KR102293430B1 - Apparatus for function of vestibulo-ocular reflex based on virtual reality and multiple bio-sensor - Google Patents

Abstract

The present invention relates to an apparatus for evaluating vestibular-ocular reflex functions based on virtual reality and multiple biosignal sensors, comprising: a swivel chair that supports sitting and rotation of a subject; a head-wearable display device that is worn on the subject's head and covers the entire subject's eyes; Eye tracker (eye tracker) for sensing the eye rotation of the subject; Head movement sensor (IMU sensor) for sensing the head rotation of the subject; And after generating an examination screen for providing a dark field and playing it through the head-wearable display device, calculate and quantify the ratio of eye rotation to head rotation from the sensing results of the eye tracker and the head motion sensor to calculate and quantify the VOR (Vestibulo- and a control device for calculating and providing at least one of an Ocular Reflex) gain and an asymmetry ratio.

Description

Apparatus for function of vestibulo-ocular reflex based on virtual reality and multiple bio-sensor}

The present invention relates to an apparatus for evaluating vestibular-ocular reflex functions, which is based on virtual reality and biosignal sensors that can secure portability through minimal equipment, simplify measurement methods, and maximize test efficiency and accuracy. It relates to an apparatus for evaluating vestibular-ocular reflex function.

The lateral semicircular canal, located in the inner ear on both sides, is the most important for maintaining human balance among the vestibular organs and causes severe dizziness when damaged.

Tests that measure the function of the lateral semicircular canal include the bithermal caloric test, the rotation test, and the video head impulse test. Considering that, the most physiological test is the swivel chair test.

As shown in FIG. 1, the conventional rotating chair inspection equipment requires a separate dark room 11, and thus has a very large size. It typically occupies the largest space in a hospital vestibular laboratory and is an expensive piece of equipment.

Conventional swivel chair inspection equipment uses a servo motor 13 to induce head rotation. However, considering the size of the equipment, the motor performance is insufficient to accelerate and decelerate an adult at a predetermined acceleration. It is impossible to test in the 1-4 Hz band, which is the physiological range of head rotation frequencies used in life. Accordingly, the range of 0.01-0.64 Hz is mainly examined, but this is a state in which the head rotates very slowly, and the frequency of experience in daily life is low.

Conventional swivel chair test equipment rotates like a railroad stripe with light-dark repetitions in order to analyze the effects of visual-vestibular interaction (VVOR) and visual fixation (VFX). using a light (VVOR) or a laser that is attached to the swivel chair 12 and rotates according to the chair rotation. However, since only visual stimulation with a fixed rotational angular velocity is possible, a wide range of visual-vesicle interactions and visual fixation effects cannot be seen, and the strength of the visual stimulus is weak.

The reason for installing a large round screen or an outer wall in the conventional swivel chair examination equipment is that when there is a visual gaze point during the examination, the physiological action of the human body to visually gaze at a specific point is dominant, and the This is because eye rotation is strongly inhibited (in the case of the swivel chair test, approximately 80% or more is inhibited). As a result, especially when the head rotation speed during the examination is less than 50 ㅀ/sec, it is necessary to maintain a dark field in order to conduct the examination.

In addition, the conventional swivel chair inspection equipment self-manufactured a very heavy swivel chair 12 as shown in FIG. 1 to rotate at a predetermined frequency. For this reason, it is accompanied by a problem of frequent breakdowns and very high cost when moving and installing the equipment once installed.

The basic vestibular function to be measured through the conventional swivel chair examination equipment is the vestibulo-ocular reflex (VOR) function, which means a physiological reflex that induces eye rotation in the opposite direction to the rotation of the head. .

Through the vestibular-ocular reflex function, animals, including humans, can continuously gaze at a specific point or object regardless of head rotation. , as the head rotates, the eyeball cannot rotate in the opposite direction.

