JP2019115762A - Examination apparatus and control method for examination apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily obtain a tomographic image having good contrast even when an object to be measured is outside the range of the optical path length adjustment range of the apparatus. SOLUTION: A tomographic image acquisition means for acquiring a tomographic image of an object to be inspected based on a combined wave light obtained by combining a return light from an object to be inspected irradiated with measurement light and a reference light corresponding to the measurement light, and a subject. The focusing position changing means for changing the position of the focusing member in order to obtain the focusing state of the measurement light with respect to the inspection object, and the alignment by changing the relative position between the optical head having the focusing member and the object to be inspected. In an ophthalmic apparatus having an optical path length difference changing means for changing the optical path length difference between the measurement light and the reference light, the position within the position changing range of the focusing member by the focusing position changing means. A determination means for determining whether or not a focusing state can be obtained by the change and a control means for operating the alignment means according to the determination result of the determination means are arranged. [Selection diagram] Fig. 3

Description

  The present invention relates to an examination apparatus used for ophthalmologic medical treatment and the like, and a control method of the examination apparatus.

  At present, various devices using optical devices are used as an ophthalmic device which is one aspect of an inspection apparatus. For example, various devices such as an anterior segment imaging device, an eye fundus camera, a confocal laser scanning ophthalmoscope (SLO), and the like are used as optical devices for observing the eye.

  Among them, an optical coherence tomography (OCT, hereinafter referred to as an OCT apparatus) is an apparatus for obtaining a tomogram of a sample with high resolution, and is an indispensable apparatus for specialized outpatients of the retina as an ophthalmic apparatus. It is getting worse. The OCT apparatus emits low coherent light to an object to be inspected and scans the object to be inspected. Then, the return light from the inspection object of the measurement light is processed by the interference system to measure the luminance information and the like regarding the fault of the inspection object with high sensitivity. Further, based on the luminance information, it is possible to obtain a tomogram of the object to be inspected with high resolution. Therefore, since it is possible to obtain a high-resolution tomogram of the retina in the fundus of the subject's eye, it is widely used in ophthalmologic diagnosis of the retina.

  Here, the procedure of acquiring an OCT tomographic image will be briefly described. At the time of tomographic image acquisition, while viewing the anterior ocular segment observation image of the eye to be examined, alignment of the optical system with the eye to be examined is performed using a joystick or the like. After completion of alignment, an SLO fundus image is acquired, and based on this SOL fundus image, a focusing lens disposed in the SLO optical system is moved to perform focusing operation. At the same time, the coarse focusing operation of the OCT optical system is performed. Furthermore, after this, based on the OCT tomographic image, the reference mirror is moved to automatically adjust the coherence gate and precise auto focusing of the OCT optical system is performed. The adjustment of the coherence gate and the automatic focusing of the OCT optical system require complicated control or operation.

  With regard to such operations, Patent Document 1 performs alignment of the anterior segment based on the image of the anterior segment of the subject's eye, and if it is determined that the location is correct, adjust the position of the coherence gate. An automatic device is described.

Patent 5220155 publication gazette

  When the object to be examined is an eye, in the case of strong myopia or hyperopia, the effect of the diopter sometimes can not obtain an appropriate focusing state. In the above-described apparatuses, all focusing operations of the focusing lens can be automatically performed on an eye to be examined which is a diopter within the adjustment range of the optical path length changing means. However, when the diopter of the subject's eye deviates even from the adjustment range, it has been difficult to obtain an OCT image with a suitable contrast because an appropriate focusing state is not selected. In addition, since an appropriate contrast can not be easily obtained, the burden on the examiner is also large.

  The present invention has been made in view of such a situation, and it is possible to easily acquire an appropriate tomographic image of the eye to be examined even when the diopter of the eye to be examined exceeds the adjustment range of the ophthalmologic apparatus. An object of the present invention is to provide an inspection apparatus and a control method of the inspection apparatus.

In order to solve the above-mentioned subject, an inspection device concerning one mode of the present invention,
An image acquisition unit that acquires a tomographic image from interference light in which the return light from the fundus of the subject's eye irradiated with the measurement light interferes with the reference light corresponding to the measurement light;
Optical path length difference changing means for changing the optical path length difference between the optical path length of the measurement light and the optical path length of the reference light by moving the optical path length adjusting member;
Alignment means for changing the relative position between an optical head having a measurement optical system and an anterior segment of the subject's eye to align the optical head with the anterior segment of the subject's eye;
The tomographic image can be obtained by changing the position of the optical path length adjusting member within the changeable range of the optical path length difference changing unit while the optical head and the anterior segment of the subject's eye are aligned. Determining means for determining whether or not
A control unit that operates the alignment unit when it is determined by the determination unit that the tomographic image can not be obtained within the changeable range;
And the like.

