JP7314345B2 - Ophthalmic device and its control method - Google Patents

Description

The present invention relates to an ophthalmic apparatus and its control method.

Ophthalmologic devices that photograph an eye to be examined include devices using optical coherence tomography (OCT), fundus cameras, scanning laser ophthalmoscopes (SLO), slit lamps, and the like. Among them, OCT, which uses a light beam from a laser light source or the like to form an image representing the surface morphology and internal morphology of a target eye, has attracted attention. Since OCT is not invasive to the human body like X-ray CT, it is expected to be applied particularly in the medical and biological fields. For example, in the field of ophthalmology, devices for forming an image of the anterior segment of an eye to be examined and for measuring the intraocular distance have been put to practical use.

In such an ophthalmologic apparatus, tracking is an important technique for acquiring high-definition images and performing high-precision measurements regardless of the eye movement of the subject's eye. Tracking is to move the apparatus optical system according to the eye movement of the subject's eye. Alignment and focusing are performed prior to tracking. Tracking is a function of maintaining a suitable positional relationship in which alignment and focus are achieved by causing the position of the optical system of the apparatus, etc., to follow the movement of the eyeball.

If the subject's eye moves or blinks during such tracking, it becomes difficult to continue tracking control, making it impossible to perform accurate image acquisition and measurement. For example, Patent Documents 1 to 3 disclose techniques for reducing the influence on accurate image acquisition and measurement even when the subject's eye moves or blinks.

Japanese Patent Application Laid-Open No. 2002-200003 discloses a fundus observation apparatus that obtains the positional displacement of the fundus during scanning and corrects the position of an acquired A-scan image based on the obtained positional displacement.

Further, Patent Literature 2 discloses a fundus camera that detects the blinking of a subject and sets the imaging timing after a predetermined time has elapsed from the detection timing of the blinking.

Further, Patent Literature 3 discloses an ophthalmologic apparatus that predicts a blink occurrence cycle from a result of detection of blink occurrence of a subject, and permits data collection of an eye to be inspected based on the predicted cycle.

JP 2010-264225 A JP 2009-131591 A JP 2016-052386 A

However, the conventional method has the problem that the processing load for reducing the influence on image acquisition and measurement becomes heavy, and the control becomes complicated.

The present invention has been made in view of such circumstances, and its object is to provide a new technique for reducing the influence on accurate image acquisition and measurement with simple control even when the subject's eye moves during tracking control.

One aspect of the embodiment includes an optical scanner, an optical system that deflects light from a light source by the optical scanner and projects it onto an eye to be inspected, and receives light based on the light returned from the eye to be inspected, a movement mechanism that relatively moves the eye to be inspected and the optical system, an image acquisition unit that acquires an image of the eye to be inspected,Beforean image of the subject's eye acquired by the image acquiring unit;, a reference image of the eye to be inspected, which is obtained before the image of the eye to be inspected and serves as a reference for detecting an abnormality;and when an abnormality is detected by the abnormality detection unit,Obtaining the position of the target image based on the alignment target, calculating the amount of movement of the optical system based on the amount of deviation of the target image from the reference position, and calculating the amount of movement based on the calculated amount of movementto control the movement mechanismRuathe alignment control unit and the alignment control unitcontrol of the movement mechanismafter completion, a scan control unit for re-executing the first scan or the second scan by controlling the optical scanner to project light from the light source to the start position of the first scan being executed for the eye to be inspected or the second scan executed before the first scan at the acquisition timing of the image of the eye to be inspected; and a tracking control unit that controls the moving mechanism, after re-executing the first scan or the second scan, the image acquisition unit re-acquires the image of the eye to be inspected, and the abnormality detection unitthe reference image andthe reacquired imageandIt is an ophthalmologic apparatus that detects the abnormality using

Another aspect of the embodiment is a control method for an ophthalmologic apparatus including an optical system that includes an optical scanner, deflects light from a light source by the optical scanner, projects the light onto an eye to be inspected, and receives light based on light returned from the eye to be inspected, and a moving mechanism that relatively moves the eye to be inspected and the optical system.眼科装置の制御方法は、前記被検眼の画像を取得する画像取得ステップと、前記被検眼の画像と、前記被検眼の画像よりも前に取得され異常を検知する際の基準となる前記被検眼の基準画像とに基づいて異常を検知する異常検知ステップと、前記異常が検知されたとき、アライメント視標に基づく視標像の位置を求め、基準位置に対する前記視標像のずれ量に基づいて前記光学系の移動量を算出し、算出された前記移動量に基づいて前記移動機構を制御するアライメント制御ステップと、前記アライメント制御ステップにおける前記移動機構の制御が完了した後に、前記被検眼の画像の取得タイミングで前記被検眼に対して実行中の第１スキャン又は前記第１スキャンより前に実行された第２スキャンの開始位置に前記光源からの光を投射するように前記光スキャナを制御して前記第１スキャン又は前記第２スキャンを再実行させるスキャン制御ステップと、前記異常が検知されなかったとき、前記基準画像と前記被検眼の画像とに基づいて前記被検眼の動きに前記光学系を追従させるように前記移動機構を制御するトラッキング制御部ステップと、を含み、前記第１スキャン又は前記第２スキャンを再実行した後、前記画像取得ステップが前記被検眼の画像が再取得し、前記異常検知ステップが前記基準画像と前記再取得された画像とを用いて前記異常の検知を行う。

According to the present invention, even when the subject's eye moves during tracking control, it is possible to reduce the influence on accurate image acquisition and measurement with simple control.

It is a schematic diagram showing an example of the configuration of the optical system of the ophthalmologic apparatus according to the embodiment. It is a schematic diagram showing an example of the configuration of the optical system of the ophthalmologic apparatus according to the embodiment. 1 is a schematic diagram showing an example of a configuration of a processing system of an ophthalmologic apparatus according to an embodiment; FIG. 1 is a schematic diagram showing an example of a configuration of a processing system of an ophthalmologic apparatus according to an embodiment; FIG. FIG. 4 is a flow diagram of an operation example of the ophthalmologic apparatus according to the embodiment; FIG. 4 is a flow diagram of an operation example of the ophthalmologic apparatus according to the embodiment;

An ophthalmologic apparatus according to the present invention and an example of an embodiment of a control method thereof will be described in detail with reference to the drawings. It should be noted that the descriptions of the documents cited in this specification and any known techniques can be incorporated into the following embodiments.

An ophthalmologic apparatus according to an embodiment includes an optical scanner, deflects light from a light source by the optical scanner, projects the light onto an eye to be inspected, and receives light based on return light from the eye to be inspected (including part of the returned light), and is capable of acquiring information about the eye to be inspected. Such optical systems include an OCT optical system, an SLO optical system, and the like. The OCT optical system divides the light from the OCT light source into measurement light and reference light, projects the measurement light onto the subject's eye via an optical scanner, and receives interference light between the return light of the measurement light from the subject's eye and the reference light that has passed through the reference optical path. The SLO optical system projects SLO light from an SLO light source onto an eye to be inspected via an optical scanner, and receives return light of the SLO light from the eye to be inspected.

A case where the ophthalmologic apparatus according to the embodiment performs OCT on the eye to be examined to form an image of the eye will be described below, but the embodiment is not limited to this. For example, the ophthalmologic apparatus according to the embodiment may be capable of measuring the intraocular distance of the living eye such as the axial length by performing OCT on the subject's eye, and may be capable of forming an SLO image.

An ophthalmologic apparatus according to an embodiment is an ophthalmologic apparatus that combines Fourier domain OCT and a fundus camera. Although this ophthalmic apparatus has the capability to perform swept-source OCT, embodiments are not limited thereto. For example, the type of OCT is not limited to swept source OCT, and may be spectral domain OCT or the like. Swept source OCT is a method of dividing light from a wavelength swept (wavelength scanning) light source into measurement light and reference light, causing the return light of the measurement light that has passed through the object to be measured to interfere with the reference light to generate interference light, detect this interference light with a balanced photodiode or the like, and perform Fourier transformation or the like on detection data collected according to wavelength sweeping and measurement light scanning to form an image. Spectral domain OCT is a technique in which light from a low-coherence light source is split into measurement light and reference light, the return light of the measurement light that has passed through the object to be measured interferes with the reference light to generate interference light, the spectral distribution of this interference light is detected by a spectrometer, and the detected spectral distribution is subjected to Fourier transform or the like to form an image.

