In Photogrammetry we are mainly focusing on :
a) satellite remote sensing of earthquake, volcano, flood, and landslide hazards.
b) close range Photogrammetry.
c) Architectural Photogrammetry.
d) object recognition and reconstruction - traditional photogrammetry
Satellite remote sensing of earthquake, volcano, flood, landslide and coastal inundation hazardsGround-based seismological measurements, are yielding the principal data for modeling lithospheric processes and for accurately estimating the distribution of potentially damaging strong ground motions which is critical for earthquake engineering applications. Moreover, integrated with interferometric synthetic aperture radar, these measurements provide spatially continuous observations of deformation with sub-centimeter accuracy. Seismic and in situ monitoring, geodetic measurements, high-resolution digital elevation models (e.g. from InSAR, Lidar and digital photogrammetry).
Architectural PhotogrammetryFor more than 100 years photogrammetry has been done by specialists who took pictures with special metric cameras. But these specialists and their cameras are rare, so the percentage of properly documented architectural heritage is still very small. Strong revolution is coming on documenting and preserve architectural heritage.
Close range Photogrammetry *(Terrestrial photogrammetry)
Terrestrial photogrammetry can be used to record buildings and topographic profiles from easily obtained ground-based imagery in great detail. Measurements can be extracted from photographs for as-built drawings or export to CAD packages. Orthorectified views can also be made for scaled orthophoto representations.
object recognition and reconstruction - traditional photogrammetryThe process of stereo-photogrammetric documentation is complex, but straight forward. First, selected locations on a facade are measured using a surveying instrument called GPS, it is then photographed with a metric (calibrated) camera so that each photo overlaps the other creating a three dimensional image. Documentation work can cease at this stage with the photographs and survey information stored to form a permanent archival record. Or, the photographs and survey data can be used to make accurate and detailed line drawings of the facade.
Three-dimensional object recognition and reconstruction (ORR) is a research area of major interest in computer vision and photogrammetry. Virtual cities, for example, is one of the exciting application fields of ORR which became very popular during the last decade. Natural and man-made objects of cities such as trees and buildings are complex structures and automatic recognition and reconstruction of these objects from digital aerial images but also other data sources is a big challenge.
By
Naga raju
Spatial data Executive,
gisservices@yahoo.comgisvoice@yahoo.com