• 대한건축학회논문집:구조계
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• 제34권10호
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• pp.11-18
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• 2018

In this study, the cross-sectional image has been acquired to evaluate the aggregate distribution affecting quality of lightweight aggregate concrete, and through the binarization method, the study is to calculate the aggregate area of upper and lower sections to develop the method to assess the aggregate distribution of concrete. The acquisition of cross-section image of concrete for the above was available from the cross-sectional photography of cleavage tension of a normal test specimen, and an easily accessible and convenient image analysis software was used for image analysis. As a result, through such image analyses, the proportion of aggregate distribution of upper and lower sections of the test specien could be calculated, and the proportion of aggregate area U/L value of the upper and lower regions of concrete cross-section was calculated, revealing that it could be used as the comprehensive index of aggregate distribution. Moreover, through such method, relatively easy image acquisition methods and analytic methods have been proposed, and this indicated that the development of modeling to assess aggregate distribution quantitatively is available. Based on these methods, it is expected that the extraction of fundamental data to reconsider the connectivity with processes in concrete will be available through quality assessment of quantitative concrete.

• 한국터널지하공간학회 논문집
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• 제26권4호
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• pp.365-384
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• 2024

인력기반의 점검보다 안전하고 효율적인 자동화 점검을 위하여 스캐닝 기술 개발이 가속화되고 있다. 컴퓨터비전 기술을 활용하여 수집된 이미지로부터 시설물 손상을 자동으로 검출하는 연구도 증가하고 있다. 이미지의 픽셀 크기, 품질 및 수량은 손상 자동 검출을 위한 딥러닝이나 이미지 처리 성능에 영향을 미칠 수 있다. 본 연구는 딥러닝기반 손상 자동 검출을 위한 이동식 터널 스캐닝 시스템의 카메라 성능과 고품질의 원시 이미지 데이터 취득을 위한 기초연구로, 이미지의 품질을 정량적으로 평가하기 위한 기법을 제안하려고 한다. 40 km/h의 이동속도 모사가 가능한 패널 장치에 테스트차트를 부착하고 국제표준 ISO 12233방법으로 실내시험을 수행하였다. 기존의 이미지 품질 평가기법들을 적용하여 실내실험에서 얻어진 이미지의 품질을 평가하였다. 카메라의 셔터스피드는 이미지에 발생하는 모션블러와 밀접한 관련이 있는 것으로 판단되었다. 이미지 품질 평가 기법 중 하나인 modulation transfer function (MTF)는 이미지 품질을 객관적으로 평가할 수 있으며, 시각적 관찰과 일치하는 것으로 판단되었다.

• Nuclear Engineering and Technology
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• 제56권6호
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• pp.2057-2062
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• 2024

Among photon counting detector (PCD)-based technologies, the K-edge subtraction (KES) method has a very high material decomposition efficiency. Yet, since the increase in noise in the X-ray image to which the KES method is applied is inevitable, research on image quality improvement is essential. Here, we modeled a block-matching and 3D filtering (BM3D) algorithm and applied it to PCD-based X-ray images with the improved KES (IKES) method. For PCD modeling, Monte Carlo simulation was used, and a phantom composed of iodine substances with different concentrations was designed. The IKES method was modeled by adding a log term to KES, and the X-ray image used for subtraction was obtained by applying the 3.0 keV range based on the K-edge region of iodine. As a result, the IKES image using the BM3D algorithm showed the lowest normalized noise power spectrum value. In addition, we confirmed that the contrast-to-noise ratio and no-reference-based evaluation results when the BM3D algorithm was applied to the IKES image were improved by 29.36 % and 20.56 %, respectively, compared to the noisy image. In conclusion, we demonstrated that the IKES imaging technique using a PCD-based detector and the BM3D algorithm fusion technique were very efficient for X-ray imaging.

• 핵의학기술
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• 제27권1호
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• pp.47-54
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• 2023

Purpose PET-CT imaging require an appropriate quality assurance system to achieve high efficiency and reliability. Quality control is essential for improving the quality of care and patient safety. Currently, there are performance evaluation methods of UN2-1994 and UN2-2001 proposed by NEMA and IEC for PET-CT image evaluation. In this study, we compare phantom images with the same experiments before and after PET-CT 3D normalization and well counter correction and evaluate the usefulness of quality control. Materials and methods Discovery 690 (General Electric Healthcare, USA) PET-CT equiptment was used to perform 3D normalization and well counter correction as recommended by GE Healthcare. Based on the recovery coefficients for the six spheres of the NEMA IEC Body Phantom recommended by the EARL. 20kBq/㎖ of ¹⁸F was injected into the sphere of the phantom and 2kBq/㎖ of ¹⁸F was injected into the body of phantom. PET-CT scan was performed with a radioacitivity ratio of 10:1. Images were reconstructed by appliying TOF+PSF+TOF, OSEM+PSF, OSEM and Gaussian filter 4.0, 4.5, 5.0, 5.5, 6.0, 6,5 mm with matrix size 128×128, slice thickness 3.75 mm, iteration 2, subset 16 conditions. The PET image was attenuation corrected using the CT images and analyzed using software program AW 4.7 (General Electric Healthcare, USA). The ROI was set to fit 6 spheres in the CT image, RC (Recovery Coefficient) was measured after fusion of PET and CT. Statistical analysis was performed wilcoxon signed rank test using R. Results Overall, after the quality control items were performed, the recovery coefficient of the phantom image increased and measured. Recovery coefficient according to the image reconstruction increased in the order TOF+PSF, TOF, OSEM+PSF, before and after quality control, RCmax increased by OSEM 0.13, OSEM+PSF 0.16, TOF 0.16, TOF+PSF 0.15 and RCmean increased by OSEM 0.09, OSEM+PSF 0.09, TOF 0.106, TOF+PSF 0.10. Both groups showed a statistically significant difference in Wilcoxon signed rank test results (P value<0.001). Conclusion PET-CT system require quality assurance to achieve high efficiency and reliability. Standardized intervals and procedures should be followed for quality control. We hope that this study will be a good opportunity to think about the importance of quality control in PET-CT

