U.S. patent application number 12/729981 was filed with the patent office on 2010-09-23 for light based projectile detection system for a virtual firearms training simulator.
Invention is credited to Bobby Hsiang-Hua Chung, Brian Ronald Vaceluke.
Application Number | 20100240015 12/729981 |
Document ID | / |
Family ID | 42737974 |
Filed Date | 2010-09-23 |
United States Patent
Application |
20100240015 |
Kind Code |
A1 |
Chung; Bobby Hsiang-Hua ; et
al. |
September 23, 2010 |
Light Based Projectile Detection System for a Virtual Firearms
Training Simulator
Abstract
A light based projectile detection system for use with a firearm
and a virtual firearms training simulator includes a self-sealing
screen having a proximal side and a distal side. A scenario
projector transmits a simulation onto the proximal side, and a
light source faces the distal side. The light source selectively
projects light onto the distal side of the screen when the firearm
is shot, such that light from the source traverses the screen after
contact by a projectile. A camera monitors the light traversing the
aperture created by the projectile to determine and associate the
position of impact and transmit that information to a scenario
computer. The system may include an audio detection circuit to
monitor the sound generated by the firearm and transmit a signal to
a flash controller to cause the light source to illuminate. The
screen will then re-seal around the hole so that the light no
longer traverses the screen.
Inventors: |
Chung; Bobby Hsiang-Hua;
(Atlanta, GA) ; Vaceluke; Brian Ronald;
(Lawrenceville, GA) |
Correspondence
Address: |
SMITH, GAMBRELL & RUSSELL
SUITE 3100, PROMENADE II, 1230 PEACHTREE STREET, N.E.
ATLANTA
GA
30309-3592
US
|
Family ID: |
42737974 |
Appl. No.: |
12/729981 |
Filed: |
March 23, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61162498 |
Mar 23, 2009 |
|
|
|
Current U.S.
Class: |
434/21 |
Current CPC
Class: |
F41J 5/10 20130101; F41G
3/2694 20130101 |
Class at
Publication: |
434/21 |
International
Class: |
F41G 3/26 20060101
F41G003/26 |
Claims
1. A light based projectile detection system for use with a firearm
firing a projectile and a virtual firearms training simulator
having a scenario projector, a camera, and a scenario computer,
said projectile detection system comprising: a self-sealing screen
having a proximal side and a distal side, the scenario projector
transmitting a simulation onto said proximal side; and a light
source facing said distal side of said screen to selectively
project light onto said distal side of said screen; wherein light
from said light source traverses said self-sealing screen to be
monitored by the camera at the point of contact of the projectile
with said self-sealing screen.
2. The projectile detection system as described in claim 1, further
comprising: a sensor generating a signal corresponding to the
operation of the firearm; and a flash controller in electrical
communication with said sensor and said light source to illuminate
said light source corresponding to the firing of the firearm.
3. The projectile detection system as described in claim 1 further
comprising a housing supporting said screen, said housing
controlling the distribution of light from said light source
proximate said screen.
4. The projectile detection system as described in claim 3 wherein
said light source includes a xenon flash.
5. The projectile detection system as described in claim 3 further
comprising a reflective panel mounted in said housing, said light
source positioned between said reflective panel and said
screen.
6. A training system to detect impact coordinates of one or more
projectiles fired by one or more firearms, the system comprising: a
self-sealing screen having a proximal side and a distal side; a
light source facing said distal side of said screen to selectively
project light onto said distal side of said screen; a simulation
computer generating a simulation; a projector in electrical
communication with said computer, said projector broadcasting a
simulation on said proximal side of said screen; a camera in
electrical communication with said computer to detect a light pulse
on said screen; wherein light from said light source traverses said
self-sealing screen to be monitored by said camera at the point of
contact of the projectile with said self-sealing screen upon impact
of the projectile through said screen.
7. The training system as described in claim 6 further comprising:
means for generating a signal corresponding to the firing of the
firearm; and means for controlling the illumination of said light
source corresponding to said signal.
8. The training system as described in claim 7 wherein said signal
generating means comprises an audio detection circuit positioned
proximate the firearm, said audio detection circuit including a
microphone to monitor the sound of the firing of the firearm.
9. The training system as described in claim 7 wherein said control
means comprises a flash controller in electrical communication with
said audio detection circuit and said light source to illuminate
said light source corresponding to the signal generated by said
audio detection circuit.
10. The training system as described in claim 7 further comprising
a housing supporting said screen, said housing controlling the
distribution of light from said light source proximate said
screen.
11. The training system as described in claim 10 further comprising
a reflective panel mounted in said housing, said light source
positioned between said reflective panel and said screen.
