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Claims  |
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What is claimed is:
1. Virtual object display apparatus, comprising:
environment information memory means for storing environment information,
including a position, a posture and a motion rule, for a plurality of
objects in a virtual space, wherein the motion rule represents how each of
the plurality of objects moves in the virtual space;
view information memory means for storing view information defining the
extent of a view area from a viewpoint in the virtual space;
visibility decision means for determining whether each of the plurality of
objects is visible from the viewpoint in accordance with the environment
information and the view information, whenever motions of the plurality of
objects are updated;
motion generation means for generating motion for each of the plurality of
objects in the virtual space, wherein the motion of each of the objects is
simplified if the object is not visible from the viewpoint, and the motion
of the object is generated using the position and the posture of the
object if the object is newly visible from the viewpoint after a
simplified motion; and
display means for displaying the motion of each of the objects visible from
the viewpoint.
2. Virtual object display apparatus according to claim 1,
wherein the visibility decision means deteremines the object is visible if
the object is at least partially visible from the viewpoint.
3. Virtual object display apparatus according to claim 1,
wherein the view information includes a viewpoint coordinate, a reference
point coordinate, a horizontal view angle, a vertical view angle, a
distance between the viewpoint and the nearer clipping plane and a
distance between the viewpoint and the farther clipping plane in a view
coordinate space in the virtual space.
4. Virtual object display apparatus according to claim 3,
wherein the view area comprises a quadrangular pyramid defined by a
direction from the viewpoint coordinate to the reference point coordinate
extending between the nearer clipping plane and the farther clipping plane
in the view coordinate space.
5. Virtual object display apparatus according to claim 4,
wherein the visibility decision means includes means for defining a
bounding box for a selected one of the objects, means for transforming the
bounding box of the selected object in a local coordinate space to view
coordinate space, means for normalizing the view area and the bounding box
of the selected object in view coordinate space, and for deciding whether
the bounding box of the selected object interferes with the normalized
view area.
6. Virtual object display apparatus according to claim 5,
wherein the motion generation means generates motion of the selected object
if the selected object is decided to interfere with the normalized view
area by the visibility decision means, in accordance with motion rule
information of the selected object.
7. Virtual object display apparatus according to claim 6,
wherein the display means displays the motion of the selected object which
is projected on one surface of the normalized view area corresponding to a
display surface of the display means.
8. Virtual object display apparatus according to claim 1,
wherein the environment information of each object includes for each
element an element name, a position, a posture, a pointer to figure
information and a parent name in local coordinate space.
9. Virtual object display apparatus according to claim 5,
wherein the figure information includes a pointer address, a polygon name,
peak coordinates for each polygon name and color information for each
polygon name.
10. Virtual object display apparatus, comprising:
environment information memory means for storing environment information,
including a motion rule, for a plurality of objects in a virtual space,
wherein the motion rule represents how each of the plurality of objects
moves in the virtual space;
view information memory means for storing view information defining the
extent of a view area from a viewpoint in the virtual space;
attention degree calculation means for calculating an attention degree for
each of the plurality of objects in accordance with the environment
information and the view information, wherein the attention degree is
computed from a mental attention degree based on a casting of the object;
motion generation means for generating relatively complex motion for the
object if the attention degree of the object is relatively high, and for
generating relatively simple motion for the object if the attention degree
of the object is relatively low, in accordance with the motion rule; and
display means for displaying the motion of each of the objects generated by
the motion generation means.
11. Virtual object display apparatus according to claim 10,
wherein the attention degree is a ratio of a product of a distance between
the viewpoint and the nearer clipping plane and a visible state value to a
distance between the viewpoint and the object.
12. Virtual object display apparatus according to claim 10,
further including environment information selection means for selecting
relatively detailed elements of the object as the environment information
when the attention degree of the object is relatively high, and for
selecting relatively simple elements of the object as the environment
information when the attention degree of the object is relatively low.
