Scanning type ophthalmologic imaging device

Abstract

To reduce noise of a resonant scanner.SOLUTION: A scanning type ophthalmologic imaging device quipped with a scanning part for scanning light from a light source on an imaging object of an eye to be examined, and a light reception element for receiving the return light from the imaging object includes: imaging means for capturing an image on the basis of a reception signal from the light reception element; and control means. The scanning part includes a resonant scanner, which is a first scanner for performing scanning in a longitudinal direction of a visual field and a second scanner, which is a second scanner for performing scanning in a lateral direction of the visual field, whose scanning is slower than that of the resonant scanner. The control part causes the resonant scanner to perform scanning in the longitudinal direction of the visual field so that the visual field in the longitudinal direction by the resonant scanner is narrower than the visual field in the lateral direction by the second scanner, causes the second scanner to perform scanning in the lateral direction of the visual field, and causes the imaging means to acquire an image of the laterally long visual field.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a scanning ophthalmic imaging device equipped with a resonant scanner. [Background technology]

[0002] Conventionally, there has been known a scanning ophthalmic imaging device that uses a resonant scanner as a scanning unit to scan light on an imaging target of an eye to be examined, and obtains an image by receiving the return light from the eye to be examined with a light receiving element (see Patent Document 1). In this type of device, a high-speed scanning resonant scanner is generally used for scanning the eye to be examined in the horizontal direction, and a low-speed scanning galvanometer mirror is used for scanning the eye to be examined in the vertical direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-583 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a resonant scanner performs high-speed scanning, it generates loud noises (for example, resonance noises, friction noises, wind noises, etc.) that may be unpleasant for the examiner and the subject.

[0005] In view of the above-described conventional techniques, an object of the present disclosure is to provide a scanning ophthalmic imaging apparatus capable of reducing noise generated by a resonant scanner. [Means for solving the problem]

[0006] A scanning ophthalmic imaging device provided by a typical embodiment of the present disclosure includes a scanning unit that scans light from a light source over a subject's eye, and a light receiving element that receives return light from the subject, and includes an imaging means that acquires an image based on a light receiving signal from the light receiving element, and a control unit, wherein the scanning unit includes a first scanner that is a resonant scanner that scans the field of view vertically, and a second scanner that scans the field of view horizontally, the second scanner having a slower scanning speed than the resonant scanner, and the control unit controls the resonant scanner to scan the field of view vertically and the second scanner to scan the field of view horizontally so that the vertical field of view of the resonant scanner is narrower than the horizontal field of view of the second scanner, and controls the imaging means to acquire an image of a horizontally long field of view. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic diagram illustrating the configuration of an optical system and a control system of a scanning ophthalmic imaging apparatus according to the present embodiment. [Diagram 2] 1 is a diagram showing the scanning of light in a field of view on an object to be photographed in a conventional scanning ophthalmic imaging device; [Diagram 3] 1 is a diagram showing the scanning of light in a field of view on an object to be imaged in a scanning ophthalmic imaging device of the present disclosure; [Figure 4] FIG. 1 is a diagram showing so-called equal loudness curves. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [overview] Hereinafter, one exemplary embodiment will be described with reference to the drawings. Note that the items grouped in <> below can be used independently or in conjunction with each other.

[0009] For example, a scanning ophthalmic imaging device (e.g., scanning ophthalmic imaging device 1) includes an imaging means (e.g., an imaging optical system 2, a control unit 50) having a scanning unit (e.g., an operation unit 16), and a control unit (e.g., the control unit 50).

[0010] <Method of filming> For example, the photographing means includes a photographing optical system (for example, the photographing optical system 2). For example, the photographing optical system includes a light projecting optical system (for example, the light projecting optical system 10) and a light receiving optical system (for example, the light receiving optical system 20). For example, the light projecting optical system includes a scanning unit (for example, the scanning unit 16) that scans the light from the light source on the photographing target of the subject's eye. For example, it includes a light receiving element (for example, the light receiving element 25) that receives return light from the photographing target. For example, the photographing means includes a control unit (for example, the control unit 50) that processes the light receiving signal output from the light receiving element. The control unit acquires a photographed image based on the light receiving signal from the light receiving element.

