JP2005087546A - Ophthalmologic photographing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ophthalmologic photographing apparatus permitting the photography for a subject with a small pupil diameter. <P>SOLUTION: The ophthalmologic photographing apparatus comprises a fundus oculi illuminating means with a shading area with different length in a main longitudinal direction and in the direction perpendicular to the direction disposed around the front of a subject eye for illuminating the fundus oculi of the subject eye via a shading means rotatable around an optical axis, a photographing means for photographing the image of the fundus oculi to obtain a plurality of images corresponding to the different angles of rotation of the shading means, and an image synthesizing means for preparing one image from the plurality of images. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ophthalmologic photographing apparatus used in an ophthalmic clinic or the like.

  Conventionally, in order to separate an imaging light beam and an illumination light beam in the vicinity of the anterior eye portion of the eye to be examined, an image is formed on the illumination optical system of the fundus camera near the eye pupil of the eye to be examined, and further, for example, near the rear surface of the crystalline lens. A light-shielding stop having a light-shielding region around the optical axis and having a ring-shaped opening is provided.

  Therefore, when the pupil diameter of the subject is larger than the light shielding area, an image with appropriate brightness can be obtained. However, the illumination light flux is limited by the iris for the subject whose pupil diameter is smaller than the light shielding area. The vicinity of the center of the fundus image becomes dark. Therefore, when photographing a subject eye having a small pupil diameter by providing different sizes of light-shielding stops, the photographing is performed by replacing the light-shielding diaphragm with a small light-shielding area.

Japanese Patent Laid-Open No. 05-015497 JP 05-199997 A JP 05-305059 A

  However, in the above-described conventional example, since the separation range of the photographing light beam and the illumination light beam is reduced by reducing the size of the light-shielding diaphragm, flare is generated around the fundus image, and the image quality of the peripheral portion is deteriorated. However, there was a problem that fundus findings could not be obtained due to overlapping with the flare.

  An object of the present invention is to provide an ophthalmologic photographing apparatus that solves the above-described problems and can photograph even a subject having a small pupil diameter.

  In order to achieve the above object, an ophthalmologic photographing apparatus according to claim 1 has a light-shielding region having a length different between a main meridian direction and a vertical direction arranged in the vicinity of an anterior eye portion to be examined, and having an optical axis as a center. A fundus illuminating unit that illuminates the fundus of the subject's eye via a light-shielding unit that is rotatably arranged, an imaging unit that captures a fundus image corresponding to different rotation angles of the light-shielding unit, and obtains a plurality of images; It is characterized by having an image composition means for creating one image from these images.

  The ophthalmologic photographing apparatus according to claim 2 has a common main meridian direction arranged in the vicinity of the anterior eye portion of the eye to be examined, and has light-shielding areas having different lengths in the main meridian direction and the vertical direction thereof. A plurality of light-shielding means arranged so as to be rotatable about the optical axis at the same rotational speed, and the fundus illumination means for illuminating the fundus of the eye to be examined through these diaphragms, and the light-shielding means at different rotation angles Correspondingly, the image processing apparatus includes an imaging unit that captures a fundus image to obtain a plurality of images, and an image synthesis unit that creates one image from the plurality of images.

  According to the present invention, a plurality of images are photographed while rotating a diaphragm having light shielding regions having different lengths in the main meridian direction and a meridian direction perpendicular to the main meridian direction. By synthesizing the fundus image, a good image can be obtained even for a subject having a small pupil diameter, so that the efficiency of imaging can be increased.

  The present invention will be described in detail below based on the embodiments shown in the drawings.

  FIG. 1 is a configuration diagram of a fundus camera embodying the present invention.

  In front of the eye E, the objective lens 1, the perforated mirror 2, the photographing aperture 3, the focus lens 4, the photographing lens 5, the color separation prism 6, the image sensors 7r, 7g, An imaging mechanism consisting of 7b is arranged.