12. The training system as described in claim 7 wherein said light
source comprises a xenon flash.
13. A method for determining the position of impact on a target of
a projectile launched by a firearm, said method comprising the
steps of: a) providing a self-sealing screen having a proximal side
and a distal side; b) generating the target on the proximal side of
said screen using a projector in electrical communication with a
simulation computer; c) monitoring the proximal side of the screen
for a light pulse with a camera in electrical communication with
said simulation computer; d) selectively illuminating said distal
side of said screen with a light source; e) generating a light
pulse in said screen with said light source when the projectile
traverses said screen; and f) registering the point of contact of
the projectile with said screen with said camera connected to said
simulation computer.
14. The method as described in claim 13 wherein step d) further
comprises the steps of: generating a signal corresponding to the
discharge of the projectile from the firearm; and transmitting said
signal to said light source to selectively illuminate said distal
side of said screen.
15. The method as described in claim 14 further comprising the step
of monitoring the sound of the discharge of the firearm using a
audio detection circuit.
16. The method as described in claim 13 further comprising the step
of: supporting said screen and said light source in a housing to
control the distribution of light from said light source proximate
said screen.
17. The method as described in claim 16 further comprising the step
of: distributing light from said light source along said distal
side of said screen with a reflective panel mounted in said
housing, said light source positioned between said reflective panel
and said screen.
18. The projectile detection system as described in claim 13
further comprising the step of: providing a xenon flash for said
light source.
19. The projectile detection system as described in claim 2,
wherein said sensor comprises an audio detection circuit positioned
proximate the firearm, said audio detection circuit having a
microphone to monitor the sound of the firing of the firearm.
Description
CROSS REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This application claims priority from co-pending U.S.
Provisional Application Ser. No. 61/162,498, filed on Mar. 23,
2009, said application being relied upon and incorporated herein by
reference.
FIELD OF INVENTION
[0002] The present invention relates to a system and method for
determining the actual coordinates of a projectile impact in a
screen and associating the point of impact with a firearms training
simulation.
BACKGROUND OF THE INVENTION
[0003] A typical virtual firearms training simulator uses simulated
weapons that do not fire real bullets to train students on the
proper handling of a weapon during a simulated real life scenario.
The training scenario includes a video, digital animation, or other
virtual scenario of one or more situations requiring the user to
react quickly and decisively, such as a hostage scenario, terrorist
attack, or general malfeasance. This scenario is projected onto a
screen using a video projector, with the scenario being controlled
by a simulation computer that also detects the point of aim at the
instance the student pulls the trigger of the simulated weapon. The
simulated weapon is equipped with either an invisible or visible
laser that "fires" a laser pulse when the trigger is pulled. A
camera, in electrical communication with the simulation computer,
detects this pulse of light, and transmits the impact coordinates
to the simulation computer. The simulation computer then determines
the location of the hit relative to the scenario being broadcast by
matching the coordinate system of the camera to the coordinate
system of the projected image or target.
[0004] A drawback to this system is that the simulated weapon
operated by the user often simply generates a laser pulse to
imitate the firing of the weapon, which does not produce a
realistic experience for the user. That is, the simulated weapon
typically does not have the feel of an actual firearm, and often
does not produce recoil action, or produces unrealistic recoil
action for the user, such that the simulation lacks credibility for
the user. Consequently, trainees that are not used to extensive
target practice with live firearms may be disadvantaged when
required to handle firearms in combat situations.
[0005] A variant of this virtual firearms training simulator is one
that detects real bullets fired from an actual live weapon. Since a
bullet is not a pulse of light, the camera detection method
described above may not seem practical to use. Rather, several
alternative detection methods have been developed as an add-on to
an existing simulator's laser detection system. They include
detection of the visual image of the bullet as it passes an array
of sensors, detection of the heat signature of the bullet as it
penetrates the screen, detection of the acoustical waves generated
by the bullet as it passes an array of acoustic sensors, or
detection of the hole that the bullet makes when penetrating a
screen material such as paper. While all of these methods may work
to some degree, none of them are performed within desired
parameters, such as at a low financial cost and having a high
degree of accuracy.
BRIEF SUMMARY OF THE INVENTION
[0006] A light based projectile detection system for a firearm and
a virtual firearms training simulator is described herein. The
light based projectile detection system includes a self-sealing
screen having a proximal side and a distal side. A scenario
projector transmits a simulation onto the proximal side, and a
light source (such as a flash) faces the distal side. The light
source selectively projects light onto the distal side of the
screen when the firearm is shot, such that light from the source
traverses the screen after contact by a projectile. A camera
monitors the light traversing the aperture created by the
projectile to determine and associate the position of impact and
transmit that information to a scenario computer.
