JP6869074B2 - Ophthalmic equipment - Google Patents

Description

The present invention relates to an ophthalmic apparatus for acquiring data of an eye to be inspected.

The ophthalmologic apparatus includes an ophthalmologic imaging apparatus for obtaining an image of the eye to be inspected and an ophthalmologic measuring apparatus for measuring the characteristics of the eye to be inspected.

Examples of ophthalmologic imaging devices include an optical coherence tomography that obtains a tomographic image using optical coherence tomography (OCT), a fundus camera that photographs the fundus, and a fundus image by laser scanning using a confocal optical system. There are scanning laser ophthalmoscopes (SLO) and the like.

In addition, as an example of an ophthalmic measuring device, an ophthalmic refraction tester (refractometer, keratometer) for measuring the refraction characteristics of the eye to be inspected, a tonometer, a specular microscope for obtaining corneal characteristics (corneal thickness, cell distribution, etc.), Hartmann -There is a wave front analyzer that obtains the error information of the eye to be inspected using a shack sensor.

In ophthalmic examinations, the alignment between the device optical system and the eye to be inspected is extremely important from the viewpoint of the accuracy and accuracy of the examination. This alignment is called alignment. The alignment includes an operation of aligning the optical axis of the device optical system with the axis of the eye to be inspected (XY alignment) and an operation of aligning the distance between the eye to be inspected and the device optical system (Z alignment).

There are various methods for alignment. As a typical method, a method of projecting light onto the cornea, detecting the reflected image (Purkinje image), and performing alignment is known (see, for example, Patent Document 1).

In addition, as a method realized in recent years, two or more captured images obtained by photographing the anterior segment from different directions are analyzed to identify the three-dimensional position of the eye to be inspected, and XY alignment is performed based on the three-dimensional position. There is a method of performing both and Z alignment (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 10-024019 Japanese Unexamined Patent Publication No. 2013-248376

When the conventional alignment method is used in this way, the following problems may occur.

The Pulkinje image generated when the parallel luminous flux is irradiated is formed at a position deviated in the axial direction (Z direction) from the apex of the cornea by a distance of half the radius of curvature of the cornea. When the Purkinje image is used for Z alignment, the Z position of the Purkinje image is estimated using the standard value of the radius of curvature of the cornea (for example, 8 mm).

However, considering that there are individual differences in the radius of curvature of the cornea and the range ranges from about 6 mm to 9 mm, it is difficult to say that it is preferable to perform Z alignment using a standard value. In particular, it is difficult to apply this conventional method to ophthalmic devices that require high-precision alignment, such as tonometers and specular microscopes.

An object of the present invention is to provide a new method of alignment for ophthalmic devices.

The ophthalmic apparatus of the first aspect of the embodiment provides an index including at least one of a data acquisition optical system for acquiring data of the eye to be inspected and a predetermined continuous pattern and a predetermined discrete pattern of the eye to be inspected. A projection unit that projects onto the anterior segment, two or more imaging units that photograph the anterior segment on which the index is projected from different directions, and two or more first imaging units acquired by the two or more imaging units. Based on the corneal shape information acquisition unit that obtains the corneal shape information of the eye to be inspected based on at least one of the images, the two or more second captured images acquired by the two or more imaging units, and the corneal shape information. It includes a position determining unit that determines a moving target position of the data acquisition optical system.

In the ophthalmic apparatus of the second aspect of the embodiment, the projection unit projects an index of a ring pattern or a concentric circle pattern onto the front eye portion as an index of the continuous pattern.

In the ophthalmic apparatus of the third aspect of the embodiment, the projection unit projects the index of the ring pattern and the central bright spot located at the center of the ring pattern onto the anterior ocular region.

In the ophthalmic apparatus of the fourth aspect of the embodiment, the projection unit projects the index of the concentric pattern and the central bright spot located at the center of the concentric pattern onto the anterior ocular region.

In the ophthalmic apparatus of the fifth aspect of the embodiment, the projection unit uses three or more bright spots arranged on a circle and a central bright spot located at the center of the circle as an index of the discrete pattern. , Projected onto the anterior segment of the eye.

In the ophthalmic apparatus of the sixth aspect of the embodiment, the projection unit projects five or more bright spots arranged on a circle onto the front eye portion as an index of the discrete pattern.

In the ophthalmic apparatus of the seventh aspect of the embodiment, the projection unit projects the central bright spot onto the anterior ocular region by projecting a luminous flux through the optical path of the data acquisition optical system.

In the ophthalmic apparatus of the eighth aspect of the embodiment, the projection unit includes a non-parallel light projection unit that projects non-parallel light onto the anterior eye portion, and the corneal shape information acquisition unit is at least the first captured image. The corneal shape information is obtained based on the projected image of the non-parallel light drawn in.

In the ophthalmic apparatus of the ninth aspect of the embodiment, the projection unit includes a parallel light projection unit that projects parallel light onto the anterior eye portion, and the position-determining unit is visualized on the two or more second captured images. The provisional position determination unit that obtains the provisional movement target position of the data acquisition optical system based on the projected image of the parallel light, and the movement target position that corrects the provisional movement target position based on the corneal shape information. Includes a position correction unit that determines.

The ophthalmic apparatus of the tenth aspect of the embodiment includes a drive unit for moving the data acquisition optical system and a control unit, and the control unit moves the data acquisition optical system to the provisional movement target position. Therefore, the first control of the driving unit is executed, and the corneal shape information acquisition unit obtains the cornea based on the two or more first captured images acquired by the two or more imaging units after the first control. The position correction unit determines the movement target position based on the corneal shape information, and the control unit obtains the data from the provisional movement target position to the movement target position. The second control of the drive unit is executed in order to move the drive unit.

In the ophthalmic apparatus of the eleventh aspect of the embodiment, the provisional position-fixing unit analyzes the two or more second captured images, searches for the projected image of the parallel light, and when the projected image is detected, The provisional movement target position is obtained, and when the projected image is not detected, the pupil image is searched by analyzing the two or more third captured images acquired by the two or more imaging units, and the pupil image is obtained. When detected, the control unit includes a pupil position acquisition unit that obtains a three-dimensional position of the pupil of the eye to be inspected, and the control unit is a drive unit for moving the data acquisition optical system to a position corresponding to the three-dimensional position. The third control of the above is executed, and the provisional position determining unit analyzes two or more photographed images acquired by the two or more photographing units after the third control and searches for the projected image of the parallel light again. ..

The ophthalmic apparatus of the twelfth aspect of the embodiment includes an observation image acquisition unit for acquiring an observation image of the anterior segment of the eye and an operation unit, and when the pupil image is not detected, the control unit uses the control unit. The observation image is displayed on the display means, and the drive unit is controlled according to the operation performed by using the operation unit, and the provisional position determination unit is acquired by the two or more photographing units after the operation. The two or more captured images are analyzed and the projected image of the parallel light is searched again.

In the ophthalmic apparatus of the thirteenth aspect of the embodiment, an index including at least one of a predetermined continuous pattern and a predetermined discrete pattern is projected onto the anterior segment of the eye to be inspected, and the index is projected. One or more captured images acquired by two or more imaging units that photograph the anterior segment from different directions and one or more imaging units that photograph the anterior segment from an oblique direction among the two or more imaging units. Includes a corneal shape information acquisition unit that obtains the corneal shape information of the eye to be inspected based on the above.

According to embodiments, it is possible to provide a new method of alignment for ophthalmic devices.

It is the schematic which shows an example of the structure of the ophthalmic apparatus which concerns on embodiment. It is the schematic which shows an example of the structure of the ophthalmic apparatus which concerns on embodiment. It is the schematic which shows an example of the structure of the ophthalmic apparatus which concerns on embodiment. It is the schematic which shows an example of the structure of the ophthalmic apparatus which concerns on embodiment. It is the schematic which shows an example of the structure of the ophthalmic apparatus which concerns on embodiment. It is the schematic which shows an example of the structure of the ophthalmic apparatus which concerns on embodiment. It is a schematic diagram for demonstrating an example of the process performed by the ophthalmic apparatus which concerns on embodiment. It is a schematic diagram for demonstrating an example of the process performed by the ophthalmic apparatus which concerns on embodiment. It is a schematic diagram for demonstrating an example of the process performed by the ophthalmic apparatus which concerns on embodiment. It is a schematic diagram for demonstrating an example of the process performed by the ophthalmic apparatus which concerns on embodiment. It is a flowchart which shows an example of the operation of the ophthalmic apparatus which concerns on embodiment. It is a flowchart which shows an example of the operation of the ophthalmic apparatus which concerns on embodiment.

An example of an embodiment of the ophthalmic apparatus according to the present invention will be described in detail with reference to the drawings. The ophthalmic apparatus according to the embodiment is used for an optical examination of the eye to be inspected. Such an ophthalmic apparatus includes, for example, at least one of an ophthalmologic imaging apparatus and an ophthalmologic measuring apparatus. Examples of ophthalmologic imaging devices include optical interference tomography, fundus cameras, scanning laser ophthalmoscopes, and the like. Examples of ophthalmic measuring devices include an ophthalmoflex test device, a tonometer, a specular microscope, and a wavefront analyzer. Any known technique, including those disclosed in the literature cited herein, can be combined with embodiments.

<Constitution>
A configuration example of the ophthalmic apparatus is shown in FIGS. 1 and 2. The ophthalmic apparatus 1 has a function of acquiring data of the eye E to be inspected. That is, the ophthalmic apparatus 1 includes one or both of a function of photographing the eye E to be inspected and a function of measuring the characteristics of the eye E to be inspected.

The ophthalmic apparatus 1 includes a control unit 11, a data processing unit 12, an optical unit 20, a face support unit 70, a first drive unit 80A, a second drive unit 80B, and a user interface (UI) 90. .. It should be noted that the configuration may be such that only one of the first drive unit 80A and the second drive unit 80B is provided. Typically, the ophthalmic apparatus 1 may include only the first drive unit 80A.

Each of the control unit 11 and the data processing unit 12 includes a processor. The processor is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), a programmable logic device (for example, a SPLD (Simple Programmable Computer)) (Field Programmable Gate Array)) and the like.

The processor realizes the function according to the embodiment by reading and executing a program stored in a storage circuit or a storage device, for example. At least part of the storage circuit or storage device may be included in the processor. Further, at least a part of the storage circuit and the storage device may be provided outside the processor 10. The processing that can be executed by the processor will be described later.

A storage device or the like stores various types of data. The data stored in the storage device or the like includes data (measurement data, imaging data, etc.) acquired by the data acquisition optical system 30, information on the subject and the eye to be inspected, and the like. Various computer programs and data for operating the ophthalmic apparatus 1 may be stored in the storage device or the like. Various data used / referenced in the processing described later are stored in the storage device or the like.

(Control unit 11)
The control unit 11 controls each unit of the ophthalmic apparatus 1. In particular, the control unit 11 controls the data processing unit 12, the optical unit 20, the first drive unit 80A, the second drive unit 80B, and the user interface 90. The control unit 11 includes an alignment control unit 111 and a UI control unit 112.

(Alignment control unit 111)
The alignment control unit 111 executes control related to alignment. The ophthalmic apparatus 1 can perform alignment (index alignment mode) based on the index projected on the anterior segment Ea. Although the details will be described later, in the index alignment mode, correction based on the corneal shape information of the eye E to be inspected is possible.

The corneal shape information includes, for example, any parameter value representing the shape of the cornea that can be measured using a known ophthalmic apparatus. Typically, the corneal shape information includes the radius of curvature (curvature), the orientation of the strong main meridian, the radius of curvature along the strong main meridian (frequency), the orientation of the weak main meridian, the radius of curvature along the weak main meridian (frequency), It may include any of ellipticity, eccentricity, flatness, topograph including irregular anomaly, aberration information using Zernike polynomials, and the like.

