Which type of sensor is used to detect metal objects?

Magnetic Vehicle Detection sensors are specifically designed to detect metal objects by sensing changes in the earth's magnetic field caused by the presence of ferrous materials, such as vehicles. These sensors are particularly effective for monitoring the movement of vehicles in border security operations, as they can identify the metallic components of vehicles that pass overhead or nearby.

In contrast, the other types of sensors listed serve different functions. Seismic Point sensors are used to detect vibrations caused by movement in the ground, which can indicate human or vehicle presence but not specifically focus on metal detection. Infrared Detection relies on temperature differences to identify objects, which makes it less effective for metal detection. Lastly, Acoustic Detection utilizes sound waves to detect changes in the environment but does not directly measure the presence of metal objects. The specific design and functionality of Magnetic Vehicle Detection make it the appropriate choice for detecting metal objects within border patrol operations.