JP6958367B2 - Fundus photography device - Google Patents

Description

The present disclosure relates to a fundus photography device for obtaining a frontal image of the fundus.

A fundus camera that captures a frontal image of the fundus of an eye to be inspected is widely used in the field of ophthalmology.

As a kind of fundus photography device, for example, a slit-shaped illumination light is scanned on the fundus, and an image of the illuminated fundus region is sequentially projected onto a two-dimensional imaging surface according to the scanning to obtain a frontal image of the fundus. The device to obtain is known. As a device of this type, in Patent Document 1, a two-hole diaphragm in which two openings are formed along the scanning direction of the slit is arranged on a surface conjugate with the pupil of the projection system to emit illumination light. A device is disclosed in which light is simultaneously irradiated from two openings of a two-hole diaphragm, and light reflected from the fundus of the eye is taken out from a gap of the two-hole diaphragm projected on the pupil to take an image.

Special Publication No. 61-48940

However, in the apparatus of Patent Document 1, when the pupil diameter of the eye to be inspected is small, the image of two openings by the two-hole diaphragm cannot be arranged in the pupil of the eye to be inspected, and the illumination light is vignetting due to the iris. It is possible that the fundus image becomes dark.

The present disclosure has been made in view of the problems of the prior art, and it is a technical subject to provide a fundus photography apparatus that facilitates imaging of an eye to be examined having a smaller pupil diameter.

In the fundus imaging apparatus according to the first aspect of the present disclosure, a light projecting region through which the illumination light passes on the pupil of the eye to be inspected and a light receiving region in which the reflected light from the fundus of the illumination light is taken out on the pupil of the eye to be inspected. The positional relationship between the eye to be inspected and the photographing optical system is that the photographing optical system including the light emitting / receiving separating means formed at different positions and the light receiving element that receives the reflected light from the fundus of the eye taken out from the light receiving region is provided. It is a fundus imaging device that includes a drive unit for adjusting and acquires a fundus image based on a signal from the light receiving element. Two light projection regions are formed, and the entire two light projection regions and the light receiving region are formed in the pupil region of the eye to be inspected as an alignment reference position that serves as a reference for alignment between the eye to be inspected and the imaging optical system. It is assumed that the first reference position and the second reference position are different from the first reference position, and one of the two light projection areas together with the light receiving area has priority over the remaining one light projection area. to a second reference position assumed to be arranged in the pupil of the eye, a one of the possible selectively set to induce alignment based on the alignment deviation from the alignment reference position set At the same time, when the alignment is guided to the first reference position, when the fundus image is taken, the illumination light is projected onto the fundus from both of the two projection regions and aligned to the second reference position. When the fundus image is captured, the imaging control means for projecting the illumination light onto the fundus from only one of the two projection regions preferentially arranged in the pupil is provided. ..
In the fundus imaging apparatus according to the second aspect of the present disclosure, a light projecting region through which the illumination light passes on the pupil of the eye to be inspected and a light receiving region in which the reflected light from the fundus of the illumination light is taken out on the pupil of the eye to be inspected. The positional relationship between the eye to be inspected and the photographing optical system and the photographing optical system including the light receiving and receiving separating means formed at different positions and the light receiving element for receiving the fundus reflected light taken out from the light receiving region. It is a fundus imaging device that includes a drive unit for adjusting and acquires an image of the fundus of the eye based on a signal from the light receiving element. Further, the imaging optical system has a slit-shaped illumination light on the fundus of the eye to be inspected. The slit-forming portion to be formed, a scanning portion for scanning the illumination light formed in the slit shape on the fundus in a direction orthogonal to the slit, and the light-emitting separation means are said to be on the pupil of the eye to be inspected. The light projecting region is formed at two positions separated from each other with respect to the scanning direction of the scanning unit, and the light receiving region is formed so as to be sandwiched between the two light projecting regions on the pupil of the eye to be inspected. As an alignment reference position that serves as a reference for alignment with the imaging optical system, a first reference position assuming that the entire two light projection regions and the light receiving region are formed in the pupil region of the eye to be inspected. It is a second reference position different from the first reference position, and one of the two projection regions together with the light receiving region is arranged in the pupil of the eye to be inspected with priority over the remaining one projection region. It is possible to selectively set any of the second reference position, which is assumed to be the case, and includes an imaging control means that guides the alignment based on the alignment deviation from the set alignment reference position.

It is a figure which showed the mode of irradiating and scanning the illumination light to the fundus by a photographing optical system. It is a figure which showed the light projection area and the light receiving area formed on the pupil of the eye to be examined by the photographing optical system. It is a figure which showed the fundus image which was taken by irradiating the fundus with illumination light at the same time from two light projection regions. It is a figure which showed the fundus image which is taken by irradiating the fundus with illumination light selectively from one of two light projection regions. It is a figure for demonstrating the apparatus structure which can change the clearance between a light-emitting area and a light-receiving area. It is a figure which showed the outline of the process at the time of forming a composite front image in the 1st synthesis method. It is a figure which showed the outline of the process at the time of forming a composite front image in the 2nd synthesis method. It is a figure which shows the method of photographing a small pupil eye by changing the positional relationship between an eye to be inspected and an imaging unit (the imaging optical system). It is a figure which showed the appearance structure of the apparatus which concerns on Example. It is a figure which showed the optical system accommodated in the photographing unit of an Example. It is a figure which showed the optical chopper which can be applied as a scanning part. It is a block diagram which showed the control system of the apparatus which concerns on Example. It is a flowchart which shows the photographing operation of the apparatus. It is a continuous flowchart from FIG. It is a figure which illustrated the display screen of the fundus observation image.

Hereinafter, embodiments of the fundus photography apparatus according to the present disclosure will be described with reference to the drawings. In the following, as the first embodiment, an apparatus in which artifacts caused by reflection / scattering inside the eye to be inspected or the apparatus are suppressed will be disclosed. Further, as a second embodiment, a device capable of satisfactorily capturing a fundus image even when the pupil diameter of the eye to be inspected is small is disclosed. As for each embodiment, a part of other embodiments can be appropriately used.

<First Embodiment>
First, the first embodiment will be described. In the first embodiment, the fundus photography apparatus has at least a photographing optical system (see FIG. 10) and a control unit (see FIG. 12). In addition, the fundus photography apparatus may have an image processing unit.

<Shooting optical system>
The photographing optical system is used to shoot an image of the fundus by projecting and receiving illumination light on the fundus of the eye to be inspected. More specifically, the illumination light is projected so that the illumination light is formed in a slit shape on the fundus of the eye to be inspected. The slit-shaped illumination light is scanned on the fundus. The fundus image is captured with the scanning range as the imaging range.

The photographing optical system has at least a slit forming portion, a scanning portion, and a light emitting / receiving separating portion. In addition, the photographing optical system may include a light source, an image pickup device, an optical path branching portion, and the like.

The slit forming portion forms the illumination light in a slit shape on the fundus of the eye to be inspected. The slit-forming portion may have, for example, a slit-shaped translucent portion (for example, an opening) arranged in a plane conjugate with the fundus.

In the present disclosure, the term "conjugate" is not necessarily limited to a perfect conjugation relationship, but includes "substantially conjugation". That is, the case where the parts are arranged so as to be deviated from the perfect conjugation position within the permissible range in relation to the technical significance of each part is also included in the "conjugation" in the present disclosure.

As shown in FIG. 1, the scanning unit scans the illumination light formed in the shape of a slit on the fundus in a direction intersecting the slit (specifically, a direction intersecting the longitudinal direction of the slit). The scanning unit may scan the illumination light by moving the slit forming portion in a direction intersecting the slit. Examples of this type of scanning unit include mechanical shutters, liquid crystal shutters, optical choppers, drum reels, and the like.

The scanning direction of the slit is preferably a direction orthogonal to the slit. However, it may be oblique to the direction orthogonal to the slit.

Further, the scanning portion may be a member that changes the direction of the light that has passed through the slit forming portion. For example, various optical scanners such as a galvano scanner may be used as a scanning unit. The scanning unit of the type in which light is swirled to perform scanning may be placed at a position conjugate with the pupil of the eye to be inspected.

The photographing optical system may further include an optical path coupling portion and an objective lens.

The optical path coupling portion combines and separates the projected light path of the illumination light and the received light path of the fundus reflected light. The objective lens is arranged on the common optical path of the light projecting light path and the light receiving light path formed by the optical path coupling portion. At this time, it is desirable that the optical axis of the photographing optical system (hereinafter, also referred to as “photographing optical axis”) coincides with the optical axis of the objective lens.

