JPH08117192A - Ophthalmologic photographing apparatus - Google Patents

Abstract

PURPOSE: To provide an ophthalmologic photographing apparatus capable of maintaining the brightness of video images at adequate brightness without the need for adjusting the brightness of a light source for illumination by a manual operation and without acting an AGC of a video camera. CONSTITUTION: This ophthalmologic photographing apparatus has an optical system 10 for illumination which illuminates the eye to be examined and an optical system 40 for photographing having a video camera 49 for picking up the image of the eye E to be examined and to be illuminated by this optical system for illumination. The apparatus is provided with a small-diameter light shielding plate 16, a photographing diaphragm 24, etc., for controlling the light quantity arriving at the image pickup element 49a of the video camera 49 for adequately maintaining the brightness of the video image picked up by the video camera 49 in accordance with this luminance value.

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 having an illumination optical system for illuminating an eye to be examined and a photographing optical system having a video camera for photographing the eye to be examined illuminated by the illumination optical system. .

[0002]

2. Description of the Related Art A fundus camera, which is one of the ophthalmic photographing apparatuses, sometimes photographs the fundus by fluorescence, but it is necessary to continuously photograph the fundus in a short time in the initial stage when the fluorescence that appears on the fundus changes rapidly. For this reason, a video camera is provided for shooting.

In such a fundus camera, an operator manually adjusts the brightness of the illumination light source while watching the image displayed on the monitor in order to make the brightness of the captured video image appropriate. , AGC (auto gain control) of the video camera is working.

[0004]

However, in the initial stage of fluorescence photography, fluorescence rapidly appears on the fundus, so that the luminance of the fundus rapidly increases. Therefore, it is difficult to manually adjust the brightness of the illumination light source while watching the image on the monitor, and the operation is troublesome. Further, there is a limit in making the brightness of the video image proper with the AGC of the video camera, and there is a problem that the image becomes rough.

The present invention has been made in view of the above problems, and an object thereof is to eliminate the need to manually adjust the brightness of an illumination light source and to display a video image without operating the AGC of the video camera. An object of the present invention is to provide an ophthalmologic photographing apparatus capable of adjusting brightness appropriately.

[0006]

In order to achieve the above object, the invention of claim 1 has an illumination optical system for illuminating an eye to be inspected and a video camera for taking an image of the eye to be inspected illuminated by the illumination optical system. In an ophthalmologic imaging device having an imaging optical system, a brightness value of an eye image to be inspected is obtained from a video signal output from the video camera, and based on this brightness value, the brightness of a video image captured by the video camera is determined. It is characterized in that a light amount control means for controlling the amount of light reaching the image pickup device of the video camera is provided in order to keep it properly.

According to a second aspect of the present invention, there is provided an ophthalmologic photographing apparatus comprising: an illumination optical system for illuminating an eye to be examined; and a photographing optical system having a video camera for photographing the eye to be examined illuminated by the illumination optical system. Based on a light receiving sensor that receives a part of the reflected light reflected from the eye to be inspected and the amount of light received by the light receiving sensor, the video for properly maintaining the brightness of the video image captured by the video camera Light quantity control means for controlling the quantity of light reaching the image pickup device of the camera is provided.

[0008]

According to the present invention, the light amount control means obtains the brightness value of the eye image from the video signal output from the video camera, and controls the light amount reaching the image pickup device of the video camera based on the brightness value. To do.

According to the second aspect of the present invention, the light receiving sensor receives a part of the reflected light reflected from the eye to be inspected, and the light amount control means determines the image receiving element of the video camera based on the light receiving amount received by the light receiving sensor. Control the amount of light reaching.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fundus camera, which is one of the ophthalmologic photographing apparatuses according to the present invention, will be described below with reference to the drawings.

In FIG. 1, 10 is an illumination optical system of the fundus camera, and 40 is an observation / photographing optical system of the fundus camera.