13. Virtual object display apparatus according to claim 10,
wherein the motion generation means generates independent motion for each
of the objects for which the attention degree is high, generates motion
for one object for which the attention degree is intermediate and link
there to motions of other ones of the objects for which the attention
degree is intermediate, and generates a billboard image for ones of the
objects for which the attention degree is low.
14. A virtual object display method, comprising the steps of:
storing environment information, including a position, a posture and a
motion rule, for a plurality of objects in a virtual space, wherein the
motion rule represents how each of the plurality of objects is moving in
the virtual space;
storing view information defining the extent of a view area in the virtual
space;
deciding whether each of the plurality of objects is visible in the view
area in accordance with the environment information and the view
information, whenever motions of the plurality of objects are updated;
generating motion for each of the plurality of objects in the virtual
space, wherein the motion of the object is simplified if the object is not
visible in the view area, and the motion of the object is generated using
the position and the posture of the object if the object is newly visible
from the viewpoint after a simplified motion; and
displaying the motion of each of the objects visible in the view area.
15. A virtual object display method, comprising the steps of:
storing environment information, including a motion rule, for a plurality
of objects in a virtual space, wherein the motion rule represents how each
of the plurality of objects moves in the virtual space;
storing view information defining the extent of a view area in the virtual
space;
calculating an attention degree for each of the plurality of objects in
accordance with the environment information and the view information,
wherein the attention degree is computed from a mental attention degree
based on a casting of the object;
generating relatively complex motion for the object if the attention degree
of the object is relatively high, and relatively simple motion for the
object if the attention degree of the object is relatively low, in
accordance with the motion rule; and
displaying the motion of each of the objects generated at the generating
step.
16. A computer-readable memory comprising:
instruction means for causing a computer to store environment information,
including a position, a posture and a motion rule, for a plurality of
objects in a virtual space, wherein the motion rule represents how each of
the plurality of objects moves in the virtual space;
instruction means for causing a computer to store view information of the
extent of a view area in the virtual space;
instruction means for causing a computer to determine whether each of the
plurality of objects is visible in the view area in accordance with the
environment information and the view information, whenever motions of the
plurality of objects are updated;
instruction means for causing a computer to generate motion for each of the
plurality of objects in the virtual space, wherein the motion of the
object is simplified if the object is not visible in the view area, and
the motion of the object is generated using the position and the posture
of the object if the object is newly visible from the viewpoint after a
simplified motion; and
instruction means for causing a computer to display the generated motion of
each of the objects visible in the view area by the visibility
determination.
17. A computer-readable memory comprising:
instruction means for causing a computer to store environment information,
including a motion rule, for a plurality of objects in a virtual space,
wherein the motion rule represents how each of the plurality of objects
moves in the virtual space;
instruction means for causing a computer to store view information defining
the extent of a view area in the virtual space;
instruction means for causing a computer to calculate an attention degree
for each of the plurality of objects in accordance with the environment
information and the view information, wherein the attention degree is
computed from a mental attention degree based on a casting of the object;
instruction means for causing a computer to generate relatively complex
motion for the object if the attention degree of the object is relatively
high, and relatively simple motion for the object if the attention degree
of the object is relatively low, in accordance with the motion rule; and
instruction means for causing a computer to display the generated motion of
each of the objects. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a virtual object display apparatus and
method to display motions of objects, including humans at high speed
usings computer-graphics system.
2. Description of the Related Art
Conventionally, in the case of displaying action of an object, having
plural elements connected by a link structure, using computer-graphics,
calculation of inverse-kinematics or physical rules is executed for each
object. If the motion of the object is displayed at real time while the
motion of the object is simulated, the calculation-load causes a decrease
of an update-rate of drawing the motion of the object on the display
screen in proportion to a number of the objects.
In such a case, a human model or a model of some other living things is
represented as an object composed of a plurality of elements (a head, a
body, a right arm, a left arm, a right hand, a left hand, a right leg, a
left leg, a right foot, a left foot). The plurality of elements are
connected by a link structure. Therefore, in the case of displaying the
action of the object by computer-graphics, a few objects or simple actions
of the object are only displayed because of the above-mentioned
calculation-load.
