JP7023315B2 - Ophthalmologic photography equipment - Google Patents

Description

The present invention relates to an ophthalmologic imaging apparatus.

Diagnostic imaging occupies an important position in the field of ophthalmology, and in recent years, scanning laser ophthalmoscopes (SLOs) and optical coherence tomography have been increasingly used. The SLO is a device that forms an image by scanning the fundus of the eye at high speed with a weak laser beam using a confocal optical system, and is used for screening and diagnosis of eye diseases. Optical coherence tomography is an optical measuring device that applies a technique called optical coherence tomography (OCT), and forms cross-sectional images, three-dimensional images, and functional images by scanning the two-dimensional and three-dimensional regions of the fundus. do. Optical coherence tomography is also used for imaging the cornea and the like.

Generally, the resolution (horizontal resolution) δ of an optical photographing apparatus is represented by δ = 0.61λ / NA (where λ indicates the wavelength of light and NA indicates the numerical aperture of the objective lens). Therefore, the larger the diameter of the beam used for photographing, the higher the resolution. That is, the larger the beam diameter, the better the image quality.

On the other hand, when the shooting angle of view is increased in a scanning fundus photography device such as an SLO or an optical coherence tomography, the focal point of the beam projected on the central part of the shooting range (for example, the surface of the fundus) coincides (almost) with the desired part. However, the focal point of the beam projected on the peripheral part may be formed at a position deviating from the desired part. Therefore, a small-diameter beam is used in a scanning fundus photography apparatus capable of wide-angle photography.

As described above, the larger the beam diameter is better for improving the image quality, and the smaller the beam diameter is better for expanding the angle of view. That is, regarding the beam diameter, there is a trade-off relationship between the image quality and the angle of view.

Japanese Unexamined Patent Publication No. 2014-54484

An object of the present invention is to improve an ophthalmologic photographing apparatus capable of changing the angle of view, and more specifically, an ophthalmologic photographing apparatus capable of acquiring images of various angles of view with suitable image quality. Is to provide.

The ophthalmologic imaging apparatus according to the embodiment includes a data acquisition unit, an image forming unit, an angle of view changing unit, a beam size changing unit, and a control unit. The data collection unit scans the fundus of the eye to be inspected using a light beam and collects data. The image forming unit forms an image of the fundus based on the data collected by the data collecting unit. The angle of view changing unit includes a light deflector having a variable deflection angle for deflecting the light beam, and has a configuration for changing the angle of view by changing the deflection angle of the light beam by the light deflector . The beam size changing unit changes the size of the light beam. When the beam size is changed, the control unit controls the optical deflector of the angle of view changing unit so as to set the angle of view according to the new beam size.

According to the present invention, it is possible to provide an ophthalmologic photographing apparatus capable of acquiring images of various angles of view with suitable image quality.

It is a schematic diagram which shows an example of the structure of the ophthalmologic imaging apparatus which concerns on embodiment. It is a schematic diagram which shows an example of the structure of the ophthalmologic imaging apparatus which concerns on embodiment. It is a schematic diagram which shows an example of the structure of the ophthalmologic imaging apparatus which concerns on embodiment. It is a schematic diagram which shows an example of the structure of the ophthalmologic imaging apparatus which concerns on embodiment. It is a schematic diagram which shows an example of the structure of the ophthalmologic imaging apparatus which concerns on embodiment. It is a schematic diagram which shows an example of the structure of the ophthalmologic imaging apparatus which concerns on embodiment. It is a schematic diagram for demonstrating an example of the structure of the ophthalmologic imaging apparatus which concerns on embodiment. It is a schematic diagram for demonstrating an example of the structure of the ophthalmologic imaging apparatus which concerns on embodiment. It is a schematic diagram for demonstrating an example of the structure of the ophthalmologic imaging apparatus which concerns on embodiment. It is a schematic diagram for demonstrating an example of the structure of the ophthalmologic imaging apparatus which concerns on embodiment. It is a flowchart which shows an example of the operation of the ophthalmologic imaging apparatus which concerns on embodiment. It is a schematic diagram which shows an example of the structure of the ophthalmologic imaging apparatus which concerns on a modification. It is a schematic diagram which shows an example of the structure of the ophthalmologic imaging apparatus which concerns on a modification.

An exemplary embodiment of the ophthalmologic imaging apparatus will be described below. The contents of the cited document and publicly known techniques can be incorporated into embodiments.

The ophthalmologic imaging apparatus according to the embodiment scans the posterior eye portion with a light beam to acquire a distribution of predetermined data (eg, image, layer thickness distribution, lesion distribution). Examples of such ophthalmologic imaging devices are SLOs and optical coherence tomography. Hereinafter, an ophthalmologic imaging device that combines an SLO and an optical coherence tomography will be described in detail.

Hereinafter, unless otherwise specified, the left-right direction is defined as the X direction, the vertical direction is defined as the Y direction, and the front-back direction (depth direction) is defined as the Z direction when viewed from the subject. The X, Y, and Z directions define a three-dimensional Cartesian coordinate system.

<Optical system 100>
Examples of the optical system of the ophthalmologic imaging apparatus are shown in FIGS. 1 to 4B. The ophthalmologic imaging device can operate in a plurality of imaging modes. For example, there are a wide-angle shooting mode and a high-magnification shooting mode as operation modes related to the size of the shooting range (angle of view, magnification). The switching of the angle of view is realized, for example, by selectively using two or more objective lenses having different refractive powers. Alternatively, the angle of view may be changed by changing the deflection angle of the light beam by the light deflector (optical scanner). The method and configuration for changing the angle of view are not limited to these.

FIG. 1 shows an example of an optical system in a wide-angle shooting mode. FIG. 2 shows an example of an objective lens system for switching the angle of view. FIG. 3 shows an example of the optical system of the ophthalmologic imaging apparatus in the high magnification imaging mode. Reference numeral P in FIGS. 1 and 3 indicates a position optically conjugate with the fundus Ef (fundus conjugate position), and reference numeral Q indicates a position optically conjugate with the pupil of the eye E to be inspected (pupil conjugate position). .. 4A and 4B show an example of a beam size changing system for switching the size (beam size) of the cross section of the light beam used for photographing. In a typical embodiment, the beam diameter is used as a parameter representing the beam size.

The optical system 100 scans the fundus Ef using a light beam and collects data. Therefore, the optical system 100 includes a projection system that projects a light beam onto the eye E to be inspected via the objective lens system 110 and a light receiving system that receives the return light of the projected light beam via the objective lens system 110. include. An image of the fundus Ef is formed based on the output from the light receiving system (that is, the data collected by the data acquisition unit). The optical system 100 includes an SLO optical system 130 and an OCT optical system 140. The SLO optical system 130 includes an SLO projection system and an SLO light receiving system. The OCT optical system 140 includes an OCT projection system and an OCT light receiving system.

The ophthalmologic photographing apparatus is provided with an anterior ocular segment photographing system 120 for observing and photographing the anterior ocular segment. The optical system 100, the objective lens system 110, and the anterior ocular segment photographing system 120 are moved in the X direction, the Y direction, and the Z direction. The anterior segment image obtained by the anterior segment imaging system 120 is used for alignment and tracking.

<Objective lens system 110>
In an exemplary embodiment, an objective lens (unit) is prepared for each shooting mode, and an objective lens unit corresponding to the selected shooting mode is selectively used. In this embodiment, as shown in FIG. 2, the objective lens unit 110A for a wide-angle shooting mode (for example, an angle of view of 100 degrees) and the objective lens unit 110B for a high magnification shooting mode (for example, an angle of view of 50 degrees) are provided. , Are selectively arranged in the optical path of the optical system 100.

The objective lens system 110 includes an angle of view changing mechanism 115 in addition to the objective lens units 110A and 110B. The angle of view changing mechanism 115 includes, for example, a known rotation mechanism or slide mechanism, and selectively (exclusively) arranges the objective lens units 110A and 110B in the optical path. The angle of view changing mechanism 115 arranges the objective lens unit 110A (110B) in the optical path so that the optical axis of the objective lens unit 110A (110B) substantially coincides with the optical axis O of the optical system 100.

The angle of view changing mechanism 115 may include a configuration for manually moving the objective lens units 110A and 110B. In this case, it is possible to provide a type detection unit for detecting the type of the objective lens unit arranged in the optical path, specify the photographing mode from the detection result, and execute the control according to the specific result. The angle of view changing mechanism 115 may have a configuration for electrically (and even automatically) moving the objective lens units 110A and 110B. In this case, the control unit 200, which will be described later, sends a control signal for arranging the objective lens unit corresponding to the selected shooting mode in the optical path to the angle of view changing mechanism 115.

