Unbounded High Dynamic Range Photography Using a Modulo Camera

The actual headline of the article is actually more informative and less misleading than the subhead:

"Unbounded High Dynamic Range Photography Using a Modulo Camera"

In photographer's terms, they're referring to ending blown highlights (caused by filling the wells in a sensel) not saturated images (caused by exaggerating color data).

There's a school of photography that basically lives and dies by over-saturating images (e.g. http://kenrockwell.com ) and they'd likely have a cow over the headline, but understand and be totally onboard for the actual goal.

Depending on how quickly the well can reset and how many times resets can be counted this will either be better or worse than simply improving existing approaches. The state of the art in full frame sensors is just under 15-bits of dynamic range. So to equal it an 8-bit sensor would need to be able to count resets at least 128 times AND be able to do this in 1/8000 of a second, at the same sensel density and efficiency! Don't hold your breath.

http://www.dxomark.com/Cameras/Nikon/D810

(I'd also suggest that trends towards using multiple sensors to assemble high resolution images will easily blow this away since they can use high- and low- sensitivity sensors to synthesize more dynamic range and resolution. Also see recent Olympus patents to capture polarization data at the same time.)

BTW: assuming they can do this stuff, they presumably can read the sensor pretty darn fast — so they should be able to eliminate image "tearing" in digital video and the need for mechanical shutters altogether. That's probably a bigger issue than dynamic range.

I suspect that clearing a well in < 1/10,000,000 of a second (which would only lose 10% of the photon detection time during a 1/8000s exposure) is going to be tough. Assuming 25% of the sensel real estate needs to be sacrificed to the modulo circuitry, that's a loss of 32.5% of photon data which is about the same loss as for pellicle mirrors (as seen in Sony's pretty unsuccessful SLT cameras) for a feature that won't be much use in many situations.

What would normally have been indistinguishable blacks are pushed into the midtones and you get a flat, grainy image. It just looks like garbage because noise gets out of hand and you lose all your color depth, but there's more dynamic range there in the sense of there being more stops of light crammed onto the final image.

There is a physical limit of the camera or the film where you cannot actually squeeze any more accuracy out of the ADC, but standard conditions are nowhere near that limit.

I was thinking of a prism (new word: pellicle mirror) like this one :

http://static1.squarespace.com/static/54ca877ce4b014ea90e14b...

Except I don't need the deconvolutional prism. I can handle that in software easily with a X or Y matrix flip. And I assume we are using the same CCD module for both areas; given that, I can sum the contrast between the pixels and calculate the min and max, as well as can calculate the HDR image from both sources.

Calibration would be easy to handle, using a checkerboard to link the CCDs to each other (assume aligning errors will happen).

I also see no reason why the pellicles wouldn't be kept clean. The same goes for the CCDs as well. I'd embed them in a dark acrylic box and try to seal them as best as can be.