Saturday, April 01, 2006

Advis - New CMOS Imager Company

Not really very recent news, but Dr. Mark F. Bocko from Rochester University started a new image sensor company: ADVantatge Imaging Systems Inc. - ADVIS.

The company pitches wide dynamic range and low-power of their sensors:

"ADVIS’s Direct Photodigital Conversion (DPC) technology turns photons into a single bit digital stream at each pixel site to create the highest dynamic range and lowest power image sensor in the world."

"ADVIS DPC technology has demonstrated a dynamic range of 100dB at a power consumption of 0.88 nanoWatt/per pixel (30 frames per second). This is one-thousandth the power required by typical CCD’s and less than one percent of the power used by typical CMOS Active Pixel Sensors (APS)."

The basic building block is a distributed sigma-delta convertor. On the surface it looks very similar to Amain's approach which failed to get the market acceptance.
Another product is image sensor with integrated image compression engine - it's supposed to be very low power too.

Below is Eric Fossum's opinion on ADVIS technology (link):
"I have some information about this sensor. I don't think it has any advantages over other technology.
1. Pixel-level sigma-delta. Every reset (delta) adds kTC noise.
2. In low light, not even clear how a single pulse will be generated.
3. No one has seen a low light level image from the prototype sensor that I know, incl. potential investors.
4. Unless the sampling rate is high, and threshold low, this sensor is going to see large lag under low light conditions.
5. You cannot average out shot noise. Yikes!
6. Decimation filter power and chip area requirements are significant.
7. You need a frame buffer somewhere to implement the decimation filter.
8. Most power in sensors is due to the readout. ADVIS conveniently ignores the readout power and pad driver power. They also don't include the decimation filter or frame buffer power.
9. There are already many viable ways of doing high dynamic range imaging. The problem is not the technology, it is in the market.
10. It seems to me that the advis technology was developed by someone who doesnt understand image sensors very well. Look at his track record in imaging. Zero thus far. That would be consistent with the claims being made.
Hate to be brutal, but that is the way I see it.

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