JPH10234670A - Ophthalmologic inspecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly and stably execute tracking of a desired vein in the fundus of an eye. SOLUTION: When tracking is started, a vein image picked-up by one dimensional CCD 42 is read by a timing generated in a timing generating part 69 and only a vein image signal is extracted in a vein part extracting part 71. The output is arithmetically processed in MPU 62 from an AGC part 72 with an A/D converter 63 so as to be outputted as an AGC gain for detecting a vein position in a succeeding sample cycle from a D/A converter 63. The signal waveform and the signal waveform for tracking from a low pass filter are calculated in a dividing part 57 and an AGC processing for vein position detection is executed as against a vein signal to be executed tracking. The output signal of the dividing part 57 becomes the vein position signal by way of a differential circuit 64 and a zero-cross comparing part 65 and compared with a tracking center position signal from an I/O interface 60 in a vein position arithmetic part 66. The shift quantity of the vein closest to a tracking center is outputted to a galvanometric mirror control part 67 and a galvanometric mirror 22 is driven so as to compensate the shift quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus examination apparatus for examining blood vessels on the fundus.

[0002]

2. Description of the Related Art Conventionally, as an ophthalmic examination apparatus for tracking the movement of blood vessels on the fundus of an eye to be examined, for example, as described in JP-A-63-288133,
An apparatus that detects movement of two blood vessels to perform two-dimensional tracking, and detects movement perpendicular to the running direction of one blood vessel as described in Japanese Patent Application Laid-Open No. 6-503733. There are known devices that perform one-dimensional tracking.

In these ophthalmic examination apparatuses, a one-dimensional C is used as a light receiving means for receiving the reflected light of the tracking light at the fundus.
Using a CD, waveform processing of a blood vessel image signal is performed to calculate a shift amount between the tracking center position and the position of the blood vessel image, and tracking is performed. At this time, in order to optimize the level of the blood vessel image signal, the amplification factor of the amplifier is electrically or manually adjusted manually or automatically so that the output signal level of the one-dimensional CCD falls within the set range. The amplification factor of the amount of light incident on the one-dimensional CCD by the image intensifier placed in front of the original CCD is adjusted in a similar manner.

Further, there has been proposed an apparatus which detects a relative position of a moving object with respect to a one-dimensional CCD and continuously feeds back the position signal to an imaging direction changing means for changing an imaging direction, thereby enabling tracking and capturing of the object. ing.

[0005]

However, in the above-mentioned prior art, a method for electrically adjusting the amplification factor of an amplifier, a one-dimensional CCD using an image intensifier, and the like.
In the method of adjusting the amplification factor of the amount of incident light to the light, since the amplification factor is adjusted so that a bright portion on the fundus that is not a blood vessel does not saturate, the waveform signal level of a small blood vessel having a small contrast is extremely small, which is favorable. Sometimes tracking is not possible.

In actual measurement, the patient's eyeball is not completely stationary and repeats fine movement during fixation. Therefore, the laser beam follows the fine movement. There must be. However, when a large blood vessel with a large contrast and a small blood vessel with a small contrast are close to each other, tracking is applied when the large blood vessel with a large contrast approaches the tracking center position due to eye movements such as eye fixation. There is a problem that tracking is applied to a thick blood vessel rather than a thin blood vessel having a small contrast.

Further, even in an apparatus capable of tracking and capturing an object, a signal processing method until a blood vessel position is extracted is not disclosed.

An object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide an ophthalmic examination apparatus that accurately and stably performs tracking on a desired fundus blood vessel.

[0009]

According to the present invention, there is provided an ophthalmologic examination apparatus for illuminating a region including a specific portion of a fundus as a target, and an image of the specific portion. An imaging unit that outputs a video signal by using the processing unit; a processing condition determination unit that determines a processing condition based on an output signal from the imaging unit or a signal in the vicinity of the specific portion in a processing result of the output signal; It is characterized by having a part extracting means for extracting the specific part in accordance with a condition determining means, and an automatic tracking means for automatically tracking the specific part based on an output of the part extracting means.

