Three-dimensional measurement apparatus, processing method, and non-transitory computer-readable storage medium

A processing method for a three-dimensional measurement apparatus for calculating a position and an orientation of a target object, the method comprising:

• a step of acquiring a range image in which pixels represent distances from a target object;
• a step of acquiring approximate values indicating a position and an orientation of the target object;
• a step of selecting points corresponding to geometric features of a three-dimensional shape model of the target object;
• a step of projecting a plurality of selected points corresponding to the geometric features onto the range image based on the approximate values indicating the position and the orientation of the target object and imaging parameters at the time of imaging of the range image;
• a step of searching regions of predetermined ranges respectively from the plurality of projected points for geometric features on the range image which correspond to the geometric features of the three-dimensional shape model, and associating the geometric features with each other;
• and
• a step of calculating a position and an orientation of the target object using differences of distances on a three-dimensional space between the geometric features of the three-dimensional shape model and the geometric features on the range image, which are associated with each other.

A non-transitory computer-readable storage medium storing a computer program for controlling a computer incorporated in a three-dimensional measurement apparatus for calculating a position and an orientation of a target object, to function as:

• an image acquisition unit configured to acquire a range image in which pixels represent distances from a target object;
• an approximate value acquisition unit configured to acquire approximate values indicating a position and an orientation of the target object;
• a selection unit configured to select points corresponding to geometric features of a three-dimensional shape model of the target object;
• a projection unit configured to project a plurality of points corresponding to the geometric features selected by said selection unit onto the range image based on the approximate values indicating the position and the orientation of the target object and imaging parameters at the time of imaging of the range image,
• a search unit configured to search regions of predetermined ranges respectively from the plurality of projected points for geometric features on the range image which correspond to the geometric features of the three-dimensional shape model, and associate the geometric features with each other;
• and
• a position/orientation calculation unit configured to calculate a position and an orientation of the target object using differences of distances on a three-dimensional space between the geometric features of the three-dimensional shape model and the geometric features on the range image, which are associated with each other by said search unit.