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Cum scapati de bad pixels si dead pixels in 3 min
Last Updated: Jan 10 2012 21:45, Started by
dlbogdan
, Jun 14 2006 11:16
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#20
Posted 14 June 2006 - 14:46
msdan, on Jun 14 2006, 15:39, said: bogdan, e prima oara cand faci testul? ai idee cat timp se mentine starea "curata"? Nu e prima oara cand recalibrez, dar ESTE prima oara prin metoda asta DURA. Nu am idee cat se mentine. acrac, on Jun 14 2006, 15:44, said: cam suspect de mare diferenta vrei originalele neatinse de photoshop? |
#21
Posted 14 June 2006 - 14:49
hehe nu, ca doar nu faci misto de noi.
cum e cu harta asta de bias? tine cate o valoare pt fiecare pixel ? |
#22
Posted 14 June 2006 - 14:54
uite de ex. fa vreo 50 de cadre si pe urma incearca din nou cu capacul pus...
ma gandesc sa nu fie o chestie de genul stergere caseta audio - cand cred ca toate particulele magnetice au acceasi orientare, ca apoi la prima inregistrare sa ai aceeasi calitate, chiar mai slaba... |
#23
Posted 14 June 2006 - 14:55
acrac, on Jun 14 2006, 15:49, said: hehe nu, ca doar nu faci misto de noi. cum e cu harta asta de bias? tine cate o valoare pt fiecare pixel ? da. tine o valoare de bias de 36 biti pentru fiecare pixel. aceasta valoare de bias se traduce prin nivelul calibrat al tensiunii pt. fiecare canal. EDIT: unele aparate foto folosesc alta tehnologie pentru a scapa de acesti pixeli corupti. EDIT2: .... tehnologie care se pare nu implica o calibrare efectiva prin modificarea unei tensiuni per canal ci mai degraba scoaterea din calcul a pixelului cu totul si inlocuirea lui cu o medie a pixelilor vecini. Aceasta tehnologie (folosita la Canon de exemplu) nu se poate folosi de metoda mea de mai sus deoarece ar implica o scadere masiva a rezolutiei. (nu definitiv, nu va speriati, puteti testa... la urmatoarea recalibrare normala fara pre-heat, revine totul la normal) DECI, unele aparate pot castiga din asta fara nici o pierdere, altele pot castiga dar cu pierderi. Edited by dlbogdan, 14 June 2006 - 15:07. |
#24
Posted 14 June 2006 - 15:09
msdan, on Jun 14 2006, 15:54, said: uite de ex. fa vreo 50 de cadre si pe urma incearca din nou cu capacul pus... ma gandesc sa nu fie o chestie de genul stergere caseta audio - cand cred ca toate particulele magnetice au acceasi orientare, ca apoi la prima inregistrare sa ai aceeasi calitate, chiar mai slaba... Am incercat. Am facut 100 de cadre. Nu apare zgomot sesizabil in plus. |
#25
Posted 14 June 2006 - 15:17
Dacă încearcă cineva cu un 350d să posteze rezultatul vă rog, deși mă îndoiesc de vreun efect :|
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#26
Posted 14 June 2006 - 15:30
ezekio, on Jun 14 2006, 16:17, said: Dacă încearcă cineva cu un 350d să posteze rezultatul vă rog, deși mă îndoiesc de vreun efect :| Confirm. Canon NU are nici un algoritm de remapare automata a pixelilor. (Poate ca CMOS-ul e mai putin predispus la asa ceva, cu toate ca am vazut zgomot mai mare la iso3200 la canon decat la minolta al meu dupa remapare) quote from http://forums.dprevi...message=9108799 "I can't understand why all digicams don't have pixel remapping built into the FW. Doc Tonic wrote: > There are MANY people here with tons of dead/hot pixels as the > camera ages....just a simple fact that as the camera gets older you > will get dead/hot pixels. Do a search and see how many of us have > them. I will get them fixed, but I'll wait until my shutter breaks > before sending the camera in. You can easily fix them in photoshop > and all canon will do is remap your sensor anyways. " |
#27
Posted 14 June 2006 - 15:36
dlbogdan, on Jun 14 2006, 16:30, said: Confirm. Canon NU are nici un algoritm de remapare automata a pixelilor. (Poate ca CMOS-ul e mai putin predispus la asa ceva, cu toate ca am vazut zgomot mai mare la iso3200 la canon decat la minolta al meu dupa remapare) |
#28
Posted 14 June 2006 - 15:37
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#29
Posted 14 June 2006 - 15:55
Informatii in plus privind Canon:
"Actually from what I heard Canon did offer a program to remove the dead pixels that can be used by the owner of the camera. However, they stopped shipping that CD already. I also asked Canon once why they do not allow remapping of the dead pixels on the firmware. Their stance, or for that matter the answer is somewhat conservative. They claim that if they allow the customer to remap the sensor themself either via camera menus or software, and if it messes up, they will have more work to do trying to undo the mess. Sounds to be like they just don't want to go through all that trouble. Been looking for that CD all over but up till now, no luck in finding it.." "If the customer could remap the sensor, he/she could unmap it too. Then he/she could see how bad it really is. No way, Sir!" http://forums.dprevi...message=9135614 Asadar Canonisti... cautati programul cu pricina daca aveti probleme. Daca sunteti multumiti de calitatea imaginii nu va mai bateti capul. |