Instead of the fundus camera, the ophthalmologic apparatus according to the embodiment may be provided with a scanning laser ophthalmoscope (SLO), a slit lamp microscope, an anterior segment imaging camera, a surgical microscope, a photocoagulator, or the like. In this specification, measurement by OCT is collectively referred to as "OCT measurement", images acquired by OCT are collectively referred to as OCT images, the optical path of measurement light is sometimes referred to as "measurement optical path", and the optical path of reference light is sometimes referred to as "reference optical path".

[composition]
As shown in FIG. 1 , an ophthalmologic apparatus 1 according to the embodiment includes a fundus camera unit 2 , an OCT unit 100 and an arithmetic control unit 200 . The retinal camera unit 2 has an optical system substantially similar to that of a conventional retinal camera. The OCT unit 100 is provided with an optical system for performing OCT. The arithmetic control unit 200 includes a processor that executes various kinds of arithmetic processing, control processing, and the like.

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)), etc. 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]
The fundus camera unit 2 is provided with an optical system for acquiring a two-dimensional image (fundus image) representing the surface morphology of the fundus Ef of the eye E to be examined. The fundus image includes an observed image, a photographed image, and the like. The observed image is, for example, a monochrome moving image formed at a predetermined frame rate using near-infrared light. The captured image may be, for example, a color image obtained by flashing visible light, or a monochrome still image using near-infrared light or visible light as illumination light. The fundus camera unit 2 may be configured to be able to acquire images other than these, such as fluorescein fluorescence images, indocyanine green fluorescence images, autofluorescence images, and the like.

The retinal camera unit 2 is provided with a chin rest and a forehead rest for supporting the subject's face. Furthermore, the retinal camera unit 2 is provided with an illumination optical system 10 and a photographing optical system 30 . The illumination optical system 10 illuminates the fundus oculi Ef with illumination light. The imaging optical system 30 guides the fundus reflected light of this illumination light to imaging devices (CCD image sensors (sometimes simply called CCDs) 35 and 38). Further, the imaging optical system 30 guides the measurement light from the OCT unit 100 to the eye E to be inspected, and guides the measurement light passing through the eye E to be inspected to the OCT unit 100 .

The observation light source 11 of the illumination optical system 10 is composed of, for example, a halogen lamp or an LED (Light Emitting Diode). Light (observation illumination light) output from an observation light source 11 is reflected by a reflecting mirror 12 having a curved reflecting surface, passes through a condenser lens 13, passes through a 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 lenses 17 and 18 , the diaphragm 19 and the relay lens 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 fundus oculi Ef.

The fundus reflected light of the observation illumination light is refracted by the objective lens 22, passes through the dichroic mirror 46, passes through a hole formed in the central region of the perforated mirror 21, passes through the dichroic mirror 55, passes through the photographing focusing lens 31, and is reflected by the mirror 32. Further, this fundus reflected light passes through the half mirror 33A, is reflected by the dichroic mirror 33, and is imaged on the light receiving surface of the CCD image sensor 35 by the condenser lens . The CCD image sensor 35 detects the fundus reflected light at a predetermined frame rate, for example. The display device 3 displays an image (observation image) based on the fundus reflected light detected by the CCD image sensor 35 . When the imaging optical system 30 is focused on the anterior segment, the CCD image sensor 35 detects the reflected light of the observation illumination light from the anterior segment, and an observation image of the anterior segment based on the reflected light is displayed on the display device 3.

The imaging light source 15 is composed of, for example, a xenon lamp or an LED. 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 fundus reflected light of the photographing illumination light is guided to the dichroic mirror 33 through the same path as that of the observation illumination light, passes through the dichroic mirror 33, is reflected by the mirror 36, and is imaged on the light receiving surface of the CCD image sensor 38 by the condenser lens 37. An image (captured image) based on the fundus reflected light detected by the CCD image sensor 38 is displayed on the display device 3 . The display device 3 that displays the observed image and the display device 3 that displays the captured image may be the same or different. In addition, when the subject's eye E is illuminated with infrared light and similar photographing is performed, an infrared photographed image is displayed. Moreover, it is also possible to use an LED as a light source for photographing. When the imaging optical system 30 is focused on the anterior segment, the CCD image sensor 38 detects the reflected light of the observation illumination light from the anterior segment, and the image of the anterior segment based on the reflected light (captured image) is displayed on the display device 3.

An LCD (Liquid Crystal Display) 39 displays a fixation target and visual acuity measurement target. The fixation target is a target for fixating the subject's eye E, and is used during fundus imaging, OCT measurement, and the like.

A part of the light output from the LCD 39 is reflected by the half mirror 33A, 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 light passing through the aperture of the perforated mirror 21 is transmitted through the dichroic mirror 46, refracted by the objective lens 22, and irradiated to the fundus oculi Ef. By changing the display position of the fixation target on the screen of the LCD 39, the fixation position of the subject's eye E can be changed.

Further, the retinal camera unit 2 is provided with an alignment optical system 50 and a focus optical system 60, like a conventional retinal camera. The alignment optical system 50 generates a target (alignment target) for aligning the device optical system with the eye E to be inspected. The focus optical system 60 generates a target (split target) for focusing on the eye E to be examined.

Light (alignment light) output from the LED 51 of the alignment optical system 50 passes through the apertures 52 and 53 and the relay lens 54 , is reflected by the dichroic mirror 55 , and passes through the aperture of the aperture mirror 21 . The light passing through the aperture of the perforated mirror 21 passes through the dichroic mirror 46 and is irradiated onto the cornea of the subject's eye E by the objective lens 22 .

The cornea-reflected light of the alignment light passes through the objective lens 22 , the dichroic mirror 46 and the hole, and a part of it passes through the dichroic mirror 55 and passes through the imaging focusing lens 31 . The corneal reflected light that has passed through the photographing focusing lens 31 is reflected by the mirror 32, transmitted through the half mirror 33A, reflected by the dichroic mirror 33, and projected onto the light receiving surface of the CCD image sensor 35 by the condenser lens 34. A received image (alignment target) by the CCD image sensor 35 is displayed on the display device 3 together with the observed image. The user carries out alignment by performing operations similar to those of a conventional fundus camera. Alternatively, the arithmetic and control unit 200 may analyze the position of the alignment index and move the optical system to perform alignment (auto-alignment function).

The focus optical system 60 is movable along the optical path of the illumination optical system 10 . The imaging focusing lens 31 can move along the optical path of the imaging optical system 30 in conjunction with the movement of the focusing optical system 60 . The reflecting bar 67 of the focus optical system 60 is removable with respect to the illumination optical path.

When performing focus adjustment, the reflecting surface of the reflecting bar 67 is obliquely provided on the illumination optical path. Light (focus light) output from the LED 61 of the focus optical system 60 passes through the relay lens 62 , is split into two light fluxes by the split optotype plate 63 , and passes through the double aperture diaphragm 64 . The light passing through the two-aperture diaphragm 64 is reflected by the mirror 65, and once imaged on the reflecting surface of the reflecting bar 67 by the condenser lens 66, and then reflected. The light reflected by the reflecting surface of the reflecting rod 67 passes through the relay lens 20, is reflected by the perforated mirror 21, passes through the dichroic mirror 46, is refracted by the objective lens 22, and is irradiated to the subject's eye E as a pair of split target lights.

A pair of split target lights that have passed through the pupil of the eye E to be examined reach the fundus Ef of the eye E to be examined. The fundus reflected light of the pair of split target lights passes through the pupil and is detected by the CCD image sensor 35 through the same path as the fundus reflected light flux of the illumination light. A received image (a pair of split target images) by the CCD image sensor 35 is displayed on the display device 3 together with the observed image. The arithmetic control unit 200 analyzes the positions of the pair of split target images and moves the focus optical system 60 to perform focusing (autofocus function), as in the conventional art. By moving the photographing focusing lens 31 in conjunction with the movement of the focusing optical system 60 , the fundus image is formed on the imaging surface of the CCD image sensor 35 . Alternatively, focusing may be performed manually (by operating the operation unit 240B, which will be described later) while visually recognizing the pair of split optotype images.

