# US 2025/0085402 A1 · Systems and Methods for Occlusion Detection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0085402 A1 - Document ID: US20250085402A1 - Status: Published application - Kind: A1 - Application number: 18/959,920 - Filed: 2024-11-26 - Published: 2025-03-13 - Earliest claimed: 2019-12-27 - Assignees: Waymo LLC - Applicants: Waymo LLC - Inventors: Jason Watson; Blaise Gassend - Web page: https://patentgrep.com/patent/US20250085402A1 ## CPC - G01S 7/4817: {relating to scanning} - G01S 7/497: Means for monitoring or calibrating - G01S 17/86: Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders - G01S 17/89: for mapping or imaging - G01S 17/931: of land vehicles - G06T 7/246: using feature-based methods, e.g. the tracking of corners or segments - G06V 10/141: Control of illumination - G06V 20/56: exterior to a vehicle by using sensors mounted on the vehicle - G01S 2007/4975: {of sensor obstruction by, e.g. dirt- or ice-coating, e.g. by reflection measurement on front-screen} - G01S 2007/4977: {including means to prevent or remove the obstruction} - G06T 2207/10016: Video; Image sequence - G06T 2207/10048: Infrared image - 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 - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING ## Abstract The present disclosure relates to systems and methods for occlusion detection. An example system includes a primary reflective surface and a rotatable mirror configured to rotate about a rotational axis. The rotatable mirror includes a plurality of secondary reflective surfaces. The system also includes an optical element and a camera that is configured to capture at least one image of the optical element by way of the primary reflective surface and at least one secondary reflective surface of the rotatable mirror. ## Claims ### Claim 1 A light detection and ranging (lidar) system comprising: a transmitter configured to emit light pulses into a field of view; a receiver configured to receive reflected light pulses from the field of view; an optical element in a transmit path of the transmitter and a receive path of the receiver; and a camera, wherein the camera is configured to focus on the optical element to capture at least one image of the optical element. ### Claim 2 (depends on 1) The lidar system of claim 1, further comprising: a controller having at least one processor and a memory, wherein the at least one processor executes program instructions stored in the memory so as to carry out operations, wherein the operations comprise: determining, based on the at least one image of the optical element, that at least one occlusion object is present on the optical element. ### Claim 3 (depends on 2) The lidar system of claim 2, wherein determining, based on the at least one image of the optical element, that at least one occlusion object is present on the optical element comprises: comparing the at least one image of the optical element with at least one prior image of the optical element. ### Claim 4 (depends on 2) The lidar system of claim 2, wherein the operations further comprise: determining point cloud information based on the reflected light pulses. ### Claim 5 (depends on 4) The lidar system of claim 4, wherein the operations further comprise: ignoring or adjusting a portion of the point cloud information that corresponds to a region of the field of view that could be affected by the occlusion object. ### Claim 6 (depends on 2) The lidar device of claim 2, wherein the operations further comprising: providing a notification about the occlusion object. ### Claim 7 (depends on 2) The lidar device of claim 2, wherein the operations further comprising: providing a notification about a region of the field of view that could be affected by the occlusion object. ### Claim 8 (depends on 2) The lidar system of claim 2, further comprising an illuminator, wherein the operations further comprise: causing the illuminator to emit light to illuminate the optical element while the camera captures the at least one image of the optical element. ### Claim 9 (depends on 2) The lidar system of claim 2, wherein the operations further comprise: causing the camera to capture a plurality of images of the optical element; determining an aggregate image of the optical element based on the plurality of images of the optical element; and determining, based on the aggregate image of the optical element, that at least one occlusion object is present on the optical element. ### Claim 10 (depends on 1) The lidar device of claim 1, wherein the camera is configured to focus on the optical element by way of at least one reflective surface. ### Claim 11 (depends on 10) The lidar device of claim 10, wherein the at least one reflective surface comprises a reflective surface of a rotatable mirror. ### Claim 12 (depends on 11) The lidar device of claim 11, wherein the rotatable mirror comprises a plurality of reflective surfaces. ### Claim 13 (depends on 10) The lidar device of claim 10, further comprising: an illuminator configured to emit light to illuminate the optical element by way of the at least one reflective surface. ### Claim 14 (depends on 13) The lidar device of claim 13, wherein the illuminator comprises an infrared light-emitting diode (LED). ### Claim 15 (depends on 1) The lidar device of claim 1, wherein the optical element is an optical window. ### Claim 16 (depends on 1) The lidar device of claim 1, wherein the transmitter comprises at least one light-emitter device. ### Claim 17 (depends on 1) The lidar device of claim 1, wherein the receiver comprises a plurality of photodetectors. ### Claim 18 A method comprising: emitting light pulses through an optical element into a field of view; receiving, through the optical element, reflected light pulses from the field of view; and causing a camera, which is focused on the optical element, to capture at least one image of the optical element. ### Claim 19 (depends on 18) The method of claim 18, further comprising: determining, based on the at least one image of the optical element, that at least one occlusion object is present on the optical element. ### Claim 20 (depends on 18) The method of claim 18, further comprising: causing an illuminator to emit light to illuminate the optical element while the camera captures the at least one image of the optical element.