25/09/11Ma nā ʻōnaehana ana - mai ke kamaʻilio uea a hiki i ke kiʻi kiʻi kiʻi - ʻo ka ratio signal-to-noise (SNR) kahi pae kumu o ka maikaʻi. Inā ʻoe e kālailai ana i nā kiʻi telescope, hoʻomaikaʻi i ka hoʻopaʻa leo microphone, a i ʻole pilikia i kahi loulou ueaʻole, haʻi ʻo SNR iā ʻoe i ka nui o ka ʻike pono e kū mai ana mai ka walaʻau hope ʻole.
Akā ʻaʻole maʻalahi ka helu pono ʻana iā SNR. Ma muli o ka ʻōnaehana, pono e noʻonoʻo ʻia nā mea ʻē aʻe e like me ka pōʻeleʻele, ka leo heluhelu, a i ʻole pixel binning. Ke alakaʻi nei kēia alakaʻi iā ʻoe ma o ke kumumanaʻo, nā kumu kumu, nā hewa maʻamau, nā noi, a me nā ala kūpono e hoʻomaikaʻi ai i ka SNR, e hōʻoiaʻiʻo ana hiki iā ʻoe ke hoʻohana pololei ia ma nā ʻano ākea ākea.
He aha ka Signal-to-Noise Ratio (SNR)?
Ma kona kumu, e ana ka ratio signal-to-noise i ka pilina ma waena o ka ikaika o ka hōʻailona i makemake ʻia a me ka walaʻau hope e pohihihi ana.
● Hōʻailona = ka ʻike koʻikoʻi (e laʻa, he leo i ke kelepona, he hōkū ma ke kiʻi telescope).
● Noise = nā loli like ʻole a makemake ʻole e hoʻopololei a hūnā paha i ka hōʻailona (e laʻa, static, kani kani, keakea uila).
Ma ka makemakika, ua wehewehe ʻia ka SNR penei:
No ka mea hiki ke ʻokoʻa kēia mau lakio ma luna o nā kauoha o ka nui, hōʻike pinepine ʻia ka SNR i nā decibels (dB):
● SNR kiʻekiʻe (e laʻa, 40 dB): ʻoi aku ka mana o ka hōʻailona, e hopena i ka ʻike maopopo a hilinaʻi.
● SNR haʻahaʻa (e laʻa, 5 dB): hoʻopau ka walaʻau i ka hōʻailona, e paʻakikī ai ka wehewehe ʻana.
Pehea e helu ai i ka SNR
Hiki ke helu ʻia ka lākiō hōʻailona-a-noise me nā pae ʻokoʻa o ka pololei ma muli o nā kumu leo i hoʻokomo ʻia. Ma kēia ʻāpana, e hoʻokomo ʻia nā ʻano ʻelua: ʻo kekahi e hōʻike ana i ka pōʻeleʻele a me kekahi e manaʻo nei hiki ke mālama ʻia.
Nānā: Pono ka hoʻohui ʻana i nā waiwai walaʻau kūʻokoʻa e hoʻohui iā lākou i ka quadrature. Hoʻopili ʻia kēlā me kēia kumu o ka walaʻau, hōʻuluʻulu ʻia, a lawe ʻia ke kumu huinahā o ka huina.
Lakiō hōʻailona me ka walaʻau me ke au ʻeleʻele
ʻO kēia ka hoohalike e hoʻohana ai i nā kūlana i lawa ka nui o ka walaʻau pōʻeleʻele e koi ai e hoʻokomo:
Eia ka wehewehe ʻana o nā huaʻōlelo:
Hōʻailona (e-): ʻO kēia ka hōʻailona o ka hoihoi i nā photoelectrons, me ka unuhi ʻana o ka hōʻailona ʻeleʻele
ʻO ka hōʻailona holoʻokoʻa (e-) ka helu kiʻi kiʻi i loko o ka pika o ka hoihoi - ʻaʻole loa ka waiwai pika i nā ʻāpana o nā pae hina. ʻO ka lua o ka hōʻailona (e-), ma lalo o ka hoohalike, ʻo ia ka walaʻau kiʻi kiʻi.