[0011] <Scanning section> For example, the scanning unit includes a first scanner (for example, a resonant scanner 17) and a second scanner (for example, a galvano scanner 18). For example, the first scanner is a resonant scanner, and the second scanner is a scanner with a slower scanning speed than the resonant scanner. For example, the second scanner scans light in a direction intersecting the scanning direction of the first scanner. For example, the resonant scanner performs main scanning of light. For example, the second scanner performs sub-scanning of light. For example, the resonant scanner is used to perform vertical scanning of the field of view. For example, the second scanner is used to perform horizontal scanning of the field of view.

[0012] For example, the resonant scanner is a resonant type optical scanner. For example, the resonant scanner includes a mirror (for example, mirror 17A) that reflects light. For example, the resonant scanner includes a drive unit (for example, drive unit 17B) that rotates the mirror so that it reciprocates. For example, the resonant scanner resonates the mirror at high speed at a set resonant frequency. For example, the second scanner may be a galvano scanner.

[0013] <Control Unit> For example, the control unit controls the driving of the resonant scanner and the second scanner, and makes the resonant scanner perform vertical scanning of the field of view and the second scanner perform horizontal scanning of the field of view so that the vertical field of view of the resonant scanner is narrower than the horizontal field of view of the second scanner, thereby causing the imaging means to acquire an image of a horizontally elongated field of view. This makes it possible to suppress the noise of the resonant scanner. In other words, for the same horizontally elongated field of view, scanning the vertical direction with the resonant scanner can reduce the amplitude of the scan of the resonant scanner and increase the frequency, thereby making it possible to suppress the noise of the resonant scanner from the characteristics indicated by the equal loudness curves.

[0014] In addition, the vertical field of view of the captured image is easily obscured by the eyelids and eyelashes of the subject's eye, so the actual field of view is not very narrow. In addition, in this disclosure, the "field of view" is defined as the range of the subject used to acquire and generate the captured image. The field of view is determined by the angle of view. In other words, the field of view is determined by the deflection angle of the mirror of the scanning unit and the shooting magnification of the shooting optical system.

[0015] For example, a resonant scanner having a resonance frequency set in the range of 4 kHz or more and 10 kHz or less may be used. If the resonance frequency is within this range and the resonant scanner is caused to perform vertical scanning of the field of view so that the vertical field of view is narrower than the horizontal field of view, noise can be suppressed compared to the conventional method. In other words, a resonant scanner having a resonance frequency in the range of 4 kHz or more and 10 kHz or less and determined based on the number of pixels of the captured image acquired by the imaging means and the acquisition time of one image may be used. Then, the control unit may cause the resonant scanner to perform vertical scanning based on the amplitude of the resonant scanner set based on the vertical size of the horizontal field of view. This allows noise to be suppressed compared to the case where the resonant scanner is used to scan the horizontal field of view.

[0016] For example, the resonant frequency of the resonant scanner is preferably set in the range of 4 kHz or higher and 8 kHz or lower. The control unit may cause the resonant scanner with the resonant frequency set in this range to perform vertical scanning. This also makes it possible to suppress noise compared to the conventional technique.

[0017] For example, when obtaining a photographed image with a horizontally long field of view, the control unit may switch the vertical and horizontal scanning directions of the resonant scanner and the second scanner, and perform horizontal scanning with the resonant scanner and vertical scanning with the second scanner, and perform vertical scanning with a resonant scanner with a resonance frequency determined under the condition that the distance on the photographed object per pixel of the photographed image and the time required to acquire one pixel are maintained (in other words, the total number of pixels of the photographed image and the time required to acquire one photographed image are maintained). Note that the amplitude of the resonant scanner is determined by determining the vertical size of the horizontally long field of view. As a result, a photographed image can be obtained under the same conditions as when the resonant scanner scans horizontally, except that the vertical field of view is narrowed, while suppressing the noise of the resonant scanner. Note that the resonance frequency of the resonant scanner may be preset under the above conditions.

[0018] Also, for example, when the scanning ophthalmic imaging apparatus is provided with a changer (e.g., monitor 52, operation unit 54) for changing the vertical size of the field of view, the control unit may determine the amplitude of the resonant scanner according to the change in the vertical size of the field of view, and control the driving of the resonant scanner based on the determined amplitude to cause the resonant scanner to perform vertical scanning. This changes the noise level of the resonant scanner, but allows a photographed image with a vertical size as required to be obtained. For example, when the subject's eye can open the eyelids widely and it is desired to obtain a photographed image with a large vertical size of the field of view (e.g., an image with an aspect ratio of 1:1 as in the conventional case), this can be accommodated. Conversely, when it is acceptable for the vertical size of the photographed image to be small, the noise can be reduced. The changer may change the vertical size without changing the horizontal size of the field of view.

