PV-WAVE® Helps VEXCEL and Jet Propulsion Laboratory Develop Ice-tracking System

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  • Resource preservation
  • Overlaid maps
Peering at the images displayed on the computer screen, one gets the feeling that scientists who track ice flows for a living must have a love affair with jigsaw puzzles. Jagged hunks of ice of all sizes cram the image in chaotic array.

But trained researchers can now analyze and process these images through an automated system developed for the Jet Propulsion Laboratory (JPL), located in southern California, by VEXCEL Corp. The VEXCEL system uses Visual Numerics' PV-WAVE to produce motion grids, the primary objective of ice-motion analysis. The research is of interest because of the wide geographic extent of sea ice and its impact on climate, offshore drilling and shipping.

Called the Geophysical Processor System (GPS), the program is being developed jointly by VEXCEL and JPL for the Alaska SAR (Synthetic Aperture Radar) Facility. The operation, based at the University of Alaska in Fairbanks, is funded by NASA and began receiving data when the European space Agency's European Remote Sensing (ERS) satellite was launched in 1991. The European agency also uses PV-WAVE in all phases of the ERS-1 satellite program, including satellite commissioning and analysis of ground station data.

The SAR facility consists of the receiving ground station, the SAR Processor System, the Archive and Operations Subsystem, which converts and stores all SAR data in a JPL standard, and the Geophysical Processor System developed by VEXCEL.

At present, the GPS routinely examines space-borne radar images taken days apart to produce high-resolution maps of ice motion and ice classification in the Arctic Ocean. Each data field consists of images 100 by 100 kilometers with a spatial resolution of approximately 100 meters.

Visual Numerics' visual data analysis (VDA) product, PV-WAVE, assists researchers who will be using the one-of-a-kind Alaska SAR system. The GPS operator will use PV-WAVE as a quality assurance and control tool to assure smooth operation of the automated image processing. The program assists in the development and production of end-user products and is unique because it is an automated production setup rather than a pure research tool.

PV-WAVE's functions include

  • Checking for proper algorithmic function by displaying feature boundaries around objects found in threshold images.
  • Generating color-coded maps to compare environmental conditions such as the age of the ice being studied. Quality assurance indications for the ice classification algorithm are input by PV-WAVE.
  • Viewing the results of the wave spectral algorithm to assure proper functionality.

VEXCEL's operation and its use of PV-WAVE give researchers end-user products that until now were generated manually. Researchers no longer need to visually compare two images and mark changes with a grease pencil. Instead, they request motion or classification data and images from the Archival and Operations System (AOS) that have already been automatically processed. The system achieves this by checking new images with stored images. Once GPS determines that a match is made, it requests those images that it does not have on line. Upon receiving these images, it performs the processing and returns the product back to the AOS for archiving and retrieval by connected users.