Various beam splitters can be used as optical path couplings. In this case, the optical path coupling portion may be a perforated mirror, a simple mirror, a half mirror, or another beam splitter.

<Separation of light and reception on the pupil of the eye to be inspected>
The light emitting / receiving separation unit separates an area where the illumination light is projected (light projection area) and an area where the fundus reflected light due to the illumination light is extracted (light receiving area) on the pupil of the eye to be inspected.

Specifically, as shown in FIG. 2, the light emitting / receiving separating unit forms the light emitting region at two positions separated from each other with respect to the scanning direction of the illumination light. The two light projection regions may be formed so as to sandwich the photographing optical axis. In the first embodiment, the light emitting / receiving separation unit may be one that forms at least two light emitting regions, and may be one that forms three or more light emitting regions. The illumination light that has passed through each projection region irradiates the same slit-shaped region on the fundus. Then, as the scanning unit is driven, the slit-shaped region is scanned.

As shown in FIG. 2, the light emitting / receiving separating portion is formed so that the light receiving region is sandwiched between the two light emitting regions. That is, each region is formed in a row in the order of one projection region, the light receiving region, and the other projection region. Further, the light receiving region may be formed on the photographing optical axis. The light projecting area and the light receiving area may be arranged so as not to overlap each other. In that case, it is reduced that a part of the illumination light is reflected and scattered in the cornea or the intermediate translucent body to cause flare in the fundus image.

The light emitting / receiving separation unit may include a light emitting path for illumination light and a plurality of members arranged in the light receiving path.

A part of the light emitting / receiving separation unit sets the irradiation position of the illumination light at at least two positions separated from each other with respect to the scanning direction of the illumination light on the pupil conjugate surface in the light projection path of the illumination light. There may be. In this case, light sources that emit illumination light may be arranged at the two irradiation positions, or openings for passing the illumination light may be arranged at the two irradiation positions.

In other words, the light emitting / receiving separation unit includes at least two illumination light sources, or two apparent illumination light sources, which are arranged at positions conjugate with the pupil of the eye to be inspected and at different positions with respect to the scanning direction. There may be. As a result, the projection region is formed at two positions separated from each other with respect to the scanning direction of the illumination light. More preferably, the two illumination sources, or the two apparent illumination sources, may be arranged symmetrically with respect to the imaging optical axis. As a result, the two projection regions can be formed symmetrically with respect to the shooting optical axis. The light projection state from the two light sources or the two apparent light sources may be controllable for each light source by a control unit described later. As a result of controlling the projection state for each light source, whether or not to pass the illumination light is individually set for each projection region. Of course, the light emitting / receiving separation unit may include three or more illumination light sources or three or more apparent illumination light sources.

There can be at least two types of light projection states: a state in which the illumination light from the light source or an apparent light source reaches the eye to be inspected, and a state in which the illumination light does not reach the eye to be inspected. The switching of the flooded state may be realized by the lighting control of the light source. Further, the switching of the light projection state may be realized by driving and controlling a shutter that selectively blocks the light beam from the light source or the apparent light source toward the eye to be inspected.

Further, a part of the light emitting / receiving separation unit allows the reflected light from the fundus of the eye from the light receiving region, which is a region sandwiched between the two light projecting regions, to pass to the imaging surface side on the pupil conjugate surface in the light receiving optical path of the illumination light. , Other light may not pass to the image pickup surface side. For example, the light emitting / receiving separating unit may include a light shielding member that allows the fundus reflected light from the light receiving region to pass toward the imaging surface side and blocks other light. The light-shielding member may be arranged on the pupil conjugate surface in the light receiving optical path, for example. For example, when a diaphragm having an aperture centered on the optical axis of photography is provided as a light-shielding member, a light receiving region is formed by the aperture image of the diaphragm.

When the light emitting / receiving separating portion includes a light-shielding member, the light-shielding member may be shared with the above-mentioned optical path coupling portion or may be a separate body.

<Control unit>
The control unit is a processing device (processor) that performs control processing of each unit and arithmetic processing. For example, the control unit is realized by a CPU (Central Processing Unit), a memory, or the like.

In the first embodiment, the control unit individually sets whether or not to allow the illumination light to pass through the two light projection regions on the pupil of the eye to be inspected. In addition, a fundus image is taken based on the illumination light selectively projected from one (either) of the two projection regions.

By the way, a reflected image (bright spot image, a kind of artifact) may be generated at a position near the photographing optical axis in the fundus image due to the reflection of the illumination light at the center of the lens surface of the objective lens. Since the projection region is far from the shooting optical axis, the reflected image tends to appear at a position slightly deviated from the position of the shooting optical axis in the fundus image. As an example, FIG. 3 shows a fundus image taken by simultaneously projecting illumination light from both of the two projection regions. As shown in FIG. 3, a reflected image can be generated at two locations on the image center of the fundus image with the photographing optical axis in between, corresponding to the two light projection regions. The two reflected images appear side by side in the scanning direction (that is, at different positions with respect to the scanning direction).

On the other hand, in the present embodiment, the fundus image is captured by selectively projecting the illumination light onto the fundus from one of the two projection regions. As a result, in the objective lens, the portion where the reflected image is generated is halved as compared with the above case, so that the reflected image in the fundus image can be halved as shown in FIG. In this way, it is advantageous to selectively project the illumination light to the fundus from one of the two projection areas on the pupil of the eye to be inspected to take the fundus image in order to reduce the artifacts. be.

It should be noted that it is advantageous to photograph the fundus image by selectively projecting the illumination light from one of the two projection regions to the fundus when photographing the eye to be inspected having a small pupil diameter. Even if the pupil diameter is small and the two projection regions cannot be satisfactorily arranged in the pupil region, if the pupil diameter is sufficient to allow the arrangement of one projection region and the light receiving region, a good fundus image can be taken. can.

<Change of clearance between light emitting area and light receiving area>
The light emitting / receiving separation unit may be capable of changing the clearance between the two light emitting regions and the light receiving region on the pupil of the eye to be inspected. The larger the clearance, the less likely it is that a reflected image from the objective lens will occur. If the clearance is small, the light projecting region and the light receiving region are closer to each other, which is advantageous for photographing the small pupil eye.

In this case, for example, when a light source is arranged on the pupil conjugate surface at a position away from the photographing optical axis to form a light projection region on the pupil of the eye to be inspected, a pair of light sources is shown in FIG. As shown in, two sets may be arranged. The distance from the shooting optical axis to the light source may be different between the two sets. Also, all light sources are arranged side by side in the scanning direction. FIG. 5 shows an image of two sets of light sources formed on the pupil of the eye to be inspected and an aperture image of the diaphragm. In this case, a light projecting region is formed on the pupil by the images of the two sets of light sources, and a light receiving region is formed by the aperture image of the diaphragm.

Which of the two sets is used for imaging may be selected according to the pupil diameter of the eye to be inspected. That is, when the pupil diameter is sufficiently large, the light source may be selected from a set arranged on the outer side. In this case, the reflected image is likely to be reduced. When the pupil diameter is small, the light source may be selected from a set arranged inside.

Further, for example, the clearance may be changed by switching the size or shape of the light receiving region. For example, when the light receiving region is formed as an aperture image of a diaphragm, the clearance may be changed by switching one arranged on the optical path between a plurality of diaphragms having different aperture sizes. .. Further, the clearance may be changed by using a variable aperture diaphragm as the diaphragm.

<Removal of artifacts by image processing>
The control unit selectively projects the illumination light from one of the two projection regions to the fundus of the eye to capture the first fundus image, and then further sets the projection area to which the illumination light is projected to the other. It may be switched to, and the illumination light may be selectively projected from the other side to take a second fundus image. By taking such two shots, it is possible to obtain two fundus images in which the appearance positions of artifacts such as the reflected image by the objective lens are different from each other depending on the light projection region used for the shooting. The imaging may be performed between the first imaging and the second imaging without changing the positional relationship between the eye to be inspected and the imaging optical system. Further, it is desirable that the acquisition of the second fundus image is continuously and automatically executed from the acquisition of the first fundus image.