  The fundus illumination system in the incident direction of the perforated mirror 2 has different lengths in the main meridian direction projected from the perforated mirror 2 side to the vicinity of the cornea and the direction perpendicular thereto as shown in FIG. The corneal diaphragm 9 is a diaphragm having a light-shielding region including the optical axis, the relay lens 10, the infrared light cut filter 11 that can be inserted into and removed from the optical path and cuts infrared light, and the back surface of the eye lens to be examined, similar to the corneal diaphragm. As shown in FIG. 2 (B), which is projected in the vicinity, the lens diaphragm 12 which is a diaphragm having a light-shielding region having different lengths in the main meridian direction and the vertical direction thereof, and in the vicinity of the pupil of the eye to be examined (FIG. 2 (C)). As shown in FIG. 2, an observation light source such as a pupil stop 13 which is a stop having light-shielding regions with different lengths in the main meridian direction and a direction perpendicular thereto, an imaging light source 14 composed of a strobe tube, a condenser lens 15, and a halogen lamp for emitting steady light 16 Column. The main meridian directions of the diaphragms 9, 12, and 13 are coincident with each other, and the rotation driving means 31 is configured to rotate around the optical axis at the same angular velocity.

  The outputs of the image sensors 7r, 7g, and 7b are connected to the image boards 21r, 21g, and 21b via the signal amplifier circuits 8r, 8g, and 8b. The image boards 21r, 21g, and 21b are composed of A / D converters 22r, 22g, and 22b for red, green, and blue signals, and memories 23r, 23g, and 23b. The outputs of the image boards 21r, 21g, and 21b are image control means. 24.

  The image control unit 24 is connected to the control unit 25, the image recording unit 26, the television monitor 27, and the liquid crystal display unit 16. The image recording means 26 is a drive device that performs writing to or reading from a non-volatile recording medium D such as MO, MD, DVD-RAM, VTR tape, and hard disk.

  The control means 25 is connected to the photographing light source 13 via the photographing switch 29 and the strobe light emission control circuit 30. In the control means 25, a memory 25a and a strobe light emission control circuit 30 are provided with a first capacitor 30a, a second capacitor 30b, and a third capacitor 30c for controlling the amount of emitted light.

  When photographing the fundus using this fundus camera, first, the eye E and the fundus camera are aligned while observing the fundus Er of the eye E with infrared light. In this observation state, the infrared light cut filter 10 is detached from the optical path. In this state, the corneal stop 9, the lens stop 12, and the pupil stop 13 are rotationally controlled at a speed of about 5 rotations per second around the optical axis while substantially matching the light shielding meridians.

  Infrared light emitted from the observation light source 16 is collected by the condenser lens 15, passes through the apertures of the imaging light source 14, the rotating diaphragm 13, and the diaphragm 12, passes through the lens 10, and the rotating corneal diaphragm 9. It passes through the opening and is reflected to the left by the mirror around the perforated mirror 2 and illuminates the fundus Er through the objective lens 1 and the pupil Ep.

  Thus, the image of the fundus Er illuminated with infrared light passes through the objective lens 1, the photographing aperture 3, the focus lens 4, and the photographing lens 5 again and enters the color separation prism 6. The color separation prism 6 guides infrared light and red light to the image pickup device 7r, blue light to the image pickup device 7b, and green light to the image pickup device 7g. However, since the observation light is infrared light, it is connected to the image pickup device 7r. Image and converted into an electrical signal.

  FIG. 3 is a diagram illustrating a state in which the fundus is illuminated when the main meridian direction of the light-shielding region of the diaphragm is in the vertical direction.

  As shown by 301 and 302, there are portions where the illumination light does not reach to the left and right, but the vertical direction is well illuminated to the periphery. As shown in FIG. 4, the region where the light does not reach rotates with the rotation of the diaphragm in the main meridian direction.

  FIG. 5 is a fundus image reflected on the image sensor. As described above, flare and ghost images 501 and 502 generated in the crystalline lens and cornea of the eye to be examined are reflected in addition to the darkly illuminated portion. As shown in FIG. 6, these images also rotate in conjunction with the rotation of the stop in the main meridian direction.

