JP2019213609A - Imaging device and control method thereof - Google Patents

Abstract

To provide a specification capable of switching a mode between a plurality of imaging modes with different imaging range while avoiding size increase of a device.SOLUTION: An imaging device comprises: a coupler 1113 for branching a light from a light source 1111 into a measurement light and a reference light; an optical member of an optical path L2 for radiating a line-shaped measurement light to an eyeground Er of an eye to be examined E being a measurement target; a line camera 1142 for detecting an interference light which is acquired by interference between a return light of the line-shaped measurement light from the eyeground Er of the eye to be examined E, and the line-shaped reference light; and a whole control part 1310 for changing a line width of the measurement light to be radiated to the eyeground Er of the eye to be examined E by the optical member of the optical path L2, for every imaging mode in the plurality of imaging modes in which the imaging range of the eyeground Er of the eye to be examined E is different from each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image capturing apparatus that captures an image of a measurement target using light from a light source and a control method thereof.

  Optical coherence tomography (hereinafter, referred to as “OCT”) has been put to practical use as a method for non-destructively and non-invasively acquiring a tomographic image of a measurement target. In recent years, particularly in the field of ophthalmology, taking a tomographic image of the fundus of a subject's eye using this OCT technique has become widespread from research to clinical sites. In the OCT apparatus using the OCT technique, after the light from the light source is split into the measurement light and the reference light, the return light of the measurement light from the measurement target and the reference light interfere with each other, so that the depth of the measurement target is reduced. The intensity of the interference light in the vertical direction is imaged, and a tomographic image to be measured is obtained.

  Many OCT devices that are currently widely used irradiate a measurement target with a spot-like measurement light, combine two or more optical deflection elements such as a galvano scanner or a resonance scanner, and two-dimensionally measure the area of the measurement target with the measurement light. What to scan. At this time, there are a 3D shooting mode for shooting a wide range and a cross-scan mode for shooting with high image quality by increasing the number of added images in a narrow range, depending on the shooting range and image quality desired by the operator.

  Recently, for example, a line OCT device described in Non-Patent Document 1 has been developed as an OCT device for acquiring a higher-speed and high-quality captured image. Specifically, the line OCT apparatus irradiates a measurement target with linear measurement light, and causes interference between return light of the measurement light from the measurement target and reference light to obtain interference light.

  For example, in fundus examination of the subject's eye, there are two cases: one wants to capture a wide range from the macula to the vicinity of the nipple, and one wants to capture a narrow area near the macula with high image quality in order to detect the eye disease early and start treatment. is there. In this case, there is a demand for an OCT apparatus capable of switching between a wide-angle photographing mode and a narrow-angle photographing mode for photographing. For example, in Japanese Patent Application Laid-Open No. H11-163, in switching an imaging mode, an objective lens used in an OCT apparatus is exchanged and switched with an objective lens having a different focal length, thereby changing an imaging range and the resolution of the imaging range to perform imaging. Technology has been proposed.

JP 2017-64378 A

DJ Fechtig, B. Grajciar, T. Schmoll, C. Blatter, RM Werkmeister, W. Drexler, and R. a Leitgeb, "Line-field parallel swept source MHz OCT for structural and functional retinal imaging.," Biomed. Opt. Express, vol. 6, no. 3, pp. 716? 35, Mar. 2015.

  When the focal length of the objective lens that determines the working distance with the subject's eye is changed as in the technique described in Patent Literature 1, for example, the normal shooting mode (wide view angle shooting mode) is switched to the narrow view angle shooting mode. In this case, the working distance is changed at the same time, and the focus position on the fundus is also changed. When the working distance is changed, the optical path length of the measuring light in the OCT apparatus is also changed, and as a result, the optical path length of the reference light also needs to be changed. That is, in the related art, before and after switching of the imaging mode in which the imaging range is different, since the reference mirror and the like need to be largely moved with the change in the optical path length of the reference light based on the change in the optical path length of the measurement light, There has been a problem that the size of the apparatus is increased.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a mechanism capable of performing photographing by switching a plurality of photographing modes having different photographing ranges while avoiding an increase in the size of the apparatus.

The photographing device of the present invention is a light branching unit that branches light from a light source into measurement light and reference light, an irradiation unit that irradiates the measurement target with the linear measurement light, and the light from the measurement target. Detecting means for detecting interference light obtained by causing the return light of the line-shaped measurement light and the line-shaped reference light to interfere with each other; and And control means for performing control to change a line width of the measurement light irradiated to the measurement object by the irradiation means.
Further, the present invention includes a control method of the above-described photographing device.

  Advantageous Effects of Invention According to the present invention, it is possible to perform imaging in which a plurality of imaging modes having different imaging ranges are switched while avoiding an increase in the size of the apparatus.

