The night vision used in Silence of the Lambs was an early form of infrared imaging. It worked by detecting the infrared radiation emitted by objects and then converting it into an electrical signal. This signal was then displayed on a screen, which made it appear as if the objects were glowing in the dark. Early forms of infrared imaging were not very sensitive, so they could only be used to see relatively large objects. However, they were still useful for tasks such as tracking enemy soldiers at night. The night vision used in Silence of the Lambs was state-of-the-art at the time, but it would now be considered quite primitive by today's standards. Modern day infrared cameras are much more sensitive and can be used to see even small objects in low light conditions.