Ophthalmic device and control method thereof

Abstract

To provide a new technology to identify an optimum focusing state with good reproducibility by a simple configuration.SOLUTION: An ophthalmologic device includes a projection part, an acquisition part, and an identification part. The projection part projects pattern light of a projection shape extending in a first direction onto an eye to be examined. The acquisition part acquires a light reception image corresponding to a shape of an opening extending in the first direction on the basis of a detection result of return light detection. The identification part identifies a focusing state of the pattern light on the basis of a brightness distribution in a second direction intersecting with the first direction in the acquired one or more light reception images. The projection part projects the pattern light so that the pattern light is projected on a projection position relatively moved in the second direction with respect to a position of the opening on a detection surface of an image sensor on a light reception side. The identification part identifies the focusing state on the basis of the brightness distribution acquired by relatively moving the projection position with respect to the position of the opening on the detection surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an ophthalmic apparatus and a control method thereof. [Background technology]

[0002] In recent years, eye examinations using ophthalmic devices have been performed for screening. Such ophthalmic devices are expected to be applied to self-examination, and therefore further miniaturization and weight reduction are desired.

[0003] For example, Patent Documents 1 and 2 disclose an ophthalmic apparatus configured to illuminate a subject's eye in a pattern using slit light and detect the return light with a CMOS (Complementary Metal Oxide Semiconductor) image sensor. This ophthalmic apparatus can obtain an image of the subject's eye with a simple configuration by adjusting the illumination pattern and the timing of light reception by the CMOS image sensor.

[0004] In this type of ophthalmic device, as in other ophthalmic devices, a pattern illumination is performed when the focus state of the slit light is optimal, thereby enabling an image with higher resolution to be obtained. Patent Documents 1 and 2 disclose a method of driving a focusing mechanism using the amount of reflected light of illumination light from the subject's eye. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 7,831,106 [Patent Document 2] U.S. Patent No. 8,237,835 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the amount of reflected light of the illumination light from the subject's eye changes depending on the condition of the subject's eye or the irradiation position of the illumination light. Therefore, depending on the subject's eye, the amount of reflected light of the illumination light may be small, making it difficult to move the focal position of the slit light to an optimal position. In other words, it is difficult to achieve an optimal focusing state with good reproducibility.

[0007] The present invention has been made to solve such problems, and has an object to provide a new technique for identifying an optimal focusing state with good reproducibility using a simple configuration. [Means for solving the problem]

[0008] A first aspect of some embodiments is an ophthalmic device that includes a projection unit that projects pattern light of a projection shape extending at least in a first direction onto a test eye, an acquisition unit that acquires a received light image corresponding to an aperture shape extending at least in a second direction intersecting the first direction based on a detection result of return light of the pattern light from the test eye, and an identification unit that identifies a focus state of the pattern light based on a luminance distribution of the received light image.

[0009] A second aspect of some embodiments is an ophthalmic device that includes a projection unit that projects pattern light of a projection shape extending at least in a first direction onto a test eye, an acquisition unit that acquires a received light image corresponding to an aperture shape extending at least in the first direction based on a detection result of return light of the pattern light from the test eye, and an identification unit that identifies a focus state of the pattern light based on a luminance distribution in a second direction intersecting the first direction in one or more received light images acquired by the acquisition unit.

[0010] In a third aspect of some embodiments, in the first or second aspect, the determination unit includes a control unit that determines a focus control content of the pattern light based on a luminance distribution in the second direction in the received light image, and performs focus control of the pattern light based on the determined focus control content.

[0011] In a fourth aspect of some embodiments, in the third aspect, the control unit performs the focusing control so that a bright portion or a dark portion moves to a predetermined position.

[0012] A fifth aspect of some embodiments is the third or fourth aspect, which includes a focusing mechanism arranged in the optical path of the pattern light and the return light, and the control unit controls the focusing mechanism based on the identified focusing control content.

[0013] In a sixth aspect of some embodiments, in any one of the first to fifth aspects, the projection unit includes a projector that outputs pattern light whose projection shape is changeable.

[0014] In a seventh aspect of some embodiments, in the sixth aspect, the projection unit outputs pattern light of a first projection shape for identifying the focus state, and after focus control of the pattern light, outputs pattern light of a second projection shape different from the first projection shape, and the acquisition unit acquires a received light image based on a detection result of the return light of the pattern light of the second projection shape.

[0015] In an eighth aspect of some embodiments, in any one of the first to seventh aspects, the acquisition section includes an image sensor that detects the return light, and acquires the received-light image by a rolling shutter method.

[0016] A ninth aspect of some embodiments is a control method for an ophthalmic device, including a projection step of projecting pattern light of a projection shape extending at least in a first direction onto a test eye, an acquisition step of acquiring a received light image corresponding to an aperture shape extending at least in a second direction intersecting the first direction based on a detection result of return light of the pattern light from the test eye, and an identification step of identifying a focus state of the pattern light based on a luminance distribution of the received light image.

[0017] A tenth aspect of some embodiments is a control method for an ophthalmic device, including a projection step of projecting pattern light of a projection shape extending at least in a first direction onto a test eye, an acquisition step of acquiring a received light image corresponding to an aperture shape extending at least in the first direction based on a detection result of return light of the pattern light from the test eye, and an identification step of identifying a focus state of the pattern light based on a luminance distribution in a second direction intersecting the first direction in one or more received light images acquired in the acquisition step.

[0018] In an eleventh aspect of some embodiments, in the ninth or tenth aspect, the identification step includes a control step of identifying a focus control content of the pattern light based on a luminance distribution in the second direction in the received light image, and performing focus control of the pattern light based on the identified focus control content.

[0019] In a twelfth aspect of some embodiments, in any of the ninth to eleventh aspects, the projection step includes a first projection step of outputting pattern light of a first projection shape for identifying the focus state, and a second projection step of outputting pattern light of a second projection shape different from the first projection shape after focus control of the pattern light, and the acquisition step includes a first acquisition step of acquiring a received light image corresponding to the opening shape based on a detection result of return light of the pattern light of the first projection shape projected in the first projection step, and a second acquisition step of acquiring a received light image based on a detection result of return light of the pattern light of the second projection shape projected in the second projection step.

[0020] In a thirteenth aspect of some embodiments based on any one of the ninth to twelfth aspects, the acquiring step acquires the received-light image by a rolling shutter method based on a detection result of the return light.

[0021] The configurations according to the above-described multiple aspects can be combined in any desired manner. Effect of the Invention

[0022] According to the present invention, it is possible to provide a new technique for identifying an optimal focusing state with good reproducibility using a simple configuration. [Brief description of the drawings]

[0023] [Figure 1] 1 is a schematic diagram illustrating an example of the configuration of an ophthalmologic apparatus according to an embodiment. [Diagram 2] 1 is a schematic diagram illustrating an example of the configuration of an ophthalmologic apparatus according to an embodiment. [Diagram 3] 1 is a schematic diagram illustrating an example of the configuration of an ophthalmologic apparatus according to an embodiment. [Figure 4] 4A to 4C are diagrams illustrating the operation of the ophthalmologic apparatus according to the embodiment. [Figure 5A] 4A to 4C are diagrams illustrating the operation of the ophthalmologic apparatus according to the embodiment. [Figure 5B] 4A to 4C are diagrams illustrating the operation of the ophthalmologic apparatus according to the embodiment. [Figure 5C] 4A to 4C are diagrams illustrating the operation of the ophthalmologic apparatus according to the embodiment. [Figure 6] FIG. 4 is a flow diagram of an example of the operation of the ophthalmologic apparatus according to the embodiment. [Figure 7] FIG. 13 is a schematic diagram illustrating an example of the configuration of an ophthalmologic apparatus according to a modified example of the embodiment. [Figure 8] 10A to 10C are diagrams illustrating the operation of an ophthalmologic apparatus according to a modified example of an embodiment. [Figure 9] 10A to 10C are diagrams illustrating the operation of an ophthalmologic apparatus according to a modified example of an embodiment. [Figure 10A] 10A to 10C are diagrams illustrating the operation of an ophthalmologic apparatus according to a modified example of an embodiment. [Figure 10B] 10A to 10C are diagrams illustrating the operation of an ophthalmologic apparatus according to a modified example of an embodiment. [Figure 10C] 10A to 10C are diagrams illustrating the operation of an ophthalmologic apparatus according to a modified example of an embodiment. [Figure 11] FIG. 11 is a flowchart of an operation example of an ophthalmologic apparatus according to a modified example of an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] An example of an embodiment of an ophthalmic apparatus and a control method thereof according to the present invention will be described in detail with reference to the drawings. Note that the contents of the documents described in this specification can be appropriately used as the contents of the following embodiment.

[0025] The ophthalmic apparatus according to the embodiment includes a projection system that projects a pattern light onto the subject's eye and a light receiving system that receives return light of the pattern light from the subject's eye, and is capable of acquiring an image of the fundus of the subject's eye based on the result of receiving the return light obtained by the light receiving system. In some embodiments, the ophthalmic apparatus acquires an image of the anterior segment of the subject's eye using a configuration similar to that described above.

