Note: Descriptions are shown in the official language in which they were submitted.
215'742
INTERACTIVE SURVEILLANCE DEVICE
FIELD OF THE INVENTION
The present invention relates generally to automated
electronic security devices, and more specifically to an
automated surveillance device using a plurality of passive
infrared sensing devices to determine azimuth and an
ultrasonic transceiver to determine range and resulting
elevation for an elevated camera.
BACKGROUND OF THE INVENTION
The monitoring of areas for various purposes, such as
traffic control, animal or human intrusion deterrence,
and/or surveillance for security or other purposes, has
become increasingly important with population increases and
the pressures of a more complex society. Such concerns are
often apparent to the observer, who may readily note remote
camera installations and security guards and personnel in
banks, shopping malls and other areas, as well as pneumatic
or other traffic monitoring devices on the road. Such
devices and services can be relatively costly, particularly
in the case of monitoring or security personnel. However,
in some situations there have been no suitable alternatives
to such personnel due to the relatively high power demands
of many security systems, such as floodlighting for camera
surveillance, etc., as well as the need for human
observation.
1
215'742
The need arises for a surveillance system which is
capable of operating upon demand, i. e., when an intruder
or intruders approach the area covered by the system. The
system should require relatively low power in normal use,
as the additional power required for lights, audio devices,
cameras, etc. need only be supplied when required by the
primary sensing means. The primary sensing means should
be of a passive nature, which renders such sensing means
more difficult to detect, as well as further reducing power
demands and costs. The system should respond to the needs
of surveillance security, by providing a relatively high
resolution, narrow field of view video of any intruder in
the area, by means of a secondary range determination
system providing input to a camera control for elevation
and control of the focal length thereof. Moreover, the
system should be relatively inexpensive to manufacture and
operate in comparison to other systems developed.
DESCRIPTION OF THE PRIOR ART
U. S. Patent No. 2,700,318 issued to James Snyder on
January 25, 1955 discloses a Gun Muzzle Blast Indicator
using fixed lenses and progressive density filters. Light
from the blast will strike the filters at different points,
depending on the direction of the blast relative to the
lens orientation. The device determines only direction and
is incapable of determining range or elevation, or of
interacting with another device (e.g., camera or
rangefinder) .
2
~21~7742
U. S. Patent No. 2,961,545 issued to Robert W.
Astheimer et al. on November 22, 1960 discloses a Tracker
For Moving Objects directed primarily to the tracking of
rockets and/or high speed aircraft having significant heat
radiation. The device uses two passive infrared detectors
(PIRs), each having a relatively wide field of view, for
azimuth and elevation, and two additional PIRs, each having
a relatively narrow field of view, for "fine tuning" of the
azimuth and elevation of the target. The device is
completely passive, and thus is incapable of providing
range information.
U. S. Patent No. 3,703,718 issued to Herbert L. Berman
on November 21, 1972 discloses an Infrared Intrusion
Detector System using a single PIR detector and a series
of mirrors or lenses to broaden the field of coverage of
the detector. While the system may be activated by the
passage of a heat source across the mirror or lens array,
no means is provided to pinpoint either the direction or
the distance of the heat source nor to activate any camera
or recording means, as a camera could not be aimed by the
device with sufficient precision to be useful.
U. S. Patent No. 3,760,399 issued to Frank Schwarz on
September 18, 1973 discloses an Intrusion Detector having
a thermopile sensor comprising a plurality of
t,
thermocouples. The device depends upon movement of a heat
source across the plural thermocouples to create a varying
voltage to trigger an alarm. The device is thus incapable
of pinpointing a specific direction or azimuth for an
3
2157'42
intruder, or of determining range, thus rendering the
device unsuitable fox use with a camera.
