JP5835264B2 - Non-mydriatic fundus imaging system and non-mydriatic fundus imaging method - Google Patents

Description

  The present invention relates to a fundus photographing system and a fundus photographing method for photographing the fundus of the retina and the like for diagnosing diseases related to the retina and the progress of arteriosclerosis in an ophthalmological clinic and the like. The present invention relates to a fundus imaging system and a fundus imaging method that can be performed.

Conventionally, a fundus examination is generally performed as an examination item of an ophthalmological examination at a hospital or the like or as an examination item of a clinical examination. The fundus examination apparatus used in this examination is generally a non-mydriatic camera that observes the subject's eye with near-infrared rays, positions and focuses for fundus photography, and then uses visible light as an illumination light source. It is used for.
Since the pupil constricts with visible light, a near-infrared light source is used for the purpose of preventing this, while visible light is used as an illumination light source to accurately perform examinations and diagnoses during fundus photography.
In some cases, mydriatics are observed using mydriatic agents, and the fundus is photographed using a mydriatic camera, but the burden on the subject's eyes on mydriatic agents is large, and the examination itself takes time and effort. It was difficult to carry out simple examinations and diagnoses with less burden.
Under such circumstances, many inventions related to the fundus imaging apparatus have been proposed.

For example, Patent Document 1 discloses a fundus camera having a light source in which a plurality of types of LEDs having different wavelengths are arranged in a ring shape under the name of “ring light fundus camera”. Specifically, different wavelengths are disclosed having white light, green light, blue light, and infrared light. Further, a combination of a halogen lamp, a filter, and a capacitor as a light source is also disclosed.
According to the invention disclosed in Patent Document 1, by arranging the light source in a ring shape, the visual light path and the illumination light path are mainly on the same optical axis, and the illumination light can be supplied by this ring-shaped light source. it can.

Further, Patent Document 2 includes a plurality of LED chips arranged in a ring shape and discretely as a visible light source under the name “fundus camera”, and light emitted from the LED chips arranged in front of the LED chips. It is composed of a fluorescent material that emits excited fluorescence and a ring-shaped optical element that reflects a part of the light emitted from the LED chip, and a part of the light reflected by this optical element irradiates the fluorescent material again. An invention using what is configured as described above is disclosed.
In the invention configured as above, white light having high color rendering properties can be obtained by light that becomes white light by mixing the blue light emitted from the LED chip and the light emitted from the fluorescent material excited by the blue light. it can. Furthermore, since part of the light reflected by the optical element that reflects the light from the LED chip can excite the fluorescent material again, it is possible to emit white light with high color rendering properties more efficiently. It is.

Further, in Patent Document 3, an illumination optical system that illuminates the fundus of the subject's eye with the name “ophthalmologic imaging apparatus”, two or more types of LED light emitting elements that emit different wavelengths, and the pupil position and optical state of the subject's eye In an ophthalmologic photographing apparatus having a pupil aperture and a ring-shaped opening arranged at a conjugate position, two or more types of LED light emitting elements are arranged at equal intervals in the opening.
In the invention configured as described above, the observation light source and the photographing light source can be shared, and the fundus can be illuminated efficiently and uniformly with a simple structure.

JP 2007-29726 A JP 2010-119448 A JP 2008-212327 A

However, these conventional fundus photographing cameras use light sources such as LEDs of different wavelengths while arranging the light sources in a ring shape, so that even non-mydriatic cameras can share observation light sources and photographing light sources. However, multiple light sources have different wavelengths, that is, use long-wavelength light sources such as infrared light and near-infrared light as observation light sources, and visible light or white light as imaging light sources. Compared with infrared light or near infrared light, a light source with a short wavelength was used.
Even if light sources with different wavelengths are arranged in a ring shape and used in common, there will be a problem of chromatic aberration due to different wavelengths, and even if focusing with a long wavelength light source, a short wavelength light source will be used for shooting. There is a problem that it is difficult to adjust the focus with high accuracy by using it.
In addition, there is a plurality of light sources having different wavelengths constituting at least one ring-shaped light source, and it is necessary to provide a light source for each different wavelength, and it is necessary to control the amount of light for each different wavelength. At the same time, there is a problem that the control becomes complicated.
Furthermore, it is necessary to provide a light source with different wavelengths and control the amount of light of the light sources with different wavelengths, and it is difficult to realize a fundus photographing apparatus that can be inspected with a simple operation at a low price. was there. Therefore, there is a problem that it cannot be widely spread.

  The present invention has been made to solve such problems, and can be simplified, miniaturized, and reduced in cost, can be easily operated, and can adjust the focus with high accuracy. It is an object of the present invention to provide a fundus imaging system and method that can easily control the amount of light and have a very small variation in image quality.