In the present embodiment, when two fundus images are taken, it is not necessary to change the positional relationship between the eye to be inspected and the taking optical system, and moreover, it is relatively possible to switch the lighting of the light source or drive the shutter. The light projection area on the pupil of the eye to be inspected can be switched in a short time. Therefore, two fundus images can be taken in a short time. As a result, even if the first fundus image and the second fundus image are continuously captured, the burden on the subject is suppressed. Further, even if the illumination light is visible light, the second image is taken immediately after the first image is taken, so that the miosis caused by the first image is given in the second image. The effect can be suppressed.

Here, examples of the effect of miosis include vignetting of the illumination light and the fundus reflected light with the iris, resulting in darkening of the fundus image. The effect of vignetting (change in brightness) between the central part of the image and the peripheral part of the image is not always uniform. For example, in the peripheral portion of an image, the larger the shooting angle of view, the more likely it is to be affected by vignetting.

In the present embodiment, one fundus image (hereinafter, referred to as “composite image”) may be generated by combining these two fundus images. The compositing process is executed by the image processing unit. The image processing unit may be an image processing processor separate from the control unit, or may be partially or wholly used by the processor of the control unit.

In the present embodiment, a compositing process is performed in order to obtain an image in which the influence of the artifact is suppressed. As the synthesis method, there may be various methods as illustrated below.

For example, a composite image may be generated by replacing a region containing an artifact in one of the two fundus images with a part of the other fundus image corresponding to the region (see FIG. 6). ). At this time, the replacement may be performed in units of scanning lines. For example, when the above-mentioned reflected image is generated as an artifact, a composite image may be generated by replacing the reflected image generated at the center of the image of one fundus image with the corresponding region in the other fundus image.

Further, a composite image may be generated as an averaging image of the two fundus images. In this case, the addition averaging process may be performed by giving different addition ratios between the reflected image and the other regions.

The region where the reflected image is generated is a substantially constant range with respect to the shooting optical axis, although there is some variation depending on the diopter. Therefore, in the two fundus images, the region to be combined with the other image in the composition process may be predetermined. However, the present invention is not limited to this, and a reflection image detection process may be performed on the fundus image, and a region to be combined may be individually set based on the result of the detection process. In addition, a region to be combined may be set according to the diopter. Further, execution / non-execution of the synthesis process may be selected according to the diopter of the eye to be inspected.

The control unit captures the first fundus image based on scanning only a part of the scanning range corresponding to the composite image, switches the light projection area, and then scans the remaining part. A composite image may be generated by taking a first image of the fundus and synthesizing (collaborating) each image of the fundus. In this case, it is preferable that the scanning range is divided into two around the photographing optical axis, and the fundus image is photographed in each of the divided two scanning ranges. In this case, the compositing process is not necessarily limited to the image processing. For example, a composite image can be formed on the imaging surface by switching the projection region for projecting the illumination light at the timing when the illumination light reaches the divided position of the scanning range.

In this case, it is preferable that the relationship between the scanning range on the fundus and the projection area where the illumination light is projected intersects between the two fundus images. For example, when two projection regions are arranged side by side in the vertical direction and the illumination light is scanned in the vertical direction on the fundus, when the illumination light is passed from the upper projection area, the lower half of the fundus is used. When the first fundus image is taken based on the scan and the illumination light is passed from the lower projection area, the second fundus image is taken based on the scan of the upper half of the fundus and both are used. A composite image may be generated. In this case, the reflected image of the objective lens and the image of the portion where the artifact such as flare is hard to be included are combined with each other in relation to each light projection region. Therefore, it is possible to obtain a composite image in which artifacts are suppressed.

Instead of this compositing process, the following shooting control may be executed. That is, the projection region may be switched by the control unit at the timing when the illumination light scanning on the fundus during imaging reaches the boundary position of the two divisions. A composite image in which the reflected image is suppressed is generated without the need for a composite process.

<Composite of 3 fundus images>
As shown in FIG. 7, a first fundus image taken by selectively irradiating illumination light from one of the two projection regions and a second fundus image taken by selectively irradiating illumination light from the other. In addition to, the artifacts are suppressed by taking a picture of the third fundus image taken by simultaneously irradiating the illumination light from both of the two projection regions and synthesizing these three fundus images. You may want to generate a composite image. In this case, the central part of the image (the area of the two reflected images) in the third fundus image is a part of the corresponding area in the first fundus image and a part of the corresponding area in the second fundus image. A composite front image may be generated by replacing each of them.

Since the third fundus image was taken by simultaneously irradiating the illumination light from both of the two projection regions, the unevenness of brightness is smaller than that of the first fundus image and the second fundus image. In the composite image, only the peripheral region of the artifact is changed from the third fundus image in the third fundus image, so that the unevenness of brightness can be suppressed.

<Correction processing>
In the above compositing process, various correction processes may be involved when compositing a plurality of fundus images. For example, shading may be performed to smooth the seams. Moreover, the difference in brightness between images may be corrected. Brightness correction is useful for reducing the effect of miosis when a plurality of fundus images are taken using visible light.

<Alignment between images>
In the compositing process, the image processing unit may perform the alignment (image registration) of each fundus image. The alignment referred to here may include at least one of translation, rotation, scaling, affine transformation, non-linear deformation, and the like. For the alignment, for example, either the phase information in the fundus image, the positional information of the characteristic portion (for example, blood vessel, macula, papilla, etc.) or the like may be used.

<About shooting order>
As in the compositing process by the above replacement, one of the fundus images used in the compositing process is used as the base image, and the other fundus images are synthesized only in the vicinity of the artifact in the base image. When generating a composite image, which of the plurality of fundus images is used as the base image and which is used as the other fundus image may be selected according to the shooting order of each image.

For example, when a plurality of fundus images are continuously photographed using visible light as illumination light, miosis starts immediately after the first image is photographed, so that the fundus images captured thereafter are affected by the miosis. There is a risk of Therefore, in the above-mentioned compositing process, a composite image in which the influence of miosis is reduced can be obtained by using the first captured image as a base image.
<Application to other artifacts>
In the above description, the case where the reflected image on the lens surface of the objective lens is suppressed by the compositing process has been described, but the above compositing process can be applied to artifacts other than the reflected image. Specifically, in the first fundus image taken by selectively irradiating the illumination light from one of the two projection regions and the second fundus image taken by selectively irradiating the illumination light from the other. It is applicable to artifacts that occur at different positions. As an example, the above synthetic treatment can be applied to eyelashes, flares and the like.

<Second Embodiment>
Next, the second embodiment will be described. In the second embodiment, the fundus photography apparatus may include at least a photographing optical system (see FIG. 10), a driving unit (see FIGS. 9 and 12), and a control unit (see FIG. 12). good. In addition, the fundus camera may have at least one of an anterior eye observation optics, an input interface, and a monitor.

<Shooting optical system>
The photographing optical system in the second embodiment is used for photographing a fundus image by projecting and receiving illumination light on the fundus of the eye to be inspected. The photographing optical system according to the second embodiment includes at least a light emitting / receiving separating unit and a light receiving element. In addition, the photographing optical system may have at least one of a light source, an objective optical system (for example, an objective lens), an optical path branching portion, and the like.

In the second embodiment, at least the same optical system as in the first embodiment can be used as the photographing optical system. However, the present invention is not limited to this, and various optical systems can be used as the photographing optical system of the second embodiment. More specifically, the photographing optical system may be a scanning type optical system that scans the photographing light on the tissue of the eye to be inspected for photographing, or may be a non-scanning type optical system. As an example of the scanning type optical system, a spot scanning type optical system that two-dimensionally scans the spot-shaped photographing light on the tissue may be used, or a line that scans the line-shaped photographing light in one direction. It may be a scan type optical system. In this case, any one of a point light receiving element, a line sensor, a two-dimensional light receiving element (photographing element), and the like can be appropriately adopted as the light receiving element. The optical system of the first embodiment is an example of a line scan type optical system. Further, as an example of the non-scanning type optical system, an optical system of a general fundus camera and the like can be mentioned.

The light emitting / receiving separation unit in the second embodiment includes, at least, an area where the illumination light is projected (light projection area) and an area where the fundus reflected light due to the illumination light is extracted (light receiving area) on the pupil of the eye to be inspected. , Is separated. Then, the fundus reflected light taken out from the light receiving region is received by the light receiving element.

The light emitting / receiving separating unit may form each region on the pupil conjugate surface so that one of the light emitting region and the light receiving region sandwiches the other. As a specific example, as in the first embodiment, one region (the projection region in the first embodiment) is formed at two completely separated positions, and the other region (in the first embodiment) is formed between them. A light receiving region) may be formed. Further, as another specific example, the light emitting region and the light receiving region may be formed concentrically as in a general fundus camera or the like.