An ophthalmologic examination apparatus according to the present invention includes: an illuminating means for illuminating a region including a specific portion of a fundus to be a target; an imaging means for capturing an image of the specific portion and outputting a video signal; Processing condition determining means for determining a processing condition based on an output signal from an imaging means or a signal near the specific part in a processing result of the output signal; and extracting the specific part according to the processing condition determining means Site extraction means;
A display unit for displaying a processing result of the processing condition determining unit; and an automatic tracking unit for automatically tracking the specific part based on an output of the part extracting unit.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 shows a configuration diagram of a fundus blood flow meter according to a first embodiment, in which an observation light source 1 composed of a tungsten lamp or the like that emits white light and an objective lens 2 facing an eye E to be examined.
, A condenser lens 3, for example, a field lens 4 with a band-pass filter that transmits only light in the yellow range, a ring slit 5 almost conjugate to the pupil Ep of the eye E, and the lens of the eye E A conjugate light-blocking member 6, a relay lens 7, a transmissive liquid crystal panel 8, which is a fixation target display element movable along the optical path, a relay lens 9, a light-blocking member 10 conjugate with the vicinity of the cornea of the eye E to be examined, and a perforated hole. Mirror 1
1. Bandpass mirrors 12 that transmit light in the yellow range and reflect most of the other light beams are sequentially arranged.

A fundus observation optical system is provided behind the perforated mirror 11, and includes a focus lens 13, a relay lens 14, a scale plate 15, and an optical path switching mirror that can be inserted into and removed from the optical path. 16, eyepiece 17
Are sequentially arranged to reach the examiner's eye e. A television relay lens 18 and a CCD camera 19 are arranged on the optical path in the reflection direction when the optical path switching mirror 16 is inserted in the optical path, and the output of the CCD camera 19 is connected to a liquid crystal monitor 20. ing.

An image rotator 21 and a double-side polished galvanometric mirror 22 having a rotation axis perpendicular to the plane of the drawing are arranged on the optical path in the reflection direction of the band-pass mirror 12, and a lower reflection surface of the galvanometric mirror 22 is provided. A second focus lens 23 that is movable along the optical path is arranged in the reflection direction of 22a, and a lens 24 and a focus unit 25 that is movable along the optical path are arranged in the reflection direction of the upper reflection surface 22b. ing. The front focal plane of the lens 24 has a conjugate relationship with the pupil Ep of the eye E to be inspected, and the galvanometric mirror 22 is arranged on this focal plane.

Behind the galvanometric mirror 22, an optical path length compensating meniscus 26, a black spot plate 27 having a light shielding portion in the optical path, and a concave mirror 28 are arranged concentrically on the optical path. Lower reflective surface 22a
A relay optical system that guides a light beam that is not reflected by and passes through to the upper reflecting surface 22b of the galvanometric mirror 22 is configured. The meniscus 26 for correcting the optical path length is used to correct that the positions of the upper reflecting surface 22b and the lower reflecting surface 22a of the galvanometric mirror 22 have a shift in the vertical direction in the drawing caused by the mirror thickness. Yes,
It acts only in the optical path toward the image rotator 21.

In the focus unit 25, a dichroic mirror 29 and a condenser lens 30 are arranged on the same optical path as the lens 24, and a shaping mask 31 and a mirror 32 are arranged on the optical path in the reflection direction of the dichroic mirror 29.
The focus unit 25 can be integrally moved along the optical path in the direction indicated by the arrow.

On the optical path in the incident direction of the condenser lens 30,
Fixed mirror 33, optical path switching mirror 3 retractable from optical path
4, a collimator lens 35 and a measuring laser diode 36 that emits coherent red light, for example, are arranged on the optical path in the incident direction of the optical path switching mirror 34. Further, on the optical path in the incident direction of the mirror 32, a beam expander 37 composed of a cylindrical lens or the like, and a tracking light source 38 that emits, for example, green light different from other high-luminance light sources are arranged.

