ToF Sensor Glare Detection Using Spaced Laser Emitters
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Solution Overview
Problem
Time-of-flight sensors are unreliable in environments with high reflectivity and struggle to accurately interpret multiple objects at different distances, leading to unreliable data and decreased efficiency in obstacle detection for safe travel.
Innovation Solution
The use of multiple emitters spaced differently from a sensor to emit laser pulses, allowing for comparison of distance data to determine if it is affected by glare from retroreflectors, with a confidence value adjustment or data discard based on the difference, improving the accuracy of distance measurements and object characterization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single emitter is used in a time-of-flight sensor, then the device complexity is reduced, but the measurement precision deteriorates in environments with high reflectivity due to glare from retroreflectors
Solution Approach 1:
The patent divides the single emitter function into multiple emitters (first emitter and second emitter) positioned at different locations. Each emitter independently measures distance to the same target, allowing comparison of results to detect and eliminate glare-induced errors from retroreflectors, thereby improving measurement precision without excessive complexity increase
Solution Approach 2:
The patent introduces an intermediary comparison mechanism that analyzes the difference between distance measurements from multiple emitters. This intermediary process identifies when glare is present (when measurements differ significantly) and adjusts or discards affected data, serving as a mediator between the raw sensor data and the final accurate distance measurement
2Measurement precision
If multiple emitters are used to detect and correct glare, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The system uses multiple emitters positioned at different locations relative to the sensor, creating segmented measurement paths. This segmentation allows the system to capture different perspectives of the same target, enabling glare detection through comparison while keeping each individual emitter relatively simple
Solution Approach 2:
The patent changes the spatial parameter (position) of the emitters rather than complicating the emitter design itself. By positioning emitters at different locations, the system achieves glare detection capability through geometric diversity, improving precision without increasing the complexity of individual emitter components
3Loss of time
If traditional single-emitter ToF sensors are used, then the processing time is reduced, but the reliability of sensor data deteriorates in environments with multiple objects at different distances
Solution Approach 1:
The patent performs preliminary comparison of distance measurements from multiple emitters to identify potential glare issues before final data processing. By detecting inconsistencies early in the measurement process, the system can flag or discard affected data points, improving reliability without requiring extensive post-processing time
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
This approach enhances the reliability and accuracy of sensor data, enabling safer navigation by reducing the impact of glare and improving object detection and characterization, particularly in environments with high reflectivity and multiple objects at varying distances.
Implementation Method 1
time-of-flight (ToF) sensors
Implementation Method 2
emit laser pulses
Implementation Method 3
glare associated with a retroreflector
Implementation Method 4
high reflectivity
Data Source
AI summary
Techniques for determining a distance to an object in an environment based on sensor data are discussed herein. The sensor data can be captured by a sensor, and the sensor data can be based on laser pulses emitted from emitters being differently spaced apart from the sensor. The sensor data can be utilized to determine distance data associated with an object. A difference between the distance data can be used to determine whether the distance data is associated with a retroreflector. If the difference in distance data is above a threshold, a confidence level of sensor data can be adjusted or the sensor data can be discarded or omitted from subsequent processing.