Optical tomography apparatus, optical tomography method, and program

Abstract

The present invention provides an optical tomography apparatus, an optical tomography method, and a program that can determine the location of acquisition of a tomographic image from an image captured of the surface of a target for measurement. [Solution] The optical tomography apparatus splits the light output from the light source into measurement light and reference light, irradiates the measurement object 11 while scanning with the measurement light, and generates a tomographic image based on the interference signal generated by the combination of the reflected light from the measurement object 11 and the reference light. The optical tomography apparatus includes a first mirror that reflects the reflected light of the measurement light from the deep part of the measurement object 11 in a first direction to be combined with the reference light, and also causes the measurement light to scan the measurement object 11 by rotating with a first axis r1 as the pivot axis, and an imaging unit 205 that images the surface of the measurement object using object light, which is visible light emitted from the surface of the measurement object 11. The first mirror 202 is fixed in a direction in which the object light is reflected towards the imaging unit 205 when the imaging unit 205 is in the imaging state.

Description

Technical Field

[0001] The present invention relates to an optical tomography imaging apparatus, an optical tomography imaging method, and a program.

Background Art

[0002] As an apparatus capable of capturing a tomographic image of a measurement object, an imaging apparatus using an optical coherence tomography (OCT) is known (for example, Patent Document 1). The optical tomography imaging apparatus described in Patent Document 1 repeatedly scans measurement light irradiated on the measurement object, and generates a tomographic image based on an interference signal between the reflected light and the reference light in the deep part of the measurement object. Based on the inclination of the measurement object with respect to the measurement light, it outputs a guide for inducing the operation of the probe held by the operator. Thereby, it is explained that the operability of the probe is improved.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the optical tomography imaging apparatus described in Patent Document 1, in order to capture a desired position in the measurement object, it is necessary to manually adjust the position of the probe according to the guide, and there is a problem that it is difficult to specify the measurement position when not used to it. Further, when the measurement object has a complicated shape, it is difficult to display an accurate guide, so the usage is limited.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical tomography imaging apparatus, an optical tomography imaging method, and a program capable of specifying the imaging position of a tomographic image based on an imaging image obtained by imaging the surface of a measurement object. [Means for solving the problem]

[0006] To achieve the above objective, the first embodiment of the optical tomography apparatus according to the present invention is an optical tomography apparatus that splits light output from a light source into measurement light and reference light, irradiates the object to be measured with the measurement light while scanning it, and generates a tomographic image based on an interference signal generated by the combination of the reflected light from the object to be measured and the reference light. The optical tomography apparatus comprises a first mirror that reflects the reflected light of the measurement light from the depths of the object to be measured in a first direction in which it is combined with the reference light, and also scans the object to be measured by rotating with a first axis as the pivot axis, and an imaging unit that images the surface of the object to be measured with object light, which is visible light emitted from the surface of the object to be measured. The first mirror is characterized in that, when the imaging unit is in the imaging state, it is fixed in a direction in which the object light is reflected in the direction of the imaging unit.

[0007] Furthermore, the optical tomography apparatus according to a second aspect of the present invention is characterized by comprising: a first mirror that reflects the reflected light of the measurement light at the depth of the object to be measured in a first direction to be combined with the reference light, and that scans the measurement light with respect to the object to be measured by rotation with the first axis as the pivot axis; an imaging unit that images the surface of the object to be measured using object light, which is visible light emitted from the surface of the object to be measured; and an optical filter provided between the first mirror and the object to be measured that reflects light in a predetermined wavelength band including the wavelength of the object light toward the imaging unit. [Effects of the Invention]

[0008] According to the present invention, the imaging unit images the surface of the object to be measured using object light reflected by the first mirror or optical filter, making it possible to determine the position of the tomographic image acquisition from the captured image of the surface of the object to be measured. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing an optical tomography apparatus according to Embodiment 1 of the present invention. [Figure 2]This figure shows the acquisition of a tomographic image using a scan probe according to Embodiment 1, with (a) being a perspective view and (b) being a schematic diagram. [Figure 3] This figure shows the surface of the scan probe according to Embodiment 1 during imaging, with (a) being a perspective view and (b) being a schematic diagram. [Figure 4] This is a block diagram of an optical tomography imaging apparatus according to Embodiment 1. [Figure 5] This is a flowchart of the optical tomography imaging process according to Embodiment 1. [Figure 6] This figure shows a scan probe according to Embodiment 2, with (a) being a perspective view and (b) being a schematic diagram. [Figure 7] This is a flowchart of the optical tomography imaging process according to Embodiment 2. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