  According to the present invention, an appropriate tomographic image can be easily obtained, and the burden on the examiner can be reduced.

It is a figure for demonstrating the measurement screen displayed on a monitor at the time of eye measurement about the ophthalmic system which concerns on one Embodiment of this invention. It is a schematic diagram for demonstrating each structure of the ophthalmologic apparatus which concerns on one Embodiment of this invention. It is a flow chart of control explaining operation for tomographic image photography in a 1st embodiment of the present invention. It is a flow chart of control explaining operation for tomographic image photography in a 2nd embodiment of the present invention.

  According to the ophthalmologic system or apparatus of the present invention, when automatic adjustment of the coherence gate position or automatic adjustment of the in-focus position after the end of the adjustment, the adjustment range of focus in the positional relationship between the eye to be examined and the optical system in the normal adjustment state This corresponds to the case of observation of the eye to be examined with a diopter not falling under In the present invention, in such a case, it is possible to select whether to prioritize the observation field of view or the tomogram contrast. Specifically, when the tomographic image resolution is prioritized, the positional relationship between the eye to be examined and the optical system is changed, and the optical system is automatically moved to a position where an optimal contrast can be obtained. This can reduce the burden on the examiner's operation. The present invention is not limited to an ophthalmologic system or device, and is applicable to a medical system or device such as an endoscope for observing an object to be examined such as the skin of a human body.

  The coherence gate is a position corresponding to the optical path length of the reference light in the optical path of the measurement light in OCT. Therefore, the position of the coherence gate can be changed by changing the light path length difference between the measurement light and the reference light by the light path length difference changing unit described later. The optical path length difference changing unit may be configured to move the position of the reference mirror in the optical axis direction, or to move the device in the optical axis direction with respect to the subject's eye. The driving mechanism of the provided moving stage can be exemplified.

(Schematic configuration of the device)
A schematic configuration of an ophthalmologic apparatus according to an embodiment of the present invention will be described using FIG. 2A which is a side view of the ophthalmologic apparatus. The ophthalmologic apparatus includes an optical head 900, a stage unit 950, a base unit 951, a personal computer 925, a display unit 928, an input unit 929, and a jaw base 323.

  The optical head 900 is a measurement optical system for acquiring an anterior segment image of an eye to be examined and a two-dimensional image or tomographic image of the fundus. The optical head 900 can be moved relative to a base unit 951 incorporating a spectroscope described later, using a stage unit 950 or moving unit moved by a motor or the like in the X, Y, and Z directions in the drawing. The personal computer 925, which also serves as the control unit of the stage unit 950, performs control of the stage unit and the configuration of a tomographic image. In the present embodiment, the stage unit 950 performs alignment by changing the relative position between the optical head 900 having a focusing member such as a focusing lens described later and the eye to be examined 107 in addition to the configuration for controlling this. Configure the means. The personal computer 925 includes a hard disk 926. The hard disk 926 also serves as a subject information storage unit, and stores programs for tomographic imaging.

  The personal computer 925 is connected to a display unit 928 such as a monitor and an input unit 929 including a keyboard, a mouse and the like. The input unit 929 also issues an instruction to a display control unit (not shown). A display unit 928 displays a measurement screen or the like to be described later on the display screen according to an instruction from the display control unit. The subject's eye is fixed by

(Configuration of measurement optical system and spectroscope)
Next, the configuration of the measurement optical system and the spectroscope of the ophthalmologic apparatus according to the present embodiment will be described with reference to FIG.

  First, the inside of the optical head 900 will be described. An objective lens 135-1 is disposed to face the subject's eye 107 of the subject, and a first dichroic mirror 132-1 and a second dichroic mirror 132-2 are disposed on the optical axis of the objective lens 135-1. Ru. The optical path from the subject's eye 107 is branched by the first dichroic mirror 132-1 into an optical path 353 for anterior eye observation, an optical path 352 for the fixation lamp and an optical path 351 of the OCT optical system according to the wavelength band. Ru. Further, the optical path after being branched into the optical path 353 is branched by the second dichroic mirror 132-2 into an optical path 352 for the fixation lamp and an optical path 351 of the OCT optical system according to the wavelength band. The optical path 352 is further branched by the third dichroic mirror 132-3 into the optical path to the CCD 172 for fundus observation and the optical path to the fixation lamp 191 for each wavelength band as described above.

