Ophthalmological information processing device, ophthalmological device, ophthalmological information processing method, and program

Abstract

This ophthalmic information processing device comprises a generation unit, an extraction unit, and a phase correction unit. The generation unit generates a phase difference profile by performing a depth-direction averaging process on phase differences obtained by performing calculation at respective A-line depth positions between two adjacent B-frames of complex OCT data regarding an eye being examined. The extraction unit extracts a phase drift from the phase difference profile generated by the generation unit. The phase correction unit corrects the phase of first complex OCT data of one of the aforementioned two B-frames on the basis of the phase drift extracted by the extraction unit.

Description

[Technical Field]

[0001] The present invention relates to an ophthalmologic information processing device, an ophthalmologic apparatus, an ophthalmologic information processing method, and a program. [Background technology]

[0002] CAO (Computational Adaptive Optics) is a technology that uses computational processing to correct aberrations caused by the object being measured or the optical system. CAO can improve measurement accuracy by correcting measurement data based on aberration information acquired using well-known hardware such as a wavefront sensor.

[0003] For example, Non-Patent Documents 1 and 2 disclose a method of applying such CAO to an optical coherence tomography (OCT) system. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Nathan D. Shemonski et al., “Three-dimensional motion correction using speckle and phase for in vivo computed optical interferometric tomography”, BIOMEDICAL OPTICS EXPRESS, 4 NOV 2014, Vol. 5, No. 12, pp.4131-4143 [Non-patent document 2] Kensuke Oikawa et al., “Bulk phase error correction for holographic signal processing of optical coherence tomography”, Proc.SPIE11521, Biomedical Imaging and Sensing Conference 2020, 115210P(15 June 2020);doi:10.1117 / 12.2573231 Summary of the Invention [Problem to be solved by the invention]

[0005] Phase information contained in measurement data acquired by OCT is useful in applications such as OCT angiography (OCTA) and CAO-OCT, which applies CAO to OCT. This phase information is affected by phase drift due to the movement of the object being observed or phase instability within the measurement system. Therefore, the accuracy of OCTA and CAO-OCT can be improved by stabilizing the phase to avoid the effects of phase drift.

[0006] For example, it is possible to stabilize the phase by calculating the phase difference between measurement data at adjacent positions and canceling out the calculated phase difference. This is based on the assumption that the expected value of the phase difference can be assumed to be zero for a measurement object consisting of countless scatterers, such as the retina of a test eye. However, in reality, deviations / errors from this assumption exist, and as phase correction is repeated using the above method, phase errors accumulate, and the impact of these accumulated errors may become unnegligible.

[0007] The present invention has been made in view of the above circumstances, and one of its objectives is to provide a new technique for stabilizing the phase contained in measurement data acquired by OCT. [Means for solving the problem]

[0008] A first aspect of the embodiment is an ophthalmologic information processing device including: a generation unit that generates a phase difference profile by performing a depth-wise averaging process on the phase differences calculated for each depth position of an A line between two adjacent B frames of complex OCT data of a subject's eye; an extraction unit that extracts a phase drift from the phase difference profile generated by the generation unit; and a phase correction unit that corrects the phase of first complex OCT data of one of the two B frames based on the phase drift extracted by the extraction unit.

[0009] A second aspect of the embodiment is the first aspect, further comprising a removal unit that removes unreliable phase difference data from the phase difference profile, and the extraction unit extracts the phase drift from which local phase difference changes have been removed, from the phase difference profile from which the unreliable phase difference data has been removed by the removal unit.

[0010] In a third aspect of the embodiment, in the second aspect, the unreliable phase difference data includes at least one of data whose signal strength is below a predetermined threshold level and data whose contribution due to phase difference at a predetermined depth position in the averaging process exceeds a predetermined threshold.

[0011] In a fourth aspect of the embodiment, in any one of the first to third aspects, the extraction unit extracts the phase drift by performing at least one of smoothing processing, polynomial fitting, and high frequency cut filter processing on the phase difference profile.

[0012] In a fifth aspect of the embodiment, in the fourth aspect, at least one parameter of the smoothing process, the polynomial fitting, and the high frequency cut filter process is set based on at least one of the frequency of the phase change of a measurement system that acquires the complex OCT data, the speed of the phase change, and the time required for OCT scanning in the measurement system.

[0013] In a sixth aspect of the embodiment, in any of the first to fifth aspects, for adjacent first and second B frames, the phase of the complex OCT data of the second B frame is corrected based on the phase difference profile generated by the generation unit, and then for the second B frame and a third B frame adjacent to the second B frame, the phase of the complex OCT data of the third B frame is corrected based on the phase difference profile generated by the generation unit.

[0014] A seventh aspect of the embodiment is any of the first to sixth aspects, and includes an image forming unit that forms an OCT image of the test eye based on complex OCT data of the test eye in which complex OCT data of at least one B frame has been corrected by the phase correction unit.

[0015] An eighth aspect of the embodiment is an ophthalmic apparatus including a measurement system that acquires complex OCT data by performing optical coherence tomography on the subject's eye, and an ophthalmic information processing device according to any one of the first to seventh aspects.

[0016] A ninth aspect of the embodiment is an ophthalmologic information processing method including: a generation step of generating a phase difference profile by performing a depth-wise averaging process on phase differences calculated for each depth position of an A line between two adjacent B frames of complex OCT data of a subject's eye; an extraction step of extracting a phase drift from the phase difference profile generated in the generation step; and a phase correction step of correcting the phase of first complex OCT data of one of the two B frames based on the phase drift extracted in the extraction step.

[0017] A tenth aspect of the embodiment is the ninth aspect, further comprising a removal step of removing unreliable phase difference data from the phase difference profile, and the extraction step extracts the phase drift from which local phase difference changes have been removed from the phase difference profile from which the unreliable phase difference data has been removed in the removal step.

[0018] In an eleventh aspect of the embodiment, in the tenth aspect, the unreliable phase difference data includes at least one of data whose signal strength is below a predetermined threshold level and data whose contribution due to phase difference at a predetermined depth position in the averaging process exceeds a predetermined threshold.

[0019] In a twelfth aspect of the embodiment, in any of the ninth to eleventh aspects, the extraction step extracts the phase drift by performing at least one of smoothing processing, polynomial fitting, and high frequency cut filter processing on the phase difference profile.

[0020] In a thirteenth aspect of the embodiment, in the twelfth aspect, at least one parameter of the smoothing process, the polynomial fitting, and the high frequency cut filter process is set based on at least one of a frequency of a phase change of a measurement system that acquires the complex OCT data, a speed of the phase change, and a time required for an OCT scan in the measurement system.

[0021] In a fourteenth aspect of the embodiment, in any of the ninth to thirteenth aspects, for adjacent first and second B frames, the phase of the complex OCT data of the second B frame is corrected based on the phase difference profile generated in the generation step, and then for the second B frame and a third B frame adjacent to the second B frame, the phase of the complex OCT data of the third B frame is corrected based on the phase difference profile generated in the generation step.

[0022] A fifteenth aspect of the embodiment, in any of the ninth to fourteenth aspects, includes an image formation step of forming an OCT image of the test eye based on complex OCT data of the test eye in which the complex OCT data of at least one B frame has been corrected in the phase correction step.

[0023] A sixteenth aspect of the embodiment is a program for causing a computer to execute each step of the ophthalmologic information processing method according to any one of the ninth to fifteenth aspects.

[0024] The configurations according to the above-described multiple aspects can be combined in any manner. [Effects of the Invention]

[0025] According to the present invention, it is possible to provide a new technique for stabilizing the phase contained in measurement data acquired by OCT. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a schematic diagram illustrating an example of the configuration of an ophthalmologic system according to an embodiment. [Figure 2] 1 is a schematic diagram illustrating an example of the configuration of an ophthalmologic system according to an embodiment. [Figure 3] 1 is a schematic diagram illustrating an example of the configuration of an ophthalmologic system according to an embodiment. [Figure 4] 1 is a schematic diagram illustrating an example of the configuration of an optical system of an ophthalmologic apparatus according to an embodiment. [Figure 5] 1 is a schematic diagram illustrating an example of the configuration of an optical system of an ophthalmologic apparatus according to an embodiment. [Figure 6] FIG. 2 is a schematic diagram illustrating an example of the configuration of a processing system of an ophthalmologic apparatus according to an embodiment. [Figure 7] FIG. 2 is a schematic diagram for explaining a process executed by an ophthalmologic apparatus according to an embodiment. [Figure 8] FIG. 2 is a schematic diagram for explaining a process executed by an ophthalmologic apparatus according to an embodiment. [Figure 9] FIG. 2 is a schematic diagram for explaining a process executed by an ophthalmologic apparatus according to an embodiment. [Figure 10] FIG. 2 is a schematic diagram illustrating an example of the configuration of a processing system of an ophthalmologic apparatus according to an embodiment. [Figure 11] FIG. 2 is a schematic diagram illustrating an example of the configuration of a processing system of an ophthalmologic apparatus according to an embodiment. [Figure 12A] FIG. 2 is a schematic diagram for explaining a process executed by an ophthalmologic apparatus according to an embodiment. [Figure 12B]FIG. 2 is a schematic diagram for explaining a process executed by an ophthalmologic apparatus according to an embodiment. [Figure 13] FIG. 2 is a schematic diagram for explaining a process executed by an ophthalmologic apparatus according to an embodiment. [Figure 14] FIG. 2 is a schematic diagram illustrating an example of the configuration of a processing system of an ophthalmologic apparatus according to an embodiment. [Figure 15] 10 is a flowchart illustrating an example of the operation of the ophthalmologic apparatus according to the embodiment. [Figure 16] 10 is a flowchart illustrating an example of the operation of the ophthalmologic apparatus according to the embodiment. [Figure 17] 10 is a flowchart illustrating an example of the operation of the ophthalmologic apparatus according to the embodiment. [Figure 18] FIG. 2 is a schematic diagram for explaining a process executed by an ophthalmologic apparatus according to an embodiment. [Figure 19] 10 is a flowchart illustrating an example of the operation of the ophthalmologic apparatus according to the embodiment. [Figure 20] 10 is a flowchart illustrating an example of the operation of the ophthalmologic apparatus according to the embodiment. [Figure 21] 10 is a flowchart illustrating an example of the operation of the ophthalmologic apparatus according to the embodiment. [Figure 22] 10 is a flowchart illustrating an example of the operation of the ophthalmologic apparatus according to the embodiment. [Figure 23] 10 is a flowchart illustrating an example of the operation of the ophthalmologic apparatus according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0027] The following describes in detail exemplary embodiments of an ophthalmological information processing device, an ophthalmological device, an ophthalmological information processing method, a program, and a recording medium according to the present invention, with reference to the accompanying drawings. Note that the contents of documents cited in this specification and any publicly known techniques may be incorporated into the following exemplary embodiments.

[0028] An ophthalmologic information processing apparatus according to an embodiment acquires OCT data (measurement data, complex OCT data) from an external ophthalmologic apparatus (OCT apparatus). The external ophthalmologic apparatus acquires the complex OCT data by performing OCT on the subject's eye. The ophthalmologic information processing apparatus is capable of performing phase stabilization processing on the complex OCT data of the subject's eye. Specifically, the ophthalmologic information processing apparatus generates a phase difference profile by averaging the phase differences calculated for each depth position of the A-line from the complex OCT data in the depth direction, and extracts phase drift from the generated phase difference profile. The ophthalmologic information processing apparatus corrects the phase of the complex OCT data based on the extracted phase drift. At this time, the ophthalmologic information processing apparatus can remove unreliable phase difference data from the phase difference profile and extract the phase drift from the phase difference profile from which the unreliable phase difference data has been removed. This allows for the acquisition of OCT data that has undergone phase stabilization processing without being affected by noise or structural phase changes. As a result, OCT data that is robust to phase changes and phase noise caused by the movement of the subject's eye and phase instability within the OCT measurement system can be obtained.

[0029] For example, the ophthalmologic information processing device can correct aberrations caused by the subject's eye or optical system for OCT data whose phase has been corrected as described above. Specifically, the ophthalmologic information processing device searches for an optimal CAO filter (CAO filter parameters) for correcting aberrations, and performs aberration correction processing on the OCT data using the searched CAO filter. For example, if the ophthalmologic information processing device is configured to be able to acquire refractive power information representing the refractive power of the subject's eye from an external ophthalmologic device (refractive power measurement device), the ophthalmologic information processing device can calculate CAO filter parameters (filter information) based on the acquired refractive power information. The ophthalmologic information processing device can display aberration information (specifically, aberration information at the pupil plane of the subject's eye) corresponding to the searched CAO filter (parameters) on a display unit.

[0030] The ophthalmologic apparatus according to the embodiment has the functions of the ophthalmologic information processing apparatus according to the embodiment in addition to at least one of the OCT measurement function and the refractive power measurement function.

[0031] The ophthalmologic information processing method according to the embodiment includes one or more steps for implementing processing executed by a processor (computer) in the ophthalmologic information processing device according to the embodiment. The program according to the embodiment causes the processor to execute each step of the ophthalmologic information processing method according to the embodiment. The recording medium according to the embodiment is a computer-readable non-transitory recording medium (storage medium) on which the program according to the embodiment is recorded.

[0032] In this specification, the term "processor" refers to a circuit such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), or a programmable logic device (e.g., an SPLD (Simple Programmable Logic Device), a CPLD (Complex Programmable Logic Device), or an FPGA (Field Programmable Gate Array)). The processor realizes the functions according to the embodiment by, for example, reading and executing a program stored in a memory circuit or a storage device.

[0033] In the following embodiments, a case where a swept-source type OCT technique is used in measurement (or imaging) using OCT will be described in detail. However, the configuration according to the embodiment can also be applied to an ophthalmic apparatus that performs measurement using other types of OCT (for example, spectral domain type).

[0034] In this specification, images acquired by OCT may be collectively referred to as OCT images, and the measurement operation for forming an OCT image may be referred to as OCT measurement.

