NEW DP QUATTRO is coming!!!!!!!!!!!!!

Started Feb 9, 2014 | Discussions thread
Raist3d Forum Pro • Posts: 37,262
Re: NEW DP QUATTRO is coming!!!!!!!!!!!!!

DMillier wrote:

I'm struggling a bit to figure out how it works.

The old Foveon was simple to understand: 3 layers, 3 photo sites per spatial pixel, each photo site stacked exactly above the other. Equal resolution for all colours, no demosaic artefacts, no colour aliasing. Downsides were noise, funny colour response that needed clever fixing.

Bayer is complicated: twice as many green photo sites, no pixels co-located at the same spatial position, every spatial pixel value having to be computed based on many measurements from surrounding photo sites and lots of clever processing. Quite efficient use of photo sites, unequal colour resolution, low level demosaic artefacts, low noise, high dynamic range.

This new Foveon is unique. 20MP in the top layer, only 5MP in the second and third layers. That a big colour channel difference. How are they going to overcome that?

You have to interpolate. But seems to me the interpolation would be easier than Bayer.

The only similarity with old Foveon seems to be silicon filtering (which was the bad bit about Foveon!).

But you get bigger red/green areas so you can deal with noise better while the blue layer which was more noise controlled at the top gets to do the more detail reading.

It's certainly a compromise as all sensors design are, but a different one. Will be interesting.

What will this means for spatial resolution - will it be somewhat like Bayer where the per pixel average resolution is lower than the spatial pixel count?

For color, yes, though it could give the appearance on average of a lot of detail.

Will an 20MP quattro have less resolution than a 20MP X3 Foveon?

For color and assuming a 20 MP X3 Foveon at ISO 100 shooting in full spectrum light, yes.

What about colour resolution? Is is still going to be equal across all colours?

No, the original Foveon design would have more. However the original Foveon design didn't scale with resolution having quite a bit of noise, in which case, the sensor with less noise may very well pull ahead anyway.

Will foveon fans stop demanding the use of colour resolution charts in future reviews? What about subtle colour gradation, will this be retained? What about artefacts? Will the new quattro layout mean there will demosaic like artefacts?

There are indeed possibilities of color artifacts now.

Can someone walk through how this new architecture actually works? Roland? Anybody?

Just look at the diagram.  The Blue channel has more resolution than the other layers so they use that to drive luminance, but use the all the layers to drive color. This means to go to a 19 MP output file you need to interpolate for color.  This means there will be potential for a different set of artifacts.

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Raist3d/Ricardo (Photographer, software dev.)- I photograph black cats in coal mines at night...
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