JP7325675B2 - ophthalmic imaging equipment - Google Patents

Description

The present invention relates to an ophthalmic imaging apparatus.

The importance of image diagnosis and image analysis is increasing in ophthalmologic care. In particular, the application of optical coherence tomography (OCT) to ophthalmology is accelerating this trend. OCT enables three-dimensional imaging and three-dimensional structural analysis and functional analysis of an eye to be examined, and is very effective in obtaining distributions of various measurement values, for example.

In recent years, in order to enable observation of a wide range from the center to the periphery of the fundus, the expansion of the OCT scanning range, that is, the widening of the angle of view of OCT, has been promoted. To widen the angle of view, in addition to increasing the B-scan length (line scan length), it is also required to increase the depth range according to the bowl-shaped shape of the fundus. However, there are limits to widening the angle of view, such as the need to scan through the pupil.

Therefore, a technique is used in which a plurality of areas different from each other are scanned, a plurality of images are constructed, and these images are combined to obtain an image of a wide range (see, for example, Patent Document 1). This technique is called montage, panorama synthesis, or the like.

On the other hand, considering the bowl-shaped shape of the fundus and the aberration distribution of the eye, when performing photography for montage (called montage photography), it is necessary to adjust the focal position, OCT optical path length, polarization conditions, etc. every time the imaging region is changed. It is necessary to adjust the conditions. Note that the aberration distribution of the eye is shown in, for example, Non-Patent Document 1, and it is known that the amount of defocus greatly differs between the central portion and the peripheral portion of the fundus.

Here, while optical scanners that generate OCT scans can operate at extremely high speeds, focus adjustment and optical path length adjustment are accompanied by movement of optical elements by actuators, so it takes longer than the operation of optical scanners. . Therefore, even though focus adjustment and optical path length adjustment are necessary processes for improving image quality, they are a bottleneck for speeding up montage shooting. can be a neck.

In addition, assuming that a constant B-scan length is applied, considering the shape of the fundus, the center of the fundus does not require a large depth range, whereas the periphery of the fundus requires a large depth range. Conversely, since the depth range (A-scan length) that can be scanned at one time is usually constant, a long B-scan length can be secured in the central part of the fundus, but only a short B-scan length can be applied to the peripheral part of the fundus.

JP 2009-183332 A

Bart Jaeken, Pablo Artal, "Optical Quality of Emmetropic and Myopic Eyes in the Periphery Measured with High-Angular Resolution", Investigative Ophthalmology & Visual Science, June 2012, Vol.53, No.7, pp.3405-3413

An object of the present invention is to improve the efficiency of montage imaging by devising the forms of a plurality of regions to which OCT scanning is applied.

An ophthalmic imaging apparatus according to a first aspect of exemplary embodiments sequentially applies optical coherence tomography (OCT) scans in a predetermined order and under predetermined conditions to a plurality of mutually different regions of the fundus of an eye to be examined. a data collection unit that collects a plurality of data corresponding to the plurality of regions; an image construction unit that constructs an image from each of the plurality of data; a compositing processor for constructing a composite image of the plurality of images. Furthermore, the shape of the first region among the plurality of regions is different from the shape of the second region.

A second aspect of the exemplary embodiment is the ophthalmologic imaging apparatus of the first aspect, including an area setting section that sets the plurality of areas.

A third aspect of the exemplary embodiment is the ophthalmologic imaging apparatus of the second aspect, wherein the data acquisition unit performs a preliminary OCT on the fundus prior to the OCT scanning on the plurality of regions. applying a scan, the image builder building a preliminary image from data collected from the preliminary OCT scan, and the region setting unit analyzing the preliminary image to set the plurality of regions. .

A fourth aspect of exemplary embodiments is the ophthalmologic imaging apparatus according to the third aspect, wherein the area setting unit analyzes the preliminary image to obtain a fundus image area, which is an image area corresponding to the fundus. are specified, and the plurality of areas are set based on the fundus image area.

A fifth aspect of the exemplary embodiment is the ophthalmologic imaging apparatus of the fourth aspect, wherein the area setting section sets the area so that the sum area of the plurality of areas substantially includes the fundus image area. Set multiple regions.

A sixth aspect of the exemplary embodiment is the ophthalmologic imaging apparatus according to the fifth aspect, wherein the plurality of regions have equal depth-direction dimensions, and the region setting unit sets the sum region to the fundus oculi. A dimension of each of the plurality of regions in a direction orthogonal to the depth direction is set so as to substantially include the image region.

A seventh aspect of the exemplary embodiment is the ophthalmologic imaging apparatus of the sixth aspect, wherein a third area of the plurality of areas is located at the center of the fundus, and a fourth area is The dimension of the third region in a direction perpendicular to the depth direction is larger than the dimension of the fourth region in that direction.

An eighth aspect of the exemplary embodiment is the ophthalmologic imaging apparatus of the second aspect, wherein the region setting unit selects the plurality of the Set a region.

A ninth aspect of the exemplary embodiment is the ophthalmologic imaging apparatus of the first aspect, including an order setting unit that sets the order based on the fundus shape.

A tenth aspect of the exemplary embodiment is the ophthalmic imaging apparatus of the ninth aspect, wherein the data acquisition unit performs a preliminary OCT on the fundus prior to the OCT scanning on the plurality of regions. applying a scan, the image builder constructing preliminary images from data collected from the preliminary OCT scans, and the sequencer analyzing the preliminary images to generate shape information of the fundus. and the order is set based on the shape information.

An eleventh aspect of the exemplary embodiments is the ophthalmologic imaging apparatus according to the tenth aspect, wherein the order setting unit obtains a depth position distribution of the fundus as the shape information, The order is set based on

A twelfth aspect of the exemplary embodiments is the ophthalmologic imaging apparatus of the ninth aspect, wherein the order setting unit sets the order based on standard shape information indicating a standard fundus shape generated in advance. set.

A thirteenth aspect of the exemplary embodiment is the ophthalmologic imaging apparatus of the first aspect, including a condition setting unit that sets the condition based on the fundus shape.

A fourteenth aspect of the exemplary embodiment is the ophthalmic imaging apparatus of the thirteenth aspect, wherein for each of the plurality of regions, the data acquisition unit applies a preliminary OCT scan to the region. , the image construction unit constructs a preliminary image of the region from data collected from the region by the preliminary OCT scan, and the condition setting unit analyzes the preliminary image of the region to determine the region is obtained, and based on the depth position, the conditions applied to the OCT scan of the region are set.

A fifteenth aspect of the exemplary embodiment is the ophthalmic imaging apparatus of the thirteenth aspect, wherein prior to the OCT scanning of the plurality of regions, the data acquisition unit performs a preliminary OCT on the fundus. applying a scan, the image construction unit constructing a preliminary image from data collected by the preliminary OCT scan, and the condition setting unit analyzing the preliminary image to generate shape information of the fundus. Then, based on the shape information, conditions to be applied to the OCT scan of each of the plurality of regions are set.

A sixteenth aspect of the exemplary embodiments is the ophthalmologic imaging apparatus according to the fifteenth aspect, wherein the condition setting unit obtains a depth position distribution of the fundus as the shape information, and obtains the depth position distribution conditions applied to the OCT scan of each of the plurality of regions based on the conditions.

A seventeenth aspect of the exemplary embodiments is the ophthalmologic imaging apparatus according to the thirteenth aspect, wherein the condition setting unit performs the plurality of Set the conditions applied to each OCT scan of the region.

An eighteenth aspect of the exemplary embodiments is the ophthalmologic imaging apparatus according to any one of the first to seventeenth aspects, wherein the data acquisition unit receives measurement light projected onto the fundus for the OCT scan. and a reference arm that is the path of the reference light superimposed on the measurement light, wherein the condition indicates at least one of the length of the measurement arm and the length of the reference arm an arm length changing unit that includes a length condition and changes at least one of the length of the measurement arm and the length of the reference arm; and a first control unit that controls the arm length changing unit based on the arm length condition. including.

A nineteenth aspect of the exemplary embodiments is the ophthalmic imaging apparatus of any one of the first to eighteenth aspects, wherein the condition is a path of measurement light projected onto the fundus for the OCT scan. and a focus state changing unit that changes the focus state of the measurement arm, and a second control unit that controls the focus state change unit based on the focus condition. .

A twentieth aspect of the exemplary embodiment is a data collection unit applying an optical coherence tomography (OCT) scan to a fundus of a subject eye to collect data; and processing the data collected by the data collection unit. A method for controlling an ophthalmic imaging apparatus comprising: a processor for performing OCT scanning on a plurality of different regions of the fundus by sequentially applying OCT scans in a predetermined order and under predetermined conditions to the plurality of regions; a data collection step of collecting a plurality of corresponding data; an image construction step of constructing an image from each of the plurality of data; and a composite image of the plurality of images constructed from the plurality of data by the image construction step. and a synthesizing step in which the form of a first area of the plurality of areas is different from the form of the second area.

A twenty-first aspect of the exemplary embodiments is a program that causes a computer to execute the control method of the twentieth aspect.

A twenty-second aspect of the exemplary embodiments is a computer-readable non-transitory recording medium recording the program of the twenty-first aspect.

According to an exemplary embodiment, it is possible to improve the efficiency of montage imaging by devising the shapes of multiple regions to which OCT scanning is applied.

