# US 9,883,122 B2 · Event-based down sampling > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,883,122 B2 - Document ID: US9883122B2 - Status: Granted - Kind: B2 - Application number: 14/853,991 - Filed: 2015-09-14 - Published: 2016-03-17 - Granted: 2018-01-30 - Earliest claimed: 2014-09-16 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Venkat Rangan; William Howard Constable; Xin Wang; Manu Rastogi - Web page: https://patentgrep.com/patent/US9883122B2 ## CPC - G06V 20/52: Surveillance or monitoring of activities, e.g. for recognising suspicious objects (recognising microscopic objects G06V20/69) - G06V 30/2504: {Coarse or fine approaches, e.g. resolution of ambiguities or multiscale approaches} - H04N 25/47: Image sensors with pixel address output; Event-driven image sensors; Selection of pixels to be read out based on image data - H04N 25/76: Addressed sensors, e.g. MOS or CMOS sensors - G06F 17/10: Complex mathematical operations {(function generation by table look-up G06F1/03; evaluation of elementary functions by calculation G06F7/544)} - G06N 3/063: using electronic means - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS ## Abstract A method of event-based down sampling includes receiving multiple sensor events corresponding to addresses and time stamps. The method further includes spatially down sampling the addresses based on the time stamps and the addresses. The method may also include updating a pixel value for each of the multiple sensor events based on the down sampling. ## Claims ### Claim 1 A method of event-based down sampling, comprising: receiving a plurality of sensor events, each sensor event of the plurality of sensor events corresponding to an address and a time stamp; selecting a first sensor event from the plurality of sensor events; determining that a second sensor event from the plurality of sensor events is received within a predetermined time of a time stamp corresponding to the first sensor event; and spatially down sampling the first sensor event and the second sensor event based on the second sensor event being received within the predetermined time. ### Claim 2 (depends on 1) The method of claim 1, in which spatially down sampling comprises mapping an original coordinate system to a down sampled coordinate system. ### Claim 3 (depends on 2) The method of claim 2, in which spatially down sampling comprises dropping at least one least significant bit of the addresses. ### Claim 4 (depends on 1) The method of claim 1, further comprising down sampling in time by computing a time stamp value as a function of time stamps within packets being down sampled. ### Claim 5 (depends on 1) The method of claim 1, further comprising down sampling in time by selecting a specific sensor event corresponding with a specific time stamp when a plurality of sensor events with a common address have different time stamps, within a predetermined time span. ### Claim 6 (depends on 1) The method of claim 1, further comprising: determining whether the first sensor event and the second sensor event are spatially down sampled; updating a pixel value corresponding to each of the plurality of sensor events when the first sensor event and the second sensor event are spatially down sampled; and maintaining the pixel value corresponding to each of the plurality of sensor events when the first sensor event and the second sensor event are not spatially down sampled. ### Claim 7 An apparatus for event-based down sampling, comprising: means for receiving a plurality of sensor events, each sensor event of the plurality of sensor events corresponding to an address and a time stamp; means for selecting a first sensor event from the plurality of sensor events; means for determining that a second sensor event from the plurality of sensor events is received within a predetermined time of a time stamp corresponding to the first sensor event; and means for spatially down sampling the first sensor event and the second sensor event based on the second sensor event being received within the predetermined time. ### Claim 8 (depends on 7) The apparatus of claim 7, in which the means for spatially down sampling comprises means for mapping an original coordinate system to a down sampled coordinate system. ### Claim 9 (depends on 8) The apparatus of claim 8, in which the means for spatially down sampling comprises means for dropping at least one least significant bit of the addresses. ### Claim 10 (depends on 7) The apparatus of claim 7, further comprising means for down sampling in time by computing a time stamp value as a function of time stamps within packets being down sampled. ### Claim 11 (depends on 7) The apparatus of claim 7, further comprising means for down sampling in time by selecting a specific sensor event corresponding with a specific time stamp when a plurality of sensor events with a common address have different time stamps, within a predetermined time span. ### Claim 12 (depends on 7) The apparatus of claim 7, further comprising: means for determining whether the first sensor event and the second sensor event are spatially down sampled; means for updating a pixel value corresponding to each of the plurality of sensor events when the first sensor event and the second sensor event are spatially down sampled; and means for maintaining the pixel value corresponding to each of the plurality of sensor events when the first sensor event and the second sensor event are not spatially down sampled. ### Claim 13 An apparatus for event-based down sampling, comprising: a memory unit; and at least one processor coupled to the memory unit, the at least one processor being configured: to receive a plurality of sensor events, each sensor event of the plurality of sensor events corresponding to an address and a time stamp; to select a first sensor event from the plurality of sensor events; to determine that a second sensor event from the plurality of sensor events is received within a predetermined time of a time stamp corresponding to the first sensor event; and to spatially down sample the first sensor event and the second sensor event based on the second sensor event being received within the predetermined time. ### Claim 14 (depends on 13) The apparatus of claim 13, in which the at least one processor is further configured to spatially down sample by mapping an original coordinate system to a down sampled coordinate system. ### Claim 15 (depends on 14) The apparatus of claim 14, in which the at least one processor is further configured to spatially down sample by dropping at least one least significant bit of the addresses. ### Claim 16 (depends on 13) The apparatus of claim 13, in which the at least one processor is further configured to down sample in time by computing a time stamp value as a function of time stamps within packets being down sampled. ### Claim 17 (depends on 13) The apparatus of claim 13, in which the at least one processor is further configured to down sample in time by selecting a specific sensor event corresponding with a specific time stamp when a plurality of sensor events with a common address have different time stamps, within a predetermined time span. ### Claim 18 (depends on 13) The apparatus of claim 13, in which the at least one processor is further configured: to determine whether the first sensor event and the second sensor event are spatially down sampled; to update a pixel value corresponding to each of the plurality of sensor events when the first sensor event and the second sensor event are spatially down sampled; and to maintain the pixel value corresponding to each of the plurality of sensor events when the first sensor event and the second sensor event are not spatially down sampled. ### Claim 19 A non-transitory computer-readable medium having program code recorded thereon, the program code for event-based down sampling being executed by a processor and comprising: program code to receive a plurality of sensor events, each sensor event of the plurality of sensor events corresponding to an address and a time stamp; program code to select a first sensor event from the plurality of sensor events; program code to determine that a second sensor event from the plurality of sensor events is received within a predetermined time of a time stamp corresponding to the first sensor event; and program code to spatially down sample the first sensor event and the second sensor event based on the second sensor event being received within the predetermined time. ### Claim 20 (depends on 19) The computer-readable medium of claim 19, in which the program code to spatially down sample comprises program code to map an original coordinate system to a down sampled coordinate system. ### Claim 21 (depends on 20) The computer-readable medium of claim 20, in which the program code to spatially down sample comprises program code to drop at least one least significant bit of the addresses. ### Claim 22 (depends on 19) The computer-readable medium of claim 19, further comprising program code to down sample in time by computing a time stamp value as a function of time stamps within packets being down sampled. ### Claim 23 (depends on 19) The computer-readable medium of claim 19, further comprising program code to down sample in time by selecting a specific sensor event corresponding with a specific time stamp when a plurality of sensor events with a common address have different time stamps, within a predetermined time span. ### Claim 24 (depends on 19) The computer-readable medium of claim 19, further comprising: program code to determine whether the first sensor event and the second sensor event are spatially down sampled; program code to update a pixel value corresponding to each of the plurality of sensor events when the first sensor event and the second sensor event are spatially down sampled; and program code to maintain the pixel value corresponding to each of the plurality of sensor events when the first sensor event and the second sensor event are not spatially down sampled.