In order to achieve the above object, a non-mydriatic fundus imaging system according to a first aspect of the present invention includes a visible light emitting element light source that irradiates the fundus of a subject's eye, and visible light emitted from the visible light emitting element light source. An image sensor that receives reflected light from the fundus to capture a fundus image, a focus adjustment unit that adjusts the focus of the fundus image captured by the image sensor by driving a focusing lens, and data relating to the fundus image. A non-mydriatic fundus imaging system comprising: a control device having an image processing unit that receives and processes an image so as to be displayed; and a display that receives the data processed by the control device and displays the fundus image, The control device includes: a light amount adjusting unit capable of adjusting a light amount of the visible light emitting element light source to a weak light amount that does not cause at least a pupil of the eye to be examined during fundus observation; and a sensitivity for adjusting the sensitivity of the imaging element Comprising a settling unit, and the imaging instruction section for instructing to expose a certain time the reflected light to a predetermined shorter than the time required to miosis of the pupil with respect to the imaging device imaging the fundus oculi, the said The visible light emitting element light source is a light source for focusing the fundus image and a light source for photographing.
In the non-mydriatic fundus photographing system configured as described above, one type of visible light emitting element light source serves as a light source for focusing before fundus photographing and simultaneously as a light source for photographing. In addition, the control device acts so as to focus the fundus image of the eye to be inspected irradiated with the visible light emitting element light source with high accuracy, and the imaging device acts so as to acquire the fundus image adjusted with high accuracy as image data. To do. The control device receives the image data of the fundus image, performs image processing, and operates so that the display displays the fundus image using the image processed image data.
Further, the control device acts to adjust the light amount of the visible light emitting element light source and / or the sensitivity of the imaging element.
In addition, the visible light emitting element light source as used in this application means the light emitting element light source which can radiate | emit visible light. Further, the visible light is, according to the definition of JIS Z8120, the lower limit of the wavelength of the electromagnetic wave corresponding to the visible light is approximately 360 to 400 nm, and the upper limit is approximately 760 to 830 nm. As long as it is possible to perform fundus examination and diagnosis, any color of visible light may be used, but white (colorless and transparent) light is desirable in view of performing highly accurate examination and diagnosis. . In this case, a single-wavelength white light-emitting element may be used, but a white light-emitting element having two or more wavelengths capable of emitting complementary colors such as blue and yellow and red and green is desirable. Furthermore, it is most desirable to be a white (colorless and transparent) light-emitting element light source with high color rendering properties having light of all wavelengths close to sunlight. Moreover, even if what emits light by exciting a fluorescent substance will not be specifically limited if it emits visible light as a light emitting element.
Note that the visible light emitting element light source includes an LED, an organic EL, a laser, and the like.

The fundus imaging system according to another aspect of the present invention is the non-mydriatic fundus imaging system according to claim 1 , wherein the control device receives data relating to the fundus image received from the image sensor and captures the entire fundus image. Image processing is performed so as to be displayable for confirmation, and image processing is performed so that a partially enlarged image of the fundus can be displayed for focus confirmation. The display divides the screen into the entire fundus image for confirming the photographing position and the focus confirmation. A partial enlarged image of the fundus is simultaneously displayed.
In the non-mydriatic fundus imaging system, which is another invention configured as described above, in addition to the operation of the invention according to claim 1 , the control device receives data related to the fundus image received from the image sensor. In addition to performing image processing so that the entire fundus image can be displayed for confirmation of the shooting position, it also functions to perform image processing so that a partially enlarged image of the fundus can be displayed for focus confirmation, and the display divides the screen to check the shooting position. The entire fundus image and a partially enlarged image of the fundus for focus confirmation are displayed simultaneously .

The invention described in claim 2 is the non-mydriatic fundus photographing system according to claim 1, wherein the visible light emitting element light source is a light emitting element formed on the plurality of light emitting elements or annular arranged annularly Thus, the reflected light from the fundus has an optical path formed by a hole formed in the center of the plurality of light emitting elements arranged in a ring or the light emitting elements formed in a ring.
In the non-mydriatic fundus imaging system configured as described above, in addition to the operation of the invention described in claim 1 , the visible light emitting element light source includes a plurality of light emitting elements or annular light emitting elements. When they are arranged in an annular shape or formed in an annular shape, they act to form a hole in the center thereof, and act to guide reflected light that irradiates the fundus of the eye to be examined. .

The invention described in claim 3 is the non-mydriatic fundus photographing system according to claim 1, wherein the visible light emitting element light source comprises at least one visible light emitting element, emitted from the visible light emitting element light source The visible light emitted irradiates the fundus of the subject's eye via a splitter or a perforated mirror, and the reflected light from the fundus is received by the image sensor via the splitter or perforated mirror.
In the non-mydriatic fundus imaging system configured as described above, in addition to the operation of the first aspect of the invention, the visible light emitting element light source includes at least one visible light emitting element and is formed in an annular shape. Therefore, a splitter is provided, and it is utilized that the splitter has an action of transmitting a part of light and reflecting a part thereof. That is, the splitter acts to reflect visible light emitted from the visible light emitting element light source and to transmit reflected light from the fundus of the subject's eye.
Alternatively, a perforated mirror may be used instead of the splitter. This perforated mirror has a hole in the center and a periphery of the perforated mirror, and the periphery of the perforated mirror is a reflection mirror. The reflected light is transmitted through a hole drilled in the center and guided to the image sensor. Therefore, this perforated mirror has the effect | action which guide | induces the visible light from a visible light light emitting element light source to a fundus, and guides the reflected light from a fundus to an image sensor.

According to a fourth aspect of the present invention, there is provided a step of setting a subject eye for photographing a fundus image of the subject eye, a step of adjusting sensitivity of an image sensor for photographing the fundus image, and the fundus image. Adjusting the amount of light of a visible light emitting element light source for photographing to a weak amount of light so that the pupil of the eye to be examined does not cause at least miosis; and irradiating the fundus with visible light from the visible light emitting element light source; A step of positioning the fundus of the eye to be examined using visible light from the visible light emitting element light source, and an image of the fundus image captured by the imaging element using visible light from the visible light emitting element light source. A step of adjusting a focus; a step of adjusting a sensitivity of an image sensor for capturing the fundus image; a step of adjusting a light amount of a visible light emitting element light source for capturing the fundus image; and the visible light emission. element A step of photographing by exposure for a certain period of time the reflected light to a predetermined shorter than the time required for the fundus image to the miosis of the pupil with visible light from a source, and has a.
The non-mydriatic fundus imaging method configured as described above is based on the non-mydriatic fundus imaging system described in claim 1 as a method invention. As a specific action, one kind of visible light emitting element light source acts as a light source for photographing at the same time as a light source for focusing before fundus photographing. Therefore, the steps of positioning the fundus of the eye to be examined, the step of adjusting the focus of the fundus image captured by the imaging device, and the step of capturing the fundus image are all performed using visible light emitted from the same visible light emitting element light source. Acts to be executed.
Further, between the step of adjusting the focus of the fundus image and the step of capturing the fundus image, the step of adjusting the sensitivity of the image sensor for capturing the fundus image to be inserted again and the visible image for capturing the fundus image. By adjusting the light amount of the light emitting element light source, the combination of the imaging element sensitivity and the light amount of the visible light emitting element light source can be individually adjusted in the fundus image focus adjustment step and the fundus image photographing step. .