1 is a schematic diagram illustrating an example configuration of an ophthalmic imaging apparatus according to an exemplary embodiment; FIG. 1 is a schematic diagram illustrating an example configuration of an ophthalmic imaging apparatus according to an exemplary embodiment; FIG. 1 is a schematic diagram illustrating an example configuration of an ophthalmic imaging apparatus according to an exemplary embodiment; FIG. 1 is a schematic diagram illustrating an example configuration of an ophthalmic imaging apparatus according to an exemplary embodiment; FIG. FIG. 4 is a schematic diagram for explaining an example of processing executed by an ophthalmologic imaging apparatus according to an exemplary embodiment; FIG. 4 is a schematic diagram for explaining an example of processing executed by an ophthalmologic imaging apparatus according to an exemplary embodiment; FIG. 4 is a schematic diagram for explaining an example of processing executed by an ophthalmologic imaging apparatus according to an exemplary embodiment; FIG. 4 is a schematic diagram for explaining an example of processing executed by an ophthalmologic imaging apparatus according to an exemplary embodiment; FIG. 4 is a schematic diagram for explaining an example of processing executed by an ophthalmologic imaging apparatus according to an exemplary embodiment; 4 is a flow chart representing an example of the operation of an ophthalmic imaging apparatus according to an exemplary embodiment; FIG. 4 is a schematic diagram for explaining an example of the operation of an ophthalmic imaging apparatus according to an exemplary embodiment;

An ophthalmologic imaging apparatus, its control method, program, and recording medium according to exemplary embodiments will be described in detail with reference to the drawings. The disclosure content of the documents cited in this specification and any other known technology can be incorporated into the embodiments. Unless otherwise specified, "image data" and "images" based thereon are not distinguished. Also, unless otherwise specified, the "part" of the subject's eye and its "image" are not distinguished.

An ophthalmic imaging apparatus according to an exemplary embodiment can measure the fundus of a living eye using Fourier-domain OCT (eg, swept-source OCT). The type of OCT applicable to embodiments is not limited to swept source OCT, but may be spectral domain OCT or time domain OCT, for example.

Exemplary embodiments may be capable of processing images acquired by modalities other than OCT. For example, exemplary embodiments may be capable of processing images acquired by any of fundus cameras, SLOs, slit lamp microscopes, and ophthalmic surgical microscopes. An ophthalmic imaging device according to exemplary embodiments may include any of a fundus camera, an SLO, a slit lamp microscope, and an ophthalmic surgical microscope.

Images of a subject eye that can be processed according to exemplary embodiments may include images obtained by analyzing images acquired by any modality. Examples of such an analysis image include a pseudo-colorized image (segmented pseudo-color image, etc.), an image consisting of only a part of the original image (segment image, etc.), and an image obtained by analyzing an OCT image. There are images representing tissue thickness distribution (layer thickness map, layer thickness graph, etc.), images representing tissue shape (curvature map, etc.), and images representing lesion distribution (lesion map, etc.).

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

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

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

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

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. Furthermore, the observation illumination light is once converged near 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 . The observation illumination light is reflected by the periphery of the perforated mirror 21 (area around the perforation), passes through the dichroic mirror 46, is refracted by the objective lens 22, and illuminates the eye E (fundus oculi Ef). do. The return light of the observation illumination light from the subject's eye E is refracted by the objective lens 22, passes through the dichroic mirror 46, passes through the hole formed in the central region of the apertured mirror 21, and passes through the dichroic mirror 55. , through a focusing lens 31 and reflected by a mirror 32 . 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 . The image sensor 35 detects returned light at a predetermined frame rate. The focus (focal position) of the imaging optical system 30 is adjusted so as to match the fundus oculi Ef or the anterior segment of the eye.

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

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

By changing the display position of the fixation target image on the screen of the LCD 39, the fixation position of the subject's eye E by the fixation target can be changed. Examples of fixation positions include a fixation position for acquiring an image centered on the macula, a fixation position for acquiring an image centered on the optic disc, and a position between the macula and the optic disc. There are a fixation position for acquiring a central image and a fixation position for acquiring an image of a site (eyeground periphery) far away from the macula. A graphical user interface (GUI) or the like may be provided for specifying at least one such exemplary fixation position. Further, a GUI or the like for manually moving the fixation position (the display position of the fixation target) can be provided.

The configuration for presenting a fixation target whose fixation position is changeable to the subject's eye E is not limited to a display device such as an LCD. For example, a fixation matrix in which a plurality of light-emitting units (light-emitting diodes, etc.) are arranged in a matrix (array) can be employed instead of the display device. In this case, the fixation position of the subject's eye E by the fixation target can be changed by selectively lighting a plurality of light emitting units. As another example, one or more movable light emitters can generate a 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 examined. Alignment light output from a light-emitting diode (LED) 51 passes through an aperture 52, an aperture 53, and a relay lens 54, is reflected by a dichroic mirror 55, passes through the aperture of the perforated mirror 21, and passes through the dichroic mirror 46. It is transmitted and projected onto the subject's eye E via the objective lens 22 . Return light of the alignment light from the subject's eye E (corneal reflected light, etc.) is guided to the image sensor 35 through the same path as return light of the observation illumination light. Manual alignment or automatic alignment can be performed based on the received light image (alignment index image).

As in the conventional case, the alignment index image of this example consists of two bright spot images whose positions change depending on the alignment state. When the relative positions of the subject's eye E and the optical system change in the xy direction, the two bright spot images are displaced together in the xy direction. When the relative position between the subject's eye E and the optical system changes in the z direction, the relative position (distance) between the two bright spot images changes. When the distance between the subject's eye E and the optical system in the z direction matches the predetermined working distance, the two bright spot images overlap. When the position of the subject's eye E and the position of the optical system match in the xy direction, two bright point images are presented within or near a predetermined alignment target. When the distance between the eye to be examined E and the optical system in the z direction matches the working distance, and the position of the eye to be examined E and the position of the optical system in the xy direction match, the two bright spot images are superimposed for alignment. Presented within the target.

In auto-alignment, the data processing unit 230 detects the positions of the two bright spot images, and the main control unit 211 controls the moving mechanism 150, which will be described later, based on the positional relationship between the two bright spot images and the alignment target. . In manual alignment, the main control unit 211 causes the display unit 241 to display two luminescent spot images together with the observed image of the eye E, and the user operates the operation unit 242 while referring to the two displayed luminescent spot images. to operate the moving mechanism 150 .

The focus optical system 60 generates a split index used for focus adjustment of the eye E to be examined. The focus optical system 60 is moved along the optical path of the illumination optical system 10 (illumination optical path) in conjunction with the movement of the imaging focusing lens 31 along the optical path of the imaging optical system 30 (imaging optical path). The reflecting bar 67 is inserted into and removed from the illumination optical path. When performing focus adjustment, the reflecting surface of the reflecting bar 67 is arranged at an angle in the illumination optical path. Focus light output from the LED 61 passes through a relay lens 62, is split into two light beams by a split index plate 63, passes through a two-hole diaphragm 64, is reflected by a mirror 65, and is reflected by a condenser lens 66 onto a reflecting rod 67. is once imaged on the reflective surface of , and then reflected. Further, the focused light passes through the relay lens 20 , is reflected by the perforated mirror 21 , passes through the dichroic mirror 46 , and is projected onto the subject's eye E via the objective lens 22 . The return light of the focus light from the subject's eye E (reflected light from the fundus, etc.) is guided to the image sensor 35 through the same path as the return light of the alignment light. Manual focusing and autofocusing can be performed based on the received light image (split index image).

Diopter correction lenses 70 and 71 can be selectively inserted in the imaging optical path between the apertured mirror 21 and the dichroic mirror 55 . The dioptric correction lens 70 is a plus lens (convex lens) for correcting high hyperopia. The dioptric correction lens 71 is a minus lens (concave lens) for correcting strong myopia.

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

The retroreflector 41 is movable in directions indicated by arrows in FIG. 1 (incoming and outgoing directions of the measurement light LS). Thereby the length of the measuring arm is changed. The change in measurement arm length is used, for example, to correct the optical path length according to the axial length of the eye and the shape of the fundus, and to adjust the state of interference.

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

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

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

<OCT unit 100>
As illustrated in FIG. 2, the OCT unit 100 is provided with optical systems and mechanisms for applying swept-source OCT. This optical system includes interference optics. This interference optical system divides light from a wavelength tunable light source (wavelength swept light source) into measurement light and reference light, and superimposes the return light of the measurement light from the subject's eye E and the reference light that has passed through the reference light path. Interference light is generated together and the interference light is detected. A detection result (detection signal) obtained by the interference optical system is a signal (interference signal) representing the spectrum of the interference light, and is sent to the arithmetic control unit 200 (image constructing section 220).

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

The reference light LR is guided by the optical fiber 110 to the collimator 111 and converted into a parallel beam, and guided to the retroreflector 114 via the optical path length correction member 112 and the dispersion compensation member 113 . The optical path length correction member 112 is an optical element for matching the optical path length of the reference light LR and the optical path length of the measurement light LS. The dispersion compensation member 113 works together with the dispersion compensation member 42 arranged on the measurement arm 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 beam LR incident on it, thereby changing the length of the reference arm. Changing the reference arm length is used, for example, to correct the optical path length according to the axial length of the eye and the shape of the fundus, and to adjust the state of interference.

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

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

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

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

A clock KC is supplied from the light source unit 101 to the data collection system 130 . 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 wavelength tunable light source. The light source unit 101, for example, splits the light L0 of each output wavelength to generate two split lights, optically delays one of these split lights, combines these split lights, and produces the resulting combined light. A clock KC is generated based on the detection result. The data acquisition system 130 samples the detection signal input from the detector 125 based on the clock KC. Data acquisition system 130 sends the results of this sampling to arithmetic and control unit 200 .

