MOTION DETECTOR SYSTEM WHICH SAMPLES ONLY A PRESELECTED AREA

• US 3,603,729 A
• Filed: 03/13/1969
• Issued: 09/07/1971
• Est. Priority Date: 03/13/1969
• Status: Expired due to Term

• Current Assignee: Martin Sperber
• Original Assignee: Martin Sperber
• Inventors: Sperber, Martin
• Primary Examiner(s): Murray, Richard
• Assistant Examiner(s): Eckert, Jr., Richard K.
• Application Number:
  US04/807,039
• Time in Patent Office: 908 Days
• Field of Search: 178/6,6.8,DIG.3,DIG.21
• 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 13/19645 Multiple cameras, each having view on one of a plurality of scenes, e.g. multiple cameras for multi-room surveillance or for tracking an object by view hand-over
• CPC Class Codes: G08B 13/19691 Signalling events for better perception by user, e.g. indicating alarms by making display brighter, adding text, creating a sound
• CPC Class Codes: G08B 13/22 Electrical actuation

Abstract

A selected part of a television surveillance camera field is selected for motion detection by variable x-y selection circuits; each successive signal sweep of this sample area is alternately fed to one of a pair of capacitive memory circuits the output of which are supplied to a differential comparator circuit to detect changes in the signals between successive sweeps of the selected area, a change in signal producing an output from the differential comparator which activates an alarm.

Claims

1. A closed circuit television motion detector system, comprising:

a. a video camera, b. motion detector means connected to said camera for receiving the video signal from the camera and sampling a preselected sampling area, c. the motion detector means including positioning logic and counter circuitry referenced to the video signal synchronization pulses for permitting variance of size and change of location of the sampling area within the field of view of the video camera, d. the motion detector means also including comparison means for receiving signals from the sampling area in successive scans and comparing the successive signals, e. a television monitor connected to said motion detector means for receiving and displaying the entire field of view of the video signal, f. means for displaying on the TV monitor the preselected sampling area, and g. said motion detector means having an alarm circuit for signalling when the comparison means detects a change between successive scans of the sampling area.

2. The closed circuit motion detector system as set forth in claim 1 wherein:

a. said motion detector means includes automatic gain control circuitry to permit said motion detector to be connected to a camera and monitor system of varying energy level without requiring adjustment and to provide automatic correction of varying light levels within the total field of view of the camera.

3. The closed circuit television motion detector system as set forth in claim 1 wherein;

a. said motion detector means includes means for activating the alarm circuit when the video camera signal is interrupted.

4. The closed circuit television motion detector system as set forth in claim 1 wherein:

a. said motion detector means includes a plurality of electronic signal storage circuits for successively receiving said video signal scans of a sampling area.

5. The closed circuit television motion detector system as set forth in claim 1 wherein:

a. the means for displaying the sampling area on the monitor screen includes a video sample display brightness control means for providing a brightened sampling area display.

6. A plural channel closed circuit motion detector system, comprising:

a. a plurality of closed circuit television cameras, b. a motion detector unit connected to the output of each television camera and having a video output line and an alarm line, c. each motion detector unit including positioning logic and counter circuitry referenced to the video signal synchronization pulses for varying the size and location of the sampling area within the field of view of its corresponding video camera, d. a common automatic switching console to which the video output and the alarm lines of each of said motion detector units are connected, e. said console being connected to a television monitor, f. automatic circuitry within said console for connecting the video output of a given motion detector unit to the monitor when an alarm signal is received from that motion detector unit.

7. The plural channel closed circuit television system as set forth in claim 6 wherein:

a. said automatic switching console includes individual manual switch means for connecting the video output of any camera to said television monitor.

8. The plural channel closed circuit television system as set forth in claim 6 wherein:

a. said automatic switching console has an indicator panel with a plurality of lamps, one for each closed circuit television camera, which are lit and its corresponding video camera signal displayed on said television monitor when its motion detector unit transmits an alarm signal to said console.

9. A motion detector unit for use with a closed circuit television system, comprising:

a. receiving means for receiving a video camera output signal, b. signal isolation means for isolating the horizontal and vertical synchronization pulses from the video signal, c. control pulse generating means including logic and counter circuitry for receiving the horizontal and vertical synchronization pulses and emitting a control pulse, d. gate means connected to the output of the receiving means and to the control pulse means for passing the video signal therethrough subject to the control pulse received from the control pulse means, e. electrical storage means connected to the gate means for electrically receiving and storing the video signals passed through the gate means, d. electrical comparison means connected to the storage means for comparing successive video signals stored in the storage means, and e. means connected to the electrical comparison means for emitting a signal when there is more than a preselected change in successive video signals stored in the electrical storage means.