[0035] An ophthalmic apparatus according to some embodiments includes one or more of an ophthalmic imaging device, an ophthalmic measurement device, and an ophthalmic treatment device. The ophthalmic imaging device included in the ophthalmic apparatus according to some embodiments is, for example, one or more of a fundus camera, a scanning laser ophthalmoscope, a slit lamp ophthalmoscope, a surgical microscope, etc. The ophthalmic measurement device included in the ophthalmic apparatus according to some embodiments is, for example, one or more of an eye refraction examination device, a tonometer, a specular microscope, a wavefront analyzer, a perimeter, a microperimeter, etc. The ophthalmic treatment device included in the ophthalmic apparatus according to some embodiments is, for example, one or more of a laser treatment device, a surgical device, a surgical microscope, etc.

[0036] <Ophthalmology System> The ophthalmologic system according to the embodiment includes the functions of the ophthalmologic information processing apparatus according to the embodiment and the functions of the ophthalmologic apparatus according to the embodiment.

[0037] FIG. 1 shows a block diagram of a first configuration example of an ophthalmologic system according to an embodiment.

[0038] An ophthalmologic system 1000 according to a first configuration example of the embodiment includes an OCT device 1100 as an ophthalmologic device, a refractive power measurement device 1110 as an ophthalmologic device, an ophthalmologic information-processing device 1200, a display unit 1300, and an operation unit 1400. The ophthalmologic information-processing device 1200 may have the functions of at least one of the display unit 1300 and the operation unit 1400.

[0039] The ophthalmologic information-processing device 1200 and the OCT device 1100 are communicably connected via a wired or wireless communication path. The ophthalmologic information-processing device 1200 and the refractive power measurement device 1110 are communicably connected via a wired or wireless communication path.

[0040] The OCT device 1100 includes an OCT optical system 1101 that performs OCT (OCT measurement) on the subject's eye, and transmits complex OCT data obtained by performing the OCT to the ophthalmologic information processing device 1200. For example, the OCT optical system 1101 may have a known configuration such as that disclosed in Japanese Patent Application Laid-Open No. 2019-154985.

[0041] The refractive power measurement device 1110 includes a refractive power measurement optical system 1111 that measures the refractive power of the subject's eye, and transmits refractive power information indicating the refractive power of the subject's eye obtained by the refractive power measurement to the ophthalmologic information processing device 1200. For example, the refractive power measurement optical system 1111 may have a known configuration such as that disclosed in Japanese Patent Application Laid-Open No. 2019-154985.

[0042] The ophthalmologic information processing device 1200 generates a phase difference profile by averaging, in the depth direction, the phase differences obtained by calculating for each depth position of the A line between two adjacent B frames of complex OCT data of the subject's eye from the OCT device 1100. The ophthalmologic information processing device 1200 extracts a phase drift from the generated phase difference profile, and corrects the phase of the complex OCT data of one of the two B frames based on the extracted phase drift.

[0043] Furthermore, the ophthalmologic information-processing device 1200 searches for an optimal CAO filter (CAO filter parameters) for correcting aberrations in the phase-corrected complex OCT data, and performs aberration correction processing on the complex OCT data using the searched CAO filter. The ophthalmologic information-processing device 1200 calculates the CAO filter parameters using refractive power information (refractive power measurement results) of the subject's eye from the refractive power measurement device 1110, thereby making it possible to simplify or omit the above-mentioned CAO filter search processing.

[0044] The ophthalmologic information processing device 1200 is capable of displaying on the display unit 1300 an OCT image formed based on complex OCT data that has been subjected to aberration correction using the searched CAO filter, and aberration information at the pupil plane of the subject's eye corresponding to the searched CAO filter.

[0045] The ophthalmologic information-processing device 1200 can control the display unit 1300 and control processing executed within the device based on operation information corresponding to user operations from the operation unit 1400. For example, the ophthalmologic information-processing device 1200 changes the parameters of a CAO filter based on the operation information from the operation unit 1400 and performs aberration correction processing on complex OCT data using the CAO filter with the changed parameters. The ophthalmologic information-processing device 1200 forms an OCT image based on the complex OCT data with the aberration corrected. For example, the ophthalmologic information-processing device 1200 changes the parameters of a CAO filter based on the operation information from the operation unit 1400 and displays aberration information on the pupil plane of the subject's eye corresponding to the CAO filter with the changed parameters on the display unit 1300.

[0046] In FIG. 1, the ophthalmologic system 1000 may be configured such that the ophthalmologic information processing device 1200 acquires OCT data and refractive power information from an ophthalmologic apparatus having an OCT measurement function and a refractive power measurement function.

[0047] In some embodiments, the ophthalmological apparatus includes the functionality of an ophthalmological information processing apparatus according to an embodiment.

[0048] A block diagram of a second configuration example of the ophthalmologic system according to the embodiment is shown in Fig. 2. In Fig. 2, the same components as those in Fig. 1 are denoted by the same reference numerals, and the description thereof will be omitted where appropriate.

[0049] An ophthalmic system 1000a according to a second exemplary configuration of the embodiment includes an ophthalmic apparatus 1500a that independently realizes the functions of the ophthalmic system 1000 according to the first exemplary configuration. The ophthalmic apparatus 1500a includes an ophthalmic information processing unit 1200a, a display unit 1300, an operation unit 1400, and a measurement optical system 1600a. The measurement optical system 1600a includes an OCT optical system 1101 and a refractive power measurement optical system 1111. The ophthalmic information processing unit 1200a has the functions of the ophthalmic information processing device 1200 in FIG. 1 and controls each unit of the ophthalmic apparatus 1500a.

[0050] In FIG. 2, an ophthalmic apparatus having an OCT measurement function and the function of the ophthalmic information processing apparatus according to the embodiment may be configured to acquire refractive power information from an ophthalmic apparatus having a refractive power measurement function.

[0051] Fig. 3 shows a block diagram of a third configuration example of an ophthalmologic system according to an embodiment. In Fig. 3, the same components as those in Fig. 1 or 2 are denoted by the same reference numerals, and descriptions thereof will be omitted where appropriate.

[0052] An ophthalmologic system 1000b according to a third configuration example of the embodiment includes an ophthalmologic apparatus 1500b and a refractive power measurement apparatus 1700b. The ophthalmologic apparatus 1500b and the refractive power measurement apparatus 1700b are communicably connected via a wired or wireless communication path.

[0053] The ophthalmic apparatus 1500b includes an ophthalmic information processing unit 1200b, a display unit 1300, an operation unit 1400, and a measurement optical system 1600b. The measurement optical system 1600b includes an OCT optical system 1101. The ophthalmic information processing unit 1200b controls each unit of the ophthalmic apparatus 1500b.

[0054] The refractive power measurement device 1700b includes a refractive power measurement optical system 1111, and transmits refractive power information indicating the refractive power of the subject's eye obtained by refractive power measurement to the ophthalmic apparatus 1500b.

[0055] In FIG. 3, an ophthalmic apparatus having a refractive power measurement function and a function of the ophthalmic information processing apparatus according to the embodiment may be configured to acquire OCT data from an ophthalmic apparatus having an OCT measurement function.

[0056] The configuration and operation of the embodiment will be described below using the ophthalmologic apparatus according to the third configuration example as an example.

[0057] The ophthalmologic apparatus according to the following embodiments includes an OCT device capable of OCT measurement and a fundus camera. However, the configuration according to the following embodiments can also be incorporated into a standalone OCT device.

[0058] Furthermore, although the following description will be given mainly of an ophthalmic apparatus capable of OCT measurement of the fundus of the subject's eye, the ophthalmic apparatus according to the embodiment may also be capable of OCT measurement of the anterior segment of the subject's eye. In some embodiments, the range and measurement site of the OCT measurement are changed by moving a lens that changes the focal position of the measurement light. In some embodiments, by adding one or more attachments (objective lens, front lens, etc.), a configuration is achieved that enables OCT measurement of the fundus, OCT measurement of the anterior segment, and OCT measurement of the entire eyeball including the fundus and the anterior segment. In some embodiments, in an ophthalmic apparatus for fundus measurement, a front lens is placed between the objective lens and the subject's eye, and measurement light converted into a parallel beam is incident on the subject's eye, thereby performing OCT measurement of the anterior segment.

[0059] <Ophthalmological equipment> [composition] (optical system) 4 shows an example of the configuration of the optical system of the ophthalmologic apparatus 1500b according to the embodiment. Hereinafter, the direction of the optical axis of the objective lens 22 (the traveling direction of the measuring light LS described later) is defined as the z direction, the horizontal direction perpendicular to the z direction is defined as the x direction, and the vertical direction perpendicular to the z direction is defined as the y direction.

[0060] The ophthalmic apparatus 1500b includes a fundus camera unit 2, an OCT unit 100, and an arithmetic and control unit 200. The fundus camera unit 2 is provided with an optical system and mechanisms for acquiring a front image of the subject's eye E. The OCT unit 100 is provided with a portion of the optical system and mechanisms for performing OCT. Other portions of the optical system and mechanisms for performing OCT are provided in the fundus camera unit 2. The arithmetic and control unit 200 includes one or more processors that perform various calculations and controls. In addition to these, the ophthalmic apparatus 1500b may be provided with optional elements or units such as a member for supporting the subject's face (such as a chin rest or forehead rest) and a lens unit for switching the target region of OCT (e.g., an attachment for anterior segment OCT). In some embodiments, the lens unit is configured to be manually inserted or removed between the subject's eye E and an objective lens 22 (described later). In some embodiments, the lens unit is configured to be automatically inserted or removed between the subject's eye E and an objective lens 22 (described later) under the control of the arithmetic and control unit 200 (the control unit 210 (described later)).

[0061] (Fundus camera unit 2) The fundus camera unit 2 is provided with an optical system for photographing the fundus Ef of the subject's eye E. The acquired image of the fundus Ef (called a fundus image, fundus photograph, etc.) is a front image such as an observed image or a photographed image. The observed image is obtained by capturing a moving image using near-infrared light. The photographed image is a still image using flash light. Furthermore, the fundus camera unit 2 can photograph the anterior segment Ea of the subject's eye E to acquire a front image (anterior segment image).

[0062] The fundus camera unit 2 includes an illumination optical system 10 and an imaging optical system 30. The illumination optical system 10 irradiates illumination light onto the subject's eye E. The imaging optical system 30 detects return light of the illumination light from the subject's eye E. The measurement light from the OCT unit 100 is guided to the subject's eye E through an optical path within the fundus camera unit 2, and the return light is guided to the OCT unit 100 through the same optical path.

[0063] Light (observation illumination light) output from an observation light source 11 of an illumination optical system 10 is reflected by a reflecting mirror 12 having a curved reflecting surface, passes through a condenser lens 13, and passes through a visible light cut filter 14 to become near-infrared light. The observation illumination light is then focused near an imaging light source 15, reflected by a mirror 16, and passes through relay lenses 17 and 18, an aperture 19, and a relay lens 20. The observation illumination light is then reflected by the peripheral portion (the area surrounding the hole) of a perforated mirror 21, passes through a dichroic mirror 46, and is refracted by an objective lens 22 to illuminate the subject's eye E (fundus Ef or anterior segment Ea). Return light of the observation illumination light from the subject's eye E is refracted by the objective lens 22, passes through the dichroic mirror 46, passes through a hole formed in the central region of the perforated mirror 21, and passes through a dichroic mirror 55. The returning light that has passed through the dichroic mirror 55 passes through the photographing focusing lens 31 and is reflected by the mirror 32. The returning light further passes through the half mirror 33A, is reflected by the dichroic mirror 33, and is focused on the light receiving surface of the image sensor 35 by the condenser lens 34. The image sensor 35 detects the returning light at a predetermined frame rate. The focus of the photographing optical system 30 is adjusted to match the fundus Ef or the anterior segment Ea.

[0064] Light (photography illumination light) output from the photography light source 15 is irradiated onto the fundus oculi Ef through the same path as the observation illumination light. Return light of the photography illumination light from the subject's 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 a mirror 36, and is focused on the light receiving surface of an image sensor 38 by a condenser lens 37.

[0065] A fixation target and a visual target for visual acuity testing are displayed on an LCD (Liquid Crystal Display) 39. A portion of the light beam output from the LCD 39 is reflected by a half mirror 33A, reflected by a mirror 32, passes through a photographing focusing lens 31 and a dichroic mirror 55, and passes through a hole in the aperture mirror 21. The light beam that has passed through the hole in the aperture mirror 21 is transmitted through a dichroic mirror 46, refracted by an objective lens 22, and projected onto the fundus Ef.

[0066] The fixation position of the subject's eye E can be changed by changing the display position of the fixation target on the screen of the LCD 39. Examples of fixation positions include a fixation position for acquiring an image centered on the macula, a fixation position for acquiring an image centered on the optic disc, a fixation position for acquiring an image centered on the fundus center between the macula and the optic disc, and a fixation position for acquiring an image of a region far removed from the macula (periphery of the fundus). The ophthalmologic device 1500b according to some embodiments includes a GUI (Graphical User Interface) or the like for specifying at least one of such fixation positions. The ophthalmologic device 1500b according to some embodiments includes a GUI or the like for manually moving the fixation position (display position of the fixation target).

[0067] The configuration for presenting a movable fixation target to the subject's eye E is not limited to a display device such as an LCD. For example, a movable fixation target can be generated by selectively illuminating a plurality of light sources in a light source array (such as a light-emitting diode (LED) array). Also, a movable fixation target can be generated by one or more movable light sources.

[0068] The ophthalmologic apparatus 1500b may also be provided with one or more external fixation light sources. One of the one or more external fixation light sources can project fixation light onto the fellow eye of the subject's eye E. The projection position of the fixation light onto the fellow eye is changeable. By changing the projection position of the fixation light onto the fellow eye, the fixation position of the subject's eye E can be changed. The fixation position determined by the external fixation light source may be the same as the fixation position of the subject's eye E using the LCD 39. For example, a movable fixation target can be generated by selectively turning on multiple external fixation light sources. Furthermore, a movable fixation target can be generated by one or more movable external fixation light sources.

