JP5981858B2 - Balance function inspection device - Google Patents

Description

  The present invention relates to a balance function testing device, and more particularly to a balance function testing device that images the movement of an eyeball in a balance function test.

  In otolaryngology, neurology, neurosurgery, etc., in the treatment of dizziness or balance dysfunction, how the eyeball moves in response to eye stimulation, head stimulation, or ear stimulation Equilibrium function tests are widely conducted. This balanced function test detects, for example, various accelerations caused by the human body by comparing eye movements with a healthy person by stimulating the head horizontally, more specifically, by stimulating the neck to the left or right. Check for abnormalities in the balance function system such as the vestibule and the semicircular canal.

  For balance function tests, vestibular eye reflex (VOR: VESTIBULO-OCULAR REFLEX), natural vision vestibular reflex (Vis-VOR: VISUAL-VESTIBULO-OCULAR REFLEX), fixation vestibule reflex (VOR-FIX: FIXATION SUPPRESSION OF THE) Some test VESTIBULO-OCULAR REFLEX).

  As a method for recording and observing eye movements used for such an equilibrium function test, there are visual observation, observation under Frenzel glasses, chromography, movie shooting, video recording, electrical or optical recording method, electromagnetic recording method and the like. In recent years, the electro-hybridometer (ENG: ELECTRO-NYSTAGMOGRAPHY), which is an electrical recording method, the search coil method, which is an electromagnetic recording method, or the eyeball is imaged with a video camera, and the moving image is observed and recorded The method of doing is attracting attention. By using these methods, objective eye movement data can be obtained. A specific configuration of the balance function inspection apparatus is disclosed in Patent Document 1, for example.

  One of the methods for analyzing eye movements from data obtained from the balance function testing apparatus is an analysis method using vestibulo-ocular reflex. Vestibulo-oculomotor reflex is a reflection in which the eyeball moves in the opposite direction when the head is rotated. When acceleration stimulation in a certain direction continues, the eyeball is gradually displaced in the opposite direction and rapidly Repeat the regular movement to return to the original. Of the repetitive eye movements, the part where the eyeball position is gradually displaced is called the slow phase, and the part where the eyeball position returns rapidly to the original position is called the rapid phase. The phenomenon in which these two phases appear alternately is known as nystagmus, and the time series data of this nystagmus is called nystagmus data (eyeball vibration data).

  When analyzing vestibulo-oculomotor reflexes from nystagmus data and using it to diagnose dizziness, nystagmus data is included in the rapid phase caused by the central action of the cerebellum and the slow phase caused by vestibulo-ocular reflex. Needed to be separated properly.

  The balance function inspection apparatus disclosed in Patent Document 1 includes an infrared CCD camera for imaging the movement of the eyeball. The infrared CCD camera outputs charges generated by imaging to the image processing apparatus as analog imaging signals. The image processing apparatus digitizes the imaging signal from the infrared CCD camera and records the movement of the eyeball. In the balanced function testing apparatus disclosed in Patent Document 2, a target is presented on a screen with a laser pointer or the like, or the position of the target is changed, and a visual stimulus is given to the eyeball with the target to move the eyeball. Equilibrium function test can be performed.

JP-A-9-285468 JP 11-225968 A

  However, in the conventional balance function testing apparatus, in order to measure the delay time from the application of the visual stimulus by the presentation of the target or the change of the position to the reaction of the eyeball, the interval between capturing the images is shortened (for example, The sampling rate must be as high as about 240 Hz), and it is necessary to digitize the imaging signal from the CCD camera, and an expensive image processing apparatus must be employed. For this reason, the conventional balance function inspection apparatus cannot provide an inexpensive apparatus.

  Furthermore, in the conventional balance function testing apparatus, it is not always possible to acquire an image of the eyeball when the visual stimulus is applied even if the interval for capturing the image is shortened. In other words, the delay time from when the visual stimulus was applied to when the eyeball responded could not always be accurately measured.

  Therefore, the present invention has been made to solve the above-described problems, and provides an equilibrium function testing apparatus that can always accurately measure the delay time from the application of visual stimulation to the reaction of the eyeball. The purpose is to do.

An equilibrium function inspection apparatus according to the present invention is an equilibrium function inspection apparatus that acquires eye movement data in an equilibrium function inspection. An imaging apparatus that images eye movement and an image captured by the imaging apparatus are predetermined. An image capturing unit that captures at intervals, a target generating unit that generates a target for visual recognition by the subject, a target generated by the target generating unit is presented to the subject , and the target A target presentation unit for changing the position; a control unit for capturing an image in the image capturing unit; a target presentation or position change in the target presentation unit; and a control unit for controlling the position of the target. The first timing for capturing an image in the image capturing unit is synchronized with the second timing for starting the presentation or position change of the target in the target presentation unit.

  Preferably, the control unit starts to cause the target presentation unit to start presenting the target or changing the position based on the timing when the image capturing signal for capturing the image from the imaging device to the image capturing unit is given. By generating the signal, the second timing of the visual target presenting unit is synchronized with the first timing of the image capturing unit.

  Preferably, the control unit starts the capturing of the image from the imaging device to the image capturing unit based on a start signal for causing the target presenting unit to start presenting the target or changing the position thereof, so that the target presenting unit The first timing of the image capturing unit is synchronized with the second timing.

  Preferably, the control unit, based on an internally generated internal clock signal, an image capture signal for capturing an image from the imaging device to the image capture unit, and a target presentation or position change in the target presentation unit Is generated, and the first timing of the image capturing unit and the second timing of the visual target presenting unit are synchronized.

  Preferably, the control unit, based on an external clock signal input from the outside, an image capture signal for capturing an image from the imaging device to the image capture unit, and a change in the target presentation or position on the target presentation unit Is generated, and the first timing of the image capturing unit and the second timing of the visual target presenting unit are synchronized.

  Preferably, the control unit includes an adjustment time setting unit that sets an adjustment time from when the start signal is input to the visual target presenting unit to when the display of the visual target or the change of the position is started to the subject. The control unit delays the first timing of the image capturing unit by the adjustment time set in the adjustment time setting unit and synchronizes with the second timing of the visual target presentation unit.

