Ophthalmologic information processing device, ophthalmologic apparatus, ophthalmologic information processing method, and program

Abstract

To provide a novel technique to accurately identify a layer region in a tomographic structure of a subject eye while reducing a labor.SOLUTION: An ophthalmologic information processing device comprises an acquisition part, a segmentation processing part, and a display control part. The acquisition part acquires image data of a first tomographic image obtained by executing optical coherence tomography on a subject eye. The segmentation processing part applies segmentation processing to the first tomographic image based on the image data to identify a boundary of a layer region in a depth direction. The display control part causes display means to identifiably display the boundary identified by the segmentation processing part and one or more pieces of boundary candidate information indicating boundary correction candidates.SELECTED DRAWING: Figure 6B

Description

Technical Field

[0001] This invention relates to an ophthalmic information processing apparatus, an ophthalmic apparatus, an ophthalmic information processing method, and a program.

Background Art

[0002] An Optical Coherence Tomography (OCT) apparatus that forms an image representing the surface morphology or internal morphology of a measurement object using a light beam from a laser light source or the like is known. Since OCT performed in an OCT apparatus has no invasiveness to a living body, its application in the medical field and the biological field is particularly expected to expand. For example, in the ophthalmic field, apparatuses for forming images of the fundus, cornea, etc. have been put into practical use. An apparatus using such an OCT technique (OCT apparatus) is applicable to the observation of the tomographic structure of various parts of an eye to be examined. In addition, since high-definition images can be acquired, it is applied to the diagnosis of various ophthalmic diseases.

[0003] For the observation of the tomographic structure of an eye to be examined, it is useful to perform segmentation (region division) processing on an OCT image acquired using OCT to identify layer regions constituting the tomographic structure. For example, the relationship between the thickness in the depth direction of a specific one or more layer regions and a disease is known, and the layer thickness analysis of the layer regions can be used as a biomarker. For example, by generating an en-face image of a desired one or more layer regions, the state of blood vessels, photoreceptor cells, etc. in the region can be observed in detail.

[0004] Various techniques related to such segmentation have been proposed. For example, Patent Document 1 discloses a technique for suitably setting a region of interest using segmentation results for an OCT image or an OCT angiography (OCTA) image.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the segmentation process for OCT images, it is often impossible to appropriately divide the layer regions depending on the image quality of the OCT images. In particular, when the eye to be examined is a diseased eye, although more detailed observation is required, the fact is that there are many cases where the layer regions cannot be appropriately divided.

[0007] In this case, a doctor or the like has to manually correct the boundaries of the layer regions identified by the segmentation process. For example, when performing OCT imaging of multiple slices by raster scanning, a doctor or the like has to manually correct the boundaries of the layer regions for each slice, consuming a very large amount of labor. When the image quality of the OCT image is low, it becomes even more difficult for a doctor or the like to accurately correct the boundaries of the layer regions.

[0008] As described above, currently, it may be difficult to accurately identify the layer regions in the tomographic structure of the eye to be examined.

[0009] The present invention has been made in view of such circumstances, and one of its purposes is to provide a new technique for accurately identifying the layer regions in the tomographic structure of the eye to be examined while reducing the labor.

Means for Solving the Problems

[0010] One aspect of an embodiment includes an acquisition unit that acquires image data of a first tomographic image obtained by performing optical coherence tomography on an eye to be examined, a segmentation processing unit that identifies boundaries of layer regions in the depth direction by performing segmentation processing on the first tomographic image based on the image data, and a display control unit that causes a display means to display, in a distinguishable manner, the boundaries of the layer regions identified by the segmentation processing unit and one or more boundary candidate information indicating candidates for correcting the boundaries. It is an ophthalmic information processing device.

[0011] Another aspect of the embodiment includes an optical system that performs optical coherence tomography on the eye to be examined, an image forming unit that forms the first tomographic image based on a detection result of interference light obtained by the optical system, and the above-described ophthalmic information processing device. It is an ophthalmic device.

[0012] Yet another aspect of the embodiment includes an acquisition step of acquiring image data of a first tomographic image obtained by performing optical coherence tomography on an eye to be examined, a segmentation processing step of identifying boundaries of layer regions in the depth direction by performing segmentation processing on the first tomographic image based on the image data, and a display control step of causing a display means to display, in a distinguishable manner, the boundaries of the layer regions identified in the segmentation processing step and one or more boundary candidate information indicating candidates for correcting the boundaries. It is an ophthalmic information processing method.

[0013] Yet another aspect of the embodiment is a program that causes a computer to execute each step of the above-described ophthalmic information processing method.

Advantages of the Invention

[0014] According to the embodiment of the present invention, it becomes possible to provide a new technique for accurately identifying layer regions in the tomographic structure of an eye to be examined while reducing labor.

Brief Description of the Drawings

[0015]

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Mode for Carrying Out the Invention

[0016] Examples of embodiments of an ophthalmic information processing apparatus, an ophthalmic apparatus, an ophthalmic information processing method, and a program according to the present invention will be described in detail with reference to the drawings. Note that the description contents of documents cited in this specification and any known techniques can be incorporated into the following embodiments.

[0017] The ophthalmic information processing apparatus according to the embodiment includes an acquisition unit, a segmentation processing unit, and a display control unit. The acquisition unit acquires image data of a first tomographic image obtained by performing optical coherence tomography (OCT) on an eye to be examined. The segmentation processing unit specifies the boundaries of layer regions in the depth direction by performing segmentation processing on the first tomographic image based on the above image data. The display control unit causes a display means to display, in a distinguishable manner, the boundaries of the layer regions specified by the segmentation processing unit and one or more boundary candidate information indicating candidates for correcting the boundaries of the layer regions.

[0018] In some embodiments, the acquisition unit acquires image data of the first tomographic image from outside the ophthalmic information processing apparatus via a network. That is, the ophthalmic information processing apparatus according to the embodiment is configured to acquire image data of the first tomographic image from outside the ophthalmic information processing apparatus.

[0019] In some embodiments, the acquisition unit acquires a detection result of interference light by performing an OCT scan (OCT imaging, OCT measurement) on the eye to be examined using an optical system, and forms a first tomographic image based on the acquired detection result of interference light to acquire image data of the first tomographic image. In this case, an ophthalmic apparatus including an optical system realizes the functions of the ophthalmic information processing apparatus according to the embodiment.

[0020] Boundary candidate information is information representing one or more correction candidates for the boundary of a layer region specified by a segmentation processing unit. The boundary of the layer region according to the embodiment may be a linear boundary defining two layer regions adjacent in the depth direction, or a region having a width in the depth direction and defining two layer regions adjacent in the depth direction. The information representing the correction candidate according to the embodiment may be represented by a straight line, a curve, or a region having a width in the depth direction that defines two layer regions adjacent in the depth direction.

[0021] The boundary candidate information may include information representing, as a correction candidate, a boundary selected from among a plurality of boundary candidates of one layer region obtained in the segmentation process for the first tomographic image. Further, the boundary candidate information may include information representing, as a correction candidate, a boundary determined based on the boundary of a layer region obtained by segmentation processing for a tomographic image of an eye to be examined acquired in the past. Furthermore, the boundary candidate information may include information representing, as a correction candidate, a boundary determined based on the boundary of a layer region obtained by segmentation processing for a second tomographic image that is another slice image of an eye to be examined different from the first tomographic image.

[0022] Examples of depicting distinguishable boundaries include depicting a boundary in a color or luminance different from other boundaries, depicting a boundary using a line or curve thicker (or thinner) than other boundaries, depicting a boundary with a luminance that changes temporally (e.g., blinks) in a manner different from other boundaries, and attaching information (such as characters, arrows) indicating the boundary.

[0023] According to the embodiment, it becomes possible to observe in detail the boundary specified by the segmentation process in the first tomographic image while referring to one or more pieces of boundary candidate information. For example, while referring to one or more pieces of boundary candidate information, it becomes possible to observe the position of the boundary specified by the segmentation process or correct the above boundary. As a result, it becomes possible to specify the layer region in the tomographic structure of the eye to be examined with high accuracy while reducing the labor.

[0024] In some embodiments, the display control unit causes the display means to display, by superposing, an OCT image in which a boundary is depicted by segmentation processing and one or more boundary candidate information. In some embodiments, the one or more boundary candidate information are images representing a plurality of correction candidates, and the display control unit causes the display means to display the images representing the plurality of correction candidates in parallel or by superposition. In some embodiments, the display control unit causes the display means to display, in different manners, each of the boundaries of the layer regions specified by the segmentation processing unit and the one or more boundary candidate information. As a result, it becomes possible to easily identify the boundary of the layer region to be corrected in the first tomographic image from the boundary of the layer region in the one or more boundary candidate information.

[0025] In some embodiments, the ophthalmic information processing apparatus includes an operation unit and a correction processing unit. The correction processing unit executes correction processing for correcting the boundary of the layer region in the first tomographic image based on the user operation information for the operation unit. The correction processing changes the positions of one or more pixels constituting the boundary of the layer region before correction in the first tomographic image based on the operation information, and sets the boundary defined by the one or more pixels whose positions have been changed as the boundary of the new corrected layer region in the first tomographic image.

[0026] The ophthalmic information processing method according to the embodiment is a method for controlling the ophthalmic information processing apparatus according to the embodiment. The program according to the embodiment causes a computer (processor) to execute each step of the ophthalmic information processing method according to the embodiment. That is, the program according to the embodiment is a computer program including instructions that cause a computer to execute the ophthalmic information processing method according to the embodiment when the program is executed by the computer. The recording medium (storage medium) according to the embodiment is any non-transitory computer-readable recording medium on which the program according to the embodiment is recorded (stored). The recording medium may be an electronic medium using magnetism, light, magneto-optics, semiconductors, etc. Typically, the recording medium is a magnetic tape, magnetic disk, optical disk, magneto-optical disk, flash memory, solid state drive, etc. Also, it is possible to transmit and receive this program through a network such as the Internet or a LAN.

[0027] In this specification, the processor includes circuits such as, for example, a CPU (Central Processing Unit), GPU (Graphics Processing Unit), ASIC (Application Specific Integrated Circuit), programmable logic device (for example, SPLD (Simple Programmable Logic Device), CPLD (Complex Programmable Logic Device), FPGA (Field Programmable Gate Array)). The processor realizes the functions according to the embodiment, for example, by reading and executing a program stored in a memory circuit or a storage device. The memory circuit or the storage device may be included in the processor. Also, the memory circuit or the storage device may be provided outside the processor.

[0028] Hereinafter, a case where an ophthalmic apparatus capable of acquiring an OCT image, which is a tomographic image of an eye to be examined, realizes the functions of the ophthalmic information processing apparatus according to the embodiment will be described as an example. However, the ophthalmic information processing apparatus according to the embodiment may be provided outside the ophthalmic apparatus, and the ophthalmic information processing apparatus may be configured to acquire a tomographic image (OCT image) from the ophthalmic apparatus.

[0029] The ophthalmic apparatus according to the embodiment can perform OCT on an arbitrary part of the eye to be examined, such as the fundus oculi or the anterior segment of the eye. In this specification, the images acquired by OCT may be collectively referred to as OCT images. At this time, unless otherwise specified, the OCT images will be described as tomographic images (slice images). Also, the measurement operation for forming the OCT image may be referred to as OCT measurement.

[0030] Hereinafter, in the embodiment, the case of using the swept-source type OCT method in the measurement or imaging using OCT will be described in particular detail. However, the configuration according to the embodiment can also be applied to an ophthalmic apparatus using other types (for example, spectral domain type or time domain type) of OCT.

[0031] [Configuration] As shown in FIGS. 1 and 2, the ophthalmic apparatus 1 according to the embodiment includes a fundus camera unit 2, an OCT unit 100, and an arithmetic control unit 200. The fundus camera unit 2 has an optical system substantially the same as that of a conventional fundus camera. The OCT unit 100 is provided with an optical system for acquiring an OCT image (for example, a tomographic image) of the fundus oculi (or the anterior segment of the eye). The arithmetic control unit 200 includes a computer that executes various arithmetic processes, control processes, and the like.

[0032] [Fundus Camera Unit 2] The fundus camera unit 2 shown in Fig. 1 is provided with an optical system for acquiring a two-dimensional image (fundus image) representing the surface form of the fundus Ef of the eye E to be examined. The fundus image includes an observation image, a captured image, and the like. The observation image is, for example, a monochromatic moving image formed at a predetermined frame rate using near-infrared light. The captured image may be, for example, a color image obtained by flash-emitting visible light, or a monochromatic still image using near-infrared light or visible light as illumination light. The fundus camera unit 2 may be configured to be able to acquire other images, such as a fluorescein fluorescence image, an indocyanine green fluorescence image, and a spontaneous fluorescence image.

[0033] The fundus camera unit 2 is provided with a chin rest and a forehead rest for supporting the face of the subject. Further, the fundus camera unit 2 is provided with an illumination optical system 10 and a photographing optical system 30. The illumination optical system 10 irradiates the fundus Ef with illumination light. The photographing optical system 30 guides the fundus reflected light of this illumination light to an imaging device (CCD image sensors (sometimes simply referred to as CCDs) 35, 38). Further, the photographing optical system 30 guides the measurement light from the OCT unit 100 to the fundus Ef and guides the measurement light that has passed through the fundus Ef to the OCT unit 100.

[0034] The observation light source 11 of the illumination optical system 10 includes, for example, a halogen lamp. The light (observation illumination light) output from the observation light source 11 is reflected by a reflecting mirror 12 having a curved reflecting surface, passes through a condenser lens 13, and passes through a visible cut filter 14 to become near-infrared light. Further, the observation illumination light is once focused in the vicinity of the photographing light source 15, reflected by a mirror 16, and passes through relay lenses 17, 18, an aperture 19, and a relay lens 20. Then, the observation illumination light is reflected at the peripheral portion (the region around the hole portion) of the aperture mirror 21, passes through a dichroic mirror 48, and is refracted by an objective lens 22 to illuminate the fundus Ef. Note that an LED (Light Emitting Diode) can also be used as the observation light source.

