JP2020110489A - Ophthalmologic apparatus, control method thereof, program, and recording medium - Google Patents

Abstract

To automatically determine optimum focus parameters for OCT scan.SOLUTION: An ophthalmologic apparatus includes an optical coherence tomography (OCT) unit, an optical member, an evaluation processing unit, and a determination processing unit. The OCT unit applies OCT scan to the ocular fundus of an eye to be examined, and constructs an image. The optical member changes a focus state of a measurement light with which the ocular fundus is irradiated in the OCT scan. The evaluation processing unit analyzes each of a plurality of images acquired by the OCT unit in correspondence with each of a plurality of mutually different focus states, and calculates an image quality evaluation value. The determination processing unit determines an optimum value of the focus parameters based on a plurality of the image quality evaluation values calculated from the plurality of images respectively.SELECTED DRAWING: Figure 4

Description

The present invention relates to an ophthalmologic apparatus, a control method therefor, a program, and a recording medium.

According to a recent study on myopia progression, the results of animal experiments show that the focus in the peripheral part of the fundus is located closer to the sclera than the retinal surface when the center of the fundus (fovea) is in focus. It has been reported that myopia may progress as the retina moves toward the back.

The methods for examining the refractive power of the eye include subjective refraction measurement and objective refraction measurement. The subjective refraction measurement is a subjective test in which the refractive power of the subject's eye is obtained in accordance with the subject's response to the target (Landolt ring or the like) presented to the subject's eye. The objective refraction measurement is an objective test in which the refractive power of the eye to be inspected is obtained according to the change in the size or shape of the image of the reflected light projected on the fundus of the eye to be inspected. A refractometer is used for objective refraction measurement.

A spectacle lens or a contact lens is used to correct the refractive error of the eyeball. The conventional general lens is intended to correct refractive error near the fovea. On the other hand, in recent years, in addition to correction of refractive error near the fovea, lenses capable of correcting refractive error around the fundus of the eye have been used to suppress myopia progression. Considering that there are individual differences in the distribution of the focus position of the fundus of the eye, in order to effectively manage the risk of myopia, the state of the focus position of the fundus of the eye from the center to the periphery of the fundus of the eye is grasped At the same time, it is considered effective to observe the morphology of the fundus of the eye.

In order to measure the focus position of the peripheral part of the fundus, the line-of-sight direction of the eye to be inspected can be moved so that the measurement light of the refractometer is irradiated to a desired position. However, the refractometer, in principle, calculates the refractive power of the entire eyeball, and it has been impossible to grasp the morphological change of the fundus oculi, which is the main change accompanying the progress of myopia. In addition, it has been difficult to measure the local refractive power of the eyeball with high resolution by the conventional technique.

JP, 2002-017676, A JP, 2009-291253, A JP, 2016-041221, A

Earl L. Smith III, Li-Fang Hung, Juan Huang, “Relative peripheral hyperopic defocus alters central refractive development in infant monkeys”, Vision Research Volume 49, Issue 19, 30 September 2009, Pages 2386-2392

An object of the present invention is to automatically determine optimum focus parameters for OCT scan.

The ophthalmologic apparatus according to the first aspect of the exemplary embodiment includes an OCT unit configured to apply an optical coherence tomography (OCT) scan to a fundus of an eye to be examined to construct an image, and the fundus irradiated to the fundus in the OCT scan. Optical member for changing the focus state of the measurement light, and an evaluation process for calculating an image quality evaluation value by analyzing each of a plurality of images acquired by the OCT unit corresponding to a plurality of different focus states. And a determination processing unit that determines the optimum value of the focus parameter based on a plurality of image quality evaluation values calculated from the plurality of images.

A second aspect of the exemplary embodiment is the ophthalmologic apparatus of the first aspect, wherein a plurality of OCT scans respectively corresponding to a plurality of mutually different focus states are applied to each of the plurality of scan lines. As described above, the evaluation processing unit further includes a first scan control unit that controls the OCT unit and the optical member, and the evaluation processing unit may include a plurality of scan lines constructed based on the plurality of OCT scans for each of the plurality of scan lines. Each of the plurality of image quality evaluation values is calculated from the two-dimensional image, and the determination processing unit determines the optimum value of the focus parameter based on the plurality of image quality evaluation values for each of the plurality of scan lines.

A third aspect of the exemplary embodiment is the ophthalmologic apparatus of the second aspect, wherein the first scan control unit is determined by the determination processing unit for each of the plurality of scan lines. The OCT unit and the optical member are controlled so that the OCT scan is applied with the optimum value.

A fourth aspect of the exemplary embodiment is the ophthalmologic apparatus of the second aspect, wherein, for any one of the plurality of scan lines, an optimum value corresponding to the scan line determined by the determination processing unit is set. The method further includes a first selection processing unit that selects one of the two-dimensional images corresponding to the scan line.

A fifth aspect of the exemplary embodiment is the ophthalmologic apparatus of the first aspect, wherein a plurality of OCT scans respectively corresponding to a plurality of different focus states are applied to each of a plurality of scan points. As described above, the evaluation processing unit further includes a second scan control unit that controls the OCT unit and the optical member, and the evaluation processing unit may include a plurality of OCT scans, each of which is constructed based on the plurality of OCT scans. A plurality of image quality evaluation values are calculated from the one-dimensional image, and the determination processing unit determines the optimum value of the focus parameter based on the plurality of image quality evaluation values for each of the plurality of scan points.

A sixth aspect of the exemplary embodiment is the ophthalmologic apparatus of the fifth aspect, wherein the first aspect represents a distribution of a plurality of optimum values respectively corresponding to the plurality of scan points determined by the determination processing unit. The method further includes a first creation processing unit that creates a map.

A seventh aspect of the exemplary embodiment is the ophthalmologic apparatus of the fifth aspect, wherein the deviation from the predetermined reference value of the optimum value corresponding to each of the plurality of scan points determined by the determination processing unit is calculated. It further includes a second creation processing unit that calculates and creates a second map that represents distributions of a plurality of deviations corresponding to the plurality of scan points.

An eighth aspect of the exemplary embodiment is the ophthalmologic apparatus of the fifth aspect, wherein an optimum value corresponding to the scan point determined by the determination processing unit is set for any of the plurality of scan points. The method further includes a second selection processing unit that selects one of the plurality of one-dimensional images corresponding to the scan point.

A ninth aspect of the exemplary embodiment is the ophthalmologic apparatus according to any one of the first to eighth aspects, wherein the determination processing unit obtains an approximate curve of at least a part of the plurality of image quality evaluation values. , The optimum value is determined from the maximum value of the approximate curve.

A tenth aspect of the exemplary embodiment is the ophthalmologic apparatus according to any one of the first to ninth aspects, wherein the optical member is arranged in the optical path of the measurement light and has a predetermined spherical degree. The first lens described above is included.

An eleventh aspect of the exemplary embodiment is the ophthalmologic apparatus of the tenth aspect, wherein the optical member is arranged in an optical path of the measurement light and includes one or more second lenses having a predetermined astigmatism. Including.

A twelfth aspect of the exemplary embodiment is an OCT unit that constructs an image by applying an optical coherence tomography (OCT) scan to a fundus of an eye to be examined, and a measurement light irradiated to the fundus in the OCT scan. A method of controlling an ophthalmologic apparatus including an optical member for changing a focus state and a processor, the method comprising: causing the OCT unit to acquire a plurality of images respectively corresponding to a plurality of focus states different from each other; The step of causing the processor to analyze each of the images to calculate the image quality evaluation value, and the step of determining the optimum value of the focus parameter based on the plurality of image quality evaluation values calculated from the plurality of images. Is executed by the processor.

A thirteenth aspect of the exemplary embodiment is a program for causing an ophthalmologic apparatus including a computer to execute the control method of the twelfth aspect.

A fourteenth aspect of the exemplary embodiment is a computer-readable non-transitory recording medium recording the program of the thirteenth aspect.

According to the exemplary embodiment, it is possible to automatically determine the optimum focus parameter for the OCT scan.

It is a schematic diagram showing an example of composition of an ophthalmologic apparatus concerning an exemplary embodiment. It is a schematic diagram showing an example of composition of an ophthalmologic apparatus concerning an exemplary embodiment. It is a schematic diagram showing an example of composition of an ophthalmologic apparatus concerning an exemplary embodiment. It is a schematic diagram showing an example of composition of an ophthalmologic apparatus concerning an exemplary embodiment. It is a schematic diagram for explaining an example of processing which an ophthalmologic apparatus concerning an example embodiment performs. 9 is a flowchart illustrating an example of operation of the ophthalmologic apparatus according to the exemplary embodiment. 9 is a flowchart illustrating an example of operation of the ophthalmologic apparatus according to the exemplary embodiment. 9 is a flowchart illustrating an example of operation of the ophthalmologic apparatus according to the exemplary embodiment. 9 is a flowchart illustrating an example of operation of the ophthalmologic apparatus according to the exemplary embodiment. FIG. 9 is a schematic diagram for explaining an example of the operation of the ophthalmologic apparatus according to the exemplary embodiment.

An ophthalmologic apparatus, a control method thereof, a program, and a recording medium according to an exemplary embodiment will be described in detail with reference to the drawings. The disclosure content of the documents cited in this specification and any other known technique can be applied to the embodiments. Unless otherwise specified, "image data" and "image" based on it are not distinguished. Further, unless otherwise specified, the “region” of the eye to be inspected and its “image” are not distinguished.

The ophthalmologic apparatus according to the exemplary embodiment can measure a fundus of a living eye by using a Fourier domain OCT (eg, swept source OCT). The type of OCT applicable to the embodiment is not limited to the swept source OCT, and may be, for example, the spectral domain OCT or the time domain OCT.

Example embodiments may be able to process images acquired by modalities other than OCT. For example, an exemplary embodiment may be able to process images acquired by any of a fundus camera, SLO, slit lamp microscope, and ophthalmic surgical microscope. An ophthalmic device according to an exemplary embodiment may include any of a fundus camera, an SLO, a slit lamp microscope, and an ophthalmic surgical microscope.

