Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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VIDEO VERIFICATION SYSTEM AND METHOD FOR
CENTRAL STATION ALARM MONITORING
TECHNICAL FIELD
The present invention relates to alarm monitoring, and in particular to a
method and system for passing images to a central alarm station for visual
verification
of an alarm condition.
BACKGROUND INFORMATION
Typical remotely monitored alarm systems include one or more sensors at the
monitored location. These sensors directly or indirectly send alarm
indications to a
central monitoring station where monitoring personnel takes some action based
on the
nature of the alarm. Such alarm indications are typically sent via modem using
a
standard low bandwidth telephone (POTS) line or low bandwidth cellular
telephone
line. However, these sensors and the entire system are susceptible to false
alarms.
False alanns lead to added expenses incurred with attempts to contact the
location
personnel, homeowner, etc., as well as the unnecessary dispatching of law
enforcement or security personnel. In addition to added expenses, false alarms
also
decrease the efficiency of monitoring station personnel because the personnel
is
wasting tixne chasing a false alarm when they could be dealing with real
alarms or
other monitoring activities. A result is that the servicing of a real alarm
may be
delayed.
An approach to address the false alarm problem is to include a video camera to
capture video associated with alarm events. These approaches typically use
real time
motion video that is either always being transmitted to the central monitoring
station
or is transmitted based on the occurrence of a sensor trigger. However, while
a POTS
line (or cellular telephone line) may be sufficient for conveying the trigger
of an alarm
to a central monitoring station, POTS lines do not provide sufficient
bandwidth to
allow a usable video signal to be transmitted thereon. The resultant low
resolution
images that can be transmitted using POTS lines are difficult to evaluate to
discern
whether or not an unauthorized entry to the monitored location has occurred.
Further,
use of higher speed transmission lines and technology adds costs and
complicates the
installation. Put simply, the use of video cameras to capture images for
transmission
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to a central monitoring station is not practical without some way to allow for
low
resolution iinage evaluation.
It is therefore desirable to have a method and system that allows low
resolution images to be transmitted to a central monitoring station and
processed for
display in a manner that allows an operator to quickly and easily discern
whether the
alarm is a false alarm or whether the alarm is real and requires additional
processing
such as the dispatch of law enforcement personnel.
SUMMARY OF THE INVENTION
The present invention addresses the deficiencies of the art in respect to
providing a visual indication to monitoring station personnel in the form of
one or
more images that quickly allows the operator to determine whether or not the
alarm
trigger is one which requires further attention. The present invention
addresses the
deficiencies by providing a series of low resolution images taken at period
intervals in
a manner that allows an operator to discern the differences from one image to
the next
to determine the presence of unauthorized persons and/or the absence of
personnel or
objects. In addition, the present invention can process the series of images
to create
an image that shows the differences between one or more of the images. This
arrangement allows the operator's attention to be focused on the potentially
relevant
changes rather than have to study each image to determine if there is a
difference and
what that difference is.
In accordance with one aspect, the present invention provides a method for
verifying an alarm system event in which image data corresponding to a
plurality of
images associated with the event is transmitted. The image data corresponding
to the
plurality of images is processed to create one or more processed images in
which the
one or more processed images are arranged to allow an operator to visually
observe
changes in the plurality of images. The one or more processed images are
displayed.
In accordance with another aspect, the present invention provides a central
monitoring station usiiig image data corresponding to a plurality of images
associated
with an alarin event to visually verify the alarnn event in wliich the central
monitoring
station has a central processing unit and a display. The central processing
unit
processes the image data corresponding to the plurality of images to create
one or
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more processed images. The one or more processed images are arranged to allow
an
operator to visually observe changes in the plurality of images. The display
displays
the one or more processed images for visual verification by the operator.
In accordance with yet another aspect, the present invention provides a system
for verifying an alarm system event in which the system has a camera, an
alarin panel
and a central monitoring station. The camera captures a plurality of images
associated
with the event. The alarm panel transmits image data corresponding to the
plurality
of images associated with the event. The central monitoring station has a
central
processing unit and a display. The central processing unit processes the image
data
corresponding to the plurality of images to create one or more processed
images. The
one or more processed images are arranged to allow an operator to visually
observe
changes in the plurality of images. The display displays the one or more
processed
images for visual verification by the operator.
