JPH11206715A - Photographing device for ophthalmology - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely provide the focused image of an eye to be examined by moving an optical system housing part to plural positions near an alignment completion position and instructing photographing at the positions. SOLUTION: An examiner operates a joy stick 3 while observing a front eye part image 28 projected on a screen 27. Then, an alignment luminescent point image formed by a CCD camera based on a visual mark projection optical system for XY alignment is put inside the circular mark of the screen 27 and the image is made clear. When the front eye part image projected on the screen 27 becomes a certain degree of visibility, a Z alignment detection circuit computes a Z direction alignment deviation amount. Based on the result, a control circuit commands the generation of pulse motor driving pulses. By the drive of the pulse motor, a cornea endothelium image is photographed. In such a manner, the focused image of the eye to be examined is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmic photographing apparatus for photographing an eye to be examined (for example, a corneal endothelial cell photographing apparatus,
A fundus camera, etc.), which includes an alignment detection system,
The present invention relates to an improvement in an ophthalmologic photographing apparatus that performs automatic alignment and automatic photographing based on a detection result of the alignment detection system.

[0002]

2. Description of the Related Art In a conventional ophthalmic photographing apparatus, an eye to be inspected and an apparatus main body are aligned, and photographing is performed when the alignment is completed. In addition, recently, when the joystick is used to move the main unit back and forth, left and right, and up and down to roughly align the main unit with the subject's eye, the delicate alignment is performed automatically and the shooting is automatically executed. There is also known an ophthalmic imaging apparatus of the type described below.

[0003]

However, when photographing at a high magnification, the tracking by the automatic alignment mechanism cannot catch up with the movement of the eye to be inspected, and an image of the eye to be inspected that is always in focus can be obtained. Was not limited.

The present invention has been made to solve this problem, and has as its object to reliably obtain a focused eye image.

[0005]

In order to achieve this object, the present invention provides an illumination optical system for illuminating an eye to be examined and an optical system housing for accommodating a photographing optical system for photographing the eye to be examined. Moving operation means for moving the optical system housing, alignment detecting means for detecting an alignment state between the optical system housing and the eye to be inspected, and moving operation means based on a detection result of the alignment detecting means And a control circuit for instructing the optical system to start photographing when the alignment detection unit detects that the optical system housing unit is at the alignment completion position. And the control circuit controls the moving operation unit so that the optical system housing unit is located at a plurality of positions near the alignment completion position. And summarized in that an instruction to execute the imaging at a plurality of positions. Thus, a focused eye image can be reliably obtained.

According to another aspect of the present invention, there is provided the image memory for storing the eye images photographed at the plurality of positions, and determining the sharpness of the plurality of eye images stored in the image memory. For this purpose, a sharpness judging means can be added. This makes it possible to automatically determine the most focused image.

[0007] Further, it is possible to further add reading means for reading out the eye image determined to have the highest definition from the image memory, and display means for displaying the read eye image. Thereby, the most focused image is automatically displayed from the plurality of eye images.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings, taking a corneal endothelial cell image photographing apparatus as an example.

(Optical System) As shown in FIG. 1, the optical system of the corneal endothelial cell photographing apparatus includes an anterior ocular segment observation optical system 20, an XY alignment index projection optical system 30, a fixation target optical system 31,
XY alignment detection optical system 40, photographing illumination optical system 5
0, a photographing optical system 60, a light beam projection optical system for Z alignment 70, a Z alignment detection optical system 80, and a control circuit 90.

<Anterior eye part observation optical system 20> The anterior eye part observation optical system 20 includes a plurality of infrared illumination light sources 21, a half mirror 22, an objective lens 23, a half mirror 24, It has a CCD camera 25 and a light shielding plate 29. When the infrared illumination light source 21 illuminates the anterior segment of the eye E, the reflected light reflected from the anterior segment of the eye E passes through the half mirror 22, the objective lens 23 and the half mirror 24 to the CCD camera 25. The image is guided and an anterior segment image is formed on the imaging surface of the CCD camera 25. The light shielding plate 29 is retracted from the optical path of the anterior ocular segment observation optical system 20 when observing the anterior ocular segment, and is inserted into the optical path when photographing corneal endothelial cells.

