• Journal of Korean Society for Geospatial Information Science
• /
• v.3 no.2 s.6
• /
• pp.159-172
• /
• 1995

This study aims to apply digital photogrammetric methods on the close range photogrammetry. To get a three dimensional position with digital photogrammetric method, scanning, image matching, and bundle adjustment are performed. Comparing the three dimensional position computed by digital photogrammetric methods with ground survey values, the errors can be detected. Analyzing the errors, it is possible to present a new digital photogrammetric method for the close range photogrammetry. Image matching method used in this study is area-based pixel unit and subpixel unit method. As a result of the study, three dimensional position error is 3.32mm and the error in the single coordinate axis direction is 0.76mm in pixel unit and in subpixel unit, respective error is 3.98mm and 0.73mm.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.2
• /
• pp.827-833
• /
• 2012

In this paper, we propose an improved optical flow algorithm which reduces computational complexity as well as noise level. This algorithm reduces computational time by applying level simplification technique and removes noise by using eigenvectors of objects. Optical flow is one of the accurate algorithms used to generate depth information from two image frames using the vectors which track the motions of pixels. This technique, however, has disadvantage of taking very long computational time because of the pixel-based calculation and can cause some noise problems. The level simplifying technique is applied to reduce the computational time, and the noise is removed by applying optical flow only to the area of having eigenvector, then using the edge image to generate the depth information of background area. Three-dimensional images were created from two-dimensional images using the proposed method which generates the depth information first and then converts into three-dimensional image using the depth information and DIBR(Depth Image Based Rendering) technique. The error rate was obtained using the SSIM(Structural SIMilarity index).

• Korean Journal of Optics and Photonics
• /
• v.20 no.1
• /
• pp.16-22
• /
• 2009

We propose a method to convert a two-dimensional movie to a three-dimensional movie using normalized cut and optical flow. In this paper, we segment an image of a two-dimensional movie to objects first, and then estimate the depth of each object. Normalized cut is one of the image segmentation algorithms. For improving speed and accuracy of normalized cut, we used a watershed algorithm and a weight function using optical flow. We estimate the depth of objects which are segmented by improved normalized cut using optical flow. Ordinal depth is estimated by the change of the segmented object label in an occluded region which is the difference of absolute values of optical flow. For compensating ordinal depth, we generate the relational depth which is the absolute value of optical flow as motion parallax. A final depth map is determined by multiplying ordinal depth by relational depth, then dividing by average optical flow. In this research, we propose the two-dimensional/three-dimensional movie conversion method which is applicable to all three-dimensional display devices and all two-dimensional movie formats. We present experimental results using sample two-dimensional movies.

• Korean Journal of Geomatics
• /
• v.2 no.2
• /
• pp.131-137
• /
• 2002

The digital photogrammetric products have been increasingly used as an accurate foundation for representing information associated with infrastructure management. The technological advances in merging raster and vector data within the framework of GIS have allowed for the inclusion of DTMs and digital orthophotos with vector data and its associated attributes. This study addresses not only generating DEMs and digital orthophotos but producing three dimensional building models from aerial photos of an urban area by employing the digital photogrammetric technology. DEMs and digital orthophotos were automatically generated through the process of orientations, image matching and so on, and then the practical problems, which must be solved especially in applying to urban areas, were considered. The accuracy of produced digital orthophotos was derived by using check points. Also three dimensional visualization imagery, which is useful in the landform analysis, and 3D building models were produced. Digital photogrammetric products would be used widely not only as GIS framework data layers by using the GIS link function which links attribute and image information in the database for applying to infrastructure management and but as geospatial data for especially 3D GIS in urban areas.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.10B
• /
• pp.1111-1116
• /
• 2009

In this paper, we discuss distortion-tolerant pattern recognition using computational integral imaging reconstruction. Three-dimensional object information is captured by the integral imaging pick-up process. The captured information is numerically reconstructed at arbitrary depth-levels by averaging the corresponding pixels. We apply Fisher linear discriminant analysis combined with principal component analysis to computationally reconstructed images for the distortion-tolerant recognition. Fisher linear discriminant analysis maximizes the discrimination capability between classes and principal component analysis reduces the dimensionality with the minimum mean squared errors between the original and the restored images. The presented methods provide the promising results for the classification of out-of-plane rotated objects.

