| Abstract: | Various authors have recently studied the Walsh and Hadamard transforms for functions with one or two variables. Like the Fourier transform they may be obtained by using the Cooley-Tukey algorithm. They can be calculated all the faster because Walsh functions have only values equal to + 1 or ? 1. The complex number multiplications in the Fourier transform are replaced by additions and subtractions of real numbers. These transforms are more general than that of Fourier because the concept of sequency, i.e. the mean number of zeros per time unit, is substituted for that of frequency. These transforms already have numerous applications to signal transmission. We describe some in the field of seismic prospecting, in particular the compression of the information contained in seismic traces. |
