null  null
US006254239B1
(12) United States Patent
(10) Patent N0.:
(45) Date of Patent:
Hibner, 11 et al.
(54)
METHOD AND SYSTEM FOR IMAGE
VISUALIZATION
US 6,254,239 B1
Jul. 3, 2001
“SYNELEC Lite Master” information/presentation from
(75) Inventors: Rodney C. Hibner, II, Collin; Mervin
L Gangstead, Dallas, both of TX (US)
DLP, A Texas Instruments Technology; including informa
tion on the Lite Master DLP Projection Cubes, Unique
BlackScreen Technology, and Synelec’s Lite Master Projec
tion Cubes entitled The First ‘Plug & Play’ DLP Video Walls
(73) Assignee: Raytheon Company, Lexington, MA
in the World; 4 pages.
“Panoram” information/ presentation from Panoram Tech
(Us)
(*)
Notice:
nologies, Inc.; Website: WWW.panoramtech.com; @ 1999; 2
Subject to any disclaimer, the term of this
patent is extended or adjusted under 35
U.S.C. 154(b) by 0 days.
“Netmaster Systems EQ4052—S DLP Display Wall Cube”
information/presentation from Electrohome Visionary
Thinking; Web—Site WWW.electrohome.com; 2 pages.
“Mirage Vision MV—50DG” article, Gundermann VideoW
all, Web—Site: WWW.videoWall.de; 2 pages.
“The Maximum System, The High—De?nition System for
(21) Appl. No.: 09/364,851
(22) Filed:
pages.
Jul. 30, 1999
Maximum Display” pamphelt, featuring the ict—SPLITMA
CHINE and ict—CONTROLMACHINE, by Video Visions;
(51)
Int. Cl.7 ................................................... .. G03B 21/26
Web—Site WWW.Video—Visions.com; 4 pages (actually tWo—
(52)
(58)
US. Cl. .............................. .. 353/94; 353/121; 353/69
Field of Search .............................. .. 353/94, 30, 121,
folded in half).
(List continued on next page.)
353/69, 70; 352/69, 70, 133; 348/750, 751,
840
Primary Examiner—William DoWling
(74) Attorney, Agent, or Firm—Baker Botts L.L.P.
(56)
References Cited
(57)
U.S. PATENT DOCUMENTS
3,602,582 *
8/1971
4,392,187 *
7/1983 Bornhorst
An apparatus for visualizing image data comprises a ?rst
Torricelli .............................. .. 352/41
5,902,030
*
5/1999
Blanchard
.........
projector (28) and a second projector (29). The ?rst projector
362/233
(28) is positioned With a ?rst optical axis perpendicular to an
362/85
image focal plane (40), and projects to the focal plane (40)
4,980,806 * 12/1990 Taylor et a1. ..
5,988,817 * 11/1999
ABSTRACT
. . . . ..
353/94
MiZushima et al. ................. .. 353/94
OTHER PUBLICATIONS
“Introducing ComVieW Graphics” article from ComVieW
Graphics—Large scale display systems; Web—Page: http://
WWW.cvgl.com/corporate/about.html; introduced at Infocom
Jun. 10—12, 1999; 2 pages.
“The VieWBoard—Highest quality solution for data visual
ization” article from ComVieW Graphics; 1 page.
“The VieWBoard—Speci?cations” article from ComVieW
Graphics; 1 page.
a ?rst image (A) With a ?rst image area. The second
projector (29) is positioned in relative alignment With the
?rst projector (28), With a second optical axis perpendicular
to the focal plane (40). The second projector (29) projects to
the focal plane (40) a second image (B) With a second image
area adjacent to the ?rst image area. A method for visual
iZing image data comprises projecting to an image focal
plane (40) a ?rst image (A) With a ?rst image area, and a
second image (B) With a second image area. The ?rst image
area is adjusted to be juxtaposed to the second image area.
14 Claims, 5 Drawing Sheets
STRAIGHTEN SCREEN
ADJUST PARALLELISM
0F SCREEN IO RACKS
ADJUST RAlLS T0 LEVEL
3
82
ALL
RAILS DONE
?
84
YES
MOUNT AND SQUARE
PROJEUORS AND
TRANSLATORS TO RAIL
MEASURE TOPVEOTTOM
OR LEFT-RIGHT
DIFFERENCE
85
RECENTER WAGE
ALL
PROJECTORS
DONE
WITHIN
'!