On the optical path behind the second focus lens 23, a dichroic mirror 39, a field lens 40, a magnifying lens 41, and a one-dimensional CCD 42 with an image intensifier are sequentially arranged to form a blood vessel detection system. ing. On the optical path in the reflection direction of the dichroic mirror 39, an imaging lens 43, a confocal stop 44, and mirror pairs 45a and 45b substantially conjugate to the pupil Ep of the eye E to be inspected are arranged, and the reflections of the mirror pairs 45a and 45b are arranged. Photomultipliers 46a and 46b are arranged in the directions, respectively.
A light receiving optical system for measurement is configured.

Although all the optical paths are shown on the same plane for the sake of illustration, the laser diode 36 is used for the mask 3.
1, the measurement light path in the emission direction of the tracking light source 38, and the reflection light paths of the mirror pairs 45a and 45b are each orthogonal to the plane of the paper.

Further, a system controller 47 for controlling the entire apparatus is provided. The system controller 47 includes an output of the one-dimensional CCD 42, photomultipliers 46a and 46.
b are connected to each other, and the system controller 4
The output of 7 is connected to the galvanometric mirror 22 and the optical path switching mirror 34, respectively.

FIG. 2 shows a block diagram of the system control unit. The output of the one-dimensional CCD 42 is connected to an amplifier 50 and a sample-and-hold circuit 51 in this order.
Output from the peak hold circuit 52 and the inversion buffer 53
Connected to each other. Peak hold circuit 52,
The outputs of the inverting buffers 53 are respectively connected to an adding circuit 54, and the output of the adding circuit 54 is connected to a low-pass filter 55. The output of the low-pass filter 55 is connected to a peak hold circuit 56 and a divider 57, and the output of the peak hold circuit 56 is connected to an A / D converter 59 via a sample hold circuit 58.

The A / D converter 59 is connected to the I / O
/ O interface 60, memory 61, MPU 62, D
The output of the D / A converter 63 is connected to the dividing unit 57. Further, the output of the dividing unit 57 is connected to a differentiating circuit 64, and is connected to a blood vessel position calculating unit 66 through a zero cross comparing unit 65. The output from the I / O interface 60 is also connected to the blood vessel position calculation unit 66, and the blood vessel position calculation unit 6
The output of 6 is connected to the galvanometric mirror 22 via the galvanometric mirror control unit 67.

The output of the clock pulse generator 68 is connected to the MPU 62 and the timing generator 69.
The output of the timing generator 69 is a one-dimensional CCD 42, sample and hold circuits 51 and 58, and a peak hold circuit 5.
2, 56, are connected to the division unit 57, the output of the I / O interface 60 is connected to the optical path switching mirror 34, and the output of the input unit 70 is connected to the I / O interface 60.

An amplifier 50, a sample hold circuit 51,
58, peak hold circuits 52 and 56, inversion buffer 5
3, by the addition circuit 54, the division unit 57, and the differentiation circuit 64,
The blood vessel site extraction unit 71 is configured, and the peak hold circuit 5
6, A by the dividing unit 57 and the sample hold circuit 58
A CG (Automatic gain control) unit 72 is configured. Also, the A / D converter 63 and the I / O interface 6
0, the memory 61, the MPU 62, and the D / A converter 63 constitute a processing condition determining unit 73. The zero-cross comparing unit 65, the blood vessel position calculating unit 66, and the galvanometric mirror control unit 67 constitute an automatic tracking control unit 74. Have been.

FIG. 3 shows the arrangement of each light beam on the pupil Ep of the eye E to be examined. I is an image of the ring slit 5 in an area illuminated by yellow illumination light, O is a light beam for observing the fundus oculi, and O is a perforated mirror.
1 is an image of an opening, V is a measurement / vessel received light beam, an image of an effective portion of the upper and lower reflecting surfaces of the galvanometric mirror 22, Da, Db
Is a pair of mirrors 45a and 45b respectively
It is an image of. P2 and P2 'are incident positions of the measurement light, and indicate the positions of the measurement light selected by switching the optical path switching mirror 34. A region M indicated by a chain line is an image of the lower reflection surface 22a of the galvanometric mirror 22. .