Further, the alignment control unit 111 may be able to perform alignment based on the characteristic portion of the eye E to be inspected (pupil alignment mode) and alignment manually performed by the examiner (manual alignment). The alignment control unit 111 executes the process of selecting the alignment mode and the control of each unit in the selected alignment mode. A specific example of the process executed by the alignment control unit 111 will be described later.

(UI control unit 112)
The UI control unit 112 controls the user interface 90. In other words, the UI control unit 112 controls the exchange of information between the ophthalmic apparatus 1 and the user. Typically, the UI control unit 112 executes control for displaying information on the display unit 91 and control according to an operation performed by using the operation unit 92. The output mode of the information by the ophthalmic apparatus 1 is not limited to the display output, and may include audio output, print output, lighting of a light emitting diode, and the like. Specific examples of the processing executed by the UI control unit 112 will be described later.

(Data processing unit 12)
The data processing unit 12 executes various data processing. For example, the data processing unit 12 analyzes the image acquired by the anterior segment camera 60. The image analysis result is used for alignment and the like. The details of the data processing unit 12 will be described later (see FIG. 2).

(Optical unit 20)
The optical unit 20 stores a configuration for measuring and / or photographing the eye E to be inspected, and a configuration for preparing the configuration. The former includes a data acquisition optical system 30, and the latter includes an alignment optical system and an anterior segment camera 60. The alignment optical system is used in alignment and includes a first light projection unit 41 and a second light projection unit 42 in this embodiment.

In a typical example, the data acquisition optical system 30 and the first light projection unit 41 are housed inside the optical unit 20. The second light projection unit 42 is installed on the surface of the housing of the optical unit 20, or a part of the second light projection unit 42 is exposed on the surface of the housing. Similarly, the anterior segment camera 60 is installed on the surface of the housing of the optical unit 20, or a part thereof is exposed on the surface of the housing.

The first light projection unit 41 includes an optical system arranged inside the optical unit 20. The optical path formed by the optical system of the first light projection unit 41 is combined with the optical path of the data acquisition optical system 30 by the beam splitter 50. Although not shown, various optical members such as an objective lens are provided between the beam splitter 50 and the eye E to be inspected.

In addition to the configuration shown in FIG. 1, the optical unit 20 may be provided with an optical system (illumination optical system, observation optical system, photographing optical system, etc.) for photographing the eye E to be inspected from the front. Further, a configuration for focusing the data acquisition optical system 30 may be provided. In a typical embodiment, the optical system for photographing the eye E to be examined from the front is not provided, and both the alignment and the anterior segment imaging for acquiring the corneal shape information are performed by the anterior segment camera. It is configured to be performed using 60. However, the embodiment is not limited to such a configuration.

(Data acquisition optical system 30)
The data acquisition optical system 30 includes a configuration for measuring the characteristics of the eye E to be inspected and / or a configuration for photographing the eye E to be inspected. The data acquisition optical system 30 is configured according to the functions (measurement function, imaging function, etc.) provided by the ophthalmic apparatus 1. The data acquisition optical system 30 is provided with, for example, a light source, an optical element (optical member, an optical device), an actuator, a mechanism, a circuit, a display device, a light receiving element, an image sensor, and the like.

The configuration of the data acquisition optical system 30 may be similar to that of a conventional ophthalmic apparatus. At least a part of the data acquisition optical system 30 may be arranged outside the optical path synthesized in the optical path of the first light projection unit 41.

The data acquisition optical system 30 may include a configuration for providing a function associated with the inspection. For example, an fixation optical system for projecting an optotype (fixation target) for fixing the eye E to be inspected on the fundus of the eye E may be provided.

(Detection of the position of the data acquisition optical system 30)
The ophthalmic apparatus 1 has a function of detecting the position of the data acquisition optical system 30. For example, the control unit 11 can record the content of control for the first drive unit 80A and / or the second drive unit 80B, and can obtain the position of the data acquisition optical system 30 from this record (control history). In another example, the ophthalmic apparatus 1 includes a position sensor that detects the position of the data acquisition optical system 30.

The control unit 11 (alignment control unit 111, etc.) has the first drive unit 80A and / or the second drive unit 80B based on the position of the data acquisition optical system 30 and the movement target position determined by the data processing unit 12. Can be controlled. Thereby, the data acquisition optical system 30 can be moved to the moving target position. Specifically, the control unit 11 obtains the difference between the position of the data acquisition optical system 30 and the moving target position. This difference is, for example, a vector value starting from the detected position of the data acquisition optical system 30 and ending at the moving target position. This vector value is, for example, a three-dimensional vector value represented by the XYZ coordinate system.

(1st light projection unit 41)
The first light projection unit 41 includes, for example, a light source and a collimating lens, and projects light onto the anterior segment Ea. In this embodiment, the first light projection unit 41 projects substantially parallel light (parallel light) onto the anterior segment Ea. Thereby, an index for alignment is projected on the anterior segment Ea. This index is detected as a Purkinje image. Alignment using the index includes, for example, one or both of Z alignment and XY alignment. The Z alignment is an alignment in the optical axis direction (Z direction) of the data acquisition optical system 30. XY alignment is an alignment in the X direction (horizontal direction) and the Y direction (vertical direction) orthogonal to the Z direction.

Z alignment is performed, for example, by analyzing two or more captured images obtained substantially simultaneously by two or more anterior segment cameras 60. XY alignment is performed, for example, by analyzing two or more captured images obtained substantially simultaneously by two or more anterior segment cameras 60.

The XY alignment of the anterior segment Ea is performed based on the position of the Purkinye image (index image) drawn in the image of the anterior segment Ea acquired by any one or more of the two or more anterior segment cameras 60 in the XY direction. Will be done. For example, the XY alignment based on the image of the anterior segment Ea is performed by manually or automatically moving the optical unit 20 so as to guide the index image within the allowable range (alignment mark) of the misalignment.

Further, the image of the anterior segment Ea acquired by any of the two or more anterior segment cameras 60 (in other words, acquired by the anterior segment camera 60 arranged at a position out of the optical path of the data acquisition optical system 30). It is possible to apply an image process for converting an image, that is, an image obtained by photographing the anterior segment Ea from an oblique direction, into an image viewed from the front. This process is, for example, a viewpoint conversion based on the viewing angle of the anterior segment camera 60 (the position of the anterior segment camera 60). It is possible to perform XY alignment using the front image formed through such image processing.

In the case of manual alignment, the UI control unit 112 displays the image of the anterior segment Ea and the alignment mark on the display unit 91, and the user operates the operation unit 92 so as to satisfy the above conditions. Further, in manual alignment, the UI control unit 112 can display information for assisting the user's operation on the display unit 91. For example, it is possible to display information indicating the misalignment direction and / or the amount of misalignment, or to display the direction and / or amount to move the optical unit 20.

In the case of auto alignment, the data processing unit 12 calculates the displacement of the index image with respect to the alignment mark, and the alignment control unit 111 moves the optical unit 20 in the XY direction so as to cancel this displacement.

(Second light projection unit 42)
The second light projection unit 42 is arranged on the front surface of the optical unit 20 (the surface facing the eye E to be inspected). The second light projection unit 42 projects, for example, one or both of a predetermined continuous pattern index and a predetermined discrete pattern index onto the anterior segment Ea.

The continuous pattern is, for example, a ring pattern or a concentric pattern. When the index of the ring pattern is applied, the central bright spot located at the center of the ring pattern can be further projected onto the anterior segment Ea. Similarly, when the index of the concentric pattern is applied, the central bright spot located at the center of the concentric pattern can be further projected onto the anterior segment Ea. The central bright spot is formed by, for example, the first light projection unit 41.

Indicators of continuous patterns are not limited to these. For example, an ellipse pattern, an arbitrary curve pattern, an arbitrary straight line pattern, or the like can be applied. Also, the continuous pattern does not have to be a closed curve. For example, the continuous pattern may be part of a circle, part of a concentric circle, part of an ellipse, and so on. Further, the continuous pattern may be a planar pattern having a two-dimensional spread.

The index of the discrete pattern may include any number of bright spots (dotted indexes). Further, the index of the discrete pattern may include an arbitrary number of bright lines (line segment-like index), an arbitrary number of planar patterns, and the like. For example, an index of a discrete pattern may include three or more bright spots arranged on a circle and a central bright spot located at the center of the circle. This central bright spot is formed by, for example, the first light projection unit 41. As another example, the discrete pattern index may include 5 or more bright spots arranged on a circle.

The second light projection unit 42 includes an arbitrary light source. The light source may be a light emitting device or a combination of a light emitting device and an optical element. A typical example of a light emitting device is a light emitting diode (LED). The light emitting device may have a shape corresponding to the pattern of the index. Further, the second light projection unit 42 may include a plurality of light emitting devices arranged according to the pattern of the index. A diffuser is a typical example of an optical element combined with a light emitting device. Further, an optical element having an opening or a translucent portion having a shape corresponding to the pattern of the index can be combined with the light emitting device.

In this embodiment, the second light projection unit 42 projects light (non-parallel light) onto the anterior segment Ea from a finite distance. The projected image is used to acquire the corneal shape information of the eye E to be inspected. Both the projected image (index) formed by the first light projection unit 41 and the projected image (index) formed by the second light projection unit 42 are used to acquire the corneal shape information of the eye E to be inspected. can do. For example, when the number of projection images of the discrete pattern formed by the second light projection unit 42 is relatively small, or when the projection image of the continuous pattern is formed by the second light projection unit 42. It can be configured to utilize the projected image formed by the first light projection unit 41.

The second light projection unit 42 can be used as anterior segment illumination. The anterior segment illumination is used when observing the anterior segment Ea.

Specific examples of the first light projection unit 41 and the second light projection unit 42 will be described later.

(Anterior segment camera 60)
Two or more front eye cameras 60 are provided at different positions. Each anterior segment camera 60 is, for example, a video camera that shoots a moving image at a predetermined frame rate. The two or more anterior segment cameras 60 capture the anterior segment from different directions substantially simultaneously.

In the example shown in FIG. 1, the data acquisition optical system 30 or the like is provided at a position outside the optical path, but the present invention is not limited to this. For example, when the data acquisition optical system 30 is provided with an image sensor, one of two or more anterior segment cameras may be this image sensor.

In this embodiment, for example, as shown in FIG. 3, two anterior segment cameras 60A and 60B are provided. Note that FIG. 3 is a top view, in which the + Y direction indicates a vertically upward direction, and the + Z direction indicates the optical axis direction of the data acquisition optical system 30 and the direction from the data acquisition optical system 30 toward the eye E to be inspected. Further, the anterior segment cameras 60A and 60B are provided at positions outside the optical path of the data acquisition optical system 30, respectively. Hereinafter, the two anterior segment cameras 60A and 60B may be collectively represented by the reference numeral “60”.

The number of anterior segment cameras may be any number of 2 or more, but any configuration can be used as long as the anterior segment can be photographed substantially simultaneously from two different directions. Further, one anterior segment camera may be arranged coaxially with the data acquisition optical system 30.

“Substantially at the same time” means that, for example, in imaging with two or more anterior segment cameras, a shift in imaging timing to the extent that eye movements can be ignored is allowed. Thereby, an image when the eye E to be inspected is in substantially the same position (orientation) can be acquired by two or more anterior eye cameras.

Further, the shooting by two or more front eye cameras may be a moving image shooting or a still image shooting, but in this embodiment, a case where the moving image shooting is performed will be described in particular detail. In the case of moving image shooting, by controlling the shooting start timing to be adjusted, and controlling the frame rate and the shooting timing of each frame, it is possible to realize the above-mentioned substantially simultaneous front eye shooting. On the other hand, in the case of still image shooting, this can be realized by controlling the shooting timing to be adjusted.

