JP2019076445A - Optical coherence tomographic apparatus, image processing apparatus, and image processing method - Google Patents

Abstract

To accurately orientate a cross section of a specific portion of a sieve-like plate, etc.SOLUTION: An optical coherence tomographic apparatus includes a cross-section setting unit which uses partial image data, a portion of three-dimensional image data of a subject eye acquired using optical coherence tomography to set a cross section to the three-dimensional image data. The cross-section setting unit identifies an end part of a layer boundary of the subject eye in the three-dimensional image data, and sets the orientation of the cross section using information relevant to the identified end part.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an optical coherence tomography apparatus, an image processing apparatus, and a method thereof.

  At present, various types of ophthalmic instruments using optical instruments are used. For example, as an optical apparatus for observing an eye, various apparatuses such as an anterior segment imaging apparatus, an eye fundus camera, a confocal laser scanning ophthalmoscope (SLO), and the like are used. Among them, an optical coherence tomography apparatus based on optical coherence tomography (OCT) using multi-wavelength light wave interference is an apparatus capable of obtaining a tomographic image of a sample with high resolution. For this reason, it is becoming an indispensable device in the specialist outpatient department of the retina as an ophthalmic apparatus. Moreover, it is used not only for ophthalmology but also for endoscopes and the like. Hereinafter, this is referred to as an OCT apparatus. The OCT apparatus is widely used in ophthalmologic diagnosis and the like to acquire a tomogram of a retina on the fundus of an eye to be examined and a tomogram of an anterior segment such as a cornea.

  The OCT apparatus divides measurement light, which is low coherent light, into reference light and measurement light, irradiates the measurement light to the object to be inspected, causes the return light from the object to be inspected to interfere with the reference light, and It is possible to measure the fault of the object from the spectral information. In current OCT apparatuses, spectrum domain OCT (SD-OCT) that can obtain information in the depth direction from the spectrum information of the interference light described above is generally used. Furthermore, wavelength sweeping OCT (Swept Source OCT: SS-OCT) using a wavelength variable light source device capable of changing the oscillation wavelength as a light source is also used. SD-OCT and SS-OCT are collectively referred to as Fourier domain OCT (FD-OCT).

  Here, the observation of the lamina cribrosa in the optic disc region of the fundus of the eye to be examined is useful for ophthalmologic diagnosis such as glaucoma. Therefore, Patent Document 1 discloses a technique for setting the position and orientation of the cross section of the sieve plate by manually specifying the sieve plate area or automatically detecting the sieve plate area.

JP, 2016-179402, A

  At this time, the sieved plate may not be imaged with high accuracy in the tomographic image. In such a case, it is also difficult to set the direction of the cross section of the sieve plate, since it is difficult to manually designate the sieve plate region in the tomographic image or to automatically detect the sieve region itself.

  One of the objects of the present invention is to accurately set the direction of the cross section of a specific part such as a sieve plate.

In order to achieve the above object, one of the optical coherence tomography apparatuses according to the present invention is
An acquisition unit that acquires three-dimensional image data of an eye to be examined by using optical coherence tomography;
A designation unit for designating partial image data which is a part of the three-dimensional image data corresponding to a specific part of the eye to be examined;
A cross section setting unit that sets a cross section for the three-dimensional image data using the partial image data;
Have
The cross-section setting unit specifies an end of a layer boundary of the eye to be examined in the three-dimensional image data, and sets an orientation of the cross-section using information on the specified end.

  According to one of the present invention, the direction of the cross section of a specific part such as a sieve plate can be set with high accuracy.

It is a whole block diagram of a present Example. It is explanatory drawing of the measurement optical system of a present Example. It is explanatory drawing of the edge part of the layer boundary detected in a present Example. It is explanatory drawing which sets a cross section from the edge part of a layer boundary in a present Example. It is a flowchart of a present Example. It is explanatory drawing which extracts the edge part of a layer boundary from the information of a front image in a present Example.

  The present invention will be described in detail based on the illustrated embodiments.