[0026] For example, the projection system projects a slit-shaped (line-shaped) pattern light extending at least in a first direction onto the subject's eye. The ophthalmic apparatus obtains a received-light image corresponding to an opening shape extending at least in a second direction from the result of receiving the return light obtained by the light receiving system, and identifies the focusing state of the pattern light based on the luminance distribution in the second direction in the received-light image. Here, the second direction is a direction intersecting with the first direction. In some embodiments, the second direction is different from a direction perpendicular to the first direction.

[0027] In this specification, the "direction" of the pattern light, the "direction" of the aperture shape or the received light image, and the aperture direction do not mean the direction at each position in the absolute coordinate system, but rather mean the direction on a specified optical surface (for example, the light receiving surface in a light receiving system).

[0028] [Optical system configuration] 1 to 3 show block diagrams of a configuration example of an ophthalmic apparatus according to an embodiment. Figs. 1 and 2 show block diagrams of a configuration example of an optical system of an ophthalmic apparatus 1 according to an embodiment. Fig. 3 shows a block diagram of a configuration example of a control system of the ophthalmic apparatus 1. In Figs. 1 to 3, similar parts are given the same reference numerals and descriptions thereof will be omitted as appropriate.

[0029] The ophthalmic apparatus 1 projects a pattern light onto the subject's eye E, receives the return light to specify the focus state of the pattern light, and performs focus control based on the specified focus state. After the focus control, the ophthalmic apparatus 1 projects a pattern light onto the subject's eye E again, and receives the return light to obtain an image of the subject's eye E (fundus image).

[0030] The ophthalmic apparatus 1 includes a projection system 10, a light receiving system 20, an image processing unit 30, and an image output unit 40.

[0031] The ophthalmic apparatus 1 projects pattern light onto the subject's eye E in a focus control mode for performing focus control and in an imaging mode for performing imaging, and obtains a received-light image in each mode.

[0032] [Focus control mode] The projection system 10 projects a pattern light for focus control, which has a projection shape extending at least in a direction (hereinafter, sometimes referred to as an aperture crossing direction) intersecting with the aperture direction (a direction corresponding to the aperture direction), onto the subject's eye E. The light receiving system 20 receives return light of the pattern light projected onto the subject's eye E by the projection system 10. The image processing unit 30 acquires a received light image corresponding to at least the aperture shape extending in the aperture direction from the result of receiving the return light by the light receiving system 20. The image processing unit 30 specifies the focus state (whether or not the pattern light is in focus) based on the luminance distribution in the aperture crossing direction in the received light image. The image processing unit 30 can specify the control contents for a focusing mechanism described later based on the luminance distribution. A control unit described later performs focus control according to the control contents specified by the image processing unit 30 (i.e., controls the focusing mechanism described later).

[0033] [Shooting mode] After focus control, the projection system 10 sequentially projects pattern light for photography having a projection shape (e.g., slit-shaped, line-shaped) extending in the opening direction onto the subject's eye E in a direction perpendicular to the opening direction. In some embodiments, the projection shape in the focus control mode and the projection shape in the photography mode are different from each other. The light receiving system 20 receives return light of the pattern light projected onto the subject's eye E by the projection system 10. The image processing unit 30 acquires an image of the fundus of the subject's eye E from the result of receiving the return light by the light receiving system 20 by sequentially acquiring received light images corresponding to the opening shape while shifting the opening shape in a direction perpendicular to the opening direction (or the opening intersecting direction).

[0034] (Projection system 10) The projection system 10 includes a pattern light generating unit 11 , a smoothing unit 12 , and an optical system 13 .

[0035] (Pattern light generating unit 11) The pattern light generating unit 11 is controlled by a control unit described later and generates pattern light of a projection shape extending at least in the aperture intersection direction. The pattern light generating unit 11 is capable of selectively generating pattern light of two or more projection shapes and selectively projecting the pattern light onto two or more projection regions on the subject's eye E (fundus).

[0036] 2, the pattern light generating unit 11 includes a light source 11A, an optical system 11B, and a spatial light modulator 11C. An example of the pattern light generating unit 11 having such a configuration is a projector. That is, the pattern light generating unit 11 includes the light source 11A, the optical system 11B, and the spatial light modulator 11C corresponding to the type of projector. The light source 11A can be arranged at a position that is approximately optically conjugate with the imaging site of the subject's eye E (e.g., the fundus, the anterior segment).

[0037] In some embodiments, the light source 11A is a light source capable of switching between outputting light in the infrared region or near-infrared region and light in the visible region. For example, the light source 11A outputs light in the infrared region or near-infrared region when outputting a pattern light (focus indicator) for focus control in the focus control mode, and outputs light in the visible region when photographing a desired photographing site in the photographing mode.

[0038] In some embodiments, the pattern light generating unit 11 has the function of a DLP (Digital Light Processing (registered trademark)) type projector using a digital micromirror device. In this case, in a first configuration example, a single digital micromirror device is used for light in the infrared region or near-infrared region. In a second configuration example, a digital micromirror device common to the RGB color components is used for light from a white light source. In a third configuration example, a digital micromirror device is used for each RGB color component for light from a white light source.

[0039] In the first configuration example, the light source 11A includes, for example, an LED (Light Emitting Diode) light source that emits light in the infrared region or near-infrared region. The optical system 11B includes a relay optical system and an optical lens. The spatial light modulator 11C includes a digital micromirror device in which a plurality of mirror elements are arranged two-dimensionally. Each of the plurality of mirror elements can be controlled independently. The spatial light modulator 11C may include a projection lens for projecting light spatially modulated by the digital micromirror device.

[0040] In the second configuration example, the light source 11A includes a white light source or a light source capable of outputting light of each color component of RGB. The optical system 11B includes a color wheel for outputting light of each color component of RGB in a time-division manner from the light from the light source 11A, a relay optical system, and an optical lens. The spatial light modulator 11C includes a digital micromirror device in which a plurality of mirror elements are two-dimensionally arranged. The spatial light modulator 11C may include a projection lens for projecting the light spatially modulated by the digital micromirror device.

[0041] In the third configuration example, the light source 11A includes a white light source or a light source capable of outputting light of each color component of RGB. The optical system 11B includes a relay optical system and an optical lens. The spatial light modulator 11C includes a plurality of digital micromirror devices provided for each of the color components of RGB. The spatial light modulator 11C may include a projection lens for projecting the light spatially modulated by the digital micromirror devices.

[0042] In some embodiments, the pattern light generating unit 11 has the function of a reflective liquid crystal projector using LCoS (Liquid Crystal on Silicon). In this case, the light source 11A includes a white light source. The optical system 11B includes one or more reflecting mirrors, one or more dichroic mirrors, and one or more polarizing beam splitters. The spatial light modulator 11C includes a reflective liquid crystal panel for each of the RGB color components, a cross dichroic prism for synthesizing the light spatially modulated for each color component, and a projection lens for projecting the synthesized light.

[0043] In some embodiments, the pattern light generating unit 11 has the function of a transmissive liquid crystal projector. In this case, the light source 11A includes a white light source. The optical system 11B includes one or more reflecting mirrors and one or more dichroic mirrors. The spatial light modulator 11C includes a transmissive liquid crystal panel for each of the RGB color components, a cross dichroic prism for synthesizing the light spatially modulated for each color component, and a projection lens for projecting the synthesized light.

[0044] In some embodiments, the pattern light generating unit 11 has a function of a known projector using MEMS (Micro Electro Mechanical Systems).

[0045] The above projector realizes the function of a pixelated pattern light generator. Since the configuration of the above projector is well known, detailed description will be omitted. The pattern light generating unit 11 is capable of outputting pattern light (illumination light) corresponding to an illumination pattern whose shape and projection position can be arbitrarily changed.

[0046] The pattern light generating unit 11 is controlled by a control unit described later and generates pattern light of an arbitrary projection shape. The projection shape can be set by the user using, for example, an operation unit described later. When the user specifies a shape pattern, an outer shape, a size, and the like using the operation unit, the control unit can specify an illumination pattern based on the specified shape pattern, and control the spatial light modulator 11C based on the specified illumination pattern.

[0047] (Smoothing section 12) The smoothing unit 12 smoothes the pattern light (light amount distribution of the pattern light) generated by the pattern light generating unit 11 so that the light amount distribution is diffused at least in the aperture direction (the light amount distribution spreads at least in the aperture direction). That is, the smoothing unit 12 smoothes the pattern light so that the diffusion characteristics in the aperture direction and the aperture crossing direction are different. Specifically, the transmission angle θ1 of the transmitted light with respect to a predetermined incidence angle θ0 for the aperture direction component of the pattern light is larger than the transmission angle θ2 of the transmitted light with respect to a predetermined incidence angle θ0 for the aperture crossing direction component of the pattern light.

[0048] The smoothing unit 12 can be placed at a position that is approximately optically conjugate with the imaging site of the subject's eye E (for example, the fundus, the anterior segment).

[0049] In some embodiments, the smoothing section 12 includes a diffusion filter (optical low-pass filter). In some embodiments, the smoothing section 12 includes a birefringent plate having birefringence.

[0050] (Optical system 13) The optical system 13 includes a relay optical system for relaying the pattern light smoothed by the smoothing unit 12. In some embodiments, the optical system 13 further includes a collimator lens and an optical scanner. In this case, the optical scanner is capable of deflecting the pattern light under the control of a control unit described later.

