다중 노출 입력의 피쳐 분해를 통한 하이 다이나믹 레인지 영상 생성 방법

학위논문(석사) -- 서울대학교대학원 : 공과대학 협동과정 인공지능전공, 2022. 8. 조남익.Multi-exposure high dynamic range (HDR) imaging aims to generate an HDR image from multiple differently exposed low dynamic range (LDR) images. Multi-exposure HDR imaging is a challenging task due to two major problems. One is misalignments among the input LDR images, which can cause ghosting artifacts on result HDR, and the other is missing information on LDR images due to under-/over-exposed region. Although previous methods tried to align input LDR images with traditional methods(e.g., homography, optical flow), they still suffer undesired artifacts on the result HDR image due to estimation errors that occurred in aligning step. In this dissertation, disentangled feature-guided HDR network (DFGNet) is proposed to alleviate the above-stated problems. Specifically, exposure features and spatial features are first extracted from input LDR images, and they are disentangled from each other. Then, these features are processed through the proposed DFG modules, which produce a high-quality HDR image. The proposed DFGNet shows outstanding performance compared to previous methods, achieving the PSNR-ℓ of 41.89dB and the PSNR-μ of 44.19dB.다중 노출(Multiple-exposure) 하이 다이나믹 레인지(High Dynamic Range, HDR) 이미징은 각각 다른 노출 정도로 촬영된 다수의 로우 다이나믹 레인지(Low Dynamic Range, LDR) 이미지를 사용하여 하나의 HDR 이미지를 생성하는 것을 목표로 한다. 다중 노출 HDR 이미징은 두 가지 주요 문제점 때문에 어려움이 있는데, 하나는 입력 LDR 이미지들이 정렬되지 않아 결과 HDR 이미지에서 고스트 아티팩트(Ghosting Artifact)가 발생할 수 있다는 점과, 또 다른 하나는 LDR 이미지들의 과소노출(Under-exposure) 및 과다노출(Over-exposure) 된 영역에서 정보 손실이 발생한다는 점이다. 과거의 방법들이 고전적인 이미지 정렬 방법들(e.g., homography, optical flow)을 사용하여 입력 LDR 이미지들을 전처리 과정에서 정렬하 여 병합하는 시도를 했지만, 이 과정에서 발생하는 추정 오류로 인해 이후 단계에 악영항을 미침으로써 발생하는 여러가지 부적절한 아티팩트들이 결과 HDR 이미지에서 나타나고 있다. 본 심사에서는 피쳐 분해를 응용한 HDR 네트워크를 제안하여, 언급된 문제들을 경감하고자 한다. 구체적으로, 먼저 LDR 이미지들을 노출 피쳐와 공간 피쳐로 분해하고, 분해된 피쳐를 HDR 네트워크에서 활용함으로써 고품질의 HDR 이미지 를 생성할 수 있도록 한다. 제안한 네트워크는 성능 지표인 PSNR-ℓ과 PSNR-μ에서 각각 41.89dB, 44.19dB의 성능을 달성함으로써, 기존 방법들보다 우수함을 입증한다.1 Introduction 1 2 Related Works 4 2.1 Single-frame HDR imaging 4 2.2 Multi-frame HDR imaging with dynamic scenes 6 3 Proposed Method 10 3.1 Disentangle Network for Feature Extraction 10 3.2 Disentangle Features Guided Network 16 4 Experimental Results 22 4.1 Implementation and Details 22 4.2 Comparison with State-of-the-art Methods 22 5 Ablation Study 30 5.1 Impact of Proposed Modules 30 6 Conclusion 32 Abstract (In Korean) 39석

In vitro susceptibilities and synergistic action of amphotericin B, 5-fluorocytosine and clotrimazole on candida albicans isolated from

