KR20100044549A - A method and apparatus for expressing the variation of volume in human skin for the computer graphic animation - Google Patents

Abstract

PURPOSE: A method and an apparatus for expressing the variation of volume in a human skin for computer graphic animation are provided to express the volume variation of a human skin near a corresponding muscle by using an electromyography signal. CONSTITUTION: A method for expressing the variation of volume in a human skin for computer graphic animation comprises the steps of: obtaining electromyography data; performing a pretreatment procedure that passes through a notch filter and a bandpass filter; extracting an enveloper from the electromyography data; judging whether to measure an MVC(Maximal Voluntary Contraction); extracting the MVC value from the amplified electromyography signal from which noises are removed; judging the motion of a muscle in case the measured MVC value exits and there is not motion of a character and expressing the variation of the skin; expressing the motion of the character if the amplitude of the electromyography signal is similar to the MVC and there is movement of the character.

Description

FIELD AND APPARATUS FOR EXPRESSING THE VARIATION OF VOLUME IN HUMAN SKIN FOR THE COMPUTER GRAPHIC ANIMATION

The present invention relates to two-dimensional and three-dimensional graphics and animation, and in particular, it is possible to precisely express changes in skin volume of actors by using EMG signals capable of capturing camera and muscle movements used in computer graphics animation production. A method and apparatus for expressing volume change of human skin for computer graphics animation.

In the conventional game or animation field, although human movement is caused by muscle contraction and relaxation, it does not express skin changes caused by muscle movement. There was a problem that the reality is less by showing only movement.

On the other hand, EMG signal is one of the biological signals that can be measured when a particular muscle contracts, there is an advantage that can be easily measured without harming the user. Currently, many techniques for accurately measuring EMG, virtual reality technology applying EMG signal, control technology of arm prosthesis using EMG signal, computer interface device for hand disabled person, electric wheelchair interface method, EMG Facial muscle and eye movement tracking systems using electric eye diagram are disclosed in Korean Patent Laid-Open Publication Nos. 1999-0016950, 2008-0063904, 1989-016950, 1999-066563, 1999-066564, and 2002-077346. No. 2004-0069050, 2007-0057997.

However, the technique of visualizing the change of the skin according to the human motion using the EMG signal has not been proposed yet.

In the conventional animation field, the volume change of the skin according to the movement of the main joint is reduced when the joint is folded when the volume of the skin is 1 when the joint is extended. The volume change of the skin according to the movement of the human body was expressed by increasing the height in order to compensate this to the state of 1 volume.

However, there is no change in the behavior of the joint, such as isometric, but when the muscle is activated to maintain the state, a change in volume cannot be expressed by the conventional method.

The present invention has been invented in view of the above points, using motion capture equipment to determine whether or not the behavior of the joint, and using the EMG signal to express the volume change of the skin around the muscle similarly to the fact. It is an object of the present invention to provide a method and apparatus for expressing volume change of human skin for computer graphic animation.

According to an aspect of the present invention, there is provided a method of expressing a volume change of human skin for computer graphics animation, the method comprising: obtaining EMG data from an apical muscle of an actor (step 1); Performing a preprocessing process through a notch filter and a bandpass filter to remove noise from the acquired EMG data (step 2); Extracting an envelope from the EMG data in which the preprocessing process is performed (step 3); Determining whether MVC is to be measured to detect the magnitude of the EMG occurring at the maximum load after the envelope extraction is performed from the EMG data (step 4); Extracting the MVC value directly from the EMG signal from which the amplification and the noise have been removed if the MVC value measured in step 4 does not exist (step 5); In the case where the MVC value measured in step 4 already exists, it is determined whether there is a movement of the person, and if it is determined that there is no movement of the person, the movement of the muscle is determined, and then the skin change of the character is performed according to the existing method. Expressing (steps 6 to 8); If it is determined in step 6 that there is a movement of the person, it is determined whether the magnitude of the EMG signal is similar to the MVC, and if it is determined that the magnitude of the EMG signal is not similar to the MVC, Expressing the movement of the character (steps 9 to 10); In step 6, if it is determined that the magnitude of the EMG signal is similar to that of MVC, expressing the character's movement, determining the muscle's movement again, and expressing the character's skin change again based on this determination ( Step 9, step 11, step 7, step 8) is characterized in that made up.

