Line Scanner Photosensor Processing for Multipath Interference
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Solution Overview
Problem
Existing laser line probes (LLPs) face challenges in capturing data at high speeds without compromising accuracy or sensitivity, and struggle to reliably detect and remove 3D coordinates incorrectly determined due to multipath interference.
Innovation Solution
The method involves projecting a line of light onto an object, capturing images with a camera using alternating exposure times for odd and even rows of a photosensitive array, and adjusting window subregions to improve dynamic range and eliminate spurious points caused by multipath reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the camera captures images at high speed to improve measurement productivity, then the exposure time is reduced, but the dynamic range and sensitivity are compromised
Solution Approach 1:
The photosensitive array is divided into multiple regions of interest (ROIs), and different exposure times are applied to different row groups within these regions. This segmentation allows simultaneous optimization of exposure time for different parts of the image, capturing both bright and dark features with appropriate exposure levels, thereby maintaining dynamic range while enabling high-speed data capture.
Solution Approach 2:
The system dynamically adjusts exposure times for different row groups based on the captured image data. By analyzing the intensity distribution and identifying multipath interference patterns, the system adapts the exposure parameters in real-time, allowing high-speed capture while preserving measurement accuracy and dynamic range through adaptive exposure control.
2Measurement precision
If the camera uses longer exposure time to improve sensitivity and dynamic range, then the measurement speed decreases
Solution Approach 1:
The photosensitive array is divided into multiple regions of interest (ROIs), and different exposure times are applied to different row groups within these regions. This segmentation allows simultaneous optimization of exposure time for different parts of the image, capturing both bright and dark features with appropriate exposure levels, thereby maintaining dynamic range while enabling high-speed data capture.
Solution Approach 2:
The system processes multiple row groups in parallel with different exposure times, ensuring continuous data capture without idle time. By overlapping the processing of different exposure groups and maintaining continuous scanning, the system achieves high measurement speed while preserving sensitivity through multi-exposure capture.
3Reliability
If the system captures all pixel data to ensure complete object surface coverage, then the data processing complexity increases
Solution Approach 1:
The system extracts and processes only the relevant regions of interest (ROIs) from the captured images, rather than processing the entire photosensitive array. By identifying and isolating the specific row groups containing object surface information, the system reduces data processing complexity while maintaining complete surface coverage through targeted ROI selection and processing.
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 speed and accuracy of 3D measurements by improving dynamic range and effectively removing errors from multipath interference, allowing for more precise data capture.
Implementation Method 1
light from an LLP may reflect off a first portion of a surface an intersect a second portion of the surface before returning to the LLP camera
Implementation Method 2
capturing with the camera a first image of the first line of light on the object within a first window subregion of the photosensitive array
Data Source
AI summary
A method includes providing a measuring device having a projector, a camera with a photosensitive array, and at least one processor, projecting with the projector a line of light onto an object, capturing with the camera an image of the projected line of light on the object within a window subregion of the photosensitive array, and calculating with the at least one processor three-dimensional (3D) coordinates of points on the object based at least in part on the projected line of light and on the captured image.