• Journal of Korea Society of Industrial Information Systems
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• v.15 no.4
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• pp.47-52
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• 2010

This paper describes a visualization technique that animates geometrical defect data that are extracted using a magnetic flux leakage (MFL) operating system on nondestructive evaluation (NDE). Since data are collected from different locations and often not regular, the data must be converted to the standard format that is used within the pipeline in visualization procedures. In order to navigate inside of the pipeline, 3D virtual objects are generated and are able to explore the pipeline continuously. The major objectives of this paper are to characterize, generate general shape of defects, and enable computer interaction in virtual environment. Pipeline navigation system (PNS) has introduced the framework for interactive visual applications based upon the principles of modeling 3D objects. PNS presents some preliminary efforts to enable the user to interact human and computer with each other.

• Journal of KIISE:Software and Applications
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• v.35 no.2
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• pp.118-127
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• 2008

In this paper, we propose a method for construction of robust 3D statistical shape model in the mandible CT datasets. Our method consists of following four steps. First, we decompose a 3D input shape Into patches. Second, to generate a corresponding shape of a floating shape, all shapes in the training set are parameterized onto a disk similar to the patch topology. Third, we generate the corresponding shape by one-to-one mapping between the reference and the floating shapes. We solve the problem failed to generate the corresponding points near the patch boundary Finally, the corresponding shapes are aligned with the reference shape. Then statistical shape model is generated by principle component analysis. To evaluate the accuracy of our 3D statistical shape model of the mandible, we perform visual inspection and similarity measure using average distance difference between the floating and the corresponding shapes. In addition, we measure the compactness of statistical shape model using the modes of variation. Experimental results show that our 3D statistical shape model generated by the mandible CT datasets with various characteristics has a high similarity between the floating and corresponding shapes and is represented by the small number of modes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.695-698
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• 2014

As most the scanning systems developed until now provide radiation scan plane images of the inspected objects, there has been a limitation in judging exactly the shape of the objects inside a logistics container exactly with only 2-D radiation image information. Two 2-dimensional radiation images which have different disparity values are acquired from a newly designed stereo image acquisition system which has one additional line sensor to the conventional system. Using a matching algorithm the 3D reconstruction process which find the correspondence between the images is progressed. In this paper, we proposed a new volume based 3D reconstruction algorithm and experimental results show the proposed new volume based reconstruction technique can provide more efficient visualization for cargo inspection. The proposed technique can be used for the development of the high speed and more efficient non-destructive auto inspection system.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.110-116
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• 2007

This paper presents a new technique to implement the real-time recognition for shapes and model number of parts based on an active vision approach. The main focus of this paper is to apply a technique of 3D object recognition for non-contacting inspection of the shape and the external form state of precision parts based on the pattern recognition. In the field of computer vision, there have been many kinds of object recognition approaches. And most of these approaches focus on a method of recognition using a given input image (passive vision). It is, however, hard to recognize an object from model objects that have similar aspects each other. Recently, it has been perceived that an active vision is one of hopeful approaches to realize a robust object recognition system. The performance is illustrated by experiment for several parts and models.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.3
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• pp.157-166
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• 2018

Purpose: This study was aimed to compare the consistency between the custom abutment design and the output in two CAD software programs. Materials and Methods: Customized abutments were designed by using 3Shape Dental System CAD software and Delta9 CAD software on a plaster model with implants (CRM STL file). After milling of the designed abutments, the abutments were scanned with a contact method scanner (Test STL file). We overlaid the Test STL file with each CRM STL file by using inspection software, and then compared the milling reproducibility by measuring the output error of the specimens from each CAD software program. Results: The Delta9 showed better milling reproducibility than 3Shape when comparing the milling errors obtained with a full scan of all specimens (P < .05) and also when comparing the axial wall region specifically according to the axial angle. With 0.9 mm marginal radius, the Delta9 showed better consistency between the design and the output than 3Shape (P < .05). While, anti-rotation form had no significant difference in error between the two systems. When cumulative errors were compared, the Delta9 showed better milling reproducibility in almost cases (P < .05). Conclusion: Delta9 showed a significantly smaller error for most of the abutment design options. This means that it is possible to facilitate generation of printouts with reliable reproducibility and high precision with respect to the planned design.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.6
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• pp.738-744
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• 2011

