[ml] [Noisebridge-discuss] Technical question: Directionally sensitive photosensors

Mike Schachter mschachter at eigenminds.com
Tue Jun 11 16:34:38 UTC 2013


Also cc'ing this discussion to the neuro and ML lists, there are might be
people there that could help with the problem.

 mike



On Tue, Jun 11, 2013 at 9:25 AM, Mike Schachter
<mschachter at eigenminds.com>wrote:

> I suppose the basic idea is to create a chain of integrate-and-fire
> neurons.
>
> Referring to the attached diagram, each neuron gets input from it's own
> photosensor, and from the neuron to the left of it. You will also have to
> make it so that the signal from the photosensor to neuron *decreases* as
> you move right on the chain.
>
> The general idea is that movement to the right makes each neuron spike,
> which sends a spike to the neighboring neuron. If the inputs are timed
> right (which is probably the most tricky part), each successive neuron will
> spike more and send more input to it's neighbors. The last neuron, the
> readout neuron, will spike the most. You can look at the spike rate of the
> last neuron, and if it's high enough, then you declare movement to the
> right. The number of spikes of the last neuron could even be related to the
> velocity of the movement.
>
> Movement to the left shouldn't elicit a single spike from the readout
> neuron.
>
> Another option might be to build a Reichardt correlator:
>
> http://people.csail.mit.edu/rondror/Ronfiles/Research/reichardt.htm
>
> mike
>
>
>
> On Mon, Jun 10, 2013 at 11:46 PM, Christoph Maier <
> cm.hardware.software.elsewhere at gmail.com> wrote:
>
>> On Mon, Jun 10, 2013 at 5:49 PM, Mike Schachter
>> <mschachter at eigenminds.com> wrote:
>> > Oh ok! Well I'd be happy to help Chris with code to do
>> directional-selection
>> > given data from an array of photo-sensitive inputs if that would be
>> useful.
>> >
>> >  mike
>> >
>> >
>> >
>> > On Mon, Jun 10, 2013 at 5:20 PM, Norman <pryankster at gmail.com> wrote:
>> >>
>> >> Mike, that is exactly how a phased array works.
>> >>
>> >> Norman
>> >>
>> >>
>> >> On 6/10/2013 5:07 PM, Mike Schachter wrote:
>> >>
>> >> Can you just get an array of non-directional photosensors and do the
>> >> direction-selectivity computationally on an arduino or something?
>> >>
>> >>  mike
>>
>> Great!
>> Just tell me how to put code into this kind of computer ...
>> http://pony.noisebridge.net/~cmaier/neuromorphic/BIL2011/html/img10.html
>>
>
>
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