Examples of the configuration of the front surface of the housing of the optical unit 20 are shown in FIGS. 4A to 4C. Reference numeral "51" indicates an objective lens. The objective lens 51 is arranged in front of the beam splitter 50 (on the E side of the eye to be inspected). The objective lens 51 is arranged at the foremost position (the position closest to the eye E to be inspected) of the member group forming the optical path of the data acquisition optical system 30, and is an optical path connecting the first light projection unit 41 and the eye E to be inspected. It is arranged at the foremost position of the member group forming the above.

It is also possible to apply a configuration in which an optical element or the like can be arranged in front of the objective lens 50. For example, when the ophthalmic apparatus 1 includes an optical interference tomography for fundus photography, the attachment lens for anterior ocular segment imaging can be configured to be arranged in front of the objective lens 51.

The member arranged at the frontmost position of the data acquisition optical system 30 is not limited to the objective lens 51. For example, when the ophthalmic apparatus 1 includes a tonometer, a nozzle for blowing an air flow on the surface of the cornea is arranged at the foremost position.

The example shown in FIG. 4A will be described. In this example, the objective lens 51 is arranged slightly above the center position of the housing of the optical unit 20. At the time of examination, the objective lens 51 is arranged so as to face the anterior segment Ea.

In this example, the anterior segment camera 60A is arranged on the left side of the objective lens 50, and the anterior segment camera 60B is arranged on the right side. In this example, the height position of the objective lens 50 (position in the Y direction) and the height positions of the anterior segment cameras 60A and 60B are designed to be equal, but the present invention is not limited to this. For example, the anterior segment cameras 60A and 60B can be arranged below the center of the objective lens 50 (in the −Y direction). As a result, it is possible to reduce the possibility that the eyelids and eyelashes of the subject are reflected in the captured images acquired by the anterior segment cameras 60A and 60B. Further, even a subject having a deep dent (orbit) of the eye can preferably perform anterior segment imaging. As another example, the height position of the anterior segment camera 60A and the height position of the anterior segment camera 60B can be designed to be different.

The second light projection unit 42A of this example includes one or more light sources having a continuous shape (a light emitting device or a combination of a light emitting device and an optical element). The second light projection unit 42A is, for example, a ring-shaped light source (keratling light source) or a concentric light source (platidd ring light source) used in an ophthalmic apparatus (keratometer, corneal topographer, etc.) for measuring the shape of the cornea. The keratling light source outputs a luminous flux having a ring-shaped cross section for projecting an index of the ring pattern onto the anterior segment Ea. The platidling light source outputs a luminous flux having a concentric cross section for projecting an index of the concentric pattern on the anterior segment Ea.

In the example shown in FIG. 4A, the second light projection unit 42A is a platid ring light source in which three ring-shaped light sources are concentrically arranged. The number of ring-shaped light sources constituting the platiding light source may be arbitrary.

The example shown in FIG. 4B will be described. In this example, the configuration and arrangement of the objective lens 51, the anterior segment camera 60A, and the anterior segment camera 60B are the same as the example shown in FIG. 4A. In addition, other configurations and / or arrangements may be applied.

The second light projection unit 42B of this example includes three point light sources (a light emitting device or a combination of a light emitting device and an optical element). The three point light sources 42B are arranged at the vertices of an equilateral triangle whose center of gravity is the position of the optical axis of the objective lens 51. The arrangement of the three point light sources is not limited to this, and may be arbitrary.

An example shown in FIG. 4C will be described. In this example, the configuration and arrangement of the objective lens 51, the anterior segment camera 60A, and the anterior segment camera 60B are the same as the example shown in FIG. 4A. In addition, other configurations and / or arrangements may be applied.

The second light projection unit 42C of this example includes five point light sources (a light emitting device or a combination of a light emitting device and an optical element). The five point light sources 42B are arranged at the vertices of a regular pentagon whose center of gravity is the position of the optical axis of the objective lens 51. The arrangement of the five point light sources is not limited to this, and may be arbitrary.

In the examples shown in FIGS. 4A to 4C, the relative positions between the objective lens 51, the anterior segment cameras 60A and 60B, and the second light projection unit 42 are fixed. In another example, at least one of these members can be configured to be movable. For example, a mechanism for moving the anterior segment camera 60A and / or 60B may be provided. Further, a mechanism for moving the light source included in the second light projection unit 42 may be provided. In that case, a function of detecting the position of the movable member is provided.

Further, when the second light projection unit 42 includes a light source having a continuous shape, a mechanism for changing the shape of the light source can be provided.

(Face support 70)
The face support portion 70 includes a member for supporting the face of the subject. For example, the face support portion 70 includes a forehead pad on which the forehead of the subject is abutted and a chin rest on which the chin of the subject is placed. The face support portion 70 may include only one of the forehead pad and the chin rest, and may include members other than these.

(1st drive unit 80A and 2nd drive unit 80B)
The first drive unit 80A moves the optical unit 20 under the control of the control unit 11 (alignment control unit 111 or the like). The first drive unit 80A can move the optical unit 20 three-dimensionally. The first drive unit 80A includes, for example, a mechanism for moving the optical unit 20 in the X direction, a mechanism for moving the optical unit 20 in the Y direction, and a mechanism for moving the optical unit 20 in the Z direction, as in the conventional case. Further, the first drive unit 80A may include a rotation mechanism for rotating the optical unit 20 in a plane (horizontal plane, vertical plane, etc.) including the optical axis of the optical unit 20.

The second drive unit 80B moves the face support unit 70 under the control of the control unit 11 (alignment control unit 111 or the like). The second drive unit 80B can move the face support unit 70 three-dimensionally. The second drive unit 80B includes, for example, a mechanism for moving the face support unit 70 in the X direction, a mechanism for moving the face support unit 70 in the Y direction, and a mechanism for moving the face support unit 70 in the Z direction. Further, the second drive unit 80B may include a rotation mechanism for changing the direction of the face support unit 70 (or a member included therein). When the face support portion 70 is provided with a plurality of members, the second drive unit 80B may be configured to move these members individually. For example, the second drive unit 80B may be configured to move the forehead rest and the chin rest individually.

(User interface 90)
The user interface 90 provides functions for exchanging information between the ophthalmic apparatus 1 and its user, such as displaying information, inputting information, and inputting operation instructions. The user interface 90 provides an output function and an input function. The user interface 90 is controlled by the UI control unit 112.

A display unit 91 is a typical example of a configuration that provides an output function. The display unit 91 includes a display device such as a flat panel display. Other examples of configurations related to output functions include audio output devices and light emitting diodes.

An operation unit 92 is a typical example of a configuration that provides an input function. The operation unit 92 includes operation devices such as levers, buttons, keys, and pointing devices. Further, as another example of the configuration related to the input function, there is a microphone and a data writer.

The user interface 90 may include a device such as a touch panel display in which an output function and an input function are integrated. The user interface 90 may also include a graphical user interface (GUI) for inputting and outputting information.

(Details of data processing unit 12)
The details of the data processing unit 12 will be described. As shown in FIG. 2, the data processing unit 12 is provided with an image correction unit 120, a corneal shape information acquisition unit 130, a position determination unit 140, and a pupil position acquisition unit 150. These work for alignment.

(Image correction unit 120)
The image correction unit 120 corrects the distortion of the captured image obtained by the front eye camera 60 based on predetermined aberration information. This process is performed, for example, by a known image processing technique based on a correction factor for correcting distortion. It is not necessary to provide the image correction unit 120 when the distortion aberration given to the captured image by the optical system of the front eye camera 60 is sufficiently small.

Aberration information is stored in advance in, for example, a storage device provided in the ophthalmic apparatus 1. Alternatively, it can be configured so that the ophthalmologic device 1 can refer to the aberration information stored in advance in the external device. In the aberration information, information on the distortion aberration generated in the captured image due to the influence of the optical system mounted on each anterior segment camera 60 is recorded. Here, the optical system mounted on the anterior segment camera 60 includes an optical element such as a lens that generates distortion. Aberration information can be said to be a parameter that quantifies the distortion given to the captured image by these optical elements.

An example of a method of generating aberration information will be described. The following measurements are performed for each anterior segment camera 60 in consideration of the instrumental error (difference in distortion) of the anterior segment camera 60. The worker prepares a predetermined reference point. The reference point is a photographing target used for detecting distortion. The operator takes a plurality of times while changing the relative position between the reference point and the anterior segment camera 60. As a result, a plurality of captured images of reference points taken from different directions can be obtained. The operator generates aberration information for the anterior segment camera 60 by analyzing the acquired plurality of captured images with a computer.

The analysis process for generating aberration information includes, for example, the following steps.
-Extraction step to extract the image area corresponding to the reference point from each captured image-Distribution state calculation process to calculate the distribution state (coordinates) of the image area corresponding to the reference point in each captured image-Based on the obtained distribution state Distortion aberration calculation process for calculating the parameters representing the distortion aberration ・ Correction coefficient calculation process for calculating the coefficient for correcting the distortion aberration based on the obtained parameters

The parameters related to the distortion given to the image by the optical system include the principal point distance, the principal point position (vertical direction, horizontal direction), and lens distortion (radiation direction, tangential direction). The aberration information is configured as information (for example, table information) in which the identification information of each anterior segment camera 60 and the corresponding correction coefficient are associated with each other. The image correction unit 120 corrects the aberration of the captured image acquired by the anterior segment camera 60A or 60B by referring to the aberration information generated in this way. Such aberration correction is called calibration or the like.

The captured image corrected by the image correction unit 120 is sent to at least one of the corneal shape information acquisition unit 130, the position determination unit 140, and the pupil position acquisition unit 150. In a typical example, the control unit 11 (alignment control unit 111, etc.) is configured to switch the transmission destination of the captured image corrected by the image correction unit 120 according to the operation mode and the processing phase.

(Corneal shape information acquisition unit 130)
The corneal shape information acquisition unit 130 obtains the corneal shape information of the eye E to be inspected based on the two captured images (first captured images) acquired by the anterior segment cameras 60A and 60B. The corneal shape information includes any of the parameter values described above.

The corneal shape information acquisition unit 130 is configured to obtain corneal shape information based on at least an index formed by the second light projection unit 42. Further, the corneal shape information acquisition unit 130 is configured to obtain corneal shape information based on an index formed by the first light projection unit 41 and an index formed by the second light projection unit 42.

When the second light projection unit 42A shown in FIG. 4A is applied, the corneal shape information acquisition unit 130 obtains the corneal shape information based on, for example, the index of the concentric pattern formed by the second light projection unit 42A. It is composed. In another example, the corneal shape information acquisition unit 130 provides corneal shape information based on an index (bright spot) formed by the first light projection unit 41 and an index of a concentric pattern formed by the second light projection unit 42A. Is configured to ask for.

When the second light projection unit 42B shown in FIG. 4B is applied, the corneal shape information acquisition unit 130 is formed by, for example, an index (bright spot) formed by the first light projection unit 41 and the second light projection unit 42B. It is configured to obtain corneal shape information based on four indexes including three indexes (bright spots).

When the second light projection unit 42C shown in FIG. 4C is applied, the corneal shape information acquisition unit 130 obtains corneal shape information based on, for example, five indexes (bright spots) formed by the second light projection unit 42C. It is configured to ask. In another example, the corneal shape information acquisition unit 130 includes an index (bright spot) formed by the first light projection unit 41 and five indexes (bright spot) formed by the second light projection unit 42C6. It is configured to obtain corneal shape information based on one index.

