Non-contact method and system for building CAD models by integrating high density data scans
First Claim
1. A method of building a CAD model which represents an object positioned at a scanning station, the method comprising the steps of:
- a) generating reference data relating to a surface of the object to be scanned, the surface including at least one reference feature of the object, the at least one reference feature having a boundary;
b) scanning the surface of the object at the scanning station based on the reference data to generate reflected signals;
c) converting the reflected signals to corresponding electrical signals;
d) computing scan data based on the electrical signals;
e) determining at least a portion of the boundary of the at least one reference feature based on the scan data to obtain boundary data;
f) determining the location of at least one reference feature of the object in a local coordinate system based on the boundary data;
g) repeating steps a)-f) for another surface of the object to obtain the location of the at least one reference feature in a second local coordinate system different from the first local coordinate system;
h) comparing the locations of the at least one reference feature in the coordinate systems to obtain a transform;
i) mapping the scan data into a global coordinate system based on the transform; and
j) integrating the scan data in the global coordinate system to obtain a CAD model of the object.
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Accused Products
Abstract
Method and system are provided which permits the very precise integration of high density data scans obtained from different part orientations through the use of Horn'"'"'s method. The data may be obtained from a laser scanner or other methods for obtaining high density data such as Moire interferometry systems. The method and system use an artificial intelligence technique which permits the very precise determination of the dimensions of analytic features. In the preferred embodiment, the method uses a laser scanner to collect a fine grid of height (z) values of the workpiece. The part is scanned along lines with constant x or constant y. Before the part is scanned, several small reference features are added to the part if needed. These reference features may be small pieces of tape, or small metal washers. Then methods are used to find the precise location of the centers of the reference features. These locations provide the necessary input to Horn'"'"'s method so local coordinate systems for each scan can be mapped to a single global coordinate system.
54 Citations
17 Claims
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1. A method of building a CAD model which represents an object positioned at a scanning station, the method comprising the steps of:
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a) generating reference data relating to a surface of the object to be scanned, the surface including at least one reference feature of the object, the at least one reference feature having a boundary; b) scanning the surface of the object at the scanning station based on the reference data to generate reflected signals; c) converting the reflected signals to corresponding electrical signals; d) computing scan data based on the electrical signals; e) determining at least a portion of the boundary of the at least one reference feature based on the scan data to obtain boundary data; f) determining the location of at least one reference feature of the object in a local coordinate system based on the boundary data; g) repeating steps a)-f) for another surface of the object to obtain the location of the at least one reference feature in a second local coordinate system different from the first local coordinate system; h) comparing the locations of the at least one reference feature in the coordinate systems to obtain a transform; i) mapping the scan data into a global coordinate system based on the transform; and j) integrating the scan data in the global coordinate system to obtain a CAD model of the object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 16)
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9. A system for building a CAD model which represents an object positioned at a scanning station, the system comprising:
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means for generating reference data relating to surfaces of the object to be scanned, each of the surfaces including at least one reference feature of the object, the at least one reference feature having a boundary; means for scanning the surfaces of the object at the scanning station based on the reference data to generate reflected signals; means for converting the reflected signals to corresponding electrical signals; means for computing scan data based on the electrical signals; means for detecting at least a portion of the boundary of the at least one reference feature based on the scan data to obtain boundary data; means for determining the locations of at least one reference feature of the object in local coordinate systems based on the boundary data; means for comparing the locations of the at least one reference feature within each of the local coordinate systems to obtain a transform; means for mapping the scan data into a global coordinate system based on the transform; and means for integrating the scan data in the global coordinate system to obtain a CAD model of the object. - View Dependent Claims (10, 11, 12, 13, 14, 15, 17)
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Specification