In this example, both an element for changing the measurement arm length (eg retroreflector 41) and an element for changing the reference arm length (eg retroreflector 114 or reference mirror) are provided. but only one element may be provided. Also, 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 may be arbitrary elements (optical members, mechanisms, etc.).

In this way, the swept source OCT splits the light from the wavelength tunable light source into the measurement light and the reference light, and superimposes the return light of the measurement light from the object on the reference light to generate the interference light. In this method, interference light is detected by a photodetector, and an image is formed by applying Fourier transform or the like to detection data collected according to wavelength sweeping and measurement light scanning.

On the other hand, spectral domain OCT divides light from a low coherence light source (broadband light source) into measurement light and reference light, and generates interference light by superimposing the return light of the measurement light from the object on the reference light. , the spectral distribution of the interference light is detected by a spectroscope, and the detected spectral distribution is subjected to Fourier transform or the like to form an image.

That is, the swept-source OCT is an OCT technique that acquires the spectral distribution by time division, and the spectral domain OCT is an OCT technique that acquires the spectral distribution by spatial division.

<Control system/Processing system>
3 and 4 show configuration examples of the control system and the processing system of the ophthalmologic imaging apparatus 1. FIG. The control section 210, the image constructing section 220 and the data processing section 230 are provided in the arithmetic control unit 200, for example. The ophthalmologic imaging apparatus 1 may include a communication device for data communication with an external device. The ophthalmologic imaging apparatus 1 may include a drive device (reader/writer) for reading data from a recording medium and writing data to the recording medium.

<Control unit 210>
The control unit 210 executes various controls. Control unit 210 includes main control unit 211 and storage unit 212 . Further, as shown in FIG. 4, the controller 210 of this embodiment includes a scan controller 213 , a focus controller 214 and an optical path length controller 215 . These are included in the main controller 211 .

<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. 1 to 4). The main control unit 211 is implemented by cooperation between hardware including a processor and control software.

The main control unit 211 can operate any two or all of the scan control unit 213, the focus control unit 214, and the optical path length control unit 215 in a linked (synchronized) manner. As a result, any two or all of the OCT scan, focus adjustment, and optical path length adjustment are coordinated (synchronized).

Under the control of the main control unit 211, the imaging focus driving unit 31A moves the imaging focusing lens 31 arranged in the imaging optical path and the focus optical system 60 arranged in the illumination optical path. A retroreflector (RR) drive unit 41A moves the retroreflector 41 provided on the measurement arm under the control of the main control unit 211 (optical path length control unit 215). The OCT focus drive section 43A moves the OCT focus lens 43 arranged on the measurement arm under the control of the main control section 211 (focus control section 214). The optical scanner 44 provided on the measurement arm operates under the control of the main controller 211 (scan controller 213). A retroreflector (RR) driver 114A moves the retroreflector 114 placed on the reference arm under the control of the main controller 211 (optical path length controller 215). Each of the drive units described above includes an actuator such as a pulse motor that operates under the control of the main control unit 211 .

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

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

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

The control parameters are, for example, parameters used for controlling OCT scanning (scan control parameters), parameters used for focus (focus position, focal length) control (focus control parameters), and either one of the measurement arm and the reference arm. Alternatively, it includes parameters (optical path length control parameters) used for both optical path length controls.

The scan control parameters are parameters that indicate at least the details of control over the optical scanner 44 . The scan control parameters may further include parameters indicating details of control over the light source unit 101 .

Examples of scan control parameters include a parameter that indicates a scan pattern, a parameter that indicates a scan speed, a parameter that indicates a scan interval, and the like. The scan speed is defined, for example, as the A-scan repetition rate. The scan interval is defined, for example, as the interval between adjacent A scans, that is, the interval between scan points.

In this embodiment, montage imaging (OCT scanning) is performed. In this montage imaging, OCT scans are sequentially applied to different regions of the fundus oculi Ef.

Two areas adjacent to each other in the montage shooting may share a part of each other. In other words, for two adjacent regions among the plurality of regions, a portion of one region and a portion of the other region may overlap each other. This overlapping area (common area) is referred to as a margin for determining the relative positions of one area and the other in, for example, a montage (panorama synthesis).

The scan control parameters include parameters related to such montage shooting. Exemplary scan control parameters may include parameters (whole area parameters) indicating attributes of the entire area to which montage imaging is applied.

Other exemplary scan control parameters may include parameters (partial area parameters) that indicate attributes of multiple areas, each of which is part of the overall area.

Still other exemplary scan control parameters may include parameters that indicate attributes of multiple regions that are different from each other without considering the default overall region. In the scan control parameters of this example as well, an area occupied by a plurality of areas is considered to be the entire area, and is called a partial area parameter.

Note that the entire area may be a three-dimensional area, or may be a two-dimensional area when the three-dimensional area is viewed from the front. The same applies to partial areas.

A global area parameter is an arbitrary parameter relating to the area to which montage photography is applied. Examples of overall area parameters include shape parameters, size parameters, and position parameters of the overall area.

The overall area shape parameter is a parameter indicating the shape of the overall area, typically a parameter indicating the shape of the outer edge of the overall area. The outer edge shape of the overall area defined as a two-dimensional area may be, for example, rectangular, circular, elliptical, or arbitrary. The outer edge shape of the entire area defined as a three-dimensional area may be, for example, a rectangular parallelepiped shape, a spherical shape, an ellipsoidal shape, or an arbitrary shape. The outer edge shape of the entire area is, for example, the shape of the outer edge of a planar area defined in the xy plane, the shape of the outer edge of an area (typically a curved surface area) defined on the bowl-shaped fundus surface, or in montage synthesis. It may be the shape of the outer edge of the resulting composite image.

The overall area size parameter is a parameter indicating the size (dimension) of the overall area, and is typically set according to the shape of the overall area. The region size may typically be the outer edge size, area, volume, or any size information of the entire region. The outer edge size of the overall area defined as a two-dimensional area can be, for example, the length of a side, diameter, radius, major axis, minor axis, or perimeter. The outer edge size of the overall area defined as a three-dimensional area may be, for example, the area of the outer surface, the perimeter, the maximum perimeter, or the minimum perimeter. Also, the size of the entire area may be represented by the angle of view.

The entire area position parameter is a parameter indicating the position of the entire area, typically a parameter indicating the position of the representative point in the entire area. The representative point may be, for example, the center of the entire area, the center of gravity, or the vertex. The position of the representative point may include, for example, information indicating the fixation position, information indicating the OCT scan position, or information indicating the part of the fundus.

In one specific example, the overall area parameter is a rectangular area (shape), an area with a length of 20 mm in the x direction and a length of 20 mm in the y direction (size), and the center of which is the macula (center indicates that (position) is matched to the fovea). Another specific example of the overall area parameter is that it is a substantially circular or substantially elliptical region (shape), that it is a region that corresponds to an angle of view of 180 degrees (size), and whose center is the fixation position for macular imaging. corresponds to (position).

The partial area parameters indicate attributes of a plurality of partial areas to which OCT scanning is sequentially applied in montage imaging. A partial area parameter is an arbitrary parameter relating to a plurality of partial areas. Examples of partial area parameters include shape parameters, size parameters, and position parameters of each partial area. These may be the same information as the corresponding global area parameters.

Furthermore, examples of partial area parameters include a parameter indicating the arrangement of a plurality of partial areas and a parameter indicating the order in which OCT scans are applied to the plurality of partial areas.

The focus control parameter is a parameter that indicates the content of control for the OCT focus driving section 43A. Examples of focus control parameters include a parameter indicating the focus position of the measurement arm, a parameter indicating the movement speed of the focus position, a parameter indicating the movement acceleration of the focus position, and the like.

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

The focus control parameter may contain information corresponding to each of the plurality of partial areas. For example, the focus control parameters may include one or more focus positions corresponding to each partial area.

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

The optical path length control parameter is a parameter that indicates the content of control for one or both of the retroreflector driving section 41A and the retroreflector driving section 114A. Examples of optical path length control parameters include a parameter indicating the position of the retroreflector 41, a parameter indicating the moving speed of the retroreflector 41, a parameter indicating the moving acceleration of the retroreflector 41, a parameter indicating the position of the retroreflector 114, and a parameter indicating the position of the retroreflector 114. There are a parameter indicating the movement speed, a parameter indicating the movement acceleration of the retroreflector 114, and the like.

The optical path length control parameter may contain information corresponding to each of the plurality of partial areas. For example, the optical path length control parameters may include one or more retroreflector positions corresponding to each subregion.

When two or more retroreflector positions are associated with one partial area, the optical path length control parameter may include information indicating the range to which each retroreflector position is applied together with these retroreflector positions. The information indicating the applicable range of the retroreflector position is expressed as, for example, information indicating two or more subsets (identification numbers of B-scan lines, etc.) when a plurality of B-scans included in the partial region is taken as a whole set. be.

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

<Focus control unit 214>
The focus control section 214 controls the OCT focus driving section 43A based on the focus control parameters. Details of the processing executed by the focus control unit 214 will be described later. The focus control unit 214 is implemented by cooperation between hardware including a processor and focus control software.