  Preferably, the optotype presenting unit includes a reflecting unit that reflects the optotype generated by the optotype generating unit and a position changing unit that changes a position of the reflecting unit, and the control unit is a reflection that is changed by the position changing unit. By controlling the position of the unit, presentation of the target or change of the position in the target presentation unit is controlled.

  Preferably, the control unit is configured to analyze an eyeball movement data sampled in time series from an analysis unit that analyzes the position of the eyeball from the image captured by the image capturing unit and the position of the eyeball analyzed by the analysis unit. And a data interpolation unit for interpolation.

  Preferably, the data interpolation unit interpolates between sampling of eye movement data by spline interpolation.

  The balance function inspection apparatus according to the present invention synchronizes the first timing for capturing an image in the image capturing unit and the second timing for starting the target presentation or position change in the target presentation unit, When measuring the delay time from when the visual stimulus is given by the presentation of the target or the change of the position to when the eyeball reacts, the measurement start point can always be made constant. Therefore, the balance function testing apparatus according to the present invention is a balance function test in which a visual stimulus is applied to the eyeball to examine the reaction, even if the target moves rapidly or slowly, It is possible to always accurately measure the delay time from when a visual stimulus is applied to when the eyeball reacts. Furthermore, the balance function inspection apparatus according to the present invention always provides a delay time from when a visual stimulus is applied to when the eyeball reacts, even if an inexpensive imaging device and an image capturing unit that capture images are long. Since it can measure accurately, an inexpensive apparatus can be provided.

It is the schematic which shows the basic composition of the balanced function inspection apparatus which concerns on embodiment of this invention. It is the schematic for demonstrating the visual target shown to a subject with the balanced function test | inspection apparatus which concerns on embodiment of this invention. It is a figure for demonstrating an eyeball position. It is a figure which shows an example of the nystagmus data which arranges eyeball position data in time series, and two phases, a slow phase and a rapid phase, appear alternately. It is a figure for demonstrating the angular velocity of the eyeball calculated from the nystagmus data shown in FIG. It is a figure explaining the synchronous timing which synchronizes an image capture signal and a start signal. It is a figure which shows an example of the change of the position of the eyeball detected with the balanced function inspection apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the change of the angular velocity of the eyeball detected with the balanced function inspection apparatus which concerns on embodiment of this invention. It is a figure which shows an example which is not synchronizing the image capture timing which takes in an image, and the start timing which starts presentation of a target or a change of a position in the change of the position of the eyeball detected with the balance function test | inspection apparatus. It is a figure which shows an example which synchronizes the image capture timing which takes in an image, and the start timing which starts the presentation of a target or a change of a position in the change of the position of the eyeball detected with the balance function test | inspection apparatus. It is a figure which shows the delay time after giving a visual stimulus in each position of an eyeball until an eyeball reacts. It is the schematic which shows the basic composition of the balanced function inspection apparatus which concerns on the modification 1 of this invention. It is the schematic which shows the basic composition of the balanced function inspection apparatus which concerns on the modification 2 of this invention. It is the schematic which shows the basic composition of the balanced function inspection apparatus which concerns on the modification 3 of this invention. It is a figure explaining the synchronous timing of the balanced function inspection apparatus which concerns on the modification 4 of this invention.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
(Embodiment)
FIG. 1 is a schematic diagram showing a basic configuration of a balanced function testing apparatus according to an embodiment of the present invention. The balance function testing apparatus 100 shown in FIG. 1 records the movement of the eyeball E, measures the nystagmus of the eyeball E, or measures the delay time from the application of the visual stimulus to the reaction of the eyeball E. Do. The balance function testing apparatus 100 includes an imaging camera 1 configured with a CCD (Charge Coupled Device) camera, a computer 2 configured with a personal computer, a laser pointer 3 that generates a visual target for applying visual stimulation to the eyeball E, And a target presentation unit 4 for changing the position of the target. Although not shown, the balance function testing apparatus 100 may include a head movement sensor that measures the movement of the head of the subject.

  The balance function testing apparatus 100 gives a predetermined stimulus to the subject's head, observes the vestibular eye reflex, the natural vestibule reflex, and the fixation vestibule reflex, and the movement of the eyeball E at this time is an imaging camera. 1 for imaging. Furthermore, the balance function testing apparatus 100 presents or changes the position of the visual target generated by the laser pointer 3 to the subject and gives visual stimulation to the eyeball E, and the movement of the eyeball E at this time is captured by the imaging camera 1. Take an image with. As a configuration for imaging the movement of the eyeball E, for example, there is a balanced function inspection device disclosed in Japanese Patent Laid-Open No. 9-285468 (Japanese Patent No. 3455638). The configuration proposed for the balance function testing apparatus is a goggle-type eyeball observation wearing device. The subject wears this goggles and rotates the head, etc. Take an image. In addition, in the balanced function testing apparatus disclosed in, for example, Japanese Patent Laid-Open No. 11-225968 (Patent No. 3812259), a laser pointer is provided on an eye movement observation wearing tool or an examination chair, and the laser pointer is generated by the laser pointer. The target is presented to the subject or the position thereof is changed, and the movement of the eyeball is captured by the imaging camera.

  In the balanced function testing apparatus 100, the visual target generated by the laser pointer 3 is directly presented to the eyeball E via the half mirror 1a, and visual stimulation is given to the eyeball E. And the imaging camera 1 images the movement of the eyeball E which gave visual stimulation via the half mirror 1a. The moving image captured by the imaging camera 1 is output to the computer 2 in the form of a video signal, and is captured from the video input board 21 of the computer 2. The video input board 21 samples the captured moving image of the eyeball E for each frame or field, binarizes the sampled image, and detects the motion center O (see FIG. 4) of the eyeball E by the ellipse approximation method. To do. Furthermore, the computer 2 performs predetermined calculation processing, and calculates the angular position of the pupil center with respect to the movement center O of the eyeball E as eyeball position data. A method for obtaining the center of motion O of the eyeball E from the image of the eyeball E using the ellipse approximation method is disclosed in detail in Japanese Patent Laid-Open No. 8-145644.