[Illumination Optical System 10] The illumination optical system 10 includes an observation light source (for example, a halogen lamp) 11, a condenser lens 12, a photographing light source (for example, a xenon lamp) 31,
Exciter filters 32 and 32 'for fluorescence photography that can be inserted into and removed from the illumination optical path indicated by the optical axis O1, the condenser lens 13,
Small-diameter light-shielding plate 14, ring-shaped diaphragm 15, small-diameter light-shielding plate 16,
Relay lens 17, reflection mirror 18, relay lens 1
9, black dot plate 20, relay lens 21, perforated mirror 2
2. The objective lens 23.

A plurality of small-diameter light-shielding plates 16 are provided on a transparent circular rotary plate 70, as shown in FIG. 2, for example, and a plurality of them are prepared. The small-diameter light-shielding plates 16a to 16d have different diameters, and the rotary plate 70 is rotated by a motor (not shown) so that the centers of the small-diameter light-shielding plates 16a to 16d are aligned with the optical axis O1 and are inserted into the optical path 10a. It has become. Then, the small-diameter light-shielding plates 16a to 16d constitute a light amount control means (light control member).

The illumination light for observation from the observation light source 11 is
It is projected onto the fundus EF through each optical component from the condenser lens 12 to the objective lens 23. Moreover, the illumination light for photography from the photography light source 31 is projected on the fundus EF through each optical component from the condenser lens 13 to the objective lens 23.

The small-diameter light-shielding plate 14 is conjugated with the cornea EC,
The ring-shaped diaphragm 15 is conjugated with the pupil EP, and the small-diameter light-shielding plate 16 is conjugated with the rear surface of the lens EL. Also, the black dot plate 2
0 indicates that the light reflected on the surface of the objective lens 23 is a perforated mirror 2
This is to prevent the second hole 22a from passing through.

An exciter filter 32 for visible fluorescence, which transmits part of visible light and blocks other light, is inserted in the optical path during visible fluorescence photography, and part of infrared light is transmitted during infrared fluorescence photography. And an infrared fluorescent exciter filter 32 'for blocking other light is inserted in the optical path.

[Observation / photographing optical system 40] The observation / photographing optical system 40 includes an objective lens 23 facing the eye E to be inspected, a hole portion 22a of a perforated mirror 22, a photographing diaphragm (a light control member, an aperture diaphragm) 2
4, barrier filters 41, 41 'that can be inserted into and removed from the observation / photographing optical path indicated by the optical axis O2 in FIG. 1, a focusing lens 42, an imaging lens 43, a reflection mirror 44, a mask 45, a field lens 46, a reflection mirror 47. , A relay lens 48, and a television camera (video camera) 49. On the extension of the optical axis 02 on the right side of the reflection mirror 44, an optical system for observing the naked eye, a 35 mm camera, etc. are usually arranged, but they are omitted for simplification of description. The reflecting mirror 44 is designed to jump up when observing with the naked eye or when photographing with a 35 mm camera.

The visible fluorescence barrier filter 41 transmits a part of visible light and blocks other light, and is inserted into the optical path at the time of visible fluorescence photographing. The infrared fluorescence barrier filter 41 'transmits a part of infrared light and blocks other light, and is inserted in the optical path at the time of infrared fluorescence photography.

As shown in FIG. 3, for example, the photographic diaphragm 24 is formed by providing a plurality of apertures 24a to 24d on a circular rotary plate 80 that shields light, and the apertures 24a to 24d have different diameters. The rotary plate 80 is rotated by a motor (not shown) so that the centers of the openings 24a to 24d are aligned with the optical axis and inserted into the optical path 40a. Further, the photographing diaphragm 24 may be a diaphragm such as a shutter diaphragm whose diameter can be continuously changed. Then, the photographic diaphragm 24 functions as a light amount control means for controlling the light amount.

The image formed by the reflected light from the fundus EF is formed by the objective lens 23, the hole 22a of the perforated mirror 22, and the photographing diaphragm 2.
4, through a focusing lens 42, an image forming lens 43, a reflection mirror 44, a mask 45, a field lens 46, a reflection mirror 47, and a relay lens 48, and an image is formed on a CCD 49a which is an image pickup device of the television camera 49. . CC
The video signal of the image formed on D49a is input to the display unit 61 such as a monitor via the control unit 60, and the fundus image F is displayed on the display unit 61 in real time.