Additional aspects of the invention will be set forth in part in the
description
which follows, and in part will be obvious from the description, or may be
learned by
practice of the invention. The aspects of the invention will be realized and
attained by
means of the elements and combinations particularly pointed out in the
appended
claims. It is to be understood that both the foregoing general description and
the
following detailed description are exemplary and explanatory only and are not
restrictive of the invention, as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute part of
this specification, illustrate embodiments of the invention and together with
the
description, serve to explain the principles of the invention. The
einbodiments
illustrated herein are presently preferred, it being understood, however, that
the
invention is not limited to the precise arrangements and instrumentalities
shown,
wherein:
FIG. 1 is a diagram of a systein constructed in accordance with the principles
of
the present invention;
FIG. 2 is a diagrain of an exemplary image processing procedure of the present
invention;
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FIGS. 3A-3C are diagrams showing exemplary images and a resultant difference
image based on image processing procedures of the present invention;
FIG. 4 is a diagrain of a second exemplary iinage processing procedure of the
present invention;
FIG. 5 is a diagram of a third exemplary image processing procedure of the
present invention;
FIG. 6 is a diagram of an exeinplary image processing procedure of the present
invention using a tiine delay between image acquisitions; and
FIG. 7 is a diagram of an exenzplary image processing procedure of the present
invention using a trigger and a time delay between image acquisitions.
DETAILED DESCRIPTION
The present invention advantageously provides a method and systemm that
allows an operator at a remote monitoring station to review an image or series
of
images to quickly distinguish between a false alarnl and a real alarm. The
image or
images presented to the operator can be transferred from the monitored site to
the
central monitoring station using existing technology such as POTS lines. The
images
can be in the form of a series of snapshots once a triggering event has
occurred or be
in the form of a single composite image showing the difference between two or
more
images.
Referring now to the drawing figures in which like reference designators refer
to like elements there is shown in FIG. 1 a system constructed in accordance
with the
principles of the present invention and designated generally as "10". System
10
includes monitored location 12 and central monitoring station 14,
communicating
with one another via communication network 16. Communication network can be
any cornmunication network capable of transporting image data from monitored
location 12 and central monitoring station 14, including but not limited to a
POTS
(dial-up networlc), wireless cellular telephone network, Transmission Control
Protocol/hiternet Protocol ("TCP/IP") network and the like. In the case of the
POTS
dial-up network, the communication line connectiiig monitored location 12 with
the
eleinents of cominunication network 16 can be an analog dial-up telephone
line,
dedicated analog telephone line and the like.
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Central monitoring station 14 is typically remotely located from monitored
location 12 but need not be. Central moni.toring station 14 can be coupled to
communication network 16 in a similar manner as monitored location 12. Of
note, it
is not required that central monitoring station 14 be coupled to communication
5 network 16 in the exact same manner as monitored location 12. For example,
while
monitored location 12 may be coupled to communication network 16 via a dial-up
analog teleplione line, the image data carried to communication network 16 on
this
analog line can be supplied to central monitoring station 14 via a digital
communication link using a protocol such as TCP/IP. In that regard,
communication
network 16 includes the components needed to recover the image data from the
analog line and transmit the same image data to central monitoring station 14
on a
digital communication line.
Central monitoring station 14 includes hardware and software arranged to
perforin the functions of the present invention described herein. For example,
central
inonitoring station 14 includes a display, central processing unit, volatile
and non-
volatile storage, input/output devices and a network interface for coupling
central
monitoring station 14 to communication network 16. The network interface can
be a
wired or wireless interface. Central monitoring station 14 can be any suitable
computing device such as a personal computer, a mini or a mainframe coinputer,
a
personal digital assistant ("PDA"), etc. running a suitable operating system
as may be
known in the art. Although a single central monitoring station 14 is shown,
such is
done merely for the ease of explanation of the present invention. It is
understood that
multiple central monitoring stations 14 can be provided at a reinote location
in a more
complex arrangement under which a pool of operators are used to monitor alarms
from multiple monitored locations 12.
In operation, as is explained below in more detail, image data corresponding
to
an image or series of images is transmitted from monitored location 12 to
central
monitoring station 14 via coinrnunication network 16 upon the occurrence of a
triggering event. Central monitoring station 14 processes the iinage data and
presents
one or more processed images on its display screen to the operator. This image
or
ilnages allows the operator to assess whether or not the triggering event is a
real
alarm.
