# US 11,112,490 B2 ยท Apparatus for joint calibration of radar and camera systems for autonomous vehicle applications > Agents: this data is available as JSON from the patentgrep API and MCP server โ€” see https://patentgrep.com/llms.txt - Number: US 11,112,490 B2 - Document ID: US11112490B2 - Status: Granted - Kind: B2 - Application number: 16/383,829 - Filed: 2019-04-15 - Published: 2020-10-15 - Granted: 2021-09-07 - Earliest claimed: 2019-04-15 - Assignees: Argo AI, LLC - Applicants: Argo AI, LLC - Inventors: Duc Vu; Dikpal Reddy; Cole Hartman - Web page: https://patentgrep.com/patent/US11112490B2 ## CPC - G01S 7/40: Means for monitoring or calibrating - B60R 11/04: Mounting of cameras operative during drive; Arrangement of controls thereof relative to the vehicle - G01S 7/4026: {Antenna boresight} - G01S 13/865: {Combination of radar systems with lidar systems} - G01S 13/867: {Combination of radar systems with cameras} - G01S 13/931: of land vehicles - G01S 17/931: of land vehicles - G05D 1/0248: {in combination with a laser (lasers per se H01S)} - G05D 1/0257: {using a radar (radar systems designed for anti-collision purposes between land vehicles or between land vehicle and fixed obstacles G01S13/931)} - H01Q 1/3233: {particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems} - H01Q 5/22: RF wavebands combined with non-RF wavebands, e.g. infrared or optical - H01Q 15/18: comprising plurality of mutually inclined plane surfaces, e.g. corner reflector {(H01Q15/16 takes precedence)} - G01S 7/4086: {in a calibrating environment, e.g. anechoic chamber} - 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 - B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract An apparatus and method for joint calibration of vision and radar sensors for an autonomous device is disclosed. The apparatus may include a spherical portion and a cutout portion. The cutout portion may be formed within the spherical portion and have three equal surfaces. Additionally, the apparatus may include a trihedral reflector positioned within the cutout portion. ## Claims ### Claim 1 A joint sensor calibration target comprising: a spherical portion; a cutout portion, wherein the cutout portion is formed within the spherical portion and comprises three equal surfaces; and a trihedral reflector positioned within the cutout portion. ### Claim 2 (depends on 1) The joint sensor calibration target of claim 1, wherein the spherical portion comprises one or more non-metallic materials. ### Claim 3 (depends on 2) The joint sensor calibration target of claim 2, wherein the material is one or more of polystyrene, polypropylene, polyvinyl chloride (PVC), polyamide, polycarbonate (PC), polycarbonate and polybutylene terephthalate blend (PC-PBT), acrylonitrile butadiene styrene (ABS), and acrylonitrile styrene acrylate (ASA). ### Claim 4 (depends on 1) The joint sensor calibration target of claim 1, wherein the spherical portion is visually opaque. ### Claim 5 (depends on 1) The joint sensor calibration target of claim 1, wherein the trihedral reflector comprises a metallic material. ### Claim 6 (depends on 5) The joint sensor calibration target of claim 5, wherein the trihedral reflector comprises a preformed metallic insert having three surfaces of equal size and shape. ### Claim 7 (depends on 5) The joint sensor calibration target of claim 5, wherein the trihedral reflector comprises a metallic coating applied to the three surfaces of the cutout portion. ### Claim 8 (depends on 1) The joint sensor calibration target of claim 1, wherein a volume of the cutout portion is โ…› of a volume of spherical portion. ### Claim 9 (depends on 1) The joint sensor calibration target of claim 1, wherein a length of each opposite and adjacent side of each triangular surface of the trihedral reflector is equal to the radius of the spherical portion. ### Claim 10 (depends on 1) The joint sensor calibration target of claim 1, further comprising a base portion coupled to the spherical portion. ### Claim 11 (depends on 10) The joint sensor calibration target of claim 10, wherein the base portion comprises one or more of a polystyrene, polypropylene, polyvinyl chloride (PVC), polyamide, polycarbonate (PC), polycarbonate and polybutylene terephthalate blend (PC-PBT), acrylonitrile butadiene styrene (ABS), or acrylonitrile styrene acrylate (ASA) material. ### Claim 12 A system for joint calibration of vision and radar sensors comprising: an autonomous device having at least one camera sensor and at least one radar sensor; and a calibration target configured to aid calibration of the at least one camera sensor and the at least one radar sensor simultaneously, wherein the calibration target comprises: a spherical portion; a cutout portion, wherein the cutout portion is formed within the spherical portion and comprises three surfaces; and a trihedral reflector positioned within the cutout portion. ### Claim 13 (depends on 12) The system of claim 12, wherein the autonomous device comprises an autonomous vehicle. ### Claim 14 (depends on 12) The system of claim 12, wherein the spherical portion of the calibration target is formed of one or more of a polystyrene, polypropylene, polyvinyl chloride (PVC), polyamide, polycarbonate (PC), polycarbonate and polybutylene terephthalate blend (PC-PBT), acrylonitrile butadiene styrene (ABS), or acrylonitrile styrene acrylate (ASA) material. ### Claim 15 (depends on 12) The system of claim 12, wherein the trihedral reflector of the calibration target comprises a metallic material. ### Claim 16 (depends on 15) The system of claim 15, wherein the trihedral reflector of the calibration target comprises a preformed metallic insert having three surfaces of equal size and shape. ### Claim 17 (depends on 15) The system of claim 15, wherein the trihedral reflector of the calibration target comprises a metallic coating applied to the three surfaces of the cutout portion. ### Claim 18 A method of forming a calibration target for the joint calibration of vision and radar sensors for an autonomous device, the method comprising: forming a spherical portion; forming a cutout portion within the spherical portion, wherein the cutout portion is formed so as to comprise three surfaces of equal size and shape; and providing a metallic trihedral reflector positioned within the cutout portion. ### Claim 19 (depends on 18) The method of claim 18, wherein forming the spherical portion comprises forming the spherical portion from one or more of a polystyrene, polypropylene, polyvinyl chloride (PVC), polyamide, polycarbonate (PC), polycarbonate and polybutylene terephthalate blend (PC-PBT), acrylonitrile butadiene styrene (ABS), or acrylonitrile styrene acrylate (ASA) material. ### Claim 20 (depends on 18) The method of claim 18, wherein forming the cutout portion comprises removing a portion of the spherical portion equal to โ…› of the volume of spherical portion. ### Claim 21 (depends on 1) The joint sensor calibration target of claim 1, wherein the spherical portion is configured to have a fixed diameter. ### Claim 22 (depends on 18) The method of claim 18, wherein the spherical portion is configured to have a fixed diameter.