[0035] The fundus reflected light of the observation illumination light is refracted by the objective lens 22, transmitted through the dichroic mirror 48, passes through the hole formed in the central region of the aperture mirror 21, transmitted through the dichroic mirror 55, passes through the focusing lens 31, and is reflected by the mirror 32. Further, this fundus reflected light is transmitted through the half mirror 33A, reflected by the dichroic mirror 33, and imaged on the light receiving surface of the CCD image sensor 35 by the condenser lens 34. The CCD image sensor 35 detects the fundus reflected light, for example, at a predetermined frame rate. An image (observation image) based on the fundus reflected light detected by the CCD image sensor 35 is displayed on the display device 3. When the focus of the imaging optical system 30 is adjusted to the anterior eye part, an observation image of the anterior eye part of the subject eye E is displayed.

[0036] The imaging light source 15 includes, for example, a xenon lamp. The light (imaging illumination light) output from the imaging light source 15 is irradiated onto the fundus Ef through the same path as the observation illumination light. The fundus reflected light of the imaging illumination light is guided to the dichroic mirror 33 through the same path as that of the observation illumination light, transmitted through the dichroic mirror 33, reflected by the mirror 36, and imaged on the light receiving surface of the CCD image sensor 38 by the condenser lens 37. An image (imaging image) based on the fundus reflected light detected by the CCD image sensor 38 is displayed on the display device 3. The display device 3 for displaying the observation image and the display device 3 for displaying the imaging image may be the same or different. Also, when the subject eye E is illuminated with infrared light for the same imaging, an infrared imaging image is displayed. It is also possible to use an LED as the imaging light source.

[0037] The LCD (Liquid Crystal Display) 39 displays a fixation target and a visual acuity measurement target. The fixation target is a target for fixing the subject eye E and is used during fundus imaging, OCT measurement, etc.

[0038] A part of the light output from the LCD 39 is reflected by the half mirror 33A, then reflected by the mirror 32, passes through the aperture of the aperture mirror 21 via the focusing lens 31 and the dichroic mirror 55. The light that has passed through the aperture is transmitted through the dichroic mirror 48, refracted by the objective lens 22, and projected onto the fundus Ef.

[0039] By changing the display position of the fixation mark on the screen of the LCD 39, the fixation position of the eye under examination E can be changed. Examples of the fixation position of the eye under examination E include positions for acquiring an image centered on the macula of the fundus Ef, positions for acquiring an image centered on the optic disc, and positions for acquiring an image centered on the fundus center between the macula and the optic disc. Also, it is possible to arbitrarily change the display position of the fixation mark.

[0040] Furthermore, the fundus camera unit 2 is provided with an alignment optical system 50 and a focus optical system 60, similar to a conventional fundus camera. The alignment optical system 50 generates an index (alignment index) for aligning the device optical system with respect to the eye under examination E. The focus optical system 60 generates an index (split index) for focusing on the fundus Ef.

[0041] The light (alignment light) output from the LED 51 of the alignment optical system 50 passes through the diaphragms 52, 53 and the relay lens 54, is reflected by the dichroic mirror 55, and passes through the aperture of the aperture mirror 21. The light that has passed through the aperture is transmitted through the dichroic mirror 48 and projected onto the cornea of the eye under examination E by the objective lens 22.

[0042] The corneal reflection light of the alignment light passes through the objective lens 22, the dichroic mirror 48, and the above-mentioned hole portion. A part of it passes through the dichroic mirror 55, passes through the focusing lens 31, is reflected by the mirror 32, and passes through the half mirror 33A. The corneal reflection light that has passed through the half mirror 33A is reflected by the dichroic mirror 33 and projected onto the light receiving surface of the CCD image sensor 35 by the condenser lens 34. The light receiving image (alignment index) by the CCD image sensor 35 is displayed on the display device 3 together with the observation image. The user performs alignment by performing the same operation as a conventional fundus camera. Also, the arithmetic control unit 200 may perform alignment by analyzing the position of the alignment index and moving the optical system (auto-alignment function).

[0043] When performing focus adjustment, the reflecting surface of the reflecting rod 67 is obliquely provided on the optical path of the illumination optical system 10. The light (focus light) output from the LED 61 of the focus optical system 60 passes through the relay lens 62, is separated into two light beams by the split index plate 63, passes through the two-hole diaphragm 64, and is reflected by the mirror 65. The light reflected by the mirror 65 is once imaged and reflected on the reflecting surface of the reflecting rod 67 by the condenser lens 66. Further, the focus light passes through the relay lens 20, is reflected by the aperture mirror 21, passes through the dichroic mirror 48, is refracted by the objective lens 22, and is projected onto the fundus Ef.

[0044] The fundus reflection light of the focus light is detected by the CCD image sensor 35 through the same path as the corneal reflection light of the alignment light. The light receiving image (split index) by the CCD image sensor 35 is displayed on the display device 3 together with the observation image. The arithmetic control unit 200 analyzes the position of the split index and moves the focusing lens 31 and the focus optical system 60 to perform focusing in the same manner as in the conventional case (auto-focus function). Also, focusing may be performed manually while visually recognizing the split index.

[0045] The dichroic mirror 48 branches the optical path for OCT measurement from the optical path for fundus imaging. The dichroic mirror 48 reflects light in the wavelength band used for OCT measurement and transmits light for fundus imaging. In the optical path for OCT measurement, a collimating lens unit 40, an optical path length changing unit 41, an optical scanner 42, a collimating lens 43, a mirror 44, an OCT focusing lens 45, and a field lens 46 are provided in order from the OCT unit 100 side.

[0046] The optical path length changing unit 41 is configured to be movable in the direction of the arrow shown in FIG. 1 and changes the optical path length of the optical path for OCT measurement. This change in the optical path length is used for correcting the optical path length according to the axial length of the eye to be examined E and adjusting the interference state. The optical path length changing unit 41 includes, for example, a corner cube and a mechanism for moving the same.

[0047] The optical scanner 42 is disposed at a position (pupil conjugate position) optically conjugate to the pupil of the eye to be examined or in the vicinity thereof. The optical scanner 42 changes the traveling direction of light (measurement light) passing through the optical path for OCT measurement. The optical scanner 42 can deflect the measurement light one-dimensionally or two-dimensionally under the control from the arithmetic control unit 200 described later.

[0048] The optical scanner 42 includes, for example, a first galvanometer mirror, a second galvanometer mirror, and a mechanism for independently driving them. The first galvanometer mirror deflects the measurement light LS so as to scan the imaging site (fundus Ef or anterior eye segment) in the horizontal direction (x direction) orthogonal to the optical axis of the interference optical system. The second galvanometer mirror deflects the measurement light LS deflected by the first galvanometer mirror so as to scan the imaging site in the vertical direction (y direction) orthogonal to the optical axis of the interference optical system. Thereby, the imaging site can be scanned in an arbitrary direction on the xy plane with the measurement light LS.

[0049] For example, by simultaneously controlling the orientation of the first galvanometer mirror and the orientation of the second galvanometer mirror included in the optical scanner 42, it is possible to move the irradiation position of the measurement light along an arbitrary locus on the xy plane. Thereby, the imaging site can be scanned according to a desired scan pattern.

[0050] The OCT focusing lens 45 is movable along the optical path of the measurement light LS (the optical axis of the interference optical system). The OCT focusing lens 45 moves along the optical path of the measurement light LS under the control from the arithmetic control unit 200 described later.

[0051] In some embodiments, a liquid crystal lens or an acousto-optic lens is provided instead of the OCT focusing lens 45. The liquid crystal lens or the acousto-optic lens is controlled by the arithmetic control unit 200 in the same manner as the OCT focusing lens 45.

[0052] 〔OCT Unit 100〕 An example of the configuration of the OCT unit 100 will be described with reference to FIG. 2. The OCT unit 100 is provided with an optical system for performing OCT on the fundus Ef. This optical system is an interference optical system that splits the light from a wavelength-scanning (wavelength-sweeping) light source into measurement light and reference light, causes the measurement light that has passed through the fundus Ef and the reference light that has passed through the reference optical path to interfere to generate interference light, and detects this interference light. The detection result (detection signal) of the interference light in the interference optical system is a signal indicating the spectrum of the interference light, and is sent to the arithmetic control unit 200.

[0053] The light source unit 101 is configured to include a wavelength-scanning (wavelength-sweeping) light source capable of scanning (sweeping) the wavelength of the emitted light, similar to a general swept-source type OCT apparatus. The light source unit 101 changes the output wavelength temporally in the near-infrared wavelength band that is not visible to the human eye.

[0054] The light L0 output from the light source unit 101 is guided by the optical fiber 102 to the polarization controller 103, and its polarization state is adjusted. The polarization controller 103 adjusts the polarization state of the light L0 guided in the optical fiber 102, for example, by applying an external stress to the loop-shaped optical fiber 102.

[0055] The light L0 whose polarization state has been adjusted by the polarization controller 103 is guided by the optical fiber 104 to the fiber coupler 105 and split into the measurement light LS and the reference light LR.

[0056] The reference light LR is guided by the optical fiber 110 to the collimator 111 and becomes a parallel light beam. The reference light LR that has become a parallel light beam passes through the optical path length correction member 112 and the dispersion compensation member 113 and is guided to the corner cube 114. The optical path length correction member 112 acts as a delay means for matching the optical path lengths (optical distances) of the reference light LR and the measurement light LS. The dispersion compensation member 113 acts as a dispersion compensation means for matching the dispersion characteristics of the reference light LR and the measurement light LS.

[0057] The corner cube 114 reverses the traveling direction of the reference light LR that has become a parallel light beam by the collimator 111. The optical path of the reference light LR incident on the corner cube 114 and the optical path of the reference light LR exiting from the corner cube 114 are parallel. Also, the corner cube 114 is movable in the direction along the incident optical path and the exiting optical path of the reference light LR. By this movement, the length of the optical path (reference optical path) of the reference light LR is changed.

[0058] The reference light LR that has passed through the corner cube 114 passes through the dispersion compensation member 113 and the optical path length correction member 112, is converted from a parallel light beam to a converging light beam by the collimator 116, and is incident on the optical fiber 117. The reference light LR incident on the optical fiber 117 is guided to the polarization controller 118, and the polarization state of the reference light LR is adjusted.

[0059] The polarization controller 118 has, for example, the same configuration as the polarization controller 103. The reference light LR whose polarization state is adjusted by the polarization controller 118 is guided to the attenuator 120 by the optical fiber 119, and the light amount is adjusted under the control of the arithmetic control unit 200. The reference light LR whose light amount is adjusted by the attenuator 120 is guided to the fiber coupler 122 by the optical fiber 121.

[0060] The measurement light LS generated by the fiber coupler 105 is guided by the optical fiber 127, and is made into a parallel light beam by the collimating lens unit 40. The measurement light LS made into a parallel light beam passes through the optical path length changing unit 41, the optical scanner 42, the collimating lens 43, the mirror 44, the OCT focusing lens 45, the field lens 46, and the VCC lens 47, and reaches the dichroic mirror 48. Then, the measurement light LS is reflected by the dichroic mirror 48, refracted by the objective lens 22, and irradiated onto the fundus Ef. The measurement light LS is scattered (including reflection) at various depth positions of the fundus Ef. The backscattered light of the measurement light LS by the fundus Ef travels in the reverse direction along the same path as the forward path, is guided to the fiber coupler 105, and reaches the fiber coupler 122 via the optical fiber 128.

[0061] The fiber coupler 122 combines (interferes) the measurement light LS incident via the optical fiber 128 and the reference light LR incident via the optical fiber 121 to generate interference light. The fiber coupler 122 generates a pair of interference lights LC by branching the interference light of the measurement light LS and the reference light LR at a predetermined branching ratio (for example, 50:50). The pair of interference lights LC emitted from the fiber coupler 122 are respectively guided to the detector 125 by the optical fibers 123 and 124.

[0062] Detector 125 has, for example, a pair of photo-detectors that respectively detect a pair of interference lights LC, and is a balanced photo diode that outputs the difference between the detection results by these. Detector 125 sends its detection result (detection signal) to arithmetic control unit 200. Arithmetic control unit 200 forms a tomographic image as an OCT image by performing Fourier transform or the like on the spectral distribution based on the detection result obtained by detector 125, for example, for each series of wavelength scans (for each A-line). Arithmetic control unit 200 causes the formed image to be displayed on display device 3.

[0063] In this embodiment, a Michelson interferometer is adopted, but any type of interferometer such as a Mach-Zehnder type can be appropriately adopted. In this embodiment, in addition to the configuration shown in FIG. 2, the interference optical system may include collimating lens unit 40, optical path length changing unit 41, optical scanner 42, collimating lens 43, mirror 44, OCT focusing lens 45, and field lens 46 shown in FIG. 1. This interference optical system is an example of the "interference optical system" according to the embodiment.

[0064] 〔Arithmetic control unit 200〕 The configuration of arithmetic control unit 200 will be described.

[0065] FIGS. 3 to 5 show block diagrams of configuration examples of the processing system (control system) of ophthalmic apparatus 1 according to the embodiment. FIG. 4 is a functional block diagram of a configuration example of data processing unit 230 in FIG. 3. FIG. 5 is a functional block diagram of a configuration example of segmentation processing unit 232 in FIG. 4. In FIGS. 3 to 5, the same parts as those in FIG. 1 or FIG. 2 are denoted by the same reference numerals, and the description is appropriately omitted.

[0066] Arithmetic control unit 200 analyzes the detection signal input from detector 125 to form an OCT image of fundus Ef (or anterior eye segment). The arithmetic processing for forming the OCT image is the same as that of a conventional swept-source type OCT apparatus.

[0067] As shown in FIG. 3, the arithmetic control unit 200 includes a control unit 210 and controls each of the fundus camera unit 2, the display device 3, and the OCT unit 100. For example, the arithmetic control unit 200 forms an OCT image of the fundus Ef and causes the formed image to be displayed on the display device 3 (display unit 240A described later).