In the second embodiment, the light emitting / receiving separation unit is composed of one or more members arranged in one or both of the light emitting light path and the light receiving light path. As in the first embodiment, the light emitting / receiving separating unit may include a light emitting path of the illumination light and a plurality of members arranged in the light receiving path. For example, an optical path branching portion that combines and branches a light projecting light path and a light receiving light path may also be used as a light emitting and receiving separating unit.

<Anterior eye observation optical system>
The ophthalmologic imaging apparatus of the second embodiment may have an anterior eye observation optical system (see FIG. 10) and may be able to acquire an anterior eye observation image via the anterior eye observation optical system. The anterior eye observation optical system may have at least an image sensor. The anterior eye observation image is used to adjust the positional relationship between the eye to be inspected and the photographing optical system (that is, for alignment, tracking, etc.). The anterior segment observation image may be, for example, a frontal image of the anterior segment. At the time of alignment, the anterior ocular segment observation image may be displayed on the monitor. As a result, the examiner can grasp the real-time alignment state.

The anterior eye observation optical system may share a part of the photographing optical system and the optical system. The photographing optical system and the anterior eye observation optical system may be unitized, and the positional relationship between the two may be integrally changed with the eye to be inspected by a driving unit described later.

The anterior eye observation image may be imaged by an image pickup element separate from the image pickup element of the photographing optical system. In addition to this image pickup element, the anterior eye observation optical system may include various optical elements such as a light source.

Further, the fundus photography apparatus may have an alignment index projection optical system that projects an alignment index onto the eye to be inspected. Then, the alignment may be guided based on the alignment index formed on the observation image of the anterior segment or the fundus.

<Drive>
The drive unit is a mechanism for changing (adjusting) the positional relationship between the eye to be inspected and the photographing optical system. By changing the positional relationship, the positional relationship between the light projecting region and the light receiving region on the pupil of the eye to be inspected and the pupil region changes.

The drive unit may have an actuator that changes the positional relationship between the eye to be inspected and the photographing optical system based on a signal from the control unit, or the examiner may change the positional relationship between the eye to be inspected and the photographing optical system. It may be a mechanical mechanism that changes according to the force given by.

The drive unit may, for example, displace the imaging unit including the imaging optical system (and the anterior eye observation optical system), or the face support unit (for example, the jaw receiver) that supports the subject's face. The table) may be displaced, or both may be combined.

<Control unit>
In the second embodiment, the control unit executes the alignment reference position setting process and the alignment guidance process. In the setting process, the control unit sets the alignment reference position, which is the alignment reference (alignment deviation reference) between the eye to be inspected and the photographing optical system, in consideration of vignetting of the luminous flux passing through the light projecting region and the light receiving region. .. The positional relationship between the eye to be inspected and the imaging optical system is adjusted (that is, alignment) with the alignment reference position as the target.

The control unit may selectively be able to set at least one of a first reference position and a second reference position different from the first reference position. The first reference position referred to here is a position assuming that the entire light emitting region and the light receiving region are formed in the pupil region of the eye to be inspected. The second reference position is a position assuming that a part of either the light projecting region or the light receiving region is formed outside the pupil region of the eye to be inspected. The second reference position is a position that is assumed to be formed in the pupil region for the remaining part of the light projecting region and the light receiving region (at least a part of each of the light projecting region and the light receiving region).

For example, each of the first reference position and the second reference position may be predetermined or may be set for each eye to be inspected. For example, each of the first reference position and the second reference position may be set based on the observation image of the anterior eye portion or the fundus. The fundus observation image is a kind of fundus image acquired through a photographing optical system, and may be a moving image captured by using invisible light such as infrared light as illumination light.

The first reference position may be, for example, a position where it is assumed that the entire light projecting region and the light receiving region are formed in the pupil region in the required pupil diameter (design value). In this case, for example, the first reference position may be a position where the imaging optical axis and the center of the eye to be inspected (for example, the apex of the cornea or the center of the pupil) coincide with each other.

The second reference position may be a position where the positional relationship between the eye to be inspected and the photographing optical system is offset in the direction intersecting the photographing optical axis with respect to the first reference position. Further, the second reference position may be a position different from both the position where the photographing optical axis and the corneal apex coincide with each other and the position where the photographing optical axis and the pupil center coincide with each other. Since the positional relationship between the light projecting region and the light receiving region and the pupil region of the eye to be inspected changes depending on the offset, the influence of vignetting can be improved.

The direction and amount of the offset of the second reference position with respect to the first reference position are, for example, based on the pupil diameter and the first reference position. It may be appropriately set as long as it is formed outside the pupil region and the remaining part (at least a part of each of the light projecting region and the light receiving region) is formed inside the pupil region. At this time, the pupil diameter used for determining the offset may be, for example, a design value or an actually measured value.

Further, at least one of the direction and the amount of the offset of the second reference position with respect to the first reference position may be predetermined according to the positional relationship between the light projecting region and the light receiving region. For example, the offset direction may be set in the direction in which the ratio of the light emitting region to the light receiving region included in the pupil region changes.

Further, at least one of the offset direction and the amount may be set based on the observation image of the anterior segment of the eye or the fundus. For example, even if the area ratio of the light projecting region and the light receiving region arranged in the pupil region is calculated based on the anterior eye image, and at least one of the offset direction and the amount is set according to the area ratio. good.

Here, the alignment reference position may be set in consideration of vignetting due to the iris. Alternatively or additionally, vignetting due to the eyelids may be taken into consideration when setting the alignment reference position. The state of vignetting may be grasped from, for example, an observation image of the anterior segment of the eye or the fundus.

Here, the control unit may set the alignment reference position based on the information regarding the pupil region of the eye to be inspected. The information regarding the pupil region may be, for example, at least information indicating the size of the pupil region (specific examples, area information of the pupil region, pupil diameter information, etc.). Further, the information regarding the pupil region may be information indicating the position and shape of the pupil region. The light projecting area and the light receiving area are formed at substantially known positions and sizes on the pupil of the eye to be inspected. Therefore, it is possible to determine in which case the first reference position or the second reference position the light emitting / receiving is performed more preferably based on the information regarding the pupil region. Therefore, for example, the control unit selectively selects one of the first reference position and the second reference position in which both the light emitting region and the light receiving region can be arranged more evenly in the pupil region. It may be set.

Information about the pupillary region may be acquired from the anterior ocular segment observation image, or may be acquired as a result of measurement or imaging with another device. Various processes are known as methods for setting the pupil region from the anterior segment observation image, and these can be appropriately used. Also, when acquired on the basis of measurements or imaging with other devices, information about the pupillary region is acquired via any of the networks connected to the ophthalmologic imaging device, external storage media, input interfaces, etc. May be done.

Further, the control unit may set the alignment reference position based on the information regarding the brightness in the fundus observation image. In the present embodiment, at least the second reference position may be set based on the information regarding the brightness in the fundus observation image. The information on the brightness may be, for example, information based on various statistics obtained from the histogram of the brightness value of the fundus image. Here, the less the influence of vignetting is, the brighter the fundus observation image is, and the unevenness of brightness at each position is reduced. Therefore, for example, the control unit acquires a plurality of fundus observation images in a plurality of alignment states in which the positional relationship between the eye to be inspected and the photographing optical system is different from each other, and is based on information on the brightness of the plurality of fundus observation images. The alignment reference position may be set. For example, the position where the dispersion of the brightness in the fundus image is maximized may be predicted from a plurality of fundus observation images, and the position may be set as the alignment reference position. Further, for example, the position where the average brightness value in the fundus image is maximized may be predicted from a plurality of fundus observation images, and the position may be set as the alignment reference position. In this case, a positional relationship in which the efficiency of light reception and reception is improved can be set as the alignment reference position.

The control unit guides the alignment based on the alignment deviation from the alignment reference position. Here, the alignment guidance may be a so-called auto alignment method or a manual alignment method. In the auto-alignment method, the control unit may drive and control the drive unit based on the alignment deviation from the alignment reference position.

Further, in the manual alignment method, the control unit displays the front eye observation image on the monitor and guides the operation to the target position (for example, an electronic reticle) on the front eye observation image. It may be displayed based on the set alignment reference position. In this case, the ophthalmologic imaging apparatus may include an operation input unit that accepts the operation of the examiner and drives the drive unit according to the operation to adjust the relative position. The operation input unit may be an input interface for inputting an operation for driving the actuator of the drive unit, or may directly act on the mechanical drive unit.