<Constitution>
The ophthalmologic apparatus 1 of the exemplary embodiment shown in FIG. 1 includes a fundus camera unit 2, an OCT unit 100, and a calculation control unit 200. The fundus camera unit 2 is provided with an optical system and a mechanism for acquiring a front image of the subject's eye. The OCT unit 100 is provided with a part of an optical system and a mechanism for performing OCT. Another part of the optical system and the mechanism for executing the OCT is provided in the fundus camera unit 2. The arithmetic and control unit 200 includes one or more processors that execute various arithmetic operations and controls. In addition to these, optional elements such as a member for supporting the subject's face (chin rest, forehead support, etc.) and a lens unit (for example, anterior segment OCT attachment) for switching the target region of OCT A unit may be provided in the ophthalmologic apparatus 1.

In the present specification, the “processor” includes, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), and a programmable logic device (eg, SPLD (Simple Dimension), programmable logic device (eg, SPLD). It means a circuit such as Programmable Logic Device, FPGA (Field Programmable Gate Array), or the like. The processor implements the functions according to the embodiments by reading and executing a program stored in a storage circuit or a storage device, for example.

<Ocular fundus camera unit 2>
The fundus camera unit 2 is provided with an optical system for photographing the fundus Ef of the eye E to be examined. The acquired image of the fundus oculi Ef (called a fundus oculi image, a fundus oculi photograph, etc.) is a front image such as an observation image, a photographed image or the like. The observation image is obtained, for example, by capturing a moving image using near infrared light, and is used for alignment, focusing, tracking, and the like. The captured image is, for example, a still image using flash light in the visible region or the infrared region.

The fundus camera unit 2 includes an illumination optical system 10 and a photographing optical system 30. The illumination optical system 10 irradiates the eye E with illumination light. The imaging optical system 30 detects return light of illumination light from the eye E to be inspected. The measurement light from the OCT unit 100 is guided to the subject's eye E through the optical path inside the fundus camera unit 2, and the return light is guided to the OCT unit 100 through the same optical path.

The light (observation illumination light) output from the observation light source 11 of the illumination optical system 10 is reflected by the concave mirror 12, passes through the condenser lens 13, passes through the visible cut filter 14, and becomes near-infrared light. Further, the observation illumination light is once focused near the photographing light source 15, reflected by the mirror 16, and passes through the relay lens system 17, the relay lens 18, the diaphragm 19, and the relay lens system 20. Then, the observation illumination light is reflected by the peripheral portion of the apertured mirror 21 (a region around the apertured portion), transmitted through the dichroic mirror 46, refracted by the objective lens 22, and illuminates the eye E (fundus Ef). To do. The return light of the observation illumination light from the eye E is refracted by the objective lens 22, passes through the dichroic mirror 46, passes through the hole formed in the central region of the perforated mirror 21, and passes through the dichroic mirror 55. , Is reflected by the mirror 32 via the photographing focusing lens 31. Further, this return light passes through the half mirror 33A, is reflected by the dichroic mirror 33, and is imaged on the light receiving surface of the image sensor 35 by the imaging lens 34. The image sensor 35 detects the returning light at a predetermined frame rate. The focus (focus position) of the photographing optical system 30 is typically adjusted so as to match the fundus Ef or the anterior segment.

The light (imaging illumination light) output from the imaging light source 15 irradiates the fundus Ef through the same path as the observation illumination light. The return light of the photographing illumination light from the eye E is guided to the dichroic mirror 33 through the same path as the return light of the observation illumination light, passes through the dichroic mirror 33, is reflected by the mirror 36, and is formed by the imaging lens 37. An image is formed on the light receiving surface of the image sensor 38.

A liquid crystal display (LCD) 39 displays a fixation target (fixation target image). A part of the light flux output from the LCD 39 is reflected by the half mirror 33A, reflected by the mirror 32, passes through the photographing focusing lens 31 and the dichroic mirror 55, and passes through the hole of the perforated mirror 21. The light flux that has passed through the hole of the perforated mirror 21 passes through the dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the fundus Ef.

By changing the display position of the fixation target image on the screen of the LCD 39, the fixation position of the eye E to be inspected by the fixation target can be changed. As an example of the fixation position, a fixation position for acquiring an image centered on the macula, a fixation position for acquiring an image centered on the optic disc, or a position between the macula and the optic disc. There are a fixation position for acquiring a central image, a fixation position for acquiring an image of a region (peripheral part of the fundus) greatly separated from the macula, and the like. A graphical user interface (GUI) or the like for designating at least one of such typical fixation positions can be provided. Further, a GUI or the like for manually moving the fixation position (display position of the fixation target) can be provided.

The configuration for presenting the fixation target capable of changing the fixation position to the eye E is not limited to the display device such as the LCD. For example, a fixation matrix in which a plurality of light emitting units (light emitting diodes and the like) are arranged in a matrix (array) can be used instead of the display device. In this case, the fixation position of the eye E to be inspected by the fixation target can be changed by selectively turning on the plurality of light emitting units. As another example, a fixation target whose fixation position can be changed can be generated by one or more movable light emitting units.

The alignment optical system 50 generates an alignment index used for alignment of the optical system with respect to the eye E to be inspected. The alignment light output from the light emitting diode (LED) 51 passes through the diaphragm 52, the diaphragm 53, and the relay lens 54, is reflected by the dichroic mirror 55, passes through the hole portion of the perforated mirror 21, and passes through the dichroic mirror 46. The light passes through and is projected onto the subject's eye E through the objective lens 22. The return light (corneal reflected light or the like) of the alignment light from the eye E is guided to the image sensor 35 through the same path as the return light of the observation illumination light. Manual alignment or automatic alignment can be performed based on the received light image (alignment index image).

Similar to the conventional method, the alignment index image of this example is composed of two bright spot images whose positions change depending on the alignment state. When the relative position between the eye E to be inspected and the optical system changes in the xy directions, the two bright spot images are integrally displaced in the xy directions. When the relative position between the eye E and the optical system changes in the z direction, the relative position (distance) between the two bright spot images changes. When the distance between the eye E to be inspected and the optical system in the z direction coincides with the predetermined working distance, the two bright spot images overlap. When the position of the eye E and the position of the optical system coincide with each other in the xy directions, two bright spot images are presented in or near the predetermined alignment target. When the distance between the eye E to be inspected and the optical system in the z direction coincides with the working distance, and the position of the eye E in the xy direction and the position of the optical system coincide with each other, the two bright spot images are overlapped and aligned. Presented in the target.

In the automatic alignment, the data processing unit 230 detects the positions of the two bright spot images, and the main control unit 211 controls the moving mechanism 150 described later based on the positional relationship between the two bright spot images and the alignment target. .. In the manual alignment, the main control unit 211 causes the display unit 241 to display two bright spot images together with the observation image of the eye E to be examined, and the user uses the operation unit 242 while referring to the displayed two bright spot images. The moving mechanism 150 is operated.

The focus optical system 60 generates a split index used for focus adjustment on the eye E to be inspected. The focus optical system 60 is moved along the optical path (illumination optical path) of the illumination optical system 10 in conjunction with the movement of the imaging focusing lens 31 along the optical path of the imaging optical system 30 (shooting optical path). The reflecting rod 67 is inserted into and removed from the illumination optical path. When the focus is adjusted, the reflecting surface of the reflecting rod 67 is tilted in the illumination optical path. The focus light output from the LED 61 passes through the relay lens 62, is split into two light beams by the split index plate 63, passes through the two-hole diaphragm 64, is reflected by the mirror 65, and is reflected by the condenser lens 66 by the reflecting rod 67. The image is once formed on the reflection surface of and reflected. Furthermore, the focus light passes through the relay lens 20, is reflected by the perforated mirror 21, passes through the dichroic mirror 46, and is projected onto the eye E to be inspected through the objective lens 22. The return light (e.g., fundus reflection light) of the focus light from the eye E is guided to the image sensor 35 through the same path as the alignment light return light. Manual focusing and auto focusing can be performed based on the received light image (split index image).

The diopter correction lenses 70 and 71 can be selectively inserted in the photographing optical path between the perforated mirror 21 and the dichroic mirror 55. The diopter correction lens 70 is a plus lens (convex lens) for correcting intense hyperopia. The diopter correction lens 71 is a minus lens (concave lens) for correcting intense myopia.

The dichroic mirror 46 combines the fundus imaging optical path and the OCT optical path (measurement arm). The dichroic mirror 46 reflects light in the wavelength band used for OCT and transmits light for fundus imaging. The measurement arm is provided with a collimator lens unit 40, a retroreflector 41, a dispersion compensation member 42, an OCT focusing lens 43, an optical scanner 44, and a relay lens 45 in this order from the OCT unit 100 side.

The retro-reflector 41 is movable in the directions indicated by the arrows in FIG. 1 (the incident direction and the outgoing direction of the measurement light LS). Thereby, the length of the measuring arm is changed. The change of the measurement arm length is used, for example, for the correction of the optical path length according to the axial length of the eye, the correction of the optical path length according to the fundus shape, the adjustment of the interference state, and the like.

The dispersion compensating member 42 works together with the dispersion compensating member 113 (described later) arranged on the reference arm so as to match the dispersion characteristic of the measurement light LS and the dispersion characteristic of the reference light LR.

The OCT focusing lens 43 is movable along the direction indicated by the arrow in FIG. 1 (optical axis of the measurement arm) in order to adjust the focus of the measurement arm. As a result, the focus state (focal position, focal length) of the measurement arm is changed. The ophthalmologic apparatus 1 may be capable of cooperatively controlling the movement of the imaging focusing lens 31, the movement of the focusing optical system 60, and the movement of the OCT focusing lens 43.

