JP2019177045A - Visual target presentation device - Google Patents

Abstract

To provide a visual target presentation device that can effectively use a space needed for an eye examination and can accurately perform the eye examination.SOLUTION: A visual target presentation device 2 comprises: a housing 3; a near sight eye chart 42 for a near sight examination provided inside the housing 3; a visual target presentation optical system 5 for presenting a luminous flux emitted from the near sight eye chart 42 to a subject's eye E; a housing driving part 31 for moving at least a portion of the housing 3 along an optical axis LA2 of the visual target presentation optical system 5; a photographing part 61 comprising a first camera and a second camera for photographing the subject's eye E substantially at the same time from directions different from each other; and a control device 7 for identifying a position of the subject's eye E in a direction of the optical axis LA2 by analyzing a plurality of images taken substantially at the same time by the first camera and the second camera, and performing control for adjusting a distance between the near sight eye chart 42 and the subject's eye E to a predetermined presentation distance by controlling the housing driving part 31 on the basis of the position of the subject's eye E.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an optotype presenting apparatus that presents an optotype attached to an eye chart for optometry toward an eye to be examined.

  In the field of ophthalmology, as a visual acuity test for the subject's eye, a distance test is performed in a state where a target such as a Landolt ring attached to the visual chart is presented at a position about 5 m away from the eye to be examined. And a near-field examination performed in a state where the visual target is presented at a position about 30 cm to 50 cm away from the eye to be examined.

  When a distance inspection is performed, for example, an optotype presenting apparatus in which an optotype presenting optical system including a reflecting mirror, a half mirror, and a concave mirror is arranged in a housing is used. In such an optotype presenting apparatus, the light beam emitted from the distance inspection table arranged in the housing is reflected by the reflecting mirror toward the half mirror, passes through the half mirror, and is guided to the concave mirror. . The light beam reflected by the concave mirror is guided again to the half mirror, and is reflected toward the eye to be examined by the half mirror. The light beam reflected by the half mirror forms a virtual image at a position about 5 m away from the eye to be examined. Therefore, such a visual target presenting apparatus can be installed even in a place where it is difficult to secure a presentation distance of about 5 m. Thereby, the distance (working distance) between a to-be-examined eye and the front surface of an optotype presenting apparatus can be shortened, and the space required for optometry can be used effectively.

  On the other hand, when a near-field inspection is performed, for example, a near-field inspection table connected to the above-described subjective optometry means (refractor head) of the optotype presenting apparatus is used. That is, when a near-field inspection is performed, the near-point rod attached to the refractor head hangs down in front of the eye of the subject's eye, so that the near-inspection visual table held on the near-point rod becomes the eye to be examined. Presented towards The near-inspection visual chart is movable along the near-point bar at a position about 30 cm to 50 cm away from the eye to be examined.

  Therefore, in the optotype presenting apparatus as described above, the distance between the eye to be examined and the front face of the optotype presenting apparatus needs to be longer than the length of the near-point bar that holds the near-field inspection chart. is there. In general, the distance between the eye to be examined and the front surface of the optotype presenting apparatus is about 1 m. On the other hand, there is a desire to further reduce the distance between the eye to be examined and the front surface of the optotype presenting apparatus.

  In view of this, as a disposition of the far-field inspection visual chart, one approach is to install a near-field visual chart on the housing side of the visual target presenting device. According to this, near-eye optometry using a naked eye, a trial frame, or actual glasses can be performed without using a refractor head. However, in this case, the distance from the eye to the visual table changes due to the change in the position of the eye to be examined, which may affect the optometry accuracy. That is, in the distance test, since the presentation distance of the target is as long as about 5 m, the ratio of the change in the position of the eye to be examined with respect to the presentation distance is relatively low. Therefore, even if the position of the subject's eye changes due to the change in the position of the subject's neck or face, the optometry accuracy is hardly affected. On the other hand, in the near-field examination, the target distance of the target is about 30 cm or more and about 50 cm or less, so the ratio of the change in the position of the eye to be examined with respect to the presentation distance is relatively high. Therefore, when taking a near-field test, if the position of the subject's eye changes due to changes in the position of the subject's neck or face, an accurate test may not be performed.

  Patent Document 1 discloses a visual acuity table device that presents a visual target toward an eye to be examined. The visual acuity table device described in Patent Document 1 includes a slide mechanism section that slides the apparatus main body along the direction of the light beam, a driving unit that drives the slide mechanism section, and a distance between the apparatus main body and the subjective optometry means. And a distance sensor for measuring. The visual acuity table apparatus described in Patent Document 1 measures the distance between the apparatus main body and the subjective optometry means by a distance sensor, and drives the slide mechanism section by the driving means based on the measurement result of the distance sensor. The distance setting for the self-awareness of the device body is performed.

  However, in the visual acuity table device described in Patent Document 1, the specific means for measuring the distance between the device main body and the eye to be examined is unknown. Therefore, there is room for improvement in terms of performing an accurate inspection. In other words, when a subject undergoes an examination using a trial frame or actual glasses without using a refractor head, the position of the subject's eye changes as the subject's neck or face changes. There are things to do. In such a case, it is necessary to measure the distance between the apparatus main body and the eye to be examined, not the distance between the apparatus main body and the subjective optometry means. On the other hand, in the visual acuity table device described in Patent Document 1, the specific means for measuring the distance between the device main body and the eye to be examined is unknown. Therefore, there is room for improvement in terms of performing an accurate inspection.

JP 7-136112 A

  The present invention has been made to solve the above-described problem, and an object thereof is to provide an optotype presenting apparatus that can effectively use a space necessary for optometry and can perform accurate optometry. And

  According to the present invention, the subject is an optotype presenting apparatus that presents an optotype attached to an eye chart for optometry toward an eye to be examined. The optotype presenting apparatus is provided inside a housing and the housing. A near vision for a near examination and a light beam emitted from the near vision provided inside the housing to the eye to be examined via an optical system disposed inside the housing. Photographing the eye to be inspected substantially simultaneously from different directions with an optotype presenting optical system to be presented, a housing drive unit that moves at least a part of the housing along the optical axis of the optotype presenting optical system And a position of the eye to be examined in the direction of the optical axis by analyzing a plurality of images photographed substantially simultaneously by the first camera and the second camera. And the housing driving unit based on the position of the eye to be examined And a control device that executes control to adjust a distance between the near vision table and the eye to be examined to a predetermined presentation distance. .

