Aperiodic Sinusoidal Stripe Pattern for Fast 3D Surface Measurement
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Solution Overview
Problem
Existing methods for contact-free three-dimensional surface contour measurement require a large number of patterns and images to be projected and captured, leading to lengthy measurement durations, which is disadvantageous for applications involving moving surfaces or handheld devices.
Innovation Solution
A method utilizing aperiodic sinusoidal strip patterns projected onto a surface, where sequences of brightness values are detected and correlated to rapidly identify corresponding points, allowing for accurate triangulation and spatial coordinate determination with significantly reduced measurement time, even with a single camera or using two cameras.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of strip patterns are projected to achieve accurate identification of corresponding points, then measurement precision is improved, but measurement duration increases
Solution Approach 1:
The patent employs periodic sinusoidal strip patterns with varying phases to encode surface information. By projecting multiple phase-shifted sinusoidal patterns and analyzing the phase information, the system can identify corresponding points with high precision using fewer patterns compared to traditional binary coding methods, thus reducing measurement duration while maintaining accuracy
Solution Approach 2:
The patent changes the phase parameter of sinusoidal strip patterns to encode different surface position information. By varying the phase shift between projected patterns and analyzing the phase differences in captured images, the system achieves accurate 3D reconstruction with reduced number of patterns, resolving the contradiction between precision and measurement time
2Measurement precision
If multiple pictures are captured to ensure unambiguous identification of corresponding points, then measurement accuracy is improved, but productivity decreases
Solution Approach 1:
The use of periodic sinusoidal patterns with different phase shifts allows the system to capture multiple surface position encodings in a small number of pictures. The phase information from these periodic patterns provides unambiguous corresponding point identification, achieving high measurement accuracy while minimizing the number of required captures, thus improving productivity
Solution Approach 2:
The patent uses phase-shifted sinusoidal patterns as information carriers that encode surface geometry data. Each pattern captures a different aspect of the surface information, and by combining these phase-encoded copies, the system reconstructs the complete 3D surface contour with high accuracy using fewer pictures, thereby increasing measurement speed
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
Enables high-accuracy, contact-free measurement of three-dimensional surfaces with extremely short measuring times, reducing the number of required camera recordings and allowing for stable measurement of complex geometries with rapid picture change rates.
Implementation Method 1
a sequence of strip patterns of the same strip direction which are formed in each case from a multitude of strips is projected by way of a projecting device onto a surface to be measured
Implementation Method 2
A sequence of brightness values is detected for each of the points, on the basis of which the triangulation is to take place, by way of taking (recording) the pictures during the projecting of the strip patterns
Data Source
AI summary
Method and device for non-contact measuring of surface contours. A sequence of stripe patterns, formed from a plurality of stripes of equal stripe direction are projected on a surface to be measured, wherein the stripe patterns are each aperiodic and have a sinusoidal brightness distribution and wherein, during the projecting of each of the stripe patterns, at least one image of the surface is captured by at least one camera. By the stripe pattern projected on the surface, corresponding points in the image planes of a camera and of a projection device used for projecting, or in the image planes of the cameras, are then identified by maximizing a correlation between sequences of brightness values recorded for each of the points, whereupon spatial coordinates of surface points on the surface are determined via triangulation on the basis of points identified as corresponding.