JP2018143447A - Optical tomographic imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical tomographic imaging apparatus which displays a tomographic image easily viewable to an examiner.SOLUTION: An optical tomographic imaging apparatus 1 comprises: a measurement unit 10 for scanning, using a deflection unit, measurement light from a light source on a scannable range (including at least a range from the posterior pole part to the equator part of an eyeground) and detecting, by a detector 19, an interference between a reflection of the measurement light and reference light); and a controller 30. The controller 30 acquires an OCT image of the eyeground based on a signal from the detector 19 and causes the acquired OCT image to be displayed on a touch-panel monitor 41. When a direction to change at least a transversal display position of the OCT image on the touch-panel monitor 41 is input based on an operation on the touch-panel monitor 41, the controller causes a movement of the OCT image display position at least in a transversal direction.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an optical tomography apparatus that captures tomographic images of a tissue of a subject.

  2. Description of the Related Art Conventionally, an apparatus using an optical coherence tomography (OCT) is known as an apparatus that can take a tomographic image at a predetermined part of a subject. In this apparatus, a tomographic image having a scan line as a cut surface is generated based on return light from the subject by scanning the measurement light on the subject with an arbitrary scan line.

  For example, Patent Document 1 discloses an apparatus that captures a tomographic image at a desired position of an eye to be examined via a probe held by an operator.

JP-A-2015-104582

  In the above apparatus, the top, bottom, left, and right in the tomographic image do not necessarily coincide with the top, bottom, left and right in the real space. In the case of an apparatus of the type disclosed in Patent Document 1, it is considered that the correspondence between top and bottom and left and right in a tomographic image and top and bottom and left and right in real space varies depending on, for example, the orientation of the probe during imaging.

  In addition, even if the top, bottom, left, and right in the tomographic image coincide with the top, bottom, left, and right in the real space, whether or not the state is suitable for observation and diagnosis depends on the photographed part and the preferences of each examiner. It is thought to do.

  The present disclosure has been made in view of the problems of the prior art, and an object thereof is to provide an optical tomography apparatus that displays a tomographic image that can be easily observed by an examiner.

  The optical tomographic imaging apparatus according to the first aspect of the present disclosure uses a range including at least the posterior pole portion to the equator portion of the fundus as a scannable range, and uses the optical scanner to measure light from a light source within the scannable range. The OCT image of the fundus is acquired based on a measurement unit that scans in part and detects interference between the reflected light of the measurement light and the reference light by a detector, and a signal from the detector, and the acquired OCT Control means for displaying an image on a monitor, and an instruction for at least an instruction for changing the display position of the OCT image on the monitor in the transverse direction based on an operation on the operation unit Input means, and when the instruction is input, the display control means determines the display position of the OCT image on the monitor based on the instruction. Even without moving with respect to the transverse direction.

  An optical tomography apparatus according to the second aspect of the present disclosure repeatedly scans measurement light from a light source on a subject via a probe inserted into the subject, and reflects reflected light of the measurement light and reference light. And a measurement unit for detecting the interference by the detector, and whenever the scanning of the measurement light is repeated, a tomographic image of the subject is acquired as an OCT image at any time based on a signal from the detector, and acquired at any time Control means for displaying the OCT image on a monitor as a real-time live image, and an instruction for changing the display position in the live image on the monitor in the transverse direction is an operation for the operation unit. Instruction input means input at least based on the display, and the control means displays the display position of the live image on the monitor when the instruction is input. , Based on the instruction to move with respect to at least the transverse direction.

  According to the apparatus of the present disclosure, there is an effect that a tomographic image that can be easily observed by the examiner is displayed.

1 is a diagram showing a schematic configuration of an optical tomography apparatus and peripheral devices according to a first embodiment. It is an enlarged view of the front-end | tip part vicinity of a probe. It is an example of the tomographic image (two-dimensional OCT data) image | photographed with the optical tomography apparatus, and was represented by the polar coordinate system. It is an example of a tomographic image expressed in an orthogonal coordinate system. It is a figure for demonstrating the state of the front-end | tip part when a fiber is twisted. It is a figure for demonstrating the change operation | movement of the display position of a tomographic image, (a) is a tomographic image image | photographed when a fiber is twisted, (b) is based on the input instruction | indication It is a tomographic image whose display position is corrected. It is a figure which shows schematic structure of the optical tomography apparatus which concerns on 2nd Embodiment. It is an example of the display screen in 2nd Embodiment, (a) is a display example in the initial position of the three-dimensional image of an equatorial part, (b) is a display position correct | amended based on the input instruction | indication. 3 is a display example of a three-dimensional image.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

<First Embodiment>
First, a schematic configuration of an optical tomography apparatus (hereinafter abbreviated as “imaging apparatus”) 1 according to the first embodiment will be described with reference to FIG.

<Device configuration>
The imaging apparatus 1 images two-dimensional OCT data (for example, a tomographic image (B scan image)) of a tissue in a subject using a probe 2 inserted into the subject.

  Hereinafter, as a specific example, the imaging device 1 is assumed to be an ophthalmic imaging device. That is, a tomographic image of the internal tissue (for example, retina) of the eye E is imaged by the imaging device 1. However, the present disclosure can also be applied to an apparatus that captures tomographic images of subjects other than the eyes (for example, internal organs, ears, etc.). The photographing apparatus 1 includes a measurement unit 10 and a control unit 30.