The optical scanner 44 is arranged substantially at a position optically conjugate with the pupil of the eye E to be examined. The optical scanner 44 deflects the measurement light LS guided by the measurement arm. The optical scanner 44 is a galvano scanner capable of two-dimensional scanning including, for example, a galvano mirror for scanning in the x direction and a galvano mirror for scanning in the y direction. In this case, typically, either one of the two galvanomirrors is arranged at a position optically conjugate with the pupil of the eye E to be inspected, or the pupil conjugate position is arranged between the two galvanomirrors. As a result, the OCT scan can be applied to the posterior segment of the eye E using the position in the pupil of the eye E or the vicinity thereof as the pivot, and a wide range of the fundus Ef can be scanned.

<OCT unit 100>
As illustrated in FIG. 2, the OCT unit 100 is provided with an optical system and a mechanism for applying the swept source OCT. This optical system includes an interference optical system. This interference optical system splits the light from the variable wavelength light source (wavelength swept light source) into the measurement light and the reference light, and superimposes the return light of the measurement light from the eye E and the reference light passing through the reference optical path. In addition, interference light is generated and this interference light is detected. The detection result (detection signal) obtained by the interference optical system is a signal (interference signal) representing the spectrum of the interference light, and is sent to the arithmetic and control unit 200 (image construction unit 220).

The light source unit 101 includes, for example, a near infrared tunable laser that changes the wavelength of emitted light at high speed. The light L0 output from the light source unit 101 is guided to the polarization controller 103 by the optical fiber 102 and its polarization state is adjusted. Further, the light L0 is guided to the fiber coupler 105 by the optical fiber 104 and split into the measurement light LS and the reference light LR. The optical path of the measurement light LS is called a measurement arm or the like, and the optical path of the reference light LR is called a reference arm or the like.

The reference light LR is guided to the collimator 111 by the optical fiber 110, converted into a parallel light flux, and guided to the retroreflector 114 via the optical path length correction member 112 and the dispersion compensation member 113. The optical path length correction member 112 is an optical element for matching the optical path length of the reference light LR and the optical path length of the measurement light LS. The dispersion compensating member 113 works together with the dispersion compensating member 42 arranged in the measurement arm to match the dispersion characteristics between the reference light LR and the measurement light LS. The retro-reflector 114 is movable along the optical path of the reference light LR incident on the retro-reflector 114, whereby the length of the reference arm is changed. The change of the reference arm length is used, for example, for correction of the optical path length according to the axial length of the eye, correction of the optical path length according to the shape of the fundus of the eye, adjustment of the interference state, and the like.

The reference light LR that has passed through the retroreflector 114 passes through the dispersion compensating member 113 and the optical path length correcting member 112, is converted by the collimator 116 from a parallel light beam into a focused light beam, and enters the optical fiber 117. The reference light LR that has entered the optical fiber 117 is guided to the polarization controller 118 and its polarization state is adjusted. The polarization controller 118 is an optical member for adjusting the interference state, and is used, for example, to optimize the interference intensity between the measurement light LS and the reference light LR. The reference light LR that has passed through the polarization controller 118 is guided to the attenuator 120 through the optical fiber 119, the amount of light is adjusted, and guided to the fiber coupler 122 through the optical fiber 121.

On the other hand, the measurement light LS generated by the fiber coupler 105 is guided to the collimator lens unit 40 through the optical fiber 127 and converted into a parallel light flux. The measurement light LS emitted from the collimator lens unit 40 passes through the retro-reflector 41, the dispersion compensating member 42, the OCT focusing lens 43, the optical scanner 44 and the relay lens 45, is reflected by the dichroic mirror 46, and is refracted by the objective lens 22. It is projected onto the eye E to be examined. The measurement light LS is scattered/reflected at various depth positions of the eye E to be inspected. The return light of the measurement light LS from the subject's eye E travels in the same path as the outward path in the opposite direction, is guided to the fiber coupler 105, and reaches the fiber coupler 122 via the optical fiber 128.

The fiber coupler 122 superimposes the measurement light LS incident via the optical fiber 128 and the reference light LR incident via the optical fiber 121 to generate interference light. The fiber coupler 122 splits the generated interference light at a predetermined splitting ratio (for example, 1:1) to generate a pair of interference light LC. The pair of interference lights LC are guided to the detector 125 through the optical fibers 123 and 124, respectively.

The detector 125 includes, for example, a balanced photodiode. The balanced photodiode has a pair of photodetectors that detect a pair of interference lights LC, and outputs a difference between a pair of detection results obtained by these. The detector 125 sends this output (detection signal) to the data acquisition system (DAQ) 130.

The data collection system 130 is supplied with the clock KC from the light source unit 101. The clock KC is generated in the light source unit 101 in synchronization with the output timing of each wavelength swept within a predetermined wavelength range by the variable wavelength light source. The light source unit 101, for example, splits the light L0 of each output wavelength to generate two split lights, optically delays one of the split lights, synthesizes the split lights, and obtains the synthesized light. The clock KC is detected and the clock KC is generated based on the detection result. The data acquisition system 130 performs sampling of the detection signal input from the detector 125 based on the clock KC. The data collection system 130 sends the result of this sampling to the arithmetic and control unit 200.

In this example, both an element for changing the measurement arm length (for example, retroreflector 41) and an element for changing the reference arm length (for example, retroreflector 114 or a reference mirror) are provided. However, only one element may be provided. Further, the element for changing the difference (optical path length difference) between the measurement arm length and the reference arm length is not limited to these, and may be any element (optical member, mechanism, etc.).

In this way, the swept source OCT splits the light from the variable wavelength light source into the measurement light and the reference light, and superimposes the return light of the measurement light from the test object with the reference light to generate interference light. This is a method of constructing an image by detecting interference light with a photodetector and performing Fourier transform or the like on the detection data collected in response to the sweep of the wavelength and the scan of the measurement light.

On the other hand, the spectral domain OCT splits light from a low coherence light source (broadband light source) into measurement light and reference light, and superimposes the return light of the measurement light from the test object with the reference light to generate interference light. , A method of constructing an image by detecting the spectral distribution of this interference light with a spectroscope and applying Fourier transform or the like to the detected spectral distribution.

That is, the swept source OCT is an OCT method that acquires the spectral distribution of interference light in time division, and the spectral domain OCT is an OCT method that acquires the spectral distribution of interference light in space division.

<Control system/Processing system>
An example of the configuration of the control system and the processing system of the ophthalmologic apparatus 1 is shown in FIGS. The control unit 210, the image construction unit 220, and the data processing unit 230 are provided in the arithmetic and control unit 200, for example. The ophthalmologic apparatus 1 may include a communication device for performing data communication with an external device. The ophthalmologic apparatus 1 may include a drive device (reader/writer) for performing a process of reading data from a recording medium and a process of writing data to the recording medium.

<Control unit 210>
The control unit 210 executes various controls. The control unit 210 includes a main control unit 211 and a storage unit 212. Further, as shown in FIG. 4, the control unit 210 of the present embodiment includes a scan control unit 213 and a focus control unit 214. These are included in the main control unit 211.

<Main control unit 211>
The main control unit 211 includes a processor and controls each element of the ophthalmologic apparatus 1 (including the elements shown in FIGS. 1 to 4 ). The main control unit 211 is realized by cooperation between hardware including a processor and control software.

The main controller 211 can operate the scan controller 213 and the focus controller 214 in a coordinated (synchronous) manner. As a result, the OCT scan and the focus adjustment are cooperatively (synchronously) executed.

Under the control of the main controller 211, the photographing focusing drive unit 31A moves the photographing focusing lens 31 arranged in the photographing optical path and the focus optical system 60 arranged in the illumination optical path. The retro-reflector (RR) drive unit 41A moves the retro-reflector 41 provided on the measurement arm under the control of the main control unit 211. The OCT focusing drive unit 43A moves the OCT focusing lens 43 arranged on the measurement arm under the control of the main control unit 211 (focus control unit 214). The optical scanner 44 provided on the measurement arm operates under the control of the main controller 211 (scan controller 213). The retro-reflector (RR) drive unit 114A moves the retro-reflector 114 arranged on the reference arm under the control of the main control unit 211. Each of the drive units described above includes an actuator such as a pulse motor that operates under the control of the main control unit 211.

The moving mechanism 150 moves at least the fundus camera unit 2 three-dimensionally, for example. In a typical example, the moving mechanism 150 includes an x stage movable in ±x directions (horizontal direction), an x moving mechanism moving the x stage, and a y stage movable in ±y directions (vertical direction). , A y moving mechanism that moves the y stage, a z stage that can move in the ±z direction (depth direction), and a z moving mechanism that moves the z stage. Each of these moving mechanisms includes an actuator such as a pulse motor that operates under the control of the main control unit 211.

<Memory unit 212>
The storage unit 212 stores various data. The data stored in the storage unit 212 includes an OCT image, a fundus image, eye information, control parameters, and the like.

The eye information includes subject information such as a patient ID and name, left/right eye identification information, electronic medical record information, and the like.

The control parameters include, for example, parameters (scan parameters) used for control of OCT scan and parameters (focus parameters) used for focus (focal position, focal length) control.

The scan parameter is a parameter indicating at least the content of control for the optical scanner 44. The scan parameter may further include a parameter indicating the content of control for the light source unit 101.

Examples of scan parameters include a parameter indicating a scan position, a parameter indicating a scan pattern, a parameter indicating a scan speed, and a parameter indicating a scan interval. The scan speed is defined as, for example, the A scan repetition rate. The scan interval is defined, for example, as an interval between adjacent A scans, that is, an array interval of scan points.

In some embodiments, montage imaging (OCT scan) can be performed. In montage imaging, OCT scan is sequentially applied to a plurality of mutually different regions of the fundus oculi Ef.

Two adjacent areas of the plurality of areas to which the montage shooting is applied may be partially common to each other. In other words, with respect to the first region and the second region located next to each other among the plurality of regions, part of the first region and part of the second region may overlap each other. This overlapping area (common area) is referred to as a margin for determining the relative position between the first area and the second area in montage (panorama synthesis), for example.