U. S. Patent No. 3, 924, 130 issued to Allen Cohen et
al. on December 2, 1975 discloses a Body Exposure Indicator
which may detect infrared radiation from intruders or other
sources in the field covered by the device. The device
utilizes a mapping system which stores the standard field
of view into memory, and a comparator which triggers an
alarm when the scanned field does not match the mapped
field. Cohen et al. disclose the use of a camera having
a relatively narrow field of view, so as to pick out
individuals in the scanned field, as does the present
invention. However, Cohen et al. fail to disclose any
means for aiming the camera precisely in the scanned field,
nor of determining range or vertical angular elevation to
the infrared source in the field in order to focus a camera
accurately, as in the present invention:
U. S. Patent No. 4,769,545 issued to Jacob Fraden on
September 6, 1988 discloses a Motion Detector comprising
a single PIR detector having a relatively wide angle field
of view. Fraden notes that such devices react to changing
temperatures, and thus relies upon two intertwined
electrodes to detect an infrared source. As the source
crosses the electrodes, a temperature difference will be
detected and converted to an electrical signal. However,
the relatively wide field of view results in essentially
the same signal being created at any time an intruder
crosses any part of the field of view; the device is
4
2~57'~4~
incapable of pinpointing the specific azimuth or elevation
of an intruder. Accordingly, no camera is provided, due
to the inability of the device to aim such a camera
precisely.
U. S. Patent No. 4,772,875 issued to James F. Maddox
et al. on September 20, 1988 discloses an Intrusion
Detection System which includes a plurality of different
types of sensors in a horizontal radial array, with
additional sensors rotatable relative to the first sensor
array. The device is a mobile robot and is incapable of
continually scanning a given field due to the need to stop
any motion of the robot to confirm whether changes in the
status of the sensors are due to motion of an intruder or
to motion of the robot. The present invention is
permanently installed and affixed to a permanent structure,
which eliminates such problems. The Maddox et al. device
utilizes radar or "microwave sensors" for range finding to
an intruder and a plurality of ultrasonic transducers
positioned around the body portion for maneuvering and
collision avoidance, although the possible use of a single
ultrasonic device for the determination of range to an
intruder is also noted. As the mobile Maddox et al. robot
may only be used on a smooth, relatively level surface, no
means is provided for the determination of differential
elevation (if any) to an intruder, as provided for by the
present invention. While provision is made to activate a
camera when an intruder is sensed, no means is provided for
adjusting the focal length of the camera depending upon
5
2157742
range to the intruder, nor for adjusting the angular
elevation of the camera, as it is assumed that the intruder
is on the same flat, essentially level surface as the
robot. The present invention provides for camera focal
length adjustment as well as azimuth adjustment, and
further recognizes that differences in elevation between
the installation and an intruder due to installation and/or
terrain, result in a need to adjust the elevation of the
camera for an accurate, relatively high resolution picture.
Moreover, Maddox does not store a record of range
information produced by the ultrasonic devices, as the
Maddox robot is intended to be moving and thus any
distances to other objects and ultrasonic reflections will
always be changing. The present surveillance device is
stationary, and accordingly "maps" of ultrasonic reflected
distances are recorded and stored for comparison with those
produced when the device is activated.
U. S. Patent No. 4,823,051 issued to William A. Young
on April 18, 1989 discloses an Infrared Actuated Control
Switch Assembly providing for the operation of an overhead
light in a room. Two 360 degree conical viewing fields are
provided for the detection of persons entering and
remaining in a room. The passive infrared detectors of the
present invention subtend a sufficiently broad vertical
angle as to cover the required elevation range without need
for two vertically spaced apart units or lenses . Moreover,
the Young device seeks only to turn a light on or off, and
thus no additional aiming apparatus or circuitry is needed,
6
.2157742
as in the present invention. As the Young device does not
sense the specific direction of the heat source, it cannot
provide for the aiming of a camera, as in the present
invention.
U. S. Patent No. 4,890,093 issued to James R. Allison
et al. on December 26, 1989 discloses a Solar Powered
Proximity Triggered Light. No means is disclosed for the
determination of a specific direction, distance or
elevation of an intruder from the detector, and thus no
camera is provided, as it would be impossible to aim such
a camera properly without information pinpointing the
location of the intruder.
Finally, U. S. Patent No. 4,896,039 issued to Jacob
Fraden on January 23, 1990 discloses an Active Infrared
Motion Detector And Method For Detecting Movement. As
indicated by the Fraden '039 patent title, the device
transmits an infrared signal at a temperature above ambient
( i . a . , shorter wavelength or higher frequency) and detects
any reflected radiation in the transmitted wavelength. The
infrared transmittal, and the additional energy required
and possibility of detection by an intruder, are problems
obviated by the passive nature of the present invention.
