JP6942627B2 - Ophthalmologic imaging equipment, its control method, programs, and recording media - Google Patents

Description

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

Diagnostic imaging occupies an important position in the field of ophthalmology. In recent years, the use of optical coherence tomography (OCT) has been advancing. OCT has come to be used not only for acquiring B-scan images and three-dimensional images of the eye to be inspected, but also for acquiring front images (en-face images) such as C-scan images and shadowgrams.

In addition, a modality for acquiring an image emphasizing a specific part of the eye to be inspected has also been put into practical use. For example, OCT-Angiography, which forms an image in which retinal blood vessels and choroidal blood vessels are emphasized, is attracting attention (see, for example, Patent Document 1). Generally, the tissue (structure) of the scan site does not change with time, but the blood flow portion inside the blood vessel changes with time. In OCT angiography, an image is formed by emphasizing a portion (blood flow signal) in which such a temporal change exists. In addition, OCT angiography is also called OCT motion contrast imaging (motion contrast imaging) or the like. The images acquired by OCT angiography are called angiographic images, angiograms, motion contrast images, and the like.

In a typical conventional OCT angiography, a three-dimensional scan of a predetermined size (for example, 9 mm × 9 mm) is applied to obtain an image representing the three-dimensional distribution of fundus blood vessels. On the other hand, it is desired to acquire a wider range of angiographic images. Panorama photography is known as a technique for acquiring OCT data over a wide range of the fundus (see, for example, Patent Document 2).

Panorama photography is an imaging method in which a three-dimensional scan is applied to a plurality of different areas and a plurality of three-dimensional images obtained thereby are combined to construct a wide-area image. Overlapping areas are set in the areas adjacent to each other, and the relative positions between the adjacent images are determined with respect to the overlapping areas. Also, sequential three-dimensional scans of different regions are typically achieved by moving the fixation position. Wide area images acquired by panoramic photography are called panoramic images, mosaic images, and the like.

By the way, there are individual differences in the size and characteristics of the eyeball, for example, the axial length and diopter (optical power) differ from person to person. Even when a three-dimensional scan of a predetermined size is applied as described above, the range of the fundus actually scanned varies depending on the axial length and diopter.

For example, as shown in FIG. 1, when the OCT measurement light is incident on the eye E1 having the axial length L1 and the eye E2 having the axial length L2 (> L1) at the same angle θ, the fundus of the eye E1 is examined. The height Y2 of the projection position of the measurement light on the fundus of the eye E2 to be inspected is larger than the height Y1 of the projection position of the measurement light in (Y2> Y1). That is, the longer the axial length, the higher the height of the projection position of the measurement light on the fundus. On the other hand, the size of the OCT scan is defined by the maximum deflection angle of the measurement light. Therefore, even if the size conditions of the OCT scan are the same, the range of the fundus actually scanned changes according to the value of the axial length. The same applies to diopter.

Since the actual scan range is affected by the eyeball parameters in this way, the size of the overlapping area in panoramic photography also changes according to the eyeball parameters. For example, when the axial length of the eye to be inspected is long, the actual scanning range is widened, so that the overlapping area is also widened. If the overlapping area becomes wider than necessary, the range actually drawn by the mosaic image becomes narrow, and the efficiency of panoramic shooting decreases.

On the contrary, when the axial length of the eye to be inspected is short, the actual scanning range is narrowed, so that the overlapping area is also narrowed, and in some cases, the overlapping area is eliminated. If the overlapping area becomes narrow, the relative position between adjacent images may not be obtained with sufficient accuracy. Further, when the overlapping area does not exist, the relative position between the adjacent images cannot be determined, and the mosaic image cannot be constructed.

In addition, the region of interest (for example, the center of the macula) to be drawn in the central region of the mosaic image may not be arranged in such a manner.

Special Table 2015-515894 Japanese Unexamined Patent Publication No. 2009-183332

An object of the present invention is to provide a technique capable of setting a plurality of fixation positions for acquiring a mosaic image using OCT, regardless of individual differences in the size and characteristics of the eyeball. It is in.

The first aspect of the embodiment is an ophthalmologic imaging apparatus including a fixation system, an image acquisition unit, a control unit, a drawing position determination unit, a fixation position setting unit, and an image processing unit. The fixation system presents an fixation target to the eye to be inspected. The image acquisition unit acquires an image by applying optical coherence tomography (OCT) to the fundus of the eye to be inspected. The control unit executes a first control that controls the fixation system and the image acquisition unit so as to repeatedly acquire a three-dimensional image of the fundus while moving the fixation target. The drawing position determination unit analyzes the three-dimensional images sequentially acquired by the first control, and determines whether or not a predetermined portion of the fundus is drawn within a predetermined region of the three-dimensional image. When the drawing position determination unit determines that the predetermined part is drawn in the predetermined area, the fixation position setting unit sets the position of the fixation target when the corresponding three-dimensional image is acquired by the image acquisition unit. Based on this, one or more fixation positions are set. The image processing unit processes the image acquired by the image acquisition unit. The control unit controls the fixation system so as to sequentially present two or more fixation targets corresponding to the two or more fixation positions including the one or more fixation positions to the eye to be inspected, and the two or more fixation positions. A second control is performed to control the image acquisition unit so as to acquire a three-dimensional image of the fundus when each of the fixation targets of the above is presented to the eye to be inspected. The image processing unit includes a composition processing unit that forms a composite image of two or more three-dimensional images corresponding to the two or more fixation positions acquired by the second control.

A second aspect of the embodiment is the ophthalmologic imaging apparatus of the first aspect, in which the control unit starts moving the fixation target from a preset initial fixation position in the first control.

A third aspect of the embodiment is the ophthalmologic imaging apparatus of the second aspect, in which the initial fixation position is centered on a position separated by a predetermined distance in a predetermined direction from a predetermined portion of the fundus of a standard eye. This is the fixation position for acquiring a three-dimensional image.

A fourth aspect of the embodiment is the ophthalmologic imaging apparatus of the second or third aspect, for the control unit to acquire a three-dimensional image centered on a predetermined portion before the first control. Preliminary control is performed to control the fixation system and the image acquisition unit so as to acquire a preliminary three-dimensional image of the fundus while presenting the fixation target corresponding to the predetermined fixation position to the eye to be inspected. The image processing unit calculates the deviation of the image of a predetermined portion of the fundus with respect to the center position of the preliminary three-dimensional image. The fixation position setting unit sets the initial fixation position based on the deviation.

A fifth aspect of the embodiment is the ophthalmic imaging apparatus according to any one of the first to fourth aspects, and the control unit determines in the first control in a three-dimensional scan region centered on the fixation target. The image acquisition unit is controlled so that the OCT is applied to the partial region located on the side of the portion.

The sixth aspect of the embodiment is the ophthalmologic imaging apparatus according to any one of the first to fifth aspects, and the control unit obtains a three-dimensional angiographic image of the fundus in the second control. Control the acquisition unit.

A seventh aspect of the embodiment is the ophthalmologic imaging apparatus of the sixth aspect, in which the control unit controls the image acquisition unit so as to acquire a three-dimensional angiographic image of the fundus in the first control.

An eighth aspect of the embodiment is a method of controlling an ophthalmologic imaging apparatus capable of applying optical coherence tomography (OCT) to the fundus of the eye to be examined, the first control step and the drawing position determination step. , A fixation position setting step, a second control step, and a synthesis step. The first control step is to repeatedly acquire a three-dimensional image of the fundus while moving the fixation target. The drawing position determination step analyzes the three-dimensional images sequentially acquired by the first control step, and determines whether or not a predetermined portion of the fundus is visualized within a predetermined region of the three-dimensional image. The fixation position setting step is one or more based on the position of the fixation target when the corresponding three-dimensional image is acquired when it is determined by the drawing position determination step that the predetermined part is drawn in the predetermined area. Set the fixation position of. The second control step causes the eye to be inspected to sequentially present two or more fixation targets corresponding to the two or more fixation positions including the one or more fixation positions, and the two or more fixation targets. A three-dimensional image of the fundus is acquired when each is presented to the eye to be inspected. The compositing step forms a composite image of two or more three-dimensional images corresponding to the two or more fixation positions acquired by the second control step.

A ninth aspect of the embodiment is a program that causes an ophthalmologic imaging apparatus capable of applying optical coherence tomography (OCT) to the fundus of the eye to be examined to execute the control method of the eighth aspect.

A tenth aspect of the embodiment is a computer-readable non-temporary recording medium on which the program of the ninth aspect is recorded.

