U.S. patent application number 09/882477 was filed with the patent office on 2001-10-25 for augmented imaging using a silhouette to improve contrast.
Invention is credited to Melville, Charles D..
Application Number | 20010033366 09/882477 |
Document ID | / |
Family ID | 21739539 |
Filed Date | 2001-10-25 |
United States Patent
Application |
20010033366 |
Kind Code |
A1 |
Melville, Charles D. |
October 25, 2001 |
Augmented imaging using a silhouette to improve contrast
Abstract
An augmented display includes an image display source and a
silhouette display source. The image display source generates a
virtual image to be perceived by a viewer. The silhouette display
source occurs in the path of the background light. The silhouette
display source generates a mask corresponding to the image content
of the image display. The mask is a darkened area reducing or
blocking background light. As the light from the virtual image is
overlaid onto the background, there is less background light in the
portion where the image appears.
Inventors: |
Melville, Charles D.;
(Issaquah, WA) |
Correspondence
Address: |
Steven P. Koda, Esq.
KODA LAW OFFICE
P.O. Box 10057
Bainbridge Island
WA
98110
US
|
Family ID: |
21739539 |
Appl. No.: |
09/882477 |
Filed: |
June 13, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09882477 |
Jun 13, 2001 |
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09569379 |
May 11, 2000 |
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6257727 |
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09569379 |
May 11, 2000 |
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09189738 |
Nov 10, 1998 |
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6220711 |
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09189738 |
Nov 10, 1998 |
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09009759 |
Jan 20, 1998 |
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5913591 |
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Current U.S.
Class: |
353/28 |
Current CPC
Class: |
G02B 27/01 20130101;
G02B 2027/0118 20130101 |
Class at
Publication: |
353/28 |
International
Class: |
G03B 021/26 |
Claims
What is claimed is:
1. A method of presenting an image for viewing by a user,
comprising the steps of: providing a first set of image data to a
flat-panel display; displaying with the flat-panel display a first
image portion corresponding to the first set of image data;
providing a second set of image data; modulating a beam of light
according to the second set of image data; scanning the modulated
beam of light through a predetermined, periodic scan pattern to
produce a second image portion; and superimposing the second image
portion on the first image portion to produce the image as a
combination of the first image portion and second image
portion.
2. The method of claim 1 wherein the flat-panel display is an LCD
panel.
3. The method of claim 1 wherein the beam of light includes light
of a plurality of wavelengths.
4. The method of claim 1 wherein the first image portion is lower
resolution than the second image portion.
5. A method of displaying a combined image including a background
image portion and a local image portion in response to a set of
image data, comprising the steps of: defining the background image
portion from the set of image data; presenting the background image
portion in an image field with a first display device having a
first resolution; defining the local image portion from the set of
image data; presenting the local image portion with a second
display device; and superimposing the local image portion over the
background image portion in the image field.
6. The method of claim 5 wherein the second display device is a
scanning beam display.
7. The method of claim 6 wherein the first display device is a
cathode ray tube.
8. The method of claim 6 wherein the first display device is an LCD
panel.
9. The method of claim 8 wherein the first display device includes
a backlight aligned to the LCD panel.
10. The method of claim 8 wherein the first display device is
aligned to transmit light from a background scene to the image
field.
11. A display comprising: a scanning beam display portion position
to present a first image to a viewer in a viewing field; and an LCD
panel position to present a second image to the viewer in the
viewing field and oriented such that the first image and second
image are overlapped.
12. The display of claim 11 further comprising a data processing
circuit having an input portion for receiving image data, a first
output coupled to the scanning beam display portion, and a second
output coupled to the LCD panel, the data processing circuit being
operative to define the first image and second image from the image
data.
13. The display of claim 11 further comprising combining optics
having a first input aligned to scanning beam display portion, a
second input aligned to the LCD panel, and an output configured for
alignment to a viewer's eye.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of U.S. Pat. of application Ser. No.
09/569,379, filed May 11, 2000, of Charles D. Melville for
"Augmented Imaging Using a Silhouette to Improve Contrast," which
is a continuation of U.S. patent application Ser. No. 09/189,738
filed Nov. 10, 1998 for "Augmented Imaging Using a Silhouette to
Improve Contrast," which is a continuation of U.S. patent
application Ser. No. 09/009,759 filed Jan. 20, 1998 for "Augmented
Imaging Using a Silhouette to Improve Contrast." The content of
such applications are incorporated herein by reference and made a
part hereof.
BACKGROUND OF THE INVENTION
[0002] This invention relates to augmented imaging techniques and
augmented displays.
[0003] An augmented display is a see-through display which overlays
an image onto a background. The overlaid image is a virtual image.
