福爾摩沙衛星二號立體像對產生數值地形模型之精度研究
Other Title
ACCURACY EVALUATION OF DIGITAL TERRAIN MODEL GENERATED FROM FORMOSAT-2 STEREO IMAGERY
Date Issued
2006
Date
2006
Author(s)
陳世師
Abstract
Formosa-2 is a satellite which Taiwan has full authority for management. It can not only acquire panchromatic imagery with spatial resolution up to 2 meter but also has the capability of taking stereo pair on track. Taiwan government depends heavily on Formosa-2 imagery in nature resource management as well as the prevention, control and damage evaluation of natural disaster such as typhoon, earthquake and flood. Therefore, this research aims at utilizing Formosa-2 stereo pair to generate DTM for analysis and applications in different fields, especially in the field of geography. The objectives of this research are followed. Firstly, to built a substitution for rapid generation of DTM from Formosat-2 stereo pair before ROCSAT-2 Image Processing Terminal start to provide DTM generation funtion. Secondly, to investigate the influence of ground control points to accuracy of DTM. Thirdly, to examine accuracy of DTM while using non-redundant ground control points. Fourthly, to evaluate accuracies of DTM generation and discuss the discrepancies of different methods such as theoretical accuracy analysis, experimental single-unit or bi-unit numerical analysis, profile analysis, geo-spatial analysis and vision analysis.
In this research, a Formosat-2 stereo pair has been geometrically rectified by using 6 ground control points and DSM is then generated by image matching technology. The results indicate that RMSE is about 6.2m to 9.4m in panchromatic mode and 7.7m to 11.5m in multi-spectral mode respectively. RMSE is a traditional way to express accuracy of DTM which is easily understood but is subjective to gross errors. Although the gross errors can probably be removed by coordinating with reference sequential index, RMSE can not effectively present the relief accuracy, geospatial relationship and error location. Traditional statistical numerical analysis is used in this research, moreover, I also utilize methods of profile analysis, water network extraction in geospatial analysis and visualized error contour map to strengthen the deficiency of RMSE mentioned above.
Subjects
立體對
數值地形模型
數值表面模型
Stereo Pai
Digital Terrain Model
Digital Surface Mode
Type
thesis