[0011] The optical tomography apparatus 1 according to Embodiment 1 of the present invention is an imaging apparatus that captures a tomographic image of a measurement target 11, and is, for example, an apparatus that uses a time-domain optical coherence tomography (OCT) as shown in Figure 1. The measurement target 11 is any object such as the eyes, ears, internal organs or skin of a person or animal, a plant, a painted body of an automobile, a structure such as concrete, a precision part, or an electronic device. As shown in Figure 1, in the optical tomography apparatus 1, the light output from the light source 12 is split into measurement light and reference light by the beam splitter 13, and the measurement light is irradiated onto the measurement target 11 while scanning. The photosensor 14 receives light that is a composite of the reflected light from deep within the measurement target 11 and the reference light reflected by the reference mirror 15, and outputs an interference signal between the reflected light and the reference light. Note that Figure 1 is a schematic representation of the optical components and optical paths. In reality, for example, a 2x2 optical coupler is used as the beam splitter 13, and all or part of the optical paths between the light source 12 and the beam splitter 13, between the beam splitter 13 and the scan probe 20, between the beam splitter 13 and the reference mirror 15, and between the beam splitter 13 and the photosensor 14 are made of optical fiber.

[0012] The light source 12 is, for example, a Super Luminescent Diode (SLD) light source in the near-infrared region with a wavelength of 800 nm to 1600 nm, and the wavelength of the light output by the light source 12 varies depending on the measurement target or measurement conditions. For example, when the measurement target is the human eye, the wavelengths are in the 830 nm, 850 nm, and 1050 nm bands. In the case of OCT measurement of an endoscope or catheter, light at 1310 nm and 1325 nm is used. The photosensor 14 is any photoelectric conversion element such as a photodiode. The reference mirror 15 is a mirror that reflects the reference light. By moving the reference mirror 15 in parallel using a drive unit (not shown) and changing the distance from the beam splitter 13, the interference distance with the reflected light at the measurement target 11 changes. The peak position of the interference signal output by the photosensor 14 when the interference distance is changed can be detected as the boundary position between layers of the measurement target 11. That is, by moving the reference mirror 15, the measurement target 11 can be scanned in the depth direction. This depth-direction scanning is also called an A-scan.

[0013] The scan probe 20, inserted between the beam splitter 13 and the object to be measured 11, scans the measurement light in a direction perpendicular to the depth direction of the object to be measured 11. The configuration of the scan probe 20 according to this embodiment will be described in detail with reference to Figures 2 and 3. Figures 2(a) and 3(a) are perspective views illustrating the various components of the scan probe 20 arranged in three-dimensional space. Figures 2(b) and 3(b) are schematic diagrams illustrating the functions of each component of the scan probe 20 shown in Figures 2(a) and 3(a), respectively, and the arrangement of each component and the direction of light propagation are not necessarily limited thereto. As shown in Figures 2(a), (b) and 3(a), (b), the scan probe 20 includes a fiber collimator 201, a first mirror 202 and a second mirror 203 which are scan mirrors, an Fθ lens 204, and an imaging unit 205. The portion of the scan probe 20 that includes the first mirror 202 and the second mirror 203 functions as a reflector 220 that reflects the light reflected from deep within the object to be measured 11 and the visible light emitted from the surface of the object to be measured 11 in two different directions: a first direction p and a second direction q.

[0014] The fiber collimator 201 is an optical component that uses a lens to refract the measurement light, which is incident on the scan probe 20 through the optical fiber from the beam splitter 13, into parallel light and radiate it into space. The diameter of the parallel light radiated from the fiber collimator 201 is, for example, 3 to 4 mm. The second mirror 203 is a mirror that reflects the parallel measurement light in the direction of the first mirror 202. Furthermore, the second mirror 203 has a second axis r2 perpendicular to the direction of incidence of the light as its pivot axis, and the drive unit 208 rotates the second mirror 203 using the second axis r2 as its pivot axis. By rotating the second mirror 203 by the drive unit 208, the reflection direction of the measurement light can be changed and scanned against the measurement target 11. For example, the reflective surface of the second mirror 203 is repeatedly rotated back and forth with an angular width of 10 to 20 degrees, with a center angle of 45 degrees with respect to the optical axis of the fiber collimator 201, thereby changing the reflection direction of the measurement light. Scanning by rotating the second mirror 203 is sometimes called a B scan.

