JP2016067588A - Optical coherence tomographic apparatus and control method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical coherence tomographic apparatus which can shorten scanning time and whose cost can be suppressed.SOLUTION: An optical coherence tomographic apparatus comprises: a data acquisition unit having scanning means capable of performing scanning with measurement light in a first scanning pattern and a second scanning pattern different from the first scanning pattern on an inspection object; a coherence optical system for generating a coherence signal based on coherence light obtained by allowing the measurement light through the inspection object and reference light corresponding to the measurement light to interfere with each other; and tomographic image generation means for generating a tomographic image of the inspection object on the basis of the coherence signal. In the optical coherence tomographic apparatus, plane image generation means for generating a plane image of the inspection object on the basis of the coherence signal, and control means for changing at least one of the first scanning pattern and the second scanning pattern, are arranged.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an optical coherence tomography apparatus for obtaining a tomographic image of an object to be inspected, and a control method for the optical coherence tomography apparatus.

  Currently, various devices are used as devices for inspecting an object using an optical device, for example, ophthalmic devices having an eye as an object to be inspected.

  Examples of the ophthalmologic apparatus for observing the eye include various apparatuses such as a fundus camera and a confocal laser scanning ophthalmoscope (SLO). Among them, an optical coherence tomography (OCT) is an apparatus that takes a tomographic image of an eye to be examined with high resolution, and is becoming an indispensable apparatus for diagnosis of retinal diseases as an ophthalmic apparatus.

  The SLO apparatus can obtain an SLO image that is a planar image of the anterior eye portion of the eye to be examined and the fundus oculi portion of the eye to be examined with high contrast by using a laser of infrared light by a confocal method.

  The OCT apparatus irradiates the eye to be examined with low coherent light, and obtains luminance information in the depth direction of the retina, for example, using an interference system that combines the reflected light from the eye to be examined with the reference light. It is an apparatus which acquires the tomographic image of this. In the OCT apparatus, tomographic images in the scanning range can be taken by scanning low-coherent light on the fundus of the eye to be examined. Therefore, it is widely used in diagnosis of a desired area in the retina.

  The OCT apparatus can not only obtain a tomographic image of the eye to be examined but also generate an anterior ocular segment observation image of the eye to be examined and a fundus image of the eye to be examined from a plurality of tomographic data of the eye to be examined.

  For example, Patent Document 1 discloses an OCT apparatus capable of generating a fundus image of an eye to be examined. In this apparatus, using data that forms a tomographic image obtained by scanning a two-dimensional region, an integrated image in the depth direction of a three-dimensional tomographic image, an integrated value of spectrum data at each XY position, Information such as luminance data and retinal surface layer images at XY positions in a certain depth direction is obtained. And it is supposed that the fundus image of the eye to be examined can be generated from these information.

  In addition, there is known an apparatus capable of obtaining a tomographic image of the eye to be examined and a fundus image of the eye to be examined by combining the above-described OCT optical system with the SLO optical system.

JP 2012-161426 A

  In diagnosing the eye, it is preferable to obtain both of these images at the same time in order to confirm the portion of the fundus image from which the retinal tomographic image is obtained. In this case, an ophthalmic apparatus in which the SCT optical system is combined with the OCT optical system as described above is used. In the ophthalmologic apparatus, the scanning time can be shortened by using an OCT optical system for acquiring a tomographic image and using an SLO optical system for acquiring a fundus image. However, in order to actually construct the device, there is a problem that the device becomes larger and the cost becomes higher.

  Further, as exemplified in Patent Document 1, it is also possible to acquire a fundus image using an OCT optical system without using an SLO optical system. However, in this case, since it is necessary to scan the fundus of the eye to be examined in order to obtain the fundus image of the eye to be examined, there is a problem that it takes time to scan compared to an apparatus using an OCT optical system and an SLO optical system. It was.

  In view of the above-described problems, an object of the present invention is to provide an optical coherence tomography apparatus that shortens the scanning time and suppresses the cost of the apparatus.

  In order to achieve the above object, an optical coherence tomography apparatus according to the present invention comprises the following arrangement.

That is, a data acquisition unit having a scanning unit capable of scanning measurement light with a first scanning pattern and a second scanning pattern different from the first scanning pattern on the inspection object;
An interference optical system that generates an interference signal based on interference light obtained by causing interference between the measurement light through the inspection object and reference light corresponding to the measurement light;
A tomographic image generating means for generating a tomographic image of the object to be inspected based on an interference signal by the first scanning pattern;
A plane image generating means for generating a plane image of the object to be inspected based on an interference signal by the second scanning pattern;
Control means for changing at least one of the first scanning pattern and the second scanning pattern.

  According to the present invention, it is possible to provide an optical coherence tomography apparatus that can shorten the scanning time and further reduce the cost of the apparatus.

