Note: Descriptions are shown in the official language in which they were submitted.
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Method For Stereoscopic Representation
This invention relates to a method of graphically
displaying additional information which in itself exists as
a two-dimensional representation, in addition to a
stereoscopically displayed space.
With increasing progress in the display oi:
information by means of computers and suitable image
reproduction devices, the stereoscopic display of spaces or
of objects which are present in a space is also becoming
important. Other information - hereinafter called
additional information - frequently has to be displayed in
the field of view of an observer, wherein the same image
reproduction device can advantageously be used.
Thus, for example, a method and a device for the
display of flight guidance information with a three-
dimensional display of the air space comprising at least one
horizon and the precalculated flight path of the aircraft
have become known from EP 0 418 558 A2 and US 5,420,582.
The display of the air space can contain various objects
such as the ground, the take-off and landing runways, or
buildings, which are reproduced either in perspectives on a
flat screen or stereoscopically. So as to be able to take
in other indications at a glance, this known device
comprises the display of various scales on the screen as
additional information. In itself, this additional
information is in fact only two-dimensional, and in a
stereoscopic display of the air space can cause irritation
to the observer - particularly due to additional inclination
movements of the eyes when there is a change of the
observer's attention between the additional information and
objects of the stereoscopic display.
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The object of the present invention is to
facilitate the reception of all the information in a
stereoscopic display of a space, including additional
information which in itself is two-dimensional, and to make
it possible to work with displays of this type in a fatigue-
free manner.
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This object is achieved according to the invention by depicting the additional
information at a
depth of the displayed space which is in a predetermined relationship to the
depth of objects
present in the displayed space.
In essence, the invention can be realised by providing the additional
information with a
parallax, i.e. by displaying it displaced for the left and right eye
corresponding to the plane of
depth in which the additional information is to be displayed. At the same
time, it is not
impossible for spatial attributes (scales, pointers, warning indications) to
be imparted to the
displays of additional information, such as a defined thickness or shading for
example. The
additional information can also be situated in a plurality of planes.
All known and future devices for stereoscopic reproduction are suitable as
image
reproduction devices. Examples thereof include miniature display screens which
are disposed
on the observer's head and which can be observed via an eyepiece, systems with
surrounding
opaque screens in which the left and right eyes alternately observe a display
screen, or
systems comprising polarising spectacles.
The method according to the invention can advantageously be used wherever a
stereoscopically displayed space is observed together with additional
information. One
intended application is for the guidance of a vehicle. In one embodiment of
the invention, the
stereoscopically displayed space is therefore situated in a direction of view
in front of a
vehicle, particularly an aircraft, and contains stereoscopically displayed
objects which
constitute guidance information, and the additional information is displayed
at a depth which
is in a logical relationship with said objects.
If the space, including the objects present therein, is calculated by a
graphics computer in this
embodiment, for example, information is also ultimately present regarding the
importance of
or the attention which should be paid to the objects present in the space.
Thus in a simulated
view from an aircraft, for example, a scale can be displayed in the plane of
the windscreen of
the aircraft to effect an adaptation to conditions of natural light. However,
if the display of an
object, e.g. a landing runway, necessitates particular attention due to the
operating situation, it
may definitely be advisable to depict the scale, including the associated
pointer, at the depth
of the landing strip.
In this embodiment it has proved to be particularly advantageous if the
objects depict a
predictor which denotes the estimated path of the vehicle, and if the depth of
the additional
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information is in the region of the predictor. In this connection, the
predictor preferably
consists of a plurality of parts disposed one behind another, and the depth of
the additional
information is situated in the region of a first part which is situated
nearest to the vehicle.
In the method according to the invention, however, it is not impossible for
the additional
information to be displayed somewhat in front of or behind the object in
question, depending
on the requirements which exist.
In another embodiment of the method according to the invention, the depth of
the additional
information can be varied and is matched to the depth of predetermined objects
in the space.
The additional information, together with spatially fixed objects, can thereby
come closer to
the aircraft and thus to the observer, particularly in a view from an aircraft
in the direction of
travel. At the same time, provision can be made in addition for one or more of
a plurality of
objects in the space to be selected as predetermined objects. This selection
is made with the
aid of information which is likewise stored in a computer. Thus, for example,
a display
which, together with a route marker, comes closer as regards its depth can
jump to a
following route marker when the first route marker moves out of the field of
view.
