Grating array processing methods and apparatus

Abstract

The spectral content of the interference response at a sensor array is taken into account and used to advantage in remote sensing or imaging an object or scene. The phase relationship between sensor elements is preserved, enabling the natural interference spectrum to be processed to generate a particular spatial response of the aggregate beam pattern. The method applies to diverse forms of broadband illumination or emissions including acoustic and electromagnetic radiation, and provides remote sensing capabilities linked to the sensor elements appropriate to the wavelength band of interest (e.g., acoustic, RF or optical). Since the relative geometry between the source, scene and sensing array is responsible for the generation of a desirable interference response, the source of illumination need only maintain a small degree of coherence (some finite correlation length), and can operate in a pulsed or continuous (CW) mode. For passive sensing, the method can be applied to emissions derived from the object/scene itself. The processing technique exploits specific frequency/time domain features of the interference response and can apply them to a number of useful purposes including: 1) remote imaging of a scene, 2) remote characterization of an object of interest and 3) characterization of an intervening media between a source and the sensor array.