JP2012213555A - Fundus photographing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fundus photographing apparatus capable of respectively drawing the various regions of the fundud oculi in proper exposure.SOLUTION: The fundus photographing apparatus includes an illumination optical system 100, a photographing optical system 120, a control part 210 and an HDR processing part 241. The illumination optical system 100 irradiates the fundus Ef of an eye E to be examined with photographing illumination light and the photographing optical system 120 contains a photographing element 9a and guides the fundus reflected light of the photographing illumination light to the photographing element 9a. The control part 210 controls the illumination optical system 100 and the photographing optical system 120 to perform the photographing of the fundus Ef, a plurality of times while altering exposure. The HDR processing part 241 applies high dynamic range synthesis to a plurality of images different in exposure obtained by the plurality of times of the photographing to form a fundus image.

Description

  The present invention relates to a fundus imaging apparatus.

  An apparatus for photographing the fundus for observing the state of the eye to be examined is known (see, for example, Patent Document 1). The fundus imaging apparatus illuminates the fundus with flash light and detects the fundus reflection light with a CCD (Charge Coupled Device) image sensor or the like, thereby generating a fundus image composed of digital data.

JP 2006-247076 A

  Generally, the fundus image has uneven brightness. For example, the optic disc is drawn brightly and the macula is drawn darkly. Therefore, if the exposure is applied to the brightly drawn part, the darkly drawn part is underexposed (that is, the black part is crushed), and conversely, if the exposure is applied to the darkly drawn part, The part to be drawn is underexposed (that is, whiteout).

  As described above, in the conventional technique, it is impossible to draw various portions of the fundus with appropriate exposure. Therefore, various parts of the fundus cannot be observed in detail. In addition, since the degree of reflection of illumination light on the fundus varies among individuals, exposure adjustment is difficult and cumbersome.

  In addition, with the conventional technology, it has been difficult to obtain an image in which various depths of the fundus are in focus. For example, it has been difficult to obtain an image in which all depth parts of the optic nerve head (that is, from the opening to the bottom) are in focus.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a fundus imaging apparatus capable of drawing various portions of the fundus with appropriate exposure.

  Another object of the present invention is to provide a fundus imaging apparatus capable of obtaining a fundus image in focus at various depths.

In order to achieve the above object, a fundus imaging apparatus according to a first aspect includes an illumination optical system, an imaging optical system, a control unit, and an image generation unit. The illumination optical system irradiates illumination light to the fundus of the eye to be examined. The imaging optical system includes an image sensor and guides fundus reflection light of illumination light to the image sensor. The control unit controls the illumination optical system and the photographing optical system so that the fundus is photographed a plurality of times while changing the exposure. The image generation unit generates a fundus image by performing high dynamic range synthesis on a plurality of images with different exposures obtained by a plurality of shootings.
The invention according to claim 2 is the fundus photographing apparatus according to claim 1, wherein the photographing optical system includes a focusing lens for changing a focal position. Furthermore, the control unit changes the focal position with respect to the fundus by controlling the focusing lens as well as changing the exposure in the plurality of times of photographing.
The invention according to claim 3 is the fundus imaging apparatus according to claim 2, wherein the control unit changes the focal position at least in the range of the depth of the optic nerve head. Further, the control unit changes the exposure at least in a range corresponding to the luminance range in the image of the optic disc.
The invention according to claim 4 is the fundus imaging apparatus according to any one of claims 1 to 3, wherein the control unit is one or more of the following controls: (1) Change of illumination light intensity; (2) Change of illumination light irradiation time; (3) Change of detection time of fundus reflected light by image pickup device; (4) Image pickup device Change of shooting sensitivity.
The invention described in claim 5 includes an illumination optical system, a photographing optical system, a control unit, and an image generation unit. The illumination optical system irradiates illumination light to the fundus of the eye to be examined. The photographing optical system includes a focusing lens for changing the focal position, and guides fundus reflection light of illumination light to the image sensor. The control unit controls the illumination optical system and the photographing optical system to perform photographing of the fundus a plurality of times while changing the focal position with respect to the fundus. The image generation unit generates a fundus image by combining a plurality of images having different focal positions obtained by a plurality of shootings.

