LIDAR Parallax Compensation via Angularly Offset Beam Scanning
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Solution Overview
Problem
LIDAR systems face challenges in accurately detecting objects due to noise from ambient light and parallax effects, which reduce detection accuracy and reliability, especially in environments with retroreflective objects and varying distances.
Innovation Solution
The method involves emitting multiple light beams with angular offsets across a detection range, allowing for repeated illumination of the same point and simultaneous evaluation of propagation times to improve detection accuracy and compensate for parallax effects, using a biaxial LIDAR system with divergent light beams and sensitive detectors to differentiate reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple light beams with angular offsets are transmitted to illuminate the same point multiple times, then detection accuracy is improved through averaging multiple distance measurements, but the time required for detection increases
Solution Approach 1:
The patent applies periodic action by transmitting multiple light beams in a sequential scanning manner, where each beam illuminates the detection range at different time instants. The beams are transmitted periodically with angular offsets, allowing multiple distance measurements to be taken at the same spatial location over time. This periodic transmission enables averaging of multiple measurements to improve detection accuracy while maintaining a controlled detection timeline.
2Reliability
If multiple light beams are transmitted sequentially with angular offsets, then parallax effects are compensated and detection reliability is improved, but the complexity of the detection system increases
Solution Approach 1:
The patent applies segmentation by dividing the detection process into multiple sequential steps, where different light beams with specific angular offsets are transmitted at different time instants. Each beam provides a segmented measurement that contributes to the overall detection result. This segmentation allows parallax effects to be compensated by comparing measurements from different angular perspectives while keeping the system implementation manageable through structured processing.
3Measurement precision
If the sensor is made highly sensitive to detect single photons, then detection capability is improved, but noise from ambient light increases
Solution Approach 1:
The patent applies feedback by evaluating hits using propagation times allocated to specific emission directions and comparing multiple distance measurements. The system uses the temporal information from multiple sequential measurements to distinguish true reflections from ambient light noise. By analyzing the consistency of propagation times across multiple beams and using statistical evaluation, the system can filter out noise while maintaining high sensitivity for detecting weak photon signals.
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 detection accuracy by averaging multiple distance measurements, reduces noise from ambient light, and effectively compensates for parallax effects, enabling reliable detection of objects across a wide range with improved signal-to-noise ratio and dynamic range.
Implementation Method 1
a distance to an object at which the reflection has taken place is ascertained based on a time period until a reflection of the light is detected
Implementation Method 2
light is transmitted into a detection range and a distance to an object at which the reflection has taken place
Data Source
AI summary
A method for detecting objects using a LIDAR system. The method includes emitting a first light beam scanning in a scanning direction in an emission direction at a first instant, allocating a first propagation time between the first transmission instant and a first receiving instant of a first reflection of the first light beam to the emission direction, emitting in the emission direction, an angle-resolved, further light beam scanning in the scanning direction and angularly offset from the first light beam, at a second transmission instant following the first emission instant, allocating a second propagation time between the second transmission instant and a second receiving instant of a second reflection of the second light beam to the emission direction, and evaluating hits using the propagation times allocated to the emission direction.