[0007] The system may include an audio detection circuit to monitor
the sound generated by the firearm and transmit a signal to a flash
controller to cause the light source to illuminate. The screen will
then re-seal around the hole so that the light no longer traverses
the screen.
[0008] The system may additionally include a housing to support the
screen, with the light source surrounded by the housing and screen
to control the distribution of light from said light source. In
such an embodiment, a reflective panel (such as paper with foil on
one side) may be mounted in said housing diagonally, with the light
source positioned between the reflective panel and the screen. This
arrangement will project light directly onto the distal side of the
screen as well as onto the reflector panel, which will assist in
evenly projecting light on the distal side of the screen.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a block diagram of the light based projectile
detection system for a virtual firearms training simulator;
[0010] FIG. 2 is a second block diagram of the light based
projectile detection system for a virtual firearms training
simulator of FIG. 1, the diagram showing the impact of a projectile
with a screen; and
[0011] FIG. 3 is a perspective view of the screen and light
assembly incorporated into the system illustrated in FIGS. 1 and
2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] Referring to FIGS. 1-3, a light based projectile detection
system 10 is illustrated. The light based projectile detection
system 10 is able to monitor the impact of a projectile 18 fired by
an actual firearm 16 on a self-sealing screen 14 using a laser
detection system 12 similar to those described above and as used in
a typical laser-based virtual firearms training simulator known in
the art.
[0013] More specifically, the laser detection system 12 includes a
scenario projector 20 and a camera 22 that are both in electrical
communication with a simulation or hit detect computer 24. The
projector 20 may include any type of image-generating device, and
receives a simulation scenario from the hit detect computer 24. The
projector 20 will then broadcast that scenario on one or more
self-sealing screens 14. In contrast, the camera 22 monitors the
self-healing screen 14 for a light or laser pulse, which will
correspond to the point of impact of the projectile 18 fired in
during the simulation projected on the screen 14. That is, the
laser detection system 12 will monitor the actual live fire of the
weapon 16 to determine the impact position of a fired projectile
18, such as a bullet or slug, through the screen 14 during
simulation scenarios projected on the screen 14. Once the light
pulse is detected, the camera 22 will transmit the coordinates of
the impact to the hit detect computer 24. The computer 24 includes
software that will be able to compute the impact coordinate
relative to predetermined screen coordinates relative to the
projected target.
[0014] To leverage the laser detection system 12 to determine the
bullet position of impact on the screen 14, the bullet 18 must
generate a pulse of light at the specific location L1 where the
bullet 18 impacts the screen 14 after being fired by the weapon 16.
To generate this pulse of light, the projection screen 14 of the
bullet detection system 10 is made of a self-healing elastomeric
material, such as a natural gum rubber or other similar substance
known in the art. The screen 14 has a proximal side 14p and an
opposite distal side 14d. The proximal side 14p faces and is
closest to the laser detection system 12, while the distal side 14d
opposite the proximal side 14p faces and is closest to a light
source 26. The light source 26 outputs wavelengths of light 28 that
can be detected by the same camera 22.
[0015] When a projectile 18 penetrates the surface of the screen 14
at location L1 (see FIG. 1), it will create a hole H1 at the
location L1 that creates a light valve to allow light 28 to travel
through the screen 14 (see FIG. 2). After a period of time, the
self-healing material of the screen 14 will re-seal the hole H1 so
that the camera 22 will no longer monitor any light 28 through the
screen 14. As a result, the brief exposure of light 28 through the
light valve H1 in the screen 14 will simulate a light pulse.
Because the temporary hole H1 is the position L1 of the bullet 18
at impact, the accuracy for monitoring the light through the light
valve H1 by the camera 22 is the same as the laser pulse detection
(as described above). Any calibration algorithm used by the hit
detect computer 24 to match the coordinate system of the camera 22
to the coordinate system of the projected simulation of the hit
detect computer 24 as projected by projector 20 may be used in the
present system; that is, the calibration algorithm used by the
simulation hit detect computer 24 to match the coordinate system of
the camera 22 to the coordinate system of the projected simulation
of the hit detect computer 24 will remain the same whether one uses
a laser pulse in prior simulation systems or shoots a real bullet
18 in the training scenario of the present system.
