Defence Research Establishment Ottawa 

                                                                                                                                                       

                                               

   



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he A.U.G. Signals’ On-line Automatic Image Alignment tool is a new Web-based application for registering multi-sensor satellite images for image fusion operations. It is a distributed processing system intended to provide a service to Canadian Geospatial Data Infrastructure (CGDI) users through the GeoConnections Discovery Portal. In addition, this service will be provided directly to those that access the web pages of A.U.G. Signals Ltd. (www.augsignals.com or www.signalfusion.com) which will be linked to the GeoConnections Discovery Portal and CGDI.

This web image registration service is made available with the essential support of the GeoInnovations 2000 Program.

The A.U.G. Signals project rounded a team, including Defence Research Establishment Ottawa, University of Calgary and University of Guelph, that developed a consensus understanding of Internet based data processing, representing a break with current research carried out elsewhere.  The tremendous benefit of this cooperation is the evolvement of a robust core expertise for a future extensive Internet fusion centre that will increase the visibility of the CGDI in a global, event-driven market

                                                 

                 (a)                                              (b)                                            (c)                                                 (d)

RADARSAT original images and registered by A.U.G. Signals automatic algorithm images: (a) original image of C0006846 taken on Aug. 08, 97 (b) original image of M0115293 taken on May 28, 97 (c) registered image of C0006846, (d) registered image of M0115293        

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he user will get instructions via a friendly graphic interface about how to download the registered images. A name will be assigned for the files with the aligned images and will be provided to the user. Due to the computational requirements, the registered images are expected to be downloaded at a later time, depending of the computers current load and the size and the parameters of the input images. The user is expected to check the ftp directory (ftp://www.signalfusion.com/output_images) to see if the files of interest have been placed. A version of this service, where the user will be automatically notified by email when the registered images are ready, is currently under development.

 

The innovative technology of A.U.G. Signals has all the advantages of current registration techniques, plus it can estimate reference (control) points automatically at high degree of accuracy and with zero false alarms.  Image registration is achieved using nine parameters (three for translation, three for rotation and three for scaling). Hence, the line of sight between the sensor and the field of view, the image’s rotations and the ground resolution are automatically corrected.


 


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he registration accuracy is inversely proportional to the number of control points that are being automatically found in the two images prior to registration.  The user may be able to select the registration accuracy by setting the algorithm parameters (e.g. window size) to locate more or fewer control points. Sequential use of A.U.G. Signals registration on the same images results in a user defined registration accuracy.

 

It is recommended that the input images to be single band and not larger than 1000x1000 pixels due to the intense computation for finding the control points, and potential image nonstationarity to the registration parameters.
            

At present, SAR or Electro-optical data of the same or different wavelength (IR/IR, Visible/IR, Visible/Visible, SAR/SAR) are automatically registered. An upgraded version of A.U.G. Signals’ service will enhance the capabilities of the registration algorithm for the automatic alignment of EO with SAR images.