FIELD OF THE INVENTION
This invention relates to automated remote site surveillance for ATM
and other types of financial transaction devices; and also to machines, warehouses,
shopping malls, parking lots, small businesses, residential properties and the
like. In particular, the invention relates to the automated identification and
reporting of activities at such a site which are or may be abnormal and hence indicative
of possible endangering activity at the site.
BACKGROUND OF THE INVENTION
Currently, security surveillance of unguarded sites for burglary,
vandalism or other unlawful activity, or for augmenting protection of guarded sites,
usually involves taking video camera images of site activity and transmitting the
images to a remote central monitoring point. Detection of an actionable incident
or event at the site is left to a human observer, who periodically inspects an
array of video displays of multiple sites. Because of fatigue and other factors,
the chances of the observer falling to notice an incident are substantial. Further,
automated reading of video imagery and signal patterns to provide discrimination
among physical objects and their movement is difficult because of the complex and
expensive signal processing required to accurately discriminate discrete object
movement activity in a video pattern. Also, video bandwidth limitations of voice-grade
circuits restrict the information that can be transmitted as video images.
SUMMARY OF THE INVENTION
It has been realized that acoustic surveillance methods and apparatus
are uniquely well-adapted to detect suspicious object presence and movement within
a limited and discrete area such as an ATM or other financial transaction facility.
The acoustic signal patterns emanating from objects and their movement may be spatially
processed and the results analyzed in accordance with predetermined rules to distinguish
suspicious from routine activity.
The invention contemplates using an active acoustic system to generate
a sound signal into a site such as an ATM location, for example. Various characteristics
of the return waveform are measured. The measures include a comparison of the return
waveform to a predetermined "template" of the site with no movement activity; and
comparisons to the earlier return echoes. The measures then are evaluated according
to the rules to determine whether a given return waveform is indicative of a suspicious
The possible occurrence of a suspicious event is determined by acoustically
detecting movement activity which is inconsistent with behavioral norms for the
site. These norms are deterministic: one such norm, by way of example, is the zone
of privacy habitually afforded by the cue of customers awaiting their turn, in
consideration for the privacy of the customer currently transacting business at
the ATM. A sudden movement of a physical shape toward the user, or two or more
persons present at the machine, are automatically detected by monitoring variations
in the acoustic field pattern of the ATM area scanned.
When a defined deviation from the normal is detected, one or more
responsive and protective strategies are invoked. An alarm is sent to an attended
central monitoring station over connecting telecommunications linkages. Prioritized
information on the type of movement is displayed on the attendant screen along
with site information including site layout, access roads and alarm history. Once
alerted, the attendant may activate a local video monitor to obtain one or more
video or/and acoustic information frames for the moments immediately preceding
the alarm time. Depending on the event, the system or attendant may shut down or
restrict the money-dispensing capability of the ATM.
In accordance one aspect of the invention, return echo signals are
received by an acoustic array of multiple pickup receivers mounted on or near to
the ATM, and directionally oriented to monitor echoes returning from particular
azimuth angles within the beam of the receivers.
The invention and its further aspects, features, and implementations
will be more readily appreciated from a reading of the description to follow of
an illustrative embodiment.
DESCRIPTION OF THE DRAWING
DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT
- FIG. 1 is a schematic drawing of an active ATM site with user cue;
- FIG. 2 is an isometric diagram of an ATM machine augmented with an active acoustic
- FIG. 3 is a detailed schematic diagram of directional mounted microphone arrays
for detecting return acoustic echoes of an active acoustic pulse;
- FIG. 4 is a schematic circuit diagram of an electrostatic microphone/transducer
used in the array;
- FIG. 5 is a top view diagram of the acoustically monitored field in front of
the microphone array, showing an exemplary customer cue;
- FIG. 6 is a more detailed isometric drawing illustrating the field of coverage
of the array;
- FIGS. 7 and 8 are top views of the acoustically monitored space in front of
the ATM, illustrating alert situations;
- FIG. 9 is a top view sketch of an ATM site illustrating the invention's ability
to discriminate events based on negative acoustic indicia;
- FIG. 10 is a functional block diagram of the electro-acoustic circuit;
- FIG. 11 is a flow chart of the signal processing of the FIG. 10 apparatus;
- FIG. 12 is a schematic diagram illustrating detection of physical objects in
the view of the array;
- FIG. 13 is a further flow chart describing signal processing for data abstraction
to achieve discrimination; and
- FIG. 14 is a high level functional block diagram of a full system for practicing
the invention, including details of the attendant workstation data flow and display
As seen in FIG. 1, an ATM machine 10 installed in an ATM area or
enclosure 11 (spatial zone) is augmented with an active sonar 12 which actively
acoustically monitors the area in front of ATM 10 in a manner to be described.
