针对室内照明,提出了一种基于数码相机图像的眩光测量方法。系统推导了眩光源位置指数、立体角、眩光源平均亮度的解析表达式,采用自适应阈值方法提取眩光源轮廓信息,并对实际办公室照明场景的统一眩光评价指数(UGR)进行计算与分析。实验结果表明:由该方法计算的位置指数、立体角、眩光源平均亮度的平均相对误差分别为1.319%,4.296%,3.001%;当背景亮度为12.910 cd·m ^-2时,UGR的计算值为12.606,其相对误差为4.326%。该方法计算简单、精度高,易于硬件实现,可应用室内照明的眩光测试与分析,并为开发方便、快捷的眩光测试系统提供了理论支撑。

A digital imaging method is proposed to measure the uncomfortable glare in interior lighting. Our study includes the systematic derivation of three parameters: the position index, solid angle from the viewer's perspective, and average luminance of glare source. To extract the profile information of the lighting sources, an adaptive threshold method was employed. The Unified Glare Rating (UGR) was calculated and analyzed with a digital camera image of actual office lighting conditions. The results show that the mean relative errors of the obtained position index, solid angle, and average luminance of the glare source were equal to 1.319%, 4.296%, and 3.001%, respectively. For a background luminance of 12.910 cd·m -2, the calculated value of the UGR was equal to 12.606, with a relative error of 4.326%. The advantages of this method are its simple calculations, high accuracy, and easy implementation. By applying our method to the glare test in indoor lighting, a theoretical framework for the development of a convenient and fast glare test system can be constructed.