全场彩虹技术是一种有效地同时测量雾化液滴粒径分布及折射率的方法，但现有算法或多或少地存在一些不足之处，故提出一种基于最小二乘法及优化过程的全场彩虹技术反演算法。从拍摄的全场彩虹中提取若干特征信息来估计粒径分布范围及折射率的初始值，用于构建线性方程组；通过最小二乘法解方程组获得粒径分布，并根据结果重构全场彩虹；基于所提出的优化过程不断调整粒径分布范围及折射率，最终得到较为准确的粒径分布及折射率。通过数值计算和实验研究验证了该算法的可行性，结果表明折射率的反演误差在10-4量级，反演的平均粒径的误差小于3 μm，反演的粒径分布与真实情况一致。

Global rainbow technique (GRT) is an effective method for the simultaneous measurement of the size distribution and refractive index of the spray droplets. However, there are some shortcomings in the existing algorithm. An improved reversion algorithm of GRT is proposed based on the least square method and optimization process. The features are extracted from the intensity distribution of the captured global rainbow to estimate the initial value of the size distribution and refractive index of the droplets, so as to build the linear equations. The linear equations are solved by the least square method to get the particle size distribution, and global rainbow is reconstituted according to the results. The refractive index and size distribution of the droplets are optimized according to the angular deviation between the reconstructed and captured rainbows. Both numerical simulations and experiments are carried out to evaluate the feasibility of the improved algorithm. The results show that the error of the inversion result of refractive index is of the order of magnitude 10-4, and the error of the mean diameter is better than 3 μm, and the reverse grain diameter is in accordance with the true value.