  According to the first aspect of the present invention, a plurality of images with different exposures are acquired by photographing the fundus a plurality of times while changing the exposure, and a fundus image is obtained by performing high dynamic range composition on the plurality of images. Generate. Therefore, it is possible to draw various portions of the fundus with appropriate exposure.

  In the second aspect of the present invention, a plurality of images having different focal positions are acquired by photographing the fundus a plurality of times while changing the focal position, and a fundus image is generated by combining the plurality of images. Therefore, it is possible to obtain a fundus image in which various parts of the fundus are in focus.

It is the schematic showing an example of the whole structure of embodiment of the fundus imaging apparatus concerning this invention. It is the schematic showing an example of a structure of the optical system of embodiment of the fundus imaging apparatus concerning this invention. It is a schematic block diagram showing an example of the structure of the control system of embodiment of the fundus imaging apparatus concerning this invention.

  An example of an embodiment of a fundus imaging apparatus according to the present invention will be described. In this embodiment, a fundus camera will be described. However, for example, a slit lamp (slit lamp microscope apparatus) or an ophthalmic surgical microscope may be used.

[overall structure]
FIG. 1 shows the overall configuration of the fundus imaging apparatus according to this embodiment. This fundus imaging apparatus includes a fundus camera body 1 and a computer 200.

  The fundus camera main body 1 is equipped with an optical system and a control system for photographing the fundus of the eye E, and various user interfaces for operating the fundus photographing apparatus, as in the past. The computer 200 executes various control processes and image processes.

  A gantry 3 is provided on the base 2 of the fundus camera body 1. The gantry 3 is configured to be movable three-dimensionally on the base 2. A control panel 3 a and a joystick 4 are installed on the gantry 3. The operator moves the gantry 3 three-dimensionally on the base 2 by operating the joystick 4. An operation button 4a provided on the top of the joystick 4 is a trigger button for photographing the fundus.

  A support column 5 is erected on the base 2. The column 5 is provided with a chin rest 6a, a forehead pad 6b, and an external fixation lamp 7. The subject's chin is placed on the chin rest 6a. The forehead of the subject is brought into contact with the forehead pad 6b. The external fixation lamp 7 emits light for fixing the eye E to be examined.

  A main body 8 is mounted on the gantry 3. The main body 8 stores various optical systems and control systems of the fundus camera main body 1. The control system may be provided inside the base 2 or the gantry 3 or may be provided in the computer 200. The control system may be distributed in both the fundus camera body 1 and the computer 200.

  An objective lens unit 8 a is provided on the eye E side of the main body unit 8. The objective lens unit 8a is disposed at a position facing the eye E by alignment before examination. Further, the main body portion 8 is provided with an eyepiece lens portion 8b for the examiner to observe the eye E with the naked eye.

  Furthermore, the main body 8 is provided with two imaging devices 9 and 10 for photographing the eye E to be examined. Each imaging device 9, 10 is detachable from the main body 8.

  The imaging devices 9 and 10 are digital cameras equipped with imaging elements 9a and 10a, respectively (see FIG. 2). Each of the imaging elements 9a and 10a includes a CCD image sensor, a CMOS (Complementary Metal Oxide Semiconductor) image sensor, and the like.

  The image sensors 9a and 10a receive light in different wavelength regions, for example. In this embodiment, the image sensor 9a receives light in the visible region, and the image sensor 10a receives light in the visible region and the infrared region. The image sensor 9a is used for color photography, for example. The image sensor 10a is used, for example, for monochrome photography (moving image observation, fluorescence photography, etc.). The imaging devices 9 and 10 are provided with control circuits that change the imaging conditions of the imaging elements 9a and 10a, respectively. Imaging conditions include imaging sensitivity (gain), detection time (accumulation time), number of imaging pixels, and the like.

  In this embodiment, two imaging devices are used. However, in the present invention, it is sufficient that at least one imaging device is provided. The fundus camera may be a mydriatic type or a non-mydriatic type.

[Configuration of optical system]
The configuration of the optical system of the fundus camera body 1 will be described with reference to FIG. The optical system of the fundus camera body 1 includes an illumination optical system 100 and a photographing optical system 120. The illumination optical system 100 irradiates the fundus oculi Ef with illumination light. The photographing optical system 120 guides the fundus reflection light of the illumination light to the eyepiece unit 8 b and the imaging devices 9 and 10.