The reflecting rod 67 is inserted at a position on the illumination optical path that is optically substantially conjugate with the fundus Ef of the eye E to be examined. The position of the reflecting surface of the reflecting rod 67 inserted in the optical path of the illumination optical system 10 is a position substantially conjugate optically with the split optotype plate 63 . The focus target light is split into two by the action of the double-aperture diaphragm 64 or the like, as described above. When the fundus oculi Ef and the reflecting surface of the reflecting rod 67 are not conjugate, the pair of split target images acquired by the CCD image sensor 35 are displayed on the display device 3 after being separated into two in the horizontal direction, for example. When the fundus oculi Ef and the reflecting surface of the reflecting rod 67 are substantially conjugate, the pair of split target images acquired by the CCD image sensor 35 are displayed on the display device 3, for example, aligned in the vertical direction. When the focusing optical system 60 is moved along the illumination optical path so that the fundus oculi Ef and the split optotype plate 63 are always optically conjugate, the photographing focusing lens 31 is moved along the photographing optical axis. When the fundus oculi Ef and the split optotype plate 63 are not conjugated, the pair of split optotype images are separated into two. Therefore, the position of the photographing focusing lens 31 is obtained by moving the focusing optical system 60 so that the pair of split optotype images coincide with each other in the vertical direction. In this embodiment, a case where a pair of split optotype images is acquired has been described, but three or more split optotype images may be obtained.

The dichroic mirror 46 branches the optical path for OCT from the optical path for observation/imaging. The dichroic mirror 46 reflects light in the wavelength band used for OCT and transmits light for observation and photography. The optical path for OCT is provided with a collimator lens unit 40, an optical path length changing section 41, an optical scanner 42, an OCT focusing lens 43, a mirror 44, and a relay lens 45 in this order from the OCT unit 100 side.

Collimator lens unit 40 includes a collimator lens. The collimator lens unit 40 is optically connected to the OCT unit 100 via optical fibers. A collimator lens of the collimator lens unit 40 is arranged at a position facing the output end of the optical fiber. The collimator lens unit 40 collimates the measurement light LS (described later) emitted from the output end of the optical fiber, and collects the return light of the measurement light from the subject's eye E to the output end.

The optical path length changing unit 41 is movable in the direction of the arrow shown in FIG. 1, and changes the optical path length of the optical path for OCT. This change in the optical path length is used for correction of the optical path length according to the axial length of the eye E to be examined, adjustment of the interference state, and the like. The optical path length changing unit 41 includes, for example, a corner cube and a mechanism for moving it.

The optical scanner 42 is arranged at a position substantially optically conjugate with the pupil of the eye E to be examined, for example. The optical scanner 42 changes the traveling direction of light (measurement light LS) passing through the optical path for OCT. Thereby, the subject's eye E can be scanned with the measurement light LS. The optical scanner 42 includes, for example, a galvanomirror for scanning the measurement light LS in the x direction, a galvanomirror for scanning in the y direction, and a mechanism for independently driving these. Thereby, the measurement light LS can be scanned in any direction on the xy plane.

The OCT focusing lens 43 is movable along the optical path of the measurement light LS (the optical axis of the interference optical system).

The ophthalmologic apparatus 1 is provided with a front lens 23 that can be arranged between the subject's eye E and the objective lens 22 . The front lens 23 can be manually arranged between the eye E to be examined and the objective lens 22 . The front lens 23 may be automatically arranged between the subject's eye E and the objective lens 22 under the control of the control unit 210, which will be described later. When the head lens 23 is retracted from between the eye E to be examined and the objective lens 22, the focal position of the measurement light is arranged at or near the fundus Ef of the eye E to be examined, and OCT measurement can be performed on the fundus Ef. When the front lens 23 is arranged between the eye E to be examined and the objective lens 22, the focal position of the measurement light is moved from the fundus oculi Ef and arranged in the anterior segment or its vicinity, and OCT measurement can be performed on the anterior segment.

[OCT unit]
An example of the configuration of the OCT unit 100 is shown in FIG. The OCT unit 100 is provided with an optical system for acquiring an OCT image of the eye E to be examined. This optical system is an interference optical system that divides light from a wavelength sweeping (wavelength scanning) light source into measurement light and reference light, generates interference light by causing the return light of the measurement light from the eye E to interfere with the reference light that has passed through the reference optical path, and detects this interference light. A detection result (detection signal) of the interference light by the interference optical system is an interference signal indicating the spectrum of the interference light, and is sent to the arithmetic control unit 200 .

The light source unit 101 includes a wavelength sweeping (wavelength scanning) light source capable of sweeping (scanning) the wavelength of emitted light, like a general swept source type ophthalmologic apparatus. A wavelength-swept light source includes a laser light source including a resonator. The light source unit 101 temporally changes the output wavelength in the near-infrared wavelength band invisible to the human eye.

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. The polarization controller 103 adjusts the polarization state of the light L0 guided through the optical fiber 102 by, for example, externally applying stress to the looped optical fiber 102 .

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

The reference light LR is guided to a collimator 111 by an optical fiber 110 and becomes a parallel light beam. The reference light LR, which has become a parallel light flux, is guided to the optical path length changing section 114 . The optical path length changing unit 114 is movable in the direction of the arrow shown in FIG. 2, and changes the optical path length of the reference light LR. This movement changes the length of the optical path of the reference light LR. This change in the optical path length is used for correction of the optical path length according to the axial length of the eye E to be examined, adjustment of the interference state, and the like. The optical path length changing unit 114 includes, for example, a corner cube and a moving mechanism for moving it. In this case, the corner cube of the optical path length changing unit 114 reverses the traveling direction of the reference light LR that has been collimated by the collimator 111 . The optical path of the reference light LR entering the corner cube and the optical path of the reference light LR emerging from the corner cube are parallel.

1 and 2, both an optical path length changing unit 41 for changing the length of the optical path of the measurement light LS (measurement optical path, measurement arm) and an optical path length changing unit 114 for changing the length of the optical path of the reference light LR (reference optical path, reference arm) are provided. However, only one of the optical path length changers 41 and 114 may be provided. It is also possible to change the difference between the reference optical path length and the measurement optical path length by using optical members other than these.

The reference light LR that has passed through the optical path length changing unit 114 is converted by the collimator 116 from a parallel beam into a converged beam and enters the optical fiber 117 .

An optical path length correction member may be arranged in at least one of the reference optical path between the collimator 111 and the optical path length changing section 114 and the reference optical path between the collimator 116 and the optical path length changing section 114 . The optical path length correction member acts as delay means for matching the optical path length (optical distance) of the reference light LR and the optical path length of the measurement light LS.

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

On the other hand, the measurement light LS generated by the fiber coupler 105 is guided by the optical fiber 127 and made into a parallel light beam by the collimator lens unit 40 . The collimated measurement light LS is guided to the dichroic mirror 46 via the optical path length changing section 41 , the optical scanner 42 , the OCT focusing lens 43 , the mirror 44 and the relay lens 45 . The measurement light LS guided to the dichroic mirror 46 is reflected by the dichroic mirror 46, refracted by the objective lens 22, and irradiated to the eye E to be examined. The measurement light LS is scattered (including reflected) at various depth positions of the eye E to be examined. The return light of the measurement light LS including such backscattered light 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 combines (interferences) the measurement light LS that has entered via the optical fiber 128 and the reference light LR that has entered via the optical fiber 121 to generate interference light. The fiber coupler 122 splits the interference light between the measurement light LS and the reference light LR at a predetermined splitting ratio (for example, 1:1) to generate a pair of interference lights LC. A pair of interference lights LC emitted from the fiber coupler 122 are guided to a detector 125 by optical fibers 123 and 124, respectively.

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

[Calculation control unit]
A configuration of the arithmetic control unit 200 will be described. The arithmetic control unit 200 analyzes the interference signal input from the detector 125 and forms an OCT image of the eye E to be examined. Arithmetic processing for forming an OCT image is similar to that of a conventional swept source type ophthalmic apparatus.

Further, the arithmetic control unit 200 controls each part of the fundus camera unit 2 , the display device 3 and the OCT unit 100 . For example, the arithmetic control unit 200 causes the display device 3 to display an OCT image of the eye E to be examined.

The arithmetic control unit 200 includes, for example, a microprocessor, a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk drive, a communication interface, etc., like a conventional computer. A computer program for controlling the ophthalmologic apparatus 1 is stored in a storage device such as a hard disk drive. The arithmetic and control unit 200 may include various circuit boards, for example, a circuit board for forming OCT images. The arithmetic control unit 200 may also include an operation device (input device) such as a keyboard and mouse, and a display device such as an LCD.

[Processing system]
The configuration of the processing system of the ophthalmologic apparatus 1 will be described with reference to FIGS. 3 and 4. FIG. Note that FIG. 3 omits some components of the ophthalmologic apparatus 1 and selectively shows components particularly necessary for explaining this embodiment.