FIG. 1 is a diagram illustrating an example of a schematic configuration of a photographing device according to an embodiment of the present invention. 6 is a flowchart illustrating an example of a processing procedure in a control method of the imaging device according to the embodiment of the present invention. FIG. 3 is a diagram illustrating an example of a tomographic image of a fundus oculi generated in the image generation processing in step S18 illustrated in FIG. 2. 3 is a flowchart illustrating an example of a detailed processing procedure of a shooting mode setting process in step S11 illustrated in FIG. 2. FIG. 7 shows the embodiment of the present invention, and is a diagram illustrating an example of the arrangement of optical members in an optical path L2 in a normal shooting mode and in a narrow-angle shooting mode. FIG. 14 is a diagram illustrating a first modification of the embodiment of the present invention, and illustrating an example of the arrangement of optical members on an optical path L3 in a normal shooting mode and in a narrow-angle shooting mode. FIG. 10 is a diagram illustrating a second modification of the embodiment of the present invention and illustrating an example of interference light incident on the line camera in FIG. 1.

  Hereinafter, an embodiment (embodiment) for carrying out the present invention will be described with reference to the drawings. Note that the embodiments of the present invention described below do not limit the present invention described in the claims, and all combinations of the features described as the embodiments of the present invention are not limited to the present invention. Is not necessarily essential to the solution of the above.

(Schematic configuration of photographing device)
FIG. 1 is a diagram illustrating an example of a schematic configuration of a photographing apparatus 1000 according to an embodiment of the present invention. Here, in the embodiment of the present invention, as the imaging apparatus 1000, an optical coherence tomography apparatus (OCT apparatus) that captures a tomographic image of the eye E to be measured (more specifically, the fundus Er of the eye E). An example in which is applied will be described.

  As shown in FIG. 1, the imaging device 1000 includes an optical head unit 1100, an electric stage unit 1200, a control / processing unit 1300, an input unit 1400, and a display unit 1500. FIG. 1 shows a cross section of the eye E to be measured as a measurement target when the eyeball is viewed from the side.

  The optical head unit 1100 has optical paths L1 to L6 in which each optical element is arranged on the optical path. Various types of light passing through the optical head unit 1100 may be transmitted through an optical fiber, or may be transmitted through the air via optical members.

  A light source 1111, a light amount adjusting mechanism 1112, and a coupler 1113 are arranged on the optical path L <b> 1.

  As the light source 1111, for example, an SS light source of a wavelength sweep type capable of outputting light having a center wavelength of 1060 nm and a wavelength band of 90 nm is used. In the present embodiment, the light source 1111 is not limited to the wavelength-swept SS light source. For example, an SLD (Super Luminescent Diode) that can output light having a center wavelength of 850 nm and a wavelength band of 100 nm is used. It is also possible. The light amount adjustment mechanism 1112 can increase or decrease the light amount of the light output from the light source 1111 or turn off the light amount. The coupler 1113 is an optical splitting unit that splits the light output from the light source 1111 and the light amount of which is adjusted by the light amount adjustment mechanism 1112 into measurement light and reference light.

  In the optical path L2, an optical member or the like related to a measuring light transmitting unit corresponding to an irradiating unit that irradiates a line-shaped measuring light to the eye E to be measured (more specifically, the fundus Er of the eye E) to be measured. Is arranged.

  Specifically, the measurement light branched by the coupler 1113 propagates from the fiber end 1120 to the air, and is guided to the collimator lens 1121 and the cylindrical lens 1122. The collimator lens 1121 is an optical member that converts incident measurement light into parallel light. The cylindrical lens 1122 is an optical member (line measurement light forming member) that forms a linear measurement light from the measurement light incident via the collimator lens 1121. After that, the linear measurement light is guided to the beam splitter 1101 via the collimator lens 1123. Further, the linear measurement light passes through a beam splitter 1101 and is focused via a focus lens 1124, a shutter 1125, a galvano scanner 1126, a relay lens 1127, a dichroic mirror 1102, a dichroic mirror 1103, and an objective lens 1104. Guided to optometry E.

  Here, the focus lens 1124 is an optical member for adjusting the focus of the measurement light to the fundus Er. The galvano scanner 1126 scans in the plane of the fundus Er perpendicular to the major axis direction (X direction shown in FIG. 1) of the linear measurement light generated via the cylindrical lens 1122 (shown in FIG. 1). The mirror surface is scanned in the Y direction). In the present embodiment, the focus lens 1124 and the galvano scanner 1126 include drive mechanisms (not shown), and the control and processing unit 1300 controls these drive mechanisms so that the drive can be controlled.

  The dichroic mirror 1102 is a dichroic mirror that branches the optical path L2 and the optical path L6, and has a property of transmitting measurement light when it enters. The dichroic mirror 1103 is a dichroic mirror that branches the optical path L2 and the optical path L5, and has a characteristic of reflecting when the measurement light enters. Note that the transmission / reflection characteristics of the dichroic mirror 1102 and the dichroic mirror 1103 may be reversed depending on the arrangement of the optical system.

