JP2012016620A - Fundus observation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fundus observation device, which allows effective and efficient follow-up using a tomographic image of fundus.SOLUTION: The fundus observation device includes an image forming means; a position information generation means; and an image processing means. The image forming means detects an interference light between a signal light and a reference light passed through the fundus of a subject eye, and forms a tomographic image in depth direction of the fundus based on the detection result. The position information generation means generates, based on the formed tomographic image, depth information indicating a position in depth direction of the tomographic image. The image processing means performs, based on depth information generated for a tomographic image formed first and depth information generated for a tomographic image formed subsequently, alignment in depth direction of the former tomographic image and the subsequent tomographic image.

Description

  The present invention relates to a fundus oculi observation device used for observing the fundus oculi of a subject eye.

  Conventionally, fundus cameras have been widely used as fundus oculi observation devices. FIG. 13 shows an example of the external configuration of a conventional general fundus camera, and FIG. 14 shows an example of the configuration of an optical system built in the fundus camera (see, for example, Patent Document 1). Note that “observation” includes at least a case where a photographed image of the fundus is observed (others may include fundus observation with the naked eye).

  First, an external configuration of a conventional fundus camera 1000 will be described with reference to FIG. The fundus camera 1000 includes a gantry 3 mounted on a base 2 so as to be slidable in the front-rear and left-right directions (horizontal direction). The gantry 3 is provided with an operation panel 3a and a joystick 4 for the examiner to perform various operations.

  The examiner can move the gantry 3 three-dimensionally on the base 2 by operating the joystick 4. On the top of the joystick 4, an operation button 4a that is pressed when photographing the fundus is disposed.

  A support column 5 is erected on the base 2. The column 5 is provided with a chin rest 6 for mounting the subject's jaw and an external fixation lamp 7 for emitting light for fixing the eye E.

  On the gantry 3, a main body 8 that stores various optical systems and control systems of the fundus camera 1000 is mounted. The control system may be provided inside the base 2 or the gantry 3 or may be provided in an external device such as a computer connected to the fundus camera 1000.

  On the eye E side of the main body 8 (the left direction in FIG. 13), an objective lens unit 8a is provided so as to face the eye E. Further, an eyepiece 8b for observing the fundus of the eye E to be examined with the naked eye is provided on the examiner side of the main body 8 (the right direction in FIG. 13).

  Further, the main body 8 is provided with a still camera 9 for capturing a still image of the fundus of the eye E and an imaging device 10 such as a television camera for capturing a still image or a moving image of the fundus. Yes. The still camera 9 and the imaging device 10 are detachably attached to the main body 8.

  As the still camera 9, a digital camera equipped with an image sensor such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS), or a film camera, depending on various conditions such as the purpose of inspection and the method of storing a captured image In addition, an instant camera or the like can be appropriately attached and used. The main body portion 8 is formed with a mounting portion 8c for selectively mounting such various still cameras 9.

  When the still camera 9 or the imaging device 10 is of a digital imaging system, the image data of the fundus image captured by the still camera 9 or the imaging device 10 is transmitted to a computer or the like connected to the fundus camera 1000, and the fundus image is displayed on the display. Can be observed. Further, the image data can be transmitted to an image recording apparatus connected to the fundus camera 1000 to form a database and used as electronic data for creating an electronic medical chart, for example.

  A touch panel monitor 11 is provided on the examiner side of the main body 8. On the touch panel monitor 11, a fundus image of the eye E to be examined that is created based on a video signal output from the (digital type) still camera 9 or the imaging device 10 is displayed. On the touch panel monitor 11, a two-dimensional coordinate system having the origin at the center of the screen is displayed superimposed on the fundus image. When the examiner touches a desired position on the screen, a coordinate value corresponding to the touched position is displayed.

  Next, the configuration of the optical system of the fundus camera 1000 will be described with reference to FIG. The fundus camera 1000 is provided with an illumination optical system 100 that illuminates the fundus oculi Ef of the eye E, and an imaging optical system 120 that guides the fundus reflection light of the illumination light to the eyepiece unit 8b, the still camera 9, and the imaging device 10. It has been.

  The illumination optical system 100 includes an observation light source 101, a condenser lens 102, a photographing light source 103, a condenser lens 104, exciter filters 105 and 106, a ring translucent plate 107, a mirror 108, an LCD 109, an illumination diaphragm 110, a relay lens 111, and a perforated mirror. 112 and an objective lens 113 are included.

  The observation light source 101 is constituted by a halogen lamp, for example, and outputs steady light (continuous light) for fundus observation. The condenser lens 102 is an optical element that collects steady light (observation illumination light) emitted from the observation light source 101 and illuminates the observation illumination light almost evenly on the fundus.

  The imaging light source 103 is composed of, for example, a xenon lamp, and emits flash light when imaging the fundus oculi Ef. The condenser lens 104 is an optical element that collects flash light (imaging illumination light) emitted from the imaging light source 103 and uniformly irradiates the fundus oculi Ef with the imaging illumination light.

  The exciter filters 105 and 106 are filters used when performing fluorescence imaging of a fundus image of the fundus oculi Ef. Each of the exciter filters 105 and 106 can be inserted into and removed from the optical path by a drive mechanism (not shown) such as a solenoid. The exciter filter 105 is disposed on the optical path during FAG (fluorescein fluorescence imaging) imaging. On the other hand, the exciter filter 106 is disposed on the optical path during ICG (Indocyanine Green Fluorescence Imaging) imaging. Note that the exciter filters 105 and 106 are both retracted from the optical path during color photographing.

  The ring translucent plate 107 is disposed at a position conjugate with the pupil of the eye E to be examined, and includes a ring translucent portion 107 a centering on the optical axis of the illumination optical system 100. The mirror 108 reflects the illumination light emitted from the observation light source 101 and the photographing light source 103 in the optical axis direction of the photographing optical system 120. The LCD 109 displays a fixation target (not shown) for fixing the eye E to be examined.

  The illumination stop 110 is a stop member that blocks part of the illumination light for preventing flare and the like. The illumination stop 110 is configured to be movable in the optical axis direction of the illumination optical system 100, thereby adjusting the illumination area of the fundus oculi Ef.

  The aperture mirror 112 is an optical element that combines the optical axis of the illumination optical system 100 and the optical axis of the photographing optical system 120. A hole 112 a is opened in the center region of the perforated mirror 112. The optical axis of the illumination optical system 100 and the optical axis of the photographing optical system 120 intersect at a substantially central position of the hole 112a. The objective lens 113 is provided in the objective lens portion 8 a of the main body portion 8.

  The illumination optical system 100 having such a configuration illuminates the fundus oculi Ef in the following manner. First, at the time of fundus observation, the observation light source 101 is turned on and observation illumination light is output. This observation illumination light irradiates the ring translucent plate 107 through the condenser lenses 102 and 104 (the exciter filters 105 and 106 are retracted from the optical path). The light that has passed through the ring translucent portion 107 a of the ring translucent plate 107 is reflected by the mirror 108 and reflected by the perforated mirror 112 via the LCD 109, the illumination stop 110, and the relay lens 111. The observation illumination light reflected by the aperture mirror 112 travels in the optical axis direction of the imaging optical system 120, is focused by the objective lens 113, and enters the eye E to illuminate the fundus oculi Ef.

  At this time, since the ring translucent plate 107 is disposed at a position conjugate to the pupil of the eye E, a ring-shaped image of observation illumination light incident on the eye E is formed on the pupil. The fundus reflection light of the observation illumination light is emitted from the eye E through the central dark part of the ring-shaped image on the pupil. In this manner, the influence of the observation illumination light incident on the eye E on the fundus reflection light of the observation illumination light is prevented.

  On the other hand, when photographing the fundus oculi Ef, the photographing light source 103 emits flash light, and the photographing illumination light is irradiated onto the fundus oculi Ef through a similar route. In the case of fluorescent photographing, the exciter filter 105 or 106 is selectively arranged on the optical path depending on whether FAG photographing or ICG photographing.

  Next, the photographing optical system 120 will be described. The photographing optical system 120 includes an objective lens 113, a perforated mirror 112 (hole 112a), a photographing aperture 121, barrier filters 122 and 123, a variable power lens 124, a relay lens 125, a photographing lens 126, a quick return mirror 127, and a photographing. The medium 9a is included. Here, the imaging medium 9a is an arbitrary imaging medium (an imaging element such as a CCD, a camera film, an instant film, etc.) used for the still camera 9.

  The fundus reflection light of the illumination light emitted from the eye E through the central dark part of the ring-shaped image on the pupil enters the photographing aperture 121 through the hole 112a of the aperture mirror 112. The perforated mirror 112 reflects the corneal reflection light of the illumination light and acts so as not to mix the corneal reflection light into the fundus reflection light incident on the photographing aperture 121. Thereby, the occurrence of flare in the observed image or the photographed image is suppressed.

  The photographing aperture 121 is a plate-like member in which a plurality of circular translucent portions having different sizes are formed. The plurality of light-transmitting portions constitute diaphragms having different aperture values (F values), and the light-transmitting portions are alternatively arranged on the optical path by a driving mechanism (not shown).

  Each of the barrier filters 122 and 123 can be inserted into and removed from the optical path by a drive mechanism (not shown) such as a solenoid. When performing FAG imaging, the barrier filter 122 is disposed on the optical path, and when performing ICG imaging, the barrier filter 123 is disposed on the optical path. When performing color photography, both the barrier filters 122 and 123 are retracted from the optical path.

  The variable magnification lens 124 can be moved in the optical axis direction of the photographing optical system 120 by a driving mechanism (not shown). Thereby, it is possible to change the observation magnification and the imaging magnification, focus the fundus image, and the like. The photographing lens 126 is a lens that forms an image of fundus reflected light from the eye E on the photographing medium 9a.

  The quick return mirror 127 is rotatably provided around the rotation shaft 127a by a driving mechanism (not shown). When photographing the fundus oculi Ef with the still camera 9, the fundus reflected light is guided to the photographing medium 9a by jumping up the quick return mirror 127 obliquely provided on the optical path. On the other hand, when photographing the fundus with the imaging device 10 or observing the fundus with the examiner's naked eye, the fundus reflected light is reflected upward with the quick return mirror 127 obliquely arranged on the optical path. Yes.

  The photographing optical system 120 further includes a field lens (field lens) 128, a switching mirror 129, an eyepiece lens 130, a relay lens 131, a reflection mirror 132, for guiding the fundus reflection light reflected by the quick return mirror 127. A photographing lens 133 and an image sensor 10a are provided. The imaging element 10 a is an imaging element such as a CCD built in the imaging apparatus 10. On the touch panel monitor 11, a fundus oculi image Ef ′ photographed by the image sensor 10a is displayed.

  As with the quick return mirror 127, the switching mirror 129 is rotatable around the rotation shaft 129a. The switching mirror 129 reflects the fundus reflection light toward the eyepiece lens 130 while being obliquely provided on the optical path during observation with the naked eye.

  Further, when a fundus image is captured using the imaging device 10, the switching mirror 129 is retracted from the optical path to guide the fundus reflection light toward the imaging element 10a. In this case, the fundus reflection light is reflected by the mirror 132 via the relay lens 131 and imaged on the image sensor 10 a by the photographing lens 133.

  Such a fundus camera 1000 is a fundus oculi observation device used for observing the surface of the fundus oculi Ef, that is, the state of the retina. In other words, the fundus camera 1000 is a device for obtaining a two-dimensional fundus image when the fundus oculi Ef is viewed from the cornea direction of the eye E to be examined. On the other hand, there are tissues such as the choroid and sclera in the deep layer of the retina, and a technique for observing the state of these tissues has been desired. In recent years, a device for observing these deep tissues has been put into practical use. (For example, see Patent Documents 2 and 3).

  The fundus oculi observation device disclosed in Patent Documents 2 and 3 is a device (referred to as an optical image measurement device, an optical coherence topography device, or the like) that applies so-called OCT (Optical Coherence Tomography) technology. This fundus observation device bisects low-coherence light, guides one (signal light) to the fundus, guides the other (reference light) to a predetermined reference object, and passes the signal light and reference object through the fundus The apparatus forms a tomographic image of the fundus surface or deep tissue by detecting and analyzing interference light obtained by superimposing the reference light. Further, the optical image measurement device can form a three-dimensional image of the fundus oculi based on a plurality of tomographic images. Note that the optical image measurement device described in Patent Literature 2 is generally called a Fourier domain (Fourier Domain) OCT or the like.