IOLEEANCE
S
93
'
VES
US 6,254,239 B1
Page 2
OTHER PUBLICATIONS
“OverVieW—MP, Modular Design of a Display Wall Based
on Poly—Silicon LCD Rear Projection Technology”, Barco,
Web—Sites at WWW.seufert.corn and WWW.barco.corn; Mar.
1999; 2 pages.
“Large Venue Vision and Performance, Seleco SDV 52
DataWall Projection Systern” pamphlet/presentation, Seleco
The Americas, Web—site: WWW.oWl—video.corn; Apr. 1999;
2 pages.
* cited by eXarniner
U.S. Patent
Jul. 3, 2001
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US 6,254,239 B1
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sheet 3 0f 5
US 6,254,239 B1
FIG. 3
STRAIGHTEN SCREEN
,so
i
ADJUST PARALLELISM
/' 81
OF SCREEN TO RACKS
I
ADJUST RAILS TO LEVEL
V
MOUNT AND SQUARE
PROJECTORS AND
TRANSLATORS TO RAIL
MEASURE TOP-BOTTOM
0R LEFT-RIGHT
DIFFERENCE
94
/
ADJUST AND
R IMAGE
II
FOCUS AND POSITION LENS
USING ALIGNMENT PATTERN
I
ESTABLISH POSITION
FOR REFERENCE IMAGE
SET MAGNIFICATION AND CENTER
I
[100
REGISTER REFERENCE To FIRST
(VERTICAL AND HORIZONTAL) \101
NEIGHBORS
IT
REGISTER NEXT IMAGE
TO VERTICAL AND
HORIZONTAL NEIGHBORS
U.S. Patent
Jul. 3, 2001
Sheet 4 0f 5
FIG. 4
FIG. 5
US 6,254,239 B1
U.S. Patent
Jul. 3, 2001
Sheet 5 0f 5
US 6,254,239 B1
US 6,254,239 B1
1
2
METHOD AND SYSTEM FOR IMAGE
VISUALIZATION
an image focal plane a ?rst image With a ?rst image area,
projecting to the focal plane a second image With a second
image area, and aligning the ?rst image area to be juxta
posed to the second image area.
One technical advantage of the present invention is in
TECHNICAL FIELD OF THE INVENTION
This invention relates in general to the ?eld of image
projection and processing and more particularly, the inven
applications Where users require or desire multiple image
displays, Where contextual information is available to
tion relates to a method and system for image visualiZation.
adequately infer, deduce, or analyZe. Another technical
BACKGROUND OF THE INVENTION
In conventional image projection systems, there is gen
erally a single projector projecting a single image. Such an
image may be projected forward or backward, according to
the type of projector used.
It is knoWn to use the concept of a “video Wall” to project
multiple images, or to project portions of a single image
advantage of the invention is that image overlaps are not
10
computers, video displays and image processing algorithms.
BRIEF DESCRIPTION OF THE DRAWINGS
15
For a better understanding of the present invention, ref
erence may be made to the accompanying draWings,
Wherein:
arranged to simulate the look and feel of a larger image. For
example, nine televisions (video displays) are disposed
Within a single Wall in a three-by-three matrix. Each tele
vision displays the same image, or displays one-ninth of a
FIG. 1 is a system level diagram of an embodiment of an
image visualiZation system according to the teachings of the
scene. The effect of the latter is that the scene appears to be
present invention;
the dimension of the nine television displays, although
interrupted by the spacing betWeen each television. Other
approaches project multiple images on a Wall, and by
overlapping and performing image processing on the images
such as averaging, to give the appearance of continuity.
Other multiple image displays simply leave gaps of about a
FIG. 2 is a diagram of one embodiment for image
placement in a focal plane;
FIG. 3 is a How chart describing an alignment procedure
25
for an image visualiZation system as shoWn in FIG. 1;
FIG. 4 is a diagram illustrating typical optical distortion
corrected by proper image placement in a focal plane;
quarter inch betWeen the neighboring images.
Multiple image displays may be required in cases typi
cally encountered in image processing, Where datasets are
FIG. 5 is a schematic diagram of an alignment control
according the present invention;
too large to display using one video display. For example, a
physician or analyst may need to vieW a large dataset that
exceeds hardWare framing limitations. When examining
such a large dataset across multiple image displays, the
physician or analyst typically encounters problems in exam
ining the importance of the data in the mullions betWeen
altered betWeen neighboring images. Another technical
advantage of the invention is the use of standard projectors,
FIG. 6 is an alignment pattern for an image visualiZation
system as shoWn in FIG. 1; and
FIG. 7 is a schematic diagram of another embodiment of
an image visualiZation system according to the present
35
neighboring images. In this scenario, the analyst requires
invention.