[0068] As controls for the fundus camera unit 2, there are operation controls for the observation light source 11, the imaging light source 15, and the LEDs 51 and 61, operation controls for the CCD image sensors 35 and 38, operation control for the LCD 39, movement control for the focusing lens 31, movement control for the OCT focusing lens 45, movement control for the reflecting rod 67, operation control for the alignment optical system 50, movement control for the focusing optical system 60, movement control for the optical path length changing unit 41, operation control for the optical scanner 42, and the like.

[0069] As controls for the OCT unit 100, there are operation control for the light source unit 101, movement control for the corner cube 114, operation control for the detector 125, operation control for the attenuator 120, operation control for the polarization controllers 103 and 118, and the like.

[0070] The arithmetic control unit 200 is configured to include, for example, a processor, a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk drive, a communication interface, and the like, similar to a conventional computer. A computer program for controlling the ophthalmic device 1 is stored in a storage device such as a hard disk drive. The arithmetic control unit 200 may include various circuit boards, for example, a circuit board for forming an OCT image. Further, the arithmetic control unit 200 may include an operation device (input device) such as a keyboard or a mouse, and a display device such as an LCD. In some embodiments, the functions of the arithmetic control unit 200 are realized by one or more processors.

[0071] The fundus camera unit 2, the display device 3, the OCT unit 100, and the arithmetic control unit 200 may be integrally configured (i.e., within a single housing), or may be separately configured in two or more housings.

[0072] The control unit 210 includes a main control unit 211 and a storage unit 212.

[0073] (Main control unit 211) The main control unit 211 performs various controls by outputting control signals to each part of the aforementioned ophthalmic apparatus 1. In particular, the main control unit 211 controls the CCD image sensors 35, 38, the LCD 39, the focusing drive unit 31A, the optical path length changing unit 41, the optical scanner 42, and the OCT focusing drive unit 45A with respect to the fundus camera unit 2. Further, the main control unit 211 controls the light source unit 101, the reference drive unit 114A, the polarization controllers 103, 118, the attenuator 120, and the detector 125 with respect to the OCT unit 100.

[0074] The main control unit 211 controls the exposure time (charge accumulation time), sensitivity, frame rate, etc. of the CCD image sensor 35 or the CCD image sensor 38. In some embodiments, the main control unit 211 controls the CCD image sensor 35 or the CCD image sensor 38 so as to acquire an image with a desired image quality.

[0075] The main control unit 211 performs display control of a fixation mark and a visual acuity measurement target on the LCD 39. Thereby, the target presented to the eye E to be examined is switched, or the type of the target is changed. Also, by changing the display position of the target on the LCD 39, it is possible to change the target presentation position with respect to the eye E to be examined.

[0076] The focusing drive unit 31A moves the focusing lens 31 in the optical axis direction. The main control unit 211 controls the focusing drive unit 31A so that the focusing lens 31 is disposed at a desired focusing position. Thereby, the focusing position of the imaging optical system 30 is changed.

[0077] For example, the main control unit 211 analyzes the position of the split index in the received light image obtained by the CCD image sensor 35, and controls the focusing drive unit 31A and the focus optical system 60. Alternatively, for example, while the main control unit 211 causes the live image of the eye E to be displayed on the display unit 240A described later, the main control unit 211 controls the focusing drive unit 31A and the focus optical system 60 according to the operation performed by the user on the operation unit 240B described later.

[0078] The main control unit 211 changes the optical path length of the measurement light LS by controlling the optical path length changing unit 41. Thereby, the difference between the optical path length of the measurement light LS and the optical path length of the reference light LR is changed.

[0079] For example, the main control unit 211 analyzes the detection result of the interference light LC obtained by OCT measurement (or the OCT image formed based on the detection result), and controls the optical path length changing unit 41 so that the measurement site reaches a desired depth position.

[0080] The main control unit 211 controls the optical scanner 42. The main control unit 211 controls the optical scanner 42 so as to deflect the measurement light LS according to a deflection pattern corresponding to a preset scan mode.

[0081] Examples of such scan modes include line scan, cross scan, circle scan, radial scan, concentric circle scan, multi-line cross scan, spiral scan (spiral scan), Lissajous scan, three-dimensional scan, ammonite scan, etc. The ammonite scan is a scan mode in which the scan reference position (scan center position) of the circle scan as the high-speed scan moves along the scan pattern of the spiral scan as the low-speed scan. That is, while moving the scan center position along the spiral scan pattern, a circle scan is sequentially executed around each scan center position.

[0082] By scanning the imaging site with the measurement light LS according to the deflection pattern corresponding to the scanning mode as described above, a tomographic image as an OCT image can be acquired on a plane spanned by the direction along the scan line (scan trajectory) and the fundus depth direction (z direction).

[0083] The OCT focusing drive unit 45A moves the OCT focusing lens 45 along the optical axis of the measurement light LS. The main control unit 211 controls the OCT focusing drive unit 45A so that the OCT focusing lens 45 is disposed at a desired focusing position. Thereby, the focusing position of the measurement light LS is changed. The focusing position of the measurement light LS corresponds to the depth position (z position) of the beam waist of the measurement light LS.

[0084] For example, the main control unit 211 controls the OCT focusing drive unit 45A based on the signal-to-noise ratio of the detection result of the interference light LC obtained by OCT measurement, or an evaluation value corresponding to the image quality of the OCT image formed based on the detection result (including the statistical value of the evaluation value).

[0085] When a liquid crystal lens or an acousto-optic lens is provided instead of the OCT focusing lens 45, the main control unit 211 can control the liquid crystal lens or the acousto-optic lens in the same manner as the control of the OCT focusing drive unit 45A.

[0086] The main control unit 211 controls the light source unit 101. The control of the light source unit 101 includes switching on and off of the light source, intensity control of the emitted light, change of the central frequency of the emitted light, change of the sweep speed of the emitted light, change of the sweep frequency, change of the sweep wavelength range, and the like.

[0087] The reference drive unit 114A moves the corner cube 114 provided in the optical path of the reference light along this optical path. Thereby, the difference between the optical path length of the measurement light LS and the optical path length of the reference light LR is changed.

[0088] For example, the main control unit 211 analyzes the detection result of the interference light LC obtained by OCT measurement (or the OCT image formed based on the detection result), and controls the reference drive unit 114A so that the measurement site is at a desired depth position. In some embodiments, only one of the optical path length changing unit 41 and the reference drive unit 114A is provided.

[0089] The main control unit 211 controls the polarization controllers 103 and 118. For example, the main control unit 211 controls the polarization controllers 103 and 118 based on the signal-to-noise ratio of the detection result of the interference light LC obtained by OCT measurement, or an evaluation value corresponding to the image quality of the OCT image formed based on the detection result (including the statistical value of the evaluation value).

[0090] The main control unit 211 controls the attenuator 120. For example, the main control unit 211 controls the attenuator 120 based on the signal-to-noise ratio of the detection result of the interference light LC obtained by OCT measurement, or an evaluation value corresponding to the image quality of the OCT image formed based on the detection result (including the statistical value of the evaluation value).

[0091] The main control unit 211 controls the detector 125. The control of the detector 125 includes control of the exposure time (charge accumulation time), sensitivity, frame rate, etc.

[0092] The moving mechanism 150 moves the fundus camera unit 2 (OCT unit 100) three-dimensionally relative to the eye to be examined E. For example, the main control unit 211 can control the moving mechanism 150 to move the optical system provided in the fundus camera unit 2 three-dimensionally. This control is used in alignment and tracking. Tracking is to move the device optical system in accordance with the movement of the eye to be examined E. When performing tracking, alignment and focusing are executed in advance. Tracking is a function that maintains a suitable positional relationship with alignment and focus by moving the device optical system in real time in accordance with the position and orientation of the eye to be examined E based on an image obtained by capturing a moving image of the eye to be examined E.

[0093] In some embodiments, the main control unit 211 corrects the position of the scan range for OCT imaging in real time based on the tracking information obtained by tracking control (tracking information obtained by causing the optical system (interference optical system) to follow the movement of the eye E to be examined). The main control unit 211 can control the optical scanner 42 to scan the corrected scan range with the measurement light LS.

[0094] Such a main control unit 211 includes a display control unit 211A. The display control unit 211A causes various information to be displayed on the display device 3 (or the display unit 240A described later). The information displayed on the display device 3 includes imaging results (observation images, OCT images), measurement results (measurement values), one or more boundary candidate information, and the like. For example, the display control unit 211A can cause the display device 3 or the display unit 240A to display an OCT image in which the boundary of the layer region specified by the segmentation process is drawn so as to be distinguishable, and one or more boundary candidate information.

[0095] The display control unit 211A can cause the display device 3 or the display unit 240A to display each of the boundary of the layer region specified by the segmentation process and one or more boundary candidate information in different manners. In this case, for example, they can be displayed in different colors, different luminances (or luminances that change over time), lines of different thicknesses, or lines of different modes (solid lines, broken lines, dotted lines, one-dot chain lines, two-dot chain lines, etc.).

[0096] Further, the main control unit 211 performs a process of writing data to the storage unit 212 and a process of reading data from the storage unit 212.

[0097] (Storage unit 212) The memory unit 212 stores various types of data. Examples of the data stored in the memory unit 212 include, for example, the detection result of interference light (scan data), OCT image data, fundus image data, boundary candidate information, and subject eye information. The subject eye information includes information about the subject such as patient ID and name, and information about the subject eye such as left eye / right eye identification information.

[0098] At least a part of the above data stored in the memory unit 212 may be stored in a memory unit provided outside the ophthalmic apparatus 1. For example, the ophthalmic apparatus 1 is communicably connected to a server apparatus having a function of storing at least a part of the above data via a network such as a hospital LAN (Local Area Network). Here, the ophthalmic apparatus 1 and the server apparatus may be connected via a WAN (Wide Area Network) such as the Internet. Further, the ophthalmic apparatus 1 and the server apparatus may be connected via a network combining LAN and WAN.

[0099] (Image forming unit 220) The image forming unit 220 forms image data of an OCT image (tomographic image) of the fundus Ef or the anterior segment of the eye based on the detection signal (interference signal, scan data) from the detector 125. That is, the image forming unit 220 forms an image of the subject eye E based on the detection result of interference light as an OCT image generation unit. This process includes processes such as noise removal (noise reduction), filtering, and FFT (Fast Fourier Transform) as in the conventional swept source type optical coherence tomography. The image data thus obtained is a data set including a group of image data formed by imaging the reflection intensity profiles in a plurality of A-lines (the paths of the respective measurement lights LS in the subject eye E).

[0100] In order to improve the image quality, a plurality of data sets collected by repeating scans in the same pattern a plurality of times can be superimposed (added and averaged).

[0101] The image forming unit 220 is configured to include, for example, the aforementioned circuit board. In this specification, "image data" and the "image" based thereon may be regarded as the same. Also, the part of the fundus Ef and its image may be regarded as the same.

[0102] In some embodiments, the functions of the image forming unit 220 are realized by an image forming processor.

[0103] (Data processing unit 230) The data processing unit 230 performs various data processing (image processing) and analysis processing on the detection result of the interference light LC or the image formed by the image forming unit 220. Examples of data processing include various correction processes such as luminance correction and variance correction of images. Examples of analysis processing include analysis of the signal-to-noise ratio of interference signals, segmentation processing, correction processing of segmentation processing results, registration processing, and tissue analysis processing in images.

[0104] As an example of segmentation processing, there is specific processing of a plurality of layer regions corresponding to a plurality of layer tissues of the fundus (retina, choroid, etc.) or the vitreous body. In the segmentation processing, the boundaries of the layer regions corresponding to the layer tissues are specified. Examples of the layer tissues to be specified include the layer tissues constituting the retina. The layer tissues constituting the retina include an inner limiting membrane (ILM), a nerve fiber layer (NFL), a ganglion cell layer (GCL), an inner plexiform layer (IPL), an inner nuclear layer (INL), an outer plexiform layer (OPL), an outer nuclear layer (ONL), an external limiting membrane (ELM), a photoreceptor layer, a retinal pigment epithelium (RPE), a choroid, a photoreceptor inner / outer segment junction (IS / OS) or an ellipsoid zone (EZ), and a chorio-scleral interface (CSI). In some embodiments, layer regions corresponding to layer tissues such as Bruch's membrane, choroid, sclera, or vitreous body are specified. For example, a layer region corresponding to the layer tissue for a predetermined number of pixels on the scleral side with respect to the RPE is defined as Bruch's membrane.

[0105] In addition, as an example of the segmentation processing, there are specific processing of the boundaries of at least one of the above layer regions and generation processing of one or more boundary candidate information indicating candidates for modifying the boundaries.

[0106] As an example of tissue analysis processing in an image, there are specific processing of a predetermined site such as a lesion or tissue, and analysis processing of the composition of a predetermined site. Examples of lesions include detached parts, edema, bleeding, leukoplakia, tumors, drusen, etc. Examples of tissues include blood vessels, optic nerve heads, fovea, macula, etc. Examples of analysis processing of the composition of a predetermined site include calculation of the distance (interlayer distance), area, angle, ratio, density between specified sites; calculation by a specified calculation formula; specification of the shape of a predetermined site; calculation of these statistical values; calculation of the distribution of measured values and statistical values; image processing based on these analysis processing results, etc.

[0107] In some embodiments, the data processing unit 230 performs specific identification of blood vessel walls, specific identification of blood vessel regions, specific identification of the connection relationship between two or more blood vessel regions, specific identification of the distribution of blood vessel regions, specific identification of blood flow, calculation of blood flow velocity, determination of arteries / veins, etc. by performing analysis processing on the OCTA image.

[0108] In addition, the data processing unit 230 can perform the above-described image processing and analysis processing on an image (fundus image, anterior eye image, etc.) obtained by the fundus camera unit 2.

[0109] Furthermore, the data processing unit 230 executes known image processing such as interpolation processing for interpolating pixels between two-dimensional tomographic images to form image data of a three-dimensional image (broadly speaking, an OCT image) of the fundus Ef or the eye to be examined E. Note that the image data of the three-dimensional image means image data in which the positions of pixels are defined by a three-dimensional coordinate system. As the image data of the three-dimensional image, there is image data composed of voxels arranged three-dimensionally. This image data is called volume data or voxel data, etc. When displaying an image based on the volume data, the data processing unit 230 performs rendering processing (such as volume rendering or MIP (Maximum Intensity Projection)) on this volume data to form image data of a pseudo three-dimensional image when viewed from a specific viewing direction. This pseudo three-dimensional image is displayed on a display device such as the display unit 240A.