  The Fourier domain OCT forms a tomographic image having a cross section in the depth direction along the scanning line by scanning the signal light and irradiating the fundus. Such scanning of signal light is called B scan or the like (for example, see Non-Patent Document 1).

  In the case of forming a three-dimensional image, a B-scan is executed along a plurality of scanning lines, and three-dimensional image data is generated by performing interpolation processing on the plurality of tomographic images obtained thereby. This three-dimensional image data is called volume data or voxel data as in the case of a medical image diagnostic apparatus such as an X-ray CT apparatus. Pixel data (brightness, shading, color, etc.) is stored in each voxel arranged three-dimensionally. (Brightness values, RGB values, etc.) are assigned to the image data. The three-dimensional image is displayed as a pseudo three-dimensional image viewed from a predetermined viewing direction obtained by rendering the volume data.

JP 2004-350849 A JP 2003-543 A Japanese Patent Laying-Open No. 2005-241464

NEDO Workshop “Human Body“ Window ”, Viewing the Body from the Fundus (Diagnosis)” -Development of ultra-early diagnostic equipment for lifestyle-related diseases using the latest optical technology- (Date: April 25, 2005), Internet < URL: http: // www. nedo. go. jp / informations / koubo / 170627_2 / besshi3. pdf>

  Follow-up observations for diagnosing the progress of wounds and treatment effects and the like are widely performed not only in ophthalmology but in the whole medical field. In follow-up observation, a plurality of inspections are performed over a predetermined period, and the inspection results are compared to make a diagnosis. In follow-up observation, there are many cases where an image of a site of interest such as an affected area is acquired over a predetermined period, and the temporal change of the site of interest is confirmed by comparing the images.

  In follow-up observation using images, it is necessary to acquire an image of the same part a plurality of times. However, in a fundus examination using a conventional fundus observation device, it is difficult to acquire an image of the same part. That is, in order to acquire an image of the same part at each examination date and time, the eye E to be examined must be fixed in the same direction, which is difficult. Moreover, the direction of the eye to be changed due to eye movement or pulsation due to blood flow is also a factor that makes it difficult to obtain an image of the same part.

  In particular, when comparing tomographic images of the fundus acquired by the optical image measurement device, it is difficult to determine from the images whether or not these tomographic images correspond to the same region (same cross section) of the fundus. It was. In addition, it is difficult to acquire a tomographic image having the same cross section as that of a tomographic image acquired in the past. For these reasons, it is difficult to effectively and efficiently observe the fundus.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a fundus oculi observation device capable of effectively and efficiently performing follow-up observation using a fundus tomographic image. .

  In order to achieve the above object, a fundus oculi observation device according to a first aspect includes an image forming unit, a position information generating unit, and an image processing unit. The image forming means detects the interference light between the signal light and the reference light that has passed through the fundus of the eye to be examined, and forms a tomographic image of the fundus in the depth direction based on the detection result. The position information generation unit generates depth information indicating the position of the tomographic image in the depth direction based on the formed tomographic image. The image processing means calculates the depth between the previous tomographic image and the subsequent tomographic image based on the depth information generated for the previously formed tomographic image and the depth information generated for the subsequently formed tomographic image. Align in the direction.

  The invention according to claim 2 is the fundus oculi observation device according to claim 1, wherein the depth information indicates a position of a predetermined layer of the fundus in a tomographic image formed by the image forming unit. Including information expressed by coordinates set in advance on the tomographic image, and the image processing means matches the coordinates corresponding to the previous tomographic image with the coordinates corresponding to the subsequent tomographic image. The previous tomographic image and the subsequent tomographic image are aligned in the depth direction.

  The fundus oculi observation device according to the present invention detects an interference light between the signal light and the reference light that has passed through the fundus of the subject's eye, and forms a tomographic image in the depth direction of the fundus based on the detection result; Position information generating means for generating depth information indicating the position of the tomographic image in the depth direction based on the formed tomographic image, depth information generated for the previously formed tomographic image, and a tomographic image formed thereafter Image processing means for aligning the previous tomographic image and the subsequent tomographic image in the depth direction based on the depth information generated for the image is provided. According to the present invention as described above, it is possible to suitably perform alignment in the depth direction between the previous tomographic image and the subsequent tomographic image having different examination dates and times, so that the follow-up observation using the tomographic image of the fundus is effectively performed. And can be performed efficiently.

It is a schematic block diagram showing an example of the whole structure of suitable embodiment of the fundus oculi observation device concerning the present invention. It is a schematic block diagram showing an example of a structure of the scanning unit incorporated in the fundus camera unit in a preferred embodiment of the fundus oculi observation device according to the present invention. It is a schematic block diagram showing an example of a structure of the OCT unit in suitable embodiment of the fundus oculi observation device concerning the present invention. It is a schematic block diagram showing an example of the hardware constitutions of the calculation control apparatus in suitable embodiment of the fundus oculi observation device concerning the present invention. It is a schematic block diagram showing an example of the structure of the control system of suitable embodiment of the fundus oculi observation device concerning the present invention. It is the schematic showing an example of the external appearance structure of the operation panel in suitable embodiment of the fundus oculi observation device concerning the present invention. It is a schematic block diagram showing an example of a structure of the arithmetic and control unit in suitable embodiment of the fundus oculi observation device concerning the present invention. It is the schematic showing an example of the scanning aspect of the signal light by suitable embodiment of the fundus oculi observation device concerning the present invention. FIG. 8A shows an example of a scanning mode of signal light when the fundus is viewed from the signal light incident side with respect to the eye to be examined. FIG. 8B shows an example of an arrangement mode of scanning points on each scanning line. It is the schematic showing an example of the scanning aspect of the signal light by the suitable embodiment of the fundus oculi observation device concerning the present invention, and the aspect of the tomographic image formed along each scanning line. It is a flowchart showing an example of operation | movement of suitable embodiment of the fundus oculi observation device concerning the present invention. It is the schematic showing an example of the screen displayed by suitable embodiment of the fundus oculi observation device concerning the present invention. It is a flowchart showing an example of operation | movement of suitable embodiment of the fundus oculi observation device concerning the present invention. It is a schematic side view showing an example of the appearance composition of the conventional fundus oculi observation device (fundus camera). It is the schematic showing an example of the internal structure (structure of an optical system) of the fundus observation apparatus (fundus camera) in the past.

  An example of a preferred embodiment of a fundus oculi observation device according to the present invention will be described in detail with reference to the drawings. Note that the same reference numerals as those in FIGS. 13 and 14 are used for the same components as in the prior art.

  First, the structure of the fundus oculi observation device according to the present embodiment will be described with reference to FIGS. FIG. 1 shows an example of the entire configuration of the fundus oculi observation device 1 according to the present embodiment. FIG. 2 shows an example of the configuration of the scanning unit 141 in the fundus camera unit 1A. FIG. 3 shows an example of the configuration of the OCT unit 150. FIG. 4 illustrates an example of a hardware configuration of the arithmetic control device 200. FIG. 5 shows an example of the configuration of the control system of the fundus oculi observation device 1. FIG. 6 shows an example of the configuration of the operation panel 3a provided in the fundus camera unit 1A. FIG. 7 shows an example of the configuration of the control system of the arithmetic and control unit 200.

[overall structure]
As shown in FIG. 1, a fundus oculi observation device 1 includes a fundus camera unit 1A that functions as a fundus camera, an OCT unit 150 that stores an optical system of an optical image measurement device (OCT device), and various arithmetic processes and control processes. Etc., and an arithmetic and control unit 200 that executes the above.

  One end of a connection line 152 is attached to the OCT unit 150. A connector portion 151 is attached to the other end of the connection line 152. The connector portion 151 is attached to the attachment portion 8c shown in FIG. In addition, an optical fiber is conducted inside the connection line 152. The OCT unit 150 and the fundus camera unit 1A are optically connected via a connection line 152. The detailed configuration of the OCT unit 150 will be described later with reference to FIG.

[Configuration of fundus camera unit]
The fundus camera unit 1A is a device that forms a two-dimensional image of the surface of the fundus of the subject's eye based on optically acquired data (data detected by the imaging devices 10 and 12), as shown in FIG. The external appearance is almost the same as that of the conventional fundus camera 1000. Similarly to the conventional optical system shown in FIG. 14, the fundus camera unit 1 </ b> A illuminates the fundus oculi Ef of the eye E to be examined, and photographing that guides the fundus reflection light of the illumination light to the imaging device 10. And an optical system 120.

  In addition, although mentioned later for details, the imaging device 10 in the imaging | photography optical system 120 of this embodiment detects the illumination light which has a wavelength of a near infrared region. The photographing optical system 120 is separately provided with an imaging device 12 for detecting illumination light having a wavelength in the visible region. Further, the photographing optical system 120 guides the signal light from the OCT unit 150 to the fundus oculi Ef and guides the signal light passing through the fundus oculi Ef to the OCT unit 150.

  The illumination optical system 100 includes an observation light source 101, a condenser lens 102, a photographing light source 103, a condenser lens 104, exciter filters 105 and 106, a ring translucent plate 107, a mirror 108, an LCD 109, an illumination stop 110, as in the conventional case. A relay lens 111, a perforated mirror 112, and an objective lens 113 are included.

  The observation light source 101 outputs illumination light having a wavelength in the visible region included in the range of about 400 nm to 700 nm. The imaging light source 103 outputs illumination light having a wavelength in the near infrared region included in a range of about 700 nm to 800 nm. The near-infrared light output from the imaging light source 103 is set to be shorter than the wavelength of light used in the OCT unit 150 (described later).

  The photographing optical system 120 includes an objective lens 113, a perforated mirror 112 (hole 112a), a photographing aperture 121, barrier filters 122 and 123, a variable power lens 124, a relay lens 125, a photographing lens 126, a dichroic mirror 134, Field lens (field lens) 128, half mirror 135, relay lens 131, dichroic mirror 136, photographing lens 133, imaging device 10 (imaging device 10a), reflection mirror 137, photographing lens 138, photographing device 12 (imaging device 12a), A lens 139 and an LCD (Liquid Crystal Display) 140 are included.

  In the photographing optical system 120 according to the present embodiment, unlike the conventional photographing optical system 120 shown in FIG. 14, the dichroic mirror 134, the half mirror 135, the dichroic mirror 136, the reflection mirror 137, the photographing lens 138, the lens 139, and the LCD 140. Is provided.

  The dichroic mirror 134 reflects the fundus reflection light (having a wavelength included in the range of about 400 nm to 800 nm) of the illumination light from the illumination optical system 100 and the signal light LS (about 800 nm to 900 nm of the OCT unit 150). It is configured to transmit light having a wavelength included in the range;

  Further, the dichroic mirror 136 transmits illumination light having a wavelength in the visible region from the illumination optical system 100 (visible light having a wavelength of about 400 nm to 700 nm output from the observation light source 101) and changes the wavelength in the near infrared region. It is configured to reflect the illumination light it has (near infrared light with a wavelength of about 700 nm to 800 nm output from the imaging light source 103).

  On the LCD 140, an internal fixation target or the like is displayed. The light from the LCD 140 is collected by the lens 139, reflected by the half mirror 135, and then reflected by the dichroic mirror 136 via the field lens 128. Then, the light enters the eye E through the photographing lens 126, the relay lens 125, the variable power lens 124, the aperture mirror 112 (the aperture 112 a), the objective lens 113, and the like. Thereby, an internal fixation target or the like is projected onto the fundus oculi Ef of the eye E to be examined.

  The image pickup device 10a is an image pickup device such as a CCD or a CMOS built in the image pickup device 10 such as a television camera, and particularly detects light having a wavelength in the near infrared region (that is, the image pickup device 10 is It is an infrared TV camera that detects near-infrared light.) The imaging device 10 outputs a video signal as a result of detecting near infrared light. The touch panel monitor 11 displays a two-dimensional image (fundus image Ef ′) of the surface of the fundus oculi Ef based on this video signal. The video signal is sent to the arithmetic and control unit 200, and a fundus image is displayed on the display (described later). At the time of fundus photographing by the imaging apparatus 10, for example, illumination light having a wavelength in the near infrared region output from the photographing light source 103 of the illumination optical system 100 is used.

  On the other hand, the image pickup device 12a is an image pickup device such as a CCD or a CMOS built in the image pickup device 12 such as a TV camera, and particularly detects light having a wavelength in the visible region (that is, the image pickup device 12 is TV camera that detects visible light.) The imaging device 12 outputs a video signal as a result of detecting visible light. The touch panel monitor 11 displays a two-dimensional image (fundus image Ef ′) of the surface of the fundus oculi Ef based on this video signal. The video signal is sent to the arithmetic and control unit 200, and a fundus image is displayed on the display (described later). At the time of fundus photographing by the imaging device 12, for example, illumination light having a visible region wavelength output from the observation light source 101 of the illumination optical system 100 is used.

