3D shape acquisition using a combined SSD and least squares correlation approach

We want to present a new approach to 3D shape acquisition. This implementation enables the user to manually move the scan unit over the object without the scan unit being tracked. Registration from scan to scan is done on-the-fly to allow user interaction with the system. Since the user can watch the scene assembling gradually during the scan process he can immediately respond to occuring shadings due to shadows and undercuts. The chosen structured light scan approach uses an initially unknown white noise pattern that can easily be projected with any fixed pattern projection system. Object points are acquired on the basis of finding correspondences in the pattern in the camera image of the current scene. This is achieved by using a combination of a SSD and a least squares correlation algorithm. In the current test setup we are using a standard video beamer and a standard digital camera. Our approach reduces hardware complexity to a minimum using only one camera and a fixed pattern projector which both can be miniaturized. In this paper we want to present the whole system also including the calibration procedure. The focus will be on the correlation method.