U.S. patent application number 12/329726 was filed with the patent office on 2013-08-01 for explosives and contraband detection system.
This patent application is currently assigned to United States of America as Represented by the Secretary of the Navy. The applicant listed for this patent is Dana Cottrell. Invention is credited to Dana Cottrell.
Application Number | 20130197864 12/329726 |
Document ID | / |
Family ID | 48701415 |
Filed Date | 2013-08-01 |
United States Patent
Application |
20130197864 |
Kind Code |
A1 |
Cottrell; Dana |
August 1, 2013 |
EXPLOSIVES AND CONTRABAND DETECTION SYSTEM
Abstract
A non-invasive system for detection of explosives and contraband
in a vehicle includes at least one laser vibrometer for measuring
vehicle vibrations at one or more points on the vehicle while the
vehicle is operating. One laser vibrometer can be sequentially
directed to various points on the vehicle according to a
predetermined single point or pattern. Or, a plurality of laser
vibrometers could be used to simultaneously illuminate the vehicle.
After measurement, the vehicle vibrations are compared to a
database of reference vibrations, which that were taken of similar
vehicles that were known to be contraband-free. The measured
vibrations are compared to the vibrations pattern for the same type
of vehicle. If the vibration patterns exhibit differences in
frequency peaks that exceed predetermined parameters, the system
alerts the operator. A more detailed inspection of the vehicle can
then be accomplished.
Inventors: |
Cottrell; Dana; (El Cajon,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cottrell; Dana |
El Cajon |
CA |
US |
|
|
Assignee: |
United States of America as
Represented by the Secretary of the Navy
|
Family ID: |
48701415 |
Appl. No.: |
12/329726 |
Filed: |
December 8, 2008 |
Current U.S.
Class: |
702/188 ;
340/540; 73/655 |
Current CPC
Class: |
G01H 9/00 20130101; G01H
3/00 20130101 |
Class at
Publication: |
702/188 ; 73/655;
340/540 |
International
Class: |
G01D 5/26 20060101
G01D005/26; G08B 21/00 20060101 G08B021/00; G06F 15/00 20060101
G06F015/00 |
Goverment Interests
FEDERALLY-SPONSORED RESEARCH AND DEVELOPMENT
[0001] This invention (Navy Case No. 099153) is assigned to the
United States Government and is available for licensing for
commercial purposes. Licensing and technical inquiries may be
directed to the Office of Research and Technical Applications,
Space and Naval Warfare Systems Center, Pacific, Code 2112, San
Diego, Calif., 92152; voice 619-553-2778; email T2@spawar.navy.mil.
Claims
1. A system for inspecting operating vehicles at a security
checkpoint, said checkpoint having a desired throughput and a
threat level, said vehicles having at least one compartment, said
system comprising: at least one means for measuring vehicle
vibrations generated by said compartment, said vehicle vibrations
being caused the operation of said vehicle, said vehicle vibrations
being measured from outside of said vehicle, said vehicle
vibrations having a plurality of vehicle frequency spectral peaks
and a vehicle low frequency band; a database of predetermined
reference vibrations, said reference vibrations corresponding to
said vehicles having said compartments that have not been modified,
said reference vibrations being caused by the operation of said
vehicles, said reference vibrations having a plurality of reference
frequency spectral peaks and a reference low frequency band; a
processor for comparing said vehicle vibrations to said reference
vibrations for detecting an anomaly in said non-machinery
components, said anomaly being deemed to exist when said vehicle
frequency spectral peaks and said reference frequency spectral
peaks differ more than a predetermined amount, and when said
vehicle low frequency band amplitude is less than said reference
low frequency band by a predetermined amount; and, said processor
adjusting said spectral peak predetermined amount and said
frequency band predetermined amount according to said throughput
and said threat level.
2-6. (canceled)
7. A method for non-invasive inspection of operating vehicles at a
security checkpoint, said checkpoint having a desired throughput
and a threat level, said vehicles having at least one compartment,
said method comprising the steps of: A) establishing a database of
reference vibrations corresponding to said vehicles, said reference
vibrations having emanated from the exterior surface of said
compartment, said reference vibrations being caused by the
operation of said vehicles, said reference vibrations further
having a plurality of reference frequency spectral peaks and a
reference low frequency band; corresponding to said compartment
that has not been modified; B) measuring vehicle vibrations
corresponding to said vehicles, and further emanating from the
exterior surface of said compartment, said vehicle vibrations being
caused by the operation of said vehicle, said vehicle vibrations
further having a plurality of vehicle frequency spectral peaks and
a vehicle low frequency band; C) comparing said vehicle vibrations
to said reference vibrations; D) deeming said vehicle as having an
anomaly in at least one compartment when the results of said step
C) indicate that said vehicle low frequency band is less than said
reference low frequency band by a predetermined amount, and that
said vehicle frequency spectral peaks differ from said reference
frequency spectral peaks by a predetermined amount; and D1)
adjusting said frequency band predetermined amount and said
spectral peak predetermined amount according to said desired
throughput and said threat level.