Machine 10 is in use by a customer 13; and a line 14 of waiting customers is formed.
Persons familiar with ATM usage recognize the "courtesy" space afforded to the
current machine user 13 by the cued customers, providing the current user 13 a
zone of privacy denoted 15 in which the user 13 can conduct transactions in relative
FIG. 2 shows an active sonar 12 mounted on top of machine 10 to acoustically
survey the spatial zone 11 in front of and around the machine. The active sonar
12 may be mounted elsewhere in the ATM spatial zone instead of on the machine 10
itself. FIG. 2 also shows a video camera 16 and an audio transceiver 17 mounted
in spatial zone 11. A local controller 18 mounted internal to machine 10 provides
communications control between camera 16 and transceiver 17 to a remote monitoring
site through a network connection 19. Certain functionalities of the ATM itself
may, in accordance with the invention, also be linked to controller 18 through
connection 20, and controlled remotely in a manner to be described.
FIG. 3 shows a specific version of active sonar 12 as consisting of
an array of directional microphone/transducers 21 each generating bursts of sound
or "pings," and each functioning as a microphone to receive return echos from the
pings. Microphone mount 22 is shaped to orient individual transducers to cover
the space of the spatial zone 11 at 3 degree horizontal azimuth angle intervals,
subtending about 120 (or more as necessary) horizontal degrees and 20 vertical
degrees as measured from the horizontal. The 3 degree directional intervals may
be achieved by providing a succession of flat surfaces 23 on mount 22 which differ
in their horizontal orientation by 3 degrees. As seen in FIG. 5, the horizontal
orientation of active sonar 12 enables physical objects in front of machine 10
including machine-using customer 13 and the cued-up customers 14 to be acoustically
detected by the microphones of the transducers 21 that make up the horizontal angle
The transducer 21 may be of the electrostatic type shown in FIG. 4,
consisting of a metal substrate 23, a mylar layer 24, a deposited metal coat 25,
and a power supply circuit 26.
The continuous acoustic surveillance of area 11 illustrated in FIG.
6. The active sonar 12 sends out "pings" denoted 27, which encounter objects denoted
13, 14, 29 from which echos 30, 31, 32, 33 are returned. The echos returning from
various known directions are pattern information that enables signal processing
equipment, to be described below, to detect a wide variety of physical activity.
For example, the event depicted in FIG. 7, where 2 or more persons are positioned
in front of machine 12, is one type of acoustically detectable event which is defined
as actionable activity. Here, the entity 34 may be a person who has intruded on
the zone of privacy 15 of customer 13. The event illustrated in FIG. 8 consists
of rapid movement of an entity as denoted the footstep path 35 from the far acoustic
field to or toward the ATM-using customer 13. The very onset of any rapid movement
within the purview of array 12 exemplified by the preceding can be detected as
signal amplitudes representing return echos; and is an event that triggers an alarm.
Further in accordance with the invention, a "negative" acoustic return
echo may also signify the occurrence of an actionable event. To illustrate, referring
to FIGS. 6 and 9, ATM machine area 10 includes a window 36 or other closure. One
of the microphone/transducers 21 is permanently pointed at the window 36; and a
normal echo 37 signal is returned by the window as an electrical signal received
in time. If window 36 is disturbed by opening or breaking, the electrical signal
37 is substantially reduced in amplitude, which registers as a relatively negative
signal in the same time slot.
Similarly, referring still to FIG. 9, a person 38 may enter the machine
area 11 through an access door 39 and locate in a place such as 40 that is not
directly accessible by the pinging signals 41 or by video camera 16. The original
entry of person 38 through door 39 registers as a positive echo signal; but the
subsequent disappearance of person 38 as a now negative echo signal is also detected.