An example of the process executed by the corneal shape information acquisition unit 130 will be described. Hereinafter, the case where the light projection units 42A to 42C shown in FIGS. 4A to 4C are applied will be exemplified, but the same processing is applied to the case where the second light projection unit 42 of another form is applied. can do.

A case where the second light projection unit 42A shown in FIG. 4A is applied will be described. FIG. 5A shows an example of two captured images (anterior segment images) acquired substantially simultaneously by the anterior segment cameras 60A and 60B. The captured image 200A is an anterior segment image acquired by the anterior segment camera 60A, and the captured image 200B is an anterior segment image acquired by the anterior segment camera 60B. Here, the captured images 200A and 200B may be anterior segment images corrected by the image correction unit 120.

The captured image 200A is an image obtained by photographing the anterior segment Ea from an oblique direction. The captured image 200A includes a pupil image 201A corresponding to the pupil Ep of the eye E to be inspected, a bright spot image (Purkinje image) 202A formed by the first light projection unit 41, and a second light projection unit 42A. The index 203A of the concentric pattern is drawn.

Similarly, the captured image 200B is an image obtained by photographing the anterior segment Ea from an oblique direction different from that of the captured image 200A. The captured image 200B includes a pupil image 201B corresponding to the pupil Ep of the eye E to be inspected, a bright spot image (Purkinje image) 202B formed by the first light projection unit 41, and a second light projection unit 42A. The index 203B of the concentric pattern is drawn.

In this example, the captured images 200A and 200B were acquired by photographing from a direction different from the optical axis of the objective lens 51 (that is, the optical axis of the data acquisition optical system 30 and the optical axis of the first optical projection unit 41). It is an image. Further, when the XY alignment is substantially aligned, the Purkinje images 202A and 202B are formed on the optical axis of the objective lens 51.

The viewing angle of the front eye camera 60A (the angle of the objective lens 51 with respect to the optical axis) and the viewing angle of the front eye camera 60B are known, respectively. Furthermore, the shooting magnification is also known. Therefore, based on the depiction position of an arbitrary object in the captured image 200A and the depiction position of the object in the captured image 200B, the relative position (in real space) of the object with respect to the ophthalmic apparatus 1 (anterior eye camera 60A and 60B). (Three-dimensional position) can be obtained (see the description of the position determination unit 140 described later).

Further, since the anterior segment cameras 60A and 60B are arranged at positions deviating from the optical axis of the objective lens 51, the indexes 203A and 203B of the concentric pattern drawn in the captured images 200A and 200B, respectively, are detected as ellipses. Will be done. In the present specification, the index of the concentric circle pattern shall also include the index of the concentric ellipse pattern (typical actual projection image). Similarly, the index of the ring pattern shall also include the index of the elliptical pattern (typical actual projection image).

In this example, the corneal shape information acquisition unit 130 first searches for the index 203A of the concentric pattern by analyzing the captured image 200A. This processing includes, for example, a threshold processing regarding the pixel value of the captured image 200A for searching for a pixel corresponding to the index 203A (a pixel having a higher brightness than the surroundings). Thereby, the index 203A is specified. Depending on the alignment state and the like, the indexes of all the ring patterns corresponding to the plurality of ring-shaped light sources included in the second light projection unit 42A may not be specified.

When the index 203A of the concentric pattern is identified, the corneal shape information acquisition unit 130 analyzes at least one of the indexes of the ring pattern included in the index 203A, similarly to the conventional keratometer and the corneal topographer, to analyze the ring pattern. Find the diameter (radius, diameter) of the index of. At this time, the diameter can be obtained in a plurality of directions.

Further, the corneal shape information acquisition unit 130 obtains an approximate ellipse of the index of the ring pattern, and based on this approximate ellipse, the direction of the strong main meridian, the radius of curvature in the direction of the strong main meridian, the direction of the weak main meridian, and the weak main meridian. The radius of curvature in the direction can be obtained. The approximate ellipse is obtained, for example, by fitting a plurality of points on the index of the ring pattern to a standard ellipse equation using the method of least squares.

Another example will be described. Since the prospect angles of the anterior segment cameras 60A and 60B are known, the distance between the eye to be inspected and the anterior segment cameras 60A and 60B is known, and the radius of curvature of the cornea of the eye to be inspected is a predetermined reference value ( Assuming that it is equal to (for example, a standard value), the amount of ellipse (direction of strong main meridian, direction of weak main meridian, ellipticity, eccentricity, flatness) of indexes 203A and 203B projected on such a standard eye to be inspected. Parameter values that represent the shape of the ellipse, such as the rate) can be obtained in advance.

The corneal shape information acquisition unit 130 can utilize the standard elliptical amount acquired in advance in this way. For example, the corneal shape information acquisition unit 130 calculates the elliptical amount from the index 203A of the concentric pattern obtained by actually photographing the anterior eye portion Ea of the eye E to be inspected, and the difference between the elliptical amount and the standard elliptical amount. It is possible to obtain the corneal shape information of the eye E to be inspected based on this difference.

When performing an operation on an ellipse, the center of the ellipse can be obtained from the index 203A of the concentric pattern, but it is also possible to use the bright spot image (Pulkinje image) 202A formed by the first light projection unit 41 as the center of the ellipse. ..

The above processing is an example of obtaining corneal shape information based only on the captured image 200A. By the same processing, the corneal shape information can be obtained from the captured image 200B. It is also possible to obtain the corneal shape information based on the (provisional) corneal shape information based on the captured image 200A and the (provisional) corneal shape information based on the captured image 200B. For example, statistical values (average value, etc.) of two provisional corneal shape information may be calculated.

In this example to which the second light projecting unit 42A shown in FIG. 4A is applied, the following known elliptical equation can be used: [{(xx ₀ ) sinθ + (y−y ₀ ) cosθ}. ² / a ² ] + [{(x−x ₀ ) cosθ + (y−y ₀ ) sinθ} ² / b ² ] = 1. In this equation, both the axis angle and the center position represent an ellipse indefinite, (x ₀ , y ₀ ) indicates the center coordinates, θ indicates the axis angle, a indicates the major axis, and b indicates the minor axis. When this equation is used, the ellipse can be determined from the coordinates of at least 5 points on the circumference of the ellipse.

A case where the second light projection unit 42B shown in FIG. 4B is applied will be described. FIG. 5B shows an example of two captured images (anterior segment images) acquired substantially simultaneously by the anterior segment cameras 60A and 60B. The captured image 300A is an anterior segment image acquired by the anterior segment camera 60A, and the captured image 300B is an anterior segment image acquired by the anterior segment camera 60B. Here, the captured images 300A and 300B may be anterior segment images corrected by the image correction unit 120.

The captured image 300A is an image obtained by photographing the anterior segment Ea from an oblique direction. The captured image 300A includes a pupil image 301A corresponding to the pupil Ep of the eye E to be inspected, a bright spot image 302A formed by the first light projection unit 41, and three bright spots formed by the second light projection unit 42B. Image 303A is depicted.

Similarly, the captured image 300B is an image obtained by photographing the anterior segment Ea from an oblique direction different from that of the captured image 300A. The captured image 300B includes a pupil image 301B corresponding to the pupil Ep of the eye E to be inspected, a bright spot image 302B formed by the first light projection unit 41, and three bright spots formed by the second light projection unit 42B. Image 303B is depicted.

In this example, the captured images 300A and 300B were acquired by photographing from a direction different from the optical axis of the objective lens 51 (that is, the optical axis of the data acquisition optical system 30 and the optical axis of the first optical projection unit 41). It is an image. Further, when the XY alignment is substantially aligned, the bright spot images 302A and 302B are formed on the optical axis of the objective lens 51.

The viewing angle of the front eye camera 60A, the viewing angle of the front eye camera 60B, and the photographing magnification are known. Therefore, based on the depiction position of an arbitrary object in the captured image 300A and the depiction position of the object in the captured image 300B, the relative position (in real space) of the object with respect to the ophthalmic apparatus 1 (anterior eye camera 60A and 60B). (Three-dimensional position) can be obtained (see the description of the position determination unit 140 described later).

In this example, the corneal shape information acquisition unit 130 first searches for the bright spot image 302A and the three bright spot images 303A by analyzing the captured image 300A. This processing includes, for example, a threshold processing regarding the pixel value of the captured image 300A for searching for a pixel corresponding to a bright spot image (a pixel having a higher brightness than the surroundings). Thereby, the bright spot image 302A and the three bright spot images 303A are specified.

The corneal shape information acquisition unit 130 executes labeling processing of the four identified bright spot images 302A and 303A. The labeling process is a process for identifying which of the light sources included in the first light projection unit 41 and the second light projection unit 42B each of the four bright spot images 302A and 303A corresponds to. An example of the labeling processing method will be described below. The labeling processing method is not limited to these examples.

In the first example of the labeling process, the corneal shape information acquisition unit 130 can add identification information to the bright spot image based on the relative position of the bright spot image with respect to a predetermined position of the image frame of the captured image 300A. .. Examples of a predetermined position that serves as a reference for this processing include the center, upper end, lower end, left end, and right end of the image frame.

In the second example of the labeling process, the corneal shape information acquisition unit 130 imparts identification information to the bright spot image based on the relative position of the bright spot image with respect to a predetermined portion of the eye E to be inspected drawn on the photographed image 300A. can do. Examples of a predetermined site that serves as a reference for this treatment include the center of the pupil (center of gravity of the pupil), the center of the iris (center of gravity of the iris), and the diseased part.

The third example of the labeling process is applicable when a plurality of bright spot images are drawn on the captured image 300A. The corneal shape information acquisition unit 130 can add identification information to each of the bright spot images based on the positional relationship between the plurality of bright spot images drawn on the captured image 300A.

In the fourth example of the labeling process, the configuration and / or control of the first light projection unit 41 and / or the second light projection unit 42B is used to discriminate different bright spot images. For example, a plurality of different light sources are configured to output light having different characteristics (light intensity, wavelength, etc.). Alternatively, a plurality of different light sources are configured or controlled to be intensity-modulated (blinking, etc.) at different frequencies.

When the labeling process is completed, the corneal shape information acquisition unit 130 obtains the corneal shape information of the eye E to be inspected based on the positions of the four bright spot images 302A and 303A.

In this example to which the second light projecting unit 42B shown in FIG. 4B is applied, the following known elliptical equation can be used: {(xsinθ + ycosθ) ² / a ² } + {(xcosθ + ysinθ) ² / b. ² } = 1. This equation represents an ellipse whose center position is known, where (x ₀ , y ₀ ) = (0, 0) is the center coordinate, θ is the axial angle, a is the major axis, and b is the minor axis. When the center of the ellipse is specified from the bright spot image 302A in this way, the ellipse can be determined by obtaining the three unknowns a, b, and θ from the coordinates of at least three points on the circumference of the ellipse.

The above processing is an example of obtaining corneal shape information based only on the captured image 300A. By the same processing, the corneal shape information can be obtained from the captured image 300B.

On the other hand, it is also possible to obtain corneal shape information based on both the captured images 300A and 300B. In that case, for example, the corneal shape information acquisition unit 130 determines, for each of the bright spot images 302A and 303A, the drawing position of the bright spot image in the captured image 300A, the drawing position of the bright spot image in the captured image 300B, and the anterior eye. The relative position (three-dimensional position in the real space) of the bright spot image with respect to the ophthalmic apparatus 1 can be obtained based on the viewing angle of the part camera 60A, the viewing angle of the anterior eye part camera 60B, and the imaging magnification.

If any of the four bright spot images 302A and 303A is not detected from the captured image 300A, the alignment control unit 111 adjusts the alignment, and then the corneal shape information acquisition unit 130 searches for the bright spot image again. It can be carried out.