It is a block diagram of the optical coherence tomography apparatus which concerns on one Embodiment of this invention. It is a schematic diagram which shows the structure of the data acquisition part in the optical coherence tomography apparatus shown in FIG. It is a schematic diagram which shows the structure of the image process part and display part in the optical coherence tomography apparatus shown in FIG. It is a figure which shows an example of the display screen of the display part shown in FIG. It is a figure which illustrates the brightness | luminance information obtained as an A scan image. FIG. 6 is a diagram illustrating a manner of rearrangement of luminance information illustrated in FIG. 5. It is a figure which illustrates the anterior eye part observation image and plane image which are displayed on a display part at the time of observation. It is a figure which shows the positional relationship of the whole fundus image and a planar image area. It is a figure which shows typically the mode of the OCT scanning in a plane image area.

  Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a configuration diagram of an optical coherence tomography apparatus according to the present embodiment.

  The optical coherence tomography apparatus according to this embodiment includes a data acquisition unit 100, an image processing unit 101, and a display unit 102. The data acquisition unit 100 acquires image data by scanning and photographing the measurement light on the eye to be examined. The image processing unit 101 constructs a tomographic image of the eye to be examined from the image data acquired by the data acquisition unit 100. The display unit 102 displays a tomographic image of the eye to be examined, which is configured by the data acquisition unit 100 and the image processing unit 101.

  First, the configuration of the data acquisition unit 100 will be described.

  FIG. 2 schematically shows the configuration of the data acquisition unit 100 according to an embodiment of the present invention. The objective lens 1 is installed facing the eye to be examined Er, and the first dichroic mirror 2 and the second dichroic mirror 3 are arranged on the optical axis. The optical path passing through the objective lens 1 from the eye to be examined Er is, by these dichroic mirrors, the optical path L1 of the OCT optical system, the light path L2 for fixation light for promoting fixation of the eye to be examined Er, and for anterior eye portion observation. Branches to the optical path L3 for each wavelength band.

  On the optical path L2 for the fixation lamp, the focus lens 4, the lens 5, and the fixation lamp 6 are arranged in this order from the eye to be examined Er side. The focus lens 4 is driven by a motor (not shown) in order to focus the fixation target presented by the fixation lamp 6 on the eye to be examined Er. The fixation lamp 6 generates visible light and promotes fixation of the subject. Further, the fixation lamp 6 can be blinked, and a fixation target is presented by creating an arbitrary shape at an arbitrary position on the eye Er, and prompts the subject to fixate.

  On the optical path L3 for observing the anterior eye part, the lens 7, the split prism 8, the lens 9, and the CCD 10 for observing the anterior eye part are arranged in this order from the eye side to be examined Er. The CCD 10 has sensitivity at a wavelength of a light source for anterior ocular segment observation (not shown), specifically, around 970 nm.

  The split prism 8 is arranged at a position conjugate with the pupil of the eye to be examined Er, and forms a split image of the anterior segment on the CCD 10. The split image provides information corresponding to the distance between the eye to be examined Er and the data acquisition unit 100 in the Z direction (front-rear direction). Therefore, the distance relationship between the eye to be examined Er and the data acquisition unit 100 can be grasped by detecting the split image.

  On the optical path L1 of the OCT optical system for taking image data of the eye to be examined Er, the XY scanner 11, the focus lens 12, and the lens 13 are arranged in this order from the eye to be examined Er side. The XY scanner 11 serves as OCT scanning means for scanning the measurement light from the OCT light source 14 on the eye to be examined. As will be described later, the XY scanner 11 scans the measuring light with the first scanning pattern and the second scanning pattern different from the first scanning pattern on the eye Er, that is, the inspection object. Corresponds to the means. In FIG. 2, the XY scanner 11 is shown as a single mirror, but actually comprises a pair of galvanometer mirrors that perform scanning in the XY biaxial directions. In this embodiment, an example in which a pair of galvanometer mirrors is used as the OCT scanning unit has been described. However, various known scanners such as a resonance scanner may be used according to measurement conditions such as a measurement speed.

  The focus lens 12 is for focusing measurement light from an OCT light source 14 emitted from a fiber 15 described later on the eye to be examined Er, and is driven in the optical axis direction by a motor (not shown). By this focusing, the return light from the eye to be examined Er is simultaneously imaged in the form of a spot on the tip of the fiber 15 and is incident on the fiber 15.

  The OCT optical system further includes an optical coupler 19, an OCT light source 14, optical fibers 15 to 18 connected to the optical coupler 19, a lens 20, a dispersion compensation glass 21, a reference mirror 22, and a spectroscope 23. doing.