ʻĀnō ʻeleʻele (DC):ʻO ka waiwai pōʻeleʻele o kēia manawa no kēlā pika.
t: Ka manawa hōʻike i kekona
σr:E heluhelu i ka walaʻau ma ke ʻano pahupaʻikiʻi.
Lakiō hōʻailona-a-noise no ka ʻike ʻole o ka pōʻeleʻele
I nā hihia pōkole (< 1 kekona) nā manawa hōʻike, a me nā pahupaʻikiʻi hoʻomaha, hana kiʻekiʻe, ʻoi aku ka maikaʻi o ka walaʻau ʻeleʻele ma lalo o ka leo heluhelu, a mālama ʻole ʻia.
Ma kahi o nā huaʻōlelo e like me ka wehewehe ʻana ma luna, koe wale nō ʻaʻole pono e helu a unuhi ʻia ka hōʻailona o kēia manawa ʻeleʻele mai ka hōʻailona e like me ka zero.
ʻO nā palena o kēia mau ʻōlelo hoʻohālikelike a me nā huaʻōlelo i nalowale
E hāʻawi wale nā kumu hoʻohālikelike i nā pane pololei no CCD aNā kiʻi paʻi kiʻi CMOS. Hoʻokomo ʻo EMCCD a me nā mea hoʻoikaika ikaika i nā kumu walaʻau hou, no laila ʻaʻole hiki ke hoʻohana ʻia kēia mau hoohalike. No ka hōʻailona hōʻailona-a-noise ratio equation e pili ana i kēia a me nā haʻawina ʻē aʻe.
ʻO kekahi huaʻōlelo walaʻau ʻē aʻe (a i ʻole ma mua) i hoʻokomo pinepine ʻia i loko o nā hoʻohālikelike SNR ʻo ia ka pane kiʻi ʻole like ʻole (PRNU), a i kekahi manawa i kapa ʻia ʻo 'noise pattern paʻa' (FPN). Hōʻike kēia i ka like ʻole o ka loaʻa a me ka pane ʻana o ka hōʻailona ma waena o ka sensor, hiki ke lilo i mea nui ma nā hōʻailona kiʻekiʻe inā nui ka nui, e hōʻemi ana i ka SNR.
ʻOiai he nui ka PRNU o nā kāmela mua e koi ai i kona hoʻokomo ʻana, ʻo ka mea hou loanā kamera ʻepekemaLoaʻa iā PRNU haʻahaʻa haʻahaʻa e hāʻawi maikaʻi i kāna hāʻawi ʻana ma lalo o ka leo kiʻi kiʻi photon, ʻoi aku ma hope o ka hoʻoponopono ʻana ma luna o ka papa. No laila, ʻaʻole mālama ʻia i nā helu SNR i kēia manawa. Eia nō naʻe, he mea koʻikoʻi ka PRNU no kekahi mau kāmela a me nā noi, a ua hoʻokomo ʻia i ka hoʻohālikelike SNR ʻoi aku ka holomua no ka hoʻopiha. 'O ia ho'i, pono nā hoohalike i hā'awi 'ia no ka hapanui o nā pūnaewele CCD/CMOS akā 'a'ole pono e mālama 'ia e like me ka pili o ke ao holo'oko'a.
Nā ʻano walaʻau ma ka helu SNR
ʻO ka helu ʻana i ka SNR ʻaʻole ia e pili ana i ka hoʻohālikelike ʻana i kahi hōʻailona me kahi waiwai walaʻau hoʻokahi. I ka hoʻomaʻamaʻa ʻana, hāʻawi nā kumu leo kūʻokoʻa he nui, a he mea nui ka hoʻomaopopo ʻana iā lākou.
Ka leo pana
● Kumu: hōʻea helu helu o nā photon a i ʻole electrons.
● Nā unahi me ke kumu huinahā o ka hōʻailona.
● Nui i ka kiʻi kiʻi palena kiʻi kiʻi (astronomy, fluorescence microscopy).
