1. Digital Distance Geometry – Applications to Image Analysis Dr. P. P. Das [email_address] , [email_address] Interra Systems, Inc. www.interrasystems.com ICVGIP ’04. Science City. 18-Dec-04
56. Chamfering for computing Distance Transform o a b a Forward Scanning From Left to Right and Top to Bottom Backward Scanning From Right to Left and Bottom to Top b Distance at o = min (Distance value at Neighboring pixel + local distance between them) 1. Initialize all distance values to a Maximum Value. 2. At every point o compute the distance value from its visited neighbors as follows: Extend this concept with larger neighborhood and dimension. o a b a b
72. Computation of minimal set of maximal disks 1. Compute Local Maximum Blocks from the distance transformed image. Form a relational table expressing the relationships between boundary pixels and individual disks. The problem is mapped to the covering of the list of boundary pixels with the optimal set of maximal blocks. 2 . 3. Nilson-Danielsson’96
76. Thinning from Distance Transform Compute the set of Maximal Blocks. Use them as anchor points while iteratively deleting boundary points preserving the topology. Vincent ’91, Ragnemalm ’93, Svensson-Borgefors-Nystrom ’99
83. Decomposition of 3D Objects Identification of seed of a component from inner layers of Distance Transformed Image. Seed-fusion by expansion and shrinking Region growing by reversed DT. Surface smoothing and merging. Svensson-Saniti di Baja’02
90. O(1) neighbors O(2) neighbors O(3) neighbors O(1) neighbors O(2) neighbors 2D 3D M-neighbors o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o