ukukhetha Ikhamera Yesayensi ene-SNR Elungile
Lapho uhlola ikhamera yesayensi entsha:
●Hlola Imininingwane ye-SNR- Qhathanisa amanani e-dB ngaphansi kwezimo ezifanayo nohlelo lwakho lokusebenza.
●Linganisa Amanye Amamethrikhi- Cabangela ukusebenza kahle kwe-quantum, ububanzi obuguqukayo, nezinga lozimele.
●Fanisa Ubuchwepheshe Bokusebenzisa Ikesi- Ezigcawini eziguqukayo ezinesivinini esikhulu, ikhamera ye-sCMOS ingase ibe ekahle; ngezihloko ezimile zokukhanya okuphansi kakhulu, i-CCD epholile noma i-EMCCD ingenza kangcono.
●Ukuxhumana Kokusebenza Kahle Kokusebenza– Nakuba zingathinti i-SNR ngokuqondile, izici ezifana nokuphumayo kwe-HDMI zinganika amandla ukubuyekezwa kwesithombe sesikhathi sangempela, zikusize uqinisekise ngokushesha ukuthi izilungiselelo zakho zokutholwa zifinyelela i-SNR oyifunayo.
Isiphetho
I-Signal-to-Noise Ratio (SNR) iyimethrikhi yokusebenza engukhiye ethonya ngokuqondile ukucaca nokuthembeka kwezithombe zesayensi. Ukuqonda ukuthi i-SNR ichazwa kanjani, izici eziyithintayo, kanye nemithelela yamanani ahlukene e-SNR kuvumela abacwaningi nabasebenzisi bezobuchwepheshe ukuthi bahlole amasistimu wokucabanga ngempumelelo kakhudlwana. Ngokusebenzisa lolu lwazi—kungakhathaliseki ukuthi ekukhetheni okushaikhamera yesayensinoma ulungiselela ukusetha okukhona—ungaqinisekisa ukuthi ukugeleza komsebenzi wakho wesithombe kuthatha idatha ngeleveli yokunemba okudingekayo kuhlelo lwakho lokusebenza oluthile.
Imibuzo Evame Ukubuzwa
Yini ebhekwa njenge-SNR "enhle" yamakhamera esayensi?
I-SNR ekahle incike kuhlelo lokusebenza. Ngomsebenzi onzima kakhulu, omningi—njenge-fluorescence microscopy noma i-astronomy—i-SNR engaphezu kuka-40 dB ngokuvamile iyanconywa, njengoba ikhiqiza izithombe ezinomsindo omncane obonakalayo futhi igcina imininingwane emihle. Ngokusetshenziswa kwelabhorethri okuvamile noma ukuhlolwa kwezimboni, 35–40 dB ingenela. Noma yini engaphansi kuka-30 dB ngokuvamile izobonisa okusanhlamvu okubonakalayo futhi ingafaka engcupheni ukunemba, ikakhulukazi ezimweni eziphansi zokugqama.
Ngabe ukusebenza kahle kwe-quantum (QE) kuyithinta kanjani i-SNR?
Ukusebenza kahle kwe-Quantum kulinganisa ukuthi inzwa iwaguqula kanjani ngempumelelo ama-photon angenayo abe ama-electron. I-QE ephakeme isho ukukhanya okwengeziwe okutholakalayo kuthwetshulwa njengesignali, kukhuphula inombolo ekubalweni kwe-SNR. Lokhu kubaluleke kakhulu ezimeni zokukhanya okuphansi, lapho i-photon ngayinye ibalulekile. Isibonelo, ikhamera ye-sCMOS ene-QE engu-80% izozuza i-SNR ephakeme ngaphansi kwezimo ezifanayo uma iqhathaniswa nenzwa eno-50% QE, ngenxa nje yokuthi ithwebula isignali esebenziseka kakhulu.
Uyini umehluko phakathi kwe-SNR ne-Contrast-to-Noise Ratio (CNR)?
Ngenkathi i-SNR ikala amandla esignali esewonke ngokuhlobene nomsindo, i-CNR igxila ekubonakaleni kwesici esithile ngokumelene nesizinda sayo. Emfanekisweni wesayensi, kokubili kubalulekile: I-SNR ikutshela ukuthi isithombe “sihlanzekile” kanjani sisonke, kuyilapho i-CNR inquma ukuthi into ethile ethakaselwayo igqama ngokwanele ukuze itholwe noma ikalwe.
Ufuna ukufunda okwengeziwe? Bheka izindatshana ezihlobene:
Ukusebenza Kwe-Quantum Kumakhamera Esayensi: Umhlahlandlela Wabaqalayo
I-Tucsen Photonics Co., Ltd. Wonke amalungelo agodliwe. Uma ucaphuna, sicela wazise umthombo:www.tucsen.com