[0016] A prototype of the design integrated with typical virtual
small arms training simulator is illustrated in FIG. 1. This
prototype was tested for accuracy in matching the contact of the
bullet 18 with the scenario, and the results were accurate within 1
to 3 mm, which is very similar to the laser-based system. It was
determined the best way to get the most amount of light 28 for the
camera 22 to detect the bullet 18 passing through the screen was to
use a xenon flash 26 facing the distal side 14d of the screen 14
that is selectively illuminated instead of a continuous light
source. A xenon flash was selected for its desirable properties in
light intensity while generating relatively lower heat. As a
result, a flash triggering system 30 is connected to the light
source 26 to ensure proper timing of the light 28 with the firing
event of the weapon 16.
[0017] The flash triggering system 30 includes an audio detection
circuit 32 or other means for generating a signal corresponding to
the firing of the firearm 16 in electrical communication with a
flash/trigger controller 34. The audio detection circuit 32 may be
any known in the art, such as a circuit including a microphone for
converting audio energy (sound waves) into an electrical signal.
Other sensors or means for generating a signal corresponding to the
firing of the firearm 16 may be incorporated in the system 30 to
monitor the operation of the firearm 16. Such sensors include, but
are not limited to, a photocell sensor for monitoring the muzzle
flash of the bullet 18 leaving the firearm 16 or a sensor for
measuring the vibration of the firearm 16 (such as an accelerometer
or a piezoelectric sensor) when fired. Thus, the flash triggering
system 30 is able to monitor any element associated with the firing
of the firearm 16 (sound, vibration, light, or other features
associated with the operation of the firearm 16) to generate a
desired signal to transmit to the controller 34 upon the firing of
the weapon 16. Similarly, the flash/trigger controller 34 may be a
conventional microcontroller that is in electrical communication
with the audio detection circuit 32 and the light source 26. In the
illustrated embodiment, the audio detection circuit 32 is
positioned somewhat near the weapon 16, and detects the sound
associated when the weapon 16 is initially shot. The audio
detection circuit 32 thereby transmits a signal to the flash
controller 34 corresponding to the timing of the weapon 16 being
fired.
[0018] The flash controller 34, which is in electrical
communication with the light source 26, will use the signal
transmitted from the audio detection circuit 32 to further send a
signal triggering a bank of facing the distal side 14d of the
screen 14. The xenon flash bulbs 26 will therefore be illuminated
at the approximate time when the bullet 18 penetrates through the
self-healing rubber front surface 14p. This is accomplished by
having the controller 34 turn the flash bulbs 26 on after a
pre-determined time delay to ensure the camera 22 will detect or
view the light 28 while there is a bullet hole H1 in the screen 14.
This time delay will vary depending on the speed of the bullet 18
used and the distance that the firearm 16 is from the screen
14.
[0019] Looking to FIG. 3, the screen 14 may be mounted in a housing
or frame 36 (one side of the housing 36 is removed to view the
screen 14). The housing 36 and screen 14 define a casing that
surrounds the light source 26, such that the housing 36 and screen
14 will contain all light produced by light source 26 until the
screen 14 is pierced by a bullet 18. Although the present
rectangular housing 36 is illustrated, other frames may be
implemented for the housing 36 as desired by the user. Furthermore,
a reflector panel 38 may be diagonally mounted within the housing
36 above the light source 26, such that the light source 26 is
positioned between the reflector panel 38 and the screen 14. The
reflector panel 38 may be made of a sheet of paper with foil on a
side nearest the light source 26 or some other similar material
that has a high reflectivity to effectively reflect and distribute
the light produced by the light source 26. The light source 26 will
therefore project light directly onto the screen 14 as well as onto
the reflector panel 38 to project light evenly on the distal side
14d of the screen 14.
[0020] As noted above, a prototype using xenon flash bulbs 26 was
developed and tested to work as expected with accuracy to be within
1 to 3 mm.
[0021] Without knowing the properties of the rubber screen 14 (such
as the stretch or hardness), an assumption is made that there is a
finite amount of time before the screen 14 will re-seal itself
(return back to its original shape) depending on the distance and
failure point of the stretch in the screen 14. A further assumption
of a worst case condition is that the re-seal time is zero (that
is, that the screen 14 is a perfect material that reseals
instantly). In other words, the screen 14 is sealed as soon as the
bullet or slug 18 passes through the screen 14. It is also assumed
that the only time "light" 28 is allowed through the screen 14 is
while the slug 18 is penetrating the screen 18 (i.e., the initial
hole H1 that the slug 18 makes is bigger than the slug 18 to allow
this light 28 to come through as the slug 18 is passing through.)
To determine how much light 28 is directly related to the speed of
the slug 18 and how long the "light valve" is left on (that is, how
long light passes through the screen 14 before it reseals), the
following equation should be used:
[0022] Light valve on time=[(length of slug+thickness of
screen+distance the screen stretch before initial
penetration)/speed of slug]+[resealing time once the slug 18
passes], the following measurements are determined.
