JP2607216B2 - Centering device in eyeball imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television image pickup apparatus for enlarging and displaying an eyeball, particularly an endothelial cell of the cornea, and more specifically, a center axis of the image pickup apparatus coincides with the center of the eyeball. The invention relates to a centering device to be used.

[0002]

2. Description of the Related Art The endothelial cells of the cornea are extremely dark and have low contrast. Therefore, when observed or photographed under normal illumination, the cornea endothelial cells are obstructed by the corneal surface reflected light that is about 20 times as strong as that. I can't catch this. As shown in FIG. 7, when the cornea 93 is illuminated from an oblique direction by the slit-shaped illumination light 92 passed through the narrow slit 91, the image light beam 95 of the corneal endothelium 94 and the reflected light beam 97 of the surface 96 can be separated. it can.

FIG. 8 shows a schematic configuration of an apparatus for imaging corneal endothelial cells using the above-mentioned slit-shaped illumination light.
Reference numeral 01 denotes a slit-shaped infrared light source.
Is connected to a power supply 103, 104 is a slit-shaped strobe light source connected to a power supply device 105, and 106 is a television camera. The light sources 101 and 104 and the television camera 106 move manually or automatically with respect to the eyeball for focusing.

First, when the switch 102 is closed and an image is taken while illuminating with infrared light, the camera 106 captures the surface reflected light 97 and the image light beam 95 shown in FIG. Then, a video signal including a surface reflection signal R and a corneal endothelial cell image signal I is generated. H is a horizontal synchronizing signal. Here, when the distance between the camera 106 and the eyeball changes,
The signals R and I are kept at a substantially constant time interval t,
It moves as shown by the arrow with respect to the synchronization signal H. In addition, since there is no great individual difference in the thickness of the cornea, the interval t is substantially constant unless a contact lens is used. Then, when the corneal endothelial image signal I comes to the position of the time T with respect to the synchronization signal H as shown in FIG. 5B, the television camera 106 is brought into a state in which the corneal endothelial cells 94 are in focus.

In FIG. 8, a surface reflection image signal R is extracted from a video signal of a camera 106 in a wave height discrimination circuit 107, shaped, and sent to a gate circuit 108. The gate circuit 108 includes the timed circuit 1 as shown in FIG.
At 09, the gate signal is opened by a gate wave generated at a position delayed by (T−t) time from the synchronization signal H, so that when the above-mentioned crest-discriminated and shaped surface reflection image signal matches this, the gate circuit 108 outputs Occurs. At this time, the television camera 106 is focused on the corneal endothelial cell 94.

The output of gate circuit 108 triggers strobe power supply 105 to cause strobe light source 104 to emit light. The video signal thus captured is transmitted to the gate circuit 1
The image data is temporarily stored in the frame memory 101 through 10 and displayed on the image display 112. The gate circuit 110
Is opened by the frame control circuit 113 for one image period following the flash emission.

[0007]

If the center axis of the apparatus does not match the center axis of the eyeball even if the operation of focusing the corneal endothelial cell on the television camera as described above does not match, Good focus cannot be achieved throughout. Accordingly, it is an object of the present invention to align the central axis of the device with the central axis of the eyeball.

[0008]

According to the present invention, in the above-described eyeball imaging apparatus, spot light modulated at a constant frequency from the center axis direction of the apparatus located between the illumination optical path and the imaging optical path is applied to the eyeball. The image is projected, and the irradiated area is simultaneously imaged by a television camera. Then, the imaging signal is synchronously detected at the frequency described above, and only the reflected light signal of the spot light on the corneal surface is extracted .
Corresponding to a predetermined section in the television image displaying the imaging signal.
Light reflected through the gate
Signal to come to a predetermined position in the compartment, automatically move adjust the overall system in a direction orthogonal to the central axis.

[0009]

The examiner adjusts the apparatus to a low magnification and constantly adjusts the center of the eyeball image to the center of the screen while watching the television screen. However, even if the center of the eyeball comes to the center of the screen, the imaging apparatus does not always face the eyeball, and often captures the center of the eyeball from an oblique direction.
In such a case, according to the present invention, even if the center of the eyeball is located at the center of the screen, the spot irradiated by the spotlight appears at a position deviated therefrom.

Since the spot light is modulated at a predetermined frequency in advance, only the reflected light signal of the spot light from the eyeball can be extracted from the image signal by synchronously detecting the image signal . This reflected light signal is
Manually position the device so that it is within the predetermined area
Adjusting the reflected light signal automatically with is contrasted with horizontal, vertical synchronizing signal, which is to come to the center of the screen, moved and adjusted in a direction perpendicular to the central axis of the device is performed.

