JPH09131321A - Fundoscopy device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform photographing with a proper amount of exposure, according to a photographing mode. SOLUTION: In the case of photographing in color, an exciter filter 6 and a barrier filter 9 are retreated from a light path 9, and the dynamic image of an eyeground Er is displayed in the window on a television monitor 23 by an observation alignment light source 1, and alignment is performed, and the color static image of the eyeground Er is photographed by a stroboscopic light source 4. At this time, a luminous quantity sensor 15 receives a part of a luminous flux, and a control means 16 compares it with the reference value for photographing in color, and when it gets over the reference value, a power controller 20 stops the light emission of the stroboscopic light source 4. On the other hand, in the case of photographing with infrared fluorescent ray, an exciter filter 6 is inserted into a light path 6, and in the same way as mentioned above, the dynamic image of the eyeground Er by excitation light is displayed in the window on the television monitor 23, and alignment is performed. A fluorescent agent is injected intravenously into a person to be examined, and a barrier filter 9 is inserted into the light path, and a stroboscopic beam 4 is applied, and the image of the fluorescent light from eyeground Er is picked up on a camera 13, thus the monochromatic static image of the infrared fluorescent light is photographed. In the same way as mentioned above, a luminous quantity sensor 15 receives a part of the luminous flux, and compares it with the reference value for fluorescent photographing and stops the light emission of the stroboscopic light source 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus examination apparatus used when examining a subject's fundus in an ophthalmology clinic.

[0002]

2. Description of the Related Art Conventionally, in a fundus camera, the amount of light reflected from an image pickup medium is detected, and when the amount of exposure reaches a reference value, the strobe emission is stopped to automatically adjust the amount of exposure. It has been known. in recent years,
In addition to color photography and visible fluorescence photography, infrared fluorescence photography that uses infrared light has come to be performed. In particular, in this infrared fluorescence photography, the fluorescence intensity changes rapidly with the appearance of fluorescence, so the exposure Is required to be automatically adjusted.

[0003]

However, in the conventional fundus camera, the color image appears on the entire surface of the screen, but the fluorescent image is displayed by a thin bright line in the black background, so that the surface of the imaging medium is properly exposed. There is a considerable difference between the two in the total light amount reaching. Therefore, if the automatic light adjustment of fluorescence photography is performed with the same reference light amount as in color photography, there is a problem that the image is too bright. Further, when an image is captured using an electronic imaging medium, the signal is A / D converted, and the image data is treated as digital data, the resolution in the density direction is limited. Otherwise, there is a drawback that information in the density direction is lost.

The object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a fundus examination device capable of always taking an image with an appropriate exposure amount according to an image taking mode.

[0005]

A fundus examination apparatus according to the present application for achieving the above object is a fundus illuminating means having a strobe light source and a removable first band pass filter, and a removable fundus illuminating means. A fundus imaging means having a band pass filter, a photographing light amount detecting means for receiving a part of reflected light from the fundus, and a received light amount of the photographing light amount detecting means by the strobe light source having reached a reference value. A light emission control means for detecting and controlling the light emission of the strobe light source, and the light emission control means changes the reference value of the received light amount according to the insertion and removal of the first and / or second bandpass filter. It is characterized by

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 is a block diagram of the fundus camera of the embodiment, in which a condenser lens 3, a still image capturing light source 4 such as a strobe, and a ring-shaped aperture are provided on the optical path from the observation alignment light source 1 such as a lamp to the objective lens 2. The stop 5 having the exciter filter 6, which can be inserted into and removed from the optical path, the relay lens 7, and the perforated mirror 8 are sequentially arranged. On the optical path behind the perforated mirror 8, a barrier filter 9 which can be inserted into and removed from the optical path, a photographing lens 10, a switching mirror 11, and a high-definition camera 12 for color still image shooting or monochrome still image shooting are sequentially arranged. A high-sensitivity camera 13 for observing a moving image is arranged in the reflection direction of the switching mirror 11. The lens 14 and the light amount sensor 15 are arranged below the front surface of the high-definition camera 12, and an exposure amount detecting means for receiving a part of the reflected light from the imaging surface of the high-definition camera 12 is formed.

