Three-parameter chirp atoms based on rotated radial-shift operator and searching strategy of the best ones in matching pursuit

In tins paper, the new three-parameter chirp atoms with the scale, the rotation and the radial-shift, is proposed and the searching strategy of die best chirp atoms in die matching pursuit is presented. This strategy first estimates linear chirp-rate of the chirp atom by applying die fractional Fourier transform to the signal to be analyzed and then shifts radially the signal along estimated orientation to regulate the time-frequency center, so that the best chirp atoms are obtained. Thanking to estimating and grasping the most time-frequency structure in advance, the searching strategy not only reduced the size of the chirp dictionary and economized the time of searching the best atoms, but also avoided the inherent greed decomposition of the original MP and provided die most time-frequency information existing in the signal.