The objective lens unit 110A for the wide-angle shooting mode includes lenses 111A and 112A, a dichroic mirror DM1A, and a concave lens 113A. The dichroic mirror DM1A couples the optical path of the optical system 100 and the optical path of the anterior ocular segment photographing system 120. The dichroic mirror DM1A transmits the light guided by the optical system 100 and reflects the light for photographing the anterior segment of the eye. A fundus conjugate position P is arranged between the dichroic mirror DM1A and the concave lens 113A.

The objective lens unit 110B for the high magnification shooting mode includes a lens 111B and a dichroic mirror DM1B. The dichroic mirror DM1B has the same function as the dichroic mirror DM1A.

The dichroic mirror DM1A and the dichroic mirror DM1B are arranged at (almost) the same position in the optical path of the optical system 100. This eliminates the need to adjust the position and orientation of the anterior ocular segment imaging system 120 when the imaging mode is switched.

In an exemplary embodiment, a single dichroic mirror can be configured to be shared by multiple objective lens units. For example, in the example shown in FIG. 2, the dichroic mirrors DM1A and DM1B may be the same member. That is, a configuration can be applied in which the objective lens unit 110A including only the lenses 111A and 112A and the concave lens 113A and the objective lens unit 110B including only the lens 111B are selectively used.

The objective lens system 110 can be moved along the optical axis O. That is, the objective lens system 110 can be moved in the Z direction with respect to the optical system 100. As a result, the focal position of the SLO optical system 130 and the focal position of the OCT optical system 140 are changed.

In an exemplary embodiment, three or more objective lens units can be selectively used. For example, an objective lens unit for a high magnification shooting mode, a medium magnification shooting mode, and a low magnification shooting mode, and an angle of view changing mechanism for selectively arranging these in the optical path may be provided.

Hereinafter, the state in which the objective lens unit 110A is arranged in the optical path will be mainly described. Unless otherwise specified, the same or similar matters in the state where the objective lens unit 110B is arranged will be omitted.

<Front eye photography system 120>
The anterior eye imaging system 120 includes an anterior eye imaging light source 121, a lens 122, an anterior eye imaging camera 123, an imaging lens 124, and a beam splitter BS1. The beam splitter BS1 couples the optical path of the anterior eye illumination light and the optical path of the return light.

The front eye illumination light source 121 includes an infrared light source such as an infrared LED. The anterior segment illumination light emitted by the anterior segment illumination light source 121 is refracted by the lens 122, reflected by the beam splitter BS1 toward the dichroic mirror DM1A, and reflected by the dichroic mirror DM1A toward the eye E to be inspected. The return light of the anterior eye illumination light from the eye E to be inspected is reflected by the dichroic mirror DM1A, transmitted through the beam splitter BS1, and focused on the anterior eye photographing camera 123 (detection surface of the image pickup element) by the imaging lens 124. Will be done. The detection surface of the image sensor corresponds to the pupil conjugate position Q (or its vicinity). The image pickup device is, for example, a CCD image sensor or a CMOS image sensor.

<SLO optical system 130 and OCT optical system 140>
The optical path of the SLO optical system 130 and the optical path of the OCT optical system 140 are coupled by a dichroic mirror DM2. In an exemplary embodiment, at least part of the SLO optical system 130 is a telecentric optical system and at least a part of the OCT optical system 140 is a telecentric optical system, and the optical paths of these telecentric optical systems are coupled by a dichroic mirror DM2. The optical path. According to this example, even if the objective lens system 110 is moved to change the focal position of the optical system 100, the aberration of the pupil (for example, the exit pupil by the objective lens system 110) does not increase, so that the focus adjustment is facilitated. be able to.

<SLO optical system 130>
The SLO optical system 130 includes an SLO light source 131, a collimating lens 132, a beam splitter BS2, a condenser lens 133, a confocal diaphragm 134, a detector 135, an optical scanner 136, and a lens 137. The beam splitter BS2 couples the optical path of the SLO light projected on the eye E to be inspected and the optical path of the return light thereof.

A variable diaphragm 139 is provided between the collimating lens 132 and the beam splitter BS2. The variable diaphragm 139 is a diaphragm having a variable aperture size (opening diameter), and is used to change the beam size of SLO light. The variable diaphragm 139 may be a diaphragm member whose opening size can be mechanically changed, or may be a member such as a turret or a slide plate having a plurality of openings having different sizes. The variable diaphragm 139 may be configured to continuously change the size of the aperture or may be configured to change in stages.

The SLO light source 131 includes a laser diode, a super luminescent diode, a laser driven light source, and the like. The SLO light source 131 may be configured to output light having a wavelength that can be used for SLO and selectively output light having a different wavelength band. The SLO light source 131 corresponds to the fundus conjugate position P (or its vicinity).

The optical scanner 136 includes an optical scanner 136X that deflects light in the X direction and an optical scanner 136Y that deflects light in the Y direction. One of the optical scanners 136X and 136Y is a low-speed scanner (galvano mirror, etc.), and the other is a high-speed scanner (resonant mirror, polygon mirror, MEMS mirror, etc.). The reflective surface of the optical scanner 136Y corresponds to the pupil conjugate position Q (or its vicinity).

The opening formed in the confocal diaphragm 134 corresponds to the fundus conjugate position P (or its vicinity). The detector 135 includes, for example, an avalanche photodiode or a photomultiplier tube.

The light beam (SLO light) output from the SLO light source 131 is converted into a parallel light beam by the collimating lens 132, the beam size (beam diameter) is limited by the variable diaphragm 139, transmitted through the beam splitter BS2, and deflected by the optical scanner 136. Then, it is refracted by the lens 137, passes through the dichroic mirror DM2, and is projected onto the fundus Ef via the objective lens system 110. The return light of the SLO light projected on the fundus Ef travels in the same optical path in the opposite direction, is guided to the beam splitter BS2, is reflected by the beam splitter BS2, is focused by the condenser lens 133, and is collected by the confocal aperture 134. It passes through the opening and is detected by the detector 135.

<OCT optical system 140>
The OCT optical system 140 includes a focusing lens 141, an optical scanner 142, a collimating lens 143A (or collimating lens 143B), and an interference optical system 150. A collimating lens 143A is provided in the wide-angle shooting mode (see FIG. 1), and a collimating lens 143B is provided in the high-magnification shooting mode (see FIG. 3).

The focusing lens 141 is moved along the optical axis of the OCT optical system 140. As a result, the focal position of the OCT optical system 140 is changed independently of the SLO optical system 130. After the focusing state of the SLO optical system 130 and the OCT optical system 140 is adjusted by moving the objective lens system 110, the focusing state of the OCT optical system 140 can be finely adjusted by moving the focusing lens 141.

The optical scanner 142 includes an optical scanner 142X that deflects light in the X direction and an optical scanner 142Y that deflects light in the Y direction. Each of the optical scanner 142X and the optical scanner 142Y is, for example, a galvano mirror. The intermediate position between the two optical scanners 142X and 142Y corresponds to the pupil conjugate position Q (or its vicinity).

The collimating lens 143A (or 143B) guides the OCT light (measurement light) emitted from the fiber end c3 of the optical fiber f4 to the optical scanner 142 as a parallel light flux, and guides the return light of the measurement light from the fundus Ef to the fiber end c3. Condensate toward. The collimated lens 143A for the wide-angle shooting mode generates a parallel light flux (measurement light) with a first beam diameter, and the collimated lens 143B for a high magnification shooting mode generates a parallel light flux (measurement light) with a second beam diameter. The first beam diameter is smaller than the second beam diameter. That is, a relatively thin light beam is used in the wide-angle shooting mode, and a relatively thick light beam is used in the high-magnification shooting mode. Such a difference in beam diameter is realized, for example, by the difference between the refractive power of the collimating lens 143A and the refractive power of the collimating lens 143B.

Examples of the beam size change system 143 for selectively arranging the collimating lenses 143A and 143B in the optical path are shown in FIGS. 4A and 4B. The beam size changing system 143 includes a lens unit 143U including collimating lenses 143A and 143B, and a beam diameter changing mechanism 143C for moving the lens unit 143U.

The lens unit 143U is, for example, a turret or a slide plate to which the collimating lenses 143A and 143B are mounted. The beam diameter changing mechanism 143C includes, for example, a known rotation mechanism or slide mechanism, and selectively (mutually exclusively) arranges the collimating lenses 143A and 143B in the optical path. The beam diameter changing mechanism 143C moves the lens unit 143U so that the optical axis of the collimating lens 143A (143B) substantially coincides with the optical axis O1 of the OCT optical system 140. The operation of the beam diameter changing mechanism 143C is controlled by the control unit 200 described later.

