| 摘要 |
There is provided a method for obtaining three-dimensional surface points of an object in an object coordinate system having two groups of steps. The method first comprises providing a set of target positioning features on the object. In a first group of steps, acquiring at least a pair of 2D first images of the object, at least a first portion of the set of target positioning features being apparent on the pair of first images, extracting, from the 2D first images, at least two first sets of 2D positioning features from a reflection of the target positioning features of the first portion on the surface; calculating a first set of calculated 3D positioning features in the sensing device coordinate system using the first sets of 2D positioning features; computing first transformation parameters for characterizing a current spatial relationship between the sensing device coordinate system and the object coordinate system, cumulating the first set of transformed 3D positioning features to provide and augment the set of reference 3D positioning features. In a second group of steps, providing a projected pattern on a surface of the object using a pattern projector; acquiring at least a pair of 2D second images of the object by the cameras, the projected pattern and at least a second portion of the set of target positioning features being apparent on the pair of second images, extracting, from the 2D second images, at least one set of 2D surface points from a reflection of the projected pattern on the surface, and at least two second sets of 2D positioning features from a reflection of the target positioning features of the second portion on the surface; calculating a set of 3D surface points in the sensing device coordinate system using the set of 2D surface points; calculating a second set of calculated 3D positioning features in the sensing device coordinate system using the second sets of 2D positioning features; computing second transformation parameters for characterizing a current spatial relationship between the sensing device coordinate system and the object coordinate system, transforming the set of 3D surface points into a set of transformed 3D surface points in the object coordinate system using the second transformation parameters.
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