[0051] The pattern light that has passed through the optical system 13 is reflected by the optical multiplexer / demultiplexer 50 and guided to the optical system 51 .

[0052] (Optical multiplexer / demultiplexer 50) The optical multiplexer / demultiplexer 50 guides the light from the projection system 10 to the optical system 51, and also guides the light from the optical system 51 to the light receiving system 20. The function of such an optical multiplexer / demultiplexer 50 can be realized by a beam splitter or a dichroic mirror.

[0053] (Optical system 51) The optical system 51 is disposed between the optical multiplexer / demultiplexer 50 and the subject's eye E. The optical system 51 includes a focusing mechanism 52. In some embodiments, the optical system 51 further includes an objective lens disposed between the focusing mechanism 52 and the subject's eye E. In some embodiments, the optical system 51 includes a front lens for moving the focal position of the pattern light to the vicinity of the anterior segment. In this case, the front lens is provided so as to be insertable into and detachable from the optical path of the pattern light.

[0054] Examples of the focusing mechanism 52 include a focusing lens that can move along the optical axis direction (the direction of the optical path of the pattern light), a liquid lens whose refractive index can be changed, a liquid crystal lens whose refractive index can be changed, and an objective lens that can move along the optical axis direction.

[0055] The focusing lens or the objective lens can be moved automatically or manually in the optical axis direction. For example, the ophthalmic device 1 includes a moving mechanism that moves at least one of the focusing lens and the objective lens in the optical axis direction, and the control unit controls the moving mechanism to move at least one of the focusing lens and the objective lens in the optical axis direction, thereby performing focusing control. Also, for example, the user can manually adjust the focus state by operating the moving mechanism to move at least one of the focusing lens and the objective lens in the optical axis direction.

[0056] Furthermore, the control unit can perform focusing control by controlling the liquid lens or liquid crystal lens to change the refractive index.

[0057] The pattern light from the projection system 10 reflected by the optical multiplexer / demultiplexer 50 is projected onto the subject's eye E via the optical system 51. The return light of the pattern light from the subject's eye E passes through the optical system 51, is reflected by the optical multiplexer / demultiplexer 50, and is guided to the light receiving system 20.

[0058] (Light receiving system 20) The light receiving system 20 includes an optical system 21 and an image sensor 22 .

[0059] (Optical system 21) Return light of the pattern light from the subject's eye reflected by the optical multiplexer / demultiplexer 50 is incident on the optical system 21. The optical system 21 includes an imaging lens that forms an image of the return light on a detection surface of the image sensor 22. In some embodiments, the optical system 21 further includes a relay optical system for relaying the return light.

[0060] (Image Sensor 22) The image sensor 22 realizes a function as a pixelated light receiver. In this embodiment, the image sensor 22 includes a CMOS image sensor. That is, the image sensor 22 includes a plurality of photodiodes arranged two-dimensionally, a plurality of vertical signal lines, and a horizontal signal line. The plurality of vertical signal lines are provided for each group of photodiodes in the vertical direction. Each vertical signal line is selectively electrically connected to a group of photodiodes in which a charge corresponding to the light reception result is accumulated. The horizontal signal line is selectively electrically connected to the plurality of vertical signal lines. As a result, the photodiodes provided for each pixel accumulate charges corresponding to the light reception result of the return light, and the accumulated charges are read out, for example, for each group of photodiodes in the horizontal direction. That is, a voltage corresponding to the charge accumulated in each photodiode is supplied to the vertical signal line for each line in the horizontal direction. The plurality of vertical signal lines are selectively electrically connected to the horizontal signal line. The light reception results of the plurality of photodiodes arranged two-dimensionally are read out by performing the above-mentioned read operation for each horizontal line in the vertical direction.

[0061] The detection surface of the image sensor 22 can be arranged at a position that is approximately optically conjugate with a photographing portion (e.g., a fundus or an anterior segment) of the subject's eye E. That is, the detection surface of the image sensor 22 can be arranged at a position that is approximately optically conjugate with the light source 11A.

[0062] Such read control over the image sensor 22 can be executed under the control of a control unit, which will be described later.

[0063] The control unit can also read out the result of receiving the return light from the image sensor 22 using a so-called rolling shutter method. This allows a light receiving image corresponding to a desired aperture shape to be obtained by performing readout control corresponding to the desired aperture shape. Such control is disclosed, for example, in the specification of U.S. Patent No. 8,237,835.

[0064] Furthermore, the control unit can sequentially generate slit-shaped (line-shaped) pattern light extending at least in the opening direction in a direction perpendicular to the opening direction by controlling the pattern light generating unit 11. As disclosed in U.S. Pat. No. 8,237,835 and the like, the control unit synchronizes the timing of generating the pattern light by the pattern light generating unit 11 with the timing of reading the result of receiving the return light from the image sensor 22 in a rolling shutter system. This makes it possible to obtain an image of the subject's eye with a simple configuration.

[0065] (Image processing unit 30) The image processing unit 30 performs various image processing and analysis processing on the received-light image obtained by the image sensor 22. The image processing includes a noise removal process for the received-light image and a brightness correction process for making it easier to identify a specific part depicted in the received-light image. The analysis processing includes a process for specifying the focusing state, which will be described later, and a process for specifying the control content for performing the focusing control, which will be described later.

[0066] The image processing unit 30 is capable of acquiring a received light image corresponding to an arbitrary aperture shape based on the light reception result read out from the image sensor 22 by the rolling shutter method under control of the control unit. The image processing unit 30 acquires a received light image of an aperture shape corresponding to the pattern light of the projection shape for focus control (first projection shape), and also acquires a received light image of an aperture shape corresponding to the pattern light of the projection shape for shooting (second projection shape). This allows the image processing unit 30 to acquire a received light image corresponding to the aperture shape for focus control, and to create a received light image corresponding to the aperture shape (same or different from the aperture shape during focus control) after focus control.

[0067] In some embodiments, the optical system 21 includes an aperture stop disposed between the imaging lens and the image sensor 22. In this case, the return light that has passed through the aperture stop is imaged on the detection surface of the image sensor 22. Therefore, the image processing unit 30 can obtain a received light image corresponding to the aperture shape of the aperture stop based on the received light result read out from the image sensor 22 by the global shutter method under the control of the control unit.

[0068] Furthermore, the image processor 30 specifies the focusing state of the pattern light based on the luminance distribution in the aperture direction (or the aperture crossing direction) in the acquired received light image. In some embodiments, the focusing state indicates whether or not the focal position of the pattern light substantially coincides with the desired illumination position.

[0069] Furthermore, the image processing unit 30 specifies the amount and direction of movement of the focal position of the pattern light based on the luminance distribution in the aperture intersection direction in the acquired received light image.

[0070] The detailed operation of the image processing unit 30 will be described later.

[0071] The image processing unit 30 includes a processor, and performs processing according to a program stored in a storage unit or the like to realize the above functions.

[0072] In this specification, the term "processor" refers to a circuit such as a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), or a field programmable gate array (FPGA)). The processor realizes the functions according to the embodiment by, for example, reading and executing a program stored in a memory circuit or a storage device.

[0073] (Image output unit 40) The image output unit 40 displays various information under the control of the control unit described below. For example, the image output unit 40 outputs a received-light image obtained by the image processing unit 30. The received-light image obtained by the image processing unit 30 includes a received-light image acquired for focus control and a received-light image (photographed image) obtained by projecting the pattern light again after focus control.

[0074] The image output unit 40 includes a display device such as a flat panel display, for example, an LCD (Liquid Crystal Display).

[0075] (Other configurations) In some embodiments, the ophthalmic apparatus 1 further includes a fixation projection system. For example, the optical path of the fixation projection system is coupled to the optical path of the pattern light in the optical system configuration shown in FIG. 1. The fixation projection system can present an internal fixation target or an external fixation target to the subject's eye E. When presenting an internal fixation target to the subject's eye E, the fixation projection system includes an LCD that displays the internal fixation target under control of the control unit, and projects the fixation light beam output from the LCD onto the fundus of the subject's eye E. The LCD is configured to be able to change the display position of the fixation target on its screen. By changing the display position of the fixation target on the LCD, it is possible to change the projection position of the fixation target on the fundus of the subject's eye E. The display position of the fixation target on the LCD can be specified by the user using the operation unit.

[0076] In some embodiments, the fixation projection system includes, instead of an LCD, a panel on which a plurality of LEDs are arranged, for example, and is configured to project a fixation target by lighting any one of the LEDs.

[0077] In addition, since fixation can be induced by changing the projection position of the fixation target on the fundus of the subject's eye E, it also becomes possible to change the observation direction.

[0078] In some embodiments, the ophthalmic apparatus 1 includes an alignment system. In some embodiments, the alignment system includes an XY alignment system and a Z alignment system. The XY alignment system is used to align the device optical system and the subject's eye E in a direction intersecting the optical axis of the device optical system (objective lens). The Z alignment system is used to align the device optical system and the subject's eye E in the direction of the optical axis of the ophthalmic apparatus 1 (objective lens).

