When we talk security cameras in Chicago, night vision almost always comes up. In the Fall and Winter, we get some long nights. When it’s not freezing, that leaves ample opportunity for burglars to operate at night. One of the most talked about needs is being able to see at night, but not just this. A night-vision camera should also be able to act as a deterrent when you need it to. So, what are the differences between different modes of seeing at night: thermal vs. active IR?
Thermal Imaging Security Cameras
Thermal imaging cameras are passive. They sense differences in heat that are happening in their field of view. Yet they don’t project any light. Heat signatures are represented visually as white when they’re hot and black when they’re cold, with varying colors in between to represent heat levels in between. How is this useful?
Thermal imaging cameras detect in long wavelengths of infrared. This means that they don’t see many other sources of light. Dust, smoke, and other light sources won’t interfere with their being able to capture an image. This makes them tremendously useful in capturing images at a distance, and this is why they’re often used along barriers and fences.
The downside is that thermal imaging is typically more expensive than active IR, which is suitable for a number of other environments. What is active IR?
Active IR Security Cameras
Active IR cameras use infrared LEDs to cast infrared light over an area. The camera itself relies on this infrared light getting reflected back at it. Thus, it is dependent upon the coverage of the infrared light it projects. This means that it’s very useful for seeing at night in a parking lot or alley, but doesn’t have the extensive range of thermal imaging.
Unlike a thermal imaging camera, active IR won’t pierce dust or haze in the same way. This is because dust and haze will reflect the infrared light being projected right back at the camera. Thermal imaging avoids this because it’s simply looking for the heat an object emanates, and dust and haze don’t emanate much heat. They will reflect light, however, which is what active IR relies upon.
The infrared light active IR projects is invisible to the naked eye. Because cameras work so well as deterrents, there are infrared LEDs that can be made visible at night. Active IR is less expensive and more suitable for many situations, while thermal imaging is more powerful but really only needed for precise circumstances.
When it comes to security cameras in Chicago, and thermal vs. active IR, the deciding factor is the context. Different locations lend themselves to different night-vision cameras.