치의학과/석사[한글] 구강내 상주하는 효모양 진균중 Candida species의 분포와 아울러 이들의 수종 항진균제에 대한 최저 발육억제 농도를 측정함과 동시에 이들 중 Candida albicans로 동정된 균주들에 대한 항균력을 측정하여 복합처리에 따른 항균력 상승여부를 규명함으로써 Candida증 치료에 기여할 목적으로 본 실험을 시행하여 다음과 같은 결론을 얻었다. 1. 본 실험에 사용된 시료로서는 1984년 3월부터 8월까지 연세대학교 원주의대 부속병원 치과에 내원한 환자 185명으로부터 채취한 구강도말 가검물을 사용하였으며 이로부터 분리된 진균은 120예로서 64.8%이었고 이중 102예가 Candida species이었다. 2. Candida species로 동정된 102예 중 Candida albicans가 79예(77.4%)로서 가장 많았으며 다음 Candida parapsilosis가 9예(8.8%), Candida tropicalis가 7예(6.8%)등의 순이었다. 3. 항진균제의 Candida albicans에 대한 최저 발육억제 농도는 amphotericin B가 1㎖당 0.2∼0.4mcg, clotrimazole이 1.6∼25.0mcg, 5-fluorocytosine은 12.5∼〉100.0mcg이었다. 4. Candida albicans에 대한 항진균제의 복합사용에 따른 상승효과는 amphotericin B와 5-fluorocytosine을 복합처리한 경우나 5-fluorocytosine과 clotrimazole을 복합처리한 경우 모두 분별 억제 농도(F.I.C.) 지수가 0.75보다 작아 상승효과를 나타내고 있었다. 5. 항진균제 복합처리에 의한 Candida albicans의 사멸곡선의 변화는 약제처리후 24시간부터 급속한 균의 사멸현상을 나타내었다. [영문] This is the study of antifungal activity of amphotericin B, 5-fluorocytosine and clotrimazole which are known to be antifungal agents against Candida albicans isolated from oral cavity. 1) The specimens used in this study were oral smears of 185 patients who visited dental clinic, from March 1984 to August 1984. From those 185 smears fungi were isolated in 120 cases from which 102 cases were identified to be Candida species. 2) Among 102 cases identified to be Candida species, Candida albicans were 79 cases(77.4%) which was greatest in number and the next was C. parapsilosis as 9 cases(8.8%) and C. tropicalis were founded in 7 cases(6.8%). 3) The test of antifungal activity of each antifungal agents against C. albicans showed that M.I.C. of amphotericin B was lowest and the next was clotrimazole and the highest was 5-fluorocytosine. The concentration of each agents was 0.2-9,4mcg, 1.6-25.0mcg and 12.5-〉100.0mcg. 4) The result of using two agents in combination was that in all 20 strains of C. albicans F.I.C. index was lower than 0.75 in both cases of combination of amphotericin B and 5-fluorocytosine, 5-fluorocytosine and clotrimazole which showed synergistic action. 5) The changes of killing curve in case of using t6wo antifungal agents in combination showed that killing activity became greater 24 hours after the used of agents.restrictio

GenerIron Atom

Docto

Kinetic Studies on the Low-lying Excited States of Gallium Atom

Maste

Lithospermic acid B ameliorates the development of diabetic nephropathy in OLETF rats

Lithospermic acid B (LAB), an active component isolated from Salvia miltiorrhizae, has been reported to have renoprotective effects in type 1 diabetic animal models. In the present study we investigated the effects of LAB on the prevention of diabetic nephropathy in type 2 diabetic Otsuka Long-Evans-Tokushima Fatty (OLETF) rats. LAB (20 mg/kg) was given orally once daily to 10-week-old male OLETF rats for 28 weeks. Treatment of OLETF rats with LAB had little effects on body weight and blood glucose levels. Treatment with LAB resulted in significant reduction in blood pressure. LAB markedly attenuated albuminuria and significantly lowered levels of lipid peroxidation, monocyte chemoattractant protein-1 (MCP-1), and transforming growth factor-beta (TGF-beta1) expression in renal tissues of OLETF rats. In addition, LAB inhibited the progression of glomerular hypertrophy, mesangial expansion, and expansion of the extracellular matrix in the renal cortex. Collectively, these results suggest that LAB has beneficial effects on the diabetic nephropathy in OLETF rats by decreasing blood pressure, oxidative stress, and MCP-1 expression. Our results suggest that LAB might be a new therapeutic agent for the prevention of nephropathy in type 2 diabetesope