However, the conventional swivel chair test equipment has a limitation in that the test results of the most physiologically important frequency band cannot be obtained, and the test method is fixed, so that the information that can be obtained from the test is limited.

Domestic Patent Publication 10-2016-0005519 (published on January 15, 2016)

Accordingly, in order to solve the above problems, the present invention is to measure the vestibular-ocular reflex function of the subject at any time and anywhere by applying a technology completely different from existing equipment such as a head worn display device, an eye tracker, and a head motion sensor. It is intended to provide a virtual reality-based vestibular-ocular reflex function evaluation device that can maximize the efficiency and physiological compatibility of measurement motions.

The object of the present invention is not limited to the object mentioned above, and other objects not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description.

As a means for solving the above problems, according to an embodiment of the present invention, a swivel chair that supports the seating and rotation of the subject; a head-wearable display device that is worn on the subject's head and covers the entire subject's eyes; Eye tracker (eye tracker) for sensing the eye rotation of the subject; Head movement sensor (IMU sensor) for sensing the head rotation of the subject; And after generating an examination screen for providing a dark field and playing it through the head-wearable display device, calculate and quantify the ratio of eye rotation to head rotation from the sensing results of the eye tracker and the head motion sensor to calculate and quantify the VOR (Vestibulo- Provided is an apparatus for evaluating vestibular-ocular reflex functions based on virtual reality and biosignal sensors including a control device for calculating and providing at least one of ocular reflex) gain and asymmetry ratio.

The control device generates and reproduces a test screen for inducing preset head rotation and eye rotation, and then calculates and quantifies a head rotation to eyeball rotation ratio from the sensing results of the eye tracker and the head motion sensor to calculate and quantify the VOR (Vestibulo- Ocular Reflex) It is characterized in that it further comprises a function of calculating and providing at least one of a gain and an asymmetry ratio.

In addition, the control device configures and provides an examination screen for inducing preset head rotation and eye rotation, and it is characterized in that it is possible to adjust the ratio of the eye rotation to the head rotation, and the rotation angle and speed of the head and the eyeball in multiple stages.

In addition, the control device calculates a rotation angle-based gain from the eyeball rotation angle versus the head rotation angle, calculates a maximum rotational angular velocity-based gain from the maximum eyeball rotation angular velocity versus the maximum head rotation angular velocity, and calculates the maximum eye rotation angular acceleration versus the maximum head rotation angular acceleration After calculating the maximum rotational angular acceleration-based gain from , at least one of the rotational angle-based gain, the maximum rotational angular velocity-based gain, and the maximum rotational angular acceleration-based gain is selected and provided as the vestibular-ocular reflection gain.

"의 식에 따라 상기 비대칭 비율을 산출하며, 상기 회전 정도는 회전 각도, 회전 각속도, 회전 각가속도 중 어느 하나 인 것을 특징으로 한다. In addition, the control device

The asymmetry ratio is calculated according to the equation ", and the degree of rotation is any one of a rotation angle, a rotation angular velocity, and a rotation angular acceleration.

Finally, when the head rotation does not come within a preset target frequency, the control device requests a retry of the head rotation and then performs the vestibular-ocular reflex function evaluation operation once again. Virtual reality and biosignal sensor Based vestibular-ocular reflex function evaluation device.

The swivel chair is characterized in that it is automatically rotated under the control of the control device, or is manually rotated by a subject or an inspector.

The present invention provides information for measuring vestibular-ocular reflex function to a subject in a virtual reality method through a head-worn display device, and allows the subject's reaction to be measured through an eye tracker and a head motion sensor. In other words, by utilizing a new platform compared to existing equipment such as a head-worn display device, eye tracker, and head movement sensor, the subject's vestibular-ocular reflex function is measured through simple movements such as active rotation of the subject and hand rotation of the examinee. , simplifying the inspection and ensuring the portability of the device.

