3D Model Creation Using Asymmetric Reference Mark
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Solution Overview
Problem
Existing methods for creating three-dimensional models using stereo measurement struggle with accuracy, particularly when dealing with objects featuring chamfered portions, curved surfaces, and symmetrical structures, leading to misalignment and increased costs due to the need for precise equipment like rotary tables.
Innovation Solution
A method involving the use of a mark with a shape without rotational symmetry, attached to the object, which is imaged multiple times with cameras having fixed positions, allowing for accurate alignment and integration of three-dimensional information through coordinate transformation, ensuring high coincidence degrees and reducing user burden.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the method of aligning three-dimensional information from unknown observation directions is used, then the three-dimensional model can be created without precise equipment like rotary tables, but the alignment accuracy becomes difficult to ensure leading to misalignment
Solution Approach 1:
A mark with asymmetric shape is introduced as an intermediary reference object attached to the target object. This mark serves as a mediator between the unknown observation directions, providing distinctive geometric features that enable accurate correspondence and alignment of three-dimensional information without requiring precise equipment or complex calculations
Solution Approach 2:
The mark is designed with specific visual characteristics (asymmetric shape, distinct color or pattern) that make it easily distinguishable in stereo images. These visual properties enable reliable detection and correspondence of the mark across different viewing angles, facilitating accurate alignment of three-dimensional data from multiple observation directions
2Adaptability or versatility
If multiple stereo measurements are performed from various directions to create an integrated three-dimensional model, then the model can represent objects with fixed and variable position/orientation, but the correspondence accuracy between measurements becomes difficult to ensure
Solution Approach 1:
The asymmetric mark attached to the target object serves as a stable intermediary reference that remains consistent across multiple stereo measurements from different directions. By corresponding this mark in each measurement, the system achieves accurate alignment between measurements without requiring complex calculations or precise knowledge of observation directions
Solution Approach 2:
The mark is deliberately designed with asymmetric geometry that lacks rotational symmetry. This asymmetry ensures that the mark appears differently from various observation directions, providing unique geometric features that enable unambiguous correspondence and accurate alignment of three-dimensional information across multiple measurements
3Adaptability or versatility
If the coincidence degree is calculated by arbitrarily changing positional relationships, then multiple correspondence relationships can be evaluated, but the final alignment accuracy remains insufficient
Solution Approach 1:
The asymmetric shape of the mark provides distinctive geometric features that create a clear maximum in the coincidence degree calculation. When the mark is correctly corresponded, the coincidence degree reaches its maximum value, making it easy to identify the correct alignment among multiple candidates without requiring arbitrary changes in positional relationships
Data Source
AI summary
A polygonal mark M having a shape in which a direction can be uniquely specified is attached to a predetermined area of an actual model WM of a work to be three-dimensionally recognized. A process of changing the orientation of the actual model WM such that a state in which the mark M is contained in the view of each camera is maintained, and then performing the three-dimensional measurement is executed over a plurality of times. A predetermined number of, or two or more pieces of three-dimensional information is selected from the three-dimensional information restored by each measurement, these pieces of three-dimensional information are aligned and integrated, the information corresponding to the mark is deleted or invalidated from the integrated three-dimensional information, and the three-dimensional information after such a process is set as a three-dimensional model.