JPH11188006A - Ophthalmic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bring an eyeground into focus with autofocusing operation for a apatient with cataract and so on. SOLUTION: The ophthalmic device is generally formed to irradiate the eyeground Er of the subject eye E with light and take an image of it with CCD 35, then based on the pickup image from CCD 35, to do autofocus control with contrast system. The device has a memory 42 which is stored the data of pattern image of eyeground image and compares the pickup image on CCD 35 with the data of pattern image to determine whether the image on the CCD 35 is the eyeground image of the subject eye E or not. If it is not the image of is the eyeground image of the subject eye E, AF driving circuit 41 shifts the focus lens 31 along the light axis and dose a driving control to be the pickup image on CCD 35 is the eyeground image of the subject eye.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic apparatus capable of observing a fundus image by focusing the image by autofocus.

[0002]

2. Description of the Related Art Generally, in an ophthalmologic apparatus that focuses a fundus image by auto-focusing, an irradiating optical system that irradiates light to the fundus of the eye to be inspected, and a photographing method that captures a fundus image of the eye from reflected light at the fundus And an optical system. Then, based on captured image information from an imaging element such as a CCD provided in the imaging optical system, the position of the focus lens is controlled by a contrast method to perform autofocus.

[0003]

However, in the above-mentioned prior art, light is radiated to the subject's eye and autofocus control is performed based on the reflected light. However, there is a drawback that focusing on the fundus cannot be performed smoothly. That is, since a patient with a disease such as cataract has a portion that strongly reflects light in front of the fundus, when the eye to be examined is irradiated with light, the above-mentioned portion is in focus. Can not be matched.

[0004] It is an object of the present invention to provide an ophthalmologic apparatus which can focus on the fundus of an eye by an auto-focus operation even for a patient having a disease such as cataract.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a fundus image of a subject's eye is illuminated with light by irradiating the fundus of the subject's eye with an image pickup device. In an ophthalmologic apparatus that performs autofocus control by a contrast method based on a captured image from an imaging element, a storage unit in which data of a pattern image having a fundus image is stored in advance, and the data of the captured image and the data of the pattern image. By comparing the captured image, the determination unit that determines whether the captured image is the fundus image of the eye to be inspected, and when it is determined that the captured image is not the fundus image of the eye to be inspected, And control means for driving and controlling a focus lens so that a captured image becomes a fundus image of the eye to be inspected.

According to a second aspect of the present invention, in the first aspect, the comparing means compares the data of the picked-up image and the data of the pattern image with the amount of light reflected from the subject's eye. Data is detected, and when there is a portion where the amount of light is larger than the characteristic portion of the fundus, it is determined that the captured image is not the fundus image of the eye to be examined.

According to a third aspect of the present invention, the fundus of the eye to be inspected is irradiated with light, and an image of the fundus of the eye to be inspected is picked up by an image sensor, and an autofocus is performed by a contrast method based on the image picked up by the image sensor. In the ophthalmic apparatus performing the control, the presence or absence of blood vessels in the captured image is detected.If there is a blood vessel, the captured image is determined to be a fundus image of the eye to be examined. A determination unit that determines that the image is not the fundus image of the eye to be inspected, and when the determination unit determines that the captured image is not the fundus image of the eye to be inspected,
Control means for controlling driving of a focus lens so that a captured image on the image sensor becomes a fundus image of the eye to be inspected.

According to a fourth aspect of the present invention, in the third aspect, the determination means obtains an image density level around the nipple of the subject's eye in the picked-up image. It is characterized in that the presence or absence of a blood vessel is detected by detecting whether or not there is a blood vessel.

According to a fifth aspect of the present invention, in the third aspect, when the illuminating unit irradiates the fundus of the subject's eye with light through a non-red filter, the fundus image of the subject's eye in the captured image is obtained. The presence or absence of a blood vessel is detected by detecting whether or not there is a black portion.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of the ophthalmologic apparatus of the present invention. In FIG. 1, reference numeral 1 denotes a base of an ophthalmologic apparatus, and columns 2 and 2 are mounted on left and right front ends of the base 1. A chin rest 3 is bridged between the intermediate portions of the columns 2, 2, and a forehead rest 4 is bridged between the upper ends of the columns 2, 2.

A gantry 5 is mounted on the base 1. The gantry 5 is provided with a joystick 6, and by operating the joystick 6, the gantry 5 can be moved back and forth, left and right. An ophthalmologic apparatus main body 9 is attached to the gantry 5 via arms 7 and 8. A lens barrel 9 having a built-in objective lens of an optical system
a is provided so as to protrude, and a 35 mm camera 10 is mounted on the opposite surface. An operation switch 11 for performing a right eye / left eye switching operation is mounted on the gantry 5.

