Sky view factor (SVF) is a ratio of sky in upper hemisphere and is an important index for many environmental studies. Frequently used method for measuring SVF is taking fisheye image of upper hemisphere by a camera with fisheye lens (Nikon FC-E8 and FC-E9). In this study, we devised the usage of a spherical camera (RICOH Theta S), which can takes a picture with 360° field of view (FOV), for SVF measurement. Applicability of the spherical camera to the measurement of SVF is tested by comparing with conventional fisheye cameras. The result showed that it can take the same quality of fisheye images as conventional fisheye camera and can be applied to the measurement of SVF. Accuracy and causes of errors are considered and as a conclusion, the spherical camera has enough performance for the replacement of conventional cameras. The algorithm of making fisheye images of different projection methods and of calculating SVF are written as programs in R.

中文翻译：

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使用球形相机测量天空视角因子

天空视角因子（SVF）是上半球天空的比率，是许多环境研究的重要指标。测量 SVF 的常用方法是使用带鱼眼镜头的相机（尼康 FC-E8 和 FC-E9）拍摄上半球的鱼眼图像。在这项研究中，我们设计了使用球形相机 (RICOH Theta S) 进行 SVF 测量，它可以拍摄 360° 视野 (FOV) 的照片。通过与传统鱼眼相机的对比，检验了球形相机在SVF测量中的适用性。结果表明，它可以拍摄出与传统鱼眼相机相同质量的鱼眼图像，可以应用于SVF的测量。考虑了精度和误差原因，作为结论，球形相机具有足够的性能来替代传统相机。