Further, in this embodiment, parallel light is projected coaxially with the data acquisition optical system 30, and non-parallel light is projected non-collimated with the data acquisition optical system 30, but the present invention is not limited to this. For example, it can be configured to project non-parallel light coaxially with the data acquisition optical system 30 and project parallel light non-collimated with the data acquisition optical system 30. Alternatively, both parallel light and non-parallel light can be configured to be projected non-coaxially with the data acquisition optical system 30.

In other embodiments, all the luminous fluxes for measuring the corneal shape may be parallel luminous fluxes. In this case, since the influence of the alignment (particularly Z alignment) state on the corneal shape measurement is small, it is not necessary to correct the corneal shape according to the alignment state.

A case where the second light projection unit 42C shown in FIG. 4C is applied will be described. FIG. 5C shows an example of two captured images (anterior segment images) acquired substantially simultaneously by the anterior segment cameras 60A and 60B. The captured image 400A is an anterior segment image acquired by the anterior segment camera 60A, and the captured image 400B is an anterior segment image acquired by the anterior segment camera 60B. Here, the captured images 400A and 400B may be anterior segment images corrected by the image correction unit 120.

The captured image 400A is an image obtained by photographing the anterior segment Ea from an oblique direction. In the captured image 400A, a pupil image 401A corresponding to the pupil Ep of the eye E to be inspected and five bright spot images 403A formed by the second light projection unit 42C are depicted. In this example, the bright spot image formed by the first light projection unit 41 is not drawn. However, in another example, the bright spot image formed by the first light projection unit 41 can be used.

Similarly, the captured image 400B is an image obtained by photographing the anterior segment Ea from an oblique direction different from that of the captured image 400A. In the captured image 400B, a pupil image 401B corresponding to the pupil Ep of the eye E to be inspected and five bright spot images 403B formed by the second light projection unit 42 are depicted.

In this example, the captured images 400A and 400B are images acquired by photographing from a direction different from the optical axis of the objective lens 51 (that is, the optical axis of the data acquisition optical system 30).

Since the viewing angle of the front eye camera 60A, the viewing angle of the front eye camera 60B, and the photographing magnification are known, the drawing position of an arbitrary object in the captured image 400A and the drawing position of the target in the captured image 400B can be set. Based on this, the relative position (three-dimensional position in the real space) of the object with respect to the ophthalmic apparatus 1 (anterior eye camera 60A and 60B) can be obtained (see the description of the positioning unit 140 described later).

In this example, the corneal shape information acquisition unit 130 first searches for five bright spot images 403A by analyzing the captured image 400A. This processing includes, for example, a threshold processing regarding the pixel value of the captured image 400A for searching for a pixel corresponding to the bright spot image 403A (a pixel having a higher brightness than the surroundings). Thereby, five bright spot images 403A are identified.

The corneal shape information acquisition unit 130 executes the labeling process of the specified bright spot image 403A. The labeling process is a process for identifying which of the light sources included in the second light projection unit 42C each of the five bright spot images 403A corresponds to. The labeling process is executed, for example, as described above.

When the labeling process is completed, the corneal shape information acquisition unit 130 obtains the corneal shape information of the eye E to be inspected based on the positions of the five bright spot images 403A.

In this example to which the second light projection unit 42C shown in FIG. 4C is applied, the following known elliptical formula is used as in the above example to which the second light projection unit 42A shown in FIG. 4A is applied. Can: [{(x−x ₀ ) sinθ + (y−y ₀ ) cosθ} ² / a ² ] + [{(x−x ₀ ) cosθ + (y−y ₀ ) sinθ} ² / b ² ] = 1. When the center of the ellipse cannot be specified from the index in this way, the ellipse can be determined by obtaining five unknowns x ₀ , y ₀ , a, b, and θ from the coordinates of at least five points on the circumference of the ellipse.

The above processing is an example of obtaining corneal shape information based only on the captured image 400A. By the same processing, the corneal shape information can be obtained from the captured image 400B. It is also possible to obtain corneal shape information based on both the captured images 400A and 400B. This process is performed, for example, in the same manner as in the above example to which the second light projection unit 42B shown in FIG. 4B is applied.

(Positioning unit 140)
The positioning unit 140 is a moving target position of the data acquisition optical system 30 based on the two captured images acquired by the anterior segment cameras 60A and 60B and the corneal shape information obtained by the corneal shape information acquisition unit 130. To determine. The moving target position is a position representing the moving destination of the data acquisition optical system 30 in alignment.

The position-fixing unit 140 of this embodiment includes a provisional position-fixing unit 141 and a position-correcting unit 142.

(Temporary Positioning Unit 141)
A projected image of parallel light (Pulkiner image, bright spot image) formed by the first light projection unit 41 is drawn on the captured images acquired by the anterior eye camera 60A and 60B, respectively. The provisional position-fixing unit 141 is a provisional data acquisition optical system 30 based on the two Pulkinje images drawn by the first light projection unit 41 drawn on the two captured images acquired by the anterior segment cameras 60A and 60B. Find the movement target position.

The provisional movement target position is a movement target position supplied to the position correction unit 142. In other words, the provisional movement target position is a movement target position in a stage before the final movement target position is obtained by the position correction unit 142.

The provisional position-fixing unit 141 analyzes the captured image acquired by the anterior-eye unit camera 60A and searches for the Purkinje image by the first light projection unit 41. Similarly, the provisional position-fixing unit 141 analyzes the captured image acquired by the anterior-eye unit camera 60B and searches for the Purkinje image by the first light projection unit 41. When the Purkinje image by the first light projection unit 41 is detected from both captured images, the provisional position determining unit 141 obtains a provisional movement target position based on these Purkinje images. Hereinafter, an example of a series of processes for determining the provisional movement target position will be described.

The alignment control unit 111 controls the first light projection unit 41 to project parallel light onto the anterior segment Ea. As a result, a Purkinje image is formed on the optical axis of the data acquisition optical system 30. This Purkinje image is formed at a position deviated in the axial direction (Z direction) from the apex of the cornea by a distance of half the radius of curvature of the cornea. In a standard living eye, the radius of curvature of the cornea is about 7.8 to 8.0 mm, and the Purkinje image is formed at a position deviated from the apex of the cornea to the retinal side by about 3.9 to 4.0 mm. The provisional position determination unit 141 obtains a provisional movement target position with reference to standard corneal shape information. In this example, the standard value of the radius of curvature of the cornea is set to 8 mm, which is referred to.

The anterior segment Ea on which parallel light is projected is photographed substantially simultaneously by the two anterior segment cameras 60A and 60B. The two captured images acquired substantially simultaneously by the two front eye cameras 60A and 60B are corrected by the image correction unit 120 as necessary and input to the provisional position determination unit 141.

The provisional position-fixing unit 141 searches for a Purkinje image by the first light projection unit 41 by analyzing each of the two captured images. This search process includes, for example, a threshold value process related to a pixel value for detecting a pixel (high-luminance pixel) corresponding to a Purkinje image, as in the conventional case.

The provisional position determination unit 141 can obtain the position of the representative point in the image region detected as the Purkinje image. The representative point may be, for example, the center point or the center of gravity point of the image region. In this case, the provisional positioning unit 141 is configured to execute, for example, a process of finding an approximate circle or an approximate ellipse on the periphery of the image region and a process of finding the center of the approximate circle or the approximate ellipse. Alternatively, the provisional position determination unit 141 performs a process of specifying a pixel having a pixel value (luminance value) exceeding the threshold value from among the pixels in the image region, and obtains the position of the center of gravity of the specified one or more pixels. It may be configured to perform processing.

When the position of the Purkinje image in each of the two captured images acquired by the anterior segment cameras 60A and 60B is specified, the provisional position determining unit 141 obtains the provisional movement target position based on the position of these Purkinje images. .. The provisional movement target position includes, for example, a position in the X direction (X coordinate value), a position in the Y direction (Y coordinate value), and a position in the Z direction (Z coordinate value). The provisional movement target position may include any one or more of the X coordinate value, the Y coordinate value, and the Z coordinate value. Further, the provisional movement target position may be defined by using a coordinate system other than the three-dimensional Cartesian coordinate system (XYZ coordinate system).

As described above, the provisional position-fixing unit 141 identifies the Purkinje image from each of the two captured images acquired substantially at the same time. Examples of these captured images (anterior segment images) are FIGS. 5A to 5C. For example, the captured image 200A shown in FIG. 5A is an anterior segment image acquired by the anterior segment camera 60A. The provisional position determining unit 141 analyzes the captured image 200A to identify the Purkinje image 202A. Similarly, the captured image 200B is an anterior segment image acquired by the anterior segment camera 60B. The provisional position determination unit 141 analyzes the captured image 200B to identify the Purkinje image 202B.

As described above, the viewing angles of the anterior segment cameras 60A and 60B are known, and the imaging magnification is also known. The provisional position determining unit 141 is relative to the ophthalmic apparatus 1 (anterior eye cameras 60A and 60B) based on the position of the Purkinje image 202A in the captured image 200A and the position of the Purkinje image 202B in the captured image 200B. The position (three-dimensional position in real space) can be obtained. This process will be described with reference to FIG.

The distance (baseline length) between the two anterior segment cameras 60A and 60B is represented by "B". The distance (shooting distance) between the baseline connecting the two anterior segment cameras 60A and 60B and the Purkinje image P formed on the anterior segment Ea is represented by "H". Further, the distance (screen distance) between the anterior segment camera 60A and the screen plane thereof is represented by "f". Similarly, the distance between the anterior segment camera 60B and its screen plane is also represented by "f".

In such an arrangement state, the resolution of the images captured by the anterior segment cameras 60A and 60B is expressed by the following equation. Here, Δp represents the pixel resolution.

Resolution in the XY direction (planar resolution): ΔXY = H × Δp / f
Resolution in the Z direction (depth resolution): ΔZ = H × H × Δp / (B × f)

The provisional position determination unit 141 has a positional relationship (expected) shown in FIG. 3 with respect to the positions (known) of the two anterior segment cameras 60A and 60B and the positions corresponding to the Purkinje image P in the two captured images. The three-dimensional position of the Purkinje image P is calculated by applying a known trigonometry in consideration of (angle, etc.).

(Position correction unit 142)
The position correction unit 142 corrects the provisional movement target position obtained by the provisional position determination unit 141 based on the corneal shape information acquired by the cornea shape information acquisition unit 130. As a result, the movement target position, which is the processing result of the position determination unit 140, is obtained.

An example of the process executed by the position correction unit 142 will be described with reference to FIG. FIG. 6 shows three cases (1) to (3). Here, the corneal curvature radius included in the corneal shape information acquired by the corneal shape information acquisition unit 130 is represented by r, and the standard value (for example, 8 mm) of the corneal curvature radius is represented _{by "r 0".} Further, the optical axis of the data acquisition optical system 30 is indicated by the reference numeral “30a”. Reference numeral "51" is an objective lens.

The standard value does not have to be a single value, and may be an interval (that is, a range) of the value of the radius of curvature of the cornea. This section is, for example, a connected section and a closed section or an open section.

Case (1) is a case where the corneal radius of curvature r = r _{1 of the} eye E to be inspected is smaller than the standard value r _0. Alternatively, case (1) is a case where the corneal radius of curvature r = r _{1 of the} eye E to be inspected is smaller than an arbitrary value included in the standard interval. Case (2) is a case where the radius of curvature r of the cornea of the eye E to be inspected is equal to the _{standard value r 0.} Alternatively, case (2) is a case where the corneal radius of curvature r of the eye E to be inspected is included in the standard interval. Case (3) is a case where the corneal radius of curvature r = r _{2 of the} eye E to be inspected is larger than the standard value r _0. Alternatively, case (3) is a case where the corneal radius of curvature r = r _{2 of the} eye E to be inspected is larger than an arbitrary value included in the standard interval. Hereinafter, the case where the standard value r ₀ is a single value will be described, but the same processing can be executed when the standard interval is applied.