In one advantageous embodiment of the method according to the invention,
particularly
important additional information is emphasised by displaying it in front of
the screen of a
stereoscopic image reproduction device, namely between the screen and the
observer.
Provision can also be made for particularly important additional information
to be
emphasised by displaying it at a varying depth, preferably with a decreasing
depth (coming
towards the observer).
For example, warning signals can be emphasised particularly clearly in
relation to the other
information which is displayed, optionally by moving them forwards from the
depth of the
image so that they "hit the observer straight in the eye".
Another embodiment of the method according to the invention achieves the
object of
stereoscopically displaying objects situated behind the observer also. Objects
such as these
may be aircraft approaching from behind, for example. In a method for the
display of objects
in addition to a stereoscopically displayed space which is situated in front
of an observer,
whilst the objects are situated behind the observer, this object is achieved
by the objects being
displayed between the observer and the screen of a stereoscopic image
reproduction device.
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In this embodiment, a volume of visibility which comprises the objects and
which extends as
far as the plane of the screen starting from a viewpoint situated behind the
observer is
preferably reduced to a volume of visibility between the observer and the
plane of the screen.
In one method for the stereoscopic display of a space which is situated in the
direction of
view in front of a vehicle, provision is made for the depth of the space to be
displayed
enlarged compared with reality. This method can also be employed with one or
both of the
aforementioned embodiments, and makes it possible to achieve better resolution
of the depth,
particularly of objects which are at a considerable distance.
Examples of embodiments of the invention are explained in greater detail below
and are
illustrated in the drawings, which comprise a plurality of Figures, where:
Figure 1 is a display which serves to explain the invention;
Figure 2 is a schematic illustration which serves to explains the information
in the
display;
Figure 3 is a block circuit diagram of a device for carrying out the method
according to
the invention; and
Figure 4 is a schematic illustration of a further embodiment of the invention.
Identical parts are denoted by identical reference numerals in the Figures.
The flight situation illustrated in the display shown in Figure 1 corresponds
to a landing
approach, wherein the precalculated flight path is displayed with the aid of a
predictor, which
consists of four bodies 1, 2, 3, 4, and with the aid of straight lines 5, 6,
7, 8 as the boundaries
of an approach lane which the aircraft is approaching. On flying further in a
straight line, the
aircraft would land beside the landing runway, which is simply displayed as a
rectangle 9.
A line 10 represents the horizon, and rectangles 11, 12 indicate the pitch
angle by their
distance from the horizon 10 and by the figures which are visible inside the
rectangles. The
ground 13 is provided with a grid 14 which is aligned in a north-south
direction. The sky is
displayed in the form of strips 15, 16, 17 of different shades of colour
(darker and lighter blue,
which are not visible in Figure 1 ), in order to impart further information on
the pitch angle.
The ground 13 is preferably displayed in green or brown. Colours and levels of
brightness are
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provided for the bodies 1 to 4, which are also hereinafter called predictors,
which stand out
against both the sky and the ground.
The other indications which are visible in the display shown in Figure l,
particularly a roll
angle indicator 18, a speed indicator 19, a height indicator 20 and a course
indicator 21, are
known in the art and in particular do not need to be explained in detail to
provide an
understanding of the invention.
The predictor illustrated in Figure 1 comprises bodies 1 to 4 which are
divided into a plurality
of sub-bodies. However, a subdivision by means of individual lines, as has
been effected in
the illustration of Figure 1, is not clearly visible at the given distance of
observation on
account of the limits of resolution of the image reproduction arrangement and
of the human
eye, particularly for those sub-bodies which are the furthest away. In
practice, this division
into sub-bodies is therefore effected by means of the shape thereof or by a
colour progression.
In the side view of an aircraft 21 and of bodies 2, 4 which are transformed
into reality which
is illustrated in Figure 2, the height of the body 2, and of the body on the
left side of the flight
path which is not visible in Figure 2, is selected so that the top edge 22
thereof is situated at
about the eye level of the pilot, whilst the bottom edge thereof assumes the
height of the
contact surface of the wheel 24. A line 26 characterises the depth in the
sense of the distance
from the observer of the indicators 18 to 21.