  The measurement unit 10 includes an optical tomography (OCT: Optical Coherence Tomography) configuration (for example, an interference optical system). The measurement unit 10 of the first embodiment includes a measurement light source 11, an aiming light source 12, a coupler 13, a coupler 14, a reference optical system 15, a mounting unit 16, a fiber rotation motor 18, a detector (light receiving element) 19, and an optical path length changing unit. 20.

  The measurement light source 11 emits light for acquiring two-dimensional OCT data (for example, a tomographic image and an angiography in a cross-sectional direction). As an example, the imaging apparatus 1 includes the measurement light source 11 that can change the wavelength of the emitted laser light at high speed, and thereby obtains two-dimensional OCT data by sweep-source OCT (SS-OCT) measurement. The measurement light source 11 includes a laser medium, a resonator, a wavelength selection filter, and the like. As the wavelength selection filter, for example, a combination of a diffraction grating and a polygon mirror, or a filter using a Fabry-Perot etalon can be employed.

  The aiming light source 12 emits aiming light that is visible light to indicate the irradiation position of the measurement light (that is, the acquisition position of the two-dimensional OCT data).

  The coupler 13 combines the light emitted from the measurement light source 11 and the aiming light emitted from the aiming light source 12, and matches the optical axes of the two lights. The coupler 14 divides the light incident from the coupler 13 into measurement light (sample light) and reference light. The measurement light is guided to the probe 2 mounted on the mounting unit 16. The reference light is guided to the reference optical system 15. Further, the coupler 14 combines the measurement light reflected by the eye E (reflection measurement light) and the reference light generated by the reference optical system 15 to generate interference light. The coupler 14 causes the detector 19 to receive the generated interference light.

  The reference optical system 15 returns the reference light guided from the coupler 14 to the coupler 14 again. The reference optical system 15 may be a reflection optical system (Japanese Patent Laid-Open No. 2014-188276) or a transmission optical system (Japanese Patent Laid-Open No. 2010-220774).

  The detector 19 detects an interference state between the reflected measurement light and the reference light. In other words, the detector 19 detects the interference signal of the interference light generated by the coupler 14. More specifically, in the case of Fourier domain OCT, the spectral intensity of the interference light is detected by the detector 19, and a depth profile (A scan signal) in a predetermined range is obtained by Fourier transform on the spectral intensity data. Further, by collecting depth profiles for each scanning position and arranging the depth profiles, two-dimensional OCT data (for example, B scan image see FIGS. 3 and 4) is formed.

  As described above, SS-OCT is adopted for the imaging apparatus 1 of the first embodiment. However, various types of OCT can be adopted for the imaging apparatus 1. For example, any of Spectral-domain OCT (SD-OCT), Time-domain OCT (TD-OCT), and the like may be employed in the imaging apparatus 1. When employing SS-OCT, it is desirable to employ a balanced detector having a plurality of light receiving elements as the detector 19. When the balance detector is used, the imaging apparatus 1 can obtain the difference between the interference signals from the plurality of light receiving elements, and reduce unnecessary noise included in the interference signals. As a result, the quality of the two-dimensional OCT data is improved.

  A rear end portion (base end portion) of the fiber 4 in the probe 2 is detachably attached to the attachment portion (for example, connector) 16. When the probe 2 is attached to the attachment part 16, the probe 2 is connected to the measurement light guide path (for example, the fiber 4 in the measurement part 10) divided by the coupler 14.

  A fiber rotation motor (hereinafter abbreviated as “motor”) 18 can rotate the mounting portion 16 to which the fiber 4 is mounted about the axis of the fiber 4. That is, the motor 18 rotates the fiber 4 by rotating the mounting portion 16. As a result, in the first embodiment, measurement light and aiming light are scanned (details will be described later). The motor 18 is provided with a rotation detection sensor 18a. The rotation detection sensor 18a detects the rotation of the fiber 4 at the rear end for each rotation and outputs a signal to the control unit 30 for each detection (that is, for each rotation). The signal from the rotation detection sensor 18a is used to determine the generation start timing of each two-dimensional OCT data (for example, B scan image). That is, one scan is performed between two signals that are continuously output as the fiber 4 rotates.

  Here, the probe 2 attached to the attachment part 16 will be described with reference to FIGS. 1 and 2. The probe 2 includes a probe main body 3 and a fiber 4. The probe body 3 includes a hand piece 5 and a needle 6.

  The fiber 4 is inserted into the probe main body 3 and guides the measurement light and aiming light guided from the coupler 14 of the measurement unit 10 to the tip of the needle 6 from the outside of the probe main body 3.

  The fiber 4 is covered with a torque coil (not shown). The torque coil is an example of a torque transmission unit, and transmits torque from the motor 18 to the fiber 4. Thereby, the fiber 4 is rotated together with the torque coil. The fiber 4 and the torque coil 7 rotate freely with respect to the handpiece 5.

  The handpiece 5 is a substantially cylindrical member that is gripped by an operator (for example, an examiner, an operator, etc.). The needle 6 is provided at the tip of the handpiece 5 and has an outer diameter smaller than the outer diameter of the handpiece 5. The tip of the needle 6 is inserted into the subject (for example, the eye E). The fiber 4 is connected to the rear end of the handpiece 5 and extends to the tip of the needle 6. The probe 2 can emit each light from the tip while scanning the measurement light and aiming light guided by the fiber 4.