According to the first aspect of the present invention, since one type of visible light emitting element light source is used as a focusing light source before photographing the fundus and simultaneously as a photographing light source, alignment of the fundus for photographing is performed. The fundus image focus adjustment and fundus image shooting can all be performed using the same light source. Moreover, by using the same light source, it is possible to share most of the optical path when the visible light emitted from the visible light emitting element light source irradiates the fundus of the eye to be examined and the optical path when the visible light is reflected from the fundus. Therefore, the fundus imaging system can be simplified, reduced in size, and reduced in cost, and can be easily operated.
Furthermore, by using the same light source, there is no need for chromatic aberration correction, which was necessary when a focusing light source and a photographing light source having different wavelengths were used separately. It is possible to make adjustments, and it is possible to facilitate the light quantity control by using one type of light source.
By integrating these effects, it is possible to perform fundus photography with extremely small variations in image quality.
In the present invention, the fundus examination can be performed with non-mydriasis without using a mydriatic agent, so that the examination eye can be easily and safely performed in a short time with less invasiveness and less mental burden. It is possible.
Further, since it is possible to adjust the light amount of the visible light emitting element light source and / or the sensitivity of the image pickup element, the fundus positioning of the eye to be examined, the focus adjustment of the fundus image, and the fundus image shooting are performed for each operation. In addition, the light amount of the visible light emitting element light source and / or the sensitivity of the imaging element can be adjusted. Therefore, it is possible to select an appropriate light amount of the visible light emitting element light source and sensitivity of the imaging element according to the application, and it is possible to improve the image quality of the fundus image.

In the other inventions, in addition to the effect of the invention described in claim 1 , since the entire fundus image for confirming the photographing position and the partially enlarged fundus image for confirming the focus are separately displayed on the display, the photographing position confirmation is performed. Since the focus adjustment can be performed with reference to the fundus partial enlarged image for focus confirmation while viewing the entire fundus image, the fundus image can be taken immediately after the focus adjustment.
Since the entire fundus image for confirming the shooting position and a partially enlarged fundus image for confirming the focus are displayed on the display at the same time with the same light emitting element light source, visual recognition of the fundus image that is about to be photographed during focus adjustment High accuracy and easy.
Furthermore, since the fundus partial enlarged image for focus confirmation is displayed by the visible light emitting element light source, the focus adjustment can be performed easily and with high accuracy compared to the image using infrared light or near infrared light.

In the invention described in claim 2 of the present invention, in addition to the effect of the invention described in claim 1 , a light guide hole formed in the center of a visible light emitting element light source configured in an annular shape is provided on the fundus of the eye to be examined. By including it in the optical path of the reflected light after irradiation, it is possible to simplify the formation of the optical path, so that the fundus imaging system can be further simplified, reduced in size, and reduced in cost.

In the invention according to claim 3 of the present invention, the same effect as that of the invention according to claim 1 can be exhibited.
Further, in comparison with the invention described in claim 2 , since the visible light emitting element light source does not have to be arranged or formed in an annular shape, the effect of increasing the degree of freedom of arrangement and shape of the visible light emitting element light source is improved. It can be demonstrated. However, since there is no light guide hole obtained by arranging or forming it in an annular shape, it is necessary to provide a splitter or a perforated mirror, and in this respect, the effects of simplification, miniaturization, and cost reduction are exhibited. Can be an impediment.

Since the invention described in claim 4 of the present invention is an invention that captures the invention described in claim 1 as a method invention, the effect is the same as the effect of the invention described in claim 1.
Further, the combination of the imaging device sensitivity and the light amount of the visible light emitting element light source can be individually adjusted in the fundus image focus adjustment step and the fundus image photographing step. Therefore, for example, in the case of focus adjustment of the fundus image, the light intensity of the visible light emitting element light source is decreased while increasing the imaging element sensitivity in consideration of performing the non-mydriatic without using a mydriatic agent. When the fundus image is captured, increasing the sensitivity of the image sensor increases noise, so the sensitivity of the image sensor is decreased and adjustments are made to increase the amount of light from the visible light source. Excellent effect in any case.
As described above, since the sensitivity of the imaging device and the light amount of the visible light emitting device light source can be adjusted for each use and operation, the image quality of the fundus image can be further improved.

