KR20220068442A - Method and apparatus for measuring eye movement - Google Patents

Abstract

The present invention relates to a method and device for measuring an eye movement. According to an embodiment of the present invention, a method for measuring an eye movement includes the steps of: acquiring information related to an eyeball; determining an eye analysis model based on the acquired information related to the eyeball; acquiring an image of the eyeball in at least one cardinal position of gaze; and measuring the motion of the eyeball by analyzing the acquired eyeball image using the eyeball analysis model. According to the present invention, an eye movement range can be accurately and objectively measured.

Description

Method and apparatus for measuring eye movement

The present invention relates to a method and apparatus for measuring eye movement.

The human eyeball is moved by four straight muscles and two oblique muscles. The position of the eyeball is determined by the combination of forces applied to these muscles through neural control, the viscosity of the eyeball orbit, and the elasticity of the muscles. , both eyes move in the same direction at the same time.

However, problems with eye movement may occur due to various reasons such as aging or muscle abnormalities. Problems of such eye movement may include eye movement imbalance, eye muscle abnormality, eye movement disorder, strabismus, and the like. In order to diagnose and manage these problems, it is very important to measure the range of eye movement. In particular, if the performance content and degree of each type of eye movement can be accurately measured, it is possible to diagnose whether a related neural circuit is damaged or an ongoing disease or the like.

According to the prior art, most eye movement measurement methods rely on the examiner's experience and subjective judgment to roughly measure the value, and measure the eye movement based on the measured value, thereby reducing accuracy and making it difficult to standardize.

The present invention can provide a method and an apparatus for measuring eye movement that can quantitatively and accurately measure the movement range of the eyeball.

The method for measuring eye movement according to an embodiment of the present invention includes obtaining information related to the eyeball, determining an eye analysis model based on the obtained information related to the eyeball, and at least one or more basic positions of gaze (cardinal). positions of gaze) and measuring the movement of the eyeball by analyzing the acquired image of the eyeball using the eye analysis model.

According to an embodiment, the obtaining of the information related to the eye may include obtaining information related to the eye by measuring the eye, or information related to the eye from at least one of a measurement result of the eye and received information. may be obtained, or information related to the eye determined in advance according to the received information may be obtained.

According to an embodiment, the information related to the eye may include at least one of a size of the eyeball, a size of a cornea, a position of an eyelid crevice, and an age of the examinee.

According to an embodiment, the determining of the eye analysis model based on the obtained eye-related information may include determining the eye analysis model based on the size of the eyeball.

According to an embodiment, acquiring the image of the eyeball at the basic position of the at least one or more gazes may include acquiring an image of a left eye and an image of the right eye, respectively.

According to an embodiment, the basic position of the at least one or more gazes is a central position in which the eyeball faces the front, and at least one or more of the upper, lower, left, right, upper left, lower left, upper right, and lower right directions of the central position. It may include location.

According to an embodiment, the step of measuring the movement of the eyeball by analyzing the acquired image of the eyeball using the eyeball analysis model may include: Comparing the eyeball images at the basic position to obtain a difference value and determining the movement angle of the eyeball from reference data of the eyeball analysis model using the obtained difference value.

According to one embodiment, the step of obtaining a difference value by comparing the eyeball image at the central position in which the eyeball faces the front and the eyeball image at the basic position of the at least one or more gazes includes: the corneal limbus of the eyeball at the central position and comparing the position of the corneal limbus of the eyeball in the basic position of the at least one gaze.

According to an embodiment, the measuring the movement of the eyeball by analyzing the acquired image of the eyeball using the eye analysis model may include: The method may include selecting a reference image having a pixel value in which a sum of differences between pixel values from the eyeball image is minimized, and determining a movement angle of the eyeball from the selected reference image.

The device for measuring eye movements according to an embodiment of the present invention includes a camera unit, at least one memory storing a program for measuring eye movements, and executing the program to obtain information related to the eyeball, and to An eye analysis model is determined based on related information, an image of the eye is obtained at at least one or more cardinal positions of gaze, and the obtained eye image is analyzed using the eye analysis model to analyze the eyeball It may include at least one or more processors that control to measure the motion of the .