Further, there is provided a control means 16 having an arithmetic means, a storage means, an input / output means for digital signals and video signals, and the like, and the control means 16 has a high-definition camera 12,
The outputs of the high-sensitivity camera 13, the light amount sensor 15, the sensitivity selection switch 17, the photographing switch 18, and the mode selection switch 19 are connected, and the output of the control means 16 is a power supply controller 2 having a charge storage means such as a capacitor.
It is connected to the still image capturing power source 4 via 0, and is also connected to the image storage means 21 such as a hard disk and the television monitor 23 having the mouse 22. It should be noted that on the television monitor 23, a window in which the display position and display magnification can be freely changed and deleted by the mouse 22 can be displayed. Further, the photographing switch 18 comprises a two-stage switch, and the barrier filter 9 is inserted in the optical path by operating the first stage switch in the fluorescence mode.

In the case of color photographing, a high-definition camera 12 having a color filter in front of an image sensor is used as the high-definition camera 12, and a photographing mode selection switch 19 is used.
Selects color photography and retracts the exciter filter 6 and the barrier filter 9 for fluorescence photography out of the optical path. Then, the ISO sensitivity of the film in the high-definition camera 12 is set by the sensitivity selection switch 17.

The light beam emitted from the observation alignment light source 1 passes through the condenser lens 3, the strobe light source 4, the diaphragm 5, and the relay lens 7, is reflected to the left by the mirror portion of the perforated mirror 8, and passes through the objective lens 2. , Pupil of eye E
The fundus Er is illuminated via Ep. The reflected light from the fundus Er passes from the pupil Ep through the objective lens 2, the hole portion of the perforated mirror 8 and the taking lens 10, and is imaged on the image pickup surface of the high-sensitivity camera 13 for moving image observation by the switching mirror 11. It is converted into an electric signal and input to the control means 16. Then, this moving image is displayed on the TV monitor 23 in one of the windows whose position and size are selected by the mouse 22.

The examiner looks at the fundus image of the subject's eye E reflected in this window, confirms that the imaged region, alignment, and focus state are good, and then operates the image pickup switch 18. As a result, the switching mirror 11 is retracted out of the optical path, the power supply controller 20 starts discharging, and the strobe light source 4 emits light. The light flux emitted from the strobe light source 4 illuminates the fundus Er through the same optical path as the light flux emitted from the observation alignment light source 1. Reflected light from the fundus Er also forms a fundus image on the imaging surface of the high-definition camera 12 for still image shooting through the same optical path.

At this time, a part of the light beam is reflected by the image pickup surface, passes through the lens 14 and is incident on the light amount sensor 15 to be photoelectrically converted. This signal is input to the control means 16 and integrated, and its value is compared with a reference value. The integrated value increases with time, and when the value exceeds the reference value, a light emission stop signal is output, the power supply controller 20 stops discharge, and the strobe light source 4 stops light emission.

This reference value is stored in advance in the memory in the control means 16 for each film ISO sensitivity of the camera to be set, and is read and used according to the ISO sensitivity setting of the film to be used. Therefore, since an appropriate reference value is automatically set in accordance with the photographing sensitivity selected by the photographer according to the purpose, it is possible to always obtain an image with an appropriate exposure amount.

The image picked up by the high-definition camera 12 is converted into an electric signal, then converted into a digital signal, transferred to the memory in the control means 16, stored in the image storage means 18, and stored in the television monitor 23. Displayed in one of the windows. In this way, the predetermined region on the fundus Er is photographed and the color photographing is completed.

In the case of performing infrared fluorescence photography, if the high-definition camera 12 is replaced with that for monochrome photography having sensitivity to infrared light, and the ICG photography mode is selected by the photography mode selection switch 19, the ICG photography is performed. The exciter filter 6 is inserted in the optical path. Then, the examiner selects the ISO sensitivity of the film of the high-definition camera 12 with the sensitivity selection switch 17 according to the amount of the fluorescent drug, the intravenous injection speed, and the like.