  Furthermore, when the linear measurement light that has entered the fundus Er of the eye E is reflected and scattered by the fundus Er, the light is returned as measurement light by the measurement light that has entered the fundus Er via the objective lens 1104. The light is guided to the beam splitter 1101 through the same optical path L2. Then, this return light is reflected by the beam splitter 1101 and guided to the optical path L4.

  In the optical path L3, an optical member or the like related to a reference light transmitting unit that transmits the reference light branched by the coupler 1113 is disposed.

  Specifically, the reference light branched by the coupler 1113 propagates from the fiber end 1130 to the air, and is guided to the collimator lens 1131 and the ND filter 1132. The collimator lens 1131 is an optical member that converts incident reference light into parallel light. The ND filter 1132 is an optical member for adjusting the amount of reference light incident from the collimator lens 1131. After that, the reference light passes through the reference mirror 1133 for changing the optical path length of the reference light in the optical path L2, passes through the return mirror 1134, the cylindrical lens 1135, the collimator lens 1136, passes through the beam splitter 1101, and passes through the optical path L2. It is led to L4. In the present embodiment, the reference mirror 1133 includes drive mechanisms (not shown), and the control / processing unit 1300 controls these drive mechanisms, so that the reference mirror 1133 moves and changes the optical path length of the reference light. It is configured to be possible. Further, the cylindrical lens 1135 is an optical member (line reference light forming member) that forms a linear reference light from the reference light incident via the return mirror 1134.

  In the optical path L4, an optical member or the like related to interference light transmitting means for transmitting interference light obtained by causing the return light of the measurement light guided from the optical path L2 to interfere with the reference light guided from the optical path L3 is arranged. ing.

  Specifically, the return light of the linear measurement light guided from the optical path L2 via the beam splitter 1101 and the linear reference light guided from the optical path L3 via the beam splitter 1101 interfere with each other. Light (linear interference light) is synthesized. The interference light obtained by the interference is guided to the line camera 1142 via the imaging lens 1141. The line camera 1142 is a detecting unit that detects the incident interference light as an interference signal that is an electric signal. The interference signal obtained by the line camera 1142 is output to the control / processing unit 1300.

  In the optical path L5, an optical member or the like related to an anterior segment observation light transmission unit that transmits anterior segment observation light for observing the anterior segment of the eye E to be examined is arranged. The optical path L5 is an optical path for capturing an image of the anterior segment of the eye E and acquiring an alignment image for adjusting the working distance between the optical head 1100 and the eye E.

  Specifically, when an anterior segment observation light emitted from an anterior segment illumination LED light source (not shown) is reflected by the anterior segment of the eye E, the reflected light is transmitted through the objective lens 1104 and the dichroic mirror 1103. Incident on the lens unit 1151. After that, the reflected light of the anterior ocular segment observation light is imaged on the camera by the imaging unit 1153 via the lens unit 1151 and the Fresnel lens 1152 arranged at a position conjugate with the pupil of the eye E to be inspected. Then, an anterior ocular segment observation signal obtained by the camera of the imaging unit 1153 is output to the control and processing unit 1300. Note that the camera in the imaging unit 1153 has a conjugate relationship with the pupil of the eye E and the Fresnel lens 1152.

  In the optical path L6, an optical member or the like related to a fundus observation light / fixation light transmission unit that transmits fundus observation light for observing the fundus of the eye E and fixation light for promoting fixation of the eye E is arranged. ing. The optical path L <b> 6 is an optical path for presenting a fixation target to the eye E and obtaining a fundus front observation image of the eye E.

  Fixation light, which is visible light emitted from the fixation lamp light source 1162, is reflected by the dichroic mirror 1163, and transmitted through the lens unit 1164 and the dichroic mirror 1102 in the same optical path as the optical path L2. Specifically, the fixation light is reflected by the dichroic mirror 1103 via the dichroic mirror 1102, and is guided to the fundus Er of the eye E via the objective lens 1104. Thereby, the fixation target based on the fixation light is presented to the eye E to be examined. Here, the presentation position of the fixation target can be moved to a position where the operator wants to photograph by operating the input unit 1400 while looking at the display unit 1500.

