ATMOSPHERIC VARIABLE COMPENSATION FOR AN AUTOMATED INSPECTION SYSTEM

摘要

A phase-monitoring type of acoustic inspection system includes acoustic transducers (21) to transmit and receive continuous acoustic waves at a constant frequency, a detector (45) to detect changes in phase or amplitude, or both, of acoustic waves reflected at different times from a fixed reference target through an isothermal transmission medium, and a conditioning system (25) to control the temperature of the acoustic transmission path in response to the detected changes associated with the reference target to maintain the wavelength of acoustic waves constant regardless of changes in humidity and barometric pressure along acoustic transmission paths.