According to the embodiment, it is possible to preferably set a plurality of fixation positions for acquiring a mosaic image using OCT regardless of individual differences in the size and characteristics of the eyeball.

It is the schematic for demonstrating the background technique. It is the schematic which shows an example of the structure of the ophthalmologic imaging apparatus which concerns on an exemplary embodiment. It is the schematic which shows an example of the structure of the ophthalmologic imaging apparatus which concerns on an exemplary embodiment. It is the schematic which shows an example of the structure of the ophthalmologic imaging apparatus which concerns on an exemplary embodiment. It is the schematic which shows an example of the structure of the ophthalmologic imaging apparatus which concerns on an exemplary embodiment. It is the schematic for demonstrating an example of the operation of the ophthalmologic imaging apparatus which concerns on an exemplary embodiment. It is the schematic for demonstrating an example of the operation of the ophthalmologic imaging apparatus which concerns on an exemplary embodiment. It is the schematic for demonstrating an example of the operation of the ophthalmologic imaging apparatus which concerns on an exemplary embodiment. It is a flowchart which shows an example of the operation of the ophthalmologic imaging apparatus which concerns on an exemplary embodiment. It is the schematic for demonstrating an example of the operation of the ophthalmologic imaging apparatus which concerns on an exemplary embodiment.

The ophthalmologic imaging apparatus according to the exemplary embodiment, its control method, program, and recording medium will be described in detail with reference to the drawings. The ophthalmologic imaging apparatus of the embodiment is an ophthalmologic apparatus having a function of performing optical coherence tomography (OCT). The ophthalmologic imaging apparatus of the embodiment may be capable of performing OCT angiography of the fundus.

Hereinafter, an ophthalmologic imaging apparatus in which a swept source OCT and a fundus camera are combined will be described, but the embodiment is not limited thereto. The type of OCT is not limited to swept source OCT, and may be, for example, spectral domain OCT.

The swept source OCT divides the light from the variable wavelength light source (wavelength sweep light source) into the measurement light and the reference light, and superimposes the return light of the measurement light from the test object on the reference light to generate interference light. This is a method in which this interference light is detected by a balanced photodiode or the like, and the detection data collected in response to the sweeping of the wavelength and the scanning of the measurement light is subjected to Fourier transform or the like to form an image.

Spectral domain OCT divides the light from the low coherence light source into measurement light and reference light, and superimposes the return light of the measurement light from the subject with the reference light to generate interference light, and the spectrum of this interference light. This is a method in which the distribution is detected by a spectroscope and the detected spectral distribution is subjected to Fourier transform or the like to form an image.

As described above, the swept source OCT is an OCT method for acquiring the spectral distribution by time division, and the spectral domain OCT is an OCT method for acquiring the spectral distribution by spatial division. The OCT method that can be used in the embodiment is not limited to these, and it is also possible to adopt an embodiment that uses an arbitrary OCT method (for example, time domain OCT) different from these.

The ophthalmologic photographing apparatus according to the embodiment may or may not have a function of acquiring a photograph (digital photograph) of the eye to be inspected. Typical examples of ophthalmic modalities having the function of acquiring digital photographs include a fundus camera, a scanning laser ophthalmoscope (SLO), a slit lamp microscope, an anterior ocular segment imaging camera, and a surgical microscope. A frontal image such as a fundus photograph can be used for observing the fundus, setting a scan area, tracking, and the like. The ophthalmic modality that can be used in the embodiment is not limited to these, and it is also possible to adopt an embodiment that uses a modality other than ophthalmology.

In the present specification, unless otherwise specified, "image data" and "image" based on the "image data" are not distinguished. Similarly, unless otherwise noted, no distinction is made between the site or tissue of the eye to be inspected and the image representing it.

<composition>
The exemplary ophthalmologic imaging apparatus 1 shown in FIG. 2 includes a fundus camera unit 2, an OCT unit 100, and an arithmetic control unit 200. The fundus camera unit 2 is provided with an optical system and mechanism for acquiring a frontal image of the eye E to be inspected, and an optical system and mechanism for executing OCT. The OCT unit 100 is provided with an optical system and a mechanism for executing OCT. The arithmetic control unit 200 includes one or more processors configured to perform various processes (calculations, controls, etc.). In addition to these, optional members (jaw holder, forehead pad, etc.) for supporting the subject's face, lens unit for switching the site to which OCT is applied (for example, attachment for anterior ocular segment OCT), etc. Elements and units may be provided in the ophthalmologic imaging apparatus 1.

In the present specification, the "processor" is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), a programmable logic device (for example, a SPLD (Simple It means a circuit such as Programmable Logic Device), FPGA (Field Programmable Gate Array)). The processor realizes the function according to the embodiment by reading and executing a program stored in a storage circuit or a storage device, for example.

<Fundus camera unit 2>
The fundus camera unit 2 is provided with an optical system for photographing the fundus Ef of the eye to be inspected E. The acquired digital image of the fundus Ef (called a fundus image, a fundus photograph, etc.) is generally a front image such as an observation image, a photographed image, or the like. The observed image is obtained by taking a moving image using near infrared light. The captured image is a still image using flash light in the visible region.

The fundus camera unit 2 includes an illumination optical system 10 and a photographing optical system 30. The illumination optical system 10 irradiates the eye E to be inspected with illumination light. The photographing optical system 30 detects the return light of the illumination light applied to the eye E to be inspected. The measurement light from the OCT unit 100 is guided to the eye E to be inspected through the optical path in the fundus camera unit 2. The return light of the measurement light projected on the eye E (for example, fundus Ef) is guided to the OCT unit 100 through the same optical path in the fundus camera unit 2.

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

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

The liquid crystal display (LCD) 39 displays a fixation target (fixation target image). A part of the light flux output from the LCD 39 is reflected by the half mirror 33A, reflected by the mirror 32, passes through the photographing focusing lens 31 and the dichroic mirror 55, and passes through the hole portion of the perforated mirror 21. The luminous flux that has passed through the hole of the perforated mirror 21 passes through the dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the fundus Ef. The fixation target is typically used to guide and fix the line of sight. The direction in which the line of sight of the eye E to be examined is guided (and fixed), that is, the direction in which the fixation of the eye E to be examined is promoted is called the fixation position.

By changing the display position of the fixation target image on the screen of the LCD 39, the fixation position of the eye E to be inspected by the fixation target can be changed. Examples of fixation positions include the fixation position for acquiring an image centered on the macula, the fixation position for acquiring an image centered on the optic nerve head, and the position between the macula and the optic nerve head ( There is a fixation position for acquiring an image centered on the fundus (center of the fundus) and a fixation position for acquiring an image of a portion (peripheral part of the fundus) far away from the macula.

A graphical user interface (GUI) or the like for designating at least one of such typical fixation positions can be provided. In addition, a GUI or the like for manually moving the fixation position (display position of the fixation target) can be provided. It is also possible to apply a configuration that automatically sets the fixation position.

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

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

The focus optical system 60 generates a split index used for focus adjustment with respect to the eye E to be inspected. The focus optical system 60 is moved along the optical path (illumination optical path) of the illumination optical system 10 in conjunction with the movement of the imaging focusing lens 31 along the optical path (photographing optical path) of the photographing optical system 30. The reflection rod 67 is inserted and removed from the illumination optical path. When adjusting the focus, the reflecting surface of the reflecting rod 67 is inclined and arranged in the illumination optical path. The focus light output from the LED 61 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, is reflected by the mirror 65, and is reflected by the condensing lens 66. Once imaged on the reflecting surface of, it is reflected. Further, the focus light is reflected by the perforated mirror 21 via the relay lens 20, passes through the dichroic mirror 46, and is projected onto the eye E to be inspected via the objective lens 22. The return light (reflected light from the fundus, etc.) of the focus light from the eye E to be inspected is guided to the image sensor 35 through the same path as the return light of the alignment light. Manual focusing or auto focusing can be executed based on the received light image (split index image).

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

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

The retroreflector 41 is movable in the direction of the arrow shown in FIG. 2, thereby changing the length of the measuring arm. The change in the measurement arm length is used, for example, for correcting the optical path length according to the axial length and adjusting the interference state.

The dispersion compensating member 42, together with the dispersion compensating member 113 (described later) arranged on the reference arm, acts to match the dispersion characteristics of the measurement light LS and the dispersion characteristics of the reference light LR.