  Although not shown, an alignment optical system and a split optical system are provided in addition to these optical systems. The alignment optical system projects a target (alignment target) for performing alignment (positioning) of the imaging optical system 120 with respect to the eye E. The split optical system projects a visual target (split visual target) for focusing the photographing optical system 120 on the eye E.

[Illumination optics]
The illumination optical system 100 includes an observation light source 101, a condenser lens 102, a photographing light source 103, a condenser lens 104, a filter unit 105, a ring translucent plate 107, a mirror 108, a black spot plate 109, an illumination stop 110, a relay lens 111, and a perforated mirror. 112 and an objective lens 113 are included.

  The observation light source 101 outputs steady light (continuous light) for observing the fundus oculi Ef with the naked eye or a captured image. The observation light source 101 includes, for example, a halogen lamp. The condenser lens 102 collects steady light (observation illumination light) emitted from the observation light source 101. The condenser lenses 102 and 104 collect the observation illumination light.

  The imaging light source 103 outputs flash light for imaging the fundus oculi Ef. The imaging light source 103 is constituted by a xenon lamp, for example. The condenser lens 104 condenses flash light (photographing illumination light) emitted from the photographing light source 103.

  The filter unit 105 is provided with an optical filter. As this optical filter, an exciter filter for FA (fluorescein fluorescence imaging; visible fluorescence imaging), an exciter filter for ICG (indocyanine green fluorescence imaging; infrared fluorescence imaging), an exciter filter for spontaneous fluorescence imaging, red There are filters for free photography.

  The filter unit 105 may be provided with a plurality of optical filters. In that case, for example, by moving the filter unit 105 by a driving mechanism, these optical filters are selectively arranged on the optical path.

  The ring translucent plate 107 is a plate-like member having a ring translucent portion 107a composed of an annular translucent region. The ring light transmitting plate 107 is disposed at a position conjugate with the pupil of the eye E to be examined. The ring light transmitting plate 107 is disposed so that the center of the ring light transmitting portion 107 a is positioned on the optical axis of the illumination optical system 100.

  The mirror 108 reflects observation illumination light and imaging illumination light in the optical axis direction of the imaging optical system 120. The black spot plate 109 has a light shielding region at the center thereof, and prevents the imaging devices 9 and 10 from detecting the reflected light of the illumination light from the objective lens 113.

  The illumination diaphragm 110 is a diaphragm member that shields the peripheral area of the illumination light. The illumination stop 110 is configured to be movable in the optical axis direction of the illumination optical system 100. Thereby, the illumination range of the fundus oculi Ef can be changed. Effects such as prevention of flare by the illumination stop 110 can be obtained.

  The perforated mirror 112 synthesizes the optical axis of the illumination optical system 100 and the optical axis of the photographing optical system 120. A hole 112 a is opened in the center region of the perforated mirror 112. The optical axis of the illumination optical system 100 and the optical axis of the photographing optical system 120 intersect at a substantially central position of the hole 112a. The objective lens 113 is provided in the objective lens portion 8 a of the main body portion 8.

[Photographing optical system]
The photographing optical system 120 will be described. The photographing optical system 120 includes an objective lens 113, a perforated mirror 112 (a hole portion 112a thereof), a photographing aperture 121, a filter portion 122, a focusing lens 124, a variable power lens 125, an imaging lens 126, a quick return mirror 127, and an imaging. The apparatus 9 is comprised.

  The fundus reflection light of the illumination light is emitted from the eye E through the central dark portion of the ring-shaped image formed in the pupil of the eye E as described above. The fundus reflection light emitted from the eye E enters the photographing aperture 121 through the hole 112a. At this time, the perforated mirror 112 reflects the corneal reflected light of the illumination light to prevent the occurrence of flare.

  The photographing aperture 121 is a plate-like member in which a plurality of circular translucent portions having different sizes are formed. The plurality of light-transmitting portions constitute apertures having different aperture values (F values). These light-transmitting portions are alternatively arranged on the optical path by a driving mechanism.

  The filter unit 122 is provided with an optical filter. Examples of the optical filter include a barrier filter for FA, a barrier filter for ICG, and a barrier filter for spontaneous fluorescence photography.