  According to the above configuration, since the near vision for the near vision examination is provided inside the housing, the near vision is presented between the eye to be examined and the front of the optotype presenting apparatus during the near vision examination. Not. Therefore, it is not necessary to secure a space for presenting the near vision table between the eye to be examined and the front surface of the optotype presenting apparatus. Thereby, the distance (working distance) between a to-be-examined eye and the front surface of an optotype presenting apparatus can be shortened, and the space required for optometry can be used effectively.

  Further, the control device identifies the position of the eye to be examined in the direction of the optical axis by analyzing a plurality of images photographed substantially simultaneously by the first camera and the second camera, and based on the position of the eye to be examined. By controlling the body drive unit, control is performed to match the distance between the near vision table and the eye to be examined to a predetermined presentation distance. Therefore, even when the position of the subject's eye changes due to the change in the position of the subject's neck or face, the control device follows the optical axis of the optotype presenting optical system based on the position of the subject's eye. Then, at least a part of the housing is moved to adjust the distance between the near vision and the eye to be examined to a predetermined presentation distance. Therefore, the control device can cause the position of the near vision table to follow the change in the position of the eye to be examined in the direction of the optical axis of the optotype presenting optical system. That is, the control device can perform tracking of the near vision table for the movement of the eye to be examined by performing tracking of the housing with respect to the movement of the eye to be examined. As a result, a near vision is provided inside the housing, and an accurate near-field examination is performed even when the position of the subject's eye changes due to a change in the position of the subject's neck or face. be able to.

  Preferably, the photographing unit is a first photographing unit, and further includes a second photographing unit having a wider angle of view than the first photographing unit, and the second photographing unit includes at least one camera. And the feature point of the eye to be examined can be specified in a wider range than the first imaging unit.

  According to the said structure, a 1st imaging | photography part functions as a stereo camera for short distance imaging | photography. On the other hand, the second photographing unit functions as a camera for long-distance photographing. And a control apparatus specifies the feature point of a to-be-tested eye by analyzing the image image | photographed by the 2nd imaging | photography part for long distance imaging | photography first. According to this, even when the housing is disposed at a position relatively far from the eye to be examined, the second photographing unit can photograph the face of the subject more reliably. Feature points can be identified more reliably. When the control device specifies the feature point of the eye to be examined, the target is presented by analyzing a plurality of images taken substantially simultaneously by the first photographing unit (first camera and second camera) for short-distance photographing. The position of the eye to be examined in the direction of the optical axis of the optical system is specified. According to this, the control device can more reliably acquire the image of the eye to be examined using the second photographing unit for long-distance photographing and the first photographing unit for short-distance photographing. The position of the eye to be examined in the direction of the optical axis can be more reliably specified. As described above, according to the above configuration, even when the casing is arranged at a position relatively far from the eye to be examined at the start of the examination, the control device can detect the object in the direction of the optical axis of the optotype presenting optical system. The position of the optometry can be specified more reliably.

  Preferably, the second photographing unit includes a third camera and a fourth camera that photograph the eye to be examined from substantially different directions at the same time, and the control device includes the third camera and the fourth camera. Analyzing a plurality of images photographed substantially simultaneously by the first camera and the second camera after identifying the feature points of the eye to be examined by analyzing a plurality of images photographed substantially simultaneously. Thus, the position of the eye to be examined in the direction of the optical axis is specified.

  According to the said structure, the 2nd imaging | photography part functions as a stereo camera for short distance imaging | photography by using the at least 2 or more camera image | photographed from a different direction, and can obtain the information of a working distance direction.

  Preferably, the near vision is an electronic display device that displays the optotype based on a signal transmitted from the control device, and the control device is provided between the near vision and the eye to be examined. The size of the image of the target is controlled based on the distance, and the visual angle of the target is kept constant.

  According to the said structure, even if it is a case where the distance between a near vision table and a to-be-examined eye changes, the visual angle of a visual target is kept constant. Therefore, a more accurate near-field inspection can be performed.

  Preferably, the housing driving unit includes a stepping motor.

  According to the said structure, since the housing | casing drive part has a stepping motor, it can determine the position of a housing | casing with a higher precision.

  Preferably, the display device further includes a display unit that displays an image, and the control device performs control to display the distance between the near vision table and the eye to be examined on the display unit.

  According to the above configuration, the distance between the near vision table and the eye to be examined is displayed on the display unit. That is, the display distance of the target attached to the near vision is displayed on the display unit. Therefore, the examiner can confirm whether or not the distance between the near vision and the eye to be examined matches the predetermined presentation distance by using the display unit.

  Preferably, it further includes a distance visual table for distance inspection provided inside the housing, and a light beam emitted from the distance visual table is an optical system disposed inside the housing. And is presented to the eye to be examined by the optotype presenting optical system.

  According to the above configuration, the distance visual table and the near visual table are presented to the eye to be examined by the visual target presenting optical system via the optical system disposed inside the housing. Therefore, the optical path of the luminous flux emitted from the near vision is overlapped with a part of the luminous flux emitted from the distance vision. Thereby, size reduction of a housing | casing can be achieved and the space required for optometry can be utilized effectively.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to utilize effectively the space required for optometry, the optotype presentation apparatus which can perform an exact optometry can be provided.

It is a perspective view showing the optotype presenting apparatus concerning the embodiment of the present invention. It is a side view showing the optotype presenting apparatus concerning this embodiment. It is a top view showing the optotype presenting apparatus concerning this embodiment. It is a block diagram showing the principal part structure of the optotype presenting apparatus concerning this embodiment. It is a flowchart showing the 1st specific example of operation | movement of the optotype presenting apparatus which concerns on this embodiment. It is a flowchart showing the 2nd specific example of operation | movement of the optotype presenting apparatus which concerns on this embodiment. It is a flowchart showing the 2nd specific example of operation | movement of the optotype presenting apparatus which concerns on this embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
The embodiments described below are preferred specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless otherwise stated, the present invention is not limited to these embodiments. Moreover, in each drawing, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted suitably.

