为处理4f 相干光图像处理系统中存在的随机噪声和低频相干噪声，提出一种基于多谱点图像融合的相干光图像处理系统降噪方法。先利用空间光调制器的点阵结构带来的图像复制功能，在同一次试验中获取多个谱点图像，其中各图像包含有相同的图像信息和同分布规律但不同数值形式的噪声信息。再使用图像融合技术将这些图像合并，用类似于时域累积平均的方式淡化随机噪声和相干噪声。理论分析和物理实验表明，该方法既能处理随机噪声，又能有效处理低频段的相干噪声，并且对图像信息几乎没有损失。

To remove the random noise and low-frequency coherent noise in the images of 4f coherent optic image processing system, a method based on fusion of multiple spatial frequency spectrum images is proposed. Firstly, capture the multiple spatial frequency spectrum images of once experiment based on the image copying character form the lattice structure of spatial light modulators. These images contain the same useful image information and noise with the similar distribution but different values. Then, these images are combined by image fusion algorithm whose principle is approximate to the time-domain cumulative mean method to remove the noise. The theoretical analysis and physics experiments show that the method can remove the random noise and diluted the low-frequency coherent noise well, and almost no harm to the useful image information.