#30
Posted 14 June 2006 - 16:01
dlbogdan, on Jun 14 2006, 16:37, said: Nu cred. Cred ca in general e invers, doar ca CCD-ul e mai flexibil si poate fi "curatat electronic". While CMOS sensors excel in the capture of outdoor pictures on sunny days, they suffer in low light conditions. Their sensitivity to light is decreased because part of each photosite is covered with circuitry that filters out noise and performs other functions. The percentage of a pixel devoted to collecting light is called the pixel’s fill factor. CCDs have a 100% fill factor but CMOS cameras have much less. The lower the fill factor, the less sensitive the sensor is and the longer exposure times must be. Too low a fill factor makes indoor photography without a flash virtually impossible. To compensate for lower fill-factors, micro-lenses can be added to each pixel to gather light from the insensitive portions of the pixel and "focus" it down to the photosite. In addition, the circuitry can be reduced so it doesn't cover as large an area. CMOS sensors have a higher noise level than CCDs so the processing time between pictures is higher as these sensors use digital signal processing (DSP) to reduce or eliminate the noise. |
#31
Posted 14 June 2006 - 16:08
Re-maparea se poate face si software, trebuie doar sa inlocuiesti pixelii afectati cu informatie interpolata. Cel putin la Pentax e teoretic simplu, raw-ul e un soi de tiff necomprimat
Poate n-ar strica sa cautam asemenea programele? Btw parca am auzit ca se pot face ceva action-uri in Photostop... |
#32
Posted 14 June 2006 - 16:14
dlbogdan, on Jun 14 2006, 16:37, said: Nu cred. Cred ca in general e invers, doar ca CCD-ul e mai flexibil si poate fi "curatat electronic". http://www.dalsa.com...ccd_vs_cmos.asp |
#33
Posted 14 June 2006 - 16:22
Da, am citit si eu, asta era inainte sa apara wonder D30 care cica e de generatie noua, etc. Generatiile actuale de camere sunt cam tot pe acolo una fata de cealalta, senzorul de 6 mp CCD de la Sony fiind ceva mai zgomotos decat CMOS-ul de 8 (cu sau fara .2) de la Canon... dar CCD-ul are avantaj de remapping.
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#34
Posted 14 June 2006 - 17:21
#35
Posted 14 June 2006 - 17:40
Icss, vorbeam de raw-ul Pentax - ar fi bine sa mai extinzi nitel citatul. Si da, in esenta este un tiff cu tag-uri specifice care stocheaza imaginea raw si nu un bitmap RGB.
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#36
Posted 14 June 2006 - 17:57
Nae65, on Jun 14 2006, 17:01, said: While CMOS sensors excel in the capture of outdoor pictures on sunny days, they suffer in low light conditions. Their sensitivity to light is decreased because part of each photosite is covered with circuitry that filters out noise and performs other functions. The percentage of a pixel devoted to collecting light is called the pixel’s fill factor. CCDs have a 100% fill factor but CMOS cameras have much less. The lower the fill factor, the less sensitive the sensor is and the longer exposure times must be. Too low a fill factor makes indoor photography without a flash virtually impossible. To compensate for lower fill-factors, micro-lenses can be added to each pixel to gather light from the insensitive portions of the pixel and "focus" it down to the photosite. In addition, the circuitry can be reduced so it doesn't cover as large an area. CMOS sensors have a higher noise level than CCDs so the processing time between pictures is higher as these sensors use digital signal processing (DSP) to reduce or eliminate the noise. Man, tu dai citate de pe vremea lu' bunicu (in timp digital). Una este senzorul CMOS folosit in telefonul mobil si altul este senzorul CMOS folosit pe Canon 1D2S (8000$). CMOS "state of the art" vs CCD "state of the art? Arunca un ochi aici . Desi D200-le foloseste senzor CCD si un algoritm de noise reduction foarte agresiv (a se vedea rezolutia net inferioara la iso mare comparativ cu 30D) acesta ramane totusi mult mai zgomotos decat umilul CMOS al lui 30D/20D/5D. Cat despre Canon si imposibilitatea de remapare a pixelilor. Nu m-a interesat domeniul, rar fac zoom la 100%. Tot ce stiu este ca aveam un pixel alb care in timp a disparut. Edited by Dragos Jianu, 14 June 2006 - 18:01. |
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