Halau wela
● Ua kapa ʻia ʻo ia ka leo Johnson–Nyquist, i hana ʻia e ka neʻe electron i nā mea pale.
● Hoʻonui me ka mahana a me ka bandwidth.
● He mea nui i ka uila a me ke kamaʻilio uea.
Leo ʻeleʻele o kēia manawa
● Hoʻololi like ʻole i ke au ʻeleʻele i loko o nā mea ʻike.
● ʻOi aku ka nui ma nā hōʻike lōʻihi a i ʻole nā mea ʻike wela.
● Hoʻemi ʻia ma ka hoʻoluʻu ʻana i ka mea ʻike.
Heluhelu Halulu
● Noise mai nā mea hoʻonui a me ka hoʻololi analog-to-digital.
● Hoʻopaʻa ʻia i kēlā me kēia heluhelu ʻana, no laila koʻikoʻi i nā aupuni hōʻailona haʻahaʻa.
Ka leo nui
● Hoʻokomo ʻia e ka helu helu (ka hoʻopuni ʻana i nā pae ʻokoʻa).
● Mea nui ma nā ʻōnaehana haʻahaʻa-hohonu (e laʻa, leo 8-bit).
Kaona / Pūnaehana walaʻau
● EMI, crosstalk, mana lako ripple.
● Hiki ke lanakila inā maikaʻi ʻole ka pale ʻana.
ʻO ka hoʻomaopopo ʻana i kahi o kēia mau mea e kōkua i ke koho ʻana i ke ʻano kūpono a me ke ʻano hoʻohaʻahaʻa.
Nā hewa maʻamau i ka helu ʻana iā SNR
He mea maʻalahi ka loaʻa ʻana o nā ʻano 'pōkole' he nui e koho i kahi ratio hōʻailona-a-noise ma ke kiʻi. ʻOi aku ka liʻiliʻi o ka paʻakikī o kēia mau mea ma mua o nā hoʻohālikelike ʻē aʻe, e ʻae i ka maʻalahi o ke kiʻi ʻana mai kahi kiʻi ponoʻī ma mua o ka koi ʻana i ka ʻike o nā ʻāpana kamera e like me ka leo heluhelu, a i ʻole ʻelua. ʻO ka mea pōʻino, he hewa paha kēlā me kēia ʻano hana, a alakaʻi i nā hopena skewed a kōkua ʻole. Manaʻo ikaika ʻia e hoʻohana ʻia nā hoohalike kūʻē (a i ʻole ka mana holomua i nā hihia āpau.
ʻO kekahi o nā pōkole hoʻopunipuni maʻamau i loaʻa:
1、Ka hoʻohālikelike ʻana i ka ikaika o ka hōʻailona me ka ikaika o ka hope, ma nā pae hina. Ke ho'āʻo nei kēia ala e hoʻoholo i ka ʻike kamepiula, ka ikaika hōʻailona a i ʻole ka ratio hōʻailona i ka walaʻau ma ka hoʻohālikelike ʻana i ka ikaika kiʻekiʻe me ka ikaika hope. He hemahema loa kēia ala no ka mea, hiki i ka mana o ka pahupaʻi kiʻi ke hoʻonohonoho pono ʻole i ka ikaika o ke kua, hiki i ka loaʻa ke hoʻonohonoho i ka ikaika o ka hōʻailona, a ʻaʻohe hāʻawi o ka walaʻau ma ka hōʻailona a i ʻole ke kua i manaʻo ʻia.
2、Ka hoʻokaʻawale ʻana i nā piko hōʻailona e ka ʻokoʻa maʻamau o kahi wahi o nā pika hope. A i ʻole, ka hoʻohālikelike ʻana i nā waiwai kiʻekiʻe i ka walaʻau ʻike ma ke kua i hōʻike ʻia e kahi ʻaoʻao laina. Ke manaʻo nei ua unuhi pololei ʻia ka offset mai nā waiwai ma mua o ka hoʻokaʻawale ʻana, ʻo ka pōʻino koʻikoʻi i kēia ala ʻo ia ka hiki ʻana mai o ke kukui hope. ʻO kēlā me kēia kukui hope e lanakila maʻamau i ka walaʻau ma nā pika hope. Eia kekahi, ʻaʻole i noʻonoʻo ʻia ka walaʻau i ka hōʻailona o ka hoihoi, e like me ke kani pana.