DETAILED DESCRIPTION OF THE
INVENTION
additional contextual cues in displaying multiple images to
adequately infer, deduce or conclude, including the ability to
Referring to FIG. 1, there is shoWn a system diagram of
vieW such data seamlessly from one image to the next.
In systems such as information visualiZation and
an embodiment of an image visualiZation system 10 accord
management, Where seamlessness betWeen multiple images
provides signi?cant advantages, a problem arises When the
ing to the present invention. A plurality of projectors 28 to
39 supported by racks 50 projects a plurality of images A—L
need to access information in adjacent images is disrupted
by a mullion in the information such as averaged or missing
data betWeen the images. These circumstances exist When
there is an image overlap, or even a black gap. Thus, When
a user of the image displaying data needs to move betWeen
45
TWelve generally non-scanning projectors each project an
image of 1280x1024 pixels. Each image is focused to a focal
plane generally corresponding to a location of screen 40
these images, his/her ability to integrate, infer, deduce, and
conclude is disrupted by such interruptions betWeen images.
having dimensions length 42 by height 41 suitable to display
images A—L projected by projectors 28—39. An image pro
jected by each projector generally has dimensions of length
SUMMARY OF THE INVENTION
45 by height 44 on screen 40. Each image projected by
Therefore, a need has arisen for a method and system for
image visualiZation that overcomes the disadvantages and
de?ciencies of the prior art.
In accordance With the present invention, an apparatus for
visualiZing image data comprises a ?rst projector and a
second projector. The ?rst projector is positioned With a ?rst
55
and projects to the focal plane a ?rst image With a ?rst image
area. The second projector is positioned in relative align
ment With the ?rst projector, With a second optical axis
generally perpendicular to the focal plane. The second
projector projects to the focal plane a second image With a
method for visualiZing image data comprises: projecting to
projectors 28—39 is adjacent to the next image so that the
images A—L are substantially seamless as displayed on
screen 40. The placement and details for such images Will be
discussed in further detail in conjunction With FIG. 2.
Non-scanning projectors 28—39 are particularly advanta
geous for their ability to generate images in physically stable
positions. This type of projector typically includes a lens
With a ?at ?eld, loW distortion and good symmetry. Such
lenses are mechanically stable and precisely adjustable, and
optical axis generally perpendicular to an image focal plane,
second image area adjacent to the ?rst image area.
Further in accordance With the present invention, the
(see FIG. 2) to screen 40. The projectors 28—39 are coupled
to computer 20.
yield reproducible results. Atypical projector includes micro
mirror or liquid crystal display (LCD) projectors. One such
65
projector is Texas Instrument’s Digital Micro Mirror
DeviceTM (DMD). Other suitable projectors, such as opti
cally scanning projectors, may also be suitable to use in
system 10.
US 6,254,239 B1
4
3
Projectors 28—39 typically display any information input
properties may also be provided by, for example, precisely
to each projector, such as text, graphics and video. The video
con?gured individual baf?es or Fresnel lenses for each
may be analog or digital. For example, the DMD provides
8—10 bits per color of gray scale, Which gives 256 different
shades of each of the primary colors thereby alloWing for
projector.
A display con?guration generally includes balancing the
gain of screen 40 With the projection distance 55, and proper
alignment and tooling to minimiZe artifacts for the bound
roughly 16.7 million different color combinations to be
created digitally.
aries of such lenses. A screen 40 as described is also
particularly advantageous for the property to remain gener
ally ?at, or perpendicular relative to the optical axis of each
Projectors 28—39 are con?gured to form an array of 2x6
images A—L. Any suitable con?guration of M><N may be
used, Where M denotes the number of roWs and N denotes
10
the number of columns of images. For example, it may be
projector 28—39.
Computer 20 is a suitable platform that performs any
image or data processing typically used in system 10.
advantageous to have a linear array of 1><N images, or a
square array of M><N images, Where M=N.
Computer 20 provides input video, image, or graphics data
Each image projected by projectors 28—39 comprises a
plurality of pixels. For example, each 1280x1024 pixel
for projectors 28—39. In one embodiment of the invention,
15
image A—L comprises 1024 lines and 1280 roWs of pixels.
