The development of the lighting profession toward the third stage requires our attention shifting from the light on certain planes to the light distributions in 3D spaces. In this article, we propose a practical strategy to measure the local density of illumination in 3D scenes based on the zeroth-order of spherical harmonics decompositions of a high dynamic range (HDR) panoramic map. The basic functional principle of deriving illuminance density from HDR panoramic maps was presented, and hereinafter named as illuminance panoramic. Illuminance panoramic was compared with Cuttle’s approximated illuminance scalar, which is essentially a physical approximation of the average illumination over a sphere. To verify the measurements, the average illuminance over a sphere, approximated illuminance scalar, illuminance panoramic, cylindrical illuminance, semi-cylindrical illuminance, and horizontal illuminance were simulated via a model (probe in a sphere). The results indicate that the measurement of density of illumination using HDR panoramic maps has well coincided with its definition (i.e., the average illuminance over a sphere) while other illumination values vary with how the probes are located. The measurement theories were later verified using six HDR panoramic maps of real scenes. This research provides confidence in developing applications in mobile phones by capturing HDR panoramic maps to measure the density of illumination in 3D spaces.

照明行业向第三阶段的发展需要我们将注意力从某些平面上的光转移到 3D 空间中的光分布。在本文中，我们提出了一种基于高动态范围 (HDR) 全景图的球谐函数分解的零阶测量 3D 场景中局部照明密度的实用策略。介绍了从HDR全景图推导照度密度的基本功能原理，以下简称照度全景。将全景照度与卡特尔的近似照度标量进行比较，后者本质上是球体上平均照度的物理近似值。为了验证测量结果，球体上的平均照度、近似照度标量、全景照度、柱面照度、半圆柱照度和水平照度通过模型（球体中的探头）进行模拟。结果表明，使用 HDR 全景图测量照明密度与其定义（即球体上的平均照度）非常吻合，而其他照明值随探头的定位方式而变化。后来使用六个真实场景的 HDR 全景图验证了测量理论。这项研究通过捕获 HDR 全景图来测量 3D 空间中的照明密度，为开发手机应用程序提供了信心。球体上的平均照度），而其他照度值随探头的位置而变化。后来使用六个真实场景的 HDR 全景图验证了测量理论。这项研究通过捕获 HDR 全景图来测量 3D 空间中的照明密度，为开发手机应用程序提供了信心。球体上的平均照度），而其他照度值随探头的位置而变化。后来使用六个真实场景的 HDR 全景图验证了测量理论。这项研究通过捕获 HDR 全景图来测量 3D 空间中的照明密度，为开发手机应用程序提供了信心。