Next, the internal configuration of the ophthalmologic apparatus main body 9 will be described with reference to FIG. An illumination optical system 20 and an imaging optical system 30 are provided in the ophthalmologic apparatus main body 9. The illumination optical system 20 includes a concave mirror 21 and a halogen lamp 2 for illumination.
2, relay lens 23, xenon lamp 24 for photographing,
It is roughly composed of a condenser lens 25, a reflection mirror 26, and a relay lens 27, and is configured so that illumination light is guided to the fundus Er of the eye E through a perforated mirror 28 and an objective lens 29. The photographing optical system 30 includes the objective lens 2
9, a perforated mirror 28, a focus lens 31, a quick return mirror 32, a relay lens 33, a reflection mirror 34, and a CCD 35. The focus lens 31 is movable between a position indicated by a solid line and a position indicated by a two-dot chain line.

The ophthalmologic apparatus main body 9 includes an image comparison circuit 40,
An AF (auto focus) drive circuit 41 and a memory 42 are built in. In FIG. 2, reference numeral 43 denotes the CCD 3
A television monitor 44 connected to 5 is a film built in the 35 mm camera. E1 and E2 denote exciter filters and their dummy filters which are removably provided in the illumination optical system 20, and B1 and B2 denote barrier filters and their dummy filters which are removably provided in the imaging optical system 30.

In the above configuration, the illumination light guided to the fundus Er of the eye E to be inspected by the illumination optical system 20 is reflected by the fundus Er to become an image forming light beam, guided to the photographing optical system 30, and An image is formed once in the rear, and a perforated mirror 28 is formed.
Is formed on the film 44 by the focus lens 31 through the hole 28a. Quick return mirror 3
Numeral 2 is horizontal as shown by the solid line in the figure when photographing the fundus, but is inclined as shown by the broken line in the figure when observing the fundus.

At the time of fundus observation, the image forming light beam from the fundus Er is reflected by the quick return mirror 32 and guided to the CCD 35 via the relay lens 33 and the reflection mirror 34. At this time, the image is formed on the CCD 35 by the relay lens 33. Is done. The fundus image of the eye E formed on the CCD 35 is a captured image, and data of the captured image is transmitted to the image comparison circuit 40 and the television monitor 43. The television monitor 43 displays the captured image. The image comparison circuit 40 compares the data of the captured image transmitted from the CCD 35 with the data of the pattern image having the fundus image stored in the memory 43 in advance, and the captured image is the fundus image of the eye E to be inspected. It is determined whether or not.

Here, a method of determining whether or not the captured image is the fundus image of the eye E to be inspected will be described. FIG.
FIG. 5 shows a change in light amount when a central portion of the nipple 50 is scanned with respect to a captured image of the fundus image formed on the CD 35. As can be seen, if the patient does not have a disease such as a cataract, the amount of light at the nipple 50 will be greatest.

However, when the patient has a disease such as cataract, as shown in FIG.
Because of the presence of 1, the reflected light amount (the hatched portion in the figure) at the portion 51 becomes the largest. In normal auto focus control, the focus is on the portion where the amount of reflected light is the largest. Therefore, in the case of FIG. 4, the captured image displayed on the television monitor 43 has the portion 51 clear and the nipple 5
0, ie, the fundus becomes unclear.

In this embodiment, the data of the light amount as shown in FIG. 3 is stored in the memory 43 in advance as the data of the pattern image, and when the data of the picked-up image is transmitted from the CCD 35, The comparison circuit 40 detects light amount data from the data of the captured image, and when there is a portion 51 where the light amount is larger than the portion of the nipple 50 as shown in FIG. It is determined that the image is not the fundus image of the optometry.

FIG. 5 shows a change in the amount of light when the center of the nipple 52 is scanned with respect to the image of the fundus image formed on the CCD 35 when the patient has a disease such as cataract in the right eye. Things. Also in this case, similarly to the case of FIG. 3, the light amount data is stored in the memory 43 in advance as pattern image data. And CCD35
When the data of the captured image is transmitted from the CPU, the data of the light amount is detected from the data of the captured image, and when there is a portion 53 where the magnitude of the light amount is larger than the portion of the nipple 52, the captured image on the CCD 35 is detected. Is determined not to be the fundus image of the eye to be examined.

The result of the determination is sent to the AF driving circuit 41.
Is sent to the AF drive circuit 41 so that the captured image on the CCD 35 becomes a fundus image of the eye to be inspected.
Is moved in a predetermined direction along the optical axis.