If a state in which the spot irradiated by the spot light coincides with the center of the eyeball at the center of the screen is obtained, the apparatus is switched to a high magnification, and the apparatus is automatically moved by moving the apparatus in the direction of the central axis by the automatic focusing circuit. Then, the corneal endothelial cells are imaged. Thereby, a clear cell image can be captured over the entire field of view.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG.
In the X direction perpendicular to the paper surface and the Y direction which is the vertical direction of the paper surface, and in the Z direction which is the direction of the central axis 2, there are three directions:
They are moved by the driving mechanisms 3, 4, and 5, respectively.
Reference numeral 6 denotes an eyeball located on the central axis 2, and reference numeral 7 denotes the imaging device 1.
2 shows an infrared light source for iris illumination provided on both sides (in front of and behind the paper).

In the image pickup device 1, a strobe flash tube 12, an illumination optical axis 11 extending from below the central axis 2 toward the eyeball 6,
Visible light is irradiated by the optical path of the condenser lens 13, the infrared removal filter 14, the translucent mirror 15, the slit 16, and the projection lens 17, and the light source 18 and the condenser lens 1
9. The infrared light path composed of the infrared filter 20 is a translucent mirror 1
5 joins the optical path. In addition, slit 1
6 corresponds to the slit 91 in FIG.

Above the central axis 2, on an imaging optical axis 21 passing through the eyeball 6, an imaging lens 22, an infrared filter 24 located at one half of an imaging surface 23, and a variable magnification imaging lens system 25 And an imaging light receiving surface 26 are arranged, and a video signal is obtained from the light receiving surface 26.

A modulation power supply 44 shown in FIG.
Light source 31 flickering at high speed and condenser lens 3
2, an infrared filter 33, a pinhole 34, a translucent mirror 35, and a focusing lens 36, and irradiate the eyeball 6 with infrared spot light. The fixation target light generated by the red light source 37, the condenser lens 38, and the pinhole 39 is guided on the central axis 2 by the reflecting mirror 40 and the translucent mirror 35.

In FIG. 2, a video signal obtained by the image pickup apparatus 1 shown in FIG. 1 is displayed by a receiver 43 via switches 41 and 42. The video signal is synchronously detected by the synchronous detector 45 at the modulation period of the modulation power supply 44. The light source 31 of the above-mentioned infrared spot light is lit by the modulation power supply 44, so that the synchronous detector 4
In FIG. 5, only the reflected image signal S of the infrared spot light on the eyeball surface is extracted from the video signal as shown in FIGS. 3 (a) and 4 (a).

FIG. 3A shows a horizontal scanning line signal passing through the synchronous detector 45, where H is a horizontal synchronizing signal, and S is a reflected image signal of infrared spot light. This horizontal scanning line signal is supplied to the gate 46. As shown in FIG. 3 (b), gate control waves persist for T ₂ hours in the control circuit 48 after the horizontal synchronization signal H is T ₁ times delayed by the delay circuit 47 is made, the gate 46 is opened by this . Thus the reflected image signal S of the infrared spot light, when arriving in the T ₂ hours, the gate 46 as shown in FIG. 3 (c) is passed through it.

When the reflected image signal S appears at the output of the gate 46, the X-direction position control circuit 49 operates to drive the X-direction drive mechanism 3 shown in FIG. adjusting a reflection image signal S is controlled to come to the position of the center of the time zone T _2, i.e. from the synchronizing signal _{H (T 1 + T 2/} 2).

Similarly, FIG. 4A shows a vertical scanning signal obtained by the synchronous detector 45, V is a vertical synchronizing signal, and S is a reflected image signal of infrared spot light. The vertical scanning signal is supplied to the gate 50. Delay circuit 51 and control circuit 52
In the gate control waves persist for T ₄ hours delayed ₃ hours T from the vertical synchronizing signal V as shown in FIG. 4 (b) is made, the gate 50 is opened by this. Therefore, the reflected image signal S of the infrared spot light is generated during this time period T ₄
When it arrives inside, it passes through it as shown in FIG.

When the reflected image signal S appears at the output of the gate 50, the Y-direction position control circuit 53 operates to drive the Y-direction drive mechanism 4 of the imaging device 1 to adjust the vertical position of the imaging device 1. as a result, the reflected image signal is controlled to come to the position of the center of the time zone T _4, that is, from the vertical synchronizing signal _{V (T 3 + T 4/} 2).

