• 한국지형공간정보학회:학술대회논문집
• /
• 1995.10a
• /
• pp.121-142
• /
• 1995

Using SPOT satellite imagery, 3 dimensional geographic information can be obtained from SPOT's oblique viewing image. Especially, SPOT provides high spatial resolution, adequate base/height ratio and stable orbit characteristics. In this paper, 3D terrain features were extracted using SPOT stereo image and also the techniques for generation of 3D graphic data were developed for the extracted terrain features. We developed computer programs to generate automatically 3D graphic files and to display geographic information on the computer screen. The results of this study may be effectively utilized for the development of 3D geographic information using satellite images.

• Proceedings of the KSRS Conference
• /
• 2002.10a
• /
• pp.407-407
• /
• 2002

The most widespread techniques for DEM generation are stereoscopy for optical sensor images and interfereometry for SAR images. These techniques suffer from certain sensor and processing limitations, which can be overcome by the synergetic use of both sensors and DEMs respectively. In this paper, different strategies for fusing SAR and optical data are combined to derive high quality DEM products. The filtering techniques, which take advantage of the complementary properties of SAR and stereo optical DEMs, will be applied for the fusion process. By taking advantage of the fact that errors of the DEMs are of different nature using the filtering technique, affected part are filtered and replaced by those of the counterpart and is tested with two sets of SPOT and ERS DEM, resulting in a remarkable improvement in DEM. for the analysis of results, the reference DEM is generated from digital base map(1:5000).

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.25 no.2
• /
• pp.157-163
• /
• 2007

Recently, industrialization of a country is accelerated and request of society infrastructure is raised so national land development is activity view. Accordingly, the search for a wide-ranging buried heritage do acted in large construction region. Because the buried heritage get buried in land that it is necessary to the precision search and research for a record and a preservation. Until now, Surveying techniques of a historic site have made status map, profile and cross section map through leveling survey, total-station survey and sketch of specialist. So, to solve problems existing relic survey or drawing making method have using digital camera these researches rapidly and economically obtain stereo image of object and present a technique that constructs 3D image model for digital photogrammetry method. Also, these researches construct 3D image model for record and preservation of a historic site through site test and in 3D and graphical express a historic site and support works that produce other maps if we need it. offer base data of GIS (Geographic Information System) to collect and analyze overall, information of a historic site.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.4
• /
• pp.1132-1140
• /
• 1997

In many vision tasks of the major obstacles is the specular highkight of smoth objects, which causes a misinterpretation of objects.This paper presents an dffcient algorithm for highight detection and object reconstruction, blsed on the theory of photometric stereo in which the location of highilight changes as the position of illumination source changes.Two images, referred to as base image and reference image.are sequentially taken with two different positionhs of the two images.The difference image is thresholded to detct the specular spike of the highlight.Then the specu-lar lobe around the specular spike is detected to reconstruct the object.The proposed algorithm can be applied to metals and dielectrics, regardlless of the surface chracteristics.This method can also be aplied to the case when the background is brighter than the object.

• The Journal of the Acoustical Society of Korea
• /
• v.30 no.4
• /
• pp.197-206
• /
• 2011

In this paper, we proposes the virtual sound source panning algorithm in the multichannel system. Recently, High-definition (HD) and Ultrahigh-definition (UHD) video formats are accepted for the multimedia applications and they provide the high-quality resolution pixels and the wider view angle. The audio format also needs to generate the wider sound field and more immersive sound effects. However, the conventional stereo system cannot satisfy the desired sound quality in the latest multimedia system. Therefore, the various multichannel systems that can make more improved sound field generation are proposed. In the mutichannel system, the conventional panning algorithms have acoustic problems about directivity and timbre of the virtual sound source. To solve these problems in the arbitrary positioned multichannel loudspeaker system, we proposed the virtual sound source panning algorithm using multiple vectors base nonnegative amplitude panning gains. The proposed algorithm can be easily controlled by the gain control function to generate an accurate localization of the virtual sound source and also it is available for the both symmetric and asymmetric loudspeakers format. Its performance of sound localization is evaluated by subjective tests comparing with conventional amplitude panning algorithms, e.g. VBAP and MDAP, in the symmetric and asymmetric formats.

• Journal of Broadcast Engineering
• /
• v.1 no.2
• /
• pp.176-187
• /
• 1996

This paper deals with the accurate estimation of 3- D pose (position and orientation) of a moving object with reference to the world frame (or robot base frame), based on a sequence of stereo images taken by cameras mounted on the end - effector of a robot manipulator. This work is an extension of the previous work[1]. Emphasis is given to the 3-D pose estimation relative to the world (or robot base) frame under the presence of not only the measurement noise in 2 - D images[ 1] but also the camera position errors due to the random noise involved in joint angles of a robot manipulator. To this end, a new set of discrete linear Kalman filter equations is derived, based on the following: 1) the orientation error of the object frame due to measurement noise in 2 - D images is modeled with reference to the camera frame by analyzing the noise propagation through 3- D reconstruction; 2) an extended Jacobian matrix is formulated by combining the result of 1) and the orientation error of the end-effector frame due to joint angle errors through robot differential kinematics; and 3) the rotational motion of an object, which is nonlinear in nature, is linearized based on quaternions. Motion parameters are computed from the estimated quaternions based on the iterated least-squares method. Simulation results show the significant reduction of estimation errors and also demonstrate an accurate convergence of the actual motion parameters to the true values.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.25 no.3
• /
• pp.239-247
• /
• 2007