• 한국콘텐츠학회논문지
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• 제18권2호
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• pp.178-187
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• 2018

본 연구는 인물사진의 화질 평가 요소들과 선호도와의 관계를 기반으로 감상자 중심의 인물사진 선호도 측정 프로그램의 모형을 제작하여 일반인 사용자의 높은 사용률을 목적으로 하는 제조사들에게 자동화된 제품설계 및 평가 모델을 개발하는 것을 목적으로 하였다. 이미지 평가를 진행하기 위하여 이미지의 화질 측정 항목을 객관적, 주관적 항목으로 나누고, 영상처리와 통계적 방법을 통하여 정확한 평가를 진행하였다. 이미지의 화질 측정 항목은 객관적 평가항목과 주관적 평가 항목으로 나눌 수 있다. 객관적 평가 항목에는 RSC 콘트라스트, 다이내믹 레인지, 노이즈를 선정하였고, 프로그램을 통해 그 수치 값을 통계적으로 분석하여 평가하였다. 주관적 평가 항목에는 노출, 컬러 톤, 인물의 구도, 인물의 위치, 아웃포커스를 선정하였고, 영상처리 방법을 적용하여 평가하였다. 본 연구에서 개발된 프로그램을 통해 측정된 결과와 실제 육안으로 확인한 결과가 동일하게 나타남으로서 정확도가 매우 높은 것으로 확인할 수 있었다. 하지만 개발된 프로그램은 인물의 안면이 인식 되어야 평가를 진행할 수 있기 때문에, 향후 연구를 통해 이미지 내에 사람이 존재하는 모든 종류의 인물사진을 평가할 수 있는 프로그램을 개발해야할 필요가 있을 것이다.

• Korean Journal of Radiology
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• 제23권4호
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• pp.402-412
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• 2022

Objective: To evaluate the image quality and lesion detectability of lower-dose CT (LDCT) of the abdomen and pelvis obtained using a deep learning image reconstruction (DLIR) algorithm compared with those of standard-dose CT (SDCT) images. Materials and Methods: This retrospective study included 123 patients (mean age ± standard deviation, 63 ± 11 years; male:female, 70:53) who underwent contrast-enhanced abdominopelvic LDCT between May and August 2020 and had prior SDCT obtained using the same CT scanner within a year. LDCT images were reconstructed with hybrid iterative reconstruction (h-IR) and DLIR at medium and high strengths (DLIR-M and DLIR-H), while SDCT images were reconstructed with h-IR. For quantitative image quality analysis, image noise, signal-to-noise ratio, and contrast-to-noise ratio were measured in the liver, muscle, and aorta. Among the three different LDCT reconstruction algorithms, the one showing the smallest difference in quantitative parameters from those of SDCT images was selected for qualitative image quality analysis and lesion detectability evaluation. For qualitative analysis, overall image quality, image noise, image sharpness, image texture, and lesion conspicuity were graded using a 5-point scale by two radiologists. Observer performance in focal liver lesion detection was evaluated by comparing the jackknife free-response receiver operating characteristic figures-of-merit (FOM). Results: LDCT (35.1% dose reduction compared with SDCT) images obtained using DLIR-M showed similar quantitative measures to those of SDCT with h-IR images. All qualitative parameters of LDCT with DLIR-M images but image texture were similar to or significantly better than those of SDCT with h-IR images. The lesion detectability on LDCT with DLIR-M images was not significantly different from that of SDCT with h-IR images (reader-averaged FOM, 0.887 vs. 0.874, respectively; p = 0.581). Conclusion: Overall image quality and detectability of focal liver lesions is preserved in contrast-enhanced abdominopelvic LDCT obtained with DLIR-M relative to those in SDCT with h-IR.