The gate control waves of the control circuits 48 and 52 are supplied to an area display circuit 54 to generate a signal for displaying an area defined by the gates 46 and 50 in the image of the receiver 43. Is combined with the video signal of the imaging device 1 and supplied to the receiver 43.

The output of the synchronous detector 45 is further supplied to a gate 55
And 56. Delay circuit 57 and control circuit 58
In the gate control wave survive T ₆ hours late T ₅ hours from the horizontal synchronization signal H as shown in is made FIG. 3 (d), the gate 55 is opened by this. The duration T ₆ of this gate control wave has a very short time width.
(B) located in the center of the duration T ₂ of the gated wave shown in.

Further, in the delay circuit 59 and control circuit 60, T ₇ from the vertical synchronizing signal V as shown in FIG. 4 (d)
Gating wave survive T ₈ hours made the delay time, the gate 56 is opened by this. The gating wave is located in the middle of the duration T ₄ of the gate control wave shown in Figure 4 (b). The outputs of the gates 55 and 56 are supplied to the AND circuit 1, and when both gates have an output, the AND output appears.

The AND output of the circuit 61 is provided by a switching mechanism 62 of switches 41 and 42, a lighting switch 63 of the light source 18 for infrared illumination, and a magnification switching mechanism 64 of the imaging lens system 25.
And the Z-direction drive mechanism 5 for moving the imaging device 1 in the Z-direction.

Reference numeral 66 denotes an automatic focus adjustment circuit,
And 42 are switched by the switching mechanism 62 to be in an operating state, and a high-magnification video signal obtained by infrared illumination from the light source 18 is supplied to the gate 6 via the switch 41.
7 and a wave height discrimination circuit 68. When the imaging device 1 advances in the direction of the eyeball 6 from the distant position by the Z-direction drive mechanism 5, the strong surface reflected light signal R and the corneal endothelial cell image signal I are almost constant as shown in FIG. While maintaining the time interval t of the horizontal synchronizing signal H as shown by the arrow. Then, as shown in FIG.
Comes to the position of time T from the synchronization signal H, the imaging device 1
Focus exactly on the corneal endothelial cells.

The wave height discrimination circuit 68 extracts only the surface reflected light signal R by wave height discrimination, utilizing the fact that the surface reflected light signal R is extremely strong. Meanwhile the delay circuit 69 and the control circuit 70, creates a gating wave duration T ₁₀ to a position delayed T ₉ hours from the synchronizing signal H, as shown in FIG. 5 (c), thereby to open the gate 71. Here, the delay time T ₉ of the delay circuit 69 is selected to be equal to (T−t).
Accordingly, the surface reflection image signal R passes through the gate 71 at the moment when the focus of the imaging device 1 matches the corneal endothelial cell.

The output of the gate 71 based on the surface reflection image signal R controls the strobe power supply 72 to cause the strobe flash tube 12 to emit light, and operates the frame control circuit 73 for one image time (1/30 second). A gate control wave is generated, whereby the gate 67 is opened, and one image of the video signal captured by the strobe light is stored in the frame memory 74. The stored image in the frame memory 74 is repeatedly read out, sent to the receiver 43 via the switch 42, and displayed on the screen.

The imaging of corneal endothelial cells by the above-described device
Perform as follows. First, the infrared light source 7 for iris illumination is turned on to illuminate a wide area of the eyeball 6, the light source 31 is turned on by the modulation power supply 44, and the infrared spot light is projected on the eyeball 6, and the fixation target light source 27 is turned on. Then, when imaging is performed with the imaging lens system 25 set to a low magnification, an image as shown in FIG. 6 is displayed on the receiver 33, for example.

In FIG. 6, 81 is an iris, 82 is a pupil,
83 is a reflection image of the infrared light source for iris illumination on the cornea surface, 84
Is a reflection image of the infrared spot light on the corneal surface. Also,
Reference numeral 85 denotes an outline drawn by a signal generated by the area display circuit 54. Normally, since the infrared spot light often hits the eyeball 6 from an oblique direction, the reflected image 84 appears at a position off the center of the image, and the infrared spotlight is applied to the center of the eyeball 6 from directly in front. Then, as shown, the reflection image 84 comes to the center of the screen.

