|
|  Custom CD of patents similar to US4924507 : Real-time optical multiple object recognition and tracking system and
method - $19.95 |
| United States Patent | 4924507 |
| Link to this page | http://www.wikipatents.com/4924507.html |
| Inventor(s) | Chao; Tien-Hsin (Valencia, CA);
Liu; Hua-Kuang (South Pasadena, CA) |
| Abstract | System for optically recognizing and tracking a plurality of objects within
a field of vision. Laser (46) produces a coherent beam (48). Beam splitter
(24) splits the beam into object (26) and reference (28) beams. Beam
expanders (50) and collimators (52) transform the beams (26, 28) into
coherent collimated light beams (26', 28'). A two-dimensional SLM (54),
disposed in the object beam (26'), modulates the object beam with optical
information as a function of signals from a first camera (16) which
develops X and Y signals reflecting the contents of its field of vision. A
hololens (38), positioned in the object beam (26') subsequent to the
modulator (54), focuses the object beam at a plurality of focal points
(42). A planar transparency-forming film (32), disposed with the focal
points on an exposable surface, forms a multiple position interference
filter (62) upon exposure of the surface and development processing of the
film (32). A reflector (53) directing the reference beam (28') onto the
film (32), exposes the surface, with images focused by the hololens (38),
to form interference patterns on the surface. There is apparatus (16', 64)
for sensing and indicating light passage through respective ones of the
positions of the filter (62), whereby recognition of objects corresponding
to respective ones of the positions of the filter (62) is affected. For
tracking, apparatus (64) focuses light passing through the filter (62)
onto a matrix of CCD's in a second camera (16') to form a two-dimensional
display of the recognized objects. |
| |
|
Title Information  |
|
|
|
|
|
Drawing from US Patent 4924507 |
|
|
Real-time optical multiple object recognition and tracking system and
method |
|
|
|
|
|
| Publication Date |
May 8, 1990 |
|
|
|
|
|
| Filing Date |
February 11, 1988 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Title Information  |
|
|
References  |
|
|
| *references marked with an asterisk below are user-added references |
|
U.S. References |
|
|
| Add a new US reference: |
| | Reference | Relevancy | Comments | Reference | Relevancy | Comments | 3717415
|      Your vote accepted [0 after 0 votes] | | 3779492
|      Your vote accepted [0 after 0 votes] | | 4824191 Kato 359/19 Apr,1989 |      Your vote accepted [0 after 0 votes] | | 4731859 Holter 382/225 Mar,1988 |      Your vote accepted [0 after 0 votes] | | 4715683 Gregory 386/128 Dec,1987 |      Your vote accepted [0 after 0 votes] | | 4707135 Swain 356/457 Nov,1987 |      Your vote accepted [0 after 0 votes] | | 4637056 Sherman 382/211 Jan,1987 |      Your vote accepted [0 after 0 votes] | | 4573198 Anderson 382/211 Feb,1986 |      Your vote accepted [0 after 0 votes] | | 4556986 Craig 382/106 Dec,1985 |      Your vote accepted [0 after 0 votes] | | 4462046 Spight 348/94 Jul,1984 |      Your vote accepted [0 after 0 votes] | | 4449144 Suzuki 348/699 May,1984 |      Your vote accepted [0 after 0 votes] | | 4386848 Clendenin 356/5.01 Jun,1983 |      Your vote accepted [0 after 0 votes] | | 4376950 Brown 348/40 Mar,1983 |      Your vote accepted [0 after 0 votes] | | 4357676 Brown 708/816 Nov,1982 |      Your vote accepted [0 after 0 votes] | | 4303832 Ehrat 250/556 Dec,1981 |      Your vote accepted [0 after 0 votes] | | 4075604 Degasperi 382/165 Feb,1978 |      Your vote accepted [0 after 0 votes] | | 3786180 Macovski 348/40 Jan,1974 |      Your vote accepted [0 after 0 votes] | | | | | |
|
|
|
|
U.S. References |
|
|
Foreign References |
|
|
|
|
|
|
Foreign References |
|
|
Other References |
|
|
|
|
|
|
Other References |
|
|
|
|
|
References  |
|
|
|
|
|
|
|
|
|
|
|
Public's "Guesstimation" of Royalty Value
| |
|
|
|
|
|
|
|
|
|
|
|
|
Market Review  |
|
|
Technical Review  |
|
|
Claims  |
|
|
We claim:
1. Apparatus for optically simultaneously recognizing a plurality of
objects within a field of vision comprising:
(a) a source of a coherent collimated light beam;
(b) beam splitter means for splitting said light beam into an object beam
and a reference beam;
(c) two-dimensional spatial light modulation means disposed in said object
beam for modulating said object beam with optical information as a
function of signals connected to X and Y inputs thereof;