The background is a real world view of the ambient environment. The
overall image is formed by adding light to the background. The
added light corresponds to the virtual image. The virtual image
appears to be transparent because in the display portion where the
image is formed, light from both the virtual image and the
background impinge on the same photoreceptors in the viewer's eye.
Because light from both light sources impinge on the same
photoreceptors, it may be difficult for the viewer to distinguish
between the image and the background. This invention is directed
toward a method and apparatus for improving the contrast of an
augmented display.
SUMMARY OF THE INVENTION
[0004] According to the invention, an augmented display includes an
image display source and a silhouette display source. The image
display source generates a luminous virtual image to be perceived
by a viewer. The silhouette display source occurs in the path of
the background light.
[0005] According to one aspect of this invention, the silhouette
display source generates a mask corresponding to the image content
of the image display. The mask is a darkened area reducing or
blocking background light. As the light from the virtual image is
overlaid onto the background, there is less background light in the
portion where the image appears. In one embodiment the mask shape
and size is the same as the virtual image content created by the
image display. In effect, the mask is a dark version of the virtual
image content. In another embodiment the mask encompasses more area
than just the image area of the virtual image
[0006] An advantage of using a silhouette mask is that the content
of the virtual image appears to be solid, rather than transparent.
The virtual image overlays and eclipses the background objects.
[0007] According to another aspect of the invention, in a telescope
embodiment the silhouette display source is located at the
intermediate image plane of the telescope. An advantage of locating
the silhouette display source at the intermediate image plane is
that the darkened silhouette is in focus. There is a sharp edge
between the background and the silhouette mask. Another advantage
is that the virtual image appears more real when the mask is in
focus.
[0008] These and other aspects and advantages of the invention will
be better understood by reference to the following detailed
description taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a block diagram of a conventional augmented
display;
[0010] FIG. 2 is an optical schematic of an augmented display
according to one embodiment of this invention;
[0011] FIG. 3 is an optical schematic of an augmented display
according to another embodiment of this invention;
[0012] FIG. 4 is a diagram of an image generated by the display of
FIG. 1;
[0013] FIG. 5 is a diagram of an image generated by the display of
FIGS. 2 or 3 according to an embodiment of this invention;
[0014] FIG. 6 is a diagram of the silhouette display 26 of FIGS. 2
or 3 with a masked region shown according to an embodiment of this
invention;
[0015] FIG. 7 is a diagram of an image generated by the display of
FIGS. 2 or 3 according to an embodiment of this invention;
[0016] FIG. 8 is a diagram of the silhouette display 26 of FIGS. 2
or 3 with an alternative masked region shown according to an
embodiment of this invention; and
[0017] FIG. 9 is an optical schematic of a virtual retinal display
embodiment of the virtual image source of FIGS. 2 and 3.
DESCRIPTION OF SPECIFIC EMBODIMENTS
[0018] Overview
[0019] FIG. 1 shows a block diagram of a conventional augmented
display apparatus 10. The display apparatus 10 includes a generated
image source 12 and a beamsplitter 14. The image source 12 includes
a lens 13 and an image plane generator 15. Light is received at the
beamsplitter 14 from the image source 12 and from the outside
ambient environment 16. The light from each passes through the
beamsplitter and reaches a viewer's eye E. In effect the image
generated by the image source 12 is overlaid onto the background
view of the ambient environment.
[0020] FIG. 2 shows an optical schematic diagram of an augmented
display 20 according to an embodiment of this invention. The
display 20 includes a virtual image display 22, a silhouette
display 26, a controller 50, a beamsplitter 24 and a mirror 28. The
display 20 receives an image signal 51, such as an RGB signal, NTSC
signal, VGA signal or other formatted color or monochrome video or
image data signal, from an image signal source 19. A virtual image
signal 17 and a silhouette image signal 52 are derived from the
image signal 51 at the controller 50. The virtual image signal 17
is input to the virtual image display 22 which in response
generates light for forming a virtual image. The silhouette image
signal 52 is input to a silhouette display 26 which in response
generates a silhouette image. The virtual image display 22 is a
flat panel display, CRT monitor, or virtual retinal display. Light
defining a virtual image is emitted from the virtual image display
22 and passes through the beamsplitter 24 before impinging on the
viewer's eye E. The silhouette display 26 is a liquid crystal
display panel or another transparent display device which passes
background light from the ambient environment. Background light 16
passes through the silhouette display 26 and beamsplitter 24, then
impinges on the viewer's eye E. The concave mirror 28 receives some
of the virtual image light from the beamsplitter. The mirror 28
reflects such light back into the beamsplitter and on to the
viewer's eye E to increase the amount of light reaching the eye E.
The mirror acts like a lens to locate the virtual image at the same
apparent distance as the real image.