(control part)
Arithmetic control unit 200 includes a control section 210 , an image forming section 220 and a data processing section 230 . The control unit 210 includes, for example, a microprocessor, RAM, ROM, hard disk drive, communication interface, and the like. The control unit 210 is provided with a main control unit 211 and a storage unit 212 .

The functions of the main control unit 211 are implemented by, for example, a microprocessor (that is, “processor”). A computer program for controlling the ophthalmologic apparatus is stored in advance in the storage unit 212 . The computer programs include various light source control programs, optical scanner control programs, various detector control programs, image forming programs, data processing programs, user interface programs, and the like. The main control unit 211 operates according to such a computer program, so that the control unit 210 executes control processing.

(main controller)
The main control unit 211 performs various controls described above. In particular, as shown in FIG. 3, the main controller 211 controls the focus drivers 31A and 43A, the CCD image sensors 35 and 38, the LCD 39, the optical path length changer 41, and the optical scanner 42 of the retinal camera unit 2. Further, the main control section 211 controls the optical system driving section 1A. Furthermore, the main control section 211 controls the light source unit 101 of the OCT unit 100, the optical path length changing section 114, the detector 125, the DAQ 130, and the like.

The focus driving section 31A receives control from the main control section 211 and moves the photographing focusing lens 31 along the optical axis of the photographing optical system 30 . The focus driving section 31A is provided with a holding member that holds the photographing focusing lens 31, an actuator that generates driving force for moving the holding member, and a transmission mechanism that transmits this driving force. The actuator is composed of, for example, a pulse motor. The transmission mechanism is configured by, for example, a combination of gears, a rack and pinion, or the like. As a result, the focus driving section 31A controlled by the main control section 211 moves the photographing focusing lens 31, thereby changing the focus position of the photographing optical system 30. FIG. Note that the focus driving section 31A may move the photographing focusing lens 31 along the optical axis of the photographing optical system 30 manually or by the user's operation on the operation section 240B.

The focus driver 43A receives control from the main controller 211 and moves the OCT focus lens 43 along the optical axis of the interference optical system (the optical path of the measurement light) in the OCT unit 100 . The focus driving section 43A is provided with a holding member that holds the OCT focusing lens 43, an actuator that generates driving force for moving the holding member, and a transmission mechanism that transmits this driving force. The actuator is composed of, for example, a pulse motor. The transmission mechanism is configured by, for example, a combination of gears, a rack and pinion, or the like. As a result, the focus drive unit 43A controlled by the main control unit 211 moves the OCT focus lens 43, thereby changing the focus position of the measurement light. Note that the focus drive unit 43A may move the OCT focus lens 43 along the optical axis of the interference optical system manually or by the user's operation on the operation unit 240B.

The main controller 211 can control the exposure time (charge accumulation time), sensitivity, frame rate, etc. of the CCD image sensor 35 . The main controller 211 can control the exposure time, sensitivity, frame rate, etc. of the CCD image sensor 38 .

The main control unit 211 can control the display of the fixation target and visual acuity measurement target on the LCD 39 . As a result, it becomes possible to switch the visual target presented to the eye E to be examined and change the type of the visual target. Further, by changing the display position of the optotype on the LCD 39, it is possible to change the optotype presenting position for the eye E to be examined.

The main control unit 211 can relatively change the difference between the optical path length of the reference light LR and the optical path length of the measurement light LS by controlling the optical path length changing unit 41 . The main control unit 211 controls the optical path length changing unit 41 so that the target portion of the eye E to be examined is rendered in a predetermined range within the frame of the OCT image. Specifically, the main control unit 211 can control the optical path length changing unit 41 so that the target portion of the eye E to be examined is rendered at a predetermined z position (position in the depth direction) within the frame of the OCT image.

The main controller 211 can change the projection position of the measurement light LS on the fundus Ef of the eye E to be examined or the anterior segment of the eye by controlling the optical scanner 42 .

The optical system driving unit 1A three-dimensionally moves the optical system (the optical system shown in FIGS. 1 and 2) provided in the ophthalmologic apparatus 1. FIG. The optical system drive unit 1A receives control from the main control unit 211 and moves the optical system. This control is used in alignment and tracking. Tracking is to move the apparatus optical system according to the movement of the eye E to be examined. Alignment and focusing are performed in advance when tracking is performed. Tracking is a function that maintains a suitable positional relationship in alignment and focus by moving the device optical system in real time according to the position and orientation of the eye E to be inspected based on an image obtained by capturing a moving image of the eye E to be inspected.

By controlling the light source unit 101, the main control unit 211 can control switching between lighting and extinguishing of the light L0, change of the light amount of the light L0, and the like.

The main control unit 211 can relatively change the difference between the optical path length of the reference light LR and the optical path length of the measurement light LS by controlling the optical path length changing unit 114 . The main control unit 211 controls the optical path length changing unit 114 so that the target portion of the eye E to be examined is rendered in a predetermined range within the frame of the OCT image. Specifically, the main control unit 211 can control the optical path length changing unit 114 so that the target region of the eye E to be examined is rendered at a predetermined z position within the frame of the OCT image. The main controller 211 can relatively change the difference between the optical path length of the reference light LR and the optical path length of the measurement light LS by controlling at least one of the optical path length changers 41 and 114 . In the following description, the main control unit 211 adjusts the optical path length difference between the measurement light LS and the reference light LR by controlling only the optical path length changing unit 114. However, the optical path length difference between the reference light LR and the measurement light LS may be adjusted by controlling only the optical path length changing unit 41.

The main controller 211 can control the exposure time (charge accumulation time), sensitivity, frame rate, etc. of the detector 125 . Also, the main control unit 211 can control the DAQ 130 .

As shown in FIG. 4, the main controller 211 includes an alignment controller 211A, a tracking controller 211B, and a scan controller 211C.

The alignment control unit 211A controls execution of alignment for aligning the apparatus optical system (the optical system shown in FIGS. 1 and 2) with the eye E to be examined. For example, an alignment target by the alignment optical system 50 and a split target by the focus optical system 60 are projected onto the eye E to be examined. In the anterior segment image of the subject's eye E obtained by the imaging optical system 30, a target image based on the alignment target is depicted. For example, the data processing unit 230, which will be described later, obtains the amount of movement of the device optical system based on the positional deviation of the visual target image with respect to the reference position in the anterior segment image. The alignment control section 211A can control the optical system driving section 1A based on the calculated movement amount.

Further, the alignment control section 211A can control the optical system driving section 1A based on the anterior segment image of the subject's eye E obtained by the imaging optical system 30 . The alignment control unit 211A, for example, identifies a characteristic position in the anterior segment image of the subject's eye E obtained by the imaging optical system 30, and determines the amount of movement of the device optical system so as to cancel the amount of deviation between the identified characteristic position and a predetermined target position. The alignment controller 211A aligns the apparatus optical system with the subject's eye E by controlling the optical system driver 1A based on the obtained movement amount (xy direction). The target position may be a position determined in advance, or a position in the anterior segment image designated using the operation unit 240B.

Similarly, the alignment control section 211A can perform alignment by controlling the optical system driving section 1A based on the fundus image of the subject's eye E obtained by the photographing optical system 30 .

The alignment control unit 211A can, for example, identify the focus state (defocus) of the anterior segment image (or fundus image) of the subject's eye E obtained by the imaging optical system 30, and obtain the amount of movement of the device optical system in the z direction so that the identified focus state becomes a desired focus state. The alignment control unit 211A controls the optical system driving unit 1A based on the obtained movement amount, thereby aligning the apparatus optical system with the subject's eye E (z direction). Alternatively, two or more cameras may be used to photograph the anterior segment of the eye from different directions, three-dimensionally identify the in-focus state from the two or more images provided with parallax, and determine the amount of movement of the device optical system in the z-direction so that the identified in-focus state becomes the desired in-focus state.

The tracking control unit 211B controls tracking of the anterior segment image (or fundus image) of the subject's eye E obtained by the imaging optical system 30 . For example, the tracking control unit 211B identifies a feature position in the anterior segment image (or fundus image) at a predetermined timing, and when the identified feature position changes, obtains a movement amount so as to cancel the shift amount of the position. The tracking control unit 211B controls tracking of the anterior eye image (or fundus image) by controlling the optical system driving unit 1A based on the obtained movement amount.