8. (canceled)
9. (Canceled)
10. (Canceled)
11. The method of claim 7, further comprising the step of: E)
alerting the system operator.
12. (canceled)
Description
FIELD OF THE INVENTION
[0002] This disclosure relates to detection of explosives and
contraband. More particularly, this disclosure relates to the use
of non-invasive methods, which include laser vibrometers for
detection of explosives and contraband located in hidden
compartments of vehicles.
BACKGROUND OF THE INVENTION
[0003] The detection of contraband and explosives in vehicles is of
paramount importance, not only to the military, but to society in
general. As new detection methods emerge, smugglers continue to
find new and more creative places to establish hiding places in
vehicles; these hiding places are, by design, not easily accessed
for inspection. One example of such a hiding place is to establish
a void in a vehicle's fuel tank. Absent specialized equipment, it
would be very difficult to search the fuel tank of each vehicle for
special voids.
[0004] Additionally, it should be appreciated that, when deciding
how thoroughly vehicles should be searched, operational security
considerations must be balanced with the inconvenience of such a
thorough search. In times of extremely high threat conditions, it
may be feasible to search all vehicles thoroughly. But for other,
lesser threat levels, it may not be feasible to search tanks and
compartments of each and every vehicle passing through a
checkpoint, because it takes too long to accomplish that
search.
[0005] On the one hand, vehicles can be x-rayed. However, x-ray
machines are extremely expensive, few in numbers, time consuming,
and quite inconvenient. Dogs can be used to sniff out contraband,
but they are of limited use and smugglers are finding ways to
defeat this method of detection. Neutron beam detectors have been
used, but because of safety issues, operators prefer not to use
these devices.
[0006] In view of the above, what is desired is a system and method
for searching voids and compartments of vehicles that is
non-invasive, that can be quickly accomplished at a checkpoint
having a high throughput of vehicles, and that is safe for the
operator and relatively easy to use.
SUMMARY OF THE INVENTION
[0007] A system for detection of explosives and contraband in a
vehicle, can include at least one laser vibrometer for measuring
vehicle vibrations. The laser vibrometer measures the vibration
levels of an operating vehicle at various points on the vehicle.
For example, the laser vibrometer can be directed to various points
of a vehicle fuel tank to measure the vibrations. One laser
vibrometer can be used, with the laser vibrometer being
sequentially directed to predetermined points on the vehicle. Or, a
plurality of laser vibrometers could be used, with each laser
vibrometer illuminating the vehicle simultaneously.
[0008] After measurement, the vehicle vibrations are compared to
database of reference vibrations. The database comprises vibration
"footprints" that were taken of vehicles that were known to be
contraband-free. The measured vibrations are compared to the
vibrations pattern for the same type (make and model) of vehicle.
If the vibration pattern is "different", then the system can alert
the operator, who can subsequently conduct a more detailed
inspection of the vehicle. The differences could be a shift in
number and/or frequency of observed vibrations peaks; or, the
differences could be due to the differences in amplitudes between
the measured vibration peaks and the amplitude of the peaks in the
reference vibration pattern for that vehicle.
[0009] For the methods of the present invention, a database of
reference vibrations can be established. The database is
representative of vibration patterns of vehicles that are known to
be contraband-free. The methods can also involve the step of
measuring the vehicle vibrations of an operating vehicle. The
vibrations can be measured by simultaneously illuminating the
vehicle at predetermined points with a plurality of laser
vibrometers, or alternatively by sequentially illuminating the
vehicle at predetermined points with a single laser vibrometer, to
measure the vehicle vibrations. After measurement, the vehicle
vibrations are compared to reference vibration for that same make
and model of vehicle. If the differences in vibrations exceed a
predetermined amount, the vehicle is deemed to be carrying
contraband and a more detailed inspection of the vehicle is
warranted.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The novel features of the present invention will be best
understood from the accompanying drawings, taken in conjunction
with the accompanying description, in which similarly-referenced
characters refer to similarly-referenced parts, and in which:
[0011] FIG. 1 is a block diagram of the explosives and contraband
detection system according to several embodiments of the present
invention.
