A multi-scale analysis for the characterization of 3D objects

In this paper, we present a method for performing a multi-scale analysis by using the B-Spline wavelet transform applied on 3D objects containing relevant information at different scales. An accurate non-contact optical system based upon laser triangulation has been used to determine depth information of objects. The resulting range image is treated as a gray-level image by using a multi-resolution approach based on the generalization of the cascade! algorithm. This method allows reconstruction of non-subsampled images that correspond to the decomposition previously done at a chosen scale. This new approach provides efficient tool for analyzing multi-scale information contained in range images. Thus, this approach may be applied on any 3D objects for extracting 3D features such as straight or smooth ridges, or object envelope. For example, we applied this method to the characterization of clam shells in order to reveal growth increment features.