As a result of the alignment guidance, the alignment may be completed when the deviation from the alignment reference position is within the allowable range. Subsequently, fine adjustment, diopter correction, etc. based on the fundus observation image may be executed. Then, after the completion of various adjustments, the control unit may automatically perform fundus photography. Further, when shooting is performed based on the release operation by the examiner, a display prompting the release operation may be displayed on the monitor.

<Alignment reference position setting according to the presentation position of the fixation target>
Further, the alignment reference position may be set in conjunction with the presentation position of the fixation target. In this case, the ophthalmologic imaging apparatus may further include an fixation optical system that presents an fixation target to the eye to be inspected. The optometry optical system may be able to change the direction of optometry by switching the position of the optometry target.

The shape of the pupil region on the pupil conjugate surface changes by switching the presentation position of the fixation target and changing the angle between the visual axis of the eye to be inspected and the optical axis of photography. Therefore, the control unit can satisfactorily capture the fundus image of the eye to be inspected at each of the fixation target presentation positions by setting the alignment reference position according to the fixation target presentation position.

<Operation in a mode in which the light emitting / receiving separation unit forms at least two light emitting regions>
Similar to the first embodiment, the light emitting / receiving separation unit may form at least two light emitting regions having different positions on the pupil of the eye to be inspected. The light receiving region is preferably formed so as to be sandwiched between the two projection regions.

In this case, in the second reference position, one of the two light projection regions together with the light receiving region may be arranged in the pupil region of the eye to be inspected with priority over the remaining one light projection region. The control unit may guide the alignment by selecting at least two of the first reference position and the second reference position. The first reference position may be a position where the center of the eye to be inspected (for example, either the apex of the cornea or the center of the pupil) coincides with the optical axis of imaging, and the first reference position is The center of the eye to be inspected and the positions of the centers of gravity of the two light emitting regions and the light receiving regions may coincide with each other.

In this way, when the alignment is performed with reference to the first reference position, the two light projection regions are evenly arranged in the pupil region of the eye to be inspected together with the light receiving region, so that the pupil region of the eye to be inspected is sufficiently large. In addition, it is easy to take a good fundus image with a sufficient amount of light. However, when the pupil diameter is small, it is difficult to arrange both of the two projection regions in the pupil at the same time, or if each of the two projection regions is arranged so as to partially overlap the iris, the fundus It is conceivable that the amount of illumination light that reaches the area is insufficient (see FIG. 8A). Therefore, in this case, it is preferable that the alignment is performed with the second reference position as a reference. At the second reference position, one of the two projection regions is arranged together with the light receiving region in the pupil of the eye to be inspected with priority over the remaining one projection region (see FIG. 8B). At this time, the remaining one projection region may be arranged outside the pupil. When the alignment to the second reference position is completed, both the one light emitting region and the light receiving region are well arranged in the pupil, so that the eye to be inspected having a smaller pupil diameter can be photographed satisfactorily.

The first reference position and the second reference position may be selected, for example, according to the size of the pupil region of the eye to be inspected. For example, if the size of the pupil region is larger than the threshold value, the first reference position may be selected, and if the pupil region is smaller than the threshold value, the second reference position may be set. .. That is, the second photographing mode is used to photograph an eye having a relatively small pupil diameter. At this time, the threshold value may be, for example, a value corresponding to the arrangement interval of the two light projection regions on the pupil of the eye to be inspected.

Further, of the two projection regions formed on the pupil conjugate surface, the regions through which the illumination light passes in the fundus photography may be different from each other between the first reference position and the second reference position. For example, when the alignment is performed at the first reference position, the fundus image may be taken by projecting the illumination light onto the fundus from both of the two projection regions formed on the pupil conjugate surface. At this time, the fundus image may be taken by passing the illumination light from both of the two projection regions at the same time. Further, as in the first embodiment, the one that allows the illumination light to pass between the two projection regions may be alternately switched, and the fundus image may be taken at each switching. Further, a composite image may be generated from at least two fundus images taken by alternately projecting light.

Further, when the alignment is performed at the second reference position, the fundus image may be taken by projecting the illumination light onto the fundus from only one of the two projection regions. At this time, it is preferable that the illumination light is projected from the two projection regions that are preferentially arranged in the pupil region.

Further, when the image is taken by aligning with the second reference position, at least one of the amount of illumination light and the gain of the image sensor is increased as compared with the case of aligning with the first reference position and taking an image of the fundus of the eye. May be photographed. The amount of light or gain may be set according to the size of the pupil area. Further, the amount of light or the gain may be set according to the ratio of the light projecting region and a part of the light receiving region arranged in the pupil region to the total area of the light projecting region and the light receiving region.

<How to arrange the two light emitting areas and the light receiving areas>
The light emitting / receiving separating unit may form the two light emitting regions and the light receiving region at positions separated in the left-right direction on the pupil conjugate surface. In this case, the width in the vertical direction tends to be narrower than the total length in the horizontal direction in these three regions. As a result, the eyelids are less likely to overlap the light emitting area and the light receiving area, and vignetting due to blinking is easily suppressed.

Further, the light emitting / receiving separating unit may be formed at positions where the two light emitting regions are separated in the vertical direction on the pupil conjugate surface of the eye to be inspected. In this case, the second reference position may be set so that one of the two light projection regions formed on the lower side is preferentially arranged in the pupil. Then, the control unit may align with the second reference position, and when taking the fundus image, may shoot the fundus image by projecting the illumination light from one of the preferentially arranged light projection regions. In this case, since the projected light region is less likely to overlap with the eyelids during blinking, vignetting due to blinking is likely to be suppressed.

<Artifact correction of fundus image taken at the second reference position>
When the light emitting / receiving separation unit forms at least two light emitting regions, the control unit may further select a third reference position as the alignment reference position and take a fundus image.

Here, the third reference position is a position in which the other light projection region is preferentially arranged together with the light receiving region as compared with one which is preferentially arranged in the pupil region in the second reference position of the two light projection regions.

The control unit first guides the alignment to the second reference position, and the first fundus image is based on at least the illumination light from the two light projecting regions that are preferentially arranged in the pupil region in the second reference position. After taking a picture of the image, the alignment is further guided to the third reference position, and the second image is based on at least the illumination light from the one that is preferentially arranged in the pupil region in the third reference position among the two projection regions. An image of the fundus of the eye may be taken. Here, it is considered that the first fundus image and the second fundus image have different positions of occurrence of artifacts such as the reflected image of the objective lens and flare. Therefore, as in the first embodiment, a composite image of two fundus images may be generated.

<Example>
Next, with reference to FIGS. 9 to 15, examples of the fundus photography apparatus according to the first embodiment and the second embodiment will be shown.

The fundus photography device 1 (hereinafter, simply abbreviated as “photographing device 1”) forms illumination light in a slit shape on the fundus of the eye to be inspected, scans a region formed in the slit shape on the fundus, and illuminates the fundus. By receiving the reflected light from the fundus, a frontal image of the fundus is taken.

<Appearance of the device>
The appearance configuration of the photographing apparatus 1 will be described with reference to FIG. The photographing device 1 has a photographing unit 3. The photographing unit 3 mainly includes the optical system shown in FIG. The photographing device 1 has a base 7, a driving unit 8, a face support unit 9, and a face photographing camera 110, and uses these to adjust the positional relationship between the eye to be inspected E and the photographing unit 3.

The drive unit 8 can move in the left-right direction (X direction) and the front-rear direction (Z direction, in other words, the working distance direction) with respect to the base 7. Further, the drive unit 8 further moves the photographing unit 3 on the drive unit 8 in the three-dimensional direction with respect to the eye E to be inspected. The drive unit 8 has an actuator for moving the drive unit 8 or the photographing unit 3 in each predetermined movable direction, and is driven based on a control signal from the control unit 80. The face support unit 9 supports the face of the subject. The face support unit 9 is fixed to the base 7.

The face photographing camera 110 is fixed to the housing 6 so that the positional relationship with respect to the photographing unit 3 is constant. The face photographing camera 110 photographs the face of the subject. The control unit 100 identifies the position of the eye E to be inspected from the captured face image, and drives and controls the drive unit 8 to align the photographing unit 3 with respect to the specified position of the eye E to be inspected.