In addition, by providing the subject with a variety of visual stimulus information linked to the rotation of the head through the head mounted display device, the visual-vestibular interaction of the subject can be measured in more detail and accurately. In addition, the interaction between vision and vestibular-eye reflex is precisely evaluated by adjusting the ratio of eye rotation to head rotation in multiple stages, which could not be realized with existing equipment.

1 is a view showing a rotating chair inspection equipment according to the prior art.
2 is a diagram for explaining a phenomenon caused by an abnormality in vestibular function.
3 is a diagram illustrating a virtual reality-based vestibular-eye reflex function evaluation apparatus according to an embodiment of the present invention.
4 and 5 are diagrams for explaining a vestibular-ocular reflex function evaluation method according to an embodiment of the present invention.

Objects and effects of the present invention, and technical configurations for achieving them will become clear with reference to the embodiments described below in detail in conjunction with the accompanying drawings. In describing the present invention, if it is determined that a detailed description of a well-known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

And the terms to be described later are terms defined in consideration of functions in the present invention, which may vary depending on the intention or custom of the examinee and the operator.

However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. Only the present embodiments are provided so that the disclosure of the present invention is complete, and to fully inform those of ordinary skill in the art to which the present invention belongs, the scope of the invention, the present invention is defined by the scope of the claims will only be Therefore, the definition should be made based on the content throughout this specification.

3 is a diagram illustrating a virtual reality-based vestibular-eye reflex function evaluation apparatus according to an embodiment of the present invention.

3, the vestibular-ocular reflex function evaluation apparatus 100 of the present invention includes a rotating chair 110, a head-wearable display device 120, an eye tracker 130, a head motion sensor ( 140), and a control device 150, and the like.

The swivel chair 110 is a device that supports the seating and rotation of the subject, and may be implemented as any rotatable general chair. That is, the present invention can utilize a ready-made chair instead of the conventional self-made chair.

In addition, the rotating chair 110 rotates the examinee's head manually to induce the subject's head to rotate (manual rotation), or the subject rotates his/her head according to a guide displayed on the screen through the head wearable display device 120 . Active rotation is possible. Of course, if necessary, the seat plate and the backrest may be automatically rotated at a preset rotation angle and speed based on the motor under the control of the control device 150 .

The head mounted display device 120 may be implemented as a head mounted display (HMD) that is worn on a subject's head and covers the entire eye. This allows the test screen provided by the control device 150 to be reproduced in a virtual reality method, thereby providing an immersive feeling to the subject as if they were present in the virtual reality world.

In particular, the head-wearable display device 120 is preferably worn close to the eyes, in order to maintain a dark field for examination instead of the screen or outer wall of the conventional swivel chair examination equipment.

The eye tracker 130 senses the eye rotation of the subject. In this case, the eyeball rotation may be an eyeball rotation angle, an eyeball rotation speed, an eye closed, a pupil size, or the like.

The head motion sensor 140 is implemented as an inertial measurement unit sensor (IMU sensor) or a motion capture sensor coupled to the head wearable display device 120 to sense the head rotation of the subject. do. In this case, the head rotation may be a head rotation angle, a head rotation speed, or the like.

That is, the present invention is not a method of making a preset rotation pattern through a conventional self-made chair, but by measuring the rotation pattern through the head motion sensor 140, utilizing all of the general rotation chair vestibular-ocular reflex function Evaluate action can be performed. As a result, it is possible to secure portability and simplify the inspection method by minimizing the device volume and implementation cost.

The control device 150 generates an examination screen that induces a visual stimulus (eye rotation) in association with the head rotation and reproduces it through the head wearable display device 120 . And at the same time, based on the sensing results of the eye tracker 130 and the head motion sensor 140, calculate and quantify the head-to-eye rotation ratio to obtain vestibular-eye reflex gain and asymmetry ratio, visual-vesicular interaction, and fixation effect. to obtain and provide.