  A focusing lens 135-3 and a lens 135-4 are arranged in this order on the optical path 352 from the second dichroic mirror 132-2 to the third dichroic mirror 132-3. The focusing lens 135-3 is driven in the optical axis direction along the light path 352 by a fixation lamp and a motor (not shown) for focusing adjustment for observation of the fundus.

  The CCD 172 is sensitive to the wavelength of the fundus observation illumination light (not shown), specifically, around 780 nm. On the other hand, the fixation lamp 191 generates visible light to promote fixation of the subject. The optical system for fundus observation may be configured by an optical system such as a scanning laser ophthalmoscope (SLO).

  A lens 135-2 and an infrared CCD 117 for anterior eye observation are disposed in this order on the light path 353 after splitting by the first dichroic mirror 132-1. The infrared CCD 171 is sensitive to the wavelength of the illumination light for anterior eye observation (not shown), specifically, around 970 nm. Further, on the light path 353, an image split prism (not shown) is disposed. Based on the split image of the anterior segment obtained from the image split prism, the distance of the optical head 900 in the Z direction relative to the eye 107 to be examined can be detected.

  The optical path 351 forms an OCT optical system as described above, and is for acquiring a tomographic image of the fundus of the eye 107 to be examined. More specifically, an interference signal for forming a tomographic image is obtained. The OCT optical system has an optical member disposed in the optical path of the measurement light, an optical member disposed in the optical path of the reference light, the light source 101, the optical coupler 131, and a spectroscope 180 for obtaining an interference signal from the interference light. In the present embodiment, the OCT optical system is a tomographic image of the fundus of the eye to be examined 107 based on combined light obtained by combining the return light from the test object irradiated with the measurement light and the reference light corresponding to the measurement light. A tomographic image acquisition unit configured to acquire an image is configured.

  The light emitted from the light source 101 is guided to the optical coupler 131 through the optical fiber 131-1 and separated there as the measuring light, and passes through the optical fiber 131-2 to the optical path of the measuring light. An XY scanner 134, a focusing lens 135-5, and a lens 135-6 are disposed on the optical path of the measurement light reaching the second dichroic mirror 132-2.

  The XY scanner 134 is used to scan the measurement light on the fundus of the eye 107 to be examined. Although the XY scanner 134 is illustrated as a single mirror, it performs scanning in the two axial directions of XY, and in actuality, two mirrors are used. The focusing lens 135-5 adjusts the focus of the measurement light from the light source 101 emitted from the fiber 131-2 on the fundus. For this reason, it drives on the optical axis along the optical path of measurement light by a motor (not shown). Further, as a result of this focusing adjustment, the reflected or scattered light from the fundus is simultaneously imaged in the form of a spot at the tip of the fiber 131-2 and is incident.

  Next, the optical path from the light source 101 and the configuration of the reference optical system will be described. The light emitted from the light source 101 is separated into the reference light by the optical coupler 131, passes through the optical fiber 131-3, and reaches the reference optical system. In the reference optical system, a lens 135-5, a dispersion compensating glass 115, and a mirror 132-4 are disposed from the side of the optical fiber 131-3. The above-described optical coupler 131 is connected to single-mode optical fibers 131-1-4 which are connected and integrated with the optical coupler. The reference light path 135-7 passes through the optical fiber 131-4 to the spectroscope 180. These configurations constitute a Michelson interferometer.

  Next, generation of interference light will be described. As described above, the light emitted from the light source 101 passes through the optical fiber 131-1, and is split into the measurement light guided to the optical fiber 131-2 side through the optical coupler 131 and the reference light guided to the optical fiber 131-3 side. Be done. The measurement light passes through the light path 351 of the OCT optical system described above and is irradiated to the fundus of the subject's eye 107 to be observed, and reaches the optical coupler 131 again through the same light path by reflection and scattering by the retina.

  On the other hand, the reference light passes through the optical fiber 131-3 and the lens 135-7, reaches the mirror 132-4 through the dispersion compensation glass 115 inserted for matching the dispersion of the measurement light and the reference light, and is reflected. Then, it returns to the same optical path and reaches the optical coupler 131 again. The measurement light and the reference light are combined by the optical coupler 131 to become interference light (also referred to as combined light). Here, interference occurs when the optical path length of the measurement light and the optical path length of the reference light become substantially the same.