[0023] Assuming that the minimum distance of stretch in the screen
14 is half of the diameter of the slug 18 (but is most likely more)
and is dependant of speed of the slug 18 and material property of
the screen 14, 5 mm as the screen thickness, 0 sec for the
resealing time once the slug passes (this is somewhat dependant on
how far the material is stretched and the screen material
property), the following calculations are made:
[0024] A typical spec for a 9 mm NATO ball is: Speed of slug range
from 950 ft/s to 1300 ft/s with a slug length of 0.610'' or 15.5
mm.
[0025] A typical specification for a 5.56 mm, ball is: Speed of
slug is 3250 ft/s with the slug length of 19.3 mm to 23 mm.
[0026] So minimum light valve on time for a 9 mm slug is
(15.5+5+4.5)/(1300*304.8)=63.1 .mu.sec, and the minimum light valve
on time for a 5.56 mm is (19.3+5+2.28)/(3250*304.8)=26.8
.mu.sec.
[0027] In a charged coupled device (CCD) in the camera 22 for
capturing images, there is a photoactive region (an epitaxial layer
of silicon), and a transmission region made out of a shift
register. An image is projected by a lens on the capacitor array
(the photoactive region), causing each capacitor to accumulate an
electric charge proportional to the light intensity at that
location. The exposure time for the light valve H1 is calculated at
a minimum from 26.8 to 63.1 .mu.sec (based on the calculations for
the above-noted assumptions). Consequently, it is possible to
detect the charge if the intensity is large enough using the CCD
sensor as long as the noise level in the CCD sensor is not larger
than the charge. Since this is really an absolute minimum in an
ideally perfect situation, the actual time the light valve H1 will
be open will be greater, if not significantly greater.
[0028] In addition, there is a blanking time between the shifting
of data out of the register where the CCD sensor cannot accumulate
charges. This blanking needs to be as small as possible. The
current camera 22 has about a 2 msec blank time. This is more of a
function determined by the camera manufacturer. For example, the
current camera 22 being evaluated for the system 10 has a blank
time between frames of 35 .mu.sec out of the box and can be
adjusted even lower.
[0029] The calculations support the theory that the capabilities of
CCD sensor can allow it to detect a bullet slug 18 traveling
through a re-sealable rubber screen 14 with a back-lit light source
26.
[0030] The design above was initially tested using a rubber live
fire screen as a proof of concept, some incandescent light bulbs, a
standard 100 D-P (small arms virtual system) with the standard hit
camera 22 and a filter (an infrared filter used to monitor the
desired light) and a TV monitor. The back side or distal side 14d
of the screen 14 was lit using light bulbs totaling approximately
1000 watts, with the rear rubber screen removed so that only the
front rubber screen was separating the light 26 and the shooter.
The hit camera 22 was pointed on the screen 14 as usual and the TV
monitor connected to "see" the output of the hit camera 22. The
design was tested with both 9 mm and 5.56 mm rounds 18. In all
cases, the users were able to visually see the light 28 come
through the screen 14 momentarily before the screen 14 would reseal
after the slug 18 passed through.
[0031] The 5.56 slug 18 did leave a pinhole and did not completely
reseal like the 9 mm slug 18. A small piece of the screen 14 had
been torn off from the back or distal side 14d when the 5.56 mm
slug 18 was shot, which did not occur with the 9 mm. A momentary
faint blurry light appeared on the TV monitor indicating where the
slug 18 went through the screen 14, which showed that detection is
possible and, with the right combination of filters, camera, screen
material, and lighting source, it is possible to design a system to
detect the brief pulse of light 28 caused by the penetration of the
bullet slug 18.
[0032] A high speed camera was also used to determine the
approximate on time of the material (how long the light valve H1
appears to be open) once a 9 mm slug has penetrated the screen 18.
The frame rate of the camera was approximately 8000 frames per sec.
The hole H1 appeared to be open for at least 4 frames or 4/8000 or
0.5 msec which is more 9 times longer than calculated for the worst
case scenario. These test results further demonstrated that the
proposed device will operate as desired.
[0033] Having thus described exemplary embodiments of a LIGHT BASED
PROJECTILE DETECTION SYSTEM FOR A VIRTUAL FIREARMS TRAINING
SIMULATOR, it should be noted by those skilled in the art that the
within disclosures are exemplary only and that various other
alternatives, adaptations, and modifications may be made within the
scope of this disclosure. Accordingly, the invention is not limited
to the specific embodiments as illustrated herein, but is only
limited by the following claims.
* * * * *