JP3312337B2 - How to display computer graphics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for displaying a computer graphic in a motion expression method for moving an articulated object such as a human or an animal by the computer graphic, and more particularly, to setting an operation when changing the size of the articulated object. The present invention relates to a computer graphic display method which is easy to change and suitable for enabling abundant motion expression.

[0002]

2. Description of the Related Art In the case of expressing a human walking motion, a cantering motion, a motion of a horse or a measuring insect by computer graphics, a key frame method is generally used. In this key frame method, the shape of an articulated object such as a human or a horse to be moved is determined at one time and the shape at the next time, and the shape at the time between the two is determined by an interpolation method. By sequentially displaying each shape in a time series, it is expressed that the articulated object is moving as a whole. This key frame method has a problem that it takes time to determine each time-sequential shape that determines the movement of the operation target, and the processing time becomes enormous, thereby imposing a burden on the operator.

[0003] Conventionally, the IEICE Transactions '80
/ 1, Vol. As described in J63-DNo.1 page 87 “Triangle Function Approximate Expression Moving Image by Combining Animation Primitives”, human movement was photographed with 16 mm film to measure the movement of typical joints. The motion trajectory of each joint part is obtained based on how many cm from the reference position the horizontal and vertical positions X and Y of each joint part are as a function of time T. And the motion trajectory is expressed as a straight line and 3
An approximation is made using an angle function curve, and the computer calculates time-series shape data from the approximation curve and sequentially displays the data.

[0004]

The prior art described above is
Approximate curves are obtained using the movements of the joints obtained by photographing as changes in the X position and the Y position from the reference position at each time. For this reason, it is good to express the motion using this approximation curve, but it is not applicable to the case where the size of the motion target changes or the case where the motion is performed by changing the ratio of the size between the joints. There is a problem that the ratio has to be repeated from photographing again and the degree of freedom is small.
In other words, this conventional technique can move an articulated object on computer graphics only as an analogy of a photographed real object. This means that abundant operations cannot be performed on computer graphics. That is, for example, a captured standard walking motion can only be represented on a computer graphic, but it is not possible to express, for example, a “rough walking motion” or a “fun walking motion” by changing the standard motion. For this reason, conventionally, when it is desired to express such an operation, it is necessary to actually perform a “rough walking operation” or the like by a human, photograph the operation, and analyze the operation. In other words, an animal, an insect, or an imaginary object that cannot actually capture abundant motion expressions indicates that it is difficult to move in various motion modes using computer graphics.

A first object of the present invention is to provide a computer graphic display method capable of easily changing the operation of a computer graphic even when the size of an operation target or the dimensional ratio of each part is changed. It is in.

A second object of the present invention is to provide a computer graphic display method that makes it easy to cause an operation target to take various operation forms in computer graphic.

[0007] A third object of the present invention is that even when an actual robot is operated, the same problem as described above occurs.
It is an object of the present invention to provide a computer graphic display method capable of determining the operation of a robot without depending on the size of the robot and instructing various operations.

[0008]

The object of the present invention is to measure the motion of an articulated object by frequency analysis , obtain a function representing the bending angle of the joint based on the measured value, and obtain a function based on the periodic function.
This is achieved by displaying an image of the articulated object on a display screen . The above object is achieved in the above configuration, in which the frequency analysis is a Fourier analysis. The purpose is to measure the motion of an articulated object and use the measured
Find the frequency function that represents the bending angle of the node, and calculate its periodic function
Basically , this is achieved by displaying an image of the articulated object on a display screen . The above object is achieved in the first or third configuration, in which the image to be displayed is an image in which a joint of the articulated object is fleshed out .

[0009]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of a computer graphic device according to a first embodiment of the present invention. As shown in FIG. 2, the computer graphic device displays an image 1 of a human being, which is an example of an articulated object, on a display screen such as a CRT. In this example, human 1
As shown in FIG. 3, it is expressed as a multi-joint line drawing, and each joint of the line drawing (in the example of FIG. 3, 2 is a hip joint, 3 is a knee joint, 4 is an elbow joint, 5 is a shoulder joint) The joints are shown in various shapes by controlling the bending angle, and the line drawing is fleshed out as a human, thereby displaying a human motion image as shown in FIG.

The computer graphic device shown in FIG. 1 stores a basic operation function storage device 10 in which a periodic function representing a bending angle of each joint is stored for each basic operation, and a desired function from various functions in the storage device 10. A basic operation selection device 11 for selecting a function, and a storage device 10 selected by the device 11
The joint angle calculation device 12 reads the function read out from the CPU and calculates the bending angle of the corresponding joint in time series with the function, and controls the speed calculated in the time series in the calculation device 12, that is, the operation speed of the joint. Speed control device 13, an articulated object shape storage device 15 that stores shapes to fill in line drawings of various articulated objects, a shape selecting device 16 that selects the shape of the articulated object, and a calculation device 12. Rendering device 14 for generating image information for fleshing out the motion of the articulated object represented only by the joint bending angle in a shape read from the storage device 15 and displaying the image information in two dimensions, and a display device 17 for displaying the image information And comprising.