[0012] FIG. 2 is a block diagram of an alterative embodiment for
the laser vibrometer for the system shown in FIG. 1;
[0013] FIG. 3 is a graph of vibration responses, which depicts the
shift in vibration characteristics for a unmodified fuel tank of a
vehicle when compared to a fuel tank that has had a secret
compartment welded therein; and,
[0014] FIG. 4 is a block diagram that is representative of methods
according to several embodiments of the present invention.
DETAILED WRITTEN DESCRIPTION OF THE EMBODIMENTS
[0015] Referring initially to FIG. 1, the explosives and contraband
detection system in accordance with several embodiments of the
invention is shown and is generally designated by reference
character 10. As shown, system 10 includes an accelerometer 12 for
measuring vibrations 14 of an operating vehicle 16. The
accelerometer is in communication with a processor 18 and sends the
measured vibrations 14 to processor 18 during operation of the
system. This can be accomplished via a hardwired data link if
processor 18 is proximate accelerometer 12, or the vibration
measurement data can be sent via wireless connection if the
processor is located remotely from accelerometer 12.
[0016] The processor 18 is also connected to a database 20.
Database 20 contains a multitude of representative vibration
patterns from vehicles that are known to be contraband-free or free
of hidden compartments. Explosives or contraband material packed
into a hidden compartment will dampen out the vibrations in the
sides of the compartment. If a compartment of a vehicle such as a
gas tank 22 is modified, changes in vibration frequencies and
levels will occur. An accelerometer or laser vibrometer can measure
the vibrations of the compartment in question.
[0017] For operation, accelerometer 12 measures the vehicle
vibrations 14 and transmits the resulting vibration data to
processor 18. The processor receives the measured vibrations from
the accelerometer 12. The processor accesses database 20 for
reference vibrations for the same type of vehicle; the processor
then compares the measured vibrations to reference vibrations. If
the differences exceed predetermined limits, then the processor can
cause a visual/audible alarm at the display 24, which is connected
to the processor 18. In response, the checkpoint operator (not
shown) can direct the vehicle to a more detailed secondary
inspection.
[0018] The system 10 shown in FIG. 1 can exist in several
configurations. For example, in the case where a vehicle checkpoint
is fixed, the accelerometer can be fixed in place at the
checkpoint. Alternatively, a hand held accelerometer can be used.
In either case, the accelerometer can be hardwired to a fixed
processor; or, the accelerometer can have a wireless connection to
a portable processor, such as a laptop of similar type of
processor.
[0019] In several embodiments of the invention, a laser vibrometer
26 can be used as the accelerometer to measure vehicle vibrations
when it is more convenient to measure and transmit vibration data
in an extremely timely manner. For the configuration shown in FIG.
1, a single laser vibrometer can be used, and the single laser
vibrometer can be sequentially directed at a predetermined point or
plurality of points that may or may not define a grid. For this
embodiment, the processor can also function as a control to
selectively activate/deactivate the single laser vibrometer over
each successive point in the grid. Exemplary measurements points on
the vehicle 16 to be searched include areas on a vehicle where
hidden compartments are likely to exist, such as the fuel tank, or
the vehicle door panels (vibrations in other areas can also be
measured).
[0020] An alternative embodiment of the invention is shown in FIG.
2. As shown, a plurality of laser vibrometers 26a-26n can be used
to simultaneous illuminate vehicle 16 at predetermined points. The
activation/deactivation of the laser vibrometer can be accomplished
by processor 18, which in this embodiment would have an additional
function as a controller for the laser vibrometers. Specialized
fiber optic probes can allow for the examination of locations that
are difficult to access. It should also be appreciated that any
accelerometer that is capable of measuring vehicle vibrations could
be used. For example, piezoelectric, magnetic induction or optical
accelerometers could also be used.
[0021] The aforementioned database 20 includes a statistical
average of data collected for several vehicles of the same make and
model. The vehicles could be chosen according to historical data of
previous use for carrying of contraband (i.e., certain types of
vehicles are used for carrying of contraband much more often than
others). Collected data can be compared to a database of
measurements typical for these preselected vehicles. A scanning
vibrometer can measure entire surfaces. This method is quite
comprehensive and generates a lot of vibration data. Such measured
data can be more difficult to interpret and compare to a data base,
so the amount of measured vibrations should be commensurate with
the processing capabilities of the system processor 18.