(d) television camera means for developing X and Y signals reflecting the
contents of its field of vision, said X and Y signals being connected to
said X and Y inputs of said two-dimensional spatial light modulation
means;
(e) hololens means disposed in said object beam subsequent to said
two-dimensional spatial light modulation means for focusing said object
beam at a plurality of focal points;
(f) planar film means disposed with said focal points on an exposable
surface thereof for forming a multiple position interference filter upon
exposure of said exposable surface and subsequent development processing
of said film means;
(g) means for directing said reference beam onto said exposable surface of
said planar film means to expose said exposable surface in combination
with images focused by said hololens means forming interference patterns
on said exposable surface; and,
(h) means for simultaneously sensing and indicating light passage through
respective ones of the positions of said multiple position interference
filter following development processing of said exposable surface whereby
simultaneous recognition of objects corresponding to respective ones of
said positions of said multiple position interference filter is affected.
2. The apparatus of claim 1 wherein:
said means for simultaneously sensing and indicating light passage through
respective ones of the positions of said multiple position interference
filter includes means for indicating light passage only if light passing
therethrough is above a pre-established threshold level corresponding to
object recognition.
3. The method of optically simultaneously recognizing individual
pre-defined ones of a plurality of objects within a field of vision
comprising the steps of:
(a) pre-defining the objects to be recognized by the steps of,
(a1) providing a controlled source of a coherent collimated light beam and
means for splitting the light beam into an object beam and a reference
beam;
(a2) disposing a two-dimensional spatial light modulator in the path of the
object beam to modulate the object beam with optical information as a
function of signals connected to X and Y inputs thereof;
(a3) providing a television camera to develop X and Y signals reflecting
the contents of its field of vision;
(a4) connecting the X and Y signals to the X and Y inputs of the
two-dimensional spatial light modulator;
(a5) disposing a hololens in the path of the object beam subsequent to the
two-dimensional spatial light modulator to focus the object beam at a
plurality of focal points in a plane;
(a6) disposing unexposed transparency-forming film with an exposable
surface thereof in the plane of the focal points;
(a7) providing means for directing the reference beam onto the exposable
surface of the film to expose the exposable surface in combination with
images focused by the hololens forming interference patterns on the
exposable surface;
(a8) placing an object to be recognized within the field of vision of the
television camera;
(a9) covering the exposable surface of the film except for one focal point
location thereof;
(a10) turning on the coherent collimated light beam to expose the exposable
surface of the film at the one exposed focal point location;
(a11) repeating steps (a8) through (a10) with different objects and focal
point locations to expose points of a multiple position interference
filter;
(a12) development processing the film to form the multiple position
interference filter; and thereafter,
(b) subsequently simultaneously recognizing the objects by the steps of,
(b1) disposing the multiple position interference filter with the points
thereof in the plane of the focal points;
(b2) operatively positioning means for simultaneously sensing and
indicating light passage through respective ones of the positions of the
multiple position interference filter;
(b3) directing the field of vision of the television camera on an area
containing objects to be recognized;
(b4) turning on the coherent collimated light beam to create only the
object beam with the contents of the field of vision of the television
camera dynamically impressed on the object beam by the two-dimensional
spatial light modulator; and,
(b5) monitoring the simultaneous sensing and indicating means for
indications of light passage through ones of the positions of the multiple
position interference filter whereby simultaneous recognition of objects
corresponding to respective ones of the pre-defined positions of the
multiple position interference filter is affected.