In the case of displaying a lot of objects, it is impossible to draw
coordinate points of the objects on the display screen in real time. In
this case, drawing of the objects is executed by unit of frame in non-real
time. After creating all frames, the user watches the frames by playing as
a video image. However, in this method, it is impossible for the user to
interactively designate an motion of the object on the display screen. For
example, in the case of simulation-display of the flow of a lot of humans
in the street, it is only possible for the user to watch the action of
many humans without interactive designation.
In short, in the case of displaying the action of a lot of objects using
computer-graphics, it takes a long time to draw the motion of a lot of
objects on the display screen because of the calculation-load of the
motion of each object. Therefore, it is impossible for the user to watch
the motion of the objects in real-time.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a virtual object
display apparatus and method to suitably display the motion of objects in
real-time according to user's view information.
According to the present invention, there is provided a virtual object
display apparatus, comprising: environment information memory means for
storing environment information, including position, of a plurality of
objects in a virtual space; view information memory means for storing view
information of the extent of a view area from a viewpoint in the virtual
space; visibility decision means for determining whether each of the
plurality of objects is visible from the viewpoint in accordance with the
environment information and the view information; motion generation means
for generating motion for each of the plurality of objects in the virtual
space in accordance with a decision result of the visibility decision
means; and display means for displaying the motion of each of the objects
generated by the motion generation means.
Further in accordance with the present invention, there is provided a
virtual object display apparatus, comprising: environment information
memory means for storing environment information of a plurality of objects
in a virtual space; view information memory means for storing view
information of the extent of a view area from a viewpoint in the virtual
space; attention degree calculation means for calculating an attention
degree for each of the plurality of objects in accordance with the
environment information and the view information; motion generation means
for generating action for each of the plurality of objects in the virtual
space in accordance with the attention degree calculated by the attention
degree calculation means; and display means for displaying the action of
each of the objects generated by the action generation means.
Further in accordance with the present invention, there is provided a
virtual object display method, comprising the steps of: storing
environment information, including position, of a plurality of objects in
a virtual space; storing view information of the extent of a view area in
the virtual space; deciding whether each of the plurality of objects is
visible in the view area in accordance with the environment information
and the view information; generating motion for each of the objects in the
virtual space in accordance with a decision result at the deciding step;
and displaying the action of each of the the objects generated at the
generating step.
Further in accordance with the present invention, there is provided a
virtual object display method, comprising the steps of: storing
environment information of a plurality of objects in a virtual space;
storing view information of the extent of a view area in the virtual
space; calculating an attention degree for each of the plurality of
objects in accordance with the environment information and the view
information; generating motion for each of the plurality of objects in the
virtual space in accordance with the attention degree calculated at the
calculating step; and displaying the motion of each of the objects
generated at the generating step.
Further in accordance with the present invention, there is provided a
computer-readable memory comprising: instruction means for causing a
computer to store environment information, including position, of a
plurality of objects in a virtual space; instruction means for causing a
computer to store view information of the extent of a view area in the
virtual space; instruction means for causing a computer to determine
whether each of the plurality of objects is visible in accordance with the
environment information and the view information; instruction means for
causing a computer to generate motion for each of the objects in the
virtual space in accordance with a result of the visibility determination;
and instruction means for causing a computer to display the generated
motion of each of the objects.
Further in accordance with the present invention, there is provided a
computer-readable memory comprising: instruction means for causing a
computer to store environment information of a plurality of objects in a
virtual space; instruction means for causing a computer to store view
information of the extent of a view area in the virtual space; instruction
means for causing a computer to calculate an attention degree for each of
the plurality of objects in accordance with the environment information
and the view information; instruction means for causing a computer to
generate motion for each of the plurality of objects in the virtual space
in accordance with the attention degree; and instruction means for causing
a computer to display the generated motion of each of the object.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a first embodiment of the present
invention.
FIG. 2 is a schematic diagram of content of view information.
FIG. 3 is a schematic diagram of a view area defined by the view
information.
FIG. 4 is a schematic diagram of content of environment information.
