Active Sensor Dithering for Retroreflector Cross-Talk Mitigation
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Solution Overview
Problem
Active sensors like LIDAR experience cross-talk errors due to spurious signal detections from retroreflectors, which interfere with the accurate detection of objects in the environment, leading to unreliable object detection and potential safety issues in applications such as vehicle navigation.
Innovation Solution
The implementation of a multi-channel active sensor system where emitters emit light pulses at different time offsets during a scan, allowing spurious signals to be mapped over a range of distances, and adjusting these offsets in subsequent scans to ensure coherent detection of actual objects, thereby mitigating cross-talk errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple emitters illuminate different portions of the FOV simultaneously, then the scanning coverage and productivity are improved, but cross-talk errors from retroreflectors increase due to spurious signal detections
Solution Approach 1:
The patent divides the field-of-view into multiple portions, each illuminated by a separate emitter. Each emitter is assigned a unique time offset within the emission time period, creating segmented temporal channels that prevent cross-talk between emitters while maintaining simultaneous spatial coverage.
Solution Approach 2:
The patent dynamically adjusts the time offsets of emitters based on detected cross-talk conditions. When retroreflector interference is detected, the system modifies the temporal positioning of emitter signals to eliminate spurious detections, adapting the scanning pattern in real-time to maintain detection accuracy.
2Ease of operation
If emitters use fixed time offsets, then the system operation is simple and reliable, but spurious signals from retroreflectors cannot be distinguished from actual object signals
Solution Approach 1:
The patent implements periodic scanning with varying time offsets across multiple emission time periods. By systematically changing the temporal pattern of emitter activation in a periodic manner, the system creates distinctive signal signatures that allow differentiation between genuine object reflections and retroreflector spurious signals.
Solution Approach 2:
The system incorporates feedback mechanisms where detected signals are analyzed to identify patterns consistent with retroreflector interference. Based on this feedback, the controller adjusts emitter time offsets to eliminate ambiguous detections, creating a closed-loop system that continuously improves measurement precision.
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 improves the accuracy of object detection by distinguishing between actual and spurious signals, reducing the impact of retroreflector-induced errors and enhancing the reliability of active sensors in scanning environments.
Implementation Method 1
The first emitter emits light that illuminates a first portion of a field-of-view (FOV) of the device. The second emitter emits light that illuminates a second portion of the FOV.
Implementation Method 2
detecting reflections of the emitted signals
Implementation Method 3
determining a distance to the object according to a time delay between the transmission of the pulse and the reception of the reflected pulse
Data Source
AI summary
One example device comprises a plurality of emitters including at least a first emitter and a second emitter. The first emitter emits light that illuminates a first portion of a field-of-view (FOV) of the device. The second emitter emits light that illuminates a second portion of the FOV. The device also comprises a controller that obtains a scan of the FOV. The controller causes each emitter of the plurality of emitters to emit a respective light pulse during an emission time period associated with the scan. The controller causes the first emitter to emit a first-emitter light pulse at a first-emitter time offset from a start time of the emission time period. The controller causes the second emitter to emit a second-emitter light pulse at a second-emitter time offset from the start time of the emission time period.