JP7086688B2 - Imaging equipment and its control method - Google Patents

Description

The present invention relates to an image photographing apparatus and a control method thereof, and more particularly to an image photographing apparatus used for acquiring an image of a fundus of an eye to be inspected and a control method thereof.

Optical coherence tomography (OCT) utilizing multi-wavelength optical wave interference can obtain a tomographic image of a sample (particularly the fundus) with high resolution. Hereinafter, a device that captures a tomographic image by such OCT will be referred to as an OCT device.

Further, a scanning laser ophthalmoscope (SLO), which is an ophthalmologic apparatus utilizing the principle of a confocal laser scanning microscope, is also known. The SLO is a device that uses a laser as measurement light to perform a raster scan on the fundus and obtains a planar image of the fundus at high resolution and high speed from the intensity of the return light. Hereinafter, a device that captures such a flat image will be referred to as an SLO device.

In recent years, as a device for photographing the fundus, an OCT device, an SLO device, and other devices for scanning the measurement light to photograph the fundus have been widely used. Further, by increasing the beam diameter of the measured light in these fundus photography devices, it has become possible to acquire an image of the retina with improved lateral resolution.

However, with the increase in the beam diameter of the measured light, in the acquisition of the fundus image, the decrease in the SN ratio and the resolution of the image due to the aberration of the eye to be inspected becomes a problem. To solve this, adaptive optics has an adaptive optics system that measures the aberration of the eye to be inspected in real time using a wavefront sensor and corrects the aberration of the measured light generated in the eye to be inspected and its return light with a wavefront correction device. OCT devices and adaptive optics SLO devices have been developed. By using these devices, it is possible to compensate for the aberration of the eye to be inspected due to the increase in the beam diameter of the measurement light, and it is possible to acquire an image with high lateral resolution.

Here, in the adaptive optics OCT apparatus, if the beam diameter of the measurement light is increased in order to improve the lateral resolution, the depth of focus becomes shallow. When the depth of focus becomes shallow, the range in the depth direction in which an image having a high signal-to-noise ratio can be obtained is limited. Therefore, it becomes difficult to photograph the entire depth direction of the retinal layer at one time. Therefore, in order to acquire an image with a high SN ratio in a wide range in the depth direction with the adaptive optics OCT device, the focus position of the measurement light is adjusted to the layer to be imaged of the fundus retina, and a plurality of images having different focus positions are acquired. There is a need to.

When repeatedly shooting at multiple different focus positions and acquiring multiple images, it takes time from the start to the end of shooting. For this reason, it is easily affected by involuntary eye movements called fixation tremors, eye movements due to poor fixation, or facial movements. Eye movement tracking is becoming more important. In particular, in devices such as adaptive optics OCT devices and adaptive optics SLO devices that acquire images with high lateral resolution, higher accuracy of fundus tracking is important.

Patent Document 1 proposes an adaptive optics OCT device, which is an ophthalmic device that synthesizes a plurality of images having different focus positions and acquires a wide range of images in the depth direction.

In Patent Document 1, a part of the optical system of the adaptive optics OCT device and the optical system of the adaptive optics SLO device is used as a common optical path, and a focus lens is arranged in the common optical path as a diopter correction optical system. As a result, the focus positions of the adaptive optics OCT device and the adaptive optics SLO device are aligned with the position of the fundus, and the fundus tomographic image by the adaptive optics OCT device and the fundus plane image by the adaptive optics SLO device are simultaneously acquired.

In addition, a plurality of tomographic images are repeatedly acquired at a plurality of different focus positions, and a wide range of fundus tomographic images are acquired in the depth direction by synthesizing them.

Japanese Patent No. 5734411

However, in Patent Document 1, since the focus lens is arranged in the common optical path of the OCT optical system and the SLO optical system, when the focus position is adjusted by using this focus lens, the adaptive optics OCT device and the adaptive optics SLO device The focus position is adjusted by the same amount. Therefore, when the adaptive optics OCT device captures a layer having few feature points such as photoreceptor cells (for example, the inner layer of the retina), if the focus position of the adaptive optics OCT device is aligned with the layer having few feature points, the adaptive optics SLO device is simultaneously used. However, the focus position will be aligned with the layer with few feature points.

In order to perform fundus tracking based on the fundus plane image acquired by the adaptive optics SLO device while acquiring a plurality of images at different focus positions, the amount of misalignment from the feature points such as photoreceptor cells of the captured fundus plane image Is detected. Therefore, when the focus position is aligned with the layer having few feature points and the image is taken, the detection accuracy of the amount of misalignment is lowered, and highly accurate fundus tracking becomes difficult. When highly accurate fundus tracking becomes difficult, the positional deviation between each tomographic image when repeatedly taken at multiple different focus positions becomes large, and distortion occurs in the composite image obtained by synthesizing multiple tomographic images with different focus positions. It ends up.

On the other hand, a device configuration is also conceivable in which the adaptive optics OCT device and the adaptive optics SLO device are arranged in their respective dedicated optical paths instead of the common optical path of the OCT optical system and the SLO optical system. However, in this case, since each diopter correction optical system needs to correspond to the diopter range of the eye to be imaged, the movement range of the diopter correction optical system becomes wide, and the device tends to be large.

Further, in a wavefront compensator using a wavefront sensor, it is general that the optical system is mainly composed of a reflected optical system in order to reduce unnecessary stray light to the wavefront sensor. However, if each of the diopter correction optical systems is composed of a reflection optical system, the moving range of the diopter correction optical system at the time of diopter correction becomes wider, and more space is required for the arrangement, so that the device is required. Further increase in size.

Therefore, it is not sufficient to acquire a wide range of fundus tomographic images in the depth direction with high image quality and with suppressed distortion, even though the device configuration is more compact.

Although the present invention has a compact device configuration, it is possible to acquire a plurality of tomographic images by adjusting the focus position of the OCT measurement light to a predetermined position, for example, the layer to be imaged, or by changing the focus position, and SLO. To provide a device capable of maintaining the focus position of the measurement light at a predetermined position, for example, a layer to be observed, or a layer having many feature points advantageous for position detection for fundus tracking. The purpose.

In order to solve the above problems, the imaging apparatus of the present invention irradiates the test eye with OCT measurement light, receives the interference light between the OCT return light and the reference light from the test eye, and acquires a tomographic image. An optical system, an SLO optical system that irradiates the eye to be inspected with SLO measurement light and receives SLO return light from the eye to be inspected to acquire a planar image, an optical path of the OCT optical system, and an optical path of the SLO optical system. A common optical path that shares at least a part of the common optical path, a first focusing means provided in the common optical path, and at least one of the optical path of the SLO optical system or the optical path of the OCT optical system branched from the common optical path. It also has a second focus means, a control means for controlling the first focus means and the second focus means, and the control means has a plurality of tomographic images having different focus positions of the OCT measurement light. The focus position of the OCT measurement light is aligned with the focus position of each of the plurality of tomographic images, and the focus position of the SLO measurement light is maintained at a predetermined focus position. It controls the first focusing means and the second focusing means.