  The mirror 132-4 can be positionally adjusted in the optical axis direction along the optical path of the reference light by a motor and a drive mechanism (not shown). As a result, it is possible to move the position of the mirror 132-4 to change the optical path length of the reference light, and to match the optical path length of the reference light with the optical path length of the measurement light changed by the eye 107 to be examined. The interference light is guided to the spectroscope 180 via the optical fiber 131-4.

  In the present embodiment, a polarization adjusting unit 139-1 on the measurement light side is provided in the optical fiber 131-2. Further, in the optical fiber 131-3, a polarization adjustment unit 139-2 on the reference light side is provided. These polarization control units have several portions in which optical fibers are drawn in a loop. By rotating the looped portion around the longitudinal direction of the fiber and twisting the fiber, it is possible to adjust and match the polarization states of the measurement light and the reference light. In this apparatus, the polarization states of the measurement light and the reference light are adjusted and fixed in advance.

  The spectroscope 180 is composed of lenses 135-8 and 135-9, a diffraction grating 181, and a line sensor 182. The interference light emitted from the optical fiber 131-4 becomes substantially parallel light through the lens 135-8, and then split by the diffraction grating 181 and imaged on the line sensor 182 by the lens 135-3. An interference signal based on the interference light obtained by the line sensor 182 is sent to a personal computer 925, which generates a tomographic image using the interference signal.

  Next, the periphery of the light source 101 will be described. The light source 101 is SLD (Super Luminescent Diode) which is a typical low coherent light source. The central wavelength of light obtained from the light source 101 is 855 nm, and the wavelength bandwidth is about 100 nm. Here, the bandwidth is an important parameter because it affects the resolution in the optical axis direction of the obtained tomographic image. Further, although the SLD is selected as the type of light source here, as long as low coherent light can be emitted, ASE (Amplified Spontaneous Emission) or the like can also be used. The center wavelength is preferably near infrared light in view of measuring the eye. In addition, since the central wavelength affects the lateral resolution of the obtained tomographic image, it is desirable that the central wavelength be as short as possible. For both reasons, the central wavelength of light used in this embodiment is 855 nm.

  As described above, in the present embodiment, the Michelson interferometer is used as the interferometer, but a Mach-Zehnder interferometer may be used. When the light amount difference between the measurement light and the reference light is relatively small, the Michelson interferometer in which the division unit and the combination unit are provided in common rather than the Mach-Zehnder interferometer in which the division unit and the combination unit are separately provided. It is desirable to use

(Tomogram acquisition method)
Subsequently, a method of acquiring a tomographic image will be described. A control unit (not shown) controls the XY scanner 134 in accordance with an instruction from the personal computer 925. As a result, the measurement light can be scanned on a desired site on the fundus of the eye 107 to be examined, and a tomographic image of the site can be obtained. Specifically, first, measurement light is scanned in the X direction on the fundus, and a predetermined number of imaging lights obtained from the imaging range in the X direction on the fundus are imaged by the line sensor 182. The luminance distribution on the line sensor 182 obtained at a certain position in the X direction is converted into a linear luminance distribution by FFT.

  The linear luminance distribution obtained by the FFT is converted into density or color information to obtain an image shown on the display unit 928. An image obtained after this conversion is called an A-scan image. A two-dimensional image obtained by arranging a plurality of A-scan images is called a B-scan image. A plurality of A-scan images for constructing one B-scan image are captured and synthesized. After obtaining one B-scan image, a plurality of B-scan images can be obtained by moving the scan position in the Y direction and performing the scan in the X direction again.

  The examiner can diagnose the eye to be examined by looking at the B-scan image displayed on the display unit 928 or a three-dimensional tomographic image constructed from a plurality of B-scan images.

(Measurement screen)
Subsequently, the measurement screen 1000 displayed on the display screen will be described with reference to FIG. On the measurement screen 1000, an anterior eye observation screen 1101 for displaying an image, a fundus two-dimensional image display screen 1201, and a tomographic image display screen 1301 are disposed. Further, on each display screen, sliders 1103, 1203 and 1302 for arranging so-called focus, contrast and the like of these images to display a suitable image are arranged.

  On the anterior eye observation screen 1101, an observation image of the anterior eye portion of the subject eye 107 obtained by the anterior eye observation CCD is displayed. Here, the observation image displayed on the anterior eye observation screen 1101 is a split image 1102 of the anterior eye part obtained by the image split prism provided in the anterior eye observation system. The split image 1102 is used when performing alignment between the optical head 900 and the eye 107 as described above.