When the observation alignment light source 1 is turned on,
The light flux passes through the condenser lens 3, the strobe light source 4, the diaphragm 5, the exciter filter 6, and the relay lens 7, is reflected to the left by the mirror portion of the perforated mirror 8, passes through the objective lens 2, and the pupil Ep of the eye E to be examined. To illuminate the fundus Er. The reflected light from the fundus Er is transmitted from the pupil Ep to the objective lens 2,
An image is formed on the image pickup surface of the high-sensitivity camera 13 by the switching mirror 11, passing through the hole of the perforated mirror 8 and the taking lens 10, converted into an electric signal, and input to the control means 16.

This moving image is displayed on one of the windows whose position and size are selected by the mouse 22 on the television monitor 23, and the examiner views the fundus of the eye E to be examined illuminated by the excitation light reflected in this window. After checking the imaged part, alignment, and focus state by observing the image and confirming that these are good, a fluorescent agent is intravenously injected to the subject, and at the same time, the first step of the imaging switch 18 is turned on. Press to insert the vialia filter 9 into the optical path. After that, the appearance of the fluorescent image is confirmed on the observation screen of the window on the television monitor 22, and the second stage of the photographing switch 18 is pressed.

As a result, the switching mirror 11 is retracted out of the optical path, and at the same time, the power supply controller 20 starts discharging and the strobe light source 4 emits light. The light flux emitted from the strobe light source 4 illuminates the fundus Er of the eye E through the same optical path as the light flux from the observation alignment light source 1. At this time, the fundus Er illuminated by the excitation light emits fluorescence, and the fluorescence passes from the pupil Ep through the objective lens 2, the hole portion of the perforated mirror 8, the barrier filter 9, and the photographing lens 10 to the high-definition camera 1.
An image is formed on the image pickup surface of 2.

At this time, a part of the light beam reflected by the image pickup surface passes through the lens 14 and enters the light amount sensor 15, is photoelectrically converted, is input to the control means 16, and is integrated. The integrated value is compared with the reference value, and when the value exceeds the reference value, a light emission stop signal is output, the power supply controller 20 stops the discharge, and the strobe light source 4 stops the light emission. This reference value is stored in advance in the memory of the control means 16 in correspondence with the film sensitivity and shooting mode of the camera to be set, and is read and used according to the film sensitivity setting and shooting mode. In this way, since the appropriate reference value is automatically set according to the photographing sensitivity selected by the examiner according to the purpose, it is possible to always obtain a photograph with an appropriate exposure amount.

FIG. 2 shows the color fundus image Er ', and FIG. 3 shows the density distribution on the line segment A. In a color image, since the light flux is reflected from the entire fundus Er, the entire image has density and is appropriate. In order to perform the exposure, it is necessary to control the light emission time of the strobe light source 4 so that both the bright portion in the central portion and the dark portion in the peripheral portion of the image are within the allowable value. Since the light amount sensor 15 detects the amount of reflected light from the entire image, it is necessary to set a reference value such that the entire image can be detected at an appropriate density as shown in FIG.

On the other hand, FIG. 4 shows the fluorescent fundus image Er ″, and FIG. 5 shows the concentration distribution on the line segment A. Since the fluorescent image receives only the fluorescent light from the blood vessel and a part of the fluorescent light leak site, The image of the part is not detected and is completely dark.Therefore, in order to perform the proper exposure in this case, the strobe light source 4 is controlled so that both the fluorescence from the blood vessel and the weak fluorescence from the leaked portion are within the allowable value. The emission time must be controlled, and for this reason the reference value for fluorescence must be smaller than the reference value for color.

Since the display screen can be set to an arbitrary position and size by performing display using the multi-window as described above, in order to observe the moving image for alignment and the still image for photographing. In addition, it is not necessary to provide separate TV monitors or switch the screens with one TV monitor, and it is possible to observe simultaneously on a single screen, and a large arrangement space is not required, and work efficiency is improved. Furthermore, by setting different reference values for each of the color photographing mode and the fluorescence photographing mode, it is possible to always photograph an image with an appropriate exposure amount, which is extremely effective for precise inspection diagnosis.