[0069] The alignment optical system 50 generates an alignment index used to align the optical system with the subject's eye E. Alignment light output from an LED 51 passes through apertures 52 and 53 and a relay lens 54, is reflected by a dichroic mirror 55, and passes through the hole in the aperture mirror 21. The light that passes through the hole in the aperture mirror 21 passes through a dichroic mirror 46 and is projected onto the subject's eye E by the objective lens 22. Corneal reflection light of the alignment light is guided to the image sensor 35 via 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).

[0070] The focusing optical system 60 generates a split index used for focus adjustment of the subject's eye E. The focusing optical system 60 moves along the optical path (illumination optical path) of the illumination optical system 10 in conjunction with movement of the photographing focusing lens 31 along the optical path (photographing optical path) of the photographing optical system 30. The reflecting rod 67 is insertable into and removable from the illumination optical path. When performing focus adjustment, the reflective surface of the reflecting rod 67 is tilted and positioned in the illumination optical path. The focusing light output from the LED 61 passes through the relay lens 62, is split into two beams by the split index plate 63, passes through the two-hole diaphragm 64, is reflected by the mirror 65, and is once imaged and reflected on the reflective surface of the reflecting rod 67 by the condenser lens 66. The focusing light further passes through the relay lens 20, is reflected by the aperture mirror 21, passes through the dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the fundus Ef. The fundus reflection light of the focusing light is guided to the image sensor 35 through the same path as the cornea reflection light of the alignment light. Manual focusing and autofocusing can be performed based on the received light image (split target image).

[0071] The dichroic mirror 46 combines the optical path for fundus imaging and the optical path for OCT. The dichroic mirror 46 reflects light in the wavelength band used for OCT and transmits light for fundus imaging. The OCT optical path (optical path of measurement light) is provided with a collimator lens unit 40, an optical path length changing unit 41, an optical scanner 42, an OCT focusing lens 43, a mirror 44, and a relay lens 45 in this order from the OCT unit 100 side to the dichroic mirror 46 side.

[0072] The optical path length changing unit 41 is movable in the direction of the arrow shown in Figure 4 to change the length of the OCT optical path. This change in the optical path length is used for correcting the optical path length according to the axial length of the eye, adjusting the interference state, etc. The optical path length changing unit 41 includes a corner cube and a mechanism for moving it.

[0073] The optical scanner 42 is disposed at a position optically conjugate with the pupil of the subject's eye E. The optical scanner 42 deflects the measurement light LS passing through the OCT optical path. The optical scanner 42 can deflect the measurement light LS one-dimensionally or two-dimensionally.

[0074] In the case of one-dimensional deflection, the optical scanner 42 includes a galvanometer scanner that deflects the measurement light LS in a predetermined deflection direction within a predetermined deflection angle range. In the case of two-dimensional deflection, the optical scanner 42 includes a first galvanometer scanner and a second galvanometer scanner. The first galvanometer scanner deflects the measurement light LS so as to scan the imaging site (fundus Ef or anterior segment) in a horizontal direction perpendicular to the optical axis of the OCT optical system 8, which is an optical system on a path from the interference optical system included in the OCT unit 100 described below to the objective lens 22. The second galvanometer scanner deflects the measurement light LS deflected by the first galvanometer scanner so as to scan the imaging site in a vertical direction perpendicular to the optical axis of the OCT optical system 8. Scanning modes of the measurement light LS by the optical scanner 42 include, for example, horizontal scan, vertical scan, cross scan, radial scan, circular scan, concentric scan, and spiral scan.

[0075] The OCT focusing lens 43 is moved along the optical path of the measurement light LS to adjust the focus of the OCT optical system. The OCT focusing lens 43 is movable within a movement range that includes a first lens position for positioning the focal position of the measurement light LS at or near the fundus Ef of the subject's eye E, and a second lens position for collimating the measurement light LS irradiated onto the subject's eye E. The movement of the photography focusing lens 31, the movement of the focus optical system 60, and the movement of the OCT focusing lens 43 can be controlled in a coordinated manner.

[0076] (OCT unit 100) An example of the configuration of the OCT unit 100 is shown in Fig. 5. The OCT unit 100 is provided with an optical system for performing OCT measurement (or OCT imaging) on ​​the subject's eye E. This optical system is an interference optical system that splits light from a wavelength sweep (wavelength scanning) light source into measurement light and reference light, causes return light of the measurement light from the subject's eye E to interfere with the reference light that has passed through the reference light path, thereby generating interference light, and detects this interference light. The detection result (detection signal) of the interference light by the interference optical system is an interference signal that indicates the spectrum of the interference light, and is sent to the arithmetic and control unit 200.

[0077] The light source unit 101 includes a wavelength sweep type (wavelength scanning type) light source that can sweep (scan) the wavelength of emitted light, similar to a general swept-source type ophthalmic device. The wavelength sweep type light source includes a laser light source including a resonator. The light source unit 101 changes the output wavelength over time in the near-infrared wavelength band that is invisible to the human eye.

[0078] Light L0 output from the light source unit 101 is guided by an optical fiber 102 to a polarization controller 103, where its polarization state is adjusted. The polarization controller 103 adjusts the polarization state of the light L0 guided through the optical fiber 102, for example, by applying external stress to the looped optical fiber 102.

[0079] The light L0, whose polarization state has been adjusted by the polarization controller 103, is guided by an optical fiber 104 to a fiber coupler 105, where it is split into a measurement light LS and a reference light LR.

[0080] The reference light LR is guided by an optical fiber 110 to a collimator 111, where it is converted into a parallel beam, and is then guided to an optical path length changing unit 114 via an optical path length correction member 112 and a dispersion compensation member 113. The optical path length correction member 112 acts to match the optical path length of the reference light LR with the optical path length of the measurement light LS. The dispersion compensation member 113 acts to match the dispersion characteristics between the reference light LR and the measurement light LS.

[0081] The optical path length changing unit 114 is movable in the direction of the arrow shown in FIG. 5 and changes the optical path length of the reference light LR. This movement changes the optical path length of the reference light LR. This change in optical path length is used to correct the optical path length according to the axial length of the subject's eye E, adjust the interference state, and so on. The optical path length changing unit 114 is configured to include, for example, a corner cube and a movement mechanism that moves it. In this case, the corner cube of the optical path length changing unit 114 reverses the traveling direction of the reference light LR, which has been converted into a parallel beam by the collimator 111. The optical path of the reference light LR entering the corner cube and the optical path of the reference light LR exiting the corner cube are parallel.

[0082] The reference light LR that has passed through the optical path length changing unit 114 passes through a dispersion compensation member 113 and an optical path length correction member 112, is converted from a parallel beam into a convergent beam by a collimator 116, and is then incident on an optical fiber 117. The reference light LR that has passed through the optical fiber 117 is guided to a polarization controller 118 where its polarization state is adjusted, is guided by an optical fiber 119 to an attenuator 120 where the light amount is adjusted, and is then guided by an optical fiber 121 to a fiber coupler 122.

[0083] 4 and 5, both an optical path length changer 41 for changing the length of the optical path (measurement optical path, measurement arm) of the measurement light LS and an optical path length changer 114 for changing the length of the optical path (reference optical path, reference arm) of the reference light LR are provided. However, only one of the optical path length changers 41 and 114 may be provided. It is also possible to change the difference between the reference optical path length and the measurement optical path length using optical members other than these.

[0084] On the other hand, the measurement light LS generated by the fiber coupler 105 is guided by the optical fiber 127 and collimated by the collimator lens unit 40. The collimated measurement light LS is guided to the dichroic mirror 46 via the optical path length changing unit 41, the optical scanner 42, the OCT focusing lens 43, the mirror 44, and the relay lens 45. The measurement light LS guided to the dichroic mirror 46 is reflected by the dichroic mirror 46, refracted by the objective lens 22, and irradiated onto the subject's eye E. The measurement light LS is scattered (including reflected) at various depth positions in the subject's eye E. The returning light of the measurement light LS, including such backscattered light, travels in the opposite direction along the same path as the outward path and is guided to the fiber coupler 105, and reaches the fiber coupler 122 via the optical fiber 128.

[0085] Fiber coupler 122 generates interference light by combining (causing interference between) measurement light LS incident via optical fiber 128 and reference light LR incident via optical fiber 121. Fiber coupler 122 splits the interference light between measurement light LS and reference light LR at a predetermined splitting ratio (for example, 1:1) to generate a pair of interference light LC. The pair of interference light LC emitted from fiber coupler 122 is guided to detector 125 by optical fibers 123 and 124, respectively.

[0086] The detector 125 is, for example, a balanced photodiode that has a pair of photodetectors that respectively detect a pair of interference light beams LC and outputs the difference between the detection results. The detector 125 sends the detection result (interference signal) to a DAQ (Data Acquisition System) 130. A clock KC is supplied to the DAQ 130 from the light source unit 101. The clock KC is generated in synchronization with the output timing of each wavelength swept (scanned) within a predetermined wavelength range by the wavelength swept light source in the light source unit 101. For example, the light source unit 101 optically delays one of two branched beams obtained by branching light beam L0 of each output wavelength, and then generates the clock KC based on the result of detecting the combined light. The DAQ 130 samples the detection result of the detector 125 based on the clock KC. The DAQ 130 sends the sampled detection result of the detector 125 to the arithmetic and control unit 200. For example, for each series of wavelength scans (each A-line), the arithmetic and control unit 200 forms a complex amplitude profile or a reflection intensity profile for each A-line by performing a Fourier transform or the like on the spectral distribution based on the detection results obtained by the detector 125. Furthermore, the arithmetic and control unit 200 forms image data by imaging the complex amplitude profile or the reflection intensity profile of each A-line.

[0087] (Processing system) The processing system (control system) of the ophthalmologic apparatus 1500b is configured with an arithmetic control unit 200 as its central component.

[0088] (Arithmetic and control unit 200) The arithmetic and control unit 200 forms an OCT image of the fundus oculi Ef from the detection signal input from the DAQ 130. The arithmetic processing for this purpose is the same as that of a conventional swept source type OCT device.

[0089] The arithmetic and control unit 200 controls each part of the fundus camera unit 2, the display device 3, and the OCT unit 100. Hereinafter, it is assumed that the function of the display device 3 is realized by a user interface having a display unit and an operation unit.

[0090] 6 is a functional block diagram showing an example of the configuration of a processing system of the ophthalmic apparatus 1500b, in which some of the components included in the ophthalmic apparatus 1500b are omitted.

[0091] The arithmetic and control unit 200 includes a control unit 210, an image forming unit 220, and a data processing unit 230. The functions of the arithmetic and control unit 200 are realized by one or more processors. In some embodiments, the functions of the arithmetic and control unit 200 are realized by a control processor that realizes the functions of the control unit 210, an image forming processor that realizes the functions of the image forming unit 220, and a data processing processor that realizes the functions of the data processing unit 230.

[0092] (control unit 210) The control unit 210 executes various controls and includes a main control unit 211 and a storage unit 212.

[0093] (Main control unit 211) The main control unit 211 includes a processor and controls each unit of the ophthalmologic apparatus 1500b.

[0094] To control the fundus camera unit 2, the main control unit 211 controls the operation of the observation light source 11, the imaging light source 15, the CCD image sensors 35, 38, and the LEDs 51, 61, the operation of the LCD 39, the movement of the imaging focusing lens 31, the movement of the OCT focusing lens 43, the movement of the reflecting rod 67, the alignment optical system 50, the movement of the focus optical system 60, the movement of the optical path length changing unit 41, and the operation of the optical scanner 42.

[0095] To control the OCT unit 100, the main control unit 211 controls the operation of the light source unit 101, the movement of the optical path length changing unit 114, the operation of the attenuator 120, the operation of the polarization controllers 103 and 118, the operation of the detector 125, and the operation of the DAQ 130.

[0096] As control of the user interface 240, the main controller 211 causes the display unit 240A to display an observed image of the subject's eye E, a photographed image of the subject's eye E, an OCT image of the subject's eye E acquired using the OCT unit 100, measurement results, a GUI, etc. In addition, the main controller 211 receives an operation signal corresponding to the operation content of the operation unit 240B by the user, and controls each unit of the ophthalmologic apparatus 1500b based on the received operation signal.

[0097] In addition, the main control unit 211 can control a moving mechanism 150 that moves the entire optical system relative to the eye E to be examined.

[0098] For example, the main control unit 211 displays a fixation target at a position on the screen of the LCD 39 that corresponds to a manually or automatically set fixation position. The main control unit 211 can also change (continuously or stepwise) the display position of the fixation target displayed on the LCD 39. This makes it possible to move the fixation target (i.e., change the fixation position). The display position and movement manner of the fixation target are set manually or automatically. Manual setting is performed using, for example, a GUI. Automatic setting is performed by, for example, the data processing unit 230.

[0099] The focusing driver 31A moves the photographing focusing lens 31 in the optical axis direction of the photographing optical system 30, and moves the focus optical system 60 in the optical axis direction of the illumination optical system 10. This changes the focus position of the photographing optical system 30. The focusing driver 31A may have separate mechanisms for moving the photographing focusing lens 31 and for moving the focus optical system 60. The focusing driver 31A is controlled when performing focus adjustment, etc.

[0100] The focusing driver 43A moves the OCT focusing lens 43 in the optical axis direction of the measurement light path, thereby changing the focusing position of the measurement light LS. For example, by moving the OCT focusing lens 43 to a first lens position, the focusing position of the measurement light LS can be positioned at or near the fundus Ef. For example, by moving the OCT focusing lens 43 to a second lens position, the focusing position of the measurement light LS can be positioned at the far point position, and the measurement light LS can be made into a parallel beam. The focusing position of the measurement light LS corresponds to the depth position (z position) of the beam waist of the measurement light LS.

[0101] The movement mechanism 150, for example, moves at least the fundus camera unit 2 (optical system) three-dimensionally. In a typical example, the movement mechanism 150 includes at least a mechanism for moving the fundus camera unit 2 in the x direction (left-right direction), a mechanism for moving it in the y direction (up-down direction), and a mechanism for moving it in the z direction (depth direction, front-back direction). The mechanism for movement in the x direction includes, for example, an x-stage that can move in the x direction and an x-movement mechanism that moves the x-stage. The mechanism for movement in the y direction includes, for example, a y-stage that can move in the y direction and a y-movement mechanism that moves the y-stage. The mechanism for movement in the z direction includes, for example, a z-stage that can move in the z direction and a z-movement mechanism that moves the z-stage. Each movement mechanism includes an actuator such as a pulse motor, and operates under the control of the main controller 211.