In this embodiment, the tracking control unit 211B performs tracking control by a method corresponding to the observation site (imaging site, measurement site, data collection site). When the front lens 23 is retracted from between the subject's eye E and the objective lens 22, the tracking control section 211B performs tracking control in the fundus mode. When the front lens 23 is arranged between the subject's eye E and the objective lens 22, the tracking control section 211B performs tracking control in the anterior segment mode.

(fundus mode)
In the fundus mode, the tracking control unit 211B performs tracking control based on the fundus image of the subject's eye E obtained by the imaging optical system 30 . Fundus images are obtained as a base image and a target image at different timings. A base image corresponds to a reference image. That is, the tracking control unit 211B can obtain the positional deviation amount (including the positional deviation direction) of the target image, which is the fundus image obtained after obtaining the base image, with reference to the base image, which is the fundus image of the eye E to be examined, obtained in advance, and can perform tracking control based on the obtained positional deviation amount. The tracking control section 211B can control the optical system driving section 1A based on the obtained positional deviation amount.

Note that the displacement amount of the target image with respect to the base image may be obtained by performing phase-only correlation processing on the base image and the target image. In this case, the amount of misregistration includes the amount of sub-pixel level rotational movement (rotational direction about the z-axis) of less than one pixel between the base image and the target image and its direction of rotational movement, the amount of translation in the xy plane at the sub-pixel level between the base image and the target image and its direction of translation, and the like. Specifically, the data processing unit 230 calculates the amount of rotational movement and the direction of rotational movement between the base image and the target image at the sub-pixel level by phase-only correlation processing, and aligns the rotation direction between the base image and the target image based on the calculated amount of rotational movement and the rotational movement direction. The data processing unit 230 then calculates the amount and direction of translation between the aligned base and target images at the sub-pixel level. Such phase-only correlation processing is the same as the processing disclosed in Japanese Patent Application Laid-Open No. 2015-043898.

(Anterior segment mode)
In the anterior segment mode, the tracking control unit 211B performs tracking control based on the anterior segment image of the subject's eye E obtained by the imaging optical system 30 . The anterior segment images are obtained as the base image and the target image at different timings. A base image corresponds to a reference image. That is, the tracking control unit 211B can obtain the positional deviation amount (including the direction of positional deviation) of the target image, which is the anterior segment image of the subject's eye E, obtained after obtaining the base image based on the base image, which is the anterior segment image of the subject's eye E, obtained in advance, and can perform tracking control based on the obtained positional deviation amount. Note that the displacement amount of the target image with respect to the base image may be obtained by performing phase-only correlation processing on the base image and the target image. The tracking control section 211B can control the optical system driving section 1A based on the obtained positional deviation amount.

The scan controller 211C controls the optical scanner 42 to change the projection position of the measurement light LS in the horizontal direction or the vertical direction (the direction substantially perpendicular to the depth direction) of the observation site (anterior segment or fundus) of the eye E to be examined. The scan controller 211C can control the start position and end position of each scan and the deflection angle of the measurement light LS for the optical scanner 42 based on the preset scan area and scan pattern.

In the embodiment, scanning modes by the measurement light LS include, for example, horizontal scanning, vertical scanning, cross scanning, radial scanning, circular scanning, concentric scanning, spiral scanning, and the like. These scanning modes are appropriately and selectively used in consideration of the observation site in the anterior segment or fundus, the analysis target (retinal thickness, etc.), the time required for scanning, the precision of scanning, and the like.

Horizontal scanning changes the projection position of the measurement light LS in the horizontal direction (x direction). Horizontal scanning also includes a mode in which the projection position of the measurement light LS is changed along a plurality of horizontally extending scanning lines arranged in the vertical direction (y direction). In this aspect, the spacing between scanning lines can be set arbitrarily. Also, by sufficiently narrowing the interval between adjacent scanning lines, a three-dimensional image can be formed (three-dimensional scanning). The same is true for vertical scanning.

The cross scan changes the projection position of the measurement light LS along a cross-shaped trajectory made up of two linear trajectories (linear trajectories) orthogonal to each other. A radial scan changes the projection position of the measurement light LS along a radial trajectory composed of a plurality of linear trajectories arranged at predetermined angles. Cross scanning is an example of radial scanning.

A circular scan changes the projection position of the measurement light LS along a circular trajectory. The concentric circle scan changes the projection position of the measurement light LS along a plurality of circular trajectories concentrically arranged around a predetermined central position. A circular scan can be considered a special case of a concentric circle scan. The spiral scan changes the projection position of the measurement light LS along a spiral (spiral) trajectory while gradually decreasing (or increasing) the radius of rotation.

In this embodiment, as will be described later, based on the anterior segment image or fundus image, a state in which it is difficult to continue tracking control, such as movement of the subject's eye or occurrence of blinking, is detected as an abnormal state. At least one of the tracking control unit 211B and the scan control unit 211C can perform the following control based on the abnormal state detection result.

The tracking control unit 211B controls the optical system driving unit 1A so that the apparatus optical system follows the movement of the subject's eye based on the base image and the target image when the above abnormality is not detected. On the other hand, when the above abnormality is detected, the scan control unit 211C controls the optical scanner 42 to project the measurement light LS to the start position of the first scan being executed at the acquisition timing of the target image or the second scan executed before the first scan, and re-executes the first scan or the second scan. Here, the first scan may be a horizontal scan, a vertical scan, a cross scan, a radial scan, a circular scan, a concentric circle scan, or a helical (spiral) scan. The second scan may be a scan performed immediately before the first scan or a scan performed two or more times before the first scan. The second scan may be a scan performed a predetermined time before the first scan, taking into consideration the processing load and the complexity of control. The second scan, like the first scan, can also be a horizontal scan, vertical scan, cross scan, radial scan, circular scan, concentric circle scan, or spiral scan. Note that the scan control unit 211C may re-execute the first scan or the second scan after the alignment control unit 211A completes the alignment of the device optical system with respect to the eye E to be examined. The scan control unit 211C can perform rescanning in units of scans in the direction intersecting the measurement light LS.

(storage unit)
The storage unit 212 stores various data. The data stored in the storage unit 212 includes, for example, image data of an OCT image, image data of a fundus image or an anterior segment image, eye information to be examined, and the like. The eye information to be examined includes information about the subject such as patient ID and name, and information about the eye to be examined such as left/right eye identification information. The main control unit 211 can store abnormality occurrence information, which will be described later, in the storage unit 212 in association with eye information to be examined. The storage unit 212 also stores data such as various programs and control information for operating the ophthalmologic apparatus 1 .

(Image forming section)
The image forming unit 220 forms image data of tomographic images of the fundus oculi Ef and the anterior segment based on the interference signal from the detector 125 (DAQ 130). This processing includes processing such as noise removal (noise reduction), filtering, and FFT (Fast Fourier Transform). The image data acquired in this way is a data set including a group of image data formed by imaging reflection intensity profiles in a plurality of A-lines (paths of each measuring light LS in the eye E to be examined).

To improve image quality, multiple data sets collected by scanning the same pattern multiple times can be superimposed (averaged).

Further, the image forming unit 220 can form an anterior segment image based on detection results of light reflected from the anterior segment of the subject's eye E by the CCD image sensor 35 and the CCD image sensor 38 .

The image forming section 220 includes, for example, the aforementioned circuit board. In this specification, "image data" and "images" based thereon may be regarded as the same. Also, the site of the subject's eye E and its image may be viewed as the same.

(Data processing part)
The data processing section 230 performs various data processing (image processing) and analysis processing on the image formed by the image forming section 220 . For example, the data processing unit 230 executes correction processing such as luminance correction and dispersion correction of an image.

The data processing unit 230 can form volume data (voxel data) of the subject's eye E by executing known image processing such as interpolation processing for interpolating pixels between tomographic images. When displaying an image based on volume data, the data processing unit 230 performs rendering processing on this volume data to form a pseudo three-dimensional image when viewed from a specific viewing direction.

The data processing unit 230 can align the fundus image (or the anterior segment image) and the OCT image. When the fundus image (or anterior segment image) and the OCT image are acquired in parallel, since both optical systems are coaxial, the fundus image (or anterior segment image) and the OCT image acquired (almost) simultaneously can be aligned with the optical axis of the imaging optical system 30 as a reference. In addition, regardless of the acquisition timing of the fundus image (or anterior eye image) and the OCT image, it is possible to align the OCT image and the fundus image (or anterior eye image) by aligning the fundus image (or anterior eye image) with the front image obtained by projecting at least part of the corresponding image region of the fundus Ef (or anterior eye image) of the OCT image onto the xy plane. This alignment method can be applied even when the optical system for acquiring the fundus image (or for acquiring the anterior segment image) and the optical system for OCT are not coaxial. Also, even if both optical systems are not coaxial, if the relative positional relationship between both optical systems is known, it is possible to refer to this relative positional relationship and perform the same alignment as in the case of coaxial.

