To the Graduate Council: I am submitting herewith a dissertation ...

Chapter 2: Related Work 10In the literature, a common distinction is found between fine and coarse registrationmethods [Campbell01], which are often used in a two-stage fashion. Coarse orpreliminary registration can be obtained by several techniques, including hardwaresolutions, such as rotating tables, which were used to scan small objects. But morecommonly, a set of matches is used for the alignment of the views. Thesecorrespondence points can be obtained interactively as in most commercial 3Dmodeling packages [RapidForm02]. Fully automatic 3D matching using exhaustiveconstrained search techniques were attempted [Chen99]. However, these methods arecomputationally expensive and sensitive to noise. Invariant features are morefrequently employed to reduce the search space, playing an important role in systemsthat aim for the automation of the reconstruction process. To achieve fine registration,by far the most widely used algorithm is the Iterative Closest Point (ICP) algorithmand its very numerous variants and extensions. This accurate method is commonlyused as a refinement step after an initial coarse registration was obtained.2.1.1 Registration with invariant featuresGiven a set of corresponding points between two 3D data sets, Horn [Horn87] deriveda closed from solution to the absolute orientation problem. Similar results were alsoobtained in [Faugeras86]. Automatically establishing the set of correspondences to beused in such algorithm is a common interest to both registration and object recognitiontasks. Several feature descriptors were used to represent free-form surfaces and pointsets. In the class of global descriptors spherical representations such as the SphericalAttribute Image (SAI), which mapped surface curvature values into a tessellatedsphere, were employed for 3D registration [Higuchi95][Hebert95]. Also to thiscategory belongs the work of Lucchese et al [Lucchese02] extending frequencydomainmethods to range data registration. Park and Subbarao [Park04] employed theinvariant Stable Tangent Plan (STP) for crude registration.