Vector field restoration by the method of convex projections

COMPUTER

VISION,

GRAPHICS,

Abstracts

AND IMAGE

PROCESSING

52,306-307

of Papers Accepted

(1990)

for Pubkation

PAPERS Vector

Field

Restomtiotz

by the Method

of Convex

Ptqiections.

PATRICE

Y.

SIMARD

AND

Grjy

E.

Institut de Genie Biomedical Ecole Polytechnique, C. P. 6079, Succ A, Montreal, P.Q.. Canada H3C 3A7. Received October 25, 1988; accepted June 18, 1990.

MAILLOUX.

In this paper, the theory of image restoration by projections onto closed convex sets is applied to the restoration of vector fields. A set of useful projection operators is presented together with a linear time numerical implementation. These projection operators can be used to restore from partial information the velocity or deformation fields computed between successive views of a scene. They also find applications in the restoration of vector fields of physical quantities as those encountered in mechanics, hydrodynamics, or electromagnetism. The method is compared with the variational approach and illustrated by restoring simulated vector fields.

NOTES Object Recognition in Pictorial Zkta Management. WILLIAM I. GROSKY. Computer Science Department, Wayne State University, Detroit, Michigan 48202; RAJIV MEHROTRA. Computer Science and Engineering Department, University of South Florida, Tampa, Florida 33620. Received February 2, 1987; accepted June 18, 1990.

Index-Based

This paper emphasizes model-based representations of images by content, as well as new, efficient object recognition, which also permits the efficient insertion and deletion of object models, called data-driven indexed hypotheses: the insertion and deletion of object models, a performance/space trade-off which can be used to improve the recognition capabilities of our approach and a secondary memory implementation of our approach. We also report the results of a much more complete set of experiments for the data-driven indexed hypotheses.

Efiient

Pam&l

Implementat%on

of the Hough

Transform

on a Distributed

Memoq

M. SANDLER. Department of Electrical Engineering, United Kingdom. Received February 1.5, 1989; accepted June 18, 1990.

A.

NAQUI,

AND

System.

D. BEN-TZVI,

Ring’s College, London,

Normally, in parallel implementations of the Hough transform either the transform space or the set of image features can be distributed among the processing elements. A method is proposed to link parallel access to feature points in the image, and parallel access to the transform space. A synchronous processing sequence is suggested such that both can be distributed. Real-time performance has been obtained on a MIMD distributed memory architecture.

Reusoning in Object Exksction. AMNON MEISEL~ AND DORON MINTZ. DepartmentofMathematics and Computer Science, Ben-Gurion University of the Negev, Beer-Sheva, 84-105, Israel. Received September 28, 1988; accepted June 18, 1990.

Symbolic

A realization of the top-down use of knowledge in the process of extraction of simple man-made from aerial photographs is presented. The finding of objects is performed by a reasoning

objects

306

0734-189X/90

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Copyright 0 1990 by Academic Press, Inc. All rights of reproduction in any form reserved.