FIG. 5 is an example of object elements of the environment information.
FIG. 6 is an example of a tree structure of the object elements.
FIG. 7 is a schematic diagram of content of figure information.
FIG. 8 is an example of action rule information.
FIG. 9 is an example of a bounding box of an object.
FIG. 10 is a schematic diagram of the view area and the bounding box of the
object in view coordinate space.
FIG. 11 is a schematic diagram of the view area and the bounding box of the
object in normalized view coordinate space.
FIG. 12 is a flow chart according to the first embodiment of the present
invention.
FIG. 13 is an example of the relation between many objects and the view
area.
FIG. 14 is a schematic diagram of a second embodiment of the present
invention.
FIG. 15 is a flow chart according to the second embodiment of the present
invention.
FIG. 16 is a schematic diagram of a third embodiment of the present
invention.
FIG. 17 is a schematic diagram of selection of the environment information.
FIG. 18 is an example of a tree-structure of the object elements for
selection of the environment information.
FIG. 19 is a flow chart according to the third embodiment of the present
invention.
FIG. 20 is a schematic diagram of the relation between motion of a crowd
and an attention degree.
FIG. 21 is a schematic diagram of the relation between the environment
information of the crowd and the attention degree.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the present invention are described below with reference to
the drawings.
FIG. 1 is a schematic diagram of a virtual object display apparatus
according to a first embodiment of the present invention. The virtual
object display apparatus of the first embodiment includes an input section
11, a view information memory section 12, an environment information
memory section 13, an motion rule information memory section 14, a
visibility decision section 15, an motion generation section 16 and a
display section 17.
First, the view information for visible objects in a virtual environment
and environment information of the objects in the virtual environment are
supplied through the input section 11. The view information memory section
12 stores the view information. FIG. 2 is a schematic diagram of content
of the view information. The view information includes of a view point
coordinate, a reference point coordinate, a horizontal view angle, a
vertical view angle, the distance between the viewpoint and the nearer
clipping plane and the distance between the viewpoint and the farther
clipping plane in view coordinate space. FIG. 3 is a schematic diagram of
the view area defined by the view information shown in FIG. 2. The view
area is represented as a quadrangular pyramid based on axes of view
coordinates in FIG. 3. In short, the view area corresponds to the view
perceived by the eyes of the user.
The environment information memory section 13 stores the environment
information of the objects. FIG. 4 is a schematic diagram of content of
the environment information. The environment information includes an
element name, a position, posture, a pointer to figure information and a
parent (element) name. In FIG. 4, the elements are the parts of which one
object consists. Examples of objects are a human, desk, chair and so on.
With respect to elements, in the case of a human, for example, the each
elements can be the head, body, left arm, left hand, right arm, right
hand, left leg, left foot, right leg, right foot. The environment
information of each element includes the parent element and all elements
of one object are connected by physical connection relations
(tree-structure). FIG. 5 is a schematic diagram of the relation between
element name and parent name in the case of a human. FIG. 6 is a schematic
diagram of a tree-structure of the elements forming a human model. In this
example, the body is a center element, and other elements (head, arm, leg)
are connected to the body. In short, the element whose parent is "WORLD"
is the center element of the object. Each object includes one center
element. The position and the posture of the environment information are
values in the local coordinates of the parent element. FIG. 7 is a
schematic diagram of content of figure information. The figure information
includes a polygon name, vertexes and color information of each polygon. A
pointer to figure information in FIG. 4 corresponds to the address of each
item of figure information in FIG. 7.
The motion rule information memory section 14 previously stores motion data
of each object (element). FIG. 8 is an example of content of the motion
rule by unit of object.
The visibility decision section 15 decides whether each object interferes
with the view area according to the view information and the environment
information. In this case, it is first decided whether or not the center
element interferes. Then, other elements are traced along the
tree-structure of the object from the center element, and in sequence,
each element is decided to interfere or not. If an element is decided to
interfere with the view area, the element is decided to be visible. For
example, in FIG. 5 and FIG. 6, the element "BODY" is decided to be visible
or not because the parent name is "WORLD". Then, each descending element,
such as "HEAD" or "LEFT UPPER ARM " is decided to be visible or not
because the parent name is "BODY". This decision processing is repeated by
tracing along the tree-structure until at least one visible element is
found among all elements of the object.