  Here, with reference to FIG. 2, the structure of the front-end | tip part in the probe 2 is demonstrated in detail. A light shielding member 61, an outer cylinder 66, a holding portion 68, a deflection portion 71, and the like are provided at the distal end portion of the needle 6.

  The light shielding member 61 surrounds the periphery of the fiber 4 (particularly, the periphery of the holding unit 68 and the deflecting unit 71). The shape of the light shielding member 61 illustrated in FIG. 2 is substantially cylindrical. The light blocking member 61 is formed of a material that blocks measurement light and aiming light. A notch 62 (or opening) having a predetermined width in the scanning direction (direction around the axis) of the measurement light and aiming light is provided in the vicinity of the portion where the deflection unit 71 is located in the axial direction of the light shielding member 61. Is formed. The light emitted from the deflecting unit 71 is transmitted to the outside in the region 63 inside the notch 62 (hereinafter referred to as “transmission region 63”), but the region 64 where the notch 62 is not formed (hereinafter referred to as “transmission region 63”). In the “light shielding region 64”), light is shielded by the light shielding member 61.

  The inner surface of the light shielding member 61 may be roughened. That is, a large number of fine irregularities may be formed on the inner surface. In this case, in the light shielding region 64, the light irradiated on the inner surface of the light shielding member 61 is scattered. Accordingly, the reflected light reflected by the light shielding region 64 does not return to the deflecting unit 71 as compared with the case where the inner side of the light shielding member 61 hardly scatters light (for example, when the inner surface is mirror-finished). The possibility decreases. That is, when mirror processing or the like is performed, when light is reflected in a direction different from that of the deflecting unit 71, no reflected light is incident on the deflecting unit 71. When the reflected light is scattered, the reflected light easily returns to the deflecting unit 71. Therefore, the imaging apparatus 1 can perform more reliable detection using the reflected light reflected by the light shielding region 64 when detecting that the measurement light is irradiated on the light shielding region 64.

  In addition, although the shape of the transmissive area | region 63 of this embodiment is a substantially rectangular shape, it cannot be overemphasized that the magnitude | size of the transmissive area | region 63, a shape, a number, etc. can be changed. In addition, a specific method for forming the transmission region 63 and the light shielding region 64 can be changed. For example, the light-transmitting region 63 and the light-shielding region 64 may be formed by manufacturing the light-shielding member 61 by combining a material that transmits measurement light and aiming light and a material that shields light.

  The outer cylinder 66 is made of a material that transmits measurement light and aiming light, and closes the outside of the light shielding member 61. Therefore, the outer cylinder 66 allows light to pass between the inside and the outside of the transmission region 63 while preventing blood, vitreous tissue and the like from entering inside. The outer cylinder 66 may be positioned inside the light shielding member 61.

  The holding portion 68 is a substantially cylindrical member having an outer shape, and is fixed to the light shielding member 61. An insertion hole 69 through which the fiber 4 is inserted in a rotatable state is formed in the axial center portion of the holding portion 68. The holding unit 68 holds the fiber 4 in a rotatable manner in a state where the position of the axis of the fiber 4 with respect to the light shielding member 61 is fixed.

  The deflection unit 71 is provided at the tip of the fiber 4. The deflecting unit 71 deflects the light emitted from the tip of the fiber 4. The light deflected by the deflecting unit 71 is irradiated to the tissue of the subject when passing through the transmission region 63. In the present embodiment, the light deflected by the deflecting unit 71 is collected at a predetermined distance. The deflecting unit 71 may be, for example, a ball lens or a prism. The deflecting unit 71 receives reflected measurement light reflected by the tissue and makes it incident on the fiber 4. The deflecting unit 71 of this embodiment deflects light at an angle of about 70 degrees with respect to the axial direction of the fiber 4, but the angle of deflection can be changed as appropriate. Note that a shaft 73 for suppressing twisting of the fiber 4 and the like is provided on the outer periphery of a portion of the fiber 4 on the rear end side of the holding portion 68. In the present embodiment, the motor 18 rotates the deflecting unit 71 together with the fiber 4, whereby the measurement light (and aiming light) is scanned. That is, the “optical scanner” in the present embodiment includes at least the motor 18 and the deflecting unit 71.

  In this embodiment, in a state where the tip of the probe 2 is inserted into the eyeball, the measurement light irradiated and scanned within a certain range from the tip of the probe 2 is irradiated to a desired position in the eyeball. A person can obtain two-dimensional OCT data at a desired position in the eyeball by adjusting the position of the probe 2. The imaging apparatus 1 has a substantially scannable area in the entire eyeball, and each tomographic image is an image of a part of the scannable range. That is, the scannable range includes the posterior pole portion, the equator portion, the anterior eye portion, and the like of the fundus. For example, by arranging the probe 2 at a position where the measurement light is applied to the posterior pole portion of the fundus, a tomographic image at the posterior pole portion can be taken and the equator portion is irradiated. By arranging the probe 2 at the position, a tomographic image at the equator can be taken. Note that the “equator” does not necessarily include an area on the equator, but may be an area near the equator.

  Note that the imaging apparatus 1 may include various configurations such as an optical system for adjusting the focus of the measurement light in the measurement unit 10 or the probe 2. These detailed explanations are omitted.