3、Mean hōʻailona i loko o nā pika o ka hoihoi vs ka ʻokoʻa maʻamau o nā waiwai pika: Hoʻohālikelike a nānā paha i ka nui o ka hoʻololi ʻana o ka hōʻailona kiʻekiʻe ma waena o nā pika kokoke a i ʻole nā papa hope e kokoke ana i ka pololei ma mua o nā ʻano ala pōkole ʻē aʻe, akā ʻaʻole hiki ke pale i nā hopena ʻē aʻe e hoʻololi i nā waiwai, e like me ka hoʻololi ʻana i ka hōʻailona i loaʻa ʻole mai ka walaʻau. Hiki ke pololei ʻole kēia ʻano hana ma muli o nā helu pixel haʻahaʻa i ka hoʻohālikelike. ʻAʻole pono e poina ka unuhi ʻana o ka waiwai offset.
4、Ka helu ʻana i ka SNR me ka hoʻololi ʻole ʻana i nā ʻāpana ikaika o nā photoelectrons, a i ʻole me ka wehe ʻole ʻana i ka offset: No ka mea, ʻo ka leo kiʻi photon ka mea maʻamau ke kumu leo nui loa a hilinaʻi i ka ʻike o ka offset a me ka loaʻa ʻana o ke kāmela no ke ana ʻana, ʻaʻole hiki ke pale i ka helu ʻana i nā photoelectrons no ka helu SNR.
5、Ka hoʻoholo ʻana iā SNR ma ka maka: ʻOiai ma kekahi mau kūlana e hoʻoholo ai a hoʻohālikelike paha iā SNR ma ka maka hiki ke hoʻohana, aia kekahi mau pilikia i manaʻo ʻole ʻia. ʻOi aku ka paʻakikī o ka hoʻoholo ʻana iā SNR i nā pika waiwai nui ma mua o ka waiwai haʻahaʻa a i ʻole nā pika hope. Hiki i nā hopena maʻalahi ke pāʻani: No ka laʻana, hiki i nā mea nānā kamepiula ʻokoʻa ke hana i nā kiʻi me ka ʻokoʻa ʻokoʻa. Eia kekahi, ʻo ka hōʻike ʻana i nā kiʻi ma nā pae zoom like ʻole i ka lako polokalamu hiki ke hoʻololi nui i ka ʻike maka o ka walaʻau. He pilikia nui kēia inā e ho'āʻo ana e hoʻohālikelike i nā kāmela me nā ʻokoʻa o ka nui pixel space space. ʻO ka hope, hiki i ka hiki ʻana o ke kukui ʻula ke hoʻopau i ka hoʻāʻo ʻana e hoʻokolokolo iā SNR me ka ʻike maka.
Nā noi o SNR
ʻO SNR kahi metric ākea me nā noi ākea:
● Hoʻopaʻa Leo & Mele: Hoʻoholo i ka moʻoʻōlelo, ka laulā ikaika, a me ka hilinaʻi o nā hoʻopaʻa leo.
● Kūkākūkā Uila: Pili pololei ʻo SNR i nā helu kuhi hewa (BER) a me ka hoʻokomo ʻikepili.
● Kiʻi ʻepekema: Ma ka ʻike hōkū, pono ka SNR kiʻekiʻe ke ʻike ʻana i nā hōkū nāwaliwali i ka ʻālohilohi o ka lani.
● Lapaʻau Lapaʻau: ECG, MRI, a me CT scans e hilinaʻi i ka SNR kiʻekiʻe e hoʻokaʻawale i nā hōʻailona mai ka leo physiological.
● Nā kiʻi paʻi kiʻi a me nā kiʻi paʻi kiʻi: Hoʻohana nā kāmeʻa mea kūʻai aku a me nā mea ʻike CMOS ʻepekema i ka SNR e hoʻohālikelike i ka hana ma ka mālamalama haʻahaʻa.