  The visual target presentation unit 4 includes a galvano mirror 41 that reflects the visual target generated by the laser pointer 3 and a galvano controller 42 that changes the position of the galvano mirror 41. And the position of the visual target shown to the eyeball E can be changed because the galvano controller 42 changes the position of the galvanometer mirror 41. FIG. That is, the computer 2 outputs a galvano control signal from an analog / digital conversion board (hereinafter referred to as an AD board) 22 to the galvano controller 42, changes the position of the galvano mirror 41, and controls the visual target presented to the eyeball E. doing. Here, “changing the position of the galvanometer mirror” is a concept including “changing the direction of the galvanometer mirror”.

  The computer 2 stores data obtained by arranging the calculated eyeball position data in time series in a storage unit (not shown). The data stored in the storage unit can be saved as a file in an external storage medium, transmitted to the outside via a LAN, and analyzed by an analysis unit described later.

  As the head motion sensor, an angular velocity sensor, an angle sensor, an angular acceleration sensor, or the like is used, and a measurement signal corresponding to the motion of the subject's head is output. The computer 2 takes in the measurement signal via the AD board 22 and stores it in a storage unit (not shown) in synchronization with the eyeball position data. As disclosed in, for example, Japanese Patent Laid-Open No. 11-225967 (Patent No. 3730005), the computer 2 stores eye position data stored in the storage unit and data such as the angular velocity of the head movement based on the measurement signal. By analyzing in combination, data analyzed as more reliable diagnostic data can also be used.

  In the balance function testing apparatus 100 shown in FIG. 1, the configuration in which the visual target generated by the laser pointer 3 is directly presented to the eyeball E via the half mirror 1a has been described, but the present invention is not limited to this. For example, a configuration in which a visual target generated by the laser pointer 3 is projected on a screen and presented to the eyeball E may be employed. FIG. 2 is a schematic diagram for explaining a visual target to be presented to a subject by the balanced function testing apparatus according to the embodiment of the present invention. FIG. 2 shows a screen 5 for projecting the target S generated by the laser pointer 3, and shows how the position of the target S moves left and right by changing the position of the galvano mirror 41. It is. The position of the index S may move up and down or up and down and left and right instead of right and left.

  The computer 2 includes a video input board 21 and an AD board 22, and also includes an analysis unit 23, a data interpolation unit 24, and an adjustment time setting unit 25. The analysis unit 23, the data interpolation unit 24, and the adjustment time setting unit 25 are configured by software executed by the computer 2, but the present invention is not limited to this, and each unit is configured as dedicated hardware. May be.

  Next, the analysis unit 23 analyzes the data in which the eyeball position data is arranged in time series, and separates the data into a slow phase and a rapid phase, and measures the delay time from when a visual stimulus is given to when the eyeball E reacts. To do. First, the eyeball position and nystagmus data in which the eyeball position data are arranged in time series will be described. FIG. 3 is a diagram for explaining the eyeball position. FIG. 4 is a diagram illustrating an example of nystagmus data in which eyeball position data is arranged in time series and two phases of a slow phase and a rapid phase appear alternately.

  In FIG. 3, an eyeball E viewed in the xy plane or the yz plane is shown. The position where the y-axis direction is the front and the eyeball E faces the front is the reference position e0. The angle between the reference position e0 and the position e1 where the eyeball E has moved around the movement center O is the eyeball position θ. The eyeball position θ has a component of an angle θxy on the xy plane and a component of an angle θyz on the yz plane. Therefore, in the present embodiment, the eyeball position θ is expressed as a root mean square (RMS) or a mean square deviation value between the angle θxy and the angle θyz. In addition, although the root mean square of the angle θxy and the angle θyz is the eyeball position θ, the analysis may be performed by separately using each angle as the eyeball position.

  The nystagmus data shown in FIG. 4 shows the time change of the eyeball position θ, and is data in which two phases, a slow phase and a rapid phase, appear alternately. In the nystagmus data shown in FIG. 4, the eyeball position θ gradually increases in the slow phase, and the eyeball position θ rapidly changes in the rapid phase.

  The analysis unit 23 calculates the angular velocity (angle / second) of the eyeball E by taking the difference between the data of the adjacent eyeball positions θ in order to separate the nystagmus data into the slow phase and the rapid phase. FIG. 5 is a diagram for explaining the angular velocity of the eyeball E calculated from the nystagmus data shown in FIG. The graph of the angular velocity of the eyeball E shown in FIG. 5 shows how the movement of the eyeball E, which was slow in the slow phase period, suddenly changes to a fast angular velocity in the rapid phase period. Therefore, as can be seen from FIG. 5, if a threshold is set between the angular velocity of the slow phase and the angular velocity of the rapid phase, the nystagmus data can be separated into the slow phase and the rapid phase.

  Next, the analysis unit 23 determines the position of the eyeball E when the visual stimulus is given by the presentation of the target S or the change of the position in order to measure the delay time from when the visual stimulus is given until the eyeball E reacts. Need to get. For this purpose, it is necessary to capture an image of the eyeball E when the video input board 21 gives a visual stimulus by the presentation of the target S or the change of the position. Therefore, the computer 2 captures an image of the eyeball E from the video input board 21 when the visual stimulus is given by the presentation of the target S or the change of the position from the video input board 21. Is output. The AD board 22 generates a galvano control signal that causes the galvano controller 42 to start presenting the target S or changing the position based on the timing at which the image capture signal is given. In the present embodiment, the galvano control signal for causing the galvano controller 42 to start presenting the target S or changing the position is referred to as a start signal.

  The computer 2 causes the AD board 22 to generate a start signal for starting the presentation of the target S or the change of the position based on the timing when the image capture signal is given, so that the image capture timing of the video input board 21 is set. The start timing of the galvano controller 42 is synchronized. FIG. 6 is a diagram for explaining the synchronization timing for synchronizing the image capture signal and the start signal. As shown in FIG. 6, the AD board 22 matches the rising timing of the start signal with a certain rising timing of the image capture signal output from the video input board 21. Thereby, the rise timing (start timing) of the start signal and the rise timing (image capture timing) of the image capture signal are synchronized. This timing is called a synchronization timing. In FIG. 6, the start signal is expressed as a single pulse signal. However, the present invention is not limited to this, and in order to start presentation of the target S or change of position in the galvano control signal. Any signal may be used as long as the signal is input first.

