Dynamic SPAD Array Active Area Selection for LIDAR Noise Reduction
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Solution Overview
Problem
LIDAR receivers are vulnerable to noise from sources of light other than the LIDAR transmitter, which degrades the signal-to-noise ratio and affects the accuracy of distance measurement in LIDAR systems, especially in environments with multiple LIDAR systems operating in close proximity.
Innovation Solution
An optical sensor using a two-dimensional array of single photon avalanche devices (SPADs) with row-select and column-select transistors, allowing for dynamic adjustment of the active area based on the predicted spot size and angle of the reflected laser light, thereby reducing noise and eliminating the need for moving parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor active area is increased to capture more reflected laser light, then the signal strength is improved, but the noise from other light sources increases
Solution Approach 1:
The sensor array is divided into multiple independently controllable sensor elements arranged in a grid pattern, allowing selective activation of only those elements that correspond to the expected location of reflected laser light. This segmentation enables the system to capture sufficient signal while excluding noise from other light sources by keeping non-relevant sensor elements inactive.
Solution Approach 2:
The system dynamically adjusts the active sensor elements based on real-time predictions of laser beam location and spot size. By continuously updating which sensor elements are activated according to the predicted reflected light position, the system maintains optimal signal capture while adapting to changing conditions and minimizing noise exposure.
2Object-affected harmful factors
If moving parts are added to adjust the sensor active area, then the noise reduction capability is improved, but the device complexity increases
Solution Approach 1:
The patent replaces mechanical adjustment mechanisms with an electronic control system that selectively activates sensor elements through electrical signals. Instead of physically moving parts to change the active area, the system uses electronic switching to enable or disable specific sensor elements, thereby reducing noise while avoiding the complexity and reliability issues associated with moving parts.
3Measurement precision
If the active area is dynamically adjusted, then the signal-to-noise ratio is improved, but the control system complexity increases
Solution Approach 1:
The system performs preliminary calculations to predict the location and spot size of reflected laser light before actively scanning begins. By pre-determining which sensor elements will be needed based on expected target positions and beam characteristics, the control system can efficiently activate only the necessary sensors, reducing the overall control complexity while maintaining high signal-to-noise ratios.
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 the signal-to-noise ratio by selectively activating only the SPADs expected to be illuminated by the reflected laser beam, leading to more accurate LIDAR functionality and improved noise reduction without the need for moving parts in the LIDAR receiver.
Implementation Method 1
an array of single photon avalanche devices (SPADs)... Each SPAD may have... a photo detection element
Implementation Method 2
single photon avalanche devices (SPADs)... Each SPAD may comprise an avalanche photodiode (APD)
Data Source
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AI summary
Techniques provided herein are directed toward providing an optical sensor that reduces noise from sources of light other than the LIDAR transmitter by changing the active area of the sensor of a LIDAR receiver. The optical sensor may include a two dimensional array of single photon avalanche devices (SPADs) with rowselect and column-select transistors, where rows and columns are selected based on a predicted spot size and angle of reflected laser light detected at the LIDAR receiver. Among other things, this can eliminate or reduce the need for moving parts within the LIDAR receiver.