The display shown in Figure 1 is a perspective representation, but the
invention starts from a
stereoscopic representation. The reproduction of a display such as this -
which is in fact only
possible as a two-dimensional representation anyway in the paper form which is
necessary for
patent applications - is essentially characterised in that two partial images
are generated which
do not differ from each other in the plane of the screen and which differ from
each other by a
greater parallax with increasing distance from the observer (depth). For
example, if the
indicators 18 to 21 are displayed at the same location for each of the partial
images, they
appear to the observer to be at an infinite distance, at the horizon for
example.
However, in the interest of flight guidance with the aid of the predictor l,
it has proved to be
advantageous if the indicators are disposed in the region of depth of the part
25 of the
predictor which is situated nearest to them in each case. The parallax of the
indicators, i.e. the
horizontal displacement of one partial image in relation to the other, is
therefore selected
corresponding to the parallax within the region of depth of the parts 25 of
the predictor facing
the observer.
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In addition to a choice of parallax which
corresponds to the depth, it is necessary to mask objects
situated one behind another according to their depth. For
example, in the display shown in Figure 1 it is assumed that
the approach lane 5 to 8 continues from the landing runway 9
to a point behind the observer. The parts of the approach
lane situated in the foreground of the image are accordingly
situated nearer the observer than are the parts 25 ~~f the
predictor, and are thus also nearer than the indical;ors 18
to 21. The latter, however, are nearer to the observer than
is the horizon, so that they in fact mask the horizon and
are masked in turn by the lines of the approach lane.
The example of an embodiment shown in Figure 3 is
represented as a block circuit diagram. However, this does
not mean that the device illustrated is limited to a form of
production comprising individual circuits corresponding to
the blocks shown. Rather, the device can be produced in a
particularly advantageous manner by means of highly
integrated circuits. Digital signal processors can then be
used, which when suitably programmed perform the pro<~essing
steps illustrated in the block circuit diagram.
In the embodiment of a device for carrying out the
method according to the invention which is shown in
Figure 3, a graphics processor 31 is provided for the
display of the air space and of objects situated therein,
including the predictor 1 to 4 and the approach lane :~ to 8
(Figure 1). The graphics processor generates a left <~nd a
right partial image which are each stored in a memory 32, 33
and are fed to image reproduction devices 34, 35. The: image
reproduction devices 34, 35 can be observed by the left eye
38 and by the right eye 39, respectively, of an observer via
eyepieces 36, 37.
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In the devices 40, 41, the signals L, R which are
generated by the graphics processor 31 are combined with
signals L', R' which are generated by a further graphics
processor 42. The latter serves to generate the indicators
18 to 21. The elements which are necessary for thi;~ purpose
are taken from a memory 43, whilst the quantities to be
indicated (altitude, flying speed, location, etc.) ~~re
supplied by sensors 44 to 46. The further graphics
processor 42 receives information from the graphics
processor 31 on the depth of the indications to be displayed
- and therefore receives information on the depth of the
parts 25 of the predictor for the display shown in Figure 1.
For example, if in a different flight situation an indicator
relating to the landing runway 9 is generated by the
graphics processor 42, the depth of the landing runway 9 is
communicated by the graphics processor 31 to the furi:her
graphics processor 42. In accordance with this information,
this indicator is then displayed beside or above the landing
runway.
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The embodiment of the method according to the invention which is schematically
illustrated in
Figure 4 enables objects to be made visible, for example aircraft, which are
situated outside
the volume of visibility ~3 of an observer 51 and which in particular are
situated behind the
observer. The volume of visibility 53 results from the distance of observation
of the observer
51 from the screen 52 and from the size of the screen and the scale of the
displayed space. In
the embodiment shown in Figures 1 and 2, the display of the predictor 2, 4 and
of the
indicators 26, amongst others, are situated inside the volume of visibility.
An imaginary observer 54 situated behind can register a volume of visibility
55 in which an
aircraft 56 is located. The position and location of the aircraft 56 are
transmitted to the aircraft
in which the observer 51 is situated by measures which are known in the art,
such as radar
monitoring, and such as communications systems between the two aircraft and
between the
aircraft and ground stations. The volume of visibility 55, including the
aircraft 56, is
projected into a diminished volume of visibility 55' between the observer 51
and the screen
52. Instead of the aircraft 56, the latter includes an aircraft symbol 56'
which reproduces the
position of the aircraft inside the volume of visibility 55 and its location.