  Further, on the fundus two-dimensional image display screen 1201, a two-dimensional image of the fundus of the subject's eye obtained by the fundus observation CCD is displayed. On the fundus two-dimensional image display screen 1201, an imaging range 1202 for capturing a tomographic image in the fundus image is also displayed. The tomographic image of the subject's eye is displayed at a display position based on the coherence gate position of the tomographic image display screen 1301.

  When the examiner presses one of the L button and the R button, the optical head 900 is moved to a position corresponding to one of the pressed left and right eyes. Ru. When the examiner moves the mouse 930 shown in FIG. 1B, which is the input means 929, on a desk or the like, the display position of the cursor 1002 displayed superimposed on the measurement screen 1000 in conjunction with this movement. Can be moved.

  In the ophthalmologic apparatus according to the present embodiment, the alignment and the like described above can be changed according to the on-screen display position of the cursor detected by the position detection unit (not shown). In the present embodiment, a range of a predetermined size is provided on the display screen centering on a display form for input such as a button. When the cursor is in the pixel of the predetermined range, the adjustment defined in the display form which is the center of the predetermined range can be performed via the cursor. That is, by operating the mouse 930 and rotating the wheel 931 in the mouse 930, it is possible to issue an adjustment instruction corresponding to the image of the display area in which the cursor 1002 is positioned. For example, when the cursor is positioned in the display area of the anterior segment image, alignment is performed, when the cursor is positioned in the display area of the fundus image, when the cursor is positioned in the focus position of the fundus and in the display area of the tomographic image. Can adjust the coherence gate position respectively.

  In this case, a manual is selected by the examiner for the mode selection button 1004 for alignment of the measurement screen 1000. Further, each adjustment instruction such as alignment can also be instructed by an operation such as dragging of the mouse 930. Note that after each adjustment such as alignment is completed, the examiner presses the imaging button 1003 to perform desired imaging.

  As described above, the sliders disposed in the vicinity of the image are used to adjust the image quality or the like of the image displayed on the corresponding display screen. The slider 1103 adjusts the position of the optical head 900 in the Z direction with respect to the subject eye 107, the slider 1203 adjusts the focus position, and the slider 1302 adjusts the coherence gate position.

  The adjustment of the focus position is performed by moving the focusing lens 135-3 and the focusing lens 135-5 in the direction of the illustrated arrow along the optical axis in order to adjust the focus on the fundus. These focusing lenses, including the configuration such as a drive system for position control of these, in the present embodiment, the light of the focusing lens serving as a focusing member to obtain the in-focus state of the measurement light with respect to the eye 107 or the fundus The in-focus position changing means is configured to change the on-axis position. Adjustment of the coherence gate position is performed by moving the reflecting mirror 132-4 in the direction of the illustrated arrow along the optical axis so that the tomographic image can be observed at a desired position on the tomographic image display screen 1301. To be done. In the present embodiment, the reflection mirror 132-4 and the configuration for driving the reflection mirror 132-4 on the optical axis constitute an optical path length difference changing unit that changes the optical path length difference between the measurement light and the reference light. In addition, these sliders move the cursor in conjunction with each other when the wheel 931 is operated by the mouse 930 with the cursor 1002 positioned on the respective images.

(Shooting with auto)
First Embodiment
Next, the photographing method of the fundus according to the first embodiment of the present invention will be described using the flowchart of FIG. Here, the case where auto is selected by the mode selection button 1004 for alignment of the measurement screen 1000 will be described.

  First, in step 301, imaging is started. Next, in step 304, alignment which is alignment between the subject eye 107 and the device (optical head 900) is started. The end of this alignment is determined in step 305. If it is determined in step 305 that the alignment is good, the alignment is finished and the flow proceeds to step 306. If it is determined that the alignment is not good, the flow returns to step 304, and this loop continues until it is determined that the alignment is good thereafter. Alternatively, the flow may proceed to step 306 when the alignment becomes good while the alignment is continued without completing the alignment.

  In step 306, focus adjustment (focusing operation) in each of the SLO and OCT optical systems is performed. The focus adjustment described here corresponds to the operation of adjusting the position on the optical axis of each of the focusing lenses 135-3 and 135-5 described above. Next, in step 307, it is determined whether the diopter of the eye to be examined falls within the focus adjustment range or the optical path length change range. If it is determined that it is within the range, the flow proceeds to step 308, and adjustment of one of the measurement light and the reference light is performed. In step 308, the light amount adjustment of the reference light is performed. Next, in step 309, the adjustment of the coherence gate position described above is performed. The determination of the end of the adjustment of the coherence gate position is made at step 310. If it is determined at step 310 that the adjustment is not complete, the flow returns to step 308 and the loop continues until the adjustment is complete. If it is determined that the adjustment is completed, acquisition of tomographic images is started in the subsequent step 311, and imaging is ended in the step 312.

