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New Sensor Has Real Per-Pixel RGB Sensitivity
jonr writes: "Well, the holy grail of digital photography is finally found. A company named Foveon have developed a sensor that captures RGB colours on each pixel. So what you say? Well, for the past 30 years (or since the CCD was invented) we have been using CCD with with red, green & blue sensors (or cyan/magneta/yellow) and then used software to figure out the real colour. But Foveon is the first company to deliver RGB-in-each-pixel sensor.
For those of you who are not into digital imaging, this makes a lot of difference, it's would be just as revelutionary if somebody would make a flatscreen with a real colour pixels, instead of the RGB dots. dpreview.com has the scoop.
(No, it won't mean the death of film, but I suspect we'll see dramatic improvement in quality)."
That is exactly right.
No, it's almost entirely wrong. The most common configuration for a digital camera uses what's known as a Bayer filter pattern for discerning color. Each pixel will only sense red, green, or blue (there are as many green as there are red and blue combined), and it will use neighboring pixels to extrapolate the true color. While it's true that some of the pixels are lost from the stated resolution (stated pixels actually refers to photosites), it's only about 200,000 in a 2mp CCD.
Yes. At the University of Heidelberg, Germany, Physicists have developed a log-response CCD chip (covering 6 decades of intensity). They want to use it as the frontend sensor for their "tactile vision substitution system" (a machine enabling blind people to "see" with their fingers). The Log response is achieved by operating the sensor transistors in their non-linear range (very crude description, it's been a long time ago since I attended a talk about that project). Links to publications can be found following the above link.
This thing could also make one heck of a nice nightvision system, if used properly... so we could all have nice color pictures at night, just like the military folks have had for a long time. (Green screens are just for the media to consume).
--Mike--
There are a couple of problems with logarithmic sensitivities in electronics- the little potential wells fill up too quickly. Make them too deep and they lose the low level light, make them too shallow and the electrons spill out.
Conventional AgX can capture around 14 stops of light (thats 2^14) - conventional paper can handle 8 stops or so... a typical scene has 2^11, give or take. Depends on the scene and the subject- obviously a shot of a barn with the door open in broad daylight is going to have a bit more range than a shot inside in a white room with light bouncing everywhere.
So, what you really want, is to have the SOFTWARE be cognizant of higher bitdepth images. When you have 8 bits to capture a 10 bit scene, information is lost. So you throw some out... and you end up with muddled highlights and muddled shadows, and something in the middle that looks decent.
Believe it or not, but alot of companies have spent alot of money trying to figure out the correct 'mental' representation of a greyscale- not even including colour. I'm partial to Kodak (I work there, but these views are mine).
I've worked with extended bit depth images quite a bit and know that there is none (read, big fat ZERO) ms support for anything over 8 bits.... in fact, ImageViewer simply locks up and crashes. So any sort of solution that gives you extended tonal rendering are going to have to be custom solutions... and that probably won't sit well with the average person- "what do you mean i have to process my pictures before I can view them?!?!? I'll just go buy another camera" etc etc. Even if the benefits are enormous, there is the simplicity factor that drives it.
I personally am interested in this sensor, but there seems to be the wrong website linked... which worries me...
Had you read the info on the site, you would know they aren't taking specifically about increasing the resolution.
They are increasing the amount of light captured per element.
Succinct overview: (Let's say we have a camera with 16 pixel (4x4 matrix)
In a typical mosaic CCD pixels would be the following:
gbgr
rgbg
grgb
bgrg
That's 8 green pixels, 4 red and 4 blue.
Thus 50% green, 25% red and 25% blue.
Now, after the image is captured, the camera has to do some serious image manipulation to translate the average color per pixel into an RGB value. Depending on the "correctness" of the algorithm used, you'll get all sorts of fun... low light noise, color shifts, purple fringing, moire patterns.. etc. and all that processing chews cpu time and battery life, and slows down the speed from picture to picture.
(Yes, some cameras have higher speed processors... just means yet more battery drain)
In their new method of capturing the layout is as follows:
aaaa
aaaa
aaaa
aaaa
In this case, all 16 pixels capture red green and blue. This means NO processing to be done to calculate color per pixel.
It also means a 2x increase in the amount of green light captured. And a 4x increase in the amount of both red and blue light captured.
More light being captured = more light and shadow detail.
Not having to process (interpolate) pixel colors = no more fringing, moire or other funkiness.
Now, that doesn't change the fact that digital sensors rely on converting a given set of photons into an electrical charge, and that's tough work... but having more light detected at each photo element is going to give you a LOT more light and shadow definition.
But, I digrees. I don't know of anyone pioneering new ways of doing ADC for photo elements.