[0022] FIG. 3 is illustrative of the differences in vibration
patterns between modified and unmodified vehicles, and how those
differences in vibration patterns can be exploited to determine
whether a vehicle is carrying contraband. Referring now to FIG. 3,
the unmodified vehicle pattern 300 for a gas tank of Volkswagen
Beetle that is known to be free of contraband and hidden
compartments is compared to the vibration pattern 302 for a gas
tank that was taken from a Volkswagen Beetle, but with a hidden
compartment that has been welded therein. As shown in FIG. 3,
unmodified pattern 300 has strong peak 304 at 540 Hz and another
strong peak 306 at 1450 Hz; these peaks are not in modified pattern
302. Modified vibration pattern 302 has a strong peak 308 at 1200
Hz and another peak 310 at 1900 Hz; these peaks are not present at
these frequencies for the unmodified vibration pattern 300 for the
unmodified gas tank.
[0023] Given the data cited in FIG. 3, a processor 18, receiving
the measured vibrations as an input and accessing the reference
vibrations, can distinguish between a modified tank and an
unmodified tank. In sum, a gas tank with a false compartment can be
distinguished from one which has not been tampered with by analyses
of: (1) Specific spectral peaks, (2) General spectral trends such
as suppression of low frequency bands, and (3) Phase shifts of
spectral peaks. One of these characteristics could be analyzed to
determine the presence/absence of a hidden compartment, or all
three of these characteristics could be used to deem a vehicle as
containing a hidden compartment.
[0024] Referring now to FIG. 4, a block diagram illustrating the
methods of several embodiments of the invention is shown. As shown,
the method includes the initial step to establish a data base of
reference vibration, as indicated for block 402. The database
contains reference vibrations for vehicles of interest that are
known to be free of contraband and free of hidden compartments.
[0025] The methods according to several embodiments of the present
invention further include the step of measuring the vehicle
vibrations for the vehicle of interest, as indicated by block 404.
The vibration measurements can be carried by a single laser
vibrometer that is sequentially directed at a predetermined point
(s) on the vehicle that may or may not define a grid, or the
vibration measure can be accomplished by a grid of laser vibrations
that are simultaneously activated to illuminate the vehicle and
obtain vibration measurements.
[0026] After measurement, the vehicle vibrations are compared to
the reference vibrations stored in the aforementioned database, as
indicated by step 406. The comparison step compares the reference
vibrations to the vehicle vibrations and looks for differences in
specific spectral peaks, suppression of low frequency bands and/or
phase shifts in the spectral peaks as detailed above. It should be
appreciated that the difference parameters can be adjusted
according to prior intelligence on the threat of contraband whether
generalized or for a specific vehicle/type of vehicle, the vehicle
throughput of the checkpoint (and the attendant need to minimize
checkpoints) and the capabilities of the processor.
[0027] If the differences exceed predetermined limits, the system
deems the vehicles as carrying contraband, as indicated by step
408, and alerts the operator if needed, as indicated by block 410.
The predetermined can be adjusted to the needs of the user and the
operational environment. On the one hand, if the security
checkpoint vehicle traffic is relatively light and the threat level
is deemed to be very high. The predetermined difference in
parameters can be reduced, but at the expense of an increase false
alarm rate. On the other hand, if vehicle traffic at the checkpoint
is heavy, it may be desired to relax the predetermined parameters
to minimize the false alarm rate. In this manner, vehicles such as
gas trucks that can carry large amounts of explosives can be
quickly inspected on sight; any future changes in measurements on
the vehicle that fall out of the norm or appear suspicious would
serve to alert the checkpoint operator.
[0028] The use of the terms "a" and "an" and "the" and similar
references in the context of describing the invention (especially
in the context of the following claims) is to be construed to cover
both the singular and the plural, unless otherwise indicated herein
or clearly contradicted by context. The terms "comprising,"
"having," "including," and "containing" are to be construed as
open-ended terms (i.e., meaning "including, but not limited to,")
unless otherwise noted. Recitation of ranges of values herein are
merely intended to serve as a shorthand method of referring
individually to each separate value falling within the range,
unless otherwise indicated herein, and each separate value is
incorporated into the specification as if it were individually
recited herein.
[0029] All methods described herein can be performed in any
suitable order unless otherwise indicated herein or otherwise
clearly contradicted by context. The use of any and all examples,
or exemplary language (e.g., "such as") provided herein, is
intended merely to better illuminate the invention and does not
pose a limitation on the scope of the invention unless otherwise
claimed. No language in the specification should be construed as
indicating any non-claimed element as essential to the practice of
the invention.
* * * * *