[0079] For example, the XY alignment system projects a bright spot in the infrared or near-infrared region onto the subject's eye E. The image processing unit 30 acquires an anterior segment image of the subject's eye E onto which the bright spot is projected, and determines the displacement between the bright spot image depicted in the acquired anterior segment image and the alignment reference position. A control unit (described later) relatively moves the device optical system and the subject's eye E in a direction intersecting with the direction of the optical axis by a moving mechanism (not shown) so that the determined displacement is cancelled.

[0080] For example, the Z alignment system projects alignment light in the infrared or near-infrared region from a position off the optical axis of the device optical system, and receives the alignment light reflected by the anterior segment of the subject's eye E. The image processing unit 30 specifies the distance of the subject's eye E from the device optical system based on the receiving position of the alignment light, which changes depending on the distance of the subject's eye E from the device optical system. A control unit, which will be described later, moves the device optical system and the subject's eye E relatively in the direction of the optical axis using a moving mechanism (not shown) so that the specified distance becomes the desired working distance.

[0081] In some embodiments, the function of the alignment system is realized by two or more anterior eye cameras arranged at a position off the optical axis of the device optical system. For example, as disclosed in JP 2013-248376 A, the image processor 30 analyzes anterior eye images of the subject's eye E acquired substantially simultaneously by two or more anterior eye cameras, and identifies the three-dimensional position of the subject's eye E using a known trigonometric method. The controller described later moves the device optical system and the subject's eye E three-dimensionally relative to each other by a moving mechanism (not shown) so that the optical axis of the device optical system approximately coincides with the axis of the subject's eye E and the distance of the device optical system to the subject's eye E is a predetermined working distance.

[0082] [Control system configuration] The control system of the ophthalmic apparatus 1 will be described with reference to Fig. 3. As shown in Fig. 3, the control system of the ophthalmic apparatus 1 is mainly configured with a control unit 100. Note that at least a part of the configuration of the control system may be included in the ophthalmic apparatus 1.

[0083] (Control unit 100) The control unit 100 controls each unit of the ophthalmic apparatus 1. The control unit 100 includes a main control unit 101 and a storage unit 102. The main control unit 101 includes a processor, and executes control processing of each unit of the ophthalmic apparatus 1 by executing processing according to a program stored in the storage unit 102.

[0084] (Main control unit 101) The main control unit 101 controls the projection system 10 , the light receiving system 20 , the image processing unit 30 , the image output unit 40 , and the focusing mechanism 52 .

[0085] The control of the projection system 10 includes the control of the pattern light generating unit 11. The control of the pattern light generating unit 11 includes the control of the light source 11A and the control of the spatial light modulator 11C. The control of the light source 11A includes switching the light source on and off, and controlling changes in the light amount of the light source. The control of the spatial light modulator 11C includes spatial amplitude control, phase control, and polarization control of the light from the light source 11A, and temporal amplitude control, phase control, and polarization control of the light from the light source 11A.

[0086] When the projection system 10 includes an optical scanner, the main controller 101 can control the optical scanner. Control of the optical scanner includes control of the scan range (scan start position and scan end position) and scan speed.

[0087] The control of the light receiving system 20 includes the control of the image sensor 22. The control of the image sensor 22 includes the change control of at least one of the exposure timing, the sensitivity, and the frame rate, and the readout control by the rolling shutter method or the global shutter method.

[0088] The control of the image processing unit 30 includes control of the execution of the above image processing and control of the execution of the analysis processing. The control of the image output unit 40 includes control of the display of the above various information.

[0089] The control of the focusing mechanism 52 includes control according to the mechanism for focusing the pattern light.

[0090] When the focusing mechanism 52 includes a focusing lens, the main control unit 101 identifies focusing control content corresponding to the amount and direction of movement to which the focal position of the pattern light identified by the image processing unit 30 should be moved, and controls a moving mechanism that moves the focusing lens in the optical axis direction based on the identified focusing control content.

[0091] When the focusing mechanism 52 includes an objective lens, the main control unit 101 identifies focusing control content corresponding to the amount and direction of movement to which the focal position of the pattern light identified by the image processing unit 30 should be moved, and controls a moving mechanism that moves the device body or the objective lens in the optical axis direction based on the identified focusing control content.

[0092] When the focusing mechanism 52 includes a liquid lens or a liquid crystal lens, the main control unit 101 identifies focusing control content corresponding to the amount and direction of movement of the focal position of the pattern light identified by the image processing unit 30, and controls the liquid lens or liquid crystal lens based on the identified focusing control content.

[0093] 3, control information 102A is stored in the storage unit 102. The control information 102A includes correspondence information that associates a plurality of focusing control contents (control amount, types of control signal) for the focusing mechanism 52 with a plurality of combinations of the movement amount and movement direction by which the focal position of the patterned light should be moved. The main control unit 101 can refer to the correspondence information, specify the focusing control contents for the focusing mechanism 52 from the movement amount and movement direction by which the focal position of the patterned light should be moved, which are specified by the image processing unit 30, and control the focusing mechanism 52 based on the specified focusing control contents.

[0094] (Storage unit 102) The storage unit 102 stores various computer programs and data. The computer programs include an arithmetic program and a control program for controlling the ophthalmic apparatus 1. Furthermore, the storage unit 102 stores the control information 102A as described above.

[0095] (Operation unit 110) The operation unit 110 includes an operation device or an input device. The operation unit 110 includes buttons and switches (e.g., an operation handle, an operation knob, etc.) and operation devices (a mouse, a keyboard, etc.) provided on the ophthalmic apparatus 1. The operation unit 110 may also include any operation device or input device, such as a trackball, an operation panel, a switch, a button, or a dial.

[0096] In some embodiments, at least a part of the image output unit 40 and the operation unit 110 are integrally configured. As a specific example, the functions of the image output unit 40 and the operation unit 110 are realized by a touch screen.

[0097] The projection system 10 is an example of a "projection unit" according to the embodiment. The light receiving system 20 and the control unit 100 that controls the image sensor 22 are an example of an "acquisition unit" according to the embodiment. The image processing unit 30 is an example of a "determination unit" according to the embodiment.

[0098] [Operation] Next, the operation of the ophthalmologic apparatus 1 will be described.

[0099] Fig. 4 is an explanatory diagram of the process of identifying the focus state according to the embodiment. Fig. 4 shows the pattern light passing through the focusing lens or the objective lens and its return light, and the received light image RS of the return light superimposed with the projected image PS of the pattern light. In Fig. 4, the projected image PS of the pattern light is typically superimposed on the received light image RS of the return light on the detection surface of the image sensor 22.

[0100] As described above, the projection system 10 can project pattern light of any projection shape onto the subject's eye E. The light receiving system 20 receives the return light of the pattern light at the image sensor 22, and the image processing unit 30 can obtain a received light image corresponding to any aperture shape using, for example, a rolling shutter method based on the detection result of the received return light.

[0101] For ease of explanation, it is assumed that the pattern light PS is projected onto the test eye E from above with respect to the optical axis of the ophthalmic apparatus 1 (objective lens or focusing lens), and the return light RF of the pattern light PS is received from below with respect to the optical axis (Figures 4(A) and (B)). Note that the pattern light PS and the return light RF do not have to be symmetrical with respect to the optical axis. The optical path of either the pattern light PS or the return light RF may be arranged on the optical axis. For example, the optical path of the pattern light PS may be arranged on the optical axis, and the optical path of the return light RF may be arranged above or below the optical axis.

[0102] When the object (e.g., the fundus of the test eye E) is located on the focal plane at the focus position FS, the position of the projected image PS of the pattern light coincides with the position of the aperture on the light receiving side, and a bright received image RS with clear contours is obtained (Figure 4(A)).

[0103] In contrast, when the object is located on the focal plane at a position FS1 away from the focal position FS, the position of the projected image PS of the pattern light and the position of the aperture on the light receiving side are separated, and a dark received image RS with a blurred outline is obtained (Figure 4 (B)).

[0104] Here, the pattern light generating unit 11 moves the projection position of the pattern light on the object further upward or downward. At this time, even if the object is located on the focal plane at position FS1, the position of the projected image PS of the pattern light can be made to coincide with the position of the aperture on the light receiving side. As a result, a bright received light image RS as shown in FIG. 4A is obtained (FIG. 4C).

[0105] That is, the luminance distribution of the received-light image changes by relatively moving the projection position or projection range of the pattern light and the aperture on the light-receiving side in the aperture crossing direction. In this embodiment, the image processor 30 specifies the luminance distribution of the acquired received-light image in the aperture direction, and specifies the focusing state of the pattern light based on the specified luminance distribution.

[0106] 4B and 4C, the projection position (projection range) of the pattern light is moved in a direction perpendicular to the aperture direction, so the brightness of the received light image changes. This makes it possible to determine whether the focal position matches the imaging region, but it is not possible to determine to what extent the focal position does not match the imaging region.

[0107] Therefore, by intersecting the projection position of the pattern light in a direction different from the direction perpendicular to the aperture direction (for example, at 45 degrees), the luminance distribution of the received light image can be changed according to the intersecting direction. This makes it possible to determine whether the focal position coincides with the imaging region, and also to specify the amount and direction of movement of the focal position when it does not coincide.

