Bayer sensor and MX

In article <wNadnSk0HdDS-THanZ2dneKdnZydnZ2d RemoveThis @novis.pt>, Sosumi
<sosumi RemoveThis @home.nl> wrote:

> The way the Bayer sensor works, it "makes up" color information depending on
> the surrounding pixels.

it doesn't 'make up' colour information, it uses multiple pixels to
calculate it.

> And also: do all Bayer sensor work exactly the same, or is there a
> difference in Nikon, Canon, older, newer models?

the specific demosaic algorithm used will be different, just as there
are differences among different raw converters. also, newer cameras
may have a better algorithms than older ones.
 >> Stay informed about: Bayer sensor and MX 

Sosumi wrote:
> What I was wondering: do the pixel interpolation always work the same way?

Ask Mr.G about Drizzle Algorithm, such as
http://www.astrosurf.com/buil/iris/tutorial2/doc12_us.htm
Don't forget that
> Drizzle is adapted only to undersampled images


--
Frédéric
 >> Stay informed about: Bayer sensor and MX 

"Sosumi" <sosumi.TakeThisOut@home.nl> schreef in bericht
news:wNadnSk0HdDS-THanZ2dneKdnZydnZ2d@novis.pt...
> The way the Bayer sensor works, it "makes up" color information depending
> on the surrounding pixels. But if you do multiple exposures with exactly
> the same scene, the picture gets more sharp according to the amount of
> exposures.

No the picture does not get more sharp. If there is a lot of noise in one
normal
picture, the definition of the picture get's a littlebit better, but for
most normal
pictures (in normal light) taking more pictures of the same scene does not
make
it sharper.

In theory small movements of the camera and adjusting for these movements
when adding the pictures, will give a better picture and less risc of moire.
In theory this method can even make pictures sharper, but then you need
a very large amount of the 'same' pictures to get the pictures noticeble
sharper.


> Much is due to the fact that noise is distributed randomly and hence, the
> same place where a "piece" of noise was before, it's over written with
> data the next exposure.
Multiple pictures will reduce the noice, but with correctly exposed pictures
there is not a lot of noise. (Long exposure pictures will benefit from
multiple
exposure, but not normally exposed pictures).




> What I was wondering: do the pixel interpolation always work the same way?
> Or is this also slightly random (shifting)? So do you, in fact, get more
> information or only less noise? It just seems hard to believe, that every
> take of a picture would give exactly (I mean pixel deep peeping) the same
> result.
>
> And also: do all Bayer sensor work exactly the same, or is there a
> difference in Nikon, Canon, older, newer models?

There are some variations.
Most sensors have 2 greens, 1 red and 1 blue for every four cells in a
square.
There are sensors where the second green is replace by another color.
There are sensors which are not RGB, but YMC, but I haven's seen them them
lately
in camera's.

Normal Bayer sensors

GRGRGRGR
BGBGBGBG
GRGRGRGR
BGBGBGBG

Interpolation which is most simple is that, on each pixel

Green pixel (position).
Green = G (from the pixel)
Red= (Rl+Rr)/2 from the left and the right
Bleu = (Bu+Bd)/2 from the up and down bleu.

Red pixel (position).
Green = (Gl+Gr+Gu+Gd)/4
Red = R (from the pixel)
Bleu = (B+B+B+B)/4 from the 4 corners of R

Bleu pixel (position).
Green = (Gl+Gr+Gu+Gd)/4
Red = (R+R+R+R) /4 from the 4 corners of B
Bleu = B (from the pixel)

This is without sharpening or any other fancy stuf.
(In general sharpening subtracts a little bit of pixels laying further
away).

When using multiple exposure with shifted pixels, something similar is done,
with far smaller pixels, where the 'large' pixels are shifted over the small
pixels.
Using sharpening this will result in a slightly sharper picture.

