改进空域同态滤波算法，将图像低通滤波结果反相作为补偿模型来平衡图像的光照非均衡性，减少低频信息的损失；对主要影响同态处理速度的空域滤波进行优化，提出了两种简化计算方法：基于Kronecker积构造2维窗的模板分解方法和基于抽样和插值方案的空域滤波近似方法。仿真结果表明，基于优化计算方案的改进同态滤波快速算法在补偿图像光照非均衡性、降低计算量的同时，有效地保持了图像低频信息，且可通过更多滤波模板实现。

An improved homomorphic spatial filtering algorithm is presented. With the reversed low frequency image this algorithm compensates imbalanced illuminating in the uneven brightness image in order to reduce the loss of low frequency components. Then two optimum schemes about spatial filtering are proposed for efficient processing: a method of 2D window template decomposition, which is constructed by tensor production and an approximate spatial filtering based on sampling and interpolation. Simulation indicates that the improved algorithm with the two optimum methods enhances illuminating uniformity, reduces the computational load and keeps the low frequency components effectively. Besides, it can be performed by more 2D windows.