[0019] [Example] An embodiment of the present disclosure will be described below with reference to the drawings. FIG. 1 is a schematic diagram of an optical system and a control system of a scanning ophthalmic imaging device 1 of this embodiment. The scanning ophthalmic imaging device 1 of this embodiment is a scanning laser ophthalmoscope (SLO) that captures a front image of the fundus of a subject's eye as an imaging target. However, the scanning ophthalmic imaging device 1 may be a device other than a scanning laser ophthalmoscope (e.g., an optical coherence tomography (OCT)). The scanning ophthalmic imaging device 1 may also be a device integrated with other devices such as an OCT or a perimeter.

[0020] <Photographic optical system> The scanning ophthalmic imaging device 1 includes an imaging optical system 2 constituting an imaging means. The imaging optical system 2 includes a light projecting optical system 10 and a light receiving optical system 20. The light projecting optical system 10 projects illumination light onto the fundus of the subject's eye. The light projecting optical system 10 includes a light source 11, a condenser lens 12, a perforated mirror 13, a lens 14, a lens 15, a scanning unit 16, and an objective lens system 19.

[0021] A laser diode (LD), a superluminescent diode (SLD), an LED, or the like may be used as the light source 11. Light emitted from the light source 11 (illumination light in this embodiment) passes through a condenser lens 12, an opening 13A formed in a perforated mirror 13, and passes through lenses 14 and 15 toward a scanning unit 16. The light that has passed through the scanning unit 16 passes through an objective lens system 19 and is then projected onto the fundus of the subject's eye. As a result, the light reflected and scattered by the fundus is emitted from the pupil.

[0022] In this embodiment, the lens 14 is provided so as to be movable in the direction of the optical axis L1 by a driving mechanism 14A. The diopters of the light projecting optical system 10 and the light receiving optical system 20 change depending on the position of the lens 14. In this embodiment, the diopter error of the subject's eye is corrected (reduced) by adjusting the position of the lens 14. As a result, the focusing position of the light is adjusted to the observation site of the fundus (for example, the retinal surface).

[0023] The scanning unit 16 changes the traveling direction (deflection direction) of the light guided from the light source 11 to scan the light on the subject. The scanning unit 16 includes a resonant scanner 17 as a first scanner and a galvano scanner 18 as a second scanner. In this embodiment, the resonant scanner 17 performs main scanning of the light in the vertical direction (Y direction). The galvano scanner 18 performs sub-scanning of the light in the horizontal direction (X direction).

[0024] The resonant scanner 17 scans the light reciprocally on the subject for each scanning line. The resonant scanner 17 includes a mirror 17A that reflects the light, and a drive unit 17B that rotates the mirror 17A so that the mirror 17A reciprocates. The resonant scanner 17 is a resonant type optical scanner that resonates the mirror 17A at high speed at a preset resonant frequency. As a result, the light is scanned reciprocally on the subject in a line shape. The details of the scanning by the resonant scanner 17 will be described later.

[0025] The galvano scanner 18 scans light in a direction intersecting (orthogonal to) the scanning direction of the resonant scanner 17. The galvano scanner 18 includes a mirror 18A that reflects light, and a drive unit 18B that rotates the mirror 18A so that it reciprocates. The mirror 18A of the galvano scanner 18 reciprocates once while the mirror 17A of the resonant scanner 17 reciprocates multiple times. That is, the second scanner, for example the galvano scanner 18, scans at a slower speed than the resonant scanner 17. For example, a sawtooth wave for reciprocating the galvano scanner 18 may be output once while the resonance signal of the resonant scanner 17 is output for multiple periods. In consideration of the stability of the operation, it is preferable that the secondary scanning of light is controlled by a uniform linear motion.

[0026] The scanning ophthalmic imaging device 1 of this embodiment scans light in two-dimensional directions by combining a resonant scanner 17 and a galvano scanner 18. The contact angle of the resonant scanner 17 and the galvano scanner 18 is determined by the relationship between the field of view of the captured image and the imaging magnification of the imaging optical system 2.