  The filter unit 122 may be provided with a plurality of optical filters. In this case, for example, the filter unit 122 is driven by a driving mechanism, and these optical filters are selectively arranged on the optical path. The filter units 105 and 122 are controlled in cooperation so that the corresponding filters are arranged on the optical path.

  The focusing lens (focus lens) 124 is moved in the optical axis direction of the photographing optical system 120 by the drive mechanism, and changes the focal position of the photographing optical system 120. The variable magnification lens 125 is moved in the optical axis direction by the drive mechanism to change the angle of view (magnification). The imaging lens 126 condenses the fundus reflection light from the eye E and forms an image on the image sensor 9 a of the imaging device 9.

  The imaging device 9 is used for color imaging of the fundus. The imaging device 9 receives fundus reflection light of photographing illumination light guided by the photographing optical system 120 and generates image data of each primary color component of R component, G component, and B component. The imaging device 9 includes, for example, a 3CCD type image sensor. The imaging device 9 combines the image data of these three primary color components to generate color image image data.

  The quick return mirror 127 is rotated around the rotation shaft 127a by the drive mechanism. When photographing the fundus with the imaging device 9, the fundus reflected light is guided to the imaging device 9 by jumping up the quick return mirror 127 obliquely provided on the optical path. On the other hand, at the time of fundus photographing with the imaging device 10 or fundus observation with the naked eye, the fundus reflected light is reflected upward while the quick return mirror 127 is obliquely arranged on the optical path.

  On the optical path of the fundus reflection light reflected by the quick return mirror 127, a field lens (field lens) 128, a switching mirror 129, an eyepiece lens 130, a relay lens 131, a reflection mirror 132, a photographing lens 133, and the imaging device 10 are provided. It has been.

  As with the quick return mirror 127, the switching mirror 129 is rotatable around the rotation shaft 129a. The switching mirror 129 is inclined on the optical path during naked eye observation, and reflects the fundus reflection light toward the eyepiece lens 130.

  Further, when a fundus image is captured using the imaging device 10, the switching mirror 129 is retracted from the optical path to guide the fundus reflected light toward the imaging element 10a. The fundus oculi reflection light is reflected by the reflection mirror 132 via the relay lens 131 and imaged on the image sensor 10 a by the photographing lens 133.

[Control system configuration]
A control system of the fundus imaging apparatus will be described. A configuration example of this control system is shown in FIG. The control system includes a control unit 210, a user interface (UI) 230, and an image processing unit 240. The control unit 210 and the image processing unit 240 are provided in the computer 200, for example. The user interface 230 is provided in the fundus camera body 1 and / or the computer 200. The focusing mechanism 124 </ b> A moves the focus lens 124 along the optical axis of the photographing optical system 120. The focusing mechanism 124A includes an actuator such as a stepping motor.

(Control part)
The control unit 210 controls each unit of the fundus imaging apparatus. For example, the control unit 210 controls turning on / off of the observation light source 101 and the imaging light source 103. In addition, the control unit 210 controls the exposure time (charge accumulation time), shooting sensitivity, and operation pixels of the imaging devices 9 and 10.

  In addition, the control object by the control part 210 is not limited to what is shown in FIG. For example, the control unit 210 controls a filter driving mechanism (not shown) to selectively place a plurality of optical filters provided in the filter units 105 and 122 on the optical path. When the filter is not used (for example, when color photographing is performed), the optical filter is retracted from the optical path.

  The control unit 210 includes a microprocessor, a storage device, and an interface for communicating with an external device. The storage device is a RAM, a ROM, a hard disk drive, or the like. The storage device stores in advance a computer program for causing the fundus imaging apparatus to execute operations characteristic of this embodiment. Further, the storage device stores various information such as a photographed fundus image, patient information, and photographing conditions.

[User interface]
The user interface 230 is provided with a display unit 231 and an operation unit 232.

(Display section)
The display unit 231 is controlled by the control unit 210 to display various screens and information. The display unit 231 includes a display device such as an LCD (Liquid Crystal Display). The display unit 231 includes, for example, a display device provided in the fundus camera main body 1, a display device of the computer 200, and the like.

