Lighting measurement with a 360° panoramic camera: Part 1 – Technical procedure and validation

Abstract

This study developed a 360° field of view (FOV) lighting measurement method with the aid of the Ricoh Theta Z1 panoramic camera. As versatile lighting information from all viewing directions within 360° FOV can be retrieved from a single 360° high dynamic range (HDR) image, this new method improves the lighting measurement efficiency. Part 1 of this study reported in the present paper focuses on technical procedure and validation. Firstly, all technical issues were solved for using the Theta Z1 camera to conduct 360° FOV lighting measurement with a provided and validated step-by-step procedure. A new illuminance measurement method was then developed with the aid of the Theta Z1 camera for calculating all directional illuminance data at the camera measurement point from any viewing direction within the 360° panoramic FOV, retrieved from a single 360° HDR image taken in the field. This 360° FOV lighting measurement method has average error rate of 4.0% ± 2.4% for luminance measurement and 3.1% ± 2.6% for illuminance measurement in building interiors. Reported outcomes include the detailed procedure and algorithms for the configuration, calibrations and post-image processing, and corresponding MATLAB code and Python programs are shared online.