According to an embodiment, the at least one processor obtains information related to the eyeball by measuring the eyeball, or obtains information related to the eyeball from at least one of a measurement result of the eye and received information, Alternatively, it is possible to control to obtain predetermined information related to the eyeball according to the received information.

According to an embodiment, the information related to the eye may include at least one of a size of the eyeball, a size of a cornea, a position of an eyelid crevice, and an age of the examinee.

According to an embodiment, the at least one processor may control to determine the eyeball analysis model based on the size of the eyeball.

According to an embodiment, the one or more processors may control to acquire an image of a left eye and an image of a right eye, respectively.

According to an embodiment, the basic position of the at least one or more gazes is a central position in which the eyeball faces the front, and at least one or more of the upper, lower, left, right, upper left, lower left, upper right, and lower right directions of the central position. It may include location.

According to an embodiment, the at least one processor compares an eyeball image at a central position in which the eyeball faces the front and an eyeball image at a basic position of the at least one gaze to obtain a difference value, and the obtained difference Using the value, it is possible to control to determine the movement angle of the eyeball from the reference data of the eye analysis model.

According to an embodiment, the at least one processor may control to compare the position of the corneal limbus of the eyeball at the central position with the position of the corneal limbus of the eyeball at the basic position of the at least one gaze.

According to an embodiment, the at least one processor may be configured to: a reference having a pixel value in which a sum total of a difference between pixel values and an eye image at a basic position of the at least one gaze among the reference images of the eye analysis model is minimized It is possible to select an image and control to determine the movement angle of the eyeball from the selected reference image.

According to the present invention, it is possible to accurately and objectively measure the range of eye movement.

1 is a view for explaining a listing plane (Listing's Plane).
2 is a flowchart illustrating a method for measuring eye movement according to an embodiment of the present invention.
3 is a view for explaining a method for obtaining an eyeball image according to an embodiment of the present invention.
4 is a diagram illustrating a method for comparing eyeball images according to an embodiment of the present invention.
5 and 6 are diagrams illustrating results of eye movement measurement using the eye movement measurement method according to an exemplary embodiment.
7 is a diagram illustrating the configuration of an eye movement measuring apparatus according to an embodiment of the present invention.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art to which the present disclosure pertains can easily implement them. However, the present disclosure may be implemented in several different forms and is not limited to the embodiments described herein. In addition, in order to clearly explain the present disclosure in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Some embodiments of the present disclosure may be represented by functional block configurations and various processing steps. Some or all of these functional blocks may be implemented in various numbers of hardware and/or software configurations that perform specific functions. For example, the functional blocks of the present disclosure may be implemented by one or more microprocessors, or may be implemented by circuit configurations for a predetermined function. Also, for example, the functional blocks of the present disclosure may be implemented in various programming or scripting languages. The functional blocks may be implemented as an algorithm running on one or more processors. In addition, the present disclosure may employ prior art for electronic configuration, signal processing, and/or data processing, and the like.

In addition, the connecting lines or connecting members between the components shown in the drawings only exemplify functional connections and/or physical or circuit connections. In an actual device, a connection between components may be represented by various functional connections, physical connections, or circuit connections that are replaceable or added.

Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings.

1 is a view for explaining a listing plane (Listing's Plane).

Eye movements appear to be linear movements moving up and down, left and right, but in reality, the rotational center is located in the center of the eyeball. The eyeball rotates about an axis lying on the equatorial plane perpendicular to the line of sight, and this plane is called the listing plane. Listing's Law is a law that stipulates the orientation of the eyeball. The eyeball can reach from the primary position to the eyeball positions in all directions through one rotation around one axis lying in the Listing plane. The rule is that you can According to Listing's law, the primary position is a point where there is no torsion when a pure vertical or horizontal rotation is performed, that is, the rotation is zero. However, in general, the primary position is the same concept as the central position in which the eyeball is straight ahead, that is, the visual axis is parallel to the midsagittal plane of the head. is being used The secondary position refers to the position of the eyeball after only one pure horizontal or vertical rotation has occurred, such as adduction, abduction, superior rotation, and inversion, and the tertiary position is a combination of horizontal and vertical rotation from the central position. It refers to the position of the eyeball after rotation.

