# US 2023/0058081 A1 · System and methods for depth generation using structured light patterns > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0058081 A1 - Document ID: US20230058081A1 - Status: Published application - Kind: A1 - Application number: 17/719,008 - Filed: 2022-04-12 - Published: 2023-02-23 - Earliest claimed: 2021-08-17 - Assignees: Texas Instruments Incorporated - Applicants: Texas Instruments Incorporated - Inventors: Shashank Dabral; Jaime De La Cruz; Jeffrey Kempf - Web page: https://patentgrep.com/patent/US20230058081A1 ## CPC - G01S 17/89: for mapping or imaging - G01S 17/931: of land vehicles - G01B 11/026: {by measuring distance between sensor and object (G01B11/0608 takes precedence)} - G01B 11/25: by projecting a pattern, e.g. {one or more lines,} moiré fringes on the object (G01B11/255 takes precedence {; image analysis for depth or shape recovery G06T7/50}) - G01B 11/2504: {Calibration devices} - G01B 11/254: {Projection of a pattern, viewing through a pattern, e.g. moiré} - G01S 17/894: Three-dimensional [3D] imaging with simultaneous measurement of time-of-flight at a two-dimensional [2D] array of receiver pixels, e.g. time-of-flight cameras or flash lidar - G06T 7/521: from laser ranging, e.g. using interferometry; from the projection of structured light - G06T 7/55: from multiple images - G06T 2207/10028: Range image; Depth image; 3D point clouds - 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 - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract An example apparatus includes: a controller configured to: generate a symbol pattern as a result of placing symbols based on epipolar lines; instruct an SLM to project the symbol pattern; obtain an image of a reflection of the symbol pattern; determine a first location of a symbol in the image; determine a second location of the symbol in the image; and determine a depth of the symbol as based on the first location, the second location, and an essential matrix. ## Claims ### Claim 1 A controller configured to: generate a symbol pattern as a result of placing symbols based on epipolar lines; instruct an SLM to project the symbol pattern; obtain an image of a reflection of the symbol pattern; determine a first location of a symbol in the image; determine a second location of the symbol in the image; and determine a depth of the symbol as based on the first location, the second location, and an essential matrix. ### Claim 2 (depends on 1) The controller of claim 1, further configured to determine the essential matrix based on a difference in rotation and translation between a camera and the SLM, the camera used to obtain the image of the reflection of the symbol pattern. ### Claim 3 (depends on 1) The controller of claim 1, further configured to determine the epipolar lines, used to generate the symbol pattern, as a result of determining possible values of the second location based on the essential matrix and the first location. ### Claim 4 (depends on 1) The controller of claim 1, further configured to generate the symbol pattern using a plurality of sequences of symbols that share an epipolar line, the sequences of symbols including a plurality of symbols that differentiate a first occurrence of the symbol on the epipolar line from a second occurrence of the symbol on the epipolar line. ### Claim 5 (depends on 1) The controller of claim 1, further configured to search along an epipolar line, used to generate the symbol pattern, corresponding to the symbol for a sequence of symbols to differentiate a first occurrence of the symbol from a second occurrence of the symbol. ### Claim 6 (depends on 1) The controller of claim 1, further configured to determine the depth of the symbol as a result of solving for a depth coordinate in an equation wherein a dot product of a transpose of the first location, the essential matrix, and the second location is equal to zero. ### Claim 7 A system comprising: a spatial light modulator (SLM) configured to project a symbol pattern; a camera configured to obtain an image of a reflection of the symbol pattern; a controller coupled to the SLM and the camera, the controller configured to: determine a first location of a symbol in the image; determine a second location of the symbol in the image; and determine a depth of the symbol as based on the first location, the second location, and an essential matrix. ### Claim 8 (depends on 7) The system of claim 7, the controller further configured to determine the essential matrix based on a difference in rotation and translation between the camera and the SLM. ### Claim 9 (depends on 7) The system of claim 7, the controller further configured to determine epipolar lines as a result of determining possible values of the second location based on the essential matrix and the first location. ### Claim 10 (depends on 9) The system of claim 9, the controller further configured to generate the symbol pattern as a result of placing symbols at symbol locations along the epipolar lines. ### Claim 11 (depends on 7) The system of claim 7, the controller further configured to generate the symbol pattern using a plurality of sequences of symbols that share an epipolar line, the sequences of symbols including a plurality of symbols that differentiate a first occurrence of the symbol on the epipolar line from a second occurrence of the symbol on the epipolar line. ### Claim 12 (depends on 7) The system of claim 7, the controller further configured to search along an epipolar line of the symbol for a sequence of symbols to differentiate a first occurrence of the symbol from a second occurrence of the symbol. ### Claim 13 (depends on 7) The system of claim 7, the controller further configured to determine the depth of the symbol as a result of solving for a depth coordinate in an equation wherein a dot product of a transpose of the first location, the essential matrix, and the second location is equal to zero. ### Claim 14 A vehicle comprising: a headlight comprising: a spatial light modulator (SLM) configured to project a symbol pattern; a camera configured to obtain an image of a reflection of the symbol pattern; and a controller coupled to the SLM and the camera, the controller configured to: determine a first location of a symbol in the symbol pattern; determine a second location of the symbol in the image; and determine a depth of the symbol as based on the first location, the second location, and an essential matrix. ### Claim 15 (depends on 14) The vehicle of claim 14, the controller further configured to determine the essential matrix based on a difference in rotation and translation between the camera and the SLM. ### Claim 16 (depends on 14) The vehicle of claim 14, further configured to determine epipolar lines as a result of determining possible values of the second location based on the essential matrix and the first location. ### Claim 17 (depends on 16) The vehicle of claim 16, further configured to generate the symbol pattern as a result of placing symbols at symbol locations along the epipolar lines. ### Claim 18 (depends on 14) The vehicle of claim 14, further configured to generate the symbol pattern using a plurality of sequences of symbols that share an epipolar line, the sequences of symbols including a plurality of symbols that differentiate a first occurrence of the symbol on the epipolar line from a second occurrence of the symbol on the epipolar line. ### Claim 19 (depends on 14) The vehicle of claim 14, further configured to search along an epipolar line of the symbol for a sequence of symbols to differentiate a first occurrence of the symbol from a second occurrence of the symbol. ### Claim 20 (depends on 14) The vehicle of claim 14, further configured to determine the depth of the symbol as a result of solving for a depth coordinate in an equation wherein a dot product of a transpose of the first location, the essential matrix, and the second location is equal to zero.