Images A—L are generally rectangular, each With a de?ned
image area. Any suitable image siZe may be used. To
increase resolution, more pixels per inch may be used. Such
a con?guration is provided by resealing, for example, by
including more projectors and changing the image magni
be any other suitable platform With softWare and data
storage to provide image processing applications dictated by
the needs of system 10 users.
20
?cation of each projector, or by including more mirrors in
each DMD projector.
To increase the precision of positioning projectors 28—39
relative to screen 40, the plurality of projectors 28—39 is
supported by a plurality, i.e. three, racks 50 and rails 52.
Each projector 28—39 is supported by a pair of rails 52 to
enable the projector to slide toWards and aWay from screen
40. Racks 50 and rails 52 are each made from a generally
rigid material, for example, aluminum. Such a material is
advantageous to use for its stability, strength, and vibration
dampening properties. Other suitable materials may also be
25
30
users may Wish to display and register large maps or
graphics to large data sets that span the capacity of several
projectors for inference and deduction.
Color, black and White, analog or digital images may be
projected by the system 10. System 10 may also display
35
40
stereo data. Such data may be vieWed, for example, in
anaglyph form With any suitable red-green glasses.
Typically, projection of such images includes at least 8 bits
of resolution per pixel. For a color image, each pixel requires
8 bits per color, or 24 bits of resolution per pixel. Pixel depth
is limited only by projector optics. Thus, projection and
processing of a large array of images A—L generate large
amounts of image data to be processed for decision making
capabilities that include integrating the data With other
referenced data, e.g., maps, reference points, graphics, and
end to end of roughly 54 inches as projected on screen 40.
At distance 55 of about ten feet, pixel siZes on the screen 40
are generally 0.030 inch, corresponding to generally to 30
pixels per inch. This distance is particularly advantageous
for vieWing images A—L at, for example, arm’s length. The
displays for a large vieWing audience. Also, the system 10
may be used for decision-making applications, typically
including general electronic light table functions, sequenc
ing of images, and registration of images to reference data,
etc. Typical decision-making includes inference and
deduction, requiring resolution and accuracy that only near
Screen 40 is generally located in an x-y plane at distance
55 (in the Z direction) of about ten feet from the screen of
projectors 28—39. At a distance 55 of about ten feet, the
plurality of images A—L comprise an array measuring from
In operation, system 10 has utility for a variety of needs.
For example, system 10 may be used to project or tile
seamless, multi-image presentation provides. For example,
used. It is also Within the scope of the invention to use other
suitable con?gurations for supporting and positioning pro
jectors 28—39.
the computer 20 is a Silicon Graphics Incorporated (SGI)
ONYX II With four video graphic pipes. Computer 20 may
45
the like.
projection distance 55 may be varied according to user
needs, and generally varies With a user’s distance from
Alignment and operation of projectors 28—39 and screen
40 properly places images A—L in focus for users of the
screen 40. For example, for larger images (and thus larger
pixel siZes), the projection distance 55 could be increased. In
system 10. Many computer platforms 20 typically provide
the functionality for decision-making applications dictated
this respect, a user’s eyes can integrate over ?lm ?icker 50 by the needs of users. For example, video cards regularly tile
video displays so that a mouse may move from one image
speeds appropriately-siZed pixels and luminance into con
tinuous image data.
In addition to the geometrical relationship betWeen pro
jectors 28—39, screen 40 and a user, screen 40 is selected
from a material such as DaLite Dual Vision to provide the 55
contiguous virtual “?y-through” of images A—L. Separate
loWest, yet most uniform gain achievable across length 42.
The gain and uniformity are inversely related and thus are
traded-off With the needs of system 10. Screen 40 having
video processing may be used to enhance processing speeds
as desired.
these gain and uniformity properties is advantageous in
alleviating the discontinuities in illumination across the ?eld
Referring noW to FIG. 2, there is shoWn a diagram of one
60
of images A—L caused by stray light illuminated outside a
projection area. Typically, the luminance of each pixel varies
With the user’s position With respect to scattered and direct
incident light from each individual projectors 28—39. Screen
40 With these gain and uniformity properties uniformly
distributes the gain and luminance of images A—L to a user
vieWing any portion of images A—L on screen 40. Similar
to another. SGI’s Onyx II provides very fast processing and
frame refreshing, and Will automatically stack and tile
images A—L in a desired orientation. For electronic light
table functions, a computer such as the Onyx II provides
embodiment for image placement in a focal plane according
to the teachings of the present invention. Images A—L are
shoWn as projected in the focal plane co-located in screen
40. Each image A—L has dimensions length 45 and height 44
and is generally centered at the optical axis of each projector
65
28—39. Each image is to be located such that one edge is
juxtaposed to an edge of its nearest neighbor. Such adja
cency is near seamless. For example, the top roW of image
US 6,254,239 B1
5
6
B begins Where the next roW of pixels after the last roW of
In step 81, the parallelism of racks 50 to screen 40 is
adjusted. Mean distance is used for all four edges of screen
40 to establish distance, tilt, and parallelism of the racks 50
pixels displayed at the bottom of image A should lie.
