저속촬영 기반의 초고화질 다면 영상 구현

문대혁 한국디지털콘텐츠학회 2019 한국디지털콘텐츠학회논문지 Vol.20 No.8

다양한 실감 영상 중 Screen X와 같은 다면영상은 와이드 영상의 한계를 넘어 3면 이상으로 구성된 화면을 통해 관객들에게 특별한 장치 없이 스토리를 전달하는 실감영상으로 색다른 몰입 감을 제공하고 있다. 그러나 이러한 다면영상은 화면 왜곡 현상, 스티칭 작업의 한계, 복잡한 시스템 환경 등으로 많은 영상 제작자들이 접근하기 어려운 제작 방법 중 하나이다. 이번 연구는 DSLR카메라를 이용한 타임랩스 영상을 Screen X와 같은 다면 영상 시스템에서 상영 가능한 가로 11,520 픽셀과 세로 2,160픽셀의 화면 종횡비가 5.3:1의 초고화질 3면 영상 콘텐츠 제작을 위한 화면 구성 및 제작 가이드라인을 제안하고자 한다. 이번 연구를 통해 Screen X와 같은 다면영상시스템이 대중화된 매체로 자리 잡아 관객들에게 다른 차원의 실감영상 감상을 몰입하게 만들 것이다. Multifaceted images such as Screen X among various real feeling images provide immersion with real feeling images that convey stories without special devices to audiences through three sided screens beyond the limit of wide screen. However, these multifaceted images are one of the difficult producing methods that video producers can't easily access due to screen distortion phenomena, limit of stitching work and complicated system environment. This study is intended to present the guidelines of screen organization and producing to make three sided image contents with 11,520 pixel width, 2,160 length and 5.3:1 screen aspect ratio ultra high definition that time lapse videos with the use of DSLR cameras can be played in multifaceted images like Screen X. Based on the results acquired through this research, it was expected that multi-image systems such as Screen X can be recognized as a popular medium capable of providing audiences with a sense of immersion in the process of appreciating different-dimensional realistic images.

부갑상선기능항진증 환자에서 Tc-99m MIBI 부갑상선 신티그라피를 이용한 병소 국소화

문대혁,류진숙,이희경,김재승,홍승모,홍석준,신중우,공경엽 대한핵의학회 1999 핵의학 분자영상 Vol.33 No.2

Purpose: This study was performed to evaluate the diagnostic usefulness of double-phase Tc-99m MIBI parathyroidism scintigraphy with single photon emission computed tomography (SPECT) in patients with hyperparathyroidism. We also evaluated the relationship between Tc-99m MIBI uptake and oxyphil cell contents in parathyroid glands. Materials and Methods: The subjects were 28 parathyroid glands of 10 patients who underwent Tc-99m MIBI parathyroid scintigraphy and parathyroidectomy for clinically suspected hyperparathyroidism. Early and delayed pinhole images were obtained at 15 minutes and 2 hours after injection of Tc-99m MIBI, and SPECT images were followed. The weight and oxyphil cell contents of parathyroid of tissue were obtained from pathologic specimen, and the scintigraphic findings were compared with histopathology. Results: In surgical histopathology, 6 parathyroid adenomas and 9 parathyroid hyperplasias were confirmed. The sensitivity, specificity, and positive predictive value of early and delayed images were 46.7% (7/15), 76.9% (10/13), 70% (7/10) and 667% (10/15), 92.3% (12/13), 90.9% (10/11), respectively. SPECT image detected an additional small hyperplasia. The sensitivity, specificity, and positive predictive value of combined interpretation of early and delayed images with SPECT were 733% f11/15), 100% (13/13), 100% (11/11). The sensitivity was 100% (6/6) for aenoma, whereas that was 555% (5/9) for hyperplasia. Both adenomas and hyperplasias showed significantly increased oxyphil cell contents compared with normal parathyroid glands (p<0.0001), but the oxyphil cell content and weight were not significantly different between adenomas and hyperplasias. Conclusion: Double-phase Tc-99m MIBI parathyroid scintigraphy with SPECT is useful for lesion localization m patients with hyperparathyroidism. Although both adenoma and hyperplasia have increased oxyphil cell content, the sensitivity is high in adenoma, but low in hyperplasia.