4. The method of claim 3 wherein:
said step of monitoring the simultaneous sensing and indicating means for
indications of light passage through ones of the positions of the multiple
position interference filter includes the step of indicating light passage
only if light passing through a position is above a pre-established
threshold level corresponding to object recognition.
5. The method of claim 4 and additionally comprising the step for tracking
the objects of:
focusing light passing through positions above said pre-established
threshold level onto a charge coupled device to create a two-dimensional
image of the field of view of the television camera and the recognized
objects therein whereby movement of the objects can be seen and visually
tracked.
6. Apparatus for optically simultaneously recognizing a plurality of
objects within a field of vision comprising:
(a) a laser producing a coherent laser beam;
(b) beam expanders and collimators positioned to transform said object beam
and said reference beam into coherent collimated light beams;
(c) a beam splitter disposed to split said laser beam into an object beam
and a reference beam;
(d) a two-dimensional spatial light modulator disposed in said object beam
to modulate said object beam with optical information as a function of
signals connected to X and Y inputs thereof;
(e) a first television camera for developing X and Y signals reflecting the
contents of its field of vision, said X and Y signals being connected to
said X and Y inputs of said two-dimensional spatial light modulator;
(f) a hololens positioned in said object beam subsequent to said
two-dimensional spatial light modulator to focus said object beam at a
plurality of focal points;
(g) a planar transparency-forming film disposed with said focal points on
an exposable surface thereof to form a multiple position interference
filter upon exposure of said exposable surface and subsequent development
processing of said film;
(h) means for directing said reference beam onto said exposable surface of
said film to expose said exposable surface in combination with images
focused by said hololens to form interference patterns on said exposable
surface; and,
(i) means for simultaneously sensing and indicating light passage through
respective ones of the positions of said multiple position interference
filter following development processing of said exposable surface whereby
simultaneous recognition of objects corresponding to respective ones of
said positions of said multiple position interference filter is affected.
7. The apparatus of claim 6 wherein:
said means for simultaneously sensing and indicating light passage through
respective ones of the positions of said multiple position interference
filter includes a second television camera containing a matrix of charge
coupled devices and means for focusing light passing through said
interference filter onto said matrix.
8. The apparatus of claim 7 wherein:
said means for simultaneously sensing and indicating light passage through
respective ones of the positions of said multiple position interference
filter employs outputs of the charge coupled devices to indicate light
passage at each position of the interference filter and includes means for
indicating light passage only if light passing through a position is above
a pre-established threshold level corresponding to object recognition.
9. The method of optically recognizing individual pre-defined ones of a
plurality of possible orientations of an object within a field of vision
without the necessity of including a step for sequentially comparing to a
series of pre-defined position definitions comprising the steps of:
(a) pre-defining the orientations of the object to be recognized by the
steps of,
(a1) providing a controlled source of a coherent collimated light beam and
means for splitting the light beam into an object beam and a reference
beam;
(a2) disposing a two-dimensional spatial light modulator in the path of the
object beam to modulate the object beam with optical information as a
function of signals connected to X and Y inputs thereof;
(a3) providing a television camera to develop X and Y signals reflecting
the contents of its field of vision;
(a4) connecting the X and Y signals to the X and Y inputs of the
two-dimensional spatial light modulator;
(a5) disposing a hololens in the path of the object beam subsequent to the
two-dimensional spatial light modulator to focus the object beam at a
plurality of focal points in a plane;
(a6) disposing unexposed transparency-forming film with an exposable
surface thereof in the plane of the focal points;
(a7) providing means for directing the reference beam onto the exposable
surface of the film to expose the exposable surface in combination with
images focused by the hololens forming interference patterns on the
exposable surface;
(a8) placing the object within the field of vision of the television camera
in a first orientation to be recognized;
(a9) covering the exposable surface of the film except for one focal point
location thereof;
(a10) turning on the coherent collimated light beam to expose the exposable
surface of the film at the one exposed focal point location;
(a11) repeating steps (a8) through (a10) with different orientations and
focal point locations to expose points of a multiple position interference
filter;
(a12) development processing the film to form the multiple position
interference filter; and thereafter,
(b) subsequently recognizing the orientation of the object by the steps of,
(b1) disposing the multiple position interference filter with the points
thereof in the plane of the focal points;
(b2) operatively positioning means for sensing and indicating light passage
through respective ones of the positions of the multiple position
interference filter;
(b3) directing the field of vision of the television camera on an area
containing the object;
(b4) turning on the coherent collimated light beam to create only the
object beam with the contents of the field of vision of the television
camera dynamically impressed on the object beam by the two-dimensional
spatial light modulator; and
(b5) simultaneously monitoring said sensing and indicating means for
indications of light passage through ones of the positions of the multiple
position interference filter whereby instant recognition of the
orientation of the object corresponding to respective ones of the
pre-defined positions of the multiple position interference filter is
affected.