As you can see the Red and Bleu pixels (positions) get the information of
the
Bleu and Red colors from quite some distance.
The resolution for red only or bleu only is significant less than for black
and white.

ben



>
>
> --
> Sosumi
>
 >> Stay informed about: Bayer sensor and MX 

On Feb 8, 9:10 pm, Fred <f....DeleteThis@somewhere.com> wrote:
> Sosumi wrote:
> > What I was wondering: do the pixel interpolation always work the same way?
>
> Ask Mr.G about Drizzle Algorithm, such ashttp://www.astrosurf.com/buil/iris/tutorial2/doc12_us.htm
> Don't forget that
>
> > Drizzle is adapted only to undersampled images
>

But that is quite different: it exploits shifts in the input images to
increase the spatial sampling rate, as opposed to using an
interpolation that has a stochastic element. No?
 >> Stay informed about: Bayer sensor and MX 

On Feb 9, 3:07 am, Jeremy Nixon <~$!~( )@( )u.defocus.net> wrote:
> Sosumi <sos....DeleteThis@home.nl> wrote:
> > You're wrong. I took several pictures and the more MX times, the sharper
> > the picture. Less noise is sharper. If you blow the pictures up to 100%
> > you clearly see normal noise, grain or pixels, while with the MX
> > pixtures, pixels are hardly visible: it's much smoother.
>
> No... you're wrong. It doesn't get sharper, it simply reduces the noise.
> Less noise isn't "sharper", it's "less noise". You are increasing the
> signal to noise ratio.
>
> > With 5 -10 exposures on one picture the differense is already very
> > noticeable.
>
> Multiple exposure blending reduces noise by a known and mathematically
> demonstrable amount. Three exposures doubles the signal-to-noise ratio.
> Nine exposures triples it.
>

I'd say that four exposures double S/N, etc. No?

Anyway I think we're all wasting our time (unless someone reading this
thread later finds some of the replies interesting). It looks like the
OP is just stupidly attacking (and not for the first time).
 >> Stay informed about: Bayer sensor and MX 

"ben brugman" <ben.DeleteThis@niethier.nl> wrote in message
news:74353$47acac5b$53557893$7430@cache120.multikabel.net...
>
> "Sosumi" <sosumi.DeleteThis@home.nl> schreef in bericht
> news:wNadnSk0HdDS-THanZ2dneKdnZydnZ2d@novis.pt...
>> The way the Bayer sensor works, it "makes up" color information depending
>> on the surrounding pixels. But if you do multiple exposures with exactly
>> the same scene, the picture gets more sharp according to the amount of
>> exposures.
>
> No the picture does not get more sharp. If there is a lot of noise in one
> normal
> picture, the definition of the picture get's a littlebit better, but for
> most normal
> pictures (in normal light) taking more pictures of the same scene does not
> make
> it sharper.

You're wrong. I took several pictures and the more MX times, the sharper the
picture. Less noise is sharper. If you blow the pictures up to 100% you
clearly see normal noise, grain or pixels, while with the MX pixtures,
pixels are hardly visible: it's much smoother.

> In theory small movements of the camera and adjusting for these movements
> when adding the pictures, will give a better picture and less risc of
> moire.
> In theory this method can even make pictures sharper, but then you need
> a very large amount of the 'same' pictures to get the pictures noticeble
> sharper.

With 5 -10 exposures on one picture the differense is already very
noticeable.

>> Much is due to the fact that noise is distributed randomly and hence, the
>> same place where a "piece" of noise was before, it's over written with
>> data the next exposure.
> Multiple pictures will reduce the noice, but with correctly exposed
> pictures
> there is not a lot of noise. (Long exposure pictures will benefit from
> multiple
> exposure, but not normally exposed pictures).

No, you're wrong. See above.


