METHOD AND SYSTEM FOR PROCESSING MEASUREMENT SIGNALS TO OBTAIN A VALUE FOR A PHYSICAL PARAMETER

摘要

A method and system are disclosed for processing time-varying measurement signals (28) to obtain a value for a physical parameter by extracting frequency information from the signals (28). The frequency information includes at least one desired frequency. The frequency information is converted to a value for the physical parameter. Extraction is performed by transforming discrete time ultrasonic signals to a Z-domain (182) and converting at least one zero or pole in the Z-domain to the desired frequency and its decay rate. The measurement signals may be coherent light signals (24, 26, 28) which are frequency modulated based on the propagation of longitudinal waves in the object. For a static film, the physical parameter may be thickness of a cured layer. When the object is a dynamic curable film, its thickness changes over time from an initial value, to an intermediate value, and to a final value.