JP2002345758A - Ophthalmic imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of three-dimensional information by precisely keeping the base line length of a non-simultaneous three-dimensional taken image and to improve the quality of image by preventing the shielding of light by an iris. SOLUTION: This device comprises a fundus oculi photographic means for taking the image of a fundus oculi through reflectors 1 and 2 deflectably arranged on the side closer to the eye E of a subject a subject eye from a photographic diaphragm 5; a fundus oculi lighting means for guiding the light from an observation light source 19 through the reflectors 1 and 2 to illuminate the fundus oculi; an anterior ocular segment imaging means for detecting the position of pupil Ep of the eye E of the subject an angle control means for controlling the direction of the reflectors 1 and 2 so that the image of the diaphragm 5 is projected to a prescribed position of the pupil Ep in conformation to the detected pupil position; a reflector angle control means for changing the direction of the reflectors 1 and 2 to two or more angles to change the projecting position of the diaphragm 5; and an emission control circuit 42 for emitting light from the light source 16 according to the two ore more angles of the reflectors 1 and 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic photographing apparatus used in an ophthalmic clinic or the like.

[0002]

2. Description of the Related Art Conventionally, as a stereoscopic imaging method for ophthalmology, 1
2. Description of the Related Art There has been known a device that projects an imaging aperture at two different points on a pupil during two imaging operations to capture two images.

[0003]

However, in the above-mentioned conventional example, since the stereoscopic imaging is not performed at the same time, if the subject's eye moves between the two images, a stereoscopic image having an accurate base line length is generated. There is a problem in that an image having uniform brightness cannot be obtained because the luminous flux is not obtained or an illuminating light beam is applied to the iris.

An object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide an ophthalmologic photographing apparatus capable of easily obtaining left and right stereoscopic images having different parallaxes.

[0005]

According to a first aspect of the present invention, there is provided an imaging system for photographing a fundus of a fundus through a reflecting mirror arranged to be deflected to the eye to be examined with respect to a photographing aperture. An illumination system that guides light from a light source to the fundus through the reflector to illuminate the fundus, a detector that detects the position of the pupil of the subject's eye, and an image of the photographic aperture is projected onto a predetermined position of the pupil. A drive mechanism for changing the direction of the reflecting mirror,
An ophthalmologic imaging apparatus, comprising: a control system that changes the direction of the reflecting mirror to a plurality of angles, changes a projection position of the imaging stop, and causes the light source to emit light according to the plurality of angles.

According to a second aspect of the present invention, there is provided the ophthalmologic photographing apparatus according to the first aspect, further comprising an optical system for projecting a fixation target onto a subject via the reflecting mirror.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is a configuration diagram of a fundus camera embodying the present invention. The main reflecting mirror 1 is disposed in front of the subject's eye E, and the sub-reflecting mirror 2 is provided in the direction of reflection of the main reflecting mirror 1. A dichroic mirror 3 for reflecting external light, a perforated mirror 4, a photographic stop 5 disposed in a hole of the perforated mirror 4, a focus lens 6, a photographic lens 7, a beam splitter 8, a color separation prism 9, an image sensor 10r, 10
The imaging mechanism 10 including g and 10b is arranged. And
An anterior ocular segment imaging means 11 is provided in the reflection direction of the dichroic mirror 3, and constitutes an eye pupil position detecting means of the eye to be examined together with anterior eye illumination light sources 12a and 12b which are provided diagonally ahead of the eye E and emit infrared light.

The fundus illumination system in the direction of incidence of the perforated mirror 4 includes a relay lens 13 from the perforated mirror 4 side, an infrared light cut filter 1 that can be inserted into and removed from the optical path and cuts infrared light.
4. A stop 15 having a ring-shaped opening, a photographing light source 16 composed of a strobe tube, a visible light cut filter 17 that blocks visible light and transmits infrared light, a condenser lens 18, an observation light source such as a halogen lamp that emits steady light. 19 are arranged.

In the incident direction of the beam splitter 8, a fixation target projecting means comprising a liquid crystal display element 20 arranged substantially conjugate with the fundus oculi and a backlight 21 for illuminating the liquid crystal display element 20 from the back is provided.

