JPH0513660B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fundus photographing device, and particularly to a fundus photographing device used for diagnosis in ophthalmology and neuropsychiatry, and for visual psychological experiments in psychology and image engineering. Regarding photography equipment.

[Prior Art and Problems to be Solved by the Invention] Conventionally, when photographing the fundus using a television camera or a film camera, the fundus is photographed using infrared light or visible light. It is difficult to obtain clear images with methods using infrared light, which requires irradiation with stronger infrared light. Furthermore, when using visible light, subjects feel dazzled and their pupils contract, so methods such as using mydriatic eye drops or photographing using flash light have been used.

Therefore, the main purpose of the present invention is to provide a fundus photographing device that minimizes the influence of weaker irradiation light on the subject's eyes and can capture clearer images. be.

[Means for Solving the Problem] The invention according to the first claim provides a fundus irradiation light source that irradiates light to the eyeball, a fundus photographing camera that photographs reflected light from the eyeball, and a fundus irradiation light source that irradiates light from the fundus irradiation light source. an optical system that forms an image from the fundus on a fundus photographing camera, an eye movement detection means that detects eye movement, and a servo control means that controls the optical system according to the detection output of the eye movement detection means. The device is configured to have the following features, and is capable of taking a stable image of the fundus while remaining stationary regardless of eye movement.

The invention according to claim 2 includes, in addition to the invention according to claim 1, image processing means for image processing the output image of the fundus photographing camera, and control of the image processing means according to the detection output of the eye movement detection means. and an address control means for performing this.

[Operation] The fundus photographing camera according to the present invention not only photographs the fundus, but also captures the subject's eye movement and feeds back the movement, so that the fundus photographing camera side can capture a still image regardless of the movement of the eyeball. Therefore, image processing such as integration and contour enhancement becomes easier, and a clearer fundus image can be taken.

[Embodiment of the Invention] FIG. 1 is a schematic block diagram of an embodiment of the invention. Referring to FIG. 1, a fundus irradiation light source 1 irradiates the fundus of an eye 3 with infrared light via an optical system 2.
The fundus image reflected from the fundus is input to the fundus photographing camera 4 via the same optical system 2. In order to detect eye movement, infrared light is irradiated from the eye movement detection infrared light source 6 to the cornea of the eye 3 via the optical system 7.

The reflected light from the corneal surface is input to an eye movement detection section 9 via an optical system 8 for eye movement detection. The eye movement detection section 9 detects the amount of eye movement and provides the detection output to the servo control section 10. The servo control unit 10 generates a control signal for driving the galvanometer 11 according to the detection signal, and drives the galvanometer 11. Galvanometer 1
1 controls the optical system 2.

By configuring as described above, it is possible to capture a still image of the fundus even if the subject's eyeballs move. The eye movement detection method is as follows:
There are various methods, and one of them, the corneal reflection method, will be explained later with reference to FIGS. 3 and 4.

FIG. 2 is a diagram showing a specific example of one embodiment of the present invention. Referring to FIG. 2, optical system 2 includes a half mirror 22, prisms 23 and 24, and a lens system 25. Light from the fundus irradiation light source 1 is reflected by a half mirror 22 and input to the fundus through prisms 23 and 24 and a lens system 25. Lens system 2
5 focuses the light from the fundus irradiation light source 1 on the fundus image, and a camera 4 for photographing the fundus image.
Focus on the top. The directions of the prisms 23 and 24 are controlled by galvanometers 111 and 112. For example, prism 23 is used to cancel the horizontal rotational component of eye movement, and prism 24 is used to cancel the vertical rotational component.

The infrared light source 6 for detecting eye movement is, for example, an infrared light source.
An LED is used, and a virtual image of an infrared LED spot is formed on the corneal surface via a lens system 27. The formed image is focused on an area sensor 83 such as a video camera via a mirror 81 and a lens system 82 that constitute the optical system 8. The eye movement detection section 9 detects horizontal and vertical two-dimensional eye movement from the image output from the area sensor 83 according to a principle described later, and generates a control signal for the servo control section 10.

The servo control unit 10 controls the galvanometers 111 and 112 according to instructions from the eye movement detection unit 9. In this way, the prisms 23 and 24 are driven so as to cancel the eyeball movement, and as a result, the incident light from the fundus irradiation light source 1 always enters the fundus surface from the front, and the fundus photographing camera 4 is driven to cancel the eyeball movement. It is possible to capture a still image of the fundus at all times.