10. The method of claim 9 wherein:
said step of simultaneously monitoring said sensing and indicating means
for indications of light passage through ones of the positions of the
multiple position interference filter includes the step of indicating
light passage only if light passing through a position is above a
pre-established threshold level corresponding to object orientation
recognition.
11. The method of claim 10 and additionally comprising the step for
tracking the object of:
focusing light passing through a position above said pre-established
threshold level onto a charge coupled device to create a two-dimensional
image of the field of view of the television camera and the object therein
whereby movement of the object can be seen and visually tracked.
12. Apparatus for optically simultaneously recognizing a plurality of
objects within a field of vision comprising:
(a) a laser producing a coherent laser beam;
(b) a beam splitter disposed to split said laser beam into an object beam
and a reference beam;
(c) beam expanders and collimators positioned to transform said object beam
and said reference beam into coherent collimated light beams;
(d) a two-dimensional spatial light modulator disposed in said object beam
to modulate said object beam with optical information as a function of
signals connected to X and Y inputs thereof;
(e) a first television camera for developing X and Y signals reflecting the
contents of its field of vision, said X and Y signals being connected to
said X and Y inputs of said two-dimensional spatial light modulator;
(f) a hololens positioned in said object beam subsequent to said
two-dimensional spatial light modulator to focus said object beam at a
plurality of focal points;
(g) a planar transparency-forming film disposed with said focal points on
an exposable surface thereof to form a multiple position interference
filter upon exposure of said exposable surface and subsequent development
processing of said film;
(h) means for directing said reference beam onto said exposable surface of
said film to expose said exposable surface in combination with images
focused by said hololens to form interference patterns on said exposable
surface; and,
(i) means for simultaneously sensing indicating light passage through
respective ones of the positions of said multiple position interference
filter following development processing of said exposable surface whereby
simultaneously recognition of objects corresponding to respective ones of
said positions of said multiple position interference filter is affected.
13. The apparatus of claim 12 wherein:
said means for simultaneously sensing and indicating light passage through
respective ones of the positions of said multiple position interference
filter includes a second television camera containing a matrix of charge
coupled devices and means for focusing light passing through said
interference filter onto said matrix.
14. The apparatus of claim 13 wherein:
said means for simultaneously sensing and indicating light passage through
respective ones of the positions of said multiple position interference
filter employs outputs of the charge coupled devices to indicate light
passage at each position of the interference filter and includes means for
indicating light passage only if light passing through a position is above
a pre-established threshold level corresponding to object recognition.
