JPH09115002A - Device and method for transforming coordinate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an object from being unnaturally deformed. SOLUTION: When deforming an object, scaling circuits 1, 5 and 6 respectively scale the local coordinates of an arm 2, body and head while using scaling matrixes Sarm2 , Sbody and S. The local coordinates of the arm 2 are scaled by the Sarm2 and transformed into coordinates on a large area coordinate system by three coordinate transforming circuits 2-1, 3-1 and 4-1. At such a time, even when the arm 2 is accompanied with rotations, the scaling is performed while considering the rotations. Thus, even when the arm of the object is rotated, for example, the object is prevented from being unnaturally deformed such as from changing the length of that arm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate transformation device and method, and more particularly, when transforming an object,
The present invention relates to a coordinate conversion device and method for performing coordinate conversion so that an object does not have an unnatural shape by performing scaling for each layer and then performing coordinate conversion to an upper layer.

[0002]

2. Description of the Related Art With the recent widespread use of computer graphics, for example, a computer displays a 3D (three-dimensional) object moving an arm or leg as shown in FIG. Is coming.

When displaying the movement of such an object, the movement of the partial object is calculated in the local coordinate system of the partial objects constituting the object, and the coordinates of the entire object are calculated from the local coordinate system of each partial object. After the coordinate conversion to the system is performed and the motion of the partial object in the local coordinate system is converted into the motion in the coordinate system of the entire object (global coordinate system), the entire object is displayed.

Further, the object has a hierarchical structure of partial objects, and the coordinate conversion from the local coordinate system of the partial object to the coordinate system of the whole object is
Coordinate conversion from the coordinate system of the partial object belonging to the lower hierarchy to the coordinate system of the partial object of the upper hierarchy is performed until reaching the coordinate system of the partial object of the highest hierarchy, and finally, the partial object of the highest hierarchy. It is realized by converting from the coordinate system of to the coordinate system of the entire object.

For example, the 3D object in FIG. 3A is composed of the partial objects of the head, body, arm 1, arm 2, leg 1 and leg 2 shown in FIG. 3B, and the head is at the top. In the hierarchy, the body is the second hierarchy from the top, and the arm 1, arm 2, leg 1 and leg 2 are the lowest hierarchy.

In this object, when the local coordinate system of the arm 1, the arm 2, the leg 1 and the leg 2 is converted to the global coordinate system, first, the arm 1, the arm 2, the leg 1 or the leg 2 is converted. The local coordinate system of is transformed to the local coordinate system of the body, and then the local coordinate system of the body is transformed to the local coordinate system of the head. Then, finally, conversion from the local coordinate system of the head to the global coordinate system is performed.

Further, when the transformation from the local coordinate system of the body to the global coordinate system is performed, first, the transformation from the local coordinate system of the body to the local coordinate system of the head is performed. Then, the conversion from the local coordinate system of the head to the global coordinate system is performed.

These local coordinate systems (represented by vectors) are coordinated by a predetermined coordinate transformation matrix (M _head , M _body, etc.) as shown in FIG. Converted to the system (global coordinate system).

For example, the transformation from the local coordinate system P _arm2 of the arm 2 to the global coordinate system _{P'is performed} by using the coordinate transformation matrix shown in FIG. P '= M _head , M _body , M _arm2 , P _arm2

In this coordinate transformation, first, the matrix M
The coordinates of the arm 2 are converted to the body coordinate system by _arm2 , and then to the head coordinate system by the matrix M _body . Then, finally, the local coordinates of the arm 2 converted into the coordinate system of the head are converted into the global coordinate system by the matrix M _head .

The coordinate conversion from the local coordinate system to the global coordinate system is performed as described above. When such an object is deformed and displayed, the object can be deformed by performing non-uniform scaling on the coordinates while converting the coordinates from the local coordinate system to the global coordinate system.

FIG. 4 shows an example of the configuration of a coordinate conversion device for performing coordinate conversion including such non-uniform scaling. This configuration example has a coordinate system rotation circuit 21, and the coordinate system rotation circuit 21 transforms the local coordinates of the arm 2 with a transformation matrix R to express the rotation of the arm 2.

When the local coordinates of the arm 2 accompanied by rotation are converted into global coordinates, first, the local coordinates of the arm 2 are input to the coordinate system rotation circuit 21, and the coordinate system rotation circuit 21 uses the rotation conversion matrix R. And the input coordinates (vector) are calculated,
The product (vector) of the coordinate conversion circuit 2 from the arm 2 to the body
-2.