>> What I was wondering: do the pixel interpolation always work the same
>> way? Or is this also slightly random (shifting)? So do you, in fact, get
>> more information or only less noise? It just seems hard to believe, that
>> every take of a picture would give exactly (I mean pixel deep peeping)
>> the same result.
>>
>> And also: do all Bayer sensor work exactly the same, or is there a
>> difference in Nikon, Canon, older, newer models?
>
> There are some variations.
> Most sensors have 2 greens, 1 red and 1 blue for every four cells in a
> square.
> There are sensors where the second green is replace by another color.
> There are sensors which are not RGB, but YMC, but I haven's seen them them
> lately
> in camera's.
>
> Normal Bayer sensors
>
> GRGRGRGR
> BGBGBGBG
> GRGRGRGR
> BGBGBGBG
>
> Interpolation which is most simple is that, on each pixel
>
> Green pixel (position).
> Green = G (from the pixel)
> Red= (Rl+Rr)/2 from the left and the right
> Bleu = (Bu+Bd)/2 from the up and down bleu.
>
> Red pixel (position).
> Green = (Gl+Gr+Gu+Gd)/4
> Red = R (from the pixel)
> Bleu = (B+B+B+B)/4 from the 4 corners of R
>
> Bleu pixel (position).
> Green = (Gl+Gr+Gu+Gd)/4
> Red = (R+R+R+R) /4 from the 4 corners of B
> Bleu = B (from the pixel)
>
> This is without sharpening or any other fancy stuf.
> (In general sharpening subtracts a little bit of pixels laying further
> away).
>
> When using multiple exposure with shifted pixels, something similar is
> done,
> with far smaller pixels, where the 'large' pixels are shifted over the
> small pixels.
> Using sharpening this will result in a slightly sharper picture.
>
> As you can see the Red and Bleu pixels (positions) get the information of
> the
> Bleu and Red colors from quite some distance.
> The resolution for red only or bleu only is significant less than for
> black and white.
>
> ben
>
--
Sosumi
 >> Stay informed about: Bayer sensor and MX 

Sosumi <sosumi RemoveThis @home.nl> wrote:

> You're wrong. I took several pictures and the more MX times, the sharper
> the picture. Less noise is sharper. If you blow the pictures up to 100%
> you clearly see normal noise, grain or pixels, while with the MX
> pixtures, pixels are hardly visible: it's much smoother.

No... you're wrong. It doesn't get sharper, it simply reduces the noise.
Less noise isn't "sharper", it's "less noise". You are increasing the
signal to noise ratio.

> With 5 -10 exposures on one picture the differense is already very
> noticeable.

Multiple exposure blending reduces noise by a known and mathematically
demonstrable amount. Three exposures doubles the signal-to-noise ratio.
Nine exposures triples it.

--
Jeremy Nixon | address in header is valid
(formerly jeremy RemoveThis @exit109.com)
http://www.flickr.com/photos/100mph/
 >> Stay informed about: Bayer sensor and MX 

Thanks Ben for a nice clear explanation. This can be really effective
for astronomy but that is pushing the limits so far beyond normal
photography. For astro work they make amazing cameras for astounding
prices, extra high performance, but I have *never* heard of anyone using
those cameras for conventional photography because it just doesn't
matter. If it mattered, you would see someone using those $13,000 cooled
high performance scientific cameras for advertising diamonds or sports
or Hollywood movies or something but nobody does.