1 is a configuration diagram of a non-mydriatic fundus imaging system according to a first embodiment of the present invention. It is a flowchart regarding the non-mydriatic fundus imaging method according to the second embodiment of the present invention. It is a block diagram of the non-mydriatic fundus imaging system according to the third embodiment of the present invention. (A) thru | or (f) are all the conceptual diagrams which show the example of arrangement | positioning of visible light LED in the visible light LED light source which concerns on embodiment of this invention. It is a flowchart regarding the non-mydriatic fundus imaging method according to the fourth embodiment of the present invention.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of a non-mydriatic fundus imaging system according to the first embodiment of the present invention. Hereinafter, in the present specification, when “fundus photographing system” is simply indicated, it means “non-mydriatic fundus photographing system”, and when “fundus photographing method” is indicated, “non-mydriatic fundus photographing method” is referred to. means.
In FIG. 1, a fundus imaging system 1 includes a visible light LED 5 provided for inspecting and photographing the fundus by irradiating visible light from a pupil 3 of an eye 2 to be examined. A plurality of visible light LEDs 5 having the same specifications are arranged on the mount 6 at equal intervals in a ring shape. Visible light emitted from the visible light LEDs 5 passes through the objective lens 4 and passes through the pupil 3 to the eye 2 to be examined. Irradiate the fundus. Reflected light from the fundus is again transmitted through the objective lens 4, passes through the central hole formed by the visible light LED 5 arranged in an annular shape as a light guide hole, and passes through the focusing lens 7 and the imaging lens 8. Then, the light enters the image sensor 10 stored in the housing 9.
In the present embodiment and other embodiments, the visible light LED 5 is used as the visible light emitting element light source. However, the visible light LED 5 is not limited to the LED as long as the light emitting condition is satisfied. Etc.
As shown in FIG. 1, the irradiation light path 11 for the irradiation light from the visible light LED 5 to the fundus of the eye 2 to be examined and the reflection light path 12 for the reflection light from the fundus of the eye 2 to the imaging device 10 all have the same optical axis. Can be placed on top. Therefore, the fundus imaging system 1 can be simplified, downsized, and reduced in cost.
Data regarding the fundus image formed by the image sensor 10 is subjected to image processing so that it can be displayed on the display 19 by the image processing unit 18 of the control device 13. Further, the photographed fundus image is processed by the image processing unit 18 and then stored in the database 22 so as to be readable as image data 23.

  The visible light LED 5 may be any LED (Light Emitting Diode) light source that emits visible light as long as fundus examination and diagnosis are possible, but it is desirable to emit colorless transparent light (white for convenience). A single-wavelength white LED may be used, but considering the accuracy of inspection and diagnosis, a white LED having two or more wavelengths that can emit complementary colors such as blue and yellow and red and green is desirable. Furthermore, it is most desirable to be a white (colorless and transparent) LED light source with high color rendering properties having light of all wavelengths close to sunlight. Moreover, even if what emits light by exciting a fluorescent substance, if it emits visible light as LED, it will not specifically limit. This visible light LED 5 is a visible light LED 5 of one type, that is, the same specification, and is a light source for focusing the fundus image as well as an imaging light source. Therefore, during fundus observation such as fundus alignment and focus adjustment, and fundus photographing It is possible to take a clear and high-quality fundus image without correction of chromatic aberration.

As a characteristic of the visible light LED 5, it is necessary to be able to realize at least a weak light amount that does not cause miosis. Specifically, it is desirable that the fundus can irradiate weak light of 10-50 Lx (lux) or less. The difference in illuminance depends on individual differences, but it is important to realize illuminance that does not cause miosis.
Note that miosis is a phenomenon in which the pupil is reduced in diameter, but it is sufficient that the minimum pupil diameter (about 3.3 mm) that allows the fundus imaging system to capture the fundus is maintained. In other words, the illuminance that does not cause miosis is the illuminance (light quantity) that can maintain the minimum pupil diameter that allows fundus photography.
Furthermore, since the visible light LED 5 is also used for fundus photographing, it is necessary to be able to realize a light intensity with sufficient intensity for the photographing. The amount of light sufficient for photographing is affected by the sensitivity of the image sensor 10 and the exposure time, which will be described later. Therefore, it is necessary to determine the specifications in consideration of them. When the sensitivity of the image sensor 10 is high, there is an influence of noise. Further, since a still image is taken when the fundus image is taken, it is possible to take the fundus image within a time period in which miosis does not occur by increasing the light amount and shortening the exposure time. The specification of the light quantity of the visible light LED 5 including these elements should be determined.
Note that the amount of light of the visible light LED 5 has a relationship with a diaphragm, which will be described later, and may be the visible light LED 5 that can realize the above-described illuminance and light amount by operating the diaphragm.
The image sensor 10 is a CCD (Charge-coupled Device) or CMOS (Complementary).
Metal Oxide Semiconductor) is a typical example, but is not particularly limited thereto, and any element can be used as long as it is an imageable element.
Since it is necessary to reduce the illuminance of the visible light LED 5 to suppress the miosis of the eye to be examined, the sensitivity of the imaging device 10 is required to be high especially during fundus observation such as fundus alignment and focus adjustment. Specifically, the higher sensitivity is naturally desirable, and the standard is considered to be about ISO 100,000. However, when the sensitivity is high, noise is also easily superimposed, so that the visible light with reduced illuminance to such an extent that no miosis occurs. The sensitivity is such that the fundus can be observed with the light LED 5.

In addition to the image processing unit 18, the control device 13 adjusts the focal point of the fundus image by driving the light amount adjusting unit 14 that adjusts the light amount of the visible light LED 5 during the fundus examination of the eye 2 and the focusing lens 7. A focus adjustment unit 15, a sensitivity adjustment unit 16 that adjusts the sensitivity of the imaging element 10, and an imaging instruction unit 17 that instructs the timing at which the fundus of the subject eye 2 is imaged by the imaging element 10 are provided.
The light amount adjusting unit 14 of the control device 13 adjusts the light amount by adjusting the voltage and current applied to the visible light LED 5. Alternatively, the amount of light may be adjusted by PWM (Pulse Width Modulation). The sensitivity adjustment unit 16 of the control device 13 adjusts the sensitivity of the image sensor 10. Specifically, the sensitivity adjuster 16 adjusts the sensitivity by changing the amplification degree of the signal by the reflected light received by the image sensor 10. It is. Increasing the amplification level increases the sensitivity, and decreasing the amplification level decreases the sensitivity.
The focus adjustment unit 15 of the control device 13 can perform automatic focus adjustment (autofocus) using a passive method. Specifically, the focus is adjusted by performing a calculation process based on the fundus image obtained by the reflected light received by the image sensor 10. This automatic focus adjustment technique using the passive method has already been widely adopted in digital cameras and the like.
Further, the image processing unit 18 of the control device 13 not only processes data relating to the fundus image so that the image can be displayed on the display 19, but also performs a process of enlarging a part of the fundus image, and displays the focus confirmation screen. A function for displaying as 20 and a function for transmitting the entire image of the fundus image as a photographing position confirmation screen 21 and a partly enlarged image as a focus confirmation screen 20 and simultaneously transmitting image data related thereto to the display 19 Is also provided. An enlarged area 21 a in the shooting position confirmation screen 21 shown in FIG. 1 is displayed as the focus confirmation screen 20. The setting of the enlargement area 21a can be performed by the image processing unit 18 including the size of the area.