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Monitored location 12 includes one more cameras 18 and sensors 20 wired or
wirelessly communicating with panel 22. Sensors 20 can be any sensors capable
of
triggering an alarm including but not limited to wired and wireless motion
sensors,
heat sensors, infra-red sensors, glass break sensors, microwave sensors,
acoustic
sensors, ultrasonic sensors, sonic sound sensors, photoelectric sensors,
pressure
mats/sensors and magnetic sensors. Cameras 18 are arranged to communicate with
panel 22 using wired or wireless communications. Camera 18 can be any cameras
suitable for capturing images for subsequent transmission to central alarm
monitoring
station 14. Suitable cameras 18 include but are not limited to still or motion
cameras
that capture the images in black and white and/or color. Cameras 18 can be
fixedly
mounted or can be of the pan/tilt/zoom type. Cameras 18 can be arranged to
provide
continuous video or still image feeds to pane122 or can be arranged to capture
images
when a sensor 20 is triggered. Cameras 18 can provide digital image data to
panel 22
or can provide analog image data to panel 22. In the latter case, electronics
in panel
22 digitize the analog image data for subsequent transmission to central
monitoring
station 14.
Pane122 includes hardware and/or software elements for capturing digital
image data from cameras 18 or, as noted above, digitizing analog image data
received
from cameras 18. Panel 22 also includes hardware and/or software elements for
receiving trigger indications from sensors 20. Optionally, pane122 can be
arranged to
trigger one or more cameras 18 to capture image data based on one or more
predeterrnined criteria such as trigger indications from sensors 20, periodic
image
capture regardless of trigger event, etc. Hardware and/or software for
communicating
with cominunication network 16 are also included within pane122. For exainple,
panel 22 can include an analog inodem for dial-up communications, a DSL modein
for digital coinmunications, a cellular phone transmitter for wireless
cellular
communications, etc.
In operation, pane122 facilitates cominunication from monitored location 12
to central monitoring station 14 so that image data captured by cameras 18 can
be
processed and presented on the display of central monitoring station 14 for
analysis
and action by the corresponding operator.
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As noted above, the image data sent to central monitoring station 14 can be
based on a triggering alarm event or simply periodic images transmitted. For
example, the images can be periodically captured in a continuous loop so that
a pre-
alarm image is captured. Regardless, it is conteinplated that image data for a
series of
images is transmitted to central monitoring station 14 for display or
subsequent
processing. In the fon-ner case, the series of images can be provided within a
single
display window, such as in the fonn of thumbnail images, so that the operator
can
discern whether or not the images depict activity that warrants additional
action at the
monitored location, such as a visit by law enforcement or security personnel.
In the
latter case, as is described below in detail, central monitoring station 14 or
some other
processing device (not shown) processes the image to further siinplify
analysis by the
operator.
Examples of acquiring image data and processing the image data to create
display images for visual verification of an alarm event are described. A
first
exemplary method of creating display images is described with reference to
FIGS. 1
and 2. Upon occurrence of an alarm event, image data corresponding to images
24a-
24e are transmitted from panel 22 to central monitoring station 14. Monitoring
station
14 processes the images by subtracting the image data for each image from the
iinage
data for the previous image to create four sub-images 26a-26d. The resultant
processed images 26a-26d are displayed on monitoring station 14 so that the
operator
can determine the absence or presence of a condition which would necessitate
further
action. In case of the method shown in FIG. 2, each sub-image is the
difference
between an image acquired by camera 18 and the previous image captured by that
camera. Presenting the four processed images 26a-26d to an operator quickly
allows
the operator to determine whether there is something in a captured image that
was not
there in, or is inissing from, the previous acquired image.
For example, FIGS. 3A, 3B and 3C show three examples of two consecutive
acquired images and a processed image such as might occur with respect to the
method shown in FIG. 2 or any of the other exemplary methods described herein.
FIG. 3A shows fraine 28 in which there is human 30, table 32 and box 34. Such
an
image might correspond, for example, to image 24a in FIG. 2. The next captured
image, shown as frame 36 in FIG. 3B shows only the presence of table 32 and
object
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38. In accordance with one embodiment, frames 28 and 36 can be presented to
the
operator on monitoring station 14 to allow the operator to visually determine
that
human 30 is not present in frame 36 and that box 34 is missing. This may be
significant, requiring that the operator alert security or law enforcement
personnel.
Frame 36 might also correspond to image 24b in FIG. 2. In such a case,
monitoring
station 14 would process the image data corresponding to images 24a and 24b,
shown
as fraines 28 and 36 in FIGS. 3A and 3B, respectively, to derive processed
frame 40
shown in FIG. 3C, corresponding to processed image 26a in FIG. 2. In such a
case,
the operator would be provided with a processed image showing human 30, box 34
and object 38.
Of note, it is recognized that when subtracting image data for which an image
is present in a subsequent fraine but is not in the prior frame, such as
object 38 in FIG.
3B, a negative value may result such that the resultant data is not
displayable as an
image because the corresponding data represents a value below the black value.