  The fundus oculi observation light emitted from the fundus oculi observation light source 1161 passes through the dichroic mirror 1163, and is transmitted through the same optical path as the optical path L2 via the lens unit 1164 and the dichroic mirror 1102. Specifically, the fundus observation light is reflected by the dichroic mirror 1103 via the dichroic mirror 1102, and is guided to the fundus Er of the eye E via the objective lens 1104. The reflected light of the fundus oculi observation light reflected by the fundus Er of the eye E is guided to the lens unit 1164 via the objective lens 1104, the dichroic mirror 1103, and the dichroic mirror 1102. Then, the reflected light of the fundus oculi observation light guided to the lens unit 1164 is reflected by the perforated mirror arranged in the lens unit 1164, and is guided to the fundus oculi observation light receiving unit 1165. In the lens unit 1164, a galvano mirror and a polygon mirror (not shown) are arranged, and scan light rays in a two-dimensional direction. The fundus oculi observation light receiving unit 1165 detects the reflected light of the received fundus oculi observation light as a fundus oculi observation signal, and outputs this to the control / processing section 1300.

  The electric stage 1200 moves the optical head 1100 appropriately in the X, Y, and Z directions based on the control of the control / processing section 1300.

  The control / processing unit 1300 controls the optical head unit 1100, the motorized stage unit 1200, and the display unit 1500 based on information input from the input unit 1400, for example, to control the operation of the image capturing apparatus 1000 as a whole. Performs various processes. The control / processing section 1300 includes an overall control section 1310, an image generation section 1320, a display control section 1330, and a storage section 1340.

  The overall control unit 1310 controls the overall operation of the imaging device 1000 and performs various operations. The image generation unit 1320 obtains an interference signal from the line camera 1142, performs signal processing, and generates a tomographic image of the eye E (more specifically, the fundus Er of the eye E). At this time, the image generation unit 1320 performs signal processing including frequency analysis such as Fourier transform on the interference signal acquired from the line camera 1142, and generates a tomographic image. Further, the image generation unit 1320 obtains an anterior ocular segment observation signal from the imaging unit 1153 and performs signal processing to generate an anterior ocular segment observation image of the eye E to be inspected. And performs signal processing to generate a fundus frontal observation image of the subject's eye E. The display control unit 1330 controls the display unit 1500 to display the tomographic image, the anterior ocular segment observation image, and the fundus frontal observation image obtained by the image generation unit 1320, as well as information input from the input unit 1400 and various types of information. Control is performed to display information and the like obtained by the control and processing on the display unit 1500. In the present embodiment, a display control unit 1330 having a configuration different from that of the general control unit 1310 is provided. For example, the functions of the display control unit 1330 are included in the general control unit 1310 and are integrated by the general control unit 1310. The control may be performed. The storage unit 1340 stores programs, various information, and various data necessary for performing control and processing by the control and processing unit 1300, and is obtained by performing control and processing by the control and processing unit 1300. The stored various information and various data are stored.

  The input unit 1400 is a component operated by the operator of the imaging device 1000 when inputting various information.

  The display unit 1500 displays the tomographic image, the anterior eye observation image, and the fundus front observation image obtained by the image generation unit 1320 based on the control of the display control unit 1330, and displays information input from the input unit 1400, Information and the like obtained by various controls and processes are displayed.

(Method of controlling photographing device)
FIG. 2 is a flowchart illustrating an example of a processing procedure in the control method of the imaging device 1000 according to the embodiment of the present invention.

  First, when the operator selects and inputs a photographing mode via the input unit 1400, in step S <b> 11, based on the photographing mode input from the input unit 1400, the overall control unit 1310 generates a tomographic image of the fundus Er of the eye E to be examined. To set the shooting mode according to. Here, in the present embodiment, it is assumed that a plurality of photographing modes in which the photographing range of the fundus Er of the eye E to be measured is different can be set. Specifically, in the present embodiment, as a plurality of photographing modes, a normal photographing mode (first photographing mode) for photographing a wide range of the fundus Er and a narrow angle of view photographing mode (first photographing mode) for photographing a narrow range of the fundus Er. It is assumed that there is a second photographing mode having a smaller photographing range than the photographing mode of (2).

  Thereafter, when the subject sets his / her head at a predetermined position and the operator inputs an instruction to start imaging via the input unit 1400, subsequently, in step S12, the overall control unit 1310 sets the subject's A process of starting imaging of the eye E is performed.

  Subsequently, in step S13, the image generation unit 1320 performs signal processing on the anterior eye observation signal output from the imaging unit 1153 to generate an anterior eye observation image of the eye E to be inspected. The control for displaying the anterior eye observation image on the display unit 1500 is performed.

  Thereafter, when the operator who has viewed the anterior ocular segment observation image displayed on the display unit 1500 in real time inputs an alignment instruction via the input unit 1400, subsequently, in step S14, the overall control unit 1310 detects this. I do. Then, the overall control unit 1310 controls the drive of the electric stage unit 1200 based on the alignment instruction, adjusts the position of the optical head unit 1100, and adjusts the working distance. Here, the position of the optical head unit 1100 can be adjusted in the X, Y, and Z directions with respect to the eye E by the electric stage unit 1200.