<Optical path length control unit 215>
The optical path length control section 215 controls one or both of the retroreflector driving section 41A and the retroreflector driving section 114A based on the optical path length control parameter. Details of the processing executed by the optical path length control unit 215 will be described later. The optical path length controller 215 is included in the main controller 211 . The optical path length control unit 215 is implemented by cooperation between hardware including a processor and optical path length control software.

As described above, in this embodiment, any two or all of OCT scanning, focus adjustment, and optical path length adjustment are performed in a coordinated (synchronous) manner. Typically, these three operations are performed in tandem. The main control unit 211 realizes linkage between OCT scanning, focus adjustment, and optical path length adjustment according to control software for operating the scan control unit 213, the focus control unit 214, and the optical path length control unit 215 in a coordinated manner. can be done.

<Image constructing unit 220>
The image construction unit 220 includes a processor, and forms OCT image data of the fundus oculi Ef based on the signal (sampling data) input from the data acquisition system 130 . The OCT image data is, for example, B-scan image data (two-dimensional tomographic image data).

Processing to form OCT image data includes noise removal (noise reduction), filtering, fast Fourier transform (FFT), etc., as in conventional Fourier domain OCT. For other types of OCT devices, the image builder 220 performs known processing depending on the type.

The image construction unit 220 forms three-dimensional data of the fundus oculi Ef based on the signal input from the data acquisition system 130 . This three-dimensional data is three-dimensional image data representing a three-dimensional region (volume) of the fundus oculi Ef. The three-dimensional image data means image data in which pixel positions are defined by a three-dimensional coordinate system. Examples of three-dimensional image data include stack data and volume data.

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

Volume data is image data whose pixels are voxels arranged three-dimensionally, and is also called voxel data. Volume data is formed by applying interpolation processing, voxelization processing, etc. to stack data.

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

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

The partial 3D image data projected to construct the shadowgram are set using, for example, segmentation. Segmentation is the process of identifying subregions in an image. Typically, segmentation is used to identify image regions corresponding to predetermined tissues of the fundus oculi Ef. Segmentation is performed by the image construction unit 220 or the data processing unit 230, for example.

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

When OCT angiography is performed, the ophthalmologic imaging apparatus 1 repeatedly scans the same region of the fundus oculi Ef a predetermined number of times. In montage OCT angiography, for example, repeated scans can be applied sequentially in the order indicated by the scan control parameters to a plurality of partial regions in the array indicated by the scan control parameters. In another example, a series of OCT scans in the order indicated by the scan control parameters for multiple partial regions of the array indicated by the scan control parameters can be repeated a predetermined number of times.

Image constructor 220 can construct motion contrast images from the data sets collected by data acquisition system 130 in such repeated scans. This motion contrast image is an angiographic image obtained by emphasizing temporal changes in interference signals caused by blood flow in the fundus oculi Ef. Typically, OCT angiography is applied to a three-dimensional region of the fundus oculi Ef to obtain an image representing the three-dimensional distribution of blood vessels in the fundus oculi Ef.

When OCT angiography is performed, the image constructing unit 220 can construct arbitrary two-dimensional angiographic image data and/or arbitrary pseudo three-dimensional angiographic image data from the three-dimensional angiographic image data. is. For example, the image construction unit 220 can construct two-dimensional angiographic image data representing an arbitrary section of the fundus oculi Ef by applying multi-planar reconstruction to the three-dimensional angiographic image data. In addition, the image construction unit 220 constructs a front image representing a slab of any of the superficial, middle, and deep layers of the retina from the three-dimensional angiographic image data, and constructs a slab of the choroid (such as the choroidal capillary plate). It is possible to construct a frontal image representing

The image construction unit 220 is implemented by cooperation of hardware including a processor and image construction software.

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

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

As illustrated in FIG. 4 , the data processing section 230 of this embodiment includes an area setting section 231 , an order setting section 232 , a condition setting section 233 , a movement detection section 234 and a composition processing section 235 .

<Area setting unit 231>
The region setting unit 231 sets a plurality of regions (a plurality of partial regions) to which montage shooting is applied.

The region setting unit 231 may be configured to set a plurality of partial regions based on the OCT image of the fundus oculi Ef of the eye E to be examined, for example. Typically, the region setting unit 231 analyzes an OCT image constructed from data collected by applying an OCT scan to the fundus oculi Ef to generate shape information of the fundus oculi Ef; and a process of setting a plurality of partial areas based on.

An example of processing that can be executed by the area setting unit 231 will be described with reference to FIGS. 5A and 5B. Reference numeral 300 in FIG. 5A indicates an OCT image (B-scan image) of the fundus oculi Ef. B-scan image 300 was constructed from the data collected by B-scan 320 shown in FIG. 5B.

As can be seen from the B-scan image 300, the fundus shape (fundus surface shape, retinal surface shape, internal limiting membrane shape) is generally a bowl-like shape with a deep central portion and a shallow peripheral portion. Furthermore, there are individual differences in the shape of the fundus. For example, in highly myopic eyes, there is a large difference in depth between the central portion and the peripheral portion, or the shape may be distorted due to posterior staphyloma.

The region setting unit 231 analyzes the B-scan image 300 to obtain shape information indicating the shape of the fundus oculi Ef. Exemplary shape information includes a depth position distribution indicating depth positions (z coordinates) at multiple positions on the fundus oculi Ef.

For example, the region setting unit 231 applies segmentation to the B-scan image 300 to determine an image region corresponding to a predetermined portion of the fundus oculi Ef (for example, the fundus oculi surface, nerve fiber layer, ganglion cell layer, retinal pigment epithelial layer, etc.). A depth position distribution (z-coordinate distribution) of the identified image region can be determined.

Furthermore, the region setting section 231 can set a plurality of partial regions based on the depth position distribution. For example, the region setting unit 231 can specify the depth position corresponding to each of the plurality of partial regions from the depth position distribution, and determine the z-position of each partial region based on the specified depth position. .

In this example, as shown in FIG. 5B, 9 partial areas arranged in 3 rows×3 columns are set. Each of these partial regions is square in the xy plane. Two adjacent partial regions share a boundary with each other (that is, no margin is provided as described above). In this example, the entire area is also square in the xy plane.

On the other hand, in the z-direction, as shown in FIG. 5A, the partial area 311 set at the center of the fundus oculi Ef is arranged on the +z side relative to the partial areas 312 and 313 set at the periphery. In this way, the positions (typically z positions) of a plurality of partial regions are set according to the shape (typically depth position distribution) of the fundus oculi Ef.

Note that in the example shown in FIGS. 5A and 5B , the shape and size of the plurality of partial regions in the xy plane are all the same, but in the present embodiment, partial regions having different shapes and/or sizes from other partial regions are Multiple sub-areas to be included can be set. An example of such a case will be described with reference to FIGS. 6A and 6B.

Reference numeral 400 in FIG. 6A indicates an OCT image (B-scan image) of the fundus oculi Ef. B-scan image 400 was constructed from the data collected by B-scan 420 shown in FIG. 6B.

The region setting unit 231 analyzes the B-scan image 400 and specifies an image region (fundus image region) 401 corresponding to the fundus oculi Ef. The area setting unit 231 can set a plurality of partial areas based on the fundus image area 401 .

For example, the area setting unit 231 can set a plurality of partial areas such that the sum of the partial areas (that is, the entire area) substantially includes the fundus image area 401 .

Here, "substantially" including the fundus image area means, in addition to the case of including the entire fundus image area, for example, the case of including most of the fundus image area, or the case of including the attention area of the fundus image area. This means that the case where a very small part of the fundus image area is not included, such as the case where it is at least included, or the case where a less important part of the fundus image area is not included is allowed.

Also, the "sum area" of a plurality of partial areas means a union set (merged set) when each of the plurality of partial areas is viewed as a set.

In this example, as shown in FIG. 6B, a partial area (central partial area) 411 arranged at the center of the fundus oculi Ef and a partial area (peripheral partial area) 412 arranged around it (peripheral part of the fundus oculi). is set. The central partial region 411 has a square shape in the xy plane. The peripheral partial region 412 has a shape defined by two concentric squares in the xy plane. The outer edge of the central partial area 411 and the inner edge of the peripheral partial area 412 are common (that is, the above-described glue margin is not provided). It should be noted that the entire region of this example is square in the xy plane.

On the other hand, in the z direction, as shown in FIG. 6A, the central partial region 411 is arranged on the +z side of the peripheral partial region 412 . The depth range (length in the depth direction, length in the z direction, A-scan length) of the central partial region 411 is indicated by D, and the dimension in the direction perpendicular to the depth direction (the direction in the xy plane, the lateral direction) is indicated by W1. Similarly, the depth range of the peripheral partial region 412 is D, and the dimension in the direction perpendicular to the depth direction is indicated by W2.

In this example, the A-scan length is constant, and the depth range is D for all partial regions, as in normal OCT. On the other hand, regarding the length of the scan in the horizontal direction (B scan length), under the limitation that the depth range D is constant, the fundus image region 401 is substantially The B-scan length W1 of the central partial region 411 and the B-scan length W2 of the peripheral partial region 412 are set so as to be included in . In this example, the B-scan length W1 of the central partial region 411 is longer than the B-scan length W2 of the peripheral partial region 412 (W1>W2).

Here, the upper limit of the B-scan length may be the maximum B-scan length of the ophthalmologic imaging apparatus 1, or may be a shorter value. Also, the number of partial areas to be set is set as small as possible in order to shorten the time required for montage shooting. It should be noted that it may be possible to select which of the number of partial regions and the coverage rate of the fundus image region is prioritized.