Hoʻomaikaʻi i ka SNR
No ka mea he ana koʻikoʻi ʻo SNR, hoʻoikaika nui i ka hoʻomaikaʻi ʻana. Loaʻa nā papahana:
ʻO nā ala paʻahana
● E hoʻohana i nā mea ʻike maikaʻi me ke au ʻeleʻele haʻahaʻa.
● E hoʻopili i ka pale a me ke kahua e hoʻemi i ka EMI.
● ʻO nā mea ʻike ʻoluʻolu e hoʻopau i ka walaʻau wela.
Hoʻokokoke lako polokalamu
● Hoʻopili i nā kānana kikohoʻe e wehe i nā alapine makemake ʻole.
● E hoʻohana i ka awelika ma nā papa he nui.
● Hoʻohana i nā algorithm no ka hoʻohaʻahaʻa ʻana i ka walaʻau ma ke kiʻi a i ʻole ka hoʻoili leo.
Pixel Binning a me kona hopena ma SNR
ʻO ka hopena o ka binning ma ka ratio signal-to-noise e pili ana i ka ʻenehana kamera a me ka ʻano sensor, no ka mea, hiki ke ʻokoʻa ka hana walaʻau o nā pahu pahu a me nā kāmela i hoʻopaʻa ʻole ʻia.
Hiki i nā kāmeʻa CCD ke hōʻuluʻulu i ka hoʻopiʻi 'on-chip' pili pili. Hoʻokahi wale nō manawa o ka walaʻau heluhelu, ʻoiai e hōʻuluʻulu ʻia ka hōʻailona ʻeleʻele mai kēlā me kēia pika.
Hana ʻia ka hapa nui o nā kiʻi paʻi kiʻi CMOS i waho-chip binning, ʻo ia hoʻi ke ana mua ʻia nā waiwai (a hoʻokomo ʻia ka leo leo), a laila hōʻuluʻulu ʻia me ka helu helu. Piʻi ka walaʻau heluhelu no ia mau hōʻuluʻulu ʻana me ka hoʻonui ʻana i ke kumu huinahā o ka helu o nā pika i hōʻuluʻulu ʻia, ʻo ia hoʻi ma ka helu 2 no ka 2x2 binning.
Ma muli o ka paʻakikī o ka hana leo o nā mea ʻike, no nā noi quantitative pono e ana i ka offset, loaʻa, a heluhelu i ka walaʻau o ka pahupaʻikiʻi ma ke ʻano binned, a hoʻohana i kēia mau waiwai no ka hoʻohālikelike hōʻailona-a-noise ratio.
Ka hopena
ʻO ka ratio signal-to-noise (SNR) kekahi o nā ana nui i ka ʻepekema, ʻenekinia, a me ka ʻenehana. Mai ka wehewehe ʻana i ka mālamalama i nā kelepona kelepona a hiki i ka ʻike ʻana i nā galaxies mamao, hoʻokumu ʻo SNR i ka maikaʻi o ke ana a me nā ʻōnaehana kamaʻilio. ʻAʻole ʻo ka haku ʻana i ka SNR wale nō e pili ana i ka hoʻopaʻanaʻau ʻana i nā ʻōlelo hoʻohālikelike - e pili ana i ka hoʻomaopopo ʻana i nā manaʻo, nā palena, a me nā kālepa honua maoli. Mai kēia hiʻohiʻona, hiki i nā ʻenekinia a me nā mea noiʻi ke hana i nā ana hilinaʻi a me nā ʻōnaehana hoʻolālā e unuhi i nā ʻike koʻikoʻi ʻoiai i nā kūlana walaʻau.
Makemake ʻoe e aʻo hou aku? E nānā i nā ʻatikala pili:
Tucsen Photonics Co., Ltd. Ua mālama ʻia nā kuleana āpau. Ke helu ʻana, e ʻoluʻolu e hoʻomaopopo i ke kumu:www.tucsen.com