Taking the two events together, it may be concluded that the person has occupied
the blind space 40. Over a long enough time this condition is taken as indication
of a lurking intruder; and an alert is automatically triggered. Detection of a
lurking intruder in a blind spot may also be registered from monitoring the reflected
energy from the relevant search beam and nearby beams, to look for change in the
reverberant field of that sector.
The acoustic signal generation, detection and data processing which
permits the critical discrimination between normal vs. suspicious events will now
be further described.
Referring now to FIGS. 4 and 10, an illustrative hardware configuration
is shown for detecting, analyzing, discriminating, displaying and reacting to
suspicious movements or disappearances in the area of the ATM. The pulse and detection
timing sequence is set to survey objects within about 25 feet of the active sonar
12. An operating cycle for the system, shown in FIG. 15, consists of transmission
of an acoustic energy pulse for a period of 0.4 msec., a wait period of about 0.6
msec to allow the transmit diaphragm to damp, a receive period of about 49 msec.
during which the echo signal energy is detected and analyzed, and finally a silent
period during which the system is shut off. Electronic tone generator 41 is triggered
by local control/processor 42 to produce a 50 KHz electrical signal. This signal
is amplified in amplifier 43 to 10-50 milliwatts and applied to transmitter 44
for a 0.4 msec. period. The resulting acoustic pulse is propagated into essentially
all of the 3-dimensional space in front the ATM enclosure.
In the receive phase, the echo signals from all objects within the
focus of the array are received, essentially as separate packets or envelopes of
acoustic energy at the microphones such as microphone 45. Each packet is received
at a time that varies directly within the distance to the object from the array.
The energy of each packet varies inversely as the square of said distance, but
directly in accordance with the relative size of the object. An alternative drive
circuit for the active sonar is shown in FIG. 4 where a 1-component transmit/receive
transducer is switched between transmit mode and receive mode by switch 47.
The echo signal characteristics are converted to electrical signals,
the amplitudes of which are used to build a spacial map, or frame, containing all
objects in front of the ATM. A sequence of these frames are analyzed to identify
alerts. Specifically, the received echo signals are amplified in amplifier 46 and
fed to a detector 48 which recognizes discrete amplitude bursts above a set threshold.
This threshold may, for example, comprise a quiescent state "template" of the fixed
or invariant echo characteristics of the enclosure. The template may be generated
by analyzing the echoes created in response to one or a succession of pings launched
at a time when human activity at the site is not occurring, such as when the facility
is closed down. The quiescent condition template information is then subtracted
from all frames to concentrate frame-to-frame analysis upon signal energy which
is caused by objects occupying or moving within the ATM area
If objects such as humans are in the purview of the active sonar 12,
the objects will be manifested as energy envelopes or bursts which remain after
the template detail is subtracted out. These bursts are then digitalized in A/D
converter 49. Advantageously, converter 49 has a capacity to handle about 40 channels
with a sampling rate of at least 6.4 KHz with 12 - 16 bit data. Output from A/D
converter 49 is sent to local control/processor 42.
One device suitable for performing the functions of processor 42 is
an Ariel MP-3210 Dual DSP 3210 ISA card. Spatial processing and information processing
functions may be provided by DSP32C or equivalent. Processor 42 also generates
transducer transmit and microphone control signals. Processor 42 formats the data
into a sequence of samples, which form each successive frame or spacial map. These
samples are stored in a local memory in processor 42.
Data critical to identifying suspicious events now is abstracted from
the stored samples by, for example, a separate computation unit 50 which contains
spatial processor 51 and information processor 52. Spatial processor 51 forms for
each frame a 2-dimensional image of objects in the beam area covered by each directional
microphone. The image data includes relative direction, distance of the image from
the transmit/receive apparatus on the ATM, and amplitude the latter being a measure
of the image size. As illustrated in FIG. 12 which shows sample objects at distance
ti on beams number 1 and 2, object location with respect
to each microphone 45 is a function of beam number and delay. Size and other attributes
of the object are represented in the amplitude magnitude. Comparison of successive
frames of data provide indicia of the velocity of a moving object. These data are
fed to information processor 52 which converts the data of the image samples to
indicia of location of moving objects, their relative movement with respect to
each other, and other measures.