  The display 19 has a function of displaying an image relating to the fundus image obtained by the imaging device 10, and image data relating to the photographing position confirmation screen 21 and image data relating to the focus confirmation screen 20 by the image processing unit 18 of the control device 13. Are simultaneously transmitted, the screen is divided to display both the shooting position confirmation screen 21 and the focus confirmation screen 20 as a plurality of screens.

Next, a method for photographing the fundus of the eye 2 to be examined using the fundus photographing system 1 will be described with reference to FIG. FIG. 2 is a flow chart relating to a fundus imaging method according to a second embodiment in which the fundus imaging system according to the first embodiment of the present invention is regarded as a method invention.
First, in step S1, the subject 's eye 2 to be examined is set at a predetermined position in the vicinity of the objective lens 4 of the fundus imaging system 1. The examination engineer who operates the fundus imaging system 1 adjusts the sensitivity of the image sensor 10 as step S2 after completing the setting of the eye 2 to be examined. The sensitivity adjustment may be set to a preset sensitivity mode. The sensitivity of the image sensor 10 is adjusted to a sensitivity suitable for fundus positioning, fundus image focus adjustment, and fundus photographing after step S4. In step S3, the light amount of the visible light LED 5 is adjusted. The adjustment of the light quantity of the visible light LED 5 is also a process for making the light quantity suitable for the operation after step S4. Since the sensitivity of the imaging device 10 and the light amount of the visible light LED 5 are affected by each other, step S2 and step S3 may be executed first, or may be executed simultaneously or alternately.
The timing of the step S2, 3 and the lighting of the visible light LED 5 is not particularly limited as long as it is turned on after the step S3 at the latest. However, the step S2, 3 is performed after the visible light LED 5 is turned on. For example, the visible light LED 5 may be gradually increased from the minimum light amount while watching the display 19 so as not to hurt the subject's eye 2 to be examined. Furthermore, if there are few individual differences depending on the subject, steps S2 and S3 may be completed prior to step S1 and set in advance. In other words, the order of steps S1 to S3 is not fixed, and may be appropriately executed without being limited to the order as long as the test can be safely performed on the subject. However, since the visible light LED adjusted in step S3 is used in all processes in steps S4 to S6, it is important to sufficiently adjust the visible light LED.

Note that shutter speed (exposure time) can be considered as another factor when photographing a fundus image using the fundus photographing system 1. The lower the shutter speed, the lower the sensitivity of the image sensor 10 and the lower the amount of light of the visible light LED 5. However, in the fundus imaging system 1 according to the present embodiment, the fundus positioning and fundus focus adjustment in steps S4 and S5 are performed manually or automatically by the laboratory technician using the display 19, In this regard, there is no concept of shutter speed like a still camera.
However, the concept of shutter speed is necessary when taking a still image of the fundus image in step S6. This is because if the shutter speed is set to a low speed (long time) and is set slower than the speed of the miosis of the pupil that reacts to visible light, the fundus image cannot be captured.
Therefore, in the fundus imaging system according to the present embodiment, only the sensitivity adjustment of the image sensor 10 and the light amount adjustment of the visible light LED 5 are performed while the concept of the shutter speed is not an independent essential component but an accompanying optional element. Thus, a configuration example is shown in which all of fundus positioning, fundus image focus adjustment, and fundus imaging are performed. Therefore, the shutter speed (exposure time) is not excluded.

Next, step S4 in FIG. 2 is a step of positioning the fundus. As shown in FIG. 1, since the display 19 can divide the screen into two, refer to the photographing position confirmation screen 21 so as to show the entire fundus image as the photographing position confirmation screen 21. However, the fundus can be positioned.
Step S5 is a step of adjusting the focus of the fundus image. As described above, a divided screen is displayed on the display 19, one is a shooting position confirmation screen 21 showing the entire fundus image, and the other is a focus confirmation of an enlarged image of a part of the fundus image. Can be displayed as a display screen 20. In order to adjust the focus, it is desirable to display an enlarged image as much as possible. Therefore, a clearer and higher-quality fundus image can be obtained by performing focus adjustment while referring to the focus confirmation screen 20. Can do it. The focus can be adjusted by changing the position of the focusing lens constituting the fundus photographing system 1.
Further, as described above, automatic focus may be used as the focus adjustment method. As an autofocus technique, there are an active method and a passive method, but in the embodiment of the present application, it is desirable to use a passive method that does not need to irradiate the subject (eye to be examined) with infrared rays, ultrasonic waves, or the like. In the passive method, the obtained fundus image can be processed and focused. As long as it is a passive method, any method such as a phase difference detection method or a contrast detection method may be used.

