NCJ Number
56190
Date Published
1977
Length
8 pages
Annotation
A DESCRIPTION IS PROVIDED OF A SELF-ALARMING X-RAY SYSTEM THAT DETECTS CONCEALED WEAPONS IN LUGGAGE OR PACKAGES, BASED ON A COMPARISON OF VIEWED OBJECT PATTERNS WITH A SET OF PREDETERMINED PROFILES.
Abstract
ALTHOUGH THE SYSTEM ALLOWS FOR TELEVISION MONITOR VIEWING, ITS CHIEF FUNCTION IS TO AUTOMATICALLY IDENTIFY WEAPONS BY THEIR SHAPE. THE IMAGING SYSTEM UTILIZES 256 DISCRETE PHOTOTRANSISTORS ORGANIZED IN A LINEAR ARRAY APPROXIMATELY 65 CENTIMETERS LONG. THE PHOTOTRANSISTORS ARE IN CONTACT WITH A FLOURESCENT SCREEN WHICH EMITS LIGHT WHEN ENERGIZED WITH X-RAY. THIS ARRANGEMENT PRECLUDES THE NEED FOR OPTICS, MIRROR, LENS, IMAGE AMPLIFIER, AND CAMERA, THEREBY ELIMINATING NUMEROUS COMPONENTS AND ADJUSTMENTS WHICH MAY AFFECT SYSTEM RELIABILITY. THE DETECTOR ARRAY OUTPUT IS SCANNED BY DIGITAL CIRCUITS AND FED TO A MICROPROCESSOR WHICH PROCESSES THE DATA AND ASSIGNS AND OUTPUTS A DIGITAL NUMBER CORRESPONDING TO THE DIFFERENTIAL ABSORPTION OF THE OBJECT IN THE X-RAY FIELD. THE SYSTEM DETECTS OBJECTS ACCORDING TO THEIR DENSITY, ORIENTATION WITH RESPECT TO THE SOURCE GEOMETRY, AND AREA. THE MAJOR FUNCTION OF THE ALARM SYSTEM IS TO DETERMINE IF THE OBJECT'S DIMENSION IS GREATER THAN A PREDETERMINED DIMENSION; IF SO, THEN AN ALARM IS AUTOMATICALLY SOUNDED. INITIAL FIELD TESTS INDICATE THAT OFFENSIVE HAND WEAPONS IN A LUGGAGE CAN BE VISUALLY DETECTED AND CAUSE THE SYSTEM ALARM CIRCUITRY TO ACTIVATE ON A RELIABLE BASIS. THE WIDE LATERAL RANGE AFFORDED TO MATERIALS DETECTION ALSO ALLOWS FOR THE EFFECTIVE DETECTION OF CONCEALED EXPLOSIVE DEVICES, ALTHOUGH IMPROVED OPERATOR AWARENESS WOULD REDUCE ERRORS. GRAPHIC DATA ARE PROVIDED, ALONG WITH REFERENCES. (AUTHOR ABSTRACT MODIFIED--KBL)