Referring to FIG. 1 , it shows that the eye can move by one rotation about one axis lying on the listing plane in moving from the primary position to the nine cardinal positions of gaze. For example, if the eyeball is facing upward and outward among the basic positions of the 9 gazes, the eye does not move to the corresponding position by doing abduction after abduction or abduction after abduction, as long as it is on the listing plane as shown in FIG. It can move by one rotation around its axis.

Accordingly, when the eyeball moves from the primary eye position, that is, the central position to the basic position of another gaze, it is possible to express the movement range of the eyeball as an angle. According to an embodiment, the range of motion expressed as an angle as described above may be measured.

2 is a flowchart illustrating a method for measuring eye movement according to an embodiment of the present invention.

First, in step 210, eye-related information is obtained. In an embodiment, the information related to the eye may be obtained by measuring the eyeball, obtaining predetermined information according to information received from the outside, or obtained from at least one of the measurement result of the eye and information received from the outside. have. Here, the eye-related information may include the size of the eyeball, the size of the cornea, the position of the eyelid crevice, the age of the examinee, and the like.

In an embodiment, the size of the eyeball, the size of the cornea, etc. of the examinee may be measured using an eyeball measuring device or an eye examining device. Here, the size of the eyeball may be inferred and/or calculated from the size of the cornea. In addition, the position of the eyelid crevice may be confirmed by photographing the subject's face or around the eyes with a camera. Furthermore, in one embodiment, as described above, as in the method of measuring the eyeball, information related to the eye is directly obtained If it is difficult to do so, predetermined information may be obtained according to information received from the outside, or may be obtained from at least one of an eye measurement result and information received from the outside. For example, information such as the age of the subject may be obtained by receiving a user input. Also, when the age of the subject is received through a user input, the size of the eyeballs of the subject may be inferred or estimated based on the age of the subject. Furthermore, information related to the eye of the subject may be acquired by using the above-described methods in combination. For example, the age of the subject may be received through a user input, the size of the eyeball of the subject may be inferred or estimated based on the age of the subject, and the position of the eyelid crevice may be acquired by photographing with a camera.

Thereafter, in step 220 , an eye analysis model is determined based on the obtained eye-related information. Here, the eye analysis model may be a model generated based on a database (DB) built based on eye-related information. In an embodiment, the eye analysis model may be determined based on the size of the eyeball. For example, there may be a plurality of different eye analysis models for each size of the eyeball, and based on the eye-related information obtained in step 210, the eyeball according to the size of the eyeball among a plurality of different eye analysis models for each size of the eyeball. It is possible to determine which eye analysis model to use for motion measurement.

In step 230, an image of the eyeball is acquired in at least one or more cardinal positions of gaze. In one embodiment, the basic position of the at least one or more gazes may include a central position in which the eyeball faces the front, and a position in at least one or more of the upper, lower, left, right, upper left, lower left, upper right, and lower right directions of the central position. can Hereinafter, 9 cardinal positions of gaze will be described as an example, but the present invention is not limited thereto, and an image of the eye may be obtained from the basic positions of 6 gazes or the basic positions of fewer or more gazes. .

In an embodiment, an image of the eye may be captured using a camera to obtain an image of the eyeball at at least one or more basic positions of the gaze. In this case, the image of the left eye and the image of the right eye may be acquired, respectively. That is, by using the camera to photograph the left eye and the right eye, respectively, the image of the left eye and the image of the right eye may be obtained, respectively. In an embodiment, the left eye and the right eye may be sequentially photographed using a single camera. In this case, the order in which the reference images of the left eye and the right eye are captured can be freely selected. In addition, using two cameras, one camera may photograph the left eye and the other camera may photograph the right eye to obtain an image of the left eye and an image of the right eye, respectively. In an embodiment, an image of one eye may be obtained by synthesizing the images of the left eye and the image of the right eye respectively obtained as described above. When taking an image of the eyeball using the camera, the subject's face may be fixed. This is because, when the position of the face of the photographer is changed, the direction of the gaze is changed, so that an image of another eye can be acquired. It will be described in more detail with reference to FIG. 3 .

3 is a view for explaining a method of acquiring an eyeball image according to an embodiment of the present invention.