In another example, the region setting unit 231 can analyze the B-scan image 400 to obtain shape information indicating the shape of the fundus oculi Ef. Exemplary shape information includes depth position distribution. The region setting section 231 can set a plurality of partial regions based on the depth position distribution. For example, the region setting unit 231 can specify the depth position corresponding to each of the plurality of partial regions from the depth position distribution, and determine the z-position of each partial region based on the specified depth position. . Also in this example, for example, a central partial area 411 and a peripheral partial area 412 shown in FIG. 6B are set. As shown in FIG. 6A , the central partial area 411 is arranged on the +z side of the peripheral partial area 412 . In this way, the positions (typically z positions) of a plurality of partial regions are set according to the shape (typically depth position distribution) of the fundus oculi Ef.

In some of the examples described above, the B-scan is applied to the fundus oculi Ef to grasp the shape of the fundus oculi Ef (rough shape, detailed shape), and a plurality of partial regions are set from the grasped shape of the fundus oculi Ef. The OCT scan mode (scan pattern) for grasping the shape of the fundus oculi Ef is not limited to B scan, and any OCT scan mode capable of recognizing the fundus shape (typically, fundus image area or depth position distribution) Just do it. Examples of such OCT scan modes include radial scan, cross-scan, multi-line scan, multi-cross-scan, raster scan, and spiral scan.

In some of the examples described above, a plurality of partial regions for montage photography are set based on OCT images obtained by actually applying OCT scanning to the fundus Ef of the eye E to be examined. , may be configured to set a plurality of partial regions for montage photography based on a standard fundus shape.

In this case, standard shape information indicating a standard fundus shape obtained from clinical data, a model eye, or an eyeball model is generated and stored in the storage unit 212 . The region setting unit 231 can set a plurality of partial regions based on the standard shape information in the same manner as when based on the OCT image of the fundus oculi Ef. Typically, the standard shape information includes a standard depth position distribution in the fundus, and the region setting section 231 can set a plurality of partial regions based on this depth position distribution.

Two or more pieces of standard shape information can be prepared and selectively used. For example, standard shape information corresponding to normal eyes and standard shape information corresponding to highly myopic eyes can be prepared. Considering that the shape of the eyeball (posterior pole) exhibits various forms in severely myopic eyes, it is possible to prepare a plurality of standard shape information according to a predetermined posterior eyeball shape classification.

When two or more pieces of standard shape information are prepared, the ophthalmologic photographing apparatus 1 receives information indicating the fundus shape of the eye E to be examined. For example, the ophthalmologic photographing apparatus 1 can receive fundus shape information of the subject's eye E from a server, computer, or recording medium using the above-described communication device or drive device. Fundus shape information is typically included in medical data such as electronic charts, interpretation reports, and summaries.

Alternatively, the ophthalmologic imaging apparatus 1 can cause the display unit 241 to display a screen presenting a plurality of fundus shape options. In this case, the user can use the operation unit 242 to select an option corresponding to the eyeball shape of the eye E to be examined from a plurality of options.

The region setting section 231 can set a plurality of partial regions for montage photography based on standard shape information selected from two or more pieces of standard shape information.

The area setting unit 231 is implemented by cooperation between hardware including a processor and area setting software.

<Order setting unit 232>
The order setting unit 232 sets the order of applying OCT scanning to a plurality of partial regions for montage imaging according to the fundus shape of the eye E to be examined.

For example, the order setting unit 232 may be configured to set a plurality of partial regions based on the OCT image of the fundus oculi Ef of the eye E to be examined. Typically, the order setting unit 232 analyzes an OCT image constructed from data collected by applying an OCT scan to the fundus oculi Ef to generate shape information of the fundus oculi Ef; and setting the application order of the OCT scans for the plurality of partial regions based on.

Typically, the order setting unit 232 is configured to obtain the depth position distribution of the fundus oculi Ef as the shape information, and set the OCT scan application order based on this depth position distribution.

Generation of shape information can be executed in the same way as the area setting unit 231 . If the area setting section 231 has already generated shape information, the order setting section 232 can use the shape information generated by the area setting section 231 . Conversely, if the order setting unit 232 has already generated shape information, the region setting unit 231 can use the shape information generated by the order setting unit 232 .

As a specific example, when the region setting unit 231 sets nine partial regions shown in FIGS. , for example, the order shown in FIG. 7 is set. More specifically, the order setting unit 232 selects the upper left partial area for the eight partial areas arranged around the center partial area among the nine partial areas arranged in 3 rows×3 columns. 1st to 8th in order counterclockwise from , to the upper central partial area, and further, the 9th order is given to the central partial area.

This ordering is done according to the fundus shape. In this example, the order setting unit 232 first selects the 9 partial areas based on the depth position distribution, the central partial area arranged at the deepest position (most +z side), and the other 8 partial areas. categorized into partial areas. Furthermore, the order setting unit 232 assigns the ninth order to the central partial area, and assigns the first to eighth orders to the eight peripheral partial areas.

Here, the first order may be assigned to the central partial area, and the second to ninth orders may be assigned to the eight peripheral partial areas.

Also, the order in which the eight peripheral partial areas are set is not limited to the example in FIG. For example, an order can be given to these partial regions according to a predetermined orientation. Alternatively, the depth position (z coordinate) of each of these partial areas may be obtained, and the order may be given to these partial areas in descending or ascending order of z coordinate.

As another specific example, when the two partial areas shown in FIGS. 6A and 6B are set by the area setting unit 231, the order setting unit 232 can arbitrarily assign an order to the two partial areas. can.

In some of the examples described above, the order of applying OCT scans to a plurality of partial regions for montage photography is set based on OCT images obtained by actually applying OCT scans to the fundus Ef of the eye E to be examined. , the order setting unit 232 may be configured to set the OCT scan application order based on a standard fundus shape. In this case, the same standard shape information as in setting a plurality of partial areas can be used. Also, two or more pieces of standard shape information can be prepared and selectively used.

The order setting unit 232 is implemented by cooperation between hardware including a processor and order setting software.

<Condition setting unit 233>
The condition setting unit 233 sets conditions for applying OCT scanning to a plurality of partial regions for montage imaging according to the fundus shape of the eye E to be examined. The conditions set by the condition setting unit 233 may include any of the aforementioned control parameters (scan control parameters, focus control parameters, optical path length control parameters).

For example, for each of a plurality of partial regions for montage imaging, the condition setting unit 233 analyzes the OCT image obtained by applying the preliminary OCT scan to the partial region, and determines the depth of the fundus oculi Ef in the partial region. A depth position may be obtained, and based on this depth position, a condition to be applied to the partial region in montage photography may be set.

Instead of individually applying preliminary OCT scans to a plurality of partial regions, a preliminary OCT scan is performed to determine the shape of the region of the fundus oculi Ef corresponding to the entirety of the plurality of partial regions (entire region). may be applied to set conditions for a plurality of partial regions from the image obtained thereby.

The condition setting unit 233 is configured to obtain the depth position distribution of the fundus oculi Ef as the shape information, and to set the conditions applied to the OCT scans of each of the plurality of partial regions based on the depth position distribution. good.

Generation of shape information can be executed in the same way as the area setting unit 231 or the order setting unit 232 . If the region setting unit 231 or the order setting unit 232 has already generated shape information, the condition setting unit 233 can use the shape information generated by the region setting unit 231 or the order setting unit 232 . Conversely, if the condition setting section 233 has already generated shape information, the area setting section 231 or the order setting section 232 can use the shape information generated by the condition setting section 233 .

As a specific example, when setting the optical path length control parameter based on the depth position distribution, the condition setting unit 233 determines the depth position of each of a plurality of partial regions from the depth position distribution. Then, one or both of the position of the retroreflector 41 and the position of the retroreflector 114 corresponding to the determined depth position can be obtained. The retroreflector position thus determined is applied when the partial region is OCT-scanned in montage imaging. That is, when the partial area is OCT-scanned in montage imaging, the optical path length control unit 215 controls either one of the retroreflector driving unit 41A and the retroreflector driving unit 114A or control both sides.

As another specific example, when setting the focus control parameters based on the depth position distribution, the condition setting unit 233 determines the depth position of each of a plurality of partial regions from the depth position distribution. and the position of the OCT focusing lens 43 corresponding to the determined depth position can be determined. The position of the OCT focusing lens 43 obtained in this manner is applied when the partial region is OCT-scanned in montage imaging. That is, when OCT scanning the partial region in montage photography, the focus control unit 214 controls the OCT focus driving unit 43A so that the OCT focus lens 43 is arranged at the obtained position.

The condition setting unit 233 is implemented by cooperation of hardware including a processor and condition setting software.

<Movement detector 234>
The ophthalmologic photographing apparatus 1 includes a fundus camera unit 2 that repeatedly photographs the subject's eye E to obtain time-series images. The time-series images acquired by the fundus camera unit 2 are, for example, the observation images described above.

The movement detection unit 234 analyzes the observed image acquired by the fundus camera unit 2 and detects movement of the eye E to be examined. For example, the movement detection unit 234 analyzes each image included in the observation image, detects feature points, and obtains time-series changes in the positions of the feature points. The feature points may be, for example, the center/center of gravity/outline of the pupil, the center/center of gravity/outline of the iris, and the like.

The scan controller 213 can control the optical scanner 44 based on the output from the movement detector 234 while controlling the optical scanner 44 and the OCT unit 100 according to the scan control parameters. Control of the optical scanner 44 based on the output from the movement detection section 234 is so-called tracking control.