  When the start signal is input, the galvano controller 42 changes the position of the galvano mirror 41 and presents the target S generated by the laser pointer 3 to the eyeball E or the position of the target S that has been presented. change. In synchronization with the synchronization timing, the video input board 21 captures the image of the eyeball E captured by the imaging camera 1. Therefore, the computer 2 can always acquire the image of the eyeball E when the visual stimulus is given by the presentation of the target S or the change of the position from the video input board 21, and by the presentation or the change of the position of the target S. The position of the eyeball E when the visual stimulus is given can be acquired. Therefore, the analysis unit 23 can always accurately measure the delay time from when the visual stimulus is given to when the eyeball E reacts.

  A specific example will be used to explain that the balance function testing apparatus 100 according to the embodiment of the present invention always accurately measures the delay time from when a visual stimulus is applied to when the eyeball E reacts. FIG. 7 is a diagram illustrating an example of a change in the position of the eyeball E detected by the balance function testing device according to the embodiment of the present invention. Moreover, FIG. 8 is a figure which shows an example of the change of the angular velocity of the eyeball E detected with the balance function test | inspection apparatus which concerns on embodiment of this invention.

  The graphs shown in FIGS. 7 and 8 were obtained as a result of a follow-up eye movement test (or visual stimulus test) for examining how the eyeball E of the subject follows the target S. Data is graphed. The graph shown in FIG. 7 shows the change in the position of the eyeball E from the 116.3th to 117.0th measurement time, where the horizontal axis is time (seconds) and the vertical axis is the position (angle) of the eyeball E. Plotted. Note that the plot of the position of the eyeball E is determined by the image sampled by the video input board 21. The graph shown in FIG. 7 shows a plot (black square) when the video input board 21 acquires an image at a high sampling rate of 240 Hz (the interval at which images are captured is short), and the video input board 21 is 60 Hz. A plot (white circle) when an image is acquired at a low sampling rate (a long interval between capturing images) is shown. Furthermore, the graph shown in FIG. 7 also shows the position (angle) of the target S (laser) with respect to the measurement time.

  First, the target S is fixed at a position of 10 degrees from the measurement time 116.3 seconds to about 116.45 seconds, and the eyeball E follows the target S and is at the same position of 10 degrees. is there. Thereafter, the visual target S changes to a position of −10 degrees at about 116.45 seconds of the measurement time. At this time, since the start timing of the galvano controller 42 is synchronized with the image capture timing of the video input board 21, the position of the galvano mirror 41 is changed by the galvano controller 42, and the target S is changed to a position of -10 degrees. The video input board 21 can acquire an image at the time point. That is, as shown in FIG. 7, the plot of the position of the eyeball E (black square and white circle) overlaps with the point where the target S starts changing from the 10 degree position to the -10 degree position.

  Furthermore, after the target S is changed to a position of −10 degrees, the eye E can not follow the change of the target S from about 116.45 seconds to about 116.65 seconds of the measurement time. Located at 10 degrees. Thereafter, the eyeball E moves from the position of 10 degrees to the position of −10 degrees between about 116.65 seconds and about 116.73 seconds of the measurement time. Then, after about 116.73 seconds of the measurement time, the eyeball E follows the target S and is at the same position of −10 degrees.

  The analysis unit 23 measures a delay time from when the visual stimulus is given to when the eyeball E reacts, based on the result of the graph shown in FIG. Specifically, the analysis unit 23 sets the eyeball E at the position of −10 degrees from the image of the position of the eyeball E plotted at the point where the target S starts changing from the position of 10 degrees to the position of −10 degrees. Is measured as a delay time from when the visual stimulus is applied to when the eyeball E reacts. Specifically, the analysis unit 23 measures 0.29 seconds from about 116.45 seconds to about 116.73 seconds of the measurement time, the delay time from when the visual stimulus is applied until the eyeball E reacts, and the measurement. To do.

  In the balanced function testing apparatus 100, since the start timing of the galvano controller 42 is synchronized with the image capture timing of the video input board 21, a plot (white circle) when an image is acquired at a low sampling rate of 60 Hz. Even so, it overlaps with the point where the target S starts changing from the position of 10 degrees to the position of -10 degrees. Therefore, the balanced function testing apparatus 100 does not need to employ the expensive video input board 21 and the imaging camera 1 that can acquire an image at a high sampling rate of 240 Hz, and can acquire an image at a low sampling rate of 60 Hz. Such an inexpensive video input board 21 and imaging camera 1 can be employed. As a result, an inexpensive balance function inspection device 100 can be provided.

  Further, the computer 2 includes a data interpolation unit 24. As shown in the graph of FIG. 7, when an image is acquired at a low sampling rate of 60 Hz, a period during which the position of the eyeball E changes significantly (for example, from about 116.65 seconds to about 116.73 seconds of measurement time). The interval between plots is wider than when an image is acquired at a high sampling rate of 240 Hz. That is, when an image is acquired at a low sampling rate of 60 Hz in the period, the computer 2 cannot measure the change in the position of the eyeball E in detail.

  Therefore, the data interpolation unit 24 performs spline interpolation between sampling of the position data (movement data) of the eyeball E when an image is acquired at a low sampling rate of 60 Hz. The position data of the eyeball E subjected to the spline interpolation is close to the plot interval of the position data of the eyeball E when an image is acquired at a high sampling rate of 240 Hz, as in the plot (white square) of the graph shown in FIG. . Therefore, the position data of the eyeball E subjected to the spline interpolation has a plot interval equivalent to that obtained when an image is acquired at a high sampling rate of 240 Hz even during a period in which the position change of the eyeball E is large. Therefore, the computer 2 can measure the change in the position of the eyeball E finely by performing the spline interpolation on the position data of the eyeball E by the data interpolation unit 24 as in the case of acquiring an image at a high sampling rate.

  The data interpolation unit 24 performs spline interpolation on the position data of the eyeball E. However, the present invention is not limited to this, and other interpolation methods such as Lagrange interpolation and polynomial interpolation may be used. .

