Pulsed-Light Ranging Device for False-Detection Suppression
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Solution Overview
Problem
Ranging devices mounted to vehicles face false detections due to pulsed interfering light from other ranging devices, which is not effectively suppressed by existing noise suppression methods.
Innovation Solution
A ranging device configuration that includes a light emitting unit, a light receiving unit, a characteristic setting unit, and a distance calculation unit, which integrates received-light information to exclude or identify distance noise from pulsed interfering light, using specified ranges and thresholds to suppress false detections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If received-light waveforms are integrated to suppress disturbance light, then measurement reliability is improved, but processing time and computational load increase
Solution Approach 1:
The patent applies preliminary action by performing binarization of received-light waveforms before integration. This pre-processing step converts the waveform data into a simplified binary format (0s and 1s) that is easier and faster to process during subsequent integration operations, thereby reducing overall processing time while maintaining measurement reliability
Solution Approach 2:
The patent changes the parameter representation of received-light waveforms from continuous amplitude values to discrete binary values through binarization. This parameter transformation enables more efficient integration processing and reduces computational complexity, addressing the time reliability trade-off
2Measurement precision
If multiple received-light waveforms are integrated to suppress noise, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the received-light waveform processing into distinct stages: binarization stage and integration stage. This segmentation allows each stage to be optimized independently, with binarization simplifying the data format and integration combining multiple waveforms. The segmented approach achieves high measurement precision through multi-waveform integration while managing device complexity through modular processing
3Quantity of substance
If binarization threshold is set low to capture all signals, then signal completeness is improved, but false detections from interfering light increase
Solution Approach 1:
The patent implements feedback mechanisms through multiple threshold levels and validation steps. After binarization with a low threshold to capture all signals, the system uses feedback from the integration process and subsequent validation stages to identify and filter out false detections from interfering light, while maintaining signal completeness through the initial low threshold setting
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
The solution effectively suppresses false detections by integrating received-light information, allowing accurate distance calculations to objects while reducing processing load and memory requirements.
Implementation Method 1
emitting light and receiving reflected light from an object
Implementation Method 2
receiving reflected light from an object
Implementation Method 3
uses an array of multiple SPADs as a photodetector
Data Source
AI summary
In a ranging device, a characteristic setting unit is configured to extract, from one or more pieces of received-light information representing changes with time in amount of received light acquired by the light receiving unit, at least one of a received-light amount range and a light reception time range of pulsed light other than emitted light from the light emitting unit, as a specified range. A received-light integration unit is configured to generate integrated received-light information by integrating the received-light information on a time axis with emission timings matched over a plurality of light receptions. A distance calculation unit is configured to exclude or identify distance noise formed of pulsed waveforms arising from pulsed light other than the emitted light, using the specified range extracted by the characteristic setting unit, and calculate a distance to the object reflecting the emitted light.