Signal processing for object detection system
AssigneeSafe Zone Systems, Inc.
InventorJerry Hausner
Life of this patent
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Abstract
Methods and apparatus for detecting objects. In one embodiment, a person entering a secured or “Safe Zone™” is illuminated with low-power polarized radio waves. Differently polarized waves which are reflected back from the person are collected and measured. In a preferred embodiment, concealed weapons are detected by calculating the difference of a pair of differences (Delta A and B) of different polarized reflected energy (upper and lower curves in the two graphs) in the time domain, and by using signal processing methods and apparatus to improve the reliability of the detection process.
Claims20
A method of detecting an object comprising the steps of:
- illuminating a target with polarized radiation over a band of frequencies;
- collecting first radiation reflected from said target which has a polarization which is the same as the radiation used to Illuminate said target;
- and
- collecting second radiation reflected from said target which is oppositely polarized to that of said radiation which is used to illuminate said target;
- and
- employing a weighted plurality of criteria of the collected radiation over the band of frequencies converted to a time domain to determine automatically whether the object is present or not.
An apparatus for detecting an object comprising:
- means for illuminating a target with polarized radiation over a band of frequencies;
- means for collecting first radiation reflected from said target which has a polarization which is the same as the radiation used to illuminate said target;
- and
- means for collecting second radiation reflected from said target which is oppositely polarized to that of said radiation which is used to illuminate said target;
- and
- means for employing a weighted plurality of criteria of the collected radiation over the band of frequencies converted to a time domain to determine automatically whether the object is present or not.
Dependencies are inferred from the claim text.