# US 12,112,492 B2 · Three-dimensional sensing device and specular reflection object detection method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,112,492 B2 - Document ID: US12112492B2 - Status: Granted - Kind: B2 - Application number: 17/691,133 - Filed: 2022-03-10 - Published: 2023-09-14 - Granted: 2024-10-08 - Earliest claimed: 2022-03-10 - Assignees: Himax Technologies Limited - Applicants: Himax Technologies Limited - Inventors: Wu-Feng Chen; Pen-Hsin Chen; Cheng-Che Tsai; Hsueh-Tsung Lu - Web page: https://patentgrep.com/patent/US12112492B2 ## CPC - G06T 7/44: using image operators, e.g. filters, edge density metrics or local histograms - G06T 7/521: from laser ranging, e.g. using interferometry; from the projection of structured light - G06T 7/514: from specularities - G06T 7/586: from multiple light sources, e.g. photometric stereo - G06T 2207/10052: Images from lightfield camera - G06T 2207/10152: Varying illumination - G06T 2207/20021: Dividing image into blocks, subimages or windows - G06T 2207/20221: Image fusion; Image merging - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract A three-dimensional (3D) sensing device is configured to sense an object. The 3D sensing device includes a flood light source, a structured light source, an image sensor, and a controller. The controller is configured to perform: commanding the flood light source and the structured light source to emit a flood light and a structured light in sequence; commanding the image sensor to sense a first reflective light and a second reflective light in sequence, so as to obtain a first image frame and a second image frame; combining the first image frame and the second image frame into a determination frame; and determining that the object is a specular reflection object in response to determining that the determination frame has at least two spots having gray levels satisfying a predetermined condition. A specular reflection object detection method is also provided. ## Claims ### Claim 1 A three-dimensional (3D) sensing device configured to sense an object, the 3D sensing device comprising: a flood light source configured to emit a flood light to the object, wherein the object reflects the flood light into a first reflective light; a structured light source configured to emit a structured light to the object, wherein the object reflects the structured light into a second reflective light; an image sensor configured to sense the first reflective light and the second reflective light; and a controller electrically connected to the flood light source, the structured light, and the image sensor, and configured to perform: commanding the flood light source and the structured light source to emit the flood light and the structured light in sequence; commanding the image sensor to sense the first reflective light and the second reflective light in sequence, so as to obtain a first image frame corresponding to the first reflective light and a second image frame corresponding to the second reflective light; combining the first image frame and the second image frame into a determination frame; and determining that the object is a specular reflection object in response to determining that the determination frame has at least two spots having gray levels satisfying a predetermined condition. ### Claim 2 (depends on 1) The 3D sensing device according to claim 1, wherein combing the first image frame and the second image frame into the determination frame comprises: calculating difference values between gray levels of pixels of the first image frame and gray levels of corresponding pixels of the second image frame; and calculating absolute values of the difference values to respectively form gray levels of pixels of the determination frame. ### Claim 3 (depends on 1) The 3D sensing device according to claim 1, wherein the predetermined condition is that a gray level is greater than a first threshold value. ### Claim 4 (depends on 3) The 3D sensing device according to claim 3, wherein determining that the determination frame has at least two spots having gray levels satisfying the predetermined condition comprises: dividing the determination frame into a plurality of regions; finding regions having an average of gray levels less than a second threshold value; and determining that the determination frame has at least two spots having gray levels satisfying the predetermined condition in response to determining the number of spots having gray levels greater than the first threshold value is greater than or equal to a third threshold value. ### Claim 5 (depends on 4) The 3D sensing device according to claim 4, wherein the third threshold value is 2. ### Claim 6 (depends on 4) The 3D sensing device according to claim 4, wherein the regions are arranged in a rectangular array. ### Claim 7 (depends on 1) The 3D sensing device according to claim 1, wherein the at least two spots are contributed by the specular reflection object specularly reflecting the flood light and the structured light. ### Claim 8 (depends on 7) The 3D sensing device according to claim 7, wherein the specular reflection object comprises a transparent object. ### Claim 9 (depends on 8) The 3D sensing device according to claim 8, wherein a material of the transparent object comprises glass. ### Claim 10 A specular reflection object detection method comprising: commanding a flood light source to emit a flood light and a structured light source to emit a structured light in sequence; commanding an image sensor to sense a first reflective light formed by an object reflecting the flood light and a second reflective light formed by the object reflecting the structured light in sequence in sequence, so as to obtain a first image frame corresponding to the first reflective light and a second image frame corresponding to the second reflective light; combining the first image frame and the second image frame into a determination frame; and determining that the object is a specular reflection object in response to determining that the determination frame has at least two spots having gray levels satisfying a predetermined condition. ### Claim 11 (depends on 10) The specular reflection object detection method according to claim 10, wherein combing the first image frame and the second image frame into the determination frame comprises: calculating difference values between gray levels of pixels of the first image frame and gray levels of corresponding pixels of the second image frame; and calculating absolute values of the difference values to respectively form gray levels of pixels of the determination frame. ### Claim 12 (depends on 10) The specular reflection object detection method according to claim 10, wherein the predetermined condition is that a gray level is greater than a first threshold value. ### Claim 13 (depends on 12) The specular reflection object detection method according to claim 12, wherein determining that the determination frame has at least two spots having gray levels satisfying the predetermined condition comprises: dividing the determination frame into a plurality of regions; finding regions having an average of gray levels less than a second threshold value; and determining that the determination frame has at least two spots having gray levels satisfying the predetermined condition in response to determining the number of spots having gray levels greater than the first threshold value is greater than or equal to a third threshold value. ### Claim 14 (depends on 13) The specular reflection object detection method according to claim 13, wherein the third threshold value is 2. ### Claim 15 (depends on 13) The specular reflection object detection method according to claim 13, wherein the regions are arranged in a rectangular array. ### Claim 16 (depends on 10) The specular reflection object detection method according to claim 10, wherein the at least two spots are contributed by the specular reflection object specularly reflecting the flood light and the structured light. ### Claim 17 (depends on 16) The specular reflection object detection method according to claim 16, wherein the specular reflection object comprises a transparent object. ### Claim 18 (depends on 17) The specular reflection object detection method according to claim 17, wherein a material of the transparent object comprises glass.