• Journal of the Korean Society of Industry Convergence
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• v.18 no.2
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• pp.90-98
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• 2015

This research propose with image-based visual a new approach to design a feedback control of mobile robot. because mobile robot must be recharged periodically, it is necessary to detect and move to docking station. Generally, laser scanner is used for detect of position of docking station. CCD Camera is also used for this purpose. In case of using camera, the position-based visual servoing method is widely used. But position-based visual servoing method requires the accurate calibration and it is hard and complex work. Another method using cameras is inmage-based visual feedback. Recently, image based visual feedback is widely used for robotic application. But it has a problem that cannot have linear trajectory in the 3-dimensional space. Because of this weak point, image-based visual servoing has a limit for real application. in case of 2-dimensional movement on the plane, it has also similar problem. In order to solve this problem, we point out the main reason of the problem of the resolved rate control method that has been generally used in the image-based visual servoing and we propose an image-based visual feedback method that can reduce the curved trajectory of mobile robot in th cartesian space.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1679-1684
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• 2004

This paper introduces a novel approach that can provide the three dimensional information on the movement of a spreader by using two CCD cameras and a laser distance sensor, which enables an ALS (Automatic Landing System) to be used for yard cranes at a harbor. So far a kind of 2D Laser scanner sensor or laser distance measuring units are used as corner detectors for the geometrical matching between the spreader and a container, which provides only 2D information which is not enough for an accurate and fast ALS system required presently. In addition to this deficiency in performance, the price for the system is too high to be adopted widely for the ALS. Therefore, to overcome these defects, a novel method to acquire the three dimensional information for the movement of a spreader including skew and sway angles is proposed using two CCD cameras and a laser distance sensor. To show the efficiency of proposed algorithm, real experiments are performed to show the accuracy improvement in distance measurement by fusing the sensory information of CCD camera and laser distance sensor.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.2
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• pp.167-184
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• 1999

The purpose of this study was to evaluate and compare the at of denture bases processed by injection pressing technic using laser scanner of reverse engineering technic. The auther duplicated 20 maxillary edentulous models and 20 mandibular edentulous models, which were scanned on HYSCAN 45C 3D BCANNER(Hymarc Co., Canada). The scanned data were stored in the personal computer using SURFACER (Imageware Co. U.S.A.) software program. After 40 dentures were cured by PERform Inkovac system, SR-Ivocap system, Palajet system, and Sulfon system, they were stored in water at room temperature fir 24 hours. The dentures were scanned on HYSCAN 45C 3D SCANNER(Hymarc Co., Canada). The scanned data were stored in the personal computer using SURFACER (Imageware Co., U.S.A.) software program. By overlapping two images using the same program, the fit between two surfaces was scaled by positive and negative errors. The obtained results were as follows 1. In the upper denture, most of the positive errors occurred on the lingual side of anterior alveolar ridge and the negative errors were on the flange of denture bases. 2. In the lower denture, most of the positive errors occurred on the inner side of lingual flange and the negative errors were on the border of anterior labial flange areas, 3. There were no statistical differences among the positive errors of the four types of injection denture curing methods and also no statistical differences between negative errors except only in negative maximum errors. 4. In PERform system and SR-Ivocap system, they have the tendency of inaccurate at of lower denture bases comparing to that of upper denture bases. 5. The negative error scales were greater than the positive error scales in all types of injection denture curing methods.

• Imaging Science in Dentistry
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• v.47 no.2
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• pp.117-122
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• 2017

Purpose: The aim of this study was to compare the use of 3-dimensional (3D) laser scanning and cone-beam computed tomography (CBCT) as methods of root surface measurement. Materials and Methods: Thirty teeth (15 maxillary first premolars and 15 mandibular first premolars) from 8 patients who required extractions for orthodontic treatment were selected. Before extraction, pre-treatment CBCT images of all the patients were recorded. First, a CBCT image was imported into simulation software (Mimics version 15.01; Materialise, Leuven, Belgium) and the root surface area of each tooth was calculated using 3-Matic (version 7.01, Materialise, Leuven, Belgium). After extraction, all the teeth were scanned and the root surface area of each extracted tooth was calculated. The root surface areas calculated using these 2 measurement methods were analyzed using the paired t-test (P<.05). Correlations between the 2 methods were determined by calculating the Pearson correlation coefficient. The intraclass correlation coefficient(ICC) was used to assess intraobserver reliability. Results: The root surface area measurements ($230.11{\pm}41.97mm^2$) obtained using CBCT were slightly greater than those ($229.31{\pm}42.46mm^2$) obtained using 3D laser scanning, but not significantly (P=.425). A high Pearson correlation coefficient was found between the CBCT and the 3D laser scanner measurements. The intraobserver ICC was 1.000 for 3D laser scanning and 0.990 for CBCT. Conclusion: This study presents a novel CBCT approach for measuring the root surface area; this technique can be used for estimating the root surface area of non-extracted teeth.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.725-731
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• 2020

