On the use of a consumer-grade 360-degree camera as a radiometer for scientific applications: calibration dataset

Studying the geometric distribution of the light field in terms of absolute radiometry required expensive and complex instruments. New types of compact 360-degree cameras have recently appeared on the consumer technology market. Some of these allow users to access raw imagery, offering sensor-level data that can be directly exploited for absolute light quantification. This paves the way for easy-to-use, inexpensive and accessible radiance cameras that can be operated in a wide range of natural environments. This dataset presents raw format images captured with the camera Insta360 ONE for its calibration and characterization. These experiments include geometric calibration, relative illumination evaluation, spectral response determination, absolute spectral radiance calibration, as well as linearity and dark frame analysis. In addition, we are providing data from a calibration validation experiment based on co-located measurements of the sky's downward radiance using a 360-degree calibrated camera and a scientific radiometer: the Compact Optical Profiling System (C-OPS, Biospherical Instruments Inc.). This repository contains raw files as taken by the camera's imaging sensor. In most cases, no data processing has been carried out. The entire data set is contained in a .zip file which includes the following sub-folders (in alphabetical order): absolute-radiance: data (.dng, .tsv , .hdf5) acquired for absolute spectral radiance calibration darkframe: DNG raw images taken for dark frame analysis geometric: DNG images used for the geometric calibration immersion-factor: DNG images for the calculation of the immersion factor linearity: DNG images for linearity assessment (gain and exposure time) relative-illumination: DNG images for roll-off (relative illumination) characterization relative-spectral-response: data (.asc, .dng) taken for relative spectral response characterization verification&validation: time series data (.tsv, .dng) of the calibration validation experiment Each folder contains a README file explaining the additional subfolders and their files. As you may notice, some of the subfolders are named "lensclose" or "lensfar". They refers to the data acquired with the fish-eye optic assembly that is closer or farther from the top of the 360-degree camera respectively. Some calibrations were performed both in water and in air (geometric calibration, relative-illumination). In that regard, the images were placed in folders refering to "air" and "water". The routines (coded in python) for the data processing can be found in the following Github repository (master_v01) or the Zenodo stored version. The useful scripts are located in the calibration directory, and the README for each folder points to the revelant code for analysis of the files they contain. For additional information, all the methodologies are described in the arXiv preprint.基于绝对辐射测量（absolute radiometry）开展光场几何分布研究，往往需要昂贵且复杂的专业设备。近年来，消费级科技市场涌现出多款紧凑型360°相机，其中部分机型支持用户获取原始影像，可提供可直接用于绝对光量化的传感器级数据。这为可在多种自然环境中部署的易用、低成本且易获取的辐射相机（radiance camera）铺平了道路。 本数据集收录了使用Insta360 ONE相机拍摄的原始格式影像，用于该相机的标定与特性表征。相关实验涵盖几何标定、相对照度评估、光谱响应测定、绝对光谱辐射标定，以及线性度与暗帧分析。此外，本数据集还包含一项标定验证实验的相关数据：该实验通过同步测量天空下行辐射，结合360°标定相机与科学辐射计Compact Optical Profiling System（C-OPS, Biospherical Instruments Inc.）完成。 本仓库收录了相机成像传感器直接输出的原始文件，绝大多数未经过任何数据处理。完整数据集存储于一个.zip压缩包中，按字母顺序排列的子文件夹如下： absolute-radiance：用于绝对光谱辐射标定的数据集（文件格式为.dng、.tsv、.hdf5） darkframe：用于暗帧分析的DNG格式原始影像 geometric：用于几何标定的DNG格式影像 immersion-factor：用于浸没因子计算的DNG格式影像 linearity：用于线性度评估（含增益与曝光时间参数）的DNG格式影像 relative-illumination：用于渐晕（相对照度）特性表征的DNG格式影像 relative-spectral-response：用于相对光谱响应特性表征的数据集（文件格式为.asc、.dng） verification&validation：标定验证实验的时间序列数据（文件格式为.tsv、.dng） 每个子文件夹均包含README文件，用于说明其下的次级子文件夹与对应文件。部分次级子文件夹名为“lensclose”或“lensfar”，分别对应鱼眼光学组件贴近360°相机顶部与远离相机顶部时采集的数据。部分标定实验（如几何标定、相对照度标定）同时在空气与水环境中开展，因此相关影像被分别存入标注为“air”与“water”的文件夹中。本数据集的数据处理Python代码可从以下GitHub仓库（master_v01）或Zenodo存档版本获取：实用脚本均存储于calibration目录下，每个子文件夹的README文件均指向用于分析其内含文件的对应代码。如需了解更多细节，所有研究方法均已在arXiv预印本中详细阐述。