# US 12,593,976 B2 · Systems and methods for measuring visual axis of the eye > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,593,976 B2 - Document ID: US12593976B2 - Status: Granted - Kind: B2 - Application number: 18/194,532 - Filed: 2023-03-31 - Published: 2023-08-03 - Granted: 2026-04-07 - Earliest claimed: 2020-10-12 - Applicants: Xiaochun Nie - Inventors: Xiaochun Nie - Web page: https://patentgrep.com/patent/US12593976B2 ## CPC - A61B 3/113: for determining or recording eye movement - A61B 3/1005: {for measuring distances inside the eye, e.g. thickness of the cornea (A61B3/11 takes precedence)} - A61B 3/14: Arrangements specially adapted for eye photography - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract Disclosed herein are methods for determining an angular offset between a visual axis of a person's eye and an optical axis of the eye, or an angular offset between a line of sight of the eye and the optical axis of the eye. ## Claims ### Claim 1 A computer program product comprising a non-transitory computer readable medium having instructions recorded thereon, the instructions when executed by a computer implementing a method comprising: while a person's head is at a first pose and the person's eye is gazing at a point in a 3D space, obtaining a first orientation of the eye with respect to an image sensor and a first orientation of a spatial orientation sensor with respect to the 3D space; while the person's head is at a second pose and the person's eye is gazing at the point, obtaining a second orientation of the eye with respect to the image sensor and a second orientation of the spatial orientation sensor with respect to the 3D space; wherein the first pose and the second pose are different; determining an angular offset between a visual axis of the eye and an optical axis of the eye, or an angular offset between a line of sight of the eye and the optical axis of the eye, based on: the first orientation of the eye, the first orientation of the spatial orientation sensor, the second orientation of the eye, the second orientation of the spatial orientation sensor, and an orientation of the image sensor relative to the spatial orientation sensor or an orientation of the spatial orientation sensor relative to the image sensor; wherein the image sensor and the spatial orientation sensor do not move relative to each other. ### Claim 2 (depends on 1) The computer program product of claim 1, wherein the image sensor is configured to image the eye. ### Claim 3 (depends on 1) The computer program product of claim 1, further comprising capturing a first image of the eye while the head is at the first pose and the eye is gazing at the point in the 3D space, wherein obtaining the first orientation of the eye with respect to the image sensor is based on the first image. ### Claim 4 (depends on 1) The computer program product of claim 1, wherein the image sensor does not move relative to the head. ### Claim 5 (depends on 1) The computer program product of claim 1, wherein determining the angular offset between the visual axis of the eye and the optical axis of the eye or the angular offset between the line of sight of the eye and the optical axis of the eye is further based on a difference of positions of the eye relative to the image sensor while the person's head is at the first pose and at the second pose. ### Claim 6 (depends on 1) The computer program product of claim 1, wherein determining the angular offset between the visual axis of the eye and the optical axis of the eye or the angular offset between the line of sight of the eye and the optical axis of the eye is further based on positions of the eye relative to the 3D space while the person's head is at the first pose and at the second pose. ### Claim 7 (depends on 1) The computer program product of claim 1, wherein determining the angular offset between the visual axis of the eye and the optical axis of the eye or the angular offset between the line of sight of the eye and the optical axis of the eye is further based on positions of the image sensor relative to the 3D space while the person's head is at the first pose and at the second pose. ### Claim 8 A computer program product comprising a non-transitory computer readable medium having instructions recorded thereon, the instructions when executed by a computer implementing the method a method comprising: while a person's head is at a first pose and the person's eye is gazing at a point in a 3D space, obtaining a first orientation of the eye with respect to an image sensor; while the person's head is at a second pose and the person's eye is gazing at the point, obtaining a second orientation of the eye with respect to the image sensor; wherein the first pose and the second pose are different; determining an angular offset between a visual axis of the eye and an optical axis of the eye, or an angular offset between a line of sight of the eye and the optical axis of the eye, based on the first orientation of the eye and the second orientation of the eye; wherein the image sensor does not move relative to the 3D space. ### Claim 9 (depends on 8) The computer program product of claim 8, wherein the image sensor is configured to image the eye. ### Claim 10 (depends on 8) The computer program product of claim 8, further comprising capturing a first image of the eye while the head is at the first pose and the eye is gazing at the point in the 3D space, wherein obtaining the first orientation of the eye with respect to the image sensor is based on the first image. ### Claim 11 (depends on 8) The computer program product of claim 8, wherein determining the angular offset between the visual axis of the eye and the optical axis of the eye or the angular offset between the line of sight of the eye and the optical axis of the eye is further based on a difference of positions of the eye relative to the image sensor while the person's head is at the first pose and at the second pose. ### Claim 12 (depends on 8) The computer program product of claim 8, wherein determining the angular offset between the visual axis of the eye and the optical axis of the eye or the angular offset between the line of sight of the eye and the optical axis of the eye is further based on positions of the eye relative to the 3D space while the person's head is at the first pose and at the second pose. ### Claim 13 (depends on 8) The computer program product of claim 8, wherein determining the angular offset between the visual axis of the eye and the optical axis of the eye or the angular offset between the line of sight of the eye and the optical axis of the eye is further based on positions of the image sensor relative to the 3D space while the person's head is at the first pose and at the second pose.