• Journal of KIBIM
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• v.13 no.4
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• pp.64-73
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• 2023

This study introduces a method of estimating the 3D coordinates of structural damage from the detection results of visual inspection provided in 2D image coordinates using sensing data of UAV and 3D shape information of BIM. This estimation process takes place in a virtual space and utilizes the BIM model, so it is possible to immediately identify which member of the structure the estimated location corresponds to. Difference from conventional structural damage localization methods that require 3D scanning or additional sensor attachment, it is a method that can be applied locally and rapidly. Measurement accuracy was calculated through the distance difference between the measured position measured by TLS (Terrestrial Laser Scanner) and the estimated position calculated by the method proposed in this study, which can determine the applicability of this study and the direction of future research.

• Journal of Urban Science
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• v.13 no.1
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• pp.33-42
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• 2024

In recent years, drones are expanding their use as highly efficient smart support equipment in all industries, including military as well as urban engineering planning and design, construction, In particular, the advancement of drones and GNSS(global navigational satellite system) positioning services, the high efficiency of visible color image RGB sensors, and various selective convergence between thermal infrared sensors and lidar scanning visibility sensors are becoming a key source of spatial information acquisition in the field of construction information modeling(BIM) and 3D digital twin modeling. This study seeks to improve the efficiency of field and office works in drone aerial photography in 3D modeling of urban facilities. For these, after acquiring the 3D location of the drone aerial photography point in two positioning modes, standard GNSS surveying and GNSS RTK precise positioning, the 3D productions were reproduced through the SfM(structure from motion) image analysis process, and the accuracy and efficiency of the work process were compared and considered. As a result of the study, when GNSS RTK precision positioning (VRS ; virtual reference service) is applied during outdoor filming, it was possible to reproduce and demonstrate the effectiveness of the digital twin modeling within the allowable range by omitting the GNSS surveying for additional ground control points and geo-tagging for the real-world model conversion of 3D image analysis results in image processing.

• Journal of Computing Science and Engineering
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• v.4 no.4
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• pp.368-387
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• 2010

We propose a novel method for the registration of 3D CT scans to 2D endoscopic images during the image-guided medialization laryngoplasty. This study aims to allow the surgeon to find the precise configuration of the implant and place it into the desired location by employing accurate registration methods of the 3D CT data to intra-operative patient and interactive visualization tools for the registered images. In this study, the proposed registration methods enable the surgeon to compare the outcome of the procedure to the pre-planned shape by matching the vocal folds in the CT rendered images to the endoscopic images. The 3D image fusion provides an interactive and intuitive guidance for surgeon by visualizing a combined and correlated relationship of the multiple imaging modalities. The 3D Magic Lens helps to effectively visualize laryngeal anatomical structures by applying different transparencies and transfer functions to the region of interest. The preliminary results of the study demonstrated that the proposed method can be readily extended for image-guided surgery of real patients.

• Korean Journal of Construction Engineering and Management
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• v.25 no.3
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• pp.37-46
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• 2024

Recently, 3D laser scanning technology, which can collect accurate and quick information on phenomena, has been attracting attention among smart construction technologies. 3D laser scanning technology can obtain information most similar to reality at construction sites. In this study, we would like to apply a new member identification method to an actual building and present the possibility of applying point cloud data, which can be collected using 3D laser scanning technology, to measuring progress at construction sites. In order to carry out the research, we collected location information for component identification from BIM, set a recognition margin for the collected location information, and proceeded to identify the components that make up the building from point cloud data. Research results We confirmed that the columns, beams, walls, and slabs that make up a building can be identified from point cloud data. The identification results can be used to confirm all the parts that have been completed in the actual building, and can be used in conjunction with the unit price of each part in the project BOQ for prefabricated calculations. In addition, the point cloud data obtained through research can be used as accurate data for quality control monitoring of construction sites and building maintenance management. The research results can contribute to improving the timeliness and accuracy of construction information used in future project applications.

• Journal of Korean Neurosurgical Society
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• v.47 no.3
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• pp.185-190
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• 2010

Objective : The aneurysm remnants rate was evaluated via three-dimensional digital subtraction angiography (3D-DSA) in the postoperative evaluation of clipped aneurysms. Methods : Data on surgically clipped aneurysms of anterior circulation obtained via postoperative 3D-DSA from February 2007 to March 2009 were gathered. The results of the postoperative 3D-DSA and of two-dimensional digital subtraction angiography (2D-DSA) for the detection of aneurysm remnants were compared, and an investigation was performed as to why 2D-DSA had missed some aneurysm remnants that were detected in the 3D-DSA. Various surgical factors that revealed aneurysm remnants in the 3D-DSA were also evaluated. Results : A total of 39 neck remnants of 202 clipped aneurysms (19.3%) were confirmed in 3D-DSA, and these were classified according to Sindou's classification of aneurysm remnants. Patients with only a neck remnant found in the 3D-DSA represented 17.3% (35/202 aneurysms) of the whole series, and those with a residuum of neck plus sac found in the 3D-DSA represented 1.9% (4/202 aneurysms). The causes of aneurysm remnants were no full visualization (14/39, 35.9%), parent and perforator artery protection (10/39, 25.6%), clip design problems (8/39, 20.5%), and broadnecked aneurysm (7/39, 17.9%). Conclusion : Patients with ${\leq}2$mm aneurysm remnants showed an increased risk of undetectable aneurysm remnants in the 2D-DSA. The most frequent location of the missed aneurysm in 2D-DSA was the anterior communicating artery. 3D-DSA showed more aneurysm remnants than what is indicated in the existing literature, the 2D-DSA.