• 생물정신의학
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• 제22권3호
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• pp.128-134
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• 2015

Objectives To examine the relationship between health-related quality of life (HRQoL) and body mass index (BMI) of obese children. Methods This cross-sectional study included 387 children. HRQoL was measured with the PedsQLTM 4.0 Generic Core Scale. BMI was classified according to the World Health Organization Asia-Pacific obesity guidelines. Psychosocial factors (body image, self-esteem, and depression/anxiety) were also measured. Data were analyzed using one-way analysis of variance, Pearson's correlation and Path analysis. Results Obese participants reported lower score for physical evaluation, self-esteem, appearance evaluation component of body image, total HRQoL score, and physical/emotional/social function components of HRQoL ; they reported higher score for depression/anxiety. In addition, results indicated that as BMI increased, appearance evaluation, total HRQoL score, and social function component of HRQoL dropped. Path analysis revealed that BMI did not directly affect HRQoL ; however, BMI directly affects body image and self-esteem, indirectly mediates depression/anxiety, and thereby impacts on an individual's HRQoL. Conclusions Body image and self-esteem, rather than BMI itself, have more influence on HRQoL. This reinforces the importance of therapeutic intervention to enhance body image and self-esteem among obese children.

• 대한방사선기술학회지:방사선기술과학
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• 제46권1호
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• pp.15-21
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• 2023

This study was purpose to assessment of the resolution characteristics by using ATS 535H Basic quality assurance (QA) phantom for ultrasound. The ultrasound equipment was used Logiq P6 (Ultrasound, GE Healthcare System, Chicago, IL, USA). And the ultrasound transducer were used Convex 4C (4~5.5 MHz), Linear 11L (10~13 MHz), Sector 3SP (3~5.5 MHz) probe. As for the noise power spectrum (NPS) comparison results by using ATS 535H Basic QA ultrasound phantom and Convex 4C, Linear 11L, Sector 3SP probe. The NPS value of the Convex 4C probe image was 0.0049, Linear 11L probe image was 0.0049, Sector 3SP probe image was 0.1422 when the frequency is 1.0 mm^-1. The modulation transfer function (MTF) comparison results by using ATS 535H Basic QA ultrasound phantom and Linear 11L probe the MTF value of the 3 cm focus image was 0.7511 and 4 cm focus image was 0.9001 when the frequency is 1.0 mm^-1. This study was presented characteristics of spatial resolution a quantitative evaluation methods by using ultrasound medical images for QA of ultrasound medical QA phantom. The quality control (QC) for equipment maintenance can be efficiently used in the clinic due to the quantitative evaluation of the NPS and MTF as the standard methods. It is meaningful in that it is applied mutatis mutandis and presented the results of physical resolution characteristics of the ultrasound medical image.

• 인포메이션 디스플레이
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• 제15권5호
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• pp.22-32
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• 2014

The current research intends to quantify the surround luminance effects on the shape of spatial luminance CSF and to propose an image quality evaluation method that is adaptive to both surround luminance and spatial frequency of a given stimulus. The proposed image quality method extends to a model called SQRI[8]. The non-linear behaviour of the HVS was taken into account by using CSF. This model can be defined as the square root integration of multiplication between display MTF and CSF. It is assumed that image quality can be determined by considering the MTF of the imaging system and the CSF of human observers. The CSF term in the original SQRI model was replaced by the surround adaptive CSF quantified in this study and it is divided by the Fourier transform of a given stimulus. A few limitations of the current work should be addressed and revised in the future study. First, more accurate model predictions can be achievable when the actual display MTF is measured and used instead of the approximation. Then, a further improvement to the model prediction accuracy can be made when chromatic adaptation of the HVS is taken into account[45-46].

• 한국컴퓨터정보학회논문지
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• 제26권2호
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• pp.213-220
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• 2021

글로벌 경제가 지속적으로 발전하는 오늘날 기업의 생산과 경영의 글로벌화가 빠른 속도로 확대되고 있으며 기업들이 성공적으로 해외진출을 하기 위하여 해외 시장에 제품을 적절한 마케팅 전략을 수립하는 것이 점차 중요해지고 있다. 소비자들이 다양한 국가로부터의 제품의 질을 평가할 경우 제품의 가격뿐만 아니라 제품의 이미지에도 많이 의존하므로 이에 본 연구에서는 제품의 가격과 이미지, 구체적으로는 국가 이미지, 브랜드 이미지, 원산지 이미지가 소비자의 제품평가 및 구매의도에 어떠한 영향을 주는지를 규명해보고자 하였다. 이를 토대로 한국 기업들에게 제품의 가격 및 이미지의 중요성과 향후 중국의 소비자들에게 보다 정확한 한국과 한국산 제품에 대한 인식을 통하여 현지진출기업의 마케팅에 도움이 되고자 한다. 본 연구에서는 중국 소비자를 대상으로 설문조사를 통해 수집된 데이터를 AMOS 통계분석 패키지를 이용하여 분석한 결과, 제품에 대한 국가 이미지 및 원산지 이미지는 제품품질에 정의 영향을, 제품의 가격과 국가 이미지는 서비스품질에 정의 영향을, 그리고 소비자의 제품에 대한 평가로 제품품질 및 서비스품질은 구매의도에 정의 영향을 미치는 것으로 나타났다.