New instantaneous frequency estimation method based on image processing techniques

The aim of this paper is to present a new method for the estimation of the instantaneous frequency of a frequency modulated signal, corrupted by additive noise. Any time-frequency representation of an acquired signal is concentrated around the instantaneous frequency law of its useful component (the projection of the ridges of the time-frequency representation on the time-frequency plane) and realizes the diffusion of its noise component. So, extracting the ridges of the time-frequency representation, the instantaneous frequency of its useful component can be estimated. In this paper a new time-frequency representation is proposed. Using the image of this new time-frequency representation, its ridges can be extracted with the aid of some mathematical morphology operators. This is a ridges detection mechanism producing the projection on the timefrequency plane. This projection represents the result of the proposed estimation method. Some simulations prove the qualities of this method. © 2005 SPIE and IS&T. [DOI: 10.1117/1.1901677]