In addition, eye movement detection methods include a method that irradiates the eye with weak infrared light and detects the difference in reflected light between the black eye and the white of the eye, and a method that detects the movement of a light spot imaged on the cornea. There are also various methods, such as having the subject wear a contact lens with a built-in coil and detecting eye movement from the electromotive force caused by the eye movement using light. Here, the principle using the corneal reflection method will be explained.

FIGS. 3 and 4 are diagrams for explaining the principle of detecting eye movement. In FIGS. 3 and 4, the virtual image 33 is formed on the crystalline lens 31 using the infrared LED 14. Since the rotation center O of the eyeball and the rotation center O' of the crystalline lens 31 are different, the virtual image 33 moves in parallel as the eyeball rotates. This amount of parallel movement 34 corresponds to the rotation angle of the eyeball, and an area sensor 83 such as a video camera shown in FIG. 2 is used to photograph an image 33' of the virtual image 33 that has been moved in parallel as shown in FIG. It is detected by

FIG. 5 is a schematic block diagram showing another embodiment of the invention. This embodiment is constructed in the same manner as in FIG. 1 described above except for the following points. That is,
The eyeball movement detecting section 9 detects horizontal and vertical two-dimensional eyeball movements, and a two-dimensional eyeball position signal is given to the address control section 12 . The address control section 12 uses the two-dimensional eyeball position signal to provide an address control signal to the image processing section 13 in order to remove image blur caused by eye movement included in the fundus photographed image. The image processing unit 13 has a memory (not shown), and stores images taken by the fundus camera 4 in the memory. Then, the image processing section 13
controls the memory in accordance with the address control signal given from the address control section 12 to remove image blur caused by eye movement included in the fundus photographed image. In this way, the output of the image processing unit 13 can always output a static fundus image even if eye movement occurs.

FIG. 6 is a diagram showing a more specific example of another embodiment of the present invention. The optical system shown in Fig. 6 is
The detection output of the eye movement detection section 9 is given to the address control section 12, and the address control signal from the address control section 12 is given to the image processing section 13. Similarly, the output of the image processing unit 13 always outputs a stationary fundus image even if eye movement occurs.

[Effects of the Invention] As described above, according to the present invention, when photographing the fundus of the eye, the eye movement of the subject is captured and the movement is fed back, thereby creating a still image of the fundus despite the movement of the eyeball. It is possible to obtain an extremely useful experimental device for medical applications such as ophthalmology and visual psychology fields such as elucidation of neural circuits in the retina.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of one embodiment of the present invention. FIG. 2 is a diagram showing a more specific configuration of an embodiment of the present invention. FIGS. 3 and 4 are diagrams for explaining an example of eye movement detection.
FIG. 5 is a schematic block diagram showing another embodiment of the invention. FIG. 6 is a diagram showing a more specific example of another embodiment of the present invention. In the figure, 1 is a fundus irradiation light source, 2, 7, and 8 are optical systems, 4 is a fundus photographing camera, 6 is an infrared light source for eye movement detection, 9 is an eye movement detection section, 10 is a servo control section, and 11 is a galvanometer. , 12 is an address control section, and 13 is an image processing section.

Claims (1)

[Scope of Claims] 1. A fundus irradiation light source that irradiates light to the eyeball, a fundus photographing camera that photographs reflected light from the eyeball, and a fundus photographing camera that images the light from the fundus irradiation light source on the fundus. an optical system for forming an image on the fundus photographing camera; an eye movement detecting means for detecting the movement of the eyeball; and a servo control means for controlling the optical system according to a detection output of the eye movement detecting means. What is claimed is: 1. A fundus photographing device, which is capable of capturing a stable fundus image by standing still regardless of eye movement. 2. A fundus irradiation light source that irradiates light onto the eyeball, a fundus photography camera that photographs reflected light from the eyeball, and a fundus photography camera that images the light from the fundus irradiation light source on the fundus and captures the image from the fundus. an optical system for forming an image on the fundus; an image processing means for processing an output image of the fundus photographing camera; an eye movement detection means for detecting the movement of the eyeball; A fundus photographing device comprising an address control means for controlling an image processing means, and capable of photographing a stable fundus image while remaining stationary despite eyeball movement.