ben brugman wrote:
>
> "Sosumi" <sosumi DeleteThis @home.nl> schreef in bericht
> news:wNadnSk0HdDS-THanZ2dneKdnZydnZ2d@novis.pt...
>> The way the Bayer sensor works, it "makes up" color information
>> depending on the surrounding pixels. But if you do multiple exposures
>> with exactly the same scene, the picture gets more sharp according to
>> the amount of exposures.
>
> No the picture does not get more sharp. If there is a lot of noise in one normal
> picture, the definition of the picture get's a littlebit better, but for most normal
> pictures (in normal light) taking more pictures of the same scene does not make
> it sharper.
>
> In theory small movements of the camera and adjusting for these movements
> when adding the pictures, will give a better picture and less risc of moire.
> In theory this method can even make pictures sharper, but then you need
> a very large amount of the 'same' pictures to get the pictures noticeble sharper.
>
>> Much is due to the fact that noise is distributed randomly and hence,
>> the same place where a "piece" of noise was before, it's over written
>> with data the next exposure.
>
> Multiple pictures will reduce the noice, but with correctly exposed pictures
> there is not a lot of noise. (Long exposure pictures will benefit from multiple
> exposure, but not normally exposed pictures).
>
>> What I was wondering: do the pixel interpolation always work the same
>> way? Or is this also slightly random (shifting)? So do you, in fact,
>> get more information or only less noise? It just seems hard to
>> believe, that every take of a picture would give exactly (I mean pixel
>> deep peeping) the same result.
>>
>> And also: do all Bayer sensor work exactly the same, or is there a
>> difference in Nikon, Canon, older, newer models?
>
> There are some variations.
> Most sensors have 2 greens, 1 red and 1 blue for every four cells in a square.
> There are sensors where the second green is replace by another color.
> There are sensors which are not RGB, but YMC, but I haven's seen them them lately
> in camera's.
>
> Normal Bayer sensors
>
> GRGRGRGR
> BGBGBGBG
> GRGRGRGR
> BGBGBGBG
>
> Interpolation which is most simple is that, on each pixel
>
> Green pixel (position).
> Green = G (from the pixel)
> Red= (Rl+Rr)/2 from the left and the right
> Bleu = (Bu+Bd)/2 from the up and down bleu.
>
> Red pixel (position).
> Green = (Gl+Gr+Gu+Gd)/4
> Red = R (from the pixel)
> Bleu = (B+B+B+B)/4 from the 4 corners of R
>
> Bleu pixel (position).
> Green = (Gl+Gr+Gu+Gd)/4
> Red = (R+R+R+R) /4 from the 4 corners of B
> Bleu = B (from the pixel)
>
> This is without sharpening or any other fancy stuf.
> (In general sharpening subtracts a little bit of pixels laying further away).
>
> When using multiple exposure with shifted pixels, something similar is done,
> with far smaller pixels, where the 'large' pixels are shifted over the small pixels.
> Using sharpening this will result in a slightly sharper picture.
>
> As you can see the Red and Bleu pixels (positions) get the information of the
> Bleu and Red colors from quite some distance.
> The resolution for red only or bleu only is significant less than for black and white.
 >> Stay informed about: Bayer sensor and MX 

On Feb 9, 1:28 pm, "Sosumi" <sos....DeleteThis@home.nl> wrote:
> "acl" <achilleaslazari....DeleteThis@yahoo.co.uk> wrote in message
>
> news:4eb37964-e5fa-4f1a-b88b-4704b3b553e6@d21g2000prf.googlegroups.com...
>
>
>
> > On Feb 9, 3:07 am, Jeremy Nixon <~$!~( )@( )u.defocus.net> wrote:
> >> Sosumi <sos....DeleteThis@home.nl> wrote:
> >> > You're wrong. I took several pictures and the more MX times, the
> >> > sharper
> >> > the picture. Less noise is sharper. If you blow the pictures up to 100%
> >> > you clearly see normal noise, grain or pixels, while with the MX
> >> > pixtures, pixels are hardly visible: it's much smoother.
>
> >> No... you're wrong. It doesn't get sharper, it simply reduces the noise.
> >> Less noise isn't "sharper", it's "less noise". You are increasing the
> >> signal to noise ratio.
>
> >> > With 5 -10 exposures on one picture the differense is already very
> >> > noticeable.
>
> >> Multiple exposure blending reduces noise by a known and mathematically
> >> demonstrable amount. Three exposures doubles the signal-to-noise ratio.
> >> Nine exposures triples it.
>
> > I'd say that four exposures double S/N, etc. No?
>
> > Anyway I think we're all wasting our time (unless someone reading this
> > thread later finds some of the replies interesting). It looks like the
> > OP is just stupidly attacking (and not for the first time).
>
> If you can't win a discussion, you can always start calling names. Real
> grown up. Now go get your pacifier and let adult people have a serious
> conversation.
>

OK, but what discussion am I trying to win?
 >> Stay informed about: Bayer sensor and MX 