[0110] In addition, as the image data of the three-dimensional image, it is also possible to form stack data of a plurality of tomographic images. The stack data is image data obtained by three-dimensionally arranging a plurality of tomographic images obtained along a plurality of scanning lines based on the positional relationship of the scanning lines. That is, the stack data is image data obtained by expressing (i.e., embedding in one three-dimensional space) a plurality of tomographic images originally defined by individual two-dimensional coordinate systems by one three-dimensional coordinate system.

[0111] The data processing unit 230 can perform alignment between the fundus image and the OCT image. When the fundus image and the OCT image are acquired in parallel, since the optical systems of both are coaxial, the fundus image and the OCT image acquired (substantially) simultaneously can be aligned with reference to the optical axis of the imaging optical system 30. Also, regardless of the acquisition timing of the fundus image and the OCT image, it is possible to align the OCT image and the fundus image by aligning the image obtained by projecting the OCT image onto the xy plane and the fundus image. This alignment method is applicable even when the optical system for acquiring the fundus image and the optical system for OCT measurement are not coaxial. Also, even when the optical systems of both are not coaxial, if the relative positional relationship between the optical systems of both is known, it is possible to execute alignment similar to the coaxial case with reference to this relative positional relationship.

[0112] As shown in FIG. 4, the data processing unit 230 includes a segmentation processing unit 232 and a correction processing unit 233.

[0113] The segmentation processing unit 232 performs segmentation processing on the OCT image, divides the layer region constituting the tomographic structure in the depth direction, and executes processing for specifying the boundary of the layer region. Here, the OCT image may be the OCT image formed by the image forming unit 220, or the OCT image on which data processing such as luminance correction by the data processing unit 230 has been performed on the OCT image formed by the image forming unit 220. At this time, the segmentation processing unit 232 generates one or more boundary candidate information indicating correction candidates for the boundary of the specified layer region.

[0114] While referring to one or more boundary candidate information, the correction processing unit 233 executes a process of correcting the boundary of the layer region specified by the segmentation process based on the operation information input by the user via the operation unit 240B described later.

[0115] (Segmentation processing unit 232) As shown in FIG. 5, the segmentation processing unit 232 includes an edge detection unit 232A, a boundary candidate specifying unit 232B, and a boundary specifying unit 232C.

[0116] (Edge detection unit 232A) The edge detection unit 232A detects an edge of a luminance value (pixel value) with a high possibility of being the boundary of the layer region in the OCT image (first tomographic image), which is the tomographic image of the eye to be examined E. That is, the edge detection unit 232A detects an edge in the OCT image based on the luminance value (pixel value) of the OCT image. Specifically, the edge detection unit 232A performs edge detection filter processing on the OCT image, emphasizes the edge according to the steepness of the edge, and detects the emphasized edge.

[0117] (Boundary candidate specifying unit 232B) The boundary candidate specifying unit 232B specifies two or more boundary candidates of the layer region such that the cost corresponding to the distance to the edge at each position is maximized or minimized. Specifically, the boundary candidate specifying unit 232B specifies two or more boundary candidates of the layer region such that the cost becomes maximum or minimum as it passes through the edge detected by the edge detection unit 232A.

[0118] In this embodiment, the boundary candidate specifying unit 232B specifies two or more boundary candidates of the layer region such that the above cost (corresponding to the cumulative sum of the costs at each position) is minimized. At this time, the boundary candidate specifying unit 232B specifies the boundary candidates such that the steeper (higher steepness) the edge, the smaller the cost.

[0119] In addition, the boundary candidate specifying unit 232B can specify a boundary candidate determined based on the boundary of the layer region specified in a slice image (B-scan image) different from the OCT image (B-scan image) to be corrected at the boundary of the layer region.

[0120] (Boundary specifying unit 232C) The boundary specifying unit 232C determines a single boundary candidate selected based on cost from among two or more boundary candidates specified by the boundary candidate specifying unit 232B as the boundary of the layer region. Further, the boundary specifying unit 232C specifies information on one or more boundary candidates selected based on cost from among the remaining boundary candidates excluding the boundary adopted as the boundary of the layer region as one or more boundary candidate information.

[0121] Specifically, the boundary specifying unit 232C specifies a first boundary candidate with the maximum or minimum cost as the boundary of the layer region. Further, the boundary specifying unit 232C specifies information on one or more upper boundary candidates when two or more boundary candidates excluding the first boundary candidate are arranged in ascending or descending order based on cost as one or more boundary candidate information. In this embodiment, the boundary specifying unit 232C specifies a first boundary candidate with the minimum cost as the boundary of the layer region. Further, the boundary specifying unit 232C specifies information on one or more upper boundary candidates when two or more boundary candidates excluding the first boundary candidate are arranged in descending order based on cost as one or more boundary candidate information.

[0122] (Correction processing unit 233) The correction processing unit 233 executes a boundary correction process of replacing the boundary of the layer region in the OCT image specified by the segmentation processing unit 232 with the corrected boundary. The corrected boundary is set based on operation information input by a user such as a doctor via the operation unit 240B.

[0123] In some embodiments, the correction processing unit 233 sets, as the corrected boundary of the layer region, the boundary selected from among the boundaries of the layer regions in the OCT image specified by the segmentation processing unit 232 and one or more boundary candidate information based on the operation information input by a user such as a doctor via the operation unit 240B. Further, the correction processing unit 233 can execute a correction process of correcting the boundary of the layer region specified based on the boundary candidate information selected based on the operation information, based on the operation information input by a user such as a doctor via the operation unit 240B.

[0124] The data processing unit 230 that functions as described above is configured to include, for example, the aforementioned processor, RAM, ROM, hard disk drive, circuit board, and the like. A computer program for causing a microprocessor to execute the above functions is stored in advance in a storage device such as a hard disk drive. In some embodiments, the functions of the data processing unit 230 are realized by one or more data processing processors.

[0125] (User Interface 240) As shown in FIG. 3, the user interface 240 includes a display unit 240A and an operation unit 240B. The display unit 240A is configured to include the display device or display apparatus 3 of the arithmetic control unit 200 described above. The operation unit 240B is configured to include the operation device of the arithmetic control unit 200 described above. The operation unit 240B may include various buttons and keys provided on the housing of the ophthalmic device 1 or externally. For example, when 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, and the like provided on this housing. Further, the display unit 240A may include various display devices such as a touch panel provided on the housing of the fundus camera unit 2.

[0126] Note that the display unit 240A and the operation unit 240B do not necessarily need to be configured as separate devices. For example, it is also possible to use a device in which the display function and the operation function are integrated, such as a touch panel. In that case, the operation unit 240B includes the touch panel and a computer program. The operation content for the operation unit 240B is input to the control unit 210 as an electrical signal. Further, operations and information input may be performed using the graphical user interface (GUI) displayed on the display unit 240A and the operation unit 240B.

[0127] The data processing unit 230 (and the image forming unit 220) is an example of the "ophthalmic information processing apparatus" according to the embodiment. The optical system, the image forming unit 220, and the tomographic information image generation unit 231 included in the OCT unit 100, or a communication unit (not shown) is an example of the "acquisition unit" according to the embodiment. The optical system included in the OCT unit 100 is an example of the "optical system" according to the embodiment. The display device 3 or the display unit 240A is an example of the "display means" according to the embodiment.

[0128] By the way, the segmentation process executed by the segmentation processing unit 232 generally depends on the image quality of the image to be processed, and it is often difficult to accurately identify the boundary of the layer region. Therefore, various methods have been proposed to improve the accuracy of the segmentation processing result, but only methods for improving the accuracy in specific diseases or specific cases have been proposed. Therefore, at present, a user such as a doctor needs to check the boundary of the layer region obtained by the segmentation process and correct the boundary of the layer region as necessary.

[0129] FIG. 6A shows an example of the IS / OS boundary identified in the OCT image obtained by raster scan.

[0130] In FIG. 6A, the IS / OS boundary B1 in the OCT image IMG1 is accurately identified by the segmentation process. When an OCT image at a predetermined slice position is formed from the volume data obtained by a three-dimensional OCT scan (3D scan), the change in the shape of the retina is gentle between adjacent slices. However, even in adjacent slice images of the OCT image IMG1 shown in FIG. 6A, the segmentation process may fail to identify the IS / OS boundary.

[0131] FIG. 6B shows an example of the IS / OS boundary identified in an OCT image that is an adjacent slice image of the OCT image in FIG. 6A.

[0132] As shown in FIG. 6B, in the OCT image IMG2, which is an adjacent slice image of the OCT image IMG1, the segmentation process fails to identify the IS / OS boundary (boundary B2).

[0133] Therefore, in this embodiment, as shown in FIG. 6B, boundary candidate information C1 and C2 indicating candidates for correcting the IS / OS boundary B2 are generated by the boundary identification unit 232C, and the generated boundary candidate information C1 and C2 is overlaid and displayed on the OCT image IMG2. Alternatively, the boundary candidate information C1 and C2 may be displayed in parallel with the OCT image IMG2.

[0134] This enables a user such as a doctor to determine whether to correct the boundary of the layer region identified by the segmentation process without much effort, and to easily correct it if correction is necessary.

[0135] Such boundary candidate information is generated based on one or more boundary candidates excluding the boundary identified as the boundary of the layer region among two or more boundary candidates identified by the boundary candidate identification unit 232B as described above.

[0136] The boundary candidate information may further include information indicating a correction candidate for the boundary of the layer region identified as follows.

[0137] (First Example of Boundary Candidate Information) The boundary candidate information may include the boundaries of the layer regions deformed by performing an affine transformation on the boundaries of the layer regions identified by the segmentation process.

[0138] (Second Example of Boundary Candidate Information) The boundary candidate information may be generated from OCT images at slice positions different from the OCT image to be corrected.

[0139] FIGS. 7A to 7C show operation explanatory diagrams of a boundary specifying unit 232C that generates boundary candidate information from OCT images at slice positions different from the OCT image to be corrected.

[0140] FIG. 7A schematically shows an OCT image IMG3 to be corrected and an OCT image IMG4 at a slice position different from that of the OCT image IMG3 in the C-scan direction. The OCT image IMG4 is an adjacent slice image of the OCT image IMG3. The OCT image IMG4 may be a slice image (a slice image with one or more slice positions apart) arranged with one or more slice images placed in the C-scan direction with respect to the OCT image IMG3. The OCT images IMG3 and IMG4 can be generated from volume data obtained by 3D scanning. FIG. 7B shows an example of the OCT image IMG3 in FIG. 7A. FIG. 7C shows an example of the OCT image IMG4 in FIG. 7A.

[0141] As shown in FIG. 7B, it is assumed that the boundary of the layer region identified by the segmentation process for the OCT image IMG3 represents an accurate boundary (success). Also, as shown in FIG. 7C, it is assumed that the boundary of the layer region identified by the segmentation process for the OCT image IMG4 represents an inaccurate boundary (failure).

[0142] At this time, when the boundary specifying unit 232C generates the boundary candidate information of the OCT image IMG4, the boundary specifying unit 232C can generate the boundary of the layer region specified by the OCT image IMG3 as the boundary candidate information.

[0143] That is, when correcting the boundary of the layer region in the OCT image IMG3, the boundary specifying unit 232C generates one or more pieces of boundary candidate information including the boundary of the layer region in the depth direction specified by performing segmentation processing on the OCT image IMG4. Here, the OCT image IMG4 is a slice image adjacent to the OCT image IMG3 in the C-scan direction or a slice image arranged with one or more slice images placed in the C-scan direction with respect to the OCT image IMG3. At this time, the boundary candidate information may include the boundary of the layer region deformed by performing an affine transformation on the boundary of the layer region in the depth direction specified by performing segmentation processing on the OCT image IMG4.

[0144] (Third example of boundary candidate information) Using the result of successful segmentation processing of the slice image in the volume data, the boundary of the same layer region in part or all of the slice images in the volume data may be specified, or boundary candidate information may be generated.

[0145] Fig. 8 schematically shows slice images SIMG1 to SIMGm (m is an integer of 2 or more) in the volume data.

[0146] In Fig. 8, it is assumed that the segmentation processing is successful in the slice image SIMG1. At this time, the boundary specifying unit 232C adopts, as the boundary or boundary candidate information of the same layer region in the slice image IMGm, the boundary of the layer region specified in the slice image SIMG1 or its deformed boundary.

[0147] That is, the boundary specifying unit 232C sets the boundary of the layer region specified by the segmentation process performed on the slice image SIMG1 (the third tomographic image) or its deformed boundary as the boundary of the layer region in the tomographic image (slice image SIMG2) adjacent to the slice image SIMG1 in the C-scan direction. The boundary specifying unit 232C can generate boundary candidate information including the boundary of the layer region obtained by sequentially repeating this two or more times as the boundary candidate information for the slice image SIMGm. The boundary candidate information may include the boundary of the layer region deformed by performing an affine transformation on the boundary of the layer region obtained by sequentially repeating the above process two or more times.

[0148] (Fourth example of boundary candidate information) Using the past segmentation results of the eye E to be examined, boundary candidate information for the same layer region in the OCT image of the eye E to be examined may be generated.

[0149] FIG. 9A schematically shows the segmentation result for the OCT image IMG5 of the eye E to be examined obtained in the past. In FIG. 9A, it is assumed that the segmentation process has been successful.

[0150] FIG. 9B schematically shows the segmentation result for the OCT image IMG6 of the eye E to be examined obtained at a timing different from that of FIG. 9A for the same eye E to be examined. In FIG. 9B, it is assumed that the segmentation process has failed.

[0151] At this time, the boundary specifying unit 232C can generate boundary candidate information including the boundary of the layer region specified in the previously obtained OCT image IMG5 as a correction candidate for the boundary of the layer region of the OCT image IMG6. The boundary candidate information may include the boundary of the layer region deformed by performing an affine transformation on the boundary of the layer region specified in the previously obtained OCT image IMG5.

