# US 2019/0244079 A1 · Identifying mirror symmetry density with delay in spiking neural networks > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0244079 A1 - Document ID: US20190244079A1 - Status: Published application - Kind: A1 - Application number: 16/266,765 - Filed: 2019-02-04 - Published: 2019-08-08 - Earliest claimed: 2018-02-02 - Assignees: The George Washington University - Applicants: The George Washington University - Inventors: Jonathan K. George; Volker J. Sorger - Web page: https://patentgrep.com/patent/US20190244079A1 ## CPC - G06N 3/049: Temporal neural networks, e.g. delay elements, oscillating neurons or pulsed inputs - G06N 3/048: Activation functions - G06N 3/063: using electronic means - G06N 3/0675: {using electro-optical, acousto-optical or opto-electronic means} - G01J 11/00: Measuring the characteristics of individual optical pulses or of optical pulse trains - G06E 3/005: {using electro-optical or opto-electronic means} - G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - G06E: OPTICAL COMPUTING DEVICES (digital storage using optical elements G11C13/04) ## Abstract The ability to rapidly identify symmetry and anti-symmetry is an essential attribute of intelligence. Symmetry perception is a central process in human vision and may be key to human 3D visualization. While previous work in understanding neuron symmetry perception has concentrated on the neuron as an integrator, the invention provides the coincidence detecting property of the spiking neuron can be used to reveal symmetry density in spatial data. A synchronized symmetry-identifying spiking artificial neural network enables layering and feedback in the network. The network of the invention can identify symmetry density between sets of data and present a digital logic implementation demonstrating an 8×8 leaky-integrate-and-fire symmetry detector in a field-programmable gate array. The efficiency of spiking neural networks can be harnessed to rapidly identify symmetry in spatial data with applications in image processing, 3D computer vision, and robotics. ## Claims ### Claim 1 A symmetry detector to detect symmetry of input data, said symmetry detector comprising: a plurality of input nodes, each input node receiving, a discrete data point of the input data and having a spike producer configured to produce spiked data as a threshold of the input data and a delay device configured to delay the produced spiked data and provide delayed output data; and a plurality of output nodes, each output node connected to one or more of the plurality of input nodes, receiving the delayed output data from each of the connected one or more plurality of input nodes, and having a coincidence detector configured to detect symmetry based on delayed output data that is spiked. ### Claim 2 (depends on 1) The symmetry detector of claim 1, said plurality of input nodes and said plurality of output nodes each comprising a neuron. ### Claim 3 (depends on 1) The symmetry detector of claim 1, said coincidence detector comprising a plurality of multipliers each configured to multiply the delayed output data from each of the connected one or more said plurality of input nodes, an accumulator configured to receive and accumulate the multiplied delayed output data and a threshold detector configured to detect a threshold number of spiked data in the accumulated multiplied delayed output data. ### Claim 4 (depends on 1) The symmetry detector of claim 1, wherein the threshold number represents symmetry of input data. ### Claim 5 (depends on 1) The symmetry detector of claim 1, said spike detector comprising a multiplier configured to multiply the input data, an accumulator configured to receive the multiplied input, a threshold detector configured to detect spiked data in the input data and provide the detected spiked input data. ### Claim 6 (depends on 5) The symmetry detector of claim 5, said accumulator having leak configured to adjust the sensitivity of the output node to detecting symmetry. ### Claim 7 (depends on 1) The symmetry detector of claim 1, said delay device comprising a set of clocks, or a delay counter, or a routing delay. ### Claim 8 (depends on 1) The symmetry detector of claim 1, wherein the delay is proportional to a distance between each respective input node and each respective output node, in the data space. ### Claim 9 A symmetry detector to detect symmetry of input data, said symmetry detector comprising: a plurality of input nodes, each input node receiving a discrete data point of the input data and having a spike producer configured to produce spiked data as a threshold of the input data; and a plurality of output nodes, each output node connected to one or more of the plurality of input nodes, receiving the input node output data from each of the one or more connected plurality of input nodes, each output node having a delay device delaying the input node output data to provide a delayed input node output data, and a coincidence detector configured to detect a threshold number of spikes in the delayed input node output data in a given period of time. ### Claim 10 (depends on 9) The symmetry detector of claim 9, said plurality of input nodes and said plurality of output nodes each comprising a neuron. ### Claim 11 (depends on 9) The symmetry detector of claim 9, said coincidence detector comprising an accumulator configured to receive and accumulate the delayed input node output data and a threshold detector coupled to the accumulator configured to identify the threshold number of spikes. ### Claim 12 (depends on 11) The symmetry detector of claim 11, said accumulator having leak configured to adjust the sensitivity of the output node to detecting symmetry. ### Claim 13 (depends on 9) The symmetry detector of claim 9, wherein the threshold number represents symmetry of input data. ### Claim 14 (depends on 9) The symmetry detector of claim 9, said delay device comprising a set of clocks, or a delay counter, or a routing delay. ### Claim 15 A symmetry detector, comprising: a light source providing light data; a planar optical modulator array having a plurality of discrete positions and modulating the light data proportional to input data at the plurality of discrete positions; and an optical detector array having a plurality of optical detectors, each of the plurality of optical detectors aligned with and receiving modulated light data from one of the plurality of discrete positions of said planar optical modulator array. ### Claim 16 (depends on 15) The symmetry detector of claim 15, wherein the light data comprises a light pulse. ### Claim 17 (depends on 15) The symmetry detector of claim 15, wherein said optical modulator array outputs modulated light data at the plurality of discrete positions having input data and blocks light at the plurality of discrete positions having no input data. ### Claim 18 (depends on 15) The symmetry detector of claim 15, further comprising a gap between said optical modulator array and said optical detector array, said gap providing free space delay of the modulated light data. ### Claim 19 (depends on 18) The symmetry detector of claim 18, wherein delayed modulated light data arriving substantially simultaneously at said optical detectors will surpass a noise floor of the optical detector and will be detected, and delayed modulated light data not arriving substantially simultaneously at said optical detectors will not surpass the noise floor of the optical detector and will not be detected, to detect symmetry of input data at said optical detector array.