• 디지털콘텐츠학회 논문지
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• 제16권1호
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• pp.113-121
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• 2015

디지털 기술을 이용한 유물의 문양표현 방법은 크게 디지털 탁본기술과 디지털 명암기술의 두 가지가 있다. 디지털 탁본기술은 유물에 새겨진 명문이나 문양을 원형의 훼손 없이 3차원으로 스캐닝하고 이를 객관적 수치로 입체화시켜 명암효과를 표현함으로써 디지털 탁본 데이터를 구축하여 육안으로 확인하기 어려운 원래의 명문이나 문양을 명확하게 나타낼 수 있는 디지털 기술을 말한다. 디지털 명암기술은 유물 표면의 유리질 피막으로 인해서 대상물의 깊이정보를 계산할 수 없는 경우 3차원으로 스캐닝하고 이를 실감이미지 맵핑기술을 응용하여 디지털 명암이미지를 생성하는 디지털 기술을 말한다. 디지털 탁본기술은 주로 토기나 기와 그리고 비석 등 음각 또는 양각으로 표현된 명문이나 문양을 표현하는데 유용하며, 디지털 명암기술은 디지털 탁본기술이 적용될 수 없는 자기나 유리 등의 유물에 효과적으로 이용될 수 있다.

• 대한디지털의료영상학회논문지
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• 제10권2호
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• pp.39-49
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• 2008

Extravasation of contrast material is a not infrequent complication of enhanced imaging studies and large volume extravasation may result in severe damage. Subcutaneous extravasation of the radiographic contrast medium is one of the complications of the contrast medium-enhanced procedures. Automated power injectors enable the contrast material to be delivered at a uniform high-flow-rate and as a nonfragmented bolus, and this is essential for many contrast material enhanced CT(computed tomography) applications. The major risk associated with the use of automated power injectors is the well known complication of contrast material extravasation at the injection site. Automated injection of CT contrast material can produce the compartment syndrome. Selection of the nonionic contrast material after careful evaluation of the intravenous administration site and monitoring of the patient during the use of a mechanical power injector may help minimize or prevent extravasation injuries. Early identification is important and conservative management is effective in most cases. Prevention of these injuries with the education of radiological technologist remains the ultimate aim.

• 품질경영학회지
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• 제44권3호
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• pp.527-540
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• 2016

Purpose: The purpose of this study was to propose contrast metric which is based on the human visual perception and thus it can be used to improve the quality of digital images in many applications. Methods: Previous literatures are surveyed, and then the proposed method is modeled based on Human Visual System(HVS) such as multiscale property of the contrast sensitivity function (CSF), contrast constancy property (suprathreshold), color channel property. Furthermore, experiments using digital images are shown to prove the effectiveness of the method. Results: The results of this study are as follows; regarding the proposed contrast measure of complex images, it was found by experiments that HVS follows relatively well compared to the previous contrast measurement. Conclusion: This study shows the effectiveness on how to measure the contrast of complex images which follows human perception better than other methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권7호
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• pp.3401-3420
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• 2018

Pixel expansion and contrast are two major performance parameters for visual cryptography scheme (VCS), which is a type of secret image sharing. Random Grid (RG) is an alternative approach to solve the pixel expansion problem. Chen and Tsao proposed the first (k, n) RG-based VCS, and then Guo et al., Wu et al., Shyu, and Yan et al. significantly improved the contrast in recent years. However, the investigations on improving the contrast of threshold RG-based VCS are not sufficient. In this paper, we develop a contrast-improved algorithm for (k, n) RG-based VCS. Theoretical analysis and experimental results demonstrate that the proposed algorithm outperformers the previous threshold algorithms with better visual quality and a higher accuracy of contrast.

• 대한디지털의료영상학회논문지
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• 제9권1호
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• pp.17-19
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• 2007

This study applies in case of operating an exam using by the contrast order or inputting an order of a contrast media the exam of Radiology Department. It is developed for helping decision making as regards a process of an exam from reading the creatinine value automatically linked with Laboratory Information System. It can be confirmed by real-time information; therefore, the creditability of the information is able to be improved. We will create the base for Patient Monitoring System with the data from the side effect of the creatinine value and allergies. Decision Support System minimize the inconvenience and the riskiness of the given contrast medium for CT tests. We would like to improve medical services by providing a standard circumstance where patients are able to run tests safely and comfortably.

• 대한디지털의료영상학회논문지
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• 제12권2호
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• pp.81-87
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• 2010

The setting parameters of ultrasound scanner give influences to change of image. Sonographers have used a Matlab program to make Low Contrast Sensitivity(LCS) value and compared original images in order to evaluate the use of the supersonic diagnosis machinery. We confirmed the change of image in Grayscale values using Photoshop program. Experiment equipment of our research used A Medison Accuvix V10, A Multi-Tissue Ultrasound Phantom(040 GSE) of CHRIS Company, A Adobe Photoshop CS4 Program, A Convex Probe, A USB memory stick, A Probe Fixation Equipment. The method used Gain, Dynamic Range(DR) of the setting parameters of ultrasound scanner and researched Gain and DR was set to 10 dB. We changed the different settings to see the changes of images using Grayscale values of a Photoshop program about tissue images of a phantom. This study evaluated DR and Gain whether it is an image controller to get the optimum contrast to produce an image to see the how effect on the images. We did not use Gateway in supersonic diagnosis machinery. We can easily open to open the files through Photoshop program before we get Digital Imaging and Communications in Medicine(DICOM) files use USB memory stick in supersonic diagnosis machinery. When we diagnosed the lesion of the patient with ultrasound, the contrast and the Gray scale value of image are very important. In this research, we determined the optimum setting parameters that provided useful information to diagnose disease and evaluated the change of improved images.

• 한국도서관정보학회지
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• 제27권
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• pp.423-456
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• 1997

As information technology has been evolving, digital library emerges as a vision of future library. Many authors on digital library describe that the problems that today's libraries face would be completely solved by using digital technology. But it is su n.0, pposed that such technology oriented papers do not take care of what the library has been and should remain. This paper is prepared to identify what core elements of library services being provided in traditional environment must be transferred to the digital library. For this purpose, firstly historical transition from traditional library to digital discussed. Secondly, library's fundamental service functions are analysed from three points of view-library as cultural and social institution, library as intellectual reality, library as a collection. And 'control zone' concept is also investigated as a new possibility of academic digital libraries. In contrast to open zone in which information is not controled at all as in internet, in control zone, information is selected and maintained by academic library community, retaining such essential library functions as selection.

• 센서학회지
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• 제13권1호
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• pp.56-65
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• 2004

In this paper, we proposed the detection algorithm of microcalcification based on region growing method with contrast and edge sharpness in digital X-ray mammographic images. We extracted the local maximum pixel and watershed regions by using watershed algorithm. Then, we used the mean slope between local maximum and neighborhood pixels to extract microcalcification candidate pixels among local maximum pixels. During increasing threshold value to grow microcalcification region, at the maximum threshold value of the contrast and edge sharpness, the microcalcification area is decided. The regions of which area of grown candidate microcalfication region is larger than that of watershed region are excluded from microcalcifications. We showed the diagnosis algorithm can be used to aid diagnostic-radiologist in the early detection breast cancer.

• 대한방사선기술학회지:방사선기술과학
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• 제44권1호
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• pp.1-8
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• 2021

The purpose of this study was to analyze the effect of automatic exposure control (AEC) control factors in digital radiography systems based on the fine contrast images using coin phantoms. The AEC control factors were targeted at the range of dominent zone, sensitivity, and density. The dominent zone was divided into cases where a single coin was used to cover the field configuration, and cases where seven coins were used to cover the field configuration. The sensitivity was classified into three stages (200, 400, 800) and the density was classified into three stages (2.5, 0, 2.5). Image quality was evaluated by signal to noise ratio (SNR) and contrast to noise ratio (CNR). Then, the automatically exposed tube current was measured. As a result, the X-ray image of seven coins obtained a result value of about 1.2 times higher for SNR and 1.9 times higher for CNR than the X-ray image for one coin. The tube current was also about 1.6 times higher. In conclusion, In AEC, the higher the field configuration and dominent zone are matched and the higher the density, the lower the sensitivity, which increases the tube current and CNR, which increases the image quality. Therefore, it is judged that the appropriate setting of the range of dominent zone, sensitivity, and density of the control, which is the AEC control factor, could improve the fine contrast of images.

• 대한디지털의료영상학회논문지
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• 제12권1호
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• pp.19-25
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• 2010

This study is mainly for the reduction of exposure dose by using a heavy elements filter(Gd) in the digital radiology. They contained heavy elements filter of Gd and X-ray beam hardening filters such as Al and Cu. According to the results of experimental evaluation, X-ray property was not changed with variety of kVp in the case of the Gd filter. The surface dose and absorption dose were increased in order of Cu and Al. The contrast of image showed the higher value in order of Cu, Al and Gd. While the use of Gd has increased the numerical value of the CR image, and grayscale has decreased noise value of the DR image.