<XY alignment target projection optical system 30>
The XY alignment index projection optical system 30 includes a light source 32 for emitting infrared light, a condenser lens 33, an aperture stop 34, a pinhole plate 35 as an alignment index, a dichroic mirror 36, a projection lens 37, and a half mirror 22. Have.

The infrared light emitted from the light source 32 is condensed by a condenser lens 33, passes through an aperture stop 34, and is guided to a pinhole plate 35. The light beam that has passed through the pinhole plate 35 is reflected by the dichroic mirror 36,
The light is guided to the projection lens 37. The projection lens 37 converts the light beam passing through the pinhole plate 35 into a parallel light beam, and the parallel light beam is reflected by the half mirror 22 and projected on the cornea C as index light for XY direction alignment detection. A bright spot image is formed in the middle of the center of curvature.

<Fixation target optical system 31> Fixation target optical system 31
Is a fixation light source 38 that emits visible light, and a pinhole plate 39.
And a dichroic mirror 36, a projection lens 37, and a half mirror 2 which are common to the index projection optical system 30.
2 The fixation target light emitted from the fixation light source 38 passes through the pinhole plate 39 and the dichroic mirror 36, is converted into a parallel light flux by the projection lens 37, is reflected by the half mirror 22, and is guided to the eye E to be examined. I will The subject gazes at the fixation target light to fix his / her gaze.

<XY alignment detecting optical system 40> XY
The alignment detection optical system 40 has a half mirror 22, an objective lens 23, a half mirror 24, and an image receiving element 41 such as a PSD or an area CCD.

When the rough alignment by the joystick 3 is completed, the above-mentioned index light reflected at the vertex P of the cornea C is reflected by the half mirror 22 and the objective lens 2.
3. Image receiving element 41 reflected by half mirror 24
It is led to. The image receiving element 41 outputs a bright spot image formation position signal to the XY alignment detection circuit 42.

<Imaging illumination optical system 50> In FIG. 1B, the imaging illumination optical system 50 includes an imaging illumination light source 51 such as a xenon lamp, a condenser lens 52, a slit plate 53,
It has a dichroic mirror 54 for transmitting visible light and infrared reflection, an aperture stop 55, and an objective lens 56.

The visible light emitted from the photographing illumination light source 51 is condensed by a condenser lens 52 and guided to a slit plate 53, and the visible light passing through the slit plate 53 passes through a dichroic mirror 54 as slit light. The transmitted light is similarly guided to the aperture stop 55, and the cornea C is illuminated from an oblique direction by the objective lens 56.

<Shooting Optical System 60> The shooting optical system 60 includes an objective lens 61, a dichroic mirror 62 that reflects infrared light and transmits visible light, a mask 63, a mirror 64, and a relay lens 6.
5, a light shielding plate 66, a mirror 67, and a CCD camera 25.

A part of the slit light beam irradiated by the photographing illumination optical system 50 is reflected on the corneal endothelial cell surface. The light reflected by the corneal endothelial cell surface is reflected by the objective lens 61,
Dichroic mirror 62, mask 63, mirror 64,
CCD camera 2 via relay lens 65 and mirror 67
5 to form a corneal endothelial cell image on the CCD camera 25.

<Light Projection Optical System 70 for Z Alignment>
The light beam projection optical system 70 for Z alignment includes a light source 71 for emitting infrared light, a condenser lens 72, a slit plate 73,
It has a dichroic mirror 54, an aperture stop 55, and an objective lens 56. Then, the infrared light emitted from the light source 71 is converged by the condenser lens 72 while being slit.
Passes through to become slit light, and becomes a dichroic mirror 5
After being reflected by 4 and guided to the aperture stop 55, and transmitted through the aperture stop 55, the light is guided to the cornea C while being focused by the objective lens 56, and illuminates the cornea C.