Referring to FIG. 3 , the image of the eyeball in the 9 cardinal positions of gaze, that is, the central position, the upper, lower, left, right, upper-left, lower-left, upper-right, or lower-right positions of the central position can be obtained By acquiring images of the eyeballs at the basic positions of various gazes as described above, more accurate and objective eye movement measurement is possible. However, the basic position of the gaze shown in FIG. 3 is only an example, and comparison images may be obtained from various moving positions.

In one embodiment, a video of the eyeball rotated by 360 degrees is captured, and when the eyeball is in the default position of at least one gaze in the captured video, an eyeball image may be obtained by capturing a screen. That is, instead of photographing the eyeball at the basic position of each gaze, if the subject rotates the eyeball 360 degrees, the movement of the eyeball may be captured as a video, and an eyeball image may be obtained by capturing the captured video.

Thereafter, in step 240 , the eye movement is measured by analyzing the image of the eye obtained using the eye analysis model. In an embodiment, the movement of the eyeball may be measured by measuring or determining the movement angle of the eyeball by analyzing the image of the eyeball obtained using the eyeball analysis model.

In one embodiment, a difference value is obtained by comparing an eyeball image at a central position in which the eyeball faces the front with an eyeball image at a basic position of at least one gaze, and the obtained difference value is used to obtain reference data of the eye analysis model It is possible to determine the movement angle of the eyeball from More specifically, by comparing the eyeball image at the central position in which the eyeball faces the front and the eyeball image at the basic position of at least one gaze, the eyeball position, shape, It is possible to determine a difference between the eyeball image at the position and the eyeball image at the basic position of at least one gaze, and obtain it as a difference value. The reference data of the eyeball analysis model may include data on the movement angle of the eyeball corresponding to a difference value between the eyeball image at the central position and the eyeball image at the basic position of at least one gaze. Accordingly, it is possible to determine the movement angle of the eyeball based on the obtained difference value. For example, if the difference value is a, a+1, a+2, ..., a+N, the corresponding movement angle is preset to 5°, 10°, 15°, ..., 60°, etc. may have been decided. In an embodiment, as the interval between difference values included in the reference data of the eye analysis model is narrower, a more precise measurement result may be obtained. In addition, the correspondence between the difference value and the movement angle of the eyeball may be stored in the form of a table.

In an embodiment, when comparing the eye image at the central position in which the eyeball faces forward and the eye image at the primary position of the at least one gaze, the position of the corneal limbus of the eye in the central position and the primary position of the at least one gaze The position of the corneal limbus of the eye can be compared. It will be described in more detail with reference to FIG. 4 .

4 is a diagram illustrating a method for comparing eyeball images according to an embodiment of the present invention.

Referring to FIG. 4 , the position of the corneal limbus in the eyeball image at the central position in which the eyeball faces the front and the eyeball image at the basic position of at least one gaze may be compared. More specifically, a point of the corneal limbus located on a straight line passing through the center of the pupil may be compared in the eye image at the central position in which the eyeball faces the front and the eye image at the basic position of at least one gaze. For example, by overlapping the eyeball image at the central position and the eyeball image at the basic position of at least one or more gaze, the extension line of a straight line passing through the pupil center and the pupil center in the comparison image and the corneal limbus in the reference image and a point where the corneal limbus meets each in the comparison image may be measured.

Returning to the description of FIG. 2 , in one embodiment, the reference image having a pixel value in which the sum of the difference in pixel values with the eye image at the basic position of at least one gaze among the reference images of the eye analysis model is minimized may be selected, and the movement angle of the eye may be determined from the selected reference image. More specifically, among the reference images of the eye analysis model, the reference image in which the following [Equation 1] has a minimum value is selected.

[Equation 1]

Here, Pixa is a pixel value of an eyeball image at the basic position of at least one or more gazes, and Pixb is a pixel value of a reference image of the eye analysis model.

That is, in one embodiment, selecting the reference image having a pixel value in which the sum of differences in pixel values of the image of the eye obtained in step 230 is minimized is to select the reference image obtained in step 230 from among the reference images stored in the eye analysis model. It selects the image that is most similar to the image of In the eye analysis model, data on the movement angle of the eye in each reference image may be included. Accordingly, when the reference image is selected, the movement angle of the eye corresponding thereto can be known. In an embodiment, as the number of reference images of the eye analysis model increases, a more precise measurement result may be obtained. In addition, the correspondence between the reference image and the movement angle of the eyeball may be stored in the form of a table.