Moreover, while means for intruder detection is disclosed,
no means is provided for pinpointing the precise direction
or azimuth of the intruder, nor the vertical elevation and
range. Accordingly, no camera is disclosed, as the
accurate aiming of such a camera is impossible without the
ability to locate the intruder precisely.
7
2157'42
None of the above noted patents, taken either singly
or in combination, are seen to disclose the specific
arrangement of concepts disclosed by the present invention.
SUMMARY OF THE INVENTION
By the present invention, an improved interactive
surveillance device is disclosed.
Accordingly, one of the objects of the present
invention is to provide an improved interactive
surveillance device which may be used for a variety of
purposes, such as surveillance of intruders and/or tracking
an intruder with a camera and/or light.
Another of the objects of the present invention is to
provide an improved interactive surveillance device which
utilizes a purely passive means of surveying the scanned
area, and which activates an active transceiver to
determine the range of an intruder precisely when an
intruder is passively detected.
Yet another of the objects of the present invention is
to provide an improved interactive surveillance device
which controls a camera, and provides for the precise
control of azimuth, angular elevation, and focal length of
the camera to provide a relatively high resolution picture
of an intruder.
Still another of the objects of the present invention
is to provide an improved interactive surveillance device
which does not require the intervention of a human
operator.
8
2157e2
An additional object of the present invention is to
provide an improved interactive surveillance device which
includes a passive determination of the approximate size
of an intruder, by means of the range determined by the
transceiver, energy received by the passive devices, and
appropriate microprocessor and/or computer programming.
A further object of the present invention is to
provide an improved interactive surveillance device which
utilizes passive infrared detectors for continuous
surveillance of the subject area, and an ultrasonic
transceiver for active determination of range, with the
ultrasonic device remaining inactive until activated by the
detection of an intruder by the passive infrared detectors.
An additional object of the present invention is to
provide an improved interactive surveillance device which
is capable of scanning a field of at least 180 degrees of
azimuth, and further precisely aiming a camera at an
intruder within that field.
Yet another object of the present invention is to
provide an improved interactive surveillance device which
is capable of operating in darkness and/or relatively low
light conditions, by means of auxiliary lighting actuated
by the device and/or an infrared or low light camera.
Still another object of the present invention is to
provide an improved interactive surveillance device which
requires relatively little electrical power until activated
by an intruder, due to the passive nature of the primary
surveillance means.
9
n157742
A final object of the present invention is to provide
an improved interactive surveillance device for the
purposes described which is inexpensive, dependable and
fully effective in accomplishing its intended purpose.
With these and other objects in view which will more
readily appear as the nature of the invention is better
understood, the invention consists in the novel combination
and arrangement of parts hereinafter more fully described,
illustrated and claimed with reference being made to the
attached drawings.
BRIEF DESCRIPTION OI~' THE DRAWINGS
Figure 1 is a perspective view of the present
invention showing its various major components.
Figure 2 is a side elevation view showing the camera
tilt mechanism and other features.
Figure 3 is a block diagram of the circuitry used in
the present invention.
Figure 4 is a flow chart of the operation of the
present invention.
Similar reference characters denote corresponding
features consistently throughout the several figures of the
attached drawings.
215'742
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now particularly to figure 1 of the
drawings, the present invention will be seen to relate to
an automated interactive surveillance device 10, providing
for the remote, automated surveillance of an area, e. g.,
automated bank teller machines, high security parking
areas, unattended property, storage areas, and other areas
which may be subject to vandalism or damage, etc. The
primary sensing means of the present surveillance device
10 is an array of passive infrared detectors 12,
hereinafter generally called "PIRs" throughout the present
specification. The PIRs 12 are passive, in that they only
receive energy, and do not transmit energy as an active
device would which relies upon the reception of reflected
energy from its own transmission (e. g. , radar) . Thus, the
present surveillance device 10 cannot be detected by other
devices which may receive transmitted energy, until the
present device 10 has already been activated by an intruder
as discussed further below. The passive nature of the
present interactive surveillance device 10 also results in
relatively low energy consumption until activated, as well
as lower costs due to the lack of infrared transmission
means required.
The array of plural PIRs 12 is installed in a
stationary base portion 14 which may be permanently
installed and immovably affixed to a stationary supporting
structure, e. g., the building B of figure 1. A weather
shelter 8 or the like may be installed over the device 10
11
21~7~42
as desired, to provide some protection from the elements.