<Z-Alignment Detection Optical System 80> The Z-alignment detection optical system (alignment detection means) 80
It has an objective lens 61, a dichroic mirror 62, and a linear sensor 81. Then, the reflected light of the cornea C of the slit light projected by the illumination optical system 80 for Z alignment detection is formed on the linear sensor 81 via the objective lens 61 and the dichroic mirror 62. The detection output of the linear sensor 81 is input to a Z alignment detection circuit 82.

(Drive Control System) << Fixed Base 1, Movable Base 2, Optical System Storage Unit 13 >> FIG. 2 is an external view of a corneal endothelial cell image photographing apparatus according to the present invention. In FIG. 2, reference numeral 1 denotes a fixed base incorporating a power supply and the like. A movable base 2 is mounted on the fixed base 1 so as to be movable in the front, rear, left and right directions (XZ directions) on the fixed base 1. Further, on the movable base 2, an optical system housing portion 13 for housing the above-described optical system is mounted.

<< Joystick 3 >> The movable base 2
The moving operation is performed by tilting the joystick 3 back and forth and left and right. In addition, the joystick 3 includes a rotating portion 3R that can rotate around an axis. The rotating operation of the rotating portion 3R is performed by the incremental encoder IE.
(Not shown).

<< XYZ Table 4 >> The optical system storage unit 13
X interposed between the movable base 2 and the optical system housing 13
The YZ table 4 (FIG. 3) moves the movable base 2 in the front-rear, left-right, and up-down directions (XYZ directions). The xyz table 4 includes a pulse motor 6, a support 7, a table 8, a support 8 ', a table 9, a support 9', a pulse motor 10, and a pulse motor 14, and the outputs of the above-described alignment detection circuits 42 and 82. This is for performing automatic alignment based on. The XYZ table 4 is housed inside the cover 5 together with the monitor device 27 (see FIG. 2).

The pulse motor 6 has a function of driving the column 7 in the vertical direction (Y direction), thereby moving the optical system housing 13 in the Y direction. In addition, the pulse motor 6
Is driven not only by a drive pulse generated based on the output of the XY alignment detection circuit 42 described above, but also by a drive pulse generated based on the detection output of the incremental encoder IE described above. I have.

A table 8 is fixed to the upper end of the column 7, and a column 8 ′ is fixed on the table 8. Further, a table 9 is arranged at the upper end of the column 8 '. A rail (not shown) extending in the left-right direction (X direction) is laid at the upper end of the column 8 ′, whereby the table 9 is movable in the X direction. The table 9 is driven by a pulse motor 10 disposed on the table 8, a pinion 11 attached to a rotation shaft of the pulse motor 10, and a rack 12 screwed to the pinion 11. The pulse motor 10 is driven by a drive pulse generated based on the output of the XY alignment detection circuit 42 described above.

Further, a column 9 'is fixed on the table 9, and an optical system housing 13 is mounted thereon. A rail (not shown) extending in the front-rear direction (z-direction) is laid at the upper end of the support 9 ′.
The optical system housing 13 is movable in the Z direction. The optical system storage unit 13 includes a pulse motor (moving operation means) 14 disposed on the table 9, a pinion 15 attached to a rotation shaft of the pulse motor 14, and the pinion 15.
Driven by a rack 16 which is screwed into the rack. The pulse motor 14 is driven by a drive pulse generated based on the output of the Z alignment detection circuit 82 described above.

