Surveillance method and apparatus

• US 4,408,224 A
• Filed: 04/22/1981
• Issued: 10/04/1983
• Est. Priority Date: 05/09/1980
• Status: Expired due to Fees

• Current Assignee: Hajime Industries Limited Kudan Sanzen BLDG
• Original Assignee: Hajime Industries Limited
• Inventors: Yoshida, Hajime
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Coles, Edward L.
• Application Number:
  US06/256,653
• Time in Patent Office: 895 Days
• Field of Search: 358/105, 358/108, 358/113, 250/342, 250/338, 280/347
• US Class Current: 348/155
• CPC Class Codes: G08B 13/19602 Image analysis to detect motion of the intruder, e.g. by frame subtraction
• CPC Class Codes: G08B 13/19676 Temporary storage, e.g. cyclic memory, buffer storage on pre-alarm

Abstract

A place scenery is surveilled by a video camera. The image signal from the video camera is converted to data, the data is stored in a memory as a current data and then compared with previous data which was prepared and stored in another memory in a previous surveillance period. The current and previous data is compared and an alarm signal generated when there is a difference between both data. Thereafter the previous data is erased and replaced by the current data in the memory and stored until the next image data is derived from the video camera. The operation is repeated at predetermined time intervals.

Claims

1. A place scenery surveillance apparatus comprising:

(a) a video camera picking up a place scenery to be surveyed and producing a video signal;

(b) a data conversion means for converting the video signal responding to the place scenery from said video camera into data signal;

(c) a first memory means for memorizing said data signal from said data conversion means as a current data signal;

(d) a second memory means for memorizing a data signal from said first memory means as a previous data signal provided during a previous surveillance;

(e) a comparison means for comparing said current data signal stored in said first memory means with said previous data signal stored in said second memory means;

(f) an erasing means for erasing the previous data signal memorized in said second memory means;

(g) first, second and third switching means which are respectively inserted between said first and second memory means and said comparison means, said erasing means and said second memory means as well as between said first memory means and said second memory means;

(h) a control means for controlling ON and OFF of said first, second and third switching means in time sharing manner such that said first switching means is made ON at first to supply said current data signal and previous data signal to said comparison means, after said comparison being finished said second switching means being made ON to erase said previous data signal memorized in said second memory means, and then said third switching means being made ON to supply said current data signal to said second memory means to be memorized as a new previous data signal for next surveillance; and

(i) an alarm generating means for generating an alarm upon receiving an output that is generated by said comparison means.

2. A place scenery surveillance apparatus as claimed in claim 1, in which said control means includes an intermittent time signal generator and a signal distribution section, said intermittent time signal generator producing a pulse signal with a predetermined time interval, and said signal distribution section receiving said pulse signal and then producing consective pulse signals which are respectively supplied to said first third switch is to control ON and OFF of them.

3. A place scenery surveillance apparatus as claimed in claim 2, in which said consecutive pulses are all produced within a time period between adjacent pulse signals from said intermittent time signal generator or within said predetermined time interval.