Energy band method for processing acoustic data

A non-transitory computer readable medium, storing instructions executable by a computer processor, the instructions comprising functionality for:

• receiving an acoustic signal;
• transforming the acoustic signal into a frequency spectrum using a frequency transformer, wherein the frequency spectrum comprises a plurality of frequency data points;
• partitioning the plurality of frequency data points into a plurality of energy bands using an energy band partitioning function configured to:
• identify a plurality of peak data points in the plurality of frequency data points, wherein each peak data point has a higher amplitude than a respective adjacent frequency data point,
• select a plurality of selected peak data points from the plurality of peak data points, wherein each selected peak data point has a predetermined minimum number of frequency data points nearby the selected peak data point, and
• determine the plurality of energy bands, wherein:
• each energy band contains a respective selected peak data point and nearby frequency data points based on the predetermined minimum number of frequency data points,
• adjacent energy bands are separated by a respective lowest frequency data point that has a lower amplitude than a frequency data point adjacent to the respective lowest frequency data point,
• any frequency data point that has an amplitude of zero is excluded from the plurality of energy bands;
• determining a representative frequency for each of the plurality of energy bands;
• determining a representative amplitude for each of the plurality of energy bands, wherein the representative amplitude is determined based on an energy conservation principle and the respective representative frequency;
• determining an energy band series, wherein the energy band series comprises the representative amplitude and the representative frequency for each of the plurality of energy bands;
• and
• determining, using the energy band series, an acoustic signal characteristic.

A system, comprising:

• a drilling system comprising:
• a drill bit configured to cut a rock, and
• an operations system configured to monitor and control drilling operations, the operations system configured to measure and record, at least, a rotation speed of the drill bit and a depth of the drill bit;
• an acoustic signal recording system configured to receive and record an acoustic signal;
• and
• a computer, comprising one or more computer processors and a non-transitory computer readable medium storing instructions executable by the one or more computer processors, the instructions comprising functionality for:
• transforming the acoustic signal into a frequency spectrum using a frequency transformer, wherein the frequency spectrum comprises a plurality of frequency data points;
• partitioning the plurality of frequency data points into a plurality of energy bands using an energy band partitioning function configured to:
• identify a plurality of peak data points in the plurality of frequency data points, wherein each peak data point has a higher amplitude than a respective adjacent frequency data point,
• select a plurality of selected peak data points from the plurality of peak data points, wherein each selected peak data point has a predetermined minimum number of frequency data points nearby the selected peak data point, and
• determine the plurality of energy bands, wherein:
• each energy band contains a respective selected peak data point and nearby frequency data points based on the predetermined minimum number of frequency data points,
• adjacent energy bands are separated by a respective lowest frequency data point that has a lower amplitude than a frequency data point adjacent to the respective lowest frequency data point,
• any frequency data point that has an amplitude of zero is excluded from the plurality of energy bands;
• determining a representative frequency for each of the plurality of energy bands;
• determining a representative amplitude for each of the plurality of energy bands, wherein the representative amplitude is determined based on an energy conservation principle and the respective representative frequency;
• determining an energy band series, wherein the energy band series comprises the representative amplitude and the representative frequency for each for each of the plurality of energy bands;
• and
• determining, using the energy band series, an acoustic signal characteristic.