First, the standard case (2) will be described. As described above, the case (2) is a case where the radius of curvature r of the cornea of the eye E to be inspected is equal to the _{standard value r 0 (r = r 0} ). The Purkinje image formed in this case is _{indicated by "P 0} ".

The conventional alignment, based on the Purkinje image P _0, the position offset in the -Z direction by a predetermined working distance WD from the corneal vertex position L of the eye E, an objective lens 51 are arranged. At this time, under the assumption that the first distance (r _0/2) by the corneal apex from Purkinje image P ₀ in a position offset in the -Z direction of the half of the corneal curvature radius r = r ₀ is located A position deviated by the working distance WD in the −Z direction from the corneal apex position L is set as the movement target position. In this embodiment, the distance a position offset from the "r _0/2 + WD" only Purkinje image P ₀ in the -Z direction is set to the provisional movement target position.

Next, the case (1) will be described. As described above, the case (1) is a case where the corneal radius of curvature r = r _{1 of the} eye E to be inspected is smaller than the standard value r _{0 (r = r 1} <r ₀ ). The Purkinje image formed in this case is _{indicated by "P 1} ".

The conventional alignment, it does not take into account the individual differences in corneal shape, the distance "r _0/2 + WD" only from the Purkinje image P ₁ and offset in the -Z direction position is set to the moving target position. Therefore, the distance between the corneal apex position L and the objective lens 51 is longer _{than the working distance WD by ΔZ 1.} Here, ΔZ ₁ is substantially equal to “(r ₀ − r ₁ ) / 2”. In this embodiment, the distance "r _0/2 + WD" only from the Purkinje image P ₁ and offset in the -Z direction position is set to the interim movement target position.

Next, the case (3) will be described. As described above, the case (3) is a case where the corneal radius of curvature r = r _{2 of the} eye E to be inspected is larger than the standard value r _{0 (r = r 2} > r ₀ ). The Purkinje image formed in this case is _{indicated by "P 2} ".

The conventional alignment, it does not take into account the individual differences in corneal shape, the distance "r _0/2 + WD" only from the Purkinje image P ₂ has been displaced in the -Z direction position is set to the moving target position. Therefore, the distance between the corneal apex position L and the objective lens 51 is shorter _{than the working distance WD by ΔZ 2.} Here, [Delta] Z ₂ is equal to substantially _"(r 2 _-r 0) / 2". In this embodiment, the distance "r _0/2 + WD" only from the Purkinje image P ₂ has been displaced in the -Z direction position is set to the interim movement target position.

The position correction unit 142 compares the corneal shape information (corneal radius of curvature r) acquired by the corneal shape information acquisition unit 130 with the standard value r _0.

When it is determined that the radius of curvature r of the cornea _{is equal to the standard value r 0} (that is, when the case (2) is applicable), the position correction unit 142 uses the provisional movement target position (that is, the provisional movement target position obtained by the provisional position determination unit 141). no correction for distance _"r 0/2 + WD" just offset from the Purkinje image _{P 0} in the -Z direction position). That is, when it is determined that the radius of curvature r of the cornea _{is equal to the standard value r 0} , the provisional movement target position is set as the movement target position as it is. It is possible to correct the provisional movement target position according to conditions different from the corneal shape information.

When it is determined that the radius of curvature r of the cornea _{is smaller than the standard value r 0} (that is, when it corresponds to the case (1)), the position correction unit 142 determines the provisional movement target position determined by the provisional position determination unit 141. (distance _"r 0/2 + WD" only from the Purkinje image _{P 1} and offset in the -Z direction position) corrected. Specifically, the position correction unit 142 sets the position deviated by ΔZ ₁ (= (r ₀ − r ₁ ) / 2) in the + Z direction from the provisional movement target position as the movement target position. As a result, a position substantially separated from the corneal apex position L by the working distance WD is set as the movement target position.

When it is determined that the radius of curvature r of the cornea _{is larger than the standard value r 0} (that is, when the case (3) is applicable), the position correction unit 142 determines the provisional movement target position determined by the provisional position determination unit 141. (distance _"r 0/2 + WD" only from the Purkinje image _{P 2} has been displaced in the -Z direction position) corrected. Specifically, the position correcting unit _{142, ΔZ 2 (= (r 2} -r 0) / 2) from the provisional movement target position in the + Z direction by setting the offset position to the movement target position. As a result, a position substantially separated from the corneal apex position L by the working distance WD is set as the movement target position.

As described above, in the conventional alignment, an error occurs in the movement target position (particularly, the movement target position of the Z alignment) due to the individual difference in the corneal shape. Instead, the data acquisition optical system 30 can be arranged at a position separated by the working distance WD from the corneal apex position L of the eye E to be inspected.

(Pupil position acquisition unit 150)
The pupil position acquisition unit 150 searches for a pupil image by analyzing each of the two captured images acquired by the anterior segment cameras 60A and 60B. When the pupil image is detected from both captured images, the pupil position acquisition unit 150 obtains the three-dimensional position of the pupil Ep of the eye E to be inspected.

The pupil position acquisition unit 150 includes a pupil image detection unit 151 and a pupil position calculation unit 152.

(Pupil image detection unit 151)
The pupil image detection unit 151 detects an image region (pupil image) in the captured image corresponding to the pupil Ep of the eye E to be inspected by analyzing the captured image (distortion is corrected by the image correction unit 120). To do.

First, the pupil image detection unit 151 identifies the pupil image based on the distribution of the pixel values (luminance value, etc.) of the captured image. Since the pupil is generally expressed with a lower brightness than other parts, the pupil image can be specified by searching the low-brightness image region. At this time, the pupil image may be specified in consideration of the shape of the pupil. For example, a pupil image can be detected by searching an image region having a substantially circular shape and low brightness.

(Pupil position calculation unit 152)
The pupil position calculation unit 152 obtains the three-dimensional position of the pupil Ep of the eye E to be inspected based on the pupil image detected by the pupil image detection unit 151. In this example, the three-dimensional position of the pupil center of the eye E to be inspected is obtained as the three-dimensional position of the eye E to be inspected. The definition of the three-dimensional position of the eye E to be inspected is not limited to this. For example, the three-dimensional position of the eye E to be inspected can be defined by the position of an arbitrary feature point such as the center of gravity of the pupil, the center of iris, the center of gravity of the iris, and the diseased part.

The pupil position calculation unit 152 specifies the center position of the pupil image detected by the pupil image detection unit 151. Since the pupil is substantially circular as described above, the contour of the pupil image can be detected, the center position of the approximate ellipse of the contour can be specified, and this can be set as the center of the pupil. Further, the center of gravity of the pupil image may be obtained, and the position of the center of gravity may be set as the center of the pupil.

Even when other feature points are applied, it is possible to specify the position of the feature points based on the distribution of the pixel values of the captured image in the same manner as described above.

Further, the pupil position calculation unit 152 receives the image based on the positions (expected angles) of the two front eye cameras 60A and 60B, the imaging magnification, and the positions of the two pupil centers detected from the two captured images. The three-dimensional position of the center of the pupil of the eye examination E is obtained. This process can be performed in the same manner as the identification of the three-dimensional position of the Purkinje image (see FIG. 3).

The data processing unit 12 includes, for example, a processor, RAM, ROM, a hard disk drive, and the like. A computer program that causes a processor to execute the above-mentioned processing is stored in advance in a storage device such as a hard disk drive.

<motion>
The operation of the ophthalmic apparatus 1 will be described. An operation example of the ophthalmic apparatus 1 is shown in FIGS. 7A and 7B. The patient information (patient ID, patient name, etc.) of the subject is input, and the examination type (examination mode) is selected in advance. Hereinafter, the operation related to alignment will be mainly described.

(S1: Start projecting parallel light)
The alignment control unit 111 controls the first light projection unit 41 to output parallel light. As a result, parallel light is projected onto the anterior segment Ea.

Further, at this stage, the alignment control unit 111 may control the second light projection unit 42 to output non-parallel light. As a result, non-parallel light is projected onto the anterior segment Ea.

(S2: Start shooting with the anterior segment camera)
The alignment control unit 111 controls the anterior segment cameras 60A and 60B to start photographing the anterior segment Ea.

Each of the anterior segment cameras 60A and 60B repeats image acquisition at predetermined time intervals, and sequentially sends the acquired captured images to the control unit 11. The alignment control unit 111 sequentially sends a pair of captured images (anterior eye image) acquired by the anterior eye cameras 60A and 60B to the data processing unit 12.

The data processing unit 12 sequentially applies the following processing to the pair of front eye image images that are sequentially input. Although optional, the image correction unit 120 can correct the distortion of the anterior segment image based on the aberration information.

(S3: Detect Purkinje image)
The provisional position-fixing unit 141 analyzes the (distortion-corrected) anterior ocular region image in order to identify the Purkinje image based on the first light projection unit 41.

If the projection of non-parallel light has not been started by this stage, the Purkinje image based on the first light projection unit 41 is detected as a single bright spot in the anterior segment image.

On the other hand, when the projection of non-parallel light is started by this stage, the Purkinje image based on the first light projection unit 41 is detected as a bright spot located at the center position of the anterior segment image or its vicinity. .. At this time, for example, from among the plurality of indexes, based on the positional relationship of the plurality of indexes in the anterior segment image, the relative position of the image frame with respect to the predetermined position, or the relative position of the predetermined portion of the eye E to be examined with respect to the image. You may choose the Pulkinje image.

(S4: Did you succeed in detecting the Purkinje image?)
When the Purkinje image based on the first light projection unit 41 is detected from the anterior segment image (for example, when the Purkinje image is detected from both of the pair of anterior segment images) (S4: Yes), the process is step S5. Move to. In this case, the provisional position determination unit 141 can identify a representative point in the Purkinje image based on the first light projection unit 41 and determine the position.

Processing when the Purkinje image based on the first light projection unit 41 is not detected from the anterior segment image (for example, when the Purkinje image is not detected from at least one of the pair of anterior segment images) (S4: No). Goes to step S10.

(S5: Determine the provisional movement target position)
In step S4, when the Purkinje image based on the first light projection unit 41 is detected from the anterior segment image (S4: Yes), the provisional position determination unit 141 moves the provisional movement target position based on the detected Purkinje image. Ask for. In this example, the provisional positioning unit 141 is a three-dimensional image of the Pulkiner image based on the first light projection unit 41 formed on the anterior eye portion Ea based on the pair of Pulkiner images detected from the pair of anterior eye portion images. The position (X coordinate value, Y coordinate value, Z coordinate value) can be obtained. The obtained X coordinate value and Y coordinate value are used as they are for the provisional movement target position.

Further, the provisional position determining unit 141 is based on the Z coordinate value of the Purkinje image based on the first light projection unit 41, the predetermined working distance (WD), and the standard value (r ₀ ) of the predetermined corneal radius of curvature. , Obtain the Z coordinate value of the provisional movement target position (see FIG. 6). As a result, a three-dimensional coordinate value representing the provisional movement target position can be obtained.

(S6: Move the optical system to the provisional movement target position)
The alignment control unit 111 moves the optical axis of the objective lens 51 (the optical axis of the data acquisition optical system 30) to the position represented by the X coordinate value and the Y coordinate value of the provisional movement target position obtained in step S5. In addition, the first drive unit 80A is controlled.

Further, the alignment control unit 111 arranges the first drive unit 80A so as to arrange the objective lens 51 (data acquisition optical system 30) at the position represented by the Z coordinate value of the provisional movement target position obtained in step S5. Control.