  The photographing optical system 120 of the present embodiment is provided with a scanning unit 141 and a lens 142. The scanning unit 141 has a configuration that scans light (signal light LS; described later) output from the OCT unit 150 on the fundus oculi Ef.

  The lens 142 makes the signal light LS guided from the OCT unit 150 through the connection line 152 enter the scanning unit 141 as a parallel light beam. The lens 142 acts to focus the fundus reflection light of the signal light LS that has passed through the scanning unit 141.

  FIG. 2 shows an example of a specific configuration of the scanning unit 141. The scanning unit 141 includes galvanometer mirrors 141A and 141B and reflection mirrors 141C and 141D.

  The galvanometer mirrors 141A and 141B are rotatable about the rotation shafts 141a and 141b, respectively. The rotating shafts 141a and 141b are disposed so as to be orthogonal to each other. In FIG. 2, the rotation shaft 141a of the galvano mirror 141A is arranged in a direction parallel to the paper surface of FIG. 2, and the rotation shaft 141b of the galvano mirror 141B is orthogonal to the paper surface of FIG. Arranged in the direction. That is, the galvano mirror 141B is configured to be rotatable in a direction indicated by a double-sided arrow in FIG. 2, and the galvano mirror 141A is configured to be rotatable in a direction orthogonal to the double-sided arrow. Accordingly, the pair of galvanometer mirrors 141A and 141B act so as to change the reflection direction of the signal light LS to directions orthogonal to each other. In addition, each rotation operation | movement of the galvanometer mirror 141A, 141B is driven by the below-mentioned mirror drive mechanism (refer FIG. 5).

  The signal light LS reflected by the galvanometer mirrors 141A and 141B is reflected by the reflection mirrors 141C and 141D and travels in the same direction as when incident on the galvanometer mirror 141A.

  As described above, the optical fiber 152 a is electrically connected to the inside of the connection line 152, and the end surface 152 b of the optical fiber 152 a is disposed so as to face the lens 142. The signal light LS emitted from the end surface 152b travels toward the lens 142 while expanding the beam diameter, but is converted into a parallel light beam by the lens 142. On the contrary, the signal light LS passing through the fundus oculi Ef is focused toward the end surface 152b by the lens 142.

[Configuration of OCT unit]
Next, the configuration of the OCT unit 150 will be described with reference to FIG. An OCT unit 150 shown in the figure is an apparatus for forming a tomographic image of the fundus oculi based on data acquired by optical scanning (data detected by a CCD 184 described later), and is a conventional optical image measurement. Optical system almost the same as the device, that is, the light output from the light source is divided into reference light and signal light, and the reference light passing through the reference object and the signal light passing through the object to be measured (fundus Ef) are superimposed Thus, an interferometer that generates interference light and means for outputting a signal as a result of detecting the interference light to the arithmetic and control unit 200 are provided. The arithmetic and control unit 200 analyzes this signal and forms an image of the measured object (fundus Ef).

  The low coherence light source 160 is configured by a broadband light source such as a super luminescent diode (SLD) or a light emitting diode (LED) that outputs low coherence light L0. The low coherence light L0 is, for example, light having a wavelength in the near infrared region and a temporal coherence length of about several tens of micrometers. The low coherence light L0 output from the low coherence light source 160 has a wavelength longer than the illumination light (wavelength of about 400 nm to 800 nm) of the fundus camera unit 1A, for example, a wavelength included in a range of about 800 nm to 900 nm. . This low coherence light source 160 corresponds to an example of the “light source” of the present invention.

  The low coherence light L0 output from the low coherence light source 160 is guided to an optical coupler 162 through an optical fiber 161 made of, for example, a single mode fiber or a PM fiber (Polarization maintaining fiber). The optical coupler 162 splits the low coherence light L0 into the reference light LR and the signal light LS.

  The optical coupler 162 has both functions of a means for splitting light (splitter) and a means for superposing light (coupler), but here it is conventionally referred to as “optical coupler”. .

  The reference light LR generated by the optical coupler 162 is guided by an optical fiber 163 made of a single mode fiber or the like and emitted from the end face of the fiber. The emitted reference light LR is collimated by the collimator lens 171 and then reflected by the reference mirror 174 (reference object) via the glass block 172 and the density filter 173.

  The reference light LR reflected by the reference mirror 174 passes through the density filter 173 and the glass block 172 again, and is condensed on the fiber end surface of the optical fiber 163 by the collimator lens 171. The collected reference light LR is guided to the optical coupler 162 through the optical fiber 163.

  The glass block 172 and the density filter 173 are used as delay means for matching the optical path lengths (optical distances) of the reference light LR and the signal light LS, and as means for matching the dispersion characteristics of the reference light LR and the signal light LS. It is working.

  Further, the reference mirror 174 is configured to be moved in the traveling direction of the reference light LR (the arrow direction shown in FIG. 3). Thereby, the optical path length of the reference light LR corresponding to the axial length of the eye E to be examined is secured. The reference mirror 174 is moved by a drive mechanism including a drive device such as a motor (reference mirror drive mechanism 243 described later; see FIG. 5).

  On the other hand, the signal light LS generated by the optical coupler 162 is guided to the end of the connection line 152 by an optical fiber 164 made of a single mode fiber or the like. An optical fiber 152 a is conducted inside the connection line 152. Here, the optical fiber 164 and the optical fiber 152a may be configured by a single optical fiber, or may be formed integrally by joining the end faces thereof. Good. In any case, it is sufficient that the optical fibers 164 and 152a are configured to transmit the signal light LS between the fundus camera unit 1A and the OCT unit 150.

  The signal light LS is guided through the connection line 152 and guided to the fundus camera unit 1A. Then, the eye E is passed through the lens 142, the scanning unit 141, the dichroic mirror 134, the photographing lens 126, the relay lens 125, the variable magnification lens 124, the photographing aperture 121, the hole 112a of the aperture mirror 112, and the objective lens 113. (At this time, the barrier filters 122 and 123 are respectively retracted from the optical path).

  The signal light LS incident on the eye E is imaged and reflected on the fundus (retina) Ef. At this time, the signal light LS is not only reflected by the surface of the fundus oculi Ef, but also reaches the deep region of the fundus oculi Ef and is scattered at the refractive index boundary. Therefore, the signal light LS passing through the fundus oculi Ef is light including information reflecting the surface morphology of the fundus oculi Ef and information reflecting the state of backscattering at the refractive index boundary of the deep fundus tissue. This light may be simply referred to as “fundus reflected light of the signal light LS”.

  The fundus reflection light of the signal light LS travels in the reverse direction in the above path, is condensed on the end surface 152b of the optical fiber 152a, enters the OCT unit 150 through the optical fiber 152, and returns to the optical coupler 162 through the optical fiber 164. Come. The optical coupler 162 superimposes the signal light LS and the reference light LR reflected by the reference mirror 174 to generate interference light LC. The generated interference light LC is guided to the spectrometer 180 through an optical fiber 165 made of a single mode fiber or the like.

  Here, the “interference light generating means” of the present invention is configured by an interferometer including at least an optical coupler 162, optical fibers 163 and 164, and a reference mirror 174. In the present embodiment, a Michelson interferometer is used. However, for example, any type of interferometer such as a Mach-Zehnder type can be appropriately used.

  The spectrometer (spectrometer) 180 includes a collimator lens 181, a diffraction grating 182, an imaging lens 183, and a CCD 184. The diffraction grating 182 of the present embodiment is a transmission diffraction grating, but of course, a reflection diffraction grating can also be used. Of course, other photodetecting elements can be used instead of the CCD 184. Such a light detection element corresponds to an example of the “detection means” of the present invention.

  The interference light LC incident on the spectrometer 180 is converted into a parallel light beam by the collimator lens 181 and then split (spectral decomposition) by the diffraction grating 182. The split interference light LC is imaged on the imaging surface of the CCD 184 by the imaging lens 183. The CCD 184 receives this interference light LC and converts it into an electrical detection signal, and outputs this detection signal to the arithmetic and control unit 200.

[Configuration of arithmetic control unit]
Next, the configuration of the arithmetic and control unit 200 will be described. The arithmetic and control unit 200 analyzes a detection signal input from the CCD 184 of the spectrometer 180 of the OCT unit 150 and performs a process of forming a tomographic image of the fundus oculi Ef of the eye E to be examined. The analysis method at this time is the same as the conventional Fourier domain OCT method.

  The arithmetic and control unit 200 forms a two-dimensional image (image data) indicating the form of the surface (retina) of the fundus oculi Ef based on video signals output from the imaging devices 10 and 12 of the fundus camera unit 1A. I do.

  Furthermore, the arithmetic and control unit 200 controls each part of the fundus camera unit 1A and the OCT unit 150.

  Control of the fundus camera unit 1A includes, for example, output control of illumination light by the observation light source 101 and the imaging light source 103, control of insertion / retraction operation of the exciter filters 105 and 106 and barrier filters 122 and 123 on the optical path, LCD 140, etc. Display control, movement control of the aperture stop 110 (control of the aperture value), control of the aperture value of the photographing aperture 121, control of movement of the variable power lens 124 (control of magnification), and the like. The arithmetic and control unit 200 controls the rotation operation of the galvanometer mirrors 141A and 141B in the scanning unit 141.

  On the other hand, as control of the OCT unit 150, output control of low coherence light by the low coherence light source 160, movement control of the reference mirror 174, control of the accumulation time of the CCD 184, and the like are performed.

  An example of the hardware configuration of the arithmetic and control unit 200 that operates as described above will be described with reference to FIG. The arithmetic and control unit 200 has a hardware configuration similar to that of a conventional computer. Specifically, it includes a microprocessor 201 (CPU, MPU, etc.), RAM 202, ROM 203, hard disk drive (HDD) 204, keyboard 205, mouse 206, display 207, image forming board 208, and communication interface (I / F) 208. It consists of These units are connected via a bus 200a.

  The microprocessor 201 executes an operation characteristic of the present embodiment by expanding the control program 204 a stored in the hard disk drive 204 on the RAM 202.

  Further, the microprocessor 201 executes control of each part of the device described above, various arithmetic processes, and the like. Also, control of each part of the device corresponding to operation signals from the keyboard 205 and mouse 206, control of display processing by the display 207, control of transmission / reception processing of various data and control signals by the communication interface 209, and the like are executed.

  The keyboard 205, the mouse 206, and the display 207 are used as a user interface of the fundus oculi observation device 1. The keyboard 205 is used as a device for inputting, for example, letters and numbers. The mouse 206 is used as a device for performing various input operations on the display screen of the display 207.

  The display 207 is an arbitrary display device such as an LCD or a CRT (Cathode Ray Tube), displays an image of the fundus oculi Ef formed by the fundus oculi observation device 1, and displays various operation screens and setting screens. To do.

  Note that the user interface of the fundus oculi observation device 1 is not limited to such a configuration. For example, a function for displaying and outputting various information such as a trackball, a joystick, a touch panel LCD, a control panel for ophthalmic examination, and the like. Any user interface means having a function of inputting various information can be used.

  The image forming board 208 is a dedicated electronic circuit that performs processing for forming an image (image data) of the fundus oculi Ef of the eye E. The image forming board 208 is provided with a fundus image forming board 208a and an OCT image forming board 208b. The fundus image forming board 208a is a dedicated electronic circuit that operates to form image data of a fundus image based on video signals from the imaging device 10 and the imaging device 12 of the fundus camera unit 1A. The OCT image forming board 208b is a dedicated electronic circuit that operates to form image data of a tomographic image of the fundus oculi Ef based on a detection signal from the CCD 184 of the spectrometer 180 of the OCT unit 150. By providing such an image forming board 208, the processing speed of processing for forming image data of a fundus image or a tomographic image can be improved.

  The communication interface 209 performs a process of transmitting a control signal from the microprocessor 201 to the fundus camera unit 1A or the OCT unit 150. The communication interface 209 receives video signals from the imaging devices 10 and 12 of the fundus camera unit 1 </ b> A and detection signals from the CCD 184 of the OCT unit 150 and inputs them to the image forming board 208. At this time, the communication interface 209 operates to input video signals from the imaging devices 10 and 12 to the fundus image forming board 208a and to input detection signals from the CCD 184 to the OCT image forming board 208b.

