JP2005087300A - Ophthalmologic photographing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ophthalmologic photographing apparatus taking an image of the fundus oculi of a favorable image quality in a short period of time regardless of the state of the pupil. <P>SOLUTION: This ophthalmologic photographing apparatus includes a lighting optical system lighting the frontal eye part of an eye to be examined, a photographing means taking the image of the frontal eye area lit by the lighting optical system, a dimension information extracting means extracting information corresponding to the dimension of the pupil part from the frontal eye image taken by the photographing means, and a gain setting means setting a gain of the photographing means taking the image of the eye to be examined based on the dimension information extracted by the dimension information extracting means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ophthalmologic photographing apparatus that photographs the fundus of a subject's eye, for example.

  Cardiovascular diseases are mentioned as a characteristic of adult diseases represented by diabetes and hypertension, and fundus photography has been conventionally performed as an inspection method for these diseases. There are two types of fundus photography: mydriatic photography that presumes the use of mydriatic agents and non-mydriatic photography that does not involve the use of mydriatic agents. In adult medical examinations, examinations using non-mydriatic photography are generally performed.

  In the case of non-mydriatic photography, there is a problem that the image quality of the photographed image greatly depends on the pupil diameter of the eye to be examined. As a solution to this problem, Patent Document 1 proposes a method of photographing at a timing while observing a variation in the size of the pupil region.

Japanese Examined Patent Publication No. 63-51020

  However, in the case of observing changes in the size of the conventional pupil area, it is not possible to perform imaging until a certain condition is met. In group screenings that would not be possible, the imaging efficiency had declined.

  Further, since the pupil enlargement was in the range of natural mydriasis, a sufficient amount of photographing light could not be obtained from the eye to be examined with a small pupil originally, and it was photographed as a dark image.

  An object of the present invention is to provide an ophthalmologic photographing apparatus capable of solving the above-described problems and photographing a fundus image having a good image quality in a short time regardless of the state of the pupil.

  To achieve the above object, the present invention provides an illumination optical system that illuminates the anterior segment of the eye to be examined, an imaging unit that images the anterior segment region illuminated by the illumination optical system, and an image captured by the imaging unit. Size information extracting means for extracting information corresponding to the size of the pupil from the anterior eye image, and gain of the imaging means for imaging the eye to be examined based on the size information extracted by the size information extracting means The ophthalmologic photographing apparatus is configured to include a gain setting means for setting.

  Further, the present invention provides an illumination optical system that illuminates the anterior segment of the eye to be examined, an imaging unit that captures an anterior segment area illuminated by the illumination optical system, and an anterior segment image captured by the imaging unit. Size information extracting means for extracting information corresponding to the size of the pupil part, and imaging light quantity for setting the imaging light quantity when imaging the eye to be examined based on the size information extracted by the size information extracting means An ophthalmologic photographing apparatus is configured including setting means.

  According to the present invention, since the imaging gain or the amount of imaging light is set based on the pupil diameter, the eye to be inspected can be easily and quickly imaged even in a scene in which imaging time such as group examination is regarded as important. It can be performed.

  Further, even with a small pupil eye, a high-quality eye image can be obtained.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
Embodiment 1 of the present invention will be described in detail with reference to the device configuration diagrams and flowcharts shown in FIGS.

  FIG. 1 shows an apparatus configuration diagram when the present invention is implemented. 1 is a light source for observation / alignment such as a lamp, 2 is a visible cut filter that transmits infrared light, 3 is a condenser lens, 4 is a strobe light source, etc. Still image photographing light source, 5 is a relay lens, 6 is a perforated mirror, E is an eye to be examined, 7 is an objective lens, 8 is an anterior ocular segment observation lens that is inserted into the optical path during anterior ocular segment observation, and 9 is a synthesizing lens. A lens system having a focusing function, 10 is a flip-up mirror that jumps upward on the right end in the drawing, 11 is a photographing sensor unit, 12 is a lens, 13 is an observation sensor unit, 14 is an observation image monitor, 15 Is a pupil diameter calculation unit, 16 is a gain instruction unit, 17 is a captured image recording unit, and 18 is a captured image monitor.

  Prior to imaging, first, rough alignment between the eye to be examined and the objective lens 7 is performed (step 1).