The respective outputs of the image pickup devices 10r, 10g, 10b are connected to image boards 31r, 31g, 31b via signal amplifier circuits 30r, 30g, 30b. The image boards 31r, 31g, and 31b include A / D converters 32r, 32g, and 32b for red, green, and blue signals, and a memory 33.
r, 33g, 33b, and image boards 31r, 3
The outputs of 1g and 31b are connected to the image control means 34.

A memory 34a, 3
4b and 34c are provided, and the image control means 34 is connected to the monitor 37 and the stereoscopic monitor 38 via the image recording means 35 and the video RAM 36. Further, the image control means 34 and the video RAM 36 are connected to the control means 39. The image recording means 35 includes MO, MD, DVD-RAM, VTR tape,
This is a drive device that writes or reads data to or from a recording medium D that can be stored and held without external power supply such as a hard disk.

The control means 39 is connected to a photographing switch 40 and a selection switch 41, and the control means 39 is connected to the photographing light source 16 via the anterior ocular segment photographing means 11 and the strobe light emission control circuit 42. The control unit 39 has a memory 3
9a, capacitors 42a and 42b for controlling the amount of emitted light are provided in the flash emission control circuit 42.

The main reflecting mirror 1 is a part of a quadratic curved surface having two focal points, the pupil Ep of the eye E to be examined and the image reflected by the sub-reflecting mirror 2 of the photographing stop 5, and a plane including the two focal points and the optical axis. It is rotatably supported by hinges 1a and 1b about a straight line formed by a tangent plane at a contact point between the quadratic curved surface and the optical axis as a rotation axis.
Motors 1c and 1d are arranged on the left and right back surfaces of the main reflecting mirror 1, and a gear (not shown) is mounted on the rotating shafts of the motors 1c and 1d. This gear controls the rotation angle of the main reflector 1 by converting the rotational motion of the rotating shafts of the motors 1c and 1d into axial motion and pushing and pulling the main reflector 1.

Similarly, the sub-reflecting mirror 2 is rotatably supported by hinges 2a and 2b with a rotation axis being a line perpendicular to the plane including the optical axis reflected by the sub-reflecting mirror 2 and passing through the reflection point of the optical axis. I do. The motor 2 is mounted on the back surface of the sub-reflector 2 in the vertical direction.
c and 2d are arranged, and a gear (not shown) is attached to the rotating shafts of the motors 2c and 2d. This gear converts the rotational movement of the rotating shaft of the motor into an axial movement, and controls the rotation angle of the main reflecting mirror 2 by pushing and pulling the sub-reflecting mirror 2.

Using this fundus camera, the fundus oculi E of the eye E to be examined
In the case of monocular photographing of r, the photographer selects the selection switch 41
Press the mono switch 41a, confirm that the camera is in the monocular imaging mode, seat the subject in front of the fundus camera, and observe the eye E and the fundus camera while observing the fundus Er with infrared light. Perform position adjustment.

In the observation state, the infrared light cut filter 14 is retracted outside the optical path. The light emitted from the observation light source 19 is condensed by the condenser lens 18, and only the infrared light is transmitted by the visible light cut filter 17.
6. Object reflection optics including the sub-reflection mirror 2 and the main reflection mirror 1, passing through the opening of the stop 15 having a ring-shaped aperture, passing through the relay lens 13, and being reflected upward by the mirror portion around the perforated mirror 3. The system illuminates the fundus Er through the pupil Ep of the eye E to be examined.

Thus, the fundus Er illuminated with infrared light
Image passes through the objective reflecting optical system, the photographing stop 5, the focus lens 6, and the photographing lens 7 again, and enters the color separation prism 9. The color separation prism 9 guides infrared light and red light to the image pickup device 10r, guides green light to the image pickup device 10g, and guides blue light to the image pickup device 10b. Since the light is infrared light, the image sensor 1
An image is formed at 0r and converted into an electric signal. This signal is amplified to a predetermined amplification rate through the signal amplification circuit 30r, is input to the image control means 34 through the image boards 31r, 31g, 31b, and is written into a portion of the video RAM 36 corresponding to the area 37a of the monitor 37, The image is displayed on an area 37 a of the monitor 37.