FIG. 1 is a perspective view showing an optotype presenting apparatus according to an embodiment of the present invention.
FIG. 2 is a side view showing the optotype presenting apparatus according to the present embodiment.
FIG. 3 is a top view illustrating the optotype presenting apparatus according to the present embodiment.
FIG. 4 is a block diagram showing a main configuration of the optotype presenting apparatus according to the present embodiment.
2 and 3, for convenience of explanation, the housing of the optotype presenting apparatus is represented by a broken line.

  The optotype presenting apparatus 2 according to the present embodiment is an apparatus that presents an optotype attached to a visual chart for optometry toward the eye E to be examined, and includes a housing 3, a near visual chart 42, and a visual target. The presenting optical system 5, the first photographing unit 61, the control device 7, and the housing driving unit 31 are provided. The optotype presenting apparatus 2 may further include an optometry table 9, a second imaging unit 62, and a distance visual table 41. The near vision 42, the target presentation optical system 5, the first imaging unit 61, the control device 7, the second imaging unit 62, and the far vision table 41 are provided inside the housing 3. ing.

  As shown in FIG. 1, the optometry table 9 includes a column 91, a subjective optometry means (refractor head) 92, and an illumination unit 93. The support column 91 is provided to be rotatable about an axis in the vertical direction Y. The subjective optometry means 92 and the illumination unit 93 are supported by the support column 91. The subjective optometry means 92 is attached to the housing 3 of the visual presentation device 2 and may be configured to be detachable with respect to the front of the eye to be examined.

  The housing 3 accommodates the near vision table 42, the far vision table 41, the optotype presenting optical system 5, the first imaging unit 61, the second imaging unit 62, and the control device 7 therein. And a window W provided at a position facing the subject J. The window W is formed of a translucent resin such as polyacrylate resin (PMMA) and has a thickness of about 2 mm. In the optotype presenting apparatus 2 according to the present embodiment, since the near vision table 42 is provided inside the housing 3, the corneal apex of the eye E of the subject J, the front surface of the housing 3, The distance (working distance) WD between the two can be set to be less than the near optometry distance. Details of this will be described later. Here, in the optotype presenting apparatus 2 according to the present embodiment, the front surface of the window W is an example of the front surface of the housing 3.

  The near vision table 42 is a near vision examination table, and presents a visual target to the eye E to be examined. For example, the near vision table 42 is disposed inside the housing 3 as an electronic display device such as a liquid crystal display device, and can display a visual target such as a Landolt ring on the display screen 421. However, the near vision table 42 is not limited to the liquid crystal display device, and may be another display device, and may be formed of a glass plate or paper on which a target pattern is drawn.

  The distance visual chart 41 is a distance visual chart, and presents a visual target to the eye E to be examined. For example, the distance visual table 41 is disposed inside the housing 3 as an electronic display device such as a liquid crystal display device, and can display a visual target such as a Landolt ring on the display screen 411. However, the distance visual table 41 is not limited to the liquid crystal display device, and may be another display device, and may be formed of a glass plate or paper on which a visual target pattern is drawn.

  The optotype presenting optical system 5 is provided inside the housing 3, and the light beam emitted from the distance visual table 41 and the near visual table 42 passes through the optical system disposed inside the housing 3 to be examined. Present to E. The optotype presenting optical system 5 includes a first reflection mirror 51, a convex lens system 52, and a second reflection mirror 53. The first reflecting mirror 51 reflects the light beam radiated from the distance visual table 41 toward the convex lens system 52. The convex lens system 52 refracts the light beam reflected by the first reflecting mirror 51 to form a virtual image. The display screen 411 of the far vision table 41 is disposed between the convex lens system 52 and the focal point 521 of the convex lens system 52. Further, the convex lens system 52 is not limited to one plano-convex lens shown in FIG. 2, and may have a plurality of lenses.

  When the distance examination is performed, the second reflection mirror 53 reflects the light beam transmitted through the convex lens system 52 toward the eye E to be examined, and the far-presentation position at a predetermined distance in front of the corneal apex of the eye E to be examined. A virtual image is presented at 531. At this time, for example, the near vision table 42 moves in response to the driving force transmitted from the near vision table drive unit 43 (see FIG. 4), and the outside of the optical path of the light beam emitted from the far vision table 41. Has been evacuated. The distance between the corneal apex of the eye E and the distance presentation position 531 is about 5 m. When the near vision table 42 is arranged outside the optical path of the light beam emitted from the far vision table 41, the near vision table drive unit 43 is not necessarily provided.

  When the near examination is performed, the second reflection mirror 53 reflects the light beam emitted from the near vision table 42 and presents it to the eye E to be examined. As shown in FIG. 2, the near vision table 42 is provided on the light exit side of the convex lens system 52. Therefore, the light beam radiated from the near vision table 42 is not reflected by the first reflecting mirror 51 or transmitted through the convex lens system 52. However, the configuration of the visual target presenting optical system 5 of the present embodiment is an example, and is not limited to this.

  The first imaging unit 61 is provided inside the housing 3 and images the eye E to be examined. The first imaging unit 61 is arranged on the side of the far vision 41 and the near vision 42 with respect to the eye E with respect to the eye E, and photographs the eye E via the second reflection mirror 53. It is configured to be possible. The first imaging unit 61 of the present embodiment corresponds to the “imaging unit” of the present invention. For example, when viewed along the direction of the optical axis LA1 (see FIG. 2) of the light beam reflected by the first reflecting mirror 51 and guided to the second reflecting mirror 53, the first photographing unit 61 is close to the convex lens system 52. It is provided between the visual table 42. The first imaging unit 61 includes a first camera 611 and a second camera 612, and can capture a two-dimensional image of the eye E. The two-dimensional image may be a moving image or a still image. The two-dimensional image may be a color image or a monochrome image. The first camera 611 and the second camera 612 image the eye E from substantially different directions substantially simultaneously.