Further, the photographing device 1 further has a monitor 120. The monitor 120 displays a fundus observation image, a fundus photography image, an anterior eye portion observation image, and the like.

<Optical system of the example>
Next, the optical system of the photographing apparatus 1 will be described with reference to FIG. The photographing apparatus 1 includes a photographing optical system (fundus photography optical system) 10 and an anterior eye portion observation optical system 40. These optical systems are provided in the photographing unit 3.

In FIG. 10, a position conjugate with the pupil of the eye to be inspected is indicated by an “Δ” on the imaging optical axis, and a fundus conjugate position is indicated by an “x” on the imaging optical axis.

The photographing optical system 10 includes an irradiation optical system 10a and a light receiving optical system 10b. In the embodiment, the irradiation optical system 10a includes a light source unit 11, a lens 13, a slit-shaped member 15a, lenses 16, 17, 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 24 and 26, a slit-shaped member 15b, and an image pickup element 28. The perforated mirror 20 is an optical path coupling portion 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 toward the eye E to be inspected, and passes a part of the light reflected from the fundus of the eye from the eye E to be inspected to the image pickup element side. Various beam splitters other than the perforated mirror 20 can be used. For example, instead of the perforated mirror 20, a mirror in which the perforated mirror 20, the translucent portion, and the reflecting portion are reversed may be used as the optical path coupling portion. However, in this case, the independent optical path of the light receiving optical system 10b is placed on the reflection side of the mirror, and the independent optical path of the light projecting optical system 10a is placed on the transmission side of the mirror. Further, the perforated mirror and the mirror as an alternative means thereof can be further replaced with a combination of a half mirror and a light-shielding portion, respectively.

In this embodiment, the light source unit 11 has a plurality of types of light sources having 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 described above, the light source unit 11 of this embodiment is provided with two light sources for each wavelength. Two light sources having the same wavelength are arranged on the pupil conjugate plane away from the photographing optical axis L. The two light sources are arranged along the X direction, which is the scanning direction in FIG. 10, and are arranged axisymmetrically with respect to the photographing optical axis L. As shown in FIG. 10, the outer peripheral shape of the two light sources may be a rectangular shape in which the direction intersecting the scanning direction is longer than the scanning direction.

Light from the two light sources passes through the lens 13 and is applied to the slit-shaped member 15. In this embodiment, the slit-shaped member 15a has a light-transmitting portion (opening) formed elongated along the Y direction. As a result, the illumination light is formed in a slit shape on the fundus conjugate surface (the region illuminated in the slit shape on the fundus is shown as reference numeral B).

In FIG. 10, the slit-shaped member 15a is displaced by the driving unit 15c so that the translucent portion crosses the photographing optical axis L in the X direction. As a result, scanning of the illumination light in this embodiment is realized. In this embodiment, scanning is also performed by the slit-shaped member 15b on the light receiving system side as well. 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 one driving unit (actuator).

In the irradiation optical system 10a, the image of each light source is relayed by the optical system from the lens 13 to the objective lens 22 and imaged on the pupil conjugate surface. That is, images of the two light sources are formed at positions separated from each other with respect to the scanning direction on the pupil conjugate surface. In this way, in this embodiment, the two projection regions P1 and P2 on the pupil conjugate surface are formed as images of the two light sources.

Further, the slit-shaped light that has passed through the slit-shaped member 15a is relayed by the optical system from the lens 16 to the objective lens 22 to form an image on the fundus Er. As a result, the illumination light is formed in a slit shape on the fundus Er. The illumination light is reflected on the fundus Er and is extracted from the pupil Ep.

Here, since the opening of the perforated mirror 20 is conjugate with the pupil of the eye to be inspected, the fundus reflected light used for capturing the fundus image passes through the image (pupil image) of the perforated mirror opening on the pupil of the eye to be inspected. Limited to some. As described above, the image of the opening on the pupil of the eye to be inspected becomes the light receiving region R in this embodiment. The light receiving region R is formed by being sandwiched between two light projecting regions P1 and P2 (images of two light sources). Further, as a result of appropriately setting the imaging magnification of each image, the diameter of the aperture, and the arrangement interval of the two light sources, the light receiving region R and the two light projecting regions P1 and P2 do not overlap each other on the pupil. Is formed in. As a result, the occurrence of flare is satisfactorily reduced.

The fundus reflected light that has passed through the openings of the objective lens 22 and the perforated mirror 20 forms a slit-shaped region of the fundus Er at the fundus conjugate position via the lenses 24 and 26. At this time, harmful light is removed by arranging the translucent portion of the slit-shaped member 15b at the position of the image formation.

The image sensor 28 is arranged at the fundus conjugate position. In this embodiment, a relay system 27 is provided between the slit-shaped member 15b and the image pickup element 28, whereby both the slit-shaped member 15b and the image pickup element 28 are arranged at the fundus conjugate position. As a result, both the removal of harmful light and the imaging are performed well. Instead of this, the relay system 27 between the image pickup device 28 and the slit-shaped member 15b may be omitted, and both may be arranged close to each other. In this embodiment, a device having a two-dimensional light receiving surface is used as the image sensor 28. For example, it may be CMOS, two-dimensional CCD or the like. An image of the slit-shaped region of the fundus Er, which is imaged by the translucent portion of the slit-shaped member 15b, is projected on the image sensor 28. The image sensor 28 is sensitive to both infrared light and visible light.

In this embodiment, as the slit-shaped illumination light is scanned on the fundus Er, an image (slit-shaped image) of the scanning position on the fundus Er is sequentially projected for each scanning line of the image sensor 28. In this way, the entire image of the scanning range is projected onto the image sensor in a time-division manner. As a result, a frontal image of the fundus Er is captured as the overall image of the scanning range.

In the embodiment, the scanning unit in the light receiving system is a device that mechanically scans the slit, but the scanning unit is not necessarily limited to this. For example, the scanning unit on the light receiving optical system side may be a device that electronically scans the slit. As an example, when the image sensor 28 is CMOS, scanning of the slit may be realized by the rolling shutter function of CMOS. In this case, by displacing the area exposed on the imaging surface in synchronization with the scanning portion in the light projection system, it is possible to efficiently take a picture while removing harmful light. Further, a liquid crystal shutter or the like can also be used as a scanning unit that electronically scans the slit.

The photographing optical system 10 has a diopter correction unit. In this embodiment, diopter correction units are provided in each of the independent optical path of the irradiation optical system 10a and the independent optical path of the light receiving optical system 10b. The projection optical system 10a can change the distance between the lenses 16 and 17, and the light receiving optical system 10b can change the distance between the lenses 24 and 26, whereby diopter correction is performed. The photographing apparatus 1 has drive units 16a and 26a (see FIG. 12) for changing the distance between the lenses, and the drive units 16a and 26a of the irradiation optical system 10a and the light receiving optical system 10b are mutually driven. It is driven in conjunction.

The diopter correction unit is not limited to this. For example, even if the diopter correction is performed by moving the light sources 11a to 11d in the optical axis direction while maintaining the positional relationship of at least three of the light sources 11a to 11d, the slit-shaped members 15a and 15b, and the image sensor 28. good.

The scanning unit of the ophthalmic apparatus may be, for example, an optical chopper as shown in FIG. The optical chopper has a wheel with a plurality of slits formed on the outer circumference, and by rotating the wheel, the slits can be scanned at high speed.

Here, in FIG. 10, the light source unit 11 to the mirror 18 of the irradiation optical system 10a and the perforated mirror 20 to the image pickup element 28 of the light receiving optical system 10b are arranged in parallel in the X direction. The optical chopper can be applied as a scanning unit by rotating the directions of the opening mirror 20 and the mirror 18 by 90 ° from the illustrated state and arranging them in parallel in the Y direction. In this case, by crossing the optical axis of the irradiation optical system 10a and the optical axis of the light receiving optical system 10b at two points, the upper end and the lower end of the wheel, one optical chopper can be used for the light emitting system and the light receiving system. Scanning can be easily synchronized.

<Anterior eye observation optical system>
Next, the anterior segment observation optical system 40 will be described. The anterior eye observation optical system 40 shares the objective lens 22 and the dichroic mirror 43 with the photographing optical system 10. The anterior eye observation optical system 40 further includes a light source 41, a half mirror 45, an image pickup device 47, and the like. The image pickup device 47 is a two-dimensional image pickup device, and is arranged at a position optically conjugate with, for example, the pupil Ep. 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 40 shown in FIG. 10 is only an example, and the anterior segment may be imaged in an optical path independent of other optical paths.

