Handheld 3D Contour Detection Using Dual-View Triangulation
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Solution Overview
Problem
Existing methods for contactless three-dimensional contour detection require a large number of recordings due to extensive information projection, making them unsuitable for hand-held devices, particularly for intraoral or extraoral applications like tooth surface detection.
Innovation Solution
A device with a projector and a camera arrangement featuring two camera lenses with a common camera chip, using deflection mirrors for a folded beam path, allowing for precise triangulation even without precise knowledge of stripe pattern projection directions, and enabling manual handling with a compact design suitable for intraoral measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Gray code is projected onto the object together with the stripe pattern to enable triangulation, then three-dimensional contour detection is achieved, but a large number of recordings are required
Solution Approach 1:
The invention extracts only the essential stripe pattern information needed for triangulation, eliminating the need for additional Gray code projection. By using phase correlation of sinusoidal stripe patterns across two camera views, the system achieves 3D contour detection with fewer recordings, directly addressing the time loss issue while maintaining measurement precision.
2Measurement precision
If extensive information is projected onto the object to enable accurate triangulation, then three-dimensional contour detection precision is improved, but the device complexity increases
Solution Approach 1:
The invention merges the projector and dual-camera system into an integrated measuring head with a common coordinate system. By combining the projection optics with the two-camera arrangement and using phase correlation algorithms, the system achieves accurate triangulation without requiring separate complex subsystems, thereby reducing overall device complexity while maintaining precision.
3Ease of operation
If a compact device design is implemented for hand-held use, then ease of operation is improved, but measurement precision may be compromised
Solution Approach 1:
The invention nests the two camera systems and projector within a compact measuring head structure. By folding the optical paths and arranging components in a nested configuration, the system achieves a compact form factor suitable for hand-held operation while maintaining the geometric relationships necessary for precise triangulation and contour detection.
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 accurate and efficient contactless detection of three-dimensional contours with reduced recording requirements, allowing for precise measurement of steep surfaces and compact device design suitable for hand-held use.
Implementation Method 1
a projector with an imaging element and a projection lens for imaging a stripe pattern that can be generated on the imaging element
Implementation Method 2
a camera arrangement comprising two camera lenses for observing the object space from two different directions
Data Source
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AI summary
The invention relates to a device for the contactless detection of a three-dimensional contour, comprising a projector with an imaging element (1) and a projection lens (2) for depicting a stripe pattern that is generated on the imaging element (1) in an object space (3). The invention further comprises a camera arrangement for the surveillance of the object space (3) from two different directions, having two camera lenses (4). The projector and the camera arrangement are housed together in a measurement head that can be handheld. The invention further relates to a method for detecting a three-dimensional contour using said device.