On Feb 9, 5:01 pm, "ben brugman" <b....TakeThisOut@niethier.nl> wrote:
> "Paul Furman" <pa....TakeThisOut@-edgehill.net> schreef in berichtnews:Nwbrj.8782$Ch6.799@newssvr11.news.prodigy.net...
>
> > Thanks Ben for a nice clear explanation. This can be really effective for
> > astronomy but that is pushing the limits so far beyond normal photography.
> > For astro work they make amazing cameras for astounding prices, extra high
> > performance, but I have *never* heard of anyone using those cameras for
> > conventional photography because it just doesn't matter. If it mattered,
> > you would see someone using those $13,000 cooled high performance
> > scientific cameras for advertising diamonds or sports or Hollywood movies
> > or something but nobody does.
>
> The part of the Bayer sensor is the practical part.
> The part of the multiexposure to 'extract' more resolution is impractical at
> least, but theoretically correct.
> I'ts a nice thought experiment. (No and for normal people it is totaly
> unfeasable).

Actually it's not that far fetched, you can use registax to do both
stacking and what you describe.
 >> Stay informed about: Bayer sensor and MX 

"Jeremy Nixon" <~$!~( )@( )u.defocus.net> wrote in message
news:13qprmgcschc362@corp.supernews.com...
> Sosumi <sosumi DeleteThis @home.nl> wrote:
>
>> You're wrong. I took several pictures and the more MX times, the sharper
>> the picture. Less noise is sharper. If you blow the pictures up to 100%
>> you clearly see normal noise, grain or pixels, while with the MX
>> pixtures, pixels are hardly visible: it's much smoother.
>
> No... you're wrong. It doesn't get sharper, it simply reduces the noise.
> Less noise isn't "sharper", it's "less noise". You are increasing the
> signal to noise ratio.

Do you even understand the meaning of "sharp" in this context?
According to one of many meanings of sharp in the American Heritage
Dictionary:
"Having clear form and detail: a sharp photographic image."

It doesn't get any more clear than that.
A picture with noise is *not* clear and detail is lost. Add more noise and
even more detail is lost. Or do you want to say, that adding noise to a
picture doesn't have an effect on the sharpness?


--
Sosumi
 >> Stay informed about: Bayer sensor and MX 

"acl" <achilleaslazarides RemoveThis @yahoo.co.uk> wrote in message
news:4eb37964-e5fa-4f1a-b88b-4704b3b553e6@d21g2000prf.googlegroups.com...
> On Feb 9, 3:07 am, Jeremy Nixon <~$!~( )@( )u.defocus.net> wrote:
>> Sosumi <sos... RemoveThis @home.nl> wrote:
>> > You're wrong. I took several pictures and the more MX times, the
>> > sharper
>> > the picture. Less noise is sharper. If you blow the pictures up to 100%
>> > you clearly see normal noise, grain or pixels, while with the MX
>> > pixtures, pixels are hardly visible: it's much smoother.
>>
>> No... you're wrong. It doesn't get sharper, it simply reduces the noise.
>> Less noise isn't "sharper", it's "less noise". You are increasing the
>> signal to noise ratio.
>>
>> > With 5 -10 exposures on one picture the differense is already very
>> > noticeable.
>>
>> Multiple exposure blending reduces noise by a known and mathematically
>> demonstrable amount. Three exposures doubles the signal-to-noise ratio.
>> Nine exposures triples it.
>>
>
> I'd say that four exposures double S/N, etc. No?
>
> Anyway I think we're all wasting our time (unless someone reading this
> thread later finds some of the replies interesting). It looks like the
> OP is just stupidly attacking (and not for the first time).

If you can't win a discussion, you can always start calling names. Real
grown up. Now go get your pacifier and let adult people have a serious
conversation.

--
Sosumi
 >> Stay informed about: Bayer sensor and MX 

"Paul Furman" <paul- RemoveThis @-edgehill.net> schreef in bericht
news:Nwbrj.8782$Ch6.799@newssvr11.news.prodigy.net...
> Thanks Ben for a nice clear explanation. This can be really effective for
> astronomy but that is pushing the limits so far beyond normal photography.
> For astro work they make amazing cameras for astounding prices, extra high
> performance, but I have *never* heard of anyone using those cameras for
> conventional photography because it just doesn't matter. If it mattered,
> you would see someone using those $13,000 cooled high performance
> scientific cameras for advertising diamonds or sports or Hollywood movies
> or something but nobody does.