According to the present invention, even if the focus position of the OCT measurement light is changed to the position to be photographed, the focus position of the SLO measurement light can maintain a predetermined position.

It is a schematic diagram for demonstrating the structure of the fundus imaging apparatus which concerns on 1st Embodiment of this invention. It is a schematic diagram which shows the imaging range of the OCT apparatus and the SLO apparatus in the fundus imaging apparatus which concerns on 1st Embodiment of this invention. It is a flowchart which showed the imaging procedure of the fundus imaging apparatus which concerns on 1st Embodiment of this invention. It is a schematic diagram for demonstrating the imaging procedure of the fundus imaging apparatus which concerns on 1st Embodiment of this invention. It is a schematic diagram for demonstrating the structure of the fundus imaging apparatus which concerns on 2nd Embodiment of this invention.

Hereinafter, exemplary embodiments for carrying out the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative positions of the components, etc. described in the following embodiments are arbitrary and can be changed according to the configuration of the apparatus to which the present invention is applied or various conditions. Also, in the drawings, the same reference numerals are used between the drawings to indicate elements that are the same or functionally similar.

In the following, the retina of the human eye will be described as an inspected object, but the inspected object is not limited to this, and for example, the anterior segment of the human eye may be inspected.

[First Embodiment]
The first embodiment of the present invention will be described in detail below with reference to the drawings.

(Device configuration)
The fundus imaging system 500 as one aspect of the imaging apparatus according to the present embodiment will be described with reference to FIG. The fundus imaging system of the present embodiment includes an OCT optical system, an SLO optical system, an anterior eye observation optical system, a fixative lamp optical system, and a control unit. In this embodiment, the entire optical system is mainly composed of a catadioptric system using a mirror.

The control unit may be configured by using a general-purpose computer, or may be configured as a dedicated computer of the fundus imaging system 500. The control unit 625 may be configured separately from or integrally configured with an imaging unit including an OCT optical system, an SLO optical system, an anterior eye observation optical system, and a fixative lamp optical system. ..

First, the OCT optical system of the fundus imaging system 500 will be described. The light source 601 is a light source for generating light (low coherent light). An SLD (Super Luminescent Diode) is used as the light source 601. The center wavelength is 830 nm and the band is 50 nm. Although SLD was selected as the type of light source here, ASE (Amplified Spontaneous Emission) or the like can also be used as long as low coherent light can be emitted. In addition, near-infrared light is suitable for the wavelength in view of measuring the eye. Further, since the wavelength affects the lateral resolution of the obtained tomographic image, it is desirable that the wavelength is as short as possible, and here, it is set to 830 nm. Other wavelengths may be selected depending on the measurement site to be observed. Further, the wider the wavelength band, the better the resolution in the depth direction (vertical resolution). Generally, when the center wavelength is 830 nm, the vertical resolution is 6 μm in the 50 nm band and 3 μm in the 100 nm band.

The light emitted from the light source 601 is guided to the optical coupler 631 which is an optical dividing means through the single mode fiber 630-1, and is divided by the optical coupler 631 at an intensity ratio of 90:10. The reference light 605 and the OCT measurement light 606, respectively. It becomes. The ratio of division is not limited to this, and an appropriate one is selected according to the object to be inspected.

Next, the optical path of the reference light 605 will be described. The reference light 605 divided by the optical coupler 631 is guided to the lens 635-1 through the single mode fiber 630-2 and adjusted to be parallel light having a beam diameter of 2 mm. Next, the reference light 605 passes through the dispersion compensating glass 615 and is guided to the mirror 614-16 which is a reference mirror by the mirrors 614-2 to 3. Here, a planar mirror is used as a reference mirror. The light reflected by the mirror 614-16 is again sequentially reflected by the mirror 614-3 and the mirror 614-2, passes through the dispersion compensating glass 615, and is guided to the optical coupler 631.

The dispersion compensating glass 615 compensates for the dispersion of the reference light 605 when the OCT measurement light 606 reciprocates between the eye to be inspected 607 and the lens 635-4.

The mirror 614-16 is arranged on the electric stage 617-1 and constitutes the optical path length adjusting means in the present embodiment. The electric stage 617-1 can be moved in the direction shown by the arrow, and the optical path length of the reference light 605 can be adjusted. Here, the moving range of the electric stage 617-1 is set to 350 mm. The electric stage 617-1 is controlled by the control unit 625.

Next, the optical path of the OCT measurement light 606 will be described. The OCT measurement light 606 divided by the optical coupler 631 is guided to the lens 635-4 via the single mode fiber 630-4 and adjusted to be parallel light having a beam diameter of 4 mm.

Next, the OCT measurement light 606 passes through the dichroic mirror 658-5 and the beam splitter 661-1, is reflected by the mirrors 614-5 to 6, and is incident on the deformable mirror 659 which is the aberration correction means in the present embodiment. .. Here, the deformable mirror 659 freely deforms the mirror shape of the aberrations of the OCT measurement light 606 and the OCT return light 608 based on the aberration detected by the wavefront sensor 655 which is the aberration measuring means in the present embodiment. It is a mirror device that corrects with.

Here, a deformable mirror is used as the wavefront correction device, but it is sufficient if the aberration can be corrected, and a spatial optical phase modulator using a liquid crystal display or the like can also be used. Further, here, a Shack-Hartmann type wavefront sensor is used as the wavefront sensor. The deformable mirror 659 and the wavefront sensor 655 are controlled by the control unit 625.

The OCT measurement light 606 is reflected by the mirrors 614-7 to 8 and is incident on the dichroic mirror 658-3. Here, the dichroic mirrors 658-3 to 4 reflect the light having the wavelength of the light source 601 and transmit the light having the wavelength of the light source 602. The OCT measurement light 606 reflected by the dichroic mirror 658-3 is incident on the X scanner 620. The center of the OCT measurement light 606 is adjusted to coincide with the center of rotation of the X scanner 620, and scans on the retina 627 in the direction perpendicular to the optical axis. Here, a galvano mirror is used as the X scanner 620.

The OCT measurement light 606 reflected by the X scanner 620 is reflected by the dichroic mirror 658-4, and is sequentially reflected by the mirrors 614-9 to 12.

The mirrors 614-11 to 614-12 are arranged on the electric stage 617-2, and constitute the first focusing means in the present embodiment. The electric stage 617-2 can be moved in the direction shown by the arrow, and the focus position of the OCT measurement light 606 can be adjusted. This makes it possible to correspond to the diopter of the eye to be inspected 607. Here, the moving range of the electric stage 617-2 is set to 160 mm, which corresponds to the diopter range of -12D to + 7D of the eye to be inspected 607. The electric stage 617-2 can be controlled by the control unit 625. The first focusing means is a badal optical system composed of reflective optical systems of mirrors 614-11 to 12. By using the reflected optical system, it is possible to prevent unnecessary stray light from entering the wavefront sensor, and it is possible to perform aberration measurement and aberration correction with higher accuracy.