[0021] FIG. 3 shows an alternative embodiment of an augmented
display 20'. Components serving a similar function as in display 20
are given the same part numbers. The display 20' includes a virtual
image source 22, such as a flat panel display, CRT monitor, or
virtual retinal display. In addition, the display 20' includes a
beamsplitter 24, a silhouette display 26, an objective lens 32, an
eyepiece 34 and a controller 50. Background light passes through
the objective lens 32 and is focused to an intermediate image plane
which is concurrent with the silhouette display 26. The silhouette
display 26 is normally transparent and passes the focused
background light. The background light passes through the
silhouette display 26, beamsplitter 24, and an eyepiece 34, then
impinges on the viewer's eye E. Light defining a virtual image is
emitted from the virtual image source 22 and passed through the
beamsplitter 24 and eyepiece 34 before impinging on the viewer's
eye E.
[0022] Operation
[0023] FIG. 4 shows an image I perceived by a viewer for the
conventional display 10 of FIG. 1. An image 36 is overlaid onto a
background image 38. Note that the overlaid image 36 is
transparent. FIG. 5 shows an image I' perceived by a viewer for the
displays 20 or 20' of FIGS. 2 and 3 according to this invention.
Although the same image I' is depicted for each display 20, 20', in
practice the image from display 20 will have a fuzzy, out of focus
dark area around the overlaid image I'. The image I' from display
20' will have a sharper, in focus border at the overlaid image
I'.
[0024] A virtual image 40 is generated by the virtual image display
22. Concurrently a background image 42 formed by background light
from the ambient environment is passed through the silhouette
display 26. In effect the virtual image 40 is overlaid onto the
background image 42. According to one aspect of this invention, the
silhouette display 26 is darkened within a select region 44 (see
FIG. 6) to reduce or preclude background light from passing through
such select region 44. Such select region 44 corresponds to the
virtual image 40 and serves as a mask 46. In one embodiment the
mask 46 coincides with the virtual image 40 (see FIG. 5). In
another embodiment the mask 46 encompasses more area than just the
virtual image 40 (see FIGS. 7 and 8).
[0025] To define the virtual image 40, the virtual image display 22
receives image data signals 51 from a computer or other signal
source 19. In one embodiment a controller 50 for the silhouette
display 26 also receives such image data signals 51. In response
the controller 50 generates a masking signal 52 which darkens a
select region 44 of the silhouette display 26 to define the
corresponding mask 46. In one embodiment a pixel to pixel mask 46
(see FIG. 6) is generated, in which for each pixel of the virtual
image 40 there is a corresponding pixel darkened in the silhouette
display 26. In another embodiment, in addition to pixel to pixel
masking, additional pixels on the silhouette display 26 are
darkened to mask other portions within or around the virtual image
40 (see FIG. 8).
[0026] Although the images shown in FIGS. 5 and 7 include only one
virtual image 40 and one mask 46, in alternative embodiments there
are multiple images 40 and masks 46 viewable at a given time.
Similarly, although only one mask is shown in each of FIGS. 6 and
8, in alternative embodiments multiple darkened regions 44 and
masks 46 are formed.
[0027] In one embodiment the silhouette display 26 has the same
pixel resolution as the virtual image source display 22. In another
embodiment the silhouette display 26 has a differing resolution
(e.g., lower or higher resolution) than the virtual image display
22. For varying resolution, the mapping of the virtual image 40 to
the mask 46 differs than one pixel to one pixel. For every pixel of
the virtual image display 22, there is at least one pixel of the
silhouette display 26 which is darkened. However, the pixel
darkened for the silhouette display 26 may encompass one or more
pixels of the image display 22 (e.g., where silhouette display 26
has lower resolution than the virtual image display 22). According
to one embodiment the silhouette display 26 is formed by a
transparent liquid crystal display (`LCD`) panel. The LCD panel is
addressable to pixel precision. When a pixel is activated the
region of the pixel on the panel darkens reducing or precluding
background light from passing.
[0028] Although the controller 50 is shown to receive the image
data signal 51, in an alternative embodiment the processor
generating the image data signal 51 for the display 22 also serves
as the controller for generating the masking signal 52.
[0029] Virtual Retinal Display
[0030] FIG. 9 is a block diagram of a virtual retinal display 22
which generates and manipulates light to create color or monochrome
images having narrow to panoramic fields of view and low to high
resolutions. The display 22 includes an image data interface 111
which receives a virtual image signal 17 from the controller 50
(see FIGS. 2 or 3). The image data interface 111 generates signals
for controlling a light source 112. Light modulated with video
information corresponds to image elements (e.g., image pixels)
which are scanned onto the retina of a viewer's eye E to produce
the perception of an erect virtual image.