The OCT focusing lens 43 is moved along the measuring arm to adjust the focus of the measuring arm. The movement of the photographing focusing lens 31, the movement of the focus optical system 60, and the movement of the OCT focusing lens 43 can be controlled in a coordinated manner.

The optical scanner 44 is substantially located at a position optically conjugate with the pupil of the eye E to be inspected. The optical scanner 44 deflects the measurement light LS guided by the measurement arm. The optical scanner 44 is, for example, a galvano scanner capable of two-dimensional scanning. Typically, the optical scanner 44 includes a one-dimensional scanner for deflecting the measurement light in the ± x direction and a one-dimensional scanner for deflecting the measurement light in the ± y direction. In this case, for example, one of these one-dimensional scanners is arranged at a position optically conjugate with the pupil, or a position optically conjugate with the pupil is arranged between these one-dimensional scanners.

<OCT unit 100>
The exemplary OCT unit 100 shown in FIG. 3 is provided with an optical system for performing swept source OCT. This optical system includes an interference optical system. This interference optical system divides the light from the variable wavelength light source into the measurement light and the reference light, and superimposes the return light of the measurement light projected on the eye E to be examined and the reference light passing through the reference optical path to cause the interference light. Is generated and this interference light is detected. The data (detection signal) obtained by the detection of the interference light is a signal representing the spectrum of the interference light and is sent to the arithmetic control unit 200.

The light source unit 101 includes, for example, a near-infrared wavelength tunable laser that changes the wavelength of emitted light at high speed. 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. Further, the optical L0 is guided by the optical fiber 104 to the fiber coupler 105 and divided into the measurement optical LS and the reference optical LR. The optical path of the measurement light LS is called a measurement arm or the like, and the optical path of the reference light LR is called a reference arm or the like.

The reference light LR generated by the fiber coupler 105 is guided by the optical fiber 110 to the collimator 111, converted into a parallel luminous flux, and guided to the retroreflector 114 via the optical path length correction member 112 and the dispersion compensation member 113. The optical path length correction member 112 acts to match the optical path length of the reference light LR with the optical path length of the measurement light LS. The dispersion compensating member 113, together with the dispersion compensating member 42 arranged on the measurement arm, acts to match the dispersion characteristics between the reference light LR and the measurement light LS. The retroreflector 114 is movable along the optical path of the reference light LR incident on it, thereby changing the length of the reference arm. The change of the reference arm length is used, for example, for correcting the optical path length according to the axial length and adjusting the interference state.

The reference light LR that has passed through the retroreflector 114 is converted from a parallel luminous flux to a focused luminous flux by the collimator 116 via the dispersion compensating member 113 and the optical path length correction member 112, and is incident on the optical fiber 117. The reference light LR incident on the optical fiber 117 is guided by the polarization controller 118 to adjust its polarization state, is guided to the attenuator 120 through the optical fiber 119 to adjust the amount of light, and is guided to the fiber coupler 122 through the optical fiber 121. Be guided.

On the other hand, the measurement optical LS generated by the fiber coupler 105 is guided to the collimator lens unit 40 through the optical fiber 127 and converted into a parallel light beam, and is converted into a parallel light beam, the retroreflector 41, the dispersion compensation member 42, the OCT focusing lens 43, and the optical scanner 44. , And is reflected by the dichroic mirror 46 via the relay lens 45, refracted by the objective lens 22, and projected onto the eye E to be inspected. The measurement light LS is scattered and reflected at various depth positions of the eye E to be inspected. The return light from the eye E to be inspected of the measurement light LS travels in the opposite direction on the measurement arm, is guided to the fiber coupler 105, and reaches the fiber coupler 122 via the optical fiber 128.

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

The detector 125 includes, for example, a balanced photodiode. The balanced photodiode includes a pair of photodetectors that detect each pair of interference light LCs, and outputs the difference between the pair of detection signals obtained by these. The detector 125 sends this output (detection signal such as a difference signal) to the data collection system (DAQ) 130.

A clock KC is supplied to the data collection system 130 from the light source unit 101. The clock KC is generated in the light source unit 101 in synchronization with the output timing of each wavelength swept within a predetermined wavelength range by the tunable light source. The light source unit 101, for example, branches the light L0 of each output wavelength to generate two branched lights, optically delays one of the branched lights, synthesizes the branched lights, and produces the obtained combined light. It detects and generates a clock KC based on the detected signal. The data collection system 130 executes sampling of the detection signal (difference signal) input from the detector 125 based on the clock KC. The data collection system 130 sends the data obtained by this sampling to the arithmetic control unit 200.

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

<Calculation control unit 200>
The arithmetic control unit 200 controls each part of the fundus camera unit 2, the display device 3, and the OCT unit 100. In addition, the arithmetic control unit 200 executes various arithmetic processes. For example, the arithmetic control unit 200 performs signal processing such as Fourier transform on the spectral distribution based on the sampling data group obtained by the data collection system 130 for each series of wavelength scans (for each A line), thereby performing each A. Form a reflection intensity profile in the line. Further, the arithmetic control unit 200 forms image data by imaging the reflection intensity profile of each A line. The arithmetic processing for that purpose is the same as that of the conventional swept source OCT.

The arithmetic control unit 200 includes, for example, a processor, a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk drive, a communication interface, and the like. Various computer programs are stored in a storage device such as a hard disk drive. The arithmetic control unit 200 may include an operation device, an input device, a display device, and the like.

<Control system>
Examples of the configuration of the control system (processing system) of the ophthalmologic imaging apparatus 1 are shown in FIGS. 4 and 5. The control unit 210, the image forming unit 220, and the data processing unit 230 are provided in, for example, the arithmetic control unit 200.

<Control unit 210>
The control unit 210 includes a processor and controls each unit of the ophthalmologic imaging apparatus 1. The control unit 210 includes a main control unit 211 and a storage unit 212.

<Main control unit 211>
The main control unit 211 includes a processor and controls each element of the ophthalmologic imaging apparatus 1 (including the elements shown in FIGS. 2 to 5). The main control unit 211 is realized by the cooperation between the hardware including the circuit and the control software.

The photographing focusing lens 31 arranged in the photographing optical path and the focusing optical system 60 arranged in the illumination optical path are moved by a photographing focusing drive unit (not shown) under the control of the main control unit 211. The retroreflector 41 provided on the measuring arm is moved by the retroreflector (RR) drive unit 41A under the control of the main control unit 211. The OCT focusing lens 43 arranged on the measuring arm is moved by the OCT focusing driving unit 43A under the control of the main control unit 211. The optical scanner 44 provided on the measuring arm operates under the control of the main control unit 211. The retroreflector 114 arranged on the reference arm is moved by the retroreflector (RR) drive unit 114A under the control of the main control unit 211. Each of these drive units includes an actuator such as a pulse motor that operates under the control of the main control unit 211.

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

<Memory unit 212>
The storage unit 212 stores various types of data. The data stored in the storage unit 212 includes, for example, image data of an OCT image, image data of a fundus image, eye information to be inspected, and the like. The eye test information includes subject information such as patient ID and name, left eye / right eye identification information, electronic medical record information, and the like.

<Image forming unit 220>
The image forming unit 220 forms image data based on the data collected by the data collecting system 130. The image forming unit 220 includes a processor. The image forming unit 220 is realized by the cooperation of the hardware including the circuit and the image forming software.

The image forming unit 220 forms the cross-sectional image data based on the data collected by the data collecting system 130. This processing includes signal processing such as noise removal (noise reduction), filtering, and fast Fourier transform (FFT), as in the conventional swept source OCT.

The image data formed by the image forming unit 220 is a group of images formed by imaging reflection intensity profiles in a plurality of A lines (scan lines along the z direction) arranged in an area to which an OCT scan is applied. A data set containing image data (a group of A-scan image data).

The image data formed by the image forming unit 220 is, for example, one or more B-scan image data, or stack data formed by embedding a plurality of B-scan image data in a single three-dimensional coordinate system. The image forming unit 220 can also perform volume data (voxel data) by performing interpolation processing or the like on the stack data. Stack data and volume data are typical examples of three-dimensional image data represented by a three-dimensional coordinate system.

When OCT angiography is performed, the main control unit 211 repeatedly scans the same area of the fundus Ef a predetermined number of times. The image forming unit 220 can form a motion contrast image based on the data set collected by the data collecting system 130 in this repeated scan. This motion contrast image is an angiographic image that emphasizes the temporal change of the interference signal due to the blood flow of the fundus Ef. Typically, OCT angiography is applied to the three-dimensional region of the fundus Ef to obtain an image showing the three-dimensional distribution of blood vessels in the fundus Ef.