Tracking is performed by the following series of processes disclosed in Japanese Unexamined Patent Application Publication No. 2017-153543, for example. First, the movement detection section 234 registers any frame (front image) of the observation image acquired by the retinal camera unit 2 as a reference image.

Furthermore, the movement detection unit 234 obtains changes in the positions of the feature points in the other frames with respect to the positions of the feature points in the reference image. This corresponds to finding the time-series change in the positions of the feature points, that is, finding the displacement between the reference image and the other frames. Note that when the displacement exceeds the threshold value due to blinking or fixation dislocation, or when displacement detection becomes impossible, the movement detection unit 234 can register the subsequently acquired frame as a new reference image. . Also, the method of obtaining the time-series change in the position of the feature point is not limited to this, and for example, the displacement of the feature point between two consecutive frames may be obtained sequentially.

The movement detection unit 234 sends control information for canceling this time-series change to the scan control unit 213 each time a time-series change in the position of the feature point is obtained. The scan control unit 213 corrects the orientation of the optical scanner 44 based on the control information that is sequentially input.

The movement detection unit 234 is implemented by cooperation of hardware including a processor and movement detection software.

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

When adjacent OCT images have margins, the composition processing unit 235 determines the relative positions between the two OCT images so that the positions of the images rendered in the margins match each other. can be done.

If the margin is not provided, the composition processing unit 235 determines the arrangement of the plurality of OCT images corresponding to the plurality of partial regions according to the arrangement of the plurality of partial regions set by the region setting unit 231, for example. can be done.

<User Interface 240>
User interface 240 includes display unit 241 and operation unit 242 . Display unit 241 includes 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, that combines a display function and an operation function. It is also possible to construct embodiments that do not include at least a portion of user interface 240 . For example, the display device may be an external device connected to the ophthalmic imaging equipment.

<motion>
The operation of the ophthalmologic imaging apparatus 1 will be described. It is assumed that preparatory processing similar to the conventional one, such as patient ID input, fixation target presentation, fixation position adjustment, alignment, focus adjustment, and OCT optical path length adjustment, has already been performed.

An example of the operation of the ophthalmologic photographing apparatus 1 will be described with reference to FIG.

(S1: Apply a preliminary OCT scan to the fundus to obtain a preliminary image)
First, the ophthalmologic imaging apparatus 1 uses the optical scanner 44 and the OCT unit 100 to apply a preliminary OCT scan to the fundus oculi Ef. Image builder 220 builds a preliminary image from the data collected from the preliminary OCT scan. The preliminary images are sent to the area setting section 231 , the order setting section 232 and the condition setting section 233 .

Note that the scan density of the preliminary OCT scan may be the same as the scan density of the montage imaging, or may be lower than the scan density of the montage imaging. A preliminary image can also be any data constructed from data acquired by a preliminary OCT scan, typically data obtained by applying a Fourier transform to the acquired data (reflection intensity profile ), or data (image data or image) obtained by applying an imaging process (including pixel value assignment) to the reflection intensity profile.

(S2: Set multiple partial areas, scan order, and scan conditions)
The region setting unit 231 sets a plurality of partial regions for montage photography based on the preliminary image obtained in step S1. In this example, it is assumed that two partial areas (central partial area 411 and peripheral partial area 412) shown in FIGS. 6A and 6B are set. Information indicating the set partial areas is stored in the storage unit 212 .

The order setting unit 232 sets the order of OCT scanning for the plurality of partial regions set by the region setting unit 231 based on the preliminary image obtained in step S1. In this example, scan orders are assigned to the central partial area 411 and the peripheral partial area 412 shown in FIGS. 6A and 6B.

When the number of partial areas is two as in this example, any one can be set as the first and the other as the second. In this example, OCT scanning is applied to the central partial region 411 first and to the peripheral partial region 412 later.

In general, the scanning order of multiple partial regions for montage photography is typically set based on the fundus shape (depth position distribution, etc.), but the arrangement of multiple partial regions may be additionally considered. It is possible. Therefore, it is not necessary to continuously scan two or more partial areas at equivalent depth positions. Scanning may be performed, followed by scanning of other partial areas of the two or more partial areas. Information indicating the set scan order is stored in the storage unit 212 .

The condition setting unit 233 sets conditions to be applied in OCT scanning for each of the plurality of partial regions set by the region setting unit 231, based on the preliminary image obtained in step S1. In this example, at least an optical path length control parameter and a focus control parameter are set for each of the central partial area 411 and the peripheral partial area 412 . The set scan conditions are saved in the storage unit 212 .

(S3: Start montage shooting)
After completing step S2, the ophthalmologic imaging apparatus 1 starts montage imaging. The ophthalmologic imaging apparatus 1 starts montage imaging in response to a predetermined imaging trigger. The shooting trigger is, for example, a signal indicating the end of step S2 or a signal indicating a user's instruction.

Upon receiving the imaging trigger, the main controller 211 applies light for applying an OCT scan to the central partial region 411, which is the first partial region among the central partial region 411 and the peripheral partial region 412 set in step S2. It controls the scanner 44 or the LCD 39 (fixation position). This processing is executed by the scan control unit 213 .

(S4: Execute scan condition control)
The optical path length control unit 215 controls one or both of the retroreflector driving unit 41A and the retroreflector driving unit 114A based on the optical path length control parameter set in step S2, thereby adjusting the optical path length of the interference optical system. The optical path length is set according to the depth position of the partial area.

Further, the focus control unit 214 controls the OCT focus driving unit 43A based on the focus control parameters set in step S2, thereby adjusting the focus state (focus position, focal length) of the measurement arm of the interference optical system to the relevant part. The optical path length is set according to the depth position of the area.

In addition to these, adjustment of the polarization controller 118, adjustment of the polarization controller 103, adjustment of the attenuator 120, and the like may be performed. The adjustment of the polarization controller 118 is for optimizing the interference efficiency/interference intensity between the measurement light LS and the reference light LR. It is done by feedback control. Adjustment of the polarization controller 103 and adjustment of the attenuator 120 are the same.

(S5: Apply OCT scan to partial area)
The scan control unit 213 applies OCT scanning to the partial region based on the scan control parameters set in step S2.

(S6: Has the entire partial area been scanned?)
When the OCT scan has been applied to all of the partial areas set in step S2 (S6: Yes), the process proceeds to step S8. In this example, when the OCT scanning is applied to both the central partial region 411 and the peripheral partial region 412, that is, when the OCT scanning of the peripheral partial region 412 is finished considering the scanning order, the process proceeds to step S8.

On the other hand, if OCT scanning has not yet been applied to any of the partial regions set in step S2 (S6: No), the process proceeds to step 7. In this example, considering the order of scanning, when the OCT scanning of the central partial region 411 is completed, the process proceeds to step S7.

(S7: Move to next partial area)
If it is determined in step S6 that there is a partial region to which OCT scanning has not been applied yet (S6: No), the scan control unit 213 applies OCT scanning next based on the scanning order set in step S2. specify the subregion to be Furthermore, the scan control unit 213 controls the optical scanner 44 or the LCD 39 (fixation position) for applying OCT scanning to the specified next partial region. Then, the process returns to step S4.

By repeatedly executing steps S4 to S7 until "Yes" is determined in step S6, scanning conditions ( optical path length, focus state, polarization state, etc.), it is possible to apply the OCT scan according to the order according to the depth position of these partial regions.

(S8: Construct an image of each partial area)
When the OCT scan has been applied to all of the partial areas set in step S2 (S6: Yes), the process proceeds to step S8.

In step S8, for each of the plurality of partial regions set in step S2, the image constructing unit 220 constructs an OCT image from the data acquired by the OCT scanning of the partial region.

In this example, typically, as shown in FIG. 9, raster scanning is applied to the central partial region 411 to construct a three-dimensional image corresponding to the central partial region 411 . It is assumed that the length of the B-scan that constitutes the raster scan for the central partial region 411 is the maximum B-scan length of the ophthalmologic imaging apparatus 1 . For the peripheral partial area 412 , the B-scans of the arrangement shown in FIG. 9 are applied to construct a three-dimensional image corresponding to the peripheral partial area 412 . In this way, a plurality of three-dimensional images corresponding to the plurality of partial areas set in step S2 are obtained.

(S9: construct composite image)
The synthesizing unit 235 synthesizes a plurality of three-dimensional images corresponding to the plurality of partial areas constructed in step S8, thereby constructing a synthesized image corresponding to the sum area (whole area) of the plurality of partial areas ( end).

The data processor 230 can render the composite image constructed by the composite processor 235 . The main control unit 211 can cause the display unit 241 to display an image constructed by rendering.

In the operation example shown in FIG. 8, a series of processes including a preliminary OCT scan, construction of a preliminary image, generation of shape information of the fundus oculi Ef, and setting of scan conditions for a plurality of partial regions for montage photography are performed as follows: It is done before the montage shooting.

On the other hand, this series of processing may be executed while performing montage photography. For example, for each partial region, a series of processes including preliminary OCT scanning, construction of a preliminary image, generation of shape information of the fundus oculi Ef, and setting of scanning conditions for the partial region may be performed. In this example, every time the partial region is switched, a preliminary OCT scan for the new partial region, construction of a preliminary image of the new partial region, generation of shape information of the region of the fundus oculi Ef corresponding to the new partial region, and After setting the scan conditions for the new partial area, the OCT scan for montage imaging is applied to the new partial area, and after the OCT scan is completed, the next partial area is processed. A series of such processes are sequentially performed on a plurality of partial regions in an order according to the fundus shape.

