• Proceedings of the KSRS Conference
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• v.1
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• pp.508-511
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• 2006

Generally, stereo pair images are necessary for 3D viewing. In the absence of quality stereo-pair images, it is possible to synthesize a stereo-mate suitable for 3D viewing with a single image and a depth-map. In remote sensing, DEM is usually used as a depth-map. In this paper, LiDAR data was used instead of DEM to make a stereo pair from a single aerial photo. Each LiDAR point was assigned a brightness value from the original single image by registration of the image and LiDAR data. And then, imaginary exposure station and image plane were assumed. Finally, LiDAR points with already-assigned brightness values were back-projected to the imaginary plane for synthesis of a stereo-mate. The imaginary exposure station and image plane were determined to have only a horizontal shift from the original image's exposure station and plane. As a result, the stereo-mate synthesized in this paper fulfilled epipolar geometry and yielded easily-perceivable 3D viewing effect together with the original image. The 3D viewing effect was tested with anaglyph at the end.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.187-190
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• 2007

This study is for analyzing best band in image matching using correlation coefficient of left and right images of stereo image pair, lot red, green, blue band images separated from color aerial photo and gray image converted from the same color aerial photo image. The image matching is applied to construct Digital Elevation Model(DEM) or terrain data. The correlation coefficients and variation by change of pixel patch size are computed from pixel patches of which sizes are $11{\times}11{\sim}101{\times}101$. Consequently, the correlation coefficient in red band image is highest. The lowest is in blue band. Therefore, to construct terrain data using image matching, the red band image is preferable. As the size of pixel patch is growing, the correlation coefficient is increasing. But increasing rate declines from $51{\times}51$ image patch size and above. It is proved that the smaller pixel patch size than $51{\times}51$ is applied to construct terrain data using image matching.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.1
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• pp.13-19
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• 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 KIEE Conference
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• 2005.07d
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• pp.2921-2923
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• 2005

This paper presents to generate 3D building model using estimation of rooftop surface after 3D line segment extraction using hybrid stereo matching techniques in terms of the co-operation of area-based stereo and feature-based stereo. we first performed a junction extraction from 3D line segment data which was obtained by stereo images, and finally generated building's reliable rooftop surface model using LSE(Least Square Error) method after creating surfaces by grouped and fixed junction points. we generated synthetic images for experimentation by photo-realistic simulation on Avenches data set of Ascona aerial images.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.4
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• pp.77-87
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• 2004

It is important for hydrographers to extract the accurate cross section of a river for the hydrographical analysis of the topography. Aerial photographs were used to extract the cross section of a river for the advantages of the accuracy and economical efficiency in this study, while the direct measurement has been used in existing studies. An ortho-rectified photo map using imageries taken by the PKNU 2 (High-resolution, multi-spectral, aerial photographic system developed by our laboratory) was generated using the surveyed data and a digital map. The cross section of a river that was obtained from the ortho-rectified by the surveyed Kinematic data of GPS was compared with the result using ImageStation stereo-plotter of corp. Z/I Imaging. As a result of this study, the RMSE in the ortho-rect process using the surveyed GPS data was lowered as from 5.5788 pixels (about 2m) to 2.84 (about 1m) in comparison with it in the process using a digital map. The surveyed kinematic GPS in extraction of the cross section of a river was excellent as 6.6cm of the planimetric and precision in the confidence level of 95%. The correlation coefficient between the result from the using stereo-plotter and the extraction of cross section of a river using aerial photos was 0.8 hydrographical acquisition of it using PKNU 2 imagery will be possible.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.687-695
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• 2011

Many internet portals provide maps with spatial information services. Recently, various images including aerial, satellite, street view, and photo-realistic 3D city models are provided as well as maps. This study suggested a method for geometric correction of the panoramic aerial images in the internet portal and 3D building modeling using information which is available in the internet. The key of this study is to obtain all necessary data easily from internet without restrictions. Practically, the ground control coordinates could be available from geo-referenced internet maps, and stereo pairs of the aerial images and close-range photographs for photo-realistic object modeling are provided by the internet service. However, the ground control points are not suitable for accurate mapping. RMSE of the plotting was about 9 meters and reduced upto 4 meters after coordinate transformation. The proposed methods would be applicable to various applications of photo-realistic object modeling which do not require high accuracy.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.217-222
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• 2006