[0152] (Fifth example of boundary candidate information) A boundary obtained by fitting the boundary of the layer region specified by the segmentation process using a predetermined fitting function may be generated as boundary candidate information.

[0153] That is, the boundary specifying unit 232C can generate one or more pieces of boundary candidate information including the boundary of the layer region obtained by fitting the boundary of the layer region specified by the segmentation process using a predetermined fitting function. The boundary candidate information may include the boundary of the layer region obtained by performing an affine transformation on the boundary of the layer region obtained by fitting using a predetermined fitting function.

[0154] [Operation example] An operation example of the ophthalmic apparatus 1 according to the embodiment will be described.

[0155] FIGS. 10 and 11 show flowcharts of operation examples of the ophthalmic apparatus 1 according to the embodiment. A computer program for realizing the processes shown in FIGS. 10 and 11 is stored in the storage unit 212. The main control unit 211 operates according to this computer program to execute the processes shown in FIGS. 10 and 11.

[0156] (S1: Alignment) First, with a fixation target presented at a predetermined fixation position, the main control unit 211 performs alignment adjustment of the optical system with respect to the eye E to be examined. As an example of the alignment adjustment, there are a case of performing it manually and a case of performing it automatically.

[0157] When the alignment adjustment is performed manually, the main control unit 211 projects a pair of alignment indicators onto the eye E to be examined by the alignment optical system 50. A pair of alignment bright spots are displayed on the display unit 240A as a light-receiving image of these alignment indicators. Further, the main control unit 211 causes the display unit 240A to display an alignment scale representing a position that is a movement target of the pair of alignment bright spots. The alignment scale is, for example, a bracket-shaped image.

[0158] When the positional relationship between the eye E to be examined and the fundus camera unit 2 (objective lens 22) is appropriate, by a known method, a pair of alignment bright spots are each once imaged at a predetermined position (for example, an intermediate position between the corneal apex and the corneal curvature center) and projected onto the eye E to be examined. Here, when the above positional relationship is appropriate, the distance (working distance) between the eye E to be examined and the fundus camera unit 2 is appropriate, and the optical axis of the optical system of the fundus camera unit 2 and the eye axis (corneal apex position) of the eye E to be examined (substantially) coincide. The examiner (user) can perform alignment adjustment of the optical system with respect to the eye E to be examined by three-dimensionally moving the fundus camera unit 2 so as to guide a pair of alignment bright spots into the alignment scale.

[0159] When performing alignment adjustment automatically, a moving mechanism 150 for moving the fundus camera unit 2 is used. The data processing unit 230 identifies the positions of the respective alignment bright spots in the screen displayed on the display unit 240A, and obtains the displacement between the identified positions of the respective alignment bright spots and the alignment scale. The main control unit 211 moves the fundus camera unit 2 by the moving mechanism 150 so as to cancel this displacement. Identification of the positions of the respective alignment bright spots can be executed, for example, by obtaining the luminance distribution of each alignment bright spot and obtaining the centroid position based on this luminance distribution. Since the position of the alignment scale is constant, for example, by obtaining the displacement between its center position and the above centroid position, it is possible to obtain the target displacement. The moving direction and moving distance of the fundus camera unit 2 can be determined with reference to the preset single displacement distances in the x-direction, y-direction, and z-direction (for example, the result of measuring in advance how much the alignment index moves in which direction when the fundus camera unit 2 is moved in which direction by how much). The main control unit 211 generates a signal corresponding to the determined moving direction and moving distance, and transmits this signal to the moving mechanism 150. Thereby, the position of the optical system with respect to the eye E to be examined is automatically adjusted.

[0160] (S2: Set scanning conditions) Next, the main control unit 211 sets scan conditions so as to scan a desired scan area in a desired scan mode.

[0161] For example, the user inputs operation information via the operation unit 240B to specify a scan position (scan area) for OCT scan with respect to a fundus image (front image) of the eye E to be examined that has been previously acquired using the fundus camera unit 2 (imaging optical system 30). As described above, since alignment between the fundus image and the OCT image is not required, OCT scan can be easily performed on the scan position (scan area) specified on the fundus image.

[0162] (S3: OCT Scan) Subsequently, the main control unit 211 controls the optical scanner 42, the OCT unit 100, etc., to execute an OCT scan under the scan conditions set in step S2.

[0163] (S4: Save Scan Data) The main control unit 211 stores the scan data obtained in step S3 in the storage unit 212. The scan data stored in step S4 is three-dimensional scan data.

[0164] (S5: Form OCT Image) Subsequently, the main control unit 211 controls the image forming unit 220 to form a single OCT image (B-scan image), which is a tomographic image at a predetermined slice position, from the scan data stored in step S4.

[0165] (S6: Segmentation Processing) Next, the main control unit 211 controls the segmentation processing unit 232 to perform segmentation processing on the OCT image formed in step S5, identify the boundaries of one or more layer regions, and generate one or more boundary candidate information for the identified boundaries of each layer region.

[0166] Details of step S6 will be described later.

[0167] (S7: Display the boundary of the layer region and boundary candidate information) Subsequently, the main control unit 211 controls the display control unit 211A to cause the display unit 240A to display an OCT image in which the boundary of the desired layer region specified in step S6 and one or more pieces of boundary candidate information are drawn so as to be distinguishable.

[0168] (S8: Correction process) Subsequently, the main control unit 211 controls the correction processing unit 233 to execute a correction process for correcting the boundary of the layer region in the OCT image specified in step S7.

[0169] For example, while referring to one or more pieces of boundary candidate information displayed on the display unit 240A in step S7, the user inputs operation information via the operation unit 240B to correct the boundary of the layer region in the OCT image. The correction processing unit 233 sets the boundary of the layer region corrected based on the operation information as the boundary of the layer region of the OCT image specified in step S6.

[0170] For example, the user selects one of the one or more pieces of boundary candidate information displayed on the display unit 240A in step S7 by inputting operation information via the operation unit 240B. The correction processing unit 233 sets the boundary candidate information selected based on the operation information as the boundary of the layer region of the OCT image specified in step S6.

[0171] For example, the user selects one of the one or more pieces of boundary candidate information displayed on the display unit 240A in step S7 by inputting operation information via the operation unit 240B. The user inputs operation information via the operation unit 240B to correct the boundary specified based on the selected boundary candidate information. The correction processing unit 233 sets the boundary of the layer region corrected based on the operation information as the boundary of the layer region of the OCT image specified in step S6.

[0172] (S9: Saving) Subsequently, the main control unit 211 stores the OCT image with the boundary of the layer region corrected in the correction process in step S8 in the storage unit 212.

[0173] (S10: Next layer region?) Subsequently, the main control unit 211 determines whether there is a boundary of the layer region to be corrected next. For example, the main control unit 211 determines whether there is a boundary of the layer region to be corrected next by determining whether the correction of the boundary of the layer region to be corrected has been completed.

[0174] When it is determined in step S10 that there is a boundary of the layer region to be corrected next (S10: Y), the operation of the ophthalmic device 1 proceeds to step S7. When it is determined in step S10 that there is no boundary of the layer region to be corrected next (S10: N), the operation of the ophthalmic device 1 proceeds to step S11.

[0175] (S11: Next image?) When it is determined in step S10 that there is no boundary of the layer region to be corrected next (S10: N), the main control unit 211 determines whether there is an image for which the boundary of the layer region should be corrected next. For example, the main control unit 211 determines whether there is an image for which the boundary of the layer region should be corrected next by determining whether the correction process has been completed for the OCT images with a predetermined number of slices.

[0176] When it is determined in step S11 that there is an image for which the boundary of the layer region should be corrected next (S11: Y), the operation of the ophthalmic device 1 proceeds to step S5. After proceeding to step S5, steps S5 to S11 are sequentially executed for the OCT image at the next slice position. When it is determined in step S11 that there is no image for which the boundary of the layer region should be corrected next (S11: N), the operation of the ophthalmic device 1 ends (end).

[0177] Step S6 in FIG. 10 is processed according to the flow shown in FIG. 11.

[0178] (S21: Identify the endpoints of each layer region of the OCT image) The segmentation processing unit 232 identifies the endpoints of each of two or more pre-determined layer regions.

[0179] For example, the segmentation processing unit 232 identifies the endpoints based on the pixel values at the left end, right end, upper end, and lower end of the OCT image. At this time, the segmentation processing unit 232 first identifies the endpoints of a predetermined layer region with a higher luminance value than other layer regions such as the ILM and RPE, and then identifies the endpoints of the remaining layer regions. Thereby, by defining the layer regions in order from the layer regions that are easier to detect, the identification accuracy of the layer regions can be improved.

[0180] (S22: Specify boundary candidates based on cost) Subsequently, the edge detection unit 232A performs edge detection filter processing on the OCT image and detects edges emphasized according to the steepness of the edges. The steeper the edge, the larger the pixel value at the pixel position after the edge detection filter processing. For example, the reciprocal of this pixel value is used for cost calculation. For example, the boundary candidate specifying unit 232B traces the boundary of the layer region starting from the endpoints specified in step S21, and specifies two or more boundary candidates of the layer region so that the cumulative sum of the above costs becomes the minimum.

[0181] In step S22, the same processing is repeated for each layer region, and two or more boundary candidates are specified for each layer region.

[0182] (S23: Specify the boundary of the layer region) Next, the boundary specifying unit 232C specifies, as the boundary (adopted line, adopted region) of the layer region, the boundary candidate with the minimum cost among the two or more boundary candidates specified in step S22.

[0183] (S24: Generate boundary candidate information) Subsequently, the boundary specifying unit 232C generates information representing one or more upper boundary candidates when arranging two or more boundary candidates excluding the boundary (boundary candidate with the minimum cost) specified in step S23 in descending order based on cost as one or more boundary candidate information.

[0184] (S25: Is there another slice image?) Subsequently, the segmentation processing unit 232 determines whether there is another slice image at another slice position in the C-scan direction, other than the OCT image to be corrected, and for which the segmentation processing has been successful for the layer region.

[0185] When it is determined in step S25 that there is the above-mentioned other slice image (S25: Y), the process of step S6 in FIG. 10 proceeds to step S26. When it is determined in step S25 that there is no such other slice image (S25: N), the process of step S6 in FIG. 10 proceeds to step S27.

[0186] (S26: Add boundary candidate information) When it is determined in step S25 that there is the above-mentioned other slice image (S25: Y), the boundary identification unit 232C generates boundary candidate information including the boundary of the layer region in the depth direction identified by performing segmentation processing on the above-mentioned other slice image as shown in FIGS. 7A to 7C or the boundary whose boundary has been deformed by affine transformation. The boundary identification unit 232C adds the generated boundary candidate information to the boundary candidate information generated in step S24 (or the generated boundary candidate information may replace a part of the boundary candidate information generated in step S24).

[0187] (S27: Is there past data?) When it is determined in step S25 that there is no such other slice image (S25: N), or subsequent to step S26, the segmentation processing unit 232 determines whether there is an OCT image acquired in the past for the same eye to be examined and for which the segmentation processing has been successful for the layer region.

[0188] When it is determined in step S27 that there is the above OCT image (S27: Y), the process of step S6 in FIG. 10 proceeds to step S28. When it is determined in step S27 that there is no such OCT image (S27: N), the process of step S6 in FIG. 10 ends (ends).

[0189] (S28: Add boundary candidate information) When it is determined in step S27 that there is the above other OCT image (S27: Y), the boundary specifying unit 232C generates boundary candidate information including the boundary of the depth direction layer region specified by performing segmentation processing on the above OCT image or the boundary obtained by deforming the boundary by affine transformation as shown in FIGS. 9A and 9B. The boundary specifying unit 232C adds the generated boundary candidate information to the boundary candidate information generated in step S24 or step S26 (or the generated boundary candidate information may replace a part of the boundary candidate information generated in step S24 or step S26).

[0190] Following step S28, the process of step S6 in FIG. 10 ends (ends).

[0191] To the boundary candidate information generated in the flow shown in FIG. 11, the boundary of the layer region deformed by performing an affine transformation on the boundary of the layer region specified in step S23 may be further added.

[0192] Further, to the boundary candidate information, the boundary of the layer region obtained by using the result of successful segmentation processing of the slice image in the volume data may be added.

[0193] FIG. 12 shows a flowchart of an operation example of the segmentation processing unit 232. The storage unit 212 stores a computer program for realizing the processing shown in FIG. 12. The segmentation processing unit 232 operates according to this computer program to execute the processing shown in FIG. 12.

[0194] (S31: Select a reference slice image) First, the segmentation processing unit 232 selects, as a reference slice image, one slice image out of a plurality of slice images at a plurality of slice positions in the volume data for a predetermined layer region.

[0195] For example, the segmentation processing unit 232 selects a reference slice image based on operation information input by a user such as a doctor via the operation unit 240B. The reference slice image is an image in which the boundary of a predetermined layer region has been successfully identified by previously executed segmentation processing.

[0196] For example, when the layer region to be processed is a layer region where the boundary of a layer region such as ILM or RPE is easily detected, the segmentation processing unit 232 selects a reference slice image at a slice position corresponding to a site in the volume data where the layer region is particularly easily detected.

[0197] (S32: Reflect on the boundary of the layer region of the adjacent slice image) Subsequently, the segmentation processing unit 232 reflects the boundary of the layer region identified in the reference slice image selected in step S31 on the boundary of the layer region of the adjacent slice image of the reference slice image. The segmentation processing unit 232 sets, as the boundary of the layer region in the adjacent slice image, the boundary of the layer region identified in the reference slice image for the layer region to be processed. In some embodiments, the segmentation processing unit 232 sets, as the boundary of the layer region in the adjacent slice image, the boundary deformed by performing an affine transformation on the boundary of the layer region identified in the reference slice image.

[0198] (S33: Next slice image? Next, the segmentation processing unit 232 determines whether there is a slice image that should reflect the boundary of the next layer region. For example, the segmentation processing unit 232 determines whether there is a slice image that should reflect the boundary of the next layer region by determining whether the processing for the slice images at all slice positions in the volume data has been completed.

