Sigma/Foveon Questions
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From: Ray Fischer on 28 Apr 2010 13:15 Alfred Molon <alfred_molon(a)yahoo.com> wrote: >> David J Taylor >> > > it may be a very accurate pixel, but it's still a *single* pixel and it >> > > differs from foveon because each measurement is independent. >> > > >> > > with foveon, the layers are tightly intertwined. unlike the pretty (and >> > > misleading) pictures in their ads, the layers do *not* measure red, >> > > green and blue, that's only a result of (here it comes), interpolation. >> > > in fact, there is more interpolation with foveon than there is with >> > > bayer which is comical, actually. >> > >> > Agreed. >> > >> > [Although I would prefer not use the term "interpolation" to describe the >> > 3 x 3 matrix processing to convert the three Foveon sensed values into >> > three RGB values. Something like "colour correction", perhaps?] >> >> well, it *is* interpolating the overlapping spectra to figure out the >> incident colour is (and not all that accurately either). > >It's three separate spectral measurements per pixel, while a Bayer >sensor has only one. > >Also, Bayer does not measure luminance at the pixel level, while a full >colour sensor does. > >In any case we were talking about *spatial* interpolation, which Bayer >does to generate the final image. Since the final image is the same size at the sensor then your statement cannot be true. -- Ray Fischer rfischer(a)sonic.net
From: nospam on 28 Apr 2010 17:26 In article <MPG.2642778ae8ef886598c2bb(a)news.supernews.com>, Alfred Molon <alfred_molon(a)yahoo.com> wrote: > It's three separate spectral measurements per pixel, while a Bayer > sensor has only one. and bayer calculates the other two. at the end of the day, both produce rgb, and oddly enough, bayer is more accurate. > Also, Bayer does not measure luminance at the pixel level, while a full > colour sensor does. neither measures full luminance, however, both calculate it. > In any case we were talking about *spatial* interpolation, which Bayer > does to generate the final image. nope. it fills in the holes.
From: Alfred Molon on 29 Apr 2010 02:08 In article <280420101626373798%nospam(a)nospam.invalid>, nospam says... > > > It's three separate spectral measurements per pixel, while a Bayer > > sensor has only one. > > and bayer calculates the other two. at the end of the day, both produce > rgb, and oddly enough, bayer is more accurate. Obviously Bayer is not more accurate. And how could it be, with just 1/3 of the needed information? > > Also, Bayer does not measure luminance at the pixel level, while a full > > colour sensor does. > > neither measures full luminance, however, both calculate it. A full colour sensor measures luminance at the pixel level. Bayer does not. > > In any case we were talking about *spatial* interpolation, which Bayer > > does to generate the final image. > > nope. it fills in the holes. With guesses, which often are wrong. -- Alfred Molon ------------------------------ Olympus E-series DSLRs and micro 4/3 forum at http://tech.groups.yahoo.com/group/MyOlympus/ http://myolympus.org/ photo sharing site
From: nospam on 29 Apr 2010 02:16 In article <MPG.264340d3b9a8204498c2bc(a)news.supernews.com>, Alfred Molon <alfred_molon(a)yahoo.com> wrote: > > > It's three separate spectral measurements per pixel, while a Bayer > > > sensor has only one. > > > > and bayer calculates the other two. at the end of the day, both produce > > rgb, and oddly enough, bayer is more accurate. > > Obviously Bayer is not more accurate. And how could it be, with just 1/3 > of the needed information? obviously, based on what? delta-e measurements show foveon having *less* accurate colour than bayer. foveon also has a lot more noise than bayer, particularly at higher isos. > > > Also, Bayer does not measure luminance at the pixel level, while a full > > > colour sensor does. > > > > neither measures full luminance, however, both calculate it. > > A full colour sensor measures luminance at the pixel level. Bayer does > not. foveon does not because it doesn't measure rgb. *both* require processing. maybe a mythical future sensor might do better than either foveon or bayer, but that doesn't currently exist. > > > In any case we were talking about *spatial* interpolation, which Bayer > > > does to generate the final image. > > > > nope. it fills in the holes. > > With guesses, which often are wrong. it's not guessing, it's calculated, and it's quite accurate. see above, regarding delta-e measurements.
From: Ray Fischer on 29 Apr 2010 06:18
Alfred Molon <alfred_molon(a)yahoo.com> wrote: > nospam says... >> > It's three separate spectral measurements per pixel, while a Bayer >> > sensor has only one. >> >> and bayer calculates the other two. at the end of the day, both produce >> rgb, and oddly enough, bayer is more accurate. > >Obviously Bayer is not more accurate. And how could it be, with just 1/3 >of the needed information? 1/3 * 18,000,000 > 3/3 * 4,600,000 -- Ray Fischer rfischer(a)sonic.net |