• Korean Journal of Radiology
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• 제1권1호
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• pp.19-24
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• 2000

Objective: In order to investigate the functional brain anatomy associated with verbal and visual working memory, functional magnetic resonance imaging was performed. Materials and Methods: In ten normal right handed subjects, functional MR images were obtained using a 1.5-T MR scanner and the EPI BOLD technique. An item recognition task was used for stimulation, and during the activation period of the verbal working memory task, consonant letters were used. During the activation period of the visual working memory task, symbols or diagrams were employed instead of letters. For the post-processing of images, the SPM program was used, with the threshold of significance set at p < .001. We assessed activated brain areas during the two stimulation tasks and compared the activated regions between the two tasks. Results: The prefrontal cortex and secondary visual cortex were activated bilaterally by both verbal and visual working memory tasks, and the patterns of activated signals were similar in both tasks. The superior parietal cortex was also activated by both tasks, with lateralization to the left in the verbal task, and bilaterally without lateralization in the visual task. The inferior frontal cortex, inferior parietal cortex and temporal gyrus were activated exclusively by the verbal working memory task, predominantly in the left hemisphere. Conclusion: The prefrontal cortex is activated by two stimulation tasks, and this is related to the function of the central executive. The language areas activated by the verbal working memory task may be a function of the phonological loop. Bilateral prefrontal and superior parietal cortices activated by the visual working memory task may be related to the visual maintenance of objects, representing visual working memory.

• 한국광학회지
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• 제19권2호
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• pp.116-121
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• 2008

본 연구는 2차원 PLS(Point Light Source) 배열과 디스플레이 장치의 조합을 통하여 시역형성용 광학판이 없는 3차원 영상을 재생하는 방법에 관한 것이다. PLS를 사용하여 3차원 영상을 디스플레이 하는 경우 기존의 시차장벽(parallax barrier), 렌티큘러(lenticular), 마이크로 렌즈(microlens lens) 등의 광학판을 사용할 때 발생하는 여러 가지 광학적 문제점 등을 해소할 수 있다. PLS로 사용된 LED 광원이 가져야 할 특성을 조사하였으며 PLS 배열을 통한 입체영상 디스플레이의 시역에 대해 실험을 통하여 입증 하였다.

• 한국광학회지
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• 제23권1호
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• pp.32-35
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• 2012

본 논문에서는 집적영상방식 3D 디스플레이에서 문제점으로 지적되고 있는 입체감 증가에 따른 영상의 왜곡을 분석하고 인간 시각계의 인지한계에 근거하여 최적입체감을 구현할 수 있는 영역을 제안한다. 또한 실험결과를 통하여 이를 검증하였다.

• Journal of information and communication convergence engineering
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• 제17권1호
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• pp.60-66
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• 2019

In this paper, we propose a new free-view three-dimensional (3D) computational reconstruction of integral imaging to improve the visual quality of reconstructed 3D images when low-resolution elemental images are used. In a conventional free-view reconstruction, the visual quality of the reconstructed 3D images is insufficient to provide 3D information to applications because of the shift and sum process. In addition, its processing speed is slow. To solve these problems, our proposed method uses a pixel rearrangement technique (PERT) with locally selective elemental images. In general, PERT can reconstruct 3D images with a high visual quality at a fast processing speed. However, PERT cannot provide a free-view reconstruction. Therefore, using our proposed method, free-view reconstructed 3D images with high visual qualities can be generated when low-resolution elemental images are used. To show the feasibility of our proposed method, we applied it to optical experiments.

• International Journal of Internet, Broadcasting and Communication
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• 제14권2호
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• pp.10-16
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• 2022

As an important part of virtual production, In-camera VFX is the process of shooting actual objects and virtual three-dimensional backgrounds in real-time through computer graphics technology and display technology, and obtaining the final film. In the In-camera VFX process, there are currently only two types of medium used to undertake background imaging, LED wall and chroma key screen. Among them, the In-camera VFX based on LED wall realizes background imaging through LED display technology. Although the imaging quality is guaranteed, the high cost of LED wall increases the cost of virtual production. The In-camera VFX based on chroma key screen, the background imaging is realized by real-time keying technology. Although the price is low, due to the limitation of real-time keying technology and lighting conditions, the usability of the final picture is not high. The short-throw projection technology can compress the projection distance to within 1 meter and get a relatively large picture, which solves the problem of traditional projection technology that must leaving a certain space between screen and the projector, and its price is relatively cheap compared to the LED wall. Therefore, in the In-camera VFX process, short-throw projection technology can be tried to project backgrounds. This paper will analyze the principle of short-throw projection technology and the existing In-camera VFX solutions, and through the comparison experiments, propose a low-cost solution that uses short-throw projectors to project virtual backgrounds and realize the In-camera VFX process.

• 한국광학회:학술대회논문집
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• 한국광학회 2008년도 동계학술발표회 논문집
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• pp.181-182
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• 2008

In this paper, we propose a volumetric computational reconstruction method by use of smart pixel mapping technique in the computational integral imaging in order to overcome the problem of resolution degradation. The experimental results are presented to show the usefulness of our proposed technique.