It is also possible to selectively use three or more collimating lenses. The number of collimating lenses is determined, for example, according to the number of objective lens units. That is, the number of beam diameter options can be determined according to the number of shooting modes related to the angle of view. For example, a combination of an objective lens unit for high magnification shooting mode and a collimated lens for high magnification shooting mode, a combination of an objective lens unit for medium magnification shooting mode and a collimated lens for medium magnification shooting mode, and a low magnification shooting mode. It is possible to selectively use the combination of the objective lens unit for the purpose and the collimating lens for the low magnification shooting mode.

In this embodiment, a variable diaphragm and a plurality of collimating lenses selectively used are used as means for changing the beam size, but the present invention is not limited thereto. For example, a liquid lens or a movable lens (or a movable lens system) for changing the beam diameter can be applied.

The interferometric optical system 150 includes an OCT light source 151, fiber couplers 152 and 153, a reference prism 154, and a detector 155. Interferometric optical system 150 comprises, for example, a configuration for performing a swept source OCT or a spectral domain OCT. In swept source OCT, a tunable light source is used as the OCT light source 151 and a balanced photodiode is used as the detector 155. In the spectral domain OCT, a low coherence light source (broadband light source) is used as the OCT light source 151, and a spectroscope is used as the detector 155.

The OCT light source 151 emits, for example, a light beam L0 that emits light having a center wavelength of 1050 nm. The light L0 is guided to the fiber coupler 152 through the optical fiber f1 and is divided into the measurement light LS and the reference light LR.

The reference light LR is emitted from the fiber exit end c1 through the optical fiber f2, is converted into a parallel light beam by the collimated lens 156, folded back by the reference prism 154, is converted into a focused light beam by the collimating lens 157, and is incident on the fiber incident end c2. It is guided to the fiber coupler 153 through the optical fiber f3. The reference prism 154 is moved to change the optical path length of the reference light LR as in the conventional case. Further, a polarization controller, an attenuator, an optical path length correction member, and a dispersion compensation member may be provided in the optical path of the reference light.

On the other hand, the measurement light LS generated by the fiber coupler 152 is emitted from the fiber end c3 through the optical fiber f4, is converted into a parallel light beam by the collimated lens 143A or 143B, passes through the optical scanner 142 and the focusing lens 141, and is a dichroic mirror. It is reflected by DM2, refracted by the objective lens system 110, and projected onto the fundus Ef. The measured light LS is reflected and scattered at various depth positions of the fundus Ef. The return light of the measurement light LS including the back-scattered light travels in the opposite direction along the same path and is guided to the fiber coupler 152 and reaches the fiber coupler 153 through the optical fiber f5.

The fiber coupler 153 superimposes the measurement light LS incident through the optical fiber f5 and the reference light LR incident through the optical fiber f3 to generate interference light. FIG. 1 and the like show the case of swept source OCT. The fiber coupler 153 branches the interference light at a predetermined branch ratio (for example, 1: 1) to generate a pair of interference light LCs. The pair of interference light LCs are detected by the detector 155 (balanced photodiode). In the case of spectral domain OCT, the detector 155 (spectrometer) decomposes the interference light generated by the fiber coupler 153 into a plurality of wavelength components and detects them.

The detector 155 sends the result (detection signal) of detecting the pair of interference light LCs to a DAQ (Data Acquisition System) (not shown). A clock is supplied to the DAQ from the OCT light source 151. This clock is generated in synchronization with the output timing of each wavelength swept within a predetermined wavelength range by the tunable light source. The DAQ samples the detection signal based on this clock. The sampling result is sent to the processor for forming the OCT image.

<Processing system>
FIG. 5 shows a configuration example of the processing system of the ophthalmologic imaging apparatus according to the embodiment. The processing system includes a processor for executing various data processing (signal processing, image processing, calculation, control, etc.).

The "processor" includes, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), a programmable logic device (for example, a SPLD (Simple It means a circuit such as Device), FPGA (Field Programmable Gate Array)). The processor realizes the function according to the embodiment by reading and executing a program stored in a storage circuit or a storage device, for example.

<Control unit 200>
The control unit 200 includes a configuration for controlling each unit of the ophthalmologic imaging apparatus. The control unit 200 includes a main control unit 201, a storage unit 202, and a condition determination unit 203. The functions of the main control unit 201 and the condition determination unit 203 are realized by the processor. Various data, various information, and various computer programs are stored in the storage unit 202. The storage unit 202 includes a semiconductor memory and a magnetic storage device.

The processing executed by the ophthalmologic imaging device is realized by the cooperation of hardware resources (processor etc.) and software (computer program etc.). Further, an actuator is provided in at least a part of various mechanisms provided in the ophthalmologic photographing apparatus, and the main control unit 201 sends a control signal to the actuator.

<Main control unit 201>
As an example of control regarding the objective lens system 110, the main control unit 201 controls the angle of view changing mechanism 115 for arranging one of the objective lens units 110A and 110B in the optical path, and controls the objective lens system 110 along the optical axis O. It is possible to control a movement mechanism (not shown) for moving the lens.

As an example of control relating to the SLO optical system 130, the main control unit 201 can execute control of the SLO light source 131, control of the optical scanner 136, control of the detector 135, and control of the variable aperture 139. The control of the SLO light source 131 includes lighting, extinguishing, adjusting the amount of light, adjusting the aperture, and the like. The control of the optical scanner 136 includes a control of a scanning position, a control of a scanning range, a control of a scanning pattern, a control of a scanning speed, and the like. The control of the detector 135 includes exposure adjustment, gain adjustment, detection rate adjustment and the like of the detection element. The control of the variable diaphragm 139 includes changing the size (opening diameter) of the opening, changing the shape of the opening, changing the position of the opening, and the like.

As an example of control regarding the OCT optical system 140, the main control unit 201 executes control of the OCT light source 151, control of the optical scanner 142, movement control of the focusing lens 141, movement control of the reference prism 154, and control of the detector 155. can do. The control of the OCT light source 151 includes lighting, extinguishing, adjusting the amount of light, adjusting the aperture, and the like. The control of the optical scanner 142 includes a control of a scanning position, a control of a scanning range, a control of a scanning pattern, a control of a scanning speed, and the like. The control of the detector 155 includes exposure adjustment, gain adjustment, detection rate adjustment and the like of the detection element.

As an example of control relating to the anterior eye portion photographing system 120, the main control unit 201 can execute control of the anterior eye portion illumination light source 121, control of the anterior eye portion photographing camera 123, and the like. The control of the anterior eye illumination light source 121 includes lighting, extinguishing, adjusting the amount of light, adjusting the aperture, and the like. The control of the front eye photographing camera 123 includes exposure adjustment, gain adjustment, imaging rate adjustment, and the like of the image pickup device.

An example of control relating to the optical system 100 is control of the optical system moving mechanism 100A for moving the optical system 100 in the X direction, the Y direction, and the Z direction.

<Memory unit 202>
The storage unit 202 stores correspondence information indicating the correspondence between the angle of view and the beam size. The correspondence information is referred to by the condition determination unit 203 to determine the beam size from the specified angle of view. Correspondence information can also be used to determine the angle of view from the specified beam size. Correspondence information is arbitrary information representing the correspondence between the angle of view (or information related thereto) and the beam size (or information related thereto), and is, for example, a table or a graph.

The correspondence information may include the value of the angle of view. As a typical example, the angle of view value α1 (for example, 100 degrees) when the objective lens unit 110A is used and the angle of view value α2 (for example, 50 degrees) when the objective lens unit 110B is used are set. included. Here, the angle of view α1 corresponds to the angle of view in the wide-angle shooting mode, and the angle of view α2 corresponds to the angle of view in the high-magnification shooting mode.

The information related to the angle of view includes, for example, information that enables the objective lens unit 110A and the objective lens unit 110B to be distinguished from each other. As a typical example thereof, there are identification information given to each of the objective lens units 110A and 110B, and control contents for the angle of view changing mechanism 115.

Correspondence information may include beam size values. As a typical example, a beam diameter D1 applied when the objective lens unit 110A is used and a beam diameter D2 applied when the objective lens unit 110B is used are included. Here, the beam diameter D1 corresponds to the beam diameter in the wide-angle shooting mode, and the beam diameter D2 corresponds to the beam diameter in the high magnification shooting mode. Generally, the beam diameter D1 for wide-angle photography is smaller than the beam diameter D2 for high-magnification photography (that is, α1> α2 and D1 <D2).