  When the arithmetic and control unit 200 is connected to a network such as a LAN (Local Area Network) or the Internet, the communication interface 209 is equipped with a network adapter such as a LAN card and a communication device such as a modem. It is possible to configure to perform data communication via a network. In that case, a server for storing the control program 204a can be installed, and the arithmetic and control unit 200 can be configured as a client terminal of the server.

[Control system configuration]
The configuration of the control system of the fundus oculi observation device 1 having the above configuration will be described with reference to FIGS. In the block diagram shown in FIG. 5, the part related to the operation and processing according to the present invention is particularly described in the configuration of the fundus oculi observation device 1. FIG. 6 shows an example of the configuration of the operation panel 3a provided in the fundus camera unit 1A. In the block diagram shown in FIG. 7, the detailed configuration of the arithmetic and control unit 200 is described.

(Control part)
The control system of the fundus oculi observation device 1 is configured around the control unit 210 of the arithmetic and control unit 200. The control unit 210 includes a microprocessor 201, a RAM 202, a ROM 203, a hard disk drive 204 (control program 204a), a communication interface 209, and the like.

  The control unit 210 executes the above-described control process by the microprocessor 201 that operates based on the control program 204a. In particular, the control of the mirror drive mechanisms 241 and 242 of the fundus camera unit 1A for independently operating the galvanometer mirrors 141A and 141B, and the reference mirror drive mechanism 243 for moving the reference mirror 174 in the traveling direction of the reference light LR. Execute control etc.

  The control unit 210 also detects two types of images captured by the fundus oculi observation device 1, that is, a two-dimensional image (fundus image Ef ′) of the surface of the fundus oculi Ef by the fundus camera unit 1A and the detection obtained by the OCT unit 150. Control is performed to display on the display 207 of the user interface 240 a tomographic image of the fundus oculi Ef formed based on the signal. These images can be displayed separately on the display 207, or they can be displayed side by side at the same time. Details of the configuration of the control unit 210 will be described later with reference to FIG.

(Image forming part)
The image forming unit 220 performs processing for forming image data of a fundus image based on video signals from the imaging devices 10 and 12 of the fundus camera unit 1A, and a tomogram of the fundus oculi Ef based on a detection signal from the CCD 184 of the OCT unit 150. And processing for forming image data of the image. The image forming unit 220 includes an image forming board 208, a communication interface 209, and the like. In the present specification, “image” and “image data” corresponding to the “image” may be identified with each other.

  The image forming unit 220 constitutes an example of the “image forming unit” of the present invention together with the fundus camera unit 1A and the OCT unit 150. Here, each part of the fundus camera unit 1A for acquiring a two-dimensional image of the surface of the fundus oculi Ef and the image forming unit 220 correspond to an example of the “first image forming unit” in the present invention. Further, each part of the fundus camera unit 1A for acquiring a tomographic image of the fundus oculi Ef, the OCT unit 150, and the image forming unit 220 correspond to an example of the “second image forming unit” of the present invention. .

(Image processing unit)
The image processing unit 230 performs various types of image processing on the image data of the image formed by the image forming unit 220. For example, processing for forming image data of a three-dimensional image of the fundus oculi Ef based on a tomographic image of the fundus oculi Ef based on a detection signal from the OCT unit 150, various correction processes such as image brightness adjustment, and the like are executed. .

  Here, the image data of a three-dimensional image is image data obtained by assigning pixel values to a plurality of voxels arranged three-dimensionally, and is called volume data, voxel data, or the like. When displaying an image based on volume data, the image processing unit 230 performs rendering processing (volume rendering, MIP (Maximum Intensity Projection), etc.) on the volume data, and views the image from a specific gaze direction. Acts to form image data of a pseudo three-dimensional image. A pseudo three-dimensional image based on this image data is displayed on a display device such as the display 207.

(User interface)
As shown in FIG. 7, the user interface (UI) 240 includes a display unit 240A composed of a display device such as a display 207, and an operation unit 240B composed of an input device and an operation device such as a keyboard 205 and a mouse 206. .

(control panel)
The operation panel 3a of the fundus camera unit 1A will be described. For example, as shown in FIG. 13, the photographing panel 3a is disposed on the gantry 3 of the fundus camera unit 1A. Unlike the conventional configuration described in the section “Background Art”, the operation panel 3a in the present embodiment includes an operation unit used for inputting an operation request for acquiring a two-dimensional image of the surface of the fundus oculi Ef, An operation unit used for operation input for acquiring a tomographic image of the fundus oculi Ef is provided (only the former operation unit is conventionally used). As a result, OCT can be performed in the same manner as when operating a conventional fundus camera.

  As shown in FIG. 6, the operation panel 3a in this embodiment includes a menu switch 301, a split switch 302, a photographing light amount switch 303, an observation light amount switch 304, a chin rest switch 305, a photographing switch 306, a zoom switch 307, and an image switch. A switch 308, a fixation target changeover switch 309, a fixation target position adjustment switch 310, a fixation target size changeover switch 311 and a mode changeover knob 312 are provided.

  The menu switch 301 is a predetermined menu for the user to select and specify various menus (such as a shooting menu for shooting a two-dimensional image or a tomographic image of the surface of the fundus oculi Ef, a setting menu for performing various setting inputs). This switch is operated to display the menu screen. When the menu switch 301 is operated, the operation signal is input to the control unit 210. In response to the input of the operation signal, the control unit 210 displays a menu screen on the touch panel monitor 11 or the display unit 240A. Note that a control unit (not shown) may be provided in the fundus camera unit 1 </ b> A so that the control unit displays a menu screen on the touch panel monitor 11.

  The split switch 302 is a switch operated to switch on / off of a split bright line for focusing (see, for example, JP-A-9-66031, etc., also referred to as a split target, a split mark, etc.). Note that the configuration (split bright line projection unit) for projecting the split bright line onto the eye E is stored, for example, in the fundus camera unit 1A (not shown in FIG. 1). When the split switch 302 is operated, the operation signal is input to the control unit 210 (or the control unit in the fundus camera unit 1A; the same applies hereinafter). In response to the input of the operation signal, the control unit 210 controls the split bright line projection unit to project the split bright line on the eye E.

  The imaging light amount switch 303 is a switch operated to adjust the output light amount (imaging light amount) of the imaging light source 103 according to the state of the eye E (for example, the degree of turbidity of the crystalline lens). The photographing light amount switch 303 includes, for example, a photographing light amount increase switch “+” for increasing the photographing light amount, a photographing light amount decrease switch “−” for decreasing the photographing light amount, and a predetermined initial value ( And a reset switch (a central button) for setting to a default value. When one of the photographing light amount switches 303 is operated, the operation signal is input to the control unit 210. The control unit 210 controls the photographing light source 103 according to the input operation signal and adjusts the photographing light amount.

  The observation light amount switch 304 is a switch operated to adjust the output light amount (observation light amount) of the observation light source 101. The observation light amount switch 304 is provided with, for example, an observation light amount increase switch “+” for increasing the observation light amount and a photographing light amount decrease switch “−” for decreasing the observation light amount. When one of the observation light amount switches 304 is operated, the operation signal is input to the control unit 210. The controller 210 controls the observation light source 101 according to the input operation signal to adjust the observation light quantity.

  The chin rest switch 305 is a switch for moving the position of the chin rest 6 shown in FIG. The chin rest switch 305 is provided with, for example, an upward movement switch (upward triangle) for moving the chin rest 6 upward and a downward movement switch (downward triangle) for moving the chin rest 6 downward. ing. When one of the chin rest switches 305 is operated, the operation signal is input to the control unit 210. The control unit 210 controls the chin rest moving mechanism (not shown) according to the input operation signal to move the chin rest 6 upward or downward.

  The imaging switch 306 is a switch used as a trigger switch for acquiring a two-dimensional image of the surface of the fundus oculi Ef or a tomographic image of the fundus oculi Ef. When the shooting switch 306 is operated when a menu for shooting a two-dimensional image is selected, the control unit 210 that receives the operation signal controls the shooting light source 103 to output shooting illumination light, and A two-dimensional image of the surface of the fundus oculi Ef is displayed on the display 240A or the touch panel monitor 11 based on the video signal output from the imaging device 10 that has detected fundus reflection light. On the other hand, when the imaging switch 306 is operated while the menu for acquiring the tomographic image is selected, the control unit 210 that receives the operation signal controls the low coherence light source 160 to output the low coherence light L0. The fundus Ef formed by the image forming unit 220 (and the image processing unit 230) based on the detection signal output from the CCD 184 that controls the galvanometer mirrors 141A and 141B to scan the signal light LS and detects the interference light LC. Are displayed on the display 240A or the touch panel monitor 11.

  The zoom switch 307 is a switch operated to change the angle of view (zoom magnification) when photographing the fundus oculi Ef. Each time the zoom switch 307 is operated, for example, a shooting angle of view of 45 degrees and 22.5 degrees are alternately set. When the zoom switch 307 is operated, the control unit 210 that has received the operation signal controls a variable power lens driving mechanism (not shown) and moves the variable power lens 124 in the optical axis direction to change the shooting angle of view. .

  The image changeover switch 308 is a switch operated to change the display image. When the image changeover switch 308 is operated while the fundus observation image (two-dimensional image of the surface of the fundus oculi Ef based on the video signal from the imaging device 12) is displayed on the display unit 240A or the touch panel monitor 11, the operation signal is displayed. In response, the control unit 210 displays a tomographic image of the fundus oculi Ef on the display unit 240A or the touch panel monitor 11. On the other hand, when the image changeover switch 308 is operated while a tomographic image of the fundus is displayed on the display unit 240A or the touch panel monitor 11, the control unit 210 that has received the operation signal displays the fundus observation image on the display unit 240A or It is displayed on the touch panel monitor 11.

  The fixation target switching switch 309 is a switch operated to switch the display position of the internal fixation target on the LCD 140 (that is, the projection position of the internal fixation target on the fundus oculi Ef). By operating this fixation target changeover switch 309, the display position of the internal fixation target is, for example, the display position of the internal fixation target as “a fixation position for acquiring an image of a peripheral region around the fundus oculi”. , "Fixing position for acquiring an image of the peripheral region of the macula" and "Fixing position for acquiring an image of the peripheral region of the optic nerve head" can be switched cyclically . The control unit 210 displays the internal fixation target at different positions on the display surface of the LCD 140 in response to the operation signal from the fixation target switching switch 309. Note that the display positions of the internal fixation target corresponding to the above three fixation positions are set in advance based on, for example, clinical data, or set in advance for each eye E (image of the fundus oculi Ef). ing.

  The fixation target position adjustment switch 310 is a switch operated to adjust the display position of the internal fixation target. The fixation target position adjustment switch 310 includes, for example, an upward movement switch for moving the display position of the internal fixation target upward, a downward movement switch for moving downward, and a leftward movement switch. A left movement switch, a right movement switch for moving to the right, and a reset switch for moving to a predetermined initial position (default position) are provided. Upon receiving an operation signal from any of these switches, the control unit 310 controls the LCD 140 in accordance with the operation signal to move the display position of the internal fixation target.

  The fixation target size switching switch 311 is a switch operated to change the size of the internal fixation target. When the fixation target size changeover switch 311 is operated, the control unit 210 that has received the operation signal changes the display size of the internal fixation target displayed on the LCD 140. For example, the display size of the internal fixation target can be switched alternately between “normal size” and “enlarged size”. Thereby, the size of the projected image of the fixation target projected onto the fundus oculi Ef is changed. When receiving an operation signal from the fixation target size changeover switch 311, the control unit 210 controls the LCD 140 according to the operation signal to change the display size of the internal fixation target.

  The mode switching knob 312 scans various imaging modes (fundus imaging mode for capturing a two-dimensional image of the fundus oculi Ef, B-scan mode for performing a B-scan of the signal light LS, and the signal light LS three-dimensionally. The knob is rotated to select a three-dimensional scan mode for the purpose. Further, the mode switching knob 312 may be configured to select a reproduction mode for reproducing and displaying the acquired two-dimensional image or tomographic image of the fundus oculi Ef. In addition, it may be possible to select an imaging mode for controlling to perform fundus imaging immediately after scanning with the signal light LS. Control for performing each of these modes is executed by the control unit 210.

  Hereinafter, a control mode of scanning of the signal light LS by the control unit 210 will be described, and a mode of processing of the detection signal from the OCT unit 150 by the image forming unit 220 and the image processing unit 230 will be described. Note that the processing of the image forming unit 220 and the like for the video signal from the fundus camera unit 1A is executed in the same manner as in the prior art, and thus description thereof is omitted.

[Scanning signal light]
As described above, the scanning of the signal light LS is performed by changing the direction of the reflecting surfaces of the galvanometer mirrors 141A and 141B of the scanning unit 141 of the fundus camera unit 1A. The control unit 210 controls the mirror driving mechanisms 241 and 242 to change the directions of the reflecting surfaces of the galvanometer mirrors 141A and 141B, respectively, and scans the signal light LS on the fundus oculi Ef.

  When the direction of the reflecting surface of the galvanometer mirror 141A is changed, the signal light LS is scanned in the horizontal direction (x direction in FIG. 1) on the fundus oculi Ef. On the other hand, when the direction of the reflecting surface of the galvanometer mirror 141A is changed, the signal light LS is scanned in the vertical direction (y direction in FIG. 1) on the fundus oculi Ef. Further, the signal light LS can be scanned in a direction in which the x direction and the y direction are combined by simultaneously changing the directions of the reflecting surfaces of both the galvanometer mirrors 141A and 141B. That is, by controlling these two galvanometer mirrors 141A and 141B, the signal light LS can be scanned in an arbitrary direction on the xy plane.

  FIG. 8 illustrates an example of a scanning mode of the signal light LS for forming an image of the fundus oculi Ef. FIG. 8A illustrates an example of a scanning mode of the signal light LS when the fundus oculi Ef is viewed from the direction in which the signal light LS is incident on the eye E (that is, viewed from the −z direction to the + z direction in FIG. 1). Represents. FIG. 8B shows an example of an arrangement form of scanning points (positions where image measurement is performed) on each scanning line on the fundus oculi Ef.

  As shown in FIG. 8A, the signal light LS is scanned in a rectangular scanning region R set in advance. In this scanning region R, a plurality (m) of scanning lines R1 to Rm are set in the x direction. When the signal light LS is scanned along each scanning line Ri (i = 1 to m), a detection signal of the interference light LC is generated.

  Here, the direction of each scanning line Ri is referred to as a “main scanning direction”, and a direction orthogonal to the direction is referred to as a “sub-scanning direction”. Therefore, scanning in the main scanning direction of the signal light LS is executed by changing the direction of the reflecting surface of the galvano mirror 141A, and scanning in the sub-scanning direction changes the direction of the reflecting surface of the galvano mirror 141B. Executed by.

  On each scanning line Ri, as shown in FIG. 8B, a plurality (n) of scanning points Ri1 to Rin are set in advance.

  In order to execute the scanning shown in FIG. 8, the control unit 210 first controls the galvanometer mirrors 141A and 141B to set the incidence target of the signal light LS on the fundus oculi Ef to the scanning start position RS ( Set to scan point R11). Subsequently, the control unit 210 controls the low coherence light source 2, causes the low coherence light L0 to flash, and causes the signal light LS to enter the scanning start position RS. The CCD 184 receives the interference light LC based on the fundus reflection light at the scanning start position RS of the signal light LS and outputs a detection signal to the control unit 210.

  Next, the control unit 210 controls the galvanometer mirror 141A, scans the signal light LS in the main scanning direction, sets the incident target at the scanning point R12, flashes the low coherence light L0, and scans the scanning point. The signal light LS is incident on R12. The CCD 184 receives the interference light LC based on the fundus reflection light at the scanning point R12 of the signal light LS, and outputs a detection signal to the control unit 210.

  Similarly, the controller 210 sequentially flashes the low coherence light L0 at each scanning point while sequentially moving the incident target of the signal light LS from the scanning points R13, R14,..., R1 (n−1), R1n. By emitting light, a detection signal output from the CCD 184 corresponding to the interference light LC for each scanning point is acquired.

  When the measurement at the last scanning point R1n of the first scanning line R1 is completed, the control unit 210 controls the galvanometer mirrors 141A and 141B at the same time so that the incident target of the signal light LS is changed along the line changing scan r. The second scanning line R2 is moved to the first scanning point R21. And the detection signal corresponding to each scanning point R2j is each acquired by performing the above-mentioned measurement about each scanning point R2j (j = 1-n) of this 2nd scanning line R2.

  Similarly, measurement is performed for each of the third scanning line R3,..., The m−1th scanning line R (m−1), and the mth scanning line Rm, and a detection signal corresponding to each scanning point. To get. Note that the symbol RE on the scanning line Rm is a scanning end position corresponding to the scanning point Rmn.

  Thereby, the control unit 210 acquires m × n detection signals corresponding to m × n scanning points Rij (i = 1 to m, j = 1 to n) in the scanning region R. Hereinafter, the detection signal corresponding to the scanning point Rij may be represented as Dij.

  The linked control of the scanning point movement and the output of the low-coherence light L0 as described above is performed, for example, by transmitting a control signal to the mirror driving mechanisms 241 and 242 and a control signal (output request signal) for the low-coherence light source 2. This can be realized by synchronizing the transmission timing with each other.

  When the galvanometer mirrors 141A and 141B are operated as described above, the control unit 210 stores the position of each scanning line Ri and the position of each scanning point Rij (coordinates in the xy coordinate system) as information indicating the operation content. It has come to keep. This stored content (scanning position information) is used in the image forming process as in the prior art.

[About image processing]
Next, an example of processing related to an OCT image by the image forming unit 220 and the image processing unit 230 will be described.

  The image forming unit 220 executes a process of forming a tomographic image of the fundus oculi Ef along each scanning line Ri (main scanning direction). Further, the image processing unit 230 executes a process for forming a three-dimensional image of the fundus oculi Ef based on the tomographic image formed by the image forming unit 220.

  The tomographic image forming process by the image forming unit 220 is configured to include a two-stage arithmetic process, as in the prior art. In the first stage of arithmetic processing, an image in the depth direction (z direction shown in FIG. 1) of the fundus oculi Ef at the scanning point Rij is formed based on the detection signal Dij corresponding to each scanning point Rij.

  FIG. 9 shows an aspect of a tomographic image (group) formed by the image forming unit 220. In the second stage arithmetic processing, a tomographic image Gi of the fundus oculi Ef along this scanning line Ri is formed for each scanning line Ri based on the image in the depth direction at the n scanning points Ri1 to Rin above it. . At this time, the image forming unit 220 determines the arrangement and interval of the scanning points Ri1 to Rin with reference to the positional information (scanning position information described above) of the scanning points Ri1 to Rin, and forms the scanning line Ri. It is supposed to be. Through the above processing, m tomographic images (tomographic image groups) G1 to Gm at different positions in the sub-scanning direction (y direction) are obtained. The respective image data of these tomographic images G1 to Gm correspond to the image data Ga of the tomographic image shown in FIG. 7 (described later).

  Next, a process for forming a three-dimensional image of the fundus oculi Ef by the image processing unit 230 will be described. A three-dimensional image of the fundus oculi Ef is formed based on the m number of tomographic images obtained by the above arithmetic processing. The image processing unit 230 forms a three-dimensional image of the fundus oculi Ef by performing a known interpolation process for interpolating an image between adjacent tomographic images Gi and G (i + 1).

  At this time, the image processing unit 230 determines the arrangement and interval of each scanning line Ri with reference to the position information of each scanning line Ri, and forms this three-dimensional image. In this three-dimensional image, a three-dimensional coordinate system (x, y, z) is set based on the position information (the above-described scanning position information) of each scanning point Rij and the z coordinate in the image in the depth direction. .

  Further, the image processing unit 230 can form a tomographic image of the fundus oculi Ef in a cross section in an arbitrary direction other than the main scanning direction (x direction) based on the three-dimensional image. When a cross section is designated, the image processing unit 230 identifies the position of each scanning point (and / or the interpolated depth direction image) on the designated cross section, and the depth direction image (and / or at each specific position). (Or an interpolated image in the depth direction) is extracted from the three-dimensional image, and a plurality of extracted images in the depth direction are arranged to form a tomographic image of the fundus oculi Ef in the designated cross section.

  Note that an image Gmj shown in FIG. 9 represents an image in the depth direction (z direction) at the scanning point Rmj on the scanning line Rm. Similarly, an image in the depth direction at each scanning point Rij on each scanning line Ri, which is formed in the above-described first stage arithmetic processing, is represented as “image Gij”.

[Detailed configuration of arithmetic control unit]
A detailed configuration of the arithmetic and control unit 200 will be described with reference to FIG. Here, configurations of the control unit 210 and the image processing unit 230 of the arithmetic and control unit 200 will be described.

  The control unit 210 includes a main control unit 211, an image storage unit 212, an information storage unit 213, and a position information generation unit 214.

  The image processing unit 230 includes a scanning region displacement calculation unit 231, a fixation position displacement calculation unit 232, a depth position displacement calculation unit 233, an integrated image generation unit 234, an integrated image displacement calculation unit 235, and an image position change unit 236. Is provided. The image processing unit 230 corresponds to an example of the “image processing unit” of the present invention.

(Main control unit)
The main control unit 211 includes a microprocessor 201 and the like, and controls each part of the fundus oculi observation device 1 (described above).

(Image storage unit)
The image storage unit 212 includes image data (for example, image data indicated by reference numerals 212a and 212b) of a two-dimensional image (fundus image) of the surface of the fundus oculi Ef formed by the image forming unit 220, and image data (for example, reference numerals of tomographic images). Image data indicated by Ga and Gb). Processing for storing image data in the image storage unit 212 and processing for reading image data from the image storage unit 212 are executed by the main control unit 211. The image storage unit 212 includes a storage device such as the hard disk drive 204.

  It is assumed that the fundus image data 212a and the tomographic image data Ga are acquired almost simultaneously. In addition, it is assumed that the fundus image data 212b and the tomographic image data Gb are acquired almost simultaneously. Here, “obtained almost simultaneously (substantially simultaneously)” means, for example, a case where both image data are acquired simultaneously, a case where the other is acquired immediately after acquisition of one image data, or a series of When both image data are acquired in the inspection process, it means that both image data are acquired with almost no time difference. On the contrary, the image data 212a and the image data 212b and the like are obtained by acquiring the other through a considerable time interval after acquisition of one of the image data, for example, the examination date and time when they were acquired is different. The

(Information storage unit)
The information storage unit 213 stores position information (for example, information indicated by reference numerals 213a and 213b). This position information is information indicating the position of the tomographic image in the fundus image with respect to the two-dimensional image (fundus image) and tomographic image of the surface of the fundus oculi Ef acquired almost simultaneously. The position information is generated by the position information generation unit 214 (the generation method will be described later).

  This position information will be described in more detail. A two-dimensional XY coordinate system is defined in advance on the imaging surface of the imaging device 10a of the imaging device 10 (not shown). Two-dimensional coordinates based on the XY coordinate system are set in the fundus image captured by the imaging apparatus 10. This XY coordinate system defines a plane parallel to the plane formed by the x and y coordinates of the xyz coordinate system shown in FIG. Here, the coordinate scale (the length of the unit distance) of the two coordinate systems may be the same or different. The directions of the coordinate axes of the two coordinate systems may or may not match.

  In general, when the scale and direction of the coordinate axes of two coordinate systems are different, the direction of the coordinate axis can be matched by translation and rotation, and the scale is matched by enlarging / reducing the length of the unit distance of the coordinate axis (Ie, a unique coordinate transformation can be performed).

  Further, as shown in FIG. 1, a z coordinate (Z coordinate; not shown) having a positive direction in the depth direction of the fundus oculi Ef is defined in a direction orthogonal to the xy plane (XY plane). The z coordinate and the Z coordinate may be the same or different from each other. Hereinafter, it is assumed that the directions of the corresponding coordinate axes of the XYZ coordinate system and the xyz coordinate system are the same, and the scales of the coordinate axes are also equal.

  Each position information stored in the information storage unit 213 includes, for example, at least one of scanning area information, fixation position information, and depth information. Note that the position information according to the present invention does not necessarily include one of these pieces of information, and may include arbitrary information indicating the position of the tomographic image in the fundus image.

  The scanning area information is information that expresses, in the xy coordinate system, an area (scanning area) scanned with the signal light LS when acquiring a tomographic image. An example of the scanning region of the signal light LS is shown in FIG. In the scanning mode shown in the figure, as described above, the signal light LS is scanned in the main scanning direction (direction parallel to the x-axis) and the sub-scanning direction (direction parallel to the y-axis), and the rectangular scanning region R Is forming. The scanning area information corresponding to the scanning area R can be expressed by a range in the main scanning direction and a range in the sub-scanning direction, for example (x1 ≦ x ≦ x2, y1 ≦ y ≦ y2).

  Note that the shape of the scanning region of the signal light LS is not limited to a rectangular shape. For example, when the signal light LS is scanned concentrically or spirally, a circular scanning region is formed. The scanning area information in this case can be expressed by, for example, the coordinates (x0, y0) of the center of the circular scanning area and the radius r.

  The fixation position information is information that expresses the projection position of the internal fixation target on the fundus oculi Ef at the time of obtaining the tomographic image in the xy coordinate system. This fixation position information can be expressed by, for example, coordinate values (xf, yf) of the center position of the internal fixation target projected onto the fundus oculi Ef.

  Note that the fixation position information is not limited to information in which the actual projection position of the internal fixation target projected onto the fundus oculi Ef is directly expressed in the xy coordinate system. For example, the information obtained by converting the display position of the internal fixation target on the LCD 140 (the coordinate value expressed in the two-dimensional coordinate system defined on the display surface of the LCD 140) into the coordinate value of the xy coordinate system is used as the fixation position. It can be used as information. Here, since the internal fixation target is displayed on the LCD 140 and projected onto the fundus oculi Ef via the photographing optical system 120, the projection position on the fundus oculi Ef is the display position on the LCD 140, the optical data of the photographing optical system 120, The calculation can be performed based on the alignment position in the z direction of the fundus oculi Ef.

  The depth information is information indicating the position (z coordinate value) in the depth direction of the tomographic image of the fundus oculi Ef. In other words, the position of the fundus image in the depth direction with respect to the surface of the fundus oculi Ef (which is the imaging target of the fundus image). It is information which shows.

  The fundus oculi Ef has a retina, a choroid, and a sclera. As the depth information, a position in the z direction in a tomographic image of an image corresponding to a specific layer included in any of these films can be used. For example, the position in the z direction in the tomographic image of the image corresponding to the retinal pigment epithelium layer of the retina (or the boundary between the retinal pigment epithelium and the choroid) can be employed as the depth information. Here, the retinal pigment epithelium layer is a layer that reflects the signal light LS well, and is relatively clearly depicted in the tomographic image, and therefore can be suitably used as a reference for depth information.

  In the tomographic image including the optic disc, for example, the position in the z direction (z coordinate value) in the tomographic image of the image corresponding to the bottom of the optic disc dent can be used as the depth information.

(Location information generator)
The position information generation unit 214 performs the process of generating the above-described position information, and corresponds to an example of “position information generation unit” of the present invention. Hereinafter, a process for generating scanning area information, a process for generating fixation position information, and a process for generating depth information will be described.

  First, processing for generating scanning area information will be described. The scanning region of the signal light LS is specified by operating the operation unit 240B by the user before acquiring a tomographic image of the fundus oculi Ef. This operation is executed by displaying an observation image of the fundus oculi Ef on the display unit 240A and performing a drag-and-drop operation with a mouse so as to surround a desired region on the observation image. For example, a rectangular scanning region having a diagonal line connecting the position where the mouse drag operation is started and the position where the drop operation is performed is set.

  The position information generation unit 214 generates scanning region information when the fundus image (captured image) of the fundus oculi Ef and the tomographic image are acquired almost simultaneously based on the scanning region specified on the observation image of the fundus oculi Ef. . At this time, it is assumed that the fixation position of the eye E when the observation image is displayed is the same as the fixation position when the fundus image and the tomographic image are acquired.

  A specific example of scanning area information generation processing when the scanning area is designated by a mouse drag and drop operation will be described. When the scanning area is designated, the x coordinate value and y coordinate value of the drag start position and the x coordinate value and y coordinate value of the drop position are input from the user interface 240 to the control unit 210, and the position information generation unit 214. Sent to. Assuming that the coordinates of the drag start position are (x1, y1) and the coordinates of the drop position are (x2, y2), the position information generation unit 214 has an area (x1 ≦ x ≦ x2, y1 ≦ y ≦ y2) on the fundus image. ) Is generated.

  Next, processing for generating fixation position information will be described. As for the fixation position of the eye E, before the tomographic image of the fundus oculi Ef is acquired, the user operates the fixation target changeover switch 309, the fixation target position adjustment switch 310, or the fixation target size changeover switch 311 of the operation panel 3a. It is specified by doing.

  When the fixation position of the eye E is designated by the internal fixation target, the position information generation unit 214 obtains, for example, the coordinate value (xf, yf) of the center position of the internal fixation target projected on the fundus oculi Ef. It is set as fixation position information. At this time, it is possible to obtain a target coordinate value by analyzing an observation image (before photographing) or a fundus image (after photographing) on which the internal fixation target is projected, or the internal fixation target displayed on the LCD 140 can be obtained. A target coordinate value may be calculated based on the display position of the fixation target.

  Next, processing for generating depth information will be described. When a tomographic image of the fundus oculi Ef is acquired, image data of the tomographic image is input to the position information generation unit 214. The position information generation unit 214 analyzes the image data, extracts, for example, a portion corresponding to the retinal pigment epithelium layer, and calculates the z coordinate value of the extracted portion in the tomographic image to obtain target depth information.

  Here, instead of analyzing the image data, data used for forming the tomographic image, for example, data representing the detected intensity distribution of the interference light LC at each depth position is analyzed, and z at the depth position where the detected intensity reaches a peak is analyzed. It is also possible to obtain coordinate information to obtain depth information.

  The position information generated as described above is stored in the information storage unit 213 in association with the image data of the corresponding fundus image and the image data of the tomographic image.

(Scanning area displacement calculator)
The scanning area displacement calculation unit 231 calculates the displacement (in the xy direction) of these two coordinates based on the coordinates of the scanning area of the signal light LS indicated in each of the two scanning area information. The coordinates shown in the scanning area information corresponding to the scanning area R when acquiring the first tomographic image are (x1 ≦ x ≦ x2, y1 ≦ y ≦ y2), and the scanning area when acquiring the second tomographic image If the coordinates shown in the scanning area information corresponding to R ′ (not shown) are (x1 ′ ≦ x ≦ x2 ′, y1 ′ ≦ y ≦ y2 ′), the scanning area displacement calculation unit 231 may, for example, Displacement Δx (min) = x1−x1 ′ and Δx (max) = x2−x2 ′ and y direction displacement Δy (min) = y1−y1 ′ and Δy (max) = y2−y2 ′ are calculated, respectively. .

  Here, when the x-direction lengths of the scanning regions R and R ′ are equal (that is, when x2−x1 = x2′−x1 ′), the displacement in the x direction is Δx = x1−x1 ′ (or x2). It is sufficient to calculate -x2 '). Similarly, when the lengths in the y direction of the scanning regions R and R ′ are equal (that is, y2−y1 = y2′−y1 ′), Δy = y1−y1 ′ (or y2) as the displacement in the y direction. It is sufficient to calculate -y2 '). The scanning area displacement calculation unit 231 corresponds to an example of the “displacement calculation unit” of the present invention.

(Fixed position displacement calculation unit)
The fixation position displacement calculation unit 232 calculates the displacement (in the xy direction) of these two coordinates based on the coordinates of the projection position of the internal fixation target on the fundus oculi Ef shown in each of the two fixation position information. . The coordinates of the projection position of the internal fixation target shown in the fixation position information corresponding to the first tomographic image are (xf, yf), and the coordinates of the projection position of the internal fixation target corresponding to the second tomographic image are ( xf ′, yf ′), the fixation position displacement calculation unit 232 calculates a displacement Δxf = xf−xf ′ in the x direction and a displacement Δyf = yf−yf ′ in the y direction of these two coordinates, respectively. . The fixation position displacement calculation unit 232 corresponds to an example of the “displacement calculation unit” of the present invention.

(Depth position displacement calculation unit)
The depth position displacement calculation unit 233 calculates the displacement (in the depth direction, that is, the z direction) of the two coordinates based on the coordinates of the depth position indicated in each of the two depth information. When the coordinate shown in the depth information corresponding to the first tomographic image is z and the coordinate shown in the depth information corresponding to the second tomographic image is z ′, the depth position displacement calculation unit 233 changes the displacement of these two coordinates. Δz = z−z ′ is calculated. this

(Integrated image generator)
The integrated image generation unit 234 generates a one-dimensional image (integrated image) by integrating the tomographic images formed by the image forming unit 220 in the depth direction. That is, the image Gij in each depth direction constituting the tomographic image is integrated in the depth direction (z direction) to form a dot image. Each dot-like image indicates the accumulated luminance in the depth direction at the position of the image Gij in the depth direction that is the basis thereof. Here, “accumulate in the depth direction” means a calculation process of adding (projecting) the luminance values at the respective depth positions of the image in the depth direction in the depth direction.

  By executing such processing for each tomographic image obtained by a series of scans of the signal light LS, an image representing the form of the surface of the fundus oculi Ef in this scanning region is obtained in the same manner as the fundus image (two-dimensional image of the surface). Is obtained. The accumulated image is described in detail in Japanese Patent Application No. 2005-337628 by the present inventors. This integrated image generation unit 234 corresponds to an example of “integrated image generation means” of the present invention.

(Integrated image displacement calculator)
The integrated image displacement calculator 235 calculates the displacement in the xy direction of these integrated images based on the two integrated images based on the first and second tomographic images (group). The integrated image is formed in the same xy coordinate range as the scanning region of the signal light LS when acquiring the tomographic image that is the basis thereof. The integrated image displacement calculation unit 235 performs two integrated images in the same manner as the scanning region displacement calculation unit 231 based on the coordinates of the scanning region corresponding to each integrated image (for example, obtained by referring to the scanning region information). The displacement of is calculated.

  As another configuration example of the process of calculating the displacement of the two integrated images, the displacement can be calculated so that the correlation between the two integrated images is the highest. It is also possible to extract the feature points from the two integrated images and calculate the displacements of the feature points to obtain the displacements of the two integrated images. The integrated image displacement calculation unit 235 corresponds to an example of “integrated image displacement calculation means” of the present invention.

(Image position change part)
The image position changing unit 236 generates a tomographic image (group) based on displacement information input from the scanning region displacement calculating unit 231, the fixation position displacement calculating unit 232, the depth position displacement calculating unit 233, or the integrated image displacement calculating unit 235. ), The two tomographic images (groups) are aligned. The image position changing unit 236 corresponds to an example of the “image position changing unit” of the present invention.

  Hereinafter, the image alignment processing based on the displacement input from the scanning region displacement calculation unit 231, the image alignment processing based on the displacement input from the fixation position displacement calculation unit 232, and the depth position displacement calculation unit 233. An image alignment process based on displacement and an image alignment process based on displacement input from the integrated image displacement calculation unit 235 will be described. Further, detailed positioning processing of the tomographic image (group) by the image position displacement changing unit 236 will be described.

  First, an image alignment process based on the displacement input from the scanning region displacement calculation unit 231 will be described. The image position changing unit 236 includes the displacement Δx = x1−x1 ′ (or x2−x2 ′) in the x direction and the displacement Δy = y1 in the y direction of the two tomographic images (groups) input from the scanning region displacement calculation unit 231. Based on -y1 '(or y2-y2'), by moving at least one of the two tomographic images (group) in the x direction and the y direction, Align the position. For example, by moving the second tomographic image by Δx in the x direction and by moving Δy in the y direction, a process for adjusting the position of the second tomographic image to the position of the first tomographic image is executed.

  When the lengths in the x direction of the scanning regions R and R ′ are not equal (that is, when x2−x1 ≠ x2′−x1 ′), the displacement Δx (min) in the x direction = x1−x1 ′. And Δx (max) = x2−x2 ′), for example, at least one of the two tomographic images (group) is set so that the midpoints in the x direction of both scanning regions R and R ′ are matched. It can be configured to move. Similarly, when the lengths in the y direction of the scanning regions R and R ′ are not equal (that is, y2−y1 ≠ y2′−y1 ′), the displacement Δy (min) in the y direction = y1−y1. ′ And Δy (may) = y2−y2 ′), for example, at least one of the two tomographic images (groups) so as to match the midpoints in the y direction of both scanning regions R and R ′. Can be configured to move.

  Next, image alignment processing based on displacement input from the fixation position displacement calculation unit 232 will be described. The image position changing unit 236 has a displacement Δxf = xf−xf in the x direction of the projection position of the internal fixation target onto the fundus oculi Ef when the two tomographic images (groups) input from the fixation position displacement calculation unit 232 are acquired. ′ And the displacement in the y direction Δyf = yf−yf ′, by moving at least one of the two tomographic images (group) in the x direction and the y direction, Align each direction. For example, the second tomographic image is moved by Δxf in the x direction and is moved by Δyf in the y direction, thereby executing a process for adjusting the position of the second tomographic image to the position of the first tomographic image.

