Ophthalmic imaging device, method for controlling ophthalmic imaging device, and program

Abstract

To provide a device and a method capable of imaging or analyzing a subject being a vitreous opacity portion.SOLUTION: An ophthalmic imaging device includes: an imaging head including a measurement light source that emits measurement light; a scan optical system that scans intraocular portion of a subject eye with the measurement light according to predetermined scan information; and a light reception optical system that receives return light of the measurement light from the subject eye to generate a light reception signal; image generation means that generates an image by using the scan information and the light reception signal; storage means that stores a plurality of images that are the generated images, are related to the same subject eye under predetermined motion, and are of the same type; means that detects the predetermined motion on the basis of the stored images; and extraction means that extracts, by using at least two of the stored images, information regarding a movable body that is induced by the predetermined motion to perform a motion different from the detected predetermined motion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an ophthalmic imaging apparatus, a control method for an ophthalmic imaging apparatus, and a program. [Background technology]

[0002] As ophthalmic devices, fundus cameras and scanning laser ophthalmoscopes (SLO) have been put to practical use as devices for acquiring two-dimensional images of the fundus of the examinee's eye. Devices for acquiring tomographic images of the examinee's eye using optical coherence tomography (OCT) with low-coherent light (hereinafter referred to as OCT devices) have also been put to practical use. Furthermore, a combined device of an SLO device and an OCT device is also useful.

[0003] Meanwhile, the vitreous body, an intraocular tissue, is normally a colorless, transparent, jelly-like substance. However, it is known that, for example, with aging, it changes and liquefies, or develops slight opacity. Such opacified areas scatter and reflect measurement light, so even conventional SLO and OCT devices can capture these. However, such vitreous opacities and other intraocular floaters are generally considered to be obstacles to the observation and imaging of the retina. Regarding such opacified areas of the vitreous body (hereinafter referred to as "vitreous opacified areas"), a method disclosed in Patent Document 1, which avoids the vitreous opacity while observing the retina, and a method disclosed in Patent Document 2, which quantifies the impact of opacity, are known. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-336501 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-085176 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, fundus observation is performed taking into consideration the influence of vitreous opacity on the vitreous, but no device or method exists for photographing or analyzing the vitreous opacity.

[0006] One embodiment of the present invention has been made in consideration of the above-mentioned circumstances, and one of its objects is to provide an apparatus and method capable of photographing or analyzing vitreous opacity sites. [Means for solving the problem]

[0007] An ophthalmic imaging apparatus according to an embodiment of the present invention comprises: an imaging head including a measurement light source that emits measurement light, a scanning optical system that scans the interior of the subject's eye with the measurement light in accordance with predetermined scanning information, and a light receiving optical system that receives return light of the measurement light from the subject's eye and generates a light receiving signal; an image generating means for generating an image using the scanning information and the light receiving signal; a storage means for storing a plurality of images of the same type relating to the same subject's eye under a predetermined movement, the images being generated; means for detecting the predetermined movement based on the stored images; of the subject's eye vitreous exists within Opaque area The robot is induced by the predetermined movement to move in a manner different from the detected predetermined movement. Area where opacity exists using at least two of the stored plurality of images. Identify , the above Movement of opacified area information about the image using at least two of the stored images. calculation do calculation Means and Equipped with. [Effects of the Invention]

[0008] According to one embodiment of the present invention, it becomes possible to photograph or analyze a site of vitreous opacity as a target. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating an example of a schematic configuration of an ophthalmologic imaging apparatus according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram showing a schematic optical configuration of an imaging head according to the first embodiment. [Figure 3] 3 is a flowchart showing a series of processes of an analysis method according to the first embodiment. [Figure 4] FIG. 10 is a schematic diagram showing an example of a patient / examination selection screen. [Figure 5] FIG. 10 is a schematic diagram showing an example of an OCT examination screen. [Figure 6] FIG. 10 is a schematic diagram showing an example of a VTM examination screen. [Figure 7] FIG. 10 is a schematic diagram showing an example of a screen for setting shooting parameters. [Figure 8] 10 is a flowchart showing a series of processes performed during SLO video playback. [Figure 9] 10 is a timing chart showing the operation of each part and the state of a moving object when capturing an SLO moving image. [Figure 10] FIG. 10 is a schematic diagram showing an example of an analysis screen. [Figure 11] 10 is a flowchart showing a series of processes performed during analysis processing. [Figure 12] 10 is a flowchart showing a part of the processing of an analysis method according to a second embodiment. [Figure 13(a)] FIG. 10 is a schematic diagram showing an example of a VTM examination screen in the second embodiment. [Figure 13(b)] FIG. 10 is a schematic diagram showing an example of a VTM examination screen in the second embodiment. [Figure 14] 1A and 1B are schematic diagrams illustrating the relationship between tomographic images obtained when sequential scanning is performed. [Figure 15(a)] FIG. 10 is a schematic diagram showing a modified example of the analysis screen. [Figure 15(b)] FIG. 10 is a schematic diagram showing a modified example of the analysis screen. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, exemplary embodiments for carrying out the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of components described in the following embodiments are arbitrary and can be changed depending on the configuration of the device to which the present invention is applied or various conditions. In addition, the same reference numerals are used between the drawings to indicate identical or functionally similar elements.

[0011] (First Example) An ophthalmic imaging apparatus and a control method thereof according to a first preferred embodiment of the present invention will be described below with reference to the accompanying drawings. The ophthalmic imaging apparatus according to this embodiment is shown as one aspect of an ophthalmic imaging apparatus that uses an acquired image to extract, from the image, a moving object that is induced by the movement of the subject's eye, such as a vitreous opacity site, and that moves differently from the subject's eye.

[0012] Fig. 1 shows an example of a schematic configuration of an ophthalmic imaging apparatus according to a first embodiment of the present invention, where Fig. 1(a) is a diagram showing the configuration of the ophthalmic imaging apparatus, and Fig. 1(b) is a block diagram showing the functional configuration of a control device 120 shown in Fig. 1(a).

[0013] The ophthalmic imaging apparatus according to the first embodiment includes an imaging head 110 (imaging device), a control device 120, a display unit 130, and an input unit 140. In this embodiment, the ophthalmic image processing apparatus is included in the control device 120. The input unit 140 is composed of a keyboard, a pointing device, etc. that act as a GUI in cooperation with the display unit 130. The imaging head 110 incorporates an optical system for imaging a predetermined portion of the subject's eye, and is configured integrally with a stage provided with an alignment mechanism that can move in three axial directions (up and down, left and right, and front and back) for aligning the imaging head with respect to the subject's eye.

[0014] The control device 120 is communicatively connected to each of the imaging head 110, the display unit 130, and the input unit 140, and can control these. The control device 120 further generates and stores images from the imaging signals of the subject's eye acquired by the imaging head 110, and displays the stored images and related information on the display unit 130. In this embodiment, the imaging head 110 has a built-in speaker that serves as an instruction generating unit (described later) that generates instructions to induce eye movement, and also functions as an audio interface that generates necessary instructions to the subject in accordance with instructions from the control device 120.

[0015] The control device 120 can be configured using any general-purpose computer, but may also be configured using a dedicated computer provided in the ophthalmic imaging device. The display unit 130 can be configured using any display, but may also be configured as a touch panel having functions integrated with the input unit 140. In this embodiment, the imaging head 110, the control device 120, and the display unit 130 are provided separately, but they may also be provided integrally.

[0016] <Explanation of the imaging head 110 optical system> First, a description will be given of the configuration of the imaging head 110. Figure 2 is a schematic diagram showing an example of the optical configuration of the imaging head 110.

[0017] In the imaging head 110, an objective lens 211 shared by both the SLO optical system and the OCT optical system is disposed facing the subject's eye E. A first dichroic mirror 212, a second dichroic mirror 213, and a beam splitter 210 are disposed on the optical axis of the objective lens 211. These optical components cause the optical axis of the objective lens 211 to branch into an OCT optical path L1, an SLO optical path L2, an anterior segment observation optical path L3, and a fixation lamp optical path L4. The OCT optical path L1 is an optical path for capturing tomographic images of the fundus of the subject's eye and the vitreous body adjacent thereto, and the SLO optical path L2 is an optical path for capturing a frontal image of the fundus. The anterior segment observation optical path L3 is an optical path for observing the anterior segment, and the fixation lamp optical path L4 is an optical path for presenting a fixation lamp to encourage the subject's eye E to fixate.

[0018] The first dichroic mirror 212 branches an anterior-eye-segment observation optical path L3 from the optical axis of the objective lens 211 in the reflection direction according to the wavelength band of each light ray. The second dichroic mirror 213 branches an OCT optical path L1 from the optical axis of the objective lens 211 in the reflection direction according to the wavelength band of each light ray. The beam splitter 210 branches a fixation lamp optical path L4 from the optical axis of the objective lens 211 in the reflection direction and an SLO optical path L2 in the transmission direction according to the wavelength band. Note that the optical paths provided in the transmission direction and reflection direction of each dichroic mirror etc. may be reversed.

[0019] The SLO optical path L2 includes an SLO scanning means 214, a focus lens 215, and a lens 216, which are shared by an SLO scanning optical system for scanning the interior of the subject's eye while irradiating it with SLO measurement light, and a light receiving optical system for receiving return light from the subject's eye E. A partial reflection mirror 217 is provided at a position conjugate with the subject's eye pupil behind the lens 216 (in the opposite direction on the optical path with respect to the lens 216 from the objective lens 211). The partial reflection mirror 217 reflects the SLO measurement light emitted from the SLO measurement light source 221 at the center of the optical axis, and transmits return light from the subject's eye E in other regions. The partial reflection mirror 217 separates the SLO measurement light and the return light in the form of a beam splitter.

[0020] The system extending from the SLO measurement light source 221 provided in the reflected light path of the partial reflection mirror 217 to the objective lens 211 as described above is the SLO scanning optical system. The SLO scanning optical system scans the fundus of the subject's eye with the SLO measurement light. On the other hand, the system extending from the objective lens 211 to the SLO photodiode 220 provided in the transmitted light path of the partial reflection mirror 217 is the SLO light receiving optical system. The returned light from the subject's eye E guided to the SLO photodiode 220 by the SLO light receiving optical system is transmitted to the control device 120 as an SLO light receiving signal.

[0021] The SLO scanning means 214, which is shared by the SLO scanning optical system and the light receiving optical system, two-dimensionally scans the fundus of the subject's eye with SLO measurement light emitted from the SLO measurement light source 221. The SLO scanning means 214 is also used to guide return light from each scanning position to the SLO photodiode 220. The SLO scanning means 214 is composed of an X scanner that scans the SLO measurement light in the X direction and a Y scanner that scans in the Y direction. In this embodiment, the X scanner uses a polygon mirror because high-speed scanning is required, and the Y scanner uses a galvanometer mirror because low-speed scanning is sufficient.

[0022] The focus lens 215 is driven by a motor (not shown) in the direction indicated by the arrow in the figure for focus adjustment. The SLO measurement light source 221 is a light source that combines and emits lasers of four different wavelengths, for example, blue, green, red, and infrared, and the output laser wavelength can be selected from among the four and is controlled by the control device 120. The center wavelength of the laser light emitted from the infrared light source is set to, for example, a wavelength around 780 nm to enable wavelength separation from the OCT measurement light.

[0023] The first dichroic mirror 212 has the property of reflecting light in a wavelength band around 970 nm and transmitting light with wavelengths shorter than that. A lens 222, a split prism 223, a lens 224, and an anterior-segment observation CCD 225 are arranged on an anterior-segment observation optical path L3 formed by the first dichroic mirror 212. The CCD 225 captures an image of the anterior segment of the subject's eye illuminated by an anterior-segment observation light source (wavelength 970 nm), not shown. The split prism 223 is arranged on the anterior-segment observation optical path L3 so as to be conjugate with the pupil of the subject's eye E when the distance between the subject's eye E and the imaging head 110 in the Z direction (front-back direction) is appropriate. This allows the CCD 225 to capture an unsplit image of the subject's eye's pupil when the distance between the imaging head 110 in the Z direction (front-back direction) is appropriate. Furthermore, when the distance in the Z direction is inappropriate, the CCD 225 can capture an image of the pupil of the subject's eye E separated in the deflection direction of the split prism. The output signal of the CCD 225 is sent to the control device 120, and the control device 120 detects the relative position between the subject's eye E and the imaging head 110 based on the signal received from the CCD 225.

[0024] The imaging head 110 is provided with an alignment mechanism that moves the entire imaging head 110 in three dimensions (X, Y, Z) to align it with the subject's eye E. The control device 120 drives this alignment mechanism using three motors (not shown) based on relative position information between the subject's eye E and the imaging head 110 obtained from the video signal from the CCD 225, to perform the alignment operation.

[0025] The OCT optical path L1 is used to capture fundus tomographic images of the subject's eye E. The OCT optical path L1 includes an OCT scanning means 226, a focus lens 227, and a lens 228. These are shared by an OCT scanning optical system that scans the fundus with measurement light and an OCT light-receiving optical system that receives return light from the subject's eye E. The OCT scanning means 226 is used to scan the fundus with measurement light obtained from an OCT measurement light source 229. While the OCT scanning means 226 is illustrated as a single mirror in this embodiment, it is actually configured as an XY scanner consisting of two galvanometer mirrors for scanning the measurement light in two axes, X and Y. The XY scanner may be configured using any deflection means according to the desired configuration. The measurement light scanning means may also be configured as a deflection means capable of deflecting light in two dimensions using a single mirror, such as a MEMS mirror.

[0026] The focus lens 227 is used to focus the measurement light obtained from the OCT measurement light source 229 and emitted from the optical fiber 230 onto the fundus of the subject's eye, and is driven in the direction of the arrow in the drawing by a motor (not shown). By this focusing, the measurement light emitted from the end face of the optical fiber 230 forms a point image on the fundus of the subject's eye, while the returning light from there forms an image on the end face of the optical fiber 230 and is then incident on the optical fiber 230 again.

[0027] For example, an SLD (Super Luminescent Diode) is used as the OCT measurement light source 229, and the SLD emits low-coherent light having a center wavelength of 850 nm and a wavelength band of 50 nm. Note that, as the OCT measurement light source 229, a light source other than an SLD, such as an ASE (Amplified Spontaneous Emission), may be used as long as it can emit low-coherent light having a predetermined center wavelength and wavelength band.

[0028] The optical fiber 230 is connected to the OCT measurement light source 229 via an optical coupler 234 and an optical fiber 231. The optical fiber 233, which is connected to the optical coupler 234, is further connected to a spectrometer 238. Light emitted from the OCT measurement light source 229 and incident on the optical fiber 231 is split into OCT measurement light and reference light by the optical coupler 234, and the OCT measurement light is guided to the optical fiber 230. After emitting from the optical fiber 230, the OCT measurement light is guided toward the subject's eye E via optical components up to the objective lens 211 provided on the optical path of the OCT optical system (OCT optical path L1). The above optical components constitute the OCT scanning optical system. The measurement light irradiated onto the subject's eye E is reflected and scattered by the fundus of the subject's eye E, and passes through the OCT scanning optical system as returned light, reaching the optical coupler 234 again.

[0029] Meanwhile, a reference optical path is formed by an optical fiber 232, a lens 235, a dispersion compensation glass 236, and a reference mirror 237 connected to an optical coupler 234. The reference light obtained by splitting light emitted from the OCT measurement light source by the optical coupler 234 is emitted toward the reference mirror 237 via the optical fiber 232, the lens 235, and the dispersion compensation glass 236. The reference light reflected from the reference mirror 237 reaches the optical coupler 234 again via the same optical path. The reference mirror 237 is held in an adjustable position along the optical axis as indicated by the arrow in the figure by a motor and drive mechanism (not shown). This allows the optical path lengths of the OCT measurement light and the reference light, which change depending on the subject's eye E, to be adjusted within the coherence length. The adjusted reference light and the return light of the OCT measurement light are combined by the optical coupler 234 and guided to a spectrometer 238 via the optical fiber 233 as interference light.

[0030] The spectrometer 238 is composed of a lens 239, a lens 241, a diffraction grating 240, and a line sensor 242. The interference light emitted from the optical fiber 233 is converted into parallel light via the lens 239, then dispersed by the diffraction grating 240, and imaged by the lens 241 on the line sensor 242. The above optical components constitute the OCT light receiving optical system. The line sensor 242 reads the dispersed interference light, generates a light receiving signal for forming an OCT tomographic image, and transmits this to the control device 120 every 20 microseconds.

[0031] A lens 218 and a fixation lamp panel 219 are provided on a fixation lamp optical path L4 formed in the reflection direction by a beam splitter 210 made of, for example, plain glass. The fixation lamp panel 219 is, for example, a high-brightness organic EL panel, and is controlled by the control device 120 to display various patterns selected by the examiner at desired positions. A visible image of this pattern is presented to the subject's eye E, and acts as a fixation lamp to encourage the subject to fixate.

[0032] In the above-described embodiment, a Michelson interferometer is used as the interferometer, but a Mach-Zehnder interferometer may also be used. Depending on the difference in light intensity between the OCT measurement light and the reference light, it is desirable to use a Mach-Zehnder interferometer when the difference in light intensity is large, and a Michelson interferometer when the difference in light intensity is relatively small. In addition, while a spectral domain (SD) OCT device is used in this embodiment, a swept source (SS) OCT device using a wavelength-swept light source is also applicable. Furthermore, in this embodiment, a composite system of an SLO optical system and an OCT optical system is used as the imaging system, but a composite system is not necessarily required. The present invention can also be applied to an imaging head composed of only an SLO optical system or only an OCT optical system.

[0033] <Control device description> Next, the control device 120 will be described. Fig. 1(b) is a block diagram showing the control configuration of the control device 120. The control device 120 according to this embodiment includes an image generation unit 121, a storage unit 122, a control unit 123, an analysis unit 124, an acquisition unit 125, and an instruction generation unit 128.

[0034] In the present embodiment, for example, the image generation unit 121 functions as an image generation unit that generates an image using a light receiving signal, etc., which will be described later. In the present embodiment, for example, the memory unit 122 functions as a memory unit that stores scanning information, light receiving signals, and images generated by the image generation unit 121. In the present embodiment, for example, the control unit 123 functions as a control unit that controls the imaging head 110, the image generation unit 121, and the memory unit 122. In the present embodiment, for example, the analysis unit 124 functions as an analysis unit that analyzes control information from the control unit 123 and images (data) generated by the image generation unit 121 to generate necessary information. In the present embodiment, for example, the acquisition unit 125 functions as an acquisition unit that acquires necessary information from the analysis unit 124, the imaging head 110, the display unit 130, and the input unit 140. The analysis unit 124 also incorporates an information extraction unit 126 that extracts information regarding the movement of the eyeball of the subject's eye E, which will be described later, and the movement of, for example, opacified areas of the vitreous body within the eyeball. The instruction generating unit 128 generates instructions (described later) to the subject, such as encouraging the subject to blink, and the instruction generating unit may be included in the control device 120 or may be separately arranged in, for example, the imaging head 110.

[0035] Each component of the control device 120 other than the storage unit 122 can be realized by a module executed by a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The processor may be, for example, a GPU (Graphical Processing Unit) or an FPGA (Field-Programmable Gate Array). Each component of the control device 120 may be realized by a circuit that realizes a specific function, such as an ASIC. The storage unit 122 may be configured by any storage medium, such as an optical disk such as a hard disk, or a memory.

[0036] Before describing the measurement and analysis processes of an actual device according to an embodiment of the present invention, the major roles of each unit will be described. The control unit 123 controls the device by outputting control signals to each unit based on the programs constituting each component of the control device 120 stored in the storage unit 122 and control information generated by the analysis unit 124. The controlled objects include, for example, the imaging head 110, the display unit 130, and each unit within the control device 120. The control device 120 or the control unit 123 functions as a display control means for displaying an application window, etc., described below, on the display unit 130. Note that, hereinafter, the control of the acquisition unit 125, image generation unit 121, analysis unit 124, etc. within the control device 120 will not be described as being controlled by the control unit 123.

[0037] The acquisition unit 125 acquires information necessary for the operation of the device, image generation, and image analysis. Information necessary for image generation and analysis includes, for example, light-receiving signals and video signals for generating images, and information indicating the state of the optical system for converting the light-receiving signals into image data. The light-receiving signals and video signals include, for example, outputs from the SLO photodiode 220, the CCD 225, or the line sensor 242. Information indicating the state of the optical system for converting the light-receiving signals into image data includes, for example, scanning information from the SLO scanning unit 214 and the OCT scanning unit 226, which are the two scanning units of the imaging head 110. The acquisition unit 125 also functions as a GUI by cooperating with the display unit 130 to acquire operation and instruction information from the examiner, or acquires operation and instruction information from the examiner input via the input unit 140.

[0038] The image generating unit 121 generates an image (data) using the signal acquired by the acquiring unit 125, and can also generate a moving image (file) from a plurality of images generated from continuously acquired signals. Examples of images that can be generated include SLO images, tomographic images, and anterior eye images.

[0039] The storage unit 122 stores necessary information. The stored information includes, for example, SLO images, tomographic images, anterior eye images, SLO video images, tomographic video images generated by the image generation unit 121, and imaging parameters used to capture images of the subject's eye. The storage unit 122 also stores, as necessary information, computer programs and the like prepared for configuring each component of the control device 120.

[0040] The analysis unit 124 includes an information extraction unit 126. The information extraction unit 126 analyzes the image (data) generated by the image generation unit 121 to generate necessary information such as information on eye movement and information on the movement of a site with vitreous opacity. Furthermore, the necessary information also includes, for example, control information used when controlling the optical system, and additional information to be stored together with the image.

[0041] Next, the actual basic operation of each component will be described using the generation of an SLO image and an OCT image as examples. In a method for generating a frontal fundus (SLO) moving image, the control unit 123 turns on the SLO measurement light source 221 and then sends a scanning control signal, which is scanning information, to the SLO scanning means 214 to start scanning with the SLO measurement light. The returned light from the fundus of the subject's eye is converted into a light-receiving signal by the SLO photodiode 220. The image generation unit 121 samples this light-receiving signal and sequentially stores it in the memory unit 122 as pixel values ​​of pixels corresponding to each scanning position, which is scanning information, to generate a single piece of frontal fundus image data. A still image can be displayed by reading this image data and displaying it on the display unit 130. Furthermore, by repeatedly performing this series of control and continuously displaying the sequentially obtained still images in chronological order, a frontal fundus moving image can be displayed. Furthermore, while this frontal fundus moving image is being generated, the analysis unit 124 analyzes image data at different positions of the focus lens 215 to detect the focus state. The control unit 123 controls the position of the focus lens 215 based on the result of detecting the focus state, thereby realizing adjustment control of the device such as SLO autofocus adjustment.

[0042] Furthermore, by switching the wavelength range of the SLO measurement light emitted from the SLO measurement light source 221, it is possible to generate and save monochrome moving images, color still images, and color moving images, and these images can be selected as needed depending on the purpose of the image. For example, in the preview state before actual imaging, it is desirable to select monochrome moving images using only infrared wavelengths. For fundus diagnosis, it is desirable to exclusively output blue, green, and red wavelength regions in sequence to obtain image data for each color, combine these to generate a color still image, and display this.

[0043] Next, a method for generating an OCT tomographic image will be described. The control unit 123 turns on the OCT measurement light source 229 and further sends a scan control signal to the OCT scanning means 226 to start two-dimensional scanning of the fundus of the subject's eye with the OCT measurement light. The interference light obtained from the return light of the OCT measurement light from the fundus is dispersed by the spectroscope 238 and converted into a received light signal by the line sensor 242, which is acquired by the acquisition unit 125. The image generation unit 121 generates image data in the depth direction (Z direction) of the fundus of the subject's eye by, for example, Fourier transforming the received light signal acquired by the acquisition unit 125.

[0044] By associating this image data with the scanning position, which is the scanning information, image data in the depth direction at a predetermined position is obtained. Acquiring image data consisting of one-dimensional brightness or density distribution in the depth direction in this manner is called an A-scan. The OCT scanning means 226 repeatedly performs A-scans while scanning the fundus of the subject's eye E with the OCT measuring light in a predetermined main scanning direction, and acquires multiple consecutive A-scan images, thereby obtaining a single tomographic image. For example, if the control device 120 scans the OCT measuring light in the X direction, a tomographic image in the XZ plane is obtained, and if it scans in the Y direction, a tomographic image in the YZ plane is obtained. Scanning the fundus of the subject's eye E in a predetermined main scanning direction to acquire tomographic data in the scanning direction in this manner is called a B-scan, and the resulting tomographic image is called a B-scan image.

[0045] Furthermore, a 3D OCT image can be obtained by scanning in a direction perpendicular to the XZ or YZ plane of the B-scan. Repeated B-scans can also record tomographic images as tomographic video images. In either case, a video image includes a series of reproducible images taken at closely spaced times, different from a video image. Recording involves continuously capturing and storing these images, while displaying them continuously can be considered playback.

[0046] In the ophthalmic imaging device composed of the imaging head 110, the control device 120, the display unit 130, and the input unit 140 described above, a series of processes from the observation of the test eye E to imaging and further analysis will be described using the flowcharts of FIGS. 3(a) to 3(c). FIG. 3(a) shows the main processes executed during the examination. FIG. 3(b) shows the detailed processes of preview and device adjustment executed in step S303 in FIG. 3(a) during normal OCT imaging. Also, FIG. 3(c) shows the detailed processes of device adjustment in the imaging mode of the vitreous turbidity site (Vitreous Turbidity Motion) (hereinafter referred to as the VTM imaging mode), which is characteristic in this embodiment. In this embodiment, the vitreous turbidity site corresponds to a site in the vitreous of the test eye E that consists of turbidity generated in the vitreous itself, floating substances in the vitreous caused by retinal detachment, etc., and blood leaked into the eye. And it is used as a general term for sites that can be grasped as turbid sites in the vitreous when observing fundus images and tomographic images of the fundus.

[0047] <S301 Patient Selection> Prior to the examination, after the startup preparation of the imaging head 110 is completed, the examiner causes the application window 400 illustrated in FIG. 4 to be displayed on the display unit 130. Then, using the tab 450 of the patient / examination selection screen, the patient / examination selection screen is selected, and the input or selection of the patient to be examined is performed from this screen. For example, in the case of a first visit, the examiner inputs all the necessary information such as the patient name into the patient input box 451. In the case of a follow-up visit, the patient is selected from the patient candidates searched for and displayed in the patient list 452 corresponding to partial input. When the input or selection is completed, the examiner presses the OK button 455. In response to this pressing, the flow proceeds to step S302.

[0048] <S302 Mode Selection> In the ophthalmic imaging device used in this embodiment, an OCT imaging mode for capturing a normal OCT tomographic image and a VTM imaging mode are provided. In the VTM imaging mode, a moving object such as an opacification site in the vitreous humor that floats in the eye to be examined, i.e., in the vitreous body, and moves relative to the retina of the eye to be examined is imaged. In step S302, the examiner selects one of the tab 410 of the OCT examination screen and the tab 430 of the VTM examination screen of the application window 400 shown in FIG. 4 to select the examination mode to be performed next. When the examiner selects the tab 410 of the OCT examination screen, an OCT examination screen capable of displaying the acquired OCT tomographic image 411, the SLO moving image 412, and the anterior segment moving image 413 is displayed on the application window 400 as illustrated in FIG. 5.

[0049] The control device 120 causes the display unit 130 to display the selected OCT examination screen and initializes the imaging head 110. That is, the control device 120 sets the center of the fixation lamp panel 219 to be lit so that the line-of-sight direction of the eye to be examined E is parallel to the optical axis of the objective lens 211 of the imaging head 110. In addition, the control device 120 sets the focus lens 215 and the focus lens 227 to the focus lens position (OD position) corresponding to an emmetropic eye, i.e., an eye with 0 diopters.

[0050] <S303 Preview and Device Adjustment> Next, the examiner performs various adjustments of the device while achieving the preview state. Here, the process executed when the OCT imaging mode is selected will be described. Hereinafter, the details of the process performed during tomographic image capture in the normal OCT imaging mode will be described with reference to the flowchart shown in FIG. 3(b) using the application window 400 illustrated in FIG. 5.

[0051] <S311 Manual Alignment> Using a GUI such as a slide bar provided in the window of the anterior eye moving image 413, the examiner manually adjusts the XY position of the imaging head 110 so that part of the pupil is imaged by the anterior eye observation system. This adjustment may be performed by providing a separate operation button on the screen, or by specifying a point on the screen to be positioned at the center of the window with a mouse or the like. Furthermore, the imaging head 110 and the subject's eye E in the optical axis (Z) direction can also be adjusted by operating the wheel of the mouse, for example. When the position is reached where part of the pupil is imaged, the examiner presses the start button 414 to start auto-alignment.

[0052] <S312 ラフオートアライメント> When the examiner presses the start button 414, the image generation unit 121, control unit 123, analysis unit 124, and acquisition unit 125 in the control device 120 cooperate to start automatic alignment. First, the analysis unit 124 analyzes the anterior eye moving image 413 acquired by the acquisition unit 125 to determine the pupil center of the subject's eye E. The stage is driven to move the pupil center closer to the center of the anterior eye moving image, which is aligned with the optical axis of the imaging head 110, thereby adjusting the position of the imaging head 110 in the XY directions. Then, the positions of the imaging head 110 and the subject's eye E in the optical axis (Z) direction are adjusted based on, for example, the spacing between corneal reflection images of multiple anterior eye illumination light sources (not shown). The adjustments may be performed alternately and continuously, or in parallel. When the position of the imaging head 110 falls within a predetermined tolerance range, the control unit 123 transitions the flow to step S313.

[0053] <S313 ファインオートアライメント> In step S313, the control unit 123 instructs the SLO measurement light source 221 to emit only infrared light and drives the SLO scanning unit 214 to start capturing (previewing) an SLO moving image. When the rough auto-alignment adjustment is performed, the edge of the pupil of the subject's eye in the anterior-segment image becomes sharp. Furthermore, as described above, the pupil split by the split prism 223 provided on the anterior-segment observation light path L3 becomes clearly observable. The control unit 123 drives the stage to adjust the position of the imaging head 110 in the X and Y directions so that it is closer to the center of the anterior-segment moving image, and also adjusts the position of the imaging head 110 in the Z direction so that the split amount of the split pupil becomes zero. When the fine auto-alignment confirms that the positional deviation falls within a predetermined range, the control unit 123 proceeds to step S314.

[0054] <S314 オートフォーカス> In step S314, the control unit 123 starts acquiring SLO moving images and simultaneously starts scanning the fundus with the OCT measurement light. After that, once acquisition of an appropriate SLO moving image is confirmed, autofocus adjustment begins. In this embodiment, the characteristics of confocal SLO are utilized, whereby the output of the SLO photodiode 220, i.e., the light-receiving signal, is maximized when the fundus is properly focused. Then, by driving the focus lens 215 and monitoring the light-receiving signal, autofocus is performed using a so-called hill-climbing AF method, which determines the focus position. Of course, this adjustment may utilize the sharpness of the image rather than the magnitude of the light-receiving signal.

[0055] In addition, the focus of the OCT optical system may be adjusted in parallel by interlocking the focus lens 227 of the OCT optical system. The focus may be adjusted manually, and in this case, the adjustment may be made possible using a GUI such as a focus switch 415 provided on the OCT examination screen.

[0056] After the focus adjustment of the SLO optical system and the OCT optical system is completed, the information extraction unit 126 calculates the movement of the fundus of the eye to be examined from the generated SLO moving image. The control unit 123 gives a drive instruction (for correcting the scanning position) to the OCT scanning means 226 so as to correct the movement, and causes the scanning position of the OCT measurement light to follow. This is so-called fundus tracking. As a result, the movement of the eye to be examined E is canceled in the OCT moving image, and an OCT tomographic moving image in which the influence of the movement of the eye to be examined E is eliminated can be obtained. When the exemplified mountain climbing AF ends and the fundus tracking is started, the flow proceeds to step S315.

[0057] <S315 (One-time) Reference Optical Path Length Adjustment> In this state, the control device 120 receives an operation of the examiner on the reference optical path length adjustment unit 416 on the selected OCT inspection screen. Then, the reference mirror 237 is driven according to the received operation, and the reference optical path length adjustment of OCT is executed. Thus, the device adjustment in the preview state in S303 is completed, and the control unit 123 causes the flow to proceed to step S304 in FIG. 3(a).

[0058] <S304 Imaging & Confirmation> When the device adjustment in the preview state is completed and the examiner presses the capture button 417, for example, the above-described B scan is executed, and an OCT tomographic image is captured. After the imaging is completed, in order to display the captured tomographic image and confirm the tomographic image, a confirmation screen (not shown) is displayed. For example, an OK button and a re-imaging button may be provided there. On such a confirmation screen, if the imaging result is OK, the OK button is pressed to save the tomographic image, and if it is NG, the re-imaging button is pressed to discard the captured tomographic image, and the process from step S303 is repeated.

[0059] <S305 Analysis> After the OCT tomographic image is captured, when the analysis screen is selected by the tab 490, a screen for displaying analysis results such as the layer thickness in, for example, the retinal layer for the captured OCT tomographic image is displayed. Note that since the analysis of the OCT tomographic image and the displayed contents are the same as those of a general OCT device, the description here is omitted.

[0060] <VTM Imaging Mode> Next, the details of the processing performed in the VTM imaging mode, which is a feature of this embodiment, will be described. Note that most of the processing executed in the VTM imaging mode is the same as that in the above-described OCT imaging mode and follows the flow described in Fig. 3(a). In the case of the VTM imaging mode, in the mode selection of step S302, in order for the examiner to select the VTM imaging mode, the display screen is selected by the tab 430 of the VTM inspection screen. As a result, in the application window 400 illustrated in Fig. 6, the VTM inspection screen is opened. In the VTM inspection screen, compared with the OCT inspection screen illustrated in Fig. 5, for example, switches related to video display, imaging switches corresponding to eye movement, switches for selecting laser light, etc. for searching for moving bodies in the vitreous body such as vitreous opacification sites are added. Thereafter, the flow proceeds to the preview and device adjustment processing of step S303. The details of the processing performed in step S303 in the VTM imaging mode are shown, for example, in Fig. 3(c). Note that in Fig. 3(c), the processing performed from the manual alignment of S311 to the autofocus of S314 is the same as that in the case of the OCT imaging mode, so the description here will be omitted.

[0061] <S316 Turbidity Site Search> After the autofocus on the fundus site is completed in step S314, the flow proceeds to step S316. In step S316, the examiner searches for the turbidity site 432 in the vitreous body while dragging the fixation lamp mark 431 displayed on the SLO moving image 412 with a pointing device such as a mouse. <S317 Manual Focus> When the turbid part 432 is found, the examiner operates the focus adjustment switch 433 as necessary to adjust the position of the focus lens or the like so that the turbid part 432 is in focus. The Laser adjustment switch 434 provided under the focus adjustment switch 433 is a switch for adjusting the Laser power in the SLO measurement light source 221. The examiner adjusts this to set the light quantity of the SLO measurement light to a light quantity at which the turbid part 432 can be easily seen. Also, since it is usually desirable to observe in a non-dilated state, the IR radio button can be selected to select the IR laser. Of course, it is also possible to dilate the pupil of the test eye using a mydriatic agent and record in color using a visible light laser. In that case, the Color radio button should be selected. As a result, as measurement light, light in each wavelength region of blue, green, and red is exclusively output sequentially, and image data of each color can be acquired. A color still image may be generated by synthesizing the pixel values of the frames of each color obtained in this way. By performing the above operations, the preview and device adjustment processes in step S303 are completed, and then, when a predetermined time has elapsed, or by operating an adjustment end button (not shown), etc., the flow proceeds to step S304.

[0062] <S304 Imaging & Confirmation> When the examiner presses the recording start (REC) button 435, the control unit 123 causes the instruction generating unit 128 to issue a predetermined instruction to the subject. The instruction generating unit 128 instructs the subject to make a warning announcement, such as "Please blink when the chime sounds," via a speaker built into the imaging head 110. Then, for example, two seconds after the announcement ends, the instruction generating unit 128 commands the speaker to continue ringing the chime as a predetermined instruction to encourage the subject to blink, and the control unit 123 causes the acquisition unit 125 to start recording a video for, for example, eight seconds. Thereafter, the auto-alignment is temporarily stopped, and when the analysis unit 124 detects from the video signal of the image for anterior eye observation that the blinking has ended, i.e., that the eyelids have opened (the brightness of the anterior eye image has decreased and the pupil has been observed), the control unit 123 instructs the auto-alignment to resume. The image frame at this time is marked or the like, and the timing is associated with the image and stored in the storage unit 122. Recording may start from this point. The blink detection described above may of course be detection of the start of a blink, or may be performed by monitoring the SLO light reception signal.

[0063] The examiner can play back the recorded SLO video to check it. That is, when recording ends, GUI 436, which includes a play button, a playback position designation bar, and other controls for performing post-capture operations, becomes active. Pressing the play button 436a here starts playback of the SLO video. Repeated playback is possible by entering the number of repetitions in the Repeat text box. Pressing the rewind button also returns to the start of playback and allows playback or pause. Pressing the stop button 436b returns the display screen to the fundus preview. The playback position designation bar 437 indicates the playback timing during the recording of the image being played back and can also specify the recording timing for playback. The chime mark 437a and timing mark 437b above it indicate the time when the chime sounds and the time when the eyelid opens (the brightness of the anterior eye image decreases and the pupil is observed), respectively. The examiner can use these marks to determine the playback start point.

[0064] <Processing during recording and playback> When playing a moving image, in addition to playing the original image as it is, image processing can also be performed on the original image and displayed so that the examiner can more easily observe the turbidity site. In this embodiment, for example, when displaying the turbidity site, a retinal movement cancellation process that cancels the movement of the retinal pattern that is the background and shows it, a turbidity enhancement process that emphasizes the vitreous turbidity in the original image, a process that reduces the contrast of the retinal pattern that is the background, etc. can be considered. The execution or selection of these processes can be performed, for example, by selecting the display screen in the tab 470 of the VTM settings screen in the application window 400 shown in FIG. 7 and through that display screen. More specifically, it is performed according to the selection by the three check boxes in the area 471 shown in the VTM settings screen.

[0065] Next, the process performed regarding the display of the turbidity site will be described with reference to the flowchart of FIG. 8. Here, an example of video playback will be described in which an IR laser is selected as the SLO measurement light, all image processing is performed on a monochrome video imaged with near-infrared light, and repeated playback is performed once.

[0066] <S801 Reading of moving image> When the recording of the SLO moving image ends, in step S801, the control device 120 reads out the moving image to be analyzed from the storage unit 122. Taking the case where there is turbidity in the vitreous as an example, in the moving image to be analyzed, as shown in FIG. 6, the turbidity site 432 is imaged as a slightly dark shadow as a moving body that moves the inside of the examined eye relative to the retinal pattern. When the moving image is read out, the flow proceeds to step S802. Hereinafter, the vitreous turbidity site will continue to be described as a moving body corresponding to the retinal pattern.

[0067] <S802 Cancellation of retinal pattern movement> In the next step S802, a process for canceling the movement of the retinal pattern as the background is executed. Specifically, first, the analysis unit 124 calculates the amount of displacement of the retinal pattern between a series of frames due to eye movement, using one image of a frame adjacent in time as a reference frame. The amount of displacement may be obtained, for example, by performing image comparison while shifting the position of a portion of about 50% of the central part (about 70%x70% part) of the target frame with respect to the reference frame, and finding the displacement at which the image correlation becomes maximum. Then, using the obtained displacement amount, the positions of each frame are adjusted to generate a moving image in which the movement of the retinal pattern is canceled. By performing such a process, it is possible to generate a moving image in which the relative movement of the moving object with respect to the movement of the retinal pattern is extracted in a state where the influence of the movement of the retinal pattern is reduced.

[0068] In this embodiment, as described above, an eye movement that causes the movement of the retinal pattern occurs in response to an announcement to the subject, and a moving image of the fundus of the eye being examined during this movement is acquired to detect a moving object that exhibits a movement different from the movement of the retinal pattern. However, since the movement of the retinal pattern may be too large at the start of eye movement, it is advantageous to calculate the time backward from the end of the recording when the eye movement has settled for this detection of the displacement between frames. When the amount of displacement between each frame is obtained, the flow proceeds to step S803.

[0069] <S803 Generation of Retinal Pattern Image> In the next step S803, an additive average of the frame images aligned in step S802 is performed to generate an image of the retinal pattern that can be a background with less influence of the moving object. For example, in this embodiment, assuming a case where the relative movement amount of the moving object is relatively large, an additive average of each frame is performed to generate a retinal pattern that can be a background with a sufficiently reduced contrast of the moving object portion. When the image of the retinal pattern is generated, the flow proceeds to step S804.

[0070] <S804 Generation of Label Image> In the next step S804, the analysis unit 124 generates these differential images from each frame of the moving image generated in step S802 and the retinal pattern image generated in step S803. Then, by further performing binarization processing on the differential image, a label image is generated that discriminates the region where the moving object exists and the retinal pattern that is the background. Of course, in the binarization process, it is needless to say that appropriate threshold determination and noise processing such as removal of minute regions, removal of disappearing regions, and hole filling processing may be performed. After the generation of the label image, the flow proceeds to step S805.

[0071] <S805 Emphasis processing, S806 Suppression processing> In the next step S805, as the emphasis processing of the moving object to be performed, for example, the edge of this label image is detected. Then, the luminance value of the pixel corresponding to the edge portion of the moving image in which the deviation amount of the retinal pattern generated in step S802 is canceled is changed, and a contour of a color that is easily distinguishable from red, which is contained in a large amount in the retinal pattern such as blue or green, is formed to emphasize the edge portion of the moving object. Note that the method of emphasizing the moving object is not limited to this, and for example, a hue may be added to the region labeled as the moving object. Also, in step S806, processing for suppressing the display state of the background region, such as reducing the contrast of the background region and reducing the luminance of the background region, is performed. By performing such suppression processing, in the image in which the moving object is superimposed on the retinal pattern, the examiner can recognize the moving object more clearly. Note that it is preferable to perform both the processing of step S805 and the processing of step S806, but if it is easy to grasp the movement, only one of them may be executed.

[0072] Here, when the examiner presses the play button 436a, the playback of the moving image starts. However, if selections are made using the three check boxes in the area 471 shown on the VTM settings screen, the moving image after the above-described series of processes is performed before playback is displayed. These processes may be performed every time before video playback, or the results of the processes may be stored in the storage unit 122 for a predetermined number of days and reused. When the highlighting process of the moving object in step S805 and the suppression process of the retinal pattern image in step S806 are completed, the flow proceeds to step S807.

[0073] <S807 Saving the moving image> In step S807, the recorded moving image is checked in this way. If the result is OK, the OK button 438 is pressed to save the moving image as an inspection result. If the expected image has not been recorded, the recording start (REC) button is pressed again. In that case, the current recording data and its image processing results are discarded and reimaging is performed. When making this check, if it is necessary to readjust the alignment or focus, or to search again for turbidity, the Start button is pressed again. After returning the inspection procedure to step S312, readjustment and reimaging are performed. If OK is selected, the original image is saved and the next inspection becomes possible. At this time, the object to be saved is not only the original image, but also the moving image after the above-described image processing, that is, the moving image with the movement of the fundus of the eye under examination canceled, and the label image may be saved. Through the above processes, the imaging & confirmation process in step S304 in FIG. 3(a) of the VTM imaging mode is completed.

[0074] (Modification 1) In the first embodiment described above, in step S304, an example was shown in which an instruction to blink is given to the subject by voice output from the instruction generation unit 128 as a process executed when the recording start (REC) button 435 is pressed. However, the mode of instructing the subject is not limited to this. For example, it may be performed by a change in the blinking or lighting pattern of the fixation light panel 219, or both may be performed together. Furthermore, in such a case, a voice instruction such as "Please blink once when the fixation light blinks (or changes)" may be given to the subject together.

[0075] (Variation 2) In the first embodiment and the first modification described above, the operational instruction issued in step S304 when the recording start (REC) button 435 is pressed is an instruction to the subject to blink by audio output or the like, and eye movement is induced by the blink. However, the instruction to induce eye movement is not limited to blinking, and may be an instruction to guide the line of sight by moving the position of a fixation light. The ophthalmologic imaging device according to the second modification illustrated here also has a mode that uses this movement of the fixation light. In this case, the audio instruction mode in the second modification can be specified by switching between the Blink / Fixation radio buttons provided above the recording start (REC) button, for example.

[0076] By selecting this mode, eye movement can be induced by using the movement of the fixation light to guide the subject's gaze. In this case, it is recommended to provide a warning announcement to the subject in advance, such as, "When the fixation light moves, please immediately follow its movement." When the examiner presses the recording start (REC) button 435, the control device 120 moves the fixation light displayed on the fixation light panel 219 to induce eye movement. The imaging head 110 begins capturing images of the subject's eye E undergoing eye movement and capturing and storing the SLO video image displayed on the display unit 130, i.e., recording. After recording for a fixed time, e.g., 5 seconds, recording is stopped in step S304 of the flowchart shown in FIG. 3(a). During this time, anterior segment observation continues, so the start and end of eye movement may be detected from the video signal, and the start and end of recording may be controlled using the detection results.

[0077] The operation of each part and the state of the moving object at this time are shown as a timing chart in Figure 9(c). In the timing chart, from top to bottom, the audio output channel, the horizontal X coordinate value of the fixation light, the relative velocity V of the moving center of gravity position with respect to the retinal pattern, and the recording status are shown, with the horizontal axis indicating the passage of time since the recording start button was turned on. Here, as an example of how to move the fixation light presentation position, the presentation position is moved 3 mm horizontally (in the X direction) as shown in Figure 9(b) from the origin position on the optical axis, which is the initial position shown in Figure 9(a). After recording is completed, the fixation light is moved so as to slowly return from the moved fixation light presentation position to the initial presentation position.

[0078] When the recording start (RCE) button 435 is turned on, a warning announcement such as "The fixation light will move when the chime sounds. Please follow the movement of the fixation light immediately," is output from the speaker, as described above, and the chime is output one second later. When the chime ends, the fixation light moves from the presentation position shown in FIG. 9(a) to the presentation position shown in FIG. 9(b) in approximately one second. As the fixation light presentation position moves, eye movement occurs in the subject's eye following the fixation light, and the center of gravity of one of the moving objects, such as a vitreous opacity region, begins to move accordingly. If vitreous liquefaction is progressing, this movement is accompanied by a predetermined delay. Therefore, the relative position of the opacity region with respect to the retinal pattern moves in the opposite direction to the movement of the retinal pattern (i.e., the direction of eye movement), resulting in a temporary negative relative velocity.

[0079] After that, the opacified area begins to move in the direction of eye movement, following the movement of the vitreous body. However, even after the fixation light stops at the presentation position shown in Figure 9(b), the opacified area continues to move at a substantially constant speed for, for example, several seconds. Then, after 3 to 6 seconds, it slows down and comes to a near standstill. In other words, the movement of the vitreous area is induced by the movement of the background retinal pattern, but this movement is different from the movement of the retinal pattern. In this example, recording is continued for 7 seconds from the start of the movement of the opacified area, and then stopped.

[0080] Of course, this type of eye movement induction is not limited to one time, but can be repeated a predetermined number of times. In this case, for example, a return announcement such as "The fixation light will return slowly" is made, and after recording stops, the fixation light presentation position is slowly returned to its original position over about four seconds. Then, for example, a second chime is output just before the end of another three-second waiting period, and recording is started again, and the measurement cycle is repeated.

[0081] Note that the fixation light movement parameters exemplified here can be set and changed, for example, via the VTM settings screen shown in FIG. 7, in the same way as the selection of video processing. Fixation movement area 472 displays changeable parameters for fixation light movement. The parameters for fixation light movement include the movement direction (four directions, up, down, left, and right, can be selected using the direction of the arrow), the movement amount (specified as a converted distance on the retina), the number of repetitions, and the duration of repetition. Area 472 is provided with a GUI for setting these parameters. Furthermore, Announcement area 473 is provided with a GUI for specifying whether or not to issue a signal or audio announcement when a blink instruction or a fixation light movement instruction is issued.

[0082] Of course, in addition to these simple individual parameter settings for the direction of fixation light movement, the number of repetitions, and the duration of recording, the examiner may be allowed to freely change various parameters. Furthermore, sequences for performing examinations using multiple appropriate parameters may be provided so that the examiner can select from the options.

[0083] Furthermore, in this embodiment, the recording time of the SLO moving image was set to a predetermined fixed time, but it is also effective to set it to wait for the movement of the turbidity site to settle with the induced eye movement. In that case, the analysis unit 124 may simply confirm that the movement of the turbidity site has settled. This can be done, for example, by calculating a variation parameter related to the change of the SLO moving image, such as the sum of pixel value variations between consecutive frames of the SLO moving image, and the control unit 123 can monitor this variation parameter to achieve this. Of course, an upper limit time, for example, 10 seconds, may be set for the recording time, and if the movement of the turbidity site does not settle, the next step may be transitioned after 10 seconds. On the other hand, it is also possible to monitor whether the subject is correctly following the movement of the fixation light and moving the line of sight. In this case, the displacement amount obtained in step S802 in the flowchart of FIG. 8 described above, that is, the retinal pattern movement amount, may be compared with the movement of the fixation light presentation position. Furthermore, when a large deviation is observed between the two, it is also useful to interrupt the measurement once and display a warning.

[0084] <S305 Analysis> When the recording of the moving image is completed in step S807, the flow proceeds to step S305, and analysis processing regarding the moving object (turbidity site) is executed. At that time, as shown in FIG. 10, after performing the analysis processing of the stored moving image, an analysis screen that displays the state of the moving object highlighted for easy confirmation together with the analysis result is activated on the display unit 130. The analysis processing performed here will be described below using the flowchart of FIG. 11.

[0085] If the moving image and the label image that cancel the movement of the fundus of the examined eye are not saved during the previous recording, the analysis unit 124 first performs the series of processes shown in FIG. 8. Specifically, the original image is read in step S801, and the above-described image processing is performed in steps S802 to 804 to generate a label image. Of course, if they are saved, it is needless to say that the analysis may start from the analysis of the moving object labeled with the label image. The analysis unit 124 performs the following processing in subsequent steps S811 to S813.

[0086] <Identification of Moving Objects> In the final frame, if there are multiple moving objects moving inside the eye to be examined, each is assigned an ID number to identify them. Then, based on the respective moving object parameters (area, shape, color tone, etc.), the ID assigned to each moving object in adjacent frames is inherited. This ID may be displayed in the form of a number associated with the moving object, as exemplified by the moving object ID number 491 illustrated in FIG. 10 when the video is played. After the ID is assigned, the flow proceeds to step S812. Note that in the embodiment shown here, edge enhancement processing is to be performed after the ID is assigned, but it may be performed before the ID is assigned, or may be performed only on the moving objects to which the ID has been assigned. Also, this processing may not be performed.

[0087] <S812 Calculation of Relative Velocity of Moving Objects> First, in order to calculate the relative velocity, which is one of the feature amounts of each moving object, the area centroid coordinates of each moving object in each frame are calculated to determine the trajectory. Next, the velocity of each moving object is calculated from the moving distance as the relative movement amount between the frames and the frame rate. When there are multiple moving objects, it is also useful to obtain the centroid position, center position, etc. as representative points and calculate and use the group trajectory and group velocity.

[0088] Note that in this embodiment, the SLO moving image to be analyzed is a moving image in which the movement of the retinal pattern, which is the background, is canceled. For this reason, the trajectory determined here is the two-dimensional relative position with respect to the fundus of the eye to be examined, and the velocity calculated based on this is also the two-dimensional relative velocity. Hereinafter, the relative velocity calculated in this embodiment shall refer to the projection component in the direction of the induced eye movement. Note that this may be simply the projection in the indicated direction, or the direction of the total vector or average vector of the actually occurring eye movement vectors may be used. However, the analysis target is not limited to such a relative velocity, and the absolute value change of the velocity may be used as the analysis target, or the apparent velocity of the moving object may be used instead of the relative velocity with respect to the retinal pattern. Furthermore, these analysis targets may be prepared so as to be switchable, and may be switched and used as appropriate.

[0089] In any case, the index related to the speed of these moving objects can be used as an index representing the fluidity of the vitreous body. In this embodiment, as the index representing this fluidity, the speed calculated for each frame, that is, as a function of time, was used, but the average speed of the moving object between two frames obtained at specific different times may be calculated. Further, statistical quantities such as the average speed and variance over the recording time, or the speed waveform at each time may be calculated. That is, at least two frames obtained at different times are required to obtain the dynamic characteristics of the moving object. Such statistical analysis processing will be described in detail later. Furthermore, the index representing fluidity and the calculation method are not limited to this. Acceleration may be targeted, or the change in the moving direction may be quantified. Also, for the movement of the moving object caused by the eye movement due to the movement of the fixation light, the ratio of this relative speed to the movement speed of the retinal pattern may be taken.

[0090] <S813 Calculation of Other Feature Quantities of Moving Object> In this embodiment, after calculating the speed and the like of the moving object described above, other feature quantities of the moving object are further obtained. Other feature quantities include, for example, the average observed area and average observed density of each moving object over the recording time, and further, the hue and each variation amount can be included. The state of the moving object can be understood from these parameters, and when the moving object is a turbid part of the vitreous body, it can be used to preferably judge the influence it has on vision.

[0091] Using FIG. 10, an example of the analysis screen selected by the tab 490 will be further described in order to reproduce and confirm the above-described analysis results and the stored moving image. Here, the case where a moving image in which the movement of the moving object generated by the guidance of the line of sight by the fixation light shown in the second modification is analyzed will be described.

[0092] The video to be analyzed is displayed as SLO video 412, and below that display area is provided a GUI display area 492 for controlling video playback. This display screen also provides a playback control button group 493, an image processing control check box group 494, and a seek bar display group 495 for setting playback conditions.

[0093] The playback control button group 493 is a group of buttons that control playback operations such as play, stop, pause, play from the beginning, etc. The image processing control checkbox group 494 functions in the same way as the three checkboxes shown on the VTM settings screen shown in Fig. 7.

[0094] Next, the seek bar display group 495 will be described in detail. The seek bar in the seek bar display group 495 indicates the current playback position in a series of captured moving images. It moves to the right on the page as the video is played, and the playback position can be changed by operating the slider. A speed graph of the moving object being analyzed is displayed above the seek bar, with the time axis aligned with the corresponding video playback position. The dashed-dotted line on the graph is a marker indicating the current playback timing, and in combination with the graph display, it is possible to grasp the timing of the current playback. In addition, the chime mark 437a drawn on the horizontal axis of the graph indicates the time when the chime sounds, similar to the mark on the display screen displayed on the VTM test screen in Figure 6, but the time when the chime sounds coincides with the start timing of the fixation light movement. The check boxes in the upper right corner of each graph will be described later.

[0095] The moving object to be analyzed can be selected by clicking on the moving object ID number 491 displayed on or near the moving object depicted in the SLO video 412, or by using the analysis object switching pull-down menu 496. The result of this selection is displayed, for example, as shown in FIG. 10, by highlighting the outer periphery of the moving object (see moving object with moving object ID number 1), or by displaying the moving object in color. In addition, the analysis results of the movement of the selected moving object are displayed near the analysis object switching pull-down menu 496. These analysis results will be explained in order below.

[0096] The average speed graph 497 shows the average speed change of the speed graphs for which the checkboxes in the upper right corner of the graph on the seek bar are checked. In other words, the average speed graph 497 represents the typical movement of the moving object being analyzed. The horizontal axis of the average speed graph 497, which is the time axis, can be overlapped with multiple speed graphs so that the timing of the chime output, i.e., the start of the fixation light movement, coincides. Furthermore, the multiple speed graphs may be aligned so that the rise of the observed speed coincides, and may be switchable with the previously overlapped graphs.

[0097] The following two periods, a floating period and a tail period, are defined during the speed observation period, and the analysis result display 498 extracts and displays, for example, the following as other information related to the moving object: (1) Floating period: A period during which the moving object continues to move at a substantially constant speed after the eye movement starts. In this embodiment, this is defined as the period from when the observed speed increases to 90% of the maximum speed to when it subsequently decreases to 80%. (2) Tail period: A period after the floating period in which the speed of the moving object gradually decreases. In this embodiment, this is defined as the period until the speed becomes 10% or less of the maximum speed. (3) Movement delay time (Dlay): Defined as the delay time from the bell mark (the start time of the fixation light movement) to the start time of the floating period. (4) Moving object speed parameters: They are defined as the average speed VAve., maximum speed VMax, deceleration ratio RDecel. in the tail period, etc. of the moving object during the floating period selected as the analysis target. (5) Moving object characteristic parameters: They are defined as the average observed area SAve., average observed density DAve., etc. Also, as measurement conditions, for example, the fixation light movement parameter 480 may be displayed. As the movement parameters, for example, the same items as those in the Fixation movement area 471 within the VTM settings screen can be displayed.

[0098] <S814 Playback of video, etc.> Using the GUI prepared as described above, the examiner can switch the analysis target and check the analysis results. In addition, by freely playing the recorded video, the movement of the moving object can be observed in detail. As described above, here, after saving the video captured in the VTM imaging mode, an example of the process of analyzing the moving object in the saved image and displaying the result has been described. However, in this embodiment, this analysis and display of the analysis results can also be performed on the moving images recorded and stored in past examinations. In such a case, the examination and selection of the moving image can be performed, for example, by the tab 450 shown in FIG. 4, and the examination / moving image 454 to be targeted can be selected from the examination / moving image list 453 provided on the left side of the screen that appears after the patient is specified on the patient / examination selection screen. Note that since such a process is a process generally performed in a general ophthalmic examination device, detailed description here is omitted.

[0099] Note that in this embodiment, after correcting the movement of the retinal pattern as the background, a difference image between each of a series of frames and the background image is created to extract the moving object (background difference method). However, the extraction method is not limited to the background difference method. For example, it may be based on the optical flow calculation result by block matching or the like, or the result by the inter-frame difference method for detecting a moving object from the logical product of the differences of three or more frame images may be used.

[0100] In the following, an example in which a moving object is extracted using an optical flow result obtained by a block matching method will be described as Modification 3. Also, an example in which a moving object is extracted using an inter-frame difference method will be described as Modification 4.

[0101] (Variation 3) In Variation 3, a block matching method (also known as a region-based method), which is one method for calculating optical flow, is adopted to detect moving objects using template matching. Specifically, one of two temporally adjacent images is used as the target image and the other as the reference image, and the position to which a pixel at a predetermined position in the reference image has moved in the target image is determined. More specifically, for example, a small square region centered on a predetermined pixel in the reference image, i.e., a partial image, is used as the template block, and a search is made for the position at which the image matches best within an area twice the length and width of the partial image, i.e., four times the area, centered on the predetermined pixel position in the reference image. Then, a vector quantity with the predetermined pixel position in the reference image as the starting point and the position in the target image at which the match is best is used as the optical flow for each pixel.

[0102] To check the degree of match between the two images, you can look at the sum of absolute differences or the correlation between the images, and to shorten the calculation time, you can stop the calculation when the value obtained by adding the residuals exceeds a certain threshold. Of course, the method for calculating optical flow is not limited to the block matching method; for example, a sequential residual detection method, which has lower calculation costs, can also be used.

[0103] The target moving image for which the optical flow is to be calculated can be, for example, the moving image read out in step 801 in the flow of Fig. 8 or Fig. 11. That is, according to this modification, it is also possible to obtain a labeled image in step S804 by using a moving image in which the movement of the retinal pattern has not been canceled as the target image without performing the processes of the next steps S802 and S803.

[0104] Moving objects, such as vitreous opacities, that are the subject of analysis in this modification move differently from the background retinal pattern. When the moving object does not occupy a significant proportion of the entire screen, the majority of the optical flows of each pixel calculated for adjacent image pairs have a substantially uniform direction and magnitude, corresponding to the movement of the retinal pattern caused by eye movement. Therefore, moving objects can be identified by recognizing pixels in which flows with a direction or magnitude separable from this are observed as pixels that constitute moving objects. Of course, this separation is not observed during periods when the target moving object moves substantially similarly to the retinal pattern, so moving objects cannot be separated at all times. However, by identifying pixels in which this separation can be confirmed as moving objects for a predetermined period of time during the observation period, a labeled image can be generated that distinguishes the area where the moving object exists from the background retinal pattern. In this modification, the subsequent processing is similar to that described in Example 1, and therefore further description will be omitted.

[0105] Alternatively, the target image may be a moving image in which the movement of the retinal pattern obtained in step S802 has been canceled, and a labeled image may be generated from this. In this case, the optical flow of the pixels that make up the retinal pattern is nearly zero, so the search for the position with the highest image match converges within a narrower range. This not only shortens the search time, but also makes it possible to easily separate and identify moving objects using a simpler binarization process based on the magnitude of the flow, instead of the separation process performed by analyzing the direction and magnitude of the optical flow of each pixel described above. In this case, the amount of calculation can also be significantly reduced by manually or otherwise specifying the range in which the target moving object exists in advance.

[0106] (Variation 4) In Modification 3, an example of calculating optical flow to detect a moving object was shown, but as described below in Modification 4, it is also useful to use the frame difference method using three adjacent images. The processing performed in this modification is basically the same as the processing shown in Figure 8 or Figure 11. That is, after reading out a moving image in step S801 and generating a moving image in which the movement of the retinal pattern has been canceled in step S802, the following processing is executed in the next step 804 of generating a labeled image.

[0107] Here, the frame image from which a moving object is extracted and identified is designated as N, and the images before and after it are designated as N-1 and N+1. In this case, differential images ND1 and ND2 between image N-1 and image N, and image N and image N+1, respectively, are created, and threshold processing is performed on these to obtain binary images. Here, a logical AND operation is performed on the two binary images, and the common area between them is extracted, thereby enabling the moving object in image N to be extracted or identified. Then, based on the results, a labeled image is generated in which the area where the moving object exists and the retinal pattern, which is the background, are identified. Note that in this modified example, the subsequent processing is the same as that described in the first embodiment, and therefore further description will be omitted.

[0108] In this modification, the selection of the previous and next images may not only be limited to adjacent frame images, but may also utilize frame images separated by a predetermined time interval depending on the moving speed of the moving object. Furthermore, it is possible to combine these images appropriately to further improve the accuracy of the moving object extraction. Furthermore, the threshold used for binarization may reflect the variance of brightness values ​​in multiple frame images over a predetermined period of time. By adopting such a method, the system is less susceptible to background changes due to lighting conditions resulting from the alignment of the optical head, and detection performance can be expected to improve.

[0109] As described above, the ophthalmic imaging apparatus according to this embodiment includes an imaging head 110, an image generating means (image generating unit 121), a memory means (memory unit 122), a means for detecting the movement of the subject's eye (control unit 123), and an extraction means (information extracting unit 126). The imaging head includes a measurement light source (221, 229), a scanning optical system (214, 226), and a light receiving optical system (220, 238). The measurement light source emits SLO measurement light (or light for obtaining OCT measurement light). The scanning optical system scans the interior of the subject's eye with the measurement light in accordance with predetermined scanning information. The light receiving optical system receives return light of the measurement light from the subject's eye and generates a light receiving signal. The image generating means can generate an image by, for example, identifying a position in the subject's eye from which a light receiving signal is acquired using the scanning information and converting the light receiving signal corresponding to the identified position into luminance information or the like. The storage means stores multiple images of the same type of subject's eye, which are generated by the image generation means. The stored images are images obtained under predetermined movements, such as movements of the subject's eye in response to voice instructions or movements exceeding a predetermined threshold when the subject's eye is detected (movements that allow the detection of unique movements of vitreous opacities, etc.). Examples of images of the same type include frontal fundus images and fundus tomographic images. The means for detecting the subject's eye movement detects the movement of the subject's eye by comparing multiple stored images obtained from the same subject's eye. Moving objects, such as vitreous opacities, exist within the subject's eye, particularly in the vitreous body. These moving objects move in response to the movement of the subject's eye, but because they are suspended in the vitreous body, they move differently from the detected movement of the subject's eye. The extraction means extracts information about the moving objects using at least two of the images stored in the storage means.

[0110] The above-described ophthalmic imaging apparatus may further include an instruction generating means (instruction generating unit 128) that issues an instruction to the subject to induce the subject's eye to move. In this case, the instruction generating means may include an audio output means, such as a speaker or chime, that generates an audio instruction to the subject to induce the subject's eye to blink. Although this audio output means is provided in the imaging head 110 in this embodiment, it may also be located elsewhere than the imaging head, for example, in an examination room, with the control unit 123 instructing it via communication or the like. As described above, the predetermined movement of the subject's eye is detected based on an image. However, if the predetermined movement is initiated by, for example, an audio instruction from the instruction generating means, the image following the instruction may be used for moving object detection. Furthermore, the movement of the subject's eye may be detected not only based on an image but also based on a received light signal. For example, the movement of the subject's eye may be detected based on the peak position of the received light signal or the movement of a boundary position that is expected to form an edge when the image is generated.

[0111] The imaging head may further include a fixation lamp display means (fixation lamp panel 219) that displays a fixation lamp at a predetermined position to guide the fixation of the subject's eye. In this case, the instruction generating means may issue an instruction to the fixation lamp display means to move the display position of the fixation lamp in order to induce movement of the subject's eye. Furthermore, the instruction generating means may repeat the above-mentioned various instructions a predetermined number of times. The above-mentioned means for detecting the movement of the subject's eye may detect the movement of the subject's eye based on a light receiving signal.

[0112] The above-described ophthalmologic imaging device may further include a blink detection unit that detects blinking of the subject's eye as one of the movements of the subject's eye. For example, the blink detection unit may be a unit (anterior-segment observation optical system) that captures an image of the anterior segment of the subject's eye, which is included in the imaging head 110. In this case, the start of the movement of the subject's eye can be detected based on an image acquired by the imaging unit. Furthermore, the storage unit may store the image generated by the image generation unit and the detected movement of the subject's eye in association with each other.

[0113] In addition, the above-described ophthalmic imaging device may further include display control means (control unit 123) for controlling the connected or integrated display means (display unit 130). The display control means can further repeatedly display a moving image generated using a plurality of images based on the received light signals acquired continuously in time on the display means.

[0114] The above-described embodiments can also be understood as a control method for controlling an ophthalmic imaging device. In this control method, a step of generating an image (image generation process in step S304) is included, which uses predetermined scanning information for scanning the inside of the subject eye with measurement light and a received light signal obtained by receiving the return light of the measurement light from the subject eye. Then, a plurality of continuously acquired and generated images are stored as a moving image in the storage unit 122 (process of storing the generated image in step S304). The stored moving image is read out in step S801, and the movement of the subject eye is detected based on the image in step S802. After detecting the movement of the subject eye, in step S804, information regarding a moving object such as a vitreous opacity site is extracted from the read-out moving image and the like.

[0115] (Second Embodiment) In the first embodiment, the moving image targeted in the VTM imaging mode was set as the SLO moving image captured by the SLO optical system of FIG. 2. Here, the ophthalmic imaging device used in the first embodiment also has an OCT optical system. Therefore, an OCT moving image can also be captured in parallel in the VTM imaging mode. In this embodiment, the object for extracting a moving object in the VTM imaging mode is the OCT moving image. Note that since the ophthalmic imaging device used in this embodiment is the same as the ophthalmic imaging device described in the first embodiment, the description here is omitted.

[0116] <OCT Imaging in the VTM Imaging Mode> The processes performed in the imaging and analysis of OCT moving images in the VTM imaging mode largely coincide with the processes performed in the shooting and analysis of SLO moving images described in the first embodiment. Therefore, here, in the processes executed in the flowchart of Fig. 3(a), steps S303 and S304 where different processes from the first embodiment are performed will be further described below with reference to Figs. 12 and 13. Note that Fig. 12 is a flowchart of the processes executed regarding preview and device adjustment performed in the second embodiment, but the processes executed up to step S317 are the same as the processes up to step S317 executed in Fig. 3(c) of the first embodiment. For this reason, the description here regarding the processes up to step S317 will be omitted. After the execution of manual focus at step S317, the examiner further proceeds with the preparation for OCT imaging using the VTM inspection screen according to this embodiment shown in Fig. 13(a).

[0117] <S318 Setting of OCT scanning parameters> In the VTM inspection screen according to this embodiment, in addition to each display in the VTM inspection screen (for SLO moving images) according to the first embodiment illustrated in Fig. 6, switches etc. for corresponding to OCT moving images are added. Fig. 13(a) shows the VTM inspection screen selected by tab 430 as an example where such a switch is added. Note that the focus adjustment switch 433, the Laser adjustment switch 434 below it, etc. are prepared on the VTM inspection screen in the same manner as in the first embodiment. The examiner operates the focus adjustment switch 433 to perform focus adjustment on the turbidity site 432.

[0118] After the adjustment is completed, in order to enable the option for performing OCT imaging in parallel, the OCT checkbox 441 is checked. The dropdown menu prepared beside the OCT checkbox 441 is for selecting the number of B-scan scans, and in this embodiment, 1, 3, 5, and 7 are presented in advance. The examiner selects an appropriate number of B-scans from these. Hereinafter, the case where 3 B-scans are selected will be described as an example.

[0119] When the OCT check box 441 is checked, a scanning line mark 442 indicating the OCT scanning site is displayed on the SLO moving image 412, and the scanning of the fundus by the OCT measurement light is started. In this embodiment, the initial values of the scanning information related to the OCT video imaging are, for example, three scanning lines, a scanning line interval of 0.5 mm, and the center of the central scanning line is located at the center of the SLO moving image 412. Then, the scanning of the OCT measurement light is performed in the direction of the eye movement induced by the instruction for inducing the eye movement.

[0120] Also, in this embodiment, the examiner can also adjust the scanning conditions by operating this scanning line mark 442. For example, the scanning position can be adjusted by dragging near the center of the scanning line mark 442, the scanning width can be adjusted by dragging the end points, and the scanning angle can be adjusted by operating an angle adjustment marker (not shown) that appears when the mouse is over the scanning line mark 442. By adjusting the scanning conditions in this way, it is possible to set the scanning conditions so that the scanning line mark 442 covers the locus of the turbidity site 432 of the vitreous body that is assumed. Thereafter, the examiner switches the display switching radio button 443 provided beside the anterior segment moving image 413 from Anterior to OCT to check the OCT tomographic image.

[0121] <S315 Reference light path automatic adjustment> FIG. 13(b) shows a VTM examination screen switched from the display of the anterior segment moving image 413 to the display of the OCT tomographic moving image 444 by switching the display switching radio button 443. The tomographic image displayed on the OCT tomographic moving image 444 is a tomographic moving image of the scanning line designated by the number in the spin box provided below the display switching radio button 443. Also, the turbidity site 432 of the vitreous body displayed on the SLO image is displayed as a tomographic image 445 of the vitreous turbidity site on the OCT tomographic moving image 444.

[0122] In this embodiment, the scanning line on which the tomographic image is displayed in the scanning line mark 442 may be displayed discriminably, for example, as a thicker line than other scanning line marks 442 or with a different color. While observing the OCT tomographic moving image 444 here, the examiner operates the reference optical path length adjustment unit 416 to adjust the reference optical path length of the OCT. By performing such an operation, the device adjustment in the preview state, which is the process performed in step S303, is completed. After the device adjustment is completed, the flow proceeds to step S304.

[0123] <S304 Imaging & Confirmation> The process executed when the recording start (REC) button 435 is pressed is similar to the process executed in the above-described first embodiment. When the examiner presses the recording start (REC) button 435, the instruction generation unit 128 gives an instruction to induce eye movement to the subject. As an example of the instruction, for example, a preview announcement of "Please blink when the chime rings" is output, and after the chime prompting blinking, for example, an 8-second video recording is started. At this time, the OCT measurement light sequentially scans the scanning lines displayed as the scanning line mark 442, and the tomographic image is also recorded as a moving image in parallel with the SLO layer image.

[0124] After the recording is completed, the recorded SLO moving image and OCT moving image are confirmed in the same manner as in the case of the first embodiment by pressing the playback button 436a to play back the recording. Also, in this embodiment, the playback of the OCT video and the SLO video is synchronized. During playback, repeated playback, rewinding, pausing, etc., which were possible in the first embodiment, are also executable in the same manner in this embodiment.

[0125] <Processing during Video Playback> In the first embodiment, when reproducing a moving image, in addition to reproducing the original image as is, it is also possible to perform image processing on the original image to allow the examiner to more easily observe the opacified area. The same applies to the reproduction of OCT moving images in this embodiment. Specifically, in addition to reproducing the original image as is, it is also possible to perform the above-mentioned retinal movement cancellation processing, opacity enhancement processing, and contrast reduction processing to reproduce the image. Retinal movement cancellation processing is a processing that cancels the movement of the background retinal pattern, and opacity enhancement processing is a processing that emphasizes the vitreous opacity in the original image and displays it. Furthermore, contrast reduction processing is a processing that reduces the contrast of the background retinal pattern.

[0126] In the first embodiment, when displaying an SLO video sequence, the movement of the background retinal pattern is canceled in step S802 in FIG. 8 . In this embodiment, similar processing can be performed on captured tomographic images in the OCT tomographic video sequence 444 to cancel the movement of the tomographic images. Specifically, the analysis unit 124 first calculates the amount of positional shift of the tomographic images between a series of frames caused by eye movement, using one image from a temporally adjacent frame as a reference frame. The amount of positional shift can be determined, for example, by comparing the central 50% portion (approximately 70% x 70%) of the retinal tomographic section of the target frame with the reference frame while shifting their positions, and then determining the amount of positional shift that maximizes image correlation. The position of each frame is then adjusted using the determined amount of shift to generate a video sequence in which the movement of the retinal pattern has been canceled. By performing this processing, a video sequence can be generated in which the relative movement of the moving object with respect to the movement of the tomographic image is extracted while reducing the influence of the movement of the tomographic image.

[0127] As with the first embodiment, it is advantageous to perform calculations retroactively from the end of recording, when eye movement has settled, to detect positional deviations between frames. The processes performed in steps S803 to S806 in the first embodiment are also performed in the same manner for the tomographic video images of this embodiment. Specifically, an arithmetic average of each frame image is performed to generate a tomographic image that is less affected by the moving object and can serve as the background, and each frame of the generated video and the tomographic image are used to generate a labeled image that distinguishes between the area where the moving object exists and the retinal pattern that is the background. Similar processes can then be performed for highlighting the moving object and reducing the contrast of the background area. The selection method for playing back the video is also the same as in the first embodiment.

[0128] <Check and save video images> Using the above functions, the recorded video is checked, and if the results are satisfactory, the OK button 438 is pressed to save the video as the inspection result. If the expected image is not recorded, the start recording (REC) button can be pressed again, as in the first embodiment. However, in this embodiment, the number of scan lines is limited in order to perform OCT imaging as a video. For this reason, adjusting the OCT imaging conditions to properly record the target moving object with this limited number of scan lines is somewhat difficult, and it is undeniable that adjusting the measurement range in particular takes some time.

[0129] (Variation 1) In the above description, the display switch radio button 443 is used to switch from the display of the anterior segment moving image 413 to the OCT tomographic moving image 444. However, even when Anterior is selected with the display switch radio button 443 and the anterior segment moving image 413 is displayed, the display may be automatically switched to the OCT tomographic moving image 444 when an operation is better performed while viewing the OCT tomographic image. Examples of such an operation include an operation on the scanning line mark 442 or the reference optical path length adjustment unit 416, or when a moving image is being played back. Furthermore, the display may be automatically switched to the OCT tomographic moving image 444 when appropriate alignment is performed by auto-alignment and the amount of positional deviation is within an allowable range. Furthermore, it is useful to be able to switch the display positions of the SLO moving image and the OCT moving image during playback.

[0130] (Variation 2) The ophthalmic imaging device used in this embodiment has an analysis function for performing movement analysis of moving objects, such as vitreous opacification areas recorded in a video that has been recorded and confirmed, that move differently from the tomographic image of the subject's eye observed as the background. However, it would be useful in eye examinations if simple observation of moving objects in the vitreous body were possible without performing such analysis of vitreous opacification areas, etc. In the following Modification 2, an example focusing on observation of such moving objects will be described.

[0131] In the first and second embodiments, post-processing is performed on the recorded video to cancel the movement of the retinal pattern or tomographic image and further to extract the moving object. In contrast, in this modified example, the process of canceling the movement of the retinal pattern or tomographic image is performed based on the tracking process performed during imaging.

[0132] In the first embodiment, fundus tracking is executed in step S314 such as in FIG. 3(b). In step S314, the information extraction unit 126 processes the SLO moving image generated by the image generation unit 121 to calculate the movement of the fundus of the subject eye. Then, according to the calculation result, the control unit 123 gives a drive instruction to the OCT scanning means 226 so that the OCT measurement light follows the movement of the subject eye E. In this modification, the control unit 123 controls the SLO scanning means 214 so that not only the OCT measurement light but also the SLO measurement light follows the movement of the subject eye. By applying fundus tracking to the SLO scanning system in this way, the obtained SLO image is acquired as an image in which the retinal pattern serving as the background does not move. Therefore, an image in a state where the movement of the retinal pattern as the background is canceled can be obtained over time without performing post-processing after imaging, and the relative movement of the moving body can be observed.

[0133] Also, for example, a preliminary measurement may be performed once before this measurement, and a retinal pattern image that can serve as a background may be generated in advance based on the data. In this case, the retinal pattern image and the real-time image captured in this imaging may be calculated and aligned in real time, and the aligned image may be displayed. According to this method, it is also possible to perform processing for emphasizing the moving body and suppressing the background area in accordance with the extraction of the moving body. When performing such real-time calculation of images, since there is a risk that the calculation load will increase, it is desirable for the control unit to be equipped with a GPU or the like.

[0134] As described above, in this modification as well, the examiner can repeatedly reproduce and confirm the behavior of the moving body such as the vitreous opacity site recorded. Further, this can be highlighted and the behavior of the vitreous opacity site can be observed independently of the eye movement.

[0135] <Analysis of S305> Here, the analysis of the moving object and the process of displaying the analysis results in the second embodiment will be described. The results of the analysis process of the stored moving image are displayed on the analysis screen in the same manner as in the first embodiment, but the analysis process is executed for each B-scan video in each OCT scanning line. FIGS. 14(a), 14(b), and 14(c) show three tomographic images obtained by scanning different scanning lines arranged at arbitrary intervals with measurement light. Also, the moving objects 445a, 445b, and 445c shown in each tomographic image indicate the moving objects identified within their respective tomographic moving images.

[0136] When the width of each scanning line is below a certain width, the identified moving object can be determined as, for example, a single moving object with a contour on three slices as shown in FIG. 14(d). Therefore, the shape can be defined by a polygon model with the intersections of the contour and the grid at a predetermined pitch of the B-scan cross-section as contour points. Also, a wireframe model can be formed by, for example, spline interpolation, etc., to estimate the approximate shape of the three-dimensional moving object. Further, the characteristic quantities of the moving object may be calculated using the estimated shape. However, when the number of slices is small, these processes are not very useful, and it is more important to grasp the positional relationship between the moving object and the retina. Also, when analyzing the three-dimensional speed of the moving object, it is important to treat these as a single moving object rather than as separate moving objects. Regarding the other processes executed during the analysis, since they are the same as the processes described in the first embodiment, the description here will be omitted.

[0137] <S814 Playback of video, etc.> Also in the second embodiment, as in the first embodiment, the examiner can switch the moving object to be analyzed and confirm the analysis results for each moving object. Also, in the same manner as in the first embodiment, it is possible to freely play the recorded video to observe the movement of the moving object in detail.

[0138] FIG. 15(a) shows an example of a method for displaying an OCT video on the analysis screen of this modified example. In an examination in which OCT imaging is performed in parallel, a button 501 for opening an OCT video window is displayed to the left of the SLO video 412 on the analysis screen. When the examiner clicks this button, a pop-up window 502 for displaying the OCT video opens, as shown in FIG. 15(b), and a scan line mark 442 indicating the scanning position where OCT imaging was performed is displayed on the SLO video 412. The playback operation of the OCT video is always synchronized with the playback operation of the SLO video, and playback conditions, etc. can be controlled using a playback control button group 493, an image processing control checkbox group 494, a seek bar display group 495, etc.

[0139] In the OCT video images displayed in the pop-up window 502, for example, an ID is assigned to the identified moving object 503, and the moving object may be color-coded for each B-scan video in the same color as the scan line mark 442 and displayed superimposed. Each B-scan video may also be displayed independently (see FIG. 14(e)). Furthermore, the pop-up window 502 may be movable to any position in the application window 400, and the display magnification may be variable. Furthermore, the pop-up window 502 may be made full screen or may be closed using a button provided above.

[0140] As described above, in the ophthalmologic imaging apparatus according to this embodiment, a moving object can also be extracted using a tomographic image of the subject's eye acquired by the OCT optical system. In this case, in the imaging head 110, in order to generate a tomographic image, the light receiving optical system generates interference light between the reference light corresponding to the measurement light and the return light, and the image generating means (image generating unit 121) generates a tomographic image of the subject's eye using the interference light. In this case, the scanning optical system (OCT scanning means 226) in the OCT optical system may scan the measurement light in a direction (scanning direction in this embodiment) determined based on the direction of movement of the subject's eye detected from the generated image.

[0141] As described above, the ophthalmologic imaging apparatus according to the second embodiment enables simple three-dimensional observation and analysis in addition to two-dimensional observation and analysis of moving objects, thereby making it possible to obtain more detailed information for determining the degree of vitreous liquefaction, the behavior of moving objects such as vitreous opacity, and the impact on visual function.

[0142] (Other Examples) The present invention can also be realized by providing a program that realizes one or more functions of the above-described embodiments and modifications to a system or device via a network or a storage medium, and having the computer of the system or device read and execute the program. The computer has one or more processors or circuits, and may include multiple separate computers or a network of multiple separate processors or circuits to read and execute computer-executable instructions.

[0143] The processor or circuitry may include a central processing unit (CPU), a microprocessing unit (MPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), or a field programmable gateway (FPGA). The processor or circuitry may also include a digital signal processor (DSP), a data flow processor (DFP), or a neural processing unit (NPU).

[0144] Although the present invention has been described above with reference to the examples and modifications, the present invention is not limited to the above examples and modifications. The present invention also includes inventions that have been modified within the scope of the present invention and inventions equivalent to the present invention. Furthermore, the above examples and modifications can be combined as appropriate within the scope of the present invention. [Explanation of symbols]

[0145] 110: imaging head, 120: control device, 130: display device, 140: input device, 121: image generation unit, 122: storage unit, 123: control unit, 124: analysis unit, 125: acquisition unit, 126: information extraction unit

Claims

1. an imaging head including a measurement light source that emits measurement light, a scanning optical system that scans the interior of the subject's eye with the measurement light in accordance with predetermined scanning information, and a light receiving optical system that receives return light of the measurement light from the subject's eye and generates a light receiving signal; an image generating means for generating an image using the scanning information and the light receiving signal; a storage means for storing a plurality of images of the same type relating to the same subject's eye under a predetermined movement, the images being generated; means for detecting the predetermined movement based on the stored images; an analysis means for identifying, using at least two of the stored images, an area where an opacity site exists in the vitreous body of the subject's eye, and which exhibits a movement induced by the predetermined movement and different from the detected predetermined movement, and for calculating information about the movement of the identified opacity site using at least two of the stored images; An ophthalmic imaging device comprising:

2. 2. The ophthalmologic imaging apparatus according to claim 1, further comprising an instruction issuing unit that issues an instruction to the subject to induce the predetermined movement in the subject's eye.

3. an imaging head including a measurement light source that emits measurement light, a scanning optical system that scans the interior of the subject's eye with the measurement light in accordance with predetermined scanning information, and a light receiving optical system that receives return light of the measurement light from the subject's eye and generates a light receiving signal; an image generating means for generating an image using the scanning information and the light receiving signal; a storage means for storing the generated images of the same type of images of the subject's eye after an instruction generating means has issued an instruction to the subject to induce a predetermined movement in the subject's eye; a calculation means for identifying, using at least two of the stored images, an area where an opacity site exists within the vitreous body of the subject's eye, and where the opacity site exhibits a movement different from the predetermined movement when induced by the predetermined movement, and for calculating information about the movement of the identified opacity site using at least two of the stored images; An ophthalmic imaging device comprising:

4. 4. The ophthalmologic imaging apparatus according to claim 2, wherein the instruction generating means comprises a voice output means for generating a voice instruction for inducing a blink of the subject's eye to be examined.

5. the imaging head further includes a fixation lamp presenting means for presenting a fixation lamp at a predetermined position to guide the fixation of the subject's eye, 4. The ophthalmologic imaging apparatus according to claim 2, wherein the instruction generating means generates an instruction to the fixation lamp presenting means to move the presenting position of the fixation lamp in order to induce a movement of the subject's eye.

6. 6. The ophthalmologic imaging apparatus according to claim 2, wherein the instruction generating means repeats the instruction a predetermined number of times.

7. The ophthalmologic imaging apparatus according to claim 1 , further comprising a blink detection unit for detecting a blink of the subject's eye.

8. the imaging head further includes a means for imaging an anterior segment of the subject's eye, The ophthalmologic imaging apparatus according to claim 7 , wherein the blink detection means includes the imaging means.

9. the imaging head further includes a means for imaging an anterior segment of the subject's eye, The ophthalmologic imaging apparatus according to claim 1 , wherein the start of movement of the subject's eye is detected based on an image acquired by the imaging means.

10. The ophthalmologic imaging apparatus according to claim 1 , wherein the storage unit stores the generated image and the detected movement of the subject's eye in association with each other.

11. The ophthalmologic imaging device according to any one of claims 1 to 10, further comprising a display control means for controlling the display means to repeatedly display a moving image generated using a plurality of images based on received light signals acquired successively over time.

12. The ophthalmologic imaging apparatus according to claim 1 , wherein the same type of image is a front image of the fundus of the subject's eye or a tomographic image of the fundus.

13. the light receiving optical system generates interference light between the reference light corresponding to the measurement light and the return light; The ophthalmologic imaging apparatus according to claim 1 , wherein the image generating means generates a tomographic image of the subject's eye using the interference light.

14. The ophthalmologic imaging apparatus according to claim 13 , wherein the scanning optical system scans the measurement light in a direction determined based on a direction of movement of the subject's eye.

15. The ophthalmological imaging device of claim 11, wherein the display control means controls the display means to repeatedly display the moving image obtained using at least two of the stored images, in which the influence of movement of the retinal pattern of the test eye is reduced.

16. A control method for an ophthalmologic imaging device including an imaging head having a measurement light source that emits measurement light, a scanning optical system that scans the interior of a subject's eye with the measurement light in accordance with predetermined scanning information, and a light receiving optical system that receives return light of the measurement light from the subject's eye and generates a light receiving signal, comprising: generating an image using the scanning information and the received light signal; storing a plurality of images of the same type for the same subject's eye under a predetermined motion; detecting the predetermined movement based on the stored images; a step of identifying, using at least two of the stored images, an area where an opacity site exists in the vitreous body of the subject's eye, the opacity site exhibiting a movement induced by the predetermined movement and different from the detected predetermined movement; and calculating information about the movement of the identified opacity site using at least two of the stored images; A method for controlling an ophthalmic imaging apparatus, comprising:

17. A control method for an ophthalmologic imaging device including an imaging head having a measurement light source that emits measurement light, a scanning optical system that scans the interior of a subject's eye with the measurement light in accordance with predetermined scanning information, and a light receiving optical system that receives return light of the measurement light from the subject's eye and generates a light receiving signal, comprising: generating an image using the scanning information and the received light signal; a step of storing a plurality of images of the same type regarding the subject's eye, which are the generated images, after an instruction generating means has issued an instruction to the subject to induce a predetermined movement in the subject's eye; a step of identifying, using at least two of the stored images, an area where an opacity site exists in the vitreous body of the subject's eye, the opacity site exhibiting a movement different from the predetermined movement induced by the predetermined movement, and calculating information about the movement of the opacity site using at least two of the stored images; A method for controlling an ophthalmic imaging apparatus, comprising:

18. A program that, when executed by a computer, causes the computer to execute each step of the method for controlling an ophthalmologic imaging apparatus according to claim 16 or 17.

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