The scan parameters for montage imaging may include a parameter indicating the attributes of the entire area to which montage imaging is applied (whole area parameter). Examples of the whole area parameters include shape parameters, size parameters, and position parameters of the whole area.

Scan parameters related to montage imaging may include parameters (partial region parameters) indicating attributes of a plurality of regions, each of which is a part of the entire region. Examples of the partial area parameters include a shape parameter of each partial area, a size parameter, a position parameter, a parameter indicating an array of a plurality of partial areas, a parameter indicating an application order of the OCT scan to the plurality of partial areas, and the like.

The focus parameter is a parameter indicating the content of control for the OCT focusing drive unit 43A. Examples of focus parameters include a parameter indicating the focus position of the measurement arm, a parameter indicating the moving speed of the focus position, a parameter indicating the moving acceleration of the focus position, and the like.

The parameter indicating the focal position is, for example, a parameter indicating the position of the OCT focusing lens 43 or a parameter indicating the refractive power realized by the OCT focusing lens 43. The parameter indicating the moving speed of the focus position is, for example, a parameter indicating the moving speed of the OCT focusing lens 43. The parameter indicating the movement acceleration of the focus position is, for example, a parameter indicating the movement acceleration of the OCT focusing lens 43. The moving speed may be constant or may not be constant. The same applies to the moving acceleration.

The focus parameter may include information corresponding to each of a plurality of regions to which montage shooting is applied. For example, the focus parameter may include one or more focus positions corresponding to each partial area.

When two or more focus positions are associated with one partial area, the focus parameter may include the focus positions and information indicating a range to which each focus position is applied. The information indicating the applicable range of the focus position is expressed as, for example, information indicating two or more subsets when a plurality of B scans included in the partial area are the entire set (identification numbers of B scan lines, etc.). ..

<Scan control unit 213>
The scan control unit 213 controls the optical scanner 44 based on the scan parameter. The scan controller 213 may further control the light source unit 101. The contents of the processing executed by the scan control unit 213 will be described later. The scan control unit 213 is realized by cooperation between hardware including a processor and scan control software.

<Focus control unit 214>
The focus control unit 214 controls the OCT focusing drive unit 43A based on the focus parameter. The contents of the processing executed by the focus control unit 214 will be described later. The focus control unit 214 is realized by cooperation between hardware including a processor and focus control software.

As described below, the scan control unit 213 and the focus control unit 214 according to the present embodiment can coordinately perform the movement of the OCT focusing lens 43 and the OCT scan according to the scan parameter and the focus parameter. As a result, the ophthalmologic apparatus 1 of the present embodiment acquires a plurality of OCT images respectively corresponding to a plurality of different focus states, analyzes these OCT images, and uses new focus parameters (for example, by the OCT focusing lens 43). The value of the realized refractive power) or its distribution can be obtained.

<Image construction unit 220>
The image constructing unit 220 includes a processor and constructs OCT image data of the fundus oculi Ef based on the signal (sampling data) input from the data acquisition system 130. The OCT image data constructed by the image constructing unit 220 is one or more pieces of A-scan image data, and is typically B-scan image data (two-dimensional tomographic image data) composed of a plurality of pieces of A-scan image data.

The process of constructing OCT image data includes noise removal (noise reduction), filter processing, fast Fourier transform (FFT), and the like, similar to the conventional Fourier domain OCT. In the case of another type of OCT device, the image construction unit 220 executes a known process according to the type.

The image constructing unit 220 constructs three-dimensional data of the fundus Ef based on the signal input from the data acquisition system 130. This three-dimensional data is three-dimensional image data representing a three-dimensional area (volume) of the fundus Ef. The three-dimensional image data means image data in which the pixel position is defined by the three-dimensional coordinate system. Stack data and volume data are examples of three-dimensional image data.

Stack data is image data obtained by three-dimensionally arranging a plurality of tomographic images obtained along a plurality of scan lines based on the positional relationship of these scan lines. That is, the stack data is an image obtained by expressing a plurality of tomographic images originally defined by individual two-dimensional coordinate systems by one three-dimensional coordinate system (that is, embedding in one three-dimensional space). The data. Alternatively, the stack data is obtained by arranging a plurality of A-scan image data obtained respectively for a plurality of two-dimensionally arranged scan points (scan point array) three-dimensionally based on the positional relationship of these scan points. It is the obtained image data.

The volume data is image data in which voxels arranged three-dimensionally are used as pixels, and is also called voxel data. The volume data is constructed by applying interpolation processing, voxelization processing, or the like to the stack data.

The image construction unit 220 renders the three-dimensional image data to construct a display image. Examples of applicable rendering methods include volume rendering, surface rendering, maximum intensity projection (MIP), minimum intensity projection (MinIP), and multi-section reconstruction (MPR).

The image constructing unit 220 is capable of constructing an OCT front image (OCT en-face image) based on the three-dimensional image data. For example, the image construction unit 220 can project three-dimensional image data in the z direction (A line direction, depth direction) to construct projection data. Further, the image construction unit 220 can construct a shadowgram by projecting a part of the three-dimensional image data in the z direction.

The partial 3D image data projected to construct the shadowgram is set using, for example, segmentation. Segmentation is a process of identifying a partial area in an image. Typically, segmentation is used to identify an image area corresponding to a predetermined tissue of the fundus Ef. The segmentation is executed by, for example, the image construction unit 220 or the data processing unit 230.

The ophthalmologic apparatus 1 may be capable of performing OCT angiography (OCT-Angiography). OCT angiography is an imaging technique for constructing an image in which retinal blood vessels and choroidal blood vessels are emphasized (see, for example, Japanese Patent Publication No. 2015-515894). Generally, the fundus tissue (structure) does not change with time, but the blood flow portion inside the blood vessel changes with time. In OCT angiography, an image is generated by emphasizing a portion (blood flow signal) where such a temporal change exists. The OCT angiography is also called OCT motion contrast imaging or the like. Images acquired by OCT angiography are called angiography images, angiograms, motion contrast images, and the like.

When OCT angiography is performed, the ophthalmologic apparatus 1 repeatedly scans the same region of the fundus Ef a predetermined number of times. In the montage OCT angiography, for example, it is possible to sequentially and repeatedly apply a scan to a plurality of partial regions of the array indicated by the scan parameter in the order indicated by the scan parameter. In another example, a series of OCT scans in the order shown in the scan parameter for a plurality of partial regions of the array shown in the scan parameter can be repeated a predetermined number of times. Focus parameters can be used in conjunction with scan parameters in montage OCT angiography. For example, it is possible to sequentially and repeatedly scan a plurality of partial areas of the array indicated by the scan parameter in the order indicated by the scan parameter and in the focus state indicated by the focus parameter. In another example, a series of OCT scans in the order shown in the scan parameter and in the focus state shown in the focus parameter for a plurality of partial regions of the array shown in the scan parameter can be repeated a predetermined number of times.

The image construction unit 220 can construct a motion contrast image from the data set collected by the data collection system 130 in such a repetitive scan. This motion contrast image is an angiographic image obtained by emphasizing the temporal change of the interference signal caused by the blood flow in the fundus Ef. Typically, OCT angiography is applied to the three-dimensional region of the fundus Ef to obtain an image representing the three-dimensional distribution of blood vessels in the fundus Ef.

When the OCT angiography is performed, the image constructing unit 220 can construct arbitrary 2D angiographic image data and/or arbitrary pseudo 3D angiographic image data from the 3D angiographic image data. Is. For example, the image constructing unit 220 can construct the two-dimensional angiographic image data representing an arbitrary slice of the fundus oculi Ef by applying the multi-section reconstruction to the three-dimensional angiographic image data. Further, the image constructing unit 220 constructs a front image representing a slab of any of the superficial layer, the middle layer, and the deep layer of the retina from the three-dimensional angiographic image data, and a choroidal slab (choroidal capillary plate, etc.). It is possible to construct a frontal image representing.

The image construction unit 220 is realized by cooperation between hardware including a processor and image construction software.

<Data processing unit 230>
The data processing unit 230 includes a processor and applies various types of data processing to the image of the eye E to be inspected. For example, the data processing unit 230 is realized by cooperation between hardware including a processor and data processing software.

The data processing unit 230 can perform registration (registration) between the two images acquired for the fundus Ef. For example, the data processing unit 230 can perform registration between the three-dimensional image data acquired by OCT and the front image acquired by the fundus camera unit 2. The data processing unit 230 can also perform registration between two OCT images acquired by OCT. The data processing unit 230 can also perform registration between the two front images acquired by the fundus camera unit 2. It is also possible to apply registration to the analysis result of the OCT image and the analysis result of the front image. The registration can be performed by a known method, and includes, for example, feature point extraction and affine transformation.

As shown in FIG. 4, the data processing unit 230 of the present embodiment includes an evaluation processing unit 231, a determination processing unit 232, a selection processing unit 233, a creation processing unit 234, and a combination processing unit 235.

<Evaluation processing unit 231>
The ophthalmologic apparatus 1 of the present embodiment combines a plurality of OCT images corresponding to a plurality of different focus states by combining the movement of the focus of the measurement arm (movement of the OCT focusing lens 43) and the repeated application of the OCT scan. To get

The evaluation processing unit 231 analyzes each of the acquired OCT images and calculates an image quality evaluation value. The image quality evaluation value is an arbitrary parameter that quantitatively represents the quality of the OCT image, and may be, for example, a parameter that quantitatively represents the imaging state of the measurement light. Typically, the higher the quality of the OCT image, the larger the image quality evaluation value.