The basic motion function storage device 10 stores a function in which the motion of each joint is converted into a function for each basic motion such as "walking motion", "running motion", "sitting motion" and the like. Then, as shown in FIG. 2, the operator selects the basic operation by picking the basic operation designation icon 30 displayed on the display screen. Hereinafter, a function regarding the “walking motion” of a human will be described as an example.

FIG. 4 is a curve showing the time change of the measured value of the bending angle of the main joint when a walking person is viewed from the side (in the X-axis direction). 2a is a change curve of the hip joint, 3a is a change curve of the knee joint, 4a is a change curve of the elbow joint, and 5a is a change curve of the shoulder joint. This measured value is 2
Although the measurement is made for the cycle (two steps), it can be seen that there is a correlation between the movements between the joints. FIG. 5 shows the result of Fourier analysis of the measured knee joint value 3a shown in FIG. The main spectrum is at most several orders. Therefore, the time change Δm (t) of the bending angle of the joint can be represented by the following function of a very low order.

[0014]

(Equation 7) Here, Dm: DC component Amn: Amplitude of each frequency component Ψmn: Phase m: Joint number n: nth harmonic Φm: Phase difference between the first harmonic of the reference joint and mth joint (Φm in the reference joint) = 0.) Note that the harmony between the movements of the joints is determined by the phase difference Φm between the joints.
And this phase difference is preserved.

The joint angle calculation device 12 shown in FIG. 1 calculates the movement of the knee joint using this function (1) while changing the value of the variable t, and sequentially displays the position of the knee joint at each t. ,
The moving knee is displayed. The operation speed is shown in FIG.
The speed control device 13 in FIG. 1 is operated by moving the display of the vertical bar 40 in the operation specifying icon 33 shown in FIG. The function angle calculation device 12 uses the equation (1) to time-sequentially calculate Θm (t
1), Θm (t2), Θm (t3)... Are calculated. When the operator specifies a high operation speed, t2-t1 = t3-t
2 =... = Δt is calculated by increasing the value.

Since the function represented by the above equation (1) does not have a parameter indicating the length, it is not necessary to change the function even when the size or the dimensional ratio of the model changes. Therefore, even when the size of the model to be displayed is changed, the burden on the operator is reduced, and the operation display of the model after the change can be quickly performed. That is, in the present embodiment, the motion of the articulated object can be expressed with a very small amount of information and operation by simply selecting the type of the basic motion, the motion speed, and the shape of the articulated object.

FIG. 6 is a block diagram of a computer graphic device according to a second embodiment of the present invention. Compared with the first embodiment shown in FIG. 1, an adverb component storage device 20 and an adverb component selection device 21 are newly provided.
Performs an operation using the selected basic motion function and the selected adverb component. It corresponds to the adverb component and the “adverb” in the Japanese grammar, and modifies the action. In other words, "happy", "sad" or "fun". In the present embodiment, the adverb is converted into a function, and the operator specifies which adverb is to be selected. As shown in FIG. 2, in the present embodiment, the adverb selection icon 31 on the screen can be selected by picking it. For example, when the mouse cursor or the like is moved to the icon 31 and the left button is picked, “pleasantly”,
"Fun", "Drunk", "Otto", ... are displayed in order, and when the corresponding adverb appears, pick the right button to select it. When "walking motion" is selected as the basic motion and "fun" is selected as the adverb, the displayed human image 1 performs a "walking happily" motion. Hereinafter, the control of the adverb will be described.

FIG. 7A is a graph showing the time change of the actual measured value of the knee joint bending angle when "walking normally".
(B) is a graph which shows the time change of the measured value of the knee joint bending angle at the time of "walking happily". FIG. 8 shows the result of the spectrum analysis of the “walk happily” graph shown in FIG. 7B, and FIG. 5 shows the result of the spectrum analysis when “walking standard”. The difference between the two spectral analyzes is a "fun" component, which is shown in FIG. still,
FIGS. 5, 8, and 9 show only the power spectrum, and their phases are also different. According to FIG. 9, the "fun" main spectrum is at most several orders. The function Θm (t) indicating the knee bending angle in consideration of the adverb of “fun” is given by the following equation (2).

[0019]

(Equation 8) Here, dmn: DC component of “fun”. Amn: “fun” component of each frequency component. Ψmn: phase component of “fun”. The operator selected “fun” as an adverb using the selection device 21 (FIG. 6). In this case, the values of dm, amn, and ψmn are read out from the adverb component storage device 20, and these values are combined with the above (1) to be calculated by the arithmetic device 12 as Expression (2). As a result, an image of a person who "walks happily" is displayed on the screen.

In this embodiment, it is possible to cause the articulated object to perform the operation modified by the adverb simply by adding the adverb selection operation to the operation of the first embodiment.

FIG. 10 is a block diagram of a computer graphic device according to a third embodiment of the present invention. In the present embodiment, as compared with the configuration of the second embodiment of FIG.
2 and an adverb weight instruction indicating device 23 are added. In the present embodiment, as a function expression calculated by the joint angle calculation device 12,
The following equation (3) is used.

