Glass break detection using ultrasonic signal(s)

A detector for detecting a break in a glass, the detector comprising:

• a speaker and a microphone each configured to be disposed in sound communication with a surface of the glass;
• at least one processor;
• and
• at least one memory storing a plurality of instructions that, when executed by the at least one processor, cause the at least one processor to:
• perform an echo signature procedure to generate a baseline echo signature, the echo signature procedure comprising:
• causing the speaker to, during a first duration, transmit an ultrasonic signal onto the surface of the glass;
• causing the microphone to, during the first duration and during a second duration longer than and overlapping the first duration, measure a plurality of sound wave amplitudes on the surface of the glass;
• generating a sound intensity array comprising a plurality of intensity elements, each of the plurality of intensity elements comprising an intensity value based on a respective one of the plurality of sound wave amplitudes, the plurality of intensity elements being ordered based on a time sequence;
• generating a forward difference array comprising a plurality of difference elements, each of the plurality of difference elements:
• corresponding to a pair of adjacent elements of the sound intensity array;
• and
• comprising a magnitude, the magnitude being based on a difference between the intensity values of the corresponding pair of adjacent elements;
• determining which difference elements of the forward difference array that correspond to respective ones of a plurality of sound intensity peaks, each of the plurality of sound intensity peaks representing an echo of the ultrasonic signal on the surface of the glass;
• generating an echo signature based on a plurality of array positions of the difference elements of the forward difference array that were determined to correspond to the respective ones of the plurality of sound intensity peaks;
• repeat the echo signature procedure to generate a test echo signature;
• compare the baseline echo signature to the test echo signature;
• detect the break in the glass based on the comparison;
• and
• cause an alert to be generated based on the break in the glass being detected.