魚眼レンズ付デジタルカメラによる紫外•可視•近赤外域の全天空分光放射輝度分布の測定法

摘要

温暖化や節電の影響を受けて、エネルギー消費量を抑えた照明システムが求められている。昼光照明は、人工照明によるエネルギー消費削減が可能である一方、夏季の日射熱取得の増大に伴う冷房負荷の増加、紫外放射の人体や家具への悪影響など相反する問題もある。今後の昼光照明設計では、季節•時間•天気•方位によって様々に変動する昼光光源を、可視域だけでなく、紫外域、近赤外域まで連続的に取り扱い、建築環境の各種設計指標の予測計算と評価を行って最適解を見出すことが求められる。%In the previous papers, we have developed a method of measuring the visible spectral radiance of all sky elements using a general purpose digital camera with a fish-eye lens. In this paper, we expanded this method and measured the ultraviolet (UV), visible (VIS) and near-infrared (NIR) spectral radiance of all sky elements with the same fisheye camera. The fish-eye camera is portable for field measurements in various climates. We improved the way of colorimetrical calibration of the fisheye digital camera. The calibrated camera measures the all sky distribution of the XYZ tristimulus values more accurately. The XYZ tristimulus values are transferred into the xy choromaticity coordinates. On the other hand, the UV, VIS and NIR spectral radiance of the sky elements is measured by a spectroradiometer under various weather conditions. The eigenvectors of measured spectral radiance are calculated by principal component analysis. Using the eigenvectors, the relative spectral power distribution is computed and then transferred into the all sky distribution of UV, VIS and NIR spectral radiance by tristimulus values Y [cd/m~2].