الفهرس | Only 14 pages are availabe for public view |
Abstract The aeril photo is a linear perspective picture of a part of the earth’s surface.from geometrical point of view,the aerial photo contains error caused by tilt and relief displacements.Tilt and relief errors can be eliminated by dfferentail rectification process where small elements of the stereoscopic model is scanned in a differential rectifier for producing an orthophoto. The produced orthophoto contains all the natural and artificial features in their correct orthogonal projection. The orthophoto is a combination of the advantages of both the conventional map and aerial photo. Therefoe,an orthophoto map can be used as a complete substitute of the conventional map in some regions. Stereoscopic measurements can be achieved by introducing mechanical parallaxes to the orthophoto. This orthophoto is called the sterteomate. If a series of orthophotos are pieeced together in the from of orthomosaic,the scaling accuracy will be very high limited only by the approximation mads in the differential rectification technique. Several techniqes can be used for producing orthophotos. These techniques depends on the projection of the image from the diapositive to the orthonegative. |