# US 10,769,458 B2 · Determination procedure of the luminance of traffic signs and device for its embodiment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,769,458 B2 - Document ID: US10769458B2 - Status: Granted - Kind: B2 - Application number: 15/945,199 - Filed: 2018-04-04 - Published: 2018-08-09 - Granted: 2020-09-08 - Earliest claimed: 2008-02-12 - Assignees: DBI/CIDAUT Technologies, LLC - Applicants: DBI/CIDAUT Technologies, LLC - Inventors: Francisco Javier Burgoa Roman; Jose Antonio Guiterrez Mendez; Alberto Mansilla Gallo; Diego Ortiz de Lejarazu Machin; Alberto Senen Perales Garcia - Web page: https://patentgrep.com/patent/US10769458B2 ## CPC - B60Q 1/085: {due to special conditions, e.g. adverse weather, type of road, badly illuminated road signs or potential dangers (B60Q1/10, B60Q1/12, B60Q1/1423 take precedence)} - B60Q 1/18: being additional front lights {(bracket mounted headlights B60Q1/0483)} - G01N 21/55: Specular reflectivity - G06T 5/50: using two or more images, e.g. averaging or subtraction - G06V 20/582: {of traffic signs} - H04N 13/279: the virtual viewpoint locations being selected by the viewers or determined by tracking - B60Q 2300/314: Ambient light - B60Q 2300/45: Special conditions, e.g. pedestrians, road signs or potential dangers - G01N 2021/551: {Retroreflectance} - B60Q: ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract The method of the invention comprises: obtaining a sequence of at least two images, with different levels of illumination; extracting the region containing the sign in the image; calculating the luminance values of the signs; and obtaining the difference in luminance of the sign corresponding to the two levels of illumination. The value obtained is the luminance of the sign (11) corresponding to an illumination equal to the difference between the illuminations, or additional illumination. This result is based on the additive property of luminance, according to which the luminance of a sign is the sum of the luminance produced by each source of illumination. A basic illumination device (5), an additional illumination device (7), at least one camera for taking images, and image recording, positioning and synchronism systems are required to implement the method. ## Claims ### Claim 1 A luminance detection system connectable to a vehicle and operable while the vehicle is moving along a roadway, the luminance detection system comprising: a light source configured to illuminate a road marking positioned along the roadway, the light source being separate and distinct from a pair of headlights of the vehicle; a first camera configured to obtain first image data, the first image data including the road marking, the first image data having first color characteristics; a second camera configured to obtain second image data, the second image data including the road marking also included in the first image data, the second image data having second color characteristics, wherein the first color characteristics are separate and distinct from the second color characteristics; a processor configured to: calculate a distance between the vehicle and the road marking based on the first image data and the second image data; apply one or more luminance transforms to convert one or more pixel values of the first image data and the second image data to obtain corresponding luminance levels representative of at least a portion of the road marking; after applying the one or more luminance transforms, compare the first image data, and the second image data to minimize ambient light information; and calculate a luminance value representative of a luminance of the road marking based on (i) the distance between the vehicle and the road marking (ii) the luminance levels representative of the road marking and (iii) the comparison of the first image data, after applying the luminance transform, and the second image data to minimize ambient light information. ### Claim 2 (depends on 1) The luminance detection system of claim 1, wherein at least one of the first camera and the second camera is a color camera. ### Claim 3 (depends on 1) The luminance detection system of claim 1, wherein the processor is configured to: extract pixel values representative of the road marking from the first image data and the second image data. ### Claim 4 (depends on 1) The luminance detection system of claim 1, further comprising a geo-referenced positioning device configured to generate vehicle position data representative of a position of the vehicle along the roadway, wherein the processor is configured to calculate the distance between the vehicle and the road marking based on the vehicle position data. ### Claim 5 (depends on 1) The luminance detection system of claim 1, wherein the light source is positioned at the front of the vehicle. ### Claim 6 (depends on 1) The luminance detection system of claim 1, wherein the first camera and the second camera are positioned at the front of the vehicle. ### Claim 7 (depends on 1) The luminance detection system of claim 1, further comprising: a light illumination adjustment sub-system including: a light source external to the vehicle and separate and distinct from dipped headlights of the vehicle, a sensor configured to measure an amount of light from the light source, and a controller configured to adjust the amount of light emitted by the light source as a function of the amount of light measured by the sensor.