That is, the present invention is equipped with equipment for measuring head rotation, such as an inertial measurement sensor (IMU sensor) or a motion capture sensor, and equipment for evaluating eye rotation, such as an eye tracker, and this By temporally integrating and analyzing the information obtained from the two devices, it is possible to check whether the proper vestibular-ocular reflex occurs in response to the head rotation stimulus, and whether the eye movement in the opposite direction occurs at an appropriate angle, angular velocity, and angular acceleration in real time.

4 is a view for explaining a vestibular-ocular reflex function evaluation method according to an embodiment of the present invention.

First, an examination mode is determined at the request of the examinee or the examiner (S1), an examination screen corresponding to the examination mode is configured, and then it is reproduced in a virtual reality method through the head worn display device 120 (S2).

The test mode of the present invention may be divided into a basic vestibulo-ocular reflex (VOR) test mode, a visual vestibulo-ocular reflex (VVOR) test mode, and a visual fixation effect test mode (VFX).

And in the basic vestibular-ocular reflex (VOR) test mode, the virtual reality screen is basically darkened, and a screen that does not display any gaze points that can fix the gaze is configured to enable pure vestibular-ocular reflex measurement. That is, it configures and provides an examination screen for providing a dark field, and enables the vestibular-ocular reflex measurement in the corresponding state.

And in the visual-vestibular interaction test mode (VVOR), as in FIGS. 5 (a) and 5 (b), which show the situation in the real world under the virtual reality screen, the eye rotation versus the head rotation is adjusted at various ratios. By constructing and providing an examination screen that enables the test, the subject generates an amplified eye rotation compared to the head rotation. In particular, in addition to setting the degree of head rotation and the degree of eye rotation to be the same as shown in (a) of FIG. 5, it is possible to increase the degree of eye rotation compared to the degree of head rotation as shown in FIG. This corresponds to the Augmentation visual-vestibular interaction test mode. In the real world, for example, it is possible to evaluate the ability to stably gaze at a car moving in the same direction as the head rotation. do.

Finally, in the visual fixation effect inspection mode (VFX), the visual target rotates at the same angular velocity as the head rotation in the existing inspection, and as shown in FIG. A test screen is configured and provided so that the eyeball rotation can be suppressed compared to the head rotation, so that the examinee generates the suppressed eyeball rotation compared to the head rotation. This is the Suppression visual-vestibular interaction test mode, which allows us to evaluate the ability to stably gaze at a car moving in the direction opposite to head rotation, for example in the real world. .

Through step S1, the examination screen is reproduced in a virtual reality method, and when the subject moves the eyeball and head in response to this, the eyeball and head rotation are immediately measured using the eye tracker 130 and the head movement sensor 140. (S2,S3).

After the head rotation data is subjected to the measurement noise removal process, precise estimates of the rotation amount and rotation characteristics are obtained through artificial intelligence (AI)-based machine learning. Then, the frequency characteristic is analyzed by performing a Fast Fourier transform on the obtained estimated value, and then the appropriateness of the measured value compared to the target frequency is evaluated by comparing it with the target inspection frequency. If the head rotation is inappropriate, a retry of the head rotation is requested, and then the same examination screen is reproduced again. On the other hand, when the proper head rotation is made, the effective section in which the rotation of the target range is made and the degree of head rotation (rotation angle, angular velocity, angular acceleration) are extracted (S4).

At the same time, after removing noises such as spontaneous eye movement, nystagmus, and eye blinking from the eye movement data, artificial intelligence (AI)-based machine learning is performed to obtain a precise estimate of eye rotation. Then, the frequency characteristic is analyzed by performing a Fast Fourier transform on the obtained estimated value, and the degree of eye rotation (rotation angle, angular velocity, angular acceleration) in an appropriate rotation section and frequency is extracted (S5).

Then, after calculating the degree of eye rotation (angle, angular velocity, angular acceleration) relative to the degree of head rotation (angle, angular velocity, angular acceleration) according to the following equation, vestibular-ocular reflex gain including at least one of them, and asymmetry A ratio is obtained and provided (S6).