Similarly, the right edge of image C begins Where the next
column of pixels after the last column of pixels displayed at
to screen 40. In step 82, the rails 52 for a projector are
the left edge of image A should lie, and so on. It is
leveled using a surveyors telescopic sight. HoriZontal and
particularly advantageous for such placement to be accurate
vertical distances to a screen center section are measured
Within a fraction of a pixel, e.g., one-quarter pixel or, in
and averaged. The position and tilt of rails 52 are then
adjusted in step 82 until level Within acceptable limits. Such
some cases, to Within an acceptable tolerance over Which
human eyes may integrate.
Screen 40 may be supported in a generally ?at position by
a rigid frame (not explicitly shoWn) Any suitable means for
retaining a generally ?at shape relative to the optical axes of
limits are predetermined to achieve a desired accuracy at a
10
rails 52 and a translator 70 as shoWn in FIG. 5. Step 85
projectors 28—39 for screen 40 may be used. The screen
shape should be retained Within the accuracy of seamless
ness desired, e.g. one-quarter pixel.
A series of alignment lines 49 are stretched in front of
screen 40 as shoWn in order to align image placement in
screen 40. Thus, alignment lines 49 establish each center line
for images A—L. As can be seen from FIG. 2, centering lines
48 are suspended over the nominal centerlines of the pro
15
as described insures that the basic image block 200 is
20
25
In step 86, the lens of a projector is translated using its
translator 70 in the x and y directions (see FIG. 5) to align
the centerline of a projected image With the respective
centering lines 48 and 49. Details of translator 70 are
discussed in conjunction With FIG. 5.
30
present invention. Alignment generally comprises tWo
phases, and may be accomplished With or Without the use of
35
tem 10. The ?rst or coarse alignment phase establishes
locations for each of the projectors relative to screen 40. The
second or ?ne alignment phase adjusts pixel locations in
each image so that the plurality of images A—L are adjacent
to one another. Both phases of alignment are performed for
across all lines and columns of images A—L to establish
and alignment patterns are knoWn to those skilled in the art.
for an image visualiZation system using the teachings of the
a computer. Alignment may also comprise predetermined
measurements, or dynamic adjustments as required by sys
replicated throughout the corresponding image; that is,
adjacency of images A—L. Many mechanisms for alignment
screen 40 to be generally curved either convex or concave
relative to the plurality of projectors 28—39 as shoWn in FIG.
1.
FIG. 3 is a ?oWchart describing an alignment procedure
returns the process to step 84 for each of the projectors
28—39.
In step 86, a projector is focused to establish an alignment
pattern shoWn and discussed in FIG. 6. An alignment pattern
jected images. Such alignment lines and centering lines are
useful in establishing the relative alignment of projectors
28—39, and may be removed after projector alignment is
performed, as discussed in conjunction With FIG. 3.
Although screen 40 is shoWn in a generally straight
con?guration, it is also Within the scope of the invention for
speci?c distance 55. Step 83 then returns the process to
repeat step 82 for the rails 52 for each projector 28—39.
In step 84, a projector is centered on its corresponding
40
In step 88, magni?cation of a projector is set by ?rst
measuring dimensions of the projected image. Such mea
surement may be taken betWeen the center of the leftmost
pixel at the mid-height of the projected image on screen 40
to the center of the right-most pixel. A projector is then
moved, refocused and recentered until the measured Width
of the respective image area is appropriate. Such measured
Width is predetermined and is for example 41.97 inches, to
achieve 0.030“ pixel dimensions for each image. Ameasured
Width is selected to generally accommodate for lens
imperfections, as is discussed in conjunction With FIG. 4.
Next, a projector is centered relative to the respective
projected image on screen 40 by using an alignment tele
initially installing system 10, and the latter phase may be
scope (not shoWn) mounted to the rails 52. By using the
performed to correct any drift of the components.