  This fundus image is amplified at a predetermined amplification rate for observation through the signal amplifying means 8r, input to the image control means 24, and converted into digital data. The image control means 24 takes out only the data of the portion where the illumination is substantially uniform and has no flare or ghost light as shown by 503 in FIG. 5 from the image data, and converts the data other than the portion of 503 into a black image, As shown in FIG. Since the portion with good image quality is determined in advance corresponding to the rotation angle of the diaphragm, it can be easily converted by creating a table in which addresses for extracting images are determined corresponding to the angle of the diaphragm. This image is updated every 1/30 seconds, and all parts are displayed in six images. That is, since all the parts are displayed every 1/5 second, the photographer can observe the entire region of the fundus in almost real time, and can confirm the photographing part, the focus, and the like.

  The photographer who observes this image and confirms that the preparation for photographing is ready operates the photographing switch 29.

  The control means 25 detecting the input from the photographing switch 29 inserts the infrared light cut filter 11 into the optical path, and discharges the electric charge of the capacitor 30 a by the strobe light emission control circuit 30 to emit the photographing light source 14. The light emitted from the imaging light source 14 passes through the apertures of the diaphragm 13 and the diaphragm 12, and only visible light is transmitted by the infrared light cut filter 11, passes through the relay lens 10 and the aperture of the diaphragm 9, and the perforated mirror 2. Is reflected to the left by the mirror part around the lens and illuminates the fundus Er through the objective lens 1 and the pupil Ep.

  The image of the fundus Er illuminated in this way again passes through the objective lens 1, the photographing aperture 3, the focus lens 4 and the photographing lens 5, enters the color separation prism 6 and is separated into the respective colors, and the image pickup devices 7r, 7g, 7b is imaged and converted into an electrical signal. This signal is amplified at a predetermined amplification rate through the signal amplifying means 8r, 8g, and 8b, converted into digital image data by the A / D converters 22r, 22g, and 22b, input to the image control means 24, and input to the image. It is recorded in the memory 24a together with angle information in the main meridian direction of the rotary diaphragm.

  The control means 25 that has detected the recording completion signal emits the strobe light source 14 again by the electric charge accumulated in the second capacitor 31b in synchronization with the timing at which the main meridian service of the aperture is rotated by 30 ° from the time of the photographing. At the same time, charging of the first capacitor 31a is started. The light emitted from the strobe light source 14 illuminates the fundus Er to be examined in the same manner as described above. However, as described above, since the light-shielding portion of the diaphragm continues to rotate, the illumination area of the fundus also changes in conjunction with the angle. ing.

  The fundus image illuminated in this way is incident on the color separation prism 6 to be separated into each color as described above, is imaged on the image sensors 7r, 7g, and 7b, and is converted into an electrical signal. This signal is amplified at a predetermined amplification rate through the signal amplifying means 20r, 20g, 20b, converted into digital image data by the A / D converters 22r, 22g, 22b, and input to the image control means 24. It is stored in the image memory 24a together with the rotation angle of the diaphragm. The control means 25 that has detected the recording completion signal then emits the strobe light source 13 with the electric charge accumulated in the third capacitor 31c and starts charging the second capacitor 31b.

  As described above, the fundus is illuminated with light emitted from the light source 13, and the fundus image is formed on the image pickup devices 7r, 7g, and 7b and converted into an electric signal. This signal is amplified by a predetermined amplification rate through the signal amplification means 20r, 20g, 20b, converted into digital image data by the A / D conversion sections 22r, 22g, 22b, and input to the image control means 24. It is stored in the image memory 24a together with the rotation angle of the diaphragm.

  In this way, the control means sequentially emits the strobe light source 13 and reads out the image from the image sensor in synchronization with the rotation angle of the diaphragm, and stores six images with different main meridian directions of the diaphragm. Record in 24a. In the six images, as shown in FIG. 9, a good image portion rotates with the meridian direction. The image control means 24 extracts a good portion of the images shown in 901, 902, 903, 904, 905, and 906 in FIG. 9 from these six images, and displays one image as shown in FIG. 9 (F). The fundus image is synthesized, the synthesized fundus image is recorded on the recording medium D by the recording means 26, and is further displayed on the monitor 27 to complete the photographing.