• Journal of Information Display
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• v.6 no.4
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• pp.16-25
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• 2005

In this paper, a new 3D object tracking system using the disparity motion vector (DMV) is presented. In the proposed method, the time-sequential disparity maps are extracted from the sequence of the stereo input image pairs and these disparity maps are used to sequentially estimate the DMV defined as a disparity difference between two consecutive disparity maps Similarly to motion vectors in the conventional video signals, the DMV provides us with motion information of a moving target by showing a relatively large change in the disparity values in the target areas. Accordingly, this DMV helps detect the target area and its location coordinates. Based on these location data of a moving target, the pan/tilt embedded in the stereo camera system can be controlled and consequently achieve real-time stereo tracking of a moving target. From the results of experiments with 9 frames of the stereo image pairs having 256x256 pixels, it is shown that the proposed DMV-based stereo object tracking system can track the moving target with a relatively low error ratio of about 3.05 % on average.

• Anatomy and Cell Biology
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• v.55 no.1
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• pp.55-62
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• 2022

The infraorbital nerve block is used for mid-facial anesthesia. We aim to determine the location of infraorbital foramen (IOF) and accessory infraorbital foramen (AIOF) with reference to anterior nasal spine (ANS) and the lowest point of zygomaticomaxillary junction (Z) and assess the accuracy of the predictive method. Two hundred and sixteen dry skulls were examined. A reference line was drawn from ANS to Z (line A) and its length was measured (distance A). The location of IOF was predicted by using the mean vertical distance from IOF to line A (line B) which was 15.14±1.99 mm and the mean ratio of the distance between ANS and the intersecting point of line B and line A (distance D) to distance A (D:A) which was 63.35%±3.90%. Eighty-six AIOFs were found. Most of them located superomedial to IOF, except for 3 AIOFs which located in the inferolateral position. For localization the AIOF, the mean vertical distance was 19.34±3.36 mm and the mean ratio was 51.8%±5.90%. No statistically significant difference of the predicted distances for both foramens was found between sex and sides. The accuracy of the predictive method was assessed in 15 embalmed cadavers. Predicted IOFs were 50% accurate and the mean distance error of the predicted IOF was 1.10±1.44 mm lateral and 0.59±1.39 mm inferior to the exact IOF. Therefore, this study provides an alternative method for localization of IOF and AIOF which could be useful in clinical settings.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.333-336
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• 2008

The groove rolling is a process that transforms the bloom or billet into a shape with circular section through a series of rolling. Inhibition of surface defect generation in groove rolling is a matter of great importance and therefore many research groups proposed a lot of models to find the location of surface defect initiation. In this study, we propose a model for maximum shear stress ratio over equivalent strain to catch the location of surface defect onset. This model is coupled with element removing method and applied to box groove rolling of POSCO No. 3 Rod Mill. Results show that proposed model in this study can find the location of surface defect initiation during groove rolling when finite element analysis results is compared with experiments. The proposed criterion has been applied successfully to design roll grooves which inhibits the generation of surface defect.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1766-1768
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• 2004

This paper describes the prediction of location of PD signals in GIS using the difference in the measured time between first and second wave arrival by the external-type PD sensors. It is well accepted that the electromagnetic wave in GIS propagates at the velocity of $3{\times}10^8$m/s. Consequently, we could identify the location of PD with high accuracy. The experience at the fields and the problems for the judgment are also discussed in detail.

• The Journal of the Acoustical Society of Korea
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• v.27 no.3E
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• pp.104-111
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• 2008

Recently, a method for robust time reversal focusing has been introduced to extend the period of stable focusing in time-dependent ocean environments [S. Kim et al., J. Acoust. Soc. Am. 114, 145-157, (2003)]. In this study, concept of focal-size broadening based on waveguide invariant theory in an ocean time reversal acoustics is described. It is achieved by imposing the multiple location constraints. The signal vector used in multiple location constraints are found from the theory on waveguide invariant for frequency band corresponding the extended focal range. The broadening of foci in an ocean waveguide can play an important role in the application of time reversal processing, particularly to the underwater acoustic communication with moving vehicles. The proposed method is demonstrated in the context of the underwater acoustic communication from the transmit/receive array (TRA) to a slowly moving vehicle.