<Control system of the embodiment>
Next, the control system of the photographing apparatus 1 will be described with reference to FIG. In this embodiment, the control unit 100 controls each unit of the photographing device 1. Further, for convenience, the image processing of various images obtained by the photographing device 1 is also performed by the control unit 100. In other words, in this embodiment, the control unit 100 also serves as an image processing unit.

The control unit 100 is a processing device (processor) having an electronic circuit that performs control processing of each unit and arithmetic processing. The control unit 100 is realized by a CPU (Central Processing Unit), a memory, or the like. The control unit 100 is electrically connected to the storage unit 101 via a bus or the like.

Various control programs, fixed data, and the like are stored in the storage unit 101. Further, temporary data or the like may be stored in the storage unit 101.

The image captured by the photographing device 1 may be stored in the storage unit 101. However, the present invention is not necessarily limited to this, and the captured image may be stored in an external storage device (for example, a storage device connected to the control unit 100 via LAN and WAN).

Further, the control unit 100 includes the drive unit 8, the light sources 11a to 11d, the drive unit 15c, the drive unit 16a, the drive unit 26a, the image sensor 28, the light source 41, the image sensor 47, the input interface 110, the monitor 120, and the like. It is electrically connected.

Further, the control unit 100 controls each of the above members based on the operation signal output from the input interface 110 (operation input unit). The input interface 110 is an operation input unit that accepts the operation of the examiner. For example, it may be a mouse, a keyboard, or the like.

<Explanation of operation of the example>
Next, the shooting operation will be described based on the flowcharts of FIGS. 13 and 14.

The photographing device 1 may automatically start the photographing operation when the face of the subject is arranged with respect to the face support portion 9 and is included in the photographing range of the face detection camera 110.

First, imaging by the face detection camera 110 and the anterior eye observation optical system 40 comes to be performed in parallel (S1), and alignment adjustment using the imaging results of both is executed (S2).

Specifically, the control unit 100 detects the position of one of the left and right eyes included in the face image, and drives the drive unit 8 based on the position information. As a result, the position of the photographing unit 4 is adjusted to a position where the front eye can be observed.

Next, the alignment reference position is set based on the front image of the anterior segment of the eye, and the alignment is guided to the set alignment reference position. In this embodiment, the positional relationship between the eye to be inspected E and the photographing unit 3 is adjusted by the control unit 100 based on the front image of the anterior eye portion. In this embodiment, the control unit 100 is a position where the center of the pupil in the observation image of the anterior segment of the eye and the center of the image (the position of the imaging optical axis L in this embodiment) substantially coincide with each other based on the signal from the image sensor 47. A first reference position that targets the relationship is set. Then, the alignment deviation from the first reference position is detected, and the photographing unit 4 is moved in the vertical and horizontal directions in the direction in which the alignment deviation is eliminated. At this time, for example, an alignment deviation from the first reference position may be detected based on the amount of deviation between the center of the pupil and the imaging optical axis on the observation image of the anterior segment of the eye. Further, when the fundus imaging device 1 has, for example, an alignment projection optical system that projects an alignment index on the apex of the corneum, the alignment deviation may be detected based on the amount of deviation between the alignment index and the imaging optical axis. ..

Further, the control unit 100 moves the photographing unit 4 in the front-rear direction so that the anterior segment observation image is in focus on the pupil Ep.

As described above, in this embodiment, as a result of the alignment adjustment of S2, the positional relationship between the eye to be inspected and the imaging unit 4 is such that the center of the light receiving region R (that is, the optical axis of imaging) on the pupil of the eye to be inspected is the center of the pupil. It is adjusted to a position that matches (the first reference position in this embodiment).

In this embodiment, after the alignment to the first reference position is completed, the pupil diameter detection process (pupil information acquisition process) is executed (S3). In this embodiment, the pupil region Ep is detected from the observation image of the anterior segment of the eye, and the diameter of the detected pupil region Ep is determined. In this embodiment, it is preferable to obtain the diameter in the scanning direction. In this embodiment, the value of the diameter of the pupil region Ep acquired in the process of S3 is acquired as the pupil diameter information and stored in the memory.

Next, the control unit 100 sets the photographing mode according to the acquired pupil diameter (S4, S5, S11). In this embodiment, the pupil diameter is first compared to the threshold (S4). The threshold value is a value corresponding to the arrangement interval of the two light projection regions P1 and P2 on the pupil of the eye to be inspected, and in this embodiment, the total length W (see FIG. 10) is used as an example of the threshold value. Instead of the total length W, for example, the distance between the centers of the projection regions P1 and P2 may be used as a threshold value. Here, in this embodiment, the threshold value is assumed to be a fixed value regardless of the diopter correction amount. For example, a fixed value assuming a 0D eye is used as the threshold value.

However, since the arrangement interval between the two projection regions P1 and P2 varies depending on the diopter correction state, it depends on the diopter error of the eye to be inspected (or when the slit image is formed on the fundus Er). A threshold value may be obtained each time (according to the amount of diopter correction), and the obtained threshold value may be compared with the pupil diameter.

As a result of comparison between the pupil diameter and the threshold value, when the pupil diameter is larger than the threshold value (S4; Yes), the first imaging mode is set (S5). On the other hand, when the pupil diameter is equal to or less than the threshold value (S4; No), the second imaging mode is set (S11).

<First shooting mode>
If the pupil diameter is larger than the above threshold value, the two projection regions P1 and P2 and the light receiving region R can be arranged in the pupil Ep. Therefore, in the control unit 100, the center of the light receiving region R (in this embodiment, the position of the photographing optical axis L and also the center of gravity of the two light projecting regions P1 and P2 and the light receiving region R) is abbreviated as the pupil center. The drive unit 8 is driven to adjust the positional relationship between the eye E to be inspected and the imaging unit 4 with the matching alignment state as the target (that is, with the first reference position as the target).

After the first photographing mode is set, the control unit 100 starts photographing and displaying the fundus observation image (S6). Specifically, the control unit 100 turns on the light sources 11c and 11d at the same time and starts driving the drive unit 15c, and the slit-shaped illumination light is repeatedly scanned in a predetermined range on the fundus Er. A fundus image taken in substantially real time is generated as a fundus observation image at any time based on the signal output from the image sensor 28 every predetermined number of scans (at least once). The control unit 100 may display the fundus observation image as a substantially real-time moving image on the monitor 120.

Next, various adjustment processes are executed based on the fundus observation image (S7). For example, diopter correction, fine adjustment of the alignment target position, and the like may be executed.

After that, the acquisition control of the fundus photographed image is executed automatically or based on the release operation.

In this embodiment, the control unit 100 alternately lights the light sources 11a and 11b that emit visible light, and scans the illumination light on the fundus Er each time the light sources 11a and 11b are turned on, so that the first fundus An image and a second fundus image are taken (S8, S9).

Then, the control unit 100 synthesizes the first fundus image and the second fundus image to generate a composite image. Since miosis starts immediately after the first fundus image is taken, the second fundus image taken later out of the two fundus images becomes the first fundus image due to the influence of keratinization due to the miosis. The image may be darker than the image.

Therefore, in this embodiment, an image in which the region where the reflection image of the central portion is generated in the first fundus image is replaced by the corresponding region in the second fundus image is generated as a composite image. As a result, it is possible to obtain a fundus image in which the influence of the reflected image is suppressed on the first fundus image and the second fundus image as a composite image, and it is possible to suppress the influence of vignetting due to miosis.

<Second shooting mode>
Next, the operation when the second shooting mode is set will be described. As determined in the process of S4, when the pupil diameter is equal to or less than the threshold value, the two light emitting regions P1 and P2 and the light receiving region R cannot be satisfactorily arranged in the pupil Ep. Therefore, the control unit 100 readjusts the alignment state. At that time, the control unit 100 sets the second reference position based on the front eye portion observation image. The second reference position is an alignment reference position such that one of the two light projecting regions P1 and P2 (here, the region P1) is placed in the pupil Ep together with the light receiving region R in preference to the other. (S12). As an example, a second reference position is set in which an alignment state in which the midpoint between the light projecting region P1 and the light receiving region R coincides with the center of the pupil is targeted. Here, for example, the positional relationship between the eye to be inspected and the photographing optical system may be offset in the X direction with respect to the alignment reference position (that is, the first reference position) in the alignment process of S2. Here, only W / 4 (for W, see FIG. 10) is offset. However, the offset amount is not necessarily limited to this.