The information related to the beam size includes information on the variable diaphragm 139 and information on the beam size changing system 143. The information regarding the variable diaphragm 139 includes, for example, information representing the opening size of the variable diaphragm 139, or control content for the variable diaphragm 139. The information regarding the beam size changing system 143 includes, for example, information that enables the collimating lens 143A and the collimating lens 143B to be distinguished from each other. As a typical example thereof, there are identifications given to the collimating lenses 143A and 143B, and control contents for the beam diameter changing mechanism 143C.

The storage unit 202 may store a plurality of correspondence information. Multiple correspondence information is used selectively or in combination. For example, correspondence information can be provided for each shooting modality. Alternatively, correspondence information can be provided for each wavelength of the light beam used for photographing (for each wavelength band). In an exemplary embodiment, a light beam with a center wavelength of 840 nm is used for SLO and a light beam with a center wavelength of 1050 nm is used for OCT. Further, the corresponding information regarding the wavelength band having a central wavelength of 840 nm and the corresponding information regarding the wavelength band having a central wavelength of 1050 nm are stored. The condition determination unit 203 refers to the former to control the beam size of the SLO light and the latter to control the beam size of the OCT light.

Some examples of correspondence information are described below. The first correspondence information is created based on the angle of view, resolution, and the like. The second correspondence information is created based on the aberration of the optical system 100, the aberration of the human eye (eye optical system), and the like. The third correspondence information is created based on the depth of focus of the optical system 100 and the like. The correspondence information is not limited to these, and correspondence information created based on a desired parameter, a desired theory, a desired simulation, or the like can be used.

The first correspondence information based on the angle of view, the resolution, etc. will be described. Let P be the number of pixels in the lateral direction (X direction, Y direction) of a general scanning fundus photography device. The number of pixels P is, for example, about 2000. The number of pixels P is defined as, for example, the number of scan positions (illumination points of light beams) in the lateral direction, or the number of pixels of an image based on the data collected by scanning. On the other hand, the angle of view is selected by the user or the device at the time of shooting.

Assuming that the angle of view is α [rad], the required resolution is α / P. Considering that the optical resolution is expressed as 1.22λ / D [rad] (λ: wavelength, D: beam diameter) and the wavelength λ is determined by the configuration of the optical system, the optimum beam diameter D is determined. A value that satisfies the following equation: α / P = 1.22λ / D. For example, when the number of pixels P = 2000 and the wavelength λ = 600 nm, D1 = 0.84 mm is obtained as the optimum beam diameter corresponding to the angle of view α1 = 100 degrees in the wide-angle shooting mode, and the angle of view α2 = in the high-magnification shooting mode. D2 = 1.68 mm is obtained as the optimum beam diameter corresponding to 50 degrees.

Examples of the first correspondence information created based on the values thus obtained are shown in FIGS. 6A and 6B. The first correspondence information shown in FIG. 6A is an example of a table showing the correspondence relationship between the angle of view and the beam diameter. The first correspondence information shown in FIG. 6B is an example of a graph showing the correspondence relationship between the angle of view and the beam diameter.

The second correspondence information based on the aberration will be described. In general, in imaging by a scanning fundus photography apparatus, the aberration (device aberration) possessed by the optical system of the apparatus and the aberration (ocular aberration) possessed by the optical system (ocular optical system) of the eye E to be inspected affect. The second correspondence information is created based on at least one of the device aberration and the ocular aberration. The device aberration changes according to the angle of view α applied to the photographing. The device aberration (wavefront aberration) is expressed as Wd (α). On the other hand, the ocular aberration can be considered to be substantially constant if it is on the axis of the eye. Ocular aberration is expressed as We (constant).

When considering only the device aberration, for example, a point image distribution function (PSF) is calculated based on Wd (α), the width of this point image distribution function is obtained, and this is set as the optimum beam diameter. When considering only ocular aberration, for example, a point image distribution function is calculated based on We, the width of this point image distribution function is obtained, and this is set as the optimum beam diameter. When both device aberration and ocular aberration are considered, the point image distribution function is calculated based on the sum W = Wd (α) + We of the device aberration and the ocular aberration, and the width of this point image distribution function is obtained. The optimum beam diameter is used. The method of calculating the point image distribution function from the wave surface aberration is, for example, the operation of obtaining the pupil function from the wave surface aberration, the operation of Fourier transforming this pupil function, and the function obtained by this Fourier transform, as in the conventional case. Includes an operation to find the square of the absolute value of.

By performing the above calculation based on the angle of view α1 in the wide-angle shooting mode, the beam diameter D1 applied in the wide-angle shooting mode can be obtained. Similarly, by performing the above calculation based on the angle of view α2 in the high magnification shooting mode, the beam diameter D2 applied in the high magnification shooting mode can be obtained. Then, a table similar to that shown in FIG. 6A can be created and used as the second correspondence information. Further, for example, by performing the above calculation based on various values of the angle of view, a graph similar to that in FIG. 6B can be created and used as the second correspondence information.

The third correspondence information based on the depth of focus and the like will be described. In general, the depth of focus DEPTH of the optical system of the scanning fundus photography device is obtained by the following equation: DEPTH = λ / (2NA ^ 2) = λ / (D / 2f). Here, λ represents a wavelength, NA represents a numerical aperture, D represents a beam diameter, and f represents a focal length. In the case of the human eye, the focal length f is about 17 mm (in terms of air). Therefore, as the beam diameter D becomes smaller, the depth of focus DEPTH increases.

See FIG. 7 here. The optical axis of the eye E to be inspected is indicated by the reference numeral EA, and the surface (a set of focusing points) on which the scanned light beam is focused is indicated by the reference numeral F. Further, the scan center is indicated by the reference numeral C0, and the intersection of the optical axis EA and the fundus Ef is indicated by the reference numeral C1. In this example, the center point of the condensing surface F coincides with the intersection point C1. That is, the scan angle θ is defined with the optical axis EA as a reference (0 degree). Further, the distance between the scan center C0 and the intersection C1 is the scan radius R. The light collecting surface F is a part of a spherical surface having a scan center C0 as a center and a scan radius R as a radius. The scan radius R is a constant determined by the optical characteristics of the device and the optical characteristics of the eye to be inspected.

The intersection of the path of the light beam and the condensing surface F when the scan angle is θ is indicated by reference numeral C2. The distance between the scan center C0 and the intersection C2 is the scan radius R. Further, the intersection of the path of the light beam and the fundus Ef (retina surface) when the scan angle is θ is indicated by the reference numeral C3. Although there are individual differences, the shape of the retina is generally an ellipsoidal shape. Therefore, the intersection C2 and the intersection C3 do not match. The distance between the scan center C0 and the intersection C3 depends on the scan angle θ, which is indicated by Re (θ). The distance between the intersection C2 and the intersection C3 also depends on the scan angle θ, which is indicated by ΔR (θ). Therefore, Re (θ) = R + ΔR (θ) holds for any scan angle θ.

As can be seen from the above relationship and FIG. 7, the following equation holds for any scan angle θ. : {(ΔR (θ) + R) sinθ} ^ 2 + {(Re (θ) -R) sinθ} ^ 2 = Re (θ) ^ 2. By substituting the respective values of the scan angle θ, the scan radius R, and the distance Re (θ) into this equation, ΔR (θ) can be obtained. Since the angle of view α is twice the scan angle θ, for example, the beam diameter D can be obtained by the following equation: ΔR (θ) = λ / (D / 2 × 17). Here, the wavelength λ is known, and ΔR (θ) can be obtained by the above calculation.

By performing the above calculation based on θ1, which is a value of 1/2 of the angle of view α1 in the wide-angle shooting mode, the beam diameter D1 applied in the wide-angle shooting mode can be obtained. Similarly, by performing the above calculation based on θ2, which is a value of 1/2 of the angle of view α2 in the high magnification shooting mode, the beam diameter D2 applied in the high magnification shooting mode can be obtained. Then, a table similar to that shown in FIG. 6A can be created and used as the third correspondence information. Further, for example, by performing the above calculation based on various values of the angle of view, a graph similar to that in FIG. 6B can be created and used as the third correspondence information.

The correspondence information may include information on the amount of light in addition to the correspondence between the angle of view and the beam diameter. For example, it is considered desirable to scan the eye E to be inspected with a light beam having substantially the same amount of light (intensity) before and after switching the photographing mode. It is possible to set the value of the parameter for realizing such light amount adjustment for each shooting mode (for each angle of view) and include them in the corresponding information.