• Proceedings of the KSRS Conference
• /
• 2002.10a
• /
• pp.517-517
• /
• 2002

Recently in the field of telecommunication, there is much interest in geo-surface characteristics of urban areas. Geophysical properties of urban features are now incorporated with accurate positional information to model the telecommunication environment. In this study, three-dimensional buildings are geometrically reconstructed from existing vector maps and aerial images. Accurate digital vector maps are easily available in Korea. However existing maps, which had been produced for GIS applications, do not have height information which is critical to three dimensional building reconstruction. Image matching techniques were applied to aerial image stereopairs to automatically extract the height information of buildings. Planimetric coordinates from vector maps were used as initial guides in the process. Future studies will be undertaken to link geophysical properties to the three-dimensional spatial objects reconstructed from this study thus bringing the telecommunication environment model closer to reality.

• Journal of the Korea Society of Computer and Information
• /
• v.19 no.11
• /
• pp.53-61
• /
• 2014

In this paper, we propose a method using an image received by the depth camera in order to separate the wall in a three-dimensional space indoor environment. Results of the paper may be used to provide valuable information on the three-dimensional space. For example, they may be used to recognize the indoor space, to detect adjacent objects, or to project a projector on the wall. The proposed method first detects a normal vector at each point by using the three dimensional coordinates of points. The normal vectors are then clustered into several groups according to similarity. The RANSAC algorithm is applied to separate out planes. The domain knowledge helps to determine the wall among planes in an indoor environment. This paper concludes with experimental results that show performance of the proposed method in various experimental environment.

• Journal of the Korean housing association
• /
• v.19 no.3
• /
• pp.105-115
• /
• 2008

This study examines and analyzes a variety of apartment roof style for 147 apartment complexes built in the Gwangju metropolitan city in order to determine the style that is most preferred. The results of this study are as follows. Most of apartment houses built in the Gwangju metropolitan city are 11 to 15 stories followed by apartments that have less than 5 stories, with fewer apartments that have 16 to 20 stories. According to roof styles, the eyebrow roof A type is the most common, followed by the plane roof A type, the sloped roof B type and the sloped roof C type, while 2/3 of all roof types have either an eyebrow roof A type or a plane roof A type. Using images of these roof types to determine those that are preferred, the decorative roof C type is most preferred, followed by the sloped roof B and C types. According to recognition of adjective pairs, decorative roof C type showed a higher recognition for the categories of unique, decorative, three dimensional and novel, the sloped roof B type showed a higher recognition for the categories of three dimensional, decorative and structured while the sloped roof C type showed a higher recognition in the decorative, novel, varied and three dimensional categories. In the correlations between image preference and recognition scale of roof styles of apartment houses, decorative roof C type showed a significant correlation between adjective pairs with the calm image, the sloped roof B type with the intimate image, while the sloped roof C type showed a correlation between static and ordered with the easy image. Therefore, for the design of future apartment roofs, decorative roof C type requires more consideration of visual aspects that are related to a sense of unity, while further morphological factors needs to be adopted with sloped roof B and C types.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2013.05a
• /
• pp.1049-1050
• /
• 2013

• Journal of Biomedical Engineering Research
• /
• v.3 no.2
• /
• pp.119-122
• /
• 1982

This paper presents the principles of image formation in NMR(Nuclear Magnetic Resonance) tomography. NMR tomographic imaging is a newly emerging, noninvasive, three-dimensional imaging technique. This new technique is an interdisciplinary science which encompasses the latest technologies in electrical, electronics, computers, physics, chemistry, mathematics, and medical sciences.