• Progress in Medical Physics
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• v.28 no.3
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• pp.106-110
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• 2017

The variable density phantom fabricated with varying the infill values of 3D printer to provide more accurate dose verification of radiation treatments. A total of 20 samples of rectangular shape were fabricated by using the $Finebot^{TM}$ (AnyWorks; Korea) Z420 model ($width{\times}length{\times}height=50mm{\times}50mm{\times}10mm$) varying the infill value from 5% to 100%. The samples were scanned with 1-mm thickness using a Philips Big Bore Brilliance CT Scanner (Philips Medical, Eindhoven, Netherlands). The average Hounsfield Unit (HU) measured by the region of interest (ROI) on the transversal CT images. The average HU and the infill values of the 3D printer measured through the 2D area profile measurement method exhibited a strong linear relationship (adjusted R-square=0.99563) in which the average HU changed from -926.8 to 36.7, while the infill values varied from 5% to 100%. This study showed the feasibility fabricating variable density phantoms using the 3D printer with FDM (Fused Deposition Modeling)-type and PLA (Poly Lactic Acid) materials.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1574-1585
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• 2011

This paper proposes a real-time algorithm for speed limit sign recognition for advanced safety vehicle system. The proposed algorithm uses Block-DCT in extracting features from a given ROI(Region Of Interest) instead of using entire pixel values as in previous works. The proposed algorithm chooses parts of the DCT coefficients according to the proposed discriminant factor, uses correlation coefficients and variances among ROIs from training samples to reduce amount of arithmetic operations without performance degradation in classification process. The algorithm recognizes the speed limit signs using the information obtained during training process by calculating LDA and Mahalanobis Distance. To increase the hit rate of recognition, it uses accumulated classification results computed for a sequence of frames. Experimental results show that the hit rate of recognition for sequential frames reaches up to 100 %. When compared with previous works, numbers of multiply and add operations are reduced by 69.3 % and 67.9 %, respectively. Start after striking space key 2 times.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.6
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• pp.773-781
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• 2018

In recent years, a study of power-line inspection using an unmanned aerial vehicle (UAV) has been actively conducted. However, relevant studies have been conducting power-line inspection with an UAV operated by manual control, and they have developed just power-line detection algorithm on aerial images. To overcome limitations of existing research, we propose a drone-based power-line tracking system in this paper. The main contributions of this paper are to operate developed system under configured environment and to develop a power-line detection algorithm in real-time. Developed system is composed of the power-line detection and the image-based tracking control. To detect a power-line in real-time, a region of interest (ROI) image is extracted. Furthermore, clustering algorithm is used in order to discriminate the power-line from background. Finally, the power-line is detected by using the Hough transform, and a center position and a tilt angle are estimated by using the Kalman filter to control a drone smoothly. We design a position controller and an attitude controller for image-based tracking control, and both controllers are designed based on the proportional-derivative (PD) control method. The interaction between the position controller and the attitude controller makes the drone track the power-line. Several experiments were carried out in environments where conditions are similar to actual environments, which demonstrates the superiority of the developed system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.8
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• pp.1885-1894
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• 2014

There are various high-performance algorithms in the area of the existing VDSs (vehicle detection systems). However, they requires a large amount of computational time-complexity and their systems generally are very expensive and consumes high-power. This paper proposes real-time traffic information detection algorithm that can be applied to low-cost, low-power, and open development platform such as Android. This algorithm uses a vehicle's sub-shadow to set ROI(region of interest) and to count vehicles using a location of the sub-shadow and the vehicle. The proposed algorithm is able to count the vehicles per each roads and each directions separately. The experiment result show that the detection rate for going-up vehicles is 94.1% and that for going-down vehicles is 97.1%. These results are close to or surpasses 95%, the detection rate of commercial loop detectors.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.7
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• pp.629-639
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• 2016

Batch process TRN(Terrain Relative Navigation) using an altimeter is a technique to correct position by correlating a series of periodically measured terrain height profile and terrain height candidate profile of the DEM(Digital Elevation Map). However, it is generally known that the performance of TRN is degraded when measured terrain height profile and terrain height candidate profiles of the DEM are similar at hill or repetitive terrain. In this paper, area based terrain slope roughness index[11] is applied and area based terrain curvature roughness index which can detect similarity of terrain in ROI(Region Of Interest) is proposed to overcome this problem. Applying terrain roughness indexes to terrain relative navigation system of lunar lander, it is shown that TRN using area based terrain roughness results in improved performance compared to conventional trajectory based method through simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.5
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• pp.691-700
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• 2021