Such light amount adjustment is particularly effective when the beam size is changed by blocking a part of the light beam. In this embodiment, the light intensity adjustment can be applied to the SLO optical system 130 using the variable aperture 139. The change in the amount of light is realized, for example, by changing the amount of output light of the SLO light source 131. The value of the output light amount for each shooting mode can be calculated based on the amount of light blocked by the variable aperture 139 (or the same amount of light that passes through the aperture of the variable aperture 139). By calculating the value L1 of the output light amount in the wide-angle shooting mode and the value L2 of the output light amount in the high-magnification shooting mode, the corresponding information as shown in FIG. 8 can be obtained. In general, the beam diameter D1 for wide-angle shooting with an angle of view α1 is smaller than the beam diameter D2 for high-magnification shooting with an angle of view α2, so the output light amount L1 is set to be larger than the output light amount L2 (that is, α1> α2, D1). <D2 and L1> L2).

<Condition determination unit 203>
The condition determination unit 203 sets the imaging conditions according to the angle of view specified by the user (examiner) or the ophthalmologic imaging apparatus 1. The shooting conditions include at least the beam diameter (beam size). The angle of view can be specified, for example, by selecting from a plurality of options regarding the angle of view (eg, angle of view α1, angle of view α2, etc.), or by selecting multiple options regarding the shooting mode (eg, wide-angle shooting mode, high-magnification shooting mode, etc.). It is done by choosing from. The angle of view designation result is input to the condition determination unit 203.

The condition determination unit 203 selects the beam diameter corresponding to the designated angle of view from the corresponding information. For example, when the first correspondence information (table) shown in FIG. 6A is referred to and the angle of view α1 (or α2) is specified, the condition determination unit 203 uses the beam corresponding to the angle of view α1 (or α2). Select the diameter D1 (or D2). When the angle of view α is specified when the first correspondence information (graph) shown in FIG. 6B is referred to, the condition determination unit 203 specifies the coordinates of the horizontal axis corresponding to the angle of view α, and uses these coordinates. Specify the coordinates of the corresponding vertical axis. The beam diameter D indicated by the value on the vertical axis is used as the beam diameter corresponding to the angle of view α.

When the correspondence information shown in FIG. 8 is referred to, the condition determination unit 203 determines the beam diameter and the amount of light corresponding to the designated angle of view. For example, when the angle of view α1 (or α2) is specified, the condition determination unit 203 selects the beam diameter D1 (or D2) and the light intensity L1 (or L2) corresponding to the angle of view α1 (or α2).

Further, it is possible to control the light source (SLO light source 131 or the like) so as to perform scanning with the amount of light set by the user or the ophthalmologic photographing apparatus 1. When shooting at different angles of view after the light intensity is set, the first shooting (first angle of view) is executed with the set first light intensity, and the setting is based on the first light intensity and the corresponding information. The next shooting (second angle of view) can be performed with the second amount of light.

For example, when the corresponding information shown in FIG. 8 is applied, when shooting in the wide-angle shooting mode (angle of view α1) is executed, and then shooting in the high-magnification shooting mode (angle of view α2) is executed, the amount of light L1 The second light amount can be obtained by changing the first light amount based on the ratio (or difference, etc.) between the light amount and the light amount L2. Alternatively, the second light amount can be obtained by changing the first light amount based on the ratio (or difference, etc.) between the beam diameter D1 and the beam diameter D2 by utilizing the fact that the light amount is set based on the beam diameter.

<Image forming unit 210>
The image forming unit 210 forms an image of the fundus Ef based on the data collected by the optical system 100. Since the ophthalmologic imaging apparatus 1 can perform both SLO and OCT, the image forming unit 210 includes an SLO image forming unit 211 and an OCT image forming unit 212.

The SLO image forming unit 211 forms an SLO image based on the data collected by the SLO optical system 130. More specifically, the SLO image forming unit 211 forms an SLO image based on the detection signal input from the detector 135 and the pixel position signal input from the control unit 200, as in the conventional SLO. do.

The OCT image forming unit 212 forms an OCT image based on the data collected by the OCT optical system 140. More specifically, the OCT image forming unit 212 forms an OCT image based on the detection signal input from the detector 155 and the pixel position signal input from the control unit 200. The OCT image forming unit 212 generates a spectral distribution from the output from the detector 155 for each series of wavelength scans (for each A line) as in the conventional case, and performs Fourier transform or the like on the spectral distribution. Thereby, the reflection intensity profile in each A line is obtained. Further, the OCT image forming unit 212 forms a cross-sectional image (B scan image) by imaging the reflection intensity profile of each A line.

The OCT image forming unit 212 can form a three-dimensional image (three-dimensional data set such as stack data and volume data) based on a plurality of B-scan images. Further, the OCT image forming unit 212 can form a display image by rendering a three-dimensional data set.

The image forming unit 210 can form an anterior eye part image based on the output from the anterior eye part photographing camera 123. Various images (image data) formed by the image forming unit 210 are stored in, for example, a storage unit 202.

<Data processing unit 220>
The data processing unit 220 executes various data processing. As an example of data processing, there is processing for image data formed by the image forming unit 210 or another device. Examples of this processing include various image processing, analysis processing for images, and diagnostic support processing such as image evaluation based on image data.

<User interface section 230>
The user interface (UI) unit 230 has a function for exchanging information between the user and the ophthalmologic photographing apparatus. The UI unit 230 includes a display device and an operation device (input device). Display devices include, for example, a liquid crystal display (LCD). The operating device includes various hardware keys and / or software keys. The control unit 200 receives the operation content for the operation device and outputs a control signal corresponding to the operation content to each unit. It is possible to integrally configure at least a part of the operating device and at least a part of the display device. The touch panel display is one example.

<Operation>
An example of the operation of the ophthalmologic imaging apparatus according to the embodiment will be described.

(S1: Set the amount of light)
First, preparations for shooting are made. In this example, the amount of light of the light beam for scanning the fundus Ef is set. The setting of the light amount is executed by using the hardware key provided in the UI unit 230 or by using the software key displayed on the UI unit 230 (display device) by the main control unit 201. It is also possible to set the amount of light automatically. For example, the amount of light applied in the past shooting is applied again.

When multiple modality is used, the amount of light can be set for each modality. In this example, the amount of light for SLO (the amount of output light of the SLO light source 131) and the amount of light for OCT (the amount of output light of the OCT light source 151) can be set respectively.

The amount of light is set, for example, by setting (selecting, specifying, etc.) the value of the amount of light. Alternatively, the desired one may be selected from a plurality of options (eg, high, medium, low) indicating the degree of light intensity.

(S2: Execution of alignment)
Alignment can be performed with reference to the anterior segment image obtained by the anterior segment imaging system 120. The alignment includes, for example, XY alignment in which the optical axis O of the optical system 100 coincides with the center of the pupil of the eye E to be inspected, and Z for arranging the optical system 100 at a position separated from the eye E to be inspected by a predetermined distance (working distance). Includes alignment and. Alignment is an auto alignment or a manual alignment performed by a known method. After the alignment is completed, focusing, OCT optical path length adjustment, polarization state adjustment, and the like may be performed.

(S3: Select the angle of view)
Next, the user or the main control unit 201 selects the angle of view. For example, the angle of view can be selected by selecting the shooting mode. The main control unit 201 controls the angle of view changing mechanism 115 so as to arrange the objective lens unit corresponding to the selected shooting mode in the optical path. In another example, the user can select an objective lens unit corresponding to the desired shooting mode and manually place it in the optical path. In this case, the type of the objective lens unit arranged in the optical path is detected by the above-mentioned type detection unit. Thereby, the shooting mode selected by the user can be specified. In this example, the wide-angle shooting mode is selected at this stage, and the objective lens unit 110A corresponding to this is arranged in the optical path.

(S4: Determine the beam diameter)
The condition determination unit 203 determines the beam diameter according to the angle of view (shooting mode) selected in step S3 by referring to the correspondence information.

(S5: Control the variable aperture)
The main control unit 201 controls the variable diaphragm 139 of the SLO optical system 130 based on the beam diameter determined in step S4. As a result, the beam diameter of the SLO light is adjusted to a size corresponding to the wide-angle shooting mode.

(S6: Control the collimating lens)
Further, the main control unit 201 controls the beam diameter changing mechanism 143C of the OCT optical system 140 based on the beam diameter determined in step S4, thereby arranging the collimating lens 143A corresponding to the wide-angle photographing mode in the optical path. As a result, the beam diameter of the OCT light is adjusted to a size corresponding to the wide-angle shooting mode. It should be noted that the control of the beam diameter changing mechanism 143C may be executed before the control of the variable diaphragm 139, or these controls may be performed in parallel.

(S7: Control the amount of light)
The main control unit 201 sets the output light amount of at least one of the SLO light source 131 and the OCT light source 151 based on the light amount set in step S1.

(S8: Execute SLO / OCT)
The main control unit 201 executes at least one of SLO and OCT of the fundus Ef based on the above conditions. For example, one of SLO and OCT is executed, and then the other is executed. Alternatively, SLO and OCT are performed in parallel.

