Interstellar space behaves as an almost perfect blackbody radiator, at a temperature of 2.725 Kelvin, due to the cosmic microwave background. As such, it does "emit heat", albeit an extremely small, but measurable amount.
Let me answer your question with a question: Does the infrared camera detect emitted heat?
Not clear where your question is coming from, but it detects heat that's emitted as infrared radiation.