Understanding Digital Defog Technology

Since surveillance cameras are often installed outside and are expected to stand the test of 24/7 operation, they are frequently exposed to strong light, rain, snow, and fog. These environmental conditions have a great influence on the image quality of the surveillance camera, especially the fog. The aerosol particle containing moisture and fumes in the fog is the main cause for the degrading of the image quality. The low contrast ratio when foggy decreases the image quality so that the details of the scene can’t be seen clearly. Therefore, defog technology is one of the imperative technologies for outdoor surveillance.

At present, one common approach for defogging an image is to use a specific optical component that senses more IR information in fog. One of the liabilities of this physical means is its high cost. Advancements in the development of digital technology brings about the defog image processing technology. This technology adjusts the distribution of the information captured by the image sensor, and enhances the color and details of the surveillance target to decrease the information loss during subsequent processing, such as ISP and encoding compression.

In this paper, we will go through the digital defog technology.

What's inside?

• Background
• Classification of Digital Defog Technology
• Hikvision Digital Defog - Based on atmospheric optics theory
• Defog Technology Applications