Further, an image of the anterior segment of the subject's eye E is also projected on the area 37b on the monitor 37. Anterior segment illumination light source 12
The near-infrared light having a wavelength of, for example, 720 nm emitted by a and 12b illuminates the anterior segment of the eye E to be examined. The illuminated image of the anterior segment is reflected by the main reflecting mirror 1 and the sub-reflecting mirror 2, reflected again by the dichroic mirror 3, and forms an image on the imaging surface of the anterior segment imaging unit 11. This signal is supplied to the A / D converter 32
r, converted to a digital signal,
The data is written in the area corresponding to the monitor 37b of M36.
Accordingly, the monitor 37 displays the anterior segment of the eye E and the fundus E
r image is projected simultaneously.

The control means 39 confirms that the angles of the reflecting mirrors 1 and 2 are at the initial neutral positions, and detects the pupil position of the eye E from the signal output from the imaging means 11. In the anterior segment images illuminated by the anterior segment illumination light sources 12a and 12b, the image of the pupil Ep appears dark. That is, the image is binarized, and a continuous portion lower than a certain value is recognized as the pupil Ep, and the position of the pupil Ep is detected.

The control means 39, which recognizes that the position of the pupil Ep has entered the position adjustable range by the reflecting mirrors 1 and 2,
Start auto alignment. The control means 39 controls the pupil E
When it is determined that p is eccentric downward, the motor 2d is driven in a direction to push the sub-reflecting mirror 2 from the back surface, and further, the motor 2c is driven in a direction to pull the sub-reflecting mirror 2 from the back surface. 2b rotates about a rotation axis. When the control means 39 determines that the position of the pupil Ep is eccentric to the left or right, the motors 1c and 1d are driven, and the hinges 1a and 1d are driven.
The main reflecting mirror 1 is rotated about 1b as a rotation axis. The control means 39 repeats this operation until the pupil image is arranged at a predetermined position in the center of the image sensor 32. In this way, the positioning is always performed so that the photographing optical axis passes through the center of the pupil Ep.

Further, once the pupil Ep enters a predetermined range,
If the position of the eye E is largely changed due to the start of the auto-alignment, and there is no room for adjustment in the angles of the reflecting mirrors 1 and 2 and the position cannot be adjusted, the monitor 37 is used.
Characters such as the indicators 37c and 37d are displayed above. For example, when the optotype 37d, which is a left-pointing arrow, is displayed, the photographer moves the optical system to the left using operating means (not shown), and the optotype 37c, which is an upward-pointing arrow, is displayed. Moves the optical system upward using operating means (not shown). Since the fine movement is automatically tracked by driving the reflecting mirrors 1 and 2, these operations may be relatively slow.

It is more preferable that the direction in which the optical system is moved is indicated on the monitor 37 so that the main reflecting mirrors 1 and 2 can be photographed at the neutral position as much as possible.

During the positioning operation, the subject looks at the fixation target. The liquid crystal display element 20 has one transmissive portion, and the image of the transmissive portion becomes a fixation target. That is, the image of the transmitting portion of the liquid crystal display element 20 illuminated by the backlight 21 is reflected by the beam splitter 8, passes through the taking lens 7, the lens 6, and the taking stop 5, passes through the dichroic mirror 3, and passes through the sub-reflecting mirror. 2. The light is reflected by the main reflecting mirror 1 and projected on the fundus Er via the pupil Ep. The rotational position of the reflecting mirrors 1 and 2 accompanying the alignment of the pupil Ep also changes the position at which the fixation target is projected.

However, since the fixation target position does not change with respect to the image pickup mechanism 10, the photographing range does not change as long as the subject fixes the fixation target. That is, the fixation target equivalent position of the imaging mechanism 10 always corresponds to the substantially macula position of the eye E. Therefore, by rotating and driving the reflecting mirrors 1 and 2, the pupil Ep and the photographic optical axis can be aligned without changing the photographic range.