The steps for the above-described signal processing are further outlined
in the process flow chart of FIG. 11. An envelop of return echo signal energy is
received by each of the microphones 45. Each envelop is measured individually and
a digital reading for each is created and stored. Data is collected long enough
to assure that the "ping" wave travels to the most remote reach of the spatial
zone 11; and any echo has travelled back to the microphones 45. The number of samples
taken advantageously corresponds to a time interval of about 50 msec between reads,
in order to generate and analyze data in near-real time for fast alerting of abnormal
events. When this time is reached, a "completed" decision is effected, which triggers
the data abstraction analysis in accordance with the process flow chart of FIG.
The nature of the acoustic data collected and the relative ease of
its analysis is a strength of the invention, because of the precise directionality
afforded by the active sonar 12, and the fact that return signal amplitudes and
the times of receipt provide highly reliable data on which to base useful events
analysis. The raw data is filtered to remove noise and reverberation characteristics
(the "template" referred to earlier) of the enclosure. New objects, new "holes"
and object/"hole" movement are identified.
Referring back to FIG. 12, the separate digitized signal amplitudes
exceeding the threshold are equalized. The spatial processing may be enhanced by
merging the equalized signals in adjacent beams which are at or about the same
distance from the array. For example, 1 and 2 are shown to have detected object
clustered in adjacent cells of the array. These object pulses are merged into a
single pulse because they are likely to emanate from a single discrete object.
The distance to each identified object is determined by the beam whose merged signal
(maximum amplitude) is deemed most reliable. The merging step helps discriminate
objects in the present instant by correlating them to the same objects of previous
scans. The size of the object defined by merged signals may be estimated more closely
by determining the number of beams the object is detected on.
To determine movement in time, an updated spatial representation of
the scene is formed. Each collected frame of data is subtracted from the preceding
frame of data. A "hole" is signified by the absence of a return pulse in the present
frame where in the previous frame or frames one was present at a given matrix point.
Objects that appear on the scene are detected as positive peaks; and objects that
disappear are detected by noting negative energy peaks or "holes." The updated
spatial data identifies any newly-arrived or newly-moving objects as signified
by the presence of an echo at the given matrix point where previously an echo did
The tracing of movement is a matter of logically tracking the path
of "holes" and "peaks" movement over the scanned matrix. If a "hole" has moved
to a contiguous cell in unison with the movement of an adjacent positive peak,
it is interpreted as a movement of the object from a "hole" to a peak.
Using the information on moving objects identified by the data abstraction
process, several searches and comparisons are then performed to determine if an
alarm situation should be signalled. A normal transaction is the case of a single
object tracked in an approach to the ATM machine, which remains close to the ATM
for a limited time period to allow transaction completion. This event is declared
or labelled a routine "customer" activity. However, movements connoting alarm situations
include: (1) two or more objects which simultaneously approach the ATM machine;
(2) a single identified object which approaches the ATM machine but does not use
it by the end of some predetermined period of time; (3) a previously labelled customer
that is still in front of the ATM machine after the predetermined allowed period;
and (4) any object that approaches a previously identified routine user no matter
what the user's location may be.
Additionally, a sudden disappearance of a return pulse in a beam that
is directed, for example, to a window, a counter, or a door of the enclosure, is
by definition an alarm. A further alarm condition is the disappearance of a previously
identified moving object signalled by the appearance of a "hole." This condition
might signify presence of a person lurking out of the acoustic beam's reach under
A further alarm condition may be the lack of movement over some long
time interval of a previously moving object, which could signify, for example,
a person who had crouched under an ATM service counter if present in the enclosure.
Many other alarm conditions beyond these examples will occur to persons skilled
in the art, which the spatial analysis of the invention can detect.
The invention as so far illustrated may be usefully integrated into
a remote monitoring system for one or several financial transaction devices. While
a variety of specific arrangements may be envisioned, an exemplary such system
with its particular attributes is described in FIG. 14.