The method used for alignment illustrated in FIG. 3
surements are taken betWeen the crosshairs on the telescope
alignment pattern as shoWn and discussed in FIG. 6, mea
28—39 relative to screen 40, establishing image positions for
and the pattern centerline. Steps 86, 88 and 90 are repeated
for each projector 28—39 to adjust images A—L projected to
each projector, image magni?cation, image centering, and
screen 40.
correction of keystoning effects. Steps 100—103 describe the
method for ?ne alignment, Which includes registering adja
In steps 92—94, vertical and horiZontal keystone distortion
for projectors 28—39 is determined and corrected. Keyston
comprises generally steps for positioning of projectors
cent images to one another so that each pixel on each image
45
50
edge is nearly adjacent to the next pixel on the next image
edge. Such a method aligns the plurality of projectors 28—39
in relative alignment With respect to screen 40, to adjust for
individual optical and mechanical imperfections of each
projector.
55
Coarse alignment begins at step 80, and includes straight
ening screen 40 to present a nearly ?at display. Screen 40
may be mounted in brackets, and alignment lines 49 are
stretched across the area of the screen 40 as discussed and
shoWn in FIG. 2. TWo centering lines 48, as illustrated in
FIG. 2, are hung in front of screen 40. In order to maintain
60
adjacency of images A—L, it is advantageous for screen 40
to be generally perpendicular to the optical axis of each
projector 28—39. Thus, screen 40 is ?at, Within the same
accuracy desired by users of system 10. For image adjacency
accuracy of one quarter pixel, such accuracy equals approxi
mately 1A1><0.030 inches.
ing may occur in either the vertical or y direction, the
horiZontal or x direction, or both. Such distortion results in
65
blooming, or enlarged areas, Where the optical axis of a
projector is not aligned perpendicular to the screen 40 and
the image area is not centered about the center point of the
image as displayed on screen 40. In step 92, the difference
in length 45 of each image is determined for vertical
keystone at the top and bottom edges of an image area, from
the center of the left pixel to the center of the right pixel.
Similarly, to determine horiZontal keystone, the difference in
height 41 of the image area at both the left and right edges
of the image is measured from the center of the top pixel to
the center of the bottom pixel. Should the difference be
Within an acceptable tolerance, e.g., a predetermined thresh
old such as one-third pixel, at step 93, no further adjustment
of the measured dimension is required.
Should adjustment be required, the image area is adjusted
and recentered in step 94 by rotation of the projector. For
US 6,254,239 B1
7
8
horizontal keystone, a projector is rotated about its vertical
axis, and for vertical keystone, a projector is rotated about its
present invention. Each projector is aligned using translator
lateral axis. Rotating each projector may be accomplished,
for example, by adjusting rails 52 for each projector. After
recentering the image in step 94, steps 92—94 are repeated
may be any standard translator that improves alignment for
each lens Within a projector. One such standard translator,
NeWport Corporation’s 462-XYZ, is a three-axis microme
ter positioning and alignment device for focus (Z) and lateral
70. Translator 70 moves in three dimensions, x, y, and Z, and
until the difference values are Within tolerance.
Fine alignment begins at step 100 Where a nearly exact
x-y position is established for a reference image area, by
centering the alignment pattern 200 on reference lines 48
and 49. Typically, the reference image area is centrally
located; for example, the reference is image E, see FIG. 2.
In step 101, the nearest vertical and horiZontal image neigh
bors F, C, and G are registered to image E. Thus, image F is
and vertical (e.g., x-y) adjustment. Typically, alignment of
each image A—L at distance 55 from screen 40 requires that
each lens for projectors 28—39 be aligned Within an accept
10
registered to image E by ?rst displaying the alignment
pattern illustrated in FIG. 6 for projectors 32 and 33 corre
sponding to images E and F. Image F is moved laterally or
able tolerance. For example, alignment of images A—L to
Within a quarter pixel accuracy at distance 55 optically and
geometrically requires that each lens be focused Within a 10
micrometer accuracy.
FIG. 6 is an alignment pattern for an image visualiZation
15
system using the teachings of the present invention. FIG. 6
in the x direction to establish a position of or register its
comprises a matrix of image blocks 200 that are siZed to
cover an entire image of dimension length 45 and height 44.
image With image E. Image F is then moved in the vertical
Length 45 comprises 1280 pixels and height 44 comprises
or y direction to bring the top middle pixel Within a
1024 pixels. Thus, each image block 200 comprises a
symmetric 128 pixel square.