The final step S6 is a step of taking a fundus image. When a clear image focused on by adjusting the focus is displayed on the focus confirmation screen 20 of the display 19, the shutter is released with respect to the image sensor 10 in order to take a still image. To release the shutter means that the image sensor 10 exposes the reflected light for a certain period of time.
Note that the visible light LED 5 may be turned on as it is or may be turned off once after the focus adjustment in step S5 before the fundus image is captured in step S6. If the white LED 5 is turned on again at the time of shooting and shooting is performed, or if an aperture and aperture adjustment unit described later are provided, the aperture may be adjusted at that timing, or the visible light LED 5 Only the aperture may be adjusted while the is on.
In the image sensor sensitivity adjustment process in step S2 and the visible light LED light quantity adjustment process in step S3, the visible light LED 5 does not necessarily have to be lit and adjusted. It is also possible to adjust by setting the light quantity of the visible light LED and setting it.
Therefore, in the processes of Step S6 and Step S7, it is not always necessary to perform the adjustment by turning on the visible light LED, and the sensitivity and the light amount can be set in advance and the adjustment can be performed by setting the sensitivity. Accordingly, the visible light LED may be turned on immediately before step S4 to execute steps S4 and S5.

  In the first embodiment, the imaging instruction unit 17 of the control device 13 is used to transmit a signal for instructing the imaging element 10 to expose the reflected light for a predetermined period of time that is determined in advance. As described above, since this certain time needs to be shorter than the time required for pupil miosis, it is desirable to set in advance as a time that satisfies the condition.

In the first embodiment, no stop is provided in the system of the optical system, but this may be provided, for example, between the focusing lens 7 and the imaging lens 8. By providing a diaphragm, when controlling the amount of light from the visible light LED 5, it is possible not only to control by the applied voltage, current and pulse width, but also by adjusting the diaphragm. Accordingly, it is possible to further finely adjust the environment in fundus photography. The diaphragm can be controlled by providing a diaphragm adjusting unit in the control device 13.
The diaphragm may have a structure used for a digital camera or the like. Further, the specific value of the aperture is not determined unconditionally because it depends on the light amount of the visible light LED 5, the sensitivity of the image sensor 10, the exposure time, etc., but indirectly without changing the light amount of the visible light LED 5 itself. Since the amount of light can be adjusted, for example, the amount of light emitted from the visible light LED 5 can be kept constant, and the amount of irradiation light can be changed by adjusting the aperture. By controlling the current or the pulse width and adjusting the diaphragm at the same time, it is possible to adjust the irradiation light amount in more detail.
Since the diaphragm can adjust not only the amount of light but also the depth of field, for example, by reducing the diaphragm while increasing the amount of light emitted from the visible light LED 5, the same irradiation light amount can be obtained. It is also possible to obtain an image with a deep depth of field. That is, it becomes possible to reduce the out-of-focus blur.
Regarding the adjustment of the diaphragm, the fundus imaging system according to the second embodiment already described, as well as the fundus imaging method according to the second embodiment described later, and the fourth embodiment described later will be described. Similarly, the fundus photographing method according to the embodiment can be employed.

There are several cases where an aperture adjustment step is added to the fundus imaging method. For example, it can be considered between step S1 and step S2, between step S2 and step S3, or between step S3 and step S4. Since these steps S2 and S3 are steps for setting conditions for positioning, focus adjustment, or fundus photography, when adding an aperture adjustment step, they can be handled in the same way and added before and after any step. You may do it.
However, there may be a case where the aperture is adjusted before the fundus photographing process in step S6. There may be a case where the exposure to the image sensor is enhanced by performing an adjustment to open the aperture without adjusting the image sensor sensitivity or the LED light amount at the time of shooting. By enhancing the exposure in this way, a clearer fundus image can be taken and the image quality can be improved.
According to this embodiment, the visible light LED light source is used not only for fundus observation such as fundus positioning in step S4 and focus adjustment of the fundus image in step S5, but also for fundus photographing in step S6. By sufficiently adjusting the element sensitivity and adjusting the amount of light of the visible light LED, an operation for changing the light source is unnecessary, and the fundus can be inspected and diagnosed easily and in a short time.

Next, a fundus imaging system according to a third embodiment of the present invention will be described with reference to FIG.
FIG. 3 is a configuration diagram of a fundus imaging system according to the third embodiment of the present invention. However, since the control device 13, the display 19, and the database 22 shown in FIG. 1 have the same configuration, illustration and description thereof are omitted here.
In FIG. 3, the fundus imaging system 31 according to the third embodiment differs from the fundus imaging system 1 according to the first embodiment in the configuration of the visible light LED light source. In the first embodiment, the visible light LEDs 5 arranged in a ring shape are used. However, in the third embodiment, at least one visible light LED 35 is provided and is limited to be configured in a ring shape. Not what you want.
As shown in FIG. 3, it is similarly arranged on the mount 36, but only one visible light LED 35 may be installed. In this case, since the light guide hole formed in the center does not exist because it cannot be arranged in a ring shape, the imaging element 40 from the irradiation light path 41 to the irradiation light from the visible light LED 35 to the fundus of the eye 2 to be examined and the fundus of the eye 2 to be examined. It is impossible to arrange all the reflected light paths 42 for the reflected light up to the same optical axis. Therefore, the splitter 43 is disposed on the irradiation light path 41 and the reflection light path 42, the irradiation light of the visible light from the visible light LED 35 is reflected by the splitter 43 and transmitted through the objective lens 34, and the fundus of the eye 32 to be examined is transmitted from the pupil 33. The reflected light is transmitted through the objective lens 34, this time through the splitter 43, through the focusing lens 37 and the imaging lens 38, and imaged by the image sensor 40.
Since the splitter 43 refers to a member that reflects part of light while transmitting part of light, there is also irradiation light that is transmitted without being reflected by the splitter 43 when visible light from the visible light LED 35 is irradiated. Needless to say, the reflected light from the fundus is also reflected by the splitter 43 without being transmitted.
If the splitter 43 is used in this way, the visible light LED 5 does not need to be arranged in a ring shape, but the irradiation light path 41 needs to be placed coaxially with the reflected light path 42 by providing the splitter 43 or the like. In such a case, since the irradiation light and the reflected light are attenuated, there is a possibility that the amount of light that can be received by the image sensor 40 is small.