In this example, both SLO and OCT are executed in the wide-angle shooting mode. The wide-angle SLO is performed by the SLO optical system 130. The SLO image forming unit 211 forms a wide-angle SLO image of the fundus Ef based on the data collected by the SLO optical system 130. On the other hand, wide-angle OCT is performed by the OCT optical system 140. The OCT image forming unit 212 forms a wide-angle OCT image (three-dimensional image) of the fundus Ef based on the data collected by the OCT optical system 140.

(S9: Display the image)
The main control unit 201 stores the wide-angle SLO image and the wide-angle OCT image acquired in step S8 in the storage unit 202, and displays these wide-angle images on the display device of the UI unit 230. The display mode at this time is arbitrary.

(S10: Do you want to change the angle of view?)
By observing the image displayed in step S9, the user can determine whether or not to perform further shooting by changing the angle of view. For example, if an SLO image or an OCT image acquired in the wide-angle imaging mode is observed and a wide range of screening is performed, and a region to be observed in more detail is found, it is possible to shift to high-magnification imaging of that region.

When no further photographing is performed (S10: No), the process proceeds to step S11. On the other hand, when further photographing is performed by changing the angle of view (S10: Yes), the process returns to step S3.

In this example, high-magnification shooting is performed following wide-angle shooting. In step S3, the objective lens unit 110B corresponding to the high magnification photographing mode is arranged in the optical path. In step S4, the condition determination unit 203 obtains a beam diameter corresponding to the high magnification photographing mode by referring to the corresponding information. In step S5, the main control unit 201 controls the variable aperture 139 of the SLO optical system 130 and the beam diameter changing mechanism 143C of the OCT optical system 140 based on the beam diameter of the high magnification imaging mode. As a result, the beam diameters of both the SLO light and the OCT light are adjusted to the size corresponding to the high magnification shooting mode. In step S7, the main control unit 201 sets the output light amount of at least one of the SLO light source 131 and the OCT light source 151 based on the light amount set in step S1 and the corresponding information (ratio of light amount, etc.). In step S8, the main control unit 201 executes at least one of SLO and OCT of the fundus Ef based on the changed conditions. In this example, both SLO and OCT are executed in the high magnification imaging mode, and a high magnification SLO image and a high magnification OCT image are formed. In step S9, the main control unit 201 stores the high-magnification SLO image and the high-magnification OCT image in the storage unit 202, and causes the display device of the UI unit 230 to display these high-magnification images.

When further photographing is performed by changing the angle of view (S10: Yes), the process returns to step S3, and the above-mentioned series of processes is repeatedly executed. On the other hand, when further photographing is not performed (S10: No), the process proceeds to step S11.

(S11: Save the image)
When the shooting is completed (S10: No), the main control unit 201 controls the communication interface (not shown) to obtain the images (wide-angle SLO image, wide-angle OCT image, high-magnification SLO image, high-magnification OCT image) acquired in the above-mentioned shooting. Etc.) to the image arcumbing device. This completes the process related to this example (end).

<Modification example>
A modified example of the above embodiment will be described. Unless otherwise specified, the drawings and explanations of the above embodiments will be referred to. Further, it is possible to combine the above embodiment with any one or more of the following modifications, or to combine any two or more of the following modifications. It is also possible to combine any known technique with such a combination.

(First modification)
In the above embodiment, the beam size is determined with reference to the correspondence information created in advance. On the other hand, in this modification, the data obtained by actually measuring the eye E to be inspected is reflected in the determination of the beam size. Therefore, the storage unit 202 stores the measurement information obtained by measuring the eye E to be inspected. The measurement of the eye E to be inspected is performed by the ophthalmologic imaging device 1 or by another ophthalmologic device. When the eye E to be inspected is measured by another ophthalmologic apparatus, the measurement information is input to the ophthalmologic imaging apparatus 1. The condition determination unit 203 calculates the beam size based on the angle of view (or shooting mode) selected by the user or the like and the measurement information.

The first example will be described. The storage unit 202 stores in advance the aberration information of the SLO optical system 130 and the aberration information of the OCT optical system 140 for each applicable angle of view. For example, as aberration information of the SLO optical system 130, aberration information in a state where the objective lens unit 110A is arranged in the optical path and aberration information in a state where the objective lens unit 110B is arranged in the optical path are provided. Similarly, as aberration information of the OCT optical system 140, aberration information in a state where the objective lens unit 110A is arranged in the optical path and aberration information in a state where the objective lens unit 110B is arranged in the optical path are provided.

The measurement information of the first example includes aberration information of the eye E to be inspected. That is, in the first example, the aberration information of the eye E to be inspected is measured, and the result is stored in the storage unit 202. The aberration information includes, for example, any of various aberrations such as spherical aberration, coma, astigmatism, curvature of field, distortion, and chromatic aberration. For the measurement of the aberration of the eye to be inspected E, for example, an eye aberration measuring device using a Shack-Hartmann wavefront sensor (see JP-A-2007-252402, etc.) and a corneal shape analysis device for acquiring corneal topography (special table). 2003-530173, etc.).

The condition determination unit 203 acquires aberration information corresponding to the angle of view (shooting mode) selected by the user or the like from the storage unit 202. For example, when the wide-angle shooting mode is selected, the condition determination unit 203 determines the aberration information of the SLO optical system 130 in the state where the objective lens unit 110A is arranged in the optical path, and the OCT in the state where the objective lens unit 110A is arranged in the optical path. The aberration information of the optical system 140 is read from the storage unit 202.

Next, the condition determination unit 203 calculates a point image distribution function based on the aberration information acquired from the storage unit 202 and the aberration information of the eye E to be inspected, and the beam size (beam diameter) is calculated based on this point image distribution function. ) Is calculated. This arithmetic processing is executed, for example, in the same manner as the arithmetic for creating the second correspondence information of the above embodiment.

The main control unit 201 controls the variable aperture 139 based on the beam diameter calculated using the aberration information of the SLO optical system 130, and is based on the beam diameter calculated using the aberration information of the OCT optical system 140. Controls the beam diameter changing mechanism 143C.

A second example will be described. The storage unit 202 stores in advance the scan radius of the optical system 100 and the focal length of the human eye (focal length of the eye). The focal length of the eye may be a standard value or a value obtained by measuring the eye E to be inspected. The scan radius is a design value of the optical system 100. The storage unit 202 may store the scan radius of the SLO optical system 100 and the scan radius of the OCT optical system 140, respectively.

The measurement information of the second example includes the axial length information of the eye E to be inspected. That is, in the second example, the axial length of the eye to be inspected E is measured, and the result is stored in the storage unit 202. As a method for measuring the axial length of the eye to be inspected E, a method using OCT and a method using ultrasonic waves are well known.

The condition determination unit 203 calculates the depth of focus based on the angle of view (shooting mode) selected by the user or the like, the axial length information, and the scan radius, and is based on the depth of focus, the wavelength of the light beam, and the focal length of the eye. And calculate the beam size (beam diameter). Here, the axial length information is used to calculate (approximate) the radius of curvature of the fundus. This arithmetic processing is executed, for example, in the same manner as the arithmetic for creating the third correspondence information of the above embodiment.

The main control unit 201 controls the variable aperture 139 based on the beam diameter calculated using the scan radius of the SLO optical system 130, and is based on the beam diameter calculated using the scan radius of the OCT optical system 140. Controls the beam diameter changing mechanism 143C.

(Second modification)
In the above embodiment, the beam size is determined with reference to the correspondence information created in advance. On the other hand, in the first modification, the data obtained by actually measuring the eye E to be inspected is reflected in the determination of the beam size. On the other hand, in this modification, a configuration will be described in which an image of the eye E to be inspected is actually acquired, the image quality is evaluated, and a beam size is searched for so as to obtain a suitable image quality. That is, in this modification, the evaluation of the image quality of the image is fed back to adjust the beam size.

FIG. 10 shows an example of the configuration of the ophthalmologic imaging apparatus according to this modification. The ophthalmologic imaging apparatus according to this modification is different from the configuration of the above embodiment (see FIG. 5) in that it includes an image quality evaluation unit 221. The image quality evaluation unit 221 is provided in the data processing unit 220. The image quality evaluation unit 221 analyzes the image formed by the image forming unit 210 and calculates the evaluation value of the image quality.