A known method of calculating an Image Quality value will be described below as an example of the method of calculating the image quality evaluation value. First, the evaluation processing unit 231 applies a predetermined analysis process (for example, segmentation) to the OCT image of the fundus Ef to generate an image region (tissue image region) corresponding to the fundus tissue (retina, choroid, etc.), and Other image areas (non-tissue image areas) are detected. Next, the evaluation processing unit 231 generates a histogram based on the tissue image area and a histogram based on the non-tissue image. Subsequently, the evaluation processing unit 231 calculates an image quality evaluation value from the degree of overlap between these two histograms. For example, when the two histograms are completely overlapped, the image quality evaluation value=0, and when the two histograms are completely separated, the image quality evaluation value=100. An image quality evaluation value is defined.

In this way, the evaluation processing unit 231 analyzes a plurality of OCT images respectively acquired in correspondence with a plurality of different focus states to obtain a plurality of image quality evaluation values respectively corresponding to the plurality of OCT images. calculate.

<Decision processing unit 232>
The determination processing unit 232 determines the optimum value of the focus parameter based on the plurality of image quality evaluation values calculated from the plurality of OCT images by the evaluation processing unit 231.

For example, the determination processing unit 232 performs a process of obtaining an approximate curve of at least a part of the plurality of image quality evaluation values calculated by the evaluation processing unit 231, and a process of determining the optimum value of the focus parameter from the maximum value of the approximate curve. To execute. Hereinafter, an example of a series of processes for obtaining the optimum value of the focus parameter will be described.

As described above, the ophthalmologic apparatus 1 of the present embodiment corresponds to a plurality of different focus states by combining the movement of the focus of the measurement arm (movement of the OCT focusing lens 43) and the repeated application of the OCT scan. To acquire a plurality of OCT images. As a specific example of this operation, the focus control unit 214 moves the OCT focusing lens 43 in the range from −10 diopter (D) to +10D. At this time, the OCT focusing lens 43 is moved, for example, in 1D units. That is, the focus control unit 214 is -10D, -9D, -8D, -7D, -6D, -5D, -4D, -3D, -2D, -1D, 0D, 1D, 2D, 3D, 4D, 5D,. The OCT focusing lens 43 is arranged at positions (focus positions) corresponding to 6D, 7D, 8D, 9D, and 10D, respectively.

When the OCT focusing lens 43 is arranged at each of these focus positions, the scan control unit 213 executes an OCT scan (for example, B scan or three-dimensional scan). These OCT scans are applied to substantially the same area (for example, a two-dimensional cross section or a three-dimensional area) of the fundus Ef. As a result, 21 OCT images corresponding to these focus positions are obtained.

The evaluation processing unit 231 analyzes each of the 21 OCT images and calculates an image quality evaluation value. As a result, 21 image quality evaluation values corresponding to 21 OCT images are obtained. That is, 21 image quality evaluation values corresponding to 21 different focus positions are obtained.

The determination processing unit 232 first obtains an approximate curve of at least a part of the 21 image quality evaluation values. Typically, the determination processing unit 232 selects a plurality of image quality evaluation values from 21 image quality evaluation values according to a predetermined condition. For example, the determination processing unit 232 compares each of the 21 image quality evaluation values with a threshold value and selects an image quality evaluation value equal to or higher than the threshold value. Alternatively, the determination processing unit 232 selects a predetermined number of image quality evaluation values in order from the largest of the 21 image quality evaluation values.

Next, the determination processing unit 232 obtains an approximate curve of the plurality of selected image quality evaluation values. This approximate curve is, for example, a quadratic curve. Then, the determination processing unit 232 obtains the maximum value of this quadratic curve.

Finally, the determination processing unit 232 determines the optimum value of the focus parameter from this maximum value. For example, the determination processing unit 232 can obtain the position (diopter value or the like) of the OCT focusing lens 43 corresponding to the maximum value of the quadratic curve, and use this as the optimum value of the focus parameter. Alternatively, the decision processing unit 232 obtains a diopter value (generally a real number) corresponding to the maximum value of the quadratic curve, obtains an integer value closest to this diopter value or a decimal value of a predetermined significant digit, and calculates this. It can be adopted as the optimum value of the focus parameter.

The line graph shown in FIG. 5 is defined in a two-dimensional coordinate system with the position (diopter value) of the OCT focusing lens 43 as the horizontal axis and the image quality evaluation value as the vertical axis. That is, this line graph represents the above-mentioned 21 image quality evaluation values. Here, the plot points indicated by small diamonds have an image quality evaluation value less than a predetermined threshold value. On the other hand, the plot point indicated by a large rectangle has an image quality evaluation value equal to or greater than a predetermined threshold.

In this example, a quadratic curve approximating a plurality of plot points indicated by a large rectangle is obtained. This quadratic curve is convex upward, and typically, the maximum point (maximum value) is arranged at or near the plot point where the image quality evaluation value is the maximum. The optimum value of the focus parameter is determined based on the diopter value corresponding to this maximum point.

<Selection processing unit 233>
The selection processing unit 233 selects one OCT image from the plurality of OCT images corresponding to the plurality of focus states. An example of the processing executed by the selection processing unit 233 will be described later.

<Creation processing unit 234>
The creation processing unit 234 creates a map that represents the distribution of the optimum values of the focus parameters obtained for each of the plurality of positions of the fundus Ef. An example of the processing executed by the creation processing unit 234 will be described later.

<Synthesis processing unit 235>
The synthesis processing unit 235 constructs a synthetic image of a plurality of OCT images constructed by montage imaging. Image synthesis is performed by a known method.

When two adjacent OCT images have a common area, the synthesis processing unit 235 determines the relative position between these two OCT images by, for example, registering the images drawn in the common areas. You can decide.

When the common area is not provided, the combining processing unit 235 determines the arrangement of the plurality of OCT images corresponding to the plurality of partial areas, for example, according to the arrangement of the plurality of partial areas set by the area setting unit 231. You can

<User interface 240>
The user interface 240 includes a display unit 241 and an operation unit 242. The display unit 241 includes the display device 3. The operation unit 242 includes various operation devices and input devices. The user interface 240 may include a device having a display function and an operation function integrated, such as a touch panel. Embodiments may be constructed that do not include at least a portion of user interface 240. For example, the display device may be an external device connected to the ophthalmic device.

<motion>
Some examples of the operation of the ophthalmologic apparatus 1 will be described. Note that it is assumed that the same preparatory processing as in the past, such as the input of the patient ID, the presentation of the fixation target, the adjustment of the fixation position, the alignment, the focus adjustment, and the OCT optical path length adjustment, has already been performed.

<First operation example>
A first operation example of the ophthalmologic apparatus 1 is shown in FIG.

(S1: Move the OCT focusing lens to the initial position)
First, the focus control unit 214 controls the OCT focusing drive unit 43A so as to move the OCT focusing lens 43 to a predetermined initial position.

The initial position is a position corresponding to a focus position applied first among a plurality of focus positions which are ordered in advance. When the 21 focus positions (-10D to +10D) described above are applied, for example, "-10D" is first, "-9D" is second, and "-8D" is third. , "-7D" is the 4th, "-6D" is the 5th, "-5D" is the 6th, "-4D" is the 7th, and "-3D" is the 8th. , "-2D" is the 9th, "-1D" is the 10th, "0D" is the 11th, "1D" is the 12th, "2D" is the 13th, and "3D". Is the 14th, "4D" is the 15th, "5D" is the 16th, "6D" is the 17th, "7D" is the 18th, and "8D" is the 19th. "9D" is set to the 20th and "10D" is set to the 21st.

(S2: OCT scan applied)
After the OCT focusing lens 43 is placed at the initial position, the scan controller 213 applies the OCT scan to the fundus Ef. The image construction unit 220 constructs an OCT image from the data collected by the OCT scan.

(S3: Have all focus positions been applied?)
When all of the plurality of focus positions are applied (S3: Yes), the process proceeds to step S5. When any of the plurality of focus positions has not been applied yet (S3: No), the process proceeds to step 4.

For example, when the above-mentioned 21 focus positions (-10D to +10D) are applied, steps S1 to S4 are repeatedly executed until all 21 focus positions are applied, and when all 21 focus positions are applied. Control goes to step S5.

(S4: Change focus position)
If any one of the plurality of focus positions has not been applied yet (S3: No), the focus control unit 214 sets the OCT focusing lens 43 to a position corresponding to the focus position in the order next to the focus position applied last. The OCT focusing drive unit 43A is controlled so as to move.

For example, when the 21 focus positions (−10D to +10D) described above are applied and the last applied focus position is the kth focus position, the focus control unit 214 causes the k+1th focus position. The OCT focusing drive unit 43A is controlled to move the OCT focusing lens 43 to the position corresponding to the position (k=1 to 20).

(S5: Calculate image quality evaluation value)
When all of the plurality of focus positions are applied (S3: Yes), a plurality of OCT images respectively corresponding to the plurality of focus positions are obtained. For example, when the 21 focus positions (−10D to +10D) described above are applied and all of the 21 focus positions are applied, 21 OCT images corresponding to the 21 focus positions are obtained. To be

The evaluation processing unit 231 analyzes each of the plurality of OCT images corresponding to each of the plurality of focus positions to calculate the image quality evaluation value. Thereby, a plurality of image quality evaluation values corresponding to a plurality of focus positions are obtained.

(S6: Determine optimum value of focus parameter)
The determination processing unit 232 determines the optimum value of the focus parameter based on the plurality of image quality evaluation values obtained in step S5. For example, the determination processing unit 232 obtains an approximate curve of at least a part of the plurality of image quality evaluation values obtained in step S5, and determines the optimum value of the focus parameter from the maximum value of this approximate curve.

(S7: Move the OCT focusing lens to the position corresponding to the optimum value)
The focus control unit 214 controls the OCT focusing drive unit 43A to move the OCT focusing lens 43 to the position corresponding to the optimum value of the focus parameter determined in step S6.

(S8: OCT scan is applied at the optimum focus position)
After the focus state of the measurement arm is optimized in step S7, the scan control unit 213 applies the OCT scan to the fundus Ef. As a result, an OCT image in an optimal focus state can be obtained.