Next, the coordinate conversion circuit 2-from the arm 2 to the body 2
2 calculates the product of the transformation matrix M _arm2 and the input coordinates (vector) of the arm 2 and outputs the product to the coordinate transformation circuit 3-2 from the body to the head as a local coordinate system in the body. The body-to-head coordinate conversion circuit 3-2 uses the conversion matrix M _body to convert the coordinates into coordinates in the local coordinate system of the head, and then
Output to the scaling circuit 6.

The scaling circuit 6 calculates the product of the coordinates (vector) and the non-uniform scaling matrix S, and converts the scaled coordinates (vector) from the head to the global coordinate system 4-2. Output to. The coordinate conversion circuit 4-2 from the head to the global coordinate system calculates the coordinates and the conversion matrix M.
Calculates the product (vector) of _head and outputs the product as coordinates in the global coordinate system. Therefore, the local coordinate system P of the arm 2 is
_{The conversion} from _arm2 to the global coordinate system _P'is as follows. P '= M _head , S, M _body , M _arm2 , R, P _arm2

When the local coordinates of the body are converted into global coordinates, the local coordinates of the body are converted from the body to the head by the coordinate conversion circuit 3.
-2, the scaling circuit 6, and the coordinate conversion circuit 4-2 from the head to the global coordinate system apply the matrices M _body , S, and M _head , respectively, and convert the coordinates into the coordinates in the global coordinate system. Therefore, the conversion from the local coordinate system P _{body of the body} to the global coordinate system P ′ is as follows. P '= M _head , S, M _body , P _body

Similarly, when the local coordinates of the head are converted into the global coordinates, the local coordinates of the head are calculated in the scaling circuit 6 and the coordinate conversion circuit 4-2 from the head to the global coordinate system, respectively, in the matrices S and M _head. Is applied to the coordinates in the global coordinate system, and the conversion from the head local coordinate system P _head to the global coordinate system P ′ is given by the following equation. P '= M _head , S, P _head

In this way, each local coordinate is converted into a coordinate in the global coordinate system as shown in the above equation, and is used for expressing the motion of the object.

[0019]

However, in the coordinate conversion from P _arm2 to P ′ according to the above conversion formula, the conversion matrix R regarding rotation is applied before the non-uniform scaling matrix S, so that the arm 2 Has the problem of being scaled after being rotated and transformed into an unnatural shape in the global coordinate system.

For example, when an object as shown in FIG. 5 (a) is vertically scaled by a factor of 2, if the arm is not rotated, the object is scaled as shown in FIG. 5 (b). When the arm is rotated, the arm is rotated before being scaled.
As shown in (c), the length unnaturally becomes double (in this case, as shown in FIG. 5D, it is preferable that the arm rotates with the same length).

The present invention has been made in view of such a situation, and after performing scaling considering rotation for each partial object such as an arm, the upper layer (for example, in the case of arm 2, the body is an upper layer). The object is prevented from being transformed into an unnatural shape by performing coordinate transformation to ().

[0022]

According to a first aspect of the present invention, there is provided an image conversion apparatus, wherein an arithmetic means for scaling local coordinates for each layer and a higher rank for each layer with respect to the scaled local coordinates. Coordinate conversion means for performing coordinate conversion into a hierarchy is provided.

In the image conversion method according to the second aspect, scaling is performed on the local coordinates for each layer, and the scaled local coordinates are converted to the upper layer for each layer. Characterize.

According to another aspect of the image conversion device of the present invention, the calculation means scales the local coordinates layer by layer, and the coordinate conversion means scales the scaled local coordinates layer by layer. Performs coordinate conversion to the upper layer.

In the image conversion method according to the second aspect, scaling is performed on the local coordinates for each layer,
With respect to the scaled local coordinates, coordinate conversion to an upper layer is performed for each layer.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the configuration of an embodiment of a coordinate conversion device of the present invention. This embodiment has three coordinate conversion circuits 2-1, 3-1 and 4-1 (coordinate conversion means).
And three scaling circuits 1, 5 and 6 (calculation means).

The coordinate conversion circuit 2-1 from the arm 2 to the body is
The local coordinates of the arm 2 that has been subjected to scaling and rotation processing by the matrix S _arm2 are supplied from the scaling circuit 1.
The coordinates are converted into coordinates in the local coordinate system of the body after scaling by the conversion matrix M _arm2 ″.

The body-to-head coordinate conversion circuit 3-1 is output from the scaling circuit 5 with the local coordinates of the body subjected to scaling processing by the matrix S _body , or from the arm 2 to body coordinate conversion circuit 2-1. The coordinates are supplied, and the coordinates are converted into the coordinates in the local coordinate system of the head after scaling by the conversion matrix M _body ″.