<< Monitoring Device 27 >> As shown in FIG. 2, the monitoring device (display means) 27 is housed inside the cover 5 and displays an anterior eye image 28 and a corneal endothelial cell image captured by the CCD 25 on a screen 27a. To be displayed. In addition, the monitor device 27 has a circular mark 9 as an alignment reference mark.
5, 96 are displayed together with the anterior segment image. Circular mark 9
Reference numeral 5 denotes a mark indicating a position where automatic alignment by the XYZ table 4 is started. That is, when the joystick 3 is operated, the XY
When an alignment bright spot image is entered by the alignment target projection optical system 30, the XY alignment detection circuit 42 and Z
The XYZ table 4 becomes operable according to the detection output of the alignment detection circuit 82.

The circular mark 96 is a mark indicating that precise alignment in the front, rear, left and right directions (XY directions) has been completed. That is, as a result of the operation of the XYZ table 4, when the alignment bright spot image enters the circular mark 96, as soon as the alignment in the front-rear direction (Z direction) is completed,
Shooting becomes possible.

(Control / Processing System) << Control Circuit 90 >> The corneal endothelial cell image photographing apparatus according to the present invention has a control circuit 90 for controlling the operation of the entire apparatus as shown in FIG. .

That is, the control circuit 90 is connected to the CCD 25 and has a function of transferring a video signal obtained by the CCD 25 to the memory M and the monitor device 27.
The memory M has a capacity capable of storing a plurality of corneal endothelial cell images, and in association with the stored corneal endothelial cell images, the date and time of imaging, the identification number of the subject, and the number of cells per unit area. It has a function of storing data such as numbers.

The control circuit 90 includes an incremental encoder IE, an XY alignment detection circuit 42,
It has a function of transferring the detection output of the alignment detection circuit 82 to the drive pulse generation circuit P. The drive pulse generation circuit P generates the above-described drive pulses based on the input detection outputs, and outputs the drive pulses to the pulse motors 6, 10, and 14.
Has a function to send to.

Further, the control circuit 90 includes the following optical system:
When the XY alignment detection circuit 42 and the Z alignment detection circuit 82 detect the completion of the alignment, a function of outputting a light emission signal for causing the illumination light source 51 to emit light to the driver 51 ′ of the imaging light source 51.

Further, the control circuit 90 includes the light shielding plates 29 and 66
Has a function of sending a drive signal to solenoids 92 and 98 for inserting and removing the light into and from the optical path. The drive signal is generated when a power source (not shown) is turned on and when a light emission signal for causing the illumination light source 51 to emit light is transmitted.

[Operation of Embodiment] Next, the operation of the ophthalmologic photographing apparatus according to this embodiment will be described.

[Schematic Alignment] When a power source (not shown) is turned on, the light sources 21, 32, 38, and 71 are turned on. Further, the control circuit 90 controls the solenoid 97 to separate the light shielding plate 29 from the optical path of the anterior ocular segment observation optical system 20 and controls the solenoid 98 to insert the light shielding plate 66 into the optical path of the photographing optical system 60. Thereby, the anterior eye part image can be observed by the anterior eye part observation optical system 20.
The subject is caused to fixate the subject's eye by fixating the fixation target by the fixation target optical system 31. Then, the examiner observes the anterior eye image 28 reflected on the screen 27a, and displays the alignment bright spot image formed on the CCD camera 25 based on the XY alignment target projection optical system 30 in the circular mark 95 on the screen 27a. Operate the joystick 3 to enter the inside. In addition, the joystick 3 is operated so that the anterior eye image 28 shown on the screen 27a becomes clear to some extent.

[Automatic Alignment] Joystick 3
When the alignment bright spot image enters the circular mark 95 by the above operation, the corneal reflection light of the projection light beam from the XY alignment target projection optical system 30 is incident on the light receiving element 41. The XY alignment detection circuit 42 includes the light receiving element 4
The amount of misalignment in the X and Y directions is calculated based on the detection output of No. 1 and the calculation result is output to the control circuit 90.

On the other hand, when the image of the anterior segment on the screen 27a becomes clear to some extent, the light beam projection optical system 7 for Z alignment is used.
The corneal reflection light of the projection light flux from 0 is incident on the linear sensor 81. The Z alignment detection circuit 82 calculates the amount of misalignment in the Z direction based on the detection output of the linear sensor 81, and outputs the calculation result to the control circuit 90.