5 and 6 are diagrams illustrating results of eye movement measurement using the eye movement measurement method according to an exemplary embodiment.

5 and 6 , the movement range of the eyeball for each of the nine cardinal positions of gaze except for the central position, that is, upper, lower, left, right, upper left, lower left, upper right, or lower right position. is displayed in degrees.

According to an embodiment of the present invention, as described above, since the eye movement range can be expressed in specific numerical values, accurate and objective eye movement measurement is possible.

5 is a measurement result of eye movement of a normal person, and FIG. 6 is a measurement result of eye movement of a patient with duane retraction syndrome. Based on the range of eye movement measured in this way, diseases such as exotropia, esotropia, paralytic strabismus, thyroid ophthalmopathy, myasthenia gravis, Brown syndrome, chronic progressive external ocular muscle paralysis, duane retraction syndrome, and orbital rupture fracture can be diagnosed. .

7 is a diagram showing the configuration of an eye movement measuring apparatus according to an embodiment of the present invention.

Referring to FIG. 7 , the apparatus 700 for measuring eye movement according to an embodiment may include a camera unit 710 , a memory 720 , and a processor 730 . However, the present invention is not limited thereto, and the eye movement measuring apparatus 700 may be implemented by more or fewer components than all of the components shown in FIG. 7 .

In FIG. 7 , the eye movement measuring apparatus 700 is illustrated as including one processor, but the embodiment is not limited thereto, and may include a plurality of processors. At least some of the operations and functions of the processor 730 described below may be performed by a plurality of processors. The eye movement measurement apparatus 700 illustrated in FIG. 7 may perform a method for eye movement measurement according to various embodiments of the present disclosure, and the description of FIGS. 1 to 6 may be applied. Accordingly, content overlapping with the above will be briefly described.

The camera unit 710 may include a camera sensor (not shown) that photographs a subject and converts an optical signal into an electrical signal, and a signal processor (not shown) that converts an analog image signal into digital data. Here, the camera sensor may be a charge coupled device (CCD) sensor or a complementary metal semiconductor (CMOS) sensor, and the signal processing unit may be implemented as a digital signal processor (DSP). In addition, the camera sensor and the signal processing unit may be implemented integrally or may be implemented separately. The camera unit 710 captures an image when a user's shooting command is input. In an embodiment, the camera unit 710 may transmit an image obtained by photographing the eyeball to the memory 720 and/or the processor 730 under the control of the processor 730 .

The memory 720 may be installed and stored in various types of data such as programs and files such as applications. The processor 730 may access and use data stored in the memory 720 , or may store new data in the memory 720 . In an embodiment, a program and data for measuring eye movement may be installed and stored in the memory 720 .

The processor 730 controls the overall operation of the eye movement measuring apparatus 700 , and may include at least one processor such as a CPU or GPU. The processor 730 may control other components included in the eye movement measurement apparatus 700 to perform an operation for measuring the eye movement. In addition, the processor 730 may execute a program stored in the memory 720 , read a stored file, or store a new file.

In one embodiment, the processor 730 by executing the program stored in the memory 720, obtains eye-related information, determines an eye analysis model based on the obtained eye-related information, and It is possible to obtain an image of the eyeball in the cardinal positions of gaze, and control to measure the movement of the eyeball by analyzing the image of the eye obtained using an eye analysis model. In addition, the processor 730 measures the eyeball to obtain eyeball-related information, obtains eyeball-related information from at least one of a measurement result and received information of the eyeball, or obtains eyeball-related information according to the received information. It can be controlled to obtain related information. Here, the eye-related information may include the size of the eyeball, the size of the cornea, the position of the eyelid crevice, the age of the examinee, and the like. In addition, the basic position of the at least one or more gazes may include a central position in which the eyeball faces the front, and a position in at least one of directions above, below, left, right, upper left, lower left, upper right, and lower right of the central position.

In an embodiment, the processor 730 may control to determine the eye analysis model based on the size of the eyeball. In addition, the processor 730 may control to acquire the image of the left eye and the image of the right eye, respectively.