[0199] When it is determined in step S33 that there is a slice image that should reflect the boundary of the next layer region (S33: Y), the processing of the segmentation processing unit 232 proceeds to step S32. After the transition to step S32, the same processing as above is executed for the next slice image.

[0200] When it is determined in step S33 that there is no slice image that should reflect the boundary of the next layer region (S33: N), the processing of the segmentation processing unit 232 ends (end).

[0201] The segmentation processing unit 232 can execute the processing of FIG. 12 for each layer region. For example, in the boundary candidate information, the boundary of the layer region reflected in the slice image at the same slice position as the OCT image to be processed among two or more slice images obtained by the processing of FIG. 12 may be added.

[0202] Furthermore, in the boundary candidate information, a boundary obtained by fitting the boundary of the layer region specified by the segmentation processing using a predetermined fitting function may be added.

[0203] Note that the boundary candidate information does not necessarily include all of the above boundary candidate information, and may include at least one of the above boundary candidate information.

[0204] As described above, according to the embodiment, by performing segmentation processing on the OCT image, the boundary of the layer region specified thereby and one or more boundary candidate information indicating candidates for correcting this boundary are displayed on the display means in an identifiable manner. Thus, while referring to the one or more boundary candidate information, it becomes possible to observe the position of the boundary specified by the segmentation processing or correct the above boundary. As a result, while reducing the labor, it becomes possible to specify the layer region in the tomographic structure of the eye to be examined with high accuracy.

[0205] <Modification Example> The boundary candidate information according to the embodiment is not limited to the boundary candidate information described above. For example, the boundary candidate information may include the boundary of the layer region specified by performing segmentation processing on a tomographic information image representing tomographic information of the eye to be examined, which is generated by a method different from the OCT image (or a boundary deformed by affine-transforming the boundary).

[0206] Examples of the tomographic information image include an OCT angiography (OCTA) image, an attenuation coefficient image, a polarization information image, a birefringence image, a superimposed image of the above images, and the like. When any one of the OCTA image, the attenuation coefficient image, the polarization information image, and the birefringence image is used as a reference image, the superimposed image is an image obtained by superimposing one or more images excluding the above reference image among the OCTA image, the attenuation coefficient image, the polarization information image, and the birefringence image on the reference image. Since the tomographic information image is generated by a method different from the OCT image, it is tomographic information in which the distribution of characteristics of physical quantities different from the reflection intensity at each position of the tomographic structure based on the backscattered light of the measurement light of OCT is imaged. Thereby, there is a possibility that the boundary of the layer region that is not clearly depicted in the OCT image is clearly depicted in the tomographic information image.

[0207] In particular, when an OCT image and a tomographic information image are generated by an OCT scan, or when the tomographic information image is generated based on the OCT image, registration (alignment) between the OCT image and the tomographic information image becomes unnecessary. Thereby, the position in one of the OCT image and the tomographic information image can be easily specified from the position in the other image.

[0208] Note that although it may be configured to acquire a tomographic information image from outside the ophthalmic apparatus 1, in a modification of the embodiment, a case where an OCT image and a tomographic information image are generated by an OCT scan will be described.

[0209] Hereinafter, a modification of the embodiment will be described mainly focusing on the differences from the embodiment.

[0210] The difference in the configuration of the optical system of the ophthalmic apparatus according to this modification from the configuration of the optical system of the ophthalmic apparatus according to the embodiment is mainly that an OCT unit 100a is provided instead of the OCT unit 100.

[0211] FIG. 13 shows a configuration example of the optical system of the OCT unit 100a according to this modification. In FIG. 13, the same parts as those in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0212] The difference in the configuration of the OCT unit 100a shown in FIG. 13 from the configuration of the OCT unit 100 shown in FIG. 2 is mainly that an incident polarization control unit 130 is provided between the fiber coupler 105 and the collimating lens unit 40, and a polarization separation unit 140 is provided instead of the fiber coupler 122.

[0213] The measurement light LS generated by the fiber coupler 105 is guided to the incident polarization control unit 130 by the optical fiber 128. The incident polarization control unit 130 generates two measurement lights LS in polarization states whose polarization directions are orthogonal to each other from the incident measurement light LS, or generates a measurement light LS in which the two generated polarization states are superimposed. The measurement lights LS in the two polarization states are the measurement light of x polarization (the first polarization state) and the measurement light of y polarization (the second polarization state). The measurement light LS emitted from the incident polarization control unit 130 is guided to the collimating lens unit 40 by the optical fiber 131.

[0214] The backscattered light of the measurement light LS by the fundus Ef travels in the reverse direction along the same path as the forward path and is guided to the fiber coupler 105, and reaches the polarization separation unit 140 via the optical fiber 128.

[0215] The reference light LR whose light amount is adjusted by the attenuator 120 is guided to the polarization separation unit 140 by the optical fiber 121.

[0216] The polarization separation unit 140 separates the measurement light LS (return light) incident via the optical fiber 128 into two measurement lights LS (return lights) in polarization states whose polarization directions are orthogonal to each other. The two measurement lights LS (return lights) in the polarization states are the measurement light (return light) of x polarization and the measurement light (return light) of y polarization. Then, the polarization separation unit 140 synthesizes (interferes) the measurement light LS and the reference light LR passing through the optical fiber 121 for each polarization state to generate interference lights in two polarization states, or generates an interference light in which the two generated polarization states are superimposed. In some embodiments, the polarization separation unit 140 is configured to separate the reference light LR into two reference lights LR in polarization states whose polarization directions are orthogonal to each other, and then generate an interference light between the return light of the measurement light LS of x polarization and the reference light LR of x polarization, and generate an interference light between the return light of the measurement light LS of y polarization and the reference light LR of y polarization.

[0217] The polarization separation unit 140 generates a pair of interference light LCs for each polarization state or a pair of interference light LCs in which two polarization states are superimposed by branching the interference light at a predetermined branching ratio (for example, 50:50). The pair of interference light LCs emitted from the polarization separation unit 140 is guided to the detector 125 via the light guide member 141.

[0218] In this modification example, using this optical system, it is possible to acquire at least one of an OCT image, an OCTA image, an attenuation coefficient image, a DOPU (Degree Of Polarization Uniformity) image as a polarization information image, and a birefringence image as a tomographic information image.

[0219] The OCT image can be generated, for example, based on the detection results of a pair of interference light LCs in which two polarization states are superimposed obtained by the detector 125 when a pair of interference light LCs in which two polarization states are superimposed is emitted from the polarization separation unit 140. Alternatively, the OCT image can be generated, for example, based on a synthesis result obtained by further synthesizing the detection results of the interference light LCs of two polarization states obtained by the detector 125 when a pair of interference light for each polarization state synthesized from the polarization separation unit 140 is emitted. At this time, by controlling the incident polarization control unit 130, it is possible to configure to generate the measurement light LS in which two polarization states are superimposed.

[0220] The OCTA image can be generated, for example, using a plurality of OCT images acquired in the same manner as above by repeatedly performing OCT scanning at the same location. Alternatively, the OCTA image can be generated, for example, using the detection results of a plurality of time series of a pair of interference light LCs in which two polarization states are superimposed obtained in the same manner as above by repeatedly performing OCT scanning at the same location. The position of the part depicted in such an OCTA image is determined based on one OCT image used for generation. Therefore, registration processing between the OCTA image and the OCT image is not required.

[0221] The attenuation coefficient image can be generated using, for example, an OCT image as described later. Therefore, registration processing between the attenuation coefficient image and the OCT image is unnecessary.

[0222] The DOPU image can be generated, for example, based on the detection results of the interference light of two polarization states obtained by the detector 125 by emitting the interference light of two polarization states synthesized for each polarization state from the polarization separation unit 140. At this time, by controlling the incident polarization control unit 130, it is possible to configure the measurement light LS in which two polarization states are superimposed to be generated.

[0223] The birefringence image can be generated, for example, based on the detection results of a pair of interference lights LC of each of the two polarization states obtained by the detector 125 by emitting the measurement light LS of two polarization states from the incident polarization control unit 130 and emitting the interference light of two polarization states synthesized for each polarization state from the polarization separation unit 140.

[0224] As described above, by configuring to emit the measurement light LS of two polarization states from the incident polarization control unit 130, emit the interference light of two polarization states synthesized for each polarization state from the polarization separation unit 140, and detect the interference light of two polarization states obtained by the detector 125, it is possible to acquire an OCT image (tomographic image), a DOPU image, and a birefringence image by a single OCT scan. Therefore, registration processing between the OCT image, the DOPU image, and the birefringence image can be made unnecessary. Also, as described above, since the registration processing between the OCTA image and the OCT image can be made unnecessary, the registration processing between the OCT image, the OCTA image, the DOPU image, and the birefringence image can be made unnecessary.

[0225] The difference between the configuration of the processing system of the ophthalmic device according to this modification example and the configuration of the processing system of the ophthalmic device according to the embodiment is mainly that the main control unit 211 controls the incident polarization control unit 130 and the polarization separation unit 140, and that a data processing unit 230a is provided instead of the data processing unit 230.

[0226] FIG. 14 shows a block diagram of a configuration example of the data processing unit 230a according to this modified example. In FIG. 14, the same parts as those in FIG. 4 are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0227] The difference in the configuration of the data processing unit 230a from the configuration of the data processing unit 230 is that a tomographic information image generation unit 231 is added to the data processing unit 230. The tomographic information image generation unit 231 generates a tomographic information image from the detection result of the interference light LC or the OCT image. Here, the OCT image may be an OCT image formed by the image forming unit 220, or an OCT image obtained by performing data processing such as luminance correction on the OCT image formed by the image forming unit 220 by the data processing unit 230a.

[0228] FIG. 15 shows a block diagram of a configuration example of the tomographic information image generation unit 231 in FIG. 14.

[0229] The tomographic information image generation unit 231 includes an OCTA image generation unit 231A, an attenuation coefficient image generation unit 231B, a DOPU image generation unit 231C, and a birefringence image generation unit 231D.

[0230] (OCTA Image Generation Unit 231A) The OCTA image generation unit 231A generates an OCTA image based on the detection result of the interference light or the OCT image formed based on the detection result of the interference light. The OCTA image is a motion contrast image representing the distribution of the contrast intensity that changes due to the motion at each pixel position. The OCTA image is a blood vessel-enhanced image or an angiogram in which retinal blood vessels and choroidal blood vessels are emphasized. In the OCTA image representing the tomographic information of the fundus Ef, in particular, the boundaries of the ILM, INL, OPL, and RPE are emphasized and depicted as compared with the OCT image (tomographic image) formed by the image forming unit 220.

[0231] The OCTA image generation unit 231A generates an OCTA image as a motion contrast image by repeatedly performing OCT scans on substantially the same cross-section in the eye E to be examined. That is, the OCTA image generation unit 231A generates an OCTA image based on scan data collected in time series by OCT scans at substantially the same scan position in the eye E to be examined.

[0232] For example, the OCTA image generation unit 231A compares two OCT images or scan data obtained by repeatedly performing OCT scans on substantially the same part of the eye E to be examined. The OCTA image generation unit 231A generates an OCTA image, which is an enhanced image in which the changed part is emphasized, by converting the pixel value of the changed part of the signal intensity obtained by comparing the two OCT images or scan data into a pixel value corresponding to the change amount.

[0233] In some embodiments, the OCTA image generation unit 231A can extract information for a predetermined thickness at a desired part from a plurality of generated OCTA images and construct it as an en-face image.

[0234] (Attenuation coefficient image generation unit 231B) The attenuation coefficient image generation unit 231B generates an attenuation coefficient image based on the detection result of the interference light or an OCT image formed based on the detection result of the interference light. The power of the measurement light LS as coherent light is attenuated by scattering and absorption during propagation through the medium. The attenuation coefficient image is an image representing the distribution of the attenuation coefficient of the irradiance of the measurement light LS that depends on the optical characteristics of the medium, as the distribution of the irradiance of the measurement light LS. As an example of the attenuation coefficient, there is an attenuation coefficient when representing the irradiance that attenuates in the depth direction according to Lambert-Beer's Law with respect to the irradiance of the incident light beam at the reference position in the depth direction. Such a distribution of the attenuation coefficient is considered useful for acquiring information on the composition of the medium. In the attenuation coefficient image representing the tomographic information of the fundus Ef, the boundaries of the ILM, EZ, RPE, and CSI are particularly emphasized and depicted as compared with the OCT image (tomographic image) formed by the image formation unit 220.

[0235] The attenuation coefficient image generation unit 231B generates an attenuation coefficient image, for example, by replacing the pixel value (luminance value) at each pixel position of the OCT image with a pixel value corresponding to the attenuation coefficient generated based on the pixel value of the OCT image.

[0236] FIG. 16 shows an operation explanatory diagram of the attenuation coefficient image generation unit 231B. FIG. 16 schematically shows the operation of the attenuation coefficient image generation unit 231B when calculating the pixel value of the pixel P1 of the attenuation coefficient image IMG11 corresponding to the pixel P in the OCT image IMG10.

[0237] Assuming that the pixel of interest in the OCT image IMG10 is the pixel P, the attenuation coefficient image generation unit 231B first identifies the pixel values of one or more pixels in the A-scan direction (depth direction) passing through the pixel P for the OCT image IMG10. Next, the attenuation coefficient image generation unit 231B obtains, as the pixel value of the pixel P1 of the attenuation coefficient image IMG11, a value obtained by dividing the pixel value of the pixel P by the cumulative sum of the pixel values of one or more pixels located deeper than the pixel P in the OCT image IMG10.

[0238] For example, as described in "Depth-resolved model-based reconstruction of attenuation coefficients in optical coherence tomography" (K.A. Vermeer et.al, January 1, 2014, Vol.5, No.1, DOI:10.1364 / BOE.5.000322, BIOMEDICAL OPTICS EXPRESS, pp.322-337), the attenuation coefficient image generation unit 231B obtains the pixel value Ia(i) of the pixel P1 at the depth position "i" of the attenuation coefficient image IMG11 corresponding to the pixel P at the depth position "i" of the OCT image IMG10 according to Equation (1).

[0239] [Number]

[0240] In Equation (1), "Δ" represents the pixel size in the depth direction, "i" represents the depth position, and "I[i]" represents the pixel value (luminance value) of the OCT image IMG10 at the depth position "i".