  Next, an image alignment process based on the displacement input from the depth position displacement calculation unit 233 will be described. Based on the displacement Δz = z−z ′ of the coordinates of the depth positions of the two tomographic images input from the depth position displacement calculating unit 233, the image position changing unit 236 performs the depth direction ( Align in the z direction). For example, the process of matching the position of the second tomographic image with the position of the first tomographic image is performed by moving the second tomographic image by Δz in the z direction.

  Next, image alignment processing based on displacement input from the integrated image displacement calculation unit 235 will be described. The image position changing unit 236 displaces the two accumulated images in the xy direction based on the two tomographic images (groups) input from the accumulated image displacement calculating unit 235 (represented by Δx and Δy similarly to the displacement of the scanning region). Based on the above, by moving at least one of the two tomographic images (group) in the x direction and the y direction, the respective tomographic images are aligned in the x direction and the y direction, respectively. For example, by moving the second tomographic image by Δx in the x direction and by moving Δy in the y direction, a process for adjusting the position of the second tomographic image to the position of the first tomographic image is executed. When the areas of the integrated images are different from each other, alignment is performed by matching the midpoints in the x direction and the y direction, as in the case based on the displacement of the scanning area.

  Finally, a detailed alignment process of the tomographic image (group) will be described. The image position changing unit 236 calculates a displacement for two fundus images (a two-dimensional image of the surface of the fundus oculi Ef) so that the correlation is the highest, and aligns the two fundus images based on the displacement. Also, feature points are extracted from the two fundus images, the displacements of these feature points are calculated, and the two fundus images are aligned based on the displacements. Further, using the result of the alignment of the two fundus images, the two tomographic images acquired almost simultaneously with the two fundus images are aligned in the x direction and the y direction.

  The alignment of the tomographic image based on the alignment of the fundus image is performed by, for example, the scanning region displacement calculation unit 231 (or the fixation position displacement calculation unit 232, the degree position displacement calculation unit 233, or the integrated image displacement calculation unit 235). By executing after the (rough) alignment based on the displacement information input from, it is possible to perform the alignment of the two tomographic images (group) in more detail.

[Operation]
The operation of the fundus oculi observation device 1 having the above configuration will be described with reference to FIGS. These drawings show an example of the operation of the fundus oculi observation device 1 when comparing images acquired at different examination dates and times in the follow-up of eye diseases. The operation shown in this flowchart corresponds to the case where image alignment is performed using position information. A case where image alignment is performed using the accumulated image will be described later.

[Image registration processing using location information]
First, an image alignment process using position information will be described with reference to FIGS. 10 and 11. First, a fundus image and a tomographic image (a tomographic image group; the same applies hereinafter) of the fundus oculi Ef are acquired at the first examination date and time (S1). The acquired fundus image image data 212a and tomographic image data Ga are respectively stored in the image storage unit 212 (S2). If the fundus oculi observation device 1 is connected to a network such as a LAN, the image data 212a and Ga may be stored in a database on this network.

  The position information generation unit 214 obtains the position information 213a based on information set before the image acquisition (designation information on the scanning region R of the signal light LS, designation information on the fixation position, etc.) and the acquired image information. Generate (S3). The generated position information 213a is stored in the information storage unit 213 (S4).

  Here, as the position information for image alignment in the xy direction, it is sufficient that either one of the scanning region information and the fixation position information is generated. However, here, both pieces of information are generated. To do. It is also assumed that depth information that is position information for image alignment in the z direction is also generated.

  A fundus image of the fundus oculi Ef and a tomographic image (a tomographic image group; the same applies hereinafter) at a second examination date and time when a predetermined period (for example, several days, weeks, months, years, etc.) has passed since the first examination date and time. Is acquired (S5). The acquired image data 212b of the fundus image and the image data Gb of the tomographic image are respectively stored in the image storage unit 212 (S6).

  The position information generation unit 214 generates position information 213b including scanning area information, fixation position information, and depth information, similar to the first examination date and time (S7). The generated position information 213b is stored in the information storage unit 213 (S8).

  When a predetermined operation for starting comparison of images of the fundus oculi Ef is performed, the main control unit 211 reads out image data 212b (or image data 212a) of the fundus image from the image storage unit 212, and stores the image data 212b in the image data 212b. The based fundus image Ef ′ is displayed on the display unit 240A (S9).

  Further, the main control unit 211 reads the respective scanning area information and fixation position information of the position information 213a and 213b from the information storage unit 213, an image showing two scanning areas based on the two scanning area information, An image indicating the projection position of the internal fixation target based on the two fixation position information is superimposed and displayed on the fundus oculi image Ef ′ (S10).

  Further, the main control unit 211 reads the image data Gb (or image data Ga) of the tomographic image from the image storage unit 212, and causes the display unit 240A to display the tomographic image Gb based on this image data (S11). The tomographic image Gb (Ga) is displayed on the display unit 240A in parallel with the fundus oculi image 212b (212a) and the like.

  FIG. 11 illustrates an example of a screen displayed on the display unit 240A by steps S9, S10, and S11. On the display screen of the display unit 240A, a fundus image display unit 240a on which a two-dimensional image (fundus image 212b) of the surface of the fundus oculi Ef is displayed and a tomographic image Gb of the fundus oculi Ef are displayed as shown in FIG. And a tomographic image display unit 240b.

  By step S9, the fundus image Ef ′ is displayed on the fundus image display unit 240a. Further, in step S10, a scanning region (an image indicating R) when a tomographic image is acquired at the first examination date and time, and a scanning region (an image indicating R) when a tomographic image is acquired at the second inspection date and time. 'Is displayed superimposed on the fundus oculi image Ef'. Furthermore, by step S10, the projection position (indicating image) F of the internal fixation target at the first examination date and time, and the projection position (image showing) of the internal fixation target at the second examination date and time, It is displayed superimposed on the fundus image Ef ′.

  The scanning areas R and R ′ and the projection positions F and F ′ are displayed based on the coordinates indicated in the corresponding scanning area information or fixation position information, respectively. Here, the scanning region R ′ and the projection position F ′ are generated at the time of image acquisition at the same second examination date and time as the displayed fundus image Ef ′. 2 shows the position of the tomographic image Gb at the inspection date and time 2 (that is, the position of the scanning region and the projection position of the internal fixation target) as they are.

  On the other hand, the scanning region R and the projection position F are generated at the time of image acquisition at the first examination date and time, unlike the displayed fundus image Ef ′. Accordingly, in the examinations on the first and second examination dates and times, the deviation of the image area designated as the scanning area and the deviation of the projection position of the internal fixation target (that is, the deviation of the area of the fundus oculi Ef where the fundus image was taken). In addition, there is a risk that various conditions may be deviated during the examination, such as misalignment of the apparatus with respect to the eye E. Even if these conditions are met, there is a possibility that the region of the fundus oculi Ef captured as a fundus image may be shifted when the eye E is not firmly fixed by the internal fixation target. .

  Accordingly, as shown in FIG. 11, the scanning regions R and R ′ are generally displayed at different positions, and the projection positions F and F ′ are generally displayed at different positions.

  When a plurality of tomographic images (that is, tomographic image groups) are acquired at the first and second examination dates and times, the main control unit 211 selects one of the tomographic image groups Gb (Ga) as a tomographic image display unit. 240b is displayed. As the tomographic image to be displayed, for example, an arbitrary tomographic image such as a tomographic image of a cross section including the scanning start position RS or a tomographic image of a cross section located in the middle in the sub-scanning direction (y direction) is selected.

  The main control unit 211 reads the position information 213a and 213b from the information storage unit 213 and sends the position information 213a and 213b to the image processing unit 230, and the image data 212a and 212b of the fundus image and the image data Ga and Gb of the tomographic image from the image storage unit 212. Read out and send to image processing unit 230.

  Based on the coordinates of the scanning area of the signal light LS indicated in the respective scanning area information of the position information 213a and 213b, the scanning area displacement calculation unit 231 calculates the displacement (in the xy direction) of these two coordinates (S12). .

  Further, the fixation position displacement calculation unit 232 determines the (x and y directions) of the two coordinates based on the coordinates of the projection position of the internal fixation target on the fundus oculi Ef indicated by the fixation position information of the position information 213a and 213b. The displacement is calculated (S13).

  Further, the depth position displacement calculation unit 233 calculates the displacement (in the z direction) of these two coordinates based on the depth position coordinates indicated in the depth information of the position information 213a and 213b (S14). The displacements calculated in steps S12 to S14 are input to the image position changing unit 236.

  The image position changing unit 236 converts the tomographic image Ga at the first examination date and / or the tomographic image Gb at the second examination date into the x direction and y based on the displacement of the coordinates of the scanning area calculated in step S12. Then, the two tomographic images are aligned in the xy direction (S15).

  Further, the image position changing unit 236 calculates the tomographic image Ga at the first examination date and / or the tomogram at the second examination date based on the displacement of the coordinates of the projection position of the internal fixation target calculated in step S13. The image Gb is moved in the x direction and the y direction, and the alignment of these two tomographic images in the xy direction is executed (S16).

  In addition, the image position changing unit 236 generates the tomographic image Ga at the first examination date and / or the tomographic image Gb at the second examination date and time z based on the displacement of the depth position of the tomographic image calculated in step S14. The two tomographic images are aligned in the z direction (depth direction) by moving in the direction (S17).

  Further, the image position changing unit 236 calculates a displacement based on the image data 212a and 212b of the fundus image so that the correlation between the two fundus images is the highest, and based on the displacement, aligns the two fundus images. Using the alignment result, alignment of the tomographic images Ga and Gb in the xy direction is performed (S18). This completes the tomographic image alignment process using the position information.

  Based on the result of this alignment, the main control unit 211 changes the display positions of the images R and R ′ of the scanning area and the images F and F ′ of the projection positions of the internal fixation target in the fundus image display unit 240a. Can do. By changing the display position, the images R and R ′ in the scanning area are displayed at almost the same position, and the images F and F ′ at the projection position are displayed at almost the same position. This means that the tomographic image (group) Ga at the first examination date and time is aligned with the tomographic image (group) at the second examination date and time.

[Image registration processing using accumulated images]
Next, with reference to FIG. 12, an image alignment process using the accumulated image will be described. First, similarly to the alignment process using position information, a fundus image and a tomographic image (a tomographic image group; the same applies hereinafter) of the fundus oculi Ef are acquired at the first examination date and time (S21), and image data of the fundus image is obtained. 212a and tomographic image data Ga are stored in the image storage unit 212 (S22).

  Also, a fundus image and a tomographic image (a tomographic image group; the same applies hereinafter) of the fundus oculi Ef are acquired at a second examination date and time after a predetermined period has elapsed from the first examination date and time (S23), and image data of the fundus image is obtained. 212b and tomographic image data Gb are stored in the image storage unit 212 (S24).

  Note that information indicating the scanning area of the signal light LS when the tomographic image is acquired (the above-described scanning area information) is generated and stored in the information storage unit 213 at each of the first and second examination dates and times. .

  In response to a predetermined operation, the main control unit 211 reads out image data 212b (or image data 212a) of the fundus image from the image storage unit 212, and causes the display unit 240A to display a fundus image Ef ′ based on the image data 212b. At the same time (S25), the scanning area information is read from the information storage unit 213, and an image showing the scanning areas of the first and second examination dates is superimposed and displayed on the fundus image Ef '(S26). Further, the main control unit 211 reads the image data Gb (or image data Ga) of the tomographic image from the image storage unit 212 and displays the tomographic image Gb based on this image data on the display unit 240A (S27). The image display mode in steps S25 to S27 is the same as that shown in FIG. 11, for example.

  Further, the main control unit 211 reads out the image data 212 a and 212 b of the fundus image and the image data Ga and Gb of the tomographic image from the image storage unit 212 and sends them to the image processing unit 230. The integrated image generation unit 234 integrates each of the tomographic image data 212a and 212b in the depth direction, and generates an integrated image corresponding to the first inspection date and an integrated image corresponding to the second inspection date and time, respectively. (S28). The integrated image displacement calculation unit 235 calculates the displacement in the xy direction of the integrated image corresponding to the first and second inspection dates (S29).

  Subsequently, the image position changing unit 236 aligns the tomographic images Ga and Gb in the xy directions based on the calculated displacement of the integrated image (S30).

  Further, the image position changing unit 236 calculates the displacement so that the correlation between the fundus images 212a and 212b is the highest, aligns the two fundus images based on the displacement, and uses the result of the alignment. Then, the tomographic images Ga and Gb are aligned in the xy direction (S31). The tomographic image alignment process using the integrated image is thus completed. The main control unit 211 can change the display positions of the images R and R ′ in the scanning region on the fundus image display unit 240a, as in the case of the alignment using the position information.

