INTRUSION DETECTION APPARATUS

• US 3,811,010 A
• Filed: 08/16/1972
• Issued: 05/14/1974
• Est. Priority Date: 08/16/1972
• Status: Expired due to Term

• Current Assignee: David T. Long
• Original Assignee: David T. Long
• Inventors: Long, David T.
• Primary Examiner(s): Britton, Howard W.
• Application Number:
  US05/281,080
• Time in Patent Office: 636 Days
• Field of Search: 178/6.5,6.8,DIG.38
• US Class Current: 348/154
• CPC Class Codes: G08B 13/19602 Image analysis to detect motion of the intruder, e.g. by frame subtraction
• CPC Class Codes: G08B 13/19634 Electrical details of the system, e.g. component blocks for carrying out specific functions
• CPC Class Codes: G08B 13/19641 Multiple cameras having overlapping views on a single scene

Abstract

Intrusion detection apparatus employing two spaced-apart TV cameras having lines of observation which intersect to form a three dimensional monitored locale of interest and a TV monitor having a display tube and connected to respond to output signals from said TV cameras. The cameras and monitors being synchronized to identify the presence and location of an intruder object in said locale of interest. In another aspect the invention comparator-adder analyzing circuitry is provided between the cameras and monitor such that the monitor is actuated only when the video from both cameras is identical at a given instant. Assuming each camera is directed to observe a different background and that the focus is adjusted to substantially eliminate background signals, then only signals from the intruder object are observed and it is observed only in the monitored locale.

Claims

1. In apparatus for detecting the intrusion of an object in a locale of interest, the improvement comprising:

a. two spaced apart TV cameras positioned for lines of observation which intersect and monitor a common empty three dimensional locale of interest having a mid-depth portion between adjacent monitored zones, b. a TV monitor having a display tube and connected to respond tO output signals from said TV cameras upon the intrusion of said object, c. said TV cameras having means for synchronization with themselves and with said monitor to provide a coincidence of said object in time and location on the tube of said monitor when a mid-depth portion of said locale of interest is invaded by said object, and otherwise to show double images each approaching the other as said object approaches said mid-depth portion of said locale and double images moving farther apart as said object moves away from said mid-depth portion of said locale whereby said object can be accurately located for destruction.

2. Apparatus according to claim 1 a. the spacing of said TV cameras being adjusted in relation to the rate of TV scan and to the speed of said intrusion object to provide a locale of interest of sufficient depth such that the intrusion object will be traveling through the depth of said locale of interest long enough for said television cameras to scan the entire locale of interest thereby identifying said object while it is passing through said locale of interest.

3. Apparatus according to claim 1 including:

a. means for modifying the display of said object on said screen to distinguish between object displays derived respectively from said cameras to thereby aid in tracing the object movement to and through said monitored locale.

4. Apparatus according to claim 3 wherein:

a. said displayed object modifying means comprises the provision of separate color elements in said monitor tube such that said objects derived from said separate cameras will appear in different colors until the point of coincidence is attained and will then appear as a third color.

5. Apparatus according to claim 1 including:

a. comparator-adder analyzing circuitry connected to pass a composite signal from said cameras to said monitor only when the camera output signals are coincident in time to provide for displaying said object on said monitor in the time and position corresponding only to the entry of said object in said mid-depth portion of said locale of interest.

6. Apparatus according to claim 5, a. said comparator-adder analyzing circuitry comprising an AND gate for receiving said camera output signals and passing as an output said composite signal.

7. Apparatus according to claim 6, a. said analyzing circuitry also including amplifier means and diode means connected as clipper circuits for passing said camera output signals to eliminate the background noise and allow to pass only the stronger signal derived from an intrusion object.

8. Apparatus according to claim 6, a. said analyzing circuitry including pulse width adjuster means to develop two overlapping pulses and present to said AND gate the appearance of two pulses of identical time as may be desired by the depth of the monitored locale in relation to the scan rate of said cameras.