15. In Vander Lugt filter type apparatus for optically recognizing an
object within a field of vision including a source of a coherent light
beam; a beam splitter disposed to split the light beam into an object beam
and a reference beam; beam expanders and collimators positioned to
transform the object beam and the reference beam into coherent collimated
light beams; a transparency-forming film disposed form an interference
filter upon exposure of said exposable surface and subsequent development
processing of the film; means for directing the reference beam onto the
exposable surface of the film to expose the exposable surface in
combination with an image focused to form an interference pattern on the
exposable surface; and, means for sensing and indicating light passage
through the interference pattern position of the interference filter
following development processing of the exposable surface whereby
recognition of an object corresponding to the one used to create the
interference filter is affected, the improvement to allow simultaneous
recognition of multiple objects within the field of vision comprising:
(a) two-dimensional spatial light modulator disposed in the object beam to
modulate the object beam with optical information as a function of signals
connected to X and Y inputs thereof;
(b) a first television camera for developing X and Y signals reflecting the
contents of its field of vision, said X and Y signals being connected to
said X and Y inputs of said two-dimensional spatial light modulator;
(c) a hololens positioned in the object beam subsequent to said
two-dimensional spatial light modulator to focus the object beam at a
plurality of focal points;
(d) means for positioning the transparency-forming film with said focal
points on an exposable surface thereof to form a multiple position
interference filter upon exposure of said exposable surface and subsequent
development processing of said film;
(e) the means for directing said reference beam onto said exposable surface
of said film including means to expose said exposable surface in
combination with multiple images focused by said hololens to form a
plurality of interference patterns on said exposable surface; and,
(f) the means for sensing and indicating light passage including means for
simultaneously sensing and indicating light passage through respective
ones of the positions of said multiple position interference filter
following development processing of said exposable surface whereby
simultaneous recognition of objects corresponding to respective ones of
said positions of said multiple position interference filter is affected.
16. The improvement of claim 15 wherein:
said means for simultaneously sensing and indicating light passage through
respective ones of the positions of said multiple position interference
filter includes a second television camera containing a matrix of charge
coupled devices and means for focusing light passing through said
interference filter onto said matrix whereby light passage through
individual positions of said interference filter can be determined by the
presence of light at corresponding positions of said matrix.
17. The apparatus of claim 16 wherein:
said means for simultaneously sensing indicating light passage through
respective ones of the positions of said multiple position interference
filter employs outputs of the charge coupled devices to indicate light
passage at each position of the interference filter and includes means for
indicating light passage only if light passing through a position is above
a pre-established threshold level corresponding to object recognition.
18. The improvement of claim 15 wherein:
said means for simultaneously sensing and indicating light passage through
respective ones of the positions of said multiple position interference
filter includes a second television camera containing a matrix of charge
coupled devices and means for focusing light passing through at least one
position of said interference filter onto said matrix to create a
two-dimensional image of the field of view of the first television camera
and the objects therein for use in visually tracking movement of the
objects. |
|
|
|
|
Claims  |
|
|
Description  |
|
|
TECHNICAL FIELD
The present invention relates to tracking systems and, more particularly,
to an optical tracking system for recognizing and tracking multiple
objects in real time.
DESCRIPTION OF THE PRIOR ART
Object detection and tracking as accomplished in military command and
control systems and air traffic control systems is a straightforward
problem that has been accomplished with the combination of radar (for
detecting) and digital computers (for tracking). All that is required in
such applications is the detection of one or more objects within an area
of two-dimensional or three-dimensional space from the radar source.
The combination of object recognition and tracking, however, is another
matter. A prior art system for accomplishing such as combination of
functions is shown in simplified block diagram form in FIG. 1. Assuming
that a triangular shaped object 10 and a circular shaped object 12 are
moving within a two-dimensional area 14 they can be recognized and tracked
within the area 14 by the components shown in FIG. 1 according to prior
art techniques. The area 14 is divided into an M.times.N matrix of
discreetly addressable locations or pixels and viewed by a television
camera 16. The information from the television camera 16 relative to the
pixel positions within the area 14 is output to a computer 18 on a
periodic basis. The period of the output, of course, is established as a
function of the speed of movement of the objects 10, 12. For slow-moving
objects, the period or sampling rate is long while, on the other hand, for
fast-moving objects the sampling rate or period between data output must
be short. The computer 18 stores the data from the camera 16 in a memory
matrix 20 containing a historical file of the data for the present time
(n), the previous time (n-1), etc. The size or number of the historical
snapshots is dependent upon the amount of information relative to the
object movement that is desired. If only instantaneous relative movement
since the last data is required, only a single history of time n-1 is
required. If a more detailed tracking profile is required, obviously more
data must be retained. In any event, those skilled in the art will
appreciate that in order to "recognize" objects 10, 12 employing the
digital computer approach of FIG. 1 a detailed programming task must be
undertaken relative to the data in each instance. First, the edges of the
objects 10, 12, must be located and defined. Having thus established the
edge locations, they must then be analyzed to determine whether they are
objects to be recognized, i.e. a triangle or a circle. Such a digital
approach to object recognition and tracking is computationally intensive,
requiring large quantities of time, space, and money to accomplish it.