  The second imaging unit 62 is provided inside the housing 3 and images the eye E to be examined. For example, when viewed along the direction (optical axis direction Z) of the optical axis LA2 (see FIG. 2) of the light beam reflected by the second reflecting mirror 53 and guided to the eye E, the second imaging unit 62 is It is provided on the side opposite to the window W as viewed from the reflection mirror 53 (the rear side of the reflection surface of the second reflection mirror 53). The second imaging unit 62 includes a third camera 621 and a fourth camera 622, and can capture a two-dimensional image of the eye E. The two-dimensional image may be a moving image or a still image. The two-dimensional image may be a color image or a monochrome image. The third camera 621 and the fourth camera 622 image the eye E substantially simultaneously from different directions.

  The angle of view of the second imaging unit 62 is wider than the angle of view of the first imaging unit 61. The second imaging unit 62 has at least one camera, and can obtain information on the working distance direction as in the first imaging unit by using at least two cameras that capture images from different directions. Further, the second imaging unit 62 can specify the feature point E0 of the eye E in a wider range than the first imaging unit 61. That is, the field angles of the third camera 621 and the fourth camera 622 are wider than the field angles of the first camera 611 and the second camera 612, respectively. Therefore, the focal lengths of the third camera 621 and the fourth camera 622 are shorter than the focal lengths of the first camera 611 and the second camera 612, respectively. Further, each of the third camera 621 and the fourth camera 622 can capture a wider range than each of the first camera 611 and the second camera 612. Moreover, although the detection sensitivity deteriorates by reducing the expected angle of the second imaging unit relative to the second imaging unit, the detection range can be increased.

  The first camera 611, the second camera 612, the third camera 621, and the fourth camera 622 may be infrared cameras having sensitivity to infrared rays. When the first camera 611, the second camera 612, the third camera 621, and the fourth camera 622 are infrared cameras, the first photographing unit 61 and the second photographing unit 62 are infrared illuminations provided in the housing 3. The eye E is illuminated with infrared rays from 64 and an image of the eye E is taken with infrared rays reflected by the eye E. According to this, the 1st imaging | photography part 61 and the 2nd imaging | photography part 62 can image | photograph the infrared image of the eye E without making the subject J conscious of illumination. The infrared illumination 64 may be attached to the surface of the subjective optometry means 92 that faces the eye E to be examined.

  As illustrated in FIG. 4, the control device 7 includes a calculation unit 71, a storage unit 72, and an image processing unit 73. The calculation unit 71 is, for example, a CPU (Central Processing Unit) and the like, and executes program activation, signal control processing, calculation, drive control of each drive unit, and the like. That is, the calculation unit 71 performs overall control of the optotype presenting apparatus 2. The storage unit 72 stores, for example, a sequence program for adjusting the distance between the near vision 42 and the eye E to a predetermined presentation distance, a sequence program for image processing, an arithmetic program, and the like. ing. As the memory | storage part 72, the semiconductor memory etc. which were incorporated in the housing | casing 3 are mentioned, for example. Alternatively, the storage unit 72 may be a CD (Compact Disc), a DVD (Digital Versatile Disc), a RAM (Random access memory), a ROM (Read only memory), a hard disk, a memory card, or the like that can be connected to the target presentation device 2. Various storage media are listed.

  The image processing unit 73 includes an image analysis unit 74 and an image determination unit 731, and executes various types of image processing and image analysis on images captured by the first imaging unit 61 and the second imaging unit 62. To do. The image analysis unit 74 includes a feature point specifying unit 741 and a feature point position calculation unit 742, and analyzes the image of the eye E taken by the first imaging unit 61 and the second imaging unit 62. The position of the eye E is specified. The “position of the eye E” refers to the position of the eye E in the horizontal direction X (see FIG. 1), the position of the eye E in the vertical direction Y (see FIG. 1), and the position of the eye E in the optical axis direction Z. Including at least one of the positions.

  The feature point specifying unit 741 corresponds to the feature point E0 of the eye E in the image of the eye E by analyzing the image of the eye E taken by the first photographing unit 61 and the second photographing unit 62. Identify the location. As described above, examples of the feature point E0 of the eye E include the corneal apex, the pupil center, the pupil contour, the iris center, and the iris contour. Specifically, the feature point specifying unit 741 is based on the distribution of pixel values including the luminance value of the image of the eye E taken by the first image taking unit 61 and the second image taking unit 62, and the like. A position corresponding to the feature point E0 in the image is specified.

  Alternatively, the feature point specifying unit 741 first analyzes the image of the eye E taken by the second image taking unit 62, thereby determining a position corresponding to the feature point E0 of the eye E in the image of the eye E. You may specify. After that, the feature point specifying unit 741 analyzes the image of the eye E taken by the first image taking unit 61 to specify the position corresponding to the feature point E0 of the eye E in the image of the eye E. May be. For example, the feature point specifying unit 741 corresponds to the feature point E0 of the eye E based on the entire image of the face of the subject J taken by the third camera 621 and the fourth camera 622 having a relatively wide angle of view. And then, the feature point E0 of the eye E based on the image of the vicinity of the eye E of the subject J taken by the first camera 611 and the second camera 612 having a relatively narrow angle of view. A position corresponding to may be specified. According to this, the feature point specifying unit 741 can specify the position corresponding to the feature point E0 of the eye E more reliably.

  The feature point position calculation unit 742 calculates the position of the corneal vertex of the eye E based on the position corresponding to the feature point E0 of the eye E specified by the feature point specification unit 741. For the position of the corneal apex of the eye E in the horizontal direction X and the vertical direction Y, the feature point position calculation unit 742 has a feature point E0 in the image taken by at least one of the first camera 611 and the second camera 612. It can be calculated as substantially matching the position corresponding to (for example, the pupil center). Alternatively, for the position of the corneal apex of the eye E in the horizontal direction X and the vertical direction Y, the feature point position calculation unit 742 is a feature in the image captured by at least one of the third camera 621 and the fourth camera 622. It can be calculated as substantially matching the position corresponding to the point E0 (for example, the pupil center).