The evaluation value of the image quality includes, for example, a value obtained by quantifying the contrast of the image. Contrast assessment is performed by known techniques and involves, for example, the calculation of noise level or noise quality. The noise level is obtained, for example, by calculating the variation (standard deviation) from the average value, and it is determined that the larger the value, the more noise there is. The noise quality is obtained, for example, by calculating the noise power spectrum, and it is determined that the larger the value, the worse the noise quality. This enables qualitative evaluation of frequency characteristics and the like. The image quality evaluation method is not limited to these, and for example, a signal noise ratio or a contrast noise ratio can be used. In another example, the evaluation value of the image quality can be calculated by using the process of detecting the edge of the image. Edge detection is performed by a known method. It is also possible to use image quality parameters different from those of contrast and edge.

The main control unit 201 of this modification controls the variable aperture 139 and / or the beam diameter changing mechanism 143C based on the evaluation value calculated by the image quality evaluation unit 221.

The operation related to this modification will be described. When the shooting mode (angle of view) is changed, the main control unit 201 controls the optical system 100 (for example, the SLO optical system 130) to repeatedly execute scanning at the new angle of view. The SLO image forming unit 211 forms an SLO image of the angle of view based on the data collected in each scan. This process is repeated in synchronization with the repeated scans. The SLO images sequentially formed by the SLO image forming unit 211 are sequentially sent to the image quality evaluation unit 221 via the main control unit 201. The image quality evaluation unit 221 calculates an evaluation value of the image quality of each SLO image.

At a predetermined stage, the main control unit 201 controls the variable diaphragm 139 to change the beam diameter of the SLO light. At this time, the beam diameter may be increased or decreased. Further, the expansion and reduction of the beam diameter may be performed in any order. Further, the amount of change in the beam diameter may be a predetermined amount. Alternatively, the amount of change in the beam diameter may be determined based on the magnitude of the evaluation value of the image quality of the currently obtained SLO image.

The image quality evaluation unit 221 calculates, for example, an evaluation value of the image quality of the SLO image based on the data obtained by scanning using SLO light having an enlarged beam diameter. The main control unit 201 compares the evaluation value of the SLO image acquired before the expansion of the beam diameter with the evaluation value of the SLO image acquired after the expansion. When the image quality is improved by expanding the beam diameter, the main control unit 201 controls, for example, the variable diaphragm 139 so as to further expand the beam diameter (by a predetermined amount). Then, the evaluation value of the image quality of the SLO image obtained after the further change of the beam diameter is compared with the evaluation value of the image quality of the SLO image obtained before that.

On the other hand, when the image quality deteriorates due to the expansion of the beam diameter, the main control unit 201 controls the variable diaphragm 139 so as to reduce the beam diameter (by a predetermined amount), for example. Then, the evaluation value of the image quality of the SLO image obtained after the reduction of the beam diameter is compared with the evaluation value of the image quality of the SLO image obtained before that.

By repeating the series of processes (scanning, image formation, image quality evaluation, beam diameter change, etc.) as described above, it is possible to search for the beam diameter that maximizes the evaluation value. That is, by repeating such a series of processes, the optimum value of the beam diameter after changing the angle of view can be obtained. Alternatively, the above series of processes may be repeated until the evaluation value reaches a preset threshold value.

For OCT, the same series of processing (scanning by the OCT optical system 140, OCT image formation (OCT image forming unit 212), image quality evaluation (image quality evaluation unit 221), control of beam diameter changing mechanism 143C, etc.) is performed. By doing so, the beam diameter of the OCT light can be optimized.

(Third modification example)
In the above embodiment, the angle of view is changed by selectively applying the objective lens units 110A and 110B, but the present invention is not limited to this. For example, the angle of view can be changed by changing the deflection angle of the light beam by the optical deflector (the range of operation, that is, the range in which the direction of the reflecting surface is tilted). The change of the angle of view of the SLO scan (SLO image) is realized by changing the deflection angle of the optical scanner 136 of the SLO optical system 130. Further, the change of the angle of view of the OCT scan (OCT image) is realized by changing the deflection angle of the optical scanner 142 of the OCT optical system 140. As described above, the control of the optical scanners 136 and 142 is executed by the main control unit 201.

(Fourth modification)
In the above embodiment, the case where the ophthalmologic photographing apparatus performs an operation for changing the angle of view (insertion of the objective lens unit 110A or 110B into the optical path) has been described in particular detail. On the other hand, in this modification, a case where the user (inspector) performs an operation for changing the angle of view will be described.

FIG. 11 shows an example of the configuration of the ophthalmologic imaging apparatus according to this modification. The ophthalmologic imaging apparatus according to this modification is different from the configuration of the above embodiment (see FIG. 5) in that it includes an angle of view detection unit 116. In this modification, the angle of view changing mechanism 115 may or may not be provided. Further, in the example shown in FIG. 11, the angle of view detection unit 116 is provided in the objective lens system 110, but the installation location is not limited to this.

In this modification, the user arranges the objective lens unit 110A or 110B corresponding to the desired angle of view in the optical path. The angle of view detection unit 116 detects whether the objective lens unit arranged in the optical path is the objective lens unit 110A or 110B. An example of the configuration for that purpose will be described. Convex portions are formed at different positions in the objective lens units 110A and 110B, respectively. Further, the angle of view detection unit 116 includes a first microswitch that abuts on the convex portion of the objective lens unit 110A arranged in the optical path and a first microswitch that abuts on the convex portion of the objective lens unit 110B arranged in the optical path. including. Each micro switch sends an electric signal to the main control unit 201 when it comes into contact with the convex portion. Thereby, the ophthalmologic photographing apparatus (main control unit 201) can recognize which of the objective lens units 110A and 110B is arranged in the optical path. The configuration for detecting which of the objective lens units 110A and 110B is arranged in the optical path is not limited to this.

When a configuration for changing the angle of view by changing the deflection angles of the optical scanners 136 and 142 is applied as in the third modification, the user specifies a desired angle of view using, for example, the UI unit 230. .. In this case, the main control unit 201 can recognize the designated angle of view based on the operation signal input from the UI unit 230.

The main control unit 201 controls the variable aperture 139 and / or the beam diameter changing mechanism 143C based on the detection result by the angle of view detection unit 116. In order to perform this control, the condition determination unit 203, for example, based on the detection result (angle of view) by the angle of view detection unit 116 and the correspondence information stored in the storage unit 202, the beam corresponding to this angle of view. The diameter can be specified. The process for specifying the beam diameter is not limited to this, and for example, the process according to the first modification can be applied.

<Action / effect>
Some examples of actions and effects that can be provided by the ophthalmologic imaging apparatus according to the embodiment will be described below.

The ophthalmologic imaging apparatus according to the embodiment includes a data acquisition unit, an image forming unit, an angle of view changing unit, a beam size changing unit, and a control unit. The data collection unit scans the fundus of the eye to be inspected using a light beam and collects data. In the above example, the SLO optical system 130 and the OCT optical system 140 correspond to this. The image forming unit forms an image of the fundus based on the data collected by the data collecting unit. In the above example, the SLO image forming unit 211 and the OCT image forming unit 212 correspond to this. The angle of view changing unit includes a configuration for changing the angle of view. In the above example, the objective lens system 110 corresponds to this. Further, optical scanners 136 and 142 (and a main control unit 201 that controls their deflection angles) are also examples. The beam size changing unit changes the size (beam diameter) of the light beam. In the above example, the variable aperture 139 and the beam size change system 143 correspond to this. The control unit controls the angle of view changing unit and the beam size changing unit in a coordinated manner. In the above example, the main control unit 201 corresponds to this.

According to such a configuration, since the angle of view and the beam size can be controlled in a coordinated manner, it is possible to acquire images of various angles of view with appropriate image quality. For example, when the angle of view is changed, the beam size of the light beam can be automatically changed to the beam size according to the new angle of view. On the contrary, when the beam size is changed, the angle of view can be automatically changed according to the new beam size.

The ophthalmologic photographing apparatus according to the embodiment may include an angle of view change instruction unit for inputting an instruction for changing the angle of view to the control unit. The angle of view can be changed electrically (automatically) or manually. In the above example, the objective lens system 110, the UI unit 230, and the like correspond to this. The control unit may include a beam size determination unit that determines the beam size in response to an instruction input from the angle of view change instruction unit. In the above example, the condition determination unit 203 corresponds to this. Further, the control unit is configured to control the angle of view changing unit based on the instruction input from the angle of view changing instruction unit and control the beam size changing unit based on the beam size determined by the beam size determining unit. It may have been done.

According to such a configuration, it is possible to perform shooting (scanning) at an angle of view specified by the user and a beam size corresponding to this angle of view. Further, it is possible to perform scanning with this angle of view and a suitable beam size simply by specifying a desired angle of view by the user.