The photographer adjusts the working distance between the subject's eye E and the optical system so that the contrast of the iris pattern of the anterior eye image displayed on the monitor 37 is optimized, and focuses on the fundus image. Check the shooting range, flare, eyelashes, etc.

After the above-mentioned preparation for photographing is completed, the photographing switch 40 is operated to photograph a still image. Shooting switch 40
The control means 39 having detected the input to the controller inserts the infrared light cut filter 14 for blocking the infrared light into the optical path, starts the light accumulation of the image pickup devices 10r, 10g, and 10b. Sends a light emission signal and shoots.

A strobe light emission control circuit 4 which has received a light emission signal
2 sends a trigger signal to the photographing light source 16,
The electric charge stored in 2a is discharged to emit light. Shooting light source 16
Is transmitted through the aperture of the stop 15 having a ring-shaped aperture, the infrared light is removed by the infrared light cut filter 14, and the remaining visible light is
3, the light is reflected upward by a mirror unit around the perforated mirror 3, and passes through the sub-reflection mirror 2 and the main reflection mirror 1.
The fundus Er is illuminated via p.

The image of the fundus illuminated in this way is the pupil Ep.
Through the main reflecting mirror 1, the sub-reflecting mirror 2, the photographic stop 5, the focus lens 6, and the photographic lens 7 again, enter the color separation prism 9, and are separated into red, green, and blue, respectively.
An image is formed on the imaging elements 10r, 10g, and 10b, and is converted into an electric signal. The signal amplifier circuits 30r, 30g, 30b
The color balance is adjusted by amplifying these signals at a predetermined amplification rate for each color, and the image boards 31r, 31
g and 31b convert the electric signals into digital image data by A / D converters 32r, 32g and 32b.
3r, 33g, and 33b.

The image data is corrected for distortion by the image control means 34 in accordance with the pattern stored in the memory 34a, and is recorded on the recording medium D by the image recording means 35.
Is written in a portion corresponding to the area 37a of the monitor 37.
Is displayed in the area 37a. The control means 39 separates the infrared light cut filter 14 from the optical path, returns the position of the main reflecting mirror 1 to the initial position without inclination, and ends the photographing.

FIG. 2 is a flowchart showing the flow of the operation described above.

Next, a case of performing three-dimensional photographing using the present apparatus will be described. When performing stereoscopic photography, the stereo switch 41b of the selection switch 41 is pressed. Switch 41
The control means 39 which has detected the input to b charges both the capacitors 42a and 42b of the strobe light emission control circuit 42 and sets the angles of the main reflecting mirrors 1 and 2 to the initial neutral position. The photographer sits the subject in front of the fundus camera, and positions the eye E and the fundus camera while observing the fundus Er using infrared light.

The light emitted from the observation light source 19 is condensed by the condenser lens 18, only the infrared light is transmitted by the visible light cut filter 17, and passes through the photographing light source 16 and the aperture of the stop 15 having a ring-shaped aperture. , Through the lens 13,
An objective reflecting optical system which is reflected upward by a mirror portion around the perforated mirror 3 and includes a sub-reflecting mirror 2 and a main reflecting mirror 1;
The fundus Er is illuminated through the pupil Ep.

The image of the fundus Er illuminated with the infrared light in this way passes through the reflecting mirrors 1 and 2 of the objective reflecting optical system, the photographing stop 5, the focus lens 6 and the photographing lens 7 again, and passes through the color separating prism 9. The light enters, forms an image on the image sensor 10r, and is converted into an electric signal. This signal is amplified to a predetermined amplification rate by the signal amplification circuit 30r, and is input to the image control means 34.
The data is written to a portion of the video RAM 36 corresponding to the area 37a of the monitor 37, and is displayed on the area 37a of the monitor 37. Note that an anterior segment image of the subject's eye E is also projected on the area 37b on the monitor 37, as in the case of monocular photography.

The control means 39 similarly controls the anterior ocular segment imaging means 11
, The position of the pupil Ep is detected. As described above, since the image of the pupil Ep appears dark in the anterior segment images illuminated by the anterior segment illumination light sources 12a and 12b, the image is binarized and the position of the pupil Ep is detected.
When the control means 39 recognizes that the position of the pupil has entered the range in which the position can be adjusted by the reflection images 1 and 2, the automatic alignment is started using the reflection mirrors 1 and 2 as described above.