In addition, the volume change expression apparatus of the human skin for computer graphics animation according to the present invention, attached to the main muscles of the actor detects EMG according to the movement of the main muscles of the actor, EMG sensor for generating an EMG signal based on the detected EMG (1); An EMG (2) receiving an EMG signal from the EMG sensor (1) to perform amplification and noise removal of the EMG signal; A signal processor (3) for extracting envelope extraction and maximum isometric contraction (MVC) value from the EMG signal from which the amplification and noise are removed from the EMG (2); A motion capture unit 4 for capturing motion associated with the movement of each segment of the body of the actor; Segmented motion signal generator (5) for generating segmented motion signals corresponding to the movement of each segment to represent the same movement as performed by an actor based on the motion capture data acquired by the motion capturer (4) And; Expression of the skin volume of the character is applied by applying the EMG signal from which the envelope extraction and the MVC value are extracted from the signal processor 3 and the segment motion signal corresponding to the movement of each segment of the human body from the signal generator 5. It is characterized in that it is provided with a skin volume change expression programming unit (6) for programming to express a change in the skin volume of the character.

According to the present invention, the motion capture equipment can be used to determine whether the corresponding joint is behaving, and the EMG signal can be used to express the volume change of the skin around the muscle similarly to the fact.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a system for implementing a method of expressing volume change of human skin according to an embodiment of the present invention.

In the animation field, there is a problem in that the skin change due to the contraction / relaxation of the muscle cannot be expressed when the character moves. For example, a weightlifter holding a barbell will cause many muscles to contract / relax as compared to the case where a barbell is not holding a barbell, thereby causing the skin to swell. In order to represent this case closely, the EMG and motion capture equipment can be used to measure muscle movement. Through this, the movement of the actor can be detected and the volume change of the skin can be expressed close to the real person according to the state of the muscle.

In Fig. 1, the EMG sensor 1 is attached to the main sinus muscle which generates a representative movement of a person, and detects the EMG according to the movement of the actor's main muscle muscle, and generates an EMG signal based on the detected EMG.

The EMG signal generated from the EMG sensor 1 is applied to the EMG 2, and the EMG 2 performs amplification and noise removal of the applied EMG signal. That is, a preprocessing process is performed through a notch filter and a bandpass filter to remove noise from the EMG signal (EMG data).

The EMG signal from which the amplification and noise have been removed from the EMG (2) is applied to the signal processing unit (3), and the signal processing unit (3) includes envelope extraction and maximum isotropic contraction (MVC) in the EMG signal from which the amplification and noise have been removed. Extract the value of Contraction and use it to express skin volume change. Here, a method of extracting an envelope from pre-processed EMG data includes moving average of full-wave rectified or half-wave rectified signals of the EMG signal and passing the low-pass filter on the rectified EMG signals.

Meanwhile, the motion capture unit 4 including various kinds of motion capture equipment (eg, mechanical, magnetic, and optical motion capture equipment) captures motion related to the movement of each segment of the actor's body, and thus captures the motion capture. The obtained signal is applied to the segment motion signal generator 5 to generate signals corresponding to the movement of each segment of the human body through motion capture to control the animated character. That is, segment motion signals corresponding to the motion of each segment are generated to represent the same motion as performed by the actor.

The EMG signal from which the envelope extraction and the MVC value are extracted from the signal processor 3 and the segment motion signal corresponding to the movement of each segment of the human body from the signal generator 5 express the change in the skin volume of the character. It is applied to the skin volume change expression programming unit 6, which is programmed to express the skin volume change of the character in the computer graphic animation.

FIG. 2 is a diagram illustrating an example of a human action and an EMG signal generated according to the biceps movement of the arm.

For example, in the case of the arm, as shown at the top of FIG. 2, when the arm is fully extended, that is, when there is no muscle movement, no EMG signal is generated as shown at the bottom of FIG. 2, but the arm is bent. In operation, EMG signals begin to occur. The maximum EMG signal is generated in a fully bent state, and when the arm starts to be extended again, the EMG signal decreases in size and disappears completely.

However, the EMG signal is a signal generated by the movement of the muscle, and there is a case in which the muscle is activated although there is no human movement, such as lifting a heavy object without bending or extending the arm. Therefore, motion capture equipment should be used to clearly express skin changes according to human movement.

FIG. 3 is a flowchart for describing a method of expressing a skin change of a character using an electromyography (EMG) signal and a motion capture device according to an embodiment of the present invention.

First, EMG data is acquired from the EMG sensor 1 attached to the dorsal root muscle of the actor (step 1).

The EMG (2) receiving the acquired EMG data performs a preprocessing process through a notch filter and a bandpass filter to remove noise from the acquired EMG data (step 2).

The EMG data obtained by the preprocessing process extracts an envelope from the signal processor 3 (step 3).

Subsequently, after envelope extraction is performed from EMG data, it is determined whether MVC is measured to detect the magnitude of EMG occurring at the maximum load (step 4).

If there is no MVC value already measured in step 4, the MVC value is extracted directly from the amplified and noise-free EMG signal (step 5), and the process returns to step 1.

If the MVC value measured in step 4 already exists, the process proceeds to step 6 to determine whether there is a movement of the person.