Data processing unit 230 includes analysis unit 231 . The analysis unit 231 performs analysis processing on the anterior segment image or fundus image obtained by the imaging optical system 30 . The analysis processing includes processing for specifying a feature region and a feature position (feature point) in an image, processing for detecting movement of the subject's eye E, occurrence of blinking or flare, and the like.

(Anterior segment mode)
In the anterior segment mode, the analysis unit 231 performs, for example, a process of identifying characteristic regions and characteristic positions in the anterior segment image.

For example, the analysis unit 231 can identify a predetermined region including a region corresponding to the pupil of the subject's eye E in the anterior segment image as a characteristic region. The tracking control section 211B controls the optical system driving section 1A based on the displacement of the characteristic region in the target image with respect to the characteristic region in the base image. Thereby, tracking based on the position of the characteristic region can be performed. The characteristic region may be a blood vessel, a diseased part, an iris region, or the like.

Further, by analyzing the base image and the target image, the analysis unit 231 can detect occurrence of factors that hinder tracking control, such as movement of the subject's eye E and occurrence of blinking. For example, when the movement amount of the feature region in the target image with respect to the feature region in the base image is equal to or greater than a predetermined first threshold, the analysis unit 231 determines that the movement amount of the subject's eye E is large, and detects it as an abnormal state that hinders tracking control. When the analysis unit 231 cannot specify (detect) a predetermined characteristic region in at least one of the base image and the target image, the analysis unit 231 determines that the eyelids are closed due to blinking, and detects it as an abnormal state that hinders tracking control. In addition, when at least part of the boundary of the characteristic region (for example, the pupil region) cannot be specified (detected) in at least one of the base image and the target image, the analysis unit 231 determines that the eyelashes are covered, and detects an abnormal state that hinders tracking control.

(fundus mode)
In the fundus mode, the analysis unit 231 performs, for example, a process of specifying a characteristic region or a characteristic position in the fundus image.

For example, the analysis unit 231 can identify a predetermined region including a region corresponding to the optic papilla and the fovea in the fundus image as a feature region. The tracking control section 211B controls the optical system driving section 1A based on the displacement of the characteristic region in the target image with respect to the characteristic region in the base image. Thereby, tracking based on the position of the characteristic region can be performed. A feature region may be a blood vessel, a diseased part, or the like.

Further, as in the anterior segment mode, the analysis unit 231 analyzes the base image and the target image to detect the movement of the eye E to be inspected, the occurrence of blinking, the occurrence of flare, and other factors that hinder tracking control. For example, when the amount of movement of the feature region in the target image with respect to the feature region in the base image is equal to or greater than a predetermined second threshold, the analysis unit 231 determines that the amount of movement of the subject's eye E is large, and detects it as an abnormal state that hinders tracking control. Also, the analysis unit 231 can identify (detect) a predetermined characteristic region by analyzing the luminance distribution (luminance information) of at least one of the base image and the target image. For example, when the brightness of the entire image is high (at a predetermined threshold level or higher), the analysis unit 231 determines that the eyelids are closed due to blinking, and detects this as an abnormal state that hinders tracking control. For example, when the brightness of the entire image is low (below a predetermined threshold level), the analysis unit 231 determines that eyelashes are drawn, and detects an abnormal state that hinders tracking control. For example, when there is a partial area with high brightness, the analysis unit 231 determines that flare has occurred in the image, and detects it as an abnormal state that hinders tracking control.

The data processing unit 230 that functions as described above includes, for example, a microprocessor, RAM, ROM, hard disk drive, circuit board, and the like. A storage device such as a hard disk drive pre-stores a computer program that causes a microprocessor to perform the functions described above.

(user interface)
The user interface 240 includes a display section 240A and an operation section 240B. The display section 240A includes the display device of the arithmetic control unit 200 and the display device 3 described above. The operation section 240B includes the operation device of the arithmetic control unit 200 described above. The operation unit 240B may include various buttons and keys provided on the housing of the ophthalmologic apparatus 1 or on the outside. Moreover, the display section 240A may include various display devices such as a touch panel provided in the housing of the retinal camera unit 2 .

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

The optical system (for example, the interference optical system included in the OCT unit 100) shown in FIG. 1 is an example of the "optical system" according to the embodiment. The optical system driving section 1A is an example of a "moving mechanism" according to the embodiment. The imaging optical system 30 is an example of an "image acquisition section" according to the embodiment. The analysis unit 231 is an example of an "abnormality detection unit" according to the embodiment. A base image is an example of a "reference image" according to an embodiment. The target image is an example of "the image of the subject's eye acquired by the image acquiring unit" according to the embodiment.

[Example of operation]
An operation example of the ophthalmologic apparatus according to the embodiment will be described.

FIG. 5 shows a flowchart representing an example of the operation of the ophthalmologic apparatus 1 according to the embodiment. In FIG. 8, it is assumed that the front lens 23 is arranged between the subject's eye E and the objective lens 22 .

(S1: Start imaging the anterior segment)
First, acquisition of a near-infrared moving image of the anterior segment is started by continuously illuminating the anterior segment with illumination light from the observation light source 11 (which becomes near-infrared light by the visible cut filter 14). This near-infrared moving image is obtained in real time until the continuous illumination ends. The images of each frame constituting this moving image are temporarily stored in a frame memory (storage unit 212) and sequentially sent to the data processing unit 230. FIG.

An alignment target by the alignment optical system 50 and a split target by the focus optical system 60 are projected onto the eye E to be examined. Therefore, an alignment target and a split target are drawn on the near-infrared moving image. Alignment and focusing can be performed using these targets. A fixation target by the LCD 39 is also projected onto the eye E to be examined. The subject is instructed to gaze at this fixation target.

(S2: Alignment)
The data processing unit 230 successively analyzes frames obtained by capturing moving images of the subject's eye E using the optical system, obtains the position of the target image based on the alignment target, and calculates the amount of movement of the optical system. The control unit 210 performs auto-alignment by controlling the optical system driving unit 1A based on the amount of movement of the optical system calculated by the data processing unit 230 .

(S3: Focusing)
The data processing unit 230 sequentially analyzes the frames obtained by capturing the moving image of the subject's eye E using the optical system, obtains the position of the split target, and calculates the amount of movement of the imaging focusing lens 31 and the OCT focusing lens 43 . The control unit 210 performs autofocus by controlling the focus driving units 31A and 43A based on the movement amounts of the imaging focusing lens 31 and the OCT focusing lens 43 calculated by the data processing unit 230 .

(S4: Start tracking)
Subsequently, control unit 210 starts auto-tracking. Specifically, the data processing unit 230 analyzes in real time frames successively obtained by capturing moving images of the subject's eye E using an optical system, and monitors the movement (change in position) of the subject's eye E. FIG. The control unit 210 controls the optical system driving unit 1A so as to move the optical system in accordance with the positions of the eye E to be examined that are sequentially obtained. As a result, the optical system can follow the movement of the subject's eye E in real time, and a suitable positional relationship in which alignment and focus are achieved can be maintained.

(S5: Set scan area)
Control unit 210 causes display unit 240A to display the near-infrared moving image in real time. The user sets a scan area on this near-infrared moving image by using the operation unit 240B. The set scan area may be a one-dimensional area or a two-dimensional area.

(S6: OCT measurement)
The control unit 210 controls the light source unit 101 and the optical path length changing unit 41, and controls the optical scanner 42 based on the scan region set in step S5, thereby performing OCT measurement of the anterior segment. The image forming unit 220 forms a tomographic image of the anterior segment based on the obtained detection signal. When the scanning mode is three-dimensional scanning, the data processing section 230 forms a three-dimensional image of the anterior segment based on a plurality of tomographic images formed by the image forming section 220 . Note that when an abnormal state that hinders tracking control is detected as described above, the control unit 210 causes rescanning to be performed. Thereby, the influence on image acquisition and measurement can be reduced. This completes the operation example (end).

FIG. 6 shows a flow chart of an example of processing in step S6 of FIG. In FIG. 6, it is assumed that an anterior segment image, which is a base image, has been acquired in advance.