  Subsequently, in step S15, the image generation unit 1320 performs signal processing on the fundus observation signal output from the fundus observation light receiving unit 1165 to generate a fundus front observation image, and outputs the interference signal output from the line camera 1142. The signal processing is performed to generate a tomographic image of the fundus Er. Then, the display control unit 1330 performs control to display the fundus front observation image and the tomographic image of the fundus Er on the display unit 1500.

  After that, when the operator who looks at the fundus front observation image and the tomographic image of the fundus Er displayed on the display unit 1500 inputs a photographing position of the tomographic image and an instruction for luminance adjustment via the input unit 1400, the process proceeds to step In S16, the overall control unit 1310 detects this. Then, the overall control unit 1310 drives and controls the reference mirror 1133 and the focus lens 1124 based on an instruction for adjusting the shooting position of the tomographic image and the brightness. Thereby, the alignment of the tomographic image and the luminance adjustment that makes the luminance of the tomographic image the brightest are performed.

  Thereafter, when the subject inputs an actual photographing instruction, subsequently, in step S17, the overall control unit 1310 performs a tomographic image photographing process on the fundus Er of the eye E under the set photographing conditions.

  Subsequently, in step S18, the image generation unit 1320 generates a tomographic image of the fundus Er based on the interference signal from the line camera 1142 obtained by the imaging processing in step S17. After that, the display control unit 1330 performs control to display the tomographic image of the fundus Er generated in this step on the display unit 1500.

FIG. 3 is a diagram showing an example of a tomographic image of the fundus Er generated in the image generation processing in step S18 shown in FIG.
Specifically, FIG. 3A shows an example of a tomographic image obtained in a normal imaging mode in which the fundus Er is photographed in a wide range, and FIG. 3B shows narrow-angle photographing in which a narrow range of the fundus Er is photographed. 5 shows an example of a tomographic image obtained in a mode.

  Then, when the processing in step S18 ends, the processing in the flowchart illustrated in FIG. 2 ends.

Next, a detailed processing procedure of the shooting mode setting processing in step S11 shown in FIG. 2 will be described.
FIG. 4 is a flowchart illustrating an example of a detailed processing procedure of the shooting mode setting processing in step S11 illustrated in FIG. It should be noted that the flowchart shown in FIG. 4 shows details of the processing in the narrow-angle shooting mode of the normal shooting mode and the narrow-angle shooting mode in the present embodiment.

  FIG. 5 shows an embodiment of the present invention, and is a diagram illustrating an example of the arrangement of optical members in the optical path L2 in the case of the normal shooting mode and the case of the narrow angle-of-view shooting mode. Specifically, FIG. 5A shows an example of the arrangement of the optical members in the optical path L2 in the normal shooting mode, and FIG. 5B shows the arrangement of the optical members in the optical path L2 in the narrow view angle shooting mode. An example is shown. 5, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

  First, in step S111 in FIG. 4, when the operator selects and inputs a shooting mode via the input unit 1400, the overall control unit 1310 detects this and performs a process of selecting a corresponding shooting mode. Here, in the present embodiment, it is assumed that the plurality of selectable shooting modes include the above-described normal shooting mode and the narrow shooting angle shooting mode.

  In step S111, when the normal photographing mode for photographing the fundus Er in a wide range is selected, the process proceeds to step S114, and the overall control unit 1310 controls the arrangement of the optical members in the optical path L2 illustrated in FIG. Then, the normal photographing mode setting process is performed. Thereafter, the flowchart in FIG. 4 ends, and the process proceeds to the process in step S12 in FIG.

  Specifically, in the present embodiment, the cylindrical lens 1122a shown in FIG. 5A and the cylindrical lens 1122b shown in FIG. 5B are provided as the cylindrical lens 1122 that can be inserted into the optical path L2 of the measurement light shown in FIG. It is assumed that The cylindrical lens 1122a shown in FIG. 5A is a first line measurement light forming member having a shorter focal length than the cylindrical lens 1122b shown in FIG. 5B. The cylindrical lens 1122b shown in FIG. 5B is a second line measurement light forming member having a longer focal length than the cylindrical lens 1122a shown in FIG.

  Then, in the case of the normal photographing mode, as shown in FIG. 5A, the overall control unit 1310 performs control for inserting the cylindrical lens 1122a into the optical path L2 and arranging it at an appropriate position. That is, the overall control unit 1310 performs control so that the line width MW1 of the measurement light in the normal shooting mode is wider than the line width MW2 of the measurement light in the narrow angle of view shooting mode.