  Regarding the position of the corneal apex of the eye E in the optical axis direction Z, the feature point position calculation unit 742 includes the positions of the first camera 611 and the second camera 612 and the eye E to be examined specified by the feature point specification unit 741. Calculation is performed based on the position (for example, pupil position) corresponding to the feature point E0 in the plurality of images. That is, the feature point position calculation unit 742 performs the first camera 611 and the second camera 612 with respect to the positions of the first camera 611 and the second camera 612 and the positions corresponding to the pupils in the plurality of images of the eye E. Calculation is performed by applying a known trigonometric method considering the arrangement relationship of the camera 612, and a position shifted by a certain amount is set as a corneal apex.

  Alternatively, for the position of the corneal apex of the eye E in the optical axis direction Z, the feature point position calculation unit 742 includes the positions of the third camera 621 and the fourth camera 622 and the eye to be examined specified by the feature point specification unit 741. E is calculated based on a position (for example, pupil position) corresponding to the feature point E0 in the plurality of images. That is, the feature point position calculation unit 742 performs the third camera 621 and the fourth camera 421 with respect to the positions of the third camera 621 and the fourth camera 622 and the positions corresponding to the pupils in the plurality of images of the eye E. Calculation is performed by applying a known trigonometric method considering the arrangement relationship of the camera 622, and a position shifted by a certain amount is set as a corneal apex.

  The image determination unit 731 analyzes the images of the eye E taken by the first photographing unit 61 and the second photographing unit 62, so that the image of the eye E is converted into the first photographing unit 61 and the second photographing unit. It is determined whether or not it is included in a predetermined area in the two-dimensional image photographed by each of 62. The predetermined area is set in advance within the imaging range of each of the first imaging unit 61 and the second imaging unit 62, and is set as an area including the center of the imaging range, for example. The range of the predetermined area can be changed according to the shooting conditions such as the positions of the first shooting unit 61 and the second shooting unit 62 and the shooting magnification. The image determination unit 731 compares the coordinates corresponding to the predetermined area with the coordinates of the position corresponding to the feature point E0 of the eye E specified by the feature point specifying unit 741, thereby making the feature point of the eye E to be examined. It is determined whether or not a position corresponding to E0 is included in the predetermined area. When the feature point E0 is the pupil center, the positions of the corneal apex in the horizontal direction X and the vertical direction Y substantially coincide with the pupil center position, and the position of the corneal apex in the optical axis direction Z is a position 3 mm before the pupil center. Is approximately the same. As described above, setting a position that is shifted by a certain amount in the Z direction from the center of the pupil as the apex of the cornea actually has little influence on the optometry distance although there are individual differences.

  The housing drive unit 31 is provided in the housing 3, and includes a wheel, an actuator such as a motor that generates a driving force of the wheel, a transmission member such as a gear and a belt that transmits the driving force generated by the actuator to the wheel, Have The housing driving unit 31 moves at least a part of the housing 3 along the optical axis direction Z based on the signal transmitted from the control device 7. For example, the housing driving unit 31 has a stepping motor. When the housing driving unit 31 includes a stepping motor, the housing driving unit 31 can determine the position of the housing 3 with higher accuracy by controlling the number of pulses for driving the stepping motor.

  The housing drive unit 31 does not necessarily have an actuator such as a motor. For example, a wheel, a handle for manual operation, and a gear or belt that transmits a driving force generated by the operation of the handle to the wheel. And the like. According to this, the examiner can manually move at least a part of the housing 3 along the optical axis direction Z by operating the handle. In this case, the rotary encoder is preferably provided in the vicinity of the wheel. According to this, the control device 7 can calculate the moving distance of the housing 3 based on the signal regarding the rotation angle of the wheel or axle transmitted from the rotary encoder and the diameter of the wheel.

  As shown in FIG. 4, a first imaging drive unit 613, a second imaging drive unit 623, and a second reflection mirror drive unit 54 are further provided inside the housing 3. The first imaging drive unit 613 changes the positions and angles of the first camera 611 and the second camera 612 based on the signal transmitted from the control device 7. The second imaging drive unit 623 changes the positions and angles of the third camera 621 and the fourth camera 622 based on the signal transmitted from the control device 7. Based on the signal transmitted from the control device 7, the second reflecting mirror driving unit 54 rotates the second reflecting mirror 53 around the horizontal direction X axis or performs the second reflection around the vertical Y axis. The mirror 53 is rotated. That is, the second reflection mirror driving unit 54 changes the inclination angle of the reflection surface of the second reflection mirror 53 with respect to the horizontal plane, or changes the inclination angle of the reflection surface of the second reflection mirror 53 with respect to the vertical surface. Note that the second reflection mirror driving unit 54 is not necessarily provided. For example, each of the first imaging drive unit 613, the second imaging drive unit 623, and the second reflection mirror drive unit 54 includes an actuator such as a motor and a transmission member such as a gear and a belt.

  As shown in FIG. 4, the optotype presenting apparatus 2 according to the present embodiment may further include a user interface 8. The user interface 8 includes an operation unit 81, a display unit 82, and a notification unit 83. The operation unit 81 includes various buttons and keys provided outside the housing 3 and transmits signals related to the contents operated on the various buttons and keys to the control device 7. The display unit 82 includes a liquid crystal display device and the like, and can display an image of the eye E to be imaged by the first imaging unit 61 and the second imaging unit 62. The operation unit 81 and the display unit 82 may not be provided as separate devices, and may be a device in which an operation function and a display function are integrated, such as a touch panel. The notification unit 83 performs notification by sound or light based on the signal transmitted from the control device 7. Examples of the notification unit 83 include a speaker and a light emitting diode (LED).