Then, the control unit 100 detects the alignment deviation from the second reference position and moves the photographing unit 4 in the vertical and horizontal directions in the direction in which the alignment deviation is eliminated. At this time, for example, even if an alignment deviation from the second reference position is detected based on the amount of deviation between the center of the pupil (or the apex of the cornea) and the imaging optical axis on the observation image of the anterior segment of the eye and the above offset. good. As a result of the alignment with respect to the second reference position, the light projecting region P1 and the light receiving region R are well arranged in the pupil Ep. Which of the two light projection regions P1 and P2 is preferentially arranged in the pupil Ep may be predetermined or may be selectable.

After the alignment state is readjusted, the acquisition of the fundus observation image is started. Here, when the fundus observation image is obtained in the first shooting mode, the two light sources 11c and 11d are turned on at the same time, but in the second shooting mode, the light projection region P1 preferentially arranged in the pupil Ep. Only the light source corresponding to (in this embodiment, the light source 11c) may be turned on. As a result, the observation image of the fundus Er may be acquired by irradiating the fundus with illumination light for observation only from the light projection region P1. However, the present invention is not necessarily limited to this, and the observation image of the fundus Er may be acquired by turning on the light source corresponding to both the projection regions P1 and P2.

Then, various adjustment processes are executed based on the fundus observation image (S14), and after the adjustment is completed, the operation of photographing the fundus photographed image in the second photographing mode is executed automatically or based on the release operation. (S15).

In the second shooting mode of this embodiment, the control unit 100 lights only the light source 11a corresponding to the light projecting region P1 preferentially arranged in the pupil Ep among the two light sources 11a and 11b that emit visible light. Take a fundus image. This fundus image is stored in the memory as a captured image. Compared with the case where the two light sources 11a and 11b are turned on at the same time, the captured image has fewer places where strong reflection occurs on the objective lens 22, so that the influence of the reflected image is reduced. Further, the illumination light is irradiated to the outside of the pupil Ep such as the iris and the sclera, and the reflected light becomes harmful light and is suppressed from affecting the fundus image. Therefore, even when the pupil diameter of the eye to be inspected is small, a good fundus image can be taken.

Here, in the present embodiment, the control unit 100 includes the amount of light emitted from the light sources 11a and 11b during shooting in the second shooting mode and the gain in the image sensor 28 that receives the fundus reflected light. At least one of them is increased with respect to the time of shooting in the first shooting mode. Thereby, the brightness and contrast of the fundus image captured in the second imaging mode can be improved. The amount of light and the gain may be set according to the size of the pupil region of the subject (for example, the pupil diameter).

Although the above description has been given based on the embodiments, the contents of the embodiments can be changed as appropriate in carrying out the present disclosure.

For example, in the above embodiment, the positional relationship between the eye to be inspected and the imaging unit is automatically adjusted by the control unit. However, the present invention is not necessarily limited to this, and the positional relationship between the eye to be inspected and the imaging unit may be manually adjusted by the examiner.

In this case, as shown in FIG. 15, the control unit may display at least the anterior eye portion observation image on the monitor. As a result, the examiner can adjust the positional relationship between the eye to be inspected and the photographing unit while looking at the anterior eye observation image. Further, it is preferable that an electronic index Ip corresponding to at least two projection regions is displayed on the anterior segment observation image. Further, the index Ip corresponding to the light receiving region may be displayed. The positions and sizes of the indexes Ip and Ir may be constant on the front eye observation image, or may be changed according to the diopter correction amount in the photographing optical system.

By displaying the indexes Ip and Ir, the positional relationship between the eye to be inspected and the imaging unit can be adjusted while confirming the positional relationship between the light projecting region and the light receiving region and the pupil in real time.

Further, at this time, the fundus observation image may be displayed on the monitor at the same time. Since the positional relationship between the eye to be inspected and the imaging unit can be adjusted while checking the state of uneven brightness in the fundus image, it is easy to adjust the positional relationship so that a better fundus image can be obtained.

Further, the control unit displays the anterior eye portion observation image and the fundus observation image, and individually irradiates the illumination light from each projection area (ON / OFF of the illumination light) based on the operation on the input interface. May be set to. Then, the set irradiation state may be reflected in the acquisition of the fundus observation image. As a result, the examiner can search for the imaging conditions that can obtain a good fundus image while manually changing the positional relationship between the eye to be inspected and the imaging unit and the irradiation state of the illumination light from each projection area. .. In the example of FIG. 15, by selecting the index Ip on the anterior eye portion image in combination with the cursor C, it is possible to switch ON / OFF of the illumination light from the projection region corresponding to the index Ip.

1 Fundus photography device 10 Imaging optical system 15a, 15b Slit-shaped member 15c Drive unit 100 Control unit P1, P2 Light projection area R Light reception area

Claims (5)

A light projecting separation means and a light receiving / receiving separating means for forming a light projecting region through which the illumination light passes on the pupil of the eye to be inspected and a light receiving region on the pupil of the eye to be examined from which the fundus reflected light of the illumination light is taken out at different positions. An imaging optical system including a light receiving element that receives the reflected light from the fundus of the eye taken out from the light receiving region.
A fundus photography device that includes a drive unit that adjusts the positional relationship between the eye to be inspected and the photographing optical system, and acquires a fundus image based on a signal from the light receiving element.
In addition
The light emitting / receiving separating means forms two light emitting regions having different positions on the pupil of the eye to be inspected.
As an alignment reference position that serves as a reference for alignment between the eye to be inspected and the photographing optical system, a first reference position assuming that the entire two light projection regions and the light receiving region are formed in the pupil region of the eye to be inspected. In the second reference position different from the first reference position, one of the two light projection regions together with the light receiving region is preferentially placed in the pupil of the eye to be inspected over the remaining one light projection region. It is possible to selectively set either the second reference position that is supposed to be arranged, and the alignment is guided based on the alignment deviation from the set alignment reference position, and the alignment is moved to the first reference position. When guiding the alignment, when the fundus image is taken, the illumination light is projected onto the fundus from both of the two projection regions, and when the alignment is guided to the second reference position, the fundus image is used. An optometry imaging device comprising a imaging control means for projecting the illumination light onto the fundus of the eye from only one of the two projection regions preferentially arranged in the pupil. A light projecting separation means and a light receiving / receiving separating means for forming a light projecting region through which the illumination light passes on the pupil of the eye to be inspected and a light receiving region on the pupil of the eye to be examined from which the fundus reflected light of the illumination light is taken out at different positions. An imaging optical system including a light receiving element that receives the reflected light from the fundus of the eye taken out from the light receiving region.
A fundus photography device that includes a drive unit that adjusts the positional relationship between the eye to be inspected and the photographing optical system, and acquires a fundus image based on a signal from the light receiving element.
In addition
The photographing optical system is
A slit-forming portion that forms illumination light in a slit shape on the fundus of the eye to be inspected.
It also has a scanning unit that scans the illumination light formed in the shape of a slit on the fundus in a direction orthogonal to the slit.
The light emitting / receiving separating means forms the light emitting region on the pupil of the eye to be inspected at two positions separated from each other with respect to the scanning direction of the scanning portion, and has two light receiving regions on the pupil of the eye to be inspected. It is formed so as to be sandwiched between the light projection regions.
As an alignment reference position that serves as a reference for alignment between the eye to be inspected and the photographing optical system, a first reference position assuming that the entire two light projection regions and the light receiving region are formed in the pupil region of the eye to be inspected. And, in the second reference position different from the first reference position, one of the two projection regions together with the light receiving region is preferentially placed in the pupil of the eye to be inspected over the remaining one projection region. Fundus photography including a second reference position that is supposed to be arranged and an imaging control means that can selectively set any of them and guides alignment based on the alignment deviation from the set alignment reference position. Device. The fundus photography apparatus according to claim 1 or 2, wherein at the second reference position, the remaining one of the two light projection regions is arranged outside the pupil. Equipped with an anterior segment observation optical system for acquiring anterior segment observation images
The fundus photography device according to any one of claims 1 to 3, wherein the imaging control means sets the alignment reference position based on the information about the pupil region of the eye to be inspected acquired from the anterior segment observation image. An observation image acquisition means for acquiring a fundus observation image based on the fundus image is provided.
The fundus imaging device according to any one of claims 1 to 4, wherein the imaging control means sets the alignment reference position based on information on the brightness of the fundus observation image.

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