The OCT measurement light 606 reflected by the mirror 614-12 is reflected by the mirrors 614-13 to 14 and is incident on the Y scanner 621. The center of the OCT measurement light 606 is adjusted to coincide with the center of rotation of the Y scanner 621, and scans on the retina 627 in the direction perpendicular to the optical axis and the scanning direction of the X scanner 620. Here, a galvano mirror is used as the Y scanner 621.

The OCT measurement light 606 reflected by the Y scanner 621 is reflected by the mirror 614-15, passes through the dichroic mirrors 658-1 to 2, and is incident on the eye to be inspected 607. The X scanner 620, the Y scanner 621, and the mirrors 614-9 to 15 function as an optical system for scanning the retina 627 using the OCT measurement light 606. The optical system scans the retina 627 using the OCT measurement light 606 with the vicinity of the pupil 626 as a fulcrum.

When the OCT measurement light 606 is incident on the eye to be inspected 607, it is reflected and scattered by the retina 627 of the fundus, and is guided to the optical coupler 631 again as the OCT return light 608.

The reference light 605 and the OCT return light 608 are combined by the optical coupler 631 and further divided into 90:10. Then, the combined light (interference light) 642 is emitted from the single mode fiber 635-3 as spatial light, passes through the lens 635-2, and is separated for each wavelength by the transmission type grating 641. The dispersed light is focused by the lens 635-3 and illuminates the line camera 639. The intensity of light is converted into a voltage for each position (wavelength) by the line camera 639. Specifically, interference fringes in the spectral region on the wavelength axis are observed on the line camera 639. The obtained voltage signal group is converted into a digital value, and data processing is performed by the control unit 625 to form a fundus tomographic image. The formed fundus tomographic image is displayed on a monitor (not shown) by the control unit 625.

Further, a part of the OCT return light 608 split by the beam splitter 661-1 irradiates the wavefront sensor 655, and the aberration of the OCT return light 608 is measured. In the present embodiment, the beam splitter 661-1 reflects a part of the OCT return light 608 and transmits the SLO return light 610 described later. This makes it possible to selectively measure the aberration of the OCT return light 608. The wavefront sensor 655 is electrically connected to the control unit 625, and the obtained aberration is expressed by the control unit 625 using the Zernike polynomial. This indicates the aberration of the eye to be inspected 607.

Further, regarding the defocus component of the Zernike polynomial, the position of the mirrors 614-11 to 12 is controlled by using the electric stage 617-2 to correct the diopter of the eye to be inspected. For components other than defocus, the surface shape of the deformable mirror 659 can be controlled and corrected to obtain a fundus tomographic image with higher lateral resolution.

Here, mirrors 614-5 to 15 are arranged so as to be optically coupled to the pupil 626, the X scanner 620, the Y scanner 621, the wavefront sensor 655, and the deformable mirror 659, and the wavefront sensor 655 is the eye subject 607. It is possible to measure the aberration that it has.

Further, the polarizing paddle 653-1 and the polarizing paddle 635-2 can adjust the polarization states of the OCT measurement light 606 and the reference light 605. Each polarization state is adjusted to maximize the intensity of the interference fringes observed on the line camera 639.

Next, the SLO optical system will be described. The light source 602 is a light source for generating light having a wavelength different from that of the light source 601. As the light source 602, an SLD having a wavelength of 780 nm is used. Although SLD is selected as the type of light source here, LD (Laser Diode) or the like can also be used.

The light emitted from the light source 602 is guided to the lens 635-5 and adjusted to be parallel light having a beam diameter of 4 mm. The light transmitted through the lens 635-5 is guided to the beam splitter 661-2, and the intensity ratio of the transmitted light and the reflected light (SLO measurement light 609) is divided by 90:10. The SLO measurement light 609 reflected by the beam splitter 661-2 passes through the focus lens 635-7 and the lens 635-8. Here, the focus lens 635-7 is arranged on the electric stage 617-3, and constitutes the second focusing means in the present embodiment. The electric stage 617-3 can be moved in the direction shown by the arrow, and the focus position of the SLO measurement light 609 can be adjusted. As a result, the focus position of the SLO measurement light 609 can be adjusted to a position different from the focus position of the OCT measurement light 606. Here, the moving range of the electric stage 617-3 is set to 10 mm, which corresponds to a diopter range of -2D to + 2D. By mainly performing the diopter correction of the eye to be inspected 607 by the first focus means, the diopter correction range of the second focus means can be suppressed to be narrow. Therefore, the moving range of the electric stage 617-3 can be narrowed with respect to the electric stage 617-2. As a result, a smaller stage can be used, which is advantageous for miniaturization of the optical system. In FIG. 1, the focus lens 635-7 is shown as a convex lens, and the lens 658-8 is shown as a concave lens, but the present invention is not limited to this. The focus lens 635-7 may be a concave lens and the lens 658-8 may be a convex lens, or both may be convex lenses to form an intermediate image between them.

The light transmitted through the focus lens 635-7 and the lens 635-8 goes to the dichroic mirror 658-5. The dichroic mirror 658-5 transmits light having a wavelength of light source 601 and reflects light having a wavelength of light source 602. The SLO measurement light 609 reflected by the dichroic mirror 658-5 passes through a common light path that shares a part with the light path of the OCT measurement light 606, and is used as a beam splitter 661-1, mirrors 614-5-6, and deformable mirror 659. , Mirror 614-7, Mirror 614-8, and incident on the dichroic mirror 658-3. Here, the dichroic mirrors 658-3 to 4 reflect the light having the wavelength of the light source 601 and transmit the light having the wavelength of the light source 602. Therefore, the SLO measurement light 609 reflected by the mirror 614-8 passes through the dichroic mirror 658-3 and is incident on the X scanner 619. The center of the SLO measurement light 609 is adjusted to coincide with the rotation center of the X scanner 619, and scans on the retina 627 of the fundus in the direction perpendicular to the optical axis.

Here, the OCT measurement light 606 and the SLO measurement light 609 are branched by the dichroic mirror 658-3, so that the X scanner 620 of the OCT measurement light 606 and the X scanner 619 of the SLO measurement light 609 are separately arranged. The scanning speed of the OCT measurement light 606 is limited by the readout speed of the line camera 639, but the scanning speed of the SLO measurement light 609 can be increased by separating the X scanner, and the frame rate for acquiring the fundus plane image can be increased. Can be raised. Here, a resonance mirror is used for the X scanner 619.

The SLO measurement light 609 reflected by the X scanner 619 passes through the dichroic mirror 658-4, passes through the common optical path with the OCT measurement light 606 again, and is incident on the eye to be inspected 607.