The image forming unit 220 can process three-dimensional image data. For example, the image forming unit 220 can construct new image data by applying rendering to the three-dimensional image data. Rendering methods include volume rendering, maximum value projection (MIP), minimum value projection (MinIP), surface rendering, and multi-section reconstruction (MPR). Further, the image forming unit 220 can construct the projection data by projecting the three-dimensional image data in the z direction (A line direction, depth direction). Further, the image forming unit 220 can construct a shadow gram by projecting a part of the three-dimensional image data in the z direction. A part of the three-dimensional image data projected to construct the shadow gram is set by using, for example, segmentation described later.

When OCT angiography is performed, the image forming unit 220 can construct arbitrary 2D angiographic image data and / or arbitrary pseudo 3D angiographic image data from 3D angiographic image data. Is. For example, the image forming unit 220 can construct two-dimensional angiographic image data representing an arbitrary cross section of the fundus Ef by applying the multi-section reconstruction to the three-dimensional angiographic image data.

<Data processing unit 230>
The data processing unit 230 executes various data processing. For example, the data processing unit 230 can apply image processing or analysis processing to OCT image data, or apply image processing or analysis processing to observation image data or captured image data. The data processing unit 230 includes, for example, at least one of a processor and a dedicated circuit board.

The configuration of the exemplary data processing unit 230 is shown in FIG. The data processing unit 230 of this example includes a drawing position determination unit 231, a fixation position setting unit 232, and an image processing unit 233. The fixation system 250 is configured to present the fixation target to the eye E to be inspected. The fixation system 250 of this example includes an LCD 39 and an optical system for projecting a light flux output from the LCD 39 onto the fundus Ef. Further, the image acquisition unit 260 is configured to acquire an image by applying OCT to the fundus Ef of the eye E to be inspected. The image acquisition unit 260 of this example includes an element group that constitutes a measurement arm provided in the fundus camera unit 2, an element group provided in the OCT unit 100, and an image forming unit 220.

<Drawing position determination unit 231>
The drawing position determination unit 231 determines whether or not a predetermined portion of the fundus Ef is drawn in a predetermined region of the image acquired by the image acquisition unit 260. The image acquisition unit 260 of this example applies a three-dimensional scan to the fundus Ef to acquire a three-dimensional image. The drawing position determination unit 231 determines whether or not a predetermined portion of the fundus Ef is drawn in a predetermined region of the three-dimensional image.

In this example, the predetermined site of the fundus Ef may be, for example, the macula (macula center, fovea centralis), optic nerve papilla (papillary center), desired blood vessel position, or lesion. Typically, the macula is applied.

Further, in this example, the predetermined region of the three-dimensional image may be, for example, a one-dimensional partial region, a two-dimensional partial region, or a three-dimensional partial region in the frame (imaging region) of the three-dimensional image. Typically, a three-dimensional subregion is applied. In this example, a three-dimensional subregion in the frame of the three-dimensional image is preset.

In the first example, the drawing position determination unit 231 first identifies an image region corresponding to a predetermined portion of the fundus Ef by analyzing the three-dimensional image acquired by the image acquisition unit 260. This analysis may include arbitrary processing such as segmentation, pattern matching, threshold processing, and the like. Segmentation is a process of identifying a partial area in an image. Typically, segmentation is utilized to identify an image region that corresponds to a predetermined tissue of the fundus Ef. Next, the drawing position determination unit 231 determines whether or not this image area is included in the predetermined area by comparing the coordinates of the specified image area with the coordinates of the predetermined area.

A typical example will be described. First, the drawing position determination unit 231 applies segmentation to the three-dimensional image acquired by the image acquisition unit 260 to identify an image region corresponding to the inner limiting membrane. Next, the drawing position determination unit 231 specifies the coordinates of the center of the macula based on the shape of the internal limiting membrane region. In the standard eye, the macula is identified as a recess in the inner limiting membrane, and the center of the macula is identified as the deepest part of this recess. Subsequently, the drawing position determination unit 231 uses the three-dimensional coordinate system in which the three-dimensional image is defined to compare the coordinates of the specified macula center with the range of coordinates corresponding to the predetermined region. In other words, the drawing position determination unit 231 determines whether or not the coordinates of the center of the macula are included in the range of coordinates corresponding to the predetermined region. When the coordinates of the center of the macula are included in the range of coordinates corresponding to the predetermined area, it is determined that the center of the macula (predetermined part) is drawn in the predetermined area of this three-dimensional image. On the other hand, when the coordinates of the center of the macula are not included in the range of coordinates corresponding to the predetermined area, it is determined that the center of the macula (predetermined part) is not drawn in the predetermined area of this three-dimensional image.

In this typical example, the predetermined site is one point (center of the macula), but the embodiment is not limited to this, and the predetermined site has a one-dimensional, two-dimensional or three-dimensional spread. May be good. For example, the predetermined site may be the entire macula or the entire optic disc. When the predetermined portion has a spread, the drawing position determination unit 231 may be configured to determine, for example, whether or not at least a part of the predetermined portion is drawn in the predetermined region. As another example, the drawing position determination unit 231 may be configured to determine whether or not the entire predetermined portion is drawn within the predetermined region.

A second example will be described. In the second example, the drawing position determination unit 231 analyzes a predetermined region (or a predetermined region and a region in the vicinity thereof) in the three-dimensional image acquired by the image acquisition unit 260 to obtain a predetermined portion of the fundus Ef. It is determined whether or not the image is drawn within this predetermined area. This analysis includes, for example, a process of searching an image region having a characteristic morphology of a predetermined portion of the fundus Ef within the predetermined region. As a typical example, the depiction position determination unit 231 may be configured to search for an image region exhibiting a comparatively gentle dent, which is a characteristic form of the macula. Alternatively, the depiction position determination unit 231 may be configured to search for an image region exhibiting a relatively steep and large dent, which is a characteristic morphology of the optic nerve head.

The processing that can be executed by the drawing position determination unit 231 is not limited to the above example, and it is possible to determine whether or not a predetermined portion of the fundus Ef is visualized within a predetermined region of the image acquired by the image acquisition unit 260. It may be any processing.

<Fixed position setting unit 232>
The fixation position setting unit 232 sets the fixation position for applying OCT to the fundus Ef. In particular, the fixation position setting unit 232 can set the fixation position for applying panoramic photography to the fundus Ef. The processing that can be executed by the fixation position setting unit 232 of this example will be described later.

<Image processing unit 233>
The image processing unit 233 processes the OCT image acquired by the image acquisition unit 260. Even if the image processing unit 233 can process the fundus image (observation image, captured image, etc.) acquired by the fundus camera unit 2, or process the image acquired by another ophthalmologic imaging device. good.

For example, the image processing unit 233 can apply segmentation to the two-dimensional cross-sectional image data or the three-dimensional image data.

As described above, the image forming unit 220 can project the image region specified by the segmentation in the z direction to construct a shadow gram (frontal angiography image data or the like). Examples of shadowgrams include shadowgrams corresponding to any depth region of the fundus Ef (eg, superficial retina, deep retina, choroidal capillary plate, sclera, etc.) and any tissue (eg, inner border membrane, etc.). Nerve fiber layer, ganglion cell layer, inner reticular layer, inner granule layer, outer plexiform layer, outer granule layer, outer border membrane, retinal pigment epithelium, Bruch's membrane, choroid, choroidal sclera border, sclera, any of these There are shadowgrams corresponding to some of them, at least two or more combinations of these, etc.).

The image processing unit 233 includes an image processing processor and an image analysis processor. The image processing processor is realized by the collaboration between the hardware including the circuit and the image processing software. Further, the image analysis processor is realized by the collaboration between the hardware including the circuit and the image analysis software.

The processing that can be executed by the image processing unit 233 of this example will be described later.

<Synthesis processing unit 2331>
The image processing unit 233 includes a composition processing unit 2331. The composition processing unit 2331 forms a composite image of two or more three-dimensional images acquired corresponding to two or more fixation positions that are different from each other in panoramic photography. The processing that can be executed by the synthesis processing unit 2331 of this example will be described later.

<User interface 240>
The user interface 240 includes a display unit 241 and an operation unit 242. The display unit 241 includes a display device 3. The operation unit 242 includes various operation devices and input devices. The user interface 240 may include a device such as a touch panel in which a display function and an operation function are integrated. It is also possible to build embodiments that do not include at least a portion of the user interface 240. For example, the display device may be an external device connected to the ophthalmologic imaging device.