While most of the components of the device 10 may be
completely enclosed as they rely upon purely passive
reception of energy and do not transmit, an ultrasonic
rangefinder transceiver (described further below) is
provided, and at least the transmitting antenna or orifice
must be exposed. (Alternatively, other transceiver types
may be used, e. g., microwave, etc.) The stationary base
portion 14 serves as a base for a rotatable portion 16
disposed thereabove, as well as serving as a housing for
other components of the device 10 described further below.
The rotatable portion 16 is mounted on a substantially
vertical rotary shaft 18 driven by a stepper motor 20
housed within the stationary base portion 14 (figure 2).
A camera 22 ( a . g . , video camera, inf rared camera or camera
adapted to low light levels, or other camera as required)
is mounted atop the rotary platform 16 by means of an
arcuately pivotable camera mount 24 having a substantially
horizontal pivot axis 26, thus enabling the camera 22 to
travel in a vertical arc to adjust its angular elevation.
The adjustment of the arcuate elevation of the camera 22
is provided by a pivotally mounted camera adjustment motor
2 8 ( f figure 2 ) , which may drive a j ack screw 3 0 or other
means adapted to provide for the tilt or angular elevation
adjustment of the camera 22.
12
CA 02157742 1999-04-19
An ultrasonic rangefinder 32 is also affixed to the
rotatable platform 16, preferably attached to the camera 22 so
as to be automatically aimed in the same direction as the
camera 22 at all times. Optionally, a light 34 may be
installed atop the rotary platform 16, preferably also affixed
to the camera 22 and permanently aimed in the same direction
as the camera lens. The camera 22, camera adjustment motor 28,
and rangefinder 32 may communicate with the electronic
circuitry housed within the stationary base portion 14
respectively by means of cables 36, 38, and 40. (Light 34, if
so equipped, is also connected to the base portion by a power
cable, not shown.)
Figure 3 provides a disclosure of the electronic circuitry
contained within the stationary base portion 14 and providing
for the operation of the present automated interactive
surveillance device 10. In Figure 3, eight different PIR
circuits (for eight different PIRs), comprising a PIR circuit
block 42, are disclosed. As noted above, the entire field
scanned by the PIR array subtends 180 degrees horizontally
thus, each PIR of an array of eight PIRs will subtend a
substantially equal horizontal field of 22.5 degrees. The PIRs
are installed within the stationary base portion 14 of the
device, behind a fresnel lens 48 (Figures 1 and 2) which
provides a total of 180 degrees of coverage, and which serves
to segregate the individual fields of view of each of the PIRs
12 by means of barriers. (The present
13
2157742
surveillance device may be operable with as few as four
pIRs, but directional sensitivity, and the resulting
ability of the device to aim and adjust the focal length
of a camera, will be somewhat less than with a greater
number of PIRs each subtending a narrower field of view.)
Each of the PIRs (such as the PIR 12 shown at the top of
the PIR circuit block 42) communicates with a PIR circuit
44, each of which provides a signal to an amplifier circuit
46 (one of which is shown in PIR circuit no. 8 of the PIR
circuit block 42).
The signals from each of the PIRs 12 are supplied to
an analog-to-digital (A/D) converter 50, which may be
physically located with the microcontroller 52 of the
device. (It will be understood that, as each of the PIR
signals must be separated from every other PIR signal in
order for the microcontroller 52 to determine which PIR(s)
is/are being triggered, that the cable 54 from the PIR
circuits to the A/D converter actually comprises a
sufficient number of independent lines to provide separate
signals from each PIR to a dedicated channel of the A/D
converter. As an example, the eight PTR array shown in the
drawing figures of the present surveillance device 10
provides signals to an eight channel A/D converter through
eight separate lines between each of the PIRs and a
corresponding A/D converter channel.) The microcontroller
52 in turn provides a signal to a sensitivity adjustment
circuit 56, which circuit 56 provides adjustment to the
PIRs 12 to preclude their being triggered or activated due
14
21e742
to relatively small heat sources toward the range limits
of the device 10.
