• Spatial Information Research
• /
• v.19 no.1
• /
• pp.51-59
• /
• 2011

We produced true ortho images after interpolating occlusion areas and relief displacement of building as well as producing ortho-images to use backward image of ADS which is a aerial digital camera of line type. Also, I was able to produce high quality ortho-images using a small mount of Ground Control Points(GCP) relatively to compare to frame type camera from the evaluation of horizontal position accuracy using ground check points, photo control points for the verification of ortho-images and true-ortho images. Also, I was able to verify the effectiveness in interpolating occlusion areas cause the length overlap was 100% when producing true-ortho images of line type camera.

• Korean Journal of Remote Sensing
• /
• v.26 no.3
• /
• pp.347-359
• /
• 2010

Ortho-photos provide valuable spatial and spectral information for various Geographic Information System (GIS) and mapping applications. The absence of relief displacement and the uniform scale in ortho-photos enable interested users to measure distances, compute areas, derive geographic locations, and quantify changes. Differential rectification has traditionally been used for ortho-photo generation. However, differential rectification produces serious problems (in the form of ghost images) when dealing with large scale imagery over urban areas. To avoid these artifacts, true ortho-photo generation techniques have been devised to remove ghost images through visibility analysis and occlusion detection. So far, the Z-buffer method has been one of the most popular methods for true ortho-photo generation. However, it is quite sensitive to the relationship between the cell size of the Digital Surface Model (DSM) and the Ground Sampling Distance (GSD) of the imaging sensor. Another critical issue of true ortho-photo generation using high resolution satellite imagery is the scan line search. In other words, the perspective center corresponding to each ground point should be identified since we are dealing with a line camera. This paper introduces alternative methodology for true ortho-photo generation that circumvents the drawbacks of the Z-buffer technique and the existing scan line search methods. The experiments using real data are carried out while comparing the performance of the proposed and the existing methods through qualitative and quantitative evaluations and computational efficiency. The experimental analysis proved that the proposed method provided the best success ratio of the occlusion detection and had reasonable processing time compared to all other true ortho-photo generation methods tested in this paper.

• Journal of Korean Society for Geospatial Information Science
• /
• v.6 no.2 s.12
• /
• pp.45-58
• /
• 1998

Digital photogrammetry is growing today using inexpensive personal confuter and digital image Processing technique instead of expensive analytical plotter in data acquisition from aerial photograph. Ortho photo in replacement of paper map is indispensable in the application of Geo-Spatial Information System and research activities about it are active in the domestic domain. Also the availability of ortho photo is greatly various in existing related fields using topographic map and expected to be used for new technology in near future. For this purpose, design of each module for ortho photo has been carried out with digital map and image. It was shown that the batch program for ortho photo generation developed in this study, could be used effectively as an effective data acquisition method for GSIS.

• Korean Journal of Geomatics
• /
• v.3 no.1
• /
• pp.1-6
• /
• 2003

The purpose of this study is to make out a history of the coastline deformation with annual aerial photos of the target area and to suggest an efficient method for interpreting the coastline deformation. First, there were difficulties in obtaining annual aerial photos of an identical area as well as collecting periodical datum because of too much change of the real area during more than 27 years. Besides the past aerial photo is inferior to the latest one in quality. So there is nothing but to exclude an accuracy evaluation of the ortho photo. Taken into account the extent of the coastline change for 27 years is more than 10M and the all errors of the ortho image is included in this extent, both an accuracy and an error are ignored. The result of this study show that the coastline in the sea area of Namhangjin maintain advanced forward the ocean and keeps on moving with maintaining fairly wider shape of balance beach. Also The coastline deformation off l㎞ from the estuary is greatly irregular, which means the erosion of the sea in this area is in progress. The latest data being the aerial photo in 1996, it is difficult to find out the current conditions of a coastal erosion. However, considered the construction of a breakwater in Anmok Harbor is going on, the beach erosion becomes more accelerative recently. The aerial photos of the present Namhangjin's situation will make it possible to understand the history of the coastline change more accurately.

• Journal of Korean Society for Geospatial Information Science
• /
• v.22 no.4
• /
• pp.159-164
• /
• 2014

These days, inexpensive and high efficiency UAV of disaster prevention and spatial information has been given more attention. But studies about test of accuracy of UAV were not enough despite high interest. This research produced DSM and ortho photo and estimated accuracy by comparing coordinates with GNSS survey to evaluate outcome of fixed wing UAV. The ortho photo was found to make use of it to update 1/1,000 map. This research investigated spatial information construction using existing terrestrial LiDAR to suggest effectiveness of fixed wing UAV.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.26 no.6
• /
• pp.633-641
• /
• 2008

This study introduces the method of detecting and restoring occlusion areas by using epipolar algorithm and K-means classification algorithm for true ortho-photo generation. In the past, the techniques of detecting occlusion areas are using the reference images or information of buildings. But, in this study the occlusion areas can be automatically detected by using DTM data and exterior orientation parameters. The detected occlusion areas can be restored by using anther images or the computed values which are determined in K-means classification algorithm. In addition, this method takes advantages of applying epipolar algorithm in order to find same location in overlapping areas among images.

• Proceedings of the Korean Society of Radiological Science
• /
• 1991.05a
• /
• pp.21.1-21.1
• /
• 1991

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.20 no.1
• /
• pp.13-19
• /
• 2002

In a different way of satellite image or aerial photo, the image acquired by terrestrial photogrammetry has to go through complicated management according to the desired precision and analysis range. In this study, digital surface model and ortho image for cultural asset, terrestrial structures, were made by reflectorless total station in order to increase the application of single photo, and that was analyzed and compared with the method using stereo image. Single photo is expected to be utilized as the measuring method for drawing cultural assets or examining the stability of slope in which high precision doesn't need by performing the various geometric and visual analysis using ortho image made by excluding the difficulties of acquisition and plotting of stereo image.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2004.04a
• /
• pp.541-546
• /
• 2004

This study compare the coordination and area between cadastral map digital data corrected by normal nap and serial cadastral map edited by formal data. By superposition ortho image made from aerial photo to serial cadastral map, we propose the method to improve the confidence and use the ortho image efficiently in cadastral part.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.19 no.2
• /
• pp.109-115
• /
• 2001

Recently, in accordance with the introduction of Digital Photogrammetry Systems the use of Digital ortho-photo images have increased and progressed in the study which extract the features from digital ortho-photo image semi-automatically or automatically. However, there are a limit. It has proved in many studies that recognition of the attribution or the features from panchromatic aerial photo is restricted. In this study, I compared color aerial images with panchromatic aerial images and analyzed the characteristics of color aerial images and feature entities which can be extracted semi-automatically. I analyzed extracted feature entities are compared with digital map at a scale of 1:5,000 have constructed in National Geography Institute. With this result, I analyzed the capability of feature extraction and proposed a plan for the study in the future.