<About panoramic shooting>
The panoramic shooting that can be performed in this example will be described. In this example, OCT is applied to the fundus Ef in order to set the fixation position for panoramic photography. This preliminary OCT includes, for example, a first preliminary OCT for setting an initial position (initial fixation position) of the fixation target, and a plurality of fixations for a plurality of OCTs performed in panoramic photography. Includes a second preliminary OCT for setting the position. In the second preliminary OCT, the OCT is repeatedly executed while changing the fixation position.

The execution of the first preliminary OCT is optional. The second preliminary OCT may be performed without going through the first preliminary OCT. If the first preliminary OCT is not performed, for example, in the second preliminary OCT, the change of the fixation position can be started from the default initial fixation position. Alternatively, if the first preliminary OCT is not executed, the change of the fixation position may be started from the initial fixation position set by the user in the second preliminary OCT.

On the other hand, when the first preliminary OCT is executed, for example, in the second preliminary OCT, the change of the fixation position is started from the initial fixation position set in the first preliminary OCT. Can be done. Alternatively, when the first preliminary OCT is executed, in the second preliminary OCT, the user corrects the initial fixation position set in the first preliminary OCT, or the first preliminary OCT It may be possible to automatically or manually select one of the initial fixation position set in and the default initial fixation position.

<About the first preliminary OCT, etc.>
An example of the first preliminary OCT will be described. In the first preliminary OCT, the main control unit 211 presents, for example, a first fixation target for acquiring a three-dimensional image centered on a predetermined portion of the fundus Ef to the fundus E, and the fundus Ef. The fixation system 250 and the image acquisition unit 260 are controlled so as to acquire a three-dimensional image (referred to as a preliminary three-dimensional image). In this example, this predetermined site (that is, the first fixation position) is assumed to be the macula (the center of the macula, the fovea centralis), but it may be another site of the fundus (for example, the optic disc or the center of the fundus). good.

The image processing unit 233 calculates the deviation of the image of the macula of the fundus Ef with respect to the center position of the preliminary three-dimensional image.

For example, the image processing unit 233 first analyzes the preliminary three-dimensional image to obtain the coordinates of the pixel corresponding to the center of the macula. This process includes, for example, a process of identifying an image region corresponding to the inner limiting membrane by segmentation, and a process of identifying the coordinates of the center of the macula from the shape of the identified image region.

Subsequently, the image processing unit 233 obtains the difference between the coordinates of the identified center of the macula and the coordinates of the center position of the preliminary three-dimensional image. Here, the center position of the preliminary three-dimensional image may be defined as, for example, the center position of the array region of a plurality of line scans constituting the raster scan, or the center position of the three-dimensional region to be imaged. The difference between the coordinates of the macula center and the coordinates of the center position of the preliminary 3D image corresponds to the actual deviation of the macula center with respect to the center position of the 3D scan applied in the first preliminary OCT.

Based on the deviation obtained by the image processing unit 233, the fixation position setting unit 232 can correct the first fixation position. For example, the fixation position setting unit 232 corrects the first fixation position so that the deviation obtained by the image processing unit 233 is canceled (that is, the deviation becomes zero). As a result, the center position of the three-dimensional scan (center position of panoramic photography) substantially coincides with the portion (macula) corresponding to the first fixation position.

In addition, the fixation position setting unit 232 can correct the default initial fixation position. As a specific example, the fixation position setting unit 232 has a first fixation so that a relative position between the first fixation position and the second fixation position (default peripheral fixation position) is maintained. The same correction amount as the correction amount of the visual position is applied to the second fixation position. That is, the fixation position setting unit 232 applies a correction amount corresponding to the inverse vector of the deviation (vector) obtained by the image processing unit 233 to the second fixation position. In this example, the fixation position obtained by correcting the default initial fixation position can be applied as the initial fixation position in the second preliminary OCT.

The process for setting the initial fixation position applied in the second preliminary OCT is not limited to this example. As an example, it is possible to set the initial fixation position based on the range (size, pattern, etc.) of the three-dimensional scan and the visual position of the macula of the fundus Ef. For example, the fixation position setting unit 232 can calculate the fixation position such that the macula of the fundus Ef is visualized in a predetermined region of the frame of the preliminary three-dimensional image acquired by the first preliminary OCT. can. This calculation process can be executed based on the relative position (deviation) between the predetermined area of the frame and the drawing position of the macula.

When the initial fixation position is set by the fixation position setting unit 232 in this way, it is possible to apply the initial fixation position to execute the second preliminary OCT. Further, as described above, it is also possible to correct this initial fixation position.

The initial fixation position applied to the second preliminary OCT is the fixation position for acquiring a three-dimensional image centered on a position separated by a predetermined distance in a predetermined direction from the macula in the fundus of a standard eye. It may be there.

<About the second preliminary OCT, etc.>
An example of the second preliminary OCT will be described. In the second preliminary OCT, the main control unit 211 first sets the initial fixation position (or the corrected initial fixation position, or the default initial fixation position) set in the first preliminary OCT. The fixation system 250 is controlled so as to present the fixation target corresponding to (etc.) to the eye E to be inspected. That is, the main control unit 211 controls the fixation system 250 so that the fixation target is displayed at the display position (pixels) of the LCD 39 corresponding to the initial fixation position, for example.

Further, the main control unit 211 moves a three-dimensional image of the fundus Ef while moving the fixation target initially presented to the initial fixation position (that is, changing the fixation position starting from the initial fixation position). The fixation system 250 and the image acquisition unit 260 are controlled so that the images are acquired repeatedly. As a result, a plurality of three-dimensional images corresponding to the plurality of fixation positions can be obtained.

Here, the movement pattern of the fixation target may be, for example, a predetermined pattern or a pattern determined based on the three-dimensional images acquired sequentially. In the latter case, for example, the data processing unit 230 (drawing position determination unit 231) first analyzes the three-dimensional image to determine whether or not the macula of the fundus Ef is drawn.

When the macula is not visualized in the three-dimensional image, for example, the data processing unit 230 (fixation position setting unit 232) determines the relative position between the macula and the initial fixation position, and the fixation position from the initial fixation position. Based on the movement contents (movement direction, movement amount) up to, the next fixation position can be determined so that the macula is visualized in the next acquired three-dimensional image. This process can be repeated until the macula is visualized on the three-dimensional image. Alternatively, the main control unit 211 may increase the size of the three-dimensional scan.

When the yellow spot is drawn in the three-dimensional image, for example, the drawing position determination unit 231 analyzes the three-dimensional image and determines whether the yellow spot is drawn in a predetermined region of the three-dimensional image. This process can be executed as described above.

When the macula is not drawn in the predetermined area of the three-dimensional image, for example, the data processing unit 230 (fixation position setting unit 232) acquires it next based on the relative position between the drawing position of the macula and the predetermined area. It is possible to determine the next fixation position such that the macula is visualized in a predetermined region of the three-dimensional image to be formed. This process can be repeated until the macula is visualized within the predetermined area.

When the macula is drawn in a predetermined area of the three-dimensional image, the fixation position setting unit 232 is one or more for panoramic shooting based on the position of the fixation target when the three-dimensional image is acquired. The fixation position of can be set.

A specific example of such processing will be described. The symbol Mc shown in FIG. 6 indicates the position of the macula (center of the macula) of the fundus Ef. Reference numeral 300 indicates a position of the fixation target (fixation position). Reference numeral 301 indicates a three-dimensional scan range centered on the fixation position 300. Reference numeral 302 indicates a predetermined area in the three-dimensional scan range 301.

In the example shown in FIG. 6, the macula Mc is arranged outside the three-dimensional scan range 301, and the macula is not depicted in the three-dimensional image obtained by applying OCT to the three-dimensional scan range 301. In this case, for example, the fixation position setting unit 232 sets the fixation position based on the information obtained in the first preliminary OCT and the movement content of the fixation target up to the current stage in the second preliminary OCT. A new fixation position closer to the macula Mc than 300 can be set. With this new fixation position applied, a new 3D scan is applied to acquire a new 3D image, and the same process is executed.

By repeatedly executing the above series of processes until a three-dimensional image in which the macula is drawn is obtained, a three-dimensional image in which the macula is drawn can be obtained. An example of such a three-dimensional image is shown in FIG. The symbol Mc shown in FIG. 7 indicates the macula as in FIG. Reference numeral 310 indicates the position of the fixation target (fixation position) at this time. Reference numeral 311 indicates a three-dimensional scan range centered on the fixation position 310. Reference numeral 312 indicates a predetermined region in the three-dimensional scan range 311.