  Here, when the near vision is provided inside the housing of the optotype presenting apparatus, the distance between the eye to be examined and the front surface of the housing can be set shorter, and the refractor head is not used. In both cases, it is possible to perform a near-field inspection using a trial frame, actual glasses, or the naked eye. On the other hand, a change in the position of the eye to be examined changes the distance from the eye to be examined to the visual table, which may affect the optometry accuracy. That is, in the distance test, since the presentation distance of the target is as long as about 5 m, the ratio of the change in the position of the eye to be examined with respect to the presentation distance is relatively low. Therefore, even if the position of the subject's eye changes due to the change in the position of the subject's neck or face, the optometry accuracy is hardly affected. On the other hand, in the near-field examination, the target distance of the target is about 30 cm or more and about 50 cm or less, so the ratio of the change in the position of the eye to be examined with respect to the presentation distance is relatively high. Therefore, when taking a near-field test, if the position of the subject's eye changes due to changes in the position of the subject's neck or face, an accurate test may not be performed.

  On the other hand, in the optotype presenting apparatus 2 according to the present embodiment, the control device 7 analyzes the plurality of images captured substantially simultaneously by the first camera 611 and the second camera 612 to thereby change the optical axis direction. By specifying the position of the eye E in Z and controlling the housing drive unit 31 based on the position of the eye E, the distance between the near vision 42 and the eye E is set to a predetermined presentation distance. Execute matching control.

  According to the optotype presenting apparatus 2 according to the present embodiment, even if the position of the eye E changes due to the change in the position of the neck or face of the subject J, the control device 7 can control the eye to be examined. Based on the position of E, at least a part of the housing 3 is moved along the optical axis direction Z, and the distance between the near vision table 42 and the eye E to be examined is adjusted to a predetermined presentation distance. Therefore, the control device 7 can cause the position of the near vision table 42 to follow the change in the position of the eye E in the optical axis direction Z. That is, the control device 7 can perform tracking of the near vision table 42 with respect to the movement of the eye E by performing tracking of the housing 3 with respect to the movement of the eye E. As a result, the near vision 42 is provided inside the housing 3, and even if the position of the eye E changes due to the change in the position of the neck or face of the subject J, an accurate Can be inspected.

  Further, since the near vision table 42 is provided inside the housing 3, it is not presented between the eye E to be examined and the front surface of the housing 3 during the near vision examination. Therefore, it is not necessary to secure a space for presenting the near vision table 42 between the eye E and the front surface of the housing 3. Thereby, the distance WD between the eye E to be examined and the front surface of the housing 3 can be shortened, and the space L0 (see FIG. 2) necessary for optometry can be shortened and the space can be saved.

  In addition, the control device 7 executes control to display the distance between the near vision 42 and the eye E on the display unit 82. That is, the display distance of the visual target attached to the near vision table 42 is displayed on the display unit 82. According to this, the examiner can confirm whether or not the distance between the near vision table 42 and the eye E to be examined matches the predetermined presentation distance by the display unit 82.

  Furthermore, when the first camera 611, the second camera 612, the third camera 621, and the fourth camera 622 are infrared cameras, the image analysis unit 74 does not make the subject J aware of the illumination, By analyzing the image of the eye E taken by the infrared camera, the position of the eye E can be specified. Further, even when the optotype presenting apparatus 2 is installed in a relatively dark place such as a dark room, the image analysis unit 74 analyzes the image of the eye E taken by the infrared camera, thereby causing the eye E to be examined. Can be specified.

Next, a specific example of the operation of the optotype presenting apparatus according to the present embodiment will be described with reference to the drawings.
FIG. 5 is a flowchart illustrating a first specific example of the operation of the optotype presenting apparatus according to the present embodiment.

  First, in step S <b> 11, when the optometry is started, the control device 7 starts photographing the eye E with the first camera 611 and the second camera 612. In the operation example of the flowchart shown in FIG. 5, the photographing of the eye E is moving image photographing. The first camera 611 and the second camera 612 perform moving image shooting at a predetermined frame rate. The shooting timings of the first camera 611 and the second camera 612 may be synchronized by the control device 7. The first camera 611 and the second camera 612 sequentially transmit the acquired frames to the control device 7. The control device 7 associates the frames transmitted from the first camera 611 and the second camera 612 according to the shooting timing. That is, the control device 7 associates the frames acquired by the first camera 611 and the second camera 612 substantially simultaneously. This association is executed based on the input timing of the frames transmitted from the first camera 611 and the second camera 612, for example.

  Subsequently, in step S12, the feature point specifying unit 741 of the image analysis unit 74 analyzes each frame transmitted from the first camera 611 and the second camera 612, and thereby the feature point of the eye E to be examined in each frame. A process for specifying a position corresponding to E0 is executed. Note that before the feature point specifying unit 741 executes the process of specifying the position corresponding to the feature point E0 of the eye E, a process of correcting the distortion of each frame may be executed.

  Subsequently, in step S13, the control device 7 determines whether or not the feature point specifying unit 741 has succeeded in specifying a position corresponding to the feature point E0 of the eye E. When the feature point specifying unit 741 fails to specify the position corresponding to the feature point E0 of the eye E (step S13: NO), the control device 7 asks the examiner the face of the subject J (the subject An instruction is made to arrange the optometry) within a prescribed range (step S14). Based on this, the examiner adjusts the position and height of the subject J's chair and the visual table presentation device 2. And the feature point specific | specification part 741 performs the process mentioned above regarding step S12.

  On the other hand, when the feature point specifying unit 741 succeeds in specifying the position corresponding to the feature point E0 of the eye E (step S13: YES), the image determination unit 731 corresponds to the eye E in step S15. It is determined whether the image to be included is included in a predetermined area of the frame. When the image corresponding to the eye E is not included in the predetermined area of the frame (step S15: NO), the control device 7 executes the process described above with respect to step S14. On the other hand, when an image corresponding to the eye E is included in a predetermined area of the frame (step S15: YS), in step S16, the feature point position calculation unit 742 of the image analysis unit 74 calculates the feature points. The position of the corneal apex of the eye E is calculated based on the position corresponding to the feature point E0 of the eye E specified by the specifying unit 741.