One or more ATM machines 10 each served by an active sonar 12 are
located at ATM site 90. The data processing and abstraction capability described
hertofore may be located at the ATM site, or may be provided at some location
remote from the site 90. Alarm conditions are automatically signalled by local
controller 18 to a remote monitoring location 100 through network connections 19
to a telecommunications network 110 which comprises lines of at least voicegrade
Condition signals are received at a workstation denoted 120 at the
monitoring location. The workstation 120 has an alert screen display 160 served
by buffer 122. A communications controller 130 interfaces the workstation to the
network 110 through two-way communications lines 111. Controller 130 may include
adjuncts (not shown) such as a modem pool and line concentrator to manage incoming
and outgoing traffic.
Incoming message priority assessment unit 140 establishes priorities
among alarm situations. Its processes are rule-based, addressing factors such as:
what type of event as detected by the analyzed data precipitated the alert message;
what is the priority of the alert; and given the presently-active alerts, what
is the relative urgency of the new alert. These considerations are programmed as
rules into the unit 140.
The rules may work as illustrated in the following example. Suppose
that several alerts are currently in effect and the attendant at remote location
100 is managing one of these alerts, which is a "rapid approach to ATM user." Now,
a new alert is received by the attendant workstation, for which the data abstraction
unit has determined that two objects are approaching some other ATM machine. On
response to this new input, the alert display 160 presents information signifying
"two people at ATM" for this further site. In this case, although the new information
is displayed, the workstation priority-setting program does not direct the attendant
to interrupt the on-going review and handle the new alert.
If, however, the attendant was reviewing a "two person approach" in
progress, and the new alert constituted a "rapid approach" situation, the priority
assessment unit 140 interrupts the present review by, for example, opening a window
on display 122 accompanied by a tone signal. The window showing the new alert
explanation and, if available, a still frame video of the new alert scene.
An on-line database 150 collects information from the output of unit
140, and also has access to site data and history information from site history
store 170. The history file includes prior alert instances, and location map information.
In response to a specific site alert, the display buffer 122 provides a visual
image of the streets and access roads for the ATM site in store 170; and also a
plan view of the specific ATM site layout with walls, counters, polls, doors, etc.
As new alert information is received for a given site, data on the date and type
of event is entered into a permanent file for the site also contained in store
141. This accumulated data bank enables ATM site managers to recognize particular
security problems, patterns of ATM robberies and other facts; and react accordingly.
Site history will vary; and for sites which experience relatively
more alerts and particularly for those experiencing more actual criminal activity,
the system may be set to effect a periodic "page" of such sites. The "page" shows
on display 160, for example, in the form of a prompt to the attendant to view a
paged video still shot, for example, once very 10 minutes.
When the system registers no alerts at any ATM sites, which is likely
to be a great majority of the time, the system provides automatic polling of selected
sites. The attendant thus can routinely examine the acoustically-generated object
movement data, the video-generated current site still shot, and the available audible
activity, as added surveillance capability.
The system also advantageously may contain a two-way continuously
open voice link 180 to each ATM location from the remote monitoring station, enabling
the attendant to engage in two-way conversation with persons at a site, or to listen-only
as needed. The site includes an audio microphone and receiver unit 19 for this
function with voicegrade circuits 111 linking unit 19 and the site and remote monitoring
station 100. Voicelink 180 may include a screen switch control for operator use
At the ATM sites a video camera denoted 16 in FIG. 2, provides periodic
video images. Using video compression and other well-known techniques for transmitting
video signals over narrowband telephone lines, a video image may be transmitted
to monitoring site 100 at least every 3 seconds. When video is provided in conjunction
with the present invention, controller 130 feeds the video information to video
frame buffer 121 for referral to display 160 through display buffer 122. In addition
to the remote monitoring and response to detected alarm conditions, the system
may also generate a visual or audio alert locally, which advantageously may be
located so as to be unnoticed by the ATM users, but which enables locally cognizant
persons such as a bank security guard to investigate and, if indicated, intervene.
If on reviewing and evaluating alert information, the attendant determines
police help is needed, an autodialer 190 provides automated voice calling to security
patrols or to the local police. Autodialer 190 identifies the alerting site, and
provides a brief, concise recorded statement describing the alarm condition. An
audio statement of the site history file may be included in the automated message.
Dialer 190 also records all voice transactions to tape unit 191, supplying time,
date and site stamps for the record.
A voice link may also be opened between the site and the security
patrol or the police. These further communications capabilities may assist in deterring
or thwarting an attempted robbery, and further enable the public to be more comfortable
in their use of ATM facilities.