A 3D forest monitoring system,called FORSAT(a satellite very high resolution image processing platform for forest assessment),was developed for the extraction of 3D geometric forest information from very high resoluti...A 3D forest monitoring system,called FORSAT(a satellite very high resolution image processing platform for forest assessment),was developed for the extraction of 3D geometric forest information from very high resolution(VHR)satellite imagery and the automatic 3D change detection.FORSAT is composed of two complementary tasks:(1)the geometric and radiometric processing of satellite optical imagery and digital surface model(DSM)reconstruction by using a precise and robust image matching approach specially designed for VHR satellite imagery,(2)3D surface comparison for change detection.It allows the users to import DSMs,align them using an advanced 3D surface matching approach and calculate the 3D differences and volume changes(together with precision values)between epochs.FORSAT is a single source and flexible forest information solution,allowing expert and non-expert remote sensing users to monitor forests in three and four(time)dimensions.The geometric resolution and thematic content of VHR optical imagery are sufficient for many forest information needs such as deforestation,clear-cut and fire severity mapping.The capacity and benefits of FORSAT,as a forest information system contributing to the sustainable forest management,have been tested and validated in case studies located in Austria,Switzerland and Spain.展开更多
An innovative and practical satellite image product is described that is ideal for applications in Northern Canada because of its wide area coverage and mappingquality features.This product is generated from a new pro...An innovative and practical satellite image product is described that is ideal for applications in Northern Canada because of its wide area coverage and mappingquality features.This product is generated from a new procedure developed at the Canada Centre for Remote Sensing(CCRS)for processing Landsat 7 imagery,and by extension,imagery from other Earth Observation satellites.By working with multiple satellite passes,each containing the equivalent of multiple scenes,the new procedure could dramatically reduce the turn-around time for generating georeferenced image products,and also increase their geometric and radiometric accuracy compared to those produced by the current methods.The objective of the process has been to generate satellite image mosaics covering large areas(e.g.>500000 km^(2))with uniformly distributed errors at sub-pixel resolution.The paper discusses the theoretical basis of a photogrammetric adjustment for satellite imagery and the results obtained from several tests.The process is generic,involving a sensor model,a satellite orbit model and ground control information;thus it may be easily adapted to any satellite that allows for repeat coverage with overlapping paths.By performing an adjustment to correct the satellite position and attitude data prior to the production of orthoimage products,it is possible to create a mosaic with a single resampling process which minimises both the radiometric and geometric resampling artifacts.The results from three separate tests are presented,along with a discussion of the procedures that were followed in each case.All three tests have successfully demonstrated that sub-pixel sample size errors may be consistently obtained over large areas.A by-product process developed to support the measurement of ground control point coordinates for the satellite adjustment was the automatic matching of geographic features such as lakes and islands in vector data format.This has been a significant development in that it has eliminated manual intervention in the measurement展开更多
基金the EUROSTARS[grant number E!7358]funding scheme,co-funded by the European Commission and the participating countries.
文摘A 3D forest monitoring system,called FORSAT(a satellite very high resolution image processing platform for forest assessment),was developed for the extraction of 3D geometric forest information from very high resolution(VHR)satellite imagery and the automatic 3D change detection.FORSAT is composed of two complementary tasks:(1)the geometric and radiometric processing of satellite optical imagery and digital surface model(DSM)reconstruction by using a precise and robust image matching approach specially designed for VHR satellite imagery,(2)3D surface comparison for change detection.It allows the users to import DSMs,align them using an advanced 3D surface matching approach and calculate the 3D differences and volume changes(together with precision values)between epochs.FORSAT is a single source and flexible forest information solution,allowing expert and non-expert remote sensing users to monitor forests in three and four(time)dimensions.The geometric resolution and thematic content of VHR optical imagery are sufficient for many forest information needs such as deforestation,clear-cut and fire severity mapping.The capacity and benefits of FORSAT,as a forest information system contributing to the sustainable forest management,have been tested and validated in case studies located in Austria,Switzerland and Spain.
文摘An innovative and practical satellite image product is described that is ideal for applications in Northern Canada because of its wide area coverage and mappingquality features.This product is generated from a new procedure developed at the Canada Centre for Remote Sensing(CCRS)for processing Landsat 7 imagery,and by extension,imagery from other Earth Observation satellites.By working with multiple satellite passes,each containing the equivalent of multiple scenes,the new procedure could dramatically reduce the turn-around time for generating georeferenced image products,and also increase their geometric and radiometric accuracy compared to those produced by the current methods.The objective of the process has been to generate satellite image mosaics covering large areas(e.g.>500000 km^(2))with uniformly distributed errors at sub-pixel resolution.The paper discusses the theoretical basis of a photogrammetric adjustment for satellite imagery and the results obtained from several tests.The process is generic,involving a sensor model,a satellite orbit model and ground control information;thus it may be easily adapted to any satellite that allows for repeat coverage with overlapping paths.By performing an adjustment to correct the satellite position and attitude data prior to the production of orthoimage products,it is possible to create a mosaic with a single resampling process which minimises both the radiometric and geometric resampling artifacts.The results from three separate tests are presented,along with a discussion of the procedures that were followed in each case.All three tests have successfully demonstrated that sub-pixel sample size errors may be consistently obtained over large areas.A by-product process developed to support the measurement of ground control point coordinates for the satellite adjustment was the automatic matching of geographic features such as lakes and islands in vector data format.This has been a significant development in that it has eliminated manual intervention in the measurement