  That is, in step S16, the feature point position calculation unit 742 analyzes a plurality of images taken substantially simultaneously by the first camera 611 and the second camera 612, thereby analyzing the optical axis direction Z (optical axis LA2 (FIG. 2)). The position of the corneal apex of the eye E in the direction (see) is calculated. Specifically, the feature point position calculation unit 742 corresponds to the positions of the first camera 611 and the second camera 612 and the feature point E0 in the plurality of images of the eye E specified by the feature point specification unit 741. Based on the position (for example, pupil position), the position of the corneal apex of the eye E in the optical axis direction Z is calculated. In other words, the feature point position calculation unit 742 calculates the position of the corneal apex of the eye E in the optical axis direction Z based on the parallax between the two images obtained from the positions of the first camera 611 and the second camera 612.

  Subsequently, in step S <b> 17, the control device 7 controls the housing driving unit 31 based on the position of the corneal apex of the eye E calculated by the feature point position calculating unit 742, whereby the near vision table 42. The distance (optical path length) between the eye and the corneal apex of the eye E is adjusted to a predetermined presentation distance.

  Note that the control device 7 controls the notification unit 83 to adjust the distance (optical path length) between the near vision 42 and the corneal apex of the eye E to be examined by voice or light by controlling the notification unit 83. Notification may be executed. According to this, for example, the examiner and the subject J can easily adjust the distance between the near vision 42 and the corneal apex of the eye E to a predetermined presentation distance, It is possible to confirm whether or not the distance between the table 42 and the corneal apex of the eye E matches a predetermined presentation distance.

  Subsequently, in step S18, the control device 7 determines whether or not the position of the housing 3 has converged. When the position of the housing 3 has not converged (step S18: NO), the control device 7 executes the process described above with respect to step S16. On the other hand, when the position of the housing 3 has converged (step S18: YES), in step S19, the control device 7 is based on the distance between the near vision 42 and the corneal apex of the eye E to be examined. The size of the target image is controlled to keep the visual angle of the target constant. In this case, the near vision table 42 is an electronic display device such as a liquid crystal display device. Examples of the “size of the target image” include the image height of a target such as a Landolt ring.

  Thereby, the operation example of the optotype presenting apparatus 2 illustrated in FIG. 5 ends. In addition, the control apparatus 7 performs tracking of the housing | casing 3 with respect to the motion of the to-be-tested eye E, and tracking of the near vision table 42 with respect to the motion of the to-be-tested eye E by repeating the process of step S11-step S18. be able to.

  According to this specific example, the control device 7 follows the change in the position of the feature point E0 of the eye E in the optical axis direction Z (the direction of the optical axis LA2 (see FIG. 2)). Can be made. As a result, the near vision 42 is provided inside the housing 3, and even if the position of the eye E changes due to the change in the position of the neck or face of the subject J, an accurate Can be inspected. Even when the distance between the near vision 42 and the feature point E0 of the eye E changes, the visual angle of the visual target is kept constant. Thereby, a more accurate near-field inspection can be performed.

6 and 7 are flowcharts illustrating a second specific example of the operation of the optotype presenting apparatus according to the present embodiment.
First, in step S <b> 21, when the optometry is started, the control device 7 starts photographing the eye E with the third camera 621 and the fourth camera 622. In the operation example of the flowchart illustrated in FIG. 6, the photographing of the eye E is moving image photographing. The third camera 621 and the fourth camera 622 perform moving image shooting at a predetermined frame rate. Shooting timings by the third camera 621 and the fourth camera 622 may be synchronized by the control device 7. The third camera 621 and the fourth camera 622 sequentially transmit the acquired frames to the control device 7. The control device 7 associates the frames transmitted from the third camera 621 and the fourth camera 622 according to the shooting timing. That is, the control device 7 associates the frames acquired by the third camera 621 and the fourth camera 622 substantially simultaneously. This association is executed based on the input timing of the frames transmitted from the second camera 621 and the fourth camera 622, for example.

  As described above with reference to FIGS. 1 to 4, the field angles of the third camera 621 and the fourth camera 622 are wider than the field angles of the first camera 611 and the second camera 612, respectively. Therefore, the second imaging unit 62 can capture a wider range than the first imaging unit 61. For example, the second imaging unit 62 can image the entire range of the face wider than the eye E to be examined. As described above, in this specific example, the second imaging unit 62 functions as a stereo camera for long-distance shooting.

  Subsequently, in step S22, the feature point specifying unit 741 of the image analysis unit 74 analyzes each frame transmitted from the third camera 621 and the fourth camera 622, so that the feature point of the eye E in each frame is analyzed. A process for specifying a position corresponding to E0 is executed. Note that before the feature point specifying unit 741 executes the process of specifying the position corresponding to the feature point E0 of the eye E, a process of correcting the distortion of each frame may be executed.

  Subsequently, in step S23, the control device 7 determines whether or not the feature point specifying unit 741 has succeeded in specifying a position corresponding to the feature point E0 of the eye E. When the feature point specifying unit 741 fails to specify the position corresponding to the feature point E0 of the eye E (step S23: NO), the control device 7 makes the face of the subject J (the subject) to the examiner. An instruction is made to arrange the optometry) within a prescribed range (step S24). Based on this, the examiner adjusts the position and height of the subject J's chair and the visual table presentation device 2. And the feature point specific | specification part 741 performs the process mentioned above regarding step S22.

  On the other hand, when the feature point specifying unit 741 succeeds in specifying the position corresponding to the feature point E0 of the eye E (step S23: YES), the image determination unit 731 corresponds to the eye E in step S25. It is determined whether the image to be included is included in a predetermined area of the frame. When the image corresponding to the eye E is not included in the predetermined area of the frame (step S25: NO), the control device 7 executes the process described above with respect to step S24. On the other hand, when an image corresponding to the eye E is included in a predetermined region of the frame (step S25: YS), the control device 7 uses the first camera 611 and the second camera 612 in step S26. Imaging of the eye E is started.

  The field angles of the first camera 611 and the second camera 612 are narrower than the field angles of the third camera 621 and the fourth camera 622, respectively. Therefore, the first photographing unit 61 can photograph a narrow range compared to the second photographing unit 62. For example, the first imaging unit 62 can image a range in the vicinity of the eye E that is narrower than the entire face. Thus, in this specific example, the first photographing unit 61 functions as a stereo camera for short-distance photographing.

