GB2328578A

GB2328578A - Automatic reset of remote video surveillance system

Info

Publication number: GB2328578A
Application number: GB9717714A
Authority: GB
Inventors: Kenneth Neville Burgin
Original assignee: MOTION MEDIA TECHN Ltd
Current assignee: MOTION MEDIA TECHN Ltd
Priority date: 1997-08-22
Filing date: 1997-08-22
Publication date: 1999-02-24
Also published as: GB9717714D0

Abstract

Remote video surveillance equipment includes one or more processors, particularly for image compression, having a facility for detecting when the system ceases operating correctly due to hardware or software fault and means to reset the system in the event of such detection. The detection facility may be a timer reset register, written to periodically either by a process (Process1) at intervals less than the timeout period or by a process which periodically polls other processes and only writes to the timer reset register if all processes respond.

Description

AUTOMATIC RESET OF REMOTE VIDEO SURVEILLANCE SYSTEM AFTER FAILU RE.

This invention relates to a remote video surveillance system using video compression and using the telephone network, or a narrow band communications system, for communicating pictures to a monitoring station.

The electronics used in a normal CCTV system, although expensive, is relatively simple and straighfforward. In any event, the monitoring station tends to be local and problems can often be solved by sending personnel to the site.

The electronics and software associated with image compression techniques, on the other hand, is well known to be compiex and therefore prone to 'crash', i.e.

enter a locked-up state where processing stops. If this happens in a remote surveillance systems, there is a high probability that the pictures will cease to be transmitted and that the control centre will be unable to unlock the system and return it to normal operation.

Under such conditions, the only option would be to send an engineer to the site and reset the system manually, usually by switching off the power and switching it back on.

According to the present invention there is provided a mechanism in remote surveillance equipment to periodically perform a self test and to automatically perform a system reset when the equipment ceases to operate correctly because one or more processor has stopped processing or because one or more of the processes running on the processor(s) has stopped running correctly or because some other fault has been detected which might be rectified by resetting the system.

In any remote surveillance equipment a call may be handled by a single process or by multiple processes, which may be running on one or more processors. A remote surveillance subsystem may also dependent on a host computer system in order to function correctly.

If any of the processes required to send compressed pictures or any other information to the monitoring station or which control the remote system itself stops running correctly for any reason, the remote system detects this situation, terminates any call running at the time and the equipment is reset to a known and useful state.

Two specific embodiments of the invention will now be described by way of two related examples with reference to the accompanying drawing.

Referring to the drawing, a processor 11 is connected to the telephone line 12.

The processor sits between the telephone line and the rest of the security system, which comprises the camera 13 and an intruder detection system 14.

Communication with the monitoring station can therefore proceed only if the processor is processing.

A hardware timer 15 is also connected to the processor which can update the hardware timer's registers.

The hardware timer is started and re-started by writing to its TimerReset register.

That is, whenever the TimerReset register is written to, the timer starts counting.

When the timer reaches a pre-set Timeout value it resets the processor, cutting off any call that was in progress, and causes the system to reboot itself into a predefined state where normal operation can be resumed.

In Example 1, the video and control communications are handled by a single process, Process 1, running on the processor.

When the system is started, Process writes to the TimerReset register, starting the timer. As well as handling the video and any other communications to the control centre, Processl also writes periodically to the timer's TimerReset register, at intervals which are shorter than the timer's Timeout value. The timer is thus prevented from reaching its Timeout and re-setting the system.

There are several reasons which could prevent Process from operating the within the system as it should: an error in the code might cause it to stop or enter an infinite loop; the process might be terminated for some reason; the processor itself might stop processing. In each case Process will also be unable to write to the TimerReset register. The timer will therefore reach its Timeout and reset the system, thereby causing the system to restart.

In Example 2 the video and control communications are handled by several processes running on the processor. One of the processes, Process 1, is responsible for periodically polling the other processes to check that they are running correctly.

The function of one of the processes is to check that various parts of the system's hardware are operating correctly.

When the system is started, Processl writes to the TimerReset register, starting the timer. As long as all the other processes respond to its polls, Processl writes periodically to the timer's TimerReset register at intervals which are shorter than the timer's Timeout value. The timer is thus prevented from reaching its Timeout and re-setting the system.

If any of the processes fails to respond to a poll, Process does not write to the timer's TimerReset register. If Process itself stops running correctly for any reason it will also be unable to write to the TimerReset register, as in Example 1.

Therefore if any process is not running correctly the timer will reach its Timeout and reset the system, thereby causing the system to restart.

Claims

1. A mechanism in remote video surveillance equipment to reset itself automatically when the equipment ceases to operate correctly because one or more processors have stopped processing or one or more of the processes running on the processor(s) has stopped running correctly.

2. A mechanism as claimed in Claim 1 wherein the equipment is returned to a predefined useable state on the expiration of a timer, which is repeatedly reset whilst the equipment is operating correctly but ceases to be reset when one or more processors stops processing or one or more processes stops running correctly.

3. A mechanism as claimed in Claim 1 wherein a correctly running process causes the equipment to reset due to a hardware fault being detected.

4. A mechanism as claimed in Claim 2 wherein the timer is implemented in hardware.

5. A mechanism as claimed in Claim 2 wherein the timer is implemented in software.

6. A mechanism as claimed in any of Claims 1, 2, 3 or 4, where the equipment is self-contained.

7. A mechanism as claimed in any of Claims 1, 2, 3,4 or 5, where the remote video surveillance equipment is a subsystem in a host system.

8. A mechanism as claimed in Claim 7 where the remote video surveillance equipment relies upon the host system's processor(s) and where the telephone call is also terminated if the host system's processor(s) cease processing.

9. A mechanism as claimed in Claim 7 or Claim 8 where the host system contains more than one remote video surveillance subsystem.

10. A mechanism substantially as described herein with reference to the accompanying drawing.