直线道路的 r（x，y）反射表和亮度计算

摘要

亮度评价方法在道路照明评价中变得越来越重要，但有关亮度的计算工作却十分缺乏。虽然用CIE （国际照明委员会）提供的路面反射表r（β，γ）可以计算道路的亮度分布，但其实际的计算过程却很困难。分析其困难的根本原因是在于道路亮度分布是基于直角坐标而CIE的反射表却基于球坐标。本文引入了一个新的基于直角坐标的路面反射表，称为r （ x， y）表。用r （ x， y）表分析路面反射特性将更直观、形象而且更具有系统性，计算直线道路亮度分布也更容易。文章给出了r （ x， y）表的导入方法，详细分析了不同路面性质时在沿道路方向和垂直道路方向上的反射系数变化规律，以及用r （ x， y）表方便地计算单个车道和整个道路的亮度分布的方法。这将大大有利于分析给定灯具时道路的亮度如何分布，以及如何设计等亮度分布的灯具。%Luminance evaluation is becoming more and more important in the road lighting evaluation, but the calculation work is lack to be seen in publication. Although the calculation of road-luminance distribution can be conducted using the luminance coefficients r (β, γ) table stipulated by CIE ( International Commission on Illumination ) , it remains a very difficult process.The root cause of the difficulty is that road-luminance distributions employ Cartesian coordinates, whereas the r (β, γ) table is based on spherical coordinates.A new luminance-coefficient table for straight road called r ( x, y) table based on Cartesian coordinates is introduced in this paper.This provides a new simple and visualized method for luminance calculation.The analysis of pavement reflection properties will be more intuitive visualization and the calculation of road luminance distribution also will be easier.The derivation method of r (x, y) table was given, and the analysis of the reflection coefficient in different pavement properties along the road direction and the vertical direction are discussed in detail.It is easy to calculate the luminance distribution of the single lane and whole road using r ( x, y) table.This will be a huge boost to analyze the road luminance distribution with given luminaire, as well as designing luminaires with isoluminance.