Multi-scale enveloping spectrogram signal processing for condition monitoring and the like

A method of signal processing, said method comprising the steps of:

• (a) obtaining a signal from physical phenomena to monitor operation of an underlying system, wherein the signal is provided from a sensor monitoring a condition of a machine and/or machine component or a condition in a physiological system and the signal is indicative of the condition being monitored;
• (b) processing the signal using a continuous wavelet transform at a plurality of different scales;
• (c) extracting signal envelope for the processed signal for each scale;
• (d) applying spectral analysis to the extracted envelopes to determine the frequency compositions thereof;
• (e) generating a three-dimensional frequency map from the determined frequency compositions;
• and
• (f) displaying the three-dimensional frequency map, whereby the signal provided by the sensor is transformed into a visual presentation that indicates the intensity and location of defect-induced or condition-induced frequencies that are indicative of the condition being monitored.

A system for processing a signal, said system comprising:

• a sensor for obtaining a signal from physical phenomena to monitor operation of an underlying system, wherein the sensor is monitoring a condition of a machine and/or machine component or a condition in a physiological system, and the signal is indicative of the condition being monitored;
• a processor adapted to receive the signal provided by the sensor,
• an output display coupled to the processor;
• the processor being programmed to:
• (a) process the signal using a continuous wavelet transform at a plurality of different scales;
• (b) extract signal envelopes for the processed signal for each scale;
• (c) apply spectral analysis to the extracted envelopes to determine the frequency compositions thereof;
• (d) generate a three-dimensional frequency map from the determined frequency compositions;
• and
• (e) display the three-dimensional frequency map on the output display, whereby the signal provided by the sensor is transformed into a visual presentation that indicates the intensity and location of defect-induced or condition-induced frequencies that are indicative of the condition being monitored.