Reference Line Pattern Detection for 3D Shape Measurement
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Solution Overview
Problem
Existing 3D shape measurement methods face errors when attempting to detect patterns in rough or narrow regions with insufficient vertical and horizontal plane areas, as they require continuous grid patterns for accurate 2D code pattern detection.
Innovation Solution
An information processing apparatus that includes reference line pattern detection and correspondence means to establish topological relationships between projected and captured line patterns, using reference line patterns with unique IDs and line widths to facilitate accurate 3D shape measurement even in non-sufficient plane areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a grid pattern with 2D code patterns is used for 3D shape measurement, then measurement precision is improved in sufficient plane areas, but pattern detection fails in rough or narrow regions with insufficient plane area
Solution Approach 1:
The patent segments the measurement task by separating reference line patterns from measurement line patterns. Reference line patterns (vertical and horizontal lines forming a grid) provide a stable structural framework that can be reliably detected even in rough or narrow regions, while measurement line patterns carry the actual 3D shape information. This segmentation allows the system to maintain reliable pattern detection through the reference grid while preserving measurement precision through the dedicated measurement patterns.
Solution Approach 2:
The reference line pattern acts as an intermediary between the projection system and the measurement process. By establishing a reliable topological relationship through the reference grid that can be detected in challenging regions, the system creates a stable reference framework that mediates the correspondence between projected and captured patterns, enabling accurate 3D measurement even where direct pattern detection would fail.
2Measurement precision
If continuous grid patterns are required for pattern detection, then measurement accuracy is maintained in sufficient areas, but the method becomes inapplicable to rough or narrow regions
Solution Approach 1:
The patent divides the pattern system into reference line patterns (forming a continuous grid structure) and measurement line patterns (carrying shape information). The reference line patterns provide the continuous grid structure needed for accurate correspondence establishment, while the segmented measurement patterns can be independently adapted to various surface conditions including rough and narrow regions, thereby increasing overall adaptability without sacrificing measurement accuracy.
Solution Approach 2:
Different regions of the pattern system serve different functions with different quality requirements. The reference line pattern region maintains continuous grid structure for accurate topological relationship establishment, while measurement line patterns in specific regions (rough or narrow areas) can be optimized locally for detection reliability, allowing the system to adapt to various surface conditions while maintaining overall measurement precision.
3Measurement precision
If 2D code patterns are embedded in grid rectangles for correspondence detection, then measurement precision is improved, but detection fails when grids cannot form sufficient rectangles
Solution Approach 1:
The patent extracts the correspondence detection function from the measurement line patterns and assigns it to the reference line patterns. By taking out the topological relationship establishment task from the measurement patterns and placing it in the reference grid, the system ensures reliable correspondence detection through the stable reference structure, while measurement patterns can focus on capturing shape information without the constraint of requiring sufficient rectangular areas for code embedding.
Solution Approach 2:
The reference line pattern serves as an intermediary structure that handles the correspondence detection function. The vertical and horizontal reference lines create a topological framework that mediates the matching between projected and captured patterns, providing reliable correspondence establishment independent of the measurement patterns' ability to form complete rectangles, thereby maintaining both precision and reliability.
Data Source
AI summary
A pattern light projection unit which stores information on pattern light including information on line patterns projects pattern light including line patterns having at least two lines and at least one reference line pattern serving as a reference of the line patterns on an object in accordance with the information on pattern light. An image pickup unit captures an image of the object to which the pattern light is projected.An information processing apparatus detects the reference line pattern and the line patterns from the captured image, and establishes correspondence between the information on the line patterns stored in the pattern light projection unit and the line patterns detected from the captured image in accordance with the topological positional relationship between the detected reference line pattern and the line patterns so as to identify the line patterns.