The use of partial differential equations in image processing has become an active area of research in the last few years. In particular, active contours are being used for image segmentation, either explicitly as snakes, or implicitly through the level set approach. In this paper, we consider the use of the implicit active contour approach for segmenting scientific images of pollen grains obtained using a scanning electron microscope. Our goal is to better understand the pros and cons of these techniques and to compare them with the traditional approaches such as the Canny and SUSAN edge detectors. The preliminary results of our study show that the level set method is computationally expensive and requires the setting of several different parameters. However, it results in closed contours, which may be useful in separating objects from the background in an image.

Presents performance results for three distributed computing environments using the three simulated computational fluid dynamics applications in the NAS Parallel Benchmark suite. These environments are the Distributed Computing Facility (DCF) cluster, the LACE cluster, and an Intel iPSC/860 machine. The DCF is a prototypic cluster of loosely-coupled SGI R3000 machines connected by Ethernet. The LACE cluster is a tightly-coupled cluster of 92 IBM RS6000/560 machines connected by Ethernet as well as by either FDDI or an IBM Allnode switch. Results of several parallel algorithms for the three simulated applications are presented and analyzed, based on the interplay between the communication requirements of an algorithm and the characteristics of the communication network of a distributed system.>

Article Free Access Share on The NAS parallel benchmarks—summary and preliminary results Authors: D. H. Bailey Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CA Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CAView Profile , E. Barszcz Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CA Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CAView Profile , J. T. Barton Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CA Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CAView Profile , D. S. Browning Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CA Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CAView Profile , R. L. Carter Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CA Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CAView Profile , L. Dagum Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CA Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CAView Profile , R. A. Fatoohi Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CA Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CAView Profile , P. O. Frederickson Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CA Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CAView Profile , T. A. Lasinski Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CA Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CAView Profile , R. S. Schreiber Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CA Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CAView Profile , H. D. Simon Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CA Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CAView Profile , V. Venkatakrishnan Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CA Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CAView Profile , S. K. Weeratunga Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CA Numerical Aerodynamic Simulation (NAS) Systems Division, NASA Ames Research Center, Mail Stop T045-1, Moffett Field, CAView Profile Authors Info & Claims Supercomputing '91: Proceedings of the 1991 ACM/IEEE conference on SupercomputingAugust 1991 Pages 158–165https://doi.org/10.1145/125826.125925Published:01 August 1991Publication History 405citation1,162DownloadsMetricsTotal Citations405Total Downloads1,162Last 12 Months161Last 6 weeks25 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF