• 대한방사선기술학회지:방사선기술과학
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• 제44권1호
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• pp.31-37
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• 2021

This study aim of quantitative assessment of Noise Power Spectrum(NPS) and image characteristics of by acquired the optimal image for noise characteristics and quality assurance by using magnetic resonance imaging(MRI). MRI device was (MAGNETOM Vida 3.0T MRI; Siemense healthcare system; Germany) used and the head/neck shim MR receive coil were 20 channels coil and a diameter 200 mm hemisphere phantom. Frequency signal could be acquired the K-space trajectory image and white image for NPS. The T2 image highest quantitatively value for NPS finding of showed the best value of 0.026 based on the T2 frequency of 1.0 mm-1. The NPS acquired of showed that the T1 CE turbo image was 0.077, the T1 CE Conca2 turbo image was 0.056, T1 turbo image was 0.061, and the T1 Conca2 turbo image was 0.066. The assessment of NPS image characteristics of this study were to that could be used efficiently of the MRI and to present the quantitative evaluation methods and image noise characteristics of 3.0T MRI.

• 대한방사선기술학회지:방사선기술과학
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• 제44권4호
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• pp.327-333
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• 2021

Magnetic resonance imaging(MRI) uses strong magnetic field to image the cross-section of human body and has excellent image quality with no risk of radiation exposure. Because of above-mentioned advantages, MRI has been widely used in clinical fields. However, the noise generated in MRI degrades the quality of medical images and has a negative effect on quick and accurate diagnosis. In particular, examining a object with a detailed structure such as brain, image quality degradation becomes a problem for diagnosis. Therefore, in this study, we acquired T2 weighted 3D data of multiple sclerosis disease using BrainWeb simulation program, and used quantitative evaluation factors to find appropriate slice thickness among 1, 3, 5, and 7 mm. Coefficient of variation and contrast to noise ratio were calculated to evaluate the noise level, and root mean square error and peak signal to noise ratio were used to evaluate the similarity with the reference image. As a result, the noise level decreased as the slice thickness increased, while the similarity decreased after 5 mm. In conclusion, as the slice thickness increases, the noise is reduced and the image quality is improved. However, since the edge signal is lost due to overlapped signal, it is considered that selecting appropriate slice thickness is necessary.

• 대한방사선기술학회지:방사선기술과학
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• 제45권6호
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• pp.483-489
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• 2022

This study proposes a new skull lateral examination, and provides an improved examination environment for patients and radiologists. The study was divided into three groups. One group was divided into the SID (source to image receptor distance) 110 ㎝ and 180 ㎝ in the skull lateral posture, the other group The other group was divided into an position in contact with the detector and an position without contact with the detector, and the other group was divided into male and female groups, considering that the difference in shoulder width between adult males and females would affect the dose and image quality. For dose evaluation, the ESD (entrance surface dose) was measured at the EAM (external auditory meatus), and the conditions were applied equally at 70 ㎸p, 200 ㎃, and 10 ㎃s. For image quality evaluation, SNR (signal to noise ratio) and CNR (contrast to noise ratio) were measured in frontal sinus, EAM, and sella turcica. As a result of ESD comparison, when sid 110 ㎝ to sid 180 ㎝ was changed among the three groups, ESD values decreased the most to 729.18±4.62 μ㏉ and 224.18±0.74 μ㏉ at 180 ㎝ (p<0.01). The values of SNR and CNR were statistically significant (p<0.01), but there was no qualitative difference. This shows that when the SID is 180 ㎝, it is possible to reduce the dose without lowering the image quality. So, It is suggested that the SID 180 ㎝ is used without contacting the detector when examining the skull lateral.

• 한국콘텐츠학회논문지
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• 제10권6호
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• pp.329-335
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• 2010

디지털 방사선시스템에서의 의료영상 획득의 방법은 X선을 조사하고, 반도체 디텍터(Detector)를 이용하여 직접 및 간접으로 변환하여 기존 업체마다 여러 가지 알고리즘을 적용하여 적절한 이미지 프로세싱을 거쳐서 임상의 적정한 영상을 획득한다. 방사선과에서 적절한 의료 영상 형성을 위하여 적용하는 이미지 프로세싱 파라미터(Image Processing Parameters)는 Edge, Frequency, Contrast, Latitude, LUT, Noise 등의 영상 증강의 과정은 기술력 및 업체 알고리즘에 따라 다르게 적용되고 있다. 따라서 본 논문에서는 디지털 방사선 환경에서의 최종의 임상 영상을 위한 이미지 증강의 파라미터들의 적정 세팅 값의 기준을 제시하고자 한다. 그리고 각 병원들의 의료 영상을 바탕으로 이미지 프로세싱 파라미터들을 변화하여 각 파라미터들의 세부적인 기준 세팅값을 연구하며, 실제적인 파라미터 변화에 대한 적합한 의료 영상을 디지털방사선시스템의 영상 평가 방법을 도식화하여 결과를 제시하고, 향후 임상에서 적응 및 활용 가능한 객관적인 영상 파라미터에 대한 특성 평가의 응용을 정립하고자 한다. 또한 다양한 표본 병원의 디지털 방사선 환경에서 적정 파라미터 값들을 조사하여 임상에서 영상의 화질에 미치는 영향으로 특성 평가의 객관적인 기준의 변조전달함수(MTF)의 공간해상력을 제시하고 한다.

• 품질경영학회지
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• 제49권1호
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• pp.47-60
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• 2021

Purpose: This study proposes methods and procedures for evaluating imaging security systems quality of cabinet x-ray screening system to enhance performance certification technology. Also, conducted a comparative analysis of the literature of test-kit for imaging security quality evaluation. Methods: Comparative analysis of the test-kits and related documents for image quality assessment of cabinet x-ray screening equipment. This allows assessment items were selected and the methods for each assessment item were proposed. In addition, the configuration method of the assessment team was established by applying the technology readiness assessment(TRA). Results: Four of the assessment items were selected when estimate image quality by a comparative analysis of literature. For each assessment item, the evaluation method and minimum level of availability were determined. Finally, this paper proposes an imaging quality assessment of cabinet X-ray imaging security systems. Conclusion: Development of imaging security systems evaluation procedures for cabinet X-ray screening systems can be help improve performance certification of aviation security equipment.

• 한국방사선학회논문지
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• 제15권3호
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• pp.301-306
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• 2021

전산화단층촬영장치 (Computed tomography, CT)의 의료 방사선량을 낮추기 위한 방법으로 주석필터의 사용을 통해 직접적으로 환자의 선량을 낮추는 방법이 있다. 그러나 주석필터의 사용으로 바뀐 X선 스펙트럼으로 인해 기존의 영상과 다른 인상의 영상으로 나타나기 때문에 질병 진단에 영향을 줄 수 있다. 따라서 본 연구에서는 흉부 저선량 CT에서 주석필터의 적용 및 high pitch에 따른 영상평가를 진행함으로써 주석필터 사용 시 영상의 변화 양상을 살펴보았다. 본 연구에서는 비교를 위해 총 3개의 그룹으로 나누어 영상을 획득하였다. Group 1은 주석필터를 사용하지 않았으며, 기존에 사용하던 pitch인 0.8의 영상을 획득하였다. Group 2는 주석필터를 사용하였고, pitch는 0.8이며 Group 3은 주석필터를 사용하였으며 pitch는 2.5이다. 영상의 화질을 비교하기 위해 no-reference 기반으로 사용되는 블라인드 품질 평가 인자 중 natural image quality evaluator (NIQE)와 blind/referenceless image spatial quality evaluator (BRISQUE)를 사용하였다. 그 결과 NIQE 수치는 Group 1, Group 3, Group 2 의 순서대로 낮게 나타났다. BRISQUE 수치는 Group 3, Group 2, Group 1 의 순서대로 낮게 나타났다. 이를 통해 흉부 저선량 CT에서 주석필터 및 high pitch 기술의 영상의 우수성을 확인함으로써 특히 호흡 조절이 어려운 흉부 저선량 CT 환자에 있어서 더 정확한 영상에 대한 기대감을 가질 수 있는 기초 자료로 활용될 수 있을 것이라 사료된다.

• Journal of Welding and Joining
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• 제19권4호
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• pp.379-383
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• 2001

Resistance spot welding has been widely used in the sheet metal joining processes because of low cost, high productivity and convenience. Recently, automobile and aerospace industries are trying to replace partly steel sheets with aluminum alloy sheets. But in the case of dissimilar materials, to apply resistance spot welding has been known to be very difficult owing to the effect of melting temperature. On this study, an effort was made to apply spot welding of dissimilar sheet metals, 2024 aluminum alloy and zinc coated steel sheet, evaluate the spot weld quality with tensile-shear strength test and nondestructive evaluation technique, C-scan image methodology. In this study results, as the current below 11 kA, melting of materials is not achieved well. Also as the current exceeds to 13.5 kA, the more spatters happen at welded zone and tensile-shear strength lowered. So, the feasibility of C-scan image technique proposed in the study is found to be suitable evaluation method for resistance spot weldability.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1228-1231
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• 2009

This paper presented an automatic system for display quality measurement by image processing. The goal is to replace human eyes for display quality evaluation by computer vision and get the objective quality review for consumer to make purchase of monitor or TV. Color, contrast, brightness, sharpness and motion blur are the main five factors to affect display quality that could be measured by supplying patterns and analyzing the corresponding images captured from webcam. The scores are calculated by image processing techniques. Linear regression model is then adopted to find the relation between human score and the measured display performance.

• 수산경영론집
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• 제44권1호
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• pp.1-14
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• 2013

The purpose of this study is examining an influence of a corporate on processed marine product's purchase intention with moderating effect of consumers' product evaluation adding processed marine product's evaluations as new variable. The hypothesis of a positive influence of processed marine product's corporate image on processed marine product's purchase intension is partially supported. Specifically, product itself, service, reliability, and communication among the factors of a processed marine product's corporate image significantly affect processed marine product's purchase intension whereas corporate social responsibility does not affect processed marine product's purchase intention. Processed marine product's evaluation also positively affects processed marine product's purchase intention. It implies that there are somewhat differences between influences of various factors of a processed marine product's corporate image on processed marine product's purchase intention but are overall influences of a processed marine product's corporate image on processed marine product's evaluation both directly and indirectly. Nowadays, consumer considers not only good quality of product but also its invisible image and value. Therefore, future studies should consider various ways to investigate a processed marine product's corporate image and processed marine product's product evaluation.

• 대한방사선기술학회지:방사선기술과학
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• 제46권3호
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• pp.207-217
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• 2023

Image noise reduction algorithm performs important functions in light microscopy. This study aims to systematically review the research trend of types and performance evaluation methods of noise reduction algorithm in light microscopic images. A systematic literature search of three databases of publications from January 1985 to May 2020 was conducted; of the 139 publications reviewed, 16 were included in this study. For each research result, the subjects were categorized into four major frameworks-1. noise reduction method, 2. imaging technique, 3. imaging type, and 4. evaluation method-and analyzed. Since 2003, related studies have been conducted and published, and the number of papers has increased over the years and begun to decrease since 2016. The most commonly used method of noise reduction algorithm for light microscopy images was wavelet-transform-based technology, which was mostly applied in basic systems. In addition, research on the real experimental image was performed more actively than on the simulation condition, with the main case being to use the comparison parameter as an evaluation method. This systematic review is expected to be extremely useful in the future method of numerically analyzing the noise reduction efficiency of light microscopy images.