10. The motion detector unit as set forth in claim 9, wherein:

a. the electric storage means includes a capacitive storage circuit.

11. The motion detector unit as set forth in claim 10, wherein:

a. a constant current amplifier is connected between the gate means and the capacitive storage circuit.

12. A motion detector unit for use with a closed circuit television system, comprising:

a. a video camera sweep signal receiving means for receiving a television signal, and for transmitting it to a television receiver, b. a pair of matched electronic memory storage circuits connected to said signal receiving means, and to which successive identical sampling area video camera signals are alternately applied, c. separate gate means connected between each of the electronic memory storage circuits and the sweep signal receiving means and including positioning logic and counter circuits responsive to the horizontal and vertical synchronization pulses, each of which are alternately gated for selecting and passing to their respective electronic memory storage circuits any desired portion of the video signal representing a variable size and movable sampling area of the field of view of the camera, d. an electronic comparator network connected to said electronic memory storage circuits to detect a difference in successive video camera sweep signals, e. an alarm circuit connected to said electronic comparator network for sending an alarm signal when the difference in successive video camera sweep signals is detected.

13. The motion detector unit of claim 12 wherein:

a. the gate means includes frequency sampling control means for decreasing the number of frames of the video signal scanned, for permitting measurement of different rate movements.

14. The motion detector unit as set forth in claim 12 wherein:

a. automatic gain control circuitry is connected to the video camera signal receiving means and to the output of the electronic comparator network for control of the output signal level transmitted to the television receiver and the matched electronic memory storage circuits, b. the automatic gain control circuit includes a field-effect transistor, the gate of which is connected to the electronic comparator network.

15. The motion detector unit of claim 12 wherein:

a. a vertical monostable delay circuIt is activated by the vertical synchronization pulse to define the upper horizontal line of the sampling area, b. a monostable circuit is activated by the horizontal synchronization pulse to determine the left-hand margin of the sampling area.

16. A closed circuit television motion detector system, comprising:

a. a television camera for producing a video signal of the field being scanned, b. a motion detector unit connected to said television camera for receiving and comparing selected successive video cans of a desired sampling area of said field, c. a television monitor for displaying the field of said television camera, d. said motion detector unit having means to connect said video television camera and said television monitor. e. gate means controlled by pulse generating means operated by the horizontal and vertical synchronization pulses of said television camera for passing only the video signals from a desired sampling area to said motion detector unit, and f. video display control means connected to said transmitting means and controlled by said gate means for sending a video signal to said television receiver resulting in a brightened display area on the television receiver screen. 17 A motion detector unit for use with a closed circuit television system, comprising;

a. means for receiving successive identical sampling area video camera signals and for separating the video signals from the horizontal and vertical synchronization pulses, b. a pair of individual matched electronic memory storage units to which the successive video signals are alternately applied, c. said memory unit including a transistor control gate connected to said signal receiving means for passing the video signal, d. a constant current transistor amplifier connected to said transistor gate, e. a large storage capacitor being charged by said constant current amplifier, f. a pair of matched transistor amplifiers having a high input impedance, g. the base of one transistor being connected with the constant current amplifier output and the storage capacitor of the first memory unit, and the second transistor being connected in parallel with the constant current amplifier output and the storage capacitor of the second memory unit, h. said matched transistors being connected to provide a differential amplifier circuit, i. a reset gate circuit connected to each of said storage capacitors to provide a means for discharging said capacitors, j. control pulse means activated by the horizontal and vertical synchronization signals of said video camera to alternately activate the control gates of said pair of memory storage units for selected successive frames of video signals, k. said control pulse means also acting to control said reset gate circuits to provide for alternate discharge of said capacitor therethrough following differential comparison of the capacitive charges at the end of each selected video camera sweep, l. output alarm means connected to said differential amplifier circuit to give an alarm signal when there is a difference in charge on said storage capacitors.

18. The motion detector unit for use with a closed circuit television system as set forth in claim 17 wherein:

a. said motion detector unit includes a filed effect transistor circuit in circuit therewith for supplying automatic gain control for the unit and, b. said output alarm circuit includes circuitry to activate the alarm in the event of failure of the video signal.