• Smart Structures and Systems
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• 제33권1호
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• pp.55-64
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• 2024

This paper proposes a fusion imaging-based coating-defect classification method for steel structures that uses zero-shot learning. In the proposed method, a halogen lamp generates heat energy on the coating surface of a steel structure, and the resulting heat responses are measured by an infrared (IR) camera, while photos of the coating surface are captured by a charge-coupled device (CCD) camera. The measured heat responses and visual images are then analyzed using zero-shot learning to classify the coating defects, and the estimated coating defects are visualized throughout the inspection surface of the steel structure. In contrast to older approaches to coating-defect classification that relied on visual inspection and were limited to surface defects, and older artificial neural network (ANN)-based methods that required large amounts of data for training and validation, the proposed method accurately classifies both internal and external defects and can classify coating defects for unobserved classes that are not included in the training. Additionally, the proposed model easily learns about additional classifying conditions, making it simple to add classes for problems of interest and field application. Based on the results of validation via field testing, the defect-type classification performance is improved 22.7% of accuracy by fusing visual and thermal imaging compared to using only a visual dataset. Furthermore, the classification accuracy of the proposed method on a test dataset with only trained classes is validated to be 100%. With word-embedding vectors for the labels of untrained classes, the classification accuracy of the proposed method is 86.4%.

• Investigative Magnetic Resonance Imaging
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• 제21권3호
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• pp.195-198
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• 2017

Idiopathic brain herniation is a rare condition. We believe that this is the first reported case of idiopathic herniation of the lingual gyrus. The case involves a 57-year-old woman presenting with frontal headache without overt visual symptoms. Magnetic resonance imaging (MRI) revealed an idiopathic herniation of the lingual gyrus of the occipital lobe extending into the quadrigeminal cistern. No other adjacent intracranial abnormalities were observed. Although some conditions may be considered in the differential diagnosis, accurate diagnosis of idiopathic brain herniation in medical practice can prevent unnecessary additional imaging procedures and invasive open biopsy in patients with typical imaging findings.

• Investigative Magnetic Resonance Imaging
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• 제3권1호
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• pp.47-52
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• 1999

목적 : 시각자극을 이용하여 대뇌 후두엽에서 BOLD(blood oxygen level dependent)효과에 의한 기능적 자기공명영상과 양성자 자기공명분광법을 이용한 대사물질영상( metabolic i image)을 얻어 그 결과를 평가하고자 하였다. 대상 및 방법 : 24세에서 30세 사이의 8명의 남자와 2명의 여자를 포함하는 10명의 정상 성인 남녀를 대상으로 1.5T MRI에서 시각 지극을 이용하여 echo planar imaging펠스시퀀스를 사용하여 BOLD효과에 의한 영상들을 대뇌 후두엽에서 얻었다. 시각자극은 8Hz의 red flicker를 이용한 광 자극을 주였다. MR에서 얻어진 영상들을 workstation으로 전송한 뒤 자체 개발한 분석프로그램을 사용하여 상관계수방법을 이용하여 기능적 영상을 구하였다. 그리고 얻어진 영상의 활성화 부위를 선정한 뒤 양성자 자기공명 분광법을 사용하여 시각 자극에 의한 뇌 활성화시 대사물질의 변화를 분석했다. 그 후 자가공명분광영상법(magnetic resonance spectro-scopic imaging)를 실행하여 젖산(lactate)의 대사물질 영상을 얻었다. 결과 : 시각 자극에 따른 BOLD효과에 의한 뚜렷한 활성화 부위가 후두염 대뇌피질에 나타났다. 또한 이들 활성화 부위에서 자기공명분광법을 시행한 결과 휴식상태와 시각자극상태에서 NAA(N-acetyle aspartate)/Cr(creatine)이 $1.79{\pm}0.28$에서 $1.88{\pm}O.20$으로 거의 변화가 없는 것에 반해 lactate는 자극 전후 $9.48{\pm}4.38$배로 증가하였으며 이를 바탕으로 lactate에 대한 대사물질영상을 얻을 수 있었다. 결론 : 시각자극에 의한 뇌 활성화시 BOLD효과를 이용한 자기공명영상볍으로 활성화 부위를 확인할 수 있었고, 같은 부위에서 자기공명분광법을 이용하여 lactate의 증가를 확인하였다. 또한 lactate의 증가를 대사물질영상으로 표현함으로써 두 결과에 대한 상관관계 및 뇌 기능적영상에 대한 신뢰성을 높일 수 있게 되었다.

• 대한의용생체공학회:의공학회지
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• 제24권4호
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• pp.241-246
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• 2003

정상 성인을 대상으로 언어생성과제의 시각적 지시과제와 청각적 지시과제에 대한 기능적 MR영상들을 비교하고자 하였다. 6명의 정상 성인을 대상으로 자기공명영상기기를 이용하였다 시각적, 청각적 언어 지시과제는 명사의 언어를 이용하여. 휴지기. 확성기를 각각 6번 구성하였다. 뇌의 활성영역의 휴지기와 확성기의 신호변화에 따른 데이터는 MRDx 프로그램으로 처리하였고 cross correlation 방법으로 통계 처리하였다. 시각적, 청각적 지시과제의 분석방법은 lateralization index 공식으로 뇌 반구의 활성화 voxel의 총합과 좌$.$우 반구의 픽셀 수를 구하였고, 지시 과제에 대한 활성화 영역을 “Area of Activation Cells” 값에 따라 4등급으로 분류하여 비교 분석하였다. 시간적 청각적 지시과제에서 Broca, Wernicke 영역 등에서 크기는 다르지만 모두 활성화가 관찰되었다. lateralization index에서 뇌반구의 활성화 값에 차이는 시각적 지시과제에 비해 청각적 지시과제가 높은 활성화 값을 보였다. 그러므로 언어영역에 대한 뇌의 기능적 영상을 얻는데 두 방법 모두 유용하다고 생각된다.