Patent ID: 7728254

Claim:
A method for controlling quality of a manufacturing process for recognizing defects in result of a production, the method comprising: acquiring, by detecting one or more quantity of the production of said manufacturing process, one or more real signals produced by a machine involved in the manufacturing process, where the one or more real signals are indicative of the quality of said manufacturing process; providing one or more reference signals corresponding to said one or more real signals and indicative of a good-quality process for the manufacturing process; obtaining a transformed signal from said reference signal; obtaining a transformed signal from said real signal; converting each of the transformed real signal and the transformed reference signal into a respective vector of energies, where the vector of energies comprises an integer number k of frequency values; and comparing said one or more reference signals with said one or more real signals in order to identify the defects in the result of the production, wherein said comparing comprises: comparing said vector of energies of said transformed reference signal with said vector of energies of said transformed real signal and selecting frequency values among said k frequency values on the basis of said comparison, respectively, for extracting corresponding time-frequency distributions for said selected frequency values; calculating energies of said time-frequency distributions; and comparing the energies of said time-frequency distributions with threshold values in order identify energy values associated with said defects, and the corresponding time coordinates of said defects.