About Virtual Sensors
Description
A virtual sensor uses information available from other measurements and process parameters to calculate an estimate of the quantity of interest. (Wikipedia) For example a virtual sensor might measure many different readings from a person in order to try to determine if a person was happy or sad or angry or scared.
Virtual sensing techniques, also called soft sensing, proxy sensing, inferential sensing, or surrogate sensing, are used to provide feasible and economical alternatives to costly or impractical physical measurement instrument. (Wikipedia