According to this operation example, it is possible to automatically search and optimize the focus state for the OCT scan.

<Second operation example>
A second operation example of the ophthalmologic apparatus 1 is shown in FIG. In this example, the OCT scan (B scan) is applied to a plurality of cross sections of the fundus oculi Ef. The pattern of the OCT scan in this example is typically any of raster scan (three-dimensional scan), radial scan, cross scan, and multi-cross scan.

The scan pattern applied in this example is preset. The scan pattern includes a plurality of pre-ordered scan lines. The plurality of scan lines correspond to the plurality of cross sections.

(S11: B scan target is set to the initial section)
First, the scan control unit 213 sets scan parameters for applying the B scan to the first cross section (initial cross section) of the plurality of cross sections. This scan parameter includes a parameter indicating the scan position. The parameter indicating the scan position includes, for example, a parameter indicating the direction of a mirror (galvano mirror or the like) included in the optical scanner 44.

(S12: Move the OCT focusing lens to the initial position)
After the target of the B scan is set to the initial cross section, the focus control unit 214 controls the OCT focusing drive unit 43A to move the OCT focusing lens 43 to a predetermined initial position. This step is executed in the same manner as step S1 of the first operation example.

(S13: OCT scan applied)
After the OCT focusing lens 43 is arranged at the initial position, the scan control unit 213 applies the OCT scan to the first cross section. The image construction unit 220 constructs an OCT image from the data collected by the OCT scan. This step is executed in the same manner as step S2 of the first operation example.

(S14: Have all focus positions been applied?)
When all of the plurality of B scans corresponding to the plurality of focus positions are applied to the first cross section (S14: Yes), the process proceeds to step S16. When the B scan corresponding to any of the plurality of focus positions has not been applied to the first cross section (S14: No), the process proceeds to step 15. This step is executed in the same manner as step S3 of the first operation example.

(S15: Change focus position)
When the B-scan corresponding to any of the plurality of focus positions is not yet applied to the first cross section (S14: No), the focus control unit 214 determines the next focus position next to the last applied focus position. The OCT focusing drive unit 43A is controlled to move the OCT focusing lens 43 to a position corresponding to the sequential focus position. This step is executed in the same manner as step S4 of the first operation example.

When all of the plurality of B-scans corresponding to the plurality of focus positions are applied to the first cross section (S14: Yes), the plurality of B-scans corresponding to the plurality of focus positions OCT image is obtained.

(S16: Have all the cross sections been scanned?)
When all of the plurality of B scans corresponding to the plurality of focus positions are applied to all the cross sections (S16: Yes), the process proceeds to step S18. Otherwise (S16: No), the process moves to step 17.

(S17: Change the cross section of the B scan target)
When the B scans at all the focus positions for all the cross sections are not yet completed (S16: No), the scan control unit 213 sets the scan parameters for applying the B scan to the cross sections in the next order. This step is executed in the same manner as step S11.

(S18: Calculate image quality evaluation value for each cross section)
When the B scans at all the focus positions for all the cross sections are completed (S16: Yes), a plurality of OCT images corresponding to the plurality of focus positions are obtained for each of the plurality of cross sections.

The evaluation processing unit 231 analyzes each of the acquired OCT images and calculates an image quality evaluation value. Thereby, a plurality of image quality evaluation values corresponding to a plurality of focus positions are obtained for each of the plurality of cross sections. This step is executed in the same manner as step S5 of the first operation example.

(S19: Determine the optimum value of the focus parameter corresponding to each cross section)
The determination processing unit 232 determines the optimum value of the focus parameter based on the plurality of image quality evaluation values obtained in step S18 for each of the plurality of cross sections. This step is executed in the same manner as step S6 of the first operation example.

(S20: B scan is applied at the optimum focus position for each cross section)
The scan control unit 213 and the focus control unit 214 apply the B scan in the optimum focus state determined in step S19 to each of the plurality of cross sections.

In this step, for example, the main control unit 211 controls the scan control unit 213 to set the scan parameters and the focus control unit 214 to optimize the focus parameters in the order set for the plurality of cross sections. And the control for causing the scan control unit 213 to perform the B scan in cooperation with each other. As a result, an OCT image in an optimal focus state can be obtained for each of the plurality of cross sections.

According to this operation example, it is possible to automatically search and optimize the focus state for the OCT scan for each of the plurality of cross sections.

<Third operation example>
A third operation example of the ophthalmologic apparatus 1 is shown in FIG. In this example, the OCT scan (B scan) is applied to a plurality of cross sections of the fundus oculi Ef, as in the second operation example. In the second operation example, the optimum focus position is obtained and the OCT scan is performed again. However, in this example, an OCT image based on the optimum focus position is selected from among the plurality of OCT images acquired to obtain the optimum focus position. select.

(S31 to S39)
Steps S31 to S39 of this example are executed in the same manner as steps S11 to S19 of the second operation example, respectively.

(S40: Select an image based on the optimum value for each cross section)
For each of the plurality of slices, the selection processing unit 233 selects one OCT image from the plurality of OCT images acquired for the slice based on the optimum value of the focus parameter corresponding to the slice.

The image selection in this step includes, for example, a process of identifying a diopter value closest to the optimum value and a process of selecting an OCT image corresponding to the identified diopter value. Alternatively, a plurality of two or more OCT images may be selected, and these OCT images may be combined (for example, arithmetic mean) to construct a single OCT image.

Thereby, a plurality of OCT images corresponding to a plurality of sections are selected.

(S41: Construct three-dimensional image from selected images of a plurality of cross sections)
The image construction unit 220 (or the data processing unit 230) constructs a three-dimensional image from a plurality of OCT images respectively corresponding to the plurality of cross sections selected in step S40. For example, the image constructing unit 220 can construct stack data by arranging a plurality of OCT images according to an array of a plurality of cross sections. Furthermore, volume data can be constructed from this stack data.

According to this operation example, it is possible to automatically search for an optimum focus state corresponding to each cross section and select an OCT image corresponding to the optimum focus state. When the OCT image is selected for each of the plurality of cross sections, it is possible to construct a three-dimensional image having a good focus state in each cross section.

<Fourth operation example>
A fourth operation example of the ophthalmologic apparatus 1 is shown in FIG. In this example, the OCT scan (B scan) is applied to a plurality of cross sections of the fundus oculi Ef, as in the second operation example. In the second operation example, the optimum focus position of each cross section is obtained and the OCT scan is performed again. However, in this example, the optimum focus position of each scan point is obtained and a map is created.

(S51 to S57)
Steps S51 to S57 of this example are executed in the same manner as steps S11 to S19 of the second operation example.

(S58: Calculate image quality evaluation value for each scan point)
When the B scans at all the focus positions for all the cross sections are completed (S56: Yes), a plurality of OCT images corresponding to the plurality of focus positions are obtained for each of the plurality of cross sections. Each of the plurality of OCT images corresponding to each cross section includes a plurality of A scan images arranged in the cross section. As an example, 21 B-scan images corresponding to mutually different diopter values are obtained for each of 256 cross-sections, and each B-scan image is formed from 256 A-scan images. The position of each A-scan image is defined by xy coordinates, and the position on the xy space indicated by the xy coordinates is the scan point.

If necessary, the data processing unit 230 registers the corresponding 21 B-scan images for each cross section. As a result, 21 A-scan images are associated with each of the 256 scan points in each cross section. The evaluation processing unit 231 calculates the image quality evaluation value of each of the 21 A-scan images.

(S59: Determine the optimum value of the focus parameter corresponding to each scan point)
The determination processing unit 232 determines the optimum value of the focus parameter based on the plurality (for example, 21) of image quality evaluation values calculated in step S58 for each scan point of each cross section.

(S60: Create focus parameter map)
The creation processing unit 234 creates a map based on the group of the optimum values of the focus parameter determined in step S59, that is, based on the optimum value of the focus parameter determined in step S59 for each scan point of each cross section. To do. The created map is information expressing the distribution of arbitrary focus parameters, and this is called a focus parameter map.

In the first example, the creation processing unit 234 can create a map showing the distribution of these optimum values based on the group of optimum values of the focus parameter determined in step S59. This focus parameter map is typically information that represents the optimal distribution of diopter values.

In the second example, the creation processing unit 234 can first calculate the deviation of each optimum value from the predetermined reference value based on the group of optimum values of the focus parameter determined in step S59. As a result, a group of deviations corresponding to the group of optimum focus parameter values is obtained. Furthermore, the creation processing unit 234 can create a map showing the distribution of these deviations based on this group of deviations. This focus parameter map is typically information representing a distribution of indices (deviations) indicating how far the optimum diopter value at each scan point deviates from a predetermined reference value. Here, the predetermined reference value may be, for example, a preset value or a value set from a group of optimum values of the focus parameter determined in step S59. Typically, a statistic (for example, average value, median value, maximum value, minimum value, etc.) obtained from a group of optimum values can be set as a reference value.

The focus parameter map is not limited to these examples, and may be information that represents the distribution of arbitrary parameters that can be calculated from the group of optimum values (and other data) of the focus parameters determined in step S59.

The expression mode of the focus parameter map is arbitrary. For example, the focus parameter map may be a map in which the magnitude of the value (for example, diopter value) in the target area of the raster scan (three-dimensional scan) is represented by contour lines. Further, the contour lines may be expressed by smooth lines (curves, straight lines, etc.) by applying smoothing processing to the contour lines. The smoothing process may include an interpolation process of interpolating the measurement points using a method such as linear interpolation or spline interpolation. The interpolation process includes, for example, a process of detecting an image region corresponding to the surface of the retinal pigment epithelium (RPE) of the fundus Ef, and a process of fitting a focus measurement point to the height profile of the image region of the RPE surface. May be included. Further, the magnitude of the value may be represented by color. For example, by dividing the entire range of value magnitudes into a plurality of sections and assigning different colors to the sections, the value magnitudes can be displayed in different colors.