However, the data for the entire processed image can be scaled so that all
data can be
presented visibly, or negative values for processed image data displayed as
their
absolute value. For example, if the processed images are to be displayed on
central
monitoring station 14 in gray scale in which each pixel is represented b a
value of 0-
255, the data corresponding to the processed image can be scaled so that all
pixels fall
within this range or such that a pixel processed to have a negative value
because it
corresponds to an object that is present in or missing from a subsequent frame
can be
presented as an absolute value. A more detailed example is provided below. In
addition, it is noted that the image data or the resultant processed irnages
can be
further processed to reduce noise present in the image. Of note, the scaling,
absolute
value and noise reduction processes are applicable to any of the image
processing
methods discussed and described herein, and are not relegated only to the
method
described in FIG. 2.
Another exemplary method of processing image data and presenting a
processed image to an operator using central monitoring station 14 is
described with
reference to FIG. 4. Assunle that the occurrence of an alann event which
results in
the capture of images 24a-24e. In accordance with this method, processed
images
26a-26d are further processed to create a single processed image 42
representing the
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summation of data corresponding to images 26a-26d. The resultant composite
processed image 42 is displayed to the operator on central monitoring station
14. This
arrangement advantageously allows a single image to be presented on central
monitoring stationl4 to quickly allow the operator to determiile the presence
or
absence of a human, object, etc., so that the operator can make a decision as
to
whether security or law enforcement personnel should be called to the
monitored
location. For example, although not shown, a human walking across the room
would
be depicted in processed image 42 as showing the human at different locations
in the
image, thereby allowing an operator to quickly determine that the human was
moving
through the monitored location. Based on this situation, the operator can
quickly
visualize this situation and make a determination as to what further action
might be
necessary.
Still another exainple of a method for creating a single processed image for
display on monitoring station 14 based on captured images is described with
reference
to FIG. 5. In this method, images 24a-24e are processed such that iinage 24a
serves
as the starting point, and the data for each subsequent iinage is subtracted
from the
image data corresponding to image 24a and results then suinined together to
form the
single image. For example, iinage data corresponding to iinages 24a-24e are
transmitted by panel 22 to monitoring station 14 and processed to create four
sub-
images 44a-44d in which each sub-image corresponds to the difference between
image 24a and one of images 24b-24e. Data corresponding to each of sub-images
44a-44d are summed together to create processed image 46. The method shown in
FIG. 5 essentially scales the starting image by the number of remaining
images, image
24a and subtracts from image 24a each of the subsequent images. Pixel value
scaling,
noise reduction and absolute value processing can also be performed on any of
sub-
images 44a-44d and/or processed image 46.
It is noted that one or more of images 24a-24e shown in FIGS. 2, 4 and 5 can
correspond to images captured pre- or post-alarm event triggering. For
exainple,
image 24a can be a pre-event iinage with the reinainder of images 24b-24e
captured
post-trigger. It is also noted that the present invention is not limited to
the capture and
processing of five images and that any number of iinages can be captured and
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processed. It should therefore be recognized that the use of five captured
images is
presented merely for ease of explanation and understanding.
While the methods shown in and described with reference to FIGS. 2, 4 and 5,
assuine there is a predetermined time interval between the capture of each of
images
5 24a-24e, such is not necessarily the case. For exainple, as is shown in FIG.
6, time
delay 48 can be inserted between the capture of images 24a and 24b so that
processed
image 50 counts for the additional inclusion of, or substitution by, time
delay 48.
Time delay 48 can be set such that the image 24a is based on the capture of a
triggering event and any event occurring within time delay 48 is subsequently
10 captured as image 24b. For example, a person running through a zone
monitored with
a motion detector would result in the detector capturing the triggering alarm
event
resulting in the capture of image 24a, and image 24b is captured before the
runner is
able to exit the zone. This arrangement advantageously reduces the ainount of
image
data that must be transmitted and processed. As noted above, time delay 48
need not
necessarily be provided in addition to the pre-determined time interval
between the
capture of images 24a and 24b. Rather, time delay 48 can replace the pre-
detennined
time interval, and can be configured on an iinplementation-by-implementation
basis.
FIG. 7 shows still another exemplary method in which a time delay can be
used to reduce the amount of image data that is transmitted to and processed
by
central monitoring station 14. In the inethod shown in FIG. 7, time delay 48
is
inserted between image 24b and 24c in which images 24a-24c are subsequently
processed so that image 24a serves as the starting point and the data
corresponding to
images 24b and 24c are subtracted from image 24a. This arrangeinent would be
useful at a monitored door where the person has not yet entered the video
monitored
zone. Allowing a time delay between subsequent images time can be provided to
allow the person to enter the monitored zone so that a useful assessed image
can be
created and displayed.
