Ki-Won Ahn

A prototype of digital photogrammetric algorithm for estimating roughness of rock surface

This study introduces the efficiency of using prototype digital photogrammetry for measuring the roughness of rock surfaces, employing digital stereo images obtained from a high resolution Kodak DCS 420 non-metric digital camera and a Rolleiflex 6006 metric film camera. To measure the surface roughness of test objects in the case of non-topographic applications, reference surfaces are mathematically estimated using the least squares method. The roughness processing capability of a digital camera and a metric film camera is evaluated using an arbitrarily chosen reference surface on the sample being studied. Then the results are compared with the measurements obtained using a laser profilometer. The RMS roughness and Z2s parameters estimated using the DCS 420 non-metric digital camera ranges from 0.001 mm to 0.067 mm and from 0.007 to 0.073, when compared to the laser profilometer values. In the case of the Rolleiflex 6006 metric film camera, the RMS and the Z2s parameters range from 0.010 mm to 0.056 mm and from 0.005 to 0.031. The prototype photogrammetric algorithm is consequently suitable for measuring rock surface roughness.

Analysis of the Influence of Greenbelts on Urban Growth in Korea Using the Remote Sensing Technique

The influence of the Korean greenbelt system on urban growth was verified through analysis of the land cover change using satellite images. We selected four case study areas out of a total of 14 greenbelt areas according to the scale of the city and the purpose of the greenbelt area. The case cities were a metropolis, a medium-sized or small city, a coastal industrial city and a coastal tourist city. We also selected comparative cities whose external conditions were similar to the case cities. The shape of each urban growth was compared by way of the analysis of land cover changes. Areas inside and outside the greenbelts were analyzed separately. The technique of remote sensing was effective for the macroscopic analysis and it seemed that each greenbelt was accomplishing its role as desired. As a result of the analysis of the relationship between urbanization and topographical factors, urbanization appeared to be affected by elevation rather than by slope and aspect did not appear to be significantly related to urbanization.