The reliability of blade root fixing section is required to endure the centrifugal force and vibration stress for the last stage blade of steam turbine in thermal power plant. Most of the domestic steam turbine last stage blades have finger type roots. The finger type blade is very complex, so the inspection had been performed only on the exposed fixing pin cross-section area due to the difficulty of inspection. But the centrifugal force and vibration stress are also applied at the blade root finger and the crack generates, so the inspection method for finger section is necessary. For the inspection of root finger, inspection points were decided by simulating ultra-sonic path with 3D modeling, curve-shape probe and fixing jig were invented, and the characteristics analysis method of ultrasonic reflection signal and defect signal disposition method were invented. This invented method was actually executed at site and prevented the blade liberation failure by detecting the cracks at the fingers. Also, the same type blades of the other turbines were inspected periodically and the reliability of the turbine increased.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.1
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• pp.166-182
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• 1998

The purposes of this study are to evaluate the Korean mandibular dental arch and classify the mandibular dental arch shape and size based on the incisal angle, canine angle, inter second molar width and height. In this study the mandibular study models were fabricated using irreversible hydrocolloid impression material from 225 volunteers with a mean age 23.62 (range 19-29). And the study models were measured with 3-dimensional measuring device and the mandibular dental arch was classified by means of K-means clustering method and visual inspection, then obtained data were analyzed with t-test for the statistical analysis. The results were as follows ; 1. The average canine height was 5.19mm(s.d. 1.17) in both sex, 5.34mm in male, and 4.95mnm in female. And the sexual difference was significant($0). 2. The average second molar height was 39.81mm(s.d. 2.44) in both sex, 40.19mm in male, and 39.21mm in female. And the sexual difference was significant($0). 3. The average inter-canine width was 27.16mm(s.d. 1.78) in both sex, 27.41mm in male, and 26.77mm in female. And the sexual difference was significant($0). 4. The average inter-first molar width was 46.93mm(s.d. 2.67) in both sex, 47.72mm in male, and 45.7mm in female. And the sexual difference was significant($0). 5. The inter-second molar width was average 56.09mm(s.d. 3.01) in both sex, 57.24mm in male, and 54.32mn in woma. And the sexual difference was significant($0). 6. The arch form was classified into three shapes based on the incisal and canine angle. V-shape showed $124.88^{\circ}$ of incisal angle and $141.64^{\circ}$ of canine angle, U-shape showed $152.76^{\circ}\;and\;125.35^{\circ}$, and O-shape showed $138.03^{\circ}\;and \;33.66^{\circ}$ respectively. Each shape distribution was that the V-shape was 14.2%, the U-Shape was 14.7%, and the O-shape was 71.1% of the 225 study models. 7. It was thought that the use of second molar width is more reasonable than height for classifying the dental arch size. The arch size was classified into four sizes based on the second molar width. Size 1 showed range of 42.24-48.23mm, size 2 showed 48.24-54.23mm, size 3 showed 54.24-60.23mm, and size 4 showed 60.24-66.23mm respectively. Each arch size distribution was that the size 1 was 1.3%, the size 2 was 27.1%, the size 3 was 63.6%, and the size 4 was 8.0% of the 225 study models.

• Korean Journal of Computational Design and Engineering
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• v.3 no.1
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• pp.22-30
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• 1998

The deflection yoke (DY) controls the direction of the electron beam that falls on the screen of the television monitor. Its quality depends on the shape and density of coils wound around the DY coil separator. Winding frames are used to make these coils, and therefore, their shapes are essential in making quality coils. A reverse engineering(RE) is applied to create the 3D model of the winding frame. It considerably shortens the design verification time and shows the level of accuracy that is feasible in the production mode. The paper explains each step of the reverse engineering process in detail.

• Journal of Technologic Dentistry
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• v.24 no.1
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• pp.73-81
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• 2002

Accurate acquisition of surface geometries such as machined surfaces, biological surfaces, and deformed parts have been very important technique in scientific study and engineering, expecially for system design, manufacturing and inspection. Two camera method is relatively simple with an acceptable accuracy. In this paper, a new method is studied to acquire 3D geometric data of the small object such as a die in stone model. When the devices, cameras, laser beam and object are in a perfect plane, the calculation becomes very simple with less error. But this paper shows that arbitrarily positioned system can also be used to obtain 3D data.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.264-267
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• 1996

This paper is aimed to develop a very reliable method for automatic inspection of the solder joints on PCBS. There have been lots of previous works using vision technologies, but they can not be used for inspecting BGA, FCA or other newly used devices. Thus we adopt X-ray technologies for solder joint inspection. We put our attention on reconstructing the 3D shapes of solder joints since it gives us the most detailed information on quality of solder joints. Laminography principle is used to reject the interferences from neighboring parts or leads. To verify the effectiveness of laminography, a simulation study is performed in the case of a solder joints on double sided PCB using.