The control circuit 90 transfers the operation results of the XY alignment detection circuit 42 and the Z alignment detection circuit 82 to the drive pulse generation circuit P. Drive pulse generation circuit P
Are based on the result of this calculation,
A pulse for driving a required amount of the pulse No. 4 is generated, and this pulse is sent to the pulse motors 6, 10, and 14 to be driven. Thus, when the alignment bright spot image enters the circular mark 96 on the screen 27a, a corneal endothelial cell image can be captured.

[Photographing] When the alignment detecting circuits 42 and 82 detect that photographing is possible, the control circuit 90 controls the solenoid 97 to move the light shielding plate 29 to the optical path of the anterior ocular segment observation optical system 20. And solenoid 9
By controlling 8, the light shielding plate 66 is separated from the optical path of the photographing optical system 60. Thereafter, the control circuit 90 controls the pulse motor 14 via the drive pulse generation circuit P to move the optical system housing 13 backward by a predetermined distance from the alignment completion position. Here, the “child distance” is a distance that should be determined by the depth of focus of the photographing optical system 60, the brightness of the illumination light source 51, and other conditions that affect the quality of a photographed image. Here, the “predetermined distance” to be retracted is described as 0.5 mm.

When this retreat operation is completed, the control circuit 90
Outputs an emission signal for causing the imaging illumination light source 51 to emit light to the driver 51 ′ of the imaging illumination light source 51. As a result, the imaging illumination light source 51 emits light, and the illumination light is guided to the cornea C of the eye E by the imaging illumination optical system 50. Then, the reflected light reflected by the corneal endothelium of the eye to be examined is guided to the CCD 25 by the photographing optical system 60, whereby the CC
A corneal endothelial cell image is formed on the D camera 25. CCD
The corneal endothelial cell image formed at 25 is converted into image data by the control circuit 90, and the image data is stored in the memory M.

In this manner, when the photographing at the position retracted by 0.5 mm from the alignment completion position is completed, the control circuit 90 drives the pulse motor 14 via the drive pulse generation circuit P, and 13 is a distance obtained by dividing the above-mentioned “predetermined distance” by the number of times of photographing n (here, 0.5 /
n (mm)). In the present embodiment, the number of times of shooting is 1
Since the explanation is made assuming that there are no sheets, the distance to be advanced is 50
μm.

When the forward movement of 50 μm is completed, the control circuit 90 outputs a light emission signal for causing the photographing illumination light source 51 to emit light again to the driver 51 ′ of the photographing illumination light source 51. The obtained corneal endothelial cell image data is stored in the memory M.

Thereafter, the control circuit 90 repeats the 50 μm advancing operation and the photographing operation until corneal endothelial cell image data corresponding to ten corneal endothelial cell image photographs is obtained.

In this embodiment, 1. 1. After it is determined that the alignment is completed, the optical system housing unit 13 is retracted by a predetermined distance, and an image is taken at the retracted position. 2. The optical system housing 13 is advanced by a distance obtained by dividing the predetermined distance by the number of times of shooting, and shooting is performed at the advanced position. Although the photographing is performed in the procedure of repeating 2 as many times as necessary, the present invention is not limited to this, and the forward and backward may be interchanged. That is, 1. 1. After it is determined that the alignment is completed, the optical system housing unit 13 is moved forward by a predetermined distance, and an image is taken at a position where the optical system housing unit 13 is retracted. 2. The optical system storage unit 13 is retracted by a distance obtained by dividing the predetermined distance by the number of times of photographing, and photographing is performed at the retracted position. The shooting may be performed in such a procedure that 2 is repeated as many times as necessary. Further, in the above-described embodiment, the photographing is performed at either the rear position or the front position of the alignment completion position, but the photographing may be performed at both the front and rear positions.

