JPH07227380A - Eyeground camera - Google Patents

Abstract

PURPOSE:To adjust automatically the focus of an eye to be examined including astigmatism by providing a focusing means for detecting unfocusing and focusing from signals of a plurality of longitude directions of the image of an eyeground formed by a television camera. CONSTITUTION:A light bundle from an illumination light source 1 illuminates the eyeground Er of an eye E to be examined through a lens 2, a perforated mirror 3 and an objective lens 4 and a reflected light from the eyeground Er passes through a cross cylinder lens 5, a focus lens 6, a switch mirror 8, a relay lens 10 and a non-red color filter 11 to form an image on a television camera 12 and the image of the eyeground Er is displayed on a television monitor 13. In the case of focus adjustment, video signals on the horizontal and vertical lines P and V of the image Er of the eyeground are taken into a signal treatment controller 16 to detect the unfocusing. Then, the focus lens 6 and the cross cylinder lens 5 are respectively moved by driving means 15 and 14 to control it so as to make difference in horizontal and vertical focus positions small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus camera used in an ophthalmology clinic.

[0002]

2. Description of the Related Art Conventionally, as an autofocus fundus camera for an astigmatic eye, a method of projecting a plurality of focus targets and receiving them with a photoelectric sensor to focus is disclosed in, for example, Japanese Patent Laid-Open No. 3-7135. Proposed.

[0003]

However, the above-described conventional fundus camera has a problem that the structure is complicated, that it requires skill in handling, and is very complicated.

The object of the present invention is to solve the above-mentioned problems,
An object is to provide a fundus camera having a simple structure and capable of handling astigmatic eyes.

[0005]

A fundus camera according to the present invention for achieving the above object is a fundus camera for displaying a fundus image by a television camera, wherein blurring occurs from signals in the radial direction of the fundus image by the television camera. It is characterized by having a focusing means for detecting and focusing.

[0006]

The fundus camera having the above-mentioned structure captures the video signals on the horizontal and vertical lines of the fundus image projected on the television camera to detect the blur, and drives the focus lens and the cross cylinder lens so as to reduce the blur. Let it focus.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on the illustrated embodiments. FIG. 1 shows the configuration of this embodiment. A lens 2 and a perforated mirror 3 are arranged in front of the illumination light source 1, and an objective lens 4 is arranged on the eye E side in the reflection direction of the perforated mirror 3. There is. Further, a cross cylinder lens 5 composed of two identical cylindrical lenses, a focus lens 6, a lens 7, a switching mirror 8 and a film camera 9 are sequentially arranged on the observation system side in the opposite direction of the perforated mirror 3. Furthermore,
A relay lens 10, a red-color filter 11 for increasing the contrast of blood vessels, and a television camera 12 are arranged in the reflection direction of the switching mirror 8, and the output of the television camera 12 is connected to a television monitor 13. The cross cylinder lens 5 and the focus lens 6 are driving means 1 respectively.
4 and 15, the signal processing controller 16 is connected, and the signal processing controller 16 is connected to the television camera 12 and the television monitor 1.
Connected to 3.

The luminous flux from the illumination light source 1 illuminates the fundus Er of the eye E through the lens 2, the perforated mirror 3 and the objective lens 4. The reflected light from the fundus Er passes through the objective lens 4, the perforated mirror 3, the cross cylinder lens 5, the focus lens 6, the lens 7, the switching mirror 8, the relay lens 10 and the red-colorless filter 11, and forms an image on the television camera 12. The fundus image Er ′ is displayed on the television monitor 13. When observing the television monitor 13 and pressing a shutter button (not shown) when alignment and focus are achieved, the switching mirror 8
And the fundus image is recorded on the film camera 9.

At the time of focus adjustment, video signals on the horizontal line P and the vertical line V at the center of the fundus image Er 'are taken into the signal processing controller 16 and the blur is detected. In order to detect the blur, it is possible to use a method such that the sum of the second-order differential components becomes large, or a Fourier transform is performed to control the amount of high-frequency components. The focus lens 6 is moved by the driving unit 15 so as to reduce the blur, and the cross cylinder lens 5 is further moved by the driving unit 14, so that the signal processing controller 16 reduces the difference between the horizontal and vertical focus positions. Control.

Further, the two cross cylinder lenses 5 rotate in mutually opposite directions to generate astigmatism in the horizontal and vertical directions to correct the astigmatism generated in the anterior segment of the subject E. The reason why the video signal at the center of the screen is used is that unnecessary light flux such as corneal reflection easily enters in the peripheral portion.

2 and 3 show another embodiment of signal extraction from the fundus image Er 'on the television monitor 13. As shown in FIG.
In FIG. 2, the horizontal line S has three scanning lines, and the vertical line T has two. To use a signal on a vertical line, a signal corresponding to a time having a width of about one pixel is fetched at a predetermined position of each scanning line.

In addition to the horizontal and vertical lines L, FIG.
The signal on the 5 ° line R is captured. Since the astigmatic angle can be known if there is information of 3 meridians or more, the cross cylinder lens 5
Can be driven separately by two motors to change the astigmatic angle as well as the astigmatic degree, and each can be controlled to be corrected.

In a fundus camera not equipped with the cross cylinder lens 5, the focus lens 6 may be drive-controlled so as to match the average position of the horizontal and vertical focal points.

[0014]

As described above, the fundus camera according to the present invention detects the degree of blurring by using a plurality of signals in the meridian direction of the fundus image with a relatively simple structure and reduces the blurring. By focusing, it is possible to automatically focus the eye to be inspected, including astigmatism.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a present embodiment.

FIG. 2 is an explanatory diagram of signal extraction.

FIG. 3 is an explanatory diagram of signal extraction.

[Explanation of symbols]

 1 Illumination Light Source 5 Cross Cylinder Lens 6 Focus Lens 11 Contrast Filter 12 Television Camera 13 Television Monitor 14, 15 Driving Means 16 Signal Processing Controller

Claims (2)

[Claims] 1. A fundus camera for displaying a fundus image by a television camera, comprising a focusing means for detecting blur from signals of a plurality of radial lines of the fundus image by the television camera and focusing. camera. 2. A cylindrical lens provided at a conjugate position of the anterior segment,
The fundus camera according to claim 1, further comprising a control unit that controls the cylindrical lens based on a plurality of focus differences in a radial direction.