The 3D spatial information projects have been processed and utilized in varied fields. However, the research of the 3D digital map for a role of national base map is not enough. The draft maps, which are raw data for generating 2D digital map, shows problems in generating 3D digital map. The objective of this research is to develop 3D digital map editing system for modifying and editing of 3D digital map from 2D vector and raster information such as a draft map, 2D digital map, DEM, aerial photo and so forth. This 3D digital map editing system was designed to include data structure of geometric and attribute object under provision of ISO/TC211 and OGC standard. This system was developed to implement the function of 3D stereo editing based on stereo viewing, 3D view editing based on projective, and 3D spatial operation. Using this system, 3D digital maps were able to be successfully produced from not only existing draft maps but also modified or edited draft maps and then application results were compared and analyzed.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.1178-1183
• /
• 2003

As personal robots coexist with a person with a role to help a person, while adapting various human life and environment, the personal robots have to accommodate frequently-changing or different-from-home-to-home environment. In addition, personal robots may have many kinds of different Kinematic configurations depending on the capabilities. Some may have a mobile base and others may have arms and a head. The motivation of this study arises from this not-well-defined home environment and varying Kinematic configuration. So the goal of this study is to develop a general control architecture for personal robots. There exist three major architectures; deliberative, reactive and hybrid. We found that these are applicable only for the defined environment with a fixed Kinematic configuration. Neither could accommodate the above two requirements. For the general solution, we propose a Supervised Hybrid Architecture (SHA), in which we use double layers of deliberative and reactive controls, distributed control with a modular design of Kinematic configurations, and real-time Linux OS. Deliberative and reactive actions interact through a corresponding arbitrator. These arbitrators help a robot to choose an appropriate architecture depending on the current situation to successfully perform a given task. The distributed control modules communicate through IEEE 1394 for the easy expandability. With a personal robot platform with a mobile base, two arms, a head and a pan-tilt stereo eye system, we tested the developed SHA for static as well as dynamic environments. For this application, we developed decision-making rules for selecting appropriate control methods for several situations of navigation task. Examples are shown to show the effectiveness.

• The Journal of Korean Academy of Prosthodontics
• /
• v.50 no.2
• /
• pp.85-91
• /
• 2012

Purpose: The object of this study was to determine if the low-priced alloy and metal UCLA abutment could be available for manufacturing bar-retained framework of implant prosthesis. Materials and methods: Bar structure was classified into 4 groups, The specimen of group 1 and 2 were based on casting high noble metal alloys and noble metal alloys with gold UCLA abutment. The specimen of group 3 and 4 were based on casting noble metal alloys and base metal alloys with metal UCLA abutment. Cast bar structure was installed in an acrylic resin model and only the screw on the hexed abutment side was tightened to 20 Ncm. On the opposite side, vertical discrepancy was measured with stereo microscope from front, back, and lateral side of the implant-abutment interface. One-way ANOVA was performed to analyze the marginal fit discrepancy. Results: One-way ANOVA test showed significant differences among all groups ($P$<.05) except for Group 1 and 3. Among them, difference between Group 1 and 2 was noticeable. Measured vertical discrepancies were all below $70{\mu}m$ except to Group 2. Conclusion: Base metal alloy and metal UCLA abutment could be used as an alternative to high-priced gold alloy for implant bar-retained framework.

• Tunnel and Underground Space
• /
• v.17 no.2 s.67
• /
• pp.139-151
• /
• 2007

Stereophotogrammetry is a method to extract information of an interested area by constructing a stereo-image from two or more photos. In this study, the stereophotogrammetry was adopted to obtain the joint orientation and trace length from a sampling window and its measurements were compared with the result by a clinocompass and measuring tape to evaluate the applicability of the stereophotogrammetry to rock joint survey. A commercial stereophotogrammetry program, ShapeMetriX 3D, was used for this purpose. Firstly, the accuracy of the measuring method using ShpaeMetrix 3D was evaluated by a model test. Secondly, joint orientations on a rock slope and tunnel were obtained by using ShapeMetriX 3D and compared with the measurement by a clinocompass. Finally. the effect of base-depth ratio in photographing was evaluated by comparing images with various base-depth ratios, and the usefulness of closed-up photographing on a rock exposure to increase the measurement accuracy was tested. The dip and dip direction of each model plane obtained by ShapeMetriX 3D showed an error ranged between $-5^{\circ}\;and\; 5^{\circ}$ on the basis of the results by the measuring tape. Base-depth ratio proved not to influence the analysis result by ShapeMetriX 3D if all the images were taken without any hidden area. The close-up photographing turned out useful to obtain the detailed images and therefore precise result when ShapeMetriX 3D was adopted.