An example of the visibility decision process for an object is explained
with reference to FIG. 9, FIG. 10 and FIG. 11. FIG. 9 is a schematic
diagram of a bounding box of the object. In the case of the visibility
decision of each element, it is decided whether or not the bounding box of
each element interferes with the view area. The bounding box is a
rectangular parallelepiped which circumscribes around the element and each
surface of the bounding box is perpendicular to one of X,Y,Z axes of the
local coordinates.
FIG. 10 is schematic diagram of the view area and the bounding box of an
element. If at least one vertex of the bounding box of the element is
included in the view area, the element is decided to be visible. In this
case, if the view area is normalized as a cube, the decision of whether a
peak of the element is incleded in the view area is easy to calculate.
FIG. 11 is a schematic diagram of the view area and the bounding box of
the object in normalized view coordinate space. The view area of a
quadrangular pyramid shown in FIG. 10 is normalized as a cube (-1<X,Y,Z<1)
in normalized view coordinates. This normalization results in the shape of
the bounding box of the element becoming a quadranglar pyramid. In this
case, the visibility decision of the object is that at least one vertex
(x,y,z) of the bounding box of the element of the object is satisfied in
normalized view coordinates as follows.
-1<x,y,z<1
First, the vertex coordidnate of the bounding box of the element is
calculated in local coordinates. The vertex coordinate in local
coordinates is transformed to that in the normalized coordinates using
following equations.
VLk=Vk.Mk.V
=Vk.M'k.M'p(k) . . . M'p(p(. . . p(k) . . . )).V
VLk: vertex coordinate in view coordinate system
Vk: vertex coordinate in local coordinate system of element k
M'i: conversion matrix from value in local coordinates of element i to
value in local coordinates of its parent
V: conversion matrix to value in view area coordinates
P(i): element of the parent of the element i
Mk: conversion matrix from value in local coordinates of the element k to
value in global coordinates
##EQU1##
M'i=Rz(ri).Rx(ei)..sub.R y(ai).Tr(Xi,Yi,Zi)
V=Tr(-xv,-yv,-zv).Ry(-.sub..psi.)).Rx(.sub.31 .phi.)
##EQU2##
(Xr,Yr,Zr), (Xv,Yv,Zv): view coordinate
The above equations represent the conversion from the coordinate value in
the local coordinates to the coordinate value in the view coordinates
before normalization.
##EQU3##
Vnv: vertex coordinate in normalized view coordinates VLk (XLk, YLk, ZLk):
vertex coordinates in unnormalized view coordinates
ah, av, Dn, Df: view information
The above equations represent the normalization of the view coordinates.
Next, the motion generation section 16 calculates motion of the object
according to the motion rules stored in the motion rule information memory
section 14. For example, in FIG. 8, the motion of the object whose center
element is "obj 1" is calculated as rotation of 30 rpm centering around
the x-axis of the local coordinate space. As for the object whose center
element is "human 1", the motion of "human 1" walks 30 steps, turns to the
left 90 degree and waits 10 seconds while looking at "object 1" is
generated.
The display section 17 draws the virtual environment as computer graphics
according to the view information and the environment information. First,
the center element of the object whose parent name is "WORLD" is retrieved
from the environment information and other elements connecting to the
center element are retrieved in sequence. Then, the center element and the
other elements of the object are displayed. In this case, the peak
coordinate of each element is projected to the display screen. For
example, in FIG. 11, a surface including oblique lines is represented as a
display screen in the normalized coordinate space. In this case, the peak
coordinate (x,y,z) of each element of the object is transformed to the
plot coordinate (x,y,o) on the display screen. In short, the z-value of
the peak coordinate of the element is ignored because the display surface
is the x-y coordinate plane.
