Non-contact temperature sensors, such as IR thermometers, detect infrared energy emitted by a target and offer rapid response times. These devices are ideal for measuring temperatures of moving or intermittent targets, objects in a vacuum, or environments that are difficult or hazardous to access due to geometric or safety constraints. They are cost-effective and widely used, respond quickly, and do not interfere with the target.

Understanding the fundamentals of infrared thermometry is crucial for designing an accurate monitoring system. To avoid misconceptions and the dismissal of non-contact temperature measurements as unreliable, this section focuses on the physical principles of infrared.