  Next, the control system of the apparatus will be described with reference to FIG. The control unit 30 includes a CPU (processor) 31, a RAM 32, a ROM 33, a nonvolatile memory 34, and the like. The CPU 31 controls the photographing apparatus 1 and peripheral devices. The RAM 32 temporarily stores various information. The ROM 33 stores various programs, initial values, and the like. The nonvolatile memory 34 is a non-transitory storage medium that can retain stored contents even when power supply is interrupted. For example, a hard disk drive, a flash ROM, and a USB memory that is detachably attached to the photographing apparatus 1 can be used as the nonvolatile memory 34. The nonvolatile memory 34 stores a program for controlling each part of the apparatus. The nonvolatile memory 34 stores various information such as a captured tomographic image.

  In the present embodiment, a personal computer (hereinafter referred to as “PC”) connected to the measurement unit 10 is used as the control unit 30. However, the measurement unit 10 and the control unit 30 may be provided in one device without using a PC. The control unit 30 may be configured by a plurality of control units (that is, a plurality of processors). For example, the control unit 30 of the photographing apparatus 1 may be configured by a first control unit provided in the PC and a second control unit provided in the measurement unit 10. In this case, for example, the first control unit of the PC may instruct the second control unit to start and end shooting based on the operation of the operation unit connected to the PC. The second control unit may control the operations of the measurement light source 11, the aiming light source 12, the motor 18 and the like according to instructions from the first control unit. Further, the image generation processing based on the interference signal may be performed by either the first control unit or the second control unit.

  In the present embodiment, the control unit 30 also serves as an image forming unit that forms a tomographic image based on a signal from the detector 19. In this case, for example, the control unit 30 performs a Fourier transform on the signal from the detector 19 to obtain a depth profile (A scan), and arranges the obtained depth profiles for each scanning position to obtain 2 Dimension OCT data (for example, B scan image) is generated. In this embodiment, since scanning is performed around the axis of the probe 2, each depth profile is expressed by polar coordinates where the origin is placed on the axis of the probe 2. The control unit 30 may acquire the two-dimensional OCT data of the subject expressed by the polar coordinates. The two-dimensional OCT data may be tomographic image data expressed by polar coordinates, or may be tomographic image data expressed by orthogonal coordinates. For a conversion method from polar coordinate data to orthogonal coordinate data, see, for example, Japanese Patent Application Laid-Open No. 2015-104582 by the present applicant.

  The control unit 30 is electrically connected to a display unit, an operation unit, and peripheral devices such as a surgical microscope 46. A tomographic image, which will be described later, is displayed on the display unit. The display unit may be, for example, a PC display, a display dedicated to the photographing apparatus 1, or may be other than that. A plurality of displays may be used in combination.

  The operation unit is a device for recognizing various operation instructions. As the operation unit, for example, at least one of a mouse, a joystick, a keyboard, a touch panel, and the like may be used. These may be operated by an assistant who assists the work from a location away from the worker.

  In addition, for example, as an operation unit to which an operation instruction from an operator is input, a switch (not shown) is provided in the probe 2, a voice recognition device for recognizing the voice from the operator, A recognition device may be provided.

  Below, the Example to which the touch panel monitor 41 was applied as a device which serves as a display part and an operation part is shown. In this embodiment, the display of the touch panel monitor 41 is used as one of the display units, and the touch panel stacked with the display is used as one of the operation units. When it is assumed that the device is used during the operation like the imaging device 1, it can be considered that it is desirable to use the touch panel as the operation unit for the operator from the viewpoint of easy cleaning.

  The touch panel monitor 41 may be a tablet PC. In this case, other hardware resources of the tablet PC can be used as a part or all of the hardware resources of the photographing apparatus 1. For example, a processor built in the tablet PC can be used as at least a part of the control unit in the photographing apparatus 1.

  The surgical microscope 46 magnifies and displays the inside of the subject (the eye E in this embodiment) during surgery, during diagnosis, or during these exercises (taken and magnified in this embodiment). The operator performs surgery, diagnosis, or training thereof while looking into the surgical microscope 46 (in the present embodiment, these are collectively referred to as “work”). Moreover, in this embodiment, the control part 30 can acquire the image image | photographed with the surgical microscope 46, and can display it on a display part. During the work, the worker's assistants and the like can confirm the work status and the like by checking the image displayed on the display unit. Note that the present disclosure can be realized without using the surgical microscope 46. For example, an observation optical system for capturing an image inside the subject may be provided in the measurement unit 10. In this case, the operator can work while confirming the image photographed by the observation optical system. Further, the present disclosure can be applied even when the operator gazes near the tip of the probe 2 with the naked eye.

<Description of operation>
With reference to FIGS. 3 to 6, the operation of the photographing apparatus 1 will be described.

<Generation and display of tomographic images>
The control unit 30 turns on the measurement light source 11 to irradiate the measurement light from the deflection unit 71 and controls the motor 18 to rotate the fiber 4 at a constant speed. Thereby, the measurement light is scanned on the eye E. The control unit 30 acquires two-dimensional OCT data (for example, a B-scan image) based on a signal output from the detector 19 as the measurement light is scanned. For example, the two-dimensional OCT data may be formed based on a signal output from the detector 19 as a result of scanning the measurement light from one end to the other end of the transmission region 63. The generated two-dimensional OCT data may be displayed on the display unit as a tomographic image. In this case, the control unit 30 may display the moving image based on the tomographic image on the display unit. The moving image may be a live image captured in substantially real time. The live image is useful for grasping the state of the eye to be examined during work.