  In the third embodiment, the splitter 43 is used. However, the same effect can be obtained by using a perforated mirror instead of the splitter 43. That is, the visible light irradiation light from the visible light LED 35 is reflected by the mirror portion formed around the perforated mirror and irradiates the fundus of the eye 2 to be examined, and the reflected light reflected from the fundus is the perforated mirror. The light is received by the image sensor 40 through a hole formed in the center of the image sensor.

FIGS. 4A to 4F are conceptual diagrams showing an arrangement example of visible light LEDs in the visible light LED light source according to the embodiment of the present invention.
One of the biggest features of the fundus imaging system according to the embodiment of the present invention is that one type of visible light LED light source is used as a light source for focusing a fundus image and also as an imaging light source. The visible light LED is relatively easy to control the amount of light. That is, both strong light and weak light can be controlled by voltage, current, and pulse width of a constant frequency. Therefore, by controlling the amount of light that does not cause miosis, it is possible to perform fundus positioning and focus adjustment that have been performed using infrared rays or near infrared rays. In this case, since inspection can be performed with visible light, it is easier for an inspection engineer to visually recognize the degree of focus matching and deviation. In addition, since it is visible light, the fundus can be photographed as it is after focus adjustment without changing the light source.
In the fundus imaging system according to the first embodiment described with reference to FIG. 1, the visible light LED light source having such advantages has a plurality of visible light LEDs 5 a as shown in FIGS. 4 (a) to 4 (d). -5d is arranged in an annular shape. By arranging in an annular manner in this way, the light guide hole 6a can be formed in the center thereof, the reflected light from the fundus of the eye 2 to be examined can be passed, and all of the irradiation light path 11 and the reflection light path 12 can be passed. They can be arranged on the same optical axis. If it is formed in a ring shape, it may be eight visible light LEDs 5a, four visible light LEDs 5b, three visible light LEDs 5c, or two visible light LEDs 5d as shown in (a). The number is not particularly limited, but it is preferable to arrange the fundus image so that no shadow is formed.

  Further, as shown in FIG. 4E, the visible light LED 5e itself may be formed in an annular shape. In this case, the element has a circular shape and emits light in a ring shape. That is, when the visible light LED light source is configured in a ring shape, there are two types of cases where a plurality of visible light LEDs are arranged in a ring shape and a case where the visible light LEDs themselves are formed in a ring shape. If there are holes, the same action and effect can be exhibited.

  Finally, FIG. 4 (f) shows an example of the visible light LED of the fundus imaging system according to the third embodiment described with reference to FIG. 3, and shows a case where only one visible light LED 5f is provided. is there. In the third embodiment, since the splitter 43 or the perforated mirror is provided, the arrangement of the visible light LED itself is not particularly limited, and the same operation and effect can be achieved even if a plurality of visible light LEDs are provided. Can do.

FIG. 5 is a flowchart relating to a fundus imaging method according to the fourth embodiment of the present invention. The difference from the fundus imaging method according to the second embodiment described with reference to FIG. 2 is that the focus adjustment process at step S5 and the fundus imaging at step S6 of the fundus imaging method according to the second embodiment. This is the point that the image sensor sensitivity adjustment step and the LED light amount adjustment step are inserted again between the steps.
Therefore, a different part from the fundus imaging method according to the second embodiment will be described, and a description of the common part will be omitted.
The fundus imaging method according to the fourth embodiment disclosed in FIG. 5 adjusts the imaging device sensitivity (step S2), further adjusts the LED light amount (step S3), and then performs fundus positioning and focus adjustment. Before performing fundus photography (step S8), the image sensor sensitivity is adjusted again and the LED light quantity is adjusted.
In the first place, because the fundus must be observed for a certain amount of time in the so-called observation of the fundus, which is so-called fundus positioning and focus adjustment, miosis occurs unless the intensity of visible light (visible light) is reduced. Therefore, there is a circumstance that the conventional infrared light source or near infrared light source has been used.
On the other hand, at the time of fundus photography, if the intensity of visible light is low, a clear fundus image cannot be obtained, and if the sensitivity of the image sensor is increased too much, there is a problem of noise. It becomes difficult. Further, as described above, the shutter speed cannot be relied on in relation to the speed of miosis.
Therefore, in the process related to fundus observation such as fundus positioning and focus adjustment, the amount of visible light is reduced or the sensitivity of the image sensor is increased, and in the process related to fundus imaging, within the time that can withstand the speed of miosis. Therefore, it is conceivable to reduce the sensitivity of the image sensor to such an extent that noise is not a problem while increasing the amount of visible light.