  The light emitted from the OCT light source 14 via the optical fiber 16 is divided into measurement light and reference light by an optical coupler 19. The measurement light passes through the optical fiber 15 to the optical path L1 of the OCT optical system, and is emitted from the exit end of the optical fiber 15 along the optical path L1. The measurement light that has passed through the optical path L1 is reflected by the second dichroic mirror 3, and is emitted toward the eye to be examined Er located outside the data acquisition unit 100 via the objective lens 1. The measurement light emitted toward the eye to be examined Er is reflected and scattered by the eye to be examined Er and passes the same path in the reverse direction to reach the exit end of the optical coupler 15.

  On the other hand, the reference light is emitted from the emission end portion thereof toward the lens 20 through the optical fiber 17. After passing through the lens 20, the reference light reaches the reference mirror 22 through the dispersion compensation glass 21 and is reflected. The reference light reflected from the reference mirror 22 reaches the exit end of the optical fiber 17 through the same optical path in the reverse direction. The configuration for driving the optical fiber 17, the lens 20, the dispersion compensation glass 21, the reference mirror 22, and the reference mirror 22 changes the optical path length of the reference light so that the reference light corresponds to the measurement light via the eye to be examined Er. A reference optical system is configured.

  Thus, the measurement light reaching the optical fiber 15 and the reference light reaching the optical fiber 17 are combined by an optical coupler 19 to which these fibers are connected to become interference light. The optical coupler 19 constitutes a light beam splitting unit that splits the light beam emitted from the light source into measurement light and reference light. Here, interference occurs when the optical path length of the measurement light and the optical path length of the reference light are substantially the same. The reference mirror 22 is held so as to be adjustable in the optical axis direction by a motor and a driving mechanism (not shown), and the optical path length of the reference light can be adjusted to the optical path length of the measurement light that changes depending on the eye to be examined Er. The interference light is guided to the spectroscope 23 through the optical fiber 18 connected to the optical coupler 19.

  The spectroscope 23 includes lenses 24 and 26, a diffraction grating 25, and a line sensor 27. The interference light emitted from the optical fiber 18 becomes parallel light through the lens 24, and then is split by the diffraction grating 25 and imaged on the line sensor 27 by the lens 26. These constitute an interference optical system that generates an interference signal based on interference light obtained by causing interference between the measurement light passing through the eye to be examined and the reference light corresponding to the measurement light.

  In the present embodiment, the Michelson interference system is used as the interference system, but a Mach-Zehnder interference system may be used. It is desirable to use a Mach-Zehnder interference system when the light amount difference is large and a Michelson interference system when the light amount difference is relatively small, depending on the light amount difference between the measurement light and the reference light.

  Next, configurations of the image processing unit 101 and the display unit 102 will be described.

  FIG. 3 is a schematic diagram illustrating the configuration of the image processing unit 101 and the display unit 102. The image processing unit 101 includes an image generation unit 31 and a storage unit 32. The image generation unit 31 is connected to the line sensor 27 of the data acquisition unit 100 and the storage unit 32 in the image processing unit 101. The image generation unit 31 is also connected to the XY scanner 11 and scans the measurement light in the X direction and the Y direction on the eye to be examined Er using the XY scanner 11. Then, a planar image is generated from a plurality of data obtained from the line sensor 27 when the measurement light is scanned, that is, from a plurality of tomographic image data. A method for generating a planar image from a plurality of tomographic image data will be described later.

  Further, the image generation unit 31 performs Fourier transform on the data obtained from the line sensor 27, and obtains an image in the depth direction (Z direction) of the eye to be examined by converting the obtained data into luminance or density information. Such a scanning method is called an A scan, and the obtained tomographic image is called an A scan image.

  A plurality of A scans can be obtained by scanning the measurement light with the XY scanner 11 in a predetermined transverse direction of the eye to be examined Er, thereby acquiring a plurality of A scan images. For example, scanning in the X direction provides a plurality of A-scan images aligned on the XZ plane, and scanning in the Y direction provides a plurality of A-scan images aligned on the YZ plane. By arranging the obtained A-scan images along the scanning direction, a tomographic image along a predetermined transverse direction of the eye to be examined Er is obtained. A method of scanning the measurement light in the predetermined transverse direction on the eye to be examined in this way is called a B scan, and a tomographic image obtained by combining a plurality of A scan images aligned along the scanning direction is called a B scan image. Note that, when generating this B-scan image that is a tomographic image, the image generating unit 31 functions as a tomographic image generating unit that generates a tomographic image based on the interference signal.

  The storage unit 32 is connected to the image generation unit 31 and the display unit 102, and the image generation unit 31 generates a planar image and a tomographic image and causes the storage unit 32 to store these images.

  The display unit 102 displays the planar image 42, the tomographic image 43, and the anterior ocular segment observation image 41 acquired by the CCD 10 stored in the storage unit 32. An example of the planar image 42, the tomographic image 43, and the anterior ocular segment observation image 41 displayed on the display unit 102 is shown in FIