Fundus imaging apparatus and fundus imaging method

Abstract

To provide a fundus photographing apparatus and a fundus photographing program capable of satisfactorily photographing a panoramic image.SOLUTION: A driving unit configured to adjust a positional relationship between an eye to be examined and an imaging unit including an imaging optical system and a fixation optical system; And control means for capturing a fundus front image, wherein the fixation optical system has a first fixation target for guiding a line of sight of the subject's eye to a position on or near an imaging optical axis of the imaging optical system and a second fixation target for guiding the line of sight of the subject's eye to a position around the first fixation target, and the control means is capable of selectively executing a standard imaging mode for imaging one position on the fundus and a panoramic imaging mode for sequentially imaging a plurality of positions on the fundus, and in the panoramic imaging mode, positions corresponding to the first fixation target are guided so as to be arranged in order.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a fundus imaging device and a fundus imaging program. [Background technology]

[0002] Some fundus imaging devices for capturing frontal fundus images of a subject's eye are equipped with a panoramic imaging function to obtain a wider range of fundus images. This type of device can capture multiple frontal fundus images of the subject's eye at different fixation positions and synthesize the multiple frontal fundus images to obtain a panoramic image. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-254907 Summary of the Invention [Problem to be solved by the invention]

[0004] However, it is not always possible to capture a good panoramic image of the subject's eye. In particular, when considering automatic imaging of each image, there is room for improvement in the imaging order and alignment.

[0005] The present disclosure has been made based on at least one of the problems of the above-mentioned conventional techniques, and has as its technical object to provide a fundus photography device and a fundus photography program that can take good panoramic images. [Means for solving the problem]

[0006] A fundus photographing device according to a first aspect of the present disclosure includes a photographing optical system that photographs a front image of the fundus of an eye to be examined, a fixation optical system that can switch the presentation position of a fixation target to change the line of sight of the eye to be examined, a driving means that adjusts the positional relationship between the eye to be examined and a photographing means that includes the photographing optical system and the fixation optical system, and a control means that controls the driving means to move the photographing means relative to the eye to be examined and controls the photographing optical system to photograph the front image of the fundus of the eye to be examined, wherein the fixation optical system is The imaging device has a first fixation target for guiding the line of sight of the subject's eye to a position on or near the imaging optical axis of the imaging optical system, and a second fixation target for guiding the line of sight of the subject's eye to a position away from the imaging optical axis and around the first fixation target, and the control means is capable of selectively executing a standard imaging mode in which one position on the fundus is photographed, and a panoramic imaging mode in which multiple positions on the fundus are photographed in sequence, and is characterized in that it guides the position corresponding to the first fixation target to be photographed in the panoramic imaging mode.

[0007] A fundus photography program according to a second aspect of the present disclosure is executed by a fundus photography device including: a photography optical system that photographs a front image of the fundus of a subject's eye; a fixation optical system that is capable of switching the presentation position of a fixation target to change the line of sight of the subject's eye, the fixation optical system having a first fixation target for guiding the line of sight of the subject's eye on or near the photography optical axis of the photography optical system, and a second fixation target for guiding the line of sight of the subject's eye to a position away from the photography optical axis and surrounding the first fixation target; and a driving means for adjusting the positional relationship between the subject's eye and a photography means including the photography optical system and the fixation optical system. The fundus photography program is executed by a processor of the fundus photography device to cause the fundus photography device to execute a control step of controlling the driving means to move the photography means relative to the subject's eye and controlling the photography optical system to photograph a front image of the fundus of the subject's eye, wherein the control step can selectively execute a standard photography mode in which one position on the fundus is photographed and a panoramic photography mode in which multiple positions on the fundus are photographed in sequence, and is characterized in that the control step guides the position corresponding to the first fixation target to be photographed in the panoramic photography mode. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an external view of a fundus imaging device. [Figure 2] FIG. 2 is a diagram showing an optical system of the fundus imaging apparatus. [Figure 3] FIG. 2 is a diagram showing the arrangement of fixation lights of a fixation target unit. [Figure 4] 10 is an example of an examination setting screen in a standard imaging mode. [Figure 5] 10 is an example of an examination selection screen in a standard imaging mode. [Figure 6] 10 is an example of a shooting screen in standard shooting mode. [Figure 7] 10 is an example of a confirmation screen for the standard shooting mode. [Figure 8] 10 is an example of a first setting screen in a panoramic photography mode. [Figure 9]10 is an example of a second setting screen in a panoramic photography mode. [Figure 10] 10 is an example of a second setting screen showing the order in which fixation lights are turned on. [Figure 11] 10 is an example of a photographing screen when a first fixation light is presented in a panoramic photographing mode. [Figure 12] 10 is an example of a confirmation screen when a first fixation light is presented in panoramic photography mode. [Figure 13] 10 is an example of a photographing screen when a second fixation light is presented in panoramic photographing mode. [Figure 14] 10 is an example of a confirmation screen when a second fixation light is presented in panoramic photography mode. [Figure 15] 1 is an example of a panoramic image. [Figure 16] FIG. 10 is a diagram showing alignment positions in a standard imaging mode. [Figure 17] FIG. 10 is a diagram showing alignment positions in a panoramic photography mode. DETAILED DESCRIPTION OF THE INVENTION

[0009] [overview] An embodiment of a fundus imaging device according to the present disclosure will be described. Each embodiment may be applied to part or all of the other embodiments. For example, the items grouped in < > below may be used independently or in conjunction with each other.

[0010] The fundus imaging device according to this embodiment includes at least an imaging optical system, a fixation optical system, a driving unit, and a control unit. The fundus imaging device may further include a projection optical system, an anterior segment observation optical system, and a setting unit.

[0011] <Photographing optical system> The photographing optical system photographs a front image of the fundus of the subject's eye. For example, the photographing optical system may be an OCT optical system having an OCT configuration. The OCT optical system may photograph a front image of the fundus by utilizing interference between measurement light and reference light irradiated onto the subject's eye. Furthermore, for example, the photographing optical system may be an SLO optical system having an SLO configuration. The SLO optical system may irradiate illumination light onto the fundus of the subject's eye and photograph a front image of the fundus based on return light of the illumination light from the fundus. Furthermore, for example, the photographing optical system may be a fundus camera optical system having a fundus camera configuration. The fundus camera optical system forms an illumination area and a light-receiving area for the photographing light in the pupil of the subject's eye. Furthermore, the photographing optical system photographs a front image of the fundus of the subject's eye by projecting and receiving photographing light through the illumination area and the light-receiving area. The photographing optical system may also serve as a fundus observation optical system for acquiring a fundus observation image.

[0012] In addition, in the photographing optical system (fundus camera optical system), the configuration for setting pupil division is referred to as a pupil division unit for convenience. The pupil division unit is composed of, for example, one or more optical elements arranged at a position conjugate with the pupil of the subject's eye. Examples of optical elements include various components such as an aperture, a light shield, a light source, and a prism.

[0013] <Fixation optical system> The fixation optical system projects a fixation target onto the subject's eye to change the line of sight of the subject's eye. The fixation optical system may be capable of switching the position at which the fixation target is presented relative to the subject's eye. For example, the fixation optical system may selectively project a fixation target onto the subject's eye, thereby positioning the fixation target at a presentation position corresponding to one fundus position photographed in a standard imaging mode (described later) and multiple fundus positions photographed in a panoramic imaging mode (described later).

[0014] The fixation optical system may include a visible light source (fixation light). For example, if the fixation optical system includes one fixation light, the fixation target presentation position can be switched by moving the fixation light. Also, for example, if the fixation optical system includes multiple fixation lights, the fixation target presentation position can be switched by controlling the lighting of the fixation lights. The fixation optical system may include a display means for displaying the fixation target. In this case, the fixation target presentation position can be switched by changing the display position of the fixation target.

[0015] The fixation optical system may have a first fixation target and multiple second fixation targets. The first fixation target is used to guide the gaze of the subject's eye to the imaging optical axis or its vicinity. For example, the first fixation target can prevent or minimize the fixation of the subject's eye, allowing the fundus to be positioned at the center of the fundus during imaging. The second fixation target is used to guide the gaze of the subject's eye to a position away from the imaging optical axis and peripheral to the first fixation target. For example, the second fixation target can significantly minimize the fixation of the subject's eye, allowing the fundus to be positioned at the periphery of the fundus during imaging.

[0016] In this embodiment, the first fixation target and the multiple second fixation targets may be formed by multiple light sources that are different distances from the imaging optical axis. In this case, the first fixation target corresponds to a light source that is arranged on or near the optical axis of the fixation optical system. The second fixation target corresponds to a light source that is arranged farther from the optical axis of the fixation optical system than the first fixation target.

[0017] <Projection optical system> The projection optical system projects a projection light beam onto the cornea of ​​the subject's eye. The number of light beams, the light beam state (e.g., convergent light beam, divergent light beam, etc.), and the projection position of the projection light beams projected onto the cornea may be determined as appropriate depending on the purpose. Furthermore, the projection optical system allows a corneal reflection image of the projection light beam to be projected onto the anterior eye segment observation image as a target image, which can be used for alignment (positioning).

[0018] For example, a pair of projected light beams at infinity and a projected light beam at a finite distance forming a ring pattern may be projected onto different positions on the cornea. In this case, it is easy to ensure the detection range of the target images by these projected light beams in the left-right, up-down, and front-back directions, enabling accurate alignment guidance based on the target images.

[0019] <Anterior segment observation optical system> The anterior-segment observation optical system acquires an anterior-segment observation image of the subject's eye, the anterior-segment observation image including a target image formed by a projected light beam. The anterior-segment observation optical system may share at least a part of the photographing optical system, or may be provided separately from the photographing optical system. The anterior-segment observation image is used for alignment between the subject's eye and the photographing means. The anterior-segment observation image may be an image of the anterior segment photographed from the front, or may be an image photographed from an oblique direction.

[0020] <Drive means> The driving means adjusts the positional relationship between the subject's eye and the imaging means including the imaging optical system and the fixation optical system. For example, the driving means may move the imaging means three-dimensionally (left and right, up and down, and front and back) relative to the subject's eye. For example, the driving means may have one or more actuators for moving the imaging means three-dimensionally. For example, the imaging means may include a projection optical system, an anterior eye observation optical system, etc. in addition to the imaging optical system and the fixation optical system.

[0021] <Control means> The control means controls the driving means to move the imaging means relative to the subject's eye and controls the imaging optical system to capture a frontal fundus image of the subject's eye. The control means can selectively execute two imaging modes: a standard imaging mode and a panoramic imaging mode. In this embodiment, in the standard imaging mode, one position on the fundus is imaged. In this case, a frontal fundus image is captured with a first fixation target and one of multiple second fixation targets presented. In the panoramic imaging mode, multiple positions on the fundus are imaged in sequence. The imaging position on the fundus is changed by changing which of the first fixation target and multiple second fixation targets is presented to the subject's eye. Note that each time the imaging position on the fundus is changed, the control unit may control the driving means to adjust the alignment.

[0022] In this embodiment, the control means guides the examiner to always capture a position corresponding to the first fixation target in the panoramic imaging mode. The "guidance" may be implemented as an operation of the device during imaging. For example, when capturing images of multiple positions in sequence in the panoramic imaging mode, a restriction may be imposed on skipping (interrupting) the capture of the position corresponding to the first fixation target. As a specific example, skipping may be prohibited. Furthermore, an operation input for skipping may be accepted, and when the operation input is accepted, an additional operation input for skipping may be requested along with a confirmation message. The "guidance" may also be implemented as a restriction or guidance on the examiner's operation input when presetting the imaging positions and imaging order in panoramic imaging to positions and orders desired by the examiner. For example, when setting the imaging order in the panoramic imaging mode, guidance may be provided by outputting a warning message if the imaging of the position corresponding to the first fixation target is fixed or if the imaging of the position is not included in the imaging order.

[0023] <Panorama composition> In this embodiment, the control means may generate a panoramic image by collaging multiple frontal fundus images captured in panoramic photography mode. The panoramic collage may be performed by an image processing device separate from the fundus imaging device. In this case, the multiple frontal fundus images captured in panoramic photography mode may be transferred to a storage means accessible from the processor of the image processing device. The external storage means may be, for example, a server connected to a network, a memory of a separate device, or the like.

[0024] As described above, in this embodiment, the control means guides the camera so that the position corresponding to the first fixation target is always captured in the panoramic imaging mode. This facilitates good alignment between multiple frontal fundus images obtained by sequentially capturing multiple positions on the fundus in the panoramic imaging mode. In other words, if a frontal fundus image is captured at a position corresponding to the first fixation target, it becomes possible to reliably align each image based on that image. As a result, it becomes easier to properly synthesize a panoramic fundus image from multiple frontal fundus images.

[0025] <Shooting order in panorama shooting mode> In this embodiment, the order of photographing in the panoramic photography mode is fixed such that the photographing of the position corresponding to the first fixation target is first, and the position corresponding to the second fixation target may be second or later. For example, the cornea of ​​the subject's eye exhibits a significantly more varied and non-uniform curvature the further away from the corneal center. Therefore, when the subject tilts his or her gaze, the reliability of alignment using a corneal reflex, as in this embodiment, decreases. Furthermore, for example, when the subject tilts his or her gaze more significantly (i.e., the farther away from the imaging optical axis the fixation target is presented), the image becomes a scleral reflex rather than a corneal reflex, reducing the reliability of alignment. However, by presenting the first fixation target first, alignment in the first photographing can be performed more smoothly and accurately. In other words, panoramic photography starts smoothly.

[0026] In this case, in this embodiment, information obtained from the alignment for the first photograph (photographing a position corresponding to the first fixation target) may be used for alignment in the second and subsequent photographs of positions corresponding to the second fixation target. This improves the accuracy of alignment in each photograph in the panoramic photographing mode. In detail, the control unit acquires position information (first position information) regarding the position of the target image formed by the projected light beam of the projection optical system while presenting the first fixation target to the subject's eye. The control unit acquires corneal shape information regarding the corneal shape based on the first position information. For example, the first position information may be detected based on an anterior eye observation image. Furthermore, for example, at least one piece of information such as corneal curvature and corneal radius of curvature may be acquired as the corneal shape information based on the first position information. Next, when photographing a position corresponding to the second fixation target, the control unit controls the alignment of the photographing unit in the working distance direction based on the corneal shape information. For example, if the target image is projected from the projection optical system in the form of a ring pattern, the ring pattern may be approximated as an ellipse, and the position of the imaging means may be adjusted in the working distance direction so that the diameter of the ellipse (longer diameter, shorter diameter, or the average of the two) is a target value. The target value is set in advance based on corneal shape information. In this embodiment, corneal shape information that differs for each subject's eye can be obtained as highly reliable information. Furthermore, accurate alignment is possible even if the subject's fixation varies widely.

[0027] <Setting and changing the shooting order> The photographing position and photographing order in the panoramic photographing mode may be changeable. For example, when the photographing order is preset, the control means accepts a setting operation of the photographing order via a GUI for setting the order. In this embodiment, the control means may guide the user via the GUI for setting the order so that photographing of the position corresponding to the first fixation target is always included in the photographing order in the panoramic photographing mode. The GUI is displayed on the display means.

[0028] For example, the GUI for setting the order may have a first selection screen and a second selection screen as follows. The first selection screen has a first selection button arranged thereon for selecting a first fixation target. The second selection screen is a screen different from the first selection screen and has a second button arranged thereon for selecting a second fixation target. The first selection screen may be displayed first, and the display may transition to the second selection screen on the condition that the first fixation target is selected. In other words, the display may not transition to the second selection screen unless the first fixation target is selected via the first selection screen. The control means may complete setting of the predetermined shooting order when it receives an operation signal from both the first selection button and the second selection button. This requires the examiner to select the first fixation target, thereby maintaining a certain level of reliability and shooting accuracy in panoramic photography.

[0029] The control means may cause the display means to display the first selection screen and the second selection screen side by side. In this case, the setting of the shooting order may be completed when both the input of an operation signal from the first selection button and the input of an operation signal from the second selection button are received. Alternatively, the control means may cause the display means to display both the first selection screen and the second selection screen one at a time. For example, in this case, the first selection screen may be displayed first, and the second selection screen may be displayed based on the input of an operation signal from the first selection button, and the setting of the shooting order may be completed based on the input of an operation signal from the second selection button. Similarly, the second selection screen may be displayed first, and the first selection screen may be displayed based on the input of an operation signal from the second selection button, and the setting of the shooting order may be completed based on the input of an operation signal from the first selection button.

[0030] The present disclosure is not limited to the devices described in the present embodiment. For example, terminal control software (programs) that perform the functions of the above embodiments may be supplied to a device or system via a network or various storage media, and a control device (e.g., a CPU) of the device or system may read and execute the program.

[0031] [Example] Next, an example of the fundus imaging apparatus according to the embodiment will be described.

[0032] The fundus photographing device 1 photographs a front image of the fundus Er of the subject's eye E. As the front image, at least a color fundus image is photographed.

[0033] FIG. 1 is an external view of a fundus imaging device 1. In this embodiment, the fundus imaging device 1 has an imaging unit 3, a base 7, a drive unit 8, a face support unit 9, a control unit 100, and a touch panel display 120 (hereinafter referred to as the touch panel 120). In the following description, for convenience, the unit in which the imaging unit 3 is installed will be referred to as the device main body. In this embodiment, the base 7, drive unit 8, face support unit 9, control unit 100, and touch panel 120 are part of the device main body. However, the control unit 100 and touch panel 120 may be units separate from the device main body. The base 7, drive unit 8, and face support unit 9 can be omitted from the device main body as appropriate.

[0034] In this embodiment, the drive unit 8 moves the imaging unit 3 on the drive unit 8 in each of the X, Y and Z directions relative to the subject's eye E. The drive unit 8 has an actuator for moving the imaging unit 3 in each movable direction, and is driven based on a control signal from the control unit 100. The face support unit 9 supports the subject's face. The face support unit 9 is fixed to the base 7.

[0035] The photographing unit 3 is an examination unit in this embodiment. The photographing unit 3 mainly includes the optical system shown in FIG. 2. As shown in FIG. 2, the fundus photographing device 1 includes a front photographing optical system 10, an anterior eye observation optical system 40, and a fixation target projection optical system 80. In this embodiment, as shown in FIG. 2, these three optical systems share an objective optical system and are coaxially aligned by a beam splitter / combiner (e.g., a half mirror and a dichroic mirror). The fundus photographing device 1 also includes a target projection optical system 70.

[0036] <Frontal shooting optical system> The front photographing optical system 10 will be described with reference to Fig. 2. In Fig. 2, the pupil conjugate position conjugate with the pupil of the subject's eye is indicated by a "△" on the optical axis, and the fundus conjugate position is indicated by an "X" on the optical axis.

[0037] The front imaging optical system includes an illumination optical system 10a and a light-receiving optical system 10b. The illumination optical system 10a includes a light source unit 11, a lens 13, a slit-shaped member 15a, lenses 17a and 17b, a mirror 18, a perforated mirror 20, and an objective lens 22. The light-receiving optical system 10b includes an objective lens 22, a perforated mirror 20, lenses 25a and 25b, a slit-shaped member 15b, and an image sensor 28.

[0038] The light source unit 11 has multiple types of light sources with different wavelength bands. For example, the light source unit 11 has visible light sources 11a and 11b and infrared light sources 11c and 11d. As such, the light source unit 11 of this embodiment is provided with two light sources for each wavelength. The two light sources of the same wavelength are arranged apart from the optical axis L on the pupil conjugate plane. The two light sources are arranged along the X direction, which is the scanning direction in FIG. 2, and are arranged axially symmetrically with respect to the optical axis L. As shown in FIG. 2, the outer periphery of the two light sources may be rectangular in shape, with the direction intersecting the scanning direction being longer than the scanning direction.

[0039] Light from the two light sources passes through the lens 13 and is irradiated onto the slit-shaped member 15a. In this embodiment, the slit-shaped member 15a has a light-transmitting portion (aperture) formed in an elongated shape along the Y direction. This causes the illumination light to be formed in a slit shape on the fundus conjugate plane (the slit-shaped illuminated area on the fundus Er is shown as symbol B).

[0040] The slit-shaped member 15a is displaced by a driving unit (not shown) so that the light-transmitting portion crosses the optical axis L in the X direction. This realizes scanning of the illumination light in this embodiment. Note that in this embodiment, scanning is also performed by the slit-shaped member 15b on the light-receiving system side. In this embodiment, the slit-shaped members on the light-emitting side and the light-receiving side are driven in conjunction with each other by a single driving unit (actuator). This forms a scanning unit including the slit-shaped members 15a and 15b. The scanning unit may be, for example, an optical chopper. For details of an optical system employing an optical chopper, see, for example, Japanese Patent Application Laid-Open No. 2019-118721 filed by the present applicant.

[0041] In the illumination optical system 10a, the images of the light sources are relayed by the optical system from the lens 13 to the objective lens 22 and formed on the pupil conjugate plane. That is, pupil images by the two light sources are formed at positions separated in the scanning direction on the pupil conjugate plane. In this way, in this embodiment, two illumination regions P1 and P2 on the pupil conjugate plane are formed as images of the two light sources.

[0042] The slit-shaped light that has passed through the slit-shaped member 15a is relayed by the optical system from the lens 17a to the objective lens 22, and forms an image on the fundus Er. This forms a slit-shaped illumination light on the fundus Er. The illumination light is reflected on the fundus Er and extracted through the pupil Ep.

[0043] The perforated mirror 20 is an optical path coupling section that couples the optical paths of the irradiation optical system 10a and the light receiving optical system 10b. The perforated mirror 20 reflects the illumination light from the light source unit 11 toward the subject's eye E, and transmits a portion of the fundus reflected light from the subject's eye E that passes through the aperture toward the image sensor 28. Various beam splitters other than the perforated mirror 20 can be used.

[0044] Because the aperture of the perforated mirror 20 is conjugate with the pupil of the subject's eye, the fundus reflected light used for imaging is limited to a portion that passes through the image of the perforated mirror aperture (pupil image) on the pupil of the subject's eye. Therefore, the image of the aperture on the pupil of the subject's eye becomes the light-receiving area J in this embodiment. The light-receiving area J is formed between two illumination areas P1 and P2 (images of the two light sources). Furthermore, as a result of appropriately setting the imaging magnification of each image, the diameter of the aperture, and the arrangement distance between the two light sources, the light-receiving area J and the two illumination areas P1 and P2 are formed so as not to overlap each other on the pupil.

[0045] The fundus reflected light that passes through the objective lens 22 and the aperture of the perforated mirror 20 forms an image of a slit-shaped region of the fundus Er at a fundus conjugate position via lenses 25a and 25b. At this time, harmful light is removed by arranging the light-transmitting portion of the slit-shaped member 15b at the position of image formation.

[0046] The image sensor 28 is positioned at a conjugate position with the fundus. In this embodiment, a relay optical system 27 is provided between the slit-shaped member 15b and the image sensor 28, thereby establishing a conjugate relationship between the slit-shaped member 15b and the image sensor 28. As a result, both removal of harmful light and image formation are performed effectively. Alternatively, the relay optical system 27 between the image sensor 28 and the slit-shaped member 15b may be omitted, and the two may be positioned closely together. In this embodiment, a device with a two-dimensional light-receiving surface is used as the image sensor 28. For example, it may be a CMOS, a two-dimensional CCD, or the like. An image of the slit-shaped region of the fundus Er formed by the light-transmitting portion of the slit-shaped member 15b is projected onto the image sensor 28. The image sensor 28 is sensitive to both infrared light and visible light.

[0047] In this embodiment, as the slit-shaped illumination light is scanned on the fundus Er, images (slit-shaped images) of the scanning positions on the fundus Er are sequentially projected for each scanning line of the image sensor 28. In this way, the entire image of the scanning range is projected on the image sensor 28 in a time-division manner. As a result, a front image (two-dimensional reflection image) of the fundus is captured as the entire image of the scanning range.

[0048] In this embodiment, the scanning unit in the light receiving optical system 10b is a device that mechanically scans the slit, but this is not necessarily limited to this. For example, the scanning unit on the light receiving optical system 10b side may be a device that electronically scans the slit. As an example, if the image sensor 28 is a CMOS, slit scanning may be achieved by the rolling shutter function of the CMOS. In this case, by displacing the area to be exposed on the imaging surface in synchronization with the scanning unit in the irradiation optical system 10a, it is possible to efficiently capture images while eliminating harmful light. Also, a liquid crystal shutter or the like may be used as a scanning unit that electronically scans the slit.

[0049] The front photographing optical system 10 has a diopter correction unit. In this embodiment, diopter correction units (diopter correction optical systems 17 and 25) are provided in the independent optical paths of the irradiating optical system 10a and the receiving optical system 10b, respectively. However, the diopter correction units may be provided in the common optical path of the irradiating optical system 10a and the receiving optical system 10b.

[0050] The front imaging optical system 10 may further include an index projection optical system 50. The index projection optical system 50 projects two split indices onto the fundus Er as focus indices. The split indices are used for focus detection.

[0051] <Anterior segment observation optical system> The anterior-segment observation optical system 40 will be described with reference to FIG. 2. The anterior-segment observation optical system 40 captures an image of the anterior segment of the subject's eye E and acquires it as an anterior-segment observation image. The anterior-segment observation optical system 40 illuminates the anterior segment with infrared light and captures a front image of the anterior segment. The anterior-segment observation optical system includes a light source 41, a half mirror 45, an imaging element 47, a dichroic mirror 43, an objective lens 22, and the like. For example, the light source 41 is an infrared light source and illuminates the subject's eye E. For example, the imaging element 47 is a two-dimensional imaging element and is arranged at a position optically conjugate with the pupil Ep. The dichroic mirror 43 and the objective lens 22 are shared with the front imaging optical system 10.

[0052] <Fixation target projection optical system> 2 and 3, the fixation target projection optical system 80 will be described. The fixation target projection optical system 80 projects (presents) a fixation target to the subject's eye E. When the subject looks at the fixation target, movement of the line of sight is suppressed. The fixation target projection optical system 80 may include, for example, a fixation target unit 81 and a relay lens 83, and may share the optical path from the dichroic mirror 85 to the objective lens 22 with the front imaging optical system 10. The fixation target unit 81 emits visible light.

[0053] As shown in Fig. 3, the fixation target unit 81 is provided with, for example, a plurality of fixation lamps that emit visible light. For example, LEDs are used as the fixation lamps. Each fixation lamp forms a light-emitting dot (visible light source) that emits visible light. Here, visible light refers to light that is visible to the subject's eye, and includes light in a wavelength band that is visible to the subject's eye in the infrared range, such as light with a wavelength of 800 nm to 850 nm.

[0054] The fixation light of the fixation target unit 81 includes a first fixation light 150 for guiding the line of sight of the subject's eye to a position on or near the optical axis L1 of the front imaging optical system 10. The fixation light of the fixation target unit 81 also includes a second fixation light 151 for guiding the line of sight of the subject's eye to a position away from the optical axis L1 and around the first fixation light 150. The first fixation light 150 and the second fixation light 151 are used when capturing a frontal fundus image.

[0055] The first fixation light 150 (the fixation light within the dotted line frame in the figure) includes a fixation light 82a and fixation lights 82b to 82e. The fixation light 82a is arranged on the optical axis L. The fixation lights 82b to 82e are arranged around the fixation light 82a and close to the optical axis L. For example, by presenting the fixation light 82a and the fixation lights 82b to 82e to the subject's eye, a front image of the center of the fundus can be acquired. More specifically, by using the fixation light 82a, a front image in which the macula is positioned at the center of the image can be acquired. By using the fixation light 82b or 82d, a front image in which the midpoint between the macula and the optic disc is positioned at the center can be acquired. By using the fixation light 82c or 82e, a front image in which the optic disc is positioned at the center of the image can be acquired.

[0056] The second fixation light 151 has fixation lights 82f to 82u. The fixation lights 82f to 82u are arranged around the fixation lights 82b to 82e and at positions far from the optical axis L. For example, by presenting the fixation lights 82f to 82u to the subject's eye, a front image of the peripheral part of the fundus can be acquired.

[0057] <Indicator projection optical system> The index projection optical system 70 will be described with reference to FIG. 2. The index projection optical system 70 projects an alignment index onto the cornea of ​​the subject's eye E. The index projection optical system 70 includes a first index projection optical system 73 and a second index projection optical system 71. The first index projection optical system 73 projects parallel light (infinitely distant light). The second index projection optical system 71 projects divergent light (finitely distant light). The first index projection optical system 73 is disposed symmetrically in the directions of 0 degrees and 180 degrees with respect to the optical axis L, and the second index projection optical system 71 is disposed concentrically in the directions of 45 degrees, 90 degrees, 135 degrees, 225 degrees, 270 degrees, and 315 degrees with respect to the optical axis L. In this embodiment, the alignment index is projected in a ring pattern from the index projection optical system 70.

[0058] In this embodiment, when the fixation lamp 82a is presented to the subject's eye E, the alignment states in the X and Y directions are detected based on the center position of the target image formed by the second target projecting optical system 71. The alignment state in the Z direction is detected based on the image height ratio between the target image at infinity and the target image at a finite distance.

[0059] When fixation lights 82b to 82e are presented to the eye E, the alignment state in the X direction is detected based on the position of the pupil of the eye. The alignment states in the Y and Z directions are detected based on the target image, as in the case where the fixation light 82a is presented. Furthermore, when fixation lights 82f to 82u are presented to the eye E, the alignment states in the X and Y directions are detected based on the position of the pupil. The alignment state in the Z direction is detected based on the corneal shape of the eye (details will be described later).

[0060] <Control unit> The control unit 100 is a processing device (processor) that controls each unit and performs calculations. The control unit 100 includes a CPU, RAM, ROM, etc. For convenience, the control unit 100 is also assumed to perform image processing of various images obtained by the fundus imaging device 1. In other words, the control unit 100 also functions as an image processing unit.

[0061] The control unit 100 is electrically connected to each part, such as the drive unit 8, the frontal imaging optical system 10, the anterior eye observation optical system 40, the fixation target projection optical system 80, the index projection optical system 70, the memory unit 101, the touch panel 120, etc.

[0062] The storage unit 101 may be a non-transitory storage medium that can retain its contents even when the power supply is cut off. For example, the storage unit 101 stores various control programs, fixed data, etc. Also, for example, the storage unit 101 stores images captured by the fundus imaging device 1. The captured images may be transferred to an external storage device (for example, a storage device connected to the control unit 100 via a LAN or WAN).

[0063] <Touch panel display> The touch panel 120 serves as both a monitor and an operation input unit in the fundus imaging device 1. Various images are displayed on the touch panel 120. A graphical user interface (GUI) is also displayed on the touch panel 120, and operations on UI elements (widgets) performed by the examiner are accepted. Various touch operations are input via the touch panel 120.

[0064] <Operation description> The flow of operations of the fundus photographing apparatus 1 in this embodiment will be described with reference to FIGS.

[0065] First, the examiner newly registers or retrieves the subject's identification information (ID, name, age, etc.). For example, the identification information is input by reading a barcode containing the subject's identification information with a barcode reader connected to the device, or by directly entering the information via a keyboard. When photographing a subject whose identification information has already been registered, the identification information may be retrieved by displaying a list of subjects and selecting the appropriate one from the list.

[0066] Next, the examiner determines the imaging mode to be applied to capturing a front image of the fundus of the subject's eye and performs various settings in advance. In this embodiment, it is possible to select between a standard imaging mode in which one front image of the fundus of the subject's eye is captured and a panoramic imaging mode in which multiple front images of the fundus of the subject's eye are captured. In this embodiment, it is also possible to set at least one of the fixation position of the subject's eye and the imaging order for each imaging mode. The control unit 100 accepts selection operations for the subject's eye to be imaged, the imaging mode, the fixation position and imaging order of the subject's eye, etc., and starts imaging based on these. This will be described in detail below.

[0067] <Standard shooting mode> First, the standard photography mode of this embodiment will be described. The standard photography mode is a mode in which the line of sight of the subject's eye E is fixed at one arbitrary position and photography is performed only once. More specifically, this mode is a mode in which one fixation light is presented to the subject's eye E and a predetermined fundus position is photographed only once. Therefore, the examiner sets in advance which of the first fixation light 150 and the second fixation light 151 will be turned on.

[0068] The examiner operates the touch panel 120 and selects an operation button (not shown) to call up a fixation light setting screen for the standard imaging mode. Based on the input of an operation signal from the operation button (not shown), the control unit 100 causes the touch panel 120 to display the examination setting screen 210 shown in FIG.

[0069] 4 is an example of the examination setting screen 210. The examination setting screen 210 displays a first fixation light selection button 86 (selection button 86a and selection buttons 86b to 86e) corresponding to the first fixation light 150 (fixation light 82a and fixation lights 82b to 82e). The examination setting screen 210 also displays a second fixation light selection button 88 (selection buttons 88f to 88u) corresponding to the second fixation light 151 (fixation lights 82f to 82u). For example, the first fixation light selection button 86 and the second fixation light selection button 88 are arranged so as to match (substantially match) the positional relationship from the optical axis L of the first fixation light 150 and the second fixation light 151.

[0070] The examiner selects one fixation light selection button corresponding to the fixation light that the examiner wants the examinee's eye to fixate from among the first fixation light selection buttons 86 and the second fixation light selection buttons 88 displayed on the examination setting screen 210. In this embodiment, an example is given in which the examiner selects the selection button 86a of the first fixation light selection button 86. The control unit 100 changes the display color of the selection button 86a based on an operation signal input by the examiner's selection of the selection button 86a. Of course, the shape and size of the selection button 86a may also be changed. This allows the examiner to easily confirm the selection button that the examiner has selected.

[0071] The examiner checks the change in the display color of the selection button on the examination setting screen 210 and operates the decision button 205. The control unit 100 reflects the setting of the fixation light based on the operation signal input by the examiner's operation of the decision button 205. That is, the control unit 100 reflects the setting so that the fixation light 82a is turned on in the standard imaging mode.

[0072] Next, the examiner operates the touch panel 120 to select the eye to be photographed and the application of the standard photographing mode by pressing an operation button (not shown). Based on the input of an operation signal from the operation button (not shown), the control unit 100 causes the touch panel 120 to display an examination selection screen 220 shown in FIG.

[0073] FIG. 5 is an example of the examination selection screen 220. The examination selection screen 220 displays an eye selection button 201, an imaging mode selection button 203, and a start button 206. The eye selection button 201 is a button for selecting the right eye, the left eye, or both eyes as the eye to be imaged. In the example of FIG. 5, three buttons are provided, one corresponding to the right eye, one corresponding to the left eye, and one corresponding to both eyes. The imaging mode selection button 203 is a button for selecting an imaging mode. In the example of FIG. 5, at least a standard imaging button 203a and a panoramic imaging button 203b are arranged as the imaging mode selection button 203.

[0074] The examiner selects the right eye, left eye, or both eyes as the eye to be photographed using the eye selection button 201. The examiner also selects the button corresponding to the photographing mode to be applied to the eye to be examined using the photographing mode selection button 203. In this embodiment, an example is given in which the examiner selects the left eye as the eye to be photographed and selects the standard photographing button 203a. When the examiner presses the start button 206, the control unit 100 starts photographing the left eye in the standard photographing mode based on the operation signal input from the start button 206.

[0075] The control unit 100 controls the fixation target projection optical system 80 to turn on the fixation lamp 82a based on the previous fixation lamp setting using the examination setting screen 210. This guides the line of sight (in other words, the fixation position) of the subject's eye onto the optical axis L. Therefore, the macula on the fundus is positioned on the optical axis L. The control unit 100 also controls the target projection optical system 70 to project an alignment target onto the cornea. Furthermore, the control unit 100 controls the anterior eye observation optical system 40 to sequentially acquire anterior eye observation images. For example, such anterior eye observation images may be displayed on the photographing screen 250 on the touch panel 120.

[0076] 6 is an example of the photographing screen 250. At least an anterior eye observation image 212, a front fundus image 213, and a Capture button 245 are displayed on the photographing screen 250. For example, the anterior eye observation image 212 and the front fundus image 213 are displayed as real-time observation images (in other words, moving images). The Capture button 245 is a button for capturing the front fundus image 213.

[0077] In this embodiment, the position of the photographing unit 3 is automatically moved with respect to the eye E based on the anterior-segment observation image 212 of the eye E. The control unit 100 detects an alignment target image 216 included in the anterior-segment observation image 212 by image processing of the anterior-segment observation image 212. For example, the alignment target image 216 may be detected based on luminance information of the anterior-segment observation image 212, and the alignment target image may be fitted to an ellipse, with the center of the ellipse being the corneal apex position.

[0078] Next, the control unit 100 controls the drive unit 8 to adjust the alignment state of the photographing unit 3 with respect to the subject's eye E. Because the control unit 100 turns on the fixation lamp 82a, the control unit 100 sets the alignment position in the X and Y directions so that the optical axis L coincides with the center position of the alignment target image 216 (in other words, the corneal vertex position). The control unit 100 also calculates the amount of deviation in the X and Y directions based on the center position of the alignment target image 216, and moves the photographing unit 3 in the X and Y directions so that the amount of deviation falls within an allowable range. Furthermore, the control unit 100 sets the alignment position in the Z direction based on the alignment target image 216. The control unit 100 also calculates the amount of deviation in the Z direction with respect to the alignment position by comparing the image ratio between the image spacing of the target image at infinity and the image spacing of the target image at a finite distance, and moves the photographing unit 3 in the Z direction so that the amount of deviation falls within an allowable range. When automatic alignment between the subject's eye E and the photographing unit 3 is completed, the photographing screen 250 displays a frontal fundus image 213.

[0079] When the examiner fixates the eye E on the fixation light 82a and the alignment is completed, the examiner operates the Capture button 245. Based on the input of the operation signal from the Capture button 245, the control unit 100 performs focus adjustment and captures a frontal fundus image 214.

[0080] When the control unit 100 captures (captures) the frontal fundus image 214, it transitions the display screen on the touch panel 120 from the imaging screen 250 in FIG. 6 to a confirmation screen 260 in FIG. 7. FIG. 7 is an example of the confirmation screen 260. The confirmation screen 260 is a screen for confirming the imaging results. The confirmation screen 260 displays the frontal fundus image 214 obtained by the capture. In addition, the confirmation screen 260 may allow various operations to be input, such as re-imaging, saving data, printing, creating and outputting a report, etc. In this embodiment, after the report is generated and output, the series of processes in the standard imaging mode is terminated.

[0081] <Panorama shooting mode> Next, the panoramic photography mode of this embodiment will be described. The panoramic photography mode is a mode in which the line of sight of the subject's eye E is fixed at any multiple positions, and photography is performed multiple times. More specifically, this mode presents one fixation light to the subject's eye E, and photographs are taken in sequence of predetermined fundus positions corresponding to each fixation position. Therefore, the examiner sets in advance which of the multiple fixation lights from the first fixation light 150 and the second fixation light 151 to turn on and in what order to turn them on.

[0082] In the panoramic imaging mode of this embodiment, imaging is performed with the first fixation light 150 and the second fixation light 151 presented to the subject's eye E, always including a state in which the first fixation light 150 is presented to the subject's eye E. At this time, imaging is performed in a predetermined imaging order, with the first fixation light 150 being presented to the subject's eye E first, followed by the second fixation light 151. Therefore, the control unit 100 controls the display of the examination setting screen 230 so that after selecting one of the fixation lights possessed by the first fixation light 150, the other fixation lights possessed by the first fixation light 150 and the fixation lights possessed by the second fixation light 151 can be selected in any order. Furthermore, the control unit 100 controls the display of the imaging screen so that an imaging order button 218 (described later), which indicates the position of the fixation light to be presented to the subject's eye E and the imaging order, appears only on the imaging screen when the second or subsequent second fixation lights 151 are used.

[0083] 8 to 12 are examples of the examination setting screen 230. Fig. 8 is a first setting screen 132 for setting the fixation light to be presented first to the subject's eye. Fig. 9 is a second setting screen 133 for setting the fixation light to be presented second or subsequent times to the subject's eye. Fig. 10 is the second setting screen 133 in a state in which the order in which the fixation lights are turned on for the subject's eye (in other words, the order in which images are taken) is displayed.

[0084] The examiner operates the touch panel 120 to select an operation button (not shown) to call up a fixation light setting screen for the panoramic imaging mode. Based on an operation signal input from the operation button (not shown), the control unit 100 first causes the touch panel 120 to display a first setting screen 132 of FIG. 8. The first setting screen 132 displays only selection buttons 86a, 86b, and 86c of the first fixation light selection button 86, which correspond to the fixation lights 82a, 82b, and 82c of the first fixation light 150. When setting a fixation light for the left eye, the selection buttons 86a to 86c are displayed, whereas when setting a fixation light for the right eye, the selection buttons 86a, 86d, and 86e are displayed.

[0085] The examiner selects one of the selection buttons 86a to 86c displayed on the first setting screen 132, corresponding to the fixation light that the examiner wants the examinee's eye to fixate first. In this embodiment, a case where the examiner selects the selection button 86a will be exemplified. The control unit 100 changes the display color of the selection button 86a based on an operation signal input by the examiner's selection of the selection button 86a, and displays numbers indicating the order in which the fixation lights will be turned on (i.e., the shooting order for panoramic photography) superimposed on the selection button 86a. At the same time, the control unit 100 switches the first setting screen 132 to a second setting screen 133. The second setting screen 133 additionally displays selection buttons 86d and 86e of the first fixation light selection button 86 and selection buttons 88f to 88u of the second fixation light selection button 88.

[0086] On the second setting screen 133, the examiner sequentially selects the selection buttons corresponding to the fixation lights that the examiner wants to fixate the subject's eye second and subsequent times. In this embodiment, an example is given in which the examiner selects selection buttons 88f, 88l, 88n, 88g, 88u, and 88s in this order from the second fixation light selection buttons 88. At this time, the control unit 100 changes the display color of the selection buttons and superimposes numbers as needed based on the input of operation signals from each selection button. As a result, the positions of the fixation lights relative to the subject's eye and the order in which they will be turned on (photographing order) are displayed, as shown in FIG. 10.

[0087] After completing the selection of the first fixation light selection button 86 and the second fixation light selection button 88, the examiner operates the decision button 207. The control unit 100 reflects the setting of the fixation lights based on the operation signal input by the examiner's operation of the decision button 207. That is, the control unit 100 reflects the setting so that predetermined fixation lights are turned on in a predetermined order in the panoramic photography mode.

[0088] Next, the examiner operates the touch panel 120 to select an operation button (not shown) to call up the examination selection screen 220 shown in Fig. 5. For example, the examiner selects the left eye as the eye to be photographed, selects the panoramic photography button 203b, and operates the start button 206. Based on the operation signal input from the start button 206, the control unit 100 starts photographing the left eye in the panoramic photography mode.

[0089] The control unit 100 switches the examination setting screen 230 on the touch panel 120 to a photographing screen 255. FIG. 11 shows an example of the photographing screen 255 when the first fixation light is presented. The photographing screen 255 displays an anterior eye observation image 222, a frontal fundus image 223, and a Capture button 246. Based on the fixation light settings made in advance using the examination setting screen 230, the control unit 100 turns on the fixation light 82a designated as the first fixation light, projects an alignment target on the cornea, and sequentially acquires anterior eye observation images 222. The control unit 100 also detects an alignment target image 216 included in the anterior eye observation image 222 and adjusts the alignment state of the photographing unit 3 with respect to the subject's eye E. Note that the alignment when the fixation light 82a is presented to the subject's eye E is the same as that described above, and therefore will not be described here.

[0090] Furthermore, the control unit 100 acquires corneal shape information regarding the corneal shape of the subject's eye based on position information (e.g., coordinates) regarding the position of the alignment target image 216. For example, the control unit 100 calculates the corneal curvature R as corneal shape information based on the image ratio between the image interval of target images at infinity and the image interval of target images at finite distance. For example, the corneal curvature R may be calculated by referring to a calculation formula or a conversion table that associates the image ratio of target images with each corneal curvature R. Note that such a calculation formula or conversion table is determined based on experiments or simulations and stored in the storage unit 101. In addition, the corneal curvature when the subject's eye E fixates the first fixation lamp 150 (e.g., the fixation lamp 82a) is used for alignment when the subject's eye E fixates the second fixation lamp 151 (details will be described later).

[0091] The examiner operates the Capture button 246 when the subject's eye E fixates the fixation light 82a and alignment is complete. The control unit 100 performs focus adjustment based on the input of an operation signal from the Capture button 246, and photographs (captures) a front fundus image 233. After photographing (capturing) the front fundus image 233, the control unit 100 transitions the display screen on the touch panel 120 from the photographing screen 255 in FIG. 11 to a confirmation screen 256 in FIG. 12.

[0092] 12 is an example of a confirmation screen 256 when the first fixation light is presented. The confirmation screen 256 displays a front fundus image 234 obtained by capture. The confirmation screen 256 also displays a confirmation button 248 for confirming the front fundus image 234 in a state where a predetermined fixation light is presented. For example, the confirmation button 248 may also serve as a transition button for transitioning to the next photographing operation designated in the photographing order.

[0093] The examiner checks the fundus front image 234 on the confirmation screen 256 and operates the confirm button 248. Based on the operation signal input from the confirm button 248, the control unit 100 associates the fixation light (here, the fixation light 82a) presented to the subject's eye with the captured fundus front image 233, and stores the association in the storage unit 101. Then, the control unit 100 switches the confirmation screen 256 back to the photographing screen (photographing screen 257).

[0094] 13 is an example of the photographing screen 257 when a second or subsequent second fixation light is presented. In addition to an anterior eye observation image 222, a frontal fundus image 223, and a Capture button 246, a photographing order button 218 is displayed on the photographing screen 257. The photographing order button 218 is a button that indicates the position of the fixation light to be presented to the subject's eye and the photographing order. For example, the photographing order button 218 is an icon that schematically indicates the position of the fixation light, and is configured by arranging each icon in a specified order.

[0095] Here, since the photographing with the first fixation light 150 (i.e., the fixation light 82a) presented has already been completed, the control unit 100 causes the icon 218a corresponding to the first photographing order to be displayed in the photographing order button 218 in a pre-grayed out state. Also, the control unit 100 does not accept input of an operation signal based on the operation of the icon 218a. On the other hand, the icons corresponding to the second and subsequent photographing orders are active, and are able to accept operation signals based on the operation of each icon.

[0096] The control unit 100 turns on the second designated fixation light 82f based on the previous fixation light setting using the examination setting screen 230. This guides the line of sight (fixation position) of the subject's eye to a position away from the optical axis L. Therefore, the peripheral part of the fundus is positioned on the optical axis L. The control unit 100 also adjusts the alignment state of the imaging unit 3 with respect to the subject's eye E.

[0097] When the fixation lamp 82f is presented to the eye E, the line of sight of the eye E is tilted relative to the optical axis L, causing the peripheral cornea to be positioned on the optical axis L. The central and peripheral corneal regions have different curvatures, which tends to distort the ring pattern of the alignment target image 216. Also, the separation amount of the corneal apex position relative to the pupil center position is increased. Therefore, when the fixation lamp 82f is presented, alignment is performed based on at least one of the corneal curvature R of the eye E and positional information related to the pupil position of the eye E.

[0098] The control unit 100 detects the alignment target image 216 and the pupil by image processing of the anterior-segment observation image 222. For example, the boundary between the pupil and the iris may be detected by edge detection or the like of the anterior-segment observation image 222, and the boundary may be fitted to an ellipse, with the center of the ellipse being set as the pupil center position. Furthermore, since the control unit 100 turns on the fixation lamp 82f, it sets the alignment position in the X and Y directions so that the optical axis L coincides with the pupil center position. The control unit 100 calculates the amount of deviation in the X and Y directions based on the pupil center position, and moves the imaging unit 3 in the X and Y directions so that the amount of deviation falls within an allowable range.

[0099] Furthermore, the control unit 100 calculates a deviation amount ΔWD of the working distance with respect to an alignment position (reference position) in the Z direction determined based on the corneal curvature R acquired while the subject's eye is fixating on the first fixation light 150 (fixation light 82a), thereby setting a new alignment position. For example, the control unit 100 calculates the deviation amount ΔWD of the working distance using the following formula, and sets the new alignment position by subtracting the deviation amount ΔWD from the reference position in the Z direction. In the formula, R represents the corneal curvature of the subject's eye E, and L represents the radius of the alignment target image 216 on the imaging element 47. a(R), b(R), and c(R) are quadratic expressions of the corneal curvature R, and α, β, and γ are predetermined coefficients.

[0100] ΔWD[mm]=a(R)・L2+b(R)・L+c(R) a(R) = αa·R2 + βa·R + γa b(R) = αb·R2 + βb·R + γb c(R) = αc·R2 + βc·R + γc

[0101] The control unit 100 moves the photographing unit 3 in the Z direction so that the amount of deviation (i.e., the deviation amount ΔWD) relative to the new alignment position in the Z direction falls within an allowable range. Furthermore, the control unit 100 photographs (captures) a front image of the fundus in a state where the examiner fixates on the fixation light 82f, based on an operation signal input from the Capture button 246 by the examiner.

[0102] 14 is an example of a confirmation screen 258 when a second fixation light (here, fixation light 82f) is presented. The confirmation screen 258 displays a fundus front image 234, a photographing order button 218, and a confirm button 248. When the control unit 100 photographs (captures) a front fundus image, it grays out the icon 218b of the photographing order button 218 corresponding to the second image to be photographed. Furthermore, based on an operation signal input from the confirm button 248 by the examiner, the control unit 100 associates the fixation light 82f with the captured front fundus image 233, and stores the association in the storage unit 101.

[0103] The control unit 100 switches on and off the second to n-th fixation lights based on the input of a completion signal indicating that capture of the front fundus images 234 has been completed, in accordance with the photographing order set on the examination setting screen 230. The control unit 100 also adjusts the alignment again by using different parameters depending on the first fixation light 150 or the second fixation light 151. For example, by repeating the fixation light switching, alignment, and capture, multiple front fundus images 234 are captured in sequence. Then, when capture of the front fundus images 234 with all fixation lights presented has been completed, the control unit 100 synthesizes a panoramic image.

[0104] Note that each front fundus image always includes a front image of the center of the fundus. For example, since the second fixation light selection button 88 is configured to be displayed based on the examiner's selection of the first fixation light selection button 86, a front image of the center of the fundus is incorporated into the first photographing order. For example, since the photographing order button 218 is configured to appear on the photographing screen after the second or subsequent photographing orders are entered, skip operations, etc., described below, are substantially prohibited for the first photographing operation with the first fixation light presented.

[0105] The control unit 100 aligns each frontal fundus image and performs synthesis processing. For example, if the frontal fundus image at the center is used as a reference, it is easy to arrange the frontal fundus image at the peripheral portion adjacent to the frontal fundus image at the center. Alternatively, it is easy to arrange the frontal fundus image at the peripheral portion so that a portion of the frontal fundus image overlaps with the frontal fundus image at the center. Therefore, the presence of the frontal fundus image at the center allows for efficient panoramic synthesis.

[0106] 15 is an example of a panoramic image 215. After the control unit 100 has finished combining the respective frontal fundus images, the control unit 100 may display the panoramic image 215 on a confirmation screen 258. Alternatively, the control unit 100 may individually display the frontal fundus images that are the basis of the panoramic image on the confirmation screen 258. After that, a report is generated and output, and then the series of processes in the panoramic photography mode is terminated.

[0107] As described above, for example, the fundus photographing device of this embodiment has a first fixation target for guiding the line of sight of the subject's eye to a position on or near the photographing optical axis of the photographing optical system, and a second fixation target for guiding the line of sight of the subject's eye to a position away from the photographing optical axis and around the first fixation target. It is possible to switch between a standard photographing mode in which one frontal fundus image is captured with the first or second fixation target presented to the subject's eye, and a panoramic photographing mode in which multiple frontal fundus images are captured, including both a first state in which the first fixation target is presented to the subject's eye and a second state in which the second fixation target is presented to the subject's eye. In the panoramic photographing mode, the fixation optical system is controlled according to a predetermined photographing order, so that the line of sight is guided according to the predetermined photographing order. The fundus photographing device of this embodiment captures multiple frontal fundus images, always including a frontal fundus image with the first fixation target presented to the subject's eye, thereby enabling good panoramic photographing. For example, it becomes easy to perform a synthesis process of superimposing overlapping portions of each frontal fundus image using the frontal fundus image in a state where the first fixation target is presented as a reference.

[0108] Furthermore, for example, in the fundus imaging device of this embodiment, in the panoramic imaging mode, the fixation optical system is controlled in an imaging order in which the first fixation target is presented first, followed by the second fixation target. For example, the cornea of ​​the subject's eye changes in curvature more significantly the further away from the central cornea. Therefore, the reliability of the alignment between the subject's eye and the imaging device and the frontal fundus image obtained based on the alignment is reduced in the peripheral corneal region compared to the central corneal region. Furthermore, for example, when the subject tilts their line of sight more significantly (i.e., the farther away the fixation target is presented from the imaging optical axis), the corneal reflection image is replaced by a scleral reflection image, which also reduces the reliability of the alignment and the frontal fundus image. However, in the fundus imaging device of this embodiment, the first fixation target is presented first, allowing for more reliable imaging, resulting in improved imaging accuracy.

[0109] Furthermore, for example, the fundus imaging device of this embodiment can set a predetermined imaging order in the panoramic imaging mode, and the fixation optical system is controlled based on the set imaging order. For example, the examiner can appropriately change the fundus region to be photographed and the total number of images to be photographed according to the purpose of the examination of the subject's eye, a disease of the subject's eye, etc., thereby improving operability.

[0110] Furthermore, for example, the fundus photographing device of this embodiment displays a first selection screen including a first selection button for selecting a first fixation target, and a second selection screen different from the first selection screen including a second button for selecting a second fixation target, and completes setting of a predetermined photographing order when an operation signal is received from both the first selection button and the second selection button. For example, this requires the examiner to select a first fixation target, thereby maintaining a certain level of reliability and photographing accuracy.

[0111] Furthermore, for example, in the fundus imaging device of this embodiment, in a first state in which a first fixation target is presented to the subject's eye, corneal topography information regarding the corneal topography is acquired based on second position information regarding the position of the target image projected onto the cornea of ​​the subject's eye, and in a second state in which a second fixation target is presented to the subject's eye, the imaging device is moved in the working distance direction based on the corneal topography information acquired in the first state. For example, by acquiring highly reliable corneal topography information that differs for each subject's eye in the first state in which a first fixation target is presented to the subject's eye, it is possible to correct deviations in the working distance direction in consideration of changes in the corneal curvature in the second state in which a second fixation target is presented to the subject's eye. Therefore, accurate alignment can be performed even in the second state.

[0112] <Modification> The techniques disclosed in the above embodiments are merely examples. Therefore, the techniques exemplified in the above embodiments may be modified. For example, it is possible to implement only some of the techniques exemplified in the above embodiments.

[0113] In this embodiment, the fundus photographing device 1 is configured to photograph multiple frontal fundus images of the subject's eye E and combine them into a panoramic image, but the present invention is not limited to this. For example, the frontal fundus images photographed by the fundus photographing device 1 may be transferred to a device or computer different from the fundus photographing device 1. Then, the multiple frontal fundus images may be panoramic-combined in the other device or computer to obtain the panoramic image 215.

[0114] In this embodiment, the fixation light 82a of the first fixation light 150 is presented to the subject's eye when the standard or panoramic imaging mode is applied to the subject's eye, but the present invention is not limited to this. For example, the fixation light 82b or 82c of the first fixation light 150 may be presented to the subject's eye.

[0115] For example, fixation light 82a is positioned on optical axis L, while fixation light 82b or 82c is positioned near optical axis L. When the subject's eye directs its gaze toward fixation light 82b or 82c, the corneal region positioned on optical axis L changes, which may disrupt the ring pattern of alignment target image 216. Note that because fixation light 82b or 82c is positioned closer to optical axis L than second fixation light 151, the degree of disruption of the ring pattern and the separation between the corneal apex position and the pupil center position are smaller than when second fixation light 151 is presented. Therefore, when fixation light 82b or 82c is presented to the subject's eye, alignment may be performed based on the pupil center position only in the X direction, and alignment may be performed based on alignment target image 216 in the Y and Z directions.

[0116] In the present embodiment, in photographing the subject's eye E in the panoramic photography mode, the n-th first fixation light 150 or second fixation light 151 is automatically turned on and the subject's eye E is aligned with the photography unit 3, and then the examiner manually captures the frontal fundus image 223 by pressing the Capture button 246. However, the present embodiment is not limited to this. For example, the examiner may automatically turn on the first fixation light 150 or second fixation light 151 according to the photography order, align the subject's eye E with the photography unit 3, and capture the frontal fundus image 223 by pressing the start button 206 on the examination selection screen 220. In other words, panoramic photography of the fundus of the subject's eye E may be performed fully automatically.

[0117] In the panoramic photography mode, icons of the photography order button 218 are arranged on the photography screen 257 based on the photography order previously set on the examination setting screen 230, and the frontal fundus images 234 are photographed sequentially. Here, the examiner may be configured to be able to skip the presentation of a fixation light scheduled after the fixation light currently being gazed at by the subject's eye E. In other words, if the examiner determines that photography at at least one of the second or subsequent scheduled fixation positions is unnecessary, the examiner may be configured to be able to skip that photography.

[0118] In this case, the examiner may check the photographing order button 218 during panoramic photographing of the subject's eye, select an active icon indicating the position of the fixation light to be next presented to the subject's eye, and then press the Capture button 246. As an example, with the second fixation light presented to the subject's eye, the examiner may select an icon indicating the position of the fourth scheduled fixation light, and then press the Capture button 246 for the second photographing. Upon completing capture of the frontal fundus image presented with the second fixation light, the control unit 100, based on an operation signal input from the photographing order button 218, cancels the illumination of the third scheduled predetermined fixation light and turns on the fourth scheduled predetermined fixation light, thereby skipping photographing the frontal fundus image presented with the third fixation light. At this time, the control unit 100 may also visualize the skip of photographing by drawing a diagonal line through the icon indicating the position of the third fixation light on the photographing order button 218 and disables input of an operation signal.

[0119] In the present embodiment, the corneal curvature R acquired when the first fixation light 150 is presented to the subject's eye is used for alignment in the Z direction when the second fixation light 151 is presented to the subject's eye, but the present invention is not limited to this. For example, the corneal curvature R acquired when the first fixation light 150 is presented and position information of the alignment target image 216 at this time may be used for alignment in the Z direction when the second fixation light 151 is presented to the subject's eye. As an example, in this case, the movable range of the imaging unit 3 may be limited with respect to the alignment position in the Z direction when the second fixation light 151 is presented to the subject's eye, based on the position information of the alignment target image 216 when the first fixation light 150 is presented to the subject's eye. This allows for more accurate alignment.

[0120] When capturing a frontal image of the fundus of the subject's eye in this embodiment, each alignment position may be set taking into consideration the pupil diameter of the subject's eye E. Fig. 16 is a diagram showing the alignment positions in the standard imaging mode. Fig. 17 is a diagram showing the alignment positions in the panoramic imaging mode. The alignment position here refers to the positional relationship between the subject's eye E and the optical axis L of the fundus imaging device 1, which is set during imaging.

[0121] In the front imaging optical system 10, two illumination areas P1 and P2 are formed as images of two light sources on the pupil conjugate plane at positions (for example, positions symmetrical about the optical axis L) different from the optical axis L (the center of the light-receiving area J in the example shown in FIG. 16) on the pupil conjugate plane. Also, the light-receiving area J is formed between the two illumination areas P1 and P2 on the pupil conjugate plane (for example, a position through which the optical axis L passes). Note that the illumination areas P1 and P2 and the light-receiving area J are shown in FIGS. 16 and 17 merely for the sake of convenience.

[0122] 16, when the pupil diameter is sufficiently large relative to the overall width of the irradiation areas P1 and P2 and the light-receiving area J, it is possible for both lights passing through the two irradiation areas P1 and P2 to be irradiated onto the fundus Er. In this case, the alignment position between the subject's eye E and the optical axis L may be set to a first reference position that assumes that the two irradiation areas P1 and P2 and the one light-receiving area J of the front imaging optical system 10 all fall within the pupil area of ​​the subject's eye E. For example, in the standard imaging mode, the control unit 100 sets the alignment position where the pupil center position and the optical axis L coincide (or nearly coincide) with each other as the first reference position. Note that when the subject's eye E gazes straight ahead, the corneal vertex position and the pupil center position are at the same (or nearly the same) position on the anterior segment observation image.

[0123] On the other hand, when panoramic photography of the subject's eye E is performed (i.e., when the panoramic photography mode is applied), it is necessary to capture multiple frontal fundus images constituting the panoramic image in as short a time as possible. Therefore, multiple frontal fundus images may be captured at intervals long enough that miosis does not recover. Miosis reduces the pupil diameter. In this case, if the alignment position is set so that the optical axis L coincides with the center position of the pupil, as shown in FIG. 16, the light projected through the irradiation areas P1 and P2 will be vignetted by the iris, increasing the possibility that the fundus Er will not be properly photographed. Therefore, as shown in FIG. 17, the control unit 100 sets the alignment position between the subject's eye E and the optical axis L to a second reference position that is decentered (offset) from the first reference position.

[0124] The second reference position in this embodiment is a position where a portion of at least one of the illumination areas P1, P2 and the light-receiving area J of the front imaging optical system 10 is assumed to be outside the pupil area of ​​the subject's eye. Specifically, the second reference position is a position where one of the two illumination areas P1, P2 and the light-receiving area J of the front imaging optical system 10 is within the pupil area, and the other of the two illumination areas P1, P2 is outside the pupil area. By intentionally positioning one of the two illumination areas P1, P2 outside the pupil area, the other illumination area and the light-receiving area are more likely to be positioned within the pupil area. As a result, the fundus Er is properly photographed. [Explanation of symbols]

[0125] 1 Fundus photography device 8 Drive unit 10 Frontal imaging optical system 40 Anterior segment observation optical system 70 Index projection optical system 80 Fixation target projection optical system 81 Fixation target unit 86 First fixation light selection button 88 Second fixation light selection button 100 control section 120 Touch Panel 132 First setting screen 133 Second setting screen 150 1st fixation light 151 Second fixation light 210,230 Inspection setting screen 220 Examination selection screen 250,255 shooting screen 260,256 Confirmation screen

Claims

1. an imaging optical system for capturing a front image of the fundus of the subject's eye; a fixation optical system capable of switching the presentation position of a fixation target for changing the line of sight of the subject's eye; a driving means for adjusting the positional relationship between the subject's eye and an imaging means including the imaging optical system and the fixation optical system; a control means for controlling the driving means to move the photographing means relative to the subject's eye and for controlling the photographing optical system to photograph the front image of the fundus of the subject's eye; Equipped with the fixation optical system includes a first fixation target for guiding the line of sight of the subject's eye to a position on or near an imaging optical axis of the imaging optical system, and a second fixation target for guiding the line of sight of the subject's eye to a position away from the imaging optical axis and around the first fixation target, The control means A standard photography mode for photographing one position on the fundus and a panoramic photography mode for photographing multiple positions on the fundus in sequence can be selectively executed; A fundus photography device that guides the position corresponding to the first fixation target so that it is photographed in the panoramic photography mode.

2. 2. The fundus imaging apparatus according to claim 1, A fundus photography device characterized in that when photographing multiple positions in sequence in the panoramic photography mode, the photographing order is fixed so that the photographing of the position corresponding to the first fixation target is first, and the photographing of the position corresponding to the second fixation target is second or later.

3. 3. The fundus imaging apparatus according to claim 2, a projection optical system that projects a projection light beam onto the cornea of ​​the subject's eye; an anterior-segment observation optical system that acquires an anterior-segment observation image of the subject's eye, the anterior-segment observation image including a target image formed by the projected light beam; Equipped with the imaging means further includes the projection optical system and the anterior eye segment observation optical system, The control means acquiring position information relating to the position of the target image when capturing an image of the position corresponding to the first fixation target, and further acquiring corneal shape information relating to the corneal shape based on the position information; When photographing a position corresponding to the second fixation target, alignment of the photographing means in a working distance direction is controlled based on the corneal shape information.

4. 5. The fundus imaging apparatus according to claim 1, The control means displays, on a display means, a sequence setting GUI for setting a sequence of photographing in the panoramic photographing mode, and The fundus photographing apparatus is characterized in that the control means controls the fixation optical system based on the predetermined photographing order set based on an operation input via the GUI.

5. 5. The fundus imaging apparatus according to claim 4, The GUI includes: a first selection screen on which a first selection button for selecting the first fixation target is arranged, and a second selection screen different from the first selection screen on which a second button for selecting the second fixation target is arranged, When an operation signal is received from both the first selection button and the second selection button, setting of the predetermined photographing order is completed. A fundus photographing device characterized by:

6. an imaging optical system for capturing a front image of the fundus of the subject's eye; a fixation optical system capable of switching the presentation position of a fixation target for changing the line of sight of the subject's eye, the fixation optical system including: a first fixation target for guiding the line of sight of the subject's eye to a position on or near an imaging optical axis of the imaging optical system; and a second fixation target for guiding the line of sight of the subject's eye to a position away from the imaging optical axis and around the first fixation target; a driving means for adjusting the positional relationship between the subject's eye and an imaging means including the imaging optical system and the fixation optical system; A fundus photography program executed by a fundus photography device comprising: When executed by a processor of the fundus imaging device, causing the fundus photographing device to execute a control step of controlling the driving means to move the photographing means relative to the subject's eye and controlling the photographing optical system to photograph a front image of the fundus of the subject's eye; The control step A standard photography mode for photographing one position on the fundus and a panoramic photography mode for photographing multiple positions on the fundus in sequence can be selectively executed; a fundus photography program that guides the user to photograph a position corresponding to the first fixation target in the panoramic photography mode;

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