According to this operation example, it is possible to create, for example, a focus parameter map in a target area of raster scan (three-dimensional scan).

<Fifth operation example>
A fifth operation example of the ophthalmologic apparatus 1 will be described. The OCT scan performed in this example is montage imaging. In the montage imaging of this example, for example, as shown in FIG. 10, the OCT scan is applied to the entire area of 9 mm×9 mm in the xy space. This entire area is divided into nine partial areas arranged in 3 rows×3 columns. The size of each partial region is 3 mm×3 mm. The numbers attached to the nine partial regions indicate the order in which the OCT scan is applied.

A common area (glue margin) is provided in the partial areas adjacent to each other so that the nine partial areas are arranged without gaps. The OCT scan for each sub-region (and the surrounding common region) is a raster scan. As shown in FIG. 10, each raster scan consists of 256 scan lines (256 B scans), and each scan line consists of 256 scan points (256 A scans).

When the montage imaging of this example is started, the ophthalmologic apparatus 1 applies the series of processes shown in steps S31 to S39 of the third operation example (FIG. 8) to the nine partial areas in the above order. As a result, the optimum focus position (the optimum value of the focus parameter) corresponding to each scan line in each partial area is determined. The information indicating the determined optimum focus position is associated with the corresponding partial area and the corresponding scan line, and is stored in, for example, the storage unit 212 or the data processing unit 230.

Further, the ophthalmologic apparatus 1 applies the raster scan to each partial area at the corresponding optimum focus position. Alternatively, the selection processing unit 233 selects an OCT image for each scan line of each partial region from the OCT image group that has already been acquired based on the optimum focus position. It is not necessary to obtain the optimum focus position for each scan line, and the optimum focus position may be obtained for each of a plurality of scan lines (for example, every two lines, every eight lines, every 16 lines).

As a result, nine three-dimensional images corresponding to the nine partial areas (obtained in a good focus state) and the optimum values of the 256 focus parameters corresponding to each of the nine partial areas (for example, , Diopter value) and. Note that instead of obtaining the optimum focus parameter value for each B scan, the optimum focus parameter value may be obtained for each A scan. In this case, for example, optimum values of 65536 (=256×256) focus parameters are obtained. The optimum value of the focus parameter may be obtained for each of the plurality of A scans.

The synthesis processing unit 235 performs registration of nine three-dimensional images based on the above-mentioned common area. Further, the composition processing unit 235 composes the nine registered three-dimensional images to construct a three-dimensional image corresponding to the entire area of 9 mm×9 mm.

Further, the creation processing unit 234 creates a focus parameter map in the entire area of 9 mm×9 mm based on the acquired optimum value group of focus parameters. This focus map is, for example, a two-dimensional contour map, and the data at each point may be subjected to a smoothing process. The smoothing process may include an interpolation process of interpolating the measurement points using a method such as linear interpolation or spline interpolation. The interpolation process may include, for example, a process of detecting an image region corresponding to the surface of the RPE of the fundus Ef, and a process of fitting a focus measurement point to the height profile of the image region of the RPE surface. A typical focus parameter map is a contour map that is color-coded for each size of the focus parameter value (diopter value or the like).

<Sixth operation example>
A sixth operation example of the ophthalmologic apparatus 1 will be described. In the fifth operation example, montage imaging is performed by dividing the entire region into a plurality of partial regions and applying a three-dimensional scan individually, but without dividing the partial region into a plurality of different focus states. It is also possible to apply a plurality of three-dimensional scans in the above to the entire region.

When the 21 focus positions (−10D to +10D) described above are applied, for example, -10D is applied in the first three-dimensional scan by the coordinated operation of the scan control unit 213 and the focus control unit 214, and the second -9D is applied in the three-dimensional scan of,..., +10D is applied in the 21st three-dimensional scan. As a result, 21 three-dimensional images corresponding to the 21 focus positions are obtained.

The data processing unit 230 performs registration of 21 three-dimensional images with any one of the 21 three-dimensional images as a reference. When the registration is completed, the data processing unit 230 divides the entire 9 mm×9 mm area into a plurality of partial areas having a predetermined size and a predetermined arrangement. For example, the size of each partial image is set to 1 mm×1 mm, and the array is set to 9 rows×9 columns. Corresponding partial images in each of the 21 three-dimensional images are associated with the plurality of partial regions. That is, 21 partial images corresponding to 21 three-dimensional images are associated with each partial region.

The evaluation processing unit 231 calculates the image quality evaluation value based on the 21 partial images associated with each partial area. As a result, 21 image quality evaluation values corresponding to each partial area are obtained. Furthermore, the determination processing unit 232 determines the optimum value of the focus parameter based on the 21 image quality evaluation values corresponding to each partial area. As a result, optimum values (for example, diopter values) of 81 focus parameters corresponding to the 81 partial areas are obtained.

The selection processing unit 233 selects, for each of the 81 partial areas, the partial image (optimal partial image) acquired at the focus position closest to the optimum value of the corresponding focus parameter from the 21 partial areas associated with the partial area. It is possible to select from the partial images. The control unit 210 can record the selection result by the selection processing unit 233.

The synthesis processing unit 235 constructs a three-dimensional image corresponding to a wider area than one partial region by synthesizing 81 optimum partial images (at least a part of them) corresponding to the 81 partial regions, respectively. be able to.

The creation processing unit 234 can create the focus parameter map based on the optimum values (at least a part thereof) of the 81 focus parameters corresponding to the 81 partial areas.

<Action/effect>
Some actions and some effects of the exemplary embodiments will be described.

An ophthalmologic apparatus according to an exemplary embodiment includes an optical coherence tomography (OCT) unit, an optical member, an evaluation processing unit, and a determination processing unit.

The OCT unit is configured to apply an OCT scan to the fundus of the eye to be inspected to construct an image. In the ophthalmologic apparatus 1 according to the exemplary embodiment, the OCT unit includes the OCT unit 100, the elements in the fundus camera unit 2 that form the measurement arm, and the image construction unit 220.

The optical member is configured to change the focus state of the measurement light irradiated on the fundus during the OCT scan. In the ophthalmologic apparatus 1 according to the exemplary embodiment, the optical member includes the OCT focusing lens 43.

The evaluation processing unit is configured to analyze each of the plurality of images acquired by the OCT unit corresponding to each of a plurality of different focus states and calculate an image quality evaluation value. In the ophthalmologic apparatus 1 according to the exemplary embodiment, the evaluation processing unit includes the evaluation processing unit 231.

The determination processing unit is configured to determine the optimum value of the focus parameter based on the plurality of image quality evaluation values calculated from the plurality of images. In the ophthalmologic apparatus 1 according to the exemplary embodiment, the decision processing unit includes the decision processing unit 232.

According to the ophthalmologic apparatus according to the exemplary embodiment, it is possible to automatically determine the optimum focus parameter based on the image quality of the plurality of OCT images actually acquired in the plurality of different focus states. Therefore, it is possible to easily acquire the optimum focus parameter for the OCT scan.

The ophthalmologic apparatus according to the exemplary embodiment may further include a first scan controller. The first scan control unit controls the OCT unit and the optical member so as to apply a plurality of OCT scans respectively corresponding to a plurality of different focus states to each of the plurality of scan lines. In the ophthalmologic apparatus 1 according to the exemplary embodiment, the first scan control unit includes the scan control unit 213.

Furthermore, the evaluation processing unit may be configured to calculate a plurality of image quality evaluation values from a plurality of two-dimensional images constructed based on a plurality of OCT scans for each of the plurality of scan lines. In addition, the determination processing unit may be configured to determine the optimum value of the focus parameter based on the plurality of image quality evaluation values for each of the plurality of scan lines.

With such a configuration, it is possible to automatically obtain the optimum focus parameter for each scan line.

In the ophthalmologic apparatus according to the exemplary embodiment, the first scan control unit may apply the OCT scan to each of the plurality of scan lines with the optimum value determined by the determination processing unit, and the optical scanning unit. It may be configured to control the member.

With this configuration, it is possible to perform the OCT scan while applying the optimum focus parameter determined for each scan line. Therefore, it is possible to easily acquire an OCT image with good image quality for each scan line.

The ophthalmologic apparatus according to the exemplary embodiment may further include a first selection processing unit. The first selection processing unit, based on the optimum value corresponding to the scan line determined by the determination processing unit for any of the plurality of scan lines, selects one of the two-dimensional images corresponding to the scan line. Select. In the ophthalmologic apparatus 1 according to the exemplary embodiment, the first selection processing unit includes the selection processing unit 233.

With such a configuration, it is possible to automatically select an OCT image having a good image quality from a plurality of OCT images acquired to determine the optimum focus parameter for each scan line. Furthermore, it is possible to construct a three-dimensional image from a plurality of OCT images of good image quality selected for a plurality of scan lines.

The ophthalmologic apparatus according to the exemplary embodiment may further include a second scan controller. The second scan control unit controls the OCT unit and the optical member so that a plurality of OCT scans respectively corresponding to a plurality of different focus states are applied to each of the plurality of scan points. In the ophthalmologic apparatus 1 according to the exemplary embodiment, the second scan control unit includes the scan control unit 213.

Furthermore, the evaluation processing unit may be configured to calculate a plurality of image quality evaluation values from a plurality of one-dimensional images constructed based on a plurality of OCT scans for each of the plurality of scan points. In addition, the determination processing section may be configured to determine the optimum value of the focus parameter based on the plurality of image quality evaluation values for each of the plurality of scan points.

With such a configuration, it is possible to automatically find the optimum focus parameter for each scan point.

The ophthalmologic apparatus according to the exemplary embodiment may further include a first creation processing unit. The first creation processing unit creates a first map that represents a distribution of a plurality of optimum values respectively corresponding to the plurality of scan points determined by the determination processing unit. In the ophthalmologic apparatus 1 according to the exemplary embodiment, the first creation processing unit includes the creation processing unit 234.

With such a configuration, it is possible to create a map that represents the optimal focus parameter distribution.

The ophthalmologic apparatus according to the exemplary embodiment may further include a second creation processing unit. The second creation processing unit calculates a deviation from the predetermined reference value of the optimum value corresponding to each of the plurality of scan points determined by the determination processing unit, and calculates a distribution of the plurality of deviations corresponding to each of the plurality of scan points. Create a second map to represent. In the ophthalmologic apparatus 1 according to the exemplary embodiment, the second creation processing unit includes the creation processing unit 234.

With such a configuration, it is possible to create a map that expresses the distribution of focus position deviations.

The ophthalmologic apparatus according to the exemplary embodiment may further include a second selection processing unit. The second selection processing unit, based on the optimum value corresponding to the scan point determined by the determination processing unit for any of the plurality of scan points, selects one of the plurality of one-dimensional images corresponding to the scan point. Select. In the ophthalmologic apparatus 1 according to the exemplary embodiment, the second selection processing unit includes the selection processing unit 233.

With such a configuration, it is possible to automatically select an OCT image having a good image quality from a plurality of OCT images acquired for determining the optimum focus parameter for each scan point. Furthermore, it is also possible to construct a two-dimensional image or a three-dimensional image from a plurality of OCT images of good image quality selected for a plurality of scan points.

In the ophthalmologic apparatus according to the exemplary embodiment, the determination processing unit performs a process of obtaining an approximate curve of at least a part of the plurality of image quality evaluation values, and a process of determining the optimum value of the focus parameter from the maximum value of the approximate curve. It may be configured to perform.

With such a configuration, it is possible to provide a specific calculation for obtaining an optimum focus parameter from a plurality of image quality evaluation values.

In the ophthalmologic apparatus according to the exemplary embodiment, the optical member may include one or more first lenses arranged in the optical path of the measurement light and having a predetermined spherical degree.

When the number of the first lenses included in the optical member is one, the focus state of the measurement arm can be changed by moving the first lens along the optical axis of the measurement arm. The ophthalmologic apparatus 1 according to the exemplary embodiment is configured to change the focus state of the measurement arm by moving the OCT focusing lens 43 along the optical axis of the measurement arm.

When the number of the first lenses included in the optical member is 2 or more, the first lenses can be selectively inserted into the measurement arm. The movement of the first lens along the optical axis may be combined with the selective insertion of the first lens.

With such a configuration, it is possible to provide a specific mode of the optical member for changing the focus state of the measurement light with which the fundus is irradiated.

In the ophthalmologic apparatus according to the exemplary embodiment, the optical member may include one or more second lenses arranged in the optical path of the measurement light and having a predetermined astigmatism. One of moving the second lens along the optical axis, rotating the second lens about the optical axis, and selectively inserting the second lens may be applied, and either of these may be applied. Two or more may be combined.

Although such a second lens is not provided in the ophthalmologic apparatus 1 according to the exemplary embodiment, for example, the second lens can be provided at a position adjacent to the OCT focusing lens 43. ..

With such a configuration, the focus state of the measurement light with which the fundus is irradiated can be changed with higher accuracy.

The exemplary embodiment provides a method of controlling an ophthalmic device. An ophthalmologic apparatus to which this control method is applied includes an OCT section, an optical member, and a processor. The OCT unit applies an OCT scan to the fundus of the eye to be inspected to construct an image. The optical member changes the focus state of the measurement light with which the fundus is irradiated in the OCT scan.

In the ophthalmologic apparatus 1 according to the exemplary embodiment, the OCT unit includes the OCT unit 100, the elements in the fundus camera unit 2 that form the measurement arm, and the image construction unit 220. The optical member includes an OCT focusing lens 43. The processor includes a control unit 210 (at least a scan control unit 213 and a focus control unit 214) and a data processing unit 230 (at least an evaluation processing unit 231 and a determination processing unit 232). This control method includes a first step, a second step, and a third step.

The first step causes the OCT section to acquire a plurality of images respectively corresponding to a plurality of different focus states. In the ophthalmologic apparatus 1 according to the exemplary embodiment, the scan control unit 213 and the focus control unit 214 execute the process of the first step.

The second step causes the processor to execute a process of analyzing each of the plurality of images and calculating an image quality evaluation value. In the ophthalmologic apparatus 1 according to the exemplary embodiment, the evaluation processing unit 231 executes the process of the second step.

The third step causes the processor to execute the process of determining the optimum value of the focus parameter based on the plurality of image quality evaluation values calculated from the plurality of images. In the ophthalmologic apparatus 1 according to the exemplary embodiment, the determination processing unit 232 executes the processing of the third step.

It is possible to combine any of the matters described in the exemplary embodiment with the control method of the ophthalmologic apparatus.

The exemplary embodiment provides a program for causing an ophthalmologic apparatus including a computer to execute such a control method. Any of the matters described in the exemplary embodiments can be combined with this program.

It is also possible to create a computer-readable non-transitory recording medium recording such a program. Any of the matters described in the exemplary embodiment can be combined with this recording medium. Further, the non-transitory recording medium may be in any form, and examples thereof include a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory and the like.

According to the control method, the program, or the recording medium according to the exemplary embodiment, the optimum focus parameter is automatically determined based on the image quality of the plurality of OCT images actually acquired in the plurality of different focus states. Is possible. Therefore, it is possible to easily acquire the optimum focus parameter for the OCT scan. In addition, the operation and effect according to the items to be combined with the control method, the program, or the recording medium according to the exemplary embodiment are exhibited.

The configuration described above is merely an example of the embodiment of the present invention. Therefore, any modification (omission, replacement, addition, etc.) within the scope of the present invention can be applied.

1 Ophthalmologic apparatus 43 OCT focusing lens 43A OCT focusing drive unit 100 OCT unit 210 control unit 213 scan control unit 214 focus control unit 220 image construction unit 230 data processing unit 231 evaluation processing unit 232 determination processing unit 233 selection processing unit 234 creation Processing unit 235 Synthesis processing unit

Claims (14)

An OCT section that constructs an image by applying optical coherence tomography (OCT) scan to the fundus of the eye to be examined;
An optical member for changing the focus state of the measurement light with which the fundus is irradiated in the OCT scan;
An evaluation processing unit that analyzes each of the plurality of images acquired by the OCT unit corresponding to a plurality of different focus states, and calculates an image quality evaluation value;
An ophthalmologic apparatus comprising: a determination processing unit that determines an optimum value of the focus parameter based on a plurality of image quality evaluation values calculated from the plurality of images. A first scan control unit that controls the OCT unit and the optical member so as to apply a plurality of OCT scans respectively corresponding to a plurality of different focus states to each of the plurality of scan lines,
The evaluation processing unit calculates, for each of the plurality of scan lines, a plurality of image quality evaluation values from a plurality of two-dimensional images constructed based on the plurality of OCT scans, respectively.
The determination processing unit determines the optimum value of the focus parameter based on the plurality of image quality evaluation values for each of the plurality of scan lines.
The ophthalmic apparatus according to claim 1. The first scan control unit controls the OCT unit and the optical member so that an OCT scan is applied to each of the plurality of scan lines at the optimum value determined by the determination processing unit,
The ophthalmologic apparatus according to claim 2. For one of the plurality of scan lines, based on the optimum value corresponding to the scan line determined by the determination processing unit, one of the plurality of two-dimensional images corresponding to the scan line is selected. Further including a selection processing unit,
The ophthalmologic apparatus according to claim 2. A second scan control unit that controls the OCT unit and the optical member so as to apply a plurality of OCT scans respectively corresponding to a plurality of different focus states to each of the plurality of scan points,
The evaluation processing unit calculates, for each of the plurality of scan points, a plurality of image quality evaluation values from a plurality of one-dimensional images constructed based on the plurality of OCT scans, respectively.
The determination processing unit determines an optimum value of the focus parameter based on the plurality of image quality evaluation values for each of the plurality of scan points.
The ophthalmic apparatus according to claim 1. The method further includes a first creation processing unit that creates a first map that represents a distribution of a plurality of optimum values respectively corresponding to the plurality of scan points determined by the determination processing unit,
The ophthalmologic apparatus according to claim 5. A second map that calculates a deviation from a predetermined reference value of an optimum value corresponding to each of the plurality of scan points determined by the determination processing unit and represents a distribution of the plurality of deviations corresponding to the plurality of scan points. Further including a second creation processing unit for creating
The ophthalmologic apparatus according to claim 5. Selecting one of the plurality of one-dimensional images corresponding to the scan point based on the optimum value corresponding to the scan point determined by the determination processing unit for any of the plurality of scan points; Further including a selection processing unit,
The ophthalmologic apparatus according to claim 5. The determination processing unit obtains an approximate curve of at least a part of the plurality of image quality evaluation values, and determines the optimum value from a maximum value of the approximate curve,
The ophthalmologic apparatus according to claim 1. The optical member is disposed in the optical path of the measurement light and includes one or more first lenses having a predetermined spherical degree,
The ophthalmologic apparatus according to claim 1. The optical member includes one or more second lenses arranged in the optical path of the measurement light and having a predetermined astigmatism.
The ophthalmologic apparatus according to claim 10. An OCT unit that applies an optical coherence tomography (OCT) scan to the fundus of the eye to be examined to construct an image, an optical member for changing the focus state of the measurement light with which the fundus is irradiated in the OCT scan, and a processor A method of controlling an ophthalmologic apparatus comprising:
Causing the OCT unit to acquire a plurality of images respectively corresponding to a plurality of different focus states,
A step of causing the processor to perform a process of calculating an image quality evaluation value by analyzing each of the plurality of images;
And a step of causing the processor to execute a process of determining an optimum value of a focus parameter based on a plurality of image quality evaluation values calculated from the plurality of images, respectively. A program that causes an ophthalmologic apparatus including a computer to execute the control method according to claim 12. A computer-readable non-transitory recording medium in which the program according to claim 13 is recorded.

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