[HN Gopher] Photonic Chip Performs Image Recognition at the Spee...
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       Photonic Chip Performs Image Recognition at the Speed of Light
        
       Author : em3rgent0rdr
       Score  : 74 points
       Date   : 2022-06-07 13:45 UTC (9 hours ago)
        
 (HTM) web link (spectrum.ieee.org)
 (TXT) w3m dump (spectrum.ieee.org)
        
       | coffinbirth wrote:
       | Looks like a "modern version" of the numa-rete, developed by Paul
       | Weston at Heinz von Foersters Biological Computer Laboratory
       | (BCL):
       | https://distributedmuseum.illinois.edu/exhibit/biological_co...
        
       | JoeAltmaier wrote:
       | Not sure how image recognition rates (frames/sec?) translate into
       | meters/sec.
        
       | amelius wrote:
       | Are the network weights hardcoded (like a ROM), or is the network
       | programmable?
        
         | wgd wrote:
         | The article implies that the weights are programmable, but the
         | overall shape is fixed.
        
       | gene-h wrote:
       | Now make it able to work directly on visible light or at least
       | the output of an image intensifier and you can make some pretty
       | fast killer drones.
        
         | Gravityloss wrote:
         | One could do preprocessing like edge detection with this, like
         | happens in biological retinas. Then a lot less data needs to be
         | processed down the line.
        
       | Eddy_Viscosity2 wrote:
       | "5-by-6 pixel array"
       | 
       | These are not exactly high res images.
        
         | wgd wrote:
         | Equally important: "nine neurons". This is not a deep circuit.
         | 
         | When we say that a CPU is running at some frequency that's
         | essentially the speed at which a signal propagates through _all
         | the gates_ of its slowest pipeline stage, and the individual
         | gates have a transition frequency an order of magnitude higher.
         | 
         | So if a CPU is running at 4GHz, it completes a clock cycle in
         | 0.25ns (250ps), but that means that individual transistors must
         | have latencies <=0.025ns (25ps). If you built a tiny little
         | 9-neuron single-layer network out of those transistors then the
         | network's latency would be around the single-gate latency and
         | it would appear to be 20x better than this photonic setup, and
         | even if those 9 neurons were laid out sequentially it would
         | outperform this photonic chip by 2x.
         | 
         | Now granted, that's comparing the performance of a mature IC
         | process using equipment that cost billions of dollars to set
         | up, to something that was built in a university lab on a
         | substantially smaller budget, so direct performance comparisons
         | aren't exactly fair in that sense. But it's also misleading to
         | take a direct hardware implementation of an itty bitty neural
         | network and handwave away the very real issues with scaling
         | such an approach.
        
           | causi wrote:
           | Yes, this is seriously blurring the line between image
           | recognition and a bandpass filter. There doesn't seem to be
           | anything in the way of actual computation going on until the
           | step where the results are read.
        
         | etskinner wrote:
         | Once a proof-of-concept exists, scaling it up is conceivable.
         | Computers used to have kilobytes of RAM, now some have
         | terabytes. Digital cameras used to have sub-megapixel
         | resolution, now some are measured in gigapixels.
        
           | mensetmanusman wrote:
           | "1 pixel should be enough for everyone"
        
             | touisteur wrote:
             | It could! https://opg.optica.org/oe/fulltext.cfm?uri=oe-28-
             | 19-28190&id...
        
             | mhh__ wrote:
             | Most zoom calls are fine with 0 thank you very much
        
           | daniel-cussen wrote:
           | Mmm...but scaling up is not the same in photonics as it is in
           | digital. Everyone thinks of scaling in terms of digital, like
           | Alan Turing, von Neumann, and later Moore talked about, if
           | you have an amplifier you can amplify it with another
           | amplifier, so as long as it's totally digital the signals can
           | be manipulated at arbitrarily small scales. Not true for
           | analog or photons or quantum, there's weird caveats and
           | they're not well researched, this scaling works only for
           | digital.
        
             | haswell wrote:
             | Sure, our existing understanding and models for scale may
             | not directly apply.
             | 
             | That doesn't limit the creation of new models and new
             | understanding. Just because scaling might be different
             | doesn't mean it's impossible.
             | 
             | Our existing models did not exist at some point in the
             | past.
        
       | orlp wrote:
       | For a somewhat related topic (analog image recognition), for
       | those interested, I can highly recommend this video:
       | https://www.youtube.com/watch?v=Y9FZ4igNxNA
        
       | superb-owl wrote:
       | I'm really excited by the idea of using analog computing for AI,
       | and the advent of analog chips. Anyone know if there's a cloud
       | provider offering hourly access to analog compute?
       | 
       | As an aside, I recently learned of https://lightmatter.co/, a
       | photonic chip manufacturer
        
       | nonrandomstring wrote:
       | Less than a single clock cycle (0.1 ns) of a fast conventional
       | processor? This feels like the difference between
       | electromechanical computing and transistors (skipping vacuum
       | tubes entirely). These moments in life I hoped for as a kid, when
       | you realise there's a step change between technologies you are
       | familiar with and what's coming next are exhilarating and
       | worrying. The downside is that everything we've created to this
       | point, including all the bad applications, will be magnified by
       | the same factor as the good things. Time to get our house in
       | order.
        
         | travisathougies wrote:
         | There are several companies doing photonic computing (some with
         | commercially available or soon-to-be-available chips).
         | Unfortunately, it's currently all for naught, as existing
         | available silicon hardware accelerators can currently do the
         | computation faster than anyone can stream the data into the
         | chip. The more interesting problem is data movement, as usual.
        
           | nonrandomstring wrote:
           | I guess this bodes the end of the copper PCB, except for
           | power supplies.
        
             | travisathougies wrote:
             | I'm going to guess most electronics is not going to be
             | super high-speed. Sort of like how fiber optic was once the
             | realm of only large businesses, then small businesses, and
             | now is commonly available at home (although nowhere near
             | 100% adoption). I think the copper PCB will eventually go
             | away, but not for many decades.
        
           | splittingTimes wrote:
           | I do not understand your remark.
           | 
           | > do the computation faster than anyone can stream the data
           | into the chip. The more interesting problem is data movement,
           | as usual.
           | 
           | Is that not the selling point of integrated photonic
           | circuits? You got photonic chips/components that are
           | connected by photonic waveguides. So essentially photons
           | replace electrons for all intents and purposes and the data
           | moves at close to the speed of light.
        
         | thisiscorrect wrote:
         | 570 ps is 0.57 ns.
        
           | mcronce wrote:
           | Also, 0.1ns would be a single clock cycle at 10GHz
        
       | superb-owl wrote:
       | We know Quantum Computing is more computationally powerful than
       | classical digital computing. But I've always been curious if
       | there's a middleground for non-quantum analog computing - does
       | anyone know of theoretical work here? Could we potentially build
       | a non-quantum analog computer that's more computationally
       | powerful than a digital computer?
        
       | XnoiVeX wrote:
       | Isnt this a year old? https://arxiv.org/abs/2106.11747
        
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       (page generated 2022-06-07 23:02 UTC)