Document Type : Research Paper
Author
Scientific Board, Soil Conservation and Watershed Management Research Institute, Iran
Abstract
Remotely sensed data is now being acquired and it is hoped the earth’s surface will be imaged more and more precisely to support their information systems by accurate data with high spatial resolution. The most advantage of this technique can be mentioned to acquire earth surface data with all of its details depend on the spatial resolution of satellite imagery. Due to remote sensing applications, there are some factors with efficient effects on the accuracy of the obtained results. Such that, there is not avoidable Relief Displacement correction in DEM generation or data fusion works. A lot of researches have been done to remove Relief Displacement caused by imaged feature’s height and scanning array by different algorithms of Ortho Photo rectification. In this approach the geometry of 1A and 1B level products of ASTER images was studied to develop a method based on rotation re sampling for Epipolar Stereo Pair Model generation in Non-Photogrametric software. Then the generated model was used to digitize contour lines with 100 meters interval of constant parallax (in row-parallax on the screen, i.e. col= 0). The result of comparison shows a consistent shift in georeference of digitized contour map with respect to the existing contour map and ground control points that can be caused by the effect of side ward looking angle and height of feature. Thus, the effective parameters such as pointing angle and height of feature were applied to develop a mathematical formula in Excel software to measure amount of shifts and finally correct it. The research show the amounts of shift are varying depends on position of the points in the image and its heights. Furthermore, the developed formula enables us to remove Relief Displacement without any changes on the radiometric properties of image data.
Keywords
)