1. A method in a computer system for filtering 2D or 3D image data, comprising: providing a 3D continuous wavelet transform having a single unknown parameter which is a wavelet width, (a), necessary for transforming a dataset; receiving an input value for the wavelet width, (a); using the 3D continuous wavelet transform and the input value of the wavelet width, (a), to transform a set of up to 3D image data into a correlation image representing correlation strengths, with respect to the wavelet width, (a), as a function of spatial position; and graphically rendering the correlation image to be viewed by a user, whereby high correlation structural features may be discernable by the user in the correlation image.