(Operation section)
The operation unit 232 is used by an operator to operate the fundus imaging apparatus. The operation unit 232 includes operation devices and input devices provided in the retinal camera body 1, such as buttons, keys, a control panel 3a, a joystick 4, and operation buttons 4a. The control unit 232 includes an operation device and an input device provided in the computer 200, for example, a keyboard and a mouse.

(Image processing unit)
The image processing unit 240 performs various types of image processing on an image captured by the fundus imaging apparatus or an image acquired by an external apparatus. The image processing unit 240 includes a microprocessor and a storage device. A computer program is stored in the storage device in advance. The image processing unit 240 executes image processing according to this computer program. The image processing unit 240 is provided with an HDR processing unit 241.

  The HDR processing unit 241 performs high dynamic range imaging (abbreviated as HDR or HDRI) on a plurality of fundus images captured while changing the exposure. The HDR processing unit 241 is an example of an image generation unit.

  In general, HDR is a technique for generating an image having a wide dynamic range (so-called high dynamic range image) with little overexposure and blackout by combining a plurality of images obtained by shooting while changing exposure. is there. When displaying a high dynamic range image, tone mapping is performed to reduce the dynamic range. As a tone mapping technique, there are a technique for reducing the contrast of the entire image, a technique for locally reducing the contrast of the image, and the like. Note that HDR is described in, for example, JP-A-2006-87063.

[Operation]
The operation of the fundus imaging apparatus will be described. Hereinafter, processing for generating a fundus image by high dynamic range synthesis will be described as a first operation example. Furthermore, as a second operation example, a process of generating a fundus image by combining a plurality of images shot while changing the exposure and the focal position with a high dynamic range will be described.

[First operation example]
It is assumed that the apparatus optical system is aligned and focused on the eye E to be examined. When an instruction for photographing is given, the control unit 210 controls the illumination optical system 100 and the photographing optical system 120 to cause photographing of the fundus oculi Ef in the first exposure state. Similarly, the control unit 210 performs photographing of the fundus oculi Ef in each of the second exposure state, the third exposure state,..., The nth exposure state.

  Such continuous shooting is realized, for example, by linking (that is, synchronizing) the control that causes the shooting light source 103 to flash light a plurality of times at high speed and the control that switches the exposure state at high speed. The reason why these controls are performed at a high speed is, for example, to prevent positional deviation between images due to movement of the eye E (fixed eye movement, etc.).

  As exposure state switching methods, for example, there are the following first to fourth methods. As a first method, there is a change in intensity of illumination light. This includes a method of changing the output intensity of the photographing illumination light from the photographing light source 103 and a method of providing a dimming means on the optical path of the photographing illumination light. Examples of the dimming means include a filter and a diaphragm. As an example of the former, a configuration in which a plurality of filters having different light transmittances are sequentially inserted into the optical path can be applied. As an example of the latter, it is possible to apply a configuration in which a plurality of apertures having different aperture sizes are sequentially inserted into the optical path.

  As a second method, a configuration in which the irradiation time (that is, the output time) of photographing illumination light by the photographing light source 103 is changed can be applied. The same effect can be obtained even if a shutter is provided on the optical path of the photographic illumination light and the time for opening the shutter is changed.

  As a third method, a configuration in which the detection time of the fundus reflected light (that is, the charge accumulation time) is changed by controlling the image sensor 9a (or the image sensor 10a) can be applied.

  As a fourth method, a configuration in which the imaging sensitivity is changed by controlling the imaging device 9a (or the imaging device 10a) can be applied.

  The exposure may be changed by one of the first to fourth methods described above, or the exposure may be changed by combining two or more of these.

  The n images obtained by such continuous shooting are sent to the HDR processing unit 241. These images are obtained by photographing the fundus oculi Ef with different exposures. The HDR processing unit 241 generates a fundus image of a high dynamic range image by applying HDR to these images.

[Second operation example]
As described above, in this operation example, photographing is executed a plurality of times while synchronizing the change in exposure and the change in focus position. The exposure change is executed by sequentially switching the first exposure state to the nth exposure state, for example, as in the first operation example. On the other hand, the focus position can be changed by moving the focusing lens 124 by controlling the focusing mechanism 124A. The focusing lens 124 is sequentially moved from the first focusing position to the nth focusing position corresponding to the first exposure state to the nth exposure state.

