Lidar Sensor Pulse Rate Modulation for 360-Degree Field Stitching
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Solution Overview
Problem
Existing vehicle sensing systems face challenges in achieving a seamless and accurate combination of sensing fields from multiple lidar sensor modules due to mounting tolerances and gaps, which can lead to incomplete coverage and misalignment, especially when aiming for a 360-degree field of sensing.
Innovation Solution
The system employs multiple lidar sensor modules with unique laser units that transmit different patterns in overlap and non-overlap areas, allowing the control unit to detect pattern differences and spatially synchronize the data, minimizing overlap and ensuring accurate stitching of the combined field of sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple lidar sensor modules are used to achieve comprehensive coverage, then the field of sensing is improved, but gaps and misalignments occur due to mounting tolerances
Solution Approach 1:
The patent applies pattern modulation (analogous to color changes) by varying laser pulse characteristics (pattern) in different spatial regions. Each lidar module transmits a unique pattern in overlap areas, enabling the control unit to detect and identify corresponding features across modules, thereby achieving accurate spatial synchronization and stitching despite mounting tolerances.
Solution Approach 2:
The patent introduces pattern differences as an intermediary element that mediates between the physical gap/misalignment caused by mounting tolerances and the requirement for accurate spatial registration. The control unit uses these pattern differences as reference markers to calculate and compensate for positional offsets, enabling precise alignment without requiring perfect mechanical mounting.
2Reliability
If lidar sensor modules are positioned to minimize gaps, then coverage completeness is improved, but misalignment in overlap areas increases
Solution Approach 1:
The patent applies local quality by transmitting different laser patterns specifically in overlap areas versus non-overlap areas. This localized differentiation enables the control unit to identify and process only the overlapping regions with the correct pattern, facilitating accurate spatial registration while maintaining comprehensive coverage through the strategic placement of multiple sensors.
3Adaptability or versatility
If a 360-degree field of sensing is implemented, then object detection capability is improved, but system complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the 360-degree sensing field into multiple regions covered by separate lidar sensor modules. Each module handles a specific sector, and the control unit integrates these segmented views into a complete 360-degree representation. The pattern modulation provides a consistent reference across segments, simplifying the integration process while maintaining comprehensive object detection capability.
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 enables a comprehensive and accurate 360-degree field of sensing by minimizing gaps and misalignments, enhancing the system's ability to detect objects and provide reliable data for driver assistance and autonomous vehicle control.
Implementation Method 1
Each lidar sensor module includes a laser unit and a sensor unit. Each lidar sensor module has a field of sensing that is different than the other fields of sensing
Implementation Method 2
Each laser unit may transmit a pattern in overlap areas that is different from patterns transmitted in a non-overlap area
Data Source
AI summary
A vehicular driving assist system includes a plurality of lidar sensors having respective fields of sensing exterior the vehicle. The lidar sensors emit light pulsed at a respective pulse rate and provide a respective output to an electronic control unit based on sensed light that is reflected by objects present in the field of sensing of the respective lidar sensor. The pulse rates of light emitted by the lidar sensors are different. The vehicular driving assist system, via processing at the ECU of the outputs from the lidar sensors, generates a three dimensional (3D) point cloud. The vehicular driving assist system controls the vehicle based at least in part on light sensed by the lidar sensors that is reflected by the objects when light is emitted by the lidar sensors at the respective pulse rates.