The photographer looks at the image of the anterior segment on the area 37b of the monitor 37 and operates the optical system using operating means (not shown) so that the pupil Er of the eye E and the index 37e are concentric. The optical system is aligned vertically, horizontally, and further, and the optical system is aligned in the optical axis direction such that the pattern of the iris of the subject is best focused. Further, the operator observes the fundus image reflected on the area 37a of the monitor 37, moves the focus lens 6 to focus, and further confirms the photographing range.

After the preparation for photographing is completed, the photographing switch 40 is operated to perform stereoscopic photographing. The control unit 39 that has detected the input to the photographing switch 40 inserts the infrared light cut filter 14 that blocks infrared light into the optical path. And
The motors 1a and 1b are controlled to set the angle of the main reflecting mirror 1 so that the image of the photographing diaphragm 5 is projected eccentrically by a predetermined amount with respect to the center position of the pupil Ep detected by the pupil position detecting means. Then, light accumulation of the image sensors 10r, 10g, and 10b is started, a light emission signal is sent to the strobe light emission control circuit 42, and the first three-dimensional imaging is performed.

FIG. 3 shows the positional relationship between the pupil Ep and the aperture 15 when the alignment is completed.
The image 15 ′ of 5 is arranged concentrically. At this time, the main reflecting mirror 1 is at the initial position and is not inclined with respect to the rotation axis.

FIG. 4 shows the positional relationship between the pupil Ep and the diaphragm 15 at the first mirror angle of the main reflecting mirror 1 for stereoscopic photography.
The position of the stop image 15L 'on the pupil Ep is eccentric to the left. FIG. 5 shows the positional relationship between the pupil Ep and the diaphragm 15 at the second mirror angle of the main reflecting mirror 1 for stereoscopic photography, and the position of the diaphragm image 15R 'is eccentric to the right on the pupil Ep.
4 relative to the position of the stop image 5R 'in FIG.
The amount of eccentricity of L 'corresponds to the base line length.

Strobe light emission control circuit 4 which receives a light emission signal
2 sends a trigger signal to the imaging light source 16 to discharge the charge stored in the first capacitor 42a, and the imaging light source 16 emits light. The luminous flux emitted from the photographing light source 16 passes through the opening of the aperture 15 having a ring-shaped opening similarly to the observation light, the infrared light is removed by the infrared light cut filter 14, and the remaining visible light passes through the relay lens 13. As shown in FIG. 4, the light is reflected upward by the mirror part around the perforated mirror 3 and passes through the sub-reflection mirror 2 and the main reflection mirror 1 from a position 15L eccentric to the left of the center of the pupil Ep as shown in FIG. To illuminate.

The image of the fundus Er illuminated in this way passes through the image forming position 5'L of the photographic stop 5 eccentric to the left of the center of the pupil Ep as shown in FIG. The light passes through the sub-reflection mirror 2, the photographing aperture 5, the focus lens 6, and the photographing lens 7, enters the color separation prism 9, is separated into red, green, and blue, and is divided into image pickup devices 10r, 10g, and 1g.
0b and is converted into an electric signal. Signal amplification circuit 3
0r, 30g, and 30b adjust the color balance by amplifying these signals at a predetermined amplification rate for each color,
The image boards 31r, 31g, and 31b are A / D converters 32.
r, 32g, and 32b convert the electric signals into digital image data, and store the memories 33r and 33 in the image board 9.
g, 33b, and the image data is corrected by the image control means 34 in accordance with the pattern stored in the memory 34a, and stored in the memory 34b of the image control means 34.

Next, the second image is photographed by stereoscopic photographing. The control means 39 detects the pupil Ep by the pupil position detecting means.
Of the diaphragm 15 is detected, and the center position of the
The main reflecting mirror 1 is set at the second mirror angle so as to be decentered by a predetermined amount with respect to 5 ′,
Discharges the charge stored in the condenser 42b of the imaging light source 1
6 emits light. The light emitted from the photographing light source 16 passes through the same optical path as before, and illuminates the fundus Er from a position 15′R eccentric to the right side of the center of the pupil Ep as shown in FIG.