(S7: Has the provisional alignment been completed?)
Steps S3 to S7 are repeatedly executed until the provisional alignment of step S6 is completed. This series of operations is repeated, for example, until the optical axis of the data acquisition optical system 30 falls within a predetermined allowable range.

When the provisional alignment in step S6 is completed (S7: Yes), the process proceeds to step S20.

(S10: Detects pupil image)
In step S4, when the Purkinje image based on the first light projection unit 41 is not detected from the anterior ocular region image (S4: No), the pupil image detection unit 1511 (distortion is corrected) in order to detect the pupil image. Analyze the anterior segment image.

(S11: Did you succeed in detecting the pupil image?)
When the pupil image is detected from the anterior segment image (for example, when the pupil image is detected from both of the pair of anterior segment images) (S11: Yes), the process proceeds to step S12.

On the other hand, when the pupil image is not detected from the anterior segment image (for example, when the pupil image is not detected from at least one of the pair of anterior segment images) (S11: No), the process proceeds to step S13. ..

(S12: Perform pupil alignment)
When the pupil image is detected from the anterior segment image (S11: Yes), the pupil position calculation unit 152 obtains the position of the pupil Ep of the eye E to be inspected based on the detected pupil image. In this example, the pupil position calculation unit 152 uses the pair of pupil images (pair of pupil centers) detected from the pair of anterior segment images to determine the three-dimensional position (X coordinate value, X coordinate value) of the pupil center of the eye E to be inspected. Y coordinate value, Z coordinate value) is obtained.

The alignment control unit 111 controls the first drive unit 80A so as to arrange the optical axis of the objective lens 51 at a position corresponding to the X coordinate value and the Y coordinate value of the pupil center obtained by the pupil position calculation unit 152. To do. Further, the alignment control unit 111 positions the objective lens 51 (data acquisition optical system) at a position corresponding to the Z coordinate value of the center of the pupil, the predetermined working distance (WD), and the standard value (r _{0) of the predetermined corneal radius of curvature.} The first drive unit 80A is controlled so as to arrange 30). When such pupil alignment is completed, the process returns to step S3.

(S13: Perform manual alignment)
When the pupil image is not detected from the anterior segment image (S11: No), the alignment mode is switched to the manual alignment mode.

In the manual alignment mode, the alignment control unit 111 captures the anterior segment image (or the observation image of the anterior segment Ea acquired by the data acquisition optical system 30 or the like) acquired by the anterior segment cameras 60A and / or 60B. , It is displayed as a moving image in real time on the display unit 91.

The user operates the operation unit 92 in order to move the data acquisition optical system 30. At this time, the alignment control unit 111 controls the first drive unit 80A according to the operation signal input from the operation unit 92. When the manual alignment is completed, the process returns to step S3.

(S20: Detect index)
When the provisional alignment in step S6 is completed (S7: Yes), the corneal shape information acquisition unit 130 analyzes the pair of captured images acquired by the anterior segment cameras 60A and 60B after the provisional alignment is completed. Then, the index based on the second light projection unit 42 is detected. At this time, the index based on the first light projection unit 41 may be further detected. Here, the captured image may be one that has been corrected by the image correction unit 120.

For example, when the captured image shown in FIG. 5A or FIG. 5B is obtained, both the index based on the first light projection unit 41 and the index based on the second light projection unit 42 can be detected. Further, when the captured image shown in FIG. 5A or FIG. 5C is obtained, only the index based on the second light projection unit 42 can be detected.

If the output of the finite distance visual target light (non-parallel light) from the second light projection unit 42 has not been started by this stage, the alignment control unit 111 controls the second light projection unit 42 and is finite. Outputs range-based target light (non-parallel light). After that, a pair of captured images acquired by the anterior segment cameras 60A and 60B are provided to the corneal shape information acquisition unit 130, and an index based on the second light projection unit 42 is detected.

(S21: Obtain corneal shape information)
The corneal shape information acquisition unit 130 obtains the corneal shape information of the eye E to be inspected based on the index detected in step S20. In this example, the corneal shape information includes the corneal radius of curvature r. However, parameters other than the corneal radius of curvature r can also be used in the following processing.

(S22: Is it necessary to correct the provisional movement target position?)
The position correction unit 142 determines whether or not correction of the provisional movement target position is necessary based on the corneal radius of curvature r calculated in step S21.

For example, the position correction unit 142 compares the radius of curvature r of the cornea of the eye E to be inspected with the standard value r ₀ (or the standard section). When the corneal radius of curvature r is _{equal to the standard value r 0} (or when the corneal radius of curvature r is included in the standard section), the position correction unit 142 determines that correction is unnecessary (S22: No). This determination result corresponds to the case (2) of FIG. If it is determined that the correction is unnecessary, the process proceeds to step S25.

On the other hand, when the corneal radius of curvature r is _{not equal to the standard value r 0} (or when the corneal radius of curvature r is not included in the standard section), the position correction unit 142 determines that correction is necessary (S22: Yes). This determination result corresponds to the case (1) or (3) of FIG. If it is determined that the correction is necessary, the process proceeds to step S23.

(S23: Calculate the correction amount)
When it is determined that correction is necessary (S22: Yes), the position correction unit 142 corrects the position (provisional movement target position) of the data acquisition optical system 30 based on the corneal radius of curvature calculated in step S21. .. As shown in FIG. 6, for example, this correction amount is “ΔZ _{1 ” in the case of the case (1) and “ΔZ 2} ” in the case of the case (3). Thereby, the final movement target position is determined.

(S24: Correct the position of the optical system)
The alignment control unit 111 controls the first drive unit 80A so as to move the data acquisition optical system 30 by the correction amount calculated in step S23. As a result, the data acquisition optical system 30 is arranged at a position separated by the working distance WD from the corneal apex position L of the eye E to be inspected.

(S25: Measurement / photographing of the eye to be inspected)
When the correction of the alignment position in step S24 is completed, the control unit 11 controls the data acquisition optical system 30 to measure the characteristics of the eye E to be inspected and / or to take an image of the eye E to be inspected. The UI control unit 112 causes the display unit 91 to display the measurement data and / or the captured image acquired by the data acquisition optical system 30. Further, the control unit 11 can store the measurement data and / or the captured image in the storage device. This completes the processing related to the operation in this example.

Instead of moving the data acquisition optical system 30 in step S24, a correction corresponding to the movement amount may be applied to the measurement result (measured value of the characteristic of the eye to be inspected E, etc.). Further, the movement of the data acquisition optical system 30 and the correction of the measurement result may be combined.

<Action / effect>
Some of the actions and effects of the ophthalmic apparatus according to the embodiment will be described.

The ophthalmic apparatus according to the embodiment includes a data acquisition optical system, a projection unit, two or more imaging units, a corneal shape information acquisition unit, and a position determination unit.

The data acquisition optical system has a configuration for acquiring data of the eye to be inspected. In the exemplary ophthalmic apparatus 1, the data acquisition optical system 30 is responsible for the function.

The projection unit has a configuration for projecting an index including at least one of a predetermined continuous pattern and a predetermined discrete pattern onto the anterior segment of the eye to be inspected. In the exemplary ophthalmic apparatus 1, the first light projection unit 41 and the second light projection unit 42 are responsible for the functions.

The two or more imaging units have a configuration for photographing the anterior segment of the eye on which the index is projected by the projection unit from different directions. In the exemplary ophthalmic apparatus 1, the anterior ocular cameras 60A and 60B are responsible for the function.

The corneal shape information acquisition unit has a configuration for obtaining corneal shape information of the eye to be inspected based on at least one of two or more first captured images acquired by two or more imaging units. In the exemplary ophthalmic apparatus 1, the corneal shape information acquisition unit 130 is responsible for the function.

The position-fixing unit has a configuration for determining the moving target position of the data acquisition optical system based on the two or more second captured images acquired by the two or more imaging units and the corneal shape information. In the exemplary ophthalmic apparatus 1, the position-fixing unit 140 is responsible for the function. The second captured image may be the same image as the first captured image, or may be an image different from the first captured image.

According to the embodiment configured in this way, the movement target position (alignment target position) of the data acquisition optical system can be determined in consideration of the shape of the cornea of the eye to be inspected. Therefore, it is possible to perform alignment with high accuracy regardless of individual differences in corneal shape.

Such an advantage seems to be particularly effective in ophthalmic devices such as tonometers and specular microscopes, which require high-precision alignment. The advantage is also effective in other types of ophthalmic devices.

In the embodiment, the pattern of the index projected by the projection unit is arbitrary. For example, in the embodiment, the projection unit may be configured to project an index of a ring pattern or a concentric pattern onto the anterior segment of the eye as an index of the continuous pattern. As an example, there is an index 203A of a concentric circle pattern shown in FIG. 5A.

Further, the projection unit may be configured to project the index of the ring pattern and the central bright spot located at the center of the ring pattern onto the anterior segment of the eye. Further, the projection unit may be configured to project the index of the concentric circle pattern and the central bright spot located at the center of the concentric circle pattern onto the anterior segment of the eye. Examples thereof include the index 203A of the concentric pattern shown in FIG. 5A and the bright spot image (Purkinje image) 202A.

In the embodiment, the projection unit is configured to project three or more bright spots arranged on a circle and a central bright spot located at the center of the circle onto the anterior eye portion as an index of a discrete pattern. May be done. As an example, there are three bright spot images 303A and bright spot image 302A shown in FIG. 5B.

In the embodiment, the projection unit may be configured to project five or more bright spots arranged on a circle onto the anterior segment of the eye as an index of the discrete pattern. As an example, there are five bright spot images 403A shown in FIG. 5C.

In an embodiment, the projection unit may be configured to project a central bright spot onto the anterior segment of the eye by projecting a luminous flux through the optical path of the data acquisition optical system. As an example, there is a first light projection unit 41 that projects a luminous flux onto the anterior segment Ea through the optical path of the data acquisition optical system 30.

In an embodiment, the projection unit may include a non-parallel light projection unit that projects non-parallel light onto the anterior segment of the eye. In the exemplary ophthalmic apparatus 1, the second light projection unit 42 is responsible for the function.

Further, the corneal shape information acquisition unit may be configured to obtain the corneal shape information at least based on the projected image of the non-parallel light drawn in the first captured image. For example, the corneal shape information acquisition unit may be configured to obtain the corneal shape information based only on the projected image of the non-parallel light drawn on the first captured image. Alternatively, the corneal shape information acquisition unit may be configured to obtain corneal shape information based on the projection image of the non-parallel light and the projection image of the parallel light drawn in the first captured image.

In an embodiment, the projection unit may include a parallel light projection unit that projects parallel light onto the anterior segment of the eye. In the exemplary ophthalmic apparatus 1, the first light projection unit 41 is responsible for the function.

Further, the position-fixing unit may include a provisional position-determining unit and a position-correcting unit.

The provisional position determining unit has a configuration for obtaining a provisional moving target position of the data acquisition optical system based on the projected images of parallel light drawn on two or more second captured images. In the exemplary ophthalmic apparatus 1, the provisional position-fixing unit 141 is responsible for the function.

The position correction unit has a configuration for correcting the provisional movement target position determined by the provisional position determination unit based on the corneal shape information acquired by the cornea shape information acquisition unit. In the exemplary ophthalmic apparatus 1, the position correction unit 142 is responsible for the function.

According to the embodiment configured in this way, alignment using a projected image (Purkinje image) of parallel light projected by the parallel light projecting unit becomes possible. In this alignment, the provisional movement target position obtained from the Purkinje image that is not affected by the alignment state in the Z direction can be corrected according to the corneal shape of the eye to be inspected. Therefore, individual differences in corneal shape do not adversely affect alignment accuracy.