The white light emitted from the observation light source 1 passes through the condenser lens 3, and only the yellow wavelength light is transmitted by the field lens 4 with the band pass filter, passes through the ring slit 5, the light shielding member 6, the relay lens 7, The transmissive liquid crystal panel 8 is illuminated from behind, and the relay lens 9 and the light shielding member 1 are illuminated.
0, is reflected by the perforated mirror 11, and only the light in the yellow range is transmitted through the band-pass mirror 12,
After the light is once formed as a light flux image I by the fundus illumination light on the pupil Ep of the eye E through the eye E, the fundus Ea is illuminated almost uniformly.

At this time, a fixation target is displayed on the transmissive liquid crystal plate 8, projected onto the fundus Ea of the eye E by illumination light, and presented to the eye E as a target image. The ring slit 5 and the light shielding members 6 and 10 are for separating the fundus illumination light and the fundus observation light in the anterior segment of the eye E to be inspected. Does not matter.

The reflected light from the fundus oculi Ea returns along the same optical path, is extracted from the pupil Ep as a fundus observation light beam O, passes through the opening at the center of the perforated mirror 11, the focus lens 13, the relay lens 14, and passes through the scale plate. After the image is formed as a fundus image Ea ′ at 15, the light reaches the optical path switching mirror 16.

Here, when the optical path switching mirror 16 is retracted from the optical path, the fundus image Ea 'can be observed by the examiner's eye e via the eyepiece 17, while the optical path switching mirror 16 is inserted into the optical path. The scale plate 15
The fundus image Ea ′ formed above is re-formed on the CCD camera 19 by the television relay lens 18 and is projected on the liquid crystal monitor 20. While observing this fundus image Ea ', the eyepiece 1
7 or the liquid crystal monitor 20 aligns the apparatus.

The measuring light emitted from the laser diode 36 is collimated by a collimator lens 35, and is reflected by the optical path switching mirror 34 and the fixed mirror 33 when the optical path switching mirror 34 is inserted in the optical path.
When the optical path switching mirror 34 is retracted from the optical path while passing below the condenser lens 30, it passes directly above the condenser lens 30 and passes through the dichroic mirror 29.

On the other hand, the tracking light emitted from the tracking light source 38 has its beam diameter expanded by a beam expander 37 at different magnifications in the vertical and horizontal directions, is reflected by a mirror 32, and is shaped into a desired shape by a shaping mask 31. ,
Reflected by the dichroic mirror 29, the shaping mask 3
The measurement light having a spot-like image formed at a position conjugate with the center of the opening 1 is weighted by the condenser lens 30.

The measurement light and the tracking light are transmitted to the lens 24
Through the upper reflecting surface 2 of the galvanometric mirror 22
2b, and after passing through the black point plate 27, the concave mirror 4
8 again, the black spot plate 27, the meniscus plate 2 for optical path length correction
6 and is returned to the galvanometric mirror 22.

Here, an upper reflecting surface 22b and a lower reflecting surface 22a of the galvanometric mirror 22 are formed by a relay optical system disposed above the galvanometric mirror 22.
3 is provided in the optical path of the dichroic mirror 22 by inserting or retracting the optical path switching mirror 34 in the optical path. The measurement light and the tracking light reflected at the position of P are located at the notch of the dichroic mirror 22 this time.
2, P2 'is returned to the position, and the image rotator 2 is not reflected by the dichroic mirror 22.
Go to 1. Then, the measurement light and the tracking light deflected by the bandpass mirror 12 toward the objective lens 2 via the image rotator 21 are applied to the fundus oculi Ea of the eye E through the objective lens 2.

As described above, the measurement light and the tracking light are reflected in the upper reflecting surface 22b of the galvanometric mirror 22, and when returning, are incident on the galvanometric mirror 22 in a state of being decentered from the optical axis of the objective lens 2. As a result, as shown in FIG. 3, after forming an image as a spot image P2 or P2 'on the pupil Ep, the fundus oculi Ea is illuminated in a point-like manner.

The scattered reflected light from the fundus oculi Ea is again reflected by the objective lens 2.
The light is reflected by the band-pass mirror 12, passes through the image rotator 21, is reflected by the lower reflection surface 22a of the galvanometric mirror 22, passes through the focus lens 23, and is separated by the dichroic mirror 39. The tracking light passes through the dichroic mirror 39, and is transmitted by the field lens 40 and the imaging lens 41.
An image is formed as a one-dimensional CCv.

