1. A method for the reconstruction of an object which has diffracted at least one wave of energy propagating through it, said wave of energy being selected from a group consisting of sonic and electromagnetic waves, comprising the steps of: (a) obtaining signals which are a function of at least one of the phase and amplitude of the diffracted propagating wave after said wave has interacted with said object; and (b) converting said signals by means of a filtered backpropagation technique into an array representing a partial reconstruction of the object.