In addition to presenting one or more processed iinages for visual
verification
by an operator of an alann event, the present invention can also be
iinplemented to
provide some other indicator when the difference between captured iinages
exceeds a
pre-deterinined tlireshold. Such an indicator can take the form of a visual
indication
on the display screen such as a pop-up box, text, or icon; or can be an
indicator that is
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separate from the display screen such as a separate light, sound and the like.
In this
maimer, an operator can be alerted that the changes are significant enough
that the
operator should pay careful attention to the processed image or images
presented for
visual verification.
As noted above, image processing can also include processing to remove
noise. This can be done, for example, by setting an intensity threshold level
in the
processing software such that when two image data corresponding to two images
are
subtracted, only those pixels having a value above a certain pre-determined
threshold
are displayed. In that same vein, the total number of pixels that have crossed
the
noise threshold can be expressed as a percent of the total number of image
pixels can
be provided to the operator on the display screen and used as a figure of
merit to
determine if there is a reasonable expectation that there was a significant
change
between the two images being compared. This figure of merit can be saved in a
database, such as a database on central monitoring station 14, for archival
purposes.
This figure of merit can be used as the basis for comparison with the pre-
determined
threshold in order to determine whether or not the indicator should be enabled
and
provided to the operator.
As noted above, it is possible that the subtraction operation during
processing
can yield a negative, and hence, undisplayable pixel, and that one way to
address this
issue is to scale (shift) the image display values. One way to accomplish this
is to
scale the pixels using the following method:
C = ((A-B) / 2) + (R / 2)
where C equals the value of the pixel to be displayed, A is the value of pixel
A from a
first image such as image 24a, B equals the value of a corresponding pixel
from the
image to be subtracted, such as image 24b, and R is the total range of levels
in the two
images. If additional contrast is needed, an additional scaling factor can be
added as
follows:
C = (x(A-B) / 2) + (R / 2)
where x is a scaling factor greater than 1. If x is such that C > R, then a
limiting
algorithm can be einployed such as: if C > R, then C = R, and if C < 0, then C
= 0.
While the contrast level can be established automatically within the
progranunatic
software, processing the images, it is contemplated that the contrast level
(x) can be
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made adjustable by the operator, for example by providing a slider in the
display
window showing the image, or a separate input area on the display screen, and
the
like.
The present invention advantageously provides a method, system and central
monitoring station which allow image processing for display and visual
verification
by an operator to be accomplished using a software application that can reside
on
central monitoring station 14 and which does not require extensive computing
power
to operate. As such, the programmatic software used to implement the above-
described functions does not require a significant amount of computing power
because it is not performing extensive digital signal processing ("DSP"). The
present
invention therefore lends itself to implementation in the form of a small
application
program that can be resident on and executed by central monitoring station 14.
Of
course, the software application iinplementing the above-described functions
can also
easily be provided in a more centralized server so that all image data
arriving from
one or more monitored locations can be processed by the server and then
transmitted
to one or more central monitoring stations 14 for subsequent visual
verification.
The present invention can be realized in hardware, software, or a combination
of hardware and software. An implementation of the method and system of the
present invention can be realized in a centralized fashion in one coinputing
system or
in a distributed fashion where different elements are spread across several
interconnected computing systems. Any kind of computing system, or other
apparatus adapted for carrying out the methods described herein, is suited to
perform
the functions described herein.
A typical combination of hardware and software could be a specialized or
general purpose computer system having one or more processing elements and a
computer program stored on a storage medium that, when loaded and executed,
controls the computer systein such that it carries out the methods described
herein.
The present invention can also be einbedded in a coinputer program product,
which
coinpiises all the features enabling the iinplementation of the methods
described
herein, a.nd which, when loaded in a coinputing system is able to carry out
these
methods. Storage mediuin refers to any volatile or non-volatile storage
device.
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Computer program or application in the present context means aiiy expression,
in any language, code or notation, of a set of instructions intended to cause
a system
having an information processing capability to perform a particular function
either
directly or after either or both of the following a) conversion to another
language,
code or notation; b) reproduction in a different material form. In addition,
unless
mention was made above to the contrary, it should be noted that all of the
accoinpanying drawings are not to scale. Significantly, this invention can be
embodied in other specific forms without departing from the spirit or
essential
attributes thereof, and accordingly, reference should be had to the following
claims,
rather than to the foregoing specification, as indicating the scope of the
invention.