The fundus image illuminated in this way passes through the image forming position 5'R of the photographing diaphragm 5 eccentric to the right side of the center of the pupil Ep as shown in FIG. The light passes through the mirror 2, the photographic stop 5, the focus lens 6, and the photographic lens 7, enters the color separation prism 9, and is similarly separated by color.
The image data is converted into digital image data and stored in the memories 33r, 33
g, 33b, and their image data are stored in the memory 34.
The image distortion is corrected in accordance with the pattern stored in a, and stored in the memory c of the image control means.

The memory 34 of these image control means 34
The images stored in b and 35c are recorded on the recording medium D by the image recording means 35, further written in a portion corresponding to the area 37a of the video RAM 36, and displayed independently on the areas 37a and 37b on the monitor 37. At the same time, the data is also written to two corresponding areas of the video RAM 36 for a stereo monitor, and is displayed on the stereoscopic monitor 38 in three dimensions. By viewing the image reflected on the monitor 38, the photographer can immediately observe the fundus stereoscopically without using glasses. Further, by viewing the left and right images independently reflected on the monitor 37, it is possible to confirm the flare and the brightness difference between the images.

The control means 39 returns the position of the main reflecting mirror 1 to the initial position without inclination, detaches the infrared light cut filter 14 out of the optical path, and ends the photographing.

FIG. 6 is a flowchart showing the flow of the above-described photographing.

[0046]

As described above, the ophthalmologic photographing apparatus according to the present invention detects the position of the pupil of the eye to be inspected, and provides means for decentering the photographing aperture with reference to the detected position. 3D images can be shot twice consecutively and non-simultaneously, and even if the subject's eye moves during the two shots, the base line length can be accurately maintained, enabling accurate 3D shooting. become.

Further, the ophthalmologic photographing apparatus according to the present invention can photograph without illuminating the iris and the like, so that an image with uniform brightness can be obtained, the accuracy of diagnosis is improved, and the efficiency of photographing is improved. I do.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a fundus camera.

FIG. 2 is a flowchart of the operation.

FIG. 3 is an explanatory diagram of a relationship between a pupil and an aperture.

FIG. 4 is an explanatory diagram of a relationship between a pupil and an aperture.

FIG. 5 is an explanatory diagram of a relationship between a pupil and an aperture.

FIG. 6 is a flowchart of the operation.

[Explanation of symbols]

 Reference Signs List 1 main reflecting mirror 2 sub-reflecting mirror 3 dichroic mirror 4 perforated mirror 5 shooting aperture 6 focus lens 7 shooting lens 8 beam splitter 9 color separation prism 10 imaging mechanism 10r, 10g, 10b imaging element 11 anterior ocular segment imaging means 12a, 12b Anterior segment illumination light source 14 Infrared light cut filter 15 Aperture 17 Visible light cut filter 16 Imaging light source 19 Observation light source 30 Signal amplification circuit 31 Image board 32 Memory 36 Video RAM 34 Image control means 35 Image recording means 37 Monitor 38 Stereoscopic monitor 39 Control means 40 Shooting switch 41 Selection switch 42 Strobe light emission control circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference)

Claims (2)

[Claims] 1. A photographing system for photographing the fundus via a reflecting mirror arranged to be deflected closer to the eye to be examined than a photographing aperture, and an illumination for illuminating the fundus by guiding light from a light source to the fundus via the reflecting mirror. System, a detector that detects the position of the pupil of the subject's eye, a drive mechanism that changes the direction of the reflecting mirror so that the image of the photographic aperture is projected onto a predetermined position of the pupil, and the direction of the reflecting mirror. An ophthalmologic photographing apparatus, comprising: a control system that changes the projection position of the photographing aperture by changing the angle to a plurality of angles and causes the light source to emit light according to the plurality of angles. 2. The ophthalmologic photographing apparatus according to claim 1, further comprising an optical system that projects a fixation target onto a subject via the reflecting mirror.