  The change of the focal position is executed in a range corresponding to a range equal to or greater than the depth of the optic disc, for example. In other words, if both ends of the focal position change range are the first focus position and the nth focus position, the distance between these two focus positions is (in consideration of the imaging optical system 120) the optic disc. It is set to more than the depth. Note that the depth of the optic nerve head may be a general value (for example, an average value obtained clinically) or a value obtained in advance for each eye E to be examined. The depth of the optic disc of the eye E can be measured based on, for example, a tomographic image or a three-dimensional image of the fundus oculi Ef acquired by optical coherence tomography (OCT).

  Similarly, the exposure change range can be set to be greater than or equal to the range corresponding to the luminance range in the optic disc image. The luminance range in the optic disc image means, for example, the difference between the maximum value and the minimum value in the image region of the optic disc in the fundus image (note that it is desirable to exclude specific luminance due to noise) . This range of luminance may be a general value obtained clinically, or may be acquired in advance from a fundus image of the eye E to be examined. Further, the exposure range corresponding to the brightness range is, for example, a range in which the exposure at which the maximum value portion can be suitably drawn is minimized and the exposure at which the maximum value portion can be suitably drawn is a maximum value. Can be set.

  In addition, the brightness of the optic nerve head increases as the position becomes deeper. Therefore, assuming that the first focus position, the second focus position,..., The nth focus position in order from the shallow position to the deep position, the corresponding first exposure state and second exposure are set. The state,..., The nth exposure state is set so that the exposure gradually decreases. With the above preparation, the following processing is executed.

  It is assumed that the apparatus optical system is aligned with the eye E. Further, it is assumed that the focusing lens 124 is disposed at the first focusing position.

  When a photographing instruction is given, the control unit 210 controls the illumination optical system 100 and the photographing optical system 120 to perform photographing of the fundus oculi Ef in the first exposure state and the first in-focus position. Similarly, the control unit 210 operates in the second exposure state and the second in-focus position, in the third exposure state and the third in-focus position,..., The n-th exposure state and the n-th in-focus position. Shooting of the fundus oculi Ef is executed at the focal position.

  In such continuous shooting, for example, control for causing the photographing light source 103 to flash a plurality of times at high speed, control for switching the exposure state at high speed, and control for moving the focusing lens 124 at high speed are linked (that is, synchronized). ).

  The n images obtained by such continuous shooting are sent to the HDR processing unit 241. These images are taken at different depth positions of the fundus oculi Ef with different exposures. The HDR processing unit 241 generates a fundus image of a high dynamic range image by applying HDR to these images.

Note that a plurality of times of photographing may be performed for each in-focus position, and HDR may be executed for each in-focus position.
[Action / Effect]
The operation and effect of the fundus imaging apparatus as described above will be described.

  The fundus imaging apparatus is configured to acquire a plurality of images with different exposures by capturing the fundus oculi Ef multiple times while changing the exposure, and generate a fundus image by applying HDR to the plurality of images. ing. Accordingly, it is possible to obtain a fundus image in which various portions of the fundus oculi Ef are drawn with appropriate exposure.

  In addition, the fundus imaging apparatus captures the fundus oculi Ef a plurality of times while changing the exposure and the focal position in synchronization, and generates a fundus image by applying HDR to a plurality of images obtained thereby. It is configured as follows. Therefore, it is possible to obtain fundus images that are focused at various depths while drawing various portions of the fundus oculi Ef with appropriate exposure.

  A technique for synthesizing a plurality of images having different focal positions to obtain a pseudo depth of field is digital image processing called focus synthesis, multi-focus synthesis, multiple focus, or the like. This technique is described in, for example, Japanese Patent Application Laid-Open No. 2004-29537.

  Further, the fundus imaging apparatus is configured to change the focal position at least in the depth range of the optic nerve head and to change the exposure at least in a range corresponding to the luminance range in the image of the optic nerve head. . As a result, a fundus image with proper exposure and focus can be obtained over the entire depth of the optic disc. In addition, by changing the focus position and the exposure within a range exceeding the above range, it is possible to acquire a fundus image in which exposure is appropriate and / or in focus in a wider range of depth.