〈Action and effect〉
Some actions and some effects of exemplary embodiments will be described.

An ophthalmic imaging device (1) according to an exemplary embodiment includes a data acquisition unit, an image construction unit, and a composition processing unit.

The data acquisition unit sequentially applies an optical coherence tomography (OCT) scan in a predetermined order and under predetermined conditions to a plurality of mutually different regions (a plurality of partial regions) of the fundus (Ef) of the eye (E) to be examined. By doing so, a plurality of data corresponding to a plurality of partial areas are collected.

In the above example, the data acquisition part includes the OCT unit 100 and the elements in the fundus camera unit 2 that make up the measurement arm (retroreflector 41, OCT focusing lens 43, optical scanner 44, objective lens 22, etc.). .

The data acquisition unit in the above example sequentially applies OCT scans in a predetermined order and under predetermined conditions (optical path length, focus state, polarization state) to a plurality of different partial regions of the fundus oculi (Ef). , collect a plurality of data corresponding to a plurality of partial regions. Here, the process of switching the target of OCT scanning from a certain partial area to the next partial area is performed by either one or both of control of the optical scanner 44 and control of the LCD 39 (fixation target).

The image constructing section constructs an image from each of the plurality of data collected corresponding to the plurality of partial areas by the data collecting section. In the example above, the image constructor includes image constructor 220 .

The synthesizing section constructs a composite image of the plurality of images constructed from the plurality of data by the image constructing section. In the above example, the composition processing section includes composition processing section 235 .

Furthermore, the form of the first area among the plurality of partial areas to which the OCT scan is applied is different from the form of the second area. The form of the partial region includes, for example, one or both of shape and size (dimensions).

For example, in the example shown in FIGS. 6A and 6B, the shape of the central partial region 411 (the shape in the xy plane) is a region whose outer edge is defined by a square, and the shape of the peripheral partial region 412 (the shape in the xy plane) is , the area defined by the outer and inner edges by two squares concentric with each other and of different dimensions. Here, the outer edge of the central partial region 411 and the inner edge of the peripheral partial region 412 are common. Therefore, the two subregions in the example shown in FIGS. 6A and 6B differ from each other both in shape and size.

Note that the dimension may be defined arbitrarily. Typically, it may be defined in a B-scan image as shown in FIG. 6A, or may be defined in the xy plane as shown in FIG. 6B, and illustration is omitted. may be defined in a three-dimensional domain (xyz space). Also, the dimensions may be one-dimensional, two-dimensional, or three-dimensional.

According to such an exemplary embodiment, it is possible to apply partial regions of a desired form (shape, size) instead of conventionally performing montage photography using partial regions of a uniform form. Therefore, the efficiency of montage shooting can be improved.

An ophthalmic imaging apparatus according to an exemplary embodiment may include an area setting unit that sets multiple areas to which montage imaging is applied. In the above example, the area setting section includes the area setting section 231 .

By providing such an area setting unit, it becomes possible to set a plurality of areas to be subjected to montage imaging by the ophthalmologic imaging apparatus itself.

In an exemplary embodiment, the data collector may apply a preliminary OCT scan to the fundus of the subject's eye prior to the OCT scan (montage) of multiple regions. Additionally, the image builder may construct a preliminary image from the data collected from this preliminary OCT scan. In addition, the area setting section may be configured to set a plurality of areas for montage photography by analyzing the preliminary image.

In the above example, as shown in FIGS. 6A and 6B, the ophthalmologic imaging apparatus 1 constructs a B-scan image 400 by applying a B-scan 420 to the fundus oculi Ef of the subject's eye E before montage imaging. By analyzing the B-scan image 400, a central partial area 411 and a peripheral partial area 412 can be set.

According to such an exemplary embodiment, acquisition of an OCT image of the fundus of the subject's eye, setting of a plurality of regions based on the fundus OCT image, and montage photography for the set plurality of regions are performed by way of example. can be performed only by the ophthalmic imaging apparatus according to the preferred embodiment.

In an exemplary embodiment, the area setting unit identifies a fundus image area, which is an image area corresponding to the fundus of the subject's eye, by analyzing the preliminary image, and performs montage imaging based on the identified fundus image area. may be configured to set a plurality of areas for

In the above example, as shown in FIGS. 6A and 6B, the ophthalmologic imaging apparatus 1 identifies the fundus image region 401 by analyzing the B-scan image 400, and based on the fundus image region 401, the center partial region 411 and the A peripheral subregion 412 can be set.

According to such an exemplary embodiment, it is possible to appropriately set a plurality of areas for montage photography based on the morphology (shape, size, etc.) of the fundus obtained from the fundus image area.

In an exemplary embodiment, the region setting unit is configured to set the plurality of regions such that a sum region (whole region) of the plurality of regions for montage photography substantially includes the fundus image region. you can

In the above example, as shown in FIGS. 6A and 6B, the ophthalmologic imaging apparatus 1 adjusts the central partial region 411 and the central partial region 411 and the peripheral partial region 412 so that the sum of the central partial region 411 and the peripheral partial region 412 substantially includes the fundus image region 401 . A peripheral subregion 412 can be set.

According to such an exemplary embodiment, it is possible to appropriately set a plurality of regions for montage photography so as to reliably obtain a wide-range synthetic image of the fundus of the subject's eye.

In an exemplary embodiment, the depth-direction (z-direction) dimensions of the multiple regions for montage photography may be equal to each other. Furthermore, the region setting unit sets the direction (xy direction).

In the above example, as shown in FIGS. 6A and 6B, the depth dimension D of the central partial region 411 and the depth dimension D of the peripheral partial region 412 are equal to each other. Further, the ophthalmologic imaging apparatus 1 moves the center partial region 411 in a direction perpendicular to the depth direction (xy direction) so that the sum of the central partial region 411 and the peripheral partial region 412 substantially includes the fundus image region 401 . and a dimension W2 in the direction (xy direction) perpendicular to the depth direction of the peripheral partial region 412 can be set.

According to such an exemplary embodiment, it is possible to appropriately set a plurality of regions for montage imaging using a normal ophthalmologic imaging apparatus (especially a fundus OCT apparatus) with a constant A-scan length. is.

In an exemplary embodiment, the third area of the plurality of areas for montage photography may be arranged at the center of the fundus of the subject's eye, and the fourth area may be arranged at the periphery of the fundus. Furthermore, the dimension of the third region in the direction (xy direction) perpendicular to the depth direction (z direction) is larger than the dimension of the fourth region in the direction (xy direction).

In the above example, the central partial area 411 is arranged at the center of the fundus of the subject's eye, and the peripheral partial area 412 is arranged at the peripheral part of the fundus. Furthermore, the dimension W1 of the central partial region 411 in the direction (xy direction) orthogonal to the depth direction (z direction) is larger than the dimension W2 of the peripheral partial region 412 in the direction (xy direction) (W1> W2).

According to such an exemplary embodiment, it is possible to appropriately set a plurality of regions for montage photography according to the shape of the fundus.

In an exemplary embodiment, the region setting unit may be configured to set a plurality of regions for montage photography based on standard shape information indicating a standard fundus shape generated in advance.

According to such an exemplary embodiment, when the fundus shape of the subject's eye cannot be measured or the measurement result cannot be obtained, a plurality of regions for montage photography are set using a standard fundus shape. it becomes possible to

Further, according to the exemplary embodiment described above, OCT scanning can be applied to a plurality of regions of the fundus in an order and under conditions according to the shape of the fundus. By setting both the scanning order and the scanning conditions according to the shape of the fundus in this way, the switching of the scanning conditions accompanying the switching of the regions to which the OCT scanning is applied will not wastefully prolong the time required for the montage imaging. disappears.

For example, in the prior art, changing conditions (focus adjustment, optical path length adjustment, etc.) involving movement of an optical element by an actuator takes longer than the operation of an optical scanner, so switching regions cannot be performed at high speed.

On the other hand, in the exemplary embodiment, for example, while gradually moving the optical path length and the focus position from the deep side to the shallow side of the fundus, the scan area is moved from the deep point to the shallow point of the fundus. be able to.

As a result, the amount of change in scanning conditions (change amount of optical path length, amount of movement of focus position, etc.) associated with switching the scan area is reduced, so the time required to change the scanning conditions is shorter than before. The time required for montage shooting is shorter than before. That is, it is possible to shorten the time required for montage photography while changing the scanning conditions appropriately and at high speed for improving the image quality. Therefore, the exemplary embodiment contributes to both shortening the time required for montage shooting and improving image quality.

An ophthalmologic imaging apparatus according to an exemplary embodiment includes an order setting unit that sets a scan order according to a fundus shape. In the example above, the order setter includes the order setter 232 .

By providing such an order setting unit, the scan order can be set by the ophthalmologic imaging apparatus itself. As a result, the setting of the scan order and the montage photography according to the scan order can be performed only by the ophthalmic imaging apparatus according to the exemplary embodiment.

In an exemplary embodiment, the data collector may apply a preliminary OCT scan to the fundus prior to the OCT scans (montage) to multiple regions of the fundus. Additionally, the image builder may construct a preliminary image from the data collected from this preliminary OCT scan. In addition, the order setting unit may be configured to generate shape information of the fundus of the subject's eye by analyzing this preliminary image, and set the scan order based on this shape information.