[Control Unit] As shown in FIG. 4, the control unit 60 includes an arithmetic control circuit 62, a motor drive circuit 63 for driving a motor (not shown) for rotating the rotary plate 70, and a rotary plate 80. Motor drive circuit 64 that drives a motor (not shown) that rotates, solenoid drive circuit 65 that drives a solenoid (not shown) that inserts exciter filters 32 and 32 ', and insertion of barrier filters 41 and 41' Solenoid drive circuit 66 for driving a solenoid (not shown) for performing the above, and light emitting circuit 67 for lighting the observation light source 11
And a light emitting circuit 68 for causing the photographing light source 31 to emit light, a recording device 81 for recording a fundus image and the like, a focusing drive unit (not shown) for moving the focusing lens 42, and the like.

The arithmetic control circuit 62 has motor drive circuits 63, 64 and solenoid drive circuits 65, 64 depending on various conditions (for example, focusing operation and photographing operation) by the operation of the operation unit 69.
A drive signal is output to 66 and a light emission signal is output to the light emitting circuits 67 and 68. Further, the arithmetic control circuit 62 includes the CCD 49
Obtain the luminance value of the fundus image from the video signal output from a,
This brightness value is compared with a preset reference value, and the motor drive circuits 63 and 64 are controlled so that the fundus image can be imaged with appropriate brightness based on the result of this comparison, and the small-diameter light-shielding plates 16a to 16d and The openings 24a to 24d of the photographing diaphragm 24 are switched.

The brightness value is obtained as the sum or average of the brightness values of all pixels of the fundus image, or the fundus image is divided into a plurality of areas (for example, 16 areas), and the brightness value is the highest in each area. It is calculated as the sum or average of all the pixels of the portion or the portion having the lowest luminance value or both of them. Alternatively, it is calculated from the sum of the brightness values of the upper pixels among the brightness values of all the pixels of the fundus image, or the highest brightness value.

The arithmetic control circuit 62 is a CCD 49a.
Control is performed to record the fundus image imaged in the recording device 81 or to display the fundus image recorded in the recording device 81 on the display unit 61.

[Visible Imaging] When the power of the fundus camera body (both not shown) is turned on, the arithmetic control circuit 62 first activates the light emitting circuit 67 to turn on the observation light source 11. From this state, focusing work including alignment with respect to the fundus EF is performed, and when this focusing work is completed, the illumination light from the observation light source 11 is projected onto the fundus EF via each optical component of the observation illumination optical system 10. Be reflected and reflected.

On the other hand, the reflected light from the fundus EF is composed of optical components from the objective lens 23 to the imaging lens 43 of the observation / photographing optical system 40, the reflection mirror 44, the mask 45, the field lens 46, the reflection mirror 47, and the relay lens. It is guided to the CCD 49a of the television camera 49 via 48 and the like, whereby the fundus image F is formed on the CCD 49a, and the fundus image F is formed.
Is displayed on the display means 61.

The arithmetic control circuit 62 calculates the luminance value of the fundus image based on the video signal output from the CCD 49a,
This brightness value is compared with a preset reference value, and when the brightness value is lower than the reference value, the motor drive circuit 63 is driven to insert the small-diameter light-shielding plate 16 having a smaller diameter into the optical path.
Further, the motor drive circuit 64 is driven to switch to the openings 24a to 24d of the photographing aperture 24 having a larger diameter, and the CCD
It controls the amount of light reaching 49a.

As a result, the amount of illumination light projected on the fundus EF increases, and the amount of light passing through the photographing diaphragm 24 increases, so that the fundus image can be imaged with appropriate brightness. That is, the video image can be made to have an appropriate brightness. By performing this control for each field, each frame, or every few fields, every few frames, it is possible to always capture the fundus image with appropriate brightness.