[0102] Control of the moving mechanism 150 is used for alignment and tracking. Tracking is the act of moving the device optical system in accordance with the eye movement of the subject's eye E. When tracking is performed, alignment and focus adjustment are performed beforehand. Tracking is a function of maintaining a suitable positional relationship where alignment and focus are achieved by making the position of the device optical system follow the eye movement. In some embodiments, the moving mechanism 150 is configured to be controlled to change the optical path length of the reference light (and therefore the optical path length difference between the optical path of the measurement light and the optical path of the reference light).

[0103] In the case of manual alignment, the user operates a user interface 240 described below to move the optical system and the eye E relative to each other so that the displacement of the eye E relative to the optical system is canceled. For example, the main controller 211 controls the movement mechanism 150 by outputting a control signal corresponding to the operation content of the user interface 240 to the movement mechanism 150, thereby moving the optical system and the eye E relative to each other.

[0104] In the case of auto-alignment, the main controller 211 controls the moving mechanism 150 to move the optical system relative to the subject's eye E so that displacement of the subject's eye E relative to the optical system is canceled. In some embodiments, the main controller 211 controls the moving mechanism 150 to move the optical system relative to the subject's eye E by outputting a control signal to the moving mechanism 150 so that the optical axis of the optical system approximately coincides with the axis of the subject's eye E and the distance of the optical system from the subject's eye E is a predetermined working distance. Here, the working distance is a predetermined value also called the working distance of the objective lens 22, and corresponds to the distance between the subject's eye E and the optical system during measurement (photography) using the optical system.

[0105] The main controller 211 controls fundus photography and anterior segment photography by controlling the fundus camera unit 2 etc. The main controller 211 also controls OCT measurement by controlling the fundus camera unit 2 and the OCT unit 100 etc.

[0106] The arithmetic and control unit 200 includes, for example, a processor, RAM, ROM, a hard disk drive, a communication interface, and the like, similar to a conventional computer. A computer program for controlling the ophthalmic apparatus 1500b is stored in a storage device such as a hard disk drive. The arithmetic and control unit 200 may also include various circuit boards, for example, a circuit board for forming OCT images. The arithmetic and control unit 200 may also include operation devices (input devices) such as a keyboard and a mouse, and a display device such as an LCD.

[0107] The fundus camera unit 2, the user interface 240, the OCT unit 100, and the arithmetic and control unit 200 may be configured integrally (i.e., within a single housing) or may be configured separately in two or more housings.

[0108] (Storage unit 212) The storage unit 212 stores various types of data. Examples of data stored in the storage unit 212 include image data of OCT images, image data of fundus images, image data of anterior segment images, and information about the subject's eye. The information about the subject's eye includes information about the subject, such as a patient ID and name, and information about the subject's eye, such as identification information for the left eye or right eye.

[0109] The storage unit 212 also stores various programs and data for operating the ophthalmologic apparatus 1500b.

[0110] The ophthalmologic apparatus 1500b is provided with a user interface 240 for receiving operations from a user and presenting information to the user. The control unit 210 controls the user interface 240 to manage interface processing with the user.

[0111] (User Interface 240) The user interface 240 includes a display unit 240A and an operation unit 240B. The display unit 240A includes a display device of the arithmetic and control unit 200 and the display device 3. The operation unit 240B includes the operation device of the arithmetic and control unit 200 described above. The operation unit 240B may include various buttons and keys provided on the housing of the ophthalmologic apparatus 1500b or on the outside. For example, if the fundus camera unit 2 has a housing similar to that of a conventional fundus camera, the operation unit 240B may include a joystick, an operation panel, etc. provided on this housing. Furthermore, the display unit 240A may include various display devices such as a touch panel provided on the housing of the fundus camera unit 2.

[0112] It should be noted that the display unit 240A and the operation unit 240B do not need to be configured as separate devices. For example, it is possible to use a device in which the display function and the operation function are integrated, such as a touch panel. In this case, the operation unit 240B is configured to include this touch panel and a computer program. The operation content on the operation unit 240B is input to the control unit 210 as an electrical signal. Furthermore, operations and information input may be performed using a graphical user interface (GUI) displayed on the display unit 240A and the operation unit 240B.

[0113] (Image forming unit 220) The image forming unit 220 forms an OCT image (image data) of the subject's eye E based on sampled data obtained by sampling the detection signal from the detector 125 with the DAQ 130. This processing includes processes such as noise removal (noise reduction), filtering, dispersion compensation, and FFT (Fast Fourier Transform), as with conventional swept-source type OCT. In the case of other types of OCT devices, the image forming unit 220 performs known processing depending on the type.

[0114] The image forming unit 220 is configured to include, for example, the aforementioned processor, RAM, ROM, hard disk drive, circuit board, etc. A computer program that causes the processor to execute the above functions is pre-stored in a storage device such as a hard disk drive. Note that in this specification, "image data" and the "image" based on it may be considered to be the same thing.

[0115] (Data processing unit 230) The data processing unit 230 processes data acquired by photographing the subject's eye E and by OCT measurement.

[0116] The data processing unit 230 performs various image processing and analysis processes on the image formed by the image forming unit 220. For example, the data processing unit 230 executes various correction processes such as brightness correction of the image. The data processing unit 230 also performs various image processing and analysis processes on the images (fundus image, anterior eye image, etc.) obtained by the fundus camera unit 2.

[0117] For example, the data processing unit 230 performs known image processing such as interpolation processing to interpolate pixels between tomographic images to form image data of a three-dimensional image of the fundus oculi Ef. Note that image data of a three-dimensional image means image data in which pixel positions are defined by a three-dimensional coordinate system. Image data of a three-dimensional image includes image data consisting of three-dimensionally arranged voxels. This image data is called volume data or voxel data. When displaying an image based on the volume data, the data processing unit 230 performs rendering processing (volume rendering, MIP (Maximum Intensity Projection), etc.) on the volume data to form image data of a pseudo three-dimensional image as viewed from a specific line of sight. This pseudo three-dimensional image is displayed on the user interface 240 (display unit 240A).

[0118] It is also possible to form stack data of multiple tomographic images as image data of a three-dimensional image. Stack data is image data obtained by arranging multiple tomographic images obtained along multiple scan lines in a three-dimensional manner based on the positional relationship of the scan lines. In other words, stack data is image data obtained by expressing multiple tomographic images that were originally defined using separate two-dimensional coordinate systems using a single three-dimensional coordinate system (i.e., embedding them in a single three-dimensional space).

[0119] The data processing unit 230 can perform various rendering operations on the acquired three-dimensional data set (volume data, stack data, etc.) to generate B-mode images (longitudinal and axial cross-sectional images) at any cross-section, C-mode images (transverse and horizontal cross-sectional images) at any cross-section, projection images, shadowgrams, and the like. Images of any cross-section, such as B-mode images and C-mode images, are generated by selecting pixels (voxels) on a specified cross-section from the three-dimensional data set. Projection images are generated by projecting the three-dimensional data set in a predetermined direction (z direction, depth direction, axial direction). Shadowgrams are generated by projecting a portion of the three-dimensional data set (e.g., partial data corresponding to a specific layer) in a predetermined direction. Images viewed from the front side of the subject's eye, such as C-mode images, projection images, and shadowgrams, are called en-face images.

[0120] The data processing unit 230 can construct a B-mode image or a front image (a vessel-enhanced image, angiogram) in which retinal blood vessels and choroidal blood vessels are emphasized based on data collected in time series by OCT (for example, B-scan image data). For example, time-series OCT data can be collected by repeatedly scanning approximately the same region of the subject's eye E.

[0121] In some embodiments, the data processor 230 compares time-series B-scan images obtained by B-scanning approximately the same region and converts pixel values ​​of portions of signal intensity change into pixel values ​​corresponding to the change to construct an enhanced image in which the changed portion is emphasized. Furthermore, the data processor 230 extracts information of a predetermined thickness of a desired region from the constructed multiple enhanced images and constructs the image as an en-face image, thereby forming an OCTA image.

[0122] Images generated by the data processing unit 230 (for example, a three-dimensional image, a B-mode image, a C-mode image, a projection image, a shadowgram, and an OCTA image) are also included in the OCT image.

[0123] Furthermore, the data processing unit 230 performs predetermined analytical processing on the detection results of the interference light obtained by the OCT measurement or on the OCT image formed based on the detection results. The predetermined analytical processing includes identifying predetermined regions (tissues, lesions) in the subject's eye E; calculating the distance (interlayer distance), area, angle, ratio, and density between specified regions; performing calculations using specified formulas; identifying the shape of the predetermined regions; calculating statistical values ​​of these; calculating the distribution of measurement values ​​and statistical values; and image processing based on the results of these analytical processing. Predetermined tissues include blood vessels, the optic disc, the fovea, the macula, etc. Predetermined lesions include exudates, hemorrhage, etc.

[0124] In addition, the data processing unit 230 can perform phase stabilization processing on the OCT data (e.g., three-dimensional complex OCT data, complex OCT volume data) of the test eye E obtained by OCT measurement so as to reduce the effects of phase drift caused by movement of the test eye or phase instability of the OCT optical system 8.

[0125] For example, the image forming unit 220 or the data processing unit 230 forms an OCT image based on the absolute value of the complex OCT data that has been subjected to phase stabilization processing. Since imaging can be performed using the imaginary part of the complex OCT data in addition to the real part, it is possible to obtain an OCT image with even higher resolution.

[0126] For example, the data processing unit 230 forms a phase image (phase information) or an OCTA image based on the absolute value of the complex OCT data that has been subjected to phase stabilization processing. Since components affected by phase drift have been removed from the imaginary part of the complex OCT data, it is possible to acquire a phase image or an OCTA image with even higher accuracy.

[0127] Furthermore, the data processing unit 230 can perform aberration correction processing on the OCT data that has been subjected to the phase stabilization processing, to correct aberrations caused by the subject's eye E or the optical system.

[0128] FIG. 7 is a diagram illustrating the operation of the aberration correction process executed by the data processing unit 230.

[0129] First, the data processing unit 230 searches for parameters of the CAO filter CF as filter information from the complex OCT data DT1 of the subject's eye E obtained by OCT measurement. Hereinafter, "searching for parameters of the CAO filter" as filter information may be expressed as "searching for the CAO filter."

[0130] Next, the data processor 230 performs an aberration correction process PC on the complex OCT data DT1 using the found CAO filter CF to obtain aberration-corrected complex OCT data DT2. In some embodiments, the aberration correction process PC is performed in the frequency domain. In some embodiments, the aberration correction process PC is performed in the spatial domain.

[0131] This makes it possible to improve the accuracy of OCT measurement results without being affected by aberrations caused by the subject's eye E or the optical system. This means improving the accuracy of the real and imaginary parts of the aberration-corrected complex OCT data, enabling higher image quality OCT images (including OCTA images) and improved phase accuracy between images.

[0132] FIG. 8 is an explanatory diagram of a CAO filter according to an embodiment.

[0133] The CAO filter can be expressed by a Zernike polynomial corresponding to the distribution of wavefront aberration on the pupil plane of the subject's eye E. The filter characteristics of the CAO filter can be adjusted by adjusting the coefficients (parameters) of the terms of each degree of the Zernike polynomial.

[0134] The filter characteristics of the CAO filter are determined by combining one or more filters corresponding to a predetermined distribution of wavefront aberrations according to coefficients corresponding to each filter. In this embodiment, as shown in FIG. 8, the CAO filter CF is de and the astigmatism term F in the HV direction (0-90 degrees direction). asHV and the astigmatism term F in the diagonal direction (±45 degrees). asDGThe CAO filter CF is expressed as a polynomial including the coefficients C de , C as_HV , C as_DG The desired filter characteristics can be achieved by adjusting the parameters. The CAO filter CF may include higher-order terms such as a coma aberration term and a spherical aberration term.

[0135] FIG. 9 is a diagram illustrating an example of a search process of the CAO filter according to the embodiment.

[0136] The data processing unit 230 sequentially applies two or more CAO filters having different filter characteristics to the complex OCT data DT1 of the subject's eye E to acquire two or more pieces of aberration-corrected complex OCT data DT11, DT12, ..., DT1M (M is an integer equal to or greater than 2). The data processing unit 230 evaluates the quality of each of the acquired two or more pieces of complex OCT data DT11 to DT1M, and identifies the CAO filter applied to the complex OCT data with the highest quality as the CAO filter of the search result.

[0137] An example of a method for evaluating the quality of complex OCT data is a method for evaluating the image quality of an OCT image formed based on the complex OCT data. Examples of OCT images include a tomographic image, a front image (projection image, en-face image), and an OCTA image. For example, the data processing unit 230 can identify the highest quality complex OCT data based on an image quality evaluation value that indicates the level of image quality of the formed OCT image.

[0138] In some embodiments, the data processing unit 230 can generate parameters (coefficients) of the CAO filter from refractive power information that indicates the refractive power of the subject's eye E. This makes it possible to simplify or omit the search process for the CAO filter (filter information).

[0139] Each unit of the data processing unit 230 that realizes such functions will be described below.

[0140] FIG. 10 is a block diagram showing an example of the configuration of the data processing unit 230 shown in FIG.

[0141] The data processing unit 230 includes a phase stabilization unit 231 , a filter information generation unit 232 , a filter information search unit 300 , an aberration correction unit 234 , and a projection image formation unit 235 .

[0142] (Phase stabilization section 231) The phase stabilization unit 231 performs a phase stabilization process on the complex OCT data of the subject's eye E so as to cancel the influence of phase drift caused by the movement of the subject's eye E, which is the measurement target, or phase instability within the system (OCT optical system 8).

[0143] FIG. 11 shows a block diagram of an example of the configuration of the phase stabilization unit 231 of FIG.

[0144] The phase stabilization unit 231 includes a phase difference profile generation unit 231A, a phase drift extraction unit 231B, a phase difference data removal unit 231C, and a phase correction unit 231D.