[0022]

(Equation 9) In this equation, αm is the weight of the adverb and βm is the weight of the amplitude. By changing the adverb weight αm, it is possible to specify from “standard walking” to “fun walking” to “very fun walking”. Alternatively, the adverb “sadly”, which is the opposite of “fun”, may be specified from “very sad” to “standard” to “very fun”. The designation by the adverb weight indicating device 23 is performed by moving the display of the vertical bar 40 of the icon 34 for designating the strength of the adverb in FIG. The amplitude weight βm corresponds to the step length, and is represented by the vertical bar 4 of the icon 32 in FIG.
The larger the value of 0 is to the right, the larger the value is. In other words, walk with a large stride.

According to the present embodiment, the degree of the adverb and the stride can be changed only by adding the weight designation operation to the operation of the second embodiment, and the change can be performed continuously. Becomes possible.

FIG. 11 is a block diagram of a computer graphic apparatus according to a fourth embodiment of the present invention. In the third embodiment, only one type of adverb can be designated. However, in this embodiment, an adverb control device 24 and an adverb weight indicating device 25 capable of designating a plurality of adverbs are used. According to this embodiment, for example, a “walking action” of “fun” and “slow” can be performed. The function expression in this case is
It is expressed by the following equation (4). In the equation (4), the weight of each parameter can be changed.

[0025]

(Equation 10) By adopting a configuration in which a plurality of adverbs can be specified in this manner, a wider variety of motion expressions can be achieved.

As described above, according to this embodiment, it is possible to continuously change the parameters of the function formula, and furthermore, it is possible to interactively and in real time change the human motion expression by the changed parameters. It is.

Although the above-described embodiment is an operation display in computer graphics, if the operation result of the function angle calculation device is used as an operation command to be an operation control signal of a real articulated robot, it depends on the size of the robot. It is possible to make a robot control device that does not use it, and to make the robot perform abundant operations represented by adverbs. Also book
The invention is not limited to the above-described embodiment.
When the bending angle of each joint of the object is expressed by a function, the length between joints
And can be expressed independently. Therefore, to display
When calculating the shape of a knotted object using the bending angle of the joint,
Independent of the size of the model, that is, without recreating the function
Can be calculated. For this reason, the size of the model
Even if a change occurs, use the function already set
It is possible to calculate. Also, the parameters of this function
Change the bending angle change speed at each joint
By doing so, it is possible to change the motion expression.

[0028]

According to the present invention, a shape during operation is calculated using a function formula independent of the size of a model or a robot, so that models or robots of various sizes can be moved in real time. Become. In addition, since the action modified by the adverb can be performed and the degree expressed by the adverb can be changed, abundant actions can be expressed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a computer graphic device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a display screen of the computer graphic device.

FIG. 3 is a diagram showing a human as a line drawing.

FIG. 4 is a graph showing actually measured values of changes in bending angles of main human joints.

FIG. 5 is a spectrum diagram of a curve 3a in FIG. 4;

FIG. 6 is a configuration diagram of a computer graphic device according to a second embodiment of the present invention.

7 is a graph showing a change in bending angle, and FIG. 7A is a graph showing a change in bending angle of a knee joint in a standard walking motion, which is the same as the curve 3a in FIG. 4, and FIG. b)
Is a graph showing a change in the bending angle of the knee joint when "walking happily".

FIG. 8 is a spectrum diagram of FIG. 7 (b).

FIG. 9 is a spectrum diagram showing a spectrum difference between FIGS. 5 and 8;

FIG. 10 is a configuration diagram of a computer graphic device according to a third embodiment of the present invention.

FIG. 11 is a configuration diagram of a computer graphic device according to a fourth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Basic motion function storage device, 11 ... Basic motion selection device, 12 ... Joint angle calculation device, 13 ... Speed control device, 14
... Rendering device, 17 ... Display device, 20 ... Adverb component storage device, 21 ... Adverb component selection device, 22, 24 ... Adverb control device, 23,25 ... Adverb weight indicating device.

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-1-26274 (JP, A) Seiki Inoue, Kenji Kira, Hiromichi Izawa, Development of Flexible Walking Model and Character Animation Production Method, Television Society Technical Report, The Institute of Television Engineers of Japan, Vol. 8, No. 25, p. 13-18 (58) Fields investigated (Int. Cl. ⁷ , DB name) G06T 1/00 G06T 11/60-17/50 G06F 17/50 G05B 19/18-19/46 JICST file (JOIS)

Claims (4)

(57) [Claims] 1. A motion of an articulated object is measured by frequency analysis , a function representing a bending angle of a joint is obtained based on the measured value, and an image of the articulated object is obtained based on the periodic function. Displaying a computer graphic on a display screen. 2. The method according to claim 1, wherein the frequency analysis includes:
A computer graphic display method characterized by Fourier analysis . 3. A method for measuring the movement of an articulated object, and measuring the measured value.
Frequency function representing the bending angle of the joint based on
Display the image of the articulated object on the display screen based on the period function
Display method of computer graphics, characterized in that that. 4. The display according to claim 1, wherein the display is performed.
The image is an image in which the joints of the articulated object are fleshed out
A method for displaying computer graphics, the method comprising: