OCT device and imaging control program

Abstract

To provide an OCT apparatus and an imaging control program which can more properly present to a user an image at a position that a user wants to confirm in detail in a range where a three-dimensional tomographic image is captured.SOLUTION: A control unit of an OCT apparatus executes the first imaging step, the extraction and display step, the additional imaging position setting step and the second imaging step. In the first imaging step, the control unit captures a three-dimensional tomographic image of a tissue by irradiating a two-dimensional measurement region expanding in the direction intersecting an optical axis of measurement light with the measurement light. In the extraction and display step, the control unit extracts a two-dimensional tomographic image from the three-dimensional tomographic image to display it on a display unit. In the additional imaging position setting step, the control unit sets the additional imaging position of the tomographic image in such a state that a two-dimensional tomographic image is displayed on a display unit. In the second imaging step, the control unit performs additional imaging of the tomographic image by irradiating the set additional imaging position with the measurement light.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to an OCT device that captures a tomographic image of a subject's tissue based on the principle of optical coherence tomography (OCT), and an imaging control program executed in the OCT device.

Background Art

[0002] Conventionally, a technique for capturing a tomographic image of a subject (for example, an eye to be examined, etc.) based on the principle of OCT is known. For example, in the OCT data processing device disclosed in Patent Document 1, the control unit sets any one of a plurality of types of line patterns for a two-dimensional measurement region in which a three-dimensional tomographic image of the eye to be examined is obtained. The control unit extracts a two-dimensional tomographic image on the line of the set line pattern from the three-dimensional tomographic image. In this case, the user can confirm the extraction results of the two-dimensional tomographic images corresponding to various line patterns based on the data of the three-dimensional tomographic image that has already been captured.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When arbitrarily extracting a two-dimensional tomographic image from a three-dimensional tomographic image, all the pixels of the two-dimensional tomographic image to be extracted do not always match the pixels constituting the three-dimensional tomographic image. That is, there may be a case where there are no pixels constituting the three-dimensional tomographic image at the position where the pixels constituting the two-dimensional tomographic image are extracted. In this case, it is also conceivable to perform a process such as interpolating the pixel values of the pixels constituting the two-dimensional tomographic image based on the pixel values of neighboring pixels. However, when performing processes such as interpolation, the pixel information often becomes inaccurate compared to the case where the measurement light is actually scanned at the same position to capture the two-dimensional tomographic image. In addition, the time required to capture the three-dimensional tomographic image is longer than the time required to capture the two-dimensional tomographic image. The longer the imaging time, the more likely the image quality is to deteriorate due to effects such as eye fatigue, thirst, and blinking. Even when reducing the number of two-dimensional tomographic images constituting the three-dimensional tomographic image in order to shorten the imaging time of the three-dimensional tomographic image, the image quality still deteriorates. As described above, in the method of extracting a two-dimensional tomographic image from a three-dimensional tomographic image, there may be a case where a two-dimensional tomographic image with good image quality cannot be extracted. Therefore, it is more useful if an image of a position that the user wants to check in detail can be presented to the user with high image quality within the range where the three-dimensional tomographic image has been captured.

[0005] A typical object of the present disclosure is to provide an OCT apparatus and an imaging control program capable of more appropriately presenting an image of a position that a user wants to check in detail within the range where a three-dimensional tomographic image has been captured to the user.

Means for Solving the Problems

[0006] The OCT apparatus provided by a typical embodiment in the present disclosure is an OCT apparatus that captures a tomographic image of the tissue of the eye to be examined by processing an OCT signal generated by reference light and measurement light irradiated to the eye to be examined. The control unit of the OCT apparatus irradiates the measurement light to a two-dimensional measurement region that spreads in a direction intersecting the optical axis of the measurement light to capture a three-dimensional tomographic image of the tissue, and a two-dimensional front image of the tissue when the three-dimensional tomographic image has been captured as viewed from a direction along the optical axis of the measurement light representsA front image display step for displaying on a display unit, an extraction position input step for inputting an instruction from a user for designating both an extraction position for extracting a two-dimensional tomographic image from the three-dimensional tomographic image and an additional imaging position of the tomographic image on the displayed two-dimensional front image, and both the extraction position and the additional imaging position are overlapped and displayed on the two-dimensional front image, and both the extraction position and the additional imaging position are linked and moved on the two-dimensional front image according to an instruction input by the user, thereby setting the extraction position and the additional imaging position; an extraction display step for extracting a two-dimensional tomographic image from the set extraction position of the three-dimensional tomographic image and displaying it on the display unit; a trigger input step for inputting a trigger for executing additional imaging in a state where the two-dimensional tomographic image is displayed on the display unit; and a second imaging step for performing additional imaging of the tomographic image by irradiating the set additional imaging position with the measurement light when a trigger for additional imaging is input.

[0007] The imaging control program provided by a typical embodiment in the present disclosure is an imaging control program executed by an OCT device that captures a tomographic image of the tissue of the eye to be examined by processing an OCT signal generated by a reference light and a measurement light irradiated on the eye to be examined. By executing the imaging control program by a control unit of the OCT device, a first imaging step of capturing a three-dimensional tomographic image of the tissue by irradiating the measurement light on a two-dimensional measurement region that spreads in a direction intersecting the optical axis of the measurement light, and a two-dimensional front image of the tissue when the three-dimensional tomographic image is captured as viewed from a direction along the optical axis of the measurement light representsA front image display step for causing the display unit to display, an extraction position for extracting a two-dimensional tomographic image from the three-dimensional tomographic image on the displayed two-dimensional front image, and a position input step for inputting an instruction from a user for designating both the extraction position and an additional imaging position of the tomographic image, and both the extraction position and the additional imaging position are overlapped and displayed on the two-dimensional front image, and both the extraction position and the additional imaging position are linked and moved on the two-dimensional front image according to an instruction input by the user, thereby setting the extraction position and the additional imaging position. A position display step, an extraction display step for extracting a two-dimensional tomographic image from the set extraction position among the three-dimensional tomographic images and displaying it on the display unit, a trigger input step for inputting a trigger for executing additional imaging in a state where the two-dimensional tomographic image is displayed on the display unit, and a second imaging step for performing additional imaging of the tomographic image by irradiating the set additional imaging position with the measurement light when a trigger for additional imaging is input, are executed by the OCT apparatus.

[0008] According to the OCT apparatus and the imaging control program according to the present disclosure, an image of a position that a user wants to confirm in detail among the range in which the three-dimensional tomographic image is captured is more appropriately presented to the user.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0010] <Summary> The OCT device exemplified in the present disclosure captures a tomographic image of the tissue of the eye to be examined by processing an OCT signal generated by reference light and measurement light irradiated on the eye to be examined. The OCT device includes an OCT light source, a branching optical element, an irradiation optical system, a multiplexing optical element, a light receiving element, and a control unit. The OCT light source emits light (OCT light). The branching optical element branches the light emitted from the OCT light source into measurement light and reference light. The irradiation optical system irradiates the tissue with the measurement light branched by the branching optical element. The multiplexing optical element multiplexes and interferes the measurement light reflected by the tissue and the reference light branched by the branching optical element. The light receiving element detects an interference signal by receiving the interference light generated by the multiplexing optical element.

[0011] The control unit executes a first imaging step, an extraction display step, an additional imaging position setting step, and a second imaging step. In the first imaging step, the control unit captures a three-dimensional tomographic image of the tissue by irradiating a two-dimensional measurement region that spreads in a direction intersecting the optical axis of the measurement light. In the extraction display step, the control unit extracts a two-dimensional tomographic image from the three-dimensional tomographic image and displays it on the display unit. In the additional imaging position setting step, the control unit sets an additional imaging position of the tomographic image while the two-dimensional tomographic image is being displayed on the display unit. In the second imaging step, the control unit performs additional imaging of the tomographic image by irradiating the set additional imaging position with the measurement light.

[0012] According to the OCT device exemplified in the present disclosure, a two-dimensional tomographic image is extracted from a three-dimensional tomographic image that has already been captured and is displayed on the display unit. In this state, an additional imaging position of the tomographic image is set, and additional imaging of the tomographic image is performed at the set position. Therefore, the user can grasp the additional imaging position after confirming the internal state of the tissue within the imaging range of the three-dimensional tomographic image by the extracted two-dimensional tomographic image. The image quality of the additionally captured tomographic image is less likely to deteriorate compared to the image quality of an image arbitrarily extracted from the three-dimensional tomographic image. Therefore, an image of a position that the user wants to check in detail within the range where the three-dimensional tomographic image has been captured is presented to the user more appropriately and with high image quality.

[0013] Note that in the extraction and display step, the control unit may extract a two-dimensional tomographic image having at least internal pixels of the three-dimensional tomographic image and display it on the display unit. In this case, the user can appropriately confirm the internal state of the tissue within the imaging range of the three-dimensional tomographic image by the extracted two-dimensional tomographic image.

[0014] The OCT device may include a scanning unit. The scanning unit scans the measurement light irradiated on the tissue by the irradiation optical system in a two-dimensional direction intersecting the optical axis. The three-dimensional tomographic image may be obtained by scanning the spot of the measurement light in a two-dimensional direction within the measurement region by the scanning unit. In this case, the three-dimensional tomographic image can be appropriately obtained by the OCT device.

[0015] However, it is also possible to change the configuration of the OCT device. For example, the irradiation optical system of the OCT device may simultaneously irradiate the measurement light on a two-dimensional region on the tissue of the subject. In this case, the light receiving element may be a two-dimensional light receiving element that detects the interference signal in the two-dimensional region on the tissue. That is, the OCT device may acquire OCT data according to the principle of so-called full-field OCT (FF-OCT). Further, the OCT device may simultaneously irradiate the measurement light on an irradiation line extending in a one-dimensional direction in the tissue and scan the measurement light in a direction intersecting the irradiation line. In this case, the light receiving element may be a one-dimensional light receiving element (for example, a line sensor) or a two-dimensional light receiving element. That is, the OCT device may acquire a tomographic image according to the principle of so-called line-field OCT (LF-OCT).

[0016] The control unit may further execute a line pattern setting step of setting any one of a plurality of types of line patterns in which at least any one of the arrangement, number, and shape of the lines is different from each other with respect to the two-dimensional measurement region where the three-dimensional tomographic image is obtained. The control unit may extract the two-dimensional tomographic image in the line of the set line pattern from the three-dimensional tomographic image and display it on the display unit. In this case, by setting a desirable line pattern, the state of the tissue within the imaging range of the three-dimensional tomographic image can be grasped more appropriately.

[0017] Note that a specific method for setting the line pattern can be appropriately selected. For example, the control unit may set any one of a plurality of types of line patterns according to an instruction input by the user. In this case, the two-dimensional tomographic image is extracted from the three-dimensional tomographic image in the pattern desired by the user. However, the pattern for extracting the two-dimensional tomographic image from the three-dimensional tomographic image may be predetermined.

[0018] The control unit may further execute an additional imaging condition setting step of setting imaging conditions for additional imaging of tomographic images (hereinafter, may also be referred to as "additional imaging conditions"). The control unit may perform additional imaging according to the set imaging conditions at the additional imaging position. In this case, high-quality tomographic images are additionally imaged under appropriate imaging conditions. Therefore, images of the positions that the user wants to check in detail are presented more appropriately.

[0019] The imaging conditions that can be set in the additional imaging condition setting step may include an imaging pattern for additional imaging of tomographic images (hereinafter, may also be referred to as "additional imaging pattern"). The additional imaging pattern is a pattern that defines at least any one of the arrangement, number, and shape of the tomographic images to be additionally imaged (for example, a pattern that defines at least any one of the arrangement, number, and shape of the lines for scanning the measurement light for additional imaging). By setting the additional imaging pattern, images of the positions that the user wants to check in detail are additionally imaged in a more appropriate pattern.

[0020] A specific method for setting the additional imaging pattern can also be appropriately selected. For example, the control unit may set any one of a plurality of types of additional imaging patterns according to an instruction input by the user. In this case, tomographic images are additionally imaged in the imaging pattern desired by the user. The additional imaging pattern may include a pattern for imaging one or more tomographic images. The additional imaging pattern may also include a pattern for imaging a three-dimensional tomographic image with a smaller imaging range and higher resolution than the three-dimensional tomographic image imaged in the first imaging step. In this case, since the three-dimensional tomographic image of the range that the user wants to check in detail is additionally imaged with high resolution, the state of the tissue can be confirmed more appropriately. However, it is also possible to predetermine the additional imaging pattern.

[0021] In the additional imaging condition setting step, imaging conditions other than the aforementioned imaging pattern may be set together with the additional imaging pattern or instead of the additional imaging pattern. For example, at least any one of the resolution of the two-dimensional tomographic image in the direction in which the measurement light is scanned (which may also be referred to as the "number of A-scan points"), the number of addition for performing addition averaging processing on a plurality of tomographic images taken at the same position, and the OCT sensitivity, etc. may be set as the additional imaging conditions. Also, at least any one of the optical path length of the OCT during additional imaging, the focus condition, the polarization condition, and the position of the internal fixation lamp, etc. may be set as the additional imaging conditions. Even in these cases, an image of the position that the user wants to check in detail is additionally imaged under the set appropriate conditions.

[0022] At least a part of the range of the tomographic image additionally imaged in the second imaging step may protrude outside the imaging range of the three-dimensional tomographic image taken in the first imaging step. Even in this case, the user can appropriately grasp the additional imaging position after checking the state of the tissue with the two-dimensional tomographic image extracted from the three-dimensional tomographic image. For example, when the position and range of the additional imaging are set by setting the center of the range of the tomographic image to be additionally imaged, the center of the range of the additional imaging may be set within the imaging range of the three-dimensional tomographic image taken in the first imaging step.

[0023] The control unit may further execute a front image display step and a position input step. In the front image display step, the control unit causes the display unit to display a two-dimensional front image of the tissue where the three-dimensional tomographic image was taken as viewed from the direction along the optical axis of the measurement light. In the position input step, the control unit receives an input of an instruction from the user for designating a position on the displayed two-dimensional front image. The control unit may set at least either an extraction position for extracting a two-dimensional tomographic image from the three-dimensional tomographic image and an additional imaging position according to the instruction specified by the user. In this case, the user can grasp the additional imaging position while confirming the position when viewing the tissue from the front on the two-dimensional front image and while confirming the internal state of the tissue with the tomographic image. Therefore, additional imaging is performed more appropriately.

[0024] The control unit may further execute a position display step of displaying each of the extraction position of the two-dimensional tomographic image and the additional imaging position on the two-dimensional front image. In this case, the user can confirm both the extraction position and the additional imaging position of the two-dimensional tomographic image on the two-dimensional front image of the tissue. Therefore, the internal state of the tissue and the additional imaging position are grasped more appropriately.

[0025] Note that the specific display method of the extraction position and the additional imaging position can be selected as appropriate. For example, when extracting a two-dimensional tomographic image from the three-dimensional tomographic image according to a set line pattern, the control unit may display the set line pattern on the two-dimensional front image as the extraction position. Further, the control unit may display the line along which the measurement light is scanned during additional imaging on the two-dimensional front image as the additional imaging position. The control unit may display the imaging region where the additional imaging is performed on the two-dimensional front image.

[0026] In the position input step, the control unit may input an instruction to specify both the extraction position and the additional imaging position together. In the position display step, the control unit may move both the extraction position and the additional imaging position in conjunction with each other on the two-dimensional frontal image in accordance with the instruction input by the user. In this case, since the extraction position and the additional imaging position are linked, the user can set the additional imaging position as is while checking the internal state of the tissue at the extraction position using the two-dimensional tomographic image. Therefore, the additional imaging is performed more appropriately.

[0027] The control unit may input a user's instruction to specify a position while displaying a two-dimensional front image, which is a still image, on the display unit. The control unit may acquire, in real time, a front observation image of the tissue viewed from a direction along the optical axis of the measurement light. The control unit may identify, based on the two-dimensional front image and the front observation image, an additional imaging position specified on the two-dimensional front image on a front observation image captured in real time, and perform additional imaging at the identified additional imaging position. In this case, the user can specify a position on a still image, which makes it easier and more accurate to specify a position than specifying a position on a video. Furthermore, the additional imaging is performed after the additional imaging position specified on the still image is identified on a front observation image captured in real time. Therefore, even if the tissue is moving, the additional imaging is accurately performed at the additional imaging position specified on the still image.

[0028] The method of identifying and automatically tracking the additional shooting position specified on the still image on the front observation image captured in real time can be selected as appropriate. For example, the control unit may identify the additional shooting position on the front observation image by aligning the two-dimensional front image with the front observation image using known image processing or the like. Alternatively, the control unit may repeatedly capture additional images while tracing (automatically tracking) the same position on the two-dimensional front observation image using the front observation image captured in real time.

[0029] The control unit may input an instruction from the user for specifying a position while displaying, on the display unit as a two-dimensional front image, an Enface image when viewed from a direction along the optical axis of the measurement light of the three-dimensional tomographic image. In this case, the extraction position of the two-dimensional tomographic image on the Enface image (which can be displayed as a line) and the position where the two-dimensional tomographic image is actually extracted from the three-dimensional tomographic image completely coincide. Therefore, the user can grasp the additional imaging position after more accurately confirming the internal state of the tissue.

[0030] The control unit may generate an analysis map that two-dimensionally shows the distribution of the analysis results of the three-dimensional tomographic image. The control unit may input an instruction from the user for specifying a position while displaying the analysis map on the display unit as a two-dimensional front image. In this case, the user can specify at least one of the extraction position and the additional imaging position in consideration of the distribution of the analysis results. Thus, additional imaging is performed more appropriately. Also, similar to the case where a position is specified on the Enface image, there is no deviation in the extraction position of the two-dimensional tomographic image.

[0031] Note that the specific form of the analysis map can be appropriately selected. For example, the analysis map may be a thickness map that two-dimensionally shows the distribution of the thickness of a specific layer in the tissue. In this case, the user can specify a position after appropriately grasping the thickness of the specific layer.

[0032] The control unit may further execute an image input step and a confidence information acquisition step. In the image input step, the control unit is trained by a machine learning algorithm and inputs the three-dimensional tomographic image captured in the first imaging step into a mathematical model that executes an analysis of at least one of a specific structure and a disease of the eye to be examined shown in the input ophthalmic image. In the confidence information acquisition step, the control unit acquires confidence information indicating the confidence level of the analysis executed by the mathematical model for the three-dimensional tomographic image. The control unit may display, on the display unit, a two-dimensional front image including the confidence information.

[0033] In a mathematical model trained with a plurality of ophthalmic images, when an ophthalmic image approximating the ophthalmic images used for training is input, the confidence level of the analysis of the ophthalmic image tends to increase. On the other hand, when an ophthalmic image not approximating the ophthalmic images used for training is input to the mathematical model, the confidence level of the analysis of the ophthalmic image tends to decrease. Therefore, when a three-dimensional tomographic image of a tissue in which some abnormality (such as a disease, etc.) exists is input to the mathematical model, the confidence level of the site where the abnormality exists is likely to decrease. Thus, by referring to the two-dimensional tomographic image including the confidence information, the user can easily check the state of the site where there is a high possibility of the existence of an abnormality.

[0034] A specific method for displaying a two-dimensional frontal image including confidence information can also be appropriately selected. For example, the control unit may display a confidence map showing the distribution of the confidence information two-dimensionally as a two-dimensional frontal image or superimposed on the two-dimensional frontal image. Further, the control unit may add the value of the confidence level or the like on the two-dimensional frontal image.

[0035] The control unit may set at least one of the extraction position and the additional imaging position of the two-dimensional tomographic image based on the analysis result of the three-dimensional tomographic image. In this case, based on the analysis result, the position is automatically determined. Thus, the additional imaging position can be grasped more appropriately.

[0036] In addition, a specific method for setting the position based on the analysis result of the three-dimensional tomographic image can also be appropriately selected. For example, the control unit may perform image processing, which is a kind of analysis processing, on the three-dimensional tomographic image to identify a feature site (for example, at least any one of the optic nerve head, macula, blood vessels, and lesion sites, etc.) existing in the imaging region. The control unit may set the position of the identified feature site as at least any one of the extraction position and the additional imaging position. Further, the control unit may automatically set at least any one of the extraction position and the additional imaging position based on the analysis result of the thickness of a specific layer in the tissue. Also, as described above, the control unit may execute an image input step and a confidence information acquisition step for acquiring confidence information, and automatically set at least any one of the extraction position and the additional imaging position based on the acquired confidence. For example, a position with the lowest confidence, or a position where the confidence is below a threshold value, etc. may be set as at least any one of the extraction position and the additional imaging position.

[0037] The control unit may link and store the data of the three-dimensional tomographic image taken in the first imaging step and the data of the additional imaging image taken in the second imaging step for the tissue of the same subject eye in the storage device. The control unit may display the two-dimensional tomographic image extracted from the three-dimensional tomographic image and the additional imaging image linked and stored in the same three-dimensional tomographic image simultaneously or by switching, together with the data related to the three-dimensional tomographic image (for example, at least any one of the three-dimensional tomographic image and the analysis result of the three-dimensional tomographic image, etc.) on the display unit. In this case, with the data related to the three-dimensional tomographic image being displayed, the two-dimensional tomographic image extracted from the three-dimensional tomographic image and the additional imaging image of the same tissue are displayed in a state where they can be easily compared. Therefore, the convenience for the user is further improved.

[0038] A specific method for displaying the extracted two-dimensional tomographic image and the additional captured image can be appropriately selected. For example, when the control unit causes the display unit to display data related to the three-dimensional tomographic image, it may display a GUI (Graphical User Interface: for example, an icon, etc.) for the user to input an instruction to switch the display between the extracted two-dimensional tomographic image and the additional captured image. The control unit may switch the display between the two-dimensional tomographic image and the additional captured image every time the GUI is operated.

[0039] <Embodiment> Hereinafter, one of the typical embodiments according to the present disclosure will be described. As an example, the OCT apparatus 1 of the present embodiment can acquire and process OCT data (for example, a three-dimensional tomographic image 2 (see FIG. 2) and a two-dimensional tomographic image, etc.) of the fundus of the eye to be examined E as the subject. However, even when processing OCT data of tissues other than the fundus in the eye to be examined E (for example, the anterior segment of the eye to be examined E, etc.), or a subject other than the eye to be examined E (for example, skin, digestive organs, brain, blood vessels (including cardiovascular), or teeth, etc.), at least a part of the technology exemplified in the present disclosure can be applied. OCT data is data acquired based on the principle of optical coherence tomography (OCT).

[0040] Referring to FIG. 1, the schematic configuration of the OCT apparatus 1 of the present embodiment will be described. The OCT apparatus 1 includes an OCT unit 10 and a control unit 30. The OCT unit 10 includes an OCT light source 11, a coupler (optical splitter) 12, a measurement optical system 13, a reference optical system 20, a light receiving element 22, and a front observation optical system 23.

[0041] The OCT light source 11 emits light (OCT light) for acquiring OCT data. The coupler 12 splits the OCT light emitted from the OCT light source 11 into measurement light and reference light. Further, the coupler 12 in the present embodiment combines and interferes the measurement light reflected by the subject (the fundus of the eye E in the present embodiment) and the reference light generated by the reference optical system 20. That is, the coupler 12 in the present embodiment serves as a branching optical element that branches the OCT light into measurement light and reference light and a multiplexing optical element that multiplexes the reflected light of the measurement light and the reference light. Note that it is also possible to change at least one of the configurations of the branching optical element and the multiplexing optical element. For example, elements other than the coupler (for example, a circulator, a beam splitter, etc.) may be used.

[0042] The measurement optical system 13 guides the measurement light split by the coupler 12 to the subject and returns the measurement light reflected by the subject to the coupler 12. The measurement optical system 13 includes a scanning unit 14, an irradiation optical system 16, and a focus adjustment unit 17. The scanning unit 14 can scan (deflect) the measurement light in a two-dimensional direction intersecting the optical axis of the measurement light by being driven by the drive unit 15. In the present embodiment, two galvanometer mirrors capable of deflecting the measurement light in different directions are used as the scanning unit 14. However, another device that deflects light (for example, at least any one of a polygon mirror, a resonant scanner, an acousto-optic element, etc.) may be used as the scanning unit 14. The irradiation optical system 16 is provided on the downstream side of the optical path (that is, the subject side) with respect to the scanning unit 14 and irradiates the tissue of the subject with the measurement light. The focus adjustment unit 17 adjusts the focus of the measurement light by moving an optical member (for example, a lens) included in the irradiation optical system 16 in a direction along the optical axis of the measurement light.

[0043] The reference optical system 20 generates reference light and returns it to the coupler 12. The reference optical system 20 of the present embodiment generates reference light by reflecting the reference light split by the coupler 12 with a reflection optical system (for example, a reference mirror). However, the configuration of the reference optical system 20 can also be changed. For example, the reference optical system 20 may transmit the light incident from the coupler 12 without reflecting it and return it to the coupler 12. The reference optical system 20 includes an optical path length adjustment unit 21 that changes the optical path length difference between the measurement light and the reference light. In the present embodiment, the optical path length difference is changed by moving the reference mirror in the optical axis direction. Note that the configuration for changing the optical path length difference may be provided in the optical path of the measurement optical system 13.

[0044] The light receiving element 22 detects an interference signal by receiving the interference light of the measurement light and the reference light generated by the coupler 12. In the present embodiment, the principle of Fourier domain OCT is adopted. In Fourier domain OCT, the spectral intensity of the interference light (spectral interference signal) is detected by the light receiving element 22, and a complex OCT signal is obtained by performing a Fourier transform on the spectral intensity data. As an example of Fourier domain OCT, Spectral-domain-OCT (SD-OCT), Swept-source-OCT (SS-OCT), etc. can be adopted. Also, for example, Time-domain-OCT (TD-OCT) etc. can be adopted.

[0045] In the present embodiment, SD-OCT is adopted. In the case of SD-OCT, for example, a low coherence light source (broadband light source) is used as the OCT light source 11, and a spectroscopic optical system (spectrometer) that splits the interference light into each frequency component (each wavelength component) is provided near the light receiving element 22 in the optical path of the interference light. In the case of SS-OCT, for example, a wavelength scanning light source (wavelength variable light source) that changes the emission wavelength at high speed in time is used as the OCT light source 11. In this case, the OCT light source 11 may include a light source, a fiber ring resonator, and a wavelength selection filter. Examples of the wavelength selection filter include a filter that combines a diffraction grating and a polygon mirror, and a filter that uses a Fabry-Perot etalon.

[0046] In addition, in the present embodiment, the spot of the measurement light is scanned within the two-dimensional measurement region by the scanning unit 14, thereby acquiring three-dimensional OCT data (three-dimensional tomographic image 2). However, it is also possible to change the principle of acquiring the three-dimensional OCT data. For example, the three-dimensional OCT data may be acquired according to the principle of line-field OCT (hereinafter referred to as "LF-OCT"). In LF-OCT, the measurement light is simultaneously irradiated onto an irradiation line extending in a one-dimensional direction in the tissue, and the interference light between the reflected light of the measurement light and the reference light is received by a one-dimensional light-receiving element (for example, a line sensor) or a two-dimensional light-receiving element. In the two-dimensional measurement region, the measurement light is scanned in a direction intersecting the irradiation line, thereby acquiring three-dimensional OCT data. Further, the three-dimensional OCT data may be acquired according to the principle of full-field OCT (hereinafter referred to as "FF-OCT"). In FF-OCT, the measurement light is irradiated onto the two-dimensional measurement region on the tissue, and the interference light between the reflected light of the measurement light and the reference light is received by a two-dimensional light-receiving element. In this case, the OCT apparatus 1 may not include the scanning unit 14.

[0047] The front observation optical system 23 is provided for photographing a front observation image of the tissue of the subject (the fundus of the examined eye E in the present embodiment) in real time. The front observation image in the present embodiment is a two-dimensional image when the tissue is viewed from the direction (front direction) along the optical axis of the measurement light of OCT. In the present embodiment, a scanning laser ophthalmoscope (SLO) is adopted as the front observation optical system 23. However, as the configuration of the front observation optical system 23, a configuration other than SLO (for example, an infrared camera that irradiates infrared light uniformly onto the two-dimensional photographing range to photograph a front image, etc.) may be adopted.

[0048] Also, as shown in FIG. 2, the OCT apparatus 1 can acquire (generate) an Enface image 3, which is a two-dimensional frontal image when the tissue is viewed from the direction (front direction) along the optical axis of the measurement light, based on the captured three-dimensional tomographic image 2. When the Enface image 3 is acquired in real time, the acquired Enface image 3 can also be used as the aforementioned frontal observation image. In this case, it is also possible to omit the frontal observation optical system 23. The data of the Enface image 3 may be, for example, integrated image data in which luminance values are integrated in the depth direction (Z direction) at each position in the XY direction, integrated values of spectral data at each position in the XY direction, luminance data at each position in the XY direction in a certain depth direction, luminance data at each position in the XY direction in any layer of the retina (for example, the retinal surface layer), and the like. Further, the Enface image 3 may be obtained from a motion contrast image (for example, an OCT angiography image) obtained by acquiring a plurality of OCT signals at different times from the same position of the tissue of the patient's eye.

[0049] The control unit 30 controls various operations of the OCT apparatus 1. The control unit 30 includes a CPU 31, a RAM 32, a ROM 33, and a non-volatile memory (NVM) 34. The CPU 31 is a controller that performs various controls. The RAM 32 temporarily stores various information. The ROM 33 stores programs executed by the CPU 31 and various initial values and the like. The NVM 34 is a non-transitory storage medium that can retain the stored content even when the power supply is cut off. The imaging control program for executing the imaging control process (see FIG. 3) described later may be stored in the NVM 34.

[0050] The control unit 30 is connected to a microphone 36, a monitor 37, and an operation unit 38. The microphone 36 inputs sound. The monitor 37 is an example of a display unit that displays various images. The operation unit 38 is operated by the user to input various operation instructions to the OCT apparatus 1. For the operation unit 38, various devices such as a mouse, a keyboard, a touch panel, and a foot switch can be used, for example. Note that various operation instructions may be input to the OCT apparatus 1 when sound is input to the microphone 36. In this case, the CPU 31 may determine the type of operation instruction by performing voice recognition processing on the input sound.

[0051] In the present embodiment, an integrated OCT apparatus 1 in which the OCT unit 10 and the control unit 30 are incorporated in one housing is exemplified. However, it goes without saying that the OCT apparatus 1 may include a plurality of devices with different housings. For example, the OCT apparatus 1 may include an optical device incorporating the OCT unit 10 and a PC connected to the optical device by wire or wirelessly. In this case, the control unit provided in the optical device and the control unit of the PC may both function as the control unit 30 of the OCT apparatus 1. Further, a device disposed at the site where imaging of the eye to be examined is performed and a device disposed at the site of the user (for example, a doctor or the like) may be connected via a network. In this case, even when the user is at a site different from the imaging site, the user can instruct additional imaging at an appropriate position by the processing described below.

[0052] (Imaging control processing) With reference to FIGS. 3 to 10, the imaging control processing executed by the OCT apparatus 1 will be described. In the imaging control processing of the present embodiment, first, a three-dimensional tomographic image 2 of the tissue of the eye to be examined is taken. Next, using the taken three-dimensional tomographic image 2, various processes for appropriately performing additional imaging of the tomographic image are executed. The CPU 31 of the OCT apparatus 1 executes the imaging control processing shown in FIG. 3 according to the imaging control program stored in the NVM 34. First, the CPU 31 executes a first imaging process (S1). In the first imaging process, the three-dimensional tomographic image 2 is taken.

[0053] Referring to FIG. 4, the first imaging process will be described in detail. The CPU 31 starts imaging a front view image of the tissue to be imaged (the fundus of the eye E to be examined in this embodiment), and displays the captured image on the monitor 37 (S21). FIG. 5 shows an example of the front view image 50 displayed on the monitor 37. In the example shown in FIG. 5, the optic disc (hereinafter sometimes referred to as the "disc") 51, the macula 52, and the fundus blood vessels 53 of the eye E to be examined are captured in the front view image 50. Note that the front view image 50 is repeatedly and intermittently captured (i.e., captured in real time) and displayed as a moving image on the monitor 37. As described above, the front view image 50 in this embodiment is an image (SLO image in this embodiment) captured by the front view optical system 23 (see FIG. 1). However, as described above, the Enface image 3, the infrared image, or the like may be used as the front view image 50.

[0054] Next, the CPU 31 displays the measurement region 55 on the front view image 50 (S22). The measurement region 55 is a region of the tissue to be imaged for the three-dimensional tomographic image 2. The measurement region 55 is a two-dimensional region that extends in a direction intersecting the optical axis of the measurement light. When the imaging operation of the three-dimensional tomographic image 2 is started, the measurement light is irradiated into the measurement region 55.

[0055] In the example shown in FIG. 5, the frame portion of the measurement region 55 is electronically displayed on the front view image 50. However, the display method of the measurement region 55 can be changed as appropriate. For example, light indicating the frame portion of the measurement region 55 may be directly irradiated onto the tissue. In this case, the user can grasp the measurement region 55 by checking the position of the light captured in the front view image 50. Also, in the example shown in FIG. 5, the measurement region 55 is rectangular. However, it goes without saying that the shape of the measurement region 55 may be a shape other than rectangular (for example, circular).

[0056] While the user checks the front observation image 50, the user performs the alignment of the OCT apparatus 1 with respect to the subject and adjusts so that the measurement region 55 is in an appropriate position with respect to the tissue. In the present embodiment, in order to include both the papilla 51 and the macula 52 in the measurement region 55, the center of the measurement region 55 is adjusted to be located between the papilla 51 and the macula 52. Note that the alignment of the OCT apparatus 1 with respect to the subject may be automatically performed.

[0057] Next, the CPU 31 determines whether an instruction to execute Optimize has been input (S24). Optimize is a function that adjusts the optical path length difference by the optical path length difference adjustment unit 21 (see FIG. 1) and optimizes the focus by the focus adjustment unit 17. When an instruction to execute Optimize is input (S24: YES), the CPU 31 executes the Optimize operation (S25), and the process proceeds to S7. If an instruction to execute Optimize has not been input (S24: NO), the process directly proceeds to S27.

[0058] Next, the CPU 31 determines whether a trigger signal for starting the acquisition of the three-dimensional tomographic image 2 has been generated (input in the present embodiment) (S27). As an example, in the present embodiment, in a state where the alignment and the Optimize operation are completed, when the user operates a Release button (not shown) for instructing the start of acquisition, the trigger signal is generated and input to the CPU 31. However, the method of generating the trigger signal may be changed. For example, the trigger signal may be generated by inputting a specific voice to the microphone 36. Further, the CPU 31 may automatically generate the trigger signal when the acquisition preparation (for example, the alignment and the Optimize operation) is completed. If the trigger signal has not been generated (S27: NO), the process returns to S24.

[0059] When a trigger signal is generated (S27: YES), the CPU 31 executes a process for capturing the three-dimensional tomographic image 2 of the measurement region 55 of the tissue (S28). The CPU 31 of the present embodiment controls the scanning unit 14 and scans the spot of the measurement light within the two-dimensional measurement region 55 to capture the three-dimensional tomographic image 2 of the measurement region 55. As an example, in the present embodiment, as shown in FIG. 5, a plurality of linear scanning lines (scan lines) 58 for scanning the spot are set at equal intervals within the measurement region 55, and the spot of the measurement light is scanned on each of the scanning lines 58 to capture the three-dimensional tomographic image 2 of the measurement region 55.

[0060] Note that the OCT apparatus 1 of the present embodiment can capture a tomographic image while tracking the scanning position of the spot of the measurement light using a two-dimensional front image (template image) of the reference tissue and a front observation image captured in real time by the front observation optical system 23. By performing tracking during imaging, a tomographic image at an accurate position can be captured even when the eye moves. The user can also set in advance whether to execute tracking during imaging.

[0061] Also, the OCT apparatus 1 of the present embodiment can capture a plurality of tomographic images at the same position by scanning the measurement light a plurality of times on the same scanning line 58. The OCT apparatus 1 can execute an addition average process on the plurality of tomographic images captured at the same position. By performing the addition average process, the image quality of the tomographic image is improved. The user can also set in advance whether to execute the addition average process.

[0062] Returning to the description of FIG. 3. When the first imaging process (S1) ends, various processes for optimizing the additional imaging of the tomographic image are executed. First, the CPU 31 executes a confirmation screen display process for displaying the imaging result confirmation screen 60 (see FIG. 6) on the monitor 37 (S2).

[0063] Referring to FIG. 6, the captured image confirmation screen 60 in the present embodiment will be described. The captured image confirmation screen 60 is displayed to allow the user to confirm the image captured in the first capturing process (see FIG. 4). Further, the captured image confirmation screen 60 of the present embodiment is displayed to optimize the additional capture of tomographic images. As shown in FIG. 6, a two-dimensional front image 70, two-dimensional tomographic images 5 (5A, 5B), and an additional capture pattern selection section 80 are displayed on the captured image confirmation screen 60 of the present embodiment.

[0064] The two-dimensional front image 70 is a two-dimensional image when viewing the tissue where the three-dimensional tomographic image 2 was captured from the direction along the optical axis of the measurement light of OCT (that is, the front). The OCT apparatus 1 of the present embodiment allows the user to confirm on the two-dimensional front image 70 the extraction position of the two-dimensional tomographic image 5 extracted and displayed from the three-dimensional tomographic image 2, the additional capture position of the tomographic image, and the like.

[0065] As an example, the OCT apparatus 1 of the present embodiment allows the user to confirm the extraction position of the two-dimensional tomographic image 5 by displaying line patterns 75 (75A, 75B) on the two-dimensional front image 70. In other words, the OCT apparatus 1 sets a line pattern for the two-dimensional measurement region 55 (overlapping with the two-dimensional front image 70) where the three-dimensional tomographic image 2 was captured, and displays the two-dimensional tomographic image 5 (for example, the two-dimensional tomographic image 5 in the cross section intersecting the line, etc.) on the line of the set line pattern on the captured image confirmation screen 60. In the example shown in FIG. 6, a line pattern in which a vertically extending line 75A and a horizontally extending line 75B cross each other is set. The OCT apparatus 1 extracts the two-dimensional tomographic image 5A on the line 75A and the two-dimensional tomographic image 5B on the line 75B from the three-dimensional tomographic image 2 and displays them on the monitor 37.

[0066] In addition, the OCT device 1 of the present embodiment allows the user to confirm the additional imaging position of the tomographic image (specifically, the candidate position for additional imaging in the state shown in FIG. 6) by displaying the additional imaging pattern 78 on the two-dimensional front image 70. In other words, the OCT device 1 sets and displays the selected additional imaging pattern 78 at the additional imaging position on the two-dimensional front image 70 according to an instruction from the user or the like. When an instruction to execute additional imaging is input, the OCT device 1 executes additional imaging of the tomographic image by scanning the measurement light on the line of the additional imaging pattern 78 set at the time of input of the instruction.

[0067] Details will be described later, but the OCT device 1 of the present embodiment receives an instruction from the user for specifying a position (in the present embodiment, the extraction position of the two-dimensional tomographic image 5 and the additional imaging position) on the two-dimensional front image 70 which is a still image. In this case, since the user can specify the position on the still image, the position can be specified more easily and accurately than when specifying the position on a moving image. However, the OCT device 1 can also receive an instruction from the user for specifying a position on the moving image.

[0068] The additional imaging pattern selection unit 80 is displayed to allow the user to select at least one of a plurality of types of additional imaging patterns. As an example, in the additional imaging pattern selection unit 80 shown in FIG. 6, the additional imaging patterns of cross, multi (cross), radial (6), radial (12), and circle are displayed as candidates in order from the top. In the example shown in FIG. 6, as a result of the user selecting radial (6), radial (6) in the additional imaging pattern selection unit 80 is highlighted, and the additional imaging pattern 78 of radial (6) is displayed at the additional imaging position on the two-dimensional front image 70. Note that the additional imaging pattern may include a pattern for capturing a three-dimensional tomographic image having a smaller imaging range and higher resolution than the three-dimensional tomographic image 2 captured in the first imaging process (see FIG. 4).

[0069] The OCT device 1 of this embodiment overlaps the area for setting the extraction position (position of the line pattern 75) of the two-dimensional tomographic image 5 and the area for setting the additional imaging position (position of the additional imaging pattern 78). Specifically, the OCT device 1 of this embodiment sets the extraction position and the additional imaging position with the center of the extraction position (position of the line pattern 75) of the two-dimensional tomographic image 5 and the center of the additional imaging position (position of the additional imaging pattern 78) being coincident. Therefore, the user can start additional imaging after appropriately grasping the internal state of the tissue at the additional imaging position based on the extracted and displayed two-dimensional tomographic image 5. However, the extraction position of the two-dimensional tomographic image 5 and the additional imaging position of the tomographic image may be set separately.

[0070] Referring to FIG. 7, the confirmation screen display process (S2, see FIG. 3) will be described in detail. First, the CPU 31 executes a process for displaying the two-dimensional front image 70 on the imaging result confirmation screen 60 (S31 to S42). As an example, in this embodiment, any one of the front observation image captured by the front observation optical system 23, the Enface image 3 (see FIG. 2), the analysis map 73, and the confidence display image 74 can be displayed on the monitor 37 as the two-dimensional front image 70. The user can preset the type of image to be displayed as the two-dimensional front image 70 among multiple types of images on a setting screen or the like.

[0071] When the setting for displaying the front observation image is made as the two-dimensional front image 70 (S31: YES), the CPU 31 acquires the still front observation image captured by the front observation optical system 23 and displays it on the monitor 37 (S32). Then, the process proceeds to S40. The front observation image displayed in S32 is preferably the image captured by the front observation optical system 23 when the three-dimensional tomographic image 2 is captured.

[0072] When the setting to display the Enface image 3 is made as the two-dimensional front image 70 (S34: YES), the CPU 31 acquires the still Enface image 3 (see FIG. 2) of the still image and causes it to be displayed on the monitor 37 (S35). Thereafter, the process proceeds to S40. The Enface image 3 displayed in S35 is acquired (generated) based on the three-dimensional tomographic image 2 taken in the first imaging step (see FIG. 4). Therefore, the extraction position of the two-dimensional tomographic image on the Enface image 3 (for example, the position of the line pattern 75 shown in FIG. 6) and the position where the two-dimensional tomographic image 5 is actually extracted from the three-dimensional tomographic image 2 completely match. Thus, the internal state of the tissue can be confirmed more accurately.

[0073] When the setting to display the analysis map 73 is made as the two-dimensional front image 70 (S37: YES), the CPU 31 analyzes the three-dimensional tomographic image 2 taken in the first imaging step (see FIG. 4) and generates an analysis map 73 that two-dimensionally shows the distribution of the analysis results. The CPU 31 causes the generated analysis map 73 to be displayed on the monitor 37 (S38). Thereafter, the process proceeds to S40. The analysis map 73 of the present embodiment is a still image. In the example shown in FIG. 8, the analysis map 73 is superimposed and displayed on the two-dimensional area where the analysis has been performed among the image areas of the front observation image 72 taken by the front observation optical system 23. Therefore, the user can grasp the analysis results by the analysis map 73 while confirming the position of the tissue and the like by the front observation image 72. However, it is also possible to change the display method of the analysis map 73. For example, the analysis map 73 may be displayed alone as the two-dimensional front image 70.

[0074] Note that the analysis map 73 exemplified in the present embodiment is a thickness map that two-dimensionally shows the distribution of the thickness of a specific layer in the tissue (for example, the layer between the ILM and the RPE / BM, etc.) by the change in color. However, an analysis map different from the thickness map (for example, a map showing the distribution of the analysis results regarding the blood flow in the fundus of the eye, etc.) may be used. Also, a map showing the distribution of the difference between the data of the analysis results for a normal eye (normal eye data) and the analysis results of the eye to be examined (so-called "deviation map") may be used.

[0075] Next, the CPU 31 determines whether a setting is made to include confidence information in the two-dimensional front image 70 (S40). The confidence information is information on the confidence of the analysis performed by the mathematical model trained by the machine learning algorithm. The "confidence" may be the degree of certainty of the analysis of the ophthalmic image by the mathematical model, or may be the reciprocal of the low degree of certainty (which can also be expressed as uncertainty). Also, for example, when the uncertainty is expressed as x%, the confidence may be a value expressed as (100 - x)%. That is, not only when using the value of "confidence" itself indicating a high degree of certainty of the analysis, but also when using a low degree of certainty (uncertainty) of the analysis, the result is the same. In a mathematical model trained with a plurality of ophthalmic images, when an ophthalmic image approximating the ophthalmic images used for training is input, the confidence of the analysis of the ophthalmic image tends to increase. On the other hand, when an ophthalmic image not approximating the ophthalmic images used for training is input to the mathematical model, the confidence of the analysis of the ophthalmic image tends to decrease. Therefore, when a three-dimensional tomographic image of a tissue in which some abnormality (such as a disease, etc.) exists is input to the mathematical model, the confidence of the site where the abnormality exists is likely to be low.

[0076] When a setting is made to use the two-dimensional front image including the confidence information (S40: YES), the CPU 31 inputs the three-dimensional tomographic image 2 taken in the first imaging step (see FIG. 4) to the mathematical model trained by the machine learning algorithm (S41). The mathematical model is trained to output an analysis result for at least either a specific structure of the eye to be examined and a disease shown in the input ophthalmic image. The confidence information is obtained along with the analysis result. The CPU 31 acquires the confidence information regarding the analysis performed by the mathematical model and adds it onto the two-dimensional front image 70 (S42).

[0077] A specific method for adding confidence information to the two-dimensional front image 70 can be appropriately selected. For example, in the confidence display image 74 shown in FIG. 9, confidence information is added on the image of another two-dimensional front image 70 (for example, the front observation image 72 taken by the front observation optical system 23). Specifically, among the regions of the two-dimensional front image 70, a display indicating the degree of low confidence is added to the regions where the obtained confidence is less than the threshold value. Therefore, the user can appropriately grasp the regions where there is a high possibility of some abnormality in the tissue. Also, the confidence map itself showing the two-dimensional distribution of confidence may be used as the two-dimensional front image 70.

[0078] Next, the CPU 31 executes a process of automatically setting the extraction position and the additional imaging position of the two-dimensional tomographic image 5 (S44). For example, if the automatically set additional imaging position is appropriate, the user may simply input an execution instruction for the additional imaging. Therefore, the working efficiency of the user is improved.

[0079] As an example, in the present embodiment, the CPU 31 automatically sets the extraction position and the additional imaging position based on the analysis result for the three-dimensional tomographic image 2. For example, the CPU 31 may identify a feature site (for example, at least any one of the optic nerve head, macula, blood vessels, and lesion sites, etc.) existing in the imaging region by performing image processing, which is a kind of analysis process, on the three-dimensional tomographic image 2. The CPU 31 may set the position of the identified feature site as the extraction position and the additional imaging position. Also, the CPU 31 may automatically set the extraction position and the additional imaging position based on the analysis result of the thickness of a specific layer in the tissue. Further, the CPU 31 may automatically set the extraction position and the additional imaging position based on the confidence information described above. For example, the position with the lowest confidence, or the position where the confidence is below the threshold value, etc. may be set as the extraction position and the additional imaging position. Note that the CPU 31 may set a predetermined default position (for example, the center of the two-dimensional front image 70, etc.) as at least one of the extraction position and the additional imaging position without using the analysis result of the three-dimensional tomographic image 2.

[0080] Next, the CPU 31 displays the extraction position and the additional imaging position of the two-dimensional tomographic image 5 on the two-dimensional front image 70 (S45). As described above, in the present embodiment, among the plurality of types of line patterns, the set line pattern 75 is displayed at the extraction position. Also, among the plurality of types of additional imaging patterns, the set additional imaging pattern 78 is displayed at the additional imaging position. In S45, the pattern display process may be performed based on the line pattern 75 and the additional imaging pattern 78 defined by default, or the pattern set in the previous imaging control process. In the present embodiment, the extraction position and the additional imaging position overlap. Therefore, in the example shown in FIG. 6, the line pattern 75 and the additional imaging pattern 78 are displayed in an overlapping state.

[0081] Next, the CPU 31 extracts the two-dimensional tomographic image 5 from the set extraction position among the three-dimensional tomographic images 2 taken in the first imaging step (see FIG. 4) and displays it on the monitor 37 (S46). Specifically, in the present embodiment, the two-dimensional tomographic image 5 in the line of the set line pattern 75 is extracted from the three-dimensional tomographic image 2 and displayed on the monitor 37.

[0082] Returning to the description of FIG. 3, when the confirmation screen display process (S2) ends, the CPU 31 determines whether an instruction to set a line pattern for extracting the two-dimensional tomographic image 5 has been input (S4). In the present embodiment, the user can input an instruction to set a line pattern by operating the operation unit 38. As an example, in the present embodiment, when a predetermined operation is performed on the operation unit 38, the line pattern setting screen shown in FIG. 10 pops up and is displayed on the monitor 37. The user can input an instruction to set a line pattern to the OCT apparatus 1 by selecting a desired line pattern from among the plurality of types of line patterns displayed on the line pattern setting screen 90. In the example shown in FIG. 10, since a cross line pattern is set, the cross line pattern 75 is displayed on the imaging result confirmation screen 60 shown in FIG. 6.

[0083] When an instruction to set a line pattern is input (S4: YES), the CPU 31 sets the line pattern 75 selected by the user from among a plurality of types of line patterns and causes it to be displayed on the monitor 37 (S5). The CPU 31 extracts the two-dimensional tomographic image 5 in the line of the set line pattern 75 and causes it to be displayed on the monitor 37. Thereafter, the process proceeds to S8.

[0084] Next, the CPU 31 determines whether an instruction to set additional imaging conditions has been input (S8). In the present embodiment, among the additional imaging conditions that can be set in S8, an additional imaging pattern, which is a pattern of additional imaging of tomographic images, is included. As described above, the user can input an instruction to set an additional imaging pattern by selecting a desired additional imaging pattern from among a plurality of types of additional imaging patterns displayed on the additional imaging pattern selection unit 80.

[0085] Also, in S8 of the present embodiment, together with the additional imaging pattern, at least any one of the resolution of the two-dimensional tomographic image in the direction in which the measurement light is scanned (sometimes referred to as the "number of A-scan points"), the number of images to be added when performing the addition average process, the OCT sensitivity, the optical path length of the OCT, the focus condition (for example, the focus position in the depth direction), the polarization condition, and the position of the internal fixation lamp, etc. is set as the additional imaging condition. For example, in S8, the user can also select the Retinal mode and the Choridal mode as the conditions for the optical path length of the OCT. The Retinal mode is a mode in which the zero-delay position of the optical path length (the corresponding longitudinal position on the subject when the optical path length of the reference light and the optical path length of the measurement light coincide) is set at a position shallower than the surface of the retina. The Choridal mode is a mode in which the zero-delay position of the optical path length is set at a position deeper than the choroid. By selecting the Retinal mode or the Choridal mode according to the position to be confirmed in detail among the positions in the depth direction, the user can more appropriately confirm the state of the tissue. Also, in the OCT apparatus 1, as the passing position of the measurement light approaches the periphery from the center of the objective lens, the optical path becomes longer, the measurement light is more likely to be scattered, and the mechanical parts are more likely to come apart, so the sensitivity is also likely to decrease. Therefore, the position of the internal fixation lamp may be set so that the scan position of the measurement light at the time of additional imaging is close to the center of the objective lens. As a result, the quality of the additionally captured image is improved.

[0086] When an instruction to set the additional imaging condition is input (S8: YES), the CPU 31 sets the additional imaging condition 78 instructed by the user and causes it to be displayed on the monitor 37. Then, the process proceeds to S11.

[0087] Next, the CPU 31 determines whether an instruction for designating the extraction position and the additional imaging position has been input (S11). The user can input an instruction for designating the extraction position and the additional imaging position (for example, an instruction to move the position) to the OCT apparatus 1 via the operation unit 38 or the like. For example, the CPU 31 may recognize the position of the pointer that moves on the two-dimensional front image 70 according to the operation instruction by the user as the position designated by the user. Also, the position on the two-dimensional front image 70 may be designated by a touch panel.

[0088] When the extraction position and the additional imaging position are designated (S11: YES), the CPU 31 moves the extraction position and the additional imaging position (in this embodiment, the position of the line pattern 75 and the position of the additional imaging pattern 78) to the designated positions on the two-dimensional front image 70 displayed on the monitor 37 (S12). That is, in this embodiment, the CPU 31 moves both the extraction position and the additional imaging position in conjunction with each other on the two-dimensional front image 70. Therefore, the user can set the additional imaging position as it is in a state where the internal state of the tissue at the extraction position is confirmed by the two-dimensional tomographic image 5. However, the extraction position and the additional imaging position may be designated (moved) separately.

[0089] Next, the CPU 31 determines whether a trigger for executing additional imaging has been input (S14). In this embodiment, the trigger for additional imaging is input in various ways. For example, after setting the additional imaging position on the two-dimensional front image 70, the user can input an instruction for executing additional imaging as a trigger. Also, the CPU 31 may regard the operation of setting the additional imaging position on the two-dimensional front image 70 as the operation of the trigger for additional imaging. In this case, the user can cause the OCT apparatus 1 to execute additional imaging only by setting the additional imaging position. Also, after the additional imaging position is set, the CPU 31 may compare the front observation image captured in real time with the two-dimensional front image 70, and use as a trigger that the additional imaging position set on the two-dimensional front image 70 coincides with the front observation image.

[0090] If the trigger for additional imaging has not been input (S14: NO), the process returns to S4, and the processes of S4 to S14 are repeated. When the trigger for additional imaging is input (S14: YES), the CPU 31 acquires a frontal observation image that has been captured in real time by the frontal observation optical system 23 (S15). Based on the two-dimensional frontal image 70 and the frontal observation image, the CPU 31 identifies the additional imaging position specified on the two-dimensional frontal image 70, which is a still image, on the frontal observation image captured in real time (S16). Note that the method for identifying the additional imaging position specified on the two-dimensional frontal image 70 on the frontal observation image can be selected as appropriate. In the present embodiment, the CPU 31 performs alignment between the two-dimensional frontal image 70 and the frontal observation image using known image processing or the like, thereby identifying the additional imaging position on the frontal observation image.

[0091] The CPU 31 executes second imaging processing (S17). In the second imaging processing, the CPU 31 executes additional imaging at the additional imaging position identified in S16 in accordance with the additional imaging pattern 78 set in S9 (S17). Specifically, the CPU 31 executes additional imaging of a tomographic image by scanning measurement light on the line of the additional imaging pattern 78 selected by the user and set at the additional imaging position. According to the above processing, the user can cause the OCT apparatus 1 to perform additional imaging at an appropriate position after confirming the internal state of the tissue within the imaging range of the three-dimensional tomographic image 2 using the extracted two-dimensional tomographic image 5. The image quality of the additionally captured tomographic image is less likely to deteriorate compared to the image quality of an image arbitrarily extracted from the three-dimensional tomographic image 2. Therefore, an image of a position that the user wishes to confirm in detail within the range where the three-dimensional tomographic image 2 has been captured is presented to the user more appropriately and with higher image quality.

[0092] Note that the OCT device 1 also performs tracking using a template image and a real-time frontal observation image in the second imaging process (S17) in the same manner as in the above-described first imaging process (see FIG. 4). Here, as the template image serving as the reference for tracking, for example, a frontal observation image (SLO image in this embodiment) captured at the start of tracking, a frontal observation image captured at the timing of the imaging trigger input (release), and an Enface image 3 (see FIG. 2) generated based on the three-dimensional tomographic image 2 can be used.

[0093] Here, which image is used as the template image serving as the reference for tracking may be automatically set based on the imaging conditions when the three-dimensional tomographic image 2 is captured in the first imaging process. For example, when the addition average process is being performed in the first imaging process, since there is a low possibility that distortion and defects will occur in the Enface image 3 generated based on the three-dimensional tomographic image 2, the Enface image 3 may be used as the template image. On the other hand, when the addition average process is not being performed in the first imaging process, since distortion and defects may occur in the Enface image 3, a frontal observation image captured at the start of tracking or a frontal observation image captured at the timing of release may be used as the template image.

[0094] The CPU 31 links the data of the additional captured image captured in the second capturing process (S17) to the data of the three-dimensional tomographic image captured in the first capturing process (S1), and stores it in a storage device (for example, NVM 34 or the like). Next, the CPU 31 executes additional captured image display control processing (S19). In the additional captured image display control processing, the two-dimensional tomographic image 5 extracted from the three-dimensional tomographic image 2 and the additional captured image linked and stored to the data of the three-dimensional tomographic image 2 are simultaneously or switched and displayed on the monitor 37 together with the data related to the three-dimensional tomographic image 2 (for example, at least any one of the three-dimensional tomographic image 2 and the analysis result for the three-dimensional tomographic image 2). As an example, in the additional captured image display control processing in the present embodiment, when the CPU 31 causes the monitor 37 to display the data related to the three-dimensional tomographic image 2, the CPU 31 displays a graphical user interface (GUI, for example, an icon) for the user to input a switching instruction between the extracted two-dimensional tomographic image 5 and the additional captured image. When the GUI is operated, the CPU 31 switches the display between the extracted two-dimensional tomographic image 5 and the additional captured image. In this case, since each of the images linked to each other is smoothly switched, the convenience for the user is further improved.

[0095] Note that conventionally, even if the data was obtained for the same eye to be examined, the data related to the three-dimensional tomographic image 2 and the data of the additional captured image were not stored in a linked state. As a result, even in a viewer that displays the image captured by the OCT apparatus 1 and the analysis result for the image, etc., the data related to the three-dimensional tomographic image 2 and the data of the additional captured image were treated as completely different data (that is, data indicating the results of completely different examinations). On the other hand, in the present embodiment, the data related to the three-dimensional tomographic image 2 and the data of the additional captured image are stored in a linked state. Therefore, not only on the confirmation screen for allowing the user to confirm the imaging result, but also in the above-described viewer, the two-dimensional tomographic image 5 extracted from the three-dimensional tomographic image 2 and the additional captured image are simultaneously or switched and displayed based on the link together with the data related to the three-dimensional tomographic image 2.

[0096] The technology disclosed in the above embodiment is only an example. Therefore, it is also possible to change the technology exemplified in the above embodiment. For example, it is also possible to execute only a part of the plurality of technologies exemplified in the above embodiment.

[0097] Note that the first imaging process shown in FIG. 4 is an example of the "first imaging step". The process of extracting and displaying the two-dimensional tomographic image in S6 of FIG. 4 and S46 of FIG. 7 is an example of the "extraction display step". The process of setting the additional imaging position in S11, S12 of FIG. 4 and S44 of FIG. 7 is an example of the "additional imaging position setting step". The second imaging process shown in S15 to S17 of FIG. 4 is an example of the "second imaging step". The process of setting the line pattern in S4, S5 of FIG. 4 is an example of the "line pattern setting step". The process of setting the additional imaging pattern in S8, S9 of FIG. 4 is an example of the "additional imaging pattern setting step". The process of displaying the two-dimensional frontal image in S31 to S42 of FIG. 7 is an example of the "frontal image display step". The process of inputting an instruction from the user in S11 of FIG. 4 is an example of the "position input step". The process of displaying the extraction position and the additional imaging position in S6, S9, S12 of FIG. 4 and S45 of FIG. 7 is an example of the "position display step". The process of inputting the three-dimensional tomographic image 2 into the mathematical model in S41 of FIG. 7 is an example of the "image input step". The process of acquiring the confidence information in S42 of FIG. 7 is an example of the "confidence information acquisition step".

Explanation of Signs

[0098] 1 OCT device 2 Three-dimensional tomographic image 3 Enface image 5 Two-dimensional tomographic image 23 Front observation optical system 31 CPU 34 NVM 37 Monitor 50 Front observation image 70 Two-dimensional frontal image 73 Analysis map 74 Confidence display image 75 Line pattern 78 Additional shooting pattern 80 Additional shooting pattern selection section

Claims

1. An OCT device that captures a tomographic image of the tissue of an eye to be examined by processing an OCT signal generated by reference light and measurement light irradiated onto the eye to be examined, wherein a control unit of the OCT device performs a first imaging step of capturing a three-dimensional tomographic image of the tissue by irradiating the measurement light onto a two-dimensional measurement region that spreads in a direction intersecting the optical axis of the measurement light; a front image display step of causing a display unit to display a two-dimensional front image of the tissue when viewed from a direction along the optical axis of the measurement light, after the three-dimensional tomographic image has been captured; a position input step of inputting an instruction from a user for designating both an extraction position for extracting a two-dimensional tomographic image from the three-dimensional tomographic image and an additional imaging position for the tomographic image, on the displayed two-dimensional front image; a position display step of overlapping and displaying both the extraction position and the additional imaging position on the two-dimensional front image, and moving both the extraction position and the additional imaging position in conjunction with each other on the two-dimensional front image in response to an instruction input by the user, thereby setting the extraction position and the additional imaging position; an extraction display step of extracting a two-dimensional tomographic image from the set extraction position in the three-dimensional tomographic image and displaying it on the display unit; a trigger input step of inputting a trigger for executing additional imaging while the two-dimensional tomographic image is being displayed on the display unit; a second imaging step of performing additional imaging of a tomographic image by irradiating the measurement light onto the set additional imaging position when a trigger for additional imaging is input; characterized in that the OCT device executes the above steps.

2. The OCT device according to Claim 1, wherein the control unit further executes a line pattern setting step of setting any one of a plurality of types of line patterns in which at least any one of the arrangement, number, and shape of lines is different from each other, for the two-dimensional measurement region from which the three-dimensional tomographic image has been obtained; wherein in the extraction display step, a two-dimensional tomographic image on the lines of the set line pattern is extracted from the three-dimensional tomographic image and displayed on the display unit.

3. The OCT device according to Claim 1 or 2, wherein the control unit further executes an additional imaging condition setting step of setting imaging conditions for additional imaging of a tomographic image. In the second imaging step, an OCT apparatus is characterized in that additional imaging is performed according to the set imaging conditions at the additional imaging position.

4. The OCT apparatus according to claim 3, wherein the imaging conditions that can be set in the additional imaging condition setting step include an imaging pattern for additional imaging of a tomographic image. An OCT apparatus characterized by this.

5. The OCT apparatus according to any one of claims 1 to 4, wherein the control unit, further executes an analysis step of analyzing the three-dimensional tomographic image captured in the first imaging step and generating an analysis map that two-dimensionally shows the distribution of the analysis results, In the front image display step, an OCT apparatus is characterized in that the analysis map is displayed on the display unit as the two-dimensional front image.

6. The OCT apparatus according to any one of claims 1 to 5, wherein the control unit, An OCT apparatus is characterized in that at least one of an extraction position for extracting the two-dimensional tomographic image from the three-dimensional tomographic image and the additional imaging position is set based on the analysis result of the three-dimensional tomographic image.

7. The OCT apparatus according to any one of claims 1 to 6, wherein the control unit, For the tissue of the same eye to be examined, the data of the three-dimensional tomographic image captured in the first imaging step and the data of the additional imaging image captured in the second imaging step are linked and stored in a storage device, An OCT apparatus is characterized in that the two-dimensional tomographic image extracted from the three-dimensional tomographic image and the additional imaging image linked and stored in the three-dimensional tomographic image are simultaneously or switched and displayed on the display unit together with the data related to the three-dimensional tomographic image.

8. An imaging control program executed by an OCT apparatus that captures a tomographic image of the tissue of the eye to be examined by processing an OCT signal generated by a reference light and a measurement light irradiated on the eye to be examined, By the imaging control program being executed by the control unit of the OCT apparatus, A first imaging step of irradiating the measurement light on a two-dimensional measurement region that spreads in a direction intersecting the optical axis of the measurement light to capture a three-dimensional tomographic image of the tissue, A front image display step of displaying, on a display unit, a two-dimensional front image of the tissue when viewed from a direction along the optical axis of the measurement light, where the three-dimensional tomographic image has been captured. A position input step of inputting an instruction from a user for designating both an extraction position for extracting a two-dimensional tomographic image from the three-dimensional tomographic image and an additional imaging position of the tomographic image on the displayed two-dimensional front image; A position display step of overlapping both the extraction position and the additional imaging position on the two-dimensional front image and moving both the extraction position and the additional imaging position in conjunction with each other on the two-dimensional front image in accordance with an instruction input by the user, thereby setting the extraction position and the additional imaging position; An extraction display step of extracting a two-dimensional tomographic image from the set extraction position among the three-dimensional tomographic images and displaying the extracted image on a display unit; A trigger input step of inputting a trigger for executing additional imaging while the two-dimensional tomographic image is being displayed on the display unit; A second imaging step of performing additional imaging of the tomographic image by irradiating the set additional imaging position with the measurement light when a trigger for additional imaging is input; A imaging control program, characterized by causing the OCT apparatus to execute the above steps.

Images