A part of the scattered and reflected light from the fundus oculi Ea due to the two light beams passes through the band-pass mirror 12 and is guided to the fundus observation optical system behind the perforated mirror 11. Here, the tracking light is a bar-shaped indicator T on the scale plate 15.
And the measurement light is formed as a spot image at the center of the indicator T. These images are the eyepiece 1
7 or the fundus image Ea ′ and the optotype image via the liquid crystal monitor 20. At this time, a spot image (not shown) is superimposed and observed at the center of the indicator T, and the indicator T is operated by an operation member such as an operation rod of the input unit 70.
It can move one-dimensionally on the fundus oculi Ea.

The examiner first focuses the fundus image Ea '. When the focus knob of the input unit 70 is adjusted, the transmissive liquid crystal plate 8, the focus lenses 13, 23, and the focus unit 25 are moved along the optical path in conjunction with the drive unit (not shown). When the fundus image Ea 'is in focus, the transmissive liquid crystal plate 8, the scale plate 15, the one-dimensional CCD 42, and the confocal stop 44 are simultaneously conjugated to the fundus Ea. The examiner has a fundus image E
While observing the focus state on a ', the depth of the blood vessel Ev to be measured is set, and the fundus image Ea' is focused.

After the focusing is completed, the examiner guides the line of sight of the eye E to change the observation area, and operates the input unit 70 to move the blood vessel Ev to be measured to an appropriate position. The system control unit 47 drives a control circuit that controls the transmissive liquid crystal panel 8 to move the target image. And the input unit 7
The indicator T is rotated by operating the operation rod 0 so that the indicator T is perpendicular to the traveling direction of the blood vessel Ev to be measured. The system control unit 47 drives a control circuit for controlling the image rotator 21, drives the image rotator 21, and rotates the indicator T.

After confirming the tracking, the examiner presses the measurement switch of the input unit 70 to start the measurement. The measurement light is reflected by the dichroic mirror 39, passes through the opening of the confocal stop 44, is reflected by the mirror pairs 45a and 45b, and is received by the photomultipliers 46a and 46b, respectively. The outputs of the photomultipliers 46a and 46b are output to the system control unit 47, and the received light signal is subjected to frequency analysis to obtain the blood flow velocity of the fundus oculi Ea.

First, as shown in FIG. 4, when there is no blood vessel Ev around the blood vessel Ev1 to be tracked, when the examiner starts tracking, the blood vessel image Ev 'picked up by the one-dimensional CCD 42 is converted to a timing generation unit. It is read out at the timing generated at 69 and amplified by the amplifier 50. Amplifier 5
The output signal of 0 is sampled and held by the sample and hold circuit 51 at the timing generated by the timing generation section 69. Since the part of the blood vessel Ev is dark and the peripheral part of the blood vessel Ev is bright, a waveform as shown in FIG. Here, a portion having a high output level indicates a bright portion.

The output signal of the sample hold circuit 51 is input to the peak hold circuit 52,
The peak hold is performed only during the L-level period of FIG. 5A generated by step 9 and the input signal is output as it is during the other periods. The output of the peak hold circuit 52 and the signal obtained by inverting the output of the sample and hold circuit 51 by the inverting buffer 53 are input to the adder circuit 54, and are added to each other.
As shown in (e), only the blood vessel image signal is extracted. The output of the adding circuit 54 is input to the low-pass filter 55,
The high frequency component is cut as shown in FIG.

The output of the low-pass filter 55 is input to a peak hold circuit 56, which performs peak hold only during the L-level period in FIG. The sample-and-hold circuit 58 corresponds to L in FIG.
Sampling is performed during the period of the level and held during the period of the H level. The output signal of the sample-and-hold circuit 58 is shown in FIG. 5 (f) together with the output waveform of the low-pass filter 55. The output signal is input to the A / D converter 59, converted into digital data, and processed by the MPU 62. ,
The signal is output from the D / A converter 63 as an AGC gain for detecting a blood vessel position in the next sample cycle.