On the other hand, in step S111, when the narrow-angle photographing mode for photographing the narrow range of the fundus Er is selected, the process proceeds to step S112.
In step S112, the overall control unit 1310 controls the arrangement of the optical members on the optical path L2 illustrated in FIG. 5B. Specifically, in the case of the narrow angle-of-view photographing mode, the overall control unit 1310 performs control to insert the cylindrical lens 1122b into the optical path L2 and to arrange the cylindrical lens 1122b at an appropriate position as shown in FIG. 5B. In this case, the general control unit 1310 inserts the cylindrical lens 1122b having the changed focal length and the changed arrangement into the optical path L2 in the case of the normal shooting mode shown in FIG. That is, in the case of the narrow angle-of-view shooting mode, the overall control unit 1310 performs control to make the line width MW2 of the measurement light narrower than the line width MW1 of the measurement light in the case of the normal shooting mode.

Here, consider a case where the operator switches from the normal shooting mode to the narrow angle-of-view shooting mode.
In this case, the overall control unit 1310 switches from the cylindrical lens 1122a having a short focal length shown in FIG. 5A to the cylindrical lens 1122b having a long focal length shown in FIG. Perform switching control. As shown in FIG. 5, the distance from the collimator lens 1121 for converting the measurement light output from the fiber end 1120 into parallel light to the surface of the cylindrical lens 1122 on the collimator lens 1121 side is defined as p2. The distance from the collimator lens 1121 side surface of the cylindrical lens 1122 to the collimator lens 1123 including its thickness is defined as p1. The distance from the collimator lens 1121 to the collimator lens 1123, which is the sum of the distance p1 and the distance p2, is P.

  In the case of the normal photographing mode, the distance from the collimator lens 1121 to the surface of the cylindrical lens 1122a on the collimator lens 1121 side is defined as p2a. In the case of the normal photographing mode, the distance from the surface of the cylindrical lens 1122a on the collimator lens 1121 side to the collimator lens 1123 including the optical thickness of the lens (the lens thickness is converted to the actual distance by the refractive index) is p1a. I do.

  In the case of the narrow angle-of-view photographing mode, the distance from the collimator lens 1121 to the surface of the cylindrical lens 1122b on the collimator lens 1121 side is defined as p2b. In the case of the narrow angle-of-view photographing mode, the distance from the collimator lens 1121 side surface of the cylindrical lens 1122b to the collimator lens 1123 including the optical thickness of the lens is p1b.

In each shooting mode in the present embodiment, the following expressions (1) to (3) are satisfied.
Pa = p1a + p2a (1)
Pb = P1b + p2b (2)
P = Pa = Pb (3)

  From the equation (3), even if the cylindrical lens 1122 having a different focal length is switched for each shooting mode having a different shooting range, the entire optical path length in the optical path L2 of the measurement light does not change. Therefore, it is not necessary to change the optical path length of the reference light in the optical path L3 when capturing a tomographic image. That is, since it is not necessary to move the reference mirror 1133 largely when capturing a tomographic image, it is possible to avoid an increase in the size of the imaging device 1000.

  When the operator switches from the normal imaging mode to the narrow angle-of-view imaging mode, the overall control unit 1310 performs control to switch from the cylindrical lens 1122a having a short focal length to the cylindrical lens 1122b having a short focal length. In this case, in the narrow angle-of-view photographing mode, as shown in FIG. 5B, the line width MW2 of the linear measurement light applied to the fundus Er of the eye E becomes narrow, and the power density of the measurement light increases. Therefore, a tomographic image can be captured with high sensitivity.

  Although FIGS. 1 and 5 illustrate an example in which one lens is applied as the cylindrical lens 1122, the present embodiment is not limited to this mode. In the present embodiment, for example, an optical system in which a plurality of lenses are combined can be applied.In this case, in addition to switching the cylindrical lens to a cylindrical lens having a different focal length, adding or deleting a cylindrical lens In addition, a mode in which the line width in the measurement light is changed can be adopted.

  Then, in the present embodiment, when the process of step S112 is completed, the process proceeds to step S114, and a process of setting a narrow angle of view shooting mode based on the arrangement of the optical members in the optical path L2 illustrated in FIG. 5B is performed. Thereafter, the flowchart in FIG. 4 ends, and the process proceeds to the process in step S12 in FIG.

  Next, a modification of this embodiment will be described.

First, a first modification of the present embodiment will be described.
FIG. 6 illustrates a first modification of the embodiment of the present invention, and is a diagram illustrating an example of the arrangement of the optical members on the optical path L3 in the case of the normal shooting mode and the case of the narrow angle-of-view shooting mode. Specifically, FIG. 6A shows an example of the arrangement of the optical members in the optical path L3 in the normal shooting mode, and FIG. 6B shows the arrangement of the optical members in the optical path L3 in the narrow view angle shooting mode. An example is shown. 6, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

  Specifically, in the first modification of the present embodiment, the cylindrical lens 1135a shown in FIG. 6A and the cylindrical lens 1135a shown in FIG. 6B as the cylindrical lens 1135 insertable into the optical path L3 of the reference light shown in FIG. It is assumed that a cylindrical lens 1135b is provided. A cylindrical lens 1135a shown in FIG. 6A is a first line reference light forming member having a shorter focal length than the cylindrical lens 1135b shown in FIG. 6B. The cylindrical lens 1135b shown in FIG. 6B is a second line reference light forming member having a longer focal length than the cylindrical lens 1135a shown in FIG. 6A.

