The VIDEOMETRIC patent «3D geometry measurement of hollow ring, using axial stereovision with two opposite cameras" has been published recently.
Patent : "Hollow ring measurement" (in French)
This patent protects a fast and precise 3D measurement method for "hollow ring" objects, and by extension any "hollow shape".
A usage example can be the 3D digitization of the glass frame inner contour, a mandatory measurement for optical glass grinding, to fit the lens into the frame.
The optical principle consists in placing two cameras in opposition, on both sides of the ring.
Images are then handled thru VIDEOMETRIC 3D calculation to extract quickly,and with high precision, the inner contour 3D data.
System variant is using one real camera and one virtual camera, created with a mirror (flat, concave or convex) positioned opposite.
System benefits :