  Here, FIG. 3 shows an example of two-dimensional OCT data acquired by the apparatus having the above configuration. FIG. 3 is a tomographic image expressed in polar coordinates. Reference numeral 101 indicates an image of the subject (fundus), and reference numeral 105 indicates a reflected image of the light shielding member 61. Reference numeral 110 indicates a region where an image of the subject is effectively acquired. The region 110 can be detected as, for example, between the edges of the light shielding member 61 in the transverse direction. Such a tomographic image is formed by obtaining a depth profile for each A scan and arranging the depth profiles in the transverse direction.

  In addition, the control unit 30 can generate a tomographic image expressed in orthogonal coordinates by coordinate conversion of the tomographic image expressed in polar coordinates (see FIG. 4). In this case, coordinate conversion may be performed with reference to the rotation axis of the polarization unit 71 (also referred to as the “axis of the probe 2”). For more detailed contents of this method, refer to “Japanese Unexamined Patent Application Publication No. 2015-104582 (documents cited above as Patent Document 1)” by the present applicant.

  Further, in this embodiment, two-dimensional OCT data for one frame (one sheet) is constructed for each rotation of the fiber 4. More specifically, every time the rotation detection sensor 18a provided in the motor 18 detects one rotation of the fiber 4, a detection signal is output. Based on the output timing of this detection signal, the start point and end point of scanning effective for obtaining two-dimensional OCT data are set (see FIG. 5A). That is, the capture range in the two-dimensional OCT data for one frame is set. The time when <time a> has elapsed from the output timing of the detection signal is the “start point”, and the time when <time a> + <time b> has elapsed from the output timing of the detection signal is the “end point”. It is. In this case, two-dimensional OCT data is formed based on the scanning of the measurement light performed during <time b>. For this reason, the above “start point” is synonymous with a two-dimensional OCT data acquisition start trigger. Note that <time a> + <time b> is shorter than the scanning period (that is, the time per rotation of the motor 18).

  Hereinafter, <time a> is also referred to as “trigger standby time”.

  By the way, even if the motor 18 is rotating uniformly, twisting of the fiber 4 causes unevenness in the rotation speed on the tip end side (that is, the probe 2 side) of the fiber 4 (hereinafter referred to as “rotation unevenness”). Or a delay (hereinafter referred to as “rotation delay”) with respect to the rotation of the motor 18 (see FIG. 5B). At this time, the degree of rotation unevenness and rotation delay changes with the change in the bending method of the fiber 4 during work, and is difficult to stabilize.

  Because of the above-described rotation unevenness and rotation delay, the relationship between the period during which the measurement light scans the subject through the transmission region 63 and the output timing of the detection signal is not constant during the operation. As a result, the range corresponding to the transmission region 63 (that is, the range in which an image of the subject can be generated) may change from time to time with respect to the capture range in the two-dimensional OCT data. Then, in one OCT image, the position of the region 110 where the subject is depicted (mainly the position in the transverse direction) varies (see, for example, FIG. 6A).

  Further, in the imaging apparatus 1 in the present embodiment, the operator freely moves the probe 2 with respect to the subject, and a tomographic image of the subject is taken. As a result, the direction of the tomographic image displayed as an image may be different from the direction assumed by the examiner. When photographing the inside of the eyeball, for example, the case where the equator part is photographed and the case where the rear pole part is photographed are distinguished, and the depth direction at the photographing part is one direction on the screen (for example, the vertical direction). When the display is performed in conformity with (), the examiner who performs observation / diagnosis using the tomographic image may feel uncomfortable.

<Adjusting the display position>
On the other hand, in the present embodiment, the display position of the tomographic image on the touch panel monitor 41 is changed with respect to the transverse direction of the tomographic image based on an instruction input via the operation unit (here, the touch panel monitor 41). The The display position changing process may be a process for controlling the length of <time a> or an image process for changing the display position of the tomographic image. A combination of both may be used.

  Note that these display position changing processes can also be referred to as the above-described <time a> correction processes.

  When the length of <time a> is controlled (that is, change control), the display position is changed in a tomographic image captured thereafter. On the other hand, when the display position of the tomographic image is changed by image processing, the display position can be changed not only for the tomographic image captured after that but also for the already captured tomographic image.

  Below, the case where the live image by the tomographic image expressed by a rectangular coordinate is displayed on a display part is demonstrated to an example, and each correction process and operation for a correction process are demonstrated. In this case, for example, the tomographic image is displayed in a circular region (indicated by reference numeral 41a in FIG. 6) set on the screen of the display unit. The center of the circular area coincides with the origin of the orthogonal coordinates. The change of the display position of the tomographic image may be realized by turning around the origin of the orthogonal coordinates. Thereby, the display position is changed with respect to the transverse direction. As described above, in the following embodiments, it is assumed that the touch panel monitor 41 serves as both a display unit and an operation unit.

<Operation input>
In the present embodiment, in a state where a tomographic image is displayed on the display unit, a display position correction amount (<time a> correction amount) is input based on an operation on the operation unit. The correction amount may be input as a displacement amount of the display position.

  For example, when the display position of the tomographic image is turned around the origin of the orthogonal coordinates, the displacement amount may be input as the turning angle.

  Here, several input methods using the touch panel monitor 41 are illustrated.