(Body configuration)
FIG. 1 is a side view of the optical coherence tomography in the present embodiment. Reference numeral 100 denotes a measurement optical system for acquiring an anterior segment image, an SLO fundus image of an eye to be examined, and a tomographic image. Reference numeral 101 denotes a stage unit capable of moving the measurement optical system 100 back and forth and right and left. Reference numeral 102 denotes a base unit incorporating a spectroscope described later. A personal computer 103 performs control of the stage unit, control of the alignment operation, and formation of a tomographic image. A storage unit 104 stores a tomographic imaging program, patient information, imaging data, statistical information of a normal database, and the like. Reference numeral 105 denotes an input unit for giving an instruction to the personal computer, and more specifically, the input unit 105 includes a keyboard and a mouse. Reference numeral 106 denotes a display unit such as a monitor. The personal computer 103 is an example of an acquisition unit, a designation unit, a cross section setting unit, a formation unit, a display control unit, and the like, which will be described later. Here, the acquisition unit acquires three-dimensional image data of the eye to be examined by using optical coherence tomography. Further, the designation unit is for designating partial image data which is a part of three-dimensional image data corresponding to a specific part (for example, a sieve plate) of an eye to be examined. Also, the cross-section setting unit sets a cross-section for three-dimensional image data using partial image data. Also, the forming unit forms cross-sectional image data representing the set cross section. In addition, the display control unit causes the display unit 106 to display an image based on the cross-sectional image data. A personal computer is an example of an image processing apparatus that executes each of these functions. The image processing apparatus may be connected to the optical coherence tomography apparatus in a communicable manner, and may be incorporated inside the optical interference tomography apparatus.

(Configuration of measurement optical system and spectroscope)
The configuration of the measurement optical system and the spectroscope of this embodiment will be described with reference to FIG. First, the inside of the measurement optical system 100 will be described. An objective lens 201 is disposed to face the eye 200 to be examined, and a first dichroic mirror 202 and a second dichroic mirror 203 are disposed on the optical axis of the objective lens 201. With these dichroic mirrors, the optical path 250 of the OCT optical system, the SLO optical system that combines observation of the eye to be examined and acquisition of the SLO fundus image, the optical path 251 for the fixation lamp, and the optical path 252 for anterior eye observation It branches for every. The SLO optical system and the optical path 251 for the fixation lamp include SLO scanning means 204, lenses 205 and 206, a mirror 207, a third dichroic mirror 208, a photodiode 209, an SLO light source 210, and a fixation lamp 211. The mirror 207 is a prism on which a perforated mirror or a hollow mirror is vapor-deposited, and separates illumination light from the SLO light source 210 and return light from the eye to be examined. The third dichroic mirror 208 splits the wavelength path into the light path to the SLO light source 210 and the fixation lamp 211. The SLO scanning means 204 scans the light emitted from the SLO light source 210 and the fixation lamp 211 on the subject eye 200, and comprises an X scanner for scanning in the X direction and a Y scanner for scanning in the Y direction. There is. In this embodiment, since the X scanner needs to perform high-speed scanning, the Y scanner is configured by a galvano mirror by a polygon mirror. The lens 205 is driven by a motor (not shown) to focus the SLO optical system and the fixation lamp. The SLO light source 210 generates light of a wavelength near 780 nm. The photodiode 209 detects return light from the subject's eye. The fixation lamp 211 generates visible light to promote fixation of the subject.

  The light emitted from the SLO light source 210 is reflected by the third dichroic mirror 208, passes through the mirror 207, passes through the lenses 206 and 205, and is scanned on the subject eye 200 by the SLO scanning means 204. The return light from the subject eye 200 returns along the same path as the projection light, is reflected by the mirror 207, is guided to the photodiode 209, and an SLO fundus image is obtained. The light emitted from the fixation lamp 211 passes through the third dichroic mirror 208 and the mirror 207, passes through the lenses 206 and 205, and is scanned on the subject eye 200 by the SLO scanning unit 204. At this time, by causing the fixation lamp 211 to blink in accordance with the movement of the SLO scanning means, an arbitrary shape is formed at an arbitrary position on the subject's eye 200 to promote fixation of the subject.

  In an optical path 252 for anterior eye observation, lenses 212 and 213, a split prism 214, and a CCD 215 for anterior eye portion observation for detecting infrared light are disposed. The CCD 215 is sensitive to the wavelength of the irradiation light for anterior eye observation (not shown), specifically, around 970 nm. The split prism 214 is disposed at a position conjugate to the pupil of the subject eye 200, and can detect the distance in the Z direction (front-back direction) of the measurement optical system 100 to the subject eye 200 as a split image of the anterior segment. it can.

  The optical path 250 of the OCT optical system constitutes the OCT optical system as described above, and is for capturing a tomographic image of the eye 200 to be examined. More specifically, an interference signal for forming a tomographic image is obtained. An XY scanner 216 scans light on the subject's eye. Although the XY scanner 216 is illustrated as a single mirror, it is a galvano mirror that performs scanning in the XY two-axis direction. Reference numerals 217 and 218 denote lenses, of which the lens 217 is driven by a motor (not shown) to focus light from the OCT light source 220 emitted from the fiber 224 connected to the optical coupler 219 to the eye 200. Ru. By this focusing, the return light from the eye 200 to be examined is simultaneously imaged and incident on the tip of the fiber 224 in the form of a spot.

  Next, the configuration of the optical path from the OCT light source 220, the reference optical system, and the spectroscope will be described. 220 is an OCT light source, 221 is a reference mirror, 222 is a dispersion compensating glass, 223 is a lens, 219 is an optical coupler, 224 to 227 are single-mode optical fibers connected and integrated to the optical coupler, 230 is a spectroscope is there. The Michelson interference system is configured by these configurations. The light emitted from the OCT light source 220 is divided through the optical fiber 225 into measurement light on the optical fiber 224 side and reference light on the optical fiber 226 side via the optical coupler 219. The measurement light is irradiated to the eye 200 to be observed through the OCT optical system optical path described above, and reaches the optical coupler 219 through the same optical path by reflection and scattering by the eye. On the other hand, the reference light reaches and is reflected by the reference mirror 221 through the optical fiber 226, the lens 223, and the dispersion compensation glass 222 inserted to match the dispersion of the measurement light and the reference light. Then, the same light path is returned to reach the light coupler 219. The measurement light and the reference light are combined by the optical coupler 219 and become interference light. Here, interference occurs when the optical path length of the measurement light and the optical path length of the reference light become substantially the same. The reference mirror 221 is adjustably held in the optical axis direction by a motor and a drive mechanism (not shown), and can adjust the optical path length of the reference light to the optical path length of the measurement light which changes depending on the eye 200 to be examined. The interference light is guided to the spectroscope 230 via the optical fiber 227. Reference numeral 228 denotes a polarization adjustment unit provided in the optical fiber 224 on the measurement light side. Reference numeral 229 denotes a polarization adjustment unit on the reference light side provided in the optical fiber 226. These polarization control parts have some parts in which optical fibers are looped. By twisting the loop portion by rotating it around the longitudinal direction of the fiber, it is possible to apply twist to the fiber and adjust and match the polarization states of the measurement light and the reference light. The spectroscope 230 includes lenses 232 and 234, a diffraction grating 233, and a line sensor 231. The interference light emitted from the optical fiber 227 is collimated through the lens 234, and then separated by the diffraction grating 233 and imaged on the line sensor 231 by the lens 232.

  Next, the periphery of the OCT light source 220 will be described. The OCT light source 220 is SLD (Super Luminescent Diode) which is a typical low coherent light source. The central wavelength is 855 nm, and the wavelength bandwidth is about 100 nm. Here, the bandwidth is an important parameter because it affects the resolution in the optical axis direction of the obtained tomographic image. Although the SLD is selected as the type of light source here, low coherent light may be emitted, and ASE (Amplified Spontaneous Emission) or the like can be used. The central wavelength is preferably near infrared light in view of measuring the eye. In addition, since the central wavelength affects the lateral resolution of the obtained tomographic image, it is desirable that the central wavelength be as short as possible. The center wavelength is 855 nm for both reasons. In the present embodiment, the Michelson interference system is used as the interference system, but a Mach-Zehnder interference system may be used. It is desirable to use a Mach-Zehnder interference system when the light amount difference is large and a Michelson interference system when the light amount difference is relatively small according to the light amount difference between the measurement light and the reference light.

  With the above-described configuration, a tomographic image of the eye to be examined can be acquired, and even with near-infrared light, an SLO fundus image of the eye to be inspected having high contrast can be acquired.

(Imaging method of tomographic image)
A method of imaging a tomographic image using an optical coherence tomography apparatus will be described. The optical coherence tomography apparatus can capture a tomographic image of a predetermined part of the eye 200 by controlling the XY scanner 216. Here, a trajectory of scanning the tomographic image acquisition light in the eye to be examined is called a scan pattern (scan pattern). The scan pattern includes, for example, a cross scan in which scanning is performed around a point in a cross direction, a 3D scan in which a scan is performed so as to fill the entire area, and a three-dimensional tomographic image is obtained as a result. Cross-scan is suitable for detailed observation at a specific site, and 3D scan is suitable for observing the layer structure or layer thickness of the entire retina.

  Here, an imaging method when 3D scanning is performed will be described. First, scanning (scanning) of measurement light is performed in the X direction in the drawing, and information of a predetermined number of imagings is imaged by the line sensor 231 from the imaging range in the X direction in the eye to be examined. The acquisition unit performs Fast Fourier Transform (FFT) on the luminance distribution on the line sensor 231 obtained at a certain position in the X direction, and displays the linear luminance distribution obtained by the FFT on the monitor 106. Convert to information. This is called an A-scan image. Further, a two-dimensional image in which the plurality of A-scan images are arranged is referred to as a B-scan image. After capturing a plurality of A-scan images for constructing one B-scan image, a plurality of B-scan images are obtained by moving the scan position in the Y direction and performing the scan in the X direction again. By displaying a plurality of B-scan images or a three-dimensional tomographic image constructed from a plurality of B-scan images on the monitor 106, the examiner can diagnose the eye to be examined. Here, an example is shown in which a three-dimensional tomographic image (three-dimensional image data) is obtained by obtaining a plurality of B-scan images in the X direction, but a three-dimensional tomographic image is obtained by obtaining a plurality of B-scan images in the Y direction. It is also good.

(Specifying a partial image)
Further, in the present embodiment, as shown in FIG. 3, the designation unit aims to observe the lamina crib A3 present in the deep layer of the optic disc, and thus a partial image (partial image data) including the lamina crib Specify At this time, the designation unit can automatically select a partial image which is a part of three-dimensional image data by using a known detection algorithm of the optic disc. That is, the specification unit can automatically specify partial image data by analyzing three-dimensional image data. Further, the designation unit may manually designate partial image data by the operation of the user. That is, the designation unit may designate partial image data in accordance with the user's operation.

(Extraction of layer boundary)
Also, the forming unit applies a median filter and a Sobel filter to the B-scan image to generate an image. The generated images are referred to as median image and Sobel image, respectively. Next, a profile is generated for each A scan from the median image and the Sobel image. For median images, profiles of intensity values are generated, and for Sobel images, profiles of gradients are generated. Then, the peaks in the profile generated from the Sobel image are extracted. The boundary of each region of the retinal layer is extracted by referring to the profile of the median image corresponding to the front and back of the extracted peak or between the peaks. Here, in the present embodiment, as shown in FIG. 3, the layer boundary extraction unit includes the inner limiting membrane (ILM) L1, the boundary L2 of the nerve fiber layer (NFL) A1, and the boundary L3 of the retinal pigment epithelial layer (RPE). , L4 to extract.

(Identify the end of the layer boundary)
In addition, the cross-section setting unit specifies an end of the extracted layer boundary in each B-scan image. Here, in the present embodiment, as shown in FIG. 3, the cross-sectional setting unit specifies Bruch's membrane openings (BMO) P1 and P2 as the end of the layer boundary. At this time, the optic disc depression is identified using the boundary L4 of ILM · L1 and RPE. The features of the optic disc depression include the absence of NFL A1 and the shape of ILM L1 having a large gradient in the depth direction (z direction in FIG. 3). Therefore, a local region including each A scan and its peripheral A scan is set, and the existence status of NFL · A1 in the local region and the gradient of ILM · L1 in the depth direction are calculated. Identify points near the center. Here, a point near the center of the optic disc depression is an example of information on the identified optic disc. In addition, in each B scan image, by connecting the points of the RPE boundary L4 close to the optic disc depression in all the B scan images, an RPE region having an elliptical shape when viewed in the C scan direction is set. . The BMO ends P1 and P2 are specified in each B-scan image by applying an active contour model such as Snakes or LevelSet with the position as an initial position. Next, from the BMO ends P1 and P2 specified above, the edge component is traced toward the center of the optic disc recess, and the exact position of the BMO ends P1 and P2 is specified.

  In the present embodiment, first, coordinate values and edge components are examined for each BMO end. Next, with the position of each BMO end as a starting point, the edge is traced toward the center of the optic disc depression. The trace refers to the edge component at the position of each BMO end, updates the search point to the position where the edge component present in the inner neighborhood is closest, and also updates the referenced edge component. By repeating this, the correct BMO end is identified. In the present embodiment, the BMO end is used as the end of the layer boundary, but the end of another layer boundary such as the end P3, P4 of the boundary L2 of the NFL · A1 shown in FIG. 3 may be used. .

(Setting the orientation of the cross section)
In addition, the cross section setting unit sets the direction of the cross section from the BMO end specified in each B scan image. That is, the cross section setting unit sets the direction of the cross section using the information on the identified end. Here, in the present embodiment, as shown in FIG. 4, the cross-section setting unit uses the least squares method to minimize the sum of squares of the distances from the BMO end specified in each B-scan image. Set the orientation of Note that the cross-section setting unit may select three points out of the BMO ends specified in each B-scan image, and set the direction of the cross-section using information on the inclination angle of the plane formed by the selected three points. .

(Formation of cross-sectional image data and display of image based on cross-sectional image data)
Further, the cross-section setting unit sets a cross-section moved a predetermined distance in the depth direction perpendicular to the cross-section set from the BMO end as the position of the cross-section. Then, the forming unit forms cross-sectional image data representing the set cross section. Here, when the sieved plate A3 can be extracted, the forming unit may extract the sieved plate A3 and form cross-sectional image data using the cross section moved to the sieved plate A3 extracted. Further, the display control unit causes the display unit 106 to display an image based on the formed cross-sectional image data. At this time, the user can also change (correct) at least one of the position and the orientation of the cross section while checking the image displayed on the display unit 106. That is, the designation unit can change at least one of the position and the orientation of the cross section in accordance with the user's operation while the image based on the formed cross-sectional image data is displayed on the display unit.

(Processing flow)
The processing flow of the present embodiment will be described with reference to the flowchart of FIG. First, in step S501, as shown in FIG. 3, the designation unit designates a partial image including a lamina cribosa plate for the purpose of observing the lamina cribrosa plate A3 present in the deep layer of the optic disc. In step S502, as shown in FIG. 3, the layer boundary extraction unit includes the inner limiting membrane (ILM) L1, the boundary L2 of the nerve fiber layer (NFL) A1, the boundaries L3 and L4 of the retinal pigment epithelial layer (RPE). Extract Further, in step S503, the cross-section setting unit specifies the Bruch film openings (BMO) P1 and P2 as the end of the layer boundary from the extracted layer boundary in each B-scan image. In step S504, the section setting unit sets the direction of the section from the end of the BMO specified in each B-scan image. Further, in step S505, the forming unit forms cross-sectional image data using a cross section moved a predetermined distance in the depth direction perpendicular to the cross section set from the BMO end. In step S506, the display control unit causes the display unit 106 to display an image based on the formed cross-sectional image data.

(Identify the end of the layer boundary from the information of the frontal image)
As shown in FIG. 6, in the B-scan image, identification of the BMO end may be difficult due to the influence of blood vessels in the shallow layer and the like. In this case, as shown in FIG. 6, the BMO end may be specified using information of a front image such as a projection image, an Enface image, or an SLO image. First, the optic disc region A4 is extracted from the front image. Since the optic disc region A4 is darker than the surrounding area and has an elliptical shape, the boundary L5 of the optic disc region is extracted by thresholding and elliptical approximation. The boundary L5 of the optic disc region is an example of information regarding the identified optic papilla. Further, positions P5 and P6 corresponding to the B-scan image are specified on the front image. Further, broken lines L6 and L7 are set at positions corresponding to P5 and P6 specified on the front image on the B-scan image. Here, similar to the specification of the end of the layer boundary, the coordinate value and the edge component are examined with respect to the point of the boundary L4 of the RPE, and the edge is traced toward the center of the optic disc depression. Then, after tracing to a point where tracing can not be performed due to the influence of blood vessels in the shallow layer, and the like, tracing points immediately before that point and the intersection points of the broken lines L6 and L7 are extracted. By this method, even if accurate BMO end identification can not be performed, the approximate position of the BMO end can be identified.

  Further, in the setting of the orientation of the cross section, the least square method is used to set the orientation of the cross section such that the sum of squares of distances from the specified BMO end is minimized. For this reason, although some BMO ends can not be identified accurately, even if the approximate position is used, there is no significant influence on the cross section setting. In addition, even if the optimal cross section can not be set by using the approximate position of the BMO end, the cross section is close to the optimal cross section, so cross-sectional image data displayed on the display unit 106 is confirmed, The user can change the cross section to an optimum one.

(Other embodiments)
Here, in the present embodiment, SD-OCT has been described, but SS-OCT can be configured in the same manner. The present invention is also realized by executing the following processing. That is, software (program) for realizing the functions of the above-described embodiment is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU or the like) of the system or apparatus reads the program. The processing to be performed also constitutes an aspect of the present invention.

Claims (19)

An acquisition unit that acquires three-dimensional image data of an eye to be examined by using optical coherence tomography;
A designation unit for designating partial image data which is a part of the three-dimensional image data corresponding to a specific part of the eye to be examined;
A cross section setting unit that sets a cross section for the three-dimensional image data using the partial image data;
Have
The cross section setting unit specifies an end of a layer boundary of the eye to be examined in the three-dimensional image data, and sets an orientation of the cross section using information on the specified end. Tomography device.   The optical coherence tomography apparatus according to claim 1, wherein the cross-section setting unit sets the direction of the cross-section using information on an inclination angle of a surface formed by the specified end.   The light interference according to claim 1 or 2, wherein the cross-section setting unit identifies an end of a layer boundary of the eye to be examined in the three-dimensional image data by analyzing the three-dimensional image data. Tomography device.   The cross-section setting unit identifies the optic disc region of the subject eye by analyzing the three-dimensional image data, and uses the information on the identified optic disc region to identify the layer of the subject eye in the three-dimensional image data. The optical coherence tomography apparatus according to claim 3, wherein an end of the boundary is identified.   3. The light according to claim 1, wherein the cross-section setting unit specifies an end of a layer boundary of the eye in the three-dimensional image data using information of a front image of the eye. Interference tomography apparatus.   The cross-section setting unit identifies an optic disc region of the subject eye using information of a front image of the subject eye, and uses information of the identified optic disc region for the eye to be examined in the three-dimensional image data. 6. The optical coherence tomography apparatus according to claim 5, wherein an end of the layer boundary is specified. A forming unit for forming cross-sectional image data representing the set cross section;
A display control unit that causes a display unit to display an image based on the cross-sectional image data;
The optical coherence tomography apparatus according to any one of claims 1 to 6, further comprising:   8. The apparatus according to claim 7, wherein the designation unit changes at least one of the position and the orientation of the cross section in accordance with a user's operation in a state where the image is displayed on the display unit. Optical coherence tomography.   The optical coherence tomography apparatus according to any one of claims 1 to 8, wherein the end is a Bruch film opening.   The optical coherence tomography apparatus according to any one of claims 1 to 9, wherein the specific region is a sieve plate of the eye to be examined.   The optical coherence tomography apparatus according to any one of claims 1 to 10, wherein the designation unit designates the partial image data according to a user's operation.   The optical coherence tomography apparatus according to any one of claims 1 to 10, wherein the specification unit automatically specifies the partial image data by analyzing the three-dimensional image data. It has a cross-section setting unit that sets a cross-section for the three-dimensional image data using partial image data that is a part of the three-dimensional image data of an eye to be examined obtained by using optical coherence tomography.
The cross section setting unit identifies an end of a layer boundary of the eye to be examined in the three-dimensional image data, and sets an orientation of the cross section using information on the identified end. apparatus.   The image processing apparatus according to claim 13, wherein the cross-section setting unit sets the direction of the cross-section using information on an inclination angle of a surface formed by the identified end. A forming unit for forming cross-sectional image data representing the set cross section;
A display control unit that causes a display unit to display an image based on the cross-sectional image data;
The image processing apparatus according to claim 13, further comprising: Setting a cross section for the three-dimensional image data using partial image data that is a part of the three-dimensional image data of the subject eye obtained by using optical coherence tomography,
In the step of setting the cross section, the end of the layer boundary of the eye to be examined in the three-dimensional image data is specified, and the direction of the cross is set using information on the specified end. Image processing method.   The image processing method according to claim 16, wherein in the step of setting the cross section, the direction of the cross section is set using information on an inclination angle of a surface formed by the specified end. Forming cross-sectional image data representing the set cross section;
Displaying an image based on the cross-sectional image data on a display unit;
The image processing method according to claim 16, further comprising:   A program that causes a computer to execute the image processing method according to any one of claims 16 to 18.

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