suter@latcs1.oz.au (David Suter) (04/04/91)
Technical Reports Available Constraint Networks in Vision / Mixed Finite Elements The author has investigated methods of using (Augmented) Lagrangian approaches in various ways and in various problems in computer vision. These Augmented Lagrangian approaches generalise many of the (Penalty) based approaches used in most approaches. The major advances reulting from this approach are 1) The method can be used to reformulate visual reconstruction problems in a manner that uses mixed finite elements and thus allows the use of many computational schmes similar to those used in fluid mechanics. The mixed finite elements are simpler than those finite elements used previously. 2) The method lends itself to analog network solutions in a straightforward way by employing the approach of Platt. 3) The realization of these analog networks in terms of transconductance amplifiers (ala Mead) is simple - the networks produced by this method are far simpler than those proposed by others (Harris). Thus the work extends from problem reformulation right down to practical implementation using either more standard digital techniques (mixed finite element) or more exciting new analog networks (right down to the transistor level). Some aspects of the work are to shortly appear at IJCNN-91 (Seattle July) but more information can be obtained by requesting some or all of the following technichal reports: 1. D. Suter "Mixed Finite Element Formulation of Problems in Visual Reconstruction" La Trobe University Technical Report No. 2/90, Jan. 1990 This outlines the basic reformulation in Augmented Lagrangian terms and shows how this generalizes approaches such as Horns recent shape from shading approach. It also forshaddows the developments from here to analog networks that generalize that of Harris. 2. D. Suter "Visual Reconstruction and Edge Detection Using Coupled Deriviatives" La Trobe University Technical Report No. 7/90, June 1990 This contains examples obtained using Platts constraint networks. 3. D. Mansor and D. Suter "An Analogue Circuit for First Order Regularization" La Trobe University Technical Report No. 2/91, March 1991 This shows how to realize the networks using transconductance amps and how to simulate using SPICE (3b1). Copies of these reports can be obtained by email or by writing to the author: --------------------- David Suter ISD: +61 3 479-2393 Department of Computer Science and Computer Engineering, STD: (03) 479-2393 La Trobe University, ACSnet: suter@latcs1.oz Bundoora, CSnet: suter@latcs1.oz Victoria, 3083, ARPA: suter%latcs1.oz@uunet.uu.net Australia UUCP: ...!uunet!munnari!latcs1.oz!suter TELEX: AA33143 FAX: 03 4785814