The C3 model could be used to improve the design of electronic geospatial displays by suggesting when a display will be too cluttered for its intended audience.

No abstract

When resurveying a seafloor area of interest during change detection operations, an automated method to match found bottom objects with objects detected in a previous survey allows the surveyor to quickly sort new objects from old. The change detection system developed at the Naval Research Laboratory contains modules for automatic object detection, feature matching using shadow outlining, scene matching using control-point matching, and visualization capabilities. This system was developed for sidescan sonar surveys using instrumentation such as the high-frequency Marine Sonic Technology sidescan sonar. In this paper, the authors describe modifications to the sidescan-based system required to perform change detection using Synthetic Aperture Sonar (SAS) bottom imagery.

Abstract-This paper presents an Automated Change Detectionand Classification (ACDC) System, developed by the Naval Research Laboratory (NRL) and the Naval Oceanographic Office (NAVOCEANO), which aids analysts in performing change detection in real-time (RT) by co-registering new and historical imagery and using automated change detection algorithms that suggest imagery changes. In this paper, ACDC-RT components are described and results given from a recent change detection experiment. The Navy requires a real-time change detection and classification system. This paper presents the Automated Change Detection and Classification -Real-Time System (ACDC-RT) developed by the Naval Research Laboratory (NRL) and Naval Oceanographic Office (NAVOCEANO) to assist change detection analysts by co-registering new imagery with historical, over the same area, and using automated algorithms to suggest possible changes between the two imagery sets (i.e., new contacts on the seafloor). ACDC-RT integrates Computer-Aided Detection, Classification, Search, and Feature-matching functions previously developed by NRL. Figure 1 shows the two main ACDC-RT displays: a timebased waterfall display of SSI as it is being collected (top) and a geo-registered waterfall display of historical SSI over the same area (bottom). ACDC-RT algorithms detected a minelike contact in the RT SSI (inset box on top) and matched it with the same contact observed in the past (inset box on the bottom). Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. Index Terms-Acoustic

This paper was first presented at a Symposium on ' Advanced Moving-Map Displays ' held on the 3rd and 4th of August 1999 by the US Naval Research Laboratory Detachment at the NASA Stennis Space Centre, Mississippi, and is reproduced in modified form with the kind permission of the NRL Commanding Officer, Captain Douglas H. Rau USN.Wavelets and wavelet transforms can be used for vector-map data compression. The choice of wavelet, the level of decomposition, the method of thresholding, the height of the threshold, relative CPU times and file sizes, and reconstructed map appearance were investigated using the Wavelet Toolbox of MATLAB. Quantitative error measures were obtained. For two test vector-map data sets consisting of longitude and latitude points, compressions of 35 to 50 percent (1n5 : 1 to 2 : 1) were obtained with root-mean-square errors less than 0n003 to 0n01m longitude\latitude for wavelet packet decompositions using selected wavelets.