FIG. 5 shows a waveform when the signal level input to the A / D converter 59 by the MPU 62 is set to the D / A converter 63 as it is. The output waveform of the D / A converter 63 is input to the division unit 57 as an AGC gain for detecting a blood vessel position, and the output waveform of the low-pass filter 55 is input to the division unit 57 as a tracking signal waveform.
Then, (the output signal of the low-pass filter 55) ÷ (the output signal of the D / A converter 63) is calculated, and the AGC for detecting the blood vessel position is applied to the blood vessel signal to be tracked by sampling in the period A.

The output signal of the divider 57 shown in FIG. 5 (h) is differentiated by a differentiator 64, and the output of the differentiator 64 is input to a zero-cross comparator 65 and compared with about 0V. It is output as a blood vessel position signal as shown in FIG. This blood vessel position signal is transmitted to the I / O interface 60.
Is compared with the tracking center position signal output from the control unit and the blood vessel position calculating unit 66, and outputs the deviation amount of the blood vessel closest to the tracking center to the galvanometric mirror control unit 67. The galvanometric mirror control section 67 drives the galvanometric mirror 22 so as to compensate for this shift amount.

Next, a case where a blood vessel Ev3 having a higher contrast than the blood vessel Ev2 exists around the blood vessel Ev2 to be tracked as shown in FIG. 6 will be described based on the output waveform shown in FIG. When the MPU 62 sets the signal level input to the A / D converter 59 as it is in the D / A converter 63, the deviation amount d from the tracking center of the blood vessel Ev2 becomes smaller in the sample period of n = 0. Since it is smaller than the displacement d ′ of the blood vessel Ev3 from the tracking center, the blood vessel position calculation unit 66 outputs the displacement d of the blood vessel closest to the tracking center to the galvanometric mirror control unit 67. The galvanometric mirror control unit 67 drives the galvanometric mirror 22 so as to compensate for this shift amount, and in the sample period of n = 1, the blood vessel Ev2 is imaged substantially at the tracking center.

However, since the AGC for detecting the blood vessel position at the sample period n = 1 is controlled by the gain based on the blood vessel Ev3, the signal of the blood vessel Ev2 is small as shown in FIG. The value is normalized to a value, and the output of the zero cross comparator 65 becomes unstable. On the other hand, an appropriate AGC is applied to the video signal of the blood vessel Ev3, and the output of the zero-cross comparison unit 65 is stabilized. Therefore, the output blood vessel position calculation unit 66 calculates the deviation amount of the blood vessel whose blood vessel position signal of the blood vessel Ev3 is closest to the tracking center. And the tracking may be applied to the blood vessel Ev3.

In order to prevent this phenomenon, arithmetic processing is performed by the MPU 62 in accordance with the flowchart shown in FIG. In step S1, it is determined whether or not the mode is the tracking mode. If the mode is the tracking mode, the video signal output from the sample and hold circuit 51 is converted into digital data by the A / D converter 59 in step S2, and the waveform analysis is performed by the MPU 62. Then, a blood vessel diameter closest to the tracking center position is calculated at a sample period n = 0.

Further, according to the calculated blood vessel diameter in step S 3, the MPU 62 instructs the timing generator 69 via the I / O interface 60 within the effective range of the AGC of the AGC unit 72 for detecting the blood vessel position. A signal for changing the peak hold time of a certain peak hold circuit 56 is output, and the peak hold time is changed from A to B as shown in FIG. In this embodiment, the effective range of the AGC for detecting the blood vessel position is changed so that the peak hold time becomes about twice the diameter of the blood vessel.

Further, FIG. 10 shows waveforms at n = 3 to 5 after the sample period n = 2 shown in FIG. This is n =
This shows a case where the tracking is shifted due to some disturbance in the sample period of 4, and the video signal of the blood vessel Ev3 is included in the effective range of the AGC for detecting the blood vessel position, that is, in the period B. As shown in FIG. 10 (g), at the sample period n = 4, a part of the video signal of the blood vessel Ev3 is sampled and held by the sample hold circuit 58, and the A / D converter 5
9 and output from the D / A converter 63 for the AGC gain for detecting the blood vessel position at the sample period n = 5. AG for detecting blood vessel position at sample period n = 5
The C gain is 1 / Va, which is smaller than the gain value 1 / Vb for multiplying the blood vessel Ev2 by an appropriate AGC, and the output signal of the blood vessel Ev2 of the zero cross comparator 65 shown in FIG. 10 (i) becomes unstable.