Image block 200 is particularly advantageous for per
tolerance, such as one-quarter pixel, of the corresponding
pixel on image E. Images C and G are similarly aligned to
image E at the right and left middle pixels, respectively.
In step 102, the remaining image neighbors are registered
to a nearest vertical and horiZontal image neighbor. Thus,
image D is registered to both image C and to image F. Step
25
forming alignment measurements in order to achieve rela
tive alignment of each projector With respect to screen 40, as
Was described in conjunction With FIG. 3. Such relative
alignment accounts for imperfections in each projector, to
103 then returns the process to repeat step 102 for each of
maintain geometric and optical placement of each pixel for
the remaining images A, B, and H—L until images A—L are
each registered adjacent to the image neighbors. Such reg
each image. The center 220 of image block 200 comprises
istration as performed in steps 100—103 must also accom
modate any lens imperfections, such as those discussed in
comprises an inner and outer border 235, 225 that are 124
four pixels as shoWn in FIG. 6. Image block 200 also
and 128 pixels, respectively, in length as shoWn in FIG. 6.
further detail in conjunction With FIG. 4.
FIG. 4 is a diagram illustrating typical optical distortion
corrected by proper image placement in a focal plane
according to the teachings of the present invention. To
achieve near seamless projection in system 10, any residual
“barrel” distortion shoWn in FIG. 4 caused by imprecise
manufacturing in a projection lens is to be removed, or
It is also Within the scope of the invention for screen 40
to have a generally curved shape. To seamlessly align
images A—L on a curved screen 40, it is necessary to align
35
accommodated. True seamless adjacency requires images A,
B, C, and D to be seamlessly adjacent along substantially the
entirety of the image areas of neighboring images, not
enables subsequent optical and geometrical alignment of
images A—L as discussed above.
FIG. 7 is a schematic diagram of another embodiment of
an image visualiZation system constructed according to the
merely near the center of each length 45 and height 44.
Seamless projection also involves matching the scale of
teachings of the present invention. System 10 comprises
adjacent projectors, so that corresponding pixels in the ?rst
and last roWs of each adjacent image are also aligned.
Typically, such alignment includes removing optical effects
and maintain the optical axis for each projector to both the
center for its corresponding image, as Well as perpendicular
to an image center on screen 40. Such optical and geometric
placement for projectors 28—39 With respect to screen 40
45
of each of the projectors, such as residual barrel distortion
and keystoning. A method for such alignment Was discussed
in detail in conjunction With FIG. 3.
four projectors 130—133, tWo mirrors 120 and 121 for each
projector, and screen 40.
This embodiment of system 10 uses suitable folded optics
to project images A—D to screen 40. For each projector, tWo
mirrors 120 and 121 are used to shorten the distance from
each projector to screen 40. Algorithms for applying folded
During adjustment of each relatively aligned projector,
optics solutions to typical geometric con?gurations are
barrel distortion due to lens imperfections causes typical
separations as shoWn in FIG. 4 in height 44 of delta y equal
knoWn to those skilled in the art, and any suitable folded
to about one pixel. Similarly, separation betWeen laterally
adjacent images A and C, or delta x, is typically 1—2 pixels.
jectors 130—133 are located in FIG. 7 above and beloW
optics con?guration may be used. Thus, for example, pro
Such separation or gaps are to be accommodated in the 55 screen 40, respectively, but may be located in other positions
(e.g.,A & B, andA & C) at their midpoints (denoted by x’s).
relative to screen 40 using other suitable folded optics
con?gurations. Such a con?guration reduces the volume
needed for system 10 as Well as easing performance of
Overlapping should be maintained so that each corner of
maintenance. It is particularly advantageous to use such a
alignment procedure. For example, one such approach for
accommodating such gaps is to overlap neighboring images
each image becomes near seamlessly adjacent to the corners
folded optics con?guration for system 10 Where users Would
of neighboring images Within an acceptable tolerance. If lens
imperfections result in, e.g., a 1.6 pixel gap for delta x, then
an appropriate overlap is 1.35 pixels, in order to reduce delta
prefer or may be limited to a smaller “footprint” for the
system 10.
While the invention has been particularly shoWn and
described by the foregoing detailed description, it Will be
x to 0.25 pixel. An overlap of this order is then accommo
dated in the method discussed in FIG. 3 during alignment.