In the example shown in FIG. 7, the macula Mc is visualized outside the predetermined region 312. In this case, for example, the fixation position setting unit 232 is new so that the macula Mc is drawn in the predetermined area of the three-dimensional image based on the relative position between the drawing position of the macula Mc and the predetermined area 312. The fixation position can be set. With this new fixation position applied, a new 3D scan is applied to acquire a new 3D image, and the same process is executed.

The above series of processes is repeatedly executed until a three-dimensional image in which the macula is depicted in a predetermined area is obtained. As a result, as illustrated in FIG. 8, a three-dimensional image 321 in which the macula Mc is visualized in the predetermined region 322 is obtained. Reference numeral 320 indicates the fixation position at this time. The fixation position setting unit 232 can set the fixation position 320 as one of a plurality of fixation positions for panoramic photography.

The position of the predetermined region is set closer to the macula with respect to the fixation position. Further, the size of the predetermined region is set according to, for example, the size of the overlapping region (margin) for synthesizing a plurality of images in panoramic shooting.

The fixation position setting unit 232 can set two or more of a plurality of fixation positions for panoramic photography. For example, when the fixation position 320 illustrated in FIG. 8 is set as the fixation position for panoramic photography, the fixation position setting unit 232 is based on the relative position between the fixation position 320 and the macula Mc. , Other fixation positions for panoramic photography can be set.

As a typical example thereof, the fixation position setting unit 232 is used for panoramic photography at a position symmetrical to the fixation position 320 with respect to the macula Mc on the first straight line passing through the fixation position 320 and the macula Mc. The fixation position can be set. Further, the fixation position setting unit 232 is separated from the macula Mc by the same distance as the distance between the macula Mc and the fixation position 320 on the second straight line orthogonal to the first straight line at the position of the macula Mc. At least one of the two positions can be set as the fixation position for panoramic photography.

It is also possible to configure the fixation position for panoramic photography so that the user can arbitrarily set it.

<motion>
The operation of the ophthalmologic imaging apparatus 1 according to the present embodiment will be described. An example of the operation of the ophthalmologic imaging device 1 is shown in FIG. It is assumed that general preparatory processes such as patient information input, alignment, focus adjustment, interference sensitivity adjustment, and z position adjustment have already been completed.

(S1: Perform the first preliminary OCT)
First, the ophthalmologic imaging apparatus 1 executes the first preliminary OCT described above. The first preliminary OCT is performed to set the initial position (initial fixation position) of the fixation movement applied in the second preliminary OCT. In the first preliminary OCT of this example, the main control unit 211 controls the fixation system 250 so as to present the default fixation target for macular photography to the eye E to be examined, and the fixation for macular photography is achieved. The image acquisition unit 260 is controlled so as to apply a three-dimensional scan to the fundus Ef of the eye E to be inspected on which the target is presented. Thereby, a preliminary three-dimensional image is obtained.

Here, the default fixation target for macular photography is typically a visible bright spot displayed at the center position of the display screen of the LCD 39 (that is, the position on the optical axis of the optical path branched by the half mirror 33A). Is. However, the default macular imaging target is not limited to this. Also, the 3D scan applied to the first preliminary OCT is typically, but is not limited to, a raster scan.

(S2: Set the initial fixation position)
The main control unit 211 sends the preliminary three-dimensional image acquired in the first preliminary OCT of step S1 to the data processing unit 230. The image processing unit 233 calculates the deviation of the image of the macula of the fundus Ef with respect to the center position of the preliminary three-dimensional image. For example, the image processing unit 233 identifies the position of the pixel corresponding to the center of the macula by analyzing the preliminary three-dimensional image, and calculates the deviation of the pixel with respect to the center position of the preliminary three-dimensional image.

The fixation position setting unit 232 is the fixation position corresponding to the default fixation target for macular photography (that is, the display position of the visible bright spot on the display screen of the LCD 39) based on the deviation calculated by the image processing unit 233. ) Is corrected. The position of the fundus Ef (macula) corresponding to the corrected fixation target for macular imaging substantially corresponds to the central position of the panoramic imaging performed in the subsequent stage. That is, by applying the translation of the direction and distance corresponding to the inverse vector of the vector represented by the deviation to the default fixation target for yellow spot photography, the default is that the yellow spot is drawn at the center position of the three-dimensional image. The position of the fixation target for yellow spot photography is corrected.

Further, the fixation position setting unit 232 makes the same correction for the default peripheral fixation position (second fixation position). For example, the fixation position setting unit 232 corrects the default peripheral fixation position (that is, the display position of the visible bright spot on the display screen of the LCD 39) based on the deviation calculated by the image processing unit 233. That is, the peripheral fixation position is corrected by applying the translation of the direction and the distance corresponding to the inverse vector of the vector represented by the deviation to the default peripheral fixation position. The corrected default peripheral fixation position is set to the initial fixation position for the second preliminary OCT.

(S3: Start the second preliminary OCT)
When the setting of the initial fixation position (for example, correction of the peripheral fixation position) is completed, the process shifts to the second preliminary OCT. A second preliminary OCT is performed to set a plurality of fixation positions for panoramic imaging.

The main control unit 211 displays the visible bright spot at the position (pixel) of the display screen of the LCD 39 corresponding to the peripheral fixation position corrected in step S2.

(S4: Acquire 3D image)
Further, the main control unit 211 controls the image acquisition unit 260 so as to apply a three-dimensional scan to the fundus Ef to form a three-dimensional image.

The imaging method applicable to the second preliminary OCT is not limited to the general three-dimensional OCT scan, and may be, for example, three-dimensional OCT angiography. Alternatively, other imaging methods (eg, functional OCT) can be applied to the second preliminary OCT.

(S5: Is the macula depicted?)
The drawing position determination unit 231 analyzes the three-dimensional image acquired in step S4 and determines whether or not the macula of the fundus Ef is drawn in the three-dimensional image. When it is determined that the macula is not visualized in the three-dimensional image (S5: No), the process proceeds to step S6. On the other hand, when it is determined that the macula is visualized in the three-dimensional image (S5: Yes), the process proceeds to step S7.

(S6: Change the fixation position)
When it is determined in step S5 that the macula is not drawn in the three-dimensional image (S5: No), the fixation position setting unit 232 fixes the macula so that the yellow spot is drawn in the next acquired three-dimensional image. Change the position.

The series of processes of steps S4 to S6 are repeatedly executed, for example, until it is determined as "Yes" in step S5. Here, if this series of processes is repeated a predetermined number of times, or if this series of processes is repeated for a predetermined time, error determination can be performed.

(S7: Is the macula drawn in the predetermined area?)
When it is determined in step S5 that the macula is drawn in the three-dimensional image (S5: Yes), the drawing position determination unit 231 determines whether the macula is drawn in a predetermined region of the three-dimensional image. When it is determined that the macula is drawn in a predetermined area of the three-dimensional image (S7: Yes), the process proceeds to step S8.

On the other hand, when it is determined that the macula is not drawn in the predetermined region of the three-dimensional image (S7: No), the process proceeds to step S6. The series of processes of steps S4 to S7 are repeatedly executed, for example, until it is determined as "Yes" in step S7. Here, if this series of processes is repeated a predetermined number of times, or if this series of processes is repeated for a predetermined time, error determination can be performed.

(S8: Set multiple fixation positions for panoramic shooting)
When it is determined that the macula is drawn in a predetermined area of the three-dimensional image (S7: Yes), the process shifts to the setting of the fixation position for panoramic photography. The fixation position setting unit 232 has a plurality of fixation position setting units 232 for panoramic shooting based on the fixation position when a three-dimensional image determined to have a macula drawn in a predetermined area is acquired by the image acquisition unit 260. Set the fixation position.

For example, as shown in FIG. 10, the first peripheral fixation position 401 located at the lower left of the macula 400 (fixation position for macula photography) is set from the movement of the fixation target starting from the peripheral fixation position. Suppose. The first peripheral fixation position 401 is set at a position separated from the macula 400 in the lower left direction by a distance T. In this case, the fixation position setting unit 232 sets the second peripheral fixation position 402 at a position separated from the macula 400 in the upper left direction by a distance T, and (2) distances T from the macula 400 in the upper right direction. The third peripheral fixation position 403 can be set at a position separated by a distance, and (3) the fourth peripheral fixation position 404 can be set at a position separated by a distance T in the lower right direction from the macula 400.