  Then, in the normal photographing mode, as shown in FIG. 6A, the overall control unit 1310 performs control for inserting the cylindrical lens 1135a into the optical path L3 and disposing the cylindrical lens 1135a at an appropriate position. That is, the overall control unit 1310 performs control to make the line width RW1 of the reference light wider in the normal shooting mode than the line width RW2 of the reference light in the narrow view angle shooting mode.

  On the other hand, in the case of the narrow angle-of-view shooting mode, the overall control unit 1310 performs control for inserting the cylindrical lens 1135b into the optical path L3 and arranging it at an appropriate position as shown in FIG. 6B. In this case, the overall control unit 1310 inserts the cylindrical lens 1135b with the changed focal length and the changed arrangement into the optical path L3 in the case of the normal shooting mode shown in FIG. 6A. That is, in the case of the narrow angle-of-view shooting mode, the overall control unit 1310 performs control to make the line width RW2 of the reference light narrower than the line width RW1 of the reference light in the normal shooting mode.

  As described above, in the first modified example of the present embodiment, the line width RW of the reference light also changes in the same manner as the line width MW of the measurement light changes. According to the first modification, for example, this is a preferable mode when a sufficient amount of reference light cannot be obtained. That is, in the case of the narrow angle-of-view imaging mode, the power density of the reference light is increased by reducing the line width RW2 of the reference light together with the measurement light, which can contribute to imaging of a highly sensitive tomographic image. Note that, for example, when a sufficient amount of reference light can be secured, it is also possible to apply tomographic image capturing without performing the aspect of the first modified example.

Next, a second modification of the present embodiment will be described.
In the second modification of the present embodiment, the process of step S113 shown in FIG. 4 is performed. That is, in the second modification of the present embodiment, in the case of the narrow-angle-of-view photographing mode, the processing of step S113 is also performed after the processing of step S112 in FIG. 4 ends.

  Specifically, in the second modification of the present embodiment, in step S113 of FIG. 4, the overall control unit 1310 places the line of the interference light between the imaging lens 1141 and the line camera 1142 on the optical path L4 of the interference light. Control for inserting an optical member for increasing the width is performed. That is, in the second modification, the overall control unit 1310 further performs control to increase the line width of the interference light incident on the line camera 1142 in the case of the narrow angle of view shooting mode. Thereby, a high-resolution and high-sensitivity tomographic image can be captured.

  FIG. 7 is a diagram illustrating a second modification of the embodiment of the present invention and illustrating an example of interference light incident on the line camera 1142 in FIG. 1. Here, FIG. 7A shows an example of the interference light 701 incident on the line camera 1142 in the case of the normal shooting mode in the embodiment of the present invention described above. FIG. 7B shows an example of the interference light 702 incident on the line camera 1142 in the case of the narrow-angle photographing mode in the embodiment of the present invention described above (however, when the processing of S113 in FIG. 4 is not performed). Is shown. FIG. 7C shows the interference light 703 incident on the line camera 1142 in the case of the narrow angle-of-view photographing mode in the second modification of the embodiment of the present invention (that is, in the case of performing the processing of S113 in FIG. 4). An example is shown.

  In the state where the process of step S112 in FIG. 4 is performed, as shown in FIG. 7B, the linear interference light 702 is received and photographed using a part of each sensor of the line camera 1142. . Then, when the processing of step S113 in FIG. 4 in the second modification is performed, as shown in FIG. 7C, the interference light 703 having a line width wider than the line width of the interference light 702 shown in FIG. Is received by the line camera 1142 and photographed, so that a tomographic image with higher resolution and higher sensitivity can be photographed.

  Then, in the second modified example of the present embodiment, when the process of step S113 is completed, the process proceeds to step S114, and a process of setting the narrow angle of view shooting mode is performed. Thereafter, the flowchart in FIG. 4 ends, and the process proceeds to the process in step S12 in FIG.

In the embodiment (including the modification) of the present invention described above, the overall control unit 1310 performs the normal imaging mode and the narrow angle-of-view imaging of a plurality of imaging modes in which the imaging range of the fundus Er of the eye E to be measured is different. Control is performed to change the line width of the measurement light irradiated on the fundus Er for each shooting mode in the mode.
According to such a configuration, it is possible to perform shooting in which a plurality of shooting modes having different shooting ranges are switched while avoiding an increase in the size of the apparatus.