  If it is determined in step 307 that the diopter of the eye to be examined is out of the measurement specification range in the current alignment of the device, the flow proceeds to step 313. In step 313, the examiner is asked whether to change the distance (WD) between the eye to be examined 107 and the optical system (optical head 900) from the initial value (here, 35 mm). If the examiner's operation selects not to change the WD in step 313, the flow proceeds to step 308 and thereafter performs the same operation as the operation described above. Also, if it is selected to change the WD, the flow proceeds to step 314. The operation of this step 313 in this embodiment is an operation to confirm whether or not the relative position with respect to the eye 107 to be inspected by the optical head 900 is to be performed when it is determined that the in-focus state can not be obtained. The operation is performed via the input unit 929, and is shifted to execution by an area functioning as a confirmation unit in the personal computer 925.

  In step 314, from the SLO focus image obtained in step 306, it is calculated how much the WD should be changed from the initial value, and the WD is changed based on the result. The change of WD moves the optical head 900 in a direction (a range of 30 to 35 mm) in which the eye 107 and the optical system approach when the diopter of the eye to be examined is a minus diopter. In addition, in the case of a plasm diopter, the optical head 900 is moved in the direction to go away (in the range of 35 to 40 mm). That is, in the case where the in-focus state can not be obtained, in step 314, depending on the required diopter of the eye to be examined, the relative position is selected to be either separation or approach, and the operation is performed.

  After the optical head 900 is moved and becomes WD corresponding to the eye to be examined, the flow proceeds to step 315. At step 315, if the focus adjustment for the SLO image is not correct, the flow returns to step 314 and continues this loop until the adjustment is complete. When changing the WD in step 314, it is determined that the adjustment has been completed by searching for the peak value of the luminance in the SLO image and determining that the focus has been achieved. After it is determined in step 315 that the adjustment is completed, the flow proceeds to step 308 and thereafter performs the same operation as the operation in the flow described above.

  In step 307 described above, in other words, it is determined whether the in-focus state can be obtained by the position change within the position change range of the focusing lens by the focus position changing means. This determination is performed by the area functioning as the determination means in the personal computer 925. Alternatively, the determination may be whether or not a predetermined tomographic image can be obtained in a range in which the optical path length difference can be changed by the optical path length difference changing unit. In this case, if it is determined that the optical head 900 can not obtain it, the relative position between the subject's eye 107 and the optical head 900 is changed.

  The personal computer 925 also has an area which functions as control means for operating the alignment means such as the stage unit 950 according to the judgment result of the judgment means. Further, more preferably, as described in the present embodiment, the determination unit may determine whether or not the in-focus state can be obtained when the focusing operation is performed after the end of the alignment by the alignment unit. . The control means may move the optical head 900 when it is determined that the in-focus state can not be obtained.

  In addition, although the example which the stage part 950 moves is shown in this embodiment, you may change the position of the to-be-tested eye 107 itself via the jaw stand 323. FIG. Therefore, it is preferable that the alignment means, including this aspect, be interpreted as changing the relative position of the eye 107 to be examined and the optical head 900.

  In the first embodiment, in step 313, the examiner is asked whether to change the WD. However, if the flow is changed in advance by the setting of the apparatus and step 313 is omitted to proceed to step 314, the burden on the examiner can be further reduced.

  In addition, when the WD is changed, so-called “broken” occurs in the SLO image and the OCT image as the amount of change becomes larger. For this reason, it is preferable to change the focus determination range so that the center of the image is weighted according to the change distance. This makes it possible to eliminate the effect of "broken". In addition, when the eye to be examined has a small pupil diameter, "jumping" occurs. For this reason, it is more preferable to calculate the pupil diameter of the subject's eye from the anterior eye image and to weight the focus adjustment range to the center similarly. In the case where the WD changes or when the eye to be examined has a small pupil diameter, "bent" occurs in the image as described above, so in advance, it is calculated how much the amount will be in each case. It is more preferable to reduce the scan range in the X direction (the angle at which the XY scanner 134 swings).

  As described above, in the first embodiment, when the diopter of the eye to be examined is out of the adjustment range of the optical path length changing means, there is a contrast by automatically changing the positional relationship between the eye to be examined and the optical system. A tomographic image can be obtained.

Second Embodiment
The photographing method of the fundus according to the second embodiment of the present invention will be described with reference to the flowchart of FIG.