[0108] In this embodiment, a pattern light is used in which the projection system shape intersects with the aperture direction at approximately 45 degrees as follows: This makes it possible to determine, from a received light image obtained by projecting the pattern light once, whether or not the focal position coincides with the imaging region, and also to specify the amount and direction of movement of the focal position when it does not coincide.

[0109] 5A to 5C are schematic diagrams showing the relationship between the projection shape of the pattern light on the detection surface of the image sensor 22 and the aperture shape on the light receiving side, and the received light image. FIG. 5A mainly shows the projection shape, aperture shape, and received light image when in focus. FIG. 5B shows the projection shape, aperture shape, and received light image when the focal position is on the front side. FIG. 5C shows the projection shape, aperture shape, and received light image when the focal position is on the rear side. In FIGS. 5A to 5C, the projection shape of the pattern light PL intersects with the opening direction of the aperture shape AF at approximately 45 degrees.

[0110] As shown in FIG. 5A, when the light is focused, a received light image Rm with a clear outline is acquired. In the received light image Rm, a bright portion Rp appears in the center of the patterned light PL rather than in the end portion. The bright portion Rp is depicted at a position corresponding to the optical axis (on the detection surface of the image sensor 22). Therefore, the image processing unit 30 can determine the focused state of the patterned light PL (i.e., whether the focal position of the patterned light PL is the position of the imaging site) by analyzing the received light image Rm to specify the position of the bright portion Rp in the luminance distribution in the opening direction and determining whether the position of the specified bright portion Rp is a predetermined reference position (a position corresponding to the optical axis). In some embodiments, the image processing unit 30 can determine the focused state of the patterned light PL by analyzing the received light image Rm to determine whether the bright portion Rp is specified in the luminance distribution in the opening direction. In this case, it is possible to determine whether the bright portion Rp is specified by comparing the luminance level of the bright portion Rp with a predetermined threshold value.

[0111] As shown in FIG. 5B, when the focal position of the pattern light PL is on the front side, a received light image Rm with a blurred outline is acquired. In the received light image Rm, a bright portion Rp1 appears on the end side of the pattern light PL rather than on the center side. For example, the bright portion Rp1 is depicted on the left side of the position corresponding to the optical axis (on the detection surface of the image sensor 22). Therefore, the image processing unit 30 analyzes the received light image Rm to identify the position of the bright portion Rp1 in the luminance distribution in the opening direction, and obtains the displacement (amount of deviation, direction of deviation) of the position of the bright portion Rp1 relative to a predetermined reference position (position corresponding to the optical axis). The image processing unit 30 can, for example, use conversion information representing the amount of movement and direction of movement of the focal position corresponding to the displacement obtained in advance to identify the amount of movement and direction of movement of the focal position corresponding to the displacement. The main control unit 101 identifies focus control information from the amount of movement and direction of movement of the identified focal position, and controls the focusing mechanism 52 based on the identified focus control information.

[0112] As shown in FIG. 5C, when the focal position of the patterned light PL is on the rear side, a received light image Rm with a blurred outline is acquired. In the received light image Rm, a bright portion Rp2 appears on the end side of the patterned light PL rather than on the center side. For example, the bright portion Rp2 is depicted on the right side of the position corresponding to the optical axis (on the detection surface of the image sensor 22). Therefore, the image processing unit 30 analyzes the received light image Rm to identify the position of the bright portion Rp2 in the luminance distribution in the aperture direction, and obtains the displacement of the position of the bright portion Rp2 relative to a predetermined reference position (the position corresponding to the optical axis). The image processing unit 30 can identify the amount of movement and the direction of movement of the focal position corresponding to the displacement of the position of the bright portion Rp2 relative to the reference position, for example, by using conversion information representing the amount of movement and the direction of movement of the focal position corresponding to the displacement obtained in advance. The main control unit 101 identifies focus control information from the amount of movement and the direction of movement of the identified focal position, and controls the focusing mechanism 52 based on the identified focus control information.

[0113] Although a case where a bright area appears when in focus has been described with reference to FIGS. 5A to 5C, the same applies to a case where a dark area appears when in focus.

[0114] As described above, the projection system 10 projects pattern light of a projection shape extending at least in the aperture intersecting direction (first direction) onto the subject's eye E, and the image processing unit 30 acquires a received-light image corresponding to the aperture shape extending at least in the aperture direction (second direction intersecting the first direction) based on the detection result of the return light of the pattern light from the subject's eye E detected by the light receiving system 20. The image processing unit 30 can specify the focusing state of the pattern light based on the luminance distribution of the acquired received-light image. In some embodiments, the focusing state includes information indicating whether or not the image is in focus, and control content for focusing when the image is not in focus.

[0115] Fig. 6 shows a flow diagram of an operation example of the ophthalmologic apparatus 1 according to the embodiment. A computer program for realizing the processing shown in Fig. 6 is stored in the storage unit 102. The main control unit 101 operates according to the computer program to execute the processing shown in Fig. 6.

[0116] Here, it is assumed that the alignment of the optical system of the device with respect to the test eye E is completed by an alignment system not shown, and a fixation target is projected onto the fundus of the test eye E so as to guide it to the desired fixation position by a fixation projection system not shown.

[0117] (S1: Projects pattern light) First, the main control unit 101 controls the pattern light generating unit 11 to generate pattern light having a projection shape for focus control.

[0118] Specifically, the pattern light generating unit 11 generates pattern light extending at least in a direction intersecting the opening direction of the opening shape (aperture intersecting direction). The pattern light generated by the pattern light generating unit 11 passes through the smoothing unit 12, the optical system 13, the optical multiplexer / demultiplexer 50, and the optical system 51, and is projected onto the subject's eye E.

[0119] (S2: Acquire the received light image) Next, the main control unit 101 causes the image processing unit 30 to obtain a received light image.

[0120] Specifically, the pattern light projected onto the subject's eye E by the projection system 10 is reflected by the subject's eye E. The return light of the pattern light from the subject's eye E passes through the optical system 51, the optical multiplexer / demultiplexer 50, and the optical system 21, and forms an image on the detection surface of the image sensor 22. The main control unit 101 reads out the light reception results of the return light by the image sensor 22 using a rolling shutter method corresponding to a predetermined aperture shape. The image processing unit 30 acquires a received light image corresponding to the aperture shape based on the read light reception results.

[0121] (S3:Analysis) Next, the main control unit 101 causes the image processing unit 30 to execute a predetermined analysis process on the received-light image acquired in step S2.

[0122] Specifically, bright and dark areas appear in the acquired received-light image as described above. The image processor 30 specifies the luminance distribution in the aperture direction in the acquired received-light image as described above.

[0123] (S4: Identify the focus state) Next, the main control unit 101 causes the image processing unit 30 to specify the focus state of the pattern light.

[0124] Specifically, as shown in Fig. 5A, the image processor 30 identifies the position of a bright area (or a dark area) from the luminance distribution identified in step S3, and determines whether the position of the identified bright area (or a dark area) is a predetermined reference position (a position corresponding to the optical axis). When it is determined that the position of the identified bright area (or a dark area) is the predetermined reference position, it determines that the focal position of the pattern light is the position of the imaging site.

[0125] When it is determined that the position of the identified bright part (or dark part) is not the predetermined reference position, the image processing unit 30 obtains the displacement of the position of the bright part (or dark part) from the predetermined reference position in the luminance distribution as shown in Fig. 5B or 5C. Furthermore, the image processing unit 30 specifies the movement amount and movement direction of the focal position corresponding to the obtained displacement.

[0126] In some embodiments, the main control unit 101 causes the image output unit 40 to output (display) information corresponding to the specified focus state or the specified amount and direction of movement of the focus position. Information corresponding to the focus state includes information indicating whether the focus position of the patterned light is at the position of the desired imaging site (focus position), information indicating whether the focus position of the patterned light is in front of or behind the focus position, and the like. For example, the main control unit 101 causes the image output unit 40 to display information (or an image, character, mark, or indicator) indicating whether the focus position of the patterned light is at the focus position in green, information indicating that the focus position of the patterned light is in front of the focus position in blue, and information indicating that the focus position of the patterned light is behind the focus position in red. In some embodiments, the main control unit 101 causes the image output unit 40 to display characters, images, and indicators indicating the focus position of the patterned light relative to the focus position.

[0127] (S5: Focus control) Next, the main control unit 101 performs focus control.

[0128] Specifically, when it is determined in step S4 that the focal position of the pattern light is at the position of the region to be photographed, step S5 is skipped.

[0129] On the other hand, when it is determined in step S4 that the focal position of the pattern light is not the position of the part to be photographed, the main control unit 101 identifies focusing control information from the amount of movement and the direction of movement of the focal position identified in step S4, and controls the focusing mechanism 52 based on the identified focusing control information.

[0130] (S6: Shooting) Next, the main control unit 101 controls the pattern light generating unit 11 to generate pattern light in a projection shape for photographing.

