• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.180-181
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• 2018

JPEG is a most widely used standard image compression technology. This research introduces the JPEG image compression algorithm and describes each step in the compression and decompression. Image compression is the application of data compression on digital images. The DCT (discrete cosine transform) is a technique for converting a time domain to a frequency domain. First, the image is divided into 8 by 8 pixel blocks. Second, working from top to bottom left to right, the DCT is applied to each block. Third, each block is compressed through quantization. Fourth, the array of compressed blocks that make up the image is stored in a greatly reduced amount of space. Finally if desired, the image is reconstructed through decompression, a process using IDCT (inverse discrete cosine transform).

• Proceedings of the Korean Information Science Society Conference
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• 2010.06c
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• pp.62-65
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• 2010

Image annotations allow users to access a large image database with textual queries. But since the surrounding text of Web images is generally noisy. an efficient image annotation and retrieval system is highly desired. which requires effective image search techniques. Data mining techniques can be adopted to de-noise and figure out salient terms or phrases from the search results. Clustering algorithms make it possible to represent visual features of images with finite symbols. Annotationbased image search engines can obtains thousands of images for a given query; but their results also consist of visually noise. In this paper. we present a new algorithm Double-Circles that allows a user to remove noise results and characterize more precise representative annotations. We demonstrate our approach on images collected from Flickr image search. Experiments conducted on real Web images show the effectiveness and efficiency of the proposed model.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.1
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• pp.59-64
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• 2023

With the recent development of IT technology, medical image processing technology is also widely used in the dental field, and the treatment effect is enhanced by using 3D data such as CT. In this paper, open source libraries such as ITK and VTK are introduced to develop dental medical image processing software, and how to use them to develop dental medical image processing software centering on 3D CBCT. In ITK, basic algorithms for medical image processing are implemented, so the image processing pipeline can be quickly implemented, and the desired algorithm can be easily implemented as a filter by the developer. The developed algorithm is linked with VTK to implement the visualization function. The developed SW can be used for dental diagnosis and treatment that overcomes the limitations of 2D images..

• Journal of applied mathematics & informatics
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• v.26 no.5_6
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• pp.1149-1159
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• 2008

Blind source extraction (BSE) is a special class of blind source separation (BSS) methods, which only extracts one or a subset of the sources at a time. Based on the time delay of the desired signal, a simple but important extraction algorithm (simplified " BC algorithm")was presented by Barros and Cichocki. However, the performance of this method is not satisfying in some cases for which it only carries out the constrained minimization of the mean squared error. To overcome these drawbacks, ICA with reference (ICA-R) based approach, which considers the higher-order statistics of sources, is added as the second stage for further source extraction. Specifically, BC algorithm is exploited to roughly extract the desired signal. Then the extracted signal in the first stage, as the reference signal of ICA-R method, is further used to extract the desired sources as cleanly as possible. Simulations on synthetic data and real-world data show its validity and usefulness.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.564-575
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• 2015

A self-administered survey was conducted in dental hygiene students at colleges or universities in Daegu and North Gyeongsang Province to provide basic data necessary to suggest standards for the direction of career for dental hygiene students and construct desirable image of dental hygienists. The data were collected from February to May 2013; with the exception of 46 questionnaires containing insincere responses, 1,679 were finally analyzed using SPSS/Win 18.0, drawing the following conclusion: The freshmen showed higher levels of regret for selection and enrollment recommendation than the sophomores, juniors, or seniors and the sophomores, juniors, and seniors showed higher levels of willingness to change courses than the freshmen; thus, those in lower grades showed higher environment satisfaction. As for desired career, regardless of grades, they showed higher preference for being employed as a dental hygienist; as for desired paths to get a job, the freshmen were more likely to get professors' recommendations and the sophomores, juniors, and seniors showed higher preference for open recruitment. They showed higher preference for getting a job in a large city because of greater possibility of improvement. As for the desired period of employment, regardless of grades, they showed higher preference for employment before getting married and for reemployment after their children grew up; as for desired workplace, the freshmen showed higher preference for a dental clinic in a hospital, whereas the sophomores, juniors, and seniors showed higher preference for a dental hospital. As for the differences in image of dental hygienists by grades, the freshmen and sophomores showed higher levels of attitudes than the juniors; the freshmen and sophomores showed higher levels of beliefs than the juniors or seniors; and the seniors showed higher levels of values than the freshmen, sophomores, or juniors, and the sophomores and juniors showed higher levels of values than the freshmen; thus, students in lower grades showed higher levels of attitudes and beliefs and those in higher grades showed higher levels of values. Such factors of enrollment satisfaction as willingness to change courses and persuasion to make enrollment had significant effects on image of dental hygienists. Dental hygiene students need to make efforts to establish a job identity and get desirable image of dental hygienists and to make constant efforts to promote more accurate and positive image of dental hygienists through systematic and positive public relations.