Obviously, objects more complex in shape than a simple triangle or circle
intensify the problem.
On the other side of the coin, object recognition using optical techniques
is known in the art. As shown in FIG. 2A, a collimated beam of light 22
impressed with a known pattern (e.g. the letter "A") can be split by a
beam splitter 24 into an object beam 26 and a reference beam 28. If the
object beam 26 is then focused by lens 30 onto a transparent film 32 and,
simultaneously, the reference beam 28 is used to illuminate the film 32
after traveling a substantially identical path length to that of the
object beam 26, the film 32 will be exposed with an interference pattern
of the letter A. If, subsequently, a light beam 22' as shown in FIG. 2B is
focused onto the developed film 32' (acting as a spatial filter) and the
output, if any, is refocused by a second lens 34, a spot 36 will appear
if, and only if, there is correlation between the image impressed on the
light beam 22' (in this example another letter A) and the previously
established interference pattern on the film 32'. This is known as a
Vander Lugt filter, which is well known in the art. With the advent of
dynamically modifiable spatial light filter elements such as liquid
crystal and magneto-optic filters, the film 32 has been replaced by such
devices in tested systems so that object recognition can take place in
real-time by driving the dynamic spatial filter with a series of
pre-established interference patterns. Unfortunately, there is nothing in
the prior art which provides the capability of employing such optical
object recognition techniques with the ability to track the objects once
recognized.
DISCLOSURE OF THE INVENTION
The present invention has provided an optical recognition and tracking
capability by the apparatus for recognizing a plurality of objects within
a field of vision comprising, a laser producing a coherent laser beam; a
beam splitter disposed to split the laser beam into an object beam and a
reference beam; a pair of beam expanders and collimators positioned to
transform the object and reference beams into coherent collimated light
beams; a two-dimensional spatial light modulator disposed in the object
beam to modulate the object beam with optical information as a function of
signals connected to X and Y inputs thereof; a television camera for
developing X and Y signals reflecting the contents of its field of vision,
the X and Y signals being connected to the X and Y inputs of the
two-dimensional spatial light modulator; a hololens positioned in the
object beam subsequent to the two-dimensional spatial light modulator to
focus the object beam at a plurality of focal points; a planar
transparency-forming film disposed with the focal points on an exposable
surface thereof to form a multiple position interference filter upon
exposure of the exposable surface and subsequent development processing of
the film; means for directing the reference beam onto the exposable
surface of the film to expose the exposable surface in combination with
images focused by the hololens to form interference patterns on the
exposable surface; and, means for sensing and indicating light passage
through respective ones of the positions of the multiple position
interference filter following development processing of the exposable
surface whereby recognition of objects corresponding to respective ones of
the positions of the multiple position interference filter is affected.
In the preferred embodiment, the means for sensing and indicating light
passage through respective ones of the positions of the multiple position
interference filter includes a second television camera containing a
matrix of charge coupled devices and means for focusing light passing
through the interference filter onto the matrix.
Additionally in the preferred embodiment, the means for sensing and
indicating light passage through respective ones of the positions of the
multiple position interference filter employs outputs of the charge
coupled devices to indicate light passage at each position of the
interference filter and includes means for indicating light passage only
if light passing through a position is above a pre-established threshold
level corresponding to object recognition.
For tracking of one or more objects, light passing through positions above
the pre-established threshold level is focused onto a second television
camera to create a two-dimensional image of the field of view of the first
television camera and the objects to be tracked therein.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified drawing showing a prior art approach to using a
digital computer and television camera to recognize and track objects.
FIG. 2A is a simplified drawing showing the prior art technique of creating
a Vander Lugt filter to be used in object recognition.
FIG. 2B shows the way that the Vander Lugt filter of FIG. 2A is employed to
recognize an object optically.
FIG. 3 is a simplified drawing showing the manner in which a multiple focus
hololens produces multiple focal points of the same image.
FIG. 4 is a simplified perspective drawing showing the apparatus employed
in the present invention during filter preparation | | |