[0131] Specifically, the pattern light generating unit 11 generates, for example, a pattern light extending in a direction (for example, the opening direction) approximately parallel to the opening direction of the aperture shape. The pattern light generated by the pattern light generating unit 11 passes through the smoothing unit 12, the optical system 13, the optical multiplexer / demultiplexer 50, and the optical system 51, and is projected onto the subject's eye E. The pattern light projected onto the subject's eye E is reflected by the subject's eye E. The return light of the pattern light from the subject's eye E passes through the optical system 51, the optical multiplexer / demultiplexer 50, and the optical system 21, and is imaged on the detection surface of the image sensor 22. The main control unit 101 reads out the light reception result of the return light by the image sensor 22 by a rolling shutter method corresponding to a predetermined aperture shape. The image processing unit 30 acquires a light reception image corresponding to the aperture shape based on the read light reception result.

[0132] Next, the main controller 101 projects a pattern light of the same projection shape as above onto a projection position shifted in a direction perpendicular to the opening direction, and shifts the opening position in the same manner as above to control the reading of the light reception result of the return light by the image sensor 22. Such control is repeated multiple times to obtain one frame of a received light image, thereby obtaining a fundus image of the subject's eye E.

[0133] This is the end of the operation of the ophthalmologic apparatus 1 (END).

[0134] <Modification> The configuration and control of the ophthalmologic apparatus according to the embodiment are not limited to the above-described aspects. Below, modifications of the embodiment will be described, focusing on the differences from the embodiment.

[0135] (First Modification) In the embodiment, the case where the pattern light generating unit 11 uses a light source and a non-light-emitting device to spatially modulate the light from the light source to generate the pattern light has been described, but the configuration according to the embodiment is not limited to this. In this modification, the pattern light generating unit includes a self-luminous device.

[0136] 7 is a block diagram showing a configuration example of a pattern light generating unit according to a modification of the embodiment. The ophthalmic apparatus according to this modification includes a pattern light generating unit 11a shown in FIG.

[0137] The pattern light generating unit 11a according to this modification includes a self-luminous device 120 and an optical system 121. The self-luminous device 120 realizes a function as a pixelated pattern light generator by generating light modulated for each pixel. Examples of the self-luminous device 120 include a cathode-ray tube (CRT), a plasma display panel (PDP), an organic electro-luminescence (OEL), an LED, an inorganic electro-luminescence (IEL), a vacuum floorescent display (VFD), and a field emission display (FED).

[0138] The self-light-emitting device 120 can be placed at a position that is approximately optically conjugate with a photographing site (e.g., a fundus or an anterior segment) of the subject's eye E. The optical system 121 includes a projection lens for projecting light spatially modulated by the self-light-emitting device 120.

[0139] The operation of the ophthalmologic apparatus according to this modification is similar to that of the embodiment, and therefore a detailed description thereof will be omitted.

[0140] (Second Modification) In the embodiment or its modified example, the projection shape of the pattern light is a straight line (rectangular shape) that intersects with the opening direction, but the configuration according to the embodiment is not limited to this. In this modified example, the projection shape of the pattern light is a curved line. Also, in this modified example, the projection shape of the pattern light is a shape that intersects with the opening direction multiple times.

[0141] Fig. 8 shows a schematic diagram of the projection shape of the pattern light according to the modified example of the embodiment. Fig. 8 shows a schematic diagram of the relationship between the projection shape of the pattern light on the detection surface of the image sensor 22 and the aperture shape on the light receiving side when the pattern light is focused, when the focal position is on the front side, and when the focal position is on the rear side.

[0142] As shown in Fig. 8, when the light is focused, a received-light image with a clear outline is obtained. In the received-light image, the pattern light PL1 intersects the aperture shape AF multiple times, so that bright and dark areas appear alternately. Therefore, the image processing unit 30 can determine the focused state of the pattern light PL1 (i.e., whether the focal position of the pattern light PL1 is the position of the photographed part) by analyzing the received-light image to identify the positions of the bright and dark areas that appear alternately in the luminance distribution in the aperture direction and determining whether any of the identified positions of the multiple bright areas is a predetermined reference position (a position corresponding to the optical axis).

[0143] Furthermore, in this modification, by determining whether or not the positions of a plurality of bright parts are at a predetermined reference position, it becomes possible to determine the focus state of the patterned light PL1 with higher accuracy.

[0144] Similarly, when the focal position of the pattern light PL2 is on the front side or when the focal position of the pattern light PL3 ​​is on the rear side, a received light image with a blurred outline is acquired. In the received light image, the pattern light PL2 and PL3 intersect the aperture shape AF multiple times, so that bright and dark areas appear alternately. Therefore, the image processing unit 30 analyzes the received light image to identify the positions of the bright and dark areas that appear alternately in the luminance distribution in the aperture direction, and obtains the displacement (amount of deviation, direction of deviation) of any of the positions of the multiple bright areas relative to a predetermined reference position (position corresponding to the optical axis). For example, the image processing unit 30 can specify the amount of movement and the direction of movement of the focal position corresponding to the displacement of the position of the bright area relative to the reference position by using predetermined conversion information in the same manner as above. The main control unit 101 specifies focus control information from the amount of movement and the direction of movement of the specified focal position, and controls the focusing mechanism 52 based on the specified focus control information.

[0145] In addition, in this modified example, by calculating the displacement of the positions of multiple bright areas relative to a predetermined reference position and identifying the amount and direction of movement of the focal position corresponding to the multiple displacements thus calculated, it becomes possible to adjust the focal positions of the pattern lights PL2 and PL3 with higher accuracy.

[0146] Although a case where a bright area appears when in focus has been described with reference to FIG. 8, the same applies to a case where a dark area appears when in focus.

[0147] (Third Modification) In the second modified example, the projection shape of the pattern light is described as a shape that intersects with the opening direction multiple times, but the configuration according to the embodiment is not limited to this. For example, the projection shape of the pattern light may be a shape that is highly sensitive to determining the focus state. An example of a shape that is highly sensitive to determining the focus state is a shape that has a part that is approximately parallel to the opening direction at a position corresponding to the optical axis.

[0148] Fig. 9 shows a schematic diagram of a projection shape of a pattern light according to a modified example of the embodiment. Fig. 9 shows a schematic diagram of a relationship between a projection shape of the pattern light on the detection surface of the image sensor 22 and an aperture shape on the light receiving side when the pattern light is focused, when the focal position is on the front side, and when the focal position is on the rear side.

[0149] As shown in Fig. 9, when focusing, a received light image with a clear outline is obtained. Since the pattern light PL11 having a shape having a portion substantially parallel to the opening direction of the aperture shape AF is projected at a position corresponding to the optical axis on the detection surface of the image sensor 22 (a reference position during focusing control), a bright portion appears in the center rather than the end side in the received light image. Therefore, the image processing unit 30 can determine the focused state of the pattern light PL11 (i.e., whether the focal position of the pattern light PL1 is the position of the photographed part) by analyzing the received light image to specify the position of the bright portion in the luminance distribution in the opening direction and determining whether the position of the specified bright portion is a predetermined reference position (a position corresponding to the optical axis).

[0150] Similarly, when the focal position of the pattern light PL12 is on the front side or when the focal position of the pattern light PL13 is on the rear side, a received light image with a blurred outline is acquired. In the received light image, dark areas tend to appear overall. Therefore, the image processing unit 30 analyzes the received light image to identify the position of the bright area in the luminance distribution in the aperture direction, and obtains the displacement (amount of deviation, direction of deviation) of the position of the bright area relative to a predetermined reference position (position corresponding to the optical axis). For example, the image processing unit 30 can identify the amount of movement and the direction of movement of the focal position corresponding to the displacement of the position of the bright area relative to the reference position by using predetermined conversion information in the same manner as above. The main control unit 101 identifies focus control information from the amount of movement and the direction of movement of the identified focus position, and controls the focusing mechanism 52 based on the identified focus control information.

[0151] Although a case where a bright area appears when in focus has been described with reference to FIG. 9, the same applies to a case where a dark area appears when in focus.

[0152] (Fourth Modification) In the embodiment or its modified example, a case where the projection shape of the pattern light intersects with the aperture shape on the light receiving side has been described, but the configuration according to the embodiment is not limited to this. For example, the projection shape of the pattern light may be a shape that extends in a direction substantially parallel to the aperture direction.

[0153] 10A to 10C are schematic diagrams showing the relationship between the projection shape of the pattern light on the detection surface of the image sensor 22 according to a modified embodiment and the aperture shape on the light receiving side. FIG. 10A mainly shows the projection shape and aperture shape when in focus. FIG. 10B shows the projection shape and aperture shape when the focal position is on the front side. FIG. 10C shows the projection shape and aperture shape when the focal position is on the rear side. In FIGS. 10A to 10C, the projection shape of the pattern light PL is assumed to be parallel to the opening direction of the aperture shape AF.

[0154] As shown in Fig. 10A, when the light is focused, a received light image with a clear outline is obtained. The received light image is bright overall. Therefore, the image processing unit 30 can determine the focused state of the patterned light PL (i.e., whether the focal position of the patterned light PL is the position of the photographed part) by analyzing the received light image and determining whether a bright area has been identified in the luminance distribution in the opening direction. In this case, it is possible to determine whether a bright area has been identified by comparing the luminance level of the bright area with a predetermined threshold value.

