Spectrogram Visualization with Matlab

The present code is a Matlab function that provides a new unique kind of visual representation of the spectrogram obtained by time-frequency analysis of a given signal x[n], named “iris spectrogram” (irisgram). The results are:
1) irisgram – a circular plot of the spectrogram where the time increase azimuthally (circumferentially) clockwise, the frequency increase radially and the signal level is given axially with a color. The exact location of a given point on the plot could be observed using the Data Cursor.
2) optionally:
- matrix with the complex stft coefficients with time across the columns and frequency across the rows;
- frequency vector;
- time vector.

An example is given in order to clarify the usage of the function. For convenience, the input and output arguments are given in the beginning of the function.

The code is based on the theory described in:

[1] H. Zhivomirov. A Novel Visual Representation of the Signals in the Time-Frequency Domain. The Scientific Bulletin, Series C: Electrical Engineering and Computer Science, ISSN: 2286-3540, Vol. 80, Issue 3, pp. 75-84, 2018. (https://www.scientificbulletin.upb.ro/rev_docs_arhiva/rez786_869448.pdf)