[0241] In some embodiments, the attenuation coefficient image generation unit 231B performs correction on the pixel value Ia(i) obtained by Equation (1) considering light absorption, multiple scattering, and diffusion.

[0242] The attenuation coefficient image generation unit 231B generates the attenuation coefficient image IMG11 by repeating the above process for each pixel of the OCT image IMG10.

[0243] (DOPU Image Generation Unit 231C) As described above, the DOPU image generation unit 231C generates a DOPU image based on the detection result of interference light obtained by emitting interference light of two polarization states synthesized for each polarization state from the polarization separation unit 140. The DOPU image is an image representing the distribution of the polarization uniformity of the measurement light propagating through the medium. In the DOPU image representing the tomographic information of the fundus Ef, the boundaries of the RPE, choroid, and CSI are particularly emphasized and depicted as compared with the OCT image (tomographic image) formed by the image formation unit 220.

[0244] For example, as described in "Degree of polarization uniformity with high noise immunity using polarization-sensitive optical coherence tomography" (S. Makita et.al, December 15, 2014, Vol.39, No.24, OPTICS LETTERS, pp.6783-6786), the DOPU image generation unit 231C generates a DOPU image by obtaining the pixel value of each pixel of the DOPU image based on the detection result of the interference light detected for each polarization state.

[0245] In some embodiments, the DOPU image generation unit 231C generates a DOPU image by obtaining the pixel value of each pixel of the DOPU image using the pixel values of the OCT images formed for each polarization state by the image formation unit 220.

[0246] (Birefringence image generation unit 231D) As described above, the birefringence image generation unit 231D generates a birefringence image based on the detection result of interference light obtained by emitting the measurement light LS in which two polarization states are superimposed from the incident polarization control unit 130 and emitting the interference light of two polarization states synthesized for each polarization state from the polarization separation unit 140. The birefringence image is an image representing the distribution of the birefringence of the measurement light propagating through the medium. In the birefringence image representing the tomographic information of the fundus Ef, the boundaries of the ILM and RPE are particularly emphasized and depicted as compared with the OCT image (tomographic image) formed by the image formation unit 220.

[0247] For example, as described in "Birefringence imaging of posterior eye by multi-functional Jones matrix optical coherence tomography" (S. Sugiyama et.al, December 1, 2015, Vol.6, No.12, DOI:10.1364 / BOE.6.004951, BIOMEDICAL OPTICS EXPRESS, pp.4951-4974), the birefringence image generation unit 231D generates a birefringence image by obtaining the pixel value of each pixel of the birefringence image based on the detection result of the interference light detected for each polarization state.

[0248] In some embodiments, the birefringence image generation unit 231D generates a birefringence image by obtaining the pixel value of each pixel of the birefringence image using the pixel values of the OCT images formed for each polarization state by the image formation unit 220.

[0249] In addition, the tomographic information image generation unit 231 can generate a superimposed image of one or more of the OCTA image, the attenuation coefficient image, the DOPU image, and the birefringence image. When any one of the OCTA image, the attenuation coefficient image, the DOPU image, and the birefringence image is used as a reference image, the superimposed image is an image obtained by superimposing one or more images excluding the above reference image on the reference image among the OCTA image, the attenuation coefficient image, the DOPU image, and the birefringence image.

[0250] The segmentation processing unit 232 can perform segmentation processing on at least one of the OCTA image, the attenuation coefficient image, the DOPU image, the birefringence image, and the superimposed image generated by the tomographic information image generation unit 231.

[0251] In this modification example, the boundary candidate information includes at least one of the boundaries of the layer regions specified by the segmentation processing for the OCTA image, the attenuation coefficient image, the DOPU image, the birefringence image, and the superimposed image.

[0252] FIG. 17 schematically shows an example in which the segmentation result for the OCT image IMG12 and the segmentation result for the attenuation coefficient image are superimposed and displayed on the OCT image IMG12 to be processed.

[0253] The segmentation processing unit 232 identifies the boundary B10 of the CSI by performing segmentation processing on the OCT image IMG12, and identifies the boundary B11 of the CSI by performing segmentation processing on the attenuation coefficient image. The display control unit 211A causes the display unit 240A to display an OCT image in which the boundary B10 and the boundary B11 are superimposed on the OCT image IMG12. At this time, the attenuation coefficient image may be superimposed on the OCT image IMG12 and displayed.

[0254] The OCTA image, the DOPU image, and the birefringence image are examples of the "tomographic information image" according to the embodiment. The DOPU image is an example of the "polarization information image" according to the embodiment.

[0255] As described above, according to this modification example, as boundary candidate information, the boundary of the layer region specified by performing segmentation processing on the tomographic information image in which a layer structure different from the layer structure depicted in the OCT image is emphasized and depicted is displayed. Therefore, it becomes possible to accurately determine whether or not the boundary needs to be corrected by observing in detail the boundary of the layer region specified in the OCT image.

[0256] [Operation] An ophthalmic information processing apparatus, an ophthalmic apparatus, an ophthalmic information processing method, and a program according to the embodiment will be described.

[0257] The first aspect of the embodiment is an ophthalmic information processing apparatus (data processing unit 230 (and image forming unit 220)) including an acquisition unit (an optical system included in the OCT unit 100, an image forming unit 220, and a tomographic information image generation unit 231, or a communication unit not shown), a segmentation processing unit (232), and a display control unit (211A). The acquisition unit acquires image data of a first tomographic image obtained by performing optical coherence tomography on an eye to be examined (E). The segmentation processing unit identifies the boundary of the layer region in the depth direction by performing segmentation processing on the first tomographic image based on the image data. The display control unit causes a display means (display device 3, display unit 240A) to display the boundary of the layer region identified by the segmentation processing unit and one or more boundary candidate information indicating candidates for modifying the boundary in a distinguishable manner.

[0258] According to such an aspect, the boundary of the layer region identified by performing segmentation processing on the first tomographic image (OCT image) and one or more boundary candidate information indicating candidates for modifying this boundary are displayed on the display means in a distinguishable manner. Thereby, while referring to the one or more boundary candidate information, it becomes possible to observe the position of the boundary identified by the segmentation processing or to correct the above boundary. As a result, while reducing the labor, it becomes possible to accurately identify the layer region in the tomographic structure of the eye to be examined.

[0259] In the second aspect of the embodiment, in the first aspect, the display control unit causes the display means to display the boundary of the layer region and one or more boundary candidate information in an overlapping manner.

[0260] According to such an aspect, since the positional relationship between the boundary of the layer region identified by the segmentation processing and the one or more boundary candidate information can be easily grasped, it becomes possible to easily determine whether it is necessary to correct the boundary identified by the segmentation processing.

[0261] In the third aspect of the embodiment, in the first aspect or the second aspect, the display control unit causes the display means to display each of the boundary of the layer region and the one or more boundary candidate information in a different manner.

[0262] According to such an aspect, since the positional relationship between the boundary of the layer region specified by the segmentation process and one or more boundary candidate information can be easily grasped, it becomes possible to easily determine whether or not the boundary specified by the segmentation process needs to be corrected.

[0263] A fourth aspect of the embodiment includes, in any one of the first to third aspects, an operation unit (240B) and a correction processing unit (233) that corrects the boundary of the layer region based on boundary candidate information specified based on the user's operation information for the operation unit from among one or more boundary candidate information.

[0264] According to such an aspect, since the boundary of the layer region can be corrected based on the boundary candidate information specified by the user using the operation unit, it becomes possible to accurately identify the layer region in the tomographic structure of the eye to be examined while reducing the labor.

[0265] In a fifth aspect of the embodiment, in any one of the first to fourth aspects, one or more boundary candidate information includes boundaries of depth-direction layer regions specified by performing segmentation processing on a slice image adjacent to the first tomographic image in the C-scan direction or a second tomographic image that is a slice image arranged by placing one or more slice images in the C-scan direction with respect to the first tomographic image.

[0266] According to such an aspect, since the boundary of the layer region in the first tomographic image can be observed in detail using the boundary of the layer region specified in the second tomographic image, it becomes possible to accurately identify the layer region in the tomographic structure of the eye to be examined while reducing the labor.

[0267] In a sixth aspect of the embodiment, in any one of the first to fifth aspects, one or more boundary candidate information includes boundaries of depth-direction layer regions specified by performing segmentation processing on a second tomographic image of the eye to be examined acquired in the past.

[0268] According to such an aspect, since the boundary of the layer region in the first tomographic image can be observed in detail using the boundary of the layer region specified in the second tomographic image of the eye to be examined acquired in the past, it becomes possible to accurately specify the layer region in the tomographic structure of the eye to be examined while reducing the labor.

[0269] In the seventh aspect of the embodiment, in any of the first to sixth aspects, one or more pieces of boundary candidate information include the boundary of the layer region obtained by fitting the boundary of the layer region specified by the segmentation process using a predetermined fitting function.

[0270] According to such an aspect, since the boundary of the layer region in the first tomographic image can be observed in detail using the boundary of the layer region obtained by fitting the boundary of the layer region specified in the first tomographic image using a predetermined fitting function, it becomes possible to accurately specify the layer region in the tomographic structure of the eye to be examined while reducing the labor.

[0271] In the eighth aspect of the embodiment, in any of the first to seventh aspects, one or more pieces of boundary candidate information include the boundary of the layer region obtained by sequentially repeating two or more times the setting of the boundary of the layer region specified by the segmentation process performed on a third tomographic image different from the first tomographic image as the boundary of the layer region in the tomographic image adjacent to the third tomographic image in the C-scan direction.

[0272] According to such an aspect, since the boundary of the layer region in the first tomographic image can be observed in detail using the boundary of the layer region specified by the segmentation process performed on a third tomographic image different from the first tomographic image, it becomes possible to accurately specify the layer region in the tomographic structure of the eye to be examined while reducing the labor.

[0273] In the ninth aspect of the embodiment, in any of the first to eighth aspects, one or more boundary candidate information includes boundaries of layer regions specified by segmentation processing, slice images adjacent to the first tomographic image in the C-scan direction, or slice images arranged with one or more slice images placed in the C-scan direction with respect to the first tomographic image. It includes boundaries of layer regions in the depth direction specified by performing segmentation processing on the second tomographic image, boundaries of layer regions obtained by fitting the boundaries of layer regions specified by segmentation processing using a predetermined fitting function, and boundaries of layer regions specified by segmentation processing performed on a third tomographic image different from the first tomographic image. It includes boundaries of layer regions obtained by performing an affine transformation on at least one of the boundaries of layer regions obtained by sequentially repeating two or more times the setting of the boundary of the layer region in the tomographic image adjacent to the third tomographic image in the C-scan direction as the boundary of the layer region.

[0274] According to such an aspect, since the boundary of the layer region in the first tomographic image can be observed in detail using the boundary obtained by performing an affine transformation, it becomes possible to accurately identify the layer region in the tomographic structure of the eye to be examined while reducing the labor.

[0275] In the tenth aspect of the embodiment, in any of the first to ninth aspects, the segmentation processing unit includes an edge detection unit, a boundary candidate specifying unit, and a boundary specifying unit. The edge detection unit detects edges in the first tomographic image based on the luminance values of the first tomographic image. The boundary candidate specifying unit specifies two or more boundary candidates of the layer region such that the cost becomes maximum or minimum as it passes through the edge. The boundary specifying unit specifies the first boundary candidate with the maximum or minimum cost as the boundary of the layer region, and specifies information representing one or more upper boundary candidates when two or more boundary candidates excluding the first boundary candidate are arranged in ascending or descending order based on the cost as one or more boundary candidate information.

[0276] According to such an aspect, edges in the first tomographic image are detected based on the luminance values of the first tomographic image, and the boundary of the layer region of the first tomographic image and one or more boundary candidate information are specified based on the cost that becomes maximum or minimum as it passes through the detected edges. Therefore, while reducing the labor, it becomes possible to specify the layer region in the tomographic structure of the eye to be examined with high accuracy.

[0277] The eleventh aspect of the embodiment is an ophthalmic device (1) including an optical system (OCT units 100, 100a) that performs optical coherence tomography on an eye to be examined, an image forming unit (220) that forms a first tomographic image based on a detection result of interference light obtained by the optical system, and an ophthalmic information processing device according to any one of the first aspect to the tenth aspect.

[0278] According to such an aspect, it becomes possible to provide an ophthalmic device capable of observing the position of the boundary specified by the segmentation process and correcting the above boundary while referring to one or more boundary candidate information.

[0279] The twelfth aspect of the embodiment is an ophthalmic information processing method including an acquisition step, a segmentation process step, and a display control step. The acquisition step acquires image data of a first tomographic image obtained by performing optical coherence tomography on an eye to be examined (E). The segmentation process step specifies the boundary of the layer region in the depth direction by performing a segmentation process on the first tomographic image based on the image data. The display control step causes a display means (display device 3, display unit 240A) to display the boundary of the layer region specified in the segmentation process step and one or more boundary candidate information indicating candidates for correcting the boundary in a distinguishable manner.

[0280] According to such an aspect, the boundary of the layer region identified by performing segmentation processing on the first tomographic image (OCT image) and one or more boundary candidate information indicating candidates for modifying this boundary are displayed on the display means so as to be distinguishable. Thereby, while referring to the one or more boundary candidate information, it becomes possible to observe the position of the boundary identified by the segmentation processing and to modify the above-mentioned boundary. As a result, while reducing the labor, it becomes possible to accurately identify the layer region in the tomographic structure of the eye to be examined.

[0281] In the 13th aspect of the embodiment, in the 12th aspect, the display control step causes the display means to display the boundary of the layer region and the one or more boundary candidate information in an overlapping manner.

[0282] According to such an aspect, since the positional relationship between the boundary of the layer region identified by the segmentation processing and the one or more boundary candidate information can be easily grasped, it becomes possible to easily determine whether or not it is necessary to correct the boundary identified by the segmentation processing.

[0283] In the 14th aspect of the embodiment, in the 12th aspect or the 13th aspect, the display control step causes the display means to display each of the boundary of the layer region and the one or more boundary candidate information in different manners.