Coordinate conversion circuit 4-1 from head to global coordinate system
Is supplied from the scaling circuit 6 with the local coordinates of the head that has been subjected to scaling processing by the matrix S, or the coordinates output from the body-to-head coordinate conversion circuit 3-1. The coordinates are converted into global coordinates by the conversion matrix M _head. Convert to system coordinates.

The transformation from the local coordinate system P _ARM2 arm 2 to the global coordinate system P 'is, in the conventional method, M _head · S ·
It is expressed by M _body , M _arm2, and R, but in this embodiment, the coordinate conversion portion M _head
M _body "/ M _arm2 " and rotation and scaling part S
_It is separated into _arm2 and expressed by coordinate conversion as shown below. P '= M _head , M _body ", M _arm2 ", S _arm2 , P _arm2

Similarly, the transformation from the local coordinate system P _{body of the body} to the global coordinate system P'is also divided into the coordinate transformation part and the scaling part, and the coordinate transformation as in the following equation is performed. P '= M _head , M _body ", S _body , P _body

From the local coordinate system P _{head of the head} to the global coordinate system P '
Since the conversion to is conventionally separated, the conversion is performed as it is as in the following equation. P '= M _head , S, P _head

Incidentally, the coordinate conversion from the local coordinate system P _{body of the body} to the global coordinate system _P'is performed by M _head in the conventional method.
_-Although it is performed by S / M _body , in the present embodiment,
The coordinate conversion part M _body 'and the scaling part S _body are separated and performed as in the following equation. P '= M _body ', S _body , P _body

In the present embodiment, the scaling circuit 5
(S _body ), body-to-head coordinate conversion circuit 3-1 (M
_body "), and coordinate conversion circuit 4 from head to global coordinate system
Since the coordinate conversion from the local coordinate system of the body to the global coordinate system is performed by −1 (M _head ), M _body ′ · S _body in the above equation is
The coordinate transformation matrix M _body ″ (used in the body-to-head coordinate transformation circuit 3-1) which is equal to M _head · M _body ″ · S _body and which is the local coordinate system of the body to the local coordinate system of the head is It becomes like a formula. M _body ”= M _head ^-1 · M _body '

Further, the coordinate conversion from the local coordinate system P _arm2 of the arm 2 to the global coordinate system is conventionally performed by M _head , S, M _body , M.
_Although it is carried out by _arm2.R , in this embodiment, the coordinate conversion part M _arm2 'and the rotation and scaling part S _arm2.
Is performed and is performed as follows. P '= M _arm2 ', S _arm2 , P _arm2

In the present embodiment, the scaling circuit 1
(S _arm2 ), the coordinate conversion circuit 2-1 from the arm 2 to the body (M
_arm2 "), body-to-head coordinate transformation circuit 3-1
(M _body "), and the coordinate transformation circuit 4-1 to the global coordinate system (M _head) from head, since the coordinate transformation to the global coordinate system from the local coordinate system of the arm 2, in the formula M _ARM2 '・ S
_arm2 is _equal to M _head , M _body ", M _arm2 ", and S _arm2, and the coordinate conversion matrix M _arm2 "from the local coordinate system of the arm 2 to the local coordinate system of the body (the coordinate conversion circuit 2 from the arm 2 to the body 2 -1
Used in) becomes as follows. M _arm2 ”= M _body ” ^-1 , M _head ^-1 , M _arm2 '

As described above, the scaling matrices S, S
After scaling for each local coordinate system with _body and S _arm2 , transformation matrices M _head , M _body ″, and M _arm2 ″ are obtained.
Since local coordinates are converted into global coordinates, for example, arm 2
Even when is accompanied by rotation, scaling considering rotation is performed by the scaling circuit 1 to prevent unnatural deformation of the object, and natural deformation can be performed as shown in FIG. 5D. .

Next, referring to the flowchart of FIG.
The operation of the above embodiment will be described.

First, in step S1, it is determined whether or not the coordinates to be converted are in the head's local coordinate system. If not, the process proceeds to step S2.
It is determined whether the coordinates to be transformed are in the local coordinate system of the body.

If the coordinate to be converted is not in the local coordinate system of the body (that is, in the local coordinate system of the arm 2), the process proceeds to step S3, the local coordinate is input to the scaling circuit 1, and the scaling circuit 1 Is the scaling matrix S
_The arm 2 scales the input coordinates in consideration of the rotation, and then outputs the coordinates to the body-to-body coordinate conversion circuit 2-1.