  In the first embodiment, the flow in photographing in a state in which the diopter of the eye to be examined is not known has been described, but in the present embodiment, the case where the diopter is known in advance will be described. Note that the processes of step 404 to step 412 in the flowchart shown in FIG. 4 are the same as the processes of step 304 to step 312 in the flowchart shown in FIG. 3 described above, so the description of these steps here is omitted. .

  When the diopter of such an eye to be examined is known in advance, the WD initial value is changed in step 403 by inputting the diopter information before the start of measurement as in step 402. By incorporating this step, the steps 307 and 313 to 315, which are the first embodiment, can be omitted, and imaging can be performed in a short time.

  The diopter value may be input via the input unit 929 or may be read out from the hard disk 926. These configurations constitute information input means for inputting information of the eye 107 to be examined in this embodiment. Further, in the present embodiment, the determination means described in the previous embodiment disposed in the personal computer 925 can obtain the in-focus state within the position change range of the focusing lens according to the input information. Will be determined. If it is determined that the relative position between the optical head 900 and the subject's eye 107 is changed to perform alignment, the initial positional relationship is changed.

  As described above, in the present invention, it is possible to select whether to give priority to the viewing angle of the fundus image or to give priority to the contrast of the tomogram in photographing the eye to be examined whose diopter is outside the adjustment range of the optical path length changing means. I have to. As a result, when the view angle is prioritized, the conventional imaging is performed, and when the contrast is prioritized, it is possible to automatically change the relative position between the eye and the optical system. As a result, even when the diopter of the subject's eye exceeds the adjustment range of the ophthalmologic apparatus, it is possible to easily acquire an appropriate tomographic image of the subject's eye.

(Other embodiments)
The present invention is also realized by executing the following processing. That is, software (program) for realizing the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU or the like) of the system or apparatus reads the program. It is a process to execute.

Furthermore, the present invention is not limited to the above-described embodiment, and various modifications and changes can be made without departing from the spirit of the present invention. For example, although the above embodiment describes the case where the test object is an eye, particularly a fundus, the present invention can also be applied to an object to be measured such as skin or an organ other than the eye. In this case, the present invention has an aspect as a medical device such as an endoscope other than the ophthalmologic apparatus. Therefore, it is desirable that the present invention be grasped as an examination device exemplified by an ophthalmologic apparatus, and the eye to be examined be grasped as one aspect of the examination object.
Further, in the above embodiment, an OCT apparatus has been described as an example for which the effects of the present invention are preferably obtained, but the application target of the present invention is not limited to the OCT apparatus. That is, the present invention can be applied to an apparatus for obtaining an image of an object to be inspected which is proved by measurement light.

The optical path 351 forms an OCT optical system as described above, and is for acquiring a tomographic image of the fundus of the eye 107 to be examined. More specifically, an interference signal for forming a tomographic image is obtained. OCT optical system has an optical member disposed on the optical path of the measuring beam, an optical member disposed in the optical path of the reference light, the light source 101, an optical coupler error 131, and the spectrometer 180 for obtaining an interference signal from the interference light. In the present embodiment, the OCT optical system is a tomographic image of the fundus of the eye to be examined 107 based on combined light obtained by combining the return light from the test object irradiated with the measurement light and the reference light corresponding to the measurement light. A tomographic image acquisition unit configured to acquire an image is configured.

Light emitted from the light source 101 is separated as measurement light here is guided to the optical coupler error 131 via optical fibers 131-1 and reaches the optical path of the measuring beam through an optical fiber 131-2. An XY scanner 134, a focusing lens 135-5, and a lens 135-6 are disposed on the optical path of the measurement light reaching the second dichroic mirror 132-2.

Next, the optical path from the light source 101 and the configuration of the reference optical system will be described. Light emitted from the light source 101 is split into the reference beam by the optical coupler error 131, leading to the reference optical system through the optical fiber 131-3. In the reference optical system, a lens 135-5, a dispersion compensating glass 115, and a mirror 132-4 are disposed from the side of the optical fiber 131-3. The above-described optical coupler 131 is connected to single-mode optical fibers 131-1-4 which are connected and integrated with the optical coupler. The reference light path 135-7 passes through the optical fiber 131-4 to the spectroscope 180. These configurations constitute a Michelson interferometer.

On the other hand, the reference light passes through an optical fiber 131-3 and a lens 135-7, and reaches the mirror 132-4 via the dispersion compensation glass 115 inserted for matching the dispersion of the measuring beam and the reference beam is reflected . Then, it returns to the same optical path and reaches the optical coupler 131 again. The measurement light and the reference light are combined by the optical coupler 131 to become interference light (also referred to as combined light). Here, interference occurs when the optical path length of the measurement light and the optical path length of the reference light become substantially the same.

