Estimation of 3-d Deformation from One or More Images with Weak Imaging Geometry

The paper proposes a new method for estimation of 3-D deformation of an object from a single image or from multiple images in fixed positions with weak imaging geometry. It is assumed that the 3-D coordinates of the object points before deformation and the 2-D image coordinates after deformation are available and the interior and exterior orientations of the images are known. The core of the method is to approximate the 3-D deformation by a suitable shape function containing parameters the values of which are estimated during adjustment. Experimental results prove high accuracy and fast computing time of the proposed method in cases where the traditional method fails. The proposed method is mainly intended for applications where restrictions set by the measurement environment hinder obtaining strong imaging geometry and where some knowledge of the type of deformation that is likely to occur is available.