That is, according to Equation 1, a rotation angle-based gain is calculated from the eyeball rotation angle versus the head rotation angle, and the maximum rotational angular velocity-based gain is calculated from the maximum eyeball rotation angular velocity versus the maximum head rotation angular velocity according to Equation 2, and Equation 3 After calculating the maximum rotational angular acceleration-based gain from the maximum eyeball rotation angular acceleration compared to the maximum head rotational angular acceleration according to to create and output.

[Equation 1]

[Equation 2]

[Equation 3]

In this case, the effective section means a section in which rotation of the target range identified through machine learning and Fourier transform-based analysis is made.

And the asymmetry ratio can be obtained according to Equation 4 below.

[Equation 4]

In this case, the degree of rotation is any one of a rotation angle, an angular velocity, and an angular acceleration.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

Claims (7)

a swivel chair that supports the subject's seating and rotation;
a head-wearable display device that is worn on the subject's head and covers the entire subject's eyes;
Eye tracker (eye tracker) for sensing the eye rotation of the subject;
a head movement sensor coupled to the head wearable display device and sensing a rotation pattern for an angle and speed of a head rotation of a subject; and
After generating an examination screen for providing a dark field and playing it through the head-wearable display device, the vestibular-eye reflex gain is calculated and quantified from the sensing results of the eye tracker and the head motion sensor to calculate and quantify the ratio of eye rotation to head rotation and a control device for calculating and providing at least one of:
The control device removes measurement noise from the head rotation data and the eyeball rotation data, obtains estimated values of the rotation amount and rotation characteristics through machine learning, and then performs a Fourier transform of the measured value versus the target frequency. Vestibular-ocular reflex function evaluation device based on virtual reality and biosignal sensor, characterized in that it evaluates the appropriateness. According to claim 1, wherein the control device
After generating and reimagining a test screen that induces preset head rotation and eye rotation, the vestibular-ocular reflex gain and asymmetry ratio are calculated and quantified by calculating and quantifying the ratio of eye rotation to head rotation from the sensing results of the eye tracker and the head motion sensor. Virtual reality and biosignal sensor-based vestibular-ocular reflex function evaluation device, characterized in that it further comprises a function of calculating and providing at least one of. According to claim 1, wherein the control device
A virtual reality and biosignal sensor-based system that configures and provides a test screen that induces preset head rotation and eye rotation, wherein the ratio of eye rotation to head rotation, and angle and speed of head and eye rotation can be adjusted in multiple steps Vestibular-ocular reflex function evaluation device. According to claim 1, wherein the control device
Calculate the rotational angle-based gain from the eyeball rotation angle versus the head rotation angle, calculate the maximum rotational angular velocity-based gain from the maximum eyeball rotational angular velocity versus the maximum head rotational angular velocity, and calculate the maximum rotational angular acceleration-based gain from the maximum eyeball rotational angular acceleration versus the maximum head rotational angular acceleration After calculating , at least one of the rotation angle-based gain, the maximum rotational angular velocity-based gain, and the maximum rotational angular acceleration-based gain is selected and provided as the vestibular-ocular reflection gain. of the vestibular-ocular reflex function evaluation device. According to claim 1, wherein the control device
"

"Calculate the asymmetry ratio according to the formula, wherein the right rotation degree and the left rotation degree are any one of a rotation angle, a rotation angular velocity, and a rotation angular acceleration. Functional evaluation device. According to claim 1, wherein the control device
If the head rotation does not come within the preset target frequency, after requesting a retry of the head rotation, the vestibular-ocular reflex function based on virtual reality and bio-signal sensor, characterized in that once again the vestibular-ocular reflex function evaluation operation is performed evaluation device. According to claim 1, wherein the swivel chair is
Vestibular-ocular reflex function evaluation device based on virtual reality and biosignal sensor, characterized in that it is rotated automatically under the control of the control device or manually rotated by a subject or an examiner.

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