In the embodiment, the beam size determination unit may include a first storage unit that previously stores correspondence information (table, graph, etc.) representing the correspondence relationship between the angle of view and the beam size. In the above example, the storage unit 202 corresponds to this. Further, the beam size determination unit may be configured to determine the beam size according to the instruction (angle of view) input from the angle of view change instruction unit based on the corresponding information.

According to such a configuration, it is possible to control the angle of view and the beam size in a coordinated manner with reference to a suitable correspondence between the angle of view and the beam size set in advance.

In embodiments, the data acquisition unit may be capable of performing scans with light beams of different wavelengths. In the above example, SLO and OCT can be performed at different wavelengths. Further, it is possible to configure SLO to be executed at two or more different wavelengths, or to execute OCT at two or more different wavelengths. The first storage unit may store corresponding information regarding each of the plurality of wavelengths. The beam size determination unit may be configured to determine the beam size based on the corresponding information according to the wavelength of the light beam used by the data acquisition unit.

According to such a configuration, it is possible to perform linked control of the angle of view and the beam size according to the wavelength of the light beam used for scanning.

In the embodiment, the configuration of the corresponding information is arbitrary. For example, the correspondence information may include the first correspondence information created based on the relationship between the angle of view, the number of pixels, the wavelength, and the beam size. Further, the correspondence information may include the second correspondence information created based on the point image distribution function calculated from at least one of the aberration of the optical system and the aberration of the ocular optical system included in the data acquisition unit. Further, the correspondence information may include a third correspondence information created based on the relationship between the depth of focus, the wavelength, the focal length of the ocular optical system, and the beam size. When two or more types of correspondence information are provided, these can be selectively used. The selection of correspondence information is done manually or automatically. When the correspondence information is automatically selected, for example, the correspondence information used in the past shooting is selected. Alternatively, the corresponding information can be selected based on the subject's attributes (gender, age, medical history, etc.) and disease type.

In the embodiment, the beam sizing unit may include a second storage unit that stores the measurement information obtained by measuring the eye to be inspected. In the above example, the storage unit 202 corresponds to this. The measurement information is created by the ophthalmologic imaging device or other ophthalmologic device. Further, the beam size determination unit may be configured to calculate the beam size based on the instruction (angle of view) input from the angle of view change instruction unit and the measurement information.

For example, the second storage unit may store the aberration information of the optical system included in the data acquisition unit in advance for each of the plurality of angles of view. Further, the measurement information may include aberration information of the eye to be inspected. The beam size determination unit acquires aberration information corresponding to the instruction input from the angle of view change instruction unit from the second storage unit, and obtains a point image distribution function based on the acquired aberration information and the aberration information of the eye to be inspected. It may be configured to calculate and calculate the beam size based on the point spread function.

In another example, the second storage unit may store in advance the radius of the scan by the data acquisition unit and the focal length of the eye. Further, the measurement information may include information on the axial length of the eye to be inspected. The beam size determination unit calculates the depth of focus based on the angle of view indicated by the instruction input from the angle of view change instruction unit, the axial length information, and the scan radius, and the calculated focal length and the wavelength of the light beam are used. It may be configured to calculate the beam size based on the focal length of the eye.

It is possible to selectively apply a plurality of calculation methods in order to calculate the beam size. The selection of the calculation method is executed, for example, based on the type of information included in the measurement information of the eye to be inspected. As a specific example, the former example can be selected when the measurement information includes aberration information, and the latter example can be selected when the measurement information includes axial length information.

According to such a configuration, it is possible to control the angle of view and the beam size in a coordinated manner by using the data obtained by actually measuring the eye to be inspected.

The ophthalmologic photographing apparatus according to the embodiment may include an image quality evaluation unit that analyzes an image formed by the image forming unit and calculates an evaluation value of image quality. In the above example, the image quality evaluation unit 221 corresponds to this. The control unit may be configured to control the beam size change unit based on the evaluation value calculated by the image quality evaluation unit.

With such a configuration, it is possible to search for the optimum beam size while referring to the actually acquired image.

In the embodiment, the angle of view changing unit may include two or more objective lenses that can be selectively arranged in the optical path of the light beam. Alternatively or additionally, the angle of view changing section may include a light deflector with a variable deflection angle for deflecting the light beam. In the above example, the objective lens units 110A and 110B correspond to two or more objective lenses. Further, the optical scanners 136 and 142 correspond to the optical deflector.

In embodiments, the data acquisition unit may include a light deflector for deflecting the light beam. In the above example, the optical scanners 136 and 142 correspond to this. Further, the beam resizing unit may include two or more lenses that can be selectively arranged at a position closer to the light source that emits the light beam than the light deflector in the optical path of the light beam. In the above example, the collimating lenses 143A and 143B correspond to this.

Also, in embodiments, the data acquisition unit may include a light deflector for deflecting the light beam. In the above example, the optical scanners 136 and 142 correspond to this. Further, the beam resizing unit may include a variable diaphragm arranged at a position closer to the light source that emits the light beam than the light deflector in the optical path of the light beam. In the above example, the variable aperture 139 corresponds to this.

In the embodiment, the control unit may be configured to change the amount of light of the light beam output from the light source when the size of the aperture of the variable diaphragm is changed by the beam size changing unit.

Further, in the embodiment, the control unit reduces the amount of light beam output from the light source when the aperture of the variable diaphragm is expanded, and when the aperture is reduced, the light beam output from the light source. It may be configured to increase the amount of light.

According to such a configuration, the amount of light of the light beam changed by the variable diaphragm can be compensated by controlling the light source. As a result, scanning can be performed with a light beam having a suitable amount of light even if the beam size is changed. For example, scanning can be performed with (almost) the same amount of light beam before and after changing the beam size.

In the embodiment, the control unit may be configured to perform control of the angle of view changing unit, control of the beam size changing unit, and control of the amount of light of the light beam in a coordinated manner.

According to such a configuration, it is possible to automatically control the amount of light of the light beam as well as the coordinated control of the control of the angle of view changing unit and the control of the beam size changing unit.

The ophthalmologic imaging apparatus according to the embodiment includes a data acquisition unit, an image forming unit, an angle of view changing unit, a beam size changing unit, an angle of view detecting unit, and a control unit. The data collection unit scans the fundus of the eye to be inspected using a light beam and collects data. In the above example, the SLO optical system 130 and the OCT optical system 140 correspond to this. The image forming unit forms an image of the fundus based on the data collected by the data collecting unit. In the above example, the SLO image forming unit 211 and the OCT image forming unit 212 correspond to this. The angle of view changing unit includes a configuration for changing the angle of view. In the above example, the objective lens system 110 corresponds to this. Further, optical scanners 136 and 142 (and a main control unit 201 that controls their deflection angles) are also examples. The beam size changing unit changes the size (beam diameter) of the light beam. In the above example, the variable aperture 139 and the beam size change system 143 correspond to this. The angle of view detection unit detects the changed angle of view when the user operates the angle of view changing unit to change the angle of view. In the above example, the angle of view detection unit 116 corresponds to this. The control unit controls the beam size change unit based on the detection result by the angle of view detection unit. In the above example, the main control unit 201 corresponds to this.

According to such a configuration, when the user manually changes the angle of view, the changed angle of view can be detected, and the beam size of the light beam can be automatically changed according to the detection result of this angle of view. It is possible.

The embodiments shown above are merely examples for carrying out the present invention. A person who intends to carry out the present invention can make arbitrary modifications, omissions, additions, etc. within the scope of the gist of the present invention.

100 Optical system 110A, 110B Objective lens unit 115 Angle of view changing mechanism 130 SLO Optical system 136 Optical scanner 139 Variable aperture 140 OCT Optical system 142 Optical scanner 143 Beam size changing system 200 Control unit 211 SLO image forming unit 212 OCT image forming unit

Claims (3)

A data collection unit that scans the fundus of the eye to be inspected using a light beam and collects data.
An image forming unit that forms an image of the fundus based on the data collected by the data collecting unit, and an image forming unit.
An angle-of-view changing unit for changing the angle of view by changing the deflection angle of the light beam by the light deflector, including a light deflector having a variable deflection angle for deflecting the light beam .
A beam size changing unit that changes the size of the light beam,
An ophthalmologic imaging apparatus including a control unit that controls the optical deflector of the angle of view changing unit so as to set an angle of view according to the new beam size when the beam size is changed. The beam size changing unit is characterized by including two or more lenses that can be selectively arranged at a position closer to a light source that emits the light beam than the light deflector in the optical path of the light beam. The ophthalmologic photographing apparatus according to 1. The ophthalmology according to claim 1, wherein the beam size changing unit includes a variable diaphragm arranged at a position closer to a light source that emits the light beam than the light deflector in the optical path of the light beam. Shooting device.

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