Flash Lidar Channel Encoding to Reduce Glare False Positives
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Solution Overview
Problem
Flash lidar systems suffer from out-of-channel noise and channel mixing false positives (CMFPs) due to glare and interference from bright or reflective objects, which can lead to inaccurate range measurements in complex environments, making them less reliable for navigation.
Innovation Solution
Encoding channel-specific information in light signals using techniques such as modulating pulse magnitudes or time delays between pulses, allowing the signal processing circuit to filter out-of-channel noise and improve signal quality by distinguishing intended signals from noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flash lidar illuminates the whole scene at once, then productivity is improved by parallel data collection, but measurement precision deteriorates due to out-of-channel noise and channel mixing false positives
Solution Approach 1:
The patent segments the illumination process by transmitting channel-specific light signals to different channels (spatial segments) at different times. Each channel receives a unique temporal code sequence, dividing the simultaneous illumination problem into sequential channel-specific illuminations while maintaining parallel detection capability across all channels.
Solution Approach 2:
The patent employs periodic pulse sequences transmitted to each channel, where each channel receives periodic light pulses with unique temporal patterns. This periodic action with distinct timing codes allows the receiver to distinguish signals from different channels through temporal correlation, enabling both parallel processing and precise measurement.
2Productivity
If flash lidar receives return signals from the whole scene at once, then productivity is improved, but reliability deteriorates due to channel mixing false positives
Solution Approach 1:
The patent applies preliminary action by pre-encoding unique temporal codes in the light signals transmitted to each channel before the return signals are received. This preliminary encoding allows the receiver to预先 know the expected temporal patterns for each channel, enabling it to distinguish genuine channel-specific returns from out-of-channel noise through temporal correlation.
Solution Approach 2:
The system implements feedback through temporal correlation processing, where the received signals are compared against the known transmitted code sequences. This feedback mechanism confirms whether detected signals match the expected temporal patterns for each channel, validating genuine returns and rejecting false positives from other channels.
3Ease of operation
If conventional flash lidar transmits light to multiple channels simultaneously, then ease of operation is improved, but measurement precision deteriorates due to glare from bright objects
Solution Approach 1:
The patent introduces dynamics by transitioning from static simultaneous illumination to dynamic sequential channel-specific illumination with unique temporal codes. This dynamic approach maintains the simplicity of flash lidar operation while improving signal-to-noise ratio through temporal discrimination, as the receiver can dynamically correlate received signals with the known time-varying code sequences for each channel.
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
Reduces the occurrence of CMFPs and enhances the reliability of flash lidar systems by accurately identifying and filtering out-of-channel noise, improving range measurement accuracy and reducing false positives.
Implementation Method 1
a lidar receiver that receives and processes incident light from a field of view, the lidar receiver comprising a pixel array, the pixel array comprising a plurality of pixels
Data Source
AI summary
Light detection and ranging (lidar) technology is capable of using light to measure the distance to objects in a field of view. A lidar system typically comprises a lidar transmitter, a lidar receiver, and a clock. The lidar transmitter transmits light into the field of view, and the light is reflected back to the lidar receiver after striking objects in the field of view. Techniques are described herein for encoding channel information into light transmissions so that the lidar receiver can use the encoded channel information to reduce the out-of-channel noise in channel-specific photodetection signals.