[0027] The objective lens system 19 forms a rotation point P around which the light passing through the scanning unit 16 is rotated. The rotation point P is formed on the optical axis L3 of the objective lens system 19, at a position optically conjugate with the scanning unit 16 with respect to the objective lens system 19. The light passing through the scanning unit 16 is irradiated onto the fundus through the rotation point P by passing through the objective lens system 19. Therefore, the light passing through the objective lens system 19 is rotated around the rotation point P as a center with the operation of the scanning unit 16. The light irradiated onto the fundus, which is the subject of the image, is reflected at a focusing position (for example, the retinal surface). The reflected light reflected by the subject of the image is emitted from the pupil as parallel light. Note that, although the objective lens system 19 is illustrated as a single objective lens in FIG. 1, the objective lens system 19 may be composed of a plurality of lenses. Also, at least one of a cemented lens and an aspherical lens may be used for the objective lens system 19.

[0028] The light receiving optical system 20 shares each of the components arranged between the objective lens system 19 and the perforated mirror 13 of the light projecting optical system 10. The light receiving optical system 20 includes a lens 21, a pinhole plate 23, a lens 24, and a light receiving element 25. The light receiving element 25 receives the light projected by the light projecting optical system 10 and reflected by the subject, and outputs a light receiving signal. For example, an APD (avalanche photodiode) having sensitivity in the infrared range may be used as the light receiving element 25. The pinhole plate 23 is arranged at a position conjugate with the fundus, and functions as a confocal aperture.

[0029] The return light from the subject's eye (in this embodiment, the reflected light reflected by the fundus) is taken out of the pupil, and then travels in the opposite direction through the light projection optical system 10 toward the perforated mirror 13. The reflected light from the subject is reflected by the perforated mirror 13 and directed to the optical path L2 in which the light receiving element 25 is disposed, passes through the lens 21, and is focused on the opening of the pinhole plate 23. The light that has passed through the opening of the pinhole plate 23 is received by the light receiving element 25 via the lens 24. For example, every time the scanning unit 16 scans one frame of light, the light receiving signal for one frame output from the light receiving element 25 is processed by the control unit 50. As a result, one frame of a captured image is generated.

[0030] <Control system> 1, the scanning ophthalmic imaging apparatus 1 includes a control unit 50, a monitor 52, an operation unit 54, and a memory 56 which is an example of a storage unit. The control unit 50 includes a CPU (processor), a RAM, a ROM, etc., and is responsible for overall control of the scanning ophthalmic imaging apparatus 1. The control unit 50 is connected to electrical elements of the imaging optical system 2, such as the light source 11, the driving mechanism 14A, the driving unit 17B and driving unit 18B of the scanning unit 110, and the light receiving element 25, and controls the driving of these elements. The control unit 50 also processes a light receiving signal output from the light receiving element 25, and obtains a photographed image based on the light receiving signal. The control unit 50 may also function as a processing unit for processing the obtained photographed image.

[0031] The monitor 52 displays the captured image acquired by the photographing optical system 2, etc. The operation unit 54 is used by the examiner to input various signals. For example, the operation unit 54 may be configured with a keyboard, a mouse, a switch unit on which various operation switches are arranged, etc. In addition, by providing the monitor 52 with a touch panel function, the touch panel may also serve as the operation unit 54. The control unit 50 also functions as a receiving means for receiving various operation signals input by the operation unit 54. In the memory 56, various images acquired by the photographing optical system 2 are stored. In addition, in the memory 56, various control programs are stored.

[0032] <Light scanning by the scanning unit> Next, the relationship between the optical scanning by the scanning unit 16 and the noise of the resonant scanner 17 will be described.

[0033] Fig. 2 is a diagram showing the scanning of light in a field of view VF1 on a subject (field of view in this embodiment means a range used for acquiring and generating a photographed image) in a conventional scanning ophthalmic imaging device. Note that the conventional device also has the same optical system as shown in Fig. 1, and is equipped with a resonant scanner 17 and a galvano scanner 18 of a scanning unit 16.

[0034] In the conventional device, the resonant scanner 17 scans light in the horizontal direction (X direction) of the field of view VF1, and the galvano scanner 18 scans light in the vertical direction (Y direction) of the field of view VF1. The aspect ratio (vertical size and horizontal size) of the field of view VF1 is the same (including the case where they are approximately the same).

[0035] 3 is a diagram showing the scanning of light in a field of view on a subject in the scanning ophthalmic imaging device 1 of the present disclosure. In this embodiment, the field of view on the subject is a horizontally long field of view VF2 in which the vertical size is narrower than the horizontal size. In other words, the vertical and horizontal sizes of the field of view are the vertical and horizontal angles of view, respectively. The angle of view is determined by the contact angle of the resonant scanner 17 (mirror 17A) and the galvano scanner 18 (mirror 18A) and the imaging magnification.