크로마키 기법을 이용한 고해상도 디지털 사이니지 실감 영상 구현

문대혁 대한산업경영학회 2021 산업융합연구 Vol.19 No.6

디지털 사이니지와 다면 영상 시스템은 강한 몰입감으로 스토리와 정보를 전달하는 제4의 미디어로 사용되 고 있다. 대형 디지털 사이니지에서 상영되는 콘텐츠는 주로 실사 영상보다는 컴퓨터 그래픽을 이용한 영상으로 제작되고 있다. 그 이유 중 하나는 콘텐츠 제작을 위해 촬영된 영상을 사용하려면 제작범위가 극히 제한적이고 고해 상도 실사 촬영의 한계로 크고 넓게 구성된 디지털 사이니지 화면에서 고화질 재현에 무리가 많기 때문이다. 반면 영화 상영관 중앙에 있는 스크린과 좌, 우측 벽면을 스크린으로 활용한 Screen X와 Escape는 디지털 시네마용 카메라 3대로 실사 촬영하여 스티칭 작업 후 다면 영상 시스템을 갖춘 극장에서 실감 영상으로 상영되는데 관객들 에게 많은 실감 체험을 주고 있다. 이번 연구는 Screen X의 다면 영상 촬영 제작기술과 크로마키 기법을 이용하여 고해상도로 촬영된 영상을 디지털 사이니지에서 화질 열화 없이 상영할 수 있을 것이다. Digital Signage and multi-view image system are used as the 4th media to deliver stories and information due to their strong immersion. A content image displayed on large Digital Signage is produced with the use of computer graphics, rather than reality image. That is because the images shot for content making have an extremely limited range of production and their limitation to high resolution, and thereby have difficulty being displayed in a large and wide Digital Signage screen. In case of Screen X and Escape that employ the left and right walls of in the center a movie theater as a screen, images are shot with three cameras for Digital Cinema, and are screened in a cinema with multi-view image system after stitching work is applied. Such realistic images help viewers experience real-life content. This research will be able to display high-resolution images on Digital Signage without quality degradation by using the multi-view image making technique of Screen X and Chroma key technique are showed the high-resolution Digital Signage content making method.

서로 다른 이중에너지 방사선흡수기계 기종 (Hologic QDR 4500-A 와 Lunar EXPERT-XL)간의 골밀도 교차 보정

문대혁,김기수,이희경,김재승,신중우,조진만,김상욱 대한핵의학회 1999 핵의학 분자영상 Vol.33 No.3

Purpose: A cross-calibration equation is needed to compare bone mineral density measured by different dual X-ray absoptiometry systems. We performed this study to establish appropriate cross-calibration equations between two different dual X-ray absorptiometry systems. Materials and Methods: Bone mineral density of anterior-posterior lumbar spine (L2-4 level) and femoral neck were measured in 109 women (55±11yr) using two different dual X-ray absorptiometry systems (Lunar EXPERT-XL) and Hologic QDR 4500-A). Bone mineral density values measured by two systems, including area, bone mass content, bone mineral density and percentile of young normals were compared and cross-calibration equations between two systems derived. Results: The bone mineral density values of 109 women measured by Lunar system were 0.958±0.17 g/cm2 at L2-4 and 0.768±0.131 g/cm2 at femur neck, which were significantly higher (13±6% at L2-4 and 19±7% at femur neck, p<0.001) than those (0.851±0.144 g/cm2 at L2-4 and 0.649±0.108 g/cm2 a neck) by Hologic system. Bone mineral content and percentile of young normals measured by Lunar system were also significantly higher than those by Hologic system (p<0.001), whereas there was no difference in area (p>0.05). There was a high correlation between bone mineral density values of L2-4 and femoral neck obtained with both dual X-ray absortiometry systems (r=0.96 and 0.95, respectively). Cross-calibration equations relating the bone mineral density were Lunar=1.1287×Hologic-0.0027 for L2-4 and Lunar=l.1556×Hologic+0.0l82 for femoral neck. Conclusion: We obtained cross-calibration equations of bone mineral density between Lunar EXPERT-XL and Hologic QDR 4500-A. These equations can be useful in comparing bone mineral density obtained by different dual X-ray absorptiometry systems.