  Infrared light emitted from an infrared light source (not shown) for illuminating the anterior segment illuminates the anterior segment of the eye E, and the reflected light from the anterior segment is observed by the objective lens 7 and the anterior segment observation. The light is reflected by the flip-up mirror 10 through the lens 8, the hole of the perforated mirror 6 and the lens system 9, and is guided to the observation sensor unit 13 via the lens 12. The anterior ocular segment observation image photoelectrically converted by the observation sensor unit 13 is displayed on the observation image monitor 14.

  An example of an anterior segment image displayed on the observation image monitor 14 is shown in FIG. The photographer performs alignment by moving a stage unit (not shown) equipped with the optical system shown in FIG. 1 while viewing the anterior eye image.

  After the alignment is completed, the photographer presses an anterior eye / fundus changeover switch (not shown). Thereby, the pupil diameter calculation unit 15 performs A (analog) / D (digital) conversion on the anterior segment image obtained by the observation sensor unit, and then records the image on a memory (not shown). After recording, the anterior ocular segment observation lens 8 inserted in the optical path is removed from the optical path.

  Here, the case where an anterior ocular segment image is recorded in a memory by depressing the anterior ocular segment / fundus switching switch has been described as an example. The image may be recorded in a memory.

  Next, the pupil diameter of the eye to be examined is measured using the anterior segment image recorded in the memory (step 2).

  The anterior segment image stored in the memory is also recorded as the image shown in FIG. 3 in the same manner as the anterior segment image displayed on the observation image monitor 14. In FIG. 3, the pupil part can be extracted as a part having the highest density in the image. Therefore, the pupil part can be extracted by binarization processing using an appropriate threshold value. The pupil diameter shown in FIG. 4 is measured from the extracted pupil image. It is possible to calculate the diameter from the binarized circle by a known method.

  Here, an example is given in which the calculation is performed after extracting the pupil part image. However, the present invention is not limited to this, and the anterior eye part image on the memory is scanned in the direction of the arrow as shown in FIG. It may be configured to calculate the part having the longest connection of the pixel values as the pupil diameter.

  Although the method for calculating the pupil diameter using the anterior segment digital image recorded in the memory is described here, the pupil diameter may be extracted by a method using an analog electrical signal described in Japanese Patent Publication No. 63-21020.

  When the pupil diameter is obtained, an imaging gain value corresponding to the pupil diameter is calculated as shown in FIG. 6 (step 3).

  In general, in an optical system of a fundus camera, since illumination light enters the eye to be examined from around the pupil, in the case of a small pupil, the illumination light does not sufficiently enter the eye to be examined, resulting in insufficient light intensity. Therefore, when the pupil diameter is small, it is preferable to increase the imaging gain value, and conversely, when the pupil diameter is large, it is preferable to set the imaging gain small.

  In addition to simply determining the magnitude of the imaging gain according to the pupil diameter, it is also possible to set as shown below.

1. In accordance with the set pupil diameter, the distance range from the center position (optical axis) on the imaging surface of the imaging sensor unit 11 is determined as the imaging gain change range. Specifically, the change range of the imaging gain is set so that the range (circle area) from the imaging surface center position increases as the pupil diameter decreases.
[Example]
1. pupil diameter 5 → distance 1 from the center position on the imaging surface → imaging gain change range within circle with radius 1 pupil diameter 3 → distance 2 from center position on the imaging surface → imaging gain change range within circle with radius 2 The value of the imaging gain is changed according to the distance from the center position on the imaging surface. Specifically, it is set so that the value of the imaging gain is smaller in the peripheral portion than in the center position.
[Example]
Distance from the center position on the imaging surface 1 → imaging gain value 12
Distance from the center position on the imaging surface 2 → imaging gain value 6
Although the above 1 and 2 have been described as individual setting methods here, these can also be used in combination.

  Here, the case where the imaging gain value is set according to the pupil diameter has been described as an example. However, the present invention is not limited to this, and the imaging gain may be set based on the area in the pupil.

  The set imaging gain is set in the imaging sensor unit 11 in accordance with an instruction from the gain instruction unit 16.