This is the fundus imaging method according to the fourth embodiment shown in FIG.
In the fifth embodiment, the adjustment of the imaging device sensitivity and the adjustment of the LED light amount related to the steps S4 and S5 related to fundus observation are divided into the adjustment related to the step S8 related to fundus imaging. By carrying out each independently, it is possible to clarify the merit of using one type of visible light LED light source as a light source for focusing a fundus image and as a light source for photographing. Of course, it is needless to say that the ease of control regarding the amount of light is large because it is a visible LED light source.
Furthermore, as described in the description of the second embodiment, the visible light LED light source may be turned off or may remain turned on after the fundus positioning step in step S4 and the focus adjustment in step S5. However, in the present embodiment, the light source for focusing and the light source for photographing are shared by one kind of visible light LED light source, and the adjustment of the imaging device sensitivity and the light amount of the visible light LED light source which are different in the process of using each light source are different. Since adjustment is performed, it is desirable to turn off the light after step S5 and then turn it on.
In the steps S6 and S7, it is not always necessary to make the adjustment by turning on the visible light LED, and the sensitivity and the light quantity can be set in advance, and the adjustment can be made by using the settings. Therefore, when the visible light LED is turned off after step S5, it may be turned on immediately before the fundus photographing process in step S8.
Of course, the above-described aperture adjustment may be performed. When the diaphragm adjustment process is used for the fundus oculi observation process (steps S4 and S5), it is between step S1 and step S2, between step S2 and step S3 in FIG. 5, or between step S3 and step S3. It can be included in any of the steps S4. Similarly, when used for the fundus photographing process, it can be performed between step S5 and step S6, between step S6 and step S7, or between step S7 and step S8.
By adjusting the aperture to open and close, it is possible to enhance or weaken exposure to the image sensor. By adjusting the exposure in this manner, it is possible to increase the number of imaging elements for fundus observation and fundus imaging, and thus it is possible to capture a clearer fundus image and improve image quality. It is possible to make it.

  In the fundus photographing system and the fundus photographing method according to the present embodiment described so far, a plurality of operations such as the light amount of the visible light LED, the sensitivity of the image sensor, the shutter speed (exposure time), and the aperture are combined. Since the fundus image of the optometry is taken, it is preferable that these operation parameters can be preset by the control device. Specifically, the amount of visible light LED can be preset by the light amount adjustment unit, the sensitivity of the image sensor by the sensitivity adjustment unit, the shutter speed by the shooting instruction unit, and the aperture by the aperture adjustment unit. These preset values may be stored in the database 22 so as to be readable from the respective adjustment units and photographing instruction units.

  As described above, the inventions described in claims 1 to 7 of the present invention can be used for ophthalmic examinations and diagnoses in general hospitals including general ophthalmic clinics, and can also be used for medical checkups. Furthermore, it can be applied not only to ophthalmology but also to medical examinations such as vascular diseases, and the use of systems and methods is easy and the accumulation of data with little variation expands the use to statistics and treatment methods. There is also a possibility.

DESCRIPTION OF SYMBOLS 1 ... Fundus imaging system 2 ... Eye to be examined 3 ... Pupil 4 ... Objective lens 5 ... Visible light LED 5a-5f ... Visible light LED 6 ... Mount 6a ... Light guide hole 7 ... Focusing lens 8 ... Imaging lens 9 ... Housing DESCRIPTION OF SYMBOLS 10 ... Imaging device 11 ... Irradiation light path 12 ... Reflection light path 13 ... Control apparatus 14 ... Light quantity adjustment part 15 ... Focus adjustment part 16 ... Sensitivity adjustment part 17 ... Shooting instruction | indication part 18 ... Image processing part 19 ... Display 20 ... Screen for focus confirmation DESCRIPTION OF SYMBOLS 21 ... Screen for imaging position confirmation 21a ... Enlarged area 22 ... Database 23 ... Image data 31 ... Fundus imaging system 32 ... Eye to be examined 33 ... Pupil 34 ... Objective lens 35 ... Visible light LED 36 ... Mount 37 ... Focusing lens 38 ... Connection Image lens 39 ... Case 40 ... Imaging device 41 ... Light path 42 ... Reflection path 43 ... Splitter

Claims (4)

A visible light emitting element light source that irradiates the fundus of the eye to be examined, an imaging element that receives a reflected light from the fundus of the visible light emitted from the visible light emitting element light source, and images the fundus image. A control unit having a focus adjustment unit for adjusting the focus of the fundus image to be driven by driving a focusing lens, an image processing unit for receiving and displaying data related to the fundus image, and processing performed by the control unit A non-mydriatic fundus photographing system having a display that receives the data and displays the fundus image, wherein the control device has a weak light amount that does not cause at least pupil reduction of the pupil of the subject eye during fundus observation A light amount adjustment unit that can adjust the light amount of the visible light emitting element light source, a sensitivity adjustment unit that adjusts the sensitivity of the imaging element, and a time required for miosis of the pupil with respect to the imaging element during fundus imaging Also And a photographing instruction unit for instructing to expose the Ku fixed time the reflected light to a predetermined, in that the visible light emitting element light source is a photographing light source with a focusing light source fundus image A characteristic non-mydriatic fundus imaging system. The visible light emitting element light source includes a plurality of light emitting elements arranged in a ring or a light emitting element formed in a ring, and reflected light from the fundus is formed in a plurality of light emitting elements arranged in a ring or in a ring. The non-mydriatic fundus imaging system according to claim 1, wherein a hole formed in the center of the light emitting element is an optical path. The visible light emitting element light source comprises at least one visible light emitting element, and the visible light emitted from the visible light emitting element light source irradiates the fundus of the subject's eye via a splitter or a perforated mirror, The non-mydriatic fundus imaging system according to claim 1, wherein the reflected light is received by the imaging device via the splitter or a perforated mirror. A step of setting an eye to be photographed for photographing a fundus image of the eye to be examined; a step of adjusting sensitivity of an image sensor for photographing the fundus image; and a visible light emitting element light source for photographing the fundus image Adjusting the amount of light to a weak light amount that does not cause at least the pupil of the eye to be examined, a step of irradiating the fundus with visible light from the visible light source, and a visible light from the visible light source Positioning the fundus of the subject's eye using light, adjusting the focus of the fundus image captured by the imaging device using visible light from the visible light emitting element light source, and the fundus image and adjusting the sensitivity of the image pickup device for photographing, the step of adjusting the amount of the visible light emitting element light source for photographing the fundus image, using said visible light from the visible light emitting element light source Mydriatic fundus photographing method characterized by comprising the steps of: a bottom image taken with exposure for a certain period of time the reflected light to a predetermined shorter than the time required to miosis of the pupil, the.