Other input to the microcontroller l2 includes a
camera height indicator 58 comprising a plurality of
switches, e. g., four switches in a four bit hexadecimal
array. Thus, height indicator 58 could represent 16
different settings for heights from 0 to 15 feet in one
foot increments (or 0 to 7.5 feet in six inch increments,
etc.). The microprocessor 52 reads the switch setting of
the height indicator 58 and uses the height information to
initialize a central tilt angle approximating aim at a
target in the mid-range distance. This height information
is also used in combination with range information provided
by the transceiver 32, to determine the angle of tilt of
the camera 22 to aim at a target within the field being
surveyed, according to a trigonometric algorithm discussed
below. Input to the microprocessor 52 is also provided by
limit or "home" switches 60 for the platform stepper motor
and the camera tilt adjustment motor 28, which preclude
20 motor operation past predetermined arcuate limits and
reposition the camera and platform to a central position
after actuation, and a photocell input 62 serving to
disable the light 34 during daylight or relatively bright
conditions. The microcontroller 52 also receives input
from the receiver of the ultrasonic transceiver 32, after
the transmitter portion has been activated by the
microcontroller; the specific operation is described
further below.
Microcontroller 52 is programmed to provide output to
control the platform motor 20 to position the rotatable
platform 16 as required by means of a panning control
circuit 64, and to provide output to a camera tilt control
circuit 66 to position the camera 22 relative to the tilt
angle. Once the camera 22 has been positioned, the
microcontroller 52 will operate the camera by means of the
camera control circuit 68, which circuit 68 turns the
camera 22 on and off and controls the focal length of the
zoom lens 70 (figures 1 and 2) as required. The
microcontroller 52 also serves to actuate a video recorder
when the camera 22 is actuated, by means of VCR control
lines 72, to actuate the flood lamp or light 34 as required
according to the signal received from the photocell 62 by
means of a flood lamp relay 74 , and to provide a signal
(video output, alarm, etc.) to a remote monitoring station
by means of a communication port 76.
Figure 4 provides a software flow chart which
describes the operation of the present interactive
surveillance device 10. When the device 10 is installed,
the camera height indicator 58 is initiated to provide the
microprocessor 52 with the proper height above the ground
or surface. The microprocessor 52 then actuates the
platform stepper motor 20 to pan the camera 22, and
particularly the ultrasonic transceiver 32 mounted thereon,
to each of the zones established by the PIRs 12 of the PIR
array in the stationary base portion 14 of the device 10.
(The zones need not be limited to the number of PIRs in the
16
21~'~'~4~
array. The microprocessor 52 may be programmed to
recognize a situation in which two adjacent PIRs are
detecting a signal, and operate the stepper motor 20 to
position the camera 22 and ultrasonic transceiver 32 to an
intermediate azimuthal position between the two adjacent
PIRs. Accordingly, there will be seven intermediate zones
interspersed between eight PIRs, or a total of fifteen
positions to which the rotatable platform may be turned in
the 180 degree semicircular field of azimuth of eight PIRs.
Four PIRs will result in a total of seven positions.) The
ultrasonic transceiver 32 is then activated at each of the
PIR zones (and/or intermediate points), and an "object
table" of the distances measured by the ultrasonic device
32 is recorded and stored in the obj ect table memory 78
(figure 3). The camera 22 and video recorder are not
activated at this time, as the device 10 is merely
"surveying" the area to establish a standard background.
This step is repeated from time to time, according to the
microprocessor programming, when the PIRs are not detecting
any significant infrared radiation.
