Micro Shutter Array Spatial Filtering for LiDAR Noise Reduction
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Solution Overview
Problem
In biaxial scanning LiDAR systems, a large receiving optics field of view (FOV) is necessary for detection range but also collects significant ambient light, which introduces noise and reduces detection accuracy, creating a trade-off between FOV and signal-to-noise ratio.
Innovation Solution
A micro shutter array is integrated into the receiver to filter out ambient light by sequentially opening only a portion of the array at specific locations, allowing optical signals to pass through while blocking most ambient light, thereby maintaining a high signal-to-noise ratio even with a large FOV.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the receiving optics FOV is increased to expand detection range, then the detection range is improved, but the signal-to-noise ratio deteriorates due to increased ambient light collection
Solution Approach 1:
The receiving optics FOV is segmented into multiple discrete angular positions corresponding to different scanning points. The micro shutter array segments the FOV into individually controllable zones, allowing selective opening of only those segments corresponding to active scan positions while keeping other segments closed to block ambient light.
Solution Approach 2:
The micro shutter array dynamically adjusts the effective FOV in real-time by sequentially opening and closing different shutter elements synchronized with the scanning beam positions. This dynamic control allows the system to maintain a large physical aperture while effectively limiting the instantaneous FOV to only those directions where return signals are expected.
2Area of stationary object
If the receiving optics FOV is increased to cover all scanned points, then the field of view is improved, but the ambient light collection increases
Solution Approach 1:
The micro shutter array divides the receiving optics FOV into multiple discrete angular zones, each corresponding to a specific scanning direction. Only the shutter elements corresponding to active scan positions are opened, while other elements remain closed to block ambient light from non-scanning directions.
Solution Approach 2:
The micro shutter array acts as an intermediary component between the large-aperture receiving optics and the photodetector. It mediates the conflict between collecting sufficient return signals and rejecting ambient light by selectively transmitting only those rays that correspond to valid return signals while blocking ambient light from other directions.
3Length of moving object
If the receiving optics aperture is made large to improve detection range, then the detection range is improved, but the ambient light noise increases
Solution Approach 1:
The micro shutter array segments the large aperture into multiple independently controllable zones, allowing the system to maintain the large physical aperture for collecting return signals while selectively blocking ambient light in non-scanning directions through closed shutter elements.
Solution Approach 2:
The system dynamically controls the micro shutter array elements in synchronization with the scanning beam positions. This dynamic control allows the large aperture to continuously track and collect return signals from moving targets while simultaneously rejecting ambient light from stationary background sources.
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 micro shutter array effectively increases the detection range of the LiDAR system without sacrificing accuracy by selectively allowing optical signals to pass through while blocking ambient light, enhancing the system's performance in real-world applications.
Implementation Method 1
a micro shutter array disposed in a light path of the returning series of optical signals and configured to sequentially open only a portion of the micro shutter array at a specified location at each time point, to allow the returned series of optical signals to sequentially pass through the micro shutter array
Data Source
AI summary
Embodiments of the disclosure provide a micro shutter array, an optical sensing system, and an optical sensing method. The optical sensing system includes a laser emitter configured to sequentially emit a series of optical signals and a steering device configured to direct the series of optical signals in different directions towards an environment surrounding the optical sensing system. The optical sensing system further includes a receiver configured to receive the series of optical signals returning from the environment. The receiver includes a micro shutter array disposed in a light path of the returning optical signals and configured to sequentially open only a portion of the micro shutter array at a specified location at each time point, to allow the returned series of optical signals to sequentially pass through the micro shutter array. The receiver further includes a photodetector configured to receive the optical signals sequentially passed through the micro shutter array.