The use of density functions of signal energy distribution on the frequency-time plane provides the new possibilities on estimation of signal parameters under conditions of the high noise level and concentrated interferences. A technique is given for frequency-time signal processing to solve a problem of parameters estimation. Expedience of using density functions of energy distribution for estimation of the instant frequency parameters in watching algorithms of frequency-time analysis is substantiated. In technique realization on a computer a procedure of distributions of spline-approximation on the basis of minimal form splines is suggested to increase the rate of data processing.