System for detecting occurrence period of cyclical event

A system for detecting occurrence period of cyclical event, applied to detect an event occurrence period of a cyclical event, comprising:

• an image monitoring device, configured for capturing periodically a plurality of monitoring images at a plurality of image capturing times from a monitoring field according to an image capturing period, so as to form in series a dynamic surveillance image data, the cyclical event being occurred in the monitoring field;
• and
• a period judgment device, communicatively connected with the image monitoring device, furnished with a judgment program, the judgment program being executed to create:
• a feature-vector capturing module, configured for capturing the dynamic surveillance image data from the image monitoring device, and further for capturing a plurality of feature vectors of the plurality of monitoring images corresponding to the plurality of image capturing times from the dynamic surveillance image data by utilizing a mathematical operation model generated through deep learning;
• a signal generation module, configured for calculating the plurality of feature vectors to obtain a plurality of vector values according to an occurrence order of the plurality of image capturing times, and further for generating a vector-value time domain signal according to the plurality of image capturing times and the plurality of vector values;
• a spectrum conversion and analysis module, configured for generating a spectrogram by applying a short-time Fourier transform upon the vector-value time domain signal through a plurality of window widths, the spectrogram including a plurality of composition frequencies and correspondingly a plurality of composition-frequency signals and a plurality of composition-frequency amplitudes;
• a noise filtration module, configured for filtering at least one noise signal corresponding to part of the plurality of composition frequencies, capturing the rest of the plurality of composition-frequency signals corresponding to the rest of the plurality of composition frequencies (defined as a plurality of valid composition-frequency signals), capturing one of the plurality of valid composition-frequency signals having the maximum amplitude from each of the plurality of window widths, defining a composition frequency of the one of the plurality of valid composition-frequency signals having the maximum amplitude as a representative frequency for the instant window width, and generating accordingly a representative frequency time domain signal;
• and
• an event-occurrence period judgment module, configured for calculating a plurality of event occurrence times for further determining the event occurrence period according to the representative frequency time domain signals and the plurality of window widths.