The number of the plurality of peripheral fixation positions is not limited to four, and the arrangement of the plurality of peripheral fixation positions is not limited to the arrangement shown in FIG. In general, setting (correcting) a plurality of peripheral fixation positions according to a preset arrangement of a plurality of peripheral fixation positions (for example, a default arrangement, an arrangement specified by a user or an ophthalmologic imaging device 1). Is possible.

(S9: Perform panoramic shooting to acquire multiple 3D images)
The main control unit 211 controls the fixation system 250 so as to sequentially present a plurality of fixation targets corresponding to the plurality of (peripheral) fixation positions set in step S8 to the eye E to be inspected, and these The image acquisition unit 260 is controlled so as to acquire a three-dimensional image of the fundus Ef when each of the fixation targets of the above is presented to the eye E to be inspected.

As an example, a case where the four peripheral fixation positions 401 to 404 shown in FIG. 10 are applied to panoramic photography will be described.

First, the main control unit 211 controls the fixation system 250 so as to present the first peripheral fixation target corresponding to the first peripheral fixation position 401, and further, the first peripheral fixation target is presented. The image acquisition unit 260 is controlled so as to execute the three-dimensional scan in this state. As a result, the first peripheral three-dimensional image corresponding to the first peripheral scan range 411 shown in FIG. 10 is acquired.

Next, the main control unit 211 controls the fixation system 250 so as to present the second peripheral fixation target corresponding to the second peripheral fixation position 402, and further, the second peripheral fixation target The image acquisition unit 260 is controlled so as to execute the three-dimensional scan in the presented state. As a result, a second peripheral three-dimensional image corresponding to the second peripheral scan range 412 shown in FIG. 10 is acquired.

Subsequently, the main control unit 211 controls the fixation system 250 so as to present the third peripheral fixation target corresponding to the third peripheral fixation position 403, and further, the third peripheral fixation target sets the third peripheral fixation target. The image acquisition unit 260 is controlled so as to execute the three-dimensional scan in the presented state. As a result, a third peripheral three-dimensional image corresponding to the third peripheral scan range 413 shown in FIG. 10 is acquired.

Finally, the main control unit 211 controls the fixation system 250 so as to present the fourth peripheral fixation target corresponding to the fourth peripheral fixation position 404, and further, the fourth peripheral fixation target sets the fourth peripheral fixation target. The image acquisition unit 260 is controlled so as to execute the three-dimensional scan in the presented state. As a result, a fourth peripheral three-dimensional image corresponding to the fourth peripheral scan range 414 shown in FIG. 10 is acquired.

As shown in FIG. 10, two peripheral three-dimensional images adjacent to each other have overlapping regions (margins) having a width suitable for synthesizing them.

(S10: Form a composite image)
The compositing processing unit 2331 forms a composite image (mosaic image) of a plurality of three-dimensional images acquired in step S9. As an example, in the example shown in FIG. 10, the synthesis processing unit 2331 synthesizes the first to fourth peripheral three-dimensional images to form a single three-dimensional image. It is also possible to combine any two or more three-dimensional images among the plurality of three-dimensional images acquired in step S9.

The process of synthesizing a plurality of 3D images includes, for example, matching of overlapping regions using image correlation and the like, and positioning of peripheral 3D images using the result of this matching, as in the conventional image synthesizing technique. , Including a compositing process with these peripheral three-dimensional images.

(S11: Display / save composite image)
The main control unit 211 can display the composite image formed in step S10 on the display unit 241. Further, the main control unit 211 controls to store the composite image in the storage unit 212, to transmit the composite image to an external device, and to record the composite image on the recording medium. Is possible.

Further, the main control unit 211 can display a part or all of the plurality of three-dimensional images formed in step S9 on the display unit 241. This completes the process related to this example.

<Action / effect>
The operation and effect of the ophthalmologic imaging apparatus 1 according to the present embodiment will be described.

The ophthalmologic imaging apparatus (1) according to the present embodiment includes a fixation system (250), an image acquisition unit (260), a control unit (main control unit 211), a drawing position determination unit (231), and fixation. It includes a position setting unit (232) and an image processing unit (233).

The fixation system (250) presents an fixation target to the eye to be inspected (E). The image acquisition unit (260) acquires an image by applying optical coherence tomography (OCT) to the fundus (Ef) of the eye to be inspected (E).

As the first control (second preliminary OCT), the control unit (211) moves the fixation target and repeatedly acquires a three-dimensional image of the fundus (Ef), and the fixation system (250) and the image. The acquisition unit (260) is controlled.

The drawing position determination unit (231) analyzes the three-dimensional images sequentially acquired by the first control, and a predetermined part (macula, etc.) of the fundus (Ef) is drawn in a predetermined region of the three-dimensional image. Determine if it is.

When the fixation position setting unit (232) determines that the predetermined portion is drawn in the predetermined area of the three-dimensional image by the drawing position determination unit (231), the three-dimensional image is determined by the image acquisition unit (260). One or more fixation positions for panoramic photography are set based on the position of the fixation target when acquired by. The fixation position setting unit (232) can also set two or more fixation positions for panoramic photography. For example, the fixation position setting unit (232) has two or more peripheral fixation positions including one or more of the first peripheral fixation position 401 and the second to fourth peripheral fixation positions 402 to 404. Can be set. It can also be configured so that the user can set at least one of a plurality of fixation positions for panoramic photography.

The image processing unit (233) processes the image acquired by the image acquisition unit (260). The image processing unit (233) includes a compositing processing unit (2331).

As the second control (panoramic shooting), the control unit (211) has two or more fixation positions (first to fourth) including one or more fixation positions set by the fixation position setting unit (232). The fixation system (250) is controlled so that two or more fixation targets (first to fourth peripheral fixation targets) corresponding to the peripheral fixation positions 401 to 404) are sequentially presented to the eye to be inspected (E). And, when each of the two or more fixation targets (first to fourth peripheral fixation targets) is presented to the eye to be inspected (E), a three-dimensional image of the fundus (Ef) is acquired. The image acquisition unit (260) is controlled.

The synthesis processing unit (2331) has two or more three-dimensional images (first to fourth) corresponding to two or more fixation positions (first to fourth peripheral fixation positions 401 to 404) acquired by the second control. A composite image (mosaic image) of the fourth peripheral three-dimensional image) is formed.

According to such an embodiment, a plurality of fixation positions for panoramic photography can be set by actually performing the first control (second preliminary OCT). Thereby, regardless of individual differences such as eyeball size information such as axial length and eyeball characteristic information such as diopter, it is possible to preferably set a plurality of fixation positions for acquiring a mosaic image using OCT. Is possible.

In the present embodiment, the control unit (211) may be configured to start the movement of the fixation target from a preset initial fixation position in the first control (second preliminary OCT). ..

Further, in the present embodiment, the initial fixation position is a fixation position for acquiring a three-dimensional image centered on a position separated by a predetermined distance in a predetermined direction from a predetermined portion of the fundus of a standard eye. good.

Further, in the present embodiment, before the first control (second preliminary OCT), the control unit (211) is set to acquire a three-dimensional image centered on a predetermined portion of the fundus (Ef). The fixation system (250) and the image acquisition unit (260) are controlled so as to acquire a preliminary three-dimensional image of the fundus (Ef) while presenting the fixation target corresponding to the fixation position of It may be configured to perform preliminary control (first preliminary OCT). Further, the image processing unit (233) may be configured to calculate the deviation of the image of a predetermined portion of the fundus (Ef) with respect to the center position of the preliminary three-dimensional image. In addition, the fixation position setting unit (232) may be configured to set the initial fixation position based on this deviation.

According to such a configuration, the initial fixation position is set by using the preliminary three-dimensional image obtained by the second control (first preliminary OCT), and the second preliminary OCT is executed. be able to. Thereby, it is possible to set a suitable initial fixation position regardless of individual differences in the eyeball parameters of the eye to be inspected. A suitable initial fixation position is, for example, a predetermined portion of the fundus of the eye to be examined inside or near a predetermined region in a three-dimensional image obtained by performing a three-dimensional scan with the initial fixation position applied. It corresponds to the case where it is depicted.