FIG. 5 is a schematic diagram of an embodiment for
alignment controls used according to the teachings of the
65
understood by those skilled in the art that various other
changes in form and detail may be made Without departing
from the spirit and scope of the invention.
US 6,254,239 B1
9
10
adjusting the dimensions of the image projected from
What is claimed is:
1. A method for aligning an image visualization system to
near seamless vieWing, the system comprising a plurality of
projectors mounted on racks and positioned from a vieWing
screen, comprising:
establishing an image position for an image projected for
each of the plurality of projectors With reference to the
vieWing screen;
each of the plurality of projectors to cover the estab
lished image position.
9. The method as set forth in claim 1 Wherein correcting
5
rotating a projector about a lateral aXis of the projector to
Within a predetermined difference in length of a pro
jected image at the image top and image bottom.
10. The method of claim 9 Wherein correcting horiZontal
magnifying the image projected by each of the plurality of
keystoning comprises:
projectors to the vieWing screen to ?ll the established
rotating a projector about a vertical aXis of the projector
to adjust the difference in height at both the left and
right edges of a projected image to Within a predeter
image position to Within substantially one pixel;
centering at a desired location Within an established image
mined piXel alignment.
position the image projected from each of the plurality
11. A method for aligning an image visualiZation system
comprising a plurality of projectors mounted on racks and
positioned from a vieWing screen, comprising:
of projectors to the vieWing screen; and
correcting horiZontal and vertical keystoning effects for
each image projected to the vieWing screen from each
establishing an image position for an image projected
from each of the plurality of projectors With reference
of the plurality of projectors.
2. The method of claim 1 further comprising:
to the vieWing screen;
registering adjacent images projected by each of the
magnifying the image projected by each of the plurality of
plurality of projectors to one another to align edge
piXels of adjacent images Within a piXel distance of
each other.
3. The method as set forth in claim 1 further comprising:
adjusting the vieWing screen to be substantially perpen
dicular to the optical aXis of each of the plurality of
vertical keystoning comprises:
projectors to substantially cover an established image
position for an image projected by each of the plurality
of projectors;
25
establishing a reference image area for a selected image
projected by one of the plurality of projectors by
centering an alignment pattern on a reference aXis; and
projectors.
registering the nearest vertical and horiZontal images
projected to the vieWing screen to the reference image
4. The method of claim 1 further comprising:
adjusting the racks mounting the plurality of projectors to
area.
be substantially parallel to the vieWing screen.
5. The method of claim 4 Wherein adjusting the racks
12. The method of claim 11 further comprising:
registering each of the remaining images projected to the
further comprises:
vieWing screen to the nearest previously registered
establishing the distance, tilt and parallelism of the racks
vertical and horiZontal projected image.
With reference to the vieWing screen.
13. The method of claim 11 Wherein registering the
6. The method of claim 1 further comprising:
establishing an alignment pattern to replicate an image
nearest vertical and horiZontal projected images comprises:
adjusting the projected image in the horiZontal direction
and the vertical direction to bring the projected image
pattern for each projector across a vieWing screen.
7. The method of claim 1 Wherein centering at a desired
Within an alignment tolerance With reference to an
adjacent projected image.
location further comprises:
translating a lens of each of the plurality of projectors in
14. The method of claim 11 further comprising:
correcting horiZontal and vertical keystoning effects for
an X and y direction to align the centerline of an image
projected by a projector With predetermined centering
each image projected by the plurality of projectors to
lines.
the vieWing screen to an established tolerance.
8. The method of claim 1 Wherein magnifying the image
projected by each of the plurality of projectors comprises:
45
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*
*
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UNITED STATES PATENT AND TRADEMARK OFFICE
CERTIFICATE OF CORRECTION
PATENT NO. : 6,254,239 B1
DATED
: July 3, 2001
INVENTOR(S) : Rodney C. Hibner, II et 211.
Page 1 of l
It is certified that error appears in the above-identified patent and that said Letters Patent is
hereby corrected as shown below:
Title page,
Item [75], line 4, after “Hibner, IL”, delete “Collin”, and insert -- Allen --.
Line 5, after “Gangstead,", delete “Dallas”, and insert -- Garland --.
Column 3
Line 20, after the ?rst “by”, delete “rescaling”, and insert -- rescaling --.
Column 5
Line 11, after “(not explicitly shown)”, inse
-- . --.
Signed and Sealed this
Twenty-?fth Day of December, 2001
Arrest:
JAMES E. ROGAN
Arresting Officer
Director of the United States Patent and Trademark Office
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