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Panasonic patents sensor with white pixels to eliminate the IR cut filter

 
 
RichA
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      04-10-2012
Good idea I guess.

http://www.freepatentsonline.com/EP2434761A1.html
 
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David J Taylor
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      04-10-2012
"RichA" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Good idea I guess.
>
> http://www.freepatentsonline.com/EP2434761A1.html


A filter is still needed to stop the "white" pixels from having a response
into the IR, so those pixels (at least) still need the filter, although if
they have well-designed colour filters, only the "white" pixels will need
a filter. But surely you could do that with well-designed RGB filters?

It's about improving sensitivity.

Sounds remarkably like the CMY filters which have been done before.

David

 
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nospam
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      04-10-2012
In article <jm1a05$50d$(E-Mail Removed)>, David J Taylor
<(E-Mail Removed)> wrote:

> > http://www.freepatentsonline.com/EP2434761A1.html

>
> A filter is still needed to stop the "white" pixels from having a response
> into the IR, so those pixels (at least) still need the filter, although if
> they have well-designed colour filters, only the "white" pixels will need
> a filter. But surely you could do that with well-designed RGB filters?


a quick skim of the patent says that infrared is removed mathematically.

> It's about improving sensitivity.


it's about removing the infrared cut filter, which they claim impacts
sensitivity. i don't think it's as big of an issue as they suggest.

> Sounds remarkably like the CMY filters which have been done before.


thats what the w-r, w-g and w-b pixels are.
 
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David J Taylor
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      04-10-2012
"nospam" <(E-Mail Removed)> wrote in message
news:100420120904128840%(E-Mail Removed)...
> In article <jm1a05$50d$(E-Mail Removed)>, David J Taylor
> <(E-Mail Removed)> wrote:
>
>> > http://www.freepatentsonline.com/EP2434761A1.html

>>
>> A filter is still needed to stop the "white" pixels from having a
>> response
>> into the IR, so those pixels (at least) still need the filter, although
>> if
>> they have well-designed colour filters, only the "white" pixels will
>> need
>> a filter. But surely you could do that with well-designed RGB filters?

>
> a quick skim of the patent says that infrared is removed mathematically.
>
>> It's about improving sensitivity.

>
> it's about removing the infrared cut filter, which they claim impacts
> sensitivity. i don't think it's as big of an issue as they suggest.
>
>> Sounds remarkably like the CMY filters which have been done before.

>
> thats what the w-r, w-g and w-b pixels are.


Yes, it's been done before. The problem with removing IR mathematically
could be that with the larger number of photons incident on the sensor,
the signal to noise ratio would be degraded. I agree that it's no a major
issue, and would be surprised if anything significant results. Having
said that, I would like to see what response a current IR cut-off filter
actually has, to know what its impact on sensitivity actually is.
Judgment reserved.

David

 
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RichA
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      04-10-2012
On Apr 10, 11:07*am, "David J Taylor" <david-
(E-Mail Removed)> wrote:
> "nospam" <(E-Mail Removed)> wrote in message
>
> news:100420120904128840%(E-Mail Removed)...
>
>
>
>
>
>
>
>
>
> > In article <jm1a05$(E-Mail Removed)>, David J Taylor
> > <(E-Mail Removed)> wrote:

>
> >> >http://www.freepatentsonline.com/EP2434761A1.html

>
> >> A filter is still needed to stop the "white" pixels from having a
> >> response
> >> into the IR, so those pixels (at least) still need the filter, although
> >> if
> >> they have well-designed colour filters, only the "white" pixels will
> >> need
> >> a filter. *But surely you could do that with well-designed RGB filters?

>
> > a quick skim of the patent says that infrared is removed mathematically..

>
> >> It's about improving sensitivity.

>
> > it's about removing the infrared cut filter, which they claim impacts
> > sensitivity. i don't think it's as big of an issue as they suggest.

>
> >> Sounds remarkably like the CMY filters which have been done before.

>
> > thats what the w-r, w-g and w-b pixels are.

>
> Yes, it's been done before. *The problem with removing IR mathematically
> could be that with the larger number of photons incident on the sensor,
> the signal to noise ratio would be degraded. *I agree that it's no a major
> issue, and would be surprised if anything significant results. *Having
> said that, I would like to see what response a current IR cut-off filter
> actually has, to know what its impact on sensitivity actually is.
> Judgment reserved.
>
> David


According to Leica and a few prostitutes supporting them, no impact
which is ridiculous. They said this when the M8 flaw was discovered
and they had to slap those cyan filters on the front of their
cameras. A hot mirror filter (one that rejects IR) won't work, I've
tried it.
 
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nospam
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      04-10-2012
In article
<(E-Mail Removed)>,
RichA <(E-Mail Removed)> wrote:

> They said this when the M8 flaw was discovered
> and they had to slap those cyan filters on the front of their
> cameras. A hot mirror filter (one that rejects IR) won't work, I've
> tried it.


their fix was a hot mirror filter, not cyan filter.
 
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RichA
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      04-11-2012
On Apr 10, 4:52*pm, nospam <(E-Mail Removed)> wrote:
> In article
> <(E-Mail Removed)>,
>
> RichA <(E-Mail Removed)> wrote:
> > They said this when the M8 flaw was discovered
> > and they had to slap those cyan filters on the front of their
> > cameras. *A hot mirror filter (one that rejects IR) won't work, I've
> > tried it.

>
> their fix was a hot mirror filter, not cyan filter.


Interesting because I have a Tiffen hot mirror filter for IR rejection
and I've tried it on cameras where I've removed the IR rejection
filter from the front of the sensor and it doesn't work the same way.
The IR rejection filter is cyan, the hot filters appear clear face-on
(at least the one I have and one I saw on a Sigma DSLR) have and red
if you tilt them, the red being the dielectric rejection coating.
 
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