For this purpose, the MPU 62 performs a calculation process as shown in the flowchart of FIG. Steps
In S10, it is determined whether the mode is the tracking mode. If the mode is the tracking mode, the counter for determining the number of times of sampling the signal level output from the sample and hold circuit 58 is reset in step S11. If the number of times of sampling is within the predetermined number, it is determined in step S12 whether or not the sampling of the sample-and-hold circuit 58 has been completed. If the sampling has been completed, the signal output from the sample-and-hold circuit 58 in step S13 is used as it is. Set the D / A converter 63 to output
In S14, the signal level output from the sample hold circuit 58 is stored in the memory 61. When the number of samplings reaches the predetermined number in steps S15 and S16, the average value of the signal output from the sample and hold circuit 58 is calculated in step S17, and the D / A converter 63 is set so as to output the value in step S18. I do.

In this embodiment, the predetermined number is set to n = 3, and in FIGS. 9 and 10, the sample period n = 0.
In steps (1) to (3), the signal output from the sample and hold circuit 58 is output as it is, and AGC for detecting a blood vessel position is performed. The AGC gain input to the divider 57 after the sample period n = 4 is fixed at an average value 1 / Vb for the sample periods n = 1 to 3. If the tracking is shifted due to some disturbance in the sample period n = 4, even if the video signal of the blood vessel Ev3 enters the effective range of the AGC for detecting the blood vessel position, ie, B, the zero-cross comparison in the sample period n = 5 Since the output signal of the blood vessel Ev2 of the section 65 is stabilized as shown in FIG. 10 (j), tracking is also stabilized.

FIG. 12 is a diagram showing the configuration of the second embodiment. In the focus unit 25, a half mirror 80 is disposed between the dichroic mirror 29 and the condenser lens 30. Unlike the first embodiment, a relay lens 81, a movable mask 82 indicating an AGC range for detecting a blood vessel position, and an LED light source 83 as a red light source are arranged at positions substantially conjugate to the mask 31. I have. Further, I / O of the processing condition determination unit 73 in FIG.
The output of the O interface 60 is connected to a movable mask drive circuit 84 that controls the movable mask 82. Other configurations are the same as those of the first embodiment, and the same members are denoted by the same reference numerals.

The image of the movable mask 82 is projected on the fundus oculi Ea of the eye E as a target J as shown in FIG. The target J indicates the effective range of the AGC for detecting the blood vessel position.

When the examiner determines that the tracking is difficult to be performed because the contrast of the blood vessels to be tracked is low or the blood vessels are thin while watching the state of the fundus image Ea ′ shown in FIG. By operating the input unit 70, the effective range of the tracking AGC is manually changed.
This information is transmitted to the MPU 62 via the I / O interface 60.
The MPU 62 changes the peak hold time of the peak hold circuit 56, which is the effective range of the AGC for detecting the blood vessel position, according to the input information of the input unit 70, controls the movable mask drive circuit 84, and controls the movable mask 82 Is driven, whereby the target J, which is the image of the movable mask 82, moves in the direction of the arrow in FIG.

Further, when automatically changing the AGC range of the tracking in the first embodiment, the target J may be projected onto the fundus oculi Ea of the eye E to be examined. In this case,
The target J also moves in conjunction with the range of the tracking AGC. Further, the configuration of automatically changing the first embodiment and the manual configuration of the second embodiment can be combined.

[0055]

As described above, the ophthalmologic diagnosis apparatus according to the present invention determines the processing conditions based on the signals in the vicinity of the specific part, extracts the specific part, and performs the automatic tracking, thereby obtaining the tracking light. AGC processing for detecting a blood vessel position is performed in a range narrower than the effective range, and waveform processing for normalizing a blood vessel image signal can be performed. Therefore, tracking can be stably performed even on a thin blood vessel having a small contrast. .

