3D Measurement System Using Combined Pattern for Stereo Matching
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Solution Overview
Problem
Stereo matching methods for 3D measurement face challenges in achieving high-speed and high-accuracy processing due to the increased time required for searching corresponding points in high-resolution images.
Innovation Solution
A three-dimensional measurement system that uses a combined pattern of spatially encoded and random patterns, where the spatially encoded pattern includes regularly arranged unit elements corresponding to depth values and the random pattern adds complexity to the image features, allowing for a narrowed search range based on predicted parallax, thereby enhancing the accuracy and speed of stereo matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-resolution cameras are used to increase measurement points and accuracy, then measurement precision is improved, but processing time increases significantly due to longer search time for corresponding points
Solution Approach 1:
The patent applies preliminary action by first performing spatially encoded pattern measurement to obtain initial depth information before conducting stereo matching. This preliminary depth information is used to predict parallax and define restricted search ranges, thereby preparing the search process in advance and reducing the time required for corresponding point search in high-resolution images
Solution Approach 2:
The patent segments the measurement process into two stages: first using spatially encoded pattern technique to obtain coarse depth information, then using stereo matching with restricted search ranges based on predicted parallax. This segmentation allows the system to handle high-resolution images efficiently by dividing the complex task into manageable steps
2Productivity
If the search range for corresponding points is restricted to reduce processing time, then productivity is improved, but measurement precision may deteriorate due to limited search area
Solution Approach 1:
The patent uses feedback by incorporating spatially encoded pattern measurement results to inform and guide the subsequent stereo matching process. The predicted parallax from the first measurement stage provides feedback that defines the search ranges for the second stage, ensuring that the restricted search areas are based on accurate preliminary information
Solution Approach 2:
The system performs preliminary depth estimation using spatially encoded patterns before conducting stereo matching. This preliminary action establishes accurate search ranges that maintain measurement precision while restricting the search area to improve processing speed
3Productivity
If spatially encoded pattern technique is used to achieve high-speed measurement, then productivity is improved, but measurement precision deteriorates due to low spatial resolution
Solution Approach 1:
The patent merges two measurement techniques: spatially encoded pattern measurement and stereo matching. The system combines the speed advantage of spatially encoded patterns with the high precision of stereo matching by using the former to guide the search process in the latter, achieving both high speed and high precision simultaneously
Solution Approach 2:
The measurement process is segmented into two complementary stages: spatially encoded pattern measurement for rapid initial depth estimation, and stereo matching with restricted search ranges for high-precision final measurement. This segmentation allows each method to contribute its strengths to the overall system performance
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 system achieves high-accuracy and high-speed 3D measurement with high spatial resolution by limiting the search ranges for corresponding points and increasing the complexity of image features, balancing processing time and success rate.
Implementation Method 1
a projector configured to project patterned light onto a target object
Implementation Method 2
a first camera configured to image the target object, a second camera configured to image the target object from a viewpoint different from the first camera
Implementation Method 3
Based on the pattern position, 3D information (e.g., depth information for each pixel) is obtained using the principle of triangulation
Implementation Method 4
a definer configured to define a search range for a corresponding point for stereo matching based on parallax between the first image and the second image predicted from the first depth information
Data Source
AI summary
A three-dimensional measurement system projects patterned light onto a target object, images the target object from different viewpoints to obtain a first image and a second image, obtains first depth information using the first image with a spatially encoded pattern technique, defines a search range for a corresponding point based on parallax between the first image and the second image predicted from the first depth information, and obtains second depth information by performing stereo matching for the defined search range using the first image and the second image. The second depth information has a higher spatial resolution than the first depth information. The patterned light has a combined pattern combining a spatially encoded pattern including a plurality of unit elements arranged regularly and a random pattern including a plurality of random pieces arranged randomly. Each of the plurality of unit elements is an area corresponding to a depth value.