The IP cameras have rapidly replaced the analog CCTVs as the cameras have the advantages of not only being able to remotely monitor, but also supplying power through the UTP cable, In this paper, we introduce the protocol architecture of the ONVIF standard which is widely applied to the IP camera and other Internet protocols to support it, and implement the ONVIF Device on a commercial board. Although these functions can be controlled by the Client (PC), several functions such as privacy masks, temperature display of the thermal camera, and ROI (Region of Interest) are implemented through a web viewer on the device. Through the experiment, the functions of ONVIF Profile S and web viewer are verified through SOAP messages exchanged between Device (IP camera) and Client program and streamed images.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.793-803
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• 2013

This study was performed to determine the usefulness of scanpath similarity analysis as one of new web usability testing. The 5 websites of public institutions were used and 15 students participated. First of all, eye movements were tracked and visual appeal ratings were measured as participants freely viewed each website for 3 seconds. Subsequently in continuously tracking the eye movements we asked the participants to perform 17 missions. Finally, in interview the participants rated on satisfaction, awareness, and mission difficulty. Results of this study showed that scanpath similarity had a significant relationship with both the visual appeal ratings(first impression) and the satisfaction. In other words, higher the visual appeal ratings were related to higher scanpath similarity. This result showed that measurement such as scanpath similarity of eye movements could become an objective index for usability testing instead of subjective evaluation such as the satisfaction. We discussed possibility that the usability testing by using the scanpath similarity with both fixation and duration on eye movements will find more appropriately inference on observers' experiences in websites.

• Journal of Korea Multimedia Society
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• v.16 no.7
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• pp.870-878
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• 2013

In this paper, we propose a novel fingerprint classification method to enhance the accuracy and efficiency of the fingerprint identification system, one of biometrics systems. According to the previous researches, fingerprints can be categorized into the several patterns based on their pattern of ridges and valleys. After construction of fingerprint database based on their patters, fingerprint classification approach can help to accelerate the fingerprint recognition. The reason is that classification methods reduce the size of the search space to the fingerprints of the same category before matching. First, we suggest a method to extract region of interest (ROI) which have real information about fingerprint from the image. And then we propose a feature extraction method which combines gray level co-occurrence matrix (GLCM) and wavelet features. Finally, we compare the performance of our proposed method with the existing method which use only GLCM as the feature of fingerprint by using the multi-layer perceptron and support vector machine.

• Korean Journal of Remote Sensing
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• v.32 no.6
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• pp.693-701
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• 2016

To make a mosaicked image, we need to estimate the geometric relationship between individual images. For such estimation, we needs tiepoint information. In general, feature-based methods are used to extract tiepoints. However, in the case of textureless images, feature-based methods are hardly applicable. In this paper, we propose a frequency domain matching method for automated mosaicking of textureless images. There are three steps in the proposed method. The first step is to convert color images to grayscale images, remove noise, and extract edges. The second step is to define a Region Of Interest (ROI). The third step is to perform phase correlation between two images and select the point with best correlation as tiepoints. For experiments, we used GOCI image slots and general frame camera images. After the three steps, we produced reliable tiepoints from textureless as well as textured images. We have proved application possibility of the proposed method.

• Imaging Science in Dentistry
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• v.48 no.2
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• pp.103-109
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• 2018

Purpose: To analyze cone-beam computed tomography (CBCT) use, indications, and exposure parameters in San $Jos{\acute{e}}$, Costa Rica. Materials and Methods: A cross-sectional study was performed. All CBCT examinations over a period of 6 months at 2 radiological centers in San $Jos{\acute{e}}$, Costa Rica were evaluated. The examinations were performed with Veraview EPOC X550 and Veraviewepocs 3D R100 equipment. The patients' age and sex, clinical indication for CBCT, region of interest (ROI), repeat examinations, specialty of the referring dentist, field-of-view (FOV), tube voltage (kV), tube current (mA), and radiation dose (${\mu}Gy$) were evaluated. Patients were classified by age as children (${\leq}12years$), adolescents(13-18 years), and adults(${\geq}19years$). Results: The mean age of the 526 patients was 49.4 years. The main indications were implant dentistry and dental trauma. The most frequent ROIs were posterior, while anterior ROIs were much less common. The highest percentage of repeat examinations was in children. Fifty-six percent of the referring dentists were specialists. The most commonly used FOV was small. The mean tube voltage and current were 79.8 kV and 7.4 mA for Veraview EPOC X550 and 89.9 kV and 6 mA for Veraviewepocs 3D R100, respectively. The mean doses for children, adolescents, and adults were $6.9{\mu}Gy$, $8.4{\mu}Gy$, and $7.8{\mu}Gy$, respectively. Conclusion: Although CBCT was most commonly used in adults for implant dentistry, most repeat examinations were in children, and the highest mean dose was in adolescents. Additional dose optimization efforts should be made by introducing low-dose protocols for children and adolescents.