As described above, the arithmetic control circuit 62 calculates the luminance value of the fundus image, and drives the motor drive circuits 63 and 64 based on the luminance value so that the small-diameter light-shielding plate with which the video image has an appropriate brightness. 16, apertures 24b to 24 of the photographing diaphragm 24
Since d is inserted in the optical path, there is no need to manually adjust the brightness of the illumination light source as before, and the brightness of the video image should be optimized without using the AGC of the video camera. You can

[Fluorescence photography] When performing visible / infrared fluorescence photography of the fundus EF, fluorescein sodium (when visible fluorescence photography) or indocyanine green (when infrared fluorescence photography) is injected intravenously while Insert the exciter filter 32 and the visible fluorescent barrier filter 41 (when the visible fluorescent image is taken), or the infrared exciter filter 32 'and the infrared fluorescent barrier filter 41' (when the infrared fluorescent image is taken) into each optical path. To do. In this insertion, when the visible fluorescence mode and the infrared fluorescence mode are set by the mode setting switch (not shown), the arithmetic control circuit 62 causes the solenoid drive circuit 6 to operate.
It is performed by driving 5,66.

When the exciter filters 32 and 32 'are inserted, the excitation light is projected onto the fundus of the eye, and when the fluorescent agent appears in the blood vessels of the fundus, the excitation light emits visible fluorescence or infrared fluorescence. It reaches the CCD 49a of the television camera 49 via the photographing optical system 40, and a fluorescent image is formed on the CCD 49a. The fluorescent image is displayed on the display unit 61.
Is displayed in.

The arithmetic control circuit 62, as described above,
The brightness value of the fundus image is calculated based on the image signal output from D49a, and the small-diameter light-shielding plate 16 and the openings 24a to 24d of the photographing diaphragm 24 are inserted into the optical path based on this brightness value. Here, since the brightness of the fluorescent image is considerably low at the stage when the fluorescent agent begins to appear, the small-diameter light-shielding plate 16 having the smallest diameter and the aperture 24c or 24d of the photographing diaphragm having the large diameter are inserted in the optical path.

As a result, the amount of excitation light projected on the fundus EF increases and the amount of fluorescence passing through the photographing diaphragm 24 increases, so that a relatively bright fundus fluorescence image can be captured even in this initial stage.

After this initial stage, the fluorescent agent appearing on the fundus sharply increases, the fundus fluorescent image sharply becomes bright, and the brightness value of the fundus fluorescent image rapidly increases. Since the arithmetic control circuit 62 switches the small-diameter light-shielding plate 16 and the openings 24a to 24d of the photographing diaphragm 24,
The video image can be made to have proper brightness. Therefore, even if the brightness value of the fluorescent image changes greatly in a short time, it is possible to always obtain a video image with appropriate brightness.

The arithmetic control circuit 62 calculates the luminance value of the fundus fluorescence image, and based on this luminance value, the motor drive circuit 63,
By driving 64, the small-diameter light-shielding plate 16 and the apertures 24a to 24d of the photographing diaphragm 24, which make the fundus fluorescent image have appropriate brightness, are inserted in the optical path, so that it is not necessary to manually adjust the brightness of the illumination light source. Moreover, the brightness of the video image can be made appropriate without operating the AGC of the video camera.

In this embodiment, in addition to switching the diameter of the small-diameter light-shielding plate 16 in both visible and fluorescent photographing, the photographing diaphragm 2 is used.
Since the four apertures 24a to 24d are also switched, the amount of reflected light from the fundus can be finely adjusted, and as a result, a fundus fluorescence image with appropriate brightness can be taken at all times. That is, the brightness of the video image can be made appropriate.

By the way, when the diameter of the small-diameter light-shielding plate 16 is switched, the amount of illumination light projected on the fundus EF increases or decreases, so that there is a limit to the adjustment range from the viewpoint of safety (prevention of retinal light damage). Further, when the apertures 24a to 24d of the photographing diaphragm 24 are changed, the depth of focus and the resolution change. By adjusting both of these in consideration of these things, it is possible to safely and safely capture a fundus fluorescence image of good image quality with proper brightness.

FIG. 5 shows a second embodiment. In this embodiment, the small-diameter light-shielding plate 16 and the apertures 24a-2 of the photographing diaphragm 24 are based on the amount of light received by the light-receiving element 53.
4d is also switched. Reference numeral 51 is a beam splitter, and 52 is a condenser lens.

By arranging a plurality of small condenser lenses two-dimensionally instead of the condenser lens 52 and arranging the light receiving element at the focal position of each condenser lens, the fundus EF can be obtained as in the first embodiment. Of the small-diameter light-shielding plate 16 and the apertures 24a to 24d of the photographing diaphragm 24 on the basis of the amount of reflected light from a plurality of partial areas of
Can be controlled.