Further, if a color photographing camera and a fluorescence photographing camera are mounted in advance on the fundus camera and the photographing modes are automatically switched, the efficiency is further improved.

Further, in the case of fluorescence photography using infrared light, since the intensity of the fluorescence light amount changes greatly with time, it cannot be adjusted simply by changing the light emission amount of the strobe light source 4.
It is necessary to readjust the film sensitivity setting many times during shooting. Therefore, for example, when the exposure amount to the image pickup means does not reach the reference value even if all the energy stored in the condenser is released, the film sensitivity is automatically set high and the strobe light source 4 of the strobe light source 4 is set in the shortest time. If the reference value is exceeded even if the light emission is stopped, a means for automatically lowering the film sensitivity setting is provided to widen the automatic adjustment range of the exposure amount. At this time, if the reference value is also automatically reset according to the change in the film sensitivity setting, an image with an appropriate exposure amount can be obtained without performing a complicated work.

Further, the present invention can be applied not only to infrared fluorescence imaging but also to fluorescence imaging with visible light. In this case, infrared fluorescence and visible fluorescence usually differ in the amount of ambient light reduction and fluorescence leakage. By providing different reference values corresponding to the respective shooting modes, an image with a more appropriate exposure amount can be obtained. Also, for example, ISO10
For low sensitivity settings equivalent to 0, ISO200, and ISO400, set a reference value assuming color photography,
For high sensitivity settings corresponding to SO800 and ISO1600, a reference value may be set based on the premise of fluorescence imaging.

Further, instead of detecting the reflected light from the image pickup means, a light splitting means for splitting a part of the light flux is provided in the optical path on the way to the image pickup means of the photographing optical system, and the separated light flux is detected. Alternatively, the exposure amount may be set.
Further, a means for arranging density filters having different densities may be provided in front of the light amount sensor 15 depending on the photographing mode.

[0026]

As described above, the fundus examination apparatus according to the present invention can be used for both color photography and fluorescence photography.
It is possible to always obtain an image with an appropriate exposure amount, reduce the number of shooting failures, and perform efficient inspections. Also, by receiving light with an appropriate exposure amount, fine resolution in the density direction can be used for imaging. Since it is possible to obtain a lot of information, more precise diagnosis is possible. Further, since the exposure operation is not required when changing the shooting mode, the shooting mode can be changed easily and the apparatus can be operated efficiently.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment.

FIG. 2 is an explanatory diagram of a fundus image during color photography.

FIG. 3 is a graph showing a density distribution during color photography.

FIG. 4 is an explanatory diagram of a fundus image during fluorescence photography.

FIG. 5 is a graph showing a concentration distribution during fluorescence photography.

[Explanation of symbols]

 1 Light source for observation / alignment 4 Light source for still image shooting 5 Ring aperture 6 Exciter filter 9 Barrier filter 12 High-definition camera 13 High-sensitivity camera 15 Light intensity sensor 16 Control means 17 Sensitivity selection switch 18 Shooting switch 19 Mode selection switch 20 Power supply Controller 21 Image storage means 23 Television monitor

Claims (3)

[Claims] 1. A fundus illuminating device having a strobe light source and a removable first band-pass filter, a fundus imaging device having a removable second band-pass filter, and a part of light reflected from the fundus. And a light emission control means for detecting that the received light quantity of the photographing light quantity detection means by the light emission of the strobe light source has reached a reference value and controlling the light emission of the strobe light source. A fundus examination apparatus characterized in that the light emission control means changes the reference value of the received light amount in accordance with the insertion / removal of the first and / or second bandpass filter. 2. The fundus illuminating means and the fundus imaging means include at least two types of bandpass filters having different characteristics, and the reference value is changed according to the type of the bandpass filter. Fundus examination device. 3. The fundus according to claim 1, further comprising switching means for automatically switching between the sensitivity of the camera and the reference value when the received light amount exceeds the reference value or does not reach the reference value. Inspection device.