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Re: [OM] Pixel Wars - The Next Generation

Subject: Re: [OM] Pixel Wars - The Next Generation
From: Fernando Gonzalez Gentile <fgonzalezgentile@xxxxxxxxx>
Date: Thu, 31 Dec 2009 21:16:30 -0200
Cc: Fernando Gonzalez Gentile <fgnzalez@xxxxxxxxxxx>
Tim, excellent post !!

During 1977 - 78 I subscribed to Scientific American, I may have had
that article 'though I lost many of the monthly issues ....emmm, only
six remain in my library. During those years I made an attempt to go
to the States to study biochemistry. I didn't win the grant, long
story.
I do have some serious works on perception, just yesterday I read one
here, about tinnitus (I'm very worried about my new audio monitors ...
:-) ) 
<http://www.pnas.org/content/early/2009/12/15/0911268107.full.pdf+html?sid=7e5a21bd-942e-4e1c-9582-5b924ba5a791>
This also relates to an old post of Chuck regarding hearing loss.

Cheers,

Fernando

2009/12/31 Tim Hughes <timhughes@xxxxxxxx>:
> Ken, a couple of comments:
>
> People interested in the human perception issues of color, might enjoy 
>  reading the long popular article by Edwin Land (Polaroid fame), which 
> appeared in Scientific American.(Edwin H. Land, "The Retinex Theory of Color 
> Vision," Scientific American, Vol. 237, No. 6, pp. 108-128, December 1977.)
> His theory of color perception is termed "Retinex theory".
> here are a few related simplified links:
> http://people.msoe.edu/~taylor/eisl/land.htm
> http://www.wendycarlos.com/colorvis/color.html
> http://en.wikipedia.org/wiki/Color_constancy
> http://www.wendycarlos.com/colorvis/retinex.html
> http://color.psych.upenn.edu/brainard/papers/retinex.pdf
> http://www.rowland.harvard.edu/organization/land/theory.php
>
> One interesting thing is the brain can do a surprisingly good job of 
> reconstructing a full set of colors from a display screen, even if only 2 
> types of carefully chosen color pixels are used, in place of 3.
>
> There are so many variations on the more than tri-color camera sensor matrix, 
> which have been suggested and patented. A very interesting variation but for 
> color screen display use, is using RGBW.  (W = white)
>
> Some of the Fuji and other >3 color sensors land up with non-rectangular 
> pixel layout. This can mean the resolution is highest on a diagonal not 
> horizontal and vertical axis. This is a slight disadvantage apparently, as
> we percieve better sharpness, if the resolution is highest on the horizontal.
>
> A dificulty with the Foveon sensor, is not just their execution and having to 
> have a different dematrixing software/hardware, which is more expensive 
> because of lower volumes,but the RGB absorbtion curves have very broad 
> overlap with one another, making it much harder,to seperate the colors 
> accurately. This tends to magnify the noise despite the inherent advantage of 
> not throwing away more than 2/3 of photons, as in the normal 2D filter 
> sensor. Using another type of vertical filter in a stackerd sensor, as you 
> suggest, could theoretically retain this photon (noise) advantage, if it were 
> practical to make.
>
>  The human eye is similar to the Foveon sensor in that the absorbtion 
> spectrum of the  different Rhodpsins in the eye are very similar, with huge 
> overlap making the brains job much tougher, in sorting out the real colors. 
> This is an example of why the eye is a rather imperfect, but highly optimised 
> design, despite what old creationists used to claim about godly design 
> perfection in the eye!
>
> see curves here: http://www.wendycarlos.com/colorvis/conecurv.jpg
> and discussion of opsins here : http://en.wikipedia.org/wiki/Rhodopsin
>
> Tim Hughes
>
> --- On Mon, 11/16/09, Ken Norton <ken@xxxxxxxxxxx> wrote:
>
>> From: Ken Norton <ken@xxxxxxxxxxx>
>> Subject: [OM] Pixel Wars - The Next Generation
>> To: "Olympus Camera Discussion" <olympus@xxxxxxxxxxxxxxxxx>
>> Date: Monday, November 16, 2009, 5:09 AM
>> A shameless plug alert.
>>
>> We have a new article posted on Zone-10 which is predicting
>> future
>> development of sensors in our digital cameras. I'm sure a
>> few things in it
>> may seem a little futuristic, but isn't that the purpose of
>> a prediction
>> article? However, each and every technology mentioned in
>> the article is
>> found through patent searches and some slick detective
>> work.
>>
>> http://zone-10.com/cmsm/index.php?option=com_content&task=view&id=461&Itemid=1
>>
>> <http://zone-10.com/cmsm/index.php?option=com_content&task=view&id=461&Itemid=1>
>> AG
>> --
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>>
> --
> _________________________________________________________________
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>



-- 
Dr.Fernando González Gentile
Av.L.P.Ponce 1526B
11600 Montevideo, Uruguay.
Phone: +598 2 7084858
Fax: +598 2 7087396
<fgnzalez@xxxxxxxxxxxxx>
-- 
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