3D Imaging Using Grayscale-Guided LiDAR Saturation Correction
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Solution Overview
Problem
LiDAR systems face issues with sensor saturation due to high sensitivity of single-photon avalanche diodes (SPADs) and stray light, leading to blind spots and incorrect object identification, particularly in autonomous vehicles.
Innovation Solution
A two-stage measurement process involving capturing a grayscale image of the field of view followed by determining time delay of reflected radiation, using the grayscale image to correct for saturation and stray light, and forming a three-dimensional image from both images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor is made highly sensitive to detect reflected radiation, then the detection capability is improved, but sensor saturation occurs leading to blind spots
Solution Approach 1:
The sensor array is divided into multiple independently controllable sensing elements (pixels), allowing selective activation of specific regions. When saturation is detected in one area, other regions can continue operating, eliminating blind spots while maintaining high sensitivity where needed.
Solution Approach 2:
The LiDAR system dynamically adjusts the activation state of sensing elements based on real-time conditions. The controller can selectively activate or deactivate specific pixels to prevent saturation while maintaining detection capability in other areas, making the system adaptive to varying radiation intensities.
2Quantity of substance
If the sensor operates continuously to capture all reflected radiation, then the coverage is improved, but stray light interference increases leading to incorrect object identification
Solution Approach 1:
The system performs preliminary detection using a subset of sensing elements or lower intensity radiation before full measurement. This preliminary action identifies the presence and position of objects, allowing the system to then focus measurement resources only on relevant areas, reducing stray light exposure while maintaining comprehensive coverage.
Solution Approach 2:
Different regions of the sensor array are activated with different intensities or timing based on local conditions. Areas with high stray light interference can be measured with lower intensity or delayed activation, while clear areas use full sensitivity, optimizing the balance between coverage and interference reduction.
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 method effectively avoids sensor saturation and corrects for stray light, ensuring reliable three-dimensional image formation without loss of range or performance, reducing blind spots and improving object detection accuracy.
Implementation Method 1
a sensor operable to measure a portion of the emitted radiation that is reflected from objects disposed in the field of view
Implementation Method 2
The focusing optics may be arranged to focus radiation received from the solid angle element of each pixel to a different region in a plane of the sensor
Data Source
AI summary
A method of forming a three-dimensional image includes, first, capturing a first image of a field of view and then, subsequently, capturing range information. The method further includes forming the three-dimensional image, wherein the three-dimensional image is dependent on the first image. Capturing the first image of a field of view includes: illuminating the field of view with radiation; and determining an intensity of each of a plurality of pixels of reflected radiation from the field of view. Capturing the range information includes: illuminating the field of view with radiation; and determining a time delay of reflected radiation from the field of view for each of a plurality of pixels.