  When the anterior ocular segment observation lens 8 is removed from the optical path, the photographer performs the identification of the imaging region, the adjustment of the imaging light amount, the focus adjustment, etc. while observing the fundus region of the eye to be examined with the observation image monitor (step 4). ).

  The illumination light emitted from the observation / alignment light source 1 is converted into light having a wavelength only in the infrared region by the visible cut filter 2, and then the mirror of the perforated mirror 6 through the condenser lens 3 and the relay lens 5. The eye fundus of the eye E is illuminated through the objective lens 7. Reflected light from the fundus is again passed through the objective lens 7, reflected by the flip-up mirror 10 through the hole of the perforated mirror 6 and the lens system 9, and guided to the observation sensor unit 13 via the lens 12. . The fundus oculi observation image photoelectrically converted by the observation sensor unit 13 is displayed on the observation image monitor 14.

  When preparation for photographing the fundus of the eye to be examined is completed, the photographer presses a photographing switch (not shown) (step 5).

  When the photographing switch is pressed, the still image photographing light source 4 is turned on, and the illumination light from the still image photographing light source 4 is reflected by the mirror portion of the perforated mirror 6 via the relay lens 5 and passes through the objective lens 7. Then, the fundus of the eye E is illuminated. The reflected light from the fundus is again passed through the objective lens 7 and is led to the photographing sensor unit 11 by the flip-up mirror 10 being flipped up through the hole of the perforated mirror 6 and the lens system 9 (step 6). ).

  The fundus image of the subject's eye imaged by the imaging sensor unit 11 is photoelectrically converted, A / D converted by the captured image recording unit 17 and recorded in a memory (not shown) at the same time on the captured image monitor 18. Displayed (step 7).

<Embodiment 2>
In the first embodiment, the imaging gain is set by the eye pupil diameter to be examined. However, the present invention is not limited to this, and the imaging light amount value is set by the eye pupil diameter as shown in the flowchart of FIG. May be.

  In this case, when the pupil diameter is small, the photographing light amount value is set to be large, and when the pupil diameter is large, the photographing light amount value is set to be small.

  In the above embodiment, the case of a fundus camera has been described as an example. However, the present invention is not limited to this, and the same effect can be obtained in other ophthalmologic photographing apparatuses such as a slit lamp (slit lamp microscope). Needless to say.

It is an apparatus block diagram of this invention. It is a flowchart which shows the operation | movement flow of Embodiment 1 of this invention. It is a figure which shows the example of an anterior segment image. It is a figure which shows the example of a pupil diameter. It is a figure which shows the pupil diameter extraction example. It is a figure which shows the example which showed the correspondence of a pupil diameter and imaging gain. It is a flowchart which shows the operation | movement flow of Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source for observation / alignment 2 Visible cut filter 3 Condenser lens 4 Light source for still image photography 5 Relay lens 6 Perforated mirror 7 Objective lens 8 Lens for anterior eye observation 9 Lens system 10 Bounce mirror 11 Shooting sensor unit 12 Lens DESCRIPTION OF SYMBOLS 13 Observation sensor unit 14 Observation image monitor 15 Pupil diameter calculation part 16 Gain instruction | indication part 17 Captured image recording part 18 Captured image monitor

Claims (4)

  An illumination optical system that illuminates the anterior segment of the eye to be examined, an imaging unit that captures an anterior segment region illuminated by the illumination optical system, and the size of the pupil from the anterior segment image captured by the imaging unit Size information extracting means for extracting corresponding information, and gain setting means for setting the gain of the imaging means for imaging the eye to be examined based on the size information extracted by the size information extracting means Ophthalmic imaging device.   An illumination optical system that illuminates the anterior segment of the eye to be examined, an imaging unit that captures an anterior segment region illuminated by the illumination optical system, and the size of the pupil from the anterior segment image captured by the imaging unit Size information extracting means for extracting corresponding information, and imaging light quantity setting means for setting an imaging light quantity when imaging the eye to be examined based on the size information extracted by the size information extracting means. A characteristic ophthalmologic photographing apparatus.   The ophthalmologic photographing apparatus according to claim 1, wherein the size information is a pupil diameter.   The ophthalmologic photographing apparatus according to claim 1, wherein the size information is an area in the pupil.

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