[0036] Here, the horizontal width of the visual field VF2 is θx, and the vertical width is θy. In addition, when scanning in the horizontal direction (X direction) with the resonant scanner 17 and scanning in the vertical direction (Y direction) with the galvano scanner 18 as in the conventional device, the amplitude of the resonant scanner 17 is Aa, and the resonant frequency is Fa.

[0037] In the embodiment of the present disclosure, the scanning directions of the resonant scanner 17 and the galvano scanner 18 are interchanged with respect to the conventional device. That is, the resonant scanner 17 performs light scanning in the vertical direction (Y direction) of the field of view VF2, and the galvano scanner 18 performs light scanning in the horizontal direction (X direction) of the field of view VF1. If the distance on the subject per pixel of the captured image obtained by the imaging optical system 2 and the time required to acquire one pixel are maintained (in other words, under the condition that the total number of pixels of the captured image and the time required to acquire one captured image are maintained), the amplitude Ab of the mirror 17A of the resonant scanner 17 and its resonance frequency Fb are expressed by the following formulas.

[0038] Ab=(θy / θx)×Aa (Formula 1) Fb=(θx / θy)×Fa (Formula 2)

[0039] Therefore, when the scanning direction of the resonant scanner 17 is changed from the horizontal direction to the vertical direction, the following formula is obtained.

[0040] Aa×Fa=Ab×Fb=constant (Formula 3)

[0041] Next, the intensity of the sound is proportional to the square of the amplitude of the air pressure and the square of the frequency. In addition, the amplitude of the air pressure is proportional to the amplitude A of the mirror 17A of the resonant scanner 17, and the frequency of the air pressure is equal to the resonance frequency F of the mirror 17A of the resonant scanner 17. Therefore, if the proportional multiplier is omitted, the intensity of the sound is expressed by the following formula 4.

[0042]

number

[0043] On the other hand, the loudness of noise perceived by humans is evaluated not by the intensity of the sound but by its "loudness." Figure 4 shows so-called equal loudness curves (maps of frequency and sound intensity that humans perceive as equal loudness, connected as contour lines), and in this diagram, the equal loudness curves ELC of the loudness of sounds perceived by humans are plotted with frequency on the horizontal axis and sound intensity on the vertical axis.

[0044] For example, if the resonant frequency of the conventional resonant scanner 17 that scans light in the horizontal direction is 4 kHz, when focusing on the resonant frequency of 4 kHz in FIG. 4, the equal loudness curve ELC generally shows an upward trend in the range of 4 kHz to 8 kHz. Therefore, it can be seen that in this range, even if the sound intensity is the same, the loudness of the sound (i.e., noise) is perceived as smaller as the frequency is higher. Note that even in the frequency range of 8 to 10 kHz, the equal loudness curve ELC is located higher than in the case of a frequency of 4 kHz in horizontal scanning.

[0045] Therefore, by configuring the resonant scanner 17 to perform scanning in the vertical direction and the galvano scanner 18 to perform scanning in the horizontal direction with a horizontally elongated field of view narrower than the vertical direction, the amplitude of the resonant scanner 17 (mirror 17A) can be reduced compared to the case where the resonant scanner 17 performs scanning in the horizontal direction (under the same horizontal size condition), and therefore the resonance frequency can be increased. For example, if the horizontally elongated field of view has a horizontal to vertical ratio of 4:3, the amplitude of the vertical scan of the resonant scanner 17 can be reduced to 3 / 4 compared to the horizontal scan, and therefore the resonance frequency can be increased by 4 / 3 times. As a result, the noise generated by the drive of the resonant scanner 17 can be reduced compared to the case where the resonant scanner 17 performs scanning in the horizontal direction. The resonance frequency of the resonant scanner 17 in this case may be determined based on the number of captured images to be acquired and the acquisition time of one image, within a range of 4 kHz to 10 kHz. The amplitude of the resonant scanner 17 is determined based on the vertical size of the horizontally elongated field of view.

[0046] In addition, when photographing the ocular tissues of a subject's eye (e.g., the fundus), the vertical (up and down) field of view is easily obscured by the eyelids and eyelashes, so even if the vertical field of view is narrowed to make it longer, the actual field of view does not change significantly.

[0047] <Shooting action> The scanning ophthalmologic imaging device 1 having the above configuration is used, for example, for fundus imaging. When photographing the fundus, the imaging optical system 2 is aligned with the subject's eye, and the lens 14 is moved by the driving mechanism 14A according to the diopter of the subject's eye, so that the focal position for imaging is focused on the observation site of the fundus.