[0155] 10B or 10C, when the focal position of the patterned light PL is on the front side or the rear side, a received light image with a blurred outline and dark overall is acquired. Therefore, the image processing unit 30 can determine the focusing state of the patterned light PL (i.e., whether the focal position of the patterned light PL is the position of the photographed part or not) by analyzing the received light image and determining whether a bright part is specified in the luminance distribution in the opening direction.

[0156] When no bright area is identified, the main controller 101 relatively moves the projection position of the pattern light and the position of the aperture shape in a direction perpendicular to the aperture direction. Specifically, the main controller 101 controls the pattern light generator 11 (11a) to generate pattern light so that the projection position on the imaging site is shifted. Alternatively, the main controller 101 changes the aperture position by controlling the readout timing of the image sensor 22 receiving the return light of the pattern light, and causes the image processor 30 to obtain a received light image corresponding to the changed aperture position.

[0157] The image processor 30 identifies the luminance level in the luminance distribution of two or more received light images obtained by relatively moving the projection position of the pattern light and the position of the aperture shape, and obtains the difference from a predetermined threshold level. For example, the image processor 30 can identify the amount of movement and the direction of movement of the focal position corresponding to the difference obtained in advance, using conversion information indicating the amount of movement and the direction of movement of the focal position corresponding to the difference. The main controller 101 identifies focusing control information from the identified amount of movement and the direction of movement of the focal position, and controls the focusing mechanism 52 based on the identified focusing control information.

[0158] Although a case where a bright area appears when in focus has been described with reference to FIGS. 10A to 10C, the same applies to a case where a dark area appears when in focus.

[0159] 10A to 10C, the received light image may be acquired using a global shutter method, which eliminates the need to project the pattern light onto the subject's eye multiple times.

[0160] Fig. 11 shows a flow diagram of an operation example of the ophthalmologic apparatus 1 according to the modified embodiment. A computer program for realizing the processing shown in Fig. 11 is stored in the storage unit 102. The main control unit 101 operates according to the computer program to execute the processing shown in Fig. 11.

[0161] Here, it is assumed that the alignment of the optical system of the device with respect to the test eye E is completed by an alignment system not shown, and a fixation target is projected onto the fundus of the test eye E so as to guide it to the desired fixation position by a fixation projection system not shown.

[0162] (S11: Projecting pattern light) First, the main control unit 101 controls the pattern light generating unit 11 to generate pattern light having a projection shape for focus control.

[0163] Specifically, the pattern light generating unit 11 generates a pattern light extending in a direction substantially parallel to the opening direction of the opening shape. The pattern light generated by the pattern light generating unit 11 passes through the smoothing unit 12, the optical system 13, the optical multiplexer / demultiplexer 50, and the optical system 51, and is projected onto the subject's eye E.

[0164] (S12: Acquire the received light image) Next, the main control unit 101 causes the image processing unit 30 to obtain a received-light image, similarly to step S2.

[0165] (S13:Analysis) Next, the main control unit 101 causes the image processing unit 30 to execute a predetermined analysis process on the received-light image acquired in step S12, similarly to step S3.

[0166] (S14: Identify the focus state) Next, the main control unit 101 causes the image processing unit 30 to specify the focus state of the pattern light.

[0167] Specifically, as shown in FIG. 10A, the image processing unit 30 identifies a luminance level from the luminance distribution identified in step S13, and determines whether the received light image is bright by comparing the identified luminance level with a predetermined threshold value.

[0168] (S15:Next?) If it is determined in step S14 that the received light image is bright, it is determined that the focal position of the patterned light is the position of the part to be photographed (S15: N), and the operation of the ophthalmologic apparatus 1 proceeds to step S16.

[0169] When it is determined that the received light image is not bright, it is determined that the focal position of the patterned light is not the position of the photographed part (S15: Y), and the operation of the ophthalmic apparatus 1 proceeds to step S11. In step S11, the main controller 101 controls the patterned light generator 11 (11a) to generate patterned light so that the projection position on the photographed part is shifted. Alternatively, in step S12 following step S11, the main controller 101 changes the aperture position by controlling the readout timing of the reception result of the return light of the patterned light by the image sensor 22, and causes the image processor 30 to obtain the received light image corresponding to the changed aperture position.

[0170] (S16: Focus control) Next, the main control unit 101 performs focus control.

[0171] Specifically, when it is determined in step S14 that the focal position of the pattern light is at the position of the region to be photographed, step S16 is skipped.

[0172] On the other hand, when it is determined in step S14 that the focal position of the pattern light is not the position of the imaging region, the main controller 101 identifies the luminance levels in the luminance distributions of two or more received light images obtained by relatively moving the projection position of the pattern light and the position of the aperture shape, as described above, and obtains the difference from a predetermined threshold level. The image processor 30 identifies the movement amount and movement direction of the focal position corresponding to the obtained difference, for example, using predetermined conversion information. The main controller 101 identifies focusing control information from the identified movement amount and movement direction of the focal position, and controls the focusing mechanism 52 based on the identified focusing control information.

[0173] (S17: Shooting) Next, the main controller 101 controls the pattern light generator 11 to generate pattern light having a projection shape for photographing, as in step S6, and obtains an image of the fundus of the subject's eye E.

[0174] This is the end of the operation of the ophthalmologic apparatus 1 (END).

[0175] In this modified example, in step S11, the projection shape of the pattern light is a shape extending in a direction substantially parallel to the opening direction, but is not limited to this. For example, the projection shape of the pattern light may be a square shape, a circular shape, or a bright spot. That is, by analyzing the image of the test eye E obtained while sequentially changing the projection shape of the pattern light (projection position and projection range on the test eye E) over time, it is possible to specify the focus state of the pattern light (or the amount and direction of movement to be made to the focus position).

[0176] As described above, the projection system 10 projects the pattern light having a projection shape extending at least in the aperture direction onto the subject's eye E, and the image processing unit 30 acquires a received-light image corresponding to the aperture shape extending in a predetermined aperture direction based on the detection result of the return light of the pattern light from the subject's eye E detected by the light receiving system 20. The image processing unit 30 can specify the focusing state of the pattern light based on the luminance distribution of one or more acquired received-light images. In some embodiments, the image processing unit 30 specifies the control content for focusing based on the luminance distribution of two or more received-light images acquired by shifting the projection position of the pattern light or the aperture position.

[0177] [Actions and Effects] The operation and effects of the ophthalmic apparatus and the control method thereof according to the embodiment will be described.

[0178] An ophthalmic apparatus (1) according to some embodiments includes a projection unit (projection system 10), an acquisition unit (a control unit 100 that controls a light receiving system 20 and an image sensor 22), and an identification unit (an image processing unit 30). The projection unit projects pattern light having a projection shape extending at least in a first direction onto the subject's eye (E). The acquisition unit acquires a received-light image corresponding to an aperture shape extending at least in a second direction intersecting the first direction, based on a detection result of return light of the pattern light from the subject's eye. The identification unit identifies the focus state of the pattern light based on the luminance distribution of the received-light image.

[0179] According to this configuration, a received light image corresponding to an opening shape extending at least in a second direction intersecting with the first direction is acquired based on the result of receiving the return light of the pattern light having a projection shape extending at least in a first direction. This makes it possible to acquire a received light image whose luminance distribution changes according to the focusing state of the pattern light. Therefore, it becomes possible to specify the optimal focusing state with good reproducibility with a simple configuration.

[0180] An ophthalmic apparatus (1) according to some embodiments includes a projection unit (projection system 10), an acquisition unit (a control unit 100 that controls a light receiving system 20 and an image sensor 22), and an identification unit (an image processing unit 30). The projection unit projects pattern light having a projection shape extending at least in a first direction onto the subject's eye (E). The acquisition unit acquires a received-light image corresponding to an aperture shape extending at least in the first direction based on a detection result of return light of the pattern light from the subject's eye. The identification unit identifies a focusing state of the pattern light based on a luminance distribution in a second direction intersecting the first direction in one or more received-light images acquired by the acquisition unit.

[0181] According to this configuration, a received light image corresponding to an aperture shape extending at least in the first direction is acquired based on a result of receiving return light of a pattern light having a projection shape extending at least in the first direction, and a focusing state of the pattern light is specified based on a luminance distribution in a second direction intersecting the first direction in one or more acquired received light images. This makes it possible to specify an optimal focusing state with good reproducibility with a simple configuration.

[0182] In some embodiments, the determination unit includes a control unit (110) that determines the focus control content of the pattern light based on the luminance distribution in the second direction in the received light image, and performs focus control of the pattern light based on the determined focus control content.

[0183] According to such a configuration, it is possible to perform focusing control of the pattern light with a simple configuration.

[0184] In some embodiments, the control unit performs focus control so that the bright portion or the dark portion moves to a predetermined position (a position corresponding to the optical axis on the detection surface of the image sensor 22).

[0185] According to such a configuration, since focus control can be performed based on the bright or dark areas appearing in the received light image, it becomes possible to perform focus control of the pattern light with a simple configuration.

[0186] Some embodiments include a focusing mechanism (52) disposed in the optical paths of the pattern light and the return light, and the control unit controls the focusing mechanism based on the specified focusing control content.