  Next, in the graph shown in FIG. 8, the horizontal axis is time (seconds) and the vertical axis is the angular velocity (angle / second) of the eyeball E, as in the graph shown in FIG. The change in the angular velocity of the eyeball E up to the 0th second is plotted. It should be noted that the plot of the angular velocity of the eyeball E is obtained from the difference in the position of the eyeball E determined by the image sampled by the video input board 21. The graph shown in FIG. 8 is a plot (black square) when the video input board 21 acquires an image at a high sampling rate of 240 Hz (the interval at which the image is captured is short), and the video input board 21 is 60 Hz. A plot (white circle) when an image is acquired at a low sampling rate (a long interval between capturing images) is shown. Further, the graph shown in FIG. 8 also shows the angular velocity (angle / second) of the target S (laser) with respect to the measurement time.

  First, from the measurement time of 116.3 seconds to about 116.45 seconds, since the target S is fixed at a position of 10 degrees, the angular velocity of the target S becomes 0 (zero) angle / second, The angular velocity of the eyeball E following the mark S is also 0 (zero) angle / second. Thereafter, the target S changes to a position of −10 degrees at about 116.45 seconds of the measurement time, so that the angular velocity of the target S is −800 angles / second. At this time, since the video input board 21 acquires an image at the time when the target S is changed to a position of −10 degrees, the start timing of the galvano controller 42 is synchronized with the image capture timing of the video input board 21. is there. That is, as shown in the graph of FIG. 8, the plot of the angular velocity of the eyeball E overlaps the point immediately before the angular velocity of the target S becomes −800 angles / second.

  Furthermore, after the target S is changed to a position of −10 degrees, the target S is fixed at that position, so that the angular velocity of the target S is 0 (zero) angle / second. In addition, from about 116.45 seconds to about 116.65 seconds of the measurement time, the change in the target S cannot be followed, and the angular velocity of the eyeball E remains at 0 (zero) angle / second. Thereafter, the eyeball E moves from the position of 10 degrees to the position of −10 degrees during the measurement time from about 116.65 seconds to about 116.73 seconds, so the angular velocity of the eyeball E is also 0 (zero). It varies between an angle / second and about -400 angles / second. Then, after about 116.73 seconds of the measurement time, the eyeball E follows the target S and is at the same −10 ° position, so the angular velocity of the eyeball E is also 0 (zero) angle / second.

  The analysis unit 23 can also measure the delay time from the application of the visual stimulus to the reaction of the eyeball E, also from the result of the graph shown in FIG. Specifically, the analysis unit 23 measures the point at which the angular velocity of the eyeball E starts to change from the measurement time of the angular velocity of the eyeball E plotted at the point immediately before the angular velocity of the target S becomes −800 angles / second. The time until time is measured as the delay time from when the visual stimulus is applied until the eyeball E reacts.

  Furthermore, the data interpolation unit 24 performs spline interpolation between samplings of angular velocity data (motion data) of the eyeball E when an image is acquired at a low sampling rate of 60 Hz. The angular velocity data of the eyeball E subjected to spline interpolation is close to the plot interval of the angular velocity data of the eyeball E when an image is acquired at a high sampling rate of 240 Hz, as in the plot (white square) of the graph shown in FIG. . For this reason, the spline-interpolated angular velocity data of the eyeball E has a plot interval equivalent to that obtained when an image is acquired at a high sampling rate of 240 Hz even during a period in which the change in the angular velocity of the eyeball E is large. Therefore, the computer 2 can measure the change in the angular velocity of the eyeball E finely by performing the spline interpolation on the angular velocity data of the eyeball E by the data interpolation unit 24, as in the case of acquiring an image at a high sampling rate.

  Furthermore, in the change in the position of the eyeball E detected by the balance function testing apparatus 100, the image capture timing for capturing the image and the start timing for starting the presentation of the target S or the change of the position are not synchronized. The case where they are synchronized will be described. FIG. 9 does not synchronize the image capture timing for capturing an image and the start timing for starting the presentation of the target S or the position change in the change in the position of the eyeball E detected by the balance function testing apparatus 100. It is a figure which shows an example. FIG. 10 synchronizes the image capture timing for capturing an image and the start timing for starting the presentation of the target S or the position change in the change in the position of the eyeball E detected by the balance function testing apparatus 100. It is a figure which shows an example.

  The graphs shown in FIG. 9 and FIG. 10 are the positions of the eyeball E from the 122.35 seconds to the 122.67 seconds of the measurement time, where the horizontal axis is time (seconds) and the vertical axis is the position (angle) of the eyeball E. The change in (angle) is plotted. The graphs shown in FIG. 9 and FIG. 10 are a plot (black square) when the video input board 21 acquires images at a high sampling rate of 240 Hz (the interval at which images are captured is short), and the video input board 21. Is a plot (white circle) when an image is acquired at a low sampling rate of 60 Hz (the interval at which the image is captured is long). Further, the graphs shown in FIGS. 9 and 10 also show the position (angle) of the target S (laser) with respect to the measurement time.

  In the graph shown in FIG. 9, the image capture timing and the start timing when the sampling rate of the video input board 21 is 60 Hz are not synchronized. Therefore, as shown in FIG. 9, a plot of the position of the eyeball E (white circle) at the point where the target S starts changing from the 0 degree position to the 15 degree position (about 122.38 seconds of the measurement time). Are not overlapping. However, when the sampling rate of the video input board 21 is 240 Hz, even if the image capture timing and the start timing are not synchronized, the interval between image captures is short, so the plot of the position of the eyeball E at the start point is plotted. (Black squares) overlap.

  On the other hand, in the graph shown in FIG. 10, the image capture timing and the start timing when the sampling rate of the video input board 21 is 60 Hz are synchronized. Therefore, as shown in FIG. 10, a plot (white circle) of the position of the eyeball E at the point where the target S starts changing from the 0 degree position to the 15 degree position (about 122.38 seconds of the measurement time). Are overlapping. Of course, even when the sampling rate of the video input board 21 is 240 Hz, the plot (black square) of the position of the eyeball E overlaps the starting point.

