Infrared is radiation beyond the red end of the visible spectrum. The utility of infrared surveillance lies in the fact that we can observe with a camera aspects of a scene that would otherwise be completely undetected by the eye.

Near Infrared

• Must illuminate the scene with a near infrared light source
• Images appear similar to a visible scene
• Low cost - some b/w cameras can be used

Thermal Infrared

• No illumination required (uses object's own radiation)
• Unnatural images
• More expensive