  For example, when the examiner operates the touch panel 41, an instruction regarding the target position of the transition may be input to the apparatus. As a specific example, by tapping an arbitrary position on the region 41a, the tapped position may be input as the target position. Then, the display position of the tomographic image on the touch panel monitor 41 is displaced so that the reference position, which is a predetermined position in the tomographic image, is moved to the tapped position (FIG. 6 (a) → FIG. 6 ( b)). In this case, the reference position may be automatically detected from the tomographic image by the control unit 30. For example, the position of a meridian that bisects the region 110 approximately equally is detected as a reference position from the tomographic image, and the tomographic image is rotated so that the meridian is displaced to the tapped position (that is, the target position). You may let them. The meridian may be detected as, for example, the center position of the region where the reflection image 120 of the light shielding unit 63 is missing and the meridian passing through the origin. Alternatively, it may be detected as an image center of gravity of the reflected image 101 of the subject and a meridian passing through the origin.

  Further, for example, when the examiner operates the touch panel 41, an instruction regarding the displacement amount of the display position may be input to the apparatus.

  When the tomographic image is expressed in an orthogonal coordinate system, the displacement amount may be an angle centered on the origin of the orthogonal coordinate system (here, the axis of the probe 2). In other words, the display position displacement amount (correction amount of <time a>) is input by the operation of designating the angle.

  At this time, for example, the displacement amount may be an input value of flick / swipe / drag to the touch panel. For example, an angle between the start point and the end point of the drag (a rotation component around the origin of the orthogonal coordinates) may be input to the control unit 30 as an input value of the correction amount. For example, when a flick / swipe / drag of 90 ° (1/4 rotation) is input around the origin, the tomographic image is rotated 90 °. The speed of operation is not limited to this, and the correction amount may be considered. The tomographic image in a state where the display position is changed may be stored in the nonvolatile memory 34.

  As another operation method, for example, the target position of the displacement is predetermined on the screen, and the position touched by the examiner is moved to the predetermined target position. Good.

  Further, for example, when a position away from the reference position is touched by the examiner, the tomographic image may be moved (rotated) so that the reference position approaches the touched position. In this case, the display position may be displaced larger (or more quickly) as the touched position is farther from the reference position.

  As a result of the above correction, it is possible to display a tomographic image in which the influence of rotation unevenness and rotation delay at the tip of the fiber 4 is suppressed. In addition, it is possible to display a tomographic image in a direction in which the examiner can easily grasp the structure of the subject.

  In addition, the control unit 30 may change the display position of the tomographic image with respect to the depth direction based on an instruction input via the operation unit.

  When the touch panel monitor 41 is used, an instruction to change the display position in the depth direction may be input by inputting flick / swipe / drag in the radial direction on the tomographic image.

  When a tomographic image is displayed in the orthogonal coordinate system, when the display position is changed in the depth direction, the reflected image 105 of the light shielding region 63 and the reflected image 101 of the subject are moved in the radial direction. , Enlarged or reduced. The change of the display position in the depth direction may be realized by image processing (coordinate conversion), or may be made by changing the optical path length difference between the measurement light and the reference light.

  Further, the control unit 30 may change the display magnification of the tomographic image based on an instruction input via the operation unit. At least an enlarged display may be possible. That is, in the state shown in FIG. 6, a circular area 41a is set on the monitor, but the area 110 on which the subject image 101 is displayed is only a part of the area. Therefore, it is considered that the whole or a part of the region 110 is enlarged and displayed on the screen, so that the structure of the subject can be easily grasped using the image 101 of the subject. In the case of enlarged display, it is sufficient that a part of the area 41a is included on the screen, and it is not necessary that the entire area 41a is included.

  When the touch panel monitor 41 is used, the control unit 30 may perform enlargement / reduction of the tomographic image around the operation input position by inputting pinch-out and pinch-in on the tomographic image.

Second Embodiment
Next, a second embodiment will be described with reference to FIGS. In the description of the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and detailed description thereof is omitted. An optical tomographic imaging apparatus 200 (hereinafter abbreviated as imaging apparatus 200) according to the second embodiment is a stationary ophthalmic OCT apparatus. That is, a tomographic image of the eye to be examined is taken with the eye to be examined facing the examination window of the apparatus main body (measurement unit 210) arranged on the table. The imaging apparatus 200 can capture a tomographic image over a wide range of the fundus, for example, the imaging range is from the rear pole to the equator.

<Device configuration>
As shown in FIG. 7, the photographing apparatus 200 mainly includes a measurement unit 210 and a control unit 30. The measurement unit 210 includes main optical systems. For example, the optical scanner 230 and the objective optical system 240 may be included in the measurement unit 210. Further, the light source 11, the reference optical system 15, the detector 19, and the like may be included in the measurement unit 210. Similarly to the example of the first embodiment, in the example illustrated in FIG. 7, the photographing device 200 is provided with a touch panel monitor 41 that also serves as a display unit and an operation unit.

  The optical scanner 230 may be a scanner having two or more degrees of freedom in the scanning direction. For example, a plurality of scanners having different scanning directions may be arranged in series. In the following embodiment, two galvanometer mirrors whose scanning directions are orthogonal to each other are used as the optical scanner 230. In the second embodiment, by controlling the direction of each galvanometer mirror, scanning of the measurement light with respect to an arbitrary scan line may be realized in a scannable range including at least the rear pole portion and the equator portion. Then, a tomographic image in an arbitrary campaign line may be taken.