[0015] The first mirror 202 is a mirror that reflects the measurement light reflected by the second mirror 203 in the direction of the object to be measured 11. Furthermore, the first mirror 202 has a first axis r1 that is perpendicular to the direction of incidence of the light as its pivot axis, and the drive unit 209 rotates the first mirror 202 using the first axis r1 as its pivot axis. By rotating the first mirror 202 by the drive unit 209, the reflection direction of the measurement light can be changed and scanned relative to the object to be measured 11. More specifically, the reflective surface of the first mirror 202 is repeatedly rotated back and forth within an angular range of 10 to 20 degrees, with a center angle of 45 degrees with respect to the optical axis of the Fθ lens 204, thereby changing the reflection direction of the measurement light. Scanning by the rotation of the first mirror 202 is sometimes called a C scan. As shown in Figure 2(a), the second axis r2, which is the pivot axis of the second mirror 203, is perpendicular to the axis obtained by translating the first axis r1, which is the pivot axis of the first mirror 202. Therefore, the B scan by the second mirror 203 and the C scan by the first mirror 202 are scans in mutually orthogonal directions.

[0016] Furthermore, the first mirror 202 reflects the light reflected from deep within the measurement target 11, which is illuminated while scanning, in the direction of the second mirror 203 (first direction p). The reflected light is further reflected by the second mirror 203 and incident on the fiber collimator 201. The interference signal between the reflected light that has passed through the fiber collimator 201 and the reference light is detected by the photosensor 14. In other words, the optical path of the reflected light from the deep within the measurement target 11 until it is combined with the reference light is the same optical path as the optical path of the measurement light heading towards the measurement target 11. Strictly speaking, slight differences may occur in these optical paths due to the scanning of the measurement light, but these optical paths are substantially identical. Also, the second mirror 203 is located on the optical path from when the reflected light is reflected by the first mirror 202 until it is combined with the reference light. As shown in Figures 1 and 2(a) and (b), the optical tomography apparatus 1 can obtain the three-dimensional shape of the interlayer boundaries of the measurement target 11 based on the interference signal between the reflected light at the depth of the measurement target 11 and the reference light when performing B scans and C scans in a planar direction perpendicular to the depth direction by translating the reference mirror 15.

[0017] As shown in Figures 3(a) and 3(b), the first mirror 202 can be rotated further to orient its reflective surface toward the imaging unit 205. More specifically, when the imaging unit 205 is in the imaging state, the orientation of the reflective surface of the first mirror 202 is fixed so that the object light, which is visible light emitted from the surface of the object to be measured 11, is reflected by the first mirror 202 in the second direction q and incident upon the imaging unit 205. For example, the reflective surface of the first mirror 202 is oriented in a direction inclined at 45 degrees with respect to the optical axis of the reflected measurement light and the center line of the imaging unit 205. The rotation angle of the first mirror 202 from the state in which the measurement light is scanned as shown in Figure 2(a) to the state in which the object light is incident upon the imaging unit 205 as shown in Figure 3(a) is, for example, 90 degrees. In other words, the 180-degree change in direction from the first direction p, from the first mirror 202 to the second mirror 203 as shown in Figure 2(a), to the second direction q, from the first mirror 202 to the imaging unit 205 as shown in Figure 3(a), is achieved by a 90-degree rotation of the first mirror 202.

[0018] The Fθ lens 204 is a lens that condenses the light in the area scanned by B-scan and C-scan into light with a spot diameter equal to or less than a predetermined value. The imaging unit 205 is an element that images the surface of the measurement object 11 with object light, which is visible light radiated from the surface of the measurement object 11 and reflected by the first mirror 202, and is, for example, a camera. The irradiation unit 206 is a light source that irradiates the measurement object 11 with visible light when the imaging unit 205 images the surface of the measurement object 11 as shown in FIGS. 3(a) and (b). The wavelength of the visible light radiated by the irradiation unit 206 is, for example, 300 - 700 nm. Note that the imaging unit 205 may image with object light in a natural light environment. The surface of the measurement object 11 needs to be a material that reflects the light of the irradiation unit 206 or natural light.

