| Summary: | 碩士 === 中正理工學院 === 軍事工程研究所 === 87 === Since the development of photogrammetry at the beginning of the nineteenth century, photograph rectification has been regarded as one of the most important aspects of photogrammetry. Nevertheless, due to limits of facilities and techniques, photograph rectification at that time could only eliminate the tilt displacement caused by tilted photo axis and correct photograph scale, but couldn’t eliminate relief displacement. The application of photograph rectification was suitable only for flat areas and not for mountainous terrain. In 1955, the ortho-rectifier was invented; hence the displacement caused by earth relief could be removed. This ortho-rectifier adopted differential rectification, divided the photograph into numerous small pieces, took each piece as one unit, and rectified each unit according to its correlative earth elevation.
Recently, with the swift development of computer techniques, photogrammetry has improved greatly. Furthermore, with the appearance of Digital Image Workstation photograph rectification has become digitalized. By using a high geometric accuracy and high-resolution scanner, we can transform the analog photograph into a digital image, and then rectify it pixel by pixel. Using a DEM may be enough for flat areas, but in mountainous terrain, the insufficient data will result in a poor outcome.
This research provides a combined DEM method for producing digital ortho images in order to improve the accuracy and efficiency of digital ortho photo mapping procedures.
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