<Other embodiments>
In the above-described embodiment, an apparatus that captures the fundus multiple times while changing the exposure, particularly an apparatus that performs fundus imaging multiple times while changing both the exposure and the focal position has been described. In this embodiment, an apparatus that captures the fundus multiple times while changing the focal position will be described.

  The fundus imaging apparatus according to this embodiment has the same configuration as that of the above embodiment. However, the components that perform the exposure changing process and the process accompanying it are not essential in this embodiment. That is, the fundus imaging apparatus according to this embodiment is sufficient if it has the following configuration. In addition, the character string shown in the parenthesis in the next paragraph shows the corresponding part in the said embodiment.

  In the fundus imaging apparatus according to this embodiment, the illumination optical system (100) irradiates the fundus (Ef) of the eye to be examined (E) with illumination light. The photographing optical system (120) includes a focusing lens (124) for changing the focal position, and guides fundus reflection light of illumination light to the image sensor (9a and / or 10a). The control unit (120) controls the illumination optical system (100) and the photographing optical system (120) so that the fundus (Ef) is photographed a plurality of times while changing the focal position with respect to the fundus (Ef). The image generation unit (image processing unit 240) generates a fundus image by synthesizing a plurality of images with different focal positions obtained by a plurality of shootings. Note that the configuration of each unit and the processing executed by these units are the same as in the above embodiment. In particular, the image synthesis processing executed by the image generation unit is digital image processing called focus synthesis, multifocal synthesis, multiple focus, or the like.

  According to such a fundus imaging apparatus, it is configured to generate a fundus image by combining a plurality of images (each having a different depth of focus) captured while changing the focal position. It is possible to obtain fundus images in which various portions of the fundus are in focus.

  Note that the change range of the focal position can be arbitrarily set. For example, similar to the above-described embodiment, the focal position can be changed in the range of the depth of the optic nerve head (at least). In addition, when a range to be focused (for example, a depth range of a part to be observed in detail) is known in advance, it is possible to perform imaging by setting the range. In addition, the range to be focused may be a single range (a single connected range) or a plurality of ranges (a plurality of single connected ranges).

  Embodiment described above is only an example of the structure for implementing this invention, and does not limit this invention. A person who intends to implement the present invention can appropriately make arbitrary modifications within the scope of the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Fundus camera main body 9a, 10a Image pick-up element 100 Illumination optical system 103 Shooting light source 120 Shooting optical system 124 Focusing lens 124A Focusing mechanism 200 Computer 210 Control part 230 User interface 240 Image processing part 241 HDR processing part

Claims (5)

An illumination optical system for irradiating the fundus of the eye to be examined with illumination light;
An imaging optical system that guides fundus reflection light of the illumination light to an imaging device;
A control unit that controls the illumination optical system and the photographing optical system, and performs photographing of the fundus a plurality of times while changing exposure;
An image generation unit that generates a fundus image by performing high dynamic range composition on a plurality of images with different exposures obtained by the plurality of times of photographing;
A fundus photographing apparatus comprising: The photographing optical system includes a focusing lens for changing a focal position,
The control unit changes the focal position with respect to the fundus by controlling the focusing lens together with the change of the exposure in the plurality of times of photographing.
The fundus imaging apparatus according to claim 1. The control unit changes the focal position at least in a depth range of the optic disc, and changes the exposure in a range corresponding to a luminance range in an image of the optic disc at least.
The fundus imaging apparatus according to claim 2. The control unit is one of a change in intensity of the illumination light, a change in irradiation time of the illumination light, a change in detection time of the fundus reflected light by the image sensor, and a change in imaging sensitivity of the image sensor. Or change the exposure by a combination of two or more,
The fundus imaging apparatus according to any one of claims 1 to 3, wherein the fundus imaging apparatus is characterized. An illumination optical system for irradiating the fundus of the eye to be examined with illumination light;
An imaging optical system that includes a focusing lens for changing a focal position, and that guides fundus reflection light of the illumination light to an imaging device;
A control unit that controls the illumination optical system and the photographing optical system to change the focal position with respect to the fundus and perform photographing of the fundus a plurality of times;
An image generator that generates a fundus image by combining a plurality of images having different focal positions obtained by the plurality of times of photographing;
A fundus photographing apparatus comprising:

Images