  In addition, the amount of light incident on the subject's eye E is limited due to the radiation exposure limit specified in ISO or the like. That is, the limitation on the amount of incident light differs depending on the irradiation range of the measurement light by OCT. When irradiating the fundus Er with the line-shaped measurement light using the line OCT, the power density of the measurement light in the irradiation range becomes smaller than when irradiating the fundus Er with the spot-shaped measurement light, and the imaging sensitivity There is a concern that will decrease. In this regard, in the above-described embodiment of the present invention (including the modified example), in the case of the narrow angle-of-view photographing mode, control is performed to reduce the line width of the linear measurement light irradiated on the fundus Er. However, it is also possible to suppress the decrease in the power density of the measurement light described here.

(Other embodiments)
In the above-described embodiments of the present invention (including the modifications), an example is described in which the fundus Er of the eye E to be inspected is applied as a measurement target, but the present invention is not limited to this embodiment. In the present invention, any object other than the fundus Er of the subject's eye E can be applied as a measurement target as long as it can capture a tomographic image by applying the OCT technique.

  Further, in the above-described embodiments of the present invention (including modified examples), an example is described in which two shooting modes, a normal shooting mode and a narrow angle of view shooting mode, are applied as a plurality of shooting modes having different shooting ranges of a measurement target. However, the present invention is not limited to this mode. In the present invention, a mode in which three or more shooting modes are applied as a plurality of shooting modes having different shooting ranges of the measurement target is also applicable.

The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.
The program and a computer-readable storage medium storing the program are included in the present invention.

  It should be noted that the above-described embodiments of the present invention are merely examples of specific embodiments for carrying out the present invention, and the technical scope of the present invention should not be interpreted in a limited manner. It is. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features.

1000: imaging device, 1100: optical head unit, 1101: beam splitter, 1102, 1103, 1163: dichroic mirror, 1104: objective lens, 1111: light source, 1112: light amount adjustment mechanism, 1113: coupler (fiber coupler), 1120, 1130: Fiber end, 1121, 1123, 1131, 1136: Collimator lens, 1122, 1135: Cylindrical lens, 1124: Focus lens, 1125: Shutter, 1126: Galvano scanner, 1127: Relay lens, 1132: ND filter, 1133: Reference Mirror, 1134: folding mirror, 1141: imaging lens, 1142: line camera, 1151, 1164: lens unit, 1152: Fresnel lens, 1153: imaging unit, 116 : Light source for fundus observation, 1162: light source for fixation lamp, 1165: light receiving unit for fundus observation, 1200: electric stage unit, 1300: control / processing unit, 1310: overall control unit, 1320: image generation unit, 1330: display control Unit, 1340: storage unit, 1400: input unit, 1500: display unit, E: eye to be examined, Er: fundus, L1 to L6: optical path

Claims (7)

Light splitting means for splitting light from the light source into measurement light and reference light,
Irradiating means for irradiating the measurement target with the linear measurement light,
Detection means for detecting interference light obtained by causing the return light of the linear measurement light from the measurement target and the linear reference light to interfere with each other,
Control means for performing control for changing a line width of the measurement light to be irradiated on the measurement target by the irradiation means, for each of a plurality of imaging modes in which the imaging range of the measurement target is different from each other,
An imaging device comprising: The plurality of shooting modes include a first shooting mode and a second shooting mode in which a shooting range is narrower than the first shooting mode,
2. The control device according to claim 1, wherein the control unit performs the control to reduce a line width of the measurement light in the second shooting mode as compared with the first shooting mode. 3. Shooting equipment. The irradiating means includes a first line measuring light forming member and a second line having a longer focal length than the first line measuring light forming member as the line measuring light forming member for forming the linear measuring light. And a measuring light forming member.
3. The imaging apparatus according to claim 2, wherein in the case of the second imaging mode, the control unit performs the control of inserting the second line measurement light forming member into an optical path of the measurement light. 4. apparatus.   4. The control unit according to claim 2, wherein the control unit further controls the line width of the reference light to be narrower in the second shooting mode than in the first shooting mode. 5. An imaging device according to item 1.   5. The control device according to claim 2, wherein in the case of the second shooting mode, the control device further performs control to increase a line width of the interference light incident on the detection device. 6. An imaging device according to item 1.   In a state where the control by the control unit is being performed, the detection unit further includes a generation unit that generates a tomographic image of the measurement target using an interference signal obtained by detecting the interference light in the detection unit. The photographing device according to claim 1. Light branching means for branching light from a light source into measurement light and reference light, irradiation means for irradiating the measurement target with the linear measurement light, and return of the linear measurement light from the measurement target Detecting means for detecting interference light obtained by causing light and the linear reference light to interfere with each other, and
A control method of a photographing apparatus, characterized in that control is performed for changing a line width of the measurement light irradiating the measurement target by the irradiating unit for each of a plurality of photographing modes in which a photographing range of the measurement target is different. .

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