ViLDAR Visible Light Speed Estimation for Curved Roads
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Solution Overview
Problem
Current speed detection systems, such as RADAR and LiDAR, face limitations in accuracy due to narrow beam-width requirements and line-of-sight constraints, particularly in curved road scenarios, and can be detected by drivers, whereas existing solutions fail to effectively utilize visible light for speed estimation.
Innovation Solution
The Visible Light Detection and Ranging (ViLDAR) system employs light emitting diodes (LEDs) to estimate vehicle speed using received light intensity variations, leveraging a Lambertian channel model and linear least square fitting methods, which provides better accuracy and is less susceptible to angle of incidence and noise, and operates within a wider range of incidence angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RADAR or LiDAR systems are used for speed detection, then speed estimation can be achieved, but the beam-width must be narrow which limits accuracy in curved road scenarios and requires line-of-sight
Solution Approach 1:
The patent replaces the active electromagnetic wave transmission system (RADAR/LiDAR) with a passive optical detection system that uses visible light. Instead of transmitting radio or laser waves and measuring reflections, the system detects visible light from vehicle headlights or daytime running lights, substituting mechanical/electromagnetic transmission with optical detection that naturally adapts to curved road geometries
Solution Approach 2:
The patent changes the operating wavelength from radio frequency (RADAR) or laser frequency (LiDAR) to visible light frequency. This parameter change enables the system to utilize the broader angular distribution of visible light sources in vehicles, improving adaptability to curved roads while maintaining speed estimation capability through intensity variation analysis
2Measurement precision
If RADAR systems are used for speed detection, then speed can be measured, but the system can be detected by drivers leading to illegal avoidance behaviors
Solution Approach 1:
The patent replaces the active transmission system with passive detection, substituting the mechanical principle of emitting and receiving reflected waves with the optical principle of detecting emitted visible light. This eliminates the transmission component that drivers could detect, making the speed measurement system undetectable while maintaining measurement precision through intensity variation analysis
3Measurement precision
If RADAR or LiDAR systems are used, then speed estimation is possible, but the device complexity and size are larger compared to visible light solutions
Solution Approach 1:
The patent replaces complex electromagnetic transmission and reception systems with a simpler passive optical detection system. Instead of requiring transmitters, amplifiers, and sensitive receivers for radio or laser waves, the system uses straightforward visible light detection with intensity analysis, reducing device complexity and size while maintaining speed estimation precision
Solution Approach 2:
The patent utilizes existing, inexpensive visible light sources in vehicles (headlights, daytime running lights) as the measurement target, replacing the need for expensive active transmission equipment. By leveraging these already-present light sources, the system achieves speed estimation with simpler, smaller, and more cost-effective hardware
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
ViLDAR offers improved speed estimation accuracy compared to RADAR/LiDAR systems, particularly in curved road scenarios, with reduced noise and path loss, and is undetectable by drivers, offering better battery efficiency and smaller size, while avoiding RF interference.
Implementation Method 1
a photodetector to receive the light from the vehicle
Implementation Method 2
The use of light emitting diodes (LED) in vehicles lighting systems has become increasingly common
Data Source
AI summary
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.