The ophthalmic apparatus according to the embodiment may include a drive unit for moving the data acquisition optical system and a control unit. Here, the drive unit may be configured to move relatively between the eye to be inspected and the data acquisition optical system. In the exemplary ophthalmic apparatus 1, the first drive unit 80A and / or the second drive unit 80 is responsible for the function of the drive unit. Further, in the exemplary ophthalmic apparatus 1, the control unit 11 (particularly the alignment control unit 111) has a function of the control unit.

The control unit executes the first control of the drive unit in order to move the data acquisition optical system to the provisional movement target position determined by the provisional position determination unit.

After the first control of the drive unit, an image of the anterior segment of the eye by two or more imaging units is obtained. The corneal shape information acquisition unit obtains corneal shape information based on two or more first captured images acquired by two or more imaging units after the first control of the driving unit.

The position correction unit determines the moving target position of the data acquisition optical system based on the corneal shape information obtained from the two or more first captured images acquired after the first control of the drive unit.

In order to move the data acquisition optical system from the provisional movement target position determined by the provisional position determination unit to the movement target position determined by the position correction unit, the control unit executes the second control of the drive unit.

According to the embodiment configured in this way, the data acquisition optical system is moved to the provisional movement target position based on the Pulkinje image based on the parallel light, and then two or more anterior segment images are acquired, and these The corneal shape information of the eye to be inspected can be acquired based on the anterior segment image, and the position of the data acquisition optical system can be corrected based on the corneal shape information.

According to such a series of processing, the corneal shape information is obtained from two or more anterior ocular segment images acquired after the alignment based on the Purkinje image based on the parallel light, so that the corneal shape information can be obtained with high accuracy. It can be easily obtained.

For example, when non-parallel light is projected onto the anterior segment to acquire corneal shape information, the position and size of the projected image of this non-parallel light is the relative position (in other words, alignment) between the eye to be inspected and the imaging portion. It changes according to the state). Therefore, an error is likely to be mixed in the process of obtaining the corneal shape information from the projected image of the non-parallel light.

On the other hand, in this embodiment, after adjusting the positional relationship between the eye to be inspected and the imaged portion, two or more anterior segment images are acquired, and corneal shape information is obtained based on them. Therefore, the possibility that an error is mixed can be reduced. In addition, since the influence of the uncertainty of the positional relationship between the eye to be inspected and the imaging unit on the position of the projected image based on non-parallel light is reduced, the algorithm for calculating the corneal shape information can be simplified and the calculation can be performed. The processing time can be shortened.

In the embodiment, the provisional position-fixing unit analyzes two or more second captured images acquired by the two or more imaging units to search for a projected image of parallel light, and when the projected image of parallel light is detected, It may be configured to find a provisional movement target position.

On the other hand, when the projected image is not detected, the pupil position acquisition unit can search for the pupil image by analyzing two or more third captured images acquired by the two or more imaging units. When the pupil image is detected, the pupil position acquisition unit can obtain the three-dimensional position of the pupil of the eye to be inspected. In the exemplary ophthalmic apparatus 1, the pupil position acquisition unit 150 is responsible for the function.

The control unit can execute the third control of the drive unit in order to move the data acquisition optical system to a position corresponding to the three-dimensional position of the pupil of the eye to be inspected determined by the pupil position acquisition unit.

Further, the provisional position determining unit can search for the projected image of the parallel light again by analyzing the two or more captured images acquired by the two or more imaging units after the third control of the driving unit.

According to the embodiment configured in this way, when the Purkinje image based on the parallel light is not detected, the alignment based on the pupil can be performed and the Purkinje image based on the parallel light can be searched again. Therefore, the alignment based on the Purkinje image based on the parallel light can be performed more reliably.

The ophthalmic apparatus according to the embodiment may include an observation image acquisition unit for acquiring an observation image of the anterior eye portion and an operation unit. In the exemplary ophthalmic apparatus 1, at least one of the anterior segment cameras 60A and 60B is responsible for the function of the observation image acquisition unit. The observation image acquisition unit may be included in the data acquisition optical system 30, or may be provided coaxially with the data acquisition optical system 30. Further, in the exemplary ophthalmic apparatus 1, the operation unit 92 has the function of the operation unit.

When the pupil image is not detected by the pupil position acquisition unit, the control unit can display the observation image acquired by the observation image acquisition unit on the display means. Further, the control unit can control the drive unit according to the operation performed by the user using the operation unit. That is, the user can arbitrarily move the data acquisition optical system.

In the exemplary ophthalmic apparatus 1, the display unit 91 functions as a display means. The display means may be included in the ophthalmic apparatus or may be a peripheral device connected to the ophthalmic apparatus.

The provisional position-fixing unit can search for the projected image of the parallel light again by analyzing two or more captured images acquired by the two or more imaging units after the movement operation of the data acquisition optical system.

According to the embodiment configured in this way, if the pupil image is not found, the user can manually perform the alignment, and after the completion, the Pulkinje image based on the parallel light can be searched again. Therefore, the alignment based on the Purkinje image based on the parallel light can be performed more reliably.

The ophthalmic apparatus according to the embodiment includes a projection unit, two or more imaging units, and a corneal shape information acquisition unit. The projection unit has a configuration for projecting an index including at least one of a predetermined continuous pattern and a predetermined discrete pattern onto the anterior segment of the eye to be inspected. In the exemplary ophthalmic apparatus 1, the first light projection unit 41 and the second light projection unit 42 are responsible for the functions. The two or more photographing units are configured to photograph the anterior segment of the eye on which the index is projected by the projection system from different directions. In the exemplary ophthalmic apparatus 1, the anterior ocular cameras 60A and 60B are responsible for the function. The corneal shape information acquisition unit obtains the corneal shape information of the eye to be inspected based on one or more captured images acquired by one or more imaging units obtained by photographing the anterior eye portion from an oblique direction among the two or more imaging units. It is configured. In the exemplary ophthalmic apparatus 1, the corneal shape information acquisition unit 130 is responsible for the function. In the exemplary ophthalmic apparatus 1, both the anterior segment cameras 60A and 60B are arranged at positions where the anterior segment can be imaged from an oblique direction, but the arrangement of two or more imaging units is this. Not limited to. For example, one of two or more imaging units is arranged at a position where the anterior segment can be photographed from the front, and the other one or more imaging units are arranged at a position where the anterior segment can be photographed from an oblique direction. May be done.

According to the embodiment configured in this way, it is possible to perform anterior ocular segment imaging for acquiring corneal shape information using at least one of two or more imaging sections that can also be used for alignment and the like. it can. Therefore, it is not necessary to provide an optical system for photographing the anterior segment from the front as in the conventional case. Therefore, the configuration of the ophthalmic apparatus can be simplified and the cost can be reduced.

A computer program for realizing the processing according to the embodiment can be stored in any recording medium that can be read by a computer. Examples of the recording medium include semiconductor memories, optical disks, magneto-optical disks (CD-ROM / DVD-RAM / DVD-ROM / MO, etc.), magnetic storage media (hard disks / floppy (registered trademark) disks / ZIP, etc.), and the like. Can be used.

It is also possible to send and receive computer programs through networks such as the Internet and LAN.

The embodiments described above are merely examples for carrying out the present invention. A person who intends to carry out the present invention can make arbitrary modifications (omission, substitution, addition, etc.) within the scope of the gist of the present invention.

1 Ophthalmology device 11 Control unit 111 Alignment control unit 12 Data processing unit 130 Corneal shape information acquisition unit 140 Position determination unit 141 Temporary position determination unit 142 Position correction unit 150 Pupil position acquisition unit 30 Data acquisition optical system 41 First light projection unit 42 , 42A, 42B, 42C Second optical projection unit 60, 60A, 60B Front eye unit Camera 80A First drive unit 91 Display unit 92 Operation unit E Eye to be inspected Ea Front eye unit

Claims (12)

Data acquisition optical system for acquiring data of the eye to be inspected,
A projection unit that projects an index including at least one of a predetermined continuous pattern and a predetermined discrete pattern onto the anterior segment of the eye to be inspected.
Two or more imaging units that photograph the anterior segment on which the index is projected from different directions, and
A corneal shape information acquisition unit that obtains corneal shape information of the eye to be inspected based on at least one of two or more first captured images acquired by the two or more imaging units.
An ophthalmic apparatus including a position-determining unit that determines a moving target position of the data acquisition optical system based on two or more second captured images acquired by the two or more imaging units and the corneal shape information. The ophthalmic apparatus according to claim 1, wherein the projection unit projects an index of a ring pattern or a concentric circle pattern onto the anterior segment of the eye as an index of the continuous pattern. The ophthalmic apparatus according to claim 2, wherein the projection unit projects an index of the ring pattern and a central bright spot located at the center of the ring pattern onto the anterior eye portion. The ophthalmic apparatus according to claim 2, wherein the projection unit projects an index of the concentric pattern and a central bright spot located at the center of the concentric pattern onto the anterior segment of the eye. The projection unit is characterized in that, as an index of the discrete pattern, three or more bright spots arranged on a circle and a central bright spot located at the center of the circle are projected onto the anterior segment of the eye. The ophthalmic apparatus according to claim 1. The ophthalmic apparatus according to claim 1, wherein the projection unit projects five or more bright spots arranged on a circle onto the anterior eye portion as an index of the discrete pattern. The ophthalmologic apparatus according to any one of claims 3 to 5, wherein the projection unit projects a central bright spot onto the anterior eye portion by projecting a luminous flux through an optical path of the data acquisition optical system. .. The projection unit includes a non-parallel light projection unit that projects non-parallel light onto the anterior segment of the eye.
The corneal shape information acquisition unit according to any one of claims 1 to 7, wherein the corneal shape information acquisition unit obtains the corneal shape information at least based on a projected image of the non-parallel light drawn on the first captured image. Ophthalmic device. The projection unit includes a parallel light projection unit that projects parallel light onto the anterior segment of the eye.
The position-fixing unit
A provisional position-fixing unit that obtains a provisional movement target position of the data acquisition optical system based on the projected images of the parallel light drawn on the two or more second captured images.
The ophthalmologic apparatus according to any one of claims 1 to 8, further comprising a position correction unit that corrects the provisional movement target position based on the corneal shape information and determines the movement target position. A drive unit that moves the data acquisition optical system and
Including the control unit
The control unit executes the first control of the drive unit in order to move the data acquisition optical system to the provisional movement target position.
The corneal shape information acquisition unit obtains the corneal shape information based on the two or more first captured images acquired by the two or more imaging units after the first control.
The position correction unit determines the movement target position based on the corneal shape information, and then determines the movement target position.
The ophthalmic apparatus according to claim 9, wherein the control unit executes a second control of the drive unit in order to move the data acquisition optical system from the provisional movement target position to the movement target position. .. The provisional position determining unit analyzes the two or more second captured images, searches for a projected image of the parallel light, and when the projected image is detected, obtains the provisional movement target position.
When the projected image is not detected, the pupil image is searched by analyzing the two or more third captured images acquired by the two or more imaging units, and when the pupil image is detected, the eye to be inspected. Includes a pupil position acquisition unit that obtains the three-dimensional position of the pupil.
The control unit executes a third control of the drive unit in order to move the data acquisition optical system to a position corresponding to the three-dimensional position.
10. The provisional position determining unit is characterized in that after the third control, it analyzes two or more captured images acquired by the two or more imaging units and searches for a projected image of the parallel light again. The ophthalmic apparatus described in. An observation image acquisition unit that acquires an observation image of the anterior segment of the eye,
Including the operation unit
When the pupil image is not detected, the control unit causes the display means to display the observation image and controls the drive unit according to the operation performed by using the operation unit.
The eleventh aspect of claim 11, wherein the provisional position determining unit analyzes two or more photographed images acquired by the two or more photographing units after the operation and searches for a projected image of the parallel light again. Ophthalmic equipment.

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