When the SLO measurement light 609 is incident on the eye to be inspected 607, it is reflected and scattered by the retina 627, returns as the SLO return light 610 through the optical path of the SLO measurement light 609, is reflected by the dichroic mirror 658-5, and then is reflected by the beam splitter 661. It is transparent to -2. The intensity ratio of the transmitted light (SLO return light 610) and the reflected light is 90:10. The SLO return light 610 transmitted through the beam splitter 661-2 is focused by the lens 635-6 and passes through the pinhole plate 660. The pinhole position of the pinhole plate 660 is adjusted to a position conjugate with the fundus, and acts as a confocal diaphragm that blocks unnecessary light from other than the conjugate point.

The SLO return light 610 that has passed through the pinhole is received by the light receiving element 640. Here, an APD (Avalanche Photodiode) is used as the light receiving element 640. The light received by the light receiving element 640 is converted into a voltage signal according to the light intensity. The obtained voltage signal group is converted into a digital value, data processing is performed by the control unit 625, and the fundus plane image is acquired. The light receiving element 640 and the control unit 625 form the image acquisition means in the present embodiment. The acquired fundus plane image is displayed on the monitor by the control unit 625.

Next, the fixative lamp optical system will be described. The fixative optical system consists of a dichroic mirror 658-2 and a fixative panel 657.

The dichroic mirror 658-2 reflects the visible light of the fixative panel 657 and transmits the light of the wavelengths of the light source 601 and the light source 602. As a result, the pattern displayed on the fixative panel 657 is projected onto the retina of the eye to be inspected 607 via the dichroic mirror 658-2. By displaying the desired pattern on the fixative panel 657, the fixative direction of the eye to be inspected 607 can be specified and the range of the retina to be imaged can be set. Here, an organic EL panel is used as the fixative panel 657. The fixative panel 657 is connected to the control unit 625 and is controlled by the control unit 625.

Next, the anterior eye observation optical system will be described. The anterior eye observation optical system includes a dichroic mirror 658-1, an anterior eye observation camera 656, and an anterior eye illumination light source (not shown).

The dichroic mirror 658-1 reflects the infrared light of the front eye illumination light source and transmits the visible light of the fixed-view lamp panel 657 and the light of the wavelengths of the light source 601 and the light source 602. The optical axis of the anterior eye observation camera 656 is adjusted so as to coincide with the optical axis of the OCT optical system and the SLO optical system. , XY position alignment can be performed. Further, the focus of the anterior eye observation camera 656 is adjusted so as to be in focus on the iris of the eye to be inspected 607 when it matches the working distance of the OCT optical system and the SLO optical system. Therefore, by observing the iris on the monitor and focusing on it, the Z position can be aligned. Here, an LED having a wavelength of 970 nm is used as the front eye illumination light source. Further, a CCD camera is used as the front eye observation camera 656. The front eye observation camera 656 is connected to the control unit 625 and is controlled by the control unit 625.

Next, the relationship between the imaging range of the OCT optical system and the SLO optical system in the present embodiment will be described with reference to FIG. In FIG. 2, the solid line is the shooting range of the OCT optical system, the frame of the broken line is the shooting range of the SLO optical system, and the relationship with the shooting range of the SLO optical system when one line is shot by the OCT optical system is schematically shown. Shows.

Since the Y scanner 621 is arranged in the common optical path in the OCT optical system and the SLO optical system, they are scanned simultaneously in the Y direction (vertical direction in FIG. 2). On the other hand, since the X scanner 620 of the OCT measurement light 606 and the X scanner 619 of the SLO measurement light 609 use different scanners, the shooting range in the X direction (left-right direction in FIG. 2) can be set independently. .. For example, in FIG. 2, the shooting range of the OCT optical system is set at substantially the center of the shooting range of the SLO optical system, but the relationship of the shooting range in the X direction is not limited to this. The imaging range of the OCT optical system may be arbitrarily set regardless of the imaging range of the SLO optical system.

Further, since the resonance mirror of the X scanner 619 has a higher scanning speed than the galvano mirror, the SLO measurement light 609 is scanned a plurality of times in the X direction during one Y scan.

When capturing a 3D volume image, the OCT measurement light 606 is scanned by the X scanner 620 in addition to the scan of the X scanner 619 and the Y scanner 621. As a result, the above-mentioned shooting of one line in the Y direction is repeated by changing the scan position of the X scanner 620. During this period, the SLO optical system acquires a fundus plane image (two-dimensional image).

The relationship between the shooting range of the OCT optical system and the SLO optical system is not limited to this. The Y scanner of the OCT measurement light 606 and the Y scanner of the SLO measurement light 609 may be used as separate scanners, and the X scanner may be arranged in a common optical path. In this case, the OCT measurement light 606 and the SLO measurement light 609 are simultaneously scanned in the X direction (left-right direction in FIG. 2). Further, the X scanner and the Y scanner may be separately arranged in the OCT optical system and the SLO optical system, respectively. In this case, the OCT measurement light 606 and the SLO measurement light 609 can be scanned independently in both the X direction and the Y direction.

Next, a method of positioning (tracking) using a fundus plane image will be described.

When a tomographic image of one line at the same position is taken multiple times with the OCT optical system, the fundus plane image acquired by the SLO optical system at the time of the first shooting is used as a reference image, and the second and subsequent images that are the target images for misalignment detection are used. The amount of misalignment of the fundus plane image is calculated. The amount of misalignment can be calculated by image processing such as pattern matching. Then, by controlling the X scanner 620 and the Y scanner 621 so as to correct the calculated misalignment amount, fundus tracking, that is, correction of the irradiation position of the OCT measurement light and the SLO measurement light on the fundus is performed. Can be done. The acquired multiple line tomographic images at the same position can be used for noise reduction processing of the tomographic images by superposition.

This fundus tracking method is the same when acquiring a 3D volume image with the OCT optical system. In this case, as described above, the OCT optical system repeatedly acquires a tomographic image of one line in the Y direction while changing the position in the X direction. At this time, using the fundus plane image (two-dimensional image) acquired in the first time (first line) as a reference image, the amount of position shift of the fundus plane image after the second time (second line) which is the target image for position shift detection. Is calculated and the fundus tracking is performed.

As the reference image, the entire area of the fundus plane image acquired in the first time may be used, or a part thereof may be used. By using a part of the fundus plane image, the acquisition interval of the target image can be shortened, and the control rate of the fundus tracking can be increased. This is advantageous in correcting the misalignment due to the faster movement of the fundus.

Further, here, the image size of the reference image may be set larger than the image size of the target image. In this case, while keeping the image size of the target image small to maintain the control rate, it is easy to secure a large overlapping area between the reference image and the target image even if the amount of misalignment between the reference image and the target image is large, and the position due to a large movement of the fundus. It is advantageous in correcting the deviation. If the fundus moves slowly and the fundus tracking control rate has a margin, the image size of the target image may be set larger than the image size of the reference image. Even in this case, it is advantageous for correcting the positional deviation due to the large movement of the fundus.

(Shooting procedure for fundus image shooting)
Next, with reference to the flowchart of FIG. 3, a photographing procedure for photographing the fundus in the fundus image capturing system 500 of the present embodiment will be described.

