What is Defog Camera?

Long-range zoom cameras, including PTZ cameras and EO/IR cameras, typically possess defogging capabilities, making them widely utilized in defense and military applications to maximize visibility. There are primarily two types of fog penetration technology employed in these cameras:

Defog OFF and ON

1.Optical defog camera

Normal visible light is unable to traverse clouds and smoke, whereas near-infrared rays possess the ability to penetrate through a certain density of mist and smoke. The technology of optical fog penetration relies on the principle that near-infrared rays can diffract minute particles, enabling precise and swift focusing. The crux of this technology lies primarily in the lens and filter, which, through physical means, harness the principles of optical imaging to enhance image clarity. However, a limitation of this approach is that it primarily produces black and white monitoring images.

2.Electric Defog Camera

Algorithmic fog penetration technology, also known as video image anti-reflection technology, generally refers to clearing the hazy image caused by fog, moisture and dust, emphasizing some interesting features in the image, and suppressing uninteresting features. Makes the quality of the image improved and the amount of information enhanced.

How to achieve defog features by ICR switch?

Many cameras use optical and electric defog together, for example, there are 3 filters in super long range zoom camera:

A: IR-cut filter

B: All pass filter (cut off just some Impurities）

C: Optical defog filter (pass only more than 750nm IR)

In color mode (with fog filter or without it), “A” in front of the sensor

In B&W mode and with fog filter OFF, “B” in front of the sensor

In B&W mode and with fog filter ON, “C” is in front of the sensor (OPTICAL DEFOG MODE)

So when in B&W mode, and digital defog NO, OPTICAL DEFOG active.

But for some normal range digital zoom cameras, it has only 2 filters:

A: IR-cut filter

C: Optical defog filter (pass only more than 750nm IR)

In colour mode (with fog filter or without it), “A” in front of the sensor

In B&W mode and with fog filter OFF, “C” in front of the sensor (OPTICAL DEFOG MODE)

In B&W mode and with fog filter ON, “C” in front of the sensor (OPTICAL DEFOG MODE)

So when in B&W mode, OPTICAL DEFOG active, no matter digital defog cameras ON or OFF.