At the start of the optometry, the focus lens 31 is set at a position distant from the eye E (the position shown by the broken line in FIG. 2). (For example, a position indicated by a solid line in FIG. 2). At this time, when it is determined that the captured image on the CCD 35 is not the fundus image of the eye to be inspected, the movement of the focus lens 31 is performed a plurality of times. That is, in the first focusing, the focus lens 31 moves leftward from the position indicated by the broken line in FIG.
The focus lens 31 is further focused to the left and the nipples 50 and 52 are focused by the second and subsequent focusing operations.

When an optometry is performed, blood vessels should be observed only in the fundus of the eye to be inspected. Therefore, by detecting the presence or absence of blood vessels in the captured image on the CCD 35, the captured image can be detected. It can be determined whether or not the image is a fundus image. In this case, as a method of detecting the presence or absence of a blood vessel in the captured image, there are a method of obtaining from the image density level around the nipple and a method of using a non-red filter.

According to the method of obtaining from the image density level around the nipple, as shown in FIG. 6, a radius (circular locus indicated by a broken line in the figure) corresponding to, for example, 1.5 times the nipple 60 is measured from the center position 60a of the nipple 60. , And changes in the image density level around the nipple 60 are observed. If the captured image is a fundus image of the eye to be inspected, the blood vessel images 61 to 64 around the nipple 60 should be clearly captured. Therefore, the image density levels correspond to the blood vessel images 61 to 64 as shown in FIG. The portions 61a to 64a showing the characteristics show sudden changes.

Therefore, if there is a portion where the image density level around the nipple changes abruptly as shown in FIG. 7, it can be determined that the captured image including the nipple is a fundus image of the eye to be examined. Conversely, if there is no sharp change in the image density level around the nipple, it can be determined that the captured image including the nipple is not the fundus image of the eye to be examined.

In the method using a non-red filter,
A non-red filter (also referred to as a green filter) is inserted into an illumination optical system that irradiates light to the fundus of the subject's eye, and a fundus image of the subject's eye in a captured image at that time is observed. As the non-red filter, there is, for example, a color glass filter G-533 made by HOYA. In this filter, the distribution of transmittance is set as shown in FIG. When such a non-red filter is inserted into the illumination optical system, the fundus of the eye to be inspected is irradiated with light containing almost no red, and if there is a blood vessel, the portion appears black.

Therefore, if the captured image has a portion that looks black when the non-red filter is inserted into the illumination optical system, it can be determined that the captured image is a fundus image of the eye to be examined. Conversely, if there is no black portion in the captured image, it can be determined that the captured image is not a fundus image of the subject's eye. FIG. 9 shows the image density level around the nipple using the non-red filter.

Next, FIG. 10 shows a magnified view of the portion of the nipple 50 or 52 in the captured image on the CCD 35. The present embodiment is characterized in that the focus area 54 of a captured image can be set to an arbitrary size and an arbitrary position. When the magnification is changed, the characteristic region (for example, the nipple) of the fundus image occupies most of the visual field. However, if the focus area 54 of the captured image can be set to an arbitrary size as shown in the figure, the eye to be inspected is changed. It is convenient for observation. Also, the focus area 54 of the captured image
Can be set to an arbitrary position as shown in the figure, even if the alignment is slightly shifted, if there is a characteristic portion of the fundus image in the screen, the focus area 54 is moved to an arbitrary position without performing alignment again. This enables autofocus control.

In the present embodiment, the operation of the operation switch 11 shown in FIG.
, The pattern image of the fundus image of the right eye or the pattern image of the fundus image of the left eye is selectively taken into the image comparison circuit 40. In this way, for example, when two left peaks appear in the light quantity data as shown in FIG. 4 when the patient's left eye is examined, the nipple 50 is originally located on the left side of the figure. Can be immediately determined not to be due to the nipple 50. In addition, when examining the patient's right eye,
When two peaks appear in the light amount data as shown in FIG. 5, the nipple 52 is originally located on the right side of the figure, so the right peak is due to the nipple 52 and the left peak is due to the nipple 52. If not, it can be determined immediately.

Next, an operation procedure in the ophthalmologic apparatus having the above configuration will be described with reference to FIG. In FIG. 11, the gantry 5 is moved back and forth and left and right by operating the joystick 6 to detect the subject's eye (step 100).
The alignment is adjusted (step 101), and the lens barrel 9 is adjusted.
a is set to the initial position (step 102). At this time, the focus lens 31 is set at the position indicated by the broken line in FIG. Next, auto focus is started (step 103), and when the focus lens 31 moves along the optical axis and a focused image is formed on the CCD 35, the auto focus ends (step 10).
5).