[0145] (Phase difference profile generation unit 231A) The phase difference profile generating unit 231A generates a phase difference profile in which phase data representing phase differences averaged for each A line from the three-dimensional complex OCT data is arranged in the B line direction. Specifically, the phase difference profile generating unit 231A calculates the phase difference for each depth position of the A line between two adjacent B frames of the complex OCT data, averages the calculated phase differences in the depth direction (z direction), and arranges the phase differences obtained by averaging in the B line direction to generate a phase difference profile.

[0146] Fig. 12A is a diagram illustrating the operation of the phase difference profile generating unit 231A. Fig. 12A is a diagram schematically illustrating complex OCT data ODT, with the horizontal direction being the x direction and the vertical direction being the y direction.

[0147] For example, the phase difference profile generating unit 231A calculates the phase difference between two adjacent B frames B as shown in Equation (1). k, B k+1 The phase difference profile generating unit 231A accumulates the phase differences calculated for each depth position of the A line between the two B frames B in the z direction, and averages the accumulated phase differences to obtain the phase difference for each A line. k+1 , B k+2 Similarly, the phase difference is calculated for each A line between the two B frames. This process is repeated sequentially to sequentially calculate the phase difference profile between the two B frames for the three-dimensional complex OCT data ODT.

[0148]

number

[0149] (Phase drift extraction unit 231B) The phase drift extraction unit 231B extracts the phase drift from the phase difference profile generated by the phase difference profile generation unit 231 A. Specifically, the phase drift extraction unit 231B extracts the phase drift by performing at least one of smoothing processing, polynomial fitting, and high frequency cut filter processing on the phase difference profile.

[0150] 12B is a diagram illustrating the operation of the phase drift extraction unit 231B. In FIG. 12B, the horizontal axis represents the A line number corresponding to the position of the A line (the incident position of the measurement light scanned in the B scan direction), and the vertical axis represents the phase difference.

[0151] For example, the phase drift extraction unit 231B extracts the phase drift DF0 by performing a smoothing process on the phase difference profile RD0 generated by the phase difference profile generation unit 231A.

[0152] At least one parameter of the smoothing process, polynomial fitting, and high frequency cut filter process performed by the phase drift extraction unit 231B is set based on at least one of the frequency of the phase change of the OCT optical system 8 that acquires the complex OCT data ODT, the speed of the phase change, and the time required for OCT scanning in the OCT optical system 8.

[0153] (Phase difference data removal unit 231C) Before extracting the phase drift, the phase difference data removal unit 231C removes unreliable phase difference data from the phase difference profile generated by the phase difference profile generation unit 231A. The phase drift extraction unit 231B extracts the phase drift from the phase difference profile from which the unreliable phase difference data has been removed by the phase difference data removal unit 231C. This allows for the phase drift to be obtained from which local phase difference changes have been removed.

[0154] Fig. 13 is a diagram illustrating the operation of the phase difference data removal unit 231C. In Fig. 13, similar to Fig. 12B, the horizontal axis represents the A line number corresponding to the position of the A line, and the vertical axis represents the phase difference.

[0155] For example, the phase difference data removal unit 231C removes (thins out) unreliable phase difference data N1 to N4 from the phase difference profile RD0 shown in Fig. 12B to generate the phase difference profile RD1 shown in Fig. 13. The phase drift extraction unit 231B extracts the phase drift DF1 from the phase difference profile RD1 shown in Fig. 13. This makes it possible to suppress the influence of local phase changes (local errors) compared to the phase drift DF0.

[0156] Phase difference data with low reliability includes phase difference data with weak signal strength and phase difference data in which the contribution of phase difference data at a specific depth position is large in the phase difference calculation process (averaging process) of Equation (1). Phase difference data with weak signal strength may reduce the high reliability of phase difference data with strong signal strength. Phase difference data with a large contribution in the phase difference calculation process of Equation (1) is likely to violate the premise that the expected value of the phase difference is zero.

[0157] For example, the phase difference data removing unit 231C identifies the phase difference data that satisfies the formula (2) as data whose signal intensity is less than a predetermined threshold level, and removes the identified data from the phase difference profile.

[0158]

number

[0159] For example, the phase difference data removal unit 231C identifies phase difference data that satisfies equation (3) as data in which the contribution of the phase difference at a predetermined depth position exceeds a predetermined threshold in the averaging process when calculating the phase difference of equation (1), and removes the identified data from the phase difference profile.

[0160]

number

[0161] The phase difference data removal unit 231C is capable of removing at least one of data whose signal strength is below a predetermined threshold level and data whose contribution due to the phase difference at a predetermined depth position in the averaging process exceeds a predetermined threshold as low-reliability data from the phase difference profile.

[0162] (Phase correction section 231D) The phase corrector 231D corrects the phase of the complex OCT data of one of the two B frames for which the phase difference profile has been generated, based on the phase drift extracted by the phase drift extractor 231B.

[0163] For example, the B frame B shown in FIG. k , B k+1 When performing phase correction between the A lines, the phase correction unit 231D calculates the phase difference φ in the phase drift for each A line in the B frame B in the frequency domain. k+1 The complex OCT data in the spatial domain is multiplied by exp(-iφ). In some embodiments, the phase corrector 231D performs a convolution operation using the phase difference φ on the complex OCT data in the spatial domain.

[0164] For example, the phase stabilization unit 231 sequentially performs the above-described phase correction process on B frames of the three-dimensional complex OCT data. That is, for adjacent first and second B frames, the phase stabilization unit 231 corrects the phase of the complex OCT data of the second B frame based on the phase difference profile generated by the phase difference profile generation unit 231A, and then, for the second B frame and a third B frame adjacent to the second B frame, corrects the phase of the complex OCT data of the third B frame based on the phase difference profile generated by the phase difference profile generation unit 231A.

[0165] (Filter information generation unit 232) 10 generates, as filter information, parameters of a CAO filter to be applied to complex OCT data of the subject's eye E. In the example shown in Fig. 8, the parameters of the CAO filter are coefficients of each term of the Zernike polynomial.

[0166] The filter information generation unit 232 generates, as filter information, parameters of a CAO filter that are to be initial values ​​for the search process. For example, the filter information generation unit 232 acquires the filter information by referring to the initial values ​​of the parameters of the CAO filter that are stored in advance in the storage unit 212.

[0167] In some embodiments, the filter information generating unit 232 generates, as filter information, parameters of the CAO filter from refractive power information of the subject's eye E obtained by refractive power measurement of the subject's eye E performed in an external ophthalmic device. That is, the filter information generating unit 232 can generate filter information as reference filter information based on the refractive power information of the subject's eye E. The parameters of the CAO filter are searched for based on the generated reference filter information so that the quality of the complex OCT data reaches a predetermined level.

[0168] The spherical equivalent power SE, spherical power S, cylindrical power C, and cylindrical axis angle A can be calculated from equations (4) to (7) using the coefficients of each term of the Zernike polynomial.

[0169]

number

[0170] In equation (4), S move represents the spherical power of the fixation movement, r represents the pupil diameter, and c2 0 is the coefficient of the defocus term (coefficient C in Figure 8) de In addition, in equations (6) and (7), c2 -2 is the coefficient of the astigmatism term in the DG direction (coefficient C in Figure 8) as_DG (equivalent to c2) 2 is the coefficient of the astigmatism term in the HV direction (coefficient C in Figure 8) as_HV (equivalent to)

[0171] When the coefficients are RMS (Root Mean Square) values, the spherical equivalent power SE, the spherical power S, the cylindrical power C, and the cylindrical axis angle A can be calculated by the formulas (8) to (11).

[0172]

number

[0173] According to equations (4) to (7) or equations (8) to (11), the filter information generation unit 232 can generate the parameters of the CAO filter as filter information by calculating the coefficients of each term of the Zernike polynomial from the refractive power information of the subject's eye E.

[0174] (Filter information search unit 300) The filter information searching unit 300 searches for filter information for correcting aberrations in the complex OCT data so that the quality of the complex OCT data of the subject's eye E reaches a predetermined level. Specifically, the filter information searching unit 300 repeatedly evaluates the quality of the complex OCT data corrected based on the filter information and updates the filter information so that the quality of the complex OCT data reaches a predetermined level. Furthermore, the filter information searching unit 300 can roughly search for filter information by repeatedly evaluating the quality and updating the filter information, and can finely search for filter information by repeatedly updating the filter information and evaluating the quality within the searched search range.

[0175] FIG. 14 shows a block diagram of an example of the configuration of filter information search unit 300 shown in FIG.

[0176] The filter information search unit 300 includes a coarse search unit 310 and a fine search unit 320 .

[0177] (Rough search section 310) The coarse search unit 310 roughly searches for filter information by repeatedly evaluating the quality of the complex OCT data and updating the filter information. The coarse search unit 310 includes a filter test unit 311 and a filter information update unit 312.

[0178] (Filter test unit 311) The filter test unit 311 applies a CAO filter to the complex OCT data and evaluates the quality of the aberration-corrected complex OCT data. The filter test unit 311 includes a filter processing unit 311A ​​and an image quality evaluation unit 311B.

[0179] (Filter processing unit 311A) The filter processing unit 311A ​​performs filtering on the complex OCT data using a known method, using the CAO filter during the coarse search process. For example, the filter processing unit 311A ​​multiplies the complex OCT data in the frequency domain by exp(-iφ) corresponding to the parameters of the CAO filter. For example, the filter processing unit 311A ​​performs convolution on the complex OCT data in the spatial domain using filter coefficients corresponding to the parameters of the CAO filter.

[0180] (Image quality evaluation unit 311B) The image quality evaluation unit 311B evaluates the image quality of an OCT image (fundus image) formed based on the complex OCT data whose aberrations have been corrected by the filtering unit 311 A. For example, the OCT image is formed by the image forming unit 220.

[0181] The image quality evaluation unit 311B is capable of calculating an image quality evaluation value of the OCT image. The image quality evaluation value is a numerical value that indicates the degree of image quality of the OCT image, and is used to evaluate whether the image quality is good or not.

[0182] The image quality evaluation value may be any type of value that can be calculated by any method. A typical image quality evaluation value is expressed as the signal-to-noise ratio (S / N ratio) for two types of image regions in an OCT image. A specific example of the image quality evaluation value is the S / N ratio for the signal in the image region representing the eye region and the noise in the image region representing the background that is not the eye region. The image region representing the eye region is called the signal region, and the image region representing the background is called the background region.

[0183] The image quality evaluation value expressed as the S / N ratio for the signal region and the background region can be calculated by any method, and a specific example will be described below.

[0184] First, the image quality evaluation unit 311B identifies the pixel with the highest brightness and the pixel with the lowest brightness for each of the multiple A-scan images that make up the OCT image. Next, the image quality evaluation unit 311B creates a brightness histogram based on the brightness values ​​of a predetermined range of pixels (e.g., 40 pixels before and after) that includes the identified pixel with the highest brightness. Similarly, the image quality evaluation unit 311B creates a brightness histogram based on the brightness values ​​of a predetermined range of pixels that includes the identified pixel with the lowest brightness.

[0185] Next, the image quality evaluation unit 311B searches for the maximum position (brightness value) where the frequency value exceeds 0 in the histogram corresponding to the pixel group including the pixel with the lowest brightness. Furthermore, in the histogram corresponding to the pixel group including the pixel with the highest brightness, it calculates the total number of pixels (N) included in the range equal to or less than the brightness value searched above and the total number of pixels (S) included in the 255th brightness value from the top of the searched brightness value. The image quality evaluation unit 311B then evaluates what percentage of the image is considered to be signal (i.e., not noise) using the following formula: 100 × S ÷ (S + N). The image quality evaluation unit 311B applies this series of calculations to each A-scan image to obtain multiple numerical values ​​corresponding to multiple A-scan images. The image quality evaluation unit 311B then calculates the average of these numerical values ​​and uses this as the image quality evaluation value.

[0186] (Filter information update unit 312) The filter information update unit 312 updates the parameters of the CAO filter searched by the coarse search unit 310 by increasing or decreasing the parameters by a predetermined increment or decrement, respectively. The increment or decrement may vary depending on the type of parameter, or may be common to two or more types of parameters. In some embodiments, the filter information update unit 312 updates only one of the CAO filter parameters. In some embodiments, the filter information update unit 312 simultaneously updates two or more of the CAO filter parameters.

[0187] As described above, in the coarse search unit 310, the filter test unit 311 acquires complex OCT data in which aberrations have been corrected by applying a CAO filter using the filter processing unit 311A, for example, in the frequency domain. The filter test unit 311 then evaluates the image quality of an OCT image formed based on the complex OCT data using the image quality evaluation unit 311B in the spatial domain. The coarse search unit 310 roughly searches for a CAO filter by repeatedly updating the CAO filter parameters using the filter information update unit 312 and evaluating the image quality using the filter test unit 311.

[0188] (Detailed search section 320) The fine search unit 320 finely searches for filter information by repeatedly updating the filter information and evaluating the quality within the search range searched by the coarse search unit 310. The fine search unit 320 includes a filter test unit 321, a filter information update unit 322, and a gradient calculation unit 323.

[0189] (Filter test unit 321) The filter test unit 321 applies a CAO filter to the complex OCT data and evaluates the quality of the aberration-corrected complex OCT data, similar to the filter test unit 311. The filter test unit 321 includes a filter processing unit 321A and an image quality evaluation unit 321B.

[0190] (Filter processing unit 321A) The filter processing unit 321A performs filtering on the complex OCT data using a CAO filter during fine search processing using a known method. The processing by the filter processing unit 321A is similar to that of the filter processing unit 311A.

[0191] (Image quality evaluation unit 321B) The image quality evaluation unit 321B evaluates the image quality of an OCT image (fundus image) formed based on the complex OCT data whose aberrations have been corrected by the filter processing unit 321 A. The image quality evaluation unit 321B is capable of calculating an image quality evaluation value of the OCT image, similar to the image quality evaluation unit 311B.

[0192] (Filter information update unit 322) The filter information update unit 322 increases or decreases the parameters of the CAO filter searched by the fine search unit 320 to update the parameters. The filter information update unit 322 can update the parameters of the CAO filter according to a gradient calculated by a gradient calculation unit 323 (described later). In some embodiments, the filter information update unit 322 updates only one of the parameters of the CAO filter. In some embodiments, the filter information update unit 322 simultaneously updates two or more parameters of the CAO filter.