In the present embodiment, the control unit (211) is located on the side of a predetermined portion of the fundus (Ef) in the three-dimensional scan region centered on the fixation target in the first control (second preliminary OCT). The image acquisition unit (260) may be configured to control the image acquisition unit (260) so as to apply OCT to the partial region. For example, in the first peripheral scan range 411 shown in FIG. 10, OCT can be applied to any partial region located on the side of the macula 400. As this partial area, for example, a rectangular area having the upper right vertex of the first peripheral scan range 411 as one vertex can be set. Typically, this rectangular region is set so that a predetermined portion of the fundus (Ef) includes the predetermined region to be visualized therein.

According to such a configuration, instead of scanning the entire three-dimensional scan area, it is only necessary to perform OCT on only a part of the three-dimensional scan area, so that the time required for the first control (second preliminary OCT) can be increased. Can be shortened. This time saving effect can be said to be remarkable, for example, when three-dimensional OCT angiography is performed in the first control (second preliminary OCT).

In the present embodiment, the control unit (211) may control the image acquisition unit (260) so as to acquire a three-dimensional angiographic image of the fundus (Ef) in the second control (panoramic photography).

With such a configuration, it is possible to suitably acquire a three-dimensional angiographic image (mosaic image) over a wide range of the fundus.

Further, in the present embodiment, the control unit (211) may control the image acquisition unit (260) so as to acquire a three-dimensional angiographic image of the fundus (Ef) in the first control.

According to such a configuration, it is possible to set the fixation position for panoramic photography by utilizing the distribution of the fundus blood vessels. Further, when the three-dimensional angiographic image acquired in the first control is used for constructing a mosaic image, the imaging time can be significantly shortened.

The method for controlling the ophthalmologic imaging device according to the present embodiment is a method for controlling the ophthalmologic imaging device (1) capable of applying optical coherence tomography (OCT) to the fundus (Ef) of the eye to be inspected (E). The first control step, the drawing position determination step, the fixation position setting step, the second control step, and the synthesis step are included.

The first control step controls the ophthalmologic imaging apparatus (1) so as to repeatedly acquire a three-dimensional image of the fundus (Ef) while moving the fixation target. The first control step may include any process relating to the second preliminary OCT described in this embodiment.

In the drawing position determination step, the three-dimensional images sequentially acquired by the first control step are analyzed, and whether a predetermined part (macula, etc.) of the fundus (Ef) is drawn in a predetermined region of the three-dimensional image. The ophthalmologic imaging apparatus (1) is controlled so as to make a determination. The drawing position determination step may include any processing related to the determination of the drawing position described in the present embodiment.

In the fixation position setting step, when it is determined by the drawing position determination step that a predetermined part (macula, etc.) of the fundus (Ef) is drawn in a predetermined area of the three-dimensional image, this three-dimensional image is acquired. The ophthalmologic imaging apparatus (1) is controlled so as to set one or more fixation positions based on the position of the fixation target at the time. The fixation position setting step may include any processing related to fixation position setting described in the present embodiment.

The second control step is two or more corresponding to two or more fixation positions (first to fourth peripheral fixation positions 401 to 404) including one or more fixation positions set in the fixation position setting step. (1st to 4th peripheral fixation targets) are sequentially presented to the eye to be inspected (E), and each of 2 or more fixation targets (1st to 4th peripheral fixation targets). The ophthalmologic imaging apparatus (1) is controlled so that the OCT is executed so as to acquire a three-dimensional image of the fundus (Ef) when is presented to the eye to be inspected (E). The second control step may include any processing related to panoramic photography described in the present embodiment.

The synthesis step is a combination of two or more three-dimensional images (first to fourth) corresponding to two or more fixation positions (first to fourth peripheral fixation positions 401 to 404) acquired by the second control step. The ophthalmologic imaging apparatus (1) is controlled so as to form a composite image (mosaic image) of the peripheral three-dimensional image). The compositing step may include any process relating to image compositing described in this embodiment.

It is possible to create a program that causes the ophthalmologic imaging apparatus according to the present embodiment to execute such a control method. It is also possible to create a computer-readable non-temporary recording medium on which such a program is recorded. The non-temporary recording medium may be in any form, and examples thereof include a magnetic disk, an optical disk, a magneto-optical disk, and a semiconductor memory.

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

1 Ophthalmology imaging device 210 Control unit 211 Main control unit 230 Data processing unit 231 Drawing position determination unit 232 Fixed vision position setting unit 233 Image processing unit 2331 Synthesis processing unit 250 Fixed vision system 260 Image acquisition unit

Claims (10)

The fixation system that presents the fixation target to the eye to be inspected,
An image acquisition unit that applies optical coherence tomography (OCT) to the fundus of the eye to be inspected to acquire an image, and an image acquisition unit.
A control unit that executes a first control for controlling the fixation system and the image acquisition unit so as to repeatedly acquire a three-dimensional image of the fundus while moving the fixation target.
A drawing position determination unit that analyzes three-dimensional images sequentially acquired by the first control and determines whether or not a predetermined part of the fundus is drawn within a predetermined region of the three-dimensional image.
When the drawing position determination unit determines that the predetermined portion is drawn in the predetermined region, the position of the fixation target when the corresponding three-dimensional image is acquired by the image acquisition unit is used. A fixation position setting unit that sets one or more fixation positions, and a fixation position setting unit,
Including an image processing unit that processes an image acquired by the image acquisition unit,
The control unit controls the fixation system so as to sequentially present two or more fixation targets corresponding to the two or more fixation positions including the one or more fixation positions to the eye to be inspected. A second control for controlling the image acquisition unit to acquire a three-dimensional image of the fundus when each of the two or more fixation targets is presented to the eye to be inspected is executed.
The image processing unit includes a composite processing unit that forms a composite image of two or more three-dimensional images corresponding to the two or more fixation positions acquired by the second control. .. The ophthalmologic imaging device according to claim 1, wherein the control unit starts the movement of the fixation target from a preset initial fixation position in the first control. The claim is characterized in that the initial fixation position is a fixation position for acquiring a three-dimensional image centered on a position separated by a predetermined distance in a predetermined direction from a predetermined portion of the fundus of a standard eye. 2. The ophthalmologic imaging apparatus according to 2. Prior to the first control, the control unit presents a fixation target corresponding to a predetermined fixation position for acquiring a three-dimensional image centered on the predetermined portion to the eye to be inspected, and the fundus. Preliminary control for controlling the optometry system and the image acquisition unit is executed so as to acquire a preliminary three-dimensional image of the above.
The image processing unit calculates the deviation of the image of the predetermined portion of the fundus with respect to the center position of the preliminary three-dimensional image.
The ophthalmologic imaging apparatus according to claim 2 or 3, wherein the fixation position setting unit sets the initial fixation position based on the deviation. In the first control, the control unit controls the image acquisition unit so as to apply OCT to a partial region located on the side of the predetermined portion in the three-dimensional scan region centered on the fixation target. The ophthalmologic imaging apparatus according to any one of claims 1 to 4. The ophthalmologic imaging according to any one of claims 1 to 5, wherein the control unit controls the image acquisition unit so as to acquire a three-dimensional angiographic image of the fundus in the second control. Device. The ophthalmologic imaging apparatus according to claim 6, wherein the control unit controls the image acquisition unit so as to acquire a three-dimensional angiographic image of the fundus in the first control. A method of controlling an ophthalmologic imaging apparatus capable of applying optical coherence tomography (OCT) to the fundus of an eye to be examined.
The first control step of repeatedly acquiring the three-dimensional image of the fundus while moving the fixation target, and
A drawing position determination step of analyzing three-dimensional images sequentially acquired by the first control step to determine whether or not a predetermined part of the fundus is visualized within a predetermined region of the three-dimensional image.
When it is determined by the drawing position determination step that the predetermined portion is drawn in the predetermined area, one or more fixations are made based on the position of the fixation target when the corresponding three-dimensional image is acquired. The fixation position setting step to set the position and the fixation position setting step
Two or more fixation targets corresponding to two or more fixation positions including the one or more fixation positions are sequentially presented to the eye to be inspected, and each of the two or more fixation targets is presented to the eye to be inspected. A second control step of acquiring a three-dimensional image of the fundus when presented, and
A control method for an ophthalmologic imaging apparatus, comprising a composite step of forming a composite image of two or more three-dimensional images corresponding to the two or more fixation positions acquired by the second control step. A program for causing an ophthalmologic imaging apparatus capable of applying optical coherence tomography (OCT) to the fundus of an eye to be examined to execute the control method according to claim 8. A computer-readable non-temporary recording medium on which the program according to claim 9 is recorded.

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