Patent ID: 6023235
Filing Date: 2000-02-08
Classification: G01S

Abstract:
A method for generating a microwave image of a moving object by using inverse synthetic aperture radar (ISAR) to detect backscatter centers of the object, comprising:providing a two-dimensional location distribution of a plurality of range lines;performing a spectral analysis in each of the range lines for evaluating a Doppler shift, wherein a two dimensional mapping of a reflectivity function of the object is obtained for all of the range lines; andsuppressing interference in the microwave image, the interference including artifact pixels created because of Doppler shifts; the step of suppressing further comprising:(a) identifying pixels which exceed an intensity threshold value as active pixels, andsubjecting only the active pixels to further processing;(b) counting respective numbers of active pixels in individual successive range lines,determining range lines wherein the numbers of active pixels exceed a numerical threshold, anddetermining at least one interfered range area comprising the range lines wherein the numbers of active pixels exceed the numerical threshold and to which further processing is to be restricted;(c) performing image opening in the interfered range area, the image opening further comprising successively performing at least one erosion and at least one dilatation;wherein the erosion comprises canceling each active pixel in a defined vicinity of which an inactive pixel occurs, and the dilatation comprises activating each pixel in the defined vicinity of which an active pixel occurs;and wherein, following any erosion or any dilatation, the defined vicinity of each pixel is freshly determined by applying the same defined vicinity criteria as before the respective erosion or dilatation,whereby a previously performed image processing step has no effect at all on the new vicinity determination.