[Determining Focus] In this manner, the memory M
When ten image data are stored in the control circuit 90,
Reads the image data into the memory M and determines the sharpness of the image, that is, the degree of focus.

Specifically, as schematically shown in FIG.
From the corneal endothelial cell image data Ai, it is sufficient to read out data stored at addresses D1, D2,..., Dk for storing an image corresponding to one horizontal scanning line, and analyze the data. When the read data is subjected to grayscale image processing by a known method, grayscale distribution data Wi as shown in FIG.
Is obtained for every ten image data. The density distribution data Wi is stored in the memory M in association with the analyzed corneal endothelial cell image data Ai.

When the focus determination has been completed for all the images in this way, the control circuit 90 determines, based on the grayscale distribution data Wi, an image having a large grayscale difference, that is, an image having a large grayscale difference.
The image data Ai determined to have the highest image sharpness is read from the memory, and the monitor device 27 displays a corneal endothelial cell image corresponding to the image data.

[0049]

As described above, according to the present invention, the control circuit controls the moving operation means so that the optical system housing portion is located at a plurality of positions near the alignment completion position. Since the execution of imaging is instructed at the plurality of positions, a focused eye image can be reliably obtained.

An image memory for storing the eye images photographed at the plurality of positions, and a sharpness determining means for determining the sharpness of the plurality of eye images stored in the image memory. When the image is added, the most in-focus image can be automatically determined.

Further, when reading means for reading out the eye image determined to have the highest definition from the image memory and display means for displaying the read eye image are further added, The most focused image is automatically displayed from the plurality of eye images.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an optical system of a corneal endothelial cell photographing apparatus according to the present invention.

FIG. 2 is an external perspective view of a corneal endothelial cell photographing apparatus including the optical system of FIG.

FIG. 3 is a side view showing a three-dimensional driving mechanism of the corneal endothelial cell photographing apparatus shown in FIG. 2;

FIG. 4 is an explanatory diagram of the control circuit shown in FIG.

FIG. 5 is an explanatory diagram of a corneal endothelial cell image photographed by the corneal endothelial cell photographing apparatus having the configuration shown in FIGS.

FIG. 6 is an explanatory diagram for a corneal endothelial cell image stored in the memory of FIG. 4 and focus determination.

FIG. 7 is an explanatory diagram of a light amount distribution on a predetermined line in FIG. 6;

[Explanation of symbols]

 Reference numeral 13: optical system storage unit 6, 10, 14 ... pulse motor (moving operation means) 20 ... anterior eye observation optical system 30 ... XY alignment index projection optical system 31 ... fixation Target optical system 40 ... XY alignment detection optical system 50 ... Imaging optical system 60 ... Photographing optical system 70 ... Z alignment light beam projection optical system 80 ... Z alignment detection optical system 90. ..Control circuit M ... Memory

Claims (3)

[Claims] An optical system storage unit for storing an illumination optical system for illuminating an eye to be examined and a photographing optical system for photographing the eye to be examined, and a moving operation means for moving the optical system storage unit An alignment detecting unit that detects an alignment state between the optical system housing unit and the eye to be inspected, and the moving operation unit based on a detection result of the alignment detecting unit, and the optical system housing unit moves to an alignment completed position. A control circuit for instructing the optical system to start photographing when it is detected by the alignment detecting means, wherein the control circuit includes a plurality of control circuits near the alignment completion position. And controlling the movement operation means so that the optical system housing portion is located at a position of the plurality of positions, and instructing execution of photographing at the plurality of positions. Ophthalmic imaging device. 2. An image memory for storing eye images to be inspected photographed at the plurality of positions, and a sharpness judging means for judging the sharpness of the plural eye images stored in the image memory. An ophthalmologic photographing apparatus according to claim 1. 3. The image processing apparatus according to claim 2, further comprising: reading means for reading out the eye image determined to have the highest definition from the image memory; and display means for displaying the read eye image. Ophthalmic imaging equipment.