  Subsequently, the processing of step S26 to step S35 is the same as the processing of step S11 to step S19 described above with reference to FIG.

  According to this specific example, the first photographing unit 61 functions as a stereo camera for short-distance photographing. On the other hand, the second imaging unit 62 functions as a stereo camera for long-distance shooting. The feature point specifying unit 741 first analyzes the plurality of images captured substantially simultaneously by the second imaging unit 62 (the third camera 621 and the fourth camera 622) for long-distance imaging, thereby analyzing the eye to be examined. A feature point E0 of E is specified. According to this, even when the housing 3 is arranged at a position relatively far from the eye E, the second imaging unit 62 can more reliably image the face of the subject J. Thus, the feature point E0 of the eye E can be identified more reliably. When the feature point identifying unit 741 identifies the feature point E0 of the eye E, a plurality of images photographed substantially simultaneously by the first photographing unit 61 (first camera 611 and second camera 612) for short-distance photographing. To identify the feature point E0 of the eye E to be examined. Then, the feature point position calculation unit 742 calculates the position of the corneal vertex of the eye E based on the position corresponding to the feature point E0 of the eye E specified by the feature point specification unit 741.

  According to this, the control device 7 more reliably acquires an image of the feature point E0 of the eye E using the second imaging unit 62 for long-distance imaging and the first imaging unit 61 for short-distance imaging. The position of the corneal apex of the eye E in the optical axis direction Z can be calculated more reliably. As described above, according to this example, even when the housing 3 is disposed at a position relatively far from the eye E at the start of the examination, the control device 7 allows the eye E to be examined in the optical axis direction Z. The position of the corneal apex can be calculated more reliably. Further, the same effect as described above with reference to FIG. 5 can be obtained.

  In the operation examples shown in FIGS. 5 to 7, when the near examination is performed, the control device 7 controls the housing driving unit 31 based on the position of the corneal apex of the eye E to be examined. An example of control for adjusting the distance between the visual table 42 and the corneal apex of the eye E to be examined to a predetermined presentation distance has been described. However, the control device 7 controls the housing driving unit 31 based on the position of the corneal apex of the eye E to perform a distance test when the distance test is performed. The distance (optical path length) between the corneal apex of the optometry E may be set to a predetermined presentation distance.

  The embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the claims. A part of the configuration of the above embodiment can be omitted, or can be arbitrarily combined so as to be different from the above.

2 ... optotype presenting device, 3 ... housing, 5 ... optotype presenting optical system, 7 ... control device, 8 ... user interface, 9 ... optometry table, 31 ... -Housing drive unit, 41 ... Distance vision table, 42 ... Near vision table, 43 ... Near vision table drive unit, 51 ... First reflection mirror, 52 ... Convex lens system 53 ... 2nd reflection mirror, 54 ... 2nd reflection mirror drive part, 61 ... 1st imaging | photography part, 62 ... 2nd imaging | photography part, 64 ... Infrared illumination, 71 ... Calculation unit 72... Storage unit 73... Image processing unit 74... Image analysis unit 81... Operation unit 82. Support column, 92 ... subjective optometry means, 93 ... lighting unit, 411, 421 ... display screen, 521 ... focus, 531・ Distance presentation position, 611... First camera, 612... Second camera, 613... First imaging drive unit, 621... Third camera, 622. .. second imaging drive unit, 731... Image determination unit, 741... Feature point specifying unit, 742... Feature point position calculation unit, E .. eye to be examined, E0.・ ・ ・ Subject, L0 ... Space, LA1, LA2 ... Optical axis, W ... Window, WD ... Distance, X ... Horizontal direction, Y ... Vertical direction, Z ..Optical axis direction

Claims (7)

An optotype presenting apparatus for presenting an optotype attached to an eye chart for optometry toward an eye to be examined,
A housing,
A near vision for a near examination provided in the housing;
An optotype presenting optical system that presents the luminous flux provided from the near vision in the interior of the housing to the eye to be examined via the optical system disposed in the interior of the housing;
A housing driving unit that moves at least a part of the housing along the optical axis of the visual target presenting optical system;
An imaging unit having a first camera and a second camera for imaging the eye to be examined substantially simultaneously from different directions;
By analyzing a plurality of images taken substantially simultaneously by the first camera and the second camera, the position of the eye to be examined in the direction of the optical axis is specified, and the position of the eye to be examined is based on the position of the eye to be examined. A control device that performs control to adjust a distance between the near vision and the eye to be examined to a predetermined presentation distance by controlling a housing driving unit;
An optotype presenting apparatus characterized by comprising: The photographing unit is a first photographing unit,
A second photographing unit having a wider angle of view than the first photographing unit;
The target presentation device according to claim 1, wherein the second imaging unit includes at least one camera and is capable of specifying a feature point of the eye to be examined in a wider range than the first imaging unit. . The second imaging unit includes a third camera and a fourth camera that capture the eye to be examined substantially simultaneously from different directions,
The control device identifies the feature point of the eye to be examined by analyzing a plurality of images captured substantially simultaneously by the third camera and the fourth camera, and then controls the first camera and the second camera. The target presentation device according to claim 2, wherein the position of the eye to be examined in the direction of the optical axis is specified by analyzing a plurality of images photographed substantially simultaneously by a camera. The near vision is an electronic display device that displays the visual target based on a signal transmitted from the control device,
The control device controls the size of the image of the target based on the distance between the near vision table and the eye to be examined, and keeps the visual angle of the target constant. The optotype presenting apparatus according to any one of claims 1 to 3.   The visual target presentation device according to claim 1, wherein the housing driving unit includes a stepping motor. A display unit for displaying an image;
The visual control according to any one of claims 1 to 5, wherein the control device executes control to display the distance between the near vision and the eye to be examined on the display unit. Sign presentation device. Further comprising a distance visual table for distance inspection provided inside the housing;
The light beam emitted from the far vision is presented to the eye to be examined by the optotype presenting optical system via an optical system arranged inside the housing. The optotype presenting apparatus according to any one of 6.

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