[0048] In addition, when photographing the fundus, the control unit 50 controls the driving of the driving unit 17B of the resonant scanner 17 and the driving unit 18B of the galvano scanner 18, so that the resonant scanner 17 performs vertical light scanning and the galvano scanner 18 performs horizontal light scanning. At this time, the control unit 50 controls the driving of the driving units 17B and 18B so that a photographed image of a horizontally elongated field of view is acquired. In this control, the amplitude of the resonant scanner 17 is set according to the vertical size (in other words, the vertical angle of view) of the horizontally elongated field of view (photographed image) that is set in advance. The control unit 50 controls the driving of the resonant scanner 17 (the driving unit 17B of the mirror 17A) based on the set amplitude, so that the resonant scanner 17 performs vertical scanning of the field of view. This makes it possible to reduce noise generated by driving the resonant scanner 17. Then, the control unit 50 generates and acquires a photographed image based on a light receiving signal from the light receiving element 25. The captured image acquired by the control unit 50 is displayed on the monitor 52 .

[0049] <Example of transformation> Although typical embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments shown here, and various modifications are possible.

[0050] For example, in the above description, the vertical and horizontal sizes of the field of view (photographed image) and the amplitude of the resonant scanner 17 are pre-determined, but this is not limiting. For example, a change means for changing the vertical size without changing the horizontal size of the field of view may be provided, and the amplitude of the resonant scanner may be changed based on the change in the vertical size. In this case, for example, the change means for the vertical size of the field of view may be configured to change the value of the vertical size of the field of view displayed on the monitor 52 by an instruction signal from the operation unit 54. Then, when the vertical size is changed, the control unit 50 determines the amplitude of the resonant scanner 17 according to the change in the vertical size, and controls the driving of the resonant scanner 17 based on the determined amplitude. This changes the noise level of the resonant scanner 17, but allows a photographed image having a vertical size appropriate to the need to be obtained. For example, when the subject's eye can open the eyelids widely and a photographed image with a wide vertical size of the field of view (for example, an image with an aspect ratio of 1:1 as in the conventional art) is desired to be obtained, this can be accommodated. Conversely, when the vertical size of the photographed image may be small, the noise can be reduced.

[0051] When the amplitude of the resonant scanner 17 is changed and the captured image is distorted in the vertical direction, the distortion may be corrected by the image processing means (control unit 50).

[0052] Also, for example, the light source 11 of the light projection optical system 10 may emit light of three colors in the visible range, blue, green, and red, so as to obtain a color photographed image. When obtaining a color photographed image, the light receiving element 25 may be composed of three light receiving elements that receive one each of the three colors of blue, green, and red. [Explanation of symbols]

[0053] 1. Scanning ophthalmic imaging device 2. Shooting Optical System 10. Projection optical system 16 Scanning section 17 Resonant Scanner 17A Mirror 17B Drive unit 18 Galvanometer Scanner 20 Light receiving optical system 25 Photodetector 50 Control section

Claims

1. An imaging means including a scanning unit that scans a light from a light source on an object to be imaged of the subject's eye, and a light receiving element that receives return light from the object to be imaged, and that obtains an image based on a light receiving signal from the light receiving element; A control unit, The scanning unit includes a first scanner, which is a resonant scanner, for scanning a field of view in a vertical direction, and a second scanner, which is a second scanner for scanning a field of view in a horizontal direction, and has a scanning speed slower than that of the resonant scanner; The control unit causes the resonant scanner to scan the field of view vertically so that the vertical field of view of the resonant scanner is narrower than the horizontal field of view of the second scanner, causes the second scanner to scan the field of view horizontally, and causes the imaging means to acquire an image of a horizontally elongated field of view.

2. 2. The scanning ophthalmologic imaging apparatus of claim 1, The resonant frequency of the resonant scanner is set to a range of 4 kHz to 10 kHz, The control unit controls the resonant scanner to perform vertical scanning based on an amplitude determined on the basis of a vertical size of the horizontally elongated field of view.

3. 3. The scanning ophthalmologic imaging apparatus according to claim 1, A change means for changing a vertical size without changing a horizontal size of the field of view is provided, The control unit determines an amplitude of the resonant scanner in response to a change in the vertical size of the field of view, and controls driving of the resonant scanner based on the determined amplitude.

Images