LiDAR Road Sign Recognition with Non-Visible Data Encoding
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Solution Overview
Problem
Existing LIDAR and SWIR systems in autonomous vehicles struggle to accurately detect and decode embedded information on road signs and objects using non-visible light spectra without cluttering the driver's visible view.
Innovation Solution
Implementing chemical coatings and wavelength selective retroreflectors on road signs and objects to encode digital data in infrared wavelengths, allowing LIDAR and SWIR sensors to capture and decode this information, while maintaining the visible appearance of the signs and objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LIDAR and SWIR systems use non-visible light spectra to detect embedded information on road signs, then detection accuracy of embedded data is improved, but the driver's visible view may be cluttered or compromised
Solution Approach 1:
The system segments the electromagnetic spectrum into visible and non-visible portions, using non-visible wavelengths (infrared, ultraviolet) for embedded information encoding while keeping the visible spectrum clear for driver observation. This allows simultaneous operation of embedded data detection and normal visual driving without interference.
Solution Approach 2:
Different regions of the road sign are treated differently: the visible portion maintains standard visual characteristics for driver viewing, while specific localized regions contain embedded information encoded in non-visible light spectra. This allows the sign to serve dual functions without compromising either purpose.
2Loss of information
If chemical coatings and wavelength selective retroreflectors are applied to road signs to encode digital data, then information capacity of road signs is improved, but manufacturing complexity increases
Solution Approach 1:
The road signs use composite structures combining chemical coatings with wavelength-selective retroreflector materials. These composite materials encode digital information through their optical properties at different wavelengths, enabling high information capacity while maintaining a relatively streamlined manufacturing process through material integration.
Solution Approach 2:
The system encodes information by changing optical parameters (reflectivity, absorption) of the sign materials at specific wavelengths. By varying these physical parameters through chemical treatments and material selection, digital data is embedded without requiring complex mechanical or structural modifications to the sign.
3Measurement precision
If LIDAR emits pulses at multiple designated wavelengths to capture reflected light, then accuracy of point cloud generation is improved, but energy consumption increases
Solution Approach 1:
The LIDAR system emits light pulses periodically at multiple designated wavelengths in sequence rather than continuously at all wavelengths simultaneously. This periodic multi-wavelength approach maintains accurate point cloud generation by capturing reflected light at different spectral bands while reducing overall energy consumption through time-multiplexed operation.
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
Enables accurate detection and decoding of embedded data from road signs and objects, enhancing vehicle systems with additional information beyond the visible content, improving safety and functionality without distracting the driver.
Implementation Method 1
receiving a set of reflected pulses of light with a receiver on the distance sensor that correspond to the pulses of light reflected off a surface of an object
Implementation Method 2
the pattern is generated by at least one of a chemical treatment or a retroreflector on the surface of the object
Data Source
AI summary
A method of operating a distance sensor includes emitting pulses of light from an emitter on the distance sensor at one or more designated wavelengths in a non-visible spectrum and receiving a set of reflected pulses of light with a receiver on the distance sensor that correspond to the pulses of light reflected off a surface of an object within a line-of-sight of the receiver. A point cloud is generated of an area including the surface of the object based on the set of reflected pulses of light. A pattern is identified on a surface of the object based on at least one of an area of increased or decreased reflectivity for the one or more designated wavelengths in the non-visible spectrum identified in the point cloud. Embedded data is decoded from the pattern on the surface of the object.