악성 폐종양환자에서 99mTc-MAA 를 이용한 폐주사

문대혁,김소연,이명철,조보연,김노경,고창순,한용철,이문호,김주현 대한핵의학회 1985 핵의학 분자영상 Vol.19 No.1

정상인 및 갑상선질환 환자에서 thyroxine 투여에 따른 TSH 분비능 억제에 관한 연구

문대혁,이명식,오연상,박성기,조보연,고창순 대한핵의학회 1985 핵의학 분자영상 Vol.19 No.1

Usefulness of T1-201 Triple head SPECT imaging in detection of coronary disease

문대혁 대한핵의학회 1994 핵의학 분자영상 Vol.28 No.2

초록집 : 99mTc - RBC SPECT를 이용한 간혈관종의 진단

문대혁,조시만,이명혜,김해련,정영화,이영상,민영일,신성해,홍기석 대한핵의학회 1991 핵의학 분자영상 Vol.25 No.1

The value of (99m)^Tc-RBC scintigraphy and SPECT in the diagnosis of hepatic hemangioma was evaluated in 27 patients with 38 hemangiomas and 13 patients with 15 nonhemangiomas. Twenty four (63.2%) of 38 hemangiomas were detected by planar delayed RBC imaging, whereas 30 (78.9%) hemangiomas were detected by the delayed RBC SPECT. Increase in sensitivity was noted in nodules less than 2 cm in diameter. The smallest hemangioma shown by delayed RBC SPECT was 0.9 cm in diameter. All of nonhemangiomatous lesions show normal or decreased activity in delayed blood pool images. We concluded that (99m)^Tc-RBC SPECT is an accurate method for the detection of hepatic hemangioma and is more sensitive than planar imaging in depicting small lesions.

한국 정상인에서 연령에 따른 뇌혈류분포와 혈류예비능의 변화 : Tc-99m HMPAO SPECT 에 의한 연구

문대혁,이희경,송호천,이재태,범희승,손혜경,정환정,민정준,김지열 대한핵의학회 1999 핵의학 분자영상 Vol.33 No.3

Purpose: The aim of this study was to evaluate the normal values of regional cerebral blood flow (rCBF) and cerebrovascular reserve (CVR) in normal children to aged volunteers using Tc-99m HMPAO. Materials and Methods: Thirty four right-handed normal volunteers (20 males, 14 females, mean age 40.3±24.9 years, range 4 to 82 years) were underwent rest/acetazolamide (ACZ) brain SPECT using Tc-99m HMPAO and the sequential injection and subtraction method. rCBF was estimated on the basis of a semiquantitative approach by means of right/left ratio, region/cerebellum and region to whole brain ratios in frontal, parietal, temporal, and occipital lobes, basal ganglia, thalami, and cerebellum. CVR was measured by means of % perfusion increase calculated as % mean count change compared to rest rCBF in each regions. Results: Mean values of right to left ratios range from 1.004 to 1.018. rCBF was highest in cerebellum and lowest in basal ganglia and thalami. Frontal and temporal rCBF decreased while occipital and thalami rCBF increased according to age. No sexual difference of rCBF was noted. Mean CVR was 29.9±12.9%. Mean CVR significantly increased to late teens, and declined thereafter. After 6th decade, CVR in both frontal lobes, left parietal lobe and right basal ganglia decreased significantly with advancing age. There was no sexual difference of CVR. Conclusion: Quantitative assessment of CVR was possible by ACZ Tc-99m HMPAO brain SPECT. It revealed that rCBF and CVR changed according to age in normal Korean volunteers. There was no sexual difference.

영화관의 기술변천에 대한 연구

문대혁 남서울대학교 2017 남서울대학교 논문집 Vol.23 No.-