In each of the above embodiments, the small-diameter light shielding plate 1 is used.
Although the diameter of 6 is changed, the size of the small-diameter light shielding plate 14 or the ring-shaped diaphragm 15 may be changed.
Further, any two or three of them may be changed in size.

Alternatively, instead of the small-diameter light-shielding plate 16, a transmissive liquid crystal display may be arranged, and a black small-diameter plate may be displayed on the display portion of the liquid crystal display. In this case, the size of the displayed small diameter plate can be continuously changed.

Instead of changing the diameter of the small-diameter light-shielding plate 16, an ND filter is inserted at the position shown by the dotted line,
This may be carried out by changing the transmittance of the D filter, or as shown in FIG. 6, the dimming circuit (light quantity control means) 82 may be used to control the quantity of light emitted from the light sources 11, 31 by the light emitting circuits 67, 68. Good.

In each of the above embodiments, the CCD 4 is used.
The diameters of the small-diameter light shielding plate 16 and the photographing diaphragm 24 are changed based on the amount of light received by the light receiving element 9a and the amount of light received by the light-receiving element 53. The diameter may be changed to capture a fundus fluorescence image with appropriate brightness.

[0044]

According to the present invention, it is not necessary to manually adjust the brightness of the illumination light source, and moreover, the brightness of the video image can always be made appropriate without operating the AGC of the video camera. it can.

[Brief description of drawings]

FIG. 1 is an optical layout diagram showing an optical system of an embodiment of a fundus camera, which is one of the ophthalmologic photographing apparatuses according to the present invention.

FIG. 2 is a plan view showing the configuration of the small-diameter light-shielding plate shown in FIG.

FIG. 3 is a plan view showing a configuration of a photographing diaphragm shown in FIG.

FIG. 4 is a block diagram showing a configuration of a control system of the fundus camera.

FIG. 5 is an optical layout diagram showing a configuration of another embodiment.

FIG. 6 is a block diagram showing a configuration of a control system of a fundus camera of another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Illumination optical system 16 ... Small-diameter light-shielding plate (light quantity control means) 40 ... Photographing optical system 49 ... Video camera 49a ... Imaging device

Claims (7)

[Claims] 1. An ophthalmologic photographing apparatus comprising: an illumination optical system for illuminating an eye to be examined; and a photographing optical system having a video camera for photographing the eye to be examined illuminated by the illumination optical system. The brightness value of the image of the eye to be inspected is obtained from the video signal, and the amount of light reaching the image sensor of the video camera is controlled based on the brightness value in order to keep the brightness of the video image captured by the video camera appropriate. An ophthalmologic photographing apparatus comprising a light amount control means. 2. An ophthalmic photographing apparatus comprising: an illumination optical system for illuminating an eye to be examined; and a photographing optical system having a video camera for photographing the eye to be examined illuminated by the illumination optical system. A light receiving sensor for receiving a part of the reflected light, and an image sensor of the video camera for properly maintaining the brightness of the video image captured by the video camera based on the amount of light received by the light receiving sensor. An ophthalmologic imaging apparatus comprising: a light amount control unit that controls the amount of light that reaches. 3. The light amount control means is disposed in at least one of the illumination optical system and the photographing optical system, and adjusts the light amount of a light beam passing through the optical path of the illumination optical system or the photographing optical system. The ophthalmologic imaging apparatus according to claim 1, wherein the ophthalmologic imaging apparatus is configured by a member. 4. The ophthalmologic photographing apparatus according to claim 3, wherein the light control member is composed of a light shielding plate whose diameter is adjustable. 5. The ophthalmologic photographing apparatus according to claim 3, wherein the light control member is composed of an aperture stop whose aperture size is adjustable. 6. The light control member is an ND with adjustable transmittance.
A filter comprising a filter.
Ophthalmic imaging device. 7. The ophthalmologic photographing apparatus according to claim 1, wherein the light amount control means is composed of an adjusting circuit for adjusting a light emitting amount of a light source of the illumination optical system.