First, the examiner performs XYZ alignment of the device while observing the anterior segment of the eye to be inspected. When the examiner presses the front eye illumination light source button (not shown) displayed on the monitor, the front eye illumination light source is turned on in step S101. When the anterior eye illumination light source is turned on, the anterior segment of the eye to be inspected 607 is displayed on the monitor. As described above, since the XYZ position of the front eye observation camera 656 is adjusted, the XYZ position of the apparatus is adjusted so that the XY position and the focus (Z position) of the front eye portion displayed on the monitor are aligned. When the examiner who confirms that the alignment is completed presses the front eye illumination light source button displayed on the monitor again, the front eye illumination light source is turned off.

After turning off the front eye illumination light source, in step S102, the light source 602 of the SLO optical system is turned on in response to the examiner pressing the SLO light source button (not shown) displayed on the monitor. When the light source 602 of the SLO optical system is turned on, the control unit 625 generates a fundus plane image based on the output of the light receiving element 640 and displays it on the monitor. In step 102, the control unit 625 adjusts the rough focus according to the input of the examiner based on the fundus plane image displayed on the monitor. The control unit 625 moves the electric stage 617-2 in response to the examiner moving the focus adjustment bar (not shown) displayed on the monitor.

The electric stage 617-2 and the mirrors 614-11 to 12 are arranged in a common optical path between the OCT measurement light 606 and the SLO measurement light 609, and the OCT measurement light 606 can also be adjusted by adjusting the focus of the SLO measurement light 609. Rough focus adjustment is performed at the same time. Here, the focus position is adjusted so that the brightness of the fundus plane image is maximized. At this time, the electric stage 617-3 is controlled by the control unit 625 so as to be in a preset initial state position. Here, as an initial state, the focus positions of the OCT measurement light 606 and the SLO measurement light 609 are set to substantially coincide with each other.

When the rough focus adjustment is completed, in step S103, the examiner presses the OCT light source button (not shown) displayed on the monitor, so that the control unit 625 lights the light source 601 of the OCT device. The control unit 625 performs XY fine alignment according to the input of the examiner based on the position of the Hartmann image of the wavefront sensor 655 displayed on the monitor obtained by turning on the light source 601.

Here, the wavefront sensor 655 is adjusted so that the center position of the wavefront sensor 655 is aligned with the optical axes of the OCT optical system and the SLO optical system. Therefore, the examiner can align the OCT optical system and the SLO optical system in the X direction and the Y direction by adjusting the position of the eye to be inspected so that the Hartmann image is aligned with the center of the wavefront sensor 655.

When the XY fine alignment is completed, in step S104, the examiner presses the wavefront correction button (not shown) displayed on the monitor, and the control unit 524 starts the wavefront correction by the deformable mirror 659. Here, the control unit 625 deforms the shape of the deformable mirror 659 based on the aberration measured by the wavefront sensor 655, and corrects the aberration of the eye to be inspected other than the defocus component. The deformable mirror 659 is arranged in a common optical path between the OCT measurement light 606 and the SLO measurement light 609. As a result, the aberration of the eye to be inspected is corrected for the OCT measurement light 606, and the aberration of the eye to be inspected is also corrected for the SLO measurement light 609.

When the wavefront correction is started, in step S105, the control unit 625 performs fine focus adjustment while looking at the fundus plane image acquired by the SLO optical system. Similar to step S102, the control unit 625 moves the electric stage 617-2 to adjust the focus position in response to the examiner moving the focus adjustment bar (not shown) displayed on the monitor. Here, the focus position of the fundus plane image is adjusted so as to match the layer having many feature points of the fundus. In this embodiment, the layer is adjusted so that the photoreceptor layer is in focus as a layer having many characteristic points. The focus position of the SLO optical system is not limited to the photoreceptor layer. If the desired tracking accuracy can be achieved, the position may have other feature points such as blood vessels.

In step S106, when the contrast of the fundus plane image acquired by the SLO device is maximized by the fine focus adjustment, the control unit 625 tracks in response to the examiner pressing the tracking button (not shown) displayed on the monitor. To start. The control unit 625 functioning as the eye movement detecting means in the present embodiment calculates the amount of misalignment from the feature points of the fundus plane image acquired by the SLO optical system. Then, tracking, that is, correction of the irradiation position of the OCT measurement light and the SLO measurement light on the fundus is performed by controlling the X scanner 620 and the Y scanner 621 based on the calculated deviation amount. As a result, when a plurality of images having different focus positions are repeatedly acquired in the subsequent steps S108 to S110, the positional deviation between the plurality of images can be suppressed to be small.

When the tracking is started, in step S107, the control unit 625 adjusts the optical path length of the reference light 605 in response to the examiner moving the reference optical path length adjustment bar (not shown) displayed on the monitor. Here, the display position of the retinal layer in the fundus tomographic image is adjusted so as to match a desired position in the tomographic image display area.

After the fundus tomographic image is adjusted to the desired display position, OCT fine focus adjustment is performed in step S108. The control unit 625 moves the electric stage 617-2 to adjust the focus position in response to the examiner moving the fine focus adjustment bar (not shown) displayed on the monitor. In the adaptive optics OCT optical system with high lateral resolution, since the NA of the measured light in the fundus is large and the depth of focus is shallow, it becomes difficult to simultaneously focus over the entire depth direction of the retina. Therefore, first, the OCT fine focus adjustment is performed so that the OCT measurement light 606 is in focus on the layer at the end of the range in the depth direction to be photographed.

The relationship between the photographing range and the focus position of the OCT measurement light 606 will be described with reference to FIG. The range of Δ4 shown by the alternate long and short dash line in FIG. 4D schematically indicates the imaging range to be acquired. Here, the range from the nerve fiber layer to the retinal pigment epithelium is taken as the imaging range, where e indicates the nerve fiber layer and f indicates the retinal pigment epithelium. First, the control unit 625 adjusts the focus position of the OCT measurement light 606 to a position where the brightness near the nerve fiber layer, which is the upper end of the imaging range, is maximized (FIG. 4A). The range of Δ1 shown by the alternate long and short dash line in FIG. 4A indicates the range in which a high-luminance image can be acquired in the vicinity of the focus position of the OCT measurement light 606. In addition, the solid line of the fundus tomographic image shows the part that can be detected with high brightness because it is within the depth of focus, and the broken line shows the part that cannot be detected with high brightness because it is outside the depth of focus. In FIG. 4A, a part of the nerve fiber layer can be detected with high luminance.