In one embodiment, the processor 730 compares the eyeball image at the central position in which the eyeball faces the front with the eyeball image at the basic position of at least one or more gazes to obtain a difference value, and analyzes the eyeball using the obtained difference value It can be controlled to determine the movement angle of the eyeball from the reference data of the model. In addition, the processor 730 may control the position of the corneal limbus of the eyeball at the central position to be compared with the position of the corneal limbus of the eyeball at at least one or more basic positions of the gaze.

In one embodiment, the processor 730 selects a reference image having a pixel value in which the sum of the difference in pixel values with the eye image at the basic position of at least one gaze from among the reference images of the eye analysis model is minimized, It can be controlled to determine the movement angle of the eyeball from the selected reference image.

Meanwhile, the above-described embodiment can be written as a program that can be executed on a computer, and can be implemented in a general-purpose digital computer that operates the program using a computer-readable medium. In addition, the structure of the data used in the above-described embodiment may be recorded in a computer-readable medium through various means. In addition, the above-described embodiment may be implemented in the form of a computer program product including a recording medium including instructions executable by a computer, such as a program module executed by a computer. For example, methods implemented as a software module or algorithm may be stored in a computer-readable recording medium as computer-readable codes or program instructions.

Computer-readable media may be any recording media that can be accessed by a computer, and may include volatile and nonvolatile media, removable and non-removable media. The computer readable medium may include a magnetic storage medium, for example, a ROM, a floppy disk, a hard disk, and the like, and an optically readable medium, for example, a storage medium such as a CD-ROM or DVD, but is not limited thereto. . Additionally, computer-readable media may include computer storage media and communication media.

In addition, a plurality of computer-readable recording media may be distributed in network-connected computer systems, and data stored in the distributed recording media, for example, program instructions and codes may be executed by at least one computer. have.

Although embodiments of the present disclosure have been described with reference to the above and the accompanying drawings, those of ordinary skill in the art to which the present invention pertains can practice the present invention in other specific forms without changing its technical spirit or essential features. You will understand that there is Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

700: eye movement measurement device
710: camera unit
720: memory
730: processor

Claims (7)

obtaining information related to the eyeball;
determining an eye analysis model based on the obtained eye-related information;
acquiring an image of the eyeball in at least one or more basic positions of gaze; and
Analyzing the acquired image of the eyeball using the eyeball analysis model comprising the step of measuring the movement of the eyeball, the eye movement measurement method. The method of claim 1,
The step of obtaining information related to the eyeball includes:
Obtaining information related to the eyeball by measuring the eyeball, obtaining information related to the eyeball from at least one of a measurement result of the eyeball and received information, or obtaining information related to the eyeball predetermined according to the received information A method of measuring eye movement to obtain information. The method of claim 1,
The eye-related information,
Including at least one or more of the size of the eyeball, the size of the cornea, the position of the eyelid crevice, and the age of the subject,
Determining an eye analysis model based on the obtained eye-related information includes:
and determining the eye analysis model based on the size of the eyeball. The method of claim 1,
The step of acquiring an image of the eyeball at the basic position of the at least one gaze,
A method of measuring eye movement, comprising acquiring an image of a left eye and an image of the right eye, respectively. The method of claim 1,
Measuring the movement of the eyeball by analyzing the image of the obtained eyeball using the eye analysis model,
obtaining a difference value by comparing an eyeball image at a central position in which the eyeball faces the front with an eyeball image at a basic position of the at least one gaze; and
and determining the movement angle of the eyeball from reference data of the eye analysis model by using the obtained difference value. 6. The method of claim 5,
Comparing the eyeball image at the central position in which the eyeball faces the front and the eyeball image at the basic position of the at least one gaze to obtain a difference value,
Comprising the step of comparing the position of the corneal limbus of the eyeball at the central position and the position of the corneal limbus of the eyeball at the basic position of the at least one or more gazes, the eye movement measurement method. The method of claim 1,
Measuring the movement of the eyeball by analyzing the image of the obtained eyeball using the eye analysis model,
selecting, among the reference images of the eye analysis model, a reference image having a pixel value in which a sum total of a difference between pixel values and an eye image at a basic position of the at least one gaze is minimized; and
Including the step of determining the movement angle of the eyeball from the selected reference image, eye movement measurement method.

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