Next, in step S4, the arm 2 to body coordinate conversion circuit 2-1 converts the local coordinates scaled by the matrix S _arm2 by the conversion matrix M _arm2 ″,
It outputs to the body-to-head coordinate conversion circuit 3-1.

Then, in step S5, the body-to-head coordinate conversion circuit 3-1 converts the coordinates input from the arm 2 to body coordinate conversion circuit 2-1 into a conversion matrix M _body ″.
And outputs the converted coordinates to the coordinate conversion circuit 4-1 from the head to the global coordinate system. Next, in step S6, the coordinate conversion circuit 4-1 from the head to the global coordinate system outputs M
_The coordinates converted by " _body " are further converted into a global coordinate system by M _head , and the converted coordinates are output.

If it is determined in step S2 that the coordinates to be converted are in the local coordinate system of the body, the process proceeds to step S7 and the coordinates are input to the scaling circuit 5. The scaling circuit 5 scales the coordinates with the scaling matrix S _body and then outputs the coordinates to the body-to-head coordinate conversion circuit 3-1.

Next, in step S5, the body-to-head coordinate conversion circuit 3-1 converts the local coordinates scaled by S _body by the conversion matrix M _body ″, and then moves from the head to the global coordinate system. Then, in step S6, the head-to-global coordinate system coordinate conversion circuit 4-1 outputs the coordinates converted by M _body ″ to the global coordinate system by M _head. Convert and output the converted coordinates as coordinates in the global coordinate system.

When it is determined in step S1 that the coordinate to be converted is in the head local coordinate system, the process proceeds to step S8, the local coordinate is input to the scaling circuit 6, and the scaling circuit 6 causes the scaling matrix S to be input. After converting the input coordinates, it outputs to the coordinate conversion circuit 4-1 from the head to the global coordinate system. And step S
6, the coordinate conversion circuit 4-1 from the head to the global coordinate system
Further converts the coordinates converted by M _body ″ into a global coordinate system by M _head , and outputs the converted coordinates as coordinates in the global coordinate system.

As described above, with respect to the coordinates of the head, body, and arm 2 in the local coordinate system, the scaling matrix S,
After scaling with S _body and S _arm2 ,
Coordinate conversion from the local coordinate system of the arm 2 to the global coordinate system is performed.
Therefore, even if the object shown in FIG. 5 (a) is enlarged in the vertical direction and its arm is rotated, it will not be as shown in FIG. 5 (c) but as shown in FIG. 5 (d).

In this embodiment, the local coordinates of the arm 2 are converted into global coordinates, but the local coordinates of the arm 1, leg 1, and leg 2 can be converted into global coordinates. You can also In that case, a scaling matrix can be prepared for each of the arm 1, the arm 2, the leg 1, and the leg 2 to express the rotation of each partial object.

[0048]

As described above, according to the coordinate conversion device and method of the present invention, in the coordinate conversion of an object having a hierarchical structure, scaling is performed for each layer and then the coordinate conversion to a higher layer is performed. By doing so, it is possible to prevent the object from being transformed into an unnatural shape due to scaling.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of an embodiment of a coordinate conversion device of the present invention.

FIG. 2 is a flowchart illustrating the operation of the embodiment of FIG.

FIG. 3 is a diagram showing an example of a hierarchical structure of objects for which coordinate conversion is performed.

FIG. 4 is a block diagram showing a configuration example of a conventional coordinate conversion device.

FIG. 5 is a diagram showing an example of a scaled object.

[Explanation of symbols]

 1 Scaling circuit 2-1 and 2-2 Coordinate conversion circuit from arm 2 to body 3-1 and 3-2 Coordinate conversion circuit from body to head 4-1 and 4-2 Coordinate conversion from head to global coordinate system Circuit 5,6 Scaling circuit 21 Coordinate system rotation circuit

Claims (2)

[Claims] 1. A coordinate transformation device for performing coordinate transformation from local coordinates of each layer to global coordinates in an object having a hierarchical structure, comprising: computing means for scaling the local coordinates for each layer; A coordinate conversion device, comprising: coordinate conversion means for converting the applied local coordinates into an upper layer for each layer. 2. A coordinate conversion method for performing coordinate conversion from local coordinates of each layer to global coordinates in an object having a hierarchical structure, wherein the local coordinates are scaled for each layer, and the scaling is performed. A coordinate conversion method, wherein local coordinates are converted to an upper layer for each layer.