Further, the ophthalmic diagnostic apparatus according to the present invention determines processing conditions based on signals in the vicinity of a specific part, displays the result on display means, extracts the specific part, and performs automatic tracking. The range in which AGC for detecting a blood vessel position when tracking a blood vessel of the eye to be examined can be made variable, and tracking can be stably applied to a blood vessel having a low contrast among two adjacent blood vessels. Can be.

[Brief description of the drawings]

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

FIG. 2 is a configuration diagram of a block circuit of a system control unit.

FIG. 3 is an explanatory diagram of a light beam arrangement on a pupil Ep.

FIG. 4 is an explanatory diagram of an observation fundus image.

FIG. 5 is a timing chart of a tracking signal waveform.

FIG. 6 is an explanatory diagram of an observation fundus image.

FIG. 7 is a timing chart of a tracking signal waveform.

FIG. 8 is a flowchart.

FIG. 9 is a timing chart of a tracking signal waveform.

FIG. 10 is a timing chart of a tracking signal waveform.

FIG. 11 is a flowchart.

FIG. 12 is a configuration diagram of a second embodiment.

FIG. 13 is a front view of a tracking target.

FIG. 14 is an explanatory diagram of an observation fundus image.

[Explanation of symbols]

 Reference Signs List 1 observation light source 8 transmission liquid crystal plate 12 band pass mirror 19 CCD camera 20 liquid crystal monitor 21 image rotator 22 galvanometric mirror 25 focus unit 36 laser diode 38 tracking light source 42 one-dimensional CCD 46a, 46b photomultiplier 47 system control unit 54 addition circuit 55 low-pass filter 58 division unit 60 I / O interface 62 MPU 64 differentiating circuit 65 zero-cross comparison unit 66 blood vessel position calculation unit 67 galvanometric mirror control unit 69 timing generation unit 70 input unit 82 movable mask 83 red LED 84 Movable mask drive circuit

Claims (7)

[Claims] An illumination unit configured to illuminate an area including a specific portion of a fundus serving as a target; an imaging unit configured to capture an image of the specific portion and output a video signal; and an output signal from the imaging unit or the output. Processing condition determining means for determining a processing condition based on a signal in the vicinity of the specific part in a signal processing result; part extracting means for extracting the specific part in accordance with the processing condition determining means; and part extracting means An automatic tracking means for automatically tracking the specific part based on the output of the eye examination device. 2. The signal of the specific portion is a blood vessel image, and the processing condition determining means extracts only the signal of the blood vessel image portion and performs a normalization process of changing an amplification factor according to the signal of the blood vessel image portion. The ophthalmic examination apparatus according to claim 1, wherein the examination is performed. 3. The ophthalmic examination according to claim 2, wherein the processing condition determining means includes a normalization processing range setting means for setting an effective range of a normalization processing for changing an amplification factor according to the signal of the blood vessel image portion. apparatus. 4. The ophthalmologic examination according to claim 3, wherein the processing condition determining means includes a normalization processing range changing means for changing an effective range of a normalization processing for changing an amplification factor according to a signal of the blood vessel image portion. apparatus. 5. The ophthalmologic examination apparatus according to claim 4, wherein the normalization processing range changing means changes an effective range of the normalization processing according to a diameter of the blood vessel image. 6. The ophthalmologic examination apparatus according to claim 2, wherein the normalization process starts automatic tracking, changes an amplification factor for a certain period, and fixes the amplification factor thereafter. 7. An illuminating means for illuminating a region including a specific part of a fundus serving as a target, an image capturing means for capturing an image of the specific part and outputting a video signal, and an output signal or the output from the image capturing means Processing condition determining means for determining a processing condition based on a signal in the vicinity of the specific part in a signal processing result; part extracting means for extracting the specific part according to the processing condition determining means; An ophthalmologic examination apparatus comprising: display means for displaying a processing result of the means; and automatic tracking means for automatically tracking the specific part based on an output of the part extracting means.