Method and apparatus for detection of moving objects by SAR images
AssigneeSelex Galileo Limited
InventorAngelo Aprile
Life of this patent
Estimating the term…
Abstract
A method for the detection of moving objects by SAR images envisages the steps of: generating a pulse-repetition frequency signal starting from a radar signal; and generating a sequence of SAR images starting from the pulse-repetition frequency signal. In particular, SAR images with low azimuth resolution are generated by of coherent integration of the pulse-repetition frequency signal for a sub-aperture time shorter than an aperture time. In addition, the method envisages generating difference images through point-to-point difference between subsequent low azimuth resolution SAR images, and recognizing patterns associated to moving objects in the difference images.
Claims19
A method for the detection of moving objects by SAR images, comprising the steps of:
- generating a pulse-repetition frequency signal starting from a radar signal;
- and
- generating a sequence of SAR images starting from the pulse-repetition frequency signal;
- the step of generating a sequence of SAR images comprises generating low azimuth resolution SAR images by means of coherent integration of the pulse-repetition frequency signal for a sub-aperture time shorter than an aperture time;
- generating difference images through point-to-point difference between subsequent low azimuth resolution SAR images;
- recognizing patterns associated with moving objects in the difference images;
- identifying moving-object patterns defined by waveforms comprising a first region, where values of the waveform have a first negative or positive sign, and a second region, where values of the waveform in the second region have a second sign opposite to the first sign, and wherein pre-determined morphological characteristics of the first region and of the second region are the same, except for a pre-determined tolerance;
- and
- discriminating moving-object patterns from image components, which are not part of any moving-object pattern, in the difference images.
An apparatus for detection of moving objects by SAR images comprising:
- a radar transceiver device;
- and
- a pre-processing line, for generating a pulse-repetition frequency signal starting from the radar signal;
- the pre-processing line comprises:
- a sub-aperture generator, configured for generating a sequence of low azimuth resolution SAR images by coherent integration of the pulse-repetition frequency signal for a sub-aperture time shorter than an aperture time;
- an image-difference module, for generating difference images through point-to-point difference between consecutive low azimuth resolution SAR images;
- a pattern-recognition module for recognizing patterns associated to moving objects in the difference images and wherein the patterns are defined by waveforms, each comprising a first region, where values of the waveform have a first negative or positive sign, and a second region, where values of the waveform have a second sign opposite to the first sign, and wherein pre-determined morphological characteristics of the first region and of the second region are the same, except for a pre-determined tolerance;
- a module configured to identify patterns associated with moving objects in the difference images;
- and
- a discrimination module configured for discriminating moving-object patterns from image components which are not part of any moving-object pattern, in the difference images.
Dependencies are inferred from the claim text.