When the position of the imaging device 1 is manually adjusted to bring the infrared spot light reflected image 84 into the outline 85, the reflected image signal S obtained by the synchronous detector 45 is output to the gates 46 and 50.
And the outputs of the gates 46 and 50 output the X-direction position control circuit 49 and the Y-direction position control circuit 5.
3 operates to drive the X-direction drive mechanism 3 and the Y-direction drive mechanism 4, and automatically adjusts the position of the imaging device 1 so that the reflected image 84 comes to the center of the contour 85.

When the reflected image 84 of the infrared spot light comes to the center of the outline 85, the imaging device 1 faces the eyeball 6. Then, the reflected image signal S matches the time zone T ₆ of the gate control wave shown in FIG. 3D and the time zone T ₈ of the gate control wave shown in FIG. 56, and AND gate 61 produces an AND output.
Based on the AND output, the automatic focusing operation and the imaging of the imaging apparatus 1 are performed as follows.

The AND output controls the switch switching circuit 62 to switch the switches 41 and 42 to positions different from those shown in the figure, whereby the video signal of the image pickup apparatus 1 is supplied to the automatic focus adjustment circuit 66 and Reference numeral 43 repeatedly displays the image stored in the frame memory 74. When the lighting switch 63 of the light source 18 is closed and illumination with infrared light is performed, and the magnification switching circuit 64 operates to switch the imaging lens system 25,
Since the imaging device 1 magnifies and captures a small portion at the center of the eyeball 6 with infrared light, as shown in FIG. 5A, the video signal includes a corneal surface reflection signal R and a corneal endothelial cell image signal I due to infrared light. Appears.

When the Z-direction drive mechanism 5 operates, the imaging device 1 moves on the central axis of the eyeball 6 toward the eyeball, thereby maintaining the interval t between the surface reflection signal R and the endothelial cell image signal I. While moving in the direction indicated by the arrow in FIG.
And at the moment when the surface reflected signal R has come to the position of the T ₉ hours from the horizontal synchronizing signal H, the surface reflection signal R passes through the gate 71, thereby causing the electronic flash flash tube 12, the video signal due to the visible light Obtained by the imaging device 1. One image of this video signal is stored in the frame memory 74 through the gate 76 and is displayed by the receiver 43.

[0034]

As it is evident from the foregoing description, since it is possible to directly face the rapidly automatically reliably eyeballs the imaging device when according to the present invention, to obtain a corneal endothelial cell image focusing is matched extensively The effect can be further enhanced by implementing this together with the automatic focusing mechanism.

[Brief description of the drawings]

FIG. 1 is an optical path diagram of an embodiment of the present invention.

FIG. 2 is a block diagram of an electric circuit of the embodiment.

FIG. 3 is a signal waveform diagram for controlling driving in an X direction in the embodiment.

FIG. 4 is a signal waveform diagram for controlling driving in the Y direction in the embodiment.

FIG. 5 is a signal waveform diagram for explaining the operation of the automatic focusing mechanism in the embodiment.

FIG. 6 is a view showing a low magnification display image in the embodiment.

FIG. 7 is a diagram illustrating the relationship between corneal surface reflected light and endothelial cell image light.

FIG. 8 is a block diagram showing an electric circuit of a conventional eyeball imaging apparatus including only an automatic focusing mechanism.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 imaging device 2 central axis 3 Y-direction drive mechanism 4 Y-direction drive mechanism 6 eyeball 11 illumination optical path 21 imaging optical path 31 infrared spotlight light source 33 infrared filter 34 pinhole 36 projection lens 43 receiver 44 modulation power supply 45 synchronous detector 46 Gate 47 Delay circuit 48 Gate control circuit 49 X-direction control circuit 50 Gate 51 Delay circuit 52 Gate control circuit 53 Y-direction control circuit 55-61 Detection circuit for completion of control in X-direction and Y-direction 66 Automatic focus adjustment circuit

Claims (1)

(57) [Claims] 1. A light source for irradiating illumination light toward an eyeball;
In an eyeball imaging apparatus having means for imaging a television image of an image light beam based on the illumination light obtained from a different direction, the eyeball is modulated at a constant frequency from the central axis direction located between the illumination light and the image light beam. Means for irradiating spot light having a small diameter, means for synchronously detecting an image signal obtained by the imaging at the frequency, and extracting only a reflected light signal of the spot light on the corneal surface, and In sync
Corresponds to a predetermined section in the TV image displaying this imaging signal
Gate means to open and
Eye portion irradiated by the spot light on the basis of the reflected light signal at the corneal surface of the spot light is orthogonal to the entire device to come at a fixed position within the compartment in the TV image displayed the image pickup signal to the central axis A centering device in an eyeball imaging device, comprising: means for adjusting movement in a direction.