Realistic rainbow rendering considering light attenuation due to scattering and absorption in the atmosphere

情報処理学会 グラフィクスとCAD研究会 第134回研究発表会 発表資料 ; 開催場所:NHK放送技術研究所, 東京 ; 開催日:2009年2月16-17

Realistic rainbow rendering considering light attenuation due to scattering and absorption in the atmosphere

これまで、波動光学を考慮した虹のレンダリング法が開発され、過剰虹や異なる半径の水滴による虹の表示が行われてきた。しかし、大気中の水滴分布を一様と仮定しており、大気による光の散乱・減衰も考慮されていなかった。本研究では水滴ボリュームを設定し任意の密度と半径の水滴分布を考慮できるように改良した。また、光の減衰を考慮することで太陽高度の違いによる虹の色変化を表現できるようになった。さらに、街灯のような多様なスペクトル分布を持つ点光源も扱えるように拡張した。これらを考慮することで半径に応じて変化する虹や、高度によって色が変わる虹、また、点光源によって発生する特殊な形状の虹など様々な虹をレンダリングできるようになった。A method for rendering rainbows considering the wave optics has been developed and supernumerary rainbows and rainbows generated by different radii of raindrops were rendered. However, the method assumes that the distribution of the raindrops in the atmosphere is constant, and the attenuation of light due to the scattering and absorption in the atmosphere is not taken into account. We improved the rendering method considering both density and radius of raindrops using volume representation of raindrops. Considering attenuation of light, our method can render the change of rainbow color depending on solar altitude. In addition, we extended the method to be able to use a point light source with various spectrum distributions like streetlights. Our method can render various rainbows depending on radius of raindrops, the solar altitude, and light sources

Photo-realistic rendering of rainbows based on atmospheric optical phenomena

パターン認識・メディア理解研究会(PRMU 2009):光と色の解析・表現とその応用 発表資料 ; 開催地:広島大学 ; 開催日:2009年10月22-23

水滴の分布を考慮した虹のレンダリング手法の開発

光の干渉や分散によって生じる気象現象に虹がある。これらの減少の美しさから、CG分野でその表示手法に関して研究が行われている。また気象学分野においても、シミュレーションによる気象現象の解明が待たれている。波動光学を考慮したレンダリングにより、過剰虹の表示や、水滴の大きさによって異なる虹の表示を行う手法が開発されている。しかし、この手法の問題点として空気中の水滴を2次元のスクリーン状にしか設定できず、水滴の大きさや個数が一様に分布した状態だけしかレンダリングを行えないことが挙げられる。本研究では、水滴の大きさと個数の3次元空間での分布を考慮してレンダリングを行うことができるように改良を行った

水滴の分布を考慮した虹のレンダリング手法の開発

平成19年度電気・情報関連学会中国支部連合大会発表資料。開催地:広島大学 ; 開催日:2007年10月20

Surgical resection of mixed neuroendocrine-non-neuroendocrine neoplasm in the biliary system: a report of two cases

Background Mixed neuroendocrine-non-neuroendocrine neoplasm (MINEN) is a rare disease and there is scarce literature on its diagnosis, treatment, and prognosis. We encountered two unusual cases of MINEN in the biliary tract, one in the ampulla of Vater and the other in the distal bile duct. In this report, we describe the clinical course of these two cases in detail. Case presentation Case 1: A 69-year-old woman presented with a chief complaint of epigastric pain. When endoscopic sphincterotomy and retrograde biliary drainage were performed for gallstone pancreatitis, an ulcerated lesion was found in the ampulla of the Vater. Based on the biopsy results, the lesion was diagnosed as the ampulla of Vater carcinoma and subtotal stomach-preserving pancreatoduodenectomy (SSPPD) was performed. Postoperative histopathological examination revealed the coexistence of adenocarcinoma and neuroendocrine carcinoma components, consistent with the diagnosis of MINEN. In addition, lymph node metastasis was found on the dorsal side of the pancreas and the metastatic component was adenocarcinoma. Adjuvant chemotherapy with etoposide and cisplatin was administered for 6 months, and presently the patient is alive without recurrence 64 months after surgery. Case 2: A 79-year-old man presented with a chief complaint of anorexia. Cholangiography showed severe stenosis of the distal bile duct. A biopsy was conducted from the stenotic lesion and it revealed the lesion to be adenocarcinoma. A diagnosis of distal bile duct carcinoma was made, and SSPPD was performed. Histopathological examination revealed the coexistence of adenocarcinoma and neuroendocrine carcinoma components, and the tumor was confirmed as MINEN of the distal bile duct. No adjuvant chemotherapy was administered due to the poor performance status. 7 months later, the patient was found to have a liver metastasis. Conclusion We experienced two valuable cases of biliary MINEN. To identify better treatments, it is important to consider the diversity of individual cases and to continue sharing a variety of cases with different presentations

就寝時マウスガードを使用することによる、再発性アフタ性口内炎に対する予防効果 : 予備的介入研究

Recurrent aphthous stomatitis (RAS) is the most common inflammatory ulceration in the oral mucosa of otherwise healthy individuals and is often accompanied by severe pain. However, the etiology of RAS is not completely understood, and currently, no therapy can completely prevent RAS recurrence. In our clinical experience, we noticed that patients using a night guard, which is often used for bruxism treatment, did not develop RAS. Therefore, the aim of this study was to determine whether mouthguard use can suppress RAS development. The cohort of this interventional, prospective, single‐center, and self‐controlled study included 20 subjects who developed RAS at least once a month. The oral health of all the subjects was recorded for 60 days before and after intervention with a mouthguard. The average number of RAS incidences decreased from 5.5 to 1.0, the average days until healing decreased from 7.3 to 5.6, and the period with RAS decreased from 31.5 to 5.0 with mouthguard use. Mouthguard use may be beneficial for preventing RAS development

Field test of quantum key distribution in the Tokyo QKD Network

A novel secure communication network with quantum key distribution in a metropolitan area is reported. Different QKD schemes are integrated to demonstrate secure TV conferencing over a distance of 45km, stable long-term operation, and application to secure mobile phones.Comment: 21 pages, 19 figure