Does ultrasound require knowing the emissivity of a material?
No, emissivity is a unique requirement to optical thermal measurement such as pyrometers and IR imaging. Because the emissivity of a material can change with temperature or due to chemical processes at high temperatures, pyrometers and IR imaging may not work well or at all in certain situations. Because of this, Ultrasonic Thermometry is better suited for extreme high temperature thermal monitoring in many situations.