The part of the Bayer sensor is the practical part.
The part of the multiexposure to 'extract' more resolution is impractical at
least, but theoretically correct.
I'ts a nice thought experiment. (No and for normal people it is totaly
unfeasable).

ben


>
> ben brugman wrote:
>>
>> "Sosumi" <sosumi RemoveThis @home.nl> schreef in bericht
>> news:wNadnSk0HdDS-THanZ2dneKdnZydnZ2d@novis.pt...
>>> The way the Bayer sensor works, it "makes up" color information
>>> depending on the surrounding pixels. But if you do multiple exposures
>>> with exactly the same scene, the picture gets more sharp according to
>>> the amount of exposures.
>>
>> No the picture does not get more sharp. If there is a lot of noise in one
>> normal
>> picture, the definition of the picture get's a littlebit better, but for
>> most normal
>> pictures (in normal light) taking more pictures of the same scene does
>> not make
>> it sharper.
>>
>> In theory small movements of the camera and adjusting for these movements
>> when adding the pictures, will give a better picture and less risc of
>> moire.
>> In theory this method can even make pictures sharper, but then you need
>> a very large amount of the 'same' pictures to get the pictures noticeble
>> sharper.
>>
>>> Much is due to the fact that noise is distributed randomly and hence,
>>> the same place where a "piece" of noise was before, it's over written
>>> with data the next exposure.
>> Multiple pictures will reduce the noice, but with correctly exposed
>> pictures
>> there is not a lot of noise. (Long exposure pictures will benefit from
>> multiple
>> exposure, but not normally exposed pictures).
>>
>>> What I was wondering: do the pixel interpolation always work the same
>>> way? Or is this also slightly random (shifting)? So do you, in fact, get
>>> more information or only less noise? It just seems hard to believe, that
>>> every take of a picture would give exactly (I mean pixel deep peeping)
>>> the same result.
>>>
>>> And also: do all Bayer sensor work exactly the same, or is there a
>>> difference in Nikon, Canon, older, newer models?
>>
>> There are some variations.
>> Most sensors have 2 greens, 1 red and 1 blue for every four cells in a
>> square.
>> There are sensors where the second green is replace by another color.
>> There are sensors which are not RGB, but YMC, but I haven's seen them
>> them lately
>> in camera's.
>>
>> Normal Bayer sensors
>>
>> GRGRGRGR
>> BGBGBGBG
>> GRGRGRGR
>> BGBGBGBG
>>
>> Interpolation which is most simple is that, on each pixel
>>
>> Green pixel (position).
>> Green = G (from the pixel)
>> Red= (Rl+Rr)/2 from the left and the right
>> Bleu = (Bu+Bd)/2 from the up and down bleu.
>>
>> Red pixel (position).
>> Green = (Gl+Gr+Gu+Gd)/4
>> Red = R (from the pixel)
>> Bleu = (B+B+B+B)/4 from the 4 corners of R
>>
>> Bleu pixel (position).
>> Green = (Gl+Gr+Gu+Gd)/4
>> Red = (R+R+R+R) /4 from the 4 corners of B
>> Bleu = B (from the pixel)
>>
>> This is without sharpening or any other fancy stuf.
>> (In general sharpening subtracts a little bit of pixels laying further
>> away).
>>
>> When using multiple exposure with shifted pixels, something similar is
>> done,
>> with far smaller pixels, where the 'large' pixels are shifted over the
>> small pixels.
>> Using sharpening this will result in a slightly sharper picture.
>>
>> As you can see the Red and Bleu pixels (positions) get the information of
>> the
>> Bleu and Red colors from quite some distance.
>> The resolution for red only or bleu only is significant less than for
>> black and white.
 >> Stay informed about: Bayer sensor and MX