Here, the OCT fine focus adjustment is performed by moving the electric stage 617-2 in which the mirrors 614-11 to 614-12, which are the first focusing means, are arranged. At this time, the electric stage 617-3 in which the focus lens 635-7, which is the second focus means arranged in the SLO dedicated optical path, is arranged, is controlled so as to operate in a direction of canceling the adjustment by the first focus means. It is controlled by unit 625. As a result, the focus position of the OCT measurement light 606 can be adjusted without changing the focus position of the SLO measurement light 609 from the position adjusted in step S105. Further, the electric stage 617-1 in which the mirrors 614-16 are arranged is controlled by the control unit 625 so as to change the optical path length by substantially the same amount as the optical path length changed by the focus adjustment by the first focusing means. This makes it possible to adjust the focus position of the OCT measurement light 606 without changing the display position in the depth direction of the fundus tomographic image.

Further, the focus lens 635-7 is arranged in the common optical path of the SLO measurement light 609 and the SLO return light 610. As a result, the focus position of the SLO measurement light 609 can be aligned with the desired position of the retina 627, and at the same time, the focus position of the SLO return light 610 from that position can be aligned with the pinhole position of the pinhole plate 660. The focus adjustment of the SLO optical system is also performed by moving the lens 635-5 arranged in the dedicated optical path of the SLO measurement light 609 and the lens 635-6 arranged in the dedicated optical path of the SLO return light 609 in the optical axis direction, respectively. be able to. However, in that case, it is necessary to control the positions of the lens 635-5 and the lens 635-6, respectively, which complicates the device configuration and control. Therefore, it is advantageous to use the focus lens 635-7 in order to simplify the device configuration and control.

After the OCT fine focus adjustment is adjusted to the desired focus position, in step S109, the control unit 625 responds to the examiner pressing the photographing button (not shown) displayed on the monitor, and the control unit 625 performs the fundus tomographic image and the fundus plane. Acquire an image. The interference light between the OCT measurement light 606 and the reference light 605 is received by the line camera 639 and converted into a voltage signal. Further, the obtained voltage signal group is converted into a digital value, and the data is stored and processed by the control unit 625. The SLO measurement light 609 is received by the light receiving element 640 and converted into a voltage signal. Further, the obtained voltage signal group is converted into a digital value, and the data is stored and processed by the control unit 625. At this time, the focus position information of the OCT measurement light 606 is saved as additional information together with the image data.

When the shooting is completed, in step S110, the control unit 625 determines whether or not the desired shooting range in the depth direction has been shot. Here, since only the image in the range of Δ1 shown in FIG. 4A can be acquired with respect to the shooting range of Δ4 shown in FIG. 4D, the process returns to the OCT fine focus adjustment in step S108.

In the OCT fine focus adjustment in step S108 (second time), the control unit 625 adjusts so as to change the focus position toward the retinal pigment epithelium side with respect to the first OCT fine focus adjustment (FIG. 4 (b)). In FIG. 4B, similarly to FIG. 4A, the range of Δ2 shown by the alternate long and short dash line indicates the range in which a high-luminance image can be acquired in the vicinity of the focus position of the OCT measurement light 606.

After the OCT fine focus adjustment is adjusted to the desired focus position, the control unit 625 acquires the fundus tomographic image and the fundus plane image in response to the examiner pressing the photographing button (not shown) displayed on the monitor. (Step S109 (second time)). At this time, the focus position information of the OCT measurement light 606 is saved as additional information together with the image data.

When the shooting is completed, the control unit 625 determines whether or not the desired shooting range in the depth direction has been shot (step S110). Here, since only the images in the range of Δ1 shown in FIG. 4A and the range of Δ2 shown in FIG. 4B can be acquired with respect to the photographing range of Δ4 shown in FIG. 4D, step S108. Return to the (third) OCT fine focus adjustment.

In the OCT fine focus adjustment in step S108 (third time), the control unit 625 adjusts so that the focus position is further changed to the retinal pigment epithelial side with respect to the second OCT fine focus adjustment (FIG. 4 (c)). .. In FIG. 4 (c), as in FIGS. 4 (a) and 4 (b), the range of Δ3 shown by the alternate long and short dash line is the range in which a high-luminance image can be acquired in the vicinity of the focus position of the OCT measurement light 606. Is shown.

After the OCT fine focus adjustment is adjusted to the desired focus position, the photographing button (not shown) displayed on the monitor is pressed to acquire the fundus tomographic image and the fundus plane image (step S109 (third time)). At this time, the focus position information of the OCT measurement light 606 is saved as additional information together with the image data.

When the photographing is completed, it is determined whether or not the desired range in the depth direction has been photographed (step S110). Here, when the ranges of Δ1, Δ2, and Δ3 shown in FIGS. 4 (a), 4 (b), and 4 (c) are combined, the entire area (nerve fiber) of the imaging range of Δ4 shown in FIG. 4 (d) is combined. Since the area from the layer to the retinal pigment epithelium) has been photographed, the imaging is completed.

The control unit 625, which is an image synthesizing means in the present embodiment, is stored together with each image from three images having different focus positions shown in FIGS. 4 (a), 4 (b), and 4 (c). The image of the portion having high brightness is extracted by using the focus position information of the OCT measurement light 606. Then, by synthesizing the images, it is possible to acquire an image having high brightness over the entire shooting range (FIG. 4 (d)).

In the present embodiment, in steps S108 to S110, the focus position of the SLO measurement light 609 is always aligned with the photoreceptor layer having many feature points in the adaptive optics SLO apparatus while the imaging is repeated at a plurality of different focus positions of the OCT measurement light 606. The plane image of the fundus is continuously acquired. By using these fundus plane images, it becomes possible to perform highly accurate fundus tracking. As a result, it is possible to acquire a wide range of images in the depth direction acquired by synthesizing three images with less distortion. Further, since the aberration fluctuation due to the movement of the focus lens 635-7 does not affect the OCT optical system, it is possible to acquire the fundus tomographic image by the adaptive optics OCT optical system while performing the aberration correction with high accuracy.

[Second Embodiment]
A second embodiment of the present invention will be described in detail below with reference to the drawings.

(Device configuration)
The fundus image acquisition system 501 as one aspect of the image capturing apparatus according to the present embodiment will be described with reference to FIG. The basic configuration of the image acquisition system 501 is the same as that of the fundus image acquisition system 500 according to the first embodiment. However, the lens 635-7, the lens 635-8, and the electric stage 617-3 arranged in the dedicated optical path of the SLO optical system of the fundus image acquisition system 500 are not arranged, and the lens 635-7', the lens 635-8', It differs in that it has an electric stage 617-3'. The lens 635-7', the lens 635-8', and the electric stage 617-3'are arranged in a dedicated optical path of the OCT optical system branched from the common optical path of the OCT optical system and the SLO optical system. The second focusing means in the above is configured.

(Procedure for taking a fundus image)
Next, in the fundus image acquisition system 501 of the present embodiment, an imaging procedure for acquiring a tomographic image of the fundus will be described. The photographing procedure of the present embodiment is the same as the photographing procedure of the first embodiment shown in FIG.

First, in steps S101 to S107, alignment, focus adjustment, wavefront correction, tracking, and reference optical path length adjustment are performed in the same manner as in the first embodiment.