[0031] The virtual image signal 17 is a video or other image
signal, such as an RGB signal, NTSC signal, VGA signal or other
formatted color or monochrome video or graphics signal. An
exemplary embodiment of the image data interface 111 extracts color
component signals and synchronization `SYNCH` signals from the
received image signal. In an embodiment in which an image signal
has embedded red, green and blue components, the red signal is
extracted and routed to a modulator for modulating a red light
point source output. Similarly, the green signal is extracted and
routed to a modulator for modulating the green light point source
output. Also, the blue signal is extracted and routed to a
modulator for modulating the blue light point source output.
[0032] The light source 112 includes one or more point sources of
light. For generating a monochrome image a single monochrome
emitter typically is used. For color imaging, multiple light
emitters (e.g., red light point source, green light point source,
and blue light point source) are used. Preferably the emitted light
is spatially coherent. Exemplary light emitters include colored
lasers, laser diodes or light emitting diodes (LEDs). Although LEDs
typically do not output coherent light, lenses are used in one
embodiment to shrink the apparent size of the LED light source and
achieve flatter wave fronts. In a preferred LED embodiment a single
mode monofilament optical fiber receives the LED output to define a
point source which outputs light approximating coherent light.
[0033] Where the light emitters are externally modulated, the
display device 22 also includes a modulator responsive to an image
data signal received from the image data interface 111. The
modulator modulates the visible light emitted by the light emitters
to define image content for the virtual imagery scanned on a
viewer's eye. The modulator is an acoustooptic, electrooptic, or
micro-electromechanical modulator. Additional detail on these and
other light source 112 embodiments are found in U.S. patent
application Ser. No. 08/437,818 for "Virtual Retinal Display with
Fiber Optic Point Source" filed May 9, 1995, and incorporated
herein by reference. According to alternative embodiments, the
light emitters or the light generated by the point sources are
modulated to include red, green, and/or blue components at a given
point (e.g., pixel) of a resulting image. Respective beams of the
point sources are modulated to introduce color components at a
given pixel.
[0034] The optics subsystem 114 receives the light output from the
light source 112, either directly or after passing through the
scanning subsystem 116. In some embodiments the optical subsystem
collimates the light. In another embodiment the optics subsystem
converges the light. Left undisturbed the light converges to a
focal point then diverges beyond such point. As the converging
light is deflected, however, the focal point is deflected. The
pattern of deflection defines a pattern of focal points. Such
pattern is referred to as an intermediate image plane.
[0035] The emitted light 136 is deflected along a prescribed
pattern, such as a raster pattern, by a scanner subsystem 116. In
an alternative embodiment another display format such as vector
imaging can be used for scanning image elements onto the eye. In
one embodiment the scanning subsystem 116 receives a horizontal
deflection signal and a vertical deflection signal derived from the
image data interface 111. The scanning subsystem 116 is located
after the light source 112, either before or after the optics
subsystem 114. In one embodiment the scanning subsystem 116
includes a resonant scanner for performing horizontal beam
deflection and a galvanometer for performing vertical beam
deflection. The horizontal scanner receives a drive signal having a
frequency defined by the horizontal synchronization signal
extracted at the image data interface 111. Similarly, the
galvanometer serving as the vertical scanner receives a drive
signal having a frequency defined by the vertical synchronization
signal VSYNC extracted at the image data interface 111. Preferably,
the horizontal scanner has a resonant frequency corresponding to
the horizontal scanning frequency. In alternative embodiments, the
scanning subsystem 116 instead includes acousto-optical deflectors,
electro-optical deflectors, rotating polygons or galvanometers to
perform the horizontal or vertical light deflection. In some
embodiments, two of the same type of scanning device are used. In
other embodiments different types of scanning devices are used for
the horizontal scanner and the vertical scanner.
[0036] The light emitted from the display 22 is deflected by the
beamsplitter 24 (see FIGS. 2 and 3) and directed toward a viewer's
eye E. In the embodiment of FIG. 3 an eyepiece 34 also is
included.
[0037] Meritorious and Advantageous Effects
[0038] An advantage of using a silhouette mask is that the content
of the virtual image appears to be solid, rather than transparent.
The virtual image overlays and eclipses the background objects. An
advantage of locating the silhouette display source at the image
plane is that the darkened silhouette is in focus. There is a sharp
edge between the background and the silhouette mask. Another
advantage is that the virtual image appears more real when the mask
is in focus.
[0039] Although preferred embodiments of the invention have been
illustrated and described, various alternatives, modifications and
equivalents may be used. Therefore, the foregoing description
should not be taken as limiting the scope of the inventions which
are defined by the appended claims.
* * * * *