As described above, the data of the picked-up image on the CCD 35 is transmitted to the image comparing circuit 40, and the light amount data of the picked-up image is stored in the memory 42 in the image comparing circuit 40. It is detected whether or not the pattern matches, that is, whether or not the size of the light amount data is the largest at the nipple portion (step 105). If the nipple is the largest, CCD3
Since the captured image on 5 is the fundus image of the eye to be examined, the autofocus control ends. However, if the nipple region is not the largest, the focus lens 31 moves further along the optical axis and the autofocus starts again. (Step 10
6) Go to step 104. And step 10
6, the processing operations of step 104 and step 105 are as follows:
This process is repeated until the light amount data of the captured image matches the data of the pattern image in the memory 42.

[0031]

As described above, according to the present invention,
Even if there is a part that reflects light other than the characteristic part of the fundus, it will not be focused on that part, even for patients with cataracts and other diseases, focus on the fundus by operating the autofocus It becomes possible.

[Brief description of the drawings]

FIG. 1 is an external perspective view of an ophthalmologic apparatus according to the present invention.

FIG. 2 is an internal configuration diagram of an ophthalmologic apparatus main body.

FIG. 3 is a diagram showing a light amount distribution in a fundus of a left eye.

FIG. 4 is a diagram showing a light amount distribution in a fundus of a left eye of a patient such as a cataract.

FIG. 5 is a diagram showing a light amount distribution in a fundus of a right eye of a patient such as a cataract.

FIG. 6 is a diagram showing a method of obtaining the presence or absence of a blood vessel from the image density level around the nipple.

FIG. 7 is a diagram illustrating an example of a change in an image density level.

FIG. 8 is a diagram illustrating an example of transmittance characteristics of a non-red filter.

FIG. 9 is a diagram showing a change in image density level when a non-red filter is used.

FIG. 10 is a diagram when a characteristic portion of the fundus is viewed at an enlarged magnification.

FIG. 11 is a flowchart showing an operation procedure in the ophthalmologic apparatus of the present invention.

[Explanation of symbols]

 9 Ophthalmic apparatus main body 9a Lens barrel 31 Focus lens 11 Operation switch 35 CCD 40 Image comparison circuit 41 AF drive circuit 42 Memory 50, 52, 60 Nipple 51, 53 Parts other than papilla 61 to 64 Blood vessels

Claims (5)

[Claims] 1. An ophthalmologic apparatus that irradiates a fundus of an eye to be examined with a light to capture a fundus image of the eye to be examined by an image sensor, and performs autofocus control in a contrast method based on an image captured from the image sensor. A storage unit in which data of a pattern image having a fundus image is stored in advance, and comparing the data of the captured image with the data of the pattern image, determines whether the captured image is a fundus image of the eye to be inspected. Determining means for determining, and, when it is determined that the captured image is not a fundus image of the eye to be inspected, control means for driving and controlling a focus lens so that the captured image on the image sensor becomes a fundus image of the eye to be inspected. ,
An ophthalmologic apparatus comprising: 2. The ophthalmologic apparatus according to claim 1, wherein the determination unit compares data of the amount of light reflected from the subject's eye when comparing the data of the captured image with the data of the pattern image. An ophthalmologic apparatus characterized in that, when there is a part where the magnitude of the light amount is larger than the characteristic part of the fundus, the captured image is determined not to be the fundus image of the eye to be examined. 3. An ophthalmologic apparatus that irradiates a fundus of a subject's eye with light to capture a fundus image of the subject's eye with an image sensor and performs autofocus control by a contrast method based on a captured image from the image sensor. Detecting the presence or absence of blood vessels in the captured image, if the presence of blood vessels, the captured image is determined to be a fundus image of the eye to be examined,
When there is no blood vessel, the determination unit determines that the captured image is not the fundus image of the eye to be inspected, and when the determination unit determines that the captured image is not the fundus image of the eye to be inspected, An ophthalmologic apparatus, comprising: control means for driving and controlling a focus lens such that a captured image is a fundus image of the eye to be inspected. 4. The ophthalmologic apparatus according to claim 3, wherein the determination unit obtains an image density level around the nipple of the subject's eye in the captured image, and determines whether there is a location where the image density level changes rapidly. An ophthalmologic apparatus, wherein the presence or absence of a blood vessel is detected by detecting the presence or absence of a blood vessel. 5. The ophthalmologic apparatus according to claim 3, wherein the determining unit irradiates the fundus of the subject's eye with light via a non-red filter to form a black fundus image of the subject's eye in the captured image. An ophthalmologic apparatus for detecting the presence or absence of a blood vessel by detecting whether or not there is a portion.