Infrared (also called a infrared scanner, infrared sensor or infrared detector) was equipment used by various races and governments to detect infrared radiation.

In the year 2367 both Tarn and Human forces on Torgu-Va used infrared to detect each other at night. The Tarn infrared scanners were better at detecting than their Human counterparts. The battle jumpsuit used by the Tarn also had an oil that would dissipate an infrared signature. (TNG novel: The Forgotten War)