[0284] According to such an aspect, since the positional relationship between the boundary of the layer region identified by the segmentation processing and the one or more boundary candidate information can be easily grasped, it becomes possible to easily determine whether or not it is necessary to correct the boundary identified by the segmentation processing.

[0285] In the 15th aspect of the embodiment, in any one of the 12th aspect to the 14th aspect, a correction processing step of correcting the boundary of the layer region is included based on the boundary candidate information specified based on the user's operation information for the operation unit (240B) from among the one or more boundary candidate information.

[0286] According to such an aspect, since the boundary of the layer region can be corrected based on the boundary candidate information specified by the user using the operation unit, it becomes possible to accurately identify the layer region in the tomographic structure of the eye to be examined while reducing the labor.

[0287] In the 16th aspect of the embodiment, in any of the 12th to 15th aspects, one or more pieces of boundary candidate information include the boundary of the depth-direction layer region specified by performing segmentation processing on a slice image adjacent to the first tomographic image in the C-scan direction or a second tomographic image that is a slice image arranged with one or more slice images placed in the C-scan direction with respect to the first tomographic image.

[0288] According to such an aspect, since the boundary of the layer region in the first tomographic image can be observed in detail using the boundary of the layer region specified in the second tomographic image, it becomes possible to accurately identify the layer region in the tomographic structure of the eye to be examined while reducing the labor.

[0289] In the 17th aspect of the embodiment, in any of the 12th to 16th aspects, one or more pieces of boundary candidate information include the boundary of the depth-direction layer region specified by performing segmentation processing on a second tomographic image of the eye to be examined acquired in the past.

[0290] According to such an aspect, since the boundary of the layer region in the first tomographic image can be observed in detail using the boundary of the layer region specified in the second tomographic image of the eye to be examined acquired in the past, it becomes possible to accurately identify the layer region in the tomographic structure of the eye to be examined while reducing the labor.

[0291] In the 18th aspect of the embodiment, in any of the 12th to 17th aspects, one or more pieces of boundary candidate information include the boundary of the layer region obtained by fitting the boundary of the layer region specified by the segmentation processing using a predetermined fitting function.

[0292] According to such an aspect, by using the boundary of the layer region obtained by fitting the boundary of the layer region specified in the first tomographic image using a predetermined fitting function, the boundary of the layer region in the first tomographic image can be observed in detail. Thus, while reducing the labor, the layer region in the tomographic structure of the eye to be examined can be specified with high accuracy.

[0293] In the 19th aspect of the embodiment, in any of the 12th to 18th aspects, one or more pieces of boundary candidate information include the boundary of the layer region obtained by sequentially repeating two or more times the setting of the boundary of the layer region specified by the segmentation process performed on the third tomographic image different from the first tomographic image as the boundary of the layer region in the tomographic image adjacent to the third tomographic image in the C-scan direction.

[0294] According to such an aspect, by using the boundary of the layer region specified by the segmentation process performed on the third tomographic image different from the first tomographic image, the boundary of the layer region in the first tomographic image can be observed in detail. Thus, while reducing the labor, the layer region in the tomographic structure of the eye to be examined can be specified with high accuracy.

[0295] In the 20th aspect of the embodiment, in any one of the 12th to 19th aspects, one or more boundary candidate information includes boundaries of layer regions specified by segmentation processing, slice images adjacent to the first tomographic image in the C-scan direction, or slice images arranged by placing one or more slice images in the C-scan direction with respect to the first tomographic image. Boundaries of layer regions in the depth direction specified by performing segmentation processing on the second tomographic image, boundaries of layer regions obtained by fitting the boundaries of layer regions specified by segmentation processing using a predetermined fitting function, and boundaries of layer regions specified by segmentation processing performed on a third tomographic image different from the first tomographic image. It includes boundaries of layer regions obtained by performing an affine transformation on at least one of the boundaries of layer regions obtained by sequentially repeating two or more times the setting of the boundaries of layer regions in the tomographic images adjacent to the third tomographic image in the C-scan direction.

[0296] According to such an aspect, since the boundaries of the layer regions in the first tomographic image can be observed in detail using the boundaries obtained by performing the affine transformation, while reducing the labor, the layer regions in the tomographic structure of the eye to be examined can be specified with high accuracy.

[0297] In the 21st aspect of the embodiment, in any one of the 12th to 20th aspects, the segmentation processing step includes an edge detection step, a boundary candidate specification step, and a boundary specification step. The edge detection step detects edges in the first tomographic image based on the luminance values of the first tomographic image. The boundary candidate specification step specifies two or more boundary candidates of the layer region so that the cost becomes maximum or minimum as it passes through the edge. The boundary specification step specifies the first boundary candidate with the maximum or minimum cost as the boundary of the layer region, and specifies information representing one or more upper boundary candidates when two or more boundary candidates excluding the first boundary candidate are arranged in ascending or descending order based on the cost as one or more boundary candidate information.

[0298] According to such an aspect, edges in the first tomographic image are detected based on the luminance values of the first tomographic image, and the boundary of the layer region of the first tomographic image and one or more boundary candidate information are specified based on the cost that becomes maximum or minimum as it passes through the detected edges. Therefore, while reducing the labor, it becomes possible to accurately specify the layer region in the tomographic structure of the eye to be examined.

[0299] The 22nd aspect of the embodiment is a program for causing a computer to execute each step of the ophthalmic information processing method according to any one of the 12th to 21st aspects.

[0300] According to such an aspect, it becomes possible to provide a program capable of observing the position of the boundary specified by the segmentation process and correcting the above boundary while referring to one or more boundary candidate information.

[0301] The configuration described above is merely an example for preferably implementing the present invention. Therefore, any modifications (omissions, substitutions, additions, etc.) within the scope of the gist of the present invention can be appropriately made. The applicable configuration is selected according to the purpose, for example. Further, depending on the applicable configuration, the effects that are obvious to those skilled in the art and the effects described in this specification can be obtained.

Explanation of Signs

[0302] 1 Ophthalmic device 3 Display device 100, 100a OCT unit 210 Control unit 211 Main control unit 211A Display control unit 220 Image forming unit 230, 230a Data processing unit 232 Segmentation processing unit 232A Edge detection unit 232B Boundary candidate specifying unit 232C Boundary specifying unit 233 Correction processing unit 240A Display unit 240B Operation Unit E Eye Examination

Claims

1. An acquisition unit that acquires image data of a first tomographic image obtained by performing optical coherence tomography on an eye to be examined; A segmentation processing unit that identifies a boundary of a layer region in the depth direction by performing segmentation processing on the first tomographic image based on the image data; A display control unit that causes a display means to display, in a distinguishable manner, the boundary of the layer region specified by the segmentation processing unit and one or more pieces of boundary candidate information indicating a correction candidate for the boundary; An ophthalmic information processing apparatus comprising:

2. The display control unit causes the display means to display the boundary of the layer region and the one or more pieces of boundary candidate information in an overlapping manner. The ophthalmic information processing apparatus according to claim 1, characterized in that.

3. The display control unit causes the display means to display each of the boundary of the layer region and the one or more pieces of boundary candidate information in a different manner. The ophthalmic information processing apparatus according to claim 1, characterized in that.

4. An operation unit; A correction processing unit that corrects the boundary of the layer region based on boundary candidate information specified based on user operation information for the operation unit from among the one or more pieces of boundary candidate information; comprising The ophthalmic information processing apparatus according to any one of claims 1 to 3, characterized in that.

5. The one or more pieces of boundary candidate information include boundaries of layer regions in the depth direction specified by performing the segmentation processing on a slice image adjacent to the first tomographic image in the C-scan direction or a second tomographic image arranged with one or more slice images placed in the C-scan direction with respect to the first tomographic image. The ophthalmic information processing apparatus according to claim 4, characterized in that.

6. The above-mentioned boundary candidate information of 1 or more includes boundaries of layer regions in the depth direction specified by performing the segmentation process on the second tomographic image of the eye to be examined acquired in the past. The ophthalmic information processing apparatus according to claim 4, characterized in that.

7. The above-mentioned boundary candidate information of 1 or more includes boundaries of the layer regions obtained by fitting the boundaries of the layer regions specified by the segmentation process using a predetermined fitting function. The ophthalmic information processing apparatus according to claim 4, characterized in that.

8. The above-mentioned boundary candidate information of 1 or more includes boundaries of layer regions specified by the segmentation process performed on a third tomographic image different from the first tomographic image, and the boundaries of the layer regions obtained by sequentially repeating two or more times the setting of the boundaries of the layer regions in the tomographic images adjacent in the C-scan direction to the third tomographic image as the boundaries of the layer regions in the tomographic images adjacent in the C-scan direction to the third tomographic image. The ophthalmic information processing apparatus according to claim 4, characterized in that.

9. The above-mentioned boundary candidate information of 1 or more includes boundaries of the layer regions specified by the segmentation process, boundaries of layer regions in the depth direction specified by performing the segmentation process on a slice image adjacent in the C-scan direction to the first tomographic image or a second tomographic image which is a slice image arranged with one or more slice images placed in the C-scan direction with respect to the first tomographic image, boundaries of the layer regions obtained by fitting the boundaries of the layer regions specified by the segmentation process using a predetermined fitting function, and boundaries of the layer regions obtained by performing an affine transformation on at least one of the boundaries of the layer regions obtained by sequentially repeating two or more times the setting of the boundaries of the layer regions specified by the segmentation process performed on a third tomographic image different from the first tomographic image as the boundaries of the layer regions in the tomographic images adjacent in the C-scan direction to the third tomographic image. The ophthalmic information processing apparatus according to claim 4, characterized in that...

10. The segmentation processing unit includes: An edge detection unit that detects an edge in the first tomographic image based on the luminance value of the first tomographic image; A boundary candidate specifying unit that specifies two or more boundary candidates of the layer region such that the cost becomes maximum or minimum as it passes through the edge; A boundary specifying unit that specifies the first boundary candidate where the cost becomes maximum or minimum as the boundary of the layer region, and specifies information representing one or more upper boundary candidates when the two or more boundary candidates excluding the first boundary candidate are arranged in ascending or descending order based on the cost as the one or more boundary candidate information; and The ophthalmic information processing apparatus according to claim 4, characterized in that...

11. An optical system that performs optical coherence tomography on the eye to be examined; An image forming unit that forms the first tomographic image based on the detection result of the interference light obtained by the optical system; The ophthalmic information processing apparatus according to any one of claims 1 to 3; and

12. An acquisition step of acquiring image data of a first tomographic image obtained by performing optical coherence tomography on the eye to be examined; A segmentation processing step of specifying a boundary of a layer region in the depth direction by performing segmentation processing on the first tomographic image based on the image data; A display control step of causing a display means to display the boundary of the layer region specified in the segmentation processing step and the one or more boundary candidate information indicating a correction candidate for the boundary in a distinguishable manner; and

13. The display control step causes the display means to display the boundary of the layer region and the one or more boundary candidate information in an overlapping manner. The ophthalmic information processing method according to claim 12, characterized in that...

14. In the display control step, the boundaries of the layer regions and each of the one or more boundary candidate information are displayed on the display means in different manners. The ophthalmic information processing method according to claim 12, characterized in that...

15. It includes a correction processing step of correcting the boundary of the layer region based on the boundary candidate information specified based on the user's operation information on the operation unit from among the one or more boundary candidate information. The ophthalmic information processing method according to any one of claims 12 to 14, characterized in that...

16. The one or more boundary candidate information includes the boundaries of the depth-direction layer regions specified by performing the segmentation process on a slice image adjacent to the first tomographic image in the C-scan direction or a second tomographic image in which one or more slice images are placed in the C-scan direction with respect to the first tomographic image. The ophthalmic information processing method according to claim 15, characterized in that...

17. The one or more boundary candidate information includes the boundaries of the depth-direction layer regions specified by performing the segmentation process on the second tomographic image of the eye to be examined acquired in the past. The ophthalmic information processing method according to claim 15, characterized in that...

18. The one or more boundary candidate information includes the boundaries of the layer regions obtained by fitting the boundaries of the layer regions specified by the segmentation process using a predetermined fitting function. The ophthalmic information processing method according to claim 15, characterized in that...

19. The boundary candidate information of 1 or more is obtained by sequentially repeating 2 or more times the step of setting the boundary of the layer region specified by the segmentation process performed on a third tomographic image different from the first tomographic image as the boundary of the layer region in a tomographic image adjacent to the third tomographic image in the C-scan direction, and includes the boundary of the layer region thus obtained. The ophthalmic information processing method according to claim 15, characterized in that.

20. The boundary candidate information of 1 or more includes the boundary of the layer region specified by the segmentation process, the boundary of the layer region in the depth direction specified by performing the segmentation process on a slice image adjacent to the first tomographic image in the C-scan direction or a second tomographic image which is a slice image arranged with 1 or more slice images placed in the C-scan direction with respect to the first tomographic image, the boundary of the layer region obtained by fitting the boundary of the layer region specified by the segmentation process using a predetermined fitting function, and the boundary of the layer region obtained by performing an affine transformation on at least one of the boundaries of the layer region obtained by sequentially repeating 2 or more times the step of setting the boundary of the layer region specified by the segmentation process performed on a third tomographic image different from the first tomographic image as the boundary of the layer region in a tomographic image adjacent to the third tomographic image in the C-scan direction. The ophthalmic information processing method according to claim 15, characterized in that.

21. The segmentation process step includes: An edge detection step of detecting an edge in the first tomographic image based on the luminance value of the first tomographic image; A boundary candidate specifying step of specifying 2 or more boundary candidates of the layer region such that the cost becomes maximum or minimum as it passes through the edge; Specifying a first boundary candidate at which the cost becomes maximum or minimum as the boundary of the layer region, and specifying, as the one or more boundary candidate information, information representing one or more upper boundary candidates when the two or more boundary candidates excluding the first boundary candidate are arranged in ascending or descending order based on the cost; a boundary specifying step including The ophthalmic information processing method according to claim 15, characterized in that it is like this. Claim 22 A program for causing a computer to execute each step of the ophthalmic information processing method according to any one of claims 12 to 14.

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