In mineral resource development, resource exploration is a task to find economical minerals on the surface and underground, and the success rate is low compared to the development and production stages, and it is necessary to collect a lot of data through exploration and accurately analyze the collected information. In this study, mine spatial information was constructed using a 3D (Three-dimensional) laser scanner, and accuracy evaluation was performed to obtain a maximum deviation of 0.140 m and an average of 0.095 m in the X, Y and Z directions, and the possibility of utilizing the construction of mine geospatial information through a 3D laser scanner could be presented. In addition, the ore body modeling was performed by applying the interpolation method of the ore body section using the resource exploration results. The ore body modeling result was superimposed with the modeling result of the mine geospatial information built through the 3D laser scanner to construct the ore body modeling result based on the precise mine geospatial information. The results of ore body modeling based on mine geospatial information built through research can increase the ease of data interpretation and the accuracy of the calculated data, which will greatly increase the efficiency of work related to mineral resource development and mine damage prevention in the future.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.3
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• pp.135-140
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• 2013

In this paper, we discussed about the volume monitoring system of a landfill facility. We proposed the waste volume calculation method using the point cloud of the surface of three dimensional object by measurement of the point cloud by the three dimensional scanner, which is based upon the robot technique. This computes not only the quantity of waste volume for continuos monitoring but also it helps not only to predict the evaluation factor of the usable age of a landfill. facility. Furthermore, the measuring system of waste volume was applied to the landfill facility in Ansung city.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.11
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• pp.64-72
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• 1996

This paper is aimed to develop an optical method for measuring 3-dimensional shapes of specular objects having curved surfaces. The existing methods measuring the shapes of specular objects have several common disadvantages: they may not work properly if the surface is highly specular like mirror surface or if the reflectance property is not uniform over the surface. And, they often require the a priori knowledege about the surface reflectance. To overcome these disadvantages, the measurement using double pass retroreflection method is proposed in this paper. For this measurement principle, an experimental measuring system is designed and prepared which is composed of a galvanometer scanner, a beam splitter, a laser source, a CCD camera, and a reflector made of retroreflective material. To verify the effectiveness of the measurement system a series of experiments are performaed for various specular objects. The results observed from the experiments show that the developed optical sensing system can be an effective mean of measuring the 3-D shapes of specular objects.

• Archives of Plastic Surgery
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• v.35 no.3
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• pp.303-308
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• 2008

Purpose: The purpose of this study is to develop three-dimensional computerized anthropometry(3DCA) and to compare its reliability and accuracy 3DCA with manual anthropometry(MA) for measurement of lips and nasal deformities in unilateral cleft lips and palate(UCLP) patients. Methods: Samples were consisted of six UCLP patients whose facial plaster models were available immediately before and 3 months after the cleft lip surgery. MA of the facial plaster models was carried out using an electronic caliper. In 3DCA, three-dimensional auto-measuring program was used to digitize landmarks and to measure three-dimensional virtual facial models (3DVFM), which was generated with a laser scanner and 3D virtual modeling program. Intraclass correlation coefficients(ICC) were calculated to evaluate reliability and reproducibility of the variables in both methods, and Wilcoxon's signed rank test was done to investigate the difference in values of the same variables of facial models of each patient between two methods. Results: All ICC values were higher than 0.8, so both methods could be considered reliable. Although most variables showed statistical differences between two methods(p<0.05), differences between mean values were very small and could be considered not significant in clinical situation. Conclusion: In clinical situation, 3DCA can be an objective, reliable and accurate tool for evaluation of lips and nasal deformities in the cleft patients.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1324-1333
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• 2010

This paper is used in a recent civil engineering field in three-dimensional laser-meter tiles using thermal imaging cameras for the weathered rock slopes precisely measured indirectly, to the degree that began in the will. In the field is difficult to access the degree of weathering of the rock slope to the existing direct way to compensate for the shortcomings of 3D Terrestrial Laser Scanner and weathering characteristics of rocks using thermal imaging cameras to get the information to analyze the degree of rock weathering is. Intensity of 3D TLS and the thermal camera with image analysis to analyze the degree of weathering of bedrock in the field of core drilling targeting indoor laboratory tests were analyzed through the study. Granite, gneiss, sandstone, much of the cancerous samples, each experiment has a 40 per category, each of which 30 were used to analyze the data collected. That degree of rock weathering, the rock, depending on the strength of the Intensity values can change, depending on the level of thermal imaging camera, also weathered the changes in temperature could see. Intensity is the strength of weak rocks, the more value decrease, the temperature of the thermal imaging camera through the swell Intensity and notice that the temperature had an inverse relationship. Intensity value of the low strength of weak rock, but the value came out of the rocks have been proved to be largely dependent on the contrast. The contrast of the surface rocks are weathered dark Intensity values lower temperature to swell the contrary, the degree of weathering can be distinguished.

• Journal of dental hygiene science
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• v.15 no.2
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• pp.226-231
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• 2015

The purpose of this study was to evaluate the accuracy of model according to three types of dental scanner. A maxillary acrylic model was prepared and duplicated 10 times by silicone impression materials. Corresponding working casts were formed from scannable stone and got a 3-dimensional digital models using three different scanners. The distance of each measurement region was measured using vernier calipers and the respective program. One-way ANOVA and the Tukey honestly significant difference post hoc test (${\alpha}=0.05$) was performed using IBM SPSS Statistics 21.0. Overall, the stone cast is smaller than the digital models in measurement distance. And measuring point value of laser scanner showed the most similar values and measurement points value of digital vernier calipers. Digital model of white light scanner showed similar values in the measurement points value of the blue light scanner. In conclusion, the laser scanner showed the best accuracy among the three types of dental scanner. However, the difference between the digital models and the stone cast can be accommodated in making prostheses. Thereby, three types of dental scanner are available in a clinically acceptable range.