Next, when the fundus tomographic image is adjusted to a desired display position, OCT fine focus adjustment is performed (step S108). In response to the examiner moving the fine focus adjustment bar (not shown) displayed on the monitor, the control unit 625 moves the electric stage 617-3'where the focus lens 635-7'is located to the focus position. Is adjusted.

Here, the focus lens 635-7'is arranged in a dedicated optical path of the OCT optical system branched from the common optical path with the SLO optical system. Therefore, by changing the position of the focus lens 635-7'on the electric stage 617-3', the focus position of the OCT optical system can be adjusted without affecting the focus state of the SLO optical system. After adjusting the position where the brightness of the desired layer is maximized by the OCT fine focus adjustment, an image is taken in the same procedure as in the first embodiment (step S109).

In the present embodiment, as in the first embodiment, in steps S108 to S110, imaging is repeated at a plurality of different focus positions of the OCT measurement light 606. During that time, the adaptive optics SLO apparatus constantly focuses on the photoreceptor layer having many feature points and acquires a fundus plane image. Then, by using those fundus plane images, it becomes possible to perform highly accurate fundus tracking. As a result, it is possible to acquire a wide range of images in the depth direction obtained by synthesizing a plurality of images having different focus positions with less distortion. Further, in the present embodiment, the optical path length does not change by the focus adjustment by the focus lens 635-7'. Therefore, it is not necessary to control the focus position of the SLO optical system in conjunction with the OCT fine focus adjustment, so that the control system can be made simpler.

[Other embodiments]
Although the preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof.

In the first and second embodiments, the focus position of the OCT measurement light 606 is adjusted while observing the fundus tomographic image, and three tomographic images having different focus positions are acquired and combined. Not limited to this. Two or four or more tomographic images may be acquired and combined depending on the width of the imaging range. Even in this case, by performing highly accurate tracking using the fundus plane image of the adaptive optics SLO device during repeated imaging, it is possible to acquire a wide range of fundus tomographic images in the depth direction with less distortion.

Further, in the first and second embodiments, the examiner operates the device to repeatedly adjust the focus position of the OCT measurement light 606 and perform imaging, but control is performed so that these processes are automatically performed. The device may be controlled by the unit 625. In this case, the examiner inputs the shooting range and the number of shots on the monitor. The control unit 625 calculates the adjustment amount of one OCT fine focus adjustment by dividing the shooting range by the number of shots. Then, when the image is acquired at a predetermined focus position and adjusted again to the next focus position, the first focus means is moved so as to adjust the focus position of the OCT optical system by the amount calculated by the control unit 625. .. Here, as for the relationship between the adjustment amount of the focus position and the movement amount of the first focus means, a table or a conversion formula may be obtained in advance from a simulation or the like using design value data. The movement amount of the first focus means can be calculated from the adjustment amount of the focus position by using the table or the conversion formula obtained in advance.

Further, in order to determine the shooting conditions, the range in the depth direction (the depth of focus of the device) in which an image having high brightness can be acquired near the focus position of the adaptive optics OCT device may be obtained in advance by simulation or actual measurement. .. In this case, the examiner inputs the shooting range on the monitor. The control unit 625 calculates the number of shots by dividing the shooting range by the value of the depth of focus of the device. Then, when the image is acquired at a predetermined focus position and adjusted again to the next focus position, the first focus means is adjusted so as to adjust the focus position of the OCT optical system to a position shifted by the range of the focus depth of the apparatus. To move.

The control unit 625 takes a picture when the OCT fine focus adjustment is completed, and controls the device so as to repeat the focus adjustment and the picture up to the input (or calculated) number of pictures taken. In this case, the operation of the examiner can be simplified, which is advantageous in shortening the time from the start of shooting to the completion of acquisition of an image in a desired shooting range. If the shooting time can be shortened, the load on the subject at the time of shooting can be reduced.

Further, in the first and second embodiments, fundus tracking is performed at the time of imaging, but it is not always necessary to perform fundus tracking in real time. In this case, in addition to the tomographic image of the fundus tomographic image acquired by the OCT optical system and the information on the focus position of the OCT optical system at the time of photographing, the plane plane image of the fundus acquired by the SLO device is stored at the same time. Positional information is extracted from the saved fundus plane image, and the alignment of multiple images and the composition of the images are performed. Even in this case, since the focus position of the SLO optical system always matches the layer having many feature points, it is advantageous to perform the alignment with high accuracy. Here, the adjustment of the focus position and the acquisition of the 3D volume image may be repeated a plurality of times, and data may be extracted and combined from the relationship between the focus position at the time of shooting and the shooting position on the fundus. For example, from a plurality of images having different focus positions and shooting positions, a plurality of tomographic images having different focus positions at predetermined positions are extracted, and high-brightness tomographic image data is extracted from the focus position information of each image. It may be synthesized. Even in this case, it is possible to acquire a wide range of fundus tomographic images in the depth direction with less distortion.

Further, in the first and second embodiments, the position of the electric stage 617-1 which is the reference optical path length adjusting means is in the depth direction of the fundus tomographic image while the focus position of the OCT measurement light 606 is repeatedly adjusted and photographed. The display position of is controlled so as not to change. However, the electric stage 617-1 may be controlled by the control unit 625 so that the display position of the fundus tomographic image becomes a predetermined position. In the OCT device, the smaller the difference between the optical path length of the measurement light 606 and the optical path length of the reference light 605, the higher the SN ratio of the tomographic image. Therefore, when repetitive shooting is performed at a plurality of different focus positions of the OCT measurement light 606, if the optical path length to the focus position of the OCT measurement light 606 is always close to the optical path length of the reference light 605, a wide range in the depth direction is obtained. It is advantageous to acquire an image having a high SN ratio. In FIG. 4, the upper end of the frame displaying the tomographic image is at a position where the optical path length of the measurement light 606 of the OCT device and the optical path length of the reference light 605 substantially coincide with each other. When the first shooting focuses on the range of Δ1 in FIG. 4A and the second shooting focuses on the range of Δ2 in FIG. 4B, the range of Δ2 becomes the range of Δ1. The control unit 625 controls the electric stage 617-1 to adjust the reference optical path length so as to be displayed. Further, when focusing on the range of Δ3 in FIG. 4C in the third shooting, the control unit 625 controls the electric stage 617-1 so that the range of Δ3 is displayed in the range of Δ1 as a reference optical path. Adjust the length. As a result, imaging can always be repeated at a position where the difference between the optical path length of the measurement light 606 and the optical path length of the reference light 605 is small, and a fundus tomographic image having a high SN ratio can be acquired over a wide range in the depth direction.

