# US 10,768,194 B2 · System and method for speed estimation, detection and ranging using visible light in vehicles > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,768,194 B2 - Document ID: US10768194B2 - Status: Granted - Kind: B2 - Application number: 16/057,239 - Filed: 2018-08-07 - Published: 2019-02-07 - Granted: 2020-09-08 - Earliest claimed: 2017-08-07 - Assignees: The Board of Regents for Oklahoma State University; Ozyegin University - Applicants: The Board of Regents for Oklahoma State University; Özye{hacek over (g)}in University - Inventors: Hisham Fadlallah M. Abuella; Sabit Ekin; Murat Uysal - Web page: https://patentgrep.com/patent/US10768194B2 ## CPC - G01P 3/36: Devices characterised by the use of optical means, e.g. using infrared, visible, or ultraviolet light (G01P3/68 takes precedence; gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams G01C19/64) - G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G}) ## Abstract There is provided herein a visible light-based speed estimation method ViLDAR. By using the received light intensity of a vehicle's LED headlight, the vehicle speed can be accurately estimated for a wide range of incidence angle. Linear LS method is used in one embodiment of a speed estimation algorithm. The impact of system parameters on speed estimation error and the performance of algorithm for different speed and estimation duration are provided. Some embodiments operate best at a certain distances where the received light intensity (power) reading can provide estimation results with high accuracy, which distances are termed a reliable region of operation. In addition to speed estimation, potential applications of ViLDAR idea are ranging detection and collision avoidance for autonomous vehicles. ## Claims ### Claim 1 An apparatus for determining the speed of a vehicle, comprising, (a) a photodetector, said photodetector at least for emitting a signal representative of a light power received thereby; (b) a CPU in electronic communication with said photodetector, said CPU at least for reading a signal from said photodetector; (c) a display device in electronic communication with said CPU; (d) computer memory in communication with said CPU, said computer memory containing a plurality of commands for executing at least the following steps (1) determining values for K, γ, and d, where, K is a constant value that represents a minimum path loss at a reference distance, γ is a constant that represents a light power's rate of change as a function of distance, and, d is a constant that represents a distance between the vehicle's line of motion and a position of the photodetector; (2) reading said photodetector, thereby acquiring a Pr(t) value, where Pr(t) is a power level received from the vehicle at a time t; (3) performing step (2) a plurality of times, thereby acquiring a plurality of different Pr(t) values at a plurality of different time values; (4) using at least said determined values for K, γ, and d, and said plurality of Pr(t) values to obtain an estimate of said speed of said vehicle by solving the equation: ( P r ⁡ ( t ) K ) - 2 ⁢ ⁢ d 2 = Vt + R o , for V and R0, where V is an estimate of said speed of said vehicle, and, R0 is an initial range between the vehicle and said photodetector; and (5) displaying said speed estimate to a user using said display device. ### Claim 2 (depends on 1) The apparatus according to claim 1, wherein said display device is selected from the group consisting of an LED display device, an LCD display device, and an OLED display device. ### Claim 3 (depends on 1) The apparatus according to claim 1, wherein said reference distance is 1 meter. ### Claim 4 (depends on 1) The apparatus according to claim 1, wherein K is less than 1.0. ### Claim 5 (depends on 1) The apparatus according to claim 1, wherein 1<γ<5. ### Claim 6 A method for determining the speed of a vehicle, wherein is provided a photodetector, comprising the steps of: (a) determining values for K, γ, and d, where, K is a constant value that represents a minimum path loss at a reference distance, γ is a constant that represents a light power's rate of change as a function of distance, and, d is a constant that represents a distance between the vehicle's line of motion and a position of the photodetector; (b) reading said photodetector, thereby acquiring a Pr(t) value, where Pr(t) is a power level received from the vehicle at a time t; (c) performing step (b) a plurality of times, thereby acquiring a plurality of different Pr(t) values at a plurality of different time values; (d) using at least said determined values for K, γ, and d, and said plurality of Pr(t) values to obtain an estimate of said speed of said vehicle by solving the equation: ( P r ⁡ ( t ) K ) - 2 ⁢ ⁢ d 2 = Vt + R o , for V and R0, where V is an estimate of said speed of said vehicle, and, R0 is an initial range between the vehicle and said photodetector; and (e) displaying said speed estimate to a user using a display device in electronic communication with said photodetector. ### Claim 7 (depends on 6) The method according to claim 6, wherein said display device is selected from the group consisting of an LED display device, an LCD display device, and an OLED display device. ### Claim 8 (depends on 6) The method according to claim 6, wherein step (d) comprises the step of: (d1) using at least said accessed values for K, γ, and d, and said plurality of Pr(t) values, to obtain an linearized estimate of said speed of said vehicle. ### Claim 9 (depends on 6) The method according to claim 6, wherein said reference distance is 1 meter. ### Claim 10 (depends on 6) The method according to claim 6, wherein K is less than 1.0. ### Claim 11 (depends on 6) The method according to claim 6, wherein 1<γ<5. ### Claim 12 An apparatus for determining the speed of a vehicle, comprising, (a) a photodetector, said photodetector at least for emitting a signal representative of a light power received thereby; (b) a CPU in electronic communication with said photodetector, said CPU at least for reading a signal from said photodetector; (c) a display device in electronic communication with said CPU; (d) computer memory in communication with said CPU, said computer memory containing a plurality of commands for executing at least the following steps (1) determining values for K, γ, and d, where, K is a constant value that represents a minimum path loss at a reference distance, γ is a constant that represents a light power's rate of change as a function of distance, and, d is a constant that represents a distance between the vehicle's line of motion and a position of the photodetector; (2) reading said photodetector, thereby acquiring a Pr(t) value, where Pr(t) is a power level received from the vehicle at a time t; (3) performing step (2) a plurality of times, thereby acquiring a plurality of different Pr(t) values at a plurality of different time values; (4) using at least said determined values for K, γ, and d, and said plurality of Pr(t) values to obtain an estimate of said speed of said vehicle by solving the equation: ( P r ⁡ ( t ) K ) - 2 ⁢ d 2 = Vt + R o , for V and R0, where V is an estimate of said speed of said vehicle, and, R0 is an initial range between the vehicle and said photodetector; (5) displaying said speed estimate to a user using said display device. ### Claim 13 (depends on 12) The apparatus according to claim 12, wherein said reference distance is 1 meter. ### Claim 14 (depends on 12) The apparatus according to claim 12, wherein K is less than 1.0. ### Claim 15 (depends on 12) The apparatus according to claim 12, wherein 1 <γ<5.