  As shown in the figure, the good portion of the image shown in FIG. 9 is determined by the rotation angle of the diaphragm at the time of shooting. Therefore, the portion extracted from each image can be easily created by creating a table of image addresses in advance. You can choose.

  FIG. 10 shows the relationship between the aperture image and the imaging aperture on the eye pupil to be examined.

  101 is the iris of the eye to be examined, and the inside is the eye pupil to be examined. The light shielding area of the stop is projected into the pupil as indicated at 102. Accordingly, since light cannot pass through this portion, the fundus is illuminated from the left and right portions as indicated at 103. The photographing aperture is arranged at the center of the pupil as indicated by 104. As a result, the fundus can be illuminated using the inner part, compared to the case of illuminating through a ring-shaped stop having a conventional round light-shielding region, so that a good image can be obtained even for a subject having a small pupil diameter. Can be obtained.

  In order to prevent flare and ghost from entering the image in all meridian directions, the light shielding region of the diaphragm must be formed in a constant size, that is, circular in all meridian directions. However, if the aperture is smaller than the size of the stop, it becomes difficult to illuminate and photography cannot be performed. As shown in the above embodiment, by making the size of the light-shielding region different between the main meridian direction and the direction perpendicular thereto, it is possible to restrict the range where the flare occurs and to secure a good portion of the image. Therefore, by extracting a good portion, it is possible to photograph a subject having a small pupil diameter.

  In the above embodiment, the strobe light source continuously emits light, but a discharge tube that emits light continuously may be used.

  In the above embodiment, a still image is photographed by continuously rotating a diaphragm having a light-shielding area in the meridian direction. However, a wider image area is effective when the rotation is stopped at the moment of flash emission. This improves the shooting efficiency.

  By configuring the diaphragm with a liquid crystal display element, the movable portion can be eliminated and the structure can be simplified.

  The present invention can be applied to an ophthalmologic photographing apparatus used in an ophthalmic clinic or the like.

It is a block diagram of the fundus camera of Embodiment 1 of the present invention. It is a figure which shows the aperture_diaphragm | restriction which has a light-shielding area | region in the meridian direction. It is a figure which shows a mode that a fundus is illuminated. It is a figure which shows a mode that a fundus is illuminated. It is a figure which shows the fundus image reflected on an imaging means. It is a figure which shows the fundus image reflected on an imaging means. It is a figure which shows the fundus image reflected on a monitor. It is a figure which shows the fundus image reflected on a monitor. It is a figure which shows the fundus image recorded on the memory. It is a figure which shows the positional relationship of a to-be-tested eye pupil and an aperture_diaphragm | restriction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Objective lens 2 Perforated mirror 3 Imaging aperture 4 Focus lens 5 Imaging lens 6 Color splitting prism 7 Imaging element 8 Amplifying circuit 9 Corneal aperture 10 Lens 11 Infrared light cut filter 12 Lens aperture 13 Pupil aperture 14 Imaging light source 15 Lens 16 Observation Light source 21 Image board 22 A / D converter 23 Memory 24 Image control means 25 Control means 26 Image recording means 27 Television monitor 29 Shooting switch 30 Strobe light emission control circuit

Claims (2)

  Illuminates the fundus of the eye to be examined through a light shielding means that has a light shielding area with different lengths in the main meridian direction and the vertical direction arranged in the vicinity of the anterior eye portion of the eye to be examined, and is arranged to be rotatable around the optical axis. Fundus illuminating means, photographing means for photographing a fundus image corresponding to different rotation angles of the light shielding means, and obtaining a plurality of images, and image synthesizing means for creating one image from the plurality of images. A characteristic ophthalmologic photographing apparatus.   It has a common principal meridian direction arranged near the anterior segment of the eye to be examined, has a light shielding region with different lengths in the principal meridian direction and its vertical direction, and rotates at the same rotational speed around the optical axis A plurality of images obtained by photographing a fundus image corresponding to different rotation angles of the fundus illuminating means that illuminates the fundus oculi to be examined through these diaphragms An ophthalmologic photographing apparatus comprising photographing means for obtaining an image, and image composition means for creating one image from the plurality of images.

Images