FIG. 12 is a flow chart of processing according to the first embodiment of
the present invention. The processing of high-speed drawing of the first
embodiment will be explained in detail with reference to FIG. 12. First,
the object information and the motion rule information in virtual space
are supplied to the input section 11. The object information is stored in
the environment information memory section 13 and the motion rule
information is stored in the motion rule information memory section 14
(step 1.about.4). Next, the view information describing a user's view of
the virtual environment is supplied to the input section 11. The view
information is stored in the view information memory section 12 (step
5,6). The visibility decision section 15 decides whether the object is
included in the view area or not according to the object information and
the view information (step 7). With respect to use of a decision result of
the visibility decision section 15, if at least one part of the object is
included in the view area, the motion generation section 14 generates
motion of the object in virtual space and updates the object information
stored in the environment information memory section 13 according to the
generated motion information (step 8,9). If all element of the object are
not in the view area, the processing of step 8 and step 9 is omitted. The
processing from step 7 to step 9 is repeated for all objects in the
virtual environment. Last, the object in the view area is displayed
according to the object information updated in the virtual environment
(step 10). Then, the processing from step 5 to step 10 is repeated because
of displaying from a different view point.
FIG. 13 is a schematic diagram of a human model moving in a virtual
environment and the view area to watch the virtual environment. As for
eight human models (A.about.H), actions of the human models (C,D) are
generated because only human models (C,D) are included in the view area.
Accordingly, in this case, the calculation load for generating action of
two human is reduced as one-fourth in comparison with the calculation load
for generating action of eight (all) humans. As a result, the object in
virtual environment is displayed at high speed because the calculation of
actions of objects outside the view area are omitted.
In the first embodiment, the status of motion generation of the object has
one of two conditions, i.e., whether motion of the object is calculated or
not. However, in a second embodiment, an attention degree is set for each
object and the action generation of the object is simplified according to
the attention degree. In a movie filming, there is a method by which depth
of field becomes short because a leading part only of a scene is clearly
visible. In this case, other parts of the scene except for the leading
part get blurred on screen and motion of the other parts is not clearly
visible. In the same way, the motion of a primary object to be obserbed is
clearly displayed and the motions of another objects are more simply
displayed since the other objects are located apart from the primary
object to be obserbed. Accordingly, the time for generating motion is
reduced while the natural appearance of the image is maintained.
FIG. 14 is a schematic diagram of the second embodiment of the present
invention. An attention degree calculation section 18 calculates the
attention degree of each object according to the following equations.
##EQU4##
N: attention degree D: distance between the viewpoint and the object
Bv: visible state value (=1(visible)/o(invisible))
Dn: distance between the viewpoint and the nearer clipping plane
(Xv,Yv,Zv): viewpoint coordinate
(Xn,Yn,Zn): coordinate of n-th object
In this example, for an object located in the field of view, a large value
of attention degree is set for the object if it is near to the viewpoint
and a small value of attention degree is set for the object if it is far
from the viewpoint. As for an object located outside the field of view, an
attention degree of "O" is set for the object. The motion generation
section 14 calculates the motion of the object according to the attention
degree. The motion generation section includes a plurality of motion
generation sections 16-1,16-2, . . . , 16-n which calculate object motion
in proportion to the complexity of the action, where the complexity of
motion is increased as the value of the attention degree increases. As an
example, the motion calculation for a walking object (human model) will be
explained. If the walking object is near to the viewpoint, a dynamic
equation for each element of the walking object is solved and a torque
calculation of each joint of the element is executed to balance the
movement of each element for walking (motion level 1). If the walking
object is more distant from the viewpoint, a rotating angle the shoulder,
groin joint and knee and a move distance of the body are only calculated
(action level 2). If the walking object is far from the viewpoint, the
moving distance of the object is only calculated (action level 3). In the
case of motion level 1, control the calculation for controlling the
walking of the object is executed by unit of 1 loop. Accordingly, the
calculation load for motion level 1 is the largest among the three action
levels. However, a well-balanced walking motion of the object is
displayed. In the case of action level 2, angle data of each joint by
units of predetermined time is prepared and the rotating angle of each
joint is calculated according to the angle data. The calculation load for
motion level 2 is smaller than that of level 1 and each joint of the
object is moved mechanically. In the case of motion level 3, the next
reached position is calculated according to movement speed and calculation
load for action level 3 is small.
