# US 11,906,670 B2 · Interference mitigation for light detection and ranging > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,670 B2 - Document ID: US11906670B2 - Status: Granted - Kind: B2 - Application number: 16/841,506 - Filed: 2020-04-06 - Published: 2021-01-07 - Granted: 2024-02-20 - Earliest claimed: 2019-07-01 - Assignees: Velodyne Lidar USA, Inc. - Applicants: Velodyne Lidar USA, Inc. - Inventors: Matthew Rekow; Stephen Nestinger; Aaron Chen - Web page: https://patentgrep.com/patent/US11906670B2 ## CPC - G01S 7/4876: {by removing unwanted signals (G01S7/495 takes precedence)} - G01S 17/10: using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) - G01S 17/87: Combinations of systems using electromagnetic waves other than radio waves - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract Methods, apparatus, and systems related to light detection and ranging (LIDAR) are described. In one example aspect, a LIDAR apparatus includes a light emitter configured to generate, according to a first electrical pulse signal, a pulse light signal. The first electrical pulse signal comprises a first set of non-uniformly spaced pulses. The apparatus includes a receiver configured to convert returned light signals from the object into electrical signals and a filtering subsystem in communication with the receiver, configured to receive the electrical signals from the receiver and remove a point from a set of points representing at least a partial surface of the object as noise by determining whether there is a coherence between the point and corresponding neighboring points of the point along at least a first direction and a second direction of the set of points. ## Claims ### Claim 1 A light detection and ranging apparatus, comprising: a light emitter configured to generate, according to a first electrical pulse signal, a first light signal comprising one or more pulses; a receiver configured to receive a return light signal, wherein a controller in communication with the receiver is configured to generate one more points in a point cloud based on the return light signal, wherein the point cloud includes a set of points representing a partial surface of an object and a subsystem, configured to identify as noise a target point from the set of points representing the partial surface of the object by determining whether there is a coherence between the target point and a first neighboring point of the target point along a first direction and a coherence between the target point and a second neighboring point of the target point along a second direction, wherein the first neighboring point and the second neighboring point are from the set of points representing the partial surface of the object in the point cloud. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein a dithering technique randomizes one or more firing times of the respective one or more pulses of the first light signal. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the dithering technique is combined with a pulse signature of the first light signal to reduce a likelihood of signal interference. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the controller is further configured to facilitate the generation of the first light signal by the light emitter. ### Claim 5 (depends on 4) The apparatus of claim 4, wherein the controller has one or more processors and memory. ### Claim 6 (depends on 1) The apparatus of claim 1, further comprising a network adapter configured to facilitate communication over a network. ### Claim 7 (depends on 6) The apparatus of claim 6, wherein the network adapter is further configured to communicate with at least one remote device to process and store data remotely. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the subsystem is further configured to estimate a confidence of validity of a determination that the target point is noise. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein the subsystem is further configured to remove the target point identified as noise from the set of points. ### Claim 10 (depends on 1) The apparatus of claim 1, wherein the first electrical pulse signal has a first set of non-uniformly spaced pulses. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein the one or more pulses of the first light signal have a pulse signature including the first set of non-uniformly spaced pulses. ### Claim 12 A method for light detection and ranging, comprising: emitting, by a light emitter, a first light signal according to an electrical pulse signal, the first light signal comprising one or more pulses; receiving, by a receiver, one or more return light signals reflected by an object; converting, by the receiver, the one or more return light signals into electrical signals, wherein said electrical signals are used to generate one or more points in a point cloud, wherein the point cloud includes a set of points representing a partial surface of the object; and identifying as noise a target point from the set of points representing the partial surface of the object by determining whether there is a coherence between the target point and a first neighboring point of the target point along a first direction and a coherence between the target point and a second neighboring point of the target point along a second direction, wherein the first neighboring point and the second neighboring point are from the set of points representing the partial surface of the object in the point cloud. ### Claim 13 (depends on 12) The method of claim 12, further comprising performing a dithering technique to randomize one or more firing times of the respective one or more pulses of the first light signal. ### Claim 14 (depends on 13) The method of claim 13, further comprising combining the dithering technique with a pulse signature of the first light signal to reduce a likelihood of signal interference with other light signals. ### Claim 15 (depends on 12) The method of claim 12, further comprising facilitating, by a network adapter, communication over a network. ### Claim 16 (depends on 15) The method of claim 15, further comprising communicating, by the network adapter, with at least one remote device to process and store data remotely. ### Claim 17 (depends on 12) The method of claim 12, further comprising estimating a confidence of validity of a determination that the target point is noise. ### Claim 18 (depends on 12) The method of claim 12, further comprising removing the target point from the set of points. ### Claim 19 (depends on 12) The method of claim 12, wherein the electrical pulse signal has a first set of non-uniformly spaced pulses. ### Claim 20 (depends on 19) The method of claim 19, wherein the one or more pulses of the first light signal have a pulse signature including the first set of non-uniformly spaced pulses. ### Claim 21 A non-transitory computer readable medium having processor code stored thereon including program code for performing operations comprising: emitting, by a light emitter, a first light signal according to an electrical pulse signal, the first light signal comprising one or more pulses; receiving, by a receiver, one or more return light signals reflected by an object; converting, by the receiver, the one or more return light signals into electrical signals, wherein said electrical signals are used to generate one or more points in a point cloud, wherein the point cloud includes a set of points representing a partial surface of the object; and identifying as noise a target point from the set of points representing the partial surface of the object by determining whether there is a coherence between the target point and a first neighboring point of the target point along a first direction and a coherence between the target point and a second neighboring point of the target point along a second direction, wherein the first neighboring point and the second neighboring point are from the set of points included in the point cloud. ### Claim 22 (depends on 21) The non-transitory computer readable medium of claim 21, wherein the operations further comprise performing a dithering technique to randomize one or more firing times of the respective one or more pulses of the first light signal. ### Claim 23 (depends on 22) The non-transitory computer readable medium of claim 22, wherein the operations further comprise combining the dithering technique is with a pulse signature of the first light signal to reduce a likelihood of signal interference with other light signals. ### Claim 24 (depends on 21) The non-transitory computer readable medium of claim 21, wherein the operations further comprise estimating a confidence of validity of a determination that the target point is noise. ### Claim 25 (depends on 21) The non-transitory computer readable medium of claim 21, wherein the operations further comprise removing the target point from the set of points. ### Claim 26 (depends on 21) The non-transitory computer readable medium of claim 21, wherein the electrical pulse signal has a first set of non-uniformly spaced pulses. ### Claim 27 (depends on 26) The non-transitory computer readable medium of claim 26, wherein the one or more pulses of the first light signal have a pulse signature including the first set of non-uniformly spaced pulses. ### Claim 28 (depends on 26) The non-transitory computer readable medium of claim 26, wherein two adjacent pulses of the first set of non-uniformly spaced pulses are separated by a randomized distance in time domain.