(S11: Acquire image)
First, the control unit 210 acquires an anterior segment image as a target image using the imaging optical system 30 .

(S12: Analysis)
Subsequently, the control unit 210 causes the analysis unit 231 to analyze the anterior eye image as the base image that has already been acquired and the anterior eye image acquired in step S11, thereby detecting whether or not there is an abnormal state that hinders the tracking control as described above.

(S13: Abnormality detected?)
When an abnormal state is detected by the analysis processing in step S12 (S13: Y), the operation of the ophthalmologic apparatus 1 proceeds to step S14. When the analysis processing in step S12 detects that there is no abnormal condition (S13: N), the operation of the ophthalmologic apparatus 1 proceeds to step S17.

(S14: Alignment)
When an abnormal state is detected in step S13 (S13: Y), the controller 210 performs alignment in the same manner as in step S2. As a result, the positional relationship of the apparatus optical system with respect to the subject's eye E becomes substantially the same as after the alignment in step S2 is completed.

(S15: Reset optical scanner)
Subsequently, the control unit 210 resets the optical scanner 42 so as to project the measurement light LS to the start position of the first scan being executed at the image acquisition timing in step S11 or the second scan executed before the first scan.

(S16: Start rescanning)
Next, the control unit 210 re-executes the first scan or the second scan from the start position reset in step S15.

(S17: calculate displacement)
When it is detected that there is no abnormal condition in step S13 (S13: N), the control unit 210 causes the analysis unit 231 to calculate the displacement of the feature region in the anterior eye image as the base image that has already been acquired and the feature region in the anterior eye image acquired in step S11.

(S18: movement control)
The control unit 210 causes the apparatus optical system to follow the movement of the eye E by controlling the optical system driving unit 1A based on the displacement calculated in step S17.

(S19: End of scanning?)
Following step S16 or step S18, control unit 210 determines whether or not scanning has ended. For example, the control unit 210 determines whether or not scanning is completed based on a preset scan area and scan pattern. When it is determined that scanning has ended (S19: Y), the operation of the ophthalmologic apparatus 1 proceeds to step S20. When it is determined that scanning is not finished (S19: N), the operation of the ophthalmologic apparatus 1 proceeds to step S11.

(S20: save)
When it is determined in step S19 that scanning has ended (S19: Y), the control unit 210 associates abnormality occurrence information including the cause of the abnormal state with the subject information and saves it in the storage unit 212 based on the abnormal state detection processing in step S13. As described above, the analysis unit 231 detects the movement of the subject's eye E or the occurrence of blinking as an abnormal state. The analysis unit 231 can generate abnormality occurrence information including occurrence cause information corresponding to the process in which the abnormal state is detected. The analysis unit 231 can generate abnormality occurrence information including occurrence cause information corresponding to the abnormal state when the same type of abnormal state is continuously detected a predetermined number of times during measurement of the subject. Note that step S20 may be executed at any position between steps S13 and S19. With this, the processing of step S6 is completed (end).

Note that FIG. 6 describes the case where the observation site is the anterior segment of the eye, but the same applies when the observation site is the fundus. In this case, the abnormal state is detected by the detection method corresponding to the fundus image as described above.

Further, the abnormality occurrence information stored in the storage unit 212 in step S20 of FIG. 6 may be used, for example, in rescanning or remeasurement of the subject in step S16 of FIG.

For example, when it is determined that line-of-sight deviation (movement of the subject's eye E) is likely to occur based on the abnormality occurrence information, the control unit 210 may control the LCD 39 to move the fixation position during rescanning or re-measurement of the subject in step S16, thereby suppressing the occurrence of line-of-sight deviation.

For example, when it is determined that blinking is likely to occur based on the abnormality occurrence information, the control unit 210 may specify the blinking cycle during rescanning in step S16 or during remeasurement of the subject, and may control the optical scanner 42 to perform scanning in synchronization with the specified cycle.

For example, when it is determined that the eyelashes are likely to be drawn in the image based on the abnormality occurrence information, the control unit 210 may cause the UI unit 240 to output information such as prompting the examiner to open the eyelids prior to rescanning or remeasurement of the subject.

For example, when it is determined that flare is likely to occur based on the abnormality occurrence information, the control unit 210 may control the optical system driving unit 1A so as to adjust the working distance prior to rescanning or remeasurement of the subject.

[effect]
An ophthalmologic apparatus according to an embodiment will be described.

The ophthalmologic apparatus (1) according to the embodiment includes an optical system (the optical system shown in FIG. 1, an interference optical system included in the OCT unit 100), a moving mechanism (optical system driving unit 1A), an image acquisition unit (imaging optical system 30), an abnormality detection unit (analysis unit 231), a scan control unit (211C), and a tracking control unit (211B). The optical system includes an optical scanner (42), which deflects light (L0) from the light source (light source unit 101) by the optical scanner and projects it onto the subject's eye (E), and receives light based on return light from the subject's eye (interference light LC, part of the return light). The movement mechanism relatively moves the subject's eye and the optical system. The image acquisition unit acquires an image of the subject's eye. The abnormality detection unit detects an abnormality (abnormal state) based on the reference image (base image) and the image of the subject's eye (target image) acquired by the image acquisition unit. When an abnormality is detected by the abnormality detection section, the scan control section controls the optical scanner so as to project light from the light source to the start position of the first scan being performed for the eye to be inspected at the image acquisition timing or the second scan performed before the first scan, and re-execute the first scan or the second scan. The tracking control unit controls the movement mechanism so that the optical system follows the movement of the subject's eye based on the reference image and the image of the subject's eye when the abnormality is not detected by the abnormality detector.

According to such a configuration, an abnormality is detected during tracking control based on the reference image and the image of the eye to be inspected acquired by the image acquisition unit, and the first scan or the second scan that is being performed for the eye to be inspected is re-executed at the acquisition timing of the image of the eye to be inspected. Therefore, even if a factor that hinders the tracking control occurs during the tracking control, it is possible to obtain an accurate image and reduce the influence on the measurement with simple control.

Further, the ophthalmologic apparatus according to the embodiment may include an alignment controller (211A) that executes alignment of the optical system with respect to the subject's eye by controlling the movement mechanism when an abnormality is detected, and the scan controller may re-execute the first scan or the second scan after the alignment by the alignment controller is completed.

According to such a configuration, since the first scan or the second scan is re-executed after the completion of the alignment, the data obtained before the re-scanning and the data obtained by the re-executed scanning are consistent, and it is possible to contribute to accurate image acquisition and measurement.

Further, in the ophthalmologic apparatus according to the embodiment, the image acquisition unit may acquire an anterior segment image of the subject's eye, and the tracking control unit may control the movement mechanism based on the amount of deviation between the feature positions in the reference image and the anterior segment image.

According to such a configuration, even when the subject's eye moves during tracking control based on the anterior segment image, it is possible to reduce the influence on accurate image acquisition and measurement with simple control.

Further, in the ophthalmologic apparatus according to the embodiment, the abnormality detection unit may detect abnormality when the deviation amount of the characteristic position is equal to or greater than the first threshold.

According to such a configuration, even if the subject's eye moves with a large deviation of the characteristic position during tracking control based on the anterior segment image, it is possible to reduce the influence on accurate image acquisition and measurement with simple control.

Further, in the ophthalmologic apparatus according to the embodiment, the abnormality detection unit may detect an abnormality when the characteristic position is not detected in the reference image or the anterior segment image.

According to such a configuration, even when blinking occurs during tracking control based on the anterior segment image, it is possible to reduce the influence on accurate image acquisition and measurement with simple control.

Further, in the ophthalmologic apparatus according to the embodiment, the abnormality detection unit may detect an abnormality when at least part of the boundary of the characteristic region is not detected in the reference image or the anterior segment image.

According to such a configuration, even when the eyelashes are drawn in the image during tracking control based on the anterior segment image, it is possible to reduce the influence on accurate image acquisition and measurement with simple control.

Further, in the ophthalmologic apparatus according to the embodiment, the image acquisition unit may acquire a fundus image (target image) of the subject's eye, and the tracking control unit may control the movement mechanism so as to cancel the positional deviation amount obtained by performing phase-only correlation processing on the reference image and the fundus image.

According to such a configuration, even if the subject's eye moves during tracking control based on the fundus image, it is possible to reduce the influence on accurate image acquisition and measurement with simple control.