[0193] (Gradient calculation unit 323) The gradient calculation unit 323 calculates the gradient of the image quality evaluation value calculated by the image quality evaluation unit 321B.

[0194] For example, the gradient calculation unit 323 calculates the gradient of the image quality evaluation value that changes as the filter information is updated. The filter information update unit 322 updates the filter information based on the gradient of the image quality evaluation value calculated by the gradient calculation unit 323. Specifically, the filter information update unit 322 updates the filter information so that the increase or decrease becomes smaller the more gradual the gradient of the calculated image quality evaluation value, and so that the increase or decrease becomes larger the more steep the gradient.

[0195] As described above, in the fine search unit 320, the filter test unit 321 acquires complex OCT data in which aberrations have been corrected by applying a CAO filter using the filter processing unit 321A, for example, in the frequency domain. The filter test unit 321 then evaluates the image quality of the OCT image formed based on the complex OCT data using the image quality evaluation unit 321B in the spatial domain. In the fine search unit 320, the gradient calculation unit 323 calculates the gradient of the image quality evaluation value that changes as the filter information is updated, and the filter information update unit 322 updates the filter information based on the calculated gradient of the image quality evaluation value. The fine search unit 320 finely searches for a CAO filter by repeatedly updating the CAO filter parameters using the filter information update unit 322 in accordance with the gradient of the image quality evaluation value and evaluating the image quality using the filter test unit 321.

[0196] (Aberration correction unit 234) The aberration correction unit 234 shown in FIG. 10 corrects aberrations in the complex OCT data of the subject's eye E based on the CAO filter (parameters) searched for by the filter information search unit 300. The aberration correction unit 234 performs filtering on the complex OCT data using the CAO filter by a known method. For example, the aberration correction unit 234 multiplies the complex OCT data in the frequency domain by exp(-iφ') corresponding to the parameters of the CAO filter. For example, the aberration correction unit 234 performs a convolution operation on the complex OCT data in the spatial domain using a filter coefficient corresponding to the parameters of the CAO filter.

[0197] The function of at least one of the filter processing unit 311A ​​and the filter processing unit 321A may be realized by the aberration correction unit 234.

[0198] (Projection image forming unit 235) The projection image forming unit 235 forms a projection image based on the complex OCT data of the subject's eye E. For example, the projection image forming unit 235 forms a projection image based on the complex OCT data whose aberrations have been corrected by the aberration correcting unit 234.

[0199] The projection image forming unit 235 forms a projection image by projecting a three-dimensional image of the subject's eye E in the z direction. For example, the projection image is used to determine whether the quality of the complex OCT data is good or bad.

[0200] In the ophthalmologic apparatus 1500b having the above configuration, the main controller 211 according to the embodiment functions as a display controller and can cause the display unit 240A to display aberration information on the pupil plane of the subject's eye E corresponding to the parameters of the searched CAO filter. The aberration information includes at least one of information representing the refractive power of the subject's eye E, Zernike coefficients, and distribution information of the phase shift of light (wavefront aberration information). The information representing the refractive power includes at least one of spherical equivalent power (SE), spherical power (S), astigmatism power (C), and astigmatic axis angle (A).

[0201] The data processing unit 230 that functions as described above is configured to include, for example, the above-mentioned processor, RAM, ROM, hard disk drive, circuit board, etc. A computer program that causes the processor to execute the above functions is stored in advance in a storage device such as a hard disk drive.

[0202] The ophthalmological information processing device 1200, the ophthalmological information processing units 1200a and 1200b, and the data processing unit 230 are an example of an "ophthalmological information processing device" according to the embodiment. The phase difference profile generating unit 231A is an example of a "generating unit" according to the embodiment. The phase drift extracting unit 231B is an example of an "extracting unit" according to the embodiment. The phase difference data removing unit 231C is an example of a "removing unit" according to the embodiment. The image forming unit 220 or the data processing unit 230 is an example of an "image forming unit" according to the embodiment. The OCT optical system 1101 or the OCT optical system 8 is an example of a "measurement system" according to the embodiment.

[0203] [Operation] The operation of the ophthalmologic apparatus 1500b according to the embodiment will be described.

[0204] 15 to 23 show an example of operation of the ophthalmologic apparatus 1500b according to the embodiment. FIGS. 15 to 17 and 19 to 23 show flowcharts of an example of operation of the ophthalmologic apparatus 1500b according to the embodiment. FIG. 16 shows a flowchart of an example of operation of step S4 in FIG. 15. FIG. 17 shows a flowchart of an example of operation of step S11 in FIG. 16. FIG. 19 shows a flowchart of an example of operation of step S13 in FIG. 16. FIG. 20 shows a flowchart of an example of operation of steps S22 to S24 in FIG. 19. FIG. 21 shows a flowchart of an example of operation of step S31 in FIG. 20. FIG. 22 shows a flowchart of an example of operation of step S25 in FIG. 19. FIG. 23 shows a flowchart of an example of operation of step S54 in FIG. 22. The storage unit 212 stores computer programs for realizing the processes shown in FIGS. 15 to 17 and 19 to 23. The main control unit 211 operates in accordance with this computer program to execute the processes shown in Figures 15 to 17 and Figures 19 to 23. Figure 18 is a diagram illustrating the operations of steps S12 to S15 in Figure 16.

[0205] (S1: Set scan conditions) First, the main control unit 211 accepts the scan conditions specified by the user.

[0206] The user can specify a scan mode and a scan range by operating the operation unit 240 B. When the user specifies a scan mode and a scan range by operating the operation unit 240 B, the main control unit 211 analyzes the operation information from the operation unit 240 B and identifies the specified scan mode and scan range.

[0207] In some embodiments, the main control unit 211 sets at least one of a scan mode and a scan range corresponding to the operation mode, based on the operation mode designated by the user.

[0208] (S2: Alignment) Next, the main control unit 211 performs alignment.

[0209] For example, the main controller 211 controls the alignment optical system 50 to project an alignment index onto the subject's eye E. At this time, a fixation target by the LCD 39 is also projected onto the subject's eye E. The main controller 211 controls the movement mechanism 150 based on the movement amount of the optical system specified based on the received light image acquired by the image sensor 35, for example, to move the optical system by the movement amount relative to the subject's eye E. The main controller 211 repeatedly executes this process. As a result, the optical system is positioned so that the optical axis of the optical system approximately coincides with the axis of the subject's eye E and the distance of the optical system to the subject's eye E is a predetermined working distance.

[0210] (S3: OCT scan) Next, the main controller 211 controls the OCT unit 100 to perform an OCT scan under the scan conditions set in step S1.

[0211] Specifically, the main controller 211 controls the optical scanner 42 to deflect the measurement light LS generated based on the light L0 emitted from the light source unit 101 and scan a predetermined portion of the subject's eye E (e.g., the fundus) with the deflected measurement light LS. The detection result of the interference light obtained by scanning the measurement light LS is sampled in synchronization with the clock KC. Three-dimensional complex OCT data of the subject's eye E is acquired from the detection result of the interference light.

[0212] (S4: Aberration correction) Next, the main controller 211 controls the data processor 230 to execute aberration correction processing on the complex OCT data acquired in step S3. In step S4, as will be described later, a CAO filter (parameters) is searched for, and the CAO filter obtained by the search is applied to the complex OCT data. Details of step S4 will be described later.

[0213] (S5:Display?) Next, the main controller 211 determines whether or not to display the aberration information corresponding to the CAO filter found in step S4 on the display unit 240A. For example, the main controller 211 determines whether or not to display the aberration information on the display unit 240A based on the operation content of the operation unit 240B by the user. For example, the main controller 211 determines whether or not to display the aberration information on the display unit 240A according to a pre-specified operation mode.

[0214] When it is determined in step S5 that the aberration information is to be displayed on the display unit 240A (step S5: Y), the operation of the ophthalmic apparatus 1500b proceeds to step S6. When it is determined in step S5 that the aberration information is not to be displayed on the display unit 240A (step S5: N), the operation of the ophthalmic apparatus 1500b proceeds to step S7.

[0215] (S6: Display aberration information) When it is determined in step S5 that the aberration information is to be displayed on the display unit 240A (step S5: Y), the main controller 211 causes the display unit 240A to display aberration information on the pupil plane of the subject's eye E corresponding to the parameters of the CAO filter found in step S4. The aberration information includes a distribution map of the phase shift of light on the pupil plane of the subject's eye E (phase distribution map). At this time, the main controller 211 may display Zernike coefficients and a tomographic image and a projection image formed based on the complex OCT data to which the found CAO filter has been applied on the same screen as the distribution map.

[0216] (S7: Forming an OCT image) Following step S6, or when it is determined in step S5 that the aberration information should not be displayed on the display unit 240A (step S5: N), the main controller 211 controls the image forming unit 220 or the data processor 230 to form an OCT image based on the complex OCT data to which the CAO filter searched in step S4 has been applied. OCT images include a tomographic image, a projection image, an en-face image, and an OCTA image.

[0217] In some embodiments, the process of step S7 is started based on the operation performed by the user on operation unit 240B.

[0218] This is the end of the operation of the ophthalmologic apparatus 1500b (END).

[0219] The process of step S4 in FIG. 15 is executed as shown in FIG.

[0220] (S11: Phase stabilization) When the complex OCT data of the subject's eye E is acquired in step S4, the main controller 211 controls the phase stabilization part 231 to execute a phase stabilization process on the acquired complex OCT data.

[0221] As described above, the phase stabilization unit 231 performs the phase stabilization process on the three-dimensional complex OCT data of the subject's eye E. Details of step S11 will be described later.

[0222] (S12: Fourier transform) Next, the main controller 211 performs a known Fourier transform process on the three-dimensional complex OCT data that has been subjected to the phase stabilization process in step S11, converting it into OCT data in the frequency domain.

[0223] (S13: Aberration evaluation) Next, the main control unit 211 controls the data processing unit 230 (filter information searching unit 300) to perform an aberration evaluation for searching for a CAO filter.

[0224] The filter information searching unit 300 updates the CAO filter parameters while evaluating the image quality of the OCT image formed based on the complex OCT data to which the CAO filter is applied, thereby identifying the optimal CAO filter parameters. Details of step S13 will be described later.

[0225] (S14: Aberration correction) Next, the main control unit 211 controls the aberration correction unit 234 to apply the CAO filter found in step S13 to the 3D complex OCT data of the subject's eye E acquired in step S3 of FIG. 15, thereby correcting the aberration of the 3D complex OCT data.

[0226] (S15: Inverse Fourier transform) Next, in step S14, the main controller 211 performs a known inverse Fourier transform process on the aberration-corrected three-dimensional complex OCT data to convert it into OCT data in the spatial domain.

[0227] This is the end of the process in step S4 of FIG. 15 (END).

[0228] Step S11 in FIG. 16 is executed as shown in FIG.

[0229] (S11-1: Set reference data) First, the phase stabilization unit 231 sets data of a predetermined B frame formed based on the three-dimensional complex OCT data as reference data. For example, data B1 of the uppermost B frame in the three-dimensional complex OCT data is extracted as the reference data (see FIG. 12A).

[0230] (S11-2: Set target data) Next, the phase stabilization unit 231 sets, as target data, data B2 of a B frame adjacent in the y direction to reference data B1 extracted from data of a predetermined B frame formed based on the three-dimensional complex OCT data.

[0231] (S11-3: Generate phase difference profile) Next, the phase difference profile generation unit 231A calculates the phase difference for each depth position of the A line between the data B1 and B2 of two adjacent B frames. The phase difference profile generation unit 231A averages the calculated phase differences in the z direction to generate a phase difference profile in which the phase differences for each A line are arranged in the B line direction.

[0232] (S11-4: Remove phase difference data) Subsequently, the phase difference data removing unit 231C removes the phase difference data with low reliability from the phase difference profile generated in step S11-3.

[0233] For example, the phase difference data removing unit 231C removes the phase difference data that satisfies the formula (2) or the formula (3) from the phase difference profile generated in step S11-3.

[0234] (S11-5: Extraction of phase drift) Next, the phase drift extraction unit 231B extracts the phase drift by performing at least one of smoothing processing, polynomial fitting, and high frequency cut filter processing on the phase difference profile from which the unreliable phase difference data has been removed in step S11-4.

[0235] (S11-6: Phase correction) Next, the phase corrector 231D corrects the phase of the target data as described above, based on the phase drift extracted in step S11-5.

[0236] (S11-7: End?) Next, the phase stabilization unit 231 (or the main control unit 211) determines whether or not to terminate the phase stabilization process. For example, the phase stabilization unit 231 determines whether or not to terminate the phase stabilization process by determining whether or not the phase stabilization process has been performed on data of all B frames in the 3D complex OCT data.

[0237] When it is determined in step S11-7 that the phase stabilization process is to be ended (step S11-7: Y), the operation of step S11 is ended (END). When it is determined in step S11-7 that the phase stabilization process is not to be ended (step S11-7: N), the operation of step S11 proceeds to step S11-8.

[0238] (S11-8: Set target data to reference data) When it is determined in step S11-7 that the phase stabilization process should not be ended (step S11-7: N), the phase stabilization unit 231 sets the target data as the reference data. After that, the operation of the phase stabilization unit 231 proceeds to step S11-2.

[0239] For example, the phase stabilization unit 231 sets the B frame data B2 as the reference data. As a result, in the next step S11-2, the B frame data B3 adjacent to the B frame data B2 in the y direction is set as the target data, and phase correction is performed between the B frame data B2 and B3. The above phase correction process is sequentially performed on all B frame data in the 3D complex OCT data.

[0240] FIG. 18 is a diagram illustrating the operations of steps S12 to S15 in FIG.

[0241] In step S12, the complex OCT data OD1 that has undergone phase stabilization processing in step S11 is converted into frequency-domain complex OCT data FD1. In steps S13 and S14, the CAO filter CF found in the frequency domain is applied to the complex OCT data FD1 to correct aberrations in the complex OCT data. In step S15, the aberration-corrected complex OCT data is converted into spatial-domain complex OCT data OD2.