Claims (10)

An image acquisition unit that acquires a tomographic image from interference light in which the return light from the fundus of the subject's eye irradiated with the measurement light interferes with the reference light corresponding to the measurement light;
Optical path length difference changing means for changing the optical path length difference between the optical path length of the measurement light and the optical path length of the reference light by moving the optical path length adjusting member;
Alignment means for changing the relative position between an optical head having a measurement optical system and an anterior segment of the subject's eye to align the optical head with the anterior segment of the subject's eye;
The tomographic image can be obtained by changing the position of the optical path length adjusting member within the changeable range of the optical path length difference changing unit while the optical head and the anterior segment of the subject's eye are aligned. Determining means for determining whether or not
A control unit that operates the alignment unit when it is determined by the determination unit that the tomographic image can not be obtained within the changeable range;
An inspection apparatus comprising: It further comprises an information input means for inputting information of the eye to be examined,
The inspection apparatus according to claim 1, wherein the determination unit determines whether the tomographic image can be obtained according to the information input by the information input unit.   The control unit may further include a confirmation unit that confirms whether the relative position is to be changed by the alignment unit when it is determined that the tomographic image can not be obtained by the determination unit. The inspection apparatus according to claim 1.   The control means performs either of an operation of moving the optical head away from the eye to be examined or an operation of bringing the eye close to the eye according to the diopter of the eye to be examined which is obtained when the in-focus state of the measurement light can not be obtained. The inspection apparatus according to any one of claims 1 to 3, characterized in that   The image acquisition means further comprises focusing position changing means for changing the position of the focusing member in order to obtain the focusing state of the measurement light with respect to the fundus of the eye to be examined. The inspection apparatus according to any one of the above. Tomographic image acquisition means for acquiring a tomographic image of the fundus of the subject's eye based on interference light obtained by causing the reference light corresponding to the measurement light to interfere with the return light from the fundus of the subject's eye irradiated with the measurement light ,
Focusing position changing means for changing the position of the focusing member to obtain the in-focus state of the measurement light with respect to the fundus of the eye to be examined;
Alignment means for changing the relative position between the optical head having the focusing member and the anterior segment of the subject's eye to align the optical head with the anterior segment of the subject's eye;
Optical path length difference changing means for changing the optical path length difference between the measurement light and the reference light;
It is determined that a predetermined tomographic image can not be obtained in a range in which the optical path length difference can be changed by the optical path length difference changing unit in a state in which the optical head and the anterior eye portion of the subject eye are aligned. And control means for changing the relative position by the alignment means;
An inspection apparatus comprising:   The said alignment means changes the distance which is the reference | standard of the said alignment of the said optical head and the anterior ocular segment of the said to-be-tested eye according to the diopter of the said to-be-tested eye. Inspection device. An image acquisition step of acquiring a tomographic image from interference light in which the return light from the fundus of the subject's eye irradiated with the measurement light interferes with the reference light corresponding to the measurement light;
An optical path length difference changing step of changing the optical path length difference between the optical path length of the measurement light and the optical path length of the reference light by moving the optical path length adjusting member;
Alignment means for operating the alignment means to change the relative position between the optical head having the measurement optical system and the anterior segment of the subject's eye to align the optical head with the anterior segment of the subject's eye Process,
The tomographic image can be obtained by changing the position of the optical path length adjustment member within the optical path length change range in the optical path length difference changing step in a state in which the optical head and the anterior segment of the subject eye are aligned. A determination step of determining whether or not
And a control step of operating the alignment unit when it is determined that a tomographic image can not be obtained within the optical path length change range in the determination step. An image acquisition means for acquiring an image of the fundus of the subject's eye irradiated with the measurement light, an optical head having a focusing member for obtaining the in-focus state of the measurement light with respect to the fundus of the subject's eye A control method of an inspection apparatus, comprising: alignment means for changing a relative position with a part; and optical path length difference changing means for changing an optical path length difference between the measurement light and a reference light corresponding to the measurement light ,
An alignment step of aligning the optical head with the anterior segment of the subject's eye using the alignment unit;
It is determined that a predetermined tomographic image can not be obtained in a range in which the optical path length difference can be changed by the optical path length difference changing unit in a state in which the optical head and the anterior eye portion of the subject eye are aligned. And controlling the relative position by the alignment unit.   A program causing a computer to execute each step of the control method of the inspection apparatus according to claim 8 or 9.

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