  When the degree of freedom in the scanning direction is 2 or more, the optical scanner 230 can scan the measurement light two-dimensionally on the fundus. As an example of the two-dimensional scan, for example, a raster scan or a Lissajous scan may be used. As a result, based on the signal output from the detector 19, the control unit 30 may form a three-dimensional image of the fundus. Here, the control unit 30 displays the three-dimensional image as a still image. However, the present invention is not limited to this, and the control unit 30 may continuously generate a three-dimensional image and display it as a moving image.

  Note that the shooting range, resolution, and shooting time of a 3D image are in a trade-off relationship with each other, and if the shooting time is prolonged, it becomes easier to be affected by eye movements and blinks. Shooting at once may not be practical. Therefore, in the photographing apparatus 200, the two-dimensional scanning of the measurement light with respect to the rear pole part and the two-dimensional scanning with respect to the equator part are separately performed with different scanning ranges of the optical scanner 230, and each part is separately three-dimensionally scanned. Get an image.

  The objective optical system 240 may be configured with a mirror system or a lens system. In order to irradiate the measurement light up to the equator, a relatively large lens or a mirror (for example, a concave mirror) may be disposed as the objective optical system 240 immediately before the eye to be examined. The objective optical system 240 forms a turning point R of the measurement light at a position conjugate with the optical scanner 230 with respect to the objective optical system 240. In the eyeball, the measurement light is turned around the turning point R. Note that the working distance of the apparatus is preferably set such that, for example, the turning point R of the measurement light is located at the center of the pupil.

<Operation>
Hereinafter, operations related to display of a three-dimensional image photographed by the photographing apparatus 200 will be mainly described with reference to FIG.

  In the second embodiment, the control unit 30 displays the captured three-dimensional image 300 on the touch panel monitor 41 by expressing it in an orthogonal coordinate system with a predetermined position in the eyeball as the origin. The position of the origin of the orthogonal coordinate system may be, for example, the center of the eyeball. However, the present invention is not necessarily limited to this, and the tomographic image may be expressed with the position of the turning point (that is, the pupil center) as the origin position.

  The touch panel monitor 41 may display a graphic imitating the eyeball together with the three-dimensional image 300. For example, in FIG. 8, an eyeball model image 310 showing a predetermined cut surface passing through the corneal apex is displayed together with the three-dimensional image 300. The eyeball model image 310 in FIG. 8 is a graphic showing the eyeball in a planar manner, but is not necessarily limited thereto, and may be a graphic representing the eyeball three-dimensionally.

  On the eyeball model image 310, a display 320 that emphasizes the shooting position of the three-dimensional image 300 may be performed. In this case, the 3D image 300 may be superimposed on the shooting position of the 3D image 300 on the eyeball model image 310. Thereby, it is easy for the examiner to grasp which position of the three-dimensional image 300 is taken in the eye to be examined.

  The eyeball model image 310 is preferably one that can identify the shooting position of the three-dimensional image 300. For example, as shown in FIG. 8, the imaging position of the three-dimensional image 300 can be identified based on the position of the cornea portion in the eyeball model image 310. For example, information indicating the position of each part in the eyeball model image 310 may be displayed in association with the eyeball model image 310. For example, an index indicating the position of the rear pole part and the position of the equator part may be shown in association with the eyeball model image 310.

  In the second embodiment, the control unit 30 acquires information related to the shooting position of the three-dimensional image 300 in order to specify the region emphasized as the shooting position of the three-dimensional image 300 on the eyeball model image 310. This information may be information indicating the scanning range of the optical scanner 230 at the time of shooting, for example. Further, for example, the integrated image obtained by integrating the three-dimensional image 300 in the depth direction may be matched with the fundus front image obtained by another modality, and acquired based on the matching result. For example, in recent years, a scanning laser ophthalmoscope (SLO) that can capture a range including the posterior pole to the equator as a single fundus front image has been proposed, and the fundus front image captured by such an apparatus. On the other hand, the integrated image of the three-dimensional image 300 can be matched, and information on the shooting position can be acquired based on the matching result.

  As illustrated in FIG. 8A, the control unit 30 determines the initial position at which the three-dimensional image 300 is displayed on the touch panel monitor 41 based on the information regarding the photographing position of the three-dimensional image 300 acquired in advance. It may be set. For example, the orientation of at least the three-dimensional image 300 may be displayed after being adjusted according to the positional relationship between the eyeball center and the photographing position. For example, as shown in FIG. 8A, the three-dimensional image 300 in which the equator is photographed is displayed with the direction perpendicular to the surface of each layer of the fundus approximately matching the horizontal direction on the touch panel monitor 41. The three-dimensional image 300 in which the rear pole portion is photographed is displayed such that the direction perpendicular to the surface of each layer of the fundus is substantially coincident with the vertical direction on the touch panel monitor 41.

<Change display position>
Also in the second embodiment, the display position of the three-dimensional image on the touch panel monitor 41 is changed with respect to the transverse direction of the tomographic image based on an instruction input via the operation unit (here, the touch panel monitor 41). . In this case, as described above, the display position of the three-dimensional image 300 may be changeable from the initial position set according to the positional relationship between the eyeball center and the imaging region. Thus, the three-dimensional image 300 can be observed by changing the orientation so that the examiner can easily observe. Further, the eyeball model image 310 may be rotated in conjunction with the movement of the display position of the three-dimensional image 300. That is, the shooting position and orientation of the three-dimensional image 300 shown in the eyeball model image 310 are matched with the position and orientation of the three-dimensional image 300 on the touch panel monitor 41 (see FIG. 8B).