[0019] The optical tomography imaging apparatus 1 further includes a control unit 10 that controls each of the above-described components, and a monitor 210 that displays the tomographic image and the surface image of the measurement object 11. As shown in FIG. 4, the control unit 10 includes a processor 100 and a storage unit 200. The processor 100 is configured by, for example, a CPU or the like, and executes various processes according to a program stored in the storage unit 200. The storage unit 200 includes, for example, a RAM, and a nonvolatile memory such as a ROM and a flash memory. The RAM functions as a working memory of the processor 100, and temporarily stores a program read from the nonvolatile memory, and data created or changed during program execution. The nonvolatile memory stores a program executed by the CPU of the processor 100 and data necessary in advance for executing the program.

[0020] By executing the optical tomography imaging processing program stored in the storage unit 200, the processor 100 functions as an imaging control unit 101, an optical tomography imaging unit 102, and a mode switching unit 103. The imaging control unit 101 rotates the first mirror 202 by driving the drive unit 209, and as shown in Fig. 3(a), the object light radiated from the surface of the measurement object 11 is reflected by the first mirror 202 and the reflecting surface faces the direction of incidence to the imaging unit 205. Further, the imaging control unit 101 lights the irradiation unit 206 and displays the image captured by the imaging unit 205 on the monitor 210. Here, the drive unit 209 that drives the first mirror 202 and the irradiation unit 206 may be interlocked. That is, the irradiation unit 206 may be lit when the first mirror 202 is in the direction of reflecting the object light toward the imaging unit 205, and the irradiation unit 206 may be turned off when the first mirror 202 is in the direction of reflecting the reflected light for combining with the reference light.

[0021] The optical tomography imaging unit 102 rotates the first mirror 202 by driving the drive unit 209, and as shown in Fig. 2(a), the reflecting surface of the first mirror 202 faces the direction in which the reflected light of the measurement light reflected in the depth of the measurement object 11 is reflected by the first mirror 202 and enters the second mirror 203. The optical tomography imaging unit 102 outputs the measurement light to the light source 12, and repeatedly drives the drive units 208, 209 and the drive unit of the reference mirror 15 back and forth to scan the measurement light with respect to the measurement object 11. The optical tomography imaging unit 102 further obtains a detection signal when the reflected light is reflected by the first mirror 202 and the second mirror 203 and enters the photosensor 14 through the fiber collimator 201, and generates a tomographic image based on the detection signal. The generated tomographic image is displayed on the monitor 210.

[0022] The mode switching unit 103 switches between a first mode for displaying the captured image of the surface of the measurement object 11 on the monitor 210 and a second mode for displaying the tomographic image of the measurement object 11 on the monitor 210, either by a user operation or automatically. That is, the mode switching unit 103 switches between a first mode in which the imaging control unit 101 is operated and a second mode in which the optical tomography imaging unit 102 is operated.

[0023] The operation of the optical tomography imaging apparatus 1 described above will now be explained in accordance with the flowchart in Figure 5. The scan probe 20 is placed near the measurement position of the measurement target 11, and the optical tomography imaging process is performed. First, the mode switching unit 103 switches to the first mode, which activates the imaging control unit 101 and rotates the first mirror 202 (step S101). Specifically, the imaging control unit 101 rotates the first mirror 202 by driving the drive unit 209, fixing the direction of the reflective surface of the first mirror 202 so that object light emitted from the surface of the measurement target 11 is reflected by the first mirror 202 in the second direction q and incident on the imaging unit 205, as shown in Figure 3(a). After that, the imaging control unit 101 turns on the illumination unit 206 to irradiate the measurement target 11 with visible light, and the imaging unit 205 enters an imaging state in which it images the surface of the measurement target 11 with object light, which is visible light emitted from the surface of the measurement target 11 (step S102). The image captured by the imaging unit 205 is displayed on the monitor 210. Based on the image displayed on the monitor 210, the user adjusts the position of the scan probe 20 relative to the measurement target 11. At this time, either the measurement target 11 or the scan probe 20 may be moved. Based on the image displayed on the monitor 210, the user determines the position for acquiring the tomographic image, aligns the scan probe 20 relative to the measurement target 11 so that this position is in the center of the Fθ lens 204, and fixes the position of the scan probe 20 relative to the measurement target 11. After that, the irradiation unit 206 is turned OFF (step S103).

