초록 ▼

Methods and apparatus for detecting objects are disclosed. In one embodiment of the invention, a person entering a secured or "Safe Zone.TM." is illuminated with low-power polarized radio waves. Differently polarized waves which are reflected back from the person are collected and measured. In a pre

Methods and apparatus for detecting objects are disclosed. In one embodiment of the invention, a person entering a secured or "Safe Zone.TM." 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 of the invention, concealed weapons are detected by calculating the difference of a pair of differences between levels of different polarized reflected energy in the time domain, and by using signal processing methods and apparatus to improve the reliability of the detection process. Alternative embodiments of the invention may be used to detect a wide variety of objects other than concealed firearms. The invention may be used for inventory control or to thwart shoplifting.

대표청구항 ▼

[ What is claimed is:] [11.]11. An apparatus for detecting an object, said apparatus comprising:means for illuminating a target person with horizontally polarized radiation;means for collecting radiation reflected from said target which has a polarization which is the same as said radiation used to

[ What is claimed is:] [11.]11. An apparatus for detecting an object, said apparatus comprising:means for illuminating a target person with horizontally polarized radiation;means for collecting radiation reflected from said target which has a polarization which is the same as said radiation used to illuminate said target;means for collecting radiation reflected from said target which has a polarization that is orthogonal to that of said radiation which is used to illuminate said target;means for calculating a difference between a collected radiation level of radiation reflected from said target which has a polarization that is orthogonal to that of said radiation which is used to illuminate said target and a predetermined average radiation level, which, if positive, indicates that a weapon is present; andmeans for calculating one or more differences between collected radiation levels and predetermined average radiation levels, which, if positive, indicates that there is a false alarm.