  FIG. 11 is a diagram showing a delay time from when a visual stimulus is applied to when the eyeball reacts at each position of the eyeball E. In the graph shown in FIG. 11, the delay time with respect to the position of the eyeball E from −30 degrees to 30 degrees is plotted with the horizontal axis representing the position (angle) of the eyeball E and the vertical axis representing the delay time (seconds). The graph shown in FIG. 11 shows a plot (black square) when the video input board 21 acquires an image at a high sampling rate of 240 Hz (the interval at which images are captured is short), and the video input board 21 is 60 Hz. A plot (white circle) is shown when an image is acquired at a low sampling rate (the interval at which images are captured is long) and synchronized with the start timing (hereinafter referred to as “synchronization timing”). Further, in the graph shown in FIG. 11, when the video input board 21 acquires an image at a low sampling rate of 60 Hz but is not synchronized with the start timing (asynchronous) (hereinafter referred to as “asynchronous timing”). The plot (X) is also shown.

  As can be seen from FIG. 11, a plot when the video input board 21 acquires an image at a low sampling rate of 60 Hz and a synchronous timing, and a plot when the video input board 21 acquires an image at a high sampling rate of 240 Hz. And almost overlap. For this reason, the balance function inspection apparatus 100 can be as accurate as the expensive video input board 21 and the imaging camera 1 that can acquire images at a high sampling rate even if the inexpensive video input board 21 and the imaging camera 1 are employed. Delay time can be measured. The plot when the video input board 21 acquires an image at a low sampling rate of 60 Hz and asynchronous timing is different from the plot when the video input board 21 acquires an image at a high sampling rate of 240 Hz. Is big.

  As described above, the balanced function inspection apparatus 100 according to the embodiment of the present invention provides the image capture timing (first timing) for capturing an image on the video input board 21 and the display or indication of the target S in the galvano controller 42. When synchronizing the start timing (second timing) for starting the change of position to measure the delay time until the eyeball reacts by giving a visual stimulus by the presentation of the target S or the change of the position The measurement start point can always be kept constant. Therefore, the balance function testing apparatus 100 according to the embodiment of the present invention moves slowly even when the target S moves rapidly in the balance function test in which visual stimulation is applied to the eyeball E to examine the reaction. Even in this case, it is possible to always accurately measure the delay time from when the visual stimulus is applied until the eyeball E reacts. Furthermore, the balance function inspection apparatus 100 according to the embodiment of the present invention provides visual stimulation even when the inexpensive imaging camera 1 and the video input board 21 having a long interval for capturing images are used until the eyeball E reacts. Since the delay time can always be accurately measured, an inexpensive apparatus can be provided.

  In addition, the balanced function inspection apparatus 100 according to the embodiment of the present invention uses the image capture signal of the video input board 21 to synchronize the start timing with the image capture timing, thereby separately providing a signal for synchronization. There is no need to generate, and there is no need to add another mechanism for signal generation. Since the imaging camera 1 and the video input board 21 do not need to input signals from the outside, the imaging camera 1 and the video input board 21 that are not provided with an external synchronization function may be used. As the image capture signal of the video input board 21, for example, a signal such as a horizontal or vertical synchronization signal of the imaging camera 1 can be used.

  Furthermore, the balance function inspection apparatus 100 according to the embodiment of the present invention can control the position of the visual target S with high accuracy by changing the position of the galvano mirror 41 with the galvano controller 42. The target presentation unit 4 is not limited to the configuration of the galvano mirror 41 and the galvano controller 42, and switches whether the target S is presented to the subject and changes the position of the target S. If possible, for example, the laser pointer 3 may be moved directly or moved.

  In addition, in the balanced function testing device 100 according to the embodiment of the present invention, the data interpolation unit 24 interpolates between the sampling of the movement data of the eyeball E, so that the inexpensive imaging camera 1 and video with a long interval for capturing an image. Even if the input board 21 is employed, it is possible to obtain a result equivalent to the movement data of the eyeball E acquired by the imaging camera 1 and the video input board 21 having a short interval for capturing images. In particular, the data interpolating unit 24 can obtain data equivalent to that having higher accuracy of the motion data of the eyeball E by interpolating between the sampling of motion data of the eyeball E by spline interpolation.

(Modification)
A modification of the balanced function testing apparatus 100 according to the embodiment of the present invention will be described below.

  (1) In the balanced function testing apparatus 100 shown in FIG. 1, the image capture signal of the video input board 21 is output to the AD board 22, and the start timing is synchronized with the image capture timing using the image capture signal. The configuration to be performed has been described. However, the present invention is not limited to this, and the balance function inspection apparatus is configured to output the start signal of the AD board 22 to the video input board 21 and synchronize the image capture timing with the start timing using the start signal. There may be.

  FIG. 12 is a schematic diagram showing a basic configuration of a balanced function testing apparatus according to the first modification of the present invention. The balance function testing apparatus 100a shown in FIG. 12 records the movement of the eyeball E, measures the nystagmus of the eyeball E, and measures the delay time from when the visual stimulus is applied until the eyeball E reacts. . The balance function testing apparatus 100a includes an imaging camera 1 configured with a CCD camera, a computer 2 configured with a personal computer, a laser pointer 3 that generates a target S for applying visual stimulation to the eyeball E, and a target S The target presentation part 4 which changes the position of is included. In the balanced function testing apparatus 100a shown in FIG. 12, the same components as those in the balanced function testing apparatus 100 shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will not be repeated.

  The computer 2 starts presenting or changing the position of the visual target S to the galvano controller 42 in order to capture from the video input board 21 the image of the eyeball E when the visual stimulus is given by the presentation or changing the position of the visual target S. The start signal (galvano control signal) to be output is output to the video input board 21. Then, the video input board 21 starts capturing an image from the imaging camera 1 based on the start signal. That is, as shown in FIG. 6, the video input board 21 makes the rising timing of the image capture signal coincide with the rising timing of the start signal output from the AD board 22. Thereby, the rising timing of the start signal and the rising timing with the image capture signal are synchronized.

  As described above, the balanced function testing apparatus 100a according to the first modification generates a separate signal for synchronization by synchronizing the image capture timing with the start timing using the start signal of the AD board 22. In addition, it is not necessary to add a separate mechanism for signal generation, and the measurement start point of the delay time until the eyeball E reacts by giving a visual stimulus by the presentation of the target S or changing the position is displayed for each visual stimulus. Can be unified.