  In the second embodiment, an operation performed on the touch panel monitor 41 to change the display position may be input via an OCT image (that is, a three-dimensional image here) or an eyeball model. It may be input via the image 310. That is, when a position on the eyeball model image 310 is touched, the reference position set in advance in the eyeball model image 310 is moved to the touched position, and the display position of the three-dimensional image 300 changes accordingly. To do.

  As mentioned above, although this indication was explained based on an embodiment, it is not necessarily restricted to this and this indication contains various modifications to the above-mentioned embodiment.

  For example, in the second embodiment, a case where a three-dimensional image is mainly displayed has been described, but a two-dimensional OCT image may be applied instead of the three-dimensional image. The three-dimensional image and the two-dimensional OCT image are not limited to still images, and may be moving images such as live images.

  Further, for example, in the second embodiment, the case where the initial position where the three-dimensional image is displayed is changed according to the imaging region of the fundus is described, but the initial position is always constant regardless of the imaging region. There may be. For example, the direction perpendicular to the surface of each layer of the fundus may be displayed so as to be substantially coincident with the vertical direction on the touch panel monitor 41. In this case, the examiner may change the display position of the three-dimensional image in accordance with the imaging region, which may make it easier to grasp the structure of the imaging region.

DESCRIPTION OF SYMBOLS 1 Optical tomography apparatus 2 Probe 11 Light source 18 Motor 19 Detector 30 Control part 41 Touch panel monitor 71 Deflection part E Eye to be examined

Claims (14)

The range including at least the posterior pole portion to the equator portion of the fundus is scanned as a scannable range, the measurement light from the light source is scanned in a part of the scannable range using an optical scanner, and the reflected light of the measurement light and the reference light A measurement unit for detecting interference with the detector,
Control means for acquiring an OCT image of the fundus based on a signal from the detector and displaying the acquired OCT image on a monitor;
An instruction input means for inputting at least an instruction for changing the display position of the OCT image on the monitor in the transverse direction based on an operation on the operation unit;
The display control means is an optical tomographic imaging apparatus for moving the display position of the OCT image on the monitor in at least the transverse direction based on the instruction when the instruction is input. The control means scans the measurement light repeatedly in a certain scanning range using the optical scanner, acquires a moving image composed of OCT images based on each scanning,
The optical tomographic imaging apparatus according to claim 1, further comprising displaying a moving image on the monitor and moving a display position of the moving image on the monitor based on the instruction.   The optical tomographic imaging apparatus according to claim 2, wherein the moving image is a live image acquired in real time. The measurement unit irradiates the tissue of the subject with the measurement light via a probe inserted into the subject and provided with the optical scanner,
The optical tomography apparatus according to claim 1, wherein the control unit acquires a tomographic image of the subject as the OCT image. The measurement unit irradiates the tissue of the subject with the measurement light via an objective optical system housed in a stationary housing.
Furthermore,
The optical tomographic imaging apparatus according to claim 1, further comprising a changing unit that changes a region in which the measurement light is scanned to an arbitrary position in a scannable range.   The control means obtains a three-dimensional image of the fundus as an OCT image based on a signal from the detector by two-dimensionally scanning the measurement light with the optical scanner in a part of the scannable range. 6. The optical tomographic imaging apparatus according to claim 5, wherein the display position of the three-dimensional image on the monitor is moved with respect to at least the transverse direction based on the instruction.   The control means displays the three-dimensional image on the monitor expressed in an orthogonal coordinate system with a predetermined position in the eyeball as the origin, and when the instruction is input, the control means displays the 3D image on the monitor. The optical tomographic imaging apparatus according to claim 6, wherein a dimensional image is rotated based on the instruction.   The optical tomography apparatus according to claim 7, wherein the control unit represents the three-dimensional image in an orthogonal coordinate system in which an eyeball center is the predetermined position in the eyeball, and displays the three-dimensional image on the monitor. A measurement unit that repeatedly scans the measurement light from the light source on the subject via a probe inserted into the subject, and detects interference between the reflected light of the measurement light and the reference light by a detector;
Each time scanning of the measurement light is repeated, a tomographic image of the subject is acquired as needed based on a signal from the detector as an OCT image, and the OCT image acquired as needed is displayed on a monitor as a real-time live image. Control means to display;
An instruction input means for inputting at least an instruction for changing a display position in the live image on the monitor in the transverse direction based on an operation on an operation unit;
The said control means is an optical tomography apparatus which, when the said instruction | indication is input, moves the display position of the said live image on the said monitor at least regarding the said cross direction based on the said instruction | indication.   The control means represents the OCT image in an orthogonal coordinate system having the probe axis as an origin, and displays the OCT image on the monitor. When the instruction is input, the OCT image on the monitor is The optical tomographic imaging apparatus according to claim 4 or 9, wherein the optical tomographic imaging apparatus is rotated based on the instruction.   The optical tomographic imaging apparatus according to claim 1, wherein the control unit moves the display position of the OCT image on the monitor by adjusting the timing of capturing the OCT data in each scan.   The optical tomography apparatus according to claim 1, wherein the control unit moves a display position of the OCT image on the monitor by image processing on the OCT image acquired by the acquisition unit.   The optical tomographic imaging apparatus according to claim 1, further comprising a touch panel monitor serving as both the operation unit and the monitor. The optical tomography apparatus according to claim 13, wherein the control unit moves a predetermined reference position in the OCT image to a position touched on the touch panel monitor.