Presentation on theme: "IMAGE Dense DSMs from Stereo Imagery Dr. Philippe Simard President SimActive Inc."— Presentation transcript:
IMAGE Dense DSMs from Stereo Imagery Dr. Philippe Simard President SimActive Inc.
About SimActive Founded in 2003, SimActive is the developer of Correlator3D™ software, a patented end-to-end photogrammetry solution SimActive has been selling Correlator3D™ to leading mapping firms and government organizations around the world Correlator3D™ is the fastest commercial software to perform DSM generation DSMDTMMosaic3D Features
Correlator3D™ Software DSM Generation EO Refinement Mosaic Creation DEM Editing Orthorectification DTM Extraction Microsoft Ultracam Applanix DSS DiMAC Intergraph Z/I DMC VM A3 Mosaic Editing PROCESSING MODULES IMAGERY ADS80 Scanned Films Aerial GeoEye ALOS Prism Cartosat-1 Worldview Quickbird Ikonos SPOT Satellite Feature Extraction
DSM Generation A Digital Surface Model (DSM) is a representation of ground topography Main Processing Steps: 1. Correlation 2. Triangulation Bottom-up approach What is it? DSM Example
TriangulationCorrelation Focal point Image 1Image 2 Epipolar Traditional approach: How does it work? DSM Generation
DSM What is it? A dense DSM has a grid post spacing approaching the ground sampling distance (GSD) of the input imagery Dense DSM Generation SimActive has just released its next generation DSM engine capable of producing dense DSMs Dense DSM
Challenges 1. Correlation 2. Sensitivity 3. Density Process more difficult Radiometry differences between images Camera calibration Exterior orientation More points leads to longer processing time For dense DEM generation
Bottom-Up Derive solution Feature-Based High density in some areas only CPU Few cores Comparison Traditional Top-Down Test solutions Grid-Based High density in all areas GPU Hundreds of cores SimActive
Focal point Image 1Image 2 Top-Down Idea: test solutions and check whether they solve the correlation problem
Grid-Based Grid-based DEM is dense everywhere No interpolation Correlation performed on all points in the grid Adjacent solutions assist each other
GPU Possible Solutions Processing Results P 11 P 21... P n1 P 12 P 22... P n2... P 1n... P 2n...P nn GPU Cores These solutions are processed by the GPU simultaneously When a match is found, the problem is solved 1 23 Many possible solutions are prepared to be tested 1 2 3
Results Resolution: 25 cm Accuracy: 5 cm Resolution: 15 cm Accuracy: 5 cm Dense DSM DSM
Benefits World’s fastest commercially available DSM engine Direct DSM result removing the need to convert from a point cloud More points in low texture areas DSM precision is consistent and homogeneous Dense DSM
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