Patent ID: 6327380
Filing Date: 2001-12-04
Classification: G01B

Abstract:
A method for correlating three-dimensional measurements taken by at least a first (I) and a second (II) optical image-acquisition system, the method including a calibration phase comprising the steps of:providing a reference system including a sphere mounted so as to move in rotation in a plane about a first axis spaced from and different than a second axis passing through a center of the sphere;placing the at least first and second optical image-acquisition system in an arcuate relationship spaced from one another along a circle which is perpendicular to said first axis and which circle has a center aligned with said first axis;displacing the sphere by successive partial rotations in the plane about the first axis in order to place the sphere in at least first (a) and second (b) measurement positions which are visible simultaneously by the two optical image-acquisition systems;displacing the sphere by partial rotation in the plane about the first axis in order to place it in at least one measurement position (c), which is visible by at least the first optical image-acquisition system (I) and is different than the first and second measurement positions;displacing the sphere by rotation in the plane about the first axis in order to place it in at least one measurement position (d), which is visible by at least the second optical image-acquisition system (II) and is different than the first and second measurement positions;measuring, for each of the measurement positions, a surface of the sphere seen by each of the optical image-acquisition systems;determining, for each of the measurement positions, the center of the sphere seen by each of the optical image-acquisition systems; determining and expressing the reference system in a first coordinate frame as seen by the first optical image-acquisition system, and determining and expressing in a second coordinate frame the reference system as seen by the second optical image-acquisition system; andcalculating a matrix of the transformation between the first and second coordinate frames, in order to make a correlation between the measurements of the first and second optical image-acquisition systems.