In this study, we performed three dimensional(3-D) modeling and simulation of terrain surfaces by using large scale aerial photographs. The objectives of this study are to use landscape analysis including 3-D database of built environments. The test area is selected around Olympic stadium located in Susung-gu, Daegu. A 1:5,000 scale of ortho-photo map is generated by photogrammetric procedures from 1:20,000 scale of aerial photographs, Digital Elevation Model (DEM) is also extracted from stereo aerial photographs or digital maps. The heights of buildings are determined using GPS control survey and aerial photographs in the test area, DEMs are extracted from the digital map. And then the two are combined three-dimensional changes of landscape views of buildings with terrain are simulated.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.4
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• pp.277-285
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• 2004

We present a new hybrid stereo matching technique in terms of the co-operation of area-based stereo and feature-based stereo. The core of our technique is that feature matching is carried out by the reference of the disparity evaluated by area-based stereo. Since the reference of the disparity can significantly reduce the number of feature matching combinations, feature matching error can be drastically minimized. One requirement of the disparity to be referenced is that it should be reliable to be used in feature matching. To measure the reliability of the disparity, in this paper, we employ the self-consistency of the disunity Our suggested technique is applied to the detection of 3D line segments by 2D line matching using our hybrid stereo matching, which can be efficiently utilized in the generation of the rooftop model from urban imagery. We carry out the experiments on our hybrid stereo matching scheme. We generate synthetic images by photo-realistic simulation on Avenches data set of Ascona aerial images. Experimental results indicate that the extracted 3D line segments have an average error of 0.5m and verify our proposed scheme. In order to apply our method to the generation of 3D model in urban imagery, we carry out Preliminary experiments for rooftop generation. Since occlusions are occurred around the outlines of buildings, we experimentally suggested multi-image hybrid stereo system, based on the fusion of 3D line segments. In terms of the simple domain-specific 3D grouping scheme, we notice that an accurate 3D rooftop model can be generated. In this context, we expect that an extended 3D grouping scheme using our hybrid technique can be efficiently applied to the construction of 3D models with more general types of building rooftops.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.04a
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• pp.321-326
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• 2003

The subjects of this study are to examine and to apply the methods of making 1:5,000 scale maps using 1m resolution stereo images of IKONOS for the Munsan area of Paju-city where aerial photo surveying cannot possible because of security conditions. GCP(Ground Control Point) were acquired from GPS surveying and were to perform geometric corrections on images. Digital Map used IKONOS stereo images and it worked from the digital analytical stereoplotter. From field investigation, RMSE errors of the plane and vertical positions are estimated to 1.706m and 1.231m, respectively. The plane accuracy is better than an accuracy required by NGIS (national GIS) programs. Local information from field investigation was added and the resulting maps should be good as digital map under the scale of 1/5,000.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.04a
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• pp.471-477
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• 2003

This paper presents an algorithm that automatically extracts buildings among many different features on the earth surface by fusing LIDAR data with panchromatic aerial images. The proposed algorithm consists of three stages such as point level process, polygon level process, parameter space level process. At the first stage, we eliminate gross errors and apply a local maxima filter to detect building candidate points from the raw laser scanning data. After then, a grouping procedure is performed for segmenting raw LIDAR data and the segmented LIDAR data is polygonized by the encasing polygon algorithm developed in the research. At the second stage, we eliminate non-building polygons using several constraints such as area and circularity. At the last stage, all the polygons generated at the second stage are projected onto the aerial stereo images through collinearity condition equations. Finally, we fuse the projected encasing polygons with edges detected by image processing for refining the building segments. The experimental results showed that the RMSEs of building corners in X, Y and Z were ${\pm}$8.1cm, ${\pm}$24.7cm, ${\pm}$35.9cm, respectively.