Low-light and infrared images are often interfered by various external noises in the process of shooting, sampling, quantization and transmission, so that the images cannot truly reflect the scene, and the image quality is seriously degraded. In image processing, image filtering plays an important role. It can effectively suppress various noises and preserve edge information, thereby improving the quality of subsequent processing work. Therefore, image noise filtering becomes an important part of image preprocessing.

Several common image denoising filtering methods are introduced below.

1. Mean filter

2. Neutral filter

3. Hybrid denoising method