[0242] The process of step S13 in FIG. 16 is executed as shown in FIG.

[0243] (S21: Generate filter information) The main control unit 211 controls the filter information generation unit 232 to generate parameters for the CAO filter.

[0244] The filter information generating unit 232 acquires predetermined initial values ​​and generates them as parameters of the CAO filter. When refractive power information of the subject's eye E is acquired from an external ophthalmic device, the filter information generating unit 232 generates parameters of the CAO filter from the refractive power information. When a past CAO filter is to be reused, the filter information generating unit 232 generates parameters of the CAO filter by reading out parameters of the past CAO filter stored in the storage unit 212.

[0245] Subsequently, the main control unit 211 controls the coarse search unit 310 to execute the coarse search process of steps S22 to S24, and then controls the fine search unit 320 to execute the fine search process of step S25.

[0246] (S22: Search for the coefficient of the defocus term) First, the main control unit 211 controls the rough search unit 310 to calculate the coefficient C of the defocus term of the CAO filter in FIG. de The details of step S22 will be described later.

[0247] (S23: Search for the coefficient of the astigmatism term in the HV direction) Next, the main control unit 211 controls the rough search unit 310 to find the coefficient C of the astigmatism term in the HV direction of the CAO filter in FIG. as_HV The process of step S23 is executed in the same manner as step S22.

[0248] (S24: Search for the coefficient of the diagonal astigmatism term) Next, the main control unit 211 controls the coarse search unit 310 to find the coefficient C of the astigmatism term in the diagonal direction of the CAO filter in FIG. as_DG The process of step S24 is executed in the same manner as step S22.

[0249] (S25: Detailed search) Next, the main control unit 211 controls the fine search unit 320 to execute the fine search process for the above coefficients of the CAO filter in Fig. 8. Details of step S25 will be described later.

[0250] This is the end of the process in step S13 in FIG. 16 (END).

[0251] Steps S22 to S24 in Fig. 19 are each executed as shown in Fig. 20. That is, the coefficient C of the defocus term in step S22 de The search process is performed as shown in FIG. 20, and the coefficient C of the astigmatism term in the HV direction in step S23 as_HV The search process is performed as shown in FIG. 20. In addition, the coefficient C of the astigmatism term in the diagonal direction in step S24 as_DG The search process is also performed as shown in FIG.

[0252] (S31: Filter test) The coarse search unit 310 applies the CAO filter, for which coefficients are currently set, to the complex OCT data in the filter test unit 311, and executes a filter test to evaluate the image quality of an OCT image formed based on the complex OCT data to which the CAO filter has been applied. In the filter test, an image quality evaluation value of the formed OCT image is calculated. Details of step S31 will be described later.

[0253] (S32:End?) Next, the coarse search unit 310 (or the main control unit 211) determines whether to terminate the filter test that is being executed while sequentially updating the coefficients. For example, the coarse search unit 310 determines to continue the filter test when the coefficients are within a predetermined search range, and determines to terminate the filter test when the search range is exceeded. For example, the coarse search unit 310 determines to continue the filter test when the predetermined number of updates of the coefficients is equal to or less than a threshold, and determines to terminate the filter test when the number of updates exceeds the threshold.

[0254] When it is determined in step S32 that the filter test is to be ended (step S32: Y), the operation of the rough search unit 310 proceeds to step S34. When it is determined in step S32 that the filter test is not to be ended (step S32: N), the operation of the rough search unit 310 proceeds to step S33.

[0255] (S33: Update coefficients) When it is determined in step S32 that the filter test should not be ended (step S32: N), the filter information update unit 312 increases or decreases the coefficient by a predetermined increment or decrement, respectively. After that, the operation of the coarse search unit 310 proceeds to step S31.

[0256] (S34: Identify the coefficients) When it is determined in step S32 that the filter test is to be ended (step S32: Y), the coarse search unit 310 identifies the coefficients of the CAO filter.

[0257] The coarse search unit 310 identifies the coefficients of the CAO filter applied to the OCT image with the best image quality based on the multiple image quality evaluation values ​​obtained by repeatedly executing the filter test in step S31. For example, the coarse search unit 310 identifies the coefficients of the CAO filter applied to the OCT image with the maximum or minimum image quality evaluation value.

[0258] With the above, steps S22 to S24 in FIG. 19 are completed (end).

[0259] The process of step S31 in FIG. 20 is executed as shown in FIG.

[0260] (S41: Filter processing) The filter test unit 311 applies a CAO filter to the complex OCT data in the filter processing unit 311A.

[0261] (S42: Inverse Fourier transform) Next, the filter test unit 311 (data processing unit 230) performs an inverse Fourier transform on the complex OCT data that has been subjected to the filtering process in step S41, to generate complex OCT data in the spatial domain.

[0262] (S43: Forming a projection image) Next, the projection image forming unit 235 forms a projection image based on the complex OCT data in the spatial domain generated in step S43.

[0263] (S44: Calculate the image quality evaluation value) Next, the image quality evaluation unit 311B calculates an image quality evaluation value of the projection image formed in step S43.

[0264] This is the end of the process in step S31 in FIG. 20 (END).

[0265] The process of step S25 in FIG. 19 is executed as shown in FIG.

[0266] (S51: Filter test) The fine search unit 320 applies a CAO filter to the complex OCT data in the filter test unit 321. Thereafter, the filter test unit 321 executes a filter test to evaluate the image quality of the OCT image formed based on the complex OCT data to which the CAO filter has been applied. Step S51 is executed in the same manner as step S31 (steps S41 to S44) (see FIG. 21). That is, an image quality evaluation value is also calculated in step S51.

[0267] (S52: Save image quality evaluation value) Next, the fine search unit 320 stores the image quality evaluation value calculated in step S51 in a storage unit such as the storage unit 212.

[0268] (S53:End?) Next, the fine search unit 320 (or the main control unit 211) determines whether to terminate the filter test, which is being executed while sequentially updating the coefficients. For example, when the degree of improvement in image quality based on the image quality evaluation value saved in step S52 is equal to or less than a predetermined threshold, the fine search unit 320 determines that further improvement in image quality is difficult and determines to terminate the filter test. When the degree of improvement in image quality exceeds the threshold, the fine search unit 320 determines that further improvement in image quality is possible and determines to continue the filter test. The degree of improvement in image quality corresponds to the gradient of the image quality evaluation value. Also, for example, the fine search unit 320 determines to continue the filter test when the number of updates of the predetermined coefficients is equal to or less than a threshold, and determines to terminate the filter test when the number of updates exceeds the threshold.

[0269] When it is determined in step S53 that the filter test is to be ended (step S53: Y), the operation of the fine search unit 320 proceeds to step S56. When it is determined in step S53 that the filter test is not to be ended (step S53: N), the operation of the fine search unit 320 proceeds to step S54.

[0270] (S54: Analyze the gradient) When it is determined in step S53 that the filter test should not be ended (step S53: N), the fine search unit 320 calculates the gradient when each coefficient of the CAO filter is slightly changed in the gradient calculation unit 323. Details of step S54 will be described later.

[0271] (S55: Update coefficients) Subsequently, the filter information update unit 322 updates the coefficients of the CAO filter by the amount of change according to the gradient calculated in step S54. After that, the operation of the fine search unit 320 proceeds to step S51.

[0272] (S56: Identify the coefficients) When it is determined in step S53 that the filter test is to be ended (step S53: Y), the fine search unit 320 identifies the coefficients of the CAO filter.

[0273] For example, if it is determined in step S53 that the filter test should be terminated when the degree of improvement in image quality is below a predetermined threshold, the fine search unit 320 identifies the coefficients of the CAO filter applied to the OCT image having the image quality evaluation value saved in step S52.

[0274] For example, if it is determined in step S53 that the filter test should be terminated when the predetermined number of coefficient updates exceeds a threshold, the fine search unit 320 identifies the coefficients of the CAO filter applied to the OCT image with the best image quality based on the multiple image quality evaluation values ​​obtained by repeatedly executing the filter test in step S51. For example, the fine search unit 320 identifies the coefficients of the CAO filter applied to the OCT image with the maximum or minimum image quality evaluation value.

[0275] This is the end of the process in step S25 of FIG. 19 (END).

[0276] The process of step S54 in Fig. 22 is executed as shown in Fig. 23. Fig. 23 shows an example of processing for searching the defocus term, the astigmatism term in the HV direction, the astigmatism term in the diagonal direction, and the spherical aberration term of the CAO filter. Note that Fig. 23 shows an example of processing for sequentially searching multiple coefficients of the CAO filter shown in Fig. 8, but the process may also be executed to search multiple coefficients of the CAO filter shown in Fig. 8 in parallel.

[0277] (S61:C de ?) The fine search unit 320 searches for a coefficient C de It is determined whether or not

[0278] The coefficient to be searched is the coefficient C of the defocus term de When it is determined that the coefficient is the coefficient C of the defocus term (step S61: Y), the fine search unit 320 executes the processes of steps S61-1 to S61-5. deIf it is determined that this is not the case (step S61: N), the operation of the fine search section 320 proceeds to step S62.

[0279] (S61-1: Coefficient (C de +δ) In step S61, the coefficient to be searched is the coefficient C of the defocus term. de When it is determined that the coefficient C de "C de Update to "+δ".

[0280] (S61-2: Filter test) Next, the filter test unit 321 applies the CAO filter whose coefficients have been updated in step S61-1 to the complex OCT data, and performs a filter test to evaluate the image quality of the OCT image formed based on the complex OCT data to which the CAO filter has been applied. Step S61-1 is performed in the same manner as step S31 (steps S41 to S44) (see FIG. 21). In step S61-2, an image quality evaluation value is calculated.

[0281] (S61-3: Coefficient (C de -δ) Next, the filter information update unit 322 updates the coefficient C de "C de Update to "-δ".

[0282] (S61-4: Filter test) Next, the filter test unit 321 applies the CAO filter whose coefficients have been updated in step S61-3 to the complex OCT data, and performs a filter test to evaluate the image quality of the OCT image formed based on the complex OCT data to which the CAO filter has been applied. Step S61-3 is performed in the same manner as step S31 (steps S41 to S44) (see FIG. 21). In step S61-3, an image quality evaluation value is calculated.

[0283] (S61-5: Calculate the gradient) Next, the gradient calculation unit 323 calculates the gradient of the image quality evaluation value based on the image quality evaluation value calculated in step S61-2 and the image quality evaluation value calculated in step S61-4. Thereafter, the operation of the fine search unit 320 proceeds to step S61.

[0284] (S62:C as_HV ?) In step S61, the coefficient to be searched is the coefficient C of the defocus term. de If it is determined that the coefficient is not the coefficient C of the astigmatism term in the HV direction (step S61: N), the fine search unit 320 as_HV It is determined whether or not

[0285] In step S62, the coefficient to be searched is the coefficient C of the astigmatism term in the HV direction. as_HV When it is determined that the coefficient is the coefficient C of the astigmatism term (step S62: Y), the fine search unit 320 executes the processes of steps S62-1 to S62-5. as_HV If it is determined that this is not the case (step S62: N), the operation of the fine search section 320 proceeds to step S63.

[0286] (S62-1: Coefficient (C as_HV +δ) In step S62, the coefficient to be searched is the coefficient C of the astigmatism term in the HV direction. as_HV If it is determined that the coefficient C as_HV "C as_HV +δ". "δ" in step S62-1 may be different from "δ" in step S61-1.

[0287] (S62-2: Filter test) Next, similar to step S61-1, the filter test unit 321 applies the CAO filter whose coefficients have been updated in step S62-1 to the complex OCT data, and performs a filter test to evaluate the image quality of the OCT image formed based on the complex OCT data to which the CAO filter has been applied (see FIG. 21).

[0288] (S62-3: Coefficient (C as_HV -δ) Next, the filter information update unit 322 updates the coefficient C as_HV "C as_HV Update to "-δ".

[0289] (S62-4: Filter test) Next, similar to step S61-4, the filter test unit 321 applies the CAO filter whose coefficients have been updated in step S62-3 to the complex OCT data, and performs a filter test to evaluate the image quality of the OCT image formed based on the complex OCT data to which the CAO filter has been applied (see FIG. 21).

[0290] (S62-5: Calculate the gradient) Next, as in step S61-5, gradient calculation section 323 calculates the gradient of the image quality evaluation value based on the image quality evaluation value calculated in step S62-2 and the image quality evaluation value calculated in step S62-4. Thereafter, the operation of fine search section 320 proceeds to step S61.

[0291] (S63:C as_DG ?) In step S62, the coefficient to be searched is the coefficient C of the astigmatism term in the HV direction. as_HV If it is determined that the coefficient is not C (step S62: N), the fine search unit 320 determines that the coefficient to be searched is the coefficient C of the astigmatism term in the diagonal direction. as_DG It is determined whether or not

[0292] In step S63, the coefficient to be searched is the coefficient C of the astigmatism term in the diagonal direction. as_DGWhen it is determined that the coefficient is a diagonal astigmatism term coefficient C as_DG If it is determined that this is not the case (step S63: N), the operation of the fine search section 320 proceeds to step S64.

[0293] (S63-1: Coefficient (C as_DG +δ) (S63-2: Filter test) (S63-3: Coefficient (C as_DG -δ) (S63-4: Filter test) (S63-5: Calculate the gradient) In step S63, the coefficient to be searched is the coefficient C of the astigmatism term in the diagonal direction. as_DG If it is determined that the coefficient C of the astigmatism term in the diagonal direction is as_DG The gradient of the image quality evaluation value is calculated for (steps S63-1 to S63-5). After that, the operation of fine search section 320 proceeds to step S61. Steps S63-1 to S63-5 are the same as steps S61-1 to S61-5, and therefore detailed description will be omitted.

[0294] (S64:C sph ?) In step S63, the coefficient to be searched is the coefficient C of the astigmatism term in the diagonal direction. as_DG If it is determined that the coefficient is not the coefficient C of the spherical aberration term (step S63: N), the fine search unit 320 sph It is determined whether or not

[0295] In step S64, the coefficient to be searched is the coefficient C of the spherical aberration term. sph If it is determined that this is the case (step S64: Y), the fine search section 320 executes the processes of steps S64-1 to S64-5.