Further, in the first and second embodiments, rough focus adjustment (step S102) and fine focus adjustment (step S105) are performed by moving the electric stage 617-2 as the first focusing means. However, the first focusing means is not limited to the electric stage 617-2 in which the mirrors 614-11 to 12 (badal optical system) are arranged. In particular, the fine focus adjustment may be performed by deforming the deformable mirror 659 in which a part of the optical paths of the OCT optical system and the SLO optical system are arranged in a common optical path. In this case, the deformable mirror is controlled by the control unit 625 so as to correct the defocus component of the wavefront aberration. Then, the control unit 625 controls the deformable mirror 659 by giving an offset of the defocus component to the target shape of the deformable mirror 659 based on the measured value of the wavefront sensor 655. In this case, since the optical path length does not change due to the focus adjustment of the OCT optical system, the control of the electric stage 617-1 in which the mirror 614-16 is arranged becomes easy.

Further, in the first embodiment, the OCT fine focus adjustment (step S108) is performed by moving the electric stage 617-2 as the first focusing means. However, the OCT fine focus adjustment may be performed by deforming the deformable mirror 659 arranged in the common optical path of the OCT optical system and the SLO optical system. In this case as well, the deformable mirror is controlled by the personal computer 625 so as to correct the defocus component of the wavefront aberration. Then, the control unit 625 controls the target shape of the deformable mirror 659 based on the measured value of the wavefront sensor 655 by giving an offset of the defocus component. At this time, the electric stage 617-3, which is the second focusing means, is controlled so as to cancel the offset amount of the defocus component given to the deformable mirror 659. As a result, the focus position of the OCT optical system can be changed while maintaining the focus position of the SLO optical system.

The rough focus adjustment (step S102), the fine focus adjustment (step S105), and the OCT fine focus adjustment (step S108) may all be performed by the deformable mirror 659. In this case, the badal optical system does not necessarily have to be arranged, and the deformable mirror 659 is used as the first focusing means for adjustment.

Further, in the first embodiment and the second embodiment, the electric stage 617-2 in which the mirrors 614-11 to 12 (badal optical system) are arranged is moved to perform rough focus adjustment (step S102) and fine focus adjustment. When (step S105) is performed, the position of the stage 617-1 which is the reference optical path length adjusting means is fixed. However, the control unit 625 may control the electric stage 617-1 to move in conjunction with the focus adjustment by the Badal optical system. In this case, the control unit 625 has an electric stage 617-1 in which the mirror 614-16 is arranged so that the optical path length changes by substantially the same amount as the amount of change in the optical path length when the electric stage 617-2 is moved by focus adjustment. To move. As a result, the focus position can be adjusted while keeping the optical path length of the OCT measurement light 606 and the optical path length of the reference light 605 substantially the same. Therefore, the amount of movement of the electric stage 617-1 when the reference optical path length is adjusted in step S107 of the first embodiment and S207 of the second embodiment can be suppressed to a small size. If the amount of movement of the electric stage 617-1 is small, the adjustment time can be shortened, and the total shooting time from the start of processing to the completion of shooting can be shortened, so that the burden on the subject can be reduced. ..

In the above-described embodiment, the case where the object to be inspected is an eye is described, but the present invention can also be applied to an object to be inspected such as skin or an organ other than the eye. In this case, the present invention has an aspect as a medical device such as an endoscope other than the ophthalmologic imaging apparatus. Therefore, it is preferable that the present invention is grasped as an image processing apparatus exemplified by the ophthalmologic photographing apparatus, and the eye to be inspected is grasped as one aspect of the object to be inspected.

The present invention can also be achieved by configuring the device as follows. That is, a recording medium (or storage medium) in which a program code (computer program) of software that realizes the functions of the above-described embodiment is recorded may be supplied to the system or device. Further, not only the aspect of the recording medium but also a computer-readable recording medium may be used. Then, the computer (or CPU or MPU) of the system or device reads and executes the program code stored in the recording medium. In this case, the program code itself read from the recording medium realizes the function of the above-described embodiment, and the recording medium on which the program code is recorded constitutes the present invention. The embodiment can also be realized by a circuit (for example, an ASIC) that realizes one or more functions.

Claims (7)

An OCT optical system that irradiates the eye to be inspected with OCT measurement light and receives interference light between the OCT return light and the reference light from the eye to be inspected to acquire a tomographic image.
An SLO optical system that irradiates the eye to be inspected with SLO measurement light and receives SLO return light from the eye to be inspected to acquire a planar image.
A common optical path that shares at least a part of the optical path of the OCT optical system and the optical path of the SLO optical system.
A first focusing means provided in the common optical path, and a second focusing means provided in at least one of the optical path of the SLO optical system or the optical path of the OCT optical system branched from the common optical path.
It has a first focusing means and a control means for controlling the second focusing means.
When the control means acquires a plurality of tomographic images having different focus positions of the OCT measurement light, the control means adjusts the focus position of the OCT measurement light to the respective focus positions of the plurality of tomographic images, and said. An image capturing apparatus comprising controlling the first focusing means and the second focusing means so that the focus position of the SLO measurement light maintains a predetermined focus position. The image capturing apparatus according to claim 1, further comprising an image synthesizing means for acquiring one tomographic image by synthesizing a plurality of tomographic images having different focus positions. Using the plane image acquired based on the SLO return light, the detection means for detecting the movement of the eye to be inspected and the detection means.
The image capturing apparatus according to claim 1 or 2, further comprising a correction means for correcting the irradiation position of the OCT measurement light based on the movement of the eye to be inspected detected by the detection means. Further, the scanning means provided in the common optical path and scanning the OCT measurement light and the SLO measurement light with the eye to be inspected is provided.
The image photographing apparatus according to claim 3 , wherein the correction means corrects the irradiation position by using the scanning means. Further, it has an adjusting means for adjusting the optical path length provided in the optical path of the reference light.
The first focusing means is a means for changing the focus position by changing the optical path length.
The image capturing apparatus according to any one of claims 1 to 4, wherein the adjusting means adjusts the optical path length of the reference light according to the adjustment of the focus position. An aberration measuring means for measuring the aberration of the OCT return light,
The image capturing apparatus according to any one of claims 1 to 5, further comprising an aberration correcting means for correcting the aberration measured by the aberration measuring means, which is provided in the common optical path. An OCT optical system that irradiates the eye to be inspected with OCT measurement light and receives interference light between the OCT return light and the reference light from the eye to be inspected to acquire a tomographic image.
An SLO optical system that irradiates an eye to be inspected with SLO measurement light and receives SLO return light from the eye to be inspected to acquire a planar image.
A common optical path that shares at least a part of the optical path of the OCT optical system and the optical path of the SLO optical system.
A first focusing means provided in the common optical path, and a second focusing means provided in at least one of the optical path of the SLO optical system or the optical path of the OCT optical system branched from the common optical path.
A control method for an image capturing apparatus having a control means for controlling the first focus means and the second focus means.
When a plurality of tomographic images having different focus positions of the OCT measurement light are acquired by the control means, the focus positions of the OCT measurement light are aligned with the respective focus positions of the plurality of tomographic images, and the above. A control method for an image capturing apparatus, characterized in that the first focusing means and the second focusing means are controlled so that the focus position of the SLO measurement light maintains a predetermined focus position.

Images