Method and apparatus for determining at least one of dimensional or geometric characteristics of a measurement object

An apparatus for determining at least one of dimensional or geometric characteristics of a measurement object, comprising:

• a first measurement arrangement for determining 3D coordinates at first selected measurement points of the measurement object,
• a second measurement arrangement for determining surface normals at second selected measurement points of the measurement object, wherein the second measurement arrangement includes a number of light sources and a first camera which is directed to the measurement object, and
• an evaluation and control unit comprising a calibration data set that represents individual direction dependent radiation patterns of the light sources and configured for
• determining the 3D coordinates at the first selected measurement points using the first measurement arrangement, the 3D coordinates defining first measurement results,
• determining the surface normals at the second selected measurement points using the second measurement arrangement and using the calibration data set and the first measurement results, the surface normals thus determined defining second measurement results,
• determining the at least one of dimensional or geometric characteristics of the measurement object using the first and second measurement results.

A computer program product comprising program code stored on a nontransitory storage medium, the program code configured to execute a method for determining at least one of dimensional or geometric characteristics of a measurement object using a first measurement arrangement for determining 3D coordinates at first selected measurement points of the measurement object and using a second measurement arrangement for determining surface normals at second selected measurement points of the measurement object, wherein the second measurement arrangement includes a number of light sources and a first camera which is directed to the measurement object, the method comprising the steps of:

• providing a calibration data set representing individual radiation patterns of the light sources,
• determining 3D coordinates at the first selected measurement points using the first measurement arrangement, the 3D coordinates defining first measurement results,
• determining surface normals at the second selected measurement points using the second measurement arrangement and using the calibration data set and the first measurement results, the surface normals thus determined defining second measurement results, and
• determining the at least one of dimensional or geometric characteristics of the measurement object using the first and the second measurement results.