  (2) The balanced function testing apparatus 100a shown in FIG. 12 outputs a start signal from the AD board 22 to the video input board 21 and uses the start signal to synchronize the image capture timing with the start timing. did. However, the present invention is not limited to this. In addition to the video input board 21 and the AD board 22, using the internal clock signal of the internal clock generator provided in the computer 2, The balance function inspection device may be configured to synchronize with each other.

  FIG. 13 is a schematic diagram showing a basic configuration of a balanced function testing apparatus according to Modification 2 of the present invention. The balance function testing apparatus 100b shown in FIG. 13 records the movement of the eyeball E, measures the nystagmus of the eyeball E, and measures the delay time from the application of the visual stimulus to the reaction of the eyeball E. . The balance function testing apparatus 100b includes an imaging camera 1 configured with a CCD camera, a computer 2 configured with a personal computer, a laser pointer 3 that generates a target S for applying visual stimulation to the eyeball E, and a target S The target presentation part 4 which changes the position of is included. Further, the computer 2 includes a video input board 21, an AD board 22, an analysis unit 23, a data interpolation unit 24, an adjustment time setting unit 25, and an internal clock generation unit 26. In the balanced function testing apparatus 100b shown in FIG. 13, the same components as those in the balanced function testing apparatus 100 shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will not be repeated.

  The internal clock generator 26 is a clock generator provided in the computer 2, and generates a clock signal used for processing in the computer 2. For example, the internal clock generation unit 26 generates an internal clock signal in order to synchronize communication within the computer 2 or to synchronize processing timings in a plurality of data processing units.

  The computer 2 captures the image of the eyeball E when the visual stimulus is given by the presentation of the target S or the change of the position from the video input board 21, so that the internal clock signal is sent to the internal clock generator 26 and the video input board 21. Output to the AD board 22. Then, the video input board 21 starts capturing an image from the imaging camera 1 based on the internal clock signal. In other words, the video input board 21 matches the rising timing of the image capture signal with the rising timing of the internal clock signal. On the other hand, the AD board 22 generates a start signal (galvano control signal) for causing the galvano controller 42 to start presenting the target S or changing the position based on the internal clock signal. That is, the AD board 22 generates a start signal whose rising timing coincides with the rising timing of the internal clock signal. Thereby, the rising timing of the start signal and the rising timing with the image capture signal are synchronized.

  As described above, the balanced function testing apparatus 100b according to the second modification example captures an image for capturing an image from the imaging camera 1 to the video input board 21 based on the internal clock signal generated by the internal clock generation unit 26. By generating a signal and a start signal for causing the galvano controller 42 to start presenting or changing the position of the target S, and synchronizing the start timing and the image capture timing, a separate signal for synchronization is not generated. The measurement start point of the delay time until the eyeball E reacts by giving the visual stimulus by the presentation of the target S or the change of the position can be unified for each visual stimulus. Furthermore, since the balanced function testing apparatus 100b according to the second modification uses the internal clock signal, it is easy to synchronize communication and processing with other components controlled by the computer 2.

  (3) In the balanced function testing apparatus 100b shown in FIG. 13, in addition to the video input board 21 and the AD board 22, using the internal clock signal of the internal clock generation unit provided in the computer 2, the start timing and image The configuration for synchronizing the capture timing has been described. However, the present invention is not limited to this, and it may be a balanced function inspection device configured to synchronize the start timing and the image capture timing using an external clock signal of an external clock generation unit provided outside the computer 2. Good.

  FIG. 14 is a schematic diagram showing a basic configuration of a balanced function testing apparatus according to Modification 3 of the present invention. The balance function testing apparatus 100c shown in FIG. 14 records the movement of the eyeball E, measures the nystagmus of the eyeball E, and measures the delay time from when the visual stimulus is applied until the eyeball E reacts. . The balance function inspection apparatus 100c includes an imaging camera 1 configured with a CCD camera, a computer 2 configured with a personal computer, a laser pointer 3 that generates a target S for applying visual stimulation to the eyeball E, and a target S. A target presentation unit 4 for changing the position and an external clock generation unit 6 are included. Further, the computer 2 includes a video input board 21, an AD board 22, an analysis unit 23, a data interpolation unit 24, and an adjustment time setting unit 25. In the balanced function testing apparatus 100c shown in FIG. 14, the same components as those in the balanced function testing apparatus 100 shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will not be repeated.

  The external clock generation unit 6 is a clock generation unit provided outside the computer 2, and is provided in, for example, an external device connected to the computer 2, and an external clock signal is used to synchronize with the processing in the external device. Is generated.

  The computer 2 captures an image of the eyeball E when the visual stimulus is given by presenting the target S or changing the position from the video input board 21, so that an external clock signal is received from the external clock generator 6 and the video input board 21. Input to the AD board 22. Then, the video input board 21 starts capturing an image from the imaging camera 1 based on the external clock signal. That is, the video input board 21 matches the rising timing of the image capture signal with the rising timing of the external clock signal. On the other hand, the AD board 22 generates a start signal (galvano control signal) for causing the galvano controller 42 to start presenting the target S or changing the position based on the external clock signal. That is, the AD board 22 generates a start signal whose rising timing coincides with the rising timing of the external clock signal. Thereby, the rising timing of the start signal and the rising timing with the image capture signal are synchronized.

  As described above, the balanced function testing apparatus 100 c according to the third modification example captures an image for capturing an image from the imaging camera 1 to the video input board 21 based on the external clock signal generated by the external clock generation unit 6. A signal and a start signal for causing the galvano controller 42 to start presenting or changing the position of the target S are generated, and by synchronizing the start timing and the image capture timing, viewing by changing the presentation or position of the target S It is possible to always obtain an image of the eyeball E when the stimulus is applied. Further, since the balanced function testing apparatus 100c according to the third modification uses the external clock signal, it is easy to synchronize with the processing in the external device connected to the computer 2.

  (4) In the balanced function test apparatus 100, 100a to 100c shown in the embodiment of the present invention and the first to third modifications, the computer 2 includes the adjustment time setting unit 25, but the adjustment time is particularly set. Explained when not. However, the present invention is not limited to this. For example, when there is a time difference from when the start signal is input to the galvano controller 42 until the position of the galvano mirror 41 is changed, the adjustment time setting unit 25 sets the adjustment time. It may be a balanced function inspection device configured as described above.

