PhotoSat has made significant breakthroughs in producing digital elevation maps (DEM) from stereo satellite photos. These digital elevation maps (DEM) are used for land management, mining, construction, and land surveying in general. Seismic data processing has been used to make 3D maps of underground structures for many decades. Many of the ideas used to overcome technical challenges and to refine seismic processing have been used by PhotoSat to produce a production process for producing digital elevation maps (DEM) from stereo satellite images. For seismic processing, most of the effort in the development of the processing software goes into the automatic recognition and reduction of noise and processing artifacts. The same is true for PhotoSat's digital elevation maps (DEM) processor. Sources of the noise includes errata and deviations in the geometries of the ray paths from each pixel of the photo to the satellite camera. The origins of processing artifacts include areas of the terrain that have uniform optical echo and areas where steep gradients shield portions of the ground surface on at least one of the satellite photos. Using seismic processing as a conceptual model, the PhotoSat stereo satellite processor has been designed to manage large volumes of raw data. The current production processing software automatically produces digital elevation maps (DEM) which need very limited hands-on editing for rural areas with sparse vegetation. The advantage for using satellite images for producing digital elevation model (DEM) data is that the inherent time delays in gathering the data manually or by airplane flyovers is eliminated. You do not need teams of technicians and surveyors to transport and house. No permits are required. The satellites are already on the job for you. The satellite may need to be re-tasked, but that process is procedural and simple. As soon as the satellite photo data is collected, the PhotoSat processing takes place and the digital elevation model (DEM) data is produced. Think about the advantages of obtaining all the data you need in a few days instead of a few weeks or months. PhotoSat currently has a prototype application to automatically produce digital elevation maps (DEM) and bare earth surface models for areas with trees and buildings less then 30m tall. The results of this prototype process still includes some processing artifacts which requires hands-on editing after the automatic has processed the raw data. PhotoSat's goal for 2Q 2009 is to develop production processes to automatically attenuate these artifacts to produce digital elevation maps (DEM) and bare earth digital terrain models that requires very limited hands-on editing for treed and suburban areas.
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PhotoSat has made significant breakthroughs in producing digital elevation maps (DEM) from stereo satellite photos. These digital elevation maps (DEM) are used for land management, mining, construction, and land surveying in general. Seismic data processing has been used to make 3D maps of undergroun
Gerry Mitchell is a Professional Geoscientist and Geophysicist in Canada. As President of PhotoSat Information Ltd., he has led the creation of PhotoSat's new digital elevation model (DEM) production system.
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