FIG. 15 is a flow chart of processing of the second embodiment. Steps
1.about.6 of the second embodiment are the same as those of the first
embodiment in FIG. 12. Following step 6, the attention degree calculation
section 18 calculates the attention degree N according to the view
information and the environment information (step 7). One of the motion
generation sections 1.about.n generates the motion of the object according
to the attention degree N calculated at step 7 (step 8). Plural thresholds
T1.about.Tn corresponding to each motion generation are previously set.
The attention degree N is compared with threshold T.about.Tn in sequence
and one of the motion generation sections 1.about.n is selected. Steps 9
and 10 are the same as those of the first embodiment in FIG. 12.
Accordingly, in the second embodiment, the motion generation is simplified
in accordance with the attention degree of each object.
Next, a modification of the second embodiment will be explained. In the
modification, a method for calculating the attention degree is changed to
calculate its more effective value. Therefore, the schematic diagram and
the flow chart of the modification is the same as those of the second
embodiment. The equation for calculating the attention degree according to
the modification is as follows.
##EQU5##
N: attention degree Nm: mental attention degree
Np: physical attention degree
Nm=g(Ci, Mi, Hi, Ri, Si)
Ci: casting of object i
##EQU6##
Mi: complexity of action of object i Hi: conspicuous degree of color of
object i
Ri: undaily degree of object i
Si: moving speed of object i
Np=h(D(i), A(i),O(i))
D(i): distance function of object i from viewpoint
##EQU7##
Xv,Yv,Zv: viewpoint coordinate position Xi,Yi,Zi: object coordinate
position
A(i): angle of gravity of object i from a view direction
O(i): overlap function of object i
##EQU8##
Therefore, in the modification, the motion generation is simplified
according to the effective attention degree based on the mental attention
degree.
In the case that motion of the object consists of connected plural
elements, the calculation load of motion generation is reduced as the
number of the elements becomes small. In the above-described embodiment,
the structure of elements of the object are fixed. However, in the third
embodiment, structure of elements of the objects is changed according to
the attention degree. FIG. 16 is a schematic diagram of the flow control
apparatus of the third embodiment, in which an environment information
selection section 19 is added to the apparatus of the second embodiment.
The environment information selection section 19 changes the element name
of the parent in the environment information according to the attention
degree. In short, the object to be watched in the view area is changed. In
this case, if the value of the attention degree is low, the number of the
elements of the object is changed to be small.
FIG. 17 is an example of change of the environment information. In FIG. 17,
the elements of a B type human represent a simplified version of elements
of an A type human. By changing the parent name, the structure of the
human model is changed from A type to B type. FIG. 18 shows the structures
of both the A type human and B type human. More particularly, "BODY A" is
selected before change. The parent of "BODY A" is "HUMAN" (center-upper
arrow in FIG. 17) and the parent of "BODY B" is "NULL" (center-lower arrow
in FIG. 17). As a result, the human-model consists of "BODY A". After
change, the parent of "BODY A" is "NULL" (right-upper arrow in FIG. 17)
and parent of "BODY B" is "HUMAN" (right-lower arrow in FIG. 17). As a
result, the human-model consists of "BODY B". FIG. 19 is a flow chart of
processing of the third embodiment. The steps except for step 8 are same
as those of the second embodiment in FIG. 15. The environment information
selection section 19 changes the element name of the parent in the
environment information stored in the environment information memory
section (step 8). In short, the object structure is changed according to
the attention degree. Accordingly, the calculation load for action
generation is reduced because the object structure is changed.
In the third embodiment, plural environment information is previously
prepared for one object and suitable environment information is selected
according to the attention degree. However, in a modification of the third
embodiment, pl | | |