  FIG. 15 is a diagram for explaining the synchronization timing of the balanced function testing device according to the fourth modification of the present invention. Although not shown, the balanced function testing apparatus according to the modified example 4 has the same configuration as that of the balanced function testing apparatus 100 shown in FIG. 1, and the same components are denoted by the same reference numerals and detailed description thereof will not be repeated. .

  As shown in FIG. 15, the adjustment time setting unit 25 adjusts the time difference after the start signal is input to the galvano controller 42 until the position of the galvano mirror 41 is changed and the target presentation starts. Set as time. Specifically, the adjustment time is the time from the rising timing of the start signal to the timing at which the target presentation starts. In the graph shown in FIG. 15, the timing at which the position of the galvano mirror 41 is changed and the target presentation starts is schematically expressed as a step signal. However, the present invention is not limited to this, and the target presentation start timing. Can be any signal.

  The AD board 22 generates a start signal (galvano control signal) that causes the galvano controller 42 to start presenting or changing the position of the target S based on the timing when the image capture signal output from the video input board 21 is given. To do. However, if the AD board 22 only generates a start signal whose rising timing coincides with a certain rising timing of the image capture signal output from the video input board 21, the start of the target presentation is delayed by the adjustment time. An image of the eyeball E at the time when the visual stimulus is applied cannot be acquired.

  Therefore, the computer 2 according to the fourth modification delays the rise timing of the image capture signal output from the video input board 21 by the adjustment time set in the adjustment time setting unit 25 and synchronizes with the start signal timing. . As a result, as shown in FIG. 15, the rising timing of the image capture signal is synchronized with the rising timing of the start of target presentation, not the rising timing of the start signal. Therefore, the balanced function testing apparatus according to the fourth modification can always acquire an image of the eyeball E at the rising timing of the target presentation start, which is the time point when the visual stimulus is applied.

  The adjustment time setting unit 25 has been described as a configuration that delays the timing of applying an image capture signal to the video input board 21 by the adjustment time. However, the adjustment time setting unit 25 is configured to advance the start signal timing by the adjustment time relative to the AD board 22. But you can. That is, the adjustment time setting unit 25 only needs to be able to relatively delay the timing of giving the image capture signal and the timing of the start signal by the adjustment time.

  As described above, the balanced function inspection apparatus according to the fourth modification delays the image capture timing of the video input board 21 by the adjustment time set in the adjustment time setting unit 25 and synchronizes with the start timing of the galvanometer mirror 41. By doing so, it is possible to take into account the processing shift unique to the optotype presenting unit 4, and it is possible to always obtain an image of the eyeball when the visual stimulus is given by the presentation of the optotype S or the change of the position. The adjustment time setting unit 25 has the same configuration even if the adjustment time is set for each configuration of the target presentation unit 4 (for example, a configuration of the galvano mirror 41 and the galvano controller 42 or a configuration in which the laser pointer 3 is directly moved). However, an adjustment time may be set for each product.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 imaging camera, 2 computer, 3 laser pointer, 4 target presentation unit, 5 screen, 6 external clock generation unit, 21 video input board, 22 A / D board, 23 analysis unit, 24 data interpolation unit, 25 adjustment time setting Unit, 26 internal clock generation unit, 41 galvanometer mirror, 42 galvano controller.

Claims (9)

An equilibrium function test apparatus for acquiring eye movement data in a balance function test,
An imaging device for imaging eye movement;
An image capturing unit that captures images captured by the imaging device at predetermined intervals;
A target generating unit that generates a target for the subject to visually recognize;
Presenting the optotype generated by the optotype generating unit to the subject , and an optotype presenting unit for changing the position of the optotype,
A control unit that captures the image in the image capturing unit, presents the target or changes the position in the target presentation unit, and controls the position of the target;
The control unit synchronizes a first timing for capturing the image in the image capturing unit and a second timing for starting presentation or position change of the target in the target presentation unit. .   The control unit presents or changes the position of the visual target to the visual target presenting unit based on the timing at which an image capture signal for capturing the image from the imaging device is input to the image capture unit. The balanced function testing device according to claim 1, wherein a start signal to be started is generated to synchronize the second timing of the target presentation unit with the first timing of the image capturing unit.   The control unit causes the image capturing unit to start capturing the image based on a start signal that causes the target presenting unit to start presenting or changing the position of the target. The balanced function inspection apparatus according to claim 1, wherein the first timing of the image capturing unit is synchronized with the second timing of the target presentation unit.   The control unit, based on an internal clock signal generated internally, an image capture signal for capturing the image from the imaging device to the image capture unit, and presentation of the target to the target presentation unit or The balanced function testing device according to claim 1, wherein a start signal for starting a change of position is generated, and the first timing of the image capturing unit and the second timing of the target presentation unit are synchronized.   The control unit, based on an external clock signal input from the outside, the image capture signal for capturing the image from the imaging device to the image capture unit, and the presentation of the target to the target presentation unit or The balanced function testing device according to claim 1, wherein a start signal for starting a change of position is generated, and the first timing of the image capturing unit and the second timing of the target presentation unit are synchronized. The control unit includes an adjustment time setting unit that sets an adjustment time from when the start signal is input to the target presentation unit until presentation of the target or a change in position of the target starts. Including
The control unit delays the first timing of the image capturing unit by the adjustment time set in the adjustment time setting unit and synchronizes with the second timing of the target presentation unit. Item 6. The equilibrium function testing device according to any one of items 5. The target presentation unit
A reflection unit that reflects the target generated by the target generation unit;
A position changing unit that changes the position of the reflecting unit,
The said control part controls the presentation or position change of the said target in the said target presentation part by controlling the position of the said reflection part changed in the said position change part. The balanced function testing device according to any one of the above. The controller is
From the image captured in the image capturing unit, an analysis unit that analyzes the position of the eyeball,
The balance function test according to claim 1, further comprising: a data interpolation unit that interpolates between samplings of eye movement data in which the positions of the eyeballs analyzed by the analysis unit are arranged in time series. apparatus. 9. The balance function testing device according to claim 8, wherein the data interpolation unit interpolates between sampling of eye movement data by spline interpolation.

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