  In addition, since the alignment by the above integrated image is the alignment in the xy direction, the alignment in the z direction by the depth information similar to the case of the alignment process using the position information is performed, and the tomographic images Ga, Gb It is desirable to perform the three-dimensional alignment.

[Use example of alignment result]
The result of the alignment of tomographic images described above can be used as follows in the follow-up observation of the fundus oculi Ef.

(First use example)
First, an example of an image display mode using the tomographic image alignment result will be described. Here, it is assumed that m pieces of tomographic images (that is, a group of tomographic images) have been acquired at the first and second examination dates and times. The m pieces of tomographic images belonging to the tomographic image group at the first examination date and time are represented by symbols Ga1 to Gam, and the m pieces of tomographic images belonging to the tomographic image group at the second examination date and time are represented by the symbols Gb1 to Gbm. . Even if the number of tomographic image groups belonging to the two tomographic image groups is different, the same processing as described below can be performed.

  The processing by the image position changing unit 236 performs alignment between the tomographic images Ga1 to Gam at the first examination date and time and the tomographic images Gb1 to Gbm at the second examination date and time. Here, it is assumed that the intervals between adjacent tomographic images are set equal. That is, for each i = 1 to m−1, the interval between the tomographic image Gai and the tomographic image Ga (i + 1) is expressed as Δda, and the interval between the tomographic image Gbi and the tomographic image Gb (i + 1) is expressed as Δdb. , Δda = Δdb is set.

  At this time, the tomographic images Ga1 to Gam and the tomographic images Gb1 to Gbm are subjected to alignment between the tomographic image Gai and the tomographic image Gbi for each i = 1 to m by the image position conversion unit 236.

  In response to this alignment result, the main control unit 211 generates, for each i = 1 to m, image-related information that associates the tomographic image Gai on the first examination date and time with the tomographic image Gbi on the second examination date and time. Acts as follows. The generated image related information is stored in the information storage unit 213, for example.

  On the display screen of the display unit 240A shown in FIG. 11, a display screen switching unit (not shown) (including soft keys) for switching tomographic images to be displayed on the tomographic image display unit 240b is displayed. The operation of the related image switching unit is, for example, a click operation with the mouse 206 of the operation unit.

  When the tomographic image Gai of the first examination date and time (or the tomographic image Gbi of the second examination date and time) is displayed on the display screen switching unit, the other tomographic image Gaj (or the first tomographic image Gaj of the first examination date and time) is displayed. The same inspection image switching unit for switching the display to another tomographic image Gbj; j ≠ i) of the inspection date and time of 2 is provided. When the same inspection image switching unit is operated, for example, the display is switched to the next tomographic image Ga (i + 1). Further, for example, a desired one of the tomographic images Ga1 to Gam (or tomographic images Gb1 to Gbm) may be selected and displayed (specifically, for example, thumbnails of the tomographic images can be selected and displayed). It is possible to apply a configuration such as

  Furthermore, the display screen switching unit is provided with a related image switching unit for switching display to a tomographic image associated with the displayed tomographic image. That is, when the tomographic image Gai at the first examination date and time (or the tomographic image Gbi at the second examination date and time) is displayed, if the related image switching unit is operated, the second image associated with the tomographic image Gai is displayed. The display is switched to the tomographic image Gbi at the examination date and time (or the tomographic image Gai at the first examination date and time associated with the tomographic image Gbi).

  The user can display a tomographic image Gai (or tomographic image Gbi) of a desired cross section by operating the same examination image switching unit. Furthermore, the tomographic image Gbi (or tomographic image Gai) associated with the tomographic image Gai (or tomographic image Gbi) can be displayed by operating the related image switching unit. Further, the tomographic image Gai can be displayed again by operating the related image switching unit again. By switching the display image in this way, the tomographic image Gai and the tomographic image Gbi at substantially the same cross-sectional position can be alternately displayed, so that the state of the cross-sectional position (for example, the thickness of the retina) is temporally changed. Changes can be easily compared.

  As a modification of this display mode, a plurality of tomographic image display units 240b can be displayed side by side, one of which can display the tomographic image Gai, and the other can be configured to display the tomographic image Gbi. is there. Further, in response to the switching of the tomographic image displayed on one tomographic image display unit 240b by the same examination image switching unit, the tomographic image associated with the tomographic image is displayed on the other tomographic image display unit 240b. It is also possible to configure it.

(Second usage example)
Next, an example of image analysis processing using the alignment result of tomographic images will be described. In the follow-up observation, various indices related to the state of the fundus may be analyzed. An example of this index is the thickness of the retina. The thickness of the retina is obtained, for example, by calculating the difference between the z coordinate value of the retina surface and the z coordinate value of the retinal pigment epithelium layer in the tomographic image.

  Assume that for each i = 1 to m, a tomographic image Gai on the first examination date and time and a tomographic image Gbi on the second examination date and time are associated with each other. At this time, the main control unit 211 calculates the thickness of the retina at the cross-sectional position based on each tomographic image Gai, and calculates the thickness of the retina at the cross-sectional position based on each tomographic image Gbi.

  Further, the main controller 211 calculates the difference between the thickness of the retina based on the tomographic image Gai and the thickness of the retina based on the tomographic image Gbi for each cross-sectional position (that is, for each i = 1 to m). Thereby, a distribution of temporal changes in the thickness of the retina for each cross-sectional position is obtained. The main control unit 211 can cause the display unit 240b to display an image (distribution image) in which the obtained distribution is expressed in gradation, for example. The user can easily grasp the distribution state of the temporal change in the thickness of the retina in the fundus oculi Ef by viewing this distribution image.

[Action / Effect]
The operation and effect of the fundus oculi observation device 1 as described above will be described. The fundus oculi observation device 1 generates position information 213a indicating the position of the tomographic image Ga in the fundus image 212a for the fundus image 212a and the tomographic image Ga acquired at the first examination date and time, and at the second examination date and time. For the acquired fundus image 212b and tomographic image Gb, position information 213b indicating the position of the tomographic image Gb in the fundus image 212b is generated. Based on the position information 213a and 213b, the tomographic image Ga at the first examination date and time and the tomographic image Gb at the second examination date and time are aligned.

  More specifically, the fundus oculi observation device 1 uses the scanning area information and fixation position information included in the position information 213a and 213b to align the tomographic images Ga and Gb in the surface direction (xy direction) of the fundus oculi Ef. Act to do. Further, the alignment in the xy directions can be performed based on the alignment result of the accumulated images of the tomographic images Ga and Gb. Further, the depth information included in the position information 213a and 213b is used to perform alignment of the tomographic images Ga and Gb in the depth direction (z direction) of the fundus oculi Ef. By combining such alignment processing, three-dimensional alignment can be performed.

  Also, the fundus image 212a at the first examination date and time and the fundus image 212b at the second examination date and time are aligned, and based on the result, detailed alignment in the xy directions of the tomographic images Ga and Gb is performed. Works.

  As described above, according to the fundus oculi observation device 1 according to the present embodiment, the tomographic images Ga and Gb of the fundus oculi Ef having different examination dates and times can be suitably aligned, so that the process using the tomographic image of the fundus oculi Ef is performed. Observation can be performed effectively and efficiently.

[Modification]
The configuration detailed above is merely an example for favorably implementing the fundus oculi observation device according to the present invention. Therefore, arbitrary modifications within the scope of the present invention can be appropriately made. Hereinafter, some of such modifications will be described.

  The fundus oculi observation device 1 according to the above embodiment is configured to perform alignment of the fundus tomographic image based on each of the scanning region information, fixation position information, depth information, and integrated image. It is sufficient if it is configured to perform alignment based on one or more of these four according to the invention.

  In particular, it is sufficient that the alignment in the surface direction xy direction of the fundus is performed based on any one of the scanning area information, the fixation position information, and the integrated image. In addition, when performing alignment based only on the integrated image, it is sufficient to have only a configuration as an optical image measurement device (OCT device).

  The alignment of the tomographic image of the fundus is performed by combining the alignment in the xy direction based on the scanning area information, the fixation position information or the integrated image and the alignment in the z direction based on the depth information. It is desirable to improve the alignment accuracy by performing the three-dimensional alignment.

  In the above-described embodiment, the alignment processing of two acquired tomographic images has been described. However, the configuration of the above-described embodiment can also be applied to acquire a tomographic image of (substantially) the same part as a past examination. It is. Therefore, for example, based on the fixation position information in the past examination, the LCD 140 is controlled to display the internal fixation target at the same position as the past examination, and the eye to be examined is fixed in the same direction as the past examination. Let Further, the current fundus image is displayed, and an image indicating a scanning area based on the scanning area information in the past examination is displayed superimposed on the fundus image. At this time, the displacement between the fundus image in the past examination and the current fundus image is calculated (for example, the displacement when aligning so that the correlation is the highest is calculated), and the position moved according to this displacement To display the scanning area of the past examination. The position of the displayed scanning area is designated as the scanning area of the signal light LS in the current examination. Thereby, it is possible to designate the same scanning area as in the past inspection. Note that the fundus image and the scanning region are not necessarily displayed.

  The fundus oculi observation device according to the present invention has a fundus camera (unit) as a device for forming a two-dimensional image of the fundus surface. For example, any ophthalmologic device such as a slit lamp (slit lamp microscope device) is used. It is also possible to form a two-dimensional image of the fundus surface.

  In the above-described embodiment, the image forming unit 220 (image forming board 208) performs two-dimensional image and tomographic image formation processing on the surface of the fundus oculi Ef, and the control unit 210 (microprocessor 201 or the like) performs various control processes. However, both of these processes can be performed by one or a plurality of computers.

1 fundus observation apparatus 1A fundus camera unit 3a operation panel 301 menu switch 302 split switch 303 photographing light amount switch 304 observation light amount switch 305 chin rest switch 306 photographing switch 307 zoom switch 308 image changeover switch 309 fixation target changeover switch 310 fixation target position Adjustment switch 311 Fixation target size switching switch 312 Mode switching knob 8c Mounting unit 10, 12 Imaging device 100 Illumination optical system 101 Observation light source 103 Imaging light source 120 Imaging optical system 134, 136 Dichroic mirror 140 LCD
141 Scan unit 141A, 141B Galvano mirror 142 Lens 150 OCT unit 151 Connector part 152 Connection line 152a, 161, 163, 164, 165 Optical fiber 160 Low coherence light source 162 Optical coupler 174 Reference mirror 180 Spectrometer 184 CCD
200 Arithmetic Control Device 201 Microprocessor 208 Image Forming Board 208a Fundus Image Forming Board 208b OCT Image Forming Board 210 Control Unit 211 Main Control Unit 212 Image Storage Units 212a and 212b Fundus Image (Image Data)
213 Information storage unit 213a, 213b Position information 214 Position information generation unit 220 Image forming unit 230 Image processing unit 231 Scanning region displacement calculation unit 232 Fixation position displacement calculation unit 233 Depth position displacement calculation unit 234 Integrated image generation unit 235 Integrated image displacement Calculation unit 236 Image position changing unit 240 User interface 240A Display unit 240a Fundus image display unit 240b Tomographic image display unit 240B Operation units 241 and 242 Mirror drive mechanism 243 Reference mirror drive mechanism L0 Low coherence light LR Reference light LS Signal light LC Interference light R, R 'scanning regions R1-Rm scanning lines Rij (i = 1-m, j = 1-n) scanning points G, G1-Gm, Ga, Gb tomographic image (image data thereof)
Gij (i = 1 to m, j = 1 to n) Image E in the depth direction Eye Ef Examination fundus Ef ′ Fundus image (two-dimensional image of the surface of the fundus)
F, F 'fixation position

Claims (2)

Image forming means for detecting interference light between the signal light and the reference light via the fundus of the eye to be examined, and forming a tomographic image in the depth direction of the fundus based on the detection result;
Position information generating means for generating depth information indicating the position of the tomographic image in the depth direction based on the formed tomographic image;
Based on the depth information generated for the tomographic image formed earlier and the depth information generated for the tomographic image formed thereafter, the previous tomographic image and the subsequent tomographic image Image processing means for performing alignment in the depth direction;
Comprising
A fundus oculi observation device characterized by that. The depth information includes information expressing the position of a predetermined layer of the fundus in the tomographic image formed by the image forming unit, using coordinates set in advance on the tomographic image,
The image processing means matches the coordinates corresponding to the previous tomographic image with the coordinates corresponding to the subsequent tomographic image, so that the depths of the previous tomographic image and the subsequent tomographic image are the same. Align in the direction,
The fundus oculi observation device according to claim 1.

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