When it is determined in step 6 that there is no movement of the person, the movement of the muscle is determined (step 7), and then the skin change of the character is expressed according to the existing method (step 8). That is, when it is determined that there is no movement of the person, the movement of the character is not expressed, but since the EMG signal is generated, the movement of the muscle is judged to express the volume change of the skin where the muscle is located.

On the other hand, if it is determined in step 6 that there is a movement of the person, that is, if the movement of the person is detected through the motion capture unit 4 which is a motion capture device, the process proceeds to step 9 where the magnitude of the EMG signal at that time is MVC. Determine if the size is similar to.

If it is determined in step 9 that the magnitude of the EMG signal is not similar to that of MVC, the process proceeds to step 10 to express the movement of the character according to the conventional method.

On the other hand, if it is determined in step 9 that the magnitude of the EMG signal is similar to MVC, the process proceeds to step 11 because not only the movement of the character is expressed but also the muscles move excessively than normal, and the process proceeds to step 7. Then, the movement of the muscle is judged again, and the skin change of the character is expressed again in step 8 based on the judgment.

4 is a view showing an example of the volume change of the skin when there is no movement of the human body and an EMG signal is generated according to an embodiment of the present invention.

Although there is no movement of the actor, when the EMG signal is generated as shown in FIG. 4, it is determined that the muscle is moved according to the magnitude of the EMG signal, thereby expressing the volume change of the skin where the muscle is located.

5 is a photograph of an actor to which the optical marker and the EMG sensor are attached to the lower extremity of the human body, and shows the actual appearance of the EMG and the marker of the optical motion capture device.

Although the technical idea of the present invention has been described with reference to the drawings, this is by way of example to illustrate the most preferred embodiment of the present invention, it does not limit the present invention. In addition, it is obvious that any person skilled in the art may make various modifications and imitations without departing from the scope of the technical idea of the present invention.

1 is a block diagram of a system for implementing a method of expressing volume change of human skin according to an embodiment of the present invention;

2 is a diagram showing an example of an action and an EMG signal of a human body caused by the movement of the biceps of the arm;

3 is a flowchart for explaining a method of expressing a skin change of a character using an electromyography (EMG) signal and a motion capture device, according to an embodiment of the present invention;

4 is a view showing an example of the volume change of the skin when there is no movement of the human body and an EMG signal is generated according to an embodiment of the present invention,

5 is a photograph of an actor with an optical marker and an EMG sensor attached to the lower extremity of the human body.

Claims (2)

Acquiring EMG data from the dorsal root muscle (step 1); Performing a preprocessing process through a notch filter and a bandpass filter to remove noise from the acquired EMG data (step 2); Extracting an envelope from the EMG data in which the preprocessing process is performed (step 3); Determining whether MVC is to be measured to detect the magnitude of the EMG occurring at the maximum load after the envelope extraction is performed from the EMG data (step 4); Extracting the MVC value directly from the EMG signal from which the amplification and the noise have been removed if the MVC value measured in step 4 does not exist (step 5); In the case where the MVC value measured in step 4 already exists, it is determined whether there is a movement of the person, and if it is determined that there is no movement of the person, the movement of the muscle is determined, and then the skin change of the character is performed according to the existing method. Expressing (steps 6 to 8); If it is determined in step 6 that there is a movement of the person, it is determined whether the magnitude of the EMG signal is similar to the MVC, and if it is determined that the magnitude of the EMG signal is not similar to the MVC, Expressing the movement of the character (steps 9 to 10); In step 6, if it is determined that the magnitude of the EMG signal is similar to that of MVC, expressing the character's movement, determining the muscle's movement again, and expressing the character's skin change again based on this determination ( Step 9, Step 11, Step 7, Step 8) characterized in that the volume change representation method of the human skin for computer graphics animation. An EMG sensor (1) attached to the main root muscle of the actor to detect the EMG according to the movement of the main root muscle of the actor and generate an EMG signal based on the detected EMG; An EMG (2) receiving an EMG signal from the EMG sensor (1) to perform amplification and noise removal of the EMG signal; A signal processor (3) for extracting envelope extraction and maximum isometric contraction (MVC) value from the EMG signal from which the amplification and noise are removed from the EMG (2); A motion capture unit 4 for capturing motion associated with the movement of each segment of the body of the actor; Segmented motion signal generator (5) for generating segmented motion signals corresponding to the movement of each segment to represent the same movement as performed by an actor based on the motion capture data acquired by the motion capturer (4) And; Expression of the skin volume of the character is applied by applying the EMG signal from which the envelope extraction and the MVC value are extracted from the signal processor 3 and the segment motion signal corresponding to the movement of each segment of the human body from the signal generator 5. A volume change expression apparatus of human skin for computer graphics animation, comprising: a skin volume change expression programming unit (6) for programming to express a change in skin volume of a character.

Images