[0024] Next, the mode switching unit 103 switches to the second mode for performing OCT measurement, thereby activating the optical tomography unit 102 and rotating the first mirror 202 (step S104). Specifically, the optical tomography unit 102 rotates the first mirror 202 by driving the drive unit 209, and sets the direction of the reflective surface of the first mirror 202 so that the reflected light of the measurement light reflected from the depths of the measurement target 11 is reflected by the first mirror 202 in a first direction p and incident on the second mirror 203, as shown in Figure 2(a). The optical tomography unit 102 turns on the light source 12 and irradiates the measurement light onto the measurement target 11, while moving the reference mirror 15 back and forth by driving the drive unit of the reference mirror 15, and also repeatedly rotates the first mirror 202 and the second mirror 203 back and forth by driving the drive units 209 and 208. In this way, the optical tomography unit 102 scans the measurement light with respect to the measurement target 11. The optical tomography unit 102 acquires a detection signal when reflected light is reflected by the first mirror 202 and the second mirror 203 and incident on the photosensor 14, and generates a tomographic image based on the detection signal (step S105). The optical tomography unit 102 displays the generated tomographic image on the monitor 210 and terminates the process. This makes it possible to position the system based on the image captured by the imaging unit 205 and then capture a tomographic image at the desired position.

[0025] As described above, the optical tomography apparatus 1 according to Embodiment 1 splits the light output from the light source into measurement light and reference light, irradiates the measurement target 11 while scanning with the measurement light, and generates a tomographic image based on an interference signal generated by combining the reflected light from the measurement target 11 and the reference light. The scan probe 20 of the optical tomography apparatus 1 includes a first mirror 202 that reflects the reflected light from the deep part of the measurement target 11 of the measurement light in a first direction to be combined with the reference light, and scans the measurement light with respect to the measurement target 11 by rotating with a first axis r1 as the pivot axis, and an imaging unit 205 that images the surface of the measurement target 11 with object light, which is visible light emitted from the surface of the measurement target 11. The first mirror 202 of the scan probe 20 is fixed in a direction in which the object light is reflected towards the imaging unit 205 when the imaging unit 205 is in the imaging state. This makes it possible to identify the acquisition position of the tomographic image by the image taken of the surface of the measurement target 11.

[0026] The optical tomography apparatus 1 according to Embodiment 2 of the present invention differs from Embodiment 1 in the configuration of the reflective section 230 of the scan probe 40. The other configurations are the same as in Embodiment 1. This will be explained in detail with reference to Figures 6(a) and (b). The scan probe 40 of the optical tomography apparatus 1 according to this embodiment includes a fiber collimator 201 similar to that of Embodiment 1, a first mirror 202 and a second mirror 203 which are scan mirrors, an Fθ lens 204, and an imaging unit 205. The scan probe 40 further includes an optical filter 207 provided between the first mirror 202 and the Fθ lens 204.

[0027] The optical filter 207 has the function of transmitting the light reflected from deep within the object being measured 11 toward the first mirror 202, and reflecting the object light emitted from the surface of the object being measured 11 toward the imaging unit 205 in a second direction q. Specifically, the optical filter 207 is an optical filter that transmits light in a wavelength band including near-infrared light output by the light source 12, and reflects light in a predetermined range of wavelength bands including the wavelength of the object light. The portion of the scan probe 40 that includes the first mirror 202, the second mirror 203, and the optical filter 207 functions as a reflecting unit 230 that reflects the light reflected from deep within the object being measured 11 and the object light emitted from the surface of the object being measured 11 toward two different directions, a first direction p and a second direction q.

[0028] The configuration and function of the fiber collimator 201 and the second mirror 203 are the same as in Embodiment 1. The first mirror 202, as in Embodiment 1, is a mirror that reflects the measurement light reflected by the second mirror 203 towards the object to be measured 11, and reflects the reflected light from deep within the object to be measured 11 back towards the second mirror 203 in a first direction p. The first mirror 202 has a first axis r1 perpendicular to the direction of incidence of the light as its pivot axis, and the drive unit 209 rotates the first mirror 202 using the first axis r1 as its pivot axis. By rotating the first mirror 202 by the drive unit 209, the reflection direction of the measurement light can be changed and scanned relative to the object to be measured 11. More specifically, the reflective surface of the first mirror 202 is repeatedly reciprocated within an angular range of 10 to 20 degrees, with a center angle of 45 degrees with respect to the optical axis of the Fθ lens 204, thereby changing the reflection direction of the measurement light. That is, a C scan is performed by rotating the first mirror 202. The first mirror 202 only repeatedly rotates back and forth within the angle range of 10 to 20 degrees as described above, and differs from Embodiment 1 in that its reflective surface is not oriented toward the imaging unit 205. In this embodiment as well, by performing an A scan in the depth direction by translating the reference mirror 15, and performing B scans and C scans in a planar direction perpendicular to the depth direction, the three-dimensional shape of the boundary between layers of the object to be measured 11 can be obtained.

[0029] When the optical tomography unit 102 captures a tomographic image, the optical filter 207 transmits the measurement light in the near-infrared wavelength band emitted by the light source 12 and the reflected light reflected by the object to be measured 11. The transmitted reflected light is reflected by the first mirror 202 and the second mirror 203 and incident on the photosensor 14. When the imaging control unit 101 images the surface of the object to be measured 11, the optical filter 207 reflects the visible light emitted from the surface of the object to be measured 11 toward the imaging unit 205. Therefore, the surface of the object to be measured 11 can be imaged without rotating the first mirror 202 by approximately 90 degrees.

[0030] The operation of the optical tomography imaging device 1 described above will now be explained in accordance with the flowchart in Figure 7. First, the imaging control unit 101 is activated by setting the mode switching unit 103 to the first mode (step S201). Specifically, the imaging control unit 101 turns on the illumination unit 206 to irradiate the measurement target 11 with visible light, and the imaging unit 205 images the surface of the measurement target 11 using the object light, which is visible light emitted from the surface of the measurement target 11 (step S202). The image captured by the imaging unit 205 is displayed on the monitor 210. Based on the image displayed on the monitor 210, the user adjusts the position of the scan probe 40 relative to the measurement target 11. At this time, either the measurement target 11 or the scan probe 40 may be moved. Based on the image displayed on the monitor 210, the user determines the position for capturing the tomographic image and fixes the position of the scan probe 40 relative to the measurement target 11 by aligning it so that this position is in the center of the Fθ lens 204. After that, the illumination unit 206 is turned OFF (step S203).

[0031] Next, the mode switching unit 103 switches to the second mode, activating the optical tomography unit 102 and rotating the first mirror 202 (step S204). Specifically, the optical tomography unit 102 turns on the light source 12 and irradiates the measurement object 11 with measurement light, while the reference mirror 15 is moved back and forth by the drive unit of the reference mirror 15, and the first mirror 202 and the second mirror 203 are repeatedly rotated back and forth by the drive units 208 and 209. As a result, the optical tomography unit 102 scans the measurement light with respect to the measurement object 11. The optical tomography unit 102 acquires a detection signal when the reflected light is reflected by the first mirror 202 and the second mirror 203 and incident on the photosensor 14, and generates a tomographic image based on the detection signal (step S205). The optical tomography unit 102 displays the generated tomographic image on the monitor 210 and terminates the process. This allows for positioning based on the image captured by the imaging unit 205, and then capturing a tomographic image at the desired position.

[0032] As described above, in the optical tomography apparatus 1 according to Embodiment 2, an optical filter 207 is provided between the first mirror 202 of the scan probe 40 and the object to be measured 11, and reflects light in a predetermined wavelength band including the wavelength of the object light, thereby reflecting the object light toward the imaging unit 205. This makes it possible to determine the position of the tomography image acquisition by the image captured of the surface of the object to be measured 11 without having to rotate the first mirror 202 significantly.

[0033] Although embodiments of the present invention have been described above, these embodiments are merely examples, and the scope of application of the present invention is not limited thereto. That is, the embodiments of the present invention can be applied in various ways, and all embodiments are included within the scope of the present invention. For example, in embodiments 1 and 2, the case in which the scan probes 20 and 40 are used in a time-domain optical tomography (OCT) system has been described, but the invention is not limited thereto. The scan probe 20 can be used in any other optical tomography imaging device, such as a Fourier-domain optical tomography system.

[0034] Furthermore, in Embodiment 1, a first mirror 202 was used as the reflecting section 220, 230 that reflects the reflected light from deep within the object being measured 11 and the object light emitted from the surface of the object being measured 11, respectively. In Embodiment 2, a first mirror 202 and an optical filter 207 were used. However, the configuration of the reflecting section 220, 230 may be other configurations. For example, if the spot diameter of the reflected light from the object being measured 11 is sufficiently smaller than the luminous flux of the object light, a third mirror sufficiently larger than the first mirror 202, with a rotatable first mirror 202 in the center, may be used to reflect the object light.

[0035] Furthermore, in the embodiments 1 and 2 described above, the program executed by the processor 100 is pre-stored in the non-volatile memory of the storage unit 200. However, the present invention is not limited thereto, and the program for executing the above-described optical tomography imaging process may be implemented in an existing general-purpose computer or the like, thereby functioning as a device equivalent to the control unit 10 of the optical tomography imaging apparatus 1 according to embodiments 1 and 2 described above.

[0036] The method of providing such programs is optional. For example, they may be distributed by storing them on a computer-readable storage medium (flexible disk, CD (Compact Disc)-ROM, DVD (Digital Versatile Disc)-ROM, MO (Magneto Optical Disc), memory card, USB memory, etc.), or they may be stored on network storage such as the internet and provided for download.

[0037] Furthermore, when the above-mentioned processing is performed through a division of labor between the OS (Operating System) and the application program, or through collaboration between the OS and the application program, only the application program may be stored on a recording medium or storage device. It is also possible to superimpose the program onto a carrier wave and distribute it over a network. For example, the above program may be posted on a bulletin board system (BBS) on a network and distributed over the network. This program can then be launched and executed under the control of the OS, just like other application programs, to perform the above-mentioned processing.

[0038] Furthermore, the control unit 10 may consist of any single processor, such as a single processor, multi-processor, or multi-core processor, or it may be configured by combining any of these processors with processing circuits such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array).

[0039] This invention allows for various embodiments and modifications without departing from the broad spirit and scope of the invention. Furthermore, the embodiments described above are for illustrative purposes only and do not limit the scope of the invention. In other words, the scope of the invention is indicated not by the embodiments, but by the claims. Various modifications made within the scope of the claims and the equivalent scope of the meaning of the invention are considered to be within the scope of the invention. [Explanation of Symbols]

[0040] 1... Optical tomography device, 11... Measurement target, 202... First mirror, 205... Imaging unit, 207... Optical filter, 209... Drive unit, r1... First axis

Claims

1. An optical tomography apparatus that splits light output from a light source into a measurement light and a reference light, irradiates the object to be measured with the measurement light while scanning, and generates a tomographic image based on an interference signal generated by the combination of the reflected light from the object to be measured and the reference light, A first mirror that reflects the reflected light of the measurement light at the depth of the object to be measured in a first direction to be combined with the reference light, and scans the measurement light with respect to the object to be measured by rotation with the first axis as the pivot axis, The system includes an imaging unit that images the surface of the object to be measured using object light, which is visible light emitted from the surface of the object to be measured, The first mirror is fixed in such a orientation that, when the imaging unit is in the imaging state, the object light is reflected in the direction of the imaging unit. Optical tomography equipment.

2. An optical tomography apparatus that splits light output from a light source into a measurement light and a reference light, irradiates the object to be measured with the measurement light while scanning, and generates a tomographic image based on an interference signal generated by the combination of the reflected light from the object to be measured and the reference light, A first mirror that reflects the reflected light of the measurement light at the depth of the object to be measured in a first direction to be combined with the reference light, and scans the measurement light with respect to the object to be measured by rotation with the first axis as the pivot axis, An imaging unit that images the surface of the object to be measured using object light, which is visible light emitted from the surface of the object to be measured, The system includes an optical filter provided between the first mirror and the object to be measured, which reflects light in a predetermined wavelength band including the wavelength of the object light toward the imaging unit, Optical tomography equipment.

3. The optical path of the reflected light from the object to be measured to its combination with the reference light is the same optical path as the optical path of the measurement light toward the object to be measured. The optical tomography apparatus according to claim 1 or 2.

4. A second mirror is further provided in the optical path from when the reflected light is reflected by the first mirror and combined with the reference light. The second mirror has a second axis as its pivot axis that is perpendicular to the axis parallel to the first axis, which is the pivot axis of the first mirror. The optical tomography apparatus according to claim 1 or 2.

5. The system further includes an illumination unit that irradiates the object to be measured with visible light when imaging is performed by the imaging unit, and turns off when the tomographic image is generated. The optical tomography apparatus according to claim 1 or 2.

6. The system further includes an illumination unit that irradiates the object to be measured with visible light when imaging is performed by the imaging unit, The first mirror and the illumination unit are linked, and the illumination unit is turned on when the first mirror is oriented to reflect the object light toward the imaging unit, and the illumination unit is turned off when the first mirror is oriented to reflect the reflected light toward the reference light. The optical tomography apparatus according to claim 1.

7. The system further includes a control unit that can select and execute a first mode, which displays a tomographic image of the object to be measured based on the interference signal between the reflected light and the reference light when the irradiation unit is turned off and the measurement light is irradiated onto the object to be measured while scanning it, and a second mode, which displays an image of the surface of the object to be measured captured by the imaging unit when the irradiation unit is turned on. The optical tomography apparatus according to claim 5.

8. A method for optical tomography, comprising: splitting light output from a light source into a measurement light and a reference light; irradiating the object to be measured with the measurement light while scanning it; and generating a tomographic image based on an interference signal generated by combining the reflected light from the object to be measured with the reference light, A first mirror, which rotates with the first axis as the pivot axis, is fixed in a direction such that object light, which is visible light emitted from the surface of the object to be measured, is reflected towards the imaging unit, and the imaging unit is made to image the surface of the object to be measured. The first mirror reflects the reflected light of the measurement light at the depth of the object to be measured in a first direction to be combined with the reference light, and the rotation of the first mirror scans the measurement light with respect to the object to be measured, thereby generating the tomographic image based on the interference signal between the reflected light and the reference light. Optical tomography imaging method.

9. A method for optical tomography, comprising: splitting light output from a light source into a measurement light and a reference light; irradiating the object to be measured with the measurement light while scanning it; and generating a tomographic image based on an interference signal generated by combining the reflected light from the object to be measured with the reference light, A first mirror, which rotates on a first axis as its pivot point, and the object to be measured are connected by an optical filter that reflects light in a predetermined wavelength band including the wavelength of object light, which is visible light emitted from the surface of the object to be measured. This optical filter reflects the object light towards the imaging unit, causing the imaging unit to image the surface of the object to be measured. The reflected light of the measurement light at the depth of the object to be measured is transmitted through the optical filter and reflected in a first direction by the first mirror to be combined with the reference light, and the measurement light is scanned with respect to the object to be measured by rotating the first mirror, and the tomographic image is generated based on the interference signal between the reflected light and the reference light. Optical tomography imaging method.

10. A computer controls an optical tomography apparatus that splits light output from a light source into measurement light and reference light, irradiates the object to be measured with the measurement light while scanning, and generates a tomographic image based on an interference signal generated by the combination of the reflected light from the object to be measured and the reference light. A first mirror, which is rotatable with respect to a first axis, is fixed in a direction such that object light, which is visible light emitted from the surface of the object to be measured, is reflected in the direction of the imaging unit, and an imaging control unit displays the image of the surface of the object to be measured captured by the imaging unit on a monitor. The optical tomography unit uses the first mirror to reflect the reflected light of the measurement light at the depth of the object to be measured in a first direction to be combined with the reference light, and rotates the first mirror to scan the measurement light with respect to the object to be measured, and displays a tomographic image generated based on the interference signal between the reflected light and the reference light on the monitor. A program designed to function as such.

11. A computer controls an optical tomography apparatus that splits light output from a light source into measurement light and reference light, irradiates the object to be measured with the measurement light while scanning, and generates a tomographic image based on an interference signal generated by the combination of the reflected light from the object to be measured and the reference light. An imaging control unit is provided between a first mirror that rotates on a first axis and the object to be measured, and an optical filter that reflects light in a predetermined wavelength band including the wavelength of object light, which is visible light emitted from the surface of the object to be measured, so that the object light is reflected in the direction of the imaging unit and the image of the surface of the object to be measured captured by the imaging unit is displayed on a monitor. An optical tomography unit that reflects the reflected light of the measurement light at the depth of the object to be measured through the optical filter and is reflected in a first direction by the first mirror so as to be combined with the reference light, and scans the measurement light with respect to the object to be measured by rotating the first mirror, and displays a tomographic image generated based on the interference signal between the reflected light and the reference light on the monitor. A program designed to function as such.

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