• Journal of Power System Engineering
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• v.15 no.1
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• pp.18-23
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• 2011

Image processing has provided powerful techniques to extract from the acoustic signals the desired information on evaluation for leakage existence, leakage rate, and searching for leakage location, etc. The imagery NDE data available can add additional and significant dimension in nondestructive evaluation(NDE) information and thus for exploiting in applications. To extract such information the use of advanced image processing techniques is much needed. In recent years, there has been much increased use of acoustic signal image processing techniques in acoustic NDE. This approach will increase the efficiency of inspection procedures and reduce inspection time. In this paper we are concerned only with This paper is concerned mainly with the use of advanced image processing techniques in valve leakage detection and advanced image restoration and enhancement methods, which attempt to evaluate promptly by a visualization method the acoustic sources while detecting the valve leakage.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.115-118
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• 2004

Images with high resolution are desired and often required in many visual applications. When resolution can not be improved by replacing sensors, either because of cost or hardware physical limits, super resolution image reconstruction method is what can be resorted to. Super resolution image reconstruction method refers to image processing algorithms that produce high quality and high resolution images from a set of low quality and low resolution images. The method is proved to be useful in many practical cases where multiple frames of the same scene can be obtained, including satellite imaging, video surveillance, video enhancement and restoration, digital mosaicking, and medical imaging. The method can be either the frequency domain approach or the spatial domain approach. Much of the earlier works concentrated on the frequency domain formulation, but as more general degradation models were considered, later researches had been almost exclusively on spatial domain formulations. The method in spatial domains has three stages: i) motion estimate or image registration, ii) interpolation onto high resolution grid and iii) deblurring process. The super resolution grid construction in the second stage was discussed in this paper. We applied the Maximum A­Posteriori(MAP) reconstruction method that is one of the major methods in the super resolution grid construction. Based on this method, we reconstructed high resolution images from a set of low resolution images and compared the results with those from other known interpolation methods.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.5
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• pp.373-381
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• 2017

DBS(Doppler Beam Sharpening) algorithm is a way to improve azimuth resolution performance in radar. Since DBS image includes the is information about the search area of radar, various clutter components exist besides the target to be detected. To detect and track the desired target in a DBS image, it must be able to identify a target and the clutter components. In this paper, we describe how to use image size and terrain information(DTED) to identify the target in a DBS image. By using morphological filter and chain code, it acquires image size and excludes the clutter components. By matching with DTED, we determine target.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.4
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• pp.633-654
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• 2010

High quality camera images, with good contrast and intensity, are needed to obtain the desired information. Images need to be enhanced when they are dark or bright. The histogram equalization technique, which flattens the density distribution of an image, has been widely used to enhance image contrast due to its effectiveness and simplicity. This technique, however, cannot be used to enhance images that are either too dark or too bright. In addition, it is difficult to perform histogram equalization in real-time using a general-purpose computer. This paper proposes a histogram equalization technique with AGC (Automatic Gain Control) to extend the image enhancement range. It is designed using VHDL (VHSIC Hardware Description Language) to enhance images in real-time. The system is implemented with an FPGA (Field Programmable Gate Array). An image processing system with this FPGA is implemented. The performance of this image processing system is measured.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.1
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• pp.13-19
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• 2002

In a different way of satellite image or aerial photo, the image acquired by terrestrial photogrammetry has to go through complicated management according to the desired precision and analysis range. In this study, digital surface model and ortho image for cultural asset, terrestrial structures, were made by reflectorless total station in order to increase the application of single photo, and that was analyzed and compared with the method using stereo image. Single photo is expected to be utilized as the measuring method for drawing cultural assets or examining the stability of slope in which high precision doesn't need by performing the various geometric and visual analysis using ortho image made by excluding the difficulties of acquisition and plotting of stereo image.