According to such an exemplary embodiment, the measurement of the fundus shape of the subject's eye, the setting of the scan order based on the measurement result of the fundus shape, and the montage shooting according to the scan order are performed in the exemplary embodiment. can be performed only with the ophthalmic imaging apparatus according to

In an exemplary embodiment, the order setting unit may be configured to obtain the depth position distribution of the fundus of the subject's eye as shape information, and set the scan order based on this depth position distribution.

According to such an exemplary embodiment, the depth position distribution of the fundus of the subject's eye can be used to appropriately set the scan order of the plurality of regions in accordance with the depth position.

In an exemplary embodiment, the order setting unit may be configured to set the scan order based on standard shape information indicating a standard fundus shape generated in advance.

According to such an exemplary embodiment, it is possible to set scan conditions using a standard fundus shape when the fundus shape of the subject's eye cannot be measured or the measurement results cannot be obtained. .

An ophthalmologic imaging apparatus according to an exemplary embodiment may include a condition setting unit that sets scan conditions according to the fundus shape. In the above example, the condition setting section includes the condition setting section 233 .

By providing such a condition setting unit, it is possible to set the scan conditions by the ophthalmologic imaging apparatus itself.

In an exemplary embodiment, for each region of a plurality of regions for montage imaging, the data collector may apply a preliminary OCT scan to that region. Further, the image builder may construct a preliminary image of the region from data collected from the region from this preliminary OCT scan. In addition, the condition setting unit obtains the depth position of the fundus in the region by analyzing the preliminary image of the region, and sets the scan conditions applied to the OCT scan of the region based on the depth position. may be configured to

Alternatively, in an exemplary embodiment, the data acquisition unit may apply a preliminary OCT scan to the fundus of the subject's eye prior to the OCT scans for multiple regions for montage imaging. Additionally, the image builder may construct a preliminary image from the data collected from this preliminary OCT scan. In addition, the condition setting unit analyzes the preliminary image to generate shape information of the fundus of the subject's eye, and sets scan conditions applied to OCT scans of each of the plurality of regions based on the shape information. may be configured to

According to such an exemplary embodiment, the measurement of the fundus shape of the subject's eye, the setting of the scan conditions based on the measurement result of the fundus shape, and the montage photography based on the set scan conditions are performed as an example. It can be performed only with the ophthalmic imaging apparatus according to the embodiment.

In an exemplary embodiment, the condition setting unit obtains the depth position distribution of the fundus of the eye to be inspected as shape information, and sets scan conditions to be applied to OCT scans of each of the plurality of regions based on the depth position distribution. may be configured to set

According to such an exemplary embodiment, it is possible to appropriately set scanning conditions such as the optical path length and the focal position using the depth position distribution of the fundus of the subject's eye.

In an exemplary embodiment, the condition setting unit sets scan conditions to be applied to OCT scans of each of the plurality of regions for montage imaging, based on standard shape information indicating a standard fundus shape that has been generated in advance. may be configured to set

According to such an exemplary embodiment, when the fundus shape of the subject's eye cannot be measured or the measurement result cannot be obtained, the scan conditions for montage photography are set using the standard fundus shape. becomes possible.

In an exemplary embodiment, the data acquisition unit includes a measurement arm, which is the path of measurement light projected onto the fundus of the eye to be examined for OCT scanning, and a reference arm, which is the path of reference light superimposed on the measurement light. may contain Further, the scan conditions may include arm length conditions that indicate at least one of the length of the measurement arm and the length of the reference arm.

Additionally, an ophthalmic imaging apparatus according to an exemplary embodiment may include an arm length changing section and a first control section.

The arm length changing section changes at least one of the length of the measurement arm and the length of the reference arm. In the above example, the arm length changing section includes either one or both of the combination of the retroreflector 41 and the retroreflector drive section 41A and the combination of the retroreflector 114 and the retroreflector drive section 114A.

The first controller controls the arm length changer based on the arm length condition. In the example above, the first controller includes the optical path length controller 215 .

According to such an exemplary embodiment, it is possible to perform OCT optical path length adjustment according to the shape of the fundus in montage imaging in an order according to the shape of the fundus, thereby improving image quality.

In an exemplary embodiment, the scan conditions include focus conditions indicating the focus state (focus position, focal length) of the measurement arm, which is the path of the measurement light projected onto the fundus of the eye to be examined for OCT scanning. good.

Additionally, an ophthalmic imaging apparatus according to an exemplary embodiment may include a focus state changing section and a second control section.

The focus state changing section changes the focus state of the measurement arm. In the above example, the focus state changer includes the OCT focus lens 43 and the OCT focus driver 43A.

The second controller controls the focus state changer based on the focus condition. In the above example, the second control includes focus control 214 .

According to such an exemplary embodiment, it is possible to perform OCT focus adjustment according to the shape of the fundus in montage imaging in an order according to the shape of the fundus, and to improve image quality.

Exemplary embodiments provide a method of controlling an ophthalmic imaging device. An ophthalmologic imaging apparatus to which this control method is applied includes a data collection unit that collects data by applying an OCT scan to the fundus of an eye to be examined, and a processor that processes the data collected by the data collection unit. In the above example, the data acquisition part includes the OCT unit 100 and the elements in the fundus camera unit 2 that make up the measurement arm (retroreflector 41, OCT focusing lens 43, optical scanner 44, objective lens 22, etc.). . Also, in the above example, the processor includes an image construction unit 220 and a data processing unit 230 (at least a composition processing unit 235).

The control method includes a data collection step, an image construction step, and a composition step. The data collection step collects a plurality of data corresponding to the plurality of regions by sequentially applying an OCT scan in a predetermined order and under predetermined conditions to a plurality of mutually different regions of the fundus of the subject's eye. Here, the form of the first area among the plurality of areas is different from the form of the second area. The image construction step constructs an image from each of the plurality of collected data. The synthesizing step constructs a composite image of the plurality of images constructed from the plurality of data by the image constructing step.

Any of the items described in the exemplary embodiments can be combined with such a method of controlling an ophthalmic imaging apparatus.

An exemplary embodiment provides a program that causes a computer to execute such a method of controlling an ophthalmic imaging apparatus. Any of the items described in the exemplary embodiments can be combined for this program.

Also, it is possible to create a computer-readable non-transitory recording medium recording such a program. Any of the items described in the exemplary embodiments can be combined for this recording medium. Also, this non-temporary recording medium may be in any form, such as a magnetic disk, an optical disk, a magneto-optical disk, and a semiconductor memory.

According to the method, program, or recording medium according to the exemplary embodiments, it is possible to improve the efficiency of montage imaging by devising the forms of multiple regions to which OCT scanning is applied. In addition, actions and effects are achieved according to items combined with the method, program, or recording medium according to the exemplary embodiments.

The configurations described above are merely examples of embodiments of the present invention. Therefore, any modification (omission, substitution, addition, etc.) within the scope of the present invention is possible.

1 ophthalmic photographing apparatus 41 retroreflector 41A retroreflector driving unit 43 OCT focusing lens 43A OCT focusing driving unit 100 OCT unit 114 retroreflector 114A retroreflector driving unit 118 polarization controller 210 control unit 211 main control unit 212 storage unit 213 scan Control unit 214 Focus control unit 215 Optical path length control unit 220 Image construction unit 230 Data processing unit 231 Area setting unit 232 Order setting unit 233 Condition setting unit 235 Synthesis processing unit

Claims (4)

a region setting unit that sets a plurality of mutually different regions of the fundus of the subject's eye;
By sequentially applying an optical coherence tomography (OCT) scan in a predetermined order and under predetermined conditions to the plurality of regions set by the region setting unit, a plurality of data corresponding to the plurality of regions are obtained. a data collection unit for collecting;
an image constructing unit constructing an image from each of the plurality of data;
a synthesis processing unit that constructs a composite image of the plurality of images constructed from the plurality of data by the image construction unit;
The form of the first area among the plurality of areas is different from the form of the second area,
the dimensions in the depth direction of the plurality of regions are equal to each other;
Prior to the OCT scan for the plurality of regions, the data acquisition unit applies a preliminary OCT scan to the fundus;
the image construction unit constructs a preliminary image from data collected from the preliminary OCT scan;
The region setting unit analyzes the preliminary image to specify a fundus image region that is an image region corresponding to the fundus, and sets the sum region of the plurality of regions so that the sum of the regions substantially includes the fundus image region. An ophthalmologic imaging apparatus, wherein the plurality of regions are set by setting the dimension of each of the plurality of regions in a direction orthogonal to the depth direction. A third region among the plurality of regions is arranged at the center of the fundus, and a fourth region is arranged at the periphery of the fundus,
The ophthalmologic imaging apparatus according to Claim 1, wherein the dimension of the third area in a direction orthogonal to the depth direction is larger than the dimension of the fourth area in the direction. The data acquisition unit includes a measurement arm, which is a path of measurement light projected onto the fundus for the OCT scan, and a reference arm, which is a path of reference light superimposed on the measurement light,
the conditions include an arm length condition indicating at least one of the length of the measurement arm and the length of the reference arm;
an arm length changing unit that changes at least one of the length of the measurement arm and the length of the reference arm;
The ophthalmologic imaging apparatus according to claim 1 or 2, further comprising a first control section that controls the arm length changing section based on the arm length condition. The conditions include a focus condition indicating a focus state of a measurement arm, which is a path of measurement light projected onto the fundus for the OCT scan,
a focus state changing unit that changes the focus state of the measurement arm;
The ophthalmologic photographing apparatus according to any one of claims 1 to 3, further comprising a second control section that controls the focus state changing section based on the focus condition.

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