When one (or two adjacent) PIRs 12 receive a higher
than normal amount of infrared radiation, its/their output
is sent to the microcontroller 52 via the cable 54 and A/D
converter 50. The microcontroller 52 then compares the
signal intensity received with background, and actuates the
camera pan control circuit 64 to cause the stepper motor
20 to turn the rotatable platform 16, and camera 22 and
ultrasonic rangefinder or transceiver 32, to align them in
17
~i~~~42
the direction of the activated PIR(s). The camera tilt
control circuitry 66 is also operated to position the
vertical angle of the camera 22 at a midpoint of its
arcuate vertical travel (if not already so positioned), as
the exact distance of the intruder detected by the PIRs is
not yet known. The ultrasonic transceiver 32 is then
activated to provide a new ultrasonic "map" of the area,
which is compared with the same ultrasonic "map" previously
stored in the object table memory 78 and formed during a
period of PIR inactivity:
If the two ultrasonic ranges or "maps" show
substantial correspondence, and thus no ultrasonic return
from an intruder, then the microprocessor 52 treats the PIR
activity as a false alarm due to random heating of the
environment (e. g., clouds/sunlight, reflections from
pavement or another building or window, etc.), and the
rotatable platform 16 is returned to a central position for
future operation. However, in the event that the new
ultrasonic "map" fails to agree substantially with the base
"map" data, an intruder is indicated, and the
microprocessor 52 will activate the camera 22 (and light
34, depending upon the available light as determined by the
photocell 62) and operate the camera tilt motor 28 and
adjust the focal length of the zoom lens 70 according to
the distance determined by the ultrasonic rangefinder 32
and the height of the camera established by the height
indicator 58, to provide a relatively narrow field, high
resolution view of the intruder. A video recorder is also
18
2157742
activated by means of VCR control lines 72, and a signal
may be provided to a remote post via the communication port
76 and communication/power cable 80 (figures 1 and 2).
As an example of the above, let us assume that the
lens 70 of the camera 12 is positioned fifteen feet above
the surface, measured at the base of the building B to
which the present surveillance device 10 is mounted. The
platform 16, camera 12, and rangefinder 32 are turned to
provide an ultrasonic range to an intruder, and the range
is determined to be fifty feet; the face of the intruder
is initially assumed to be approximately five feet above
the surface. Assuming the ground to be level, it will be
seen that the fifty foot distance from rangefinder to
intruder comprises the hypotenuse of a right triangle, with
the ten foot height of the camera above the face of the
intruder forming the adjacent side. The microprocessor 52
may be programmed to calculate the resulting angle of
depression or tilt angle for camera 22, by means of
relatively simple trigonometric functions, i. e., dividing
the height of the camera by the distance established by the
rangefinder to establish the cosine of the complementary
angle to the angle of depression (cos 10/50 - 0.200, -
approx. 78.4 degrees) and subtracting that angle from 90
degrees to arrive at the correct angle of depression of
approximately 11.6 degrees. (It will be seen that with
further programming of the microcontroller 52, more complex
terrain conditions may be taken into account, e. g., a
slope toward or away from the building B upon which the
19
21~'~~42
present surveillance device 10 is mounted, or conditions
of uneven terrain in different directions from the device
10.)
The above surveillance device 10 and programming
therefor may be further refined by comparing the infrared
signal intensity received by the activated PIR(s) to the
intruder distance measured by the ultrasonic rangefinder
32. A "map" of representative infrared intensities of
representative size ranges of people may be programmed into
the microprocessor 52, which may be compared with the
distance established by the rangefinder 32. If the
infrared intensity is greater (or less) than that of a
person of standard size, the angle of depression of the
camera 22 may be adjusted slightly upwardly (or downwardly)
in order to "fine tune" the vertical tilt or aim of the
camera to provide a more accurate view of the head and
upper body of the intruder.
An intruder thus discovered may be viewed for a
predetermined amount of time, or the camera and video
operation may continue as long as the ultrasonic
rangefinder continues to report an intruder in the given
direction towards which the rangefinder is.pointed and the
appropriate PIRs continue to indicate a non-standard
infrared signature: When the intrusion threat has ended
(by having infrared and ultrasonic indications return to
normal, andjor security personnel taking action, etc.), the
microprocessor will shut down operation of the ultrasonic
transducer, camera, video recorder, and light (if used),
217742
,~
and return the platform position and tilt angle of the
camera to substantially central positions, where they can
be moved relatively rapidly in either direction of travel
should another threat arise.
The above described interactive surveillance device 10
will be seen to require no external monitoring, and is
completely passive in its operation and transmits no signal
or energy until the passive infrared detectors) is/are
triggered. The device is interactive with an intruder, in
that as an intruder moves laterally, he/she will trigger
other PIRs, which will cause the microprocessor to change
the azimuth of the camera (and ultrasonic transceiver)
accordingly to continue to track (and provide a video of)
the intruder. The device serves as an extremely cost
effective means of monitoring virtually any critical area
where it is impractical to position a security guard at all
times.
It is to be understood that the present invention is
not limited to the sole embodiment described above, but
encompasses any and a11 embodiments within the scope of the
following claims.
21