Further, in the ophthalmologic apparatus according to the embodiment, the abnormality detection unit may detect an abnormality when the characteristic position is not detected based on the luminance information of the reference image or the fundus image.

According to such a configuration, even if blinking or eyelashes are detected during tracking control based on the fundus image, it is possible to reduce the influence on accurate image acquisition and measurement with simple control.

Further, in the ophthalmologic apparatus according to the embodiment, the abnormality detection unit may detect an abnormality when flare is detected in the reference image or the fundus image.

According to such a configuration, even if the occurrence of flare is detected during tracking performance based on the fundus image, it is possible to reduce the influence on accurate image acquisition and measurement with simple control.

Further, the ophthalmologic apparatus according to the embodiment may include a control unit (210, main control unit 211) that, when an abnormality is detected by the abnormality detection unit, stores abnormality occurrence information including the cause of the abnormality in the storage unit (212) in association with subject information.

With such a configuration, it is possible to identify the cause of the occurrence of an abnormality during tracking control, so that measures can be taken to prevent the occurrence of the same abnormality when measuring the subject again.

Further, the method for controlling an ophthalmologic apparatus according to the embodiment includes an optical scanner (42) that deflects light (measurement light LS) from a light source (light source unit 101) by the optical scanner and projects the light (measurement light LS) onto an eye (E) to be examined, and receives light (interference light LC) based on light returned from the eye (optical system shown in FIG. 1, an interference optical system included in the OCT unit 100), and a moving mechanism (optical system driving unit 1A) that relatively moves the eye and the optical system. and a control method for an ophthalmologic apparatus. This ophthalmologic apparatus control method includes an image acquisition step, an abnormality detection step, a scan control step, and a tracking control step. The image acquisition step acquires an image of the subject's eye (target image). The abnormality detection step detects an abnormality based on the reference image (base image) and the image of the subject's eye. In the scan control step, when an abnormality is detected, the first scan or the second scan is performed again by controlling the optical scanner to project the light onto the start position of the first scan being performed on the eye to be inspected or the second scan performed before the first scan at the image acquisition timing. The tracking control step controls the moving mechanism so that the optical system follows the movement of the eye to be inspected based on the reference image and the image of the eye to be inspected when no abnormality is detected.

According to such a configuration, an abnormality is detected during tracking control based on the reference image and the image of the eye to be inspected acquired by the image acquiring unit, and the first scan or the second scan that is being performed is re-executed for the eye to be inspected at the image acquisition timing. Therefore, even if the eye to be inspected moves or blinks during tracking control, it is possible to obtain an accurate image and reduce the influence on the measurement with simple control.

Further, the method for controlling the ophthalmologic apparatus may include an alignment control step of performing alignment of the optical system with respect to the subject's eye by controlling the moving mechanism when an abnormality is detected, and the scan control step may re-execute the first scan or the second scan after the alignment in the alignment control step is completed.

According to such a configuration, since the first scan or the second scan is re-executed after the completion of the alignment, the data obtained before the re-scanning and the data obtained by the re-executed scanning are consistent, and it is possible to contribute to accurate image acquisition and measurement.

<Modification>
The embodiment shown above is merely an example for carrying out the present invention. A person who intends to implement this invention can make arbitrary modifications, omissions, additions, etc. within the scope of the gist of this invention.

In the above-described embodiments, the case where the configuration of the optical system is the configuration shown in FIG. 1 or 2 has been described, but the configuration of the optical system according to the embodiment is not limited to this. The optical system according to the embodiment may include an optical system for irradiating a treatment site on the fundus with laser light, an optical system for moving a target while the subject's eye is fixated, and the like.

In the above-described embodiment, the imaging site is the fundus or the anterior segment of the eye, but the imaging site is not limited to the fundus of the eye or the anterior segment of the eye. In addition, three or more parts may be imaged.

1 ophthalmic apparatus 1A optical system driving unit 10 illumination optical system 23 front lens 30 photographing optical system 35 CCD image sensor 100 OCT unit 210 control unit 211 main control unit 211A alignment control unit 211B tracking control unit 211C scan control unit 212 storage unit 220 image forming unit 230 data processing unit 231 analysis unit E eye to be examined

Claims (10)

an optical system that includes an optical scanner, deflects light from a light source by the optical scanner, projects the light onto an eye to be inspected, and receives light based on light returned from the eye to be inspected;
a movement mechanism that relatively moves the eye to be examined and the optical system;
an image acquisition unit that acquires an image of the eye to be inspected;
an abnormality detection unit that detects an abnormality based on the image of the eye to be inspected acquired by the image acquiring unit and a reference image of the eye to be inspected that is acquired prior to the image of the eye to be inspected and serves as a reference for detecting an abnormality;
an alignment control unit that, when an abnormality is detected by the abnormality detection unit, obtains the position of the target image based on the alignment target, calculates the amount of movement of the optical system based on the amount of deviation of the target image from the reference position, and controls the moving mechanism based on the calculated amount of movement ;
a scan control unit for re-executing the first scan or the second scan by controlling the optical scanner so as to project light from the light source to a start position of a first scan being performed on the eye to be inspected or a second scan performed prior to the first scan after the alignment control unit completes control of the moving mechanism ;
a tracking control unit that controls the moving mechanism so that the optical system follows the movement of the eye to be inspected based on the reference image and the image of the eye to be inspected when the abnormality detection unit does not detect an abnormality;
including
After re-executing the first scan or the second scan, the image acquisition unit re-acquire the image of the eye to be inspected, and the abnormality detection unit detects the abnormality using the reference image and the re-acquired image. The image acquisition unit acquires an anterior segment image of the eye to be examined,
The ophthalmologic apparatus according to claim 1, wherein the tracking control unit controls the moving mechanism based on a deviation amount of characteristic positions between the reference image and the anterior segment image. The ophthalmologic apparatus according to claim 2, wherein the abnormality detection unit detects the abnormality when the deviation amount of the characteristic position is equal to or greater than a first threshold. 4. The ophthalmologic apparatus according to claim 2, wherein the abnormality detection unit detects the abnormality when no feature point is detected in the reference image or the anterior segment image. The ophthalmologic apparatus according to any one of claims 2 to 4, wherein the abnormality detection unit detects the abnormality when at least part of a boundary of a characteristic region is not detected in the reference image or the anterior segment image. The image acquisition unit acquires a fundus image of the eye to be examined,
2. The ophthalmologic apparatus according to claim 1, wherein the tracking control unit controls the movement mechanism so as to cancel a positional deviation amount obtained by performing phase-only correlation processing on the reference image and the fundus image. The ophthalmologic apparatus according to claim 6, wherein the abnormality detection unit detects the abnormality based on luminance information of the reference image or the fundus image. 8. The ophthalmologic apparatus according to claim 6, wherein the abnormality detection unit detects the abnormality when flare is detected in the reference image or the fundus image. 9. The ophthalmologic apparatus according to any one of claims 1 to 8, further comprising a control unit that, when the abnormality is detected by the abnormality detection unit, stores abnormality occurrence information including the cause of the abnormality in a storage unit in association with subject information. an optical system that includes an optical scanner, deflects light from a light source by the optical scanner, projects the light onto an eye to be inspected, and receives light based on light returned from the eye to be inspected;
a movement mechanism that relatively moves the eye to be examined and the optical system;
A control method for an ophthalmic device comprising:
an image acquisition step of acquiring an image of the eye to be inspected;
an abnormality detection step of detecting an abnormality based on the image of the eye to be inspected and a reference image of the eye to be inspected that is obtained prior to the image of the eye to be inspected and serves as a reference for detecting an abnormality ;
an alignment control step of obtaining the position of the target image based on the alignment target when the abnormality is detected, calculating the amount of movement of the optical system based on the amount of deviation of the target image from the reference position, and controlling the moving mechanism based on the calculated amount of movement;
after the control of the moving mechanism in the alignment control step is completed, a scan control step of controlling the optical scanner to project the light from the light source to the start position of the first scan being performed on the eye to be inspected at the acquisition timing of the image of the eye to be inspected or the second scan performed before the first scan, and to re-execute the first scan or the second scan;
a tracking control unit step of controlling the moving mechanism so that the optical system follows the movement of the eye to be inspected based on the reference image and the image of the eye to be inspected when the abnormality is not detected;
including
After re-executing the first scan or the second scan, the image acquisition step re-acquires the image of the subject eye, and the abnormality detection step detects the abnormality using the reference image and the re-acquired image.

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