[0187] According to such a configuration, it is possible to perform focusing control of the pattern light with a simple configuration.

[0188] In some embodiments, the projection unit includes a projector that outputs a pattern light whose projection shape is changeable.

[0189] According to such a configuration, the projection shape can be easily changed to output pattern light, making it possible to provide an ophthalmic device with a simple configuration that can identify the optimal focus state with good reproducibility.

[0190] In some embodiments, the projection unit outputs pattern light of a first projection shape for identifying a focus state, and after focusing control of the pattern light, outputs pattern light of a second projection shape different from the first projection shape, and the acquisition unit acquires a received light image based on the detection result of the return light of the pattern light of the second projection shape.

[0191] With this configuration, it is possible to provide an ophthalmic device that has a simple configuration and can reproducibly identify the optimal focusing state, perform focusing control of the pattern light, and after focusing control, output a new pattern light to obtain an image of the test eye.

[0192] In some embodiments, the acquisition unit includes an image sensor (22) that detects the returned light, and acquires the received light image by a rolling shutter method.

[0193] According to this configuration, it is possible to provide an ophthalmic apparatus that is capable of identifying an optimal focusing state with good reproducibility using a simple configuration.

[0194] A control method for an ophthalmic device (1) according to some embodiments includes a projection step of projecting pattern light having a projection shape extending at least in a first direction onto a test eye (E), an acquisition step of acquiring a received light image corresponding to an aperture shape extending at least in a second direction intersecting the first direction based on a detection result of return light of the pattern light from the test eye, and an identification step of identifying a focus state of the pattern light based on a luminance distribution of the received light image.

[0195] According to this method, a received light image corresponding to an aperture shape extending at least in a second direction intersecting with the first direction is acquired based on the result of receiving the return light of the pattern light having a projection shape extending at least in a first direction. This makes it possible to acquire a received light image whose luminance distribution changes according to the focusing state of the pattern light. Therefore, it becomes possible to specify the optimal focusing state with good reproducibility with a simple configuration.

[0196] A control method for an ophthalmic device (1) according to some embodiments includes a projection step of projecting pattern light having a projection shape extending at least in a first direction onto a test eye (E), an acquisition step of acquiring a received-light image corresponding to an aperture shape extending at least in the first direction based on a detection result of return light of the pattern light from the test eye, and an identification step of identifying a focus state of the pattern light based on a luminance distribution in a second direction intersecting the first direction in one or more received-light images acquired in the acquisition step.

[0197] According to this method, a received-light image corresponding to an aperture shape extending at least in the first direction is acquired based on a result of receiving return light of a pattern light having a projection shape extending at least in the first direction, and a focusing state of the pattern light is specified based on a luminance distribution in a second direction intersecting the first direction in the acquired one or more received-light images. This makes it possible to specify an optimal focusing state with good reproducibility with a simple configuration.

[0198] In some embodiments, the identifying step includes a control step of identifying a focus control content of the pattern light based on a luminance distribution in the second direction in the received light image, and performing focus control of the pattern light based on the identified focus control content.

[0199] According to this method, it is possible to control the focus of the pattern light with a simple configuration.

[0200] In some embodiments, the projection step includes a first projection step of outputting pattern light of a first projection shape for identifying a focus state, and a second projection step of outputting pattern light of a second projection shape different from the first projection shape after focus control of the pattern light, and the acquisition step includes a first acquisition step of acquiring a received light image corresponding to the opening shape based on a detection result of return light of the pattern light of the first projection shape projected in the first projection step, and a second acquisition step of acquiring a received light image based on a detection result of return light of the pattern light of the second projection shape projected in the second projection step.

[0201] According to this method, with a simple configuration, it is possible to reproducibly identify the optimal focus state and perform focus control of the pattern light, and after focus control, a new pattern light is output to obtain an image of the test eye.

[0202] In some embodiments, the acquiring step acquires the received light image by a rolling shutter method based on the detection result of the return light.

[0203] According to this method, it becomes possible to specify the optimum focusing state with good reproducibility using a simple configuration.

[0204] The above-described embodiment and its modified examples are merely examples for implementing the present invention. Anyone who wishes to implement the present invention may make any modifications, omissions, additions, etc. within the scope of the gist of the present invention.

[0205] In the above embodiment or its modified example, the ophthalmologic apparatus may have any function usable in the field of ophthalmology, such as an axial length measurement function, an intraocular pressure measurement function, a fundus photography function, an optical coherence tomography (OCT) function, and an ultrasonic examination function. The axial length measurement function may be realized by an optical coherence tomograph or the like. The axial length measurement function may be realized by projecting light onto the subject's eye and detecting return light from the fundus while adjusting the position of the optical system in the Z direction (front-back direction) relative to the subject's eye, thereby measuring the axial length of the subject's eye. The intraocular pressure measurement function is realized by a tonometer or the like. The fundus photography function is realized by a fundus camera, a scanning ophthalmoscope (SLO), or the like. The OCT function is realized by an optical coherence tomograph or the like. The ultrasonic examination function is realized by an ultrasonic diagnostic device or the like. The present invention may also be applied to an apparatus (multifunction device) having two or more of these functions.

[0206] In some embodiments, a program for causing a computer to execute the above-mentioned method for controlling an ophthalmologic apparatus is provided. Such a program can be stored in any computer-readable recording medium. As the recording medium, for example, a semiconductor memory, an optical disk, a magneto-optical disk (CD-ROM / DVD-RAM / DVD-ROM / MO, etc.), a magnetic storage medium (hard disk / floppy disk / ZIP, etc.), etc. can be used. In addition, the program can be transmitted and received via a network such as the Internet or a LAN. [Explanation of symbols]

[0207] 1 Ophthalmology equipment 10 Projection system 11, 11a Pattern light generating unit 11A light source 11C Spatial Light Modulator 12 Smoothing section 11B, 13, 21, 51, 121 Optical system 20 Light receiving system 22 Image Sensor 30 Image processing section 40 Image output section 50 Optical multiplexer / demultiplexer 52 Focusing mechanism 100 Control section 101 Main control unit 102 Storage section 102A Control Information 110 Operation section 120 Self-luminous Devices E. Examined eye

Claims

1. An ophthalmologic apparatus that projects a pattern light having a projection shape corresponding to a shape of an opening on a light receiving side onto an eye to be examined, and reads out a reception result of the return light from the image sensor by a rolling shutter method corresponding to the shape of the opening on a detection surface of an image sensor that receives return light of the pattern light from the eye to be examined, a projection unit that projects the pattern light having a projection shape extending in a first direction onto the subject's eye; an acquisition unit that acquires a received light image corresponding to a shape of the opening extending in the first direction based on a detection result of the return light; a determination unit that determines a focus state of the pattern light based on a luminance distribution in a second direction intersecting the first direction in two or more received light images acquired by the acquisition unit; Including, the projection unit projects the pattern light so as to be projected onto a projection position that is moved relatively in the second direction with respect to a position of the opening on the detection surface; an ophthalmic device, wherein the identification unit identifies a luminance level in a luminance distribution of the two or more received light images obtained by moving the projection position relatively to the position of the opening on the detection surface, calculates a difference between the identified luminance level and a predetermined threshold level, and uses predetermined conversion information to identify, as the in-focus state, a movement amount and a movement direction of the focus position corresponding to the calculated difference.

2. the specifying unit specifies a focus control content of the pattern light based on a luminance distribution in the second direction in the received-light image, and a control unit that performs focus control of the pattern light based on the specified focus control content.

2. An ophthalmic apparatus according to claim 1.

3. a focusing mechanism disposed in an optical path of the pattern light and the return light, The control unit controls the focusing mechanism based on the specified focusing control content.

3. An ophthalmic apparatus according to claim 2.

4. The projection unit includes a projector that outputs a pattern light whose projection shape is changeable. The ophthalmic apparatus according to any one of claims 1 to 3.

5. A method for controlling an ophthalmic device, comprising: projecting a pattern light having a projection shape corresponding to a shape of an opening on a light receiving side onto a test eye; and reading out a reception result of the return light from an image sensor by a rolling shutter method in accordance with a shape of the opening on a detection surface of an image sensor that receives return light of the pattern light from the test eye, the method comprising: a projection step of projecting the pattern light having a projection shape extending in a first direction onto the subject's eye; an acquisition step of acquiring a received light image corresponding to a shape of the opening extending in the first direction based on a detection result of the return light; a specifying step of specifying a focusing state of the pattern light based on a luminance distribution in a second direction intersecting the first direction in two or more received light images acquired in the acquiring step; Including, the projection step projects the pattern light so as to be projected onto a projection position that is moved relatively in the second direction with respect to a position of the opening on the detection surface; The identification step includes identifying a luminance level in a luminance distribution of the two or more received light images obtained by moving the projection position relatively to the position of the opening on the detection surface, determining a difference between the identified luminance level and a predetermined threshold level, and using predetermined conversion information, identifying the amount and direction of movement of the focus position corresponding to the determined difference as the focus state.

6. the specifying step specifies a focus control content of the pattern light based on a luminance distribution in the second direction in the received light image, and a control step of performing focus control of the pattern light based on the specified focus control content. The method for controlling an ophthalmic apparatus according to claim 5 .

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