[0296] (S64-1: Coefficient (C sph +δ) (S64-2: Filter test) (S64-3: Coefficient (C sph -δ) (S64-4: Filter test) (S64-5: Calculate the gradient) In step S64, the coefficient to be searched is the coefficient C of the spherical aberration term. sph If it is determined that the coefficient C of the spherical aberration term is sph The gradient of the image quality evaluation value is calculated for (steps S64-1 to S64-5). Thereafter, the operation of fine search section 320 proceeds to step S61. Steps S64-1 to S64-5 are the same as steps S61-1 to S61-5, and therefore detailed description thereof will be omitted.

[0297] In step S64, the coefficient to be searched is the coefficient C of the spherical aberration term. sph If it is determined that this is not the case (step S64: N), the operation of the fine search unit 320 executes the same process for the coefficient of the next term. Note that when the coefficients of all terms have been processed, the process of step S54 in FIG. 22 ends.

[0298] [Variations] In the above embodiment, the parameters (filter information) of the CAO filter according to the embodiment may be searched for for each OCT measurement region (for each angle of view) in the subject's eye E. In this case, the display unit 240A may display aberration information on the pupil plane of the subject's eye E corresponding to the parameters of the CAO filter searched for for each OCT measurement region in the subject's eye E.

[0299] In some embodiments, a program for causing a computer to execute the above-described ophthalmologic information processing method is provided. Such a program can be stored in any non-transitory computer-readable recording medium. Examples of such a recording medium include semiconductor memory, optical disks, magneto-optical disks (CD-ROMs, DVD-RAMs, DVD-ROMs, MOs, etc.), and magnetic storage media (hard disks, floppy disks, ZIPs, etc.). The program can also be transmitted and received via a network such as the Internet or a LAN.

[0300] [Effect] An ophthalmological information processing apparatus, an ophthalmological apparatus, an ophthalmological information processing method, and a program according to an embodiment will be described.

[0301] The ophthalmological information processing apparatus (ophthalmological information processing apparatus 1200, ophthalmological information processing units 1200a and 1200b, data processing unit 230) according to the embodiment includes a generation unit (phase difference profile generation unit 231A), an extraction unit (phase drift extraction unit 231B), and a phase correction unit (231D). The generation unit generates a phase difference profile by averaging the phase differences calculated for each depth position of the A line between two adjacent B frames of complex OCT data of the subject's eye (E) in the depth direction. The extraction unit extracts a phase drift from the phase difference profile generated by the generation unit. The phase correction unit corrects the phase of the first complex OCT data of one of the two B frames based on the phase drift extracted by the extraction unit.

[0302] According to this aspect, OCT data that is not affected by phase changes due to movement of the subject's eye or phase instability within the OCT measurement system can be acquired through simple processing, thereby improving the accuracy of phase information obtained from the OCT data.

[0303] Some embodiments include a removal unit (phase difference data removal unit 231C) that removes unreliable phase difference data from the phase difference profile. The extraction unit extracts a phase drift in which local phase difference changes have been removed from the phase difference profile from which the unreliable phase difference data has been removed by the removal unit.

[0304] According to this embodiment, it is possible to acquire OCT data that is robust against local phase noise.

[0305] In some embodiments, the unreliable phase difference data includes at least one of data in which the signal strength is below a predetermined threshold level and data in which the contribution from the phase difference at a predetermined depth position in the averaging process exceeds a predetermined threshold.

[0306] According to this embodiment, OCT data that is robust to local phase noise can be acquired through simple processing.

[0307] In some embodiments, the extractor extracts the phase drift by performing at least one of smoothing, polynomial fitting, and high-frequency cut filtering on the phase difference profile.

[0308] According to this aspect, OCT data that is not affected by phase changes due to movement of the subject's eye or phase instability within the OCT measurement system can be acquired through even simpler processing.

[0309] In some embodiments, at least one parameter of the smoothing process, the polynomial fitting, and the high-frequency cut filter process is set based on at least one of the frequency of the phase change of the measurement system that acquires the complex OCT data, the speed of the phase change, and the time required for the OCT scan in the measurement system.

[0310] According to this embodiment, it is possible to extract the phase drift under optimal conditions corresponding to the environment in which the complex OCT data is acquired.

[0311] In some embodiments, for adjacent first and second B frames, the phase of the complex OCT data of the second B frame is corrected based on the phase difference profile generated by the generator, and then for the second B frame and a third B frame adjacent to the second B frame, the phase of the complex OCT data of the third B frame is corrected based on the phase difference profile generated by the generator.

[0312] According to this aspect, it is possible to stabilize the phase of three-dimensional complex OCT data with simple processing.

[0313] Some embodiments include an image forming unit (image forming unit 220, data processing unit 230) that forms an OCT image of the test eye based on complex OCT data of the test eye in which the complex OCT data of at least one B frame has been corrected by a phase correction unit.

[0314] According to this aspect, it is possible to form an OCT image that is robust against phase changes caused by movement of the subject's eye or phase instability within the OCT measurement system.

[0315] The ophthalmic apparatus (1500a, 1500b) according to the embodiment includes a measurement system (OCT optical system 1101, OCT optical system 8) that acquires complex OCT data by performing optical coherence tomography on the subject's eye, and any of the ophthalmic information processing devices described above.

[0316] According to this aspect, an ophthalmic apparatus can be provided that can acquire OCT data through simple processing that is not affected by phase changes due to movement of the subject's eye or phase instability within the OCT measurement system.

[0317] An ophthalmologic information processing method according to an embodiment includes a generating step, an extracting step, and a phase correcting step. The generating step generates a phase difference profile by averaging, in the depth direction, phase differences calculated for each depth position of an A line between two adjacent B frames of complex OCT data of the subject's eye (E). The extracting step extracts a phase drift from the phase difference profile generated in the generating step. The phase correcting step corrects the phase of first complex OCT data of one of the two B frames based on the phase drift extracted in the extracting step.

[0318] According to this aspect, OCT data that is not affected by phase changes due to movement of the subject's eye or phase instability within the OCT measurement system can be acquired through simple processing, thereby improving the accuracy of phase information obtained from the OCT data.

[0319] Some embodiments include a removal step of removing unreliable phase difference data from the phase difference profile, and an extraction step of extracting a phase drift in which local phase difference changes have been removed from the phase difference profile from which the unreliable phase difference data has been removed in the removal step.

[0320] According to this embodiment, it is possible to acquire OCT data that is robust against local phase noise.

[0321] In some embodiments, the unreliable phase difference data includes at least one of data in which the signal strength is below a predetermined threshold level and data in which the contribution from the phase difference at a predetermined depth position in the averaging process exceeds a predetermined threshold.

[0322] According to this embodiment, OCT data that is robust to local phase noise can be acquired through simple processing.

[0323] In some embodiments, the extracting step extracts the phase drift by performing at least one of smoothing, polynomial fitting, and high-frequency cut filtering on the phase difference profile.

[0324] According to this aspect, OCT data that is not affected by phase changes due to movement of the subject's eye or phase instability within the OCT measurement system can be acquired through even simpler processing.

[0325] In some embodiments, at least one parameter of the smoothing process, the polynomial fitting, and the high-frequency cut filter process is set based on at least one of the frequency of the phase change of the measurement system that acquires the complex OCT data, the speed of the phase change, and the time required for the OCT scan in the measurement system.

[0326] According to this embodiment, it is possible to extract the phase drift under optimal conditions corresponding to the environment in which the complex OCT data is acquired.

[0327] In some embodiments, for adjacent first and second B frames, the phase of the complex OCT data of the second B frame is corrected based on the phase difference profile generated in the generation step, and then for the second B frame and a third B frame adjacent to the second B frame, the phase of the complex OCT data of the third B frame is corrected based on the phase difference profile generated in the generation step.

[0328] According to this aspect, it is possible to stabilize the phase of three-dimensional complex OCT data with simple processing.

[0329] Some embodiments include an image forming step of forming an OCT image of the subject's eye based on the complex OCT data of the subject's eye in which the complex OCT data of the at least one B frame has been corrected in the phase correcting step.

[0330] According to this aspect, it is possible to form an OCT image that is robust against phase changes caused by movement of the subject's eye or phase instability within the OCT measurement system.

[0331] A program according to the embodiment causes a computer to execute each step of any of the above-described ophthalmologic information processing methods.

[0332] According to this aspect, OCT data that is not affected by phase changes due to movement of the subject's eye or phase instability within the OCT measurement system can be acquired through simple processing, thereby improving the accuracy of phase information obtained from the OCT data.

[0333] <Other> In the above embodiment, a case where a swept-source type OCT is used has been described, but a spectral-domain type OCT may also be used. In this case, a low-coherence light source (such as an SLD light source) is used instead of the wavelength-swept light source in the light source unit 101, and a spectroscope and an image sensor (such as a CCD) are used instead of the detector 125 in the interference optical system.

[0334] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the inventions and their equivalents as set forth in the claims. [Explanation of symbols]

[0335] 8, 1101 OCT optical system 100 OCT units 210 Control Unit 211 Main control unit 212 Storage section 220 Image forming unit 230 Data Processing Unit 231 Phase stabilization section 231A Phase difference profile generator 231B Phase Drift Extraction Unit 231C Phase difference data removal section 231D Phase correction section 234 Aberration Correction Unit 300 Filter information search unit 1000, 1000a, 1000b Ophthalmic Systems 1111 Refractive power measurement optical system 1200 Ophthalmology Information Processing Device 1200a, 1200b Ophthalmology Information Processing Department 1500a, 1500b ophthalmology equipment E. Examined eye

Claims

1. a generation unit that generates a phase difference profile by performing averaging processing in a depth direction on phase differences calculated for each depth position of an A line between two adjacent B frames of complex OCT data of the subject's eye; an extractor that extracts a phase drift from the phase difference profile generated by the generator; a phase corrector that corrects a phase of the first complex OCT data of one of the two B frames based on the phase drift extracted by the extractor; An ophthalmology information processing device comprising:

2. a removal unit that removes unreliable phase difference data from the phase difference profile, The extraction unit extracts the phase drift from which local phase difference changes have been removed, from the phase difference profile from which the unreliable phase difference data has been removed by the removal unit.

2. The ophthalmological information processing apparatus according to claim 1.

3. The unreliable phase difference data includes at least one of data in which the signal strength is less than a predetermined threshold level and data in which the contribution of the phase difference at a predetermined depth position in the averaging process exceeds a predetermined threshold.

3. The ophthalmologic information processing apparatus according to claim 2.

4. The extraction unit extracts the phase drift by performing at least one of smoothing, polynomial fitting, and high-frequency cut filter processing on the phase difference profile.

4. The ophthalmologic information processing apparatus according to claim 1, wherein the ophthalmologic information processing apparatus is a computer.

5. At least one parameter of the smoothing process, the polynomial fitting, and the high frequency cut filter process is set based on at least one of a frequency of a phase change of a measurement system that acquires the complex OCT data, a speed of the phase change, and a time required for an OCT scan in the measurement system.

5. The ophthalmologic information processing apparatus according to claim 4.

6. For adjacent first and second B frames, after correcting the phase of the complex OCT data of the second B frame based on the phase difference profile generated by the generation unit, For the second B frame and a third B frame adjacent to the second B frame, a phase of the complex OCT data of the third B frame is corrected based on the phase difference profile generated by the generation unit.

6. The ophthalmologic information processing apparatus according to claim 1, wherein the ophthalmologic information processing apparatus is a computer.

7. and an image forming unit that forms an OCT image of the subject's eye based on the complex OCT data of the subject's eye obtained by correcting the complex OCT data of at least one B frame by the phase correcting unit.

7. The ophthalmologic information processing apparatus according to claim 1, wherein the ophthalmologic information processing apparatus is a computer.

8. a measurement system that acquires complex OCT data by performing optical coherence tomography on the subject's eye; An ophthalmological information processing device according to any one of claims 1 to 7; 1. An ophthalmic device comprising:

9. a generating step of generating a phase difference profile by averaging the phase differences calculated for each depth position of the A line between two adjacent B frames of the complex OCT data of the subject's eye in the depth direction; an extraction step of extracting a phase drift from the phase difference profile generated in the generation step; a phase correction step of correcting a phase of the first complex OCT data of one of the two B frames based on the phase drift extracted in the extraction step; An ophthalmological information processing method, comprising:

10. a removal step of removing unreliable phase difference data from the phase difference profile; The extraction step extracts the phase drift from the phase difference profile from which the unreliable phase difference data has been removed in the removal step, with local phase difference changes removed.

10. The ophthalmologic information processing method according to claim 9.

11. The unreliable phase difference data includes at least one of data in which the signal strength is less than a predetermined threshold level and data in which the contribution of the phase difference at a predetermined depth position in the averaging process exceeds a predetermined threshold. The ophthalmologic information processing method according to claim 10 .

12. The extraction step extracts the phase drift by performing at least one of smoothing, polynomial fitting, and high-frequency cut filter processing on the phase difference profile. The ophthalmologic information processing method according to any one of claims 9 to 11.

13. At least one parameter of the smoothing process, the polynomial fitting, and the high frequency cut filter process is set based on at least one of a frequency of a phase change of a measurement system that acquires the complex OCT data, a speed of the phase change, and a time required for an OCT scan in the measurement system.

13. The ophthalmologic information processing method according to claim 12.

14. For adjacent first and second B frames, after correcting the phase of the complex OCT data of the second B frame based on the phase difference profile generated in the generating step, For the second B frame and a third B frame adjacent to the second B frame, correcting the phase of the complex OCT data of the third B frame based on the phase difference profile generated in the generating step. The ophthalmologic information processing method according to any one of claims 9 to 13.

15. and an image forming step of forming an OCT image of the subject's eye based on the complex OCT data of the subject's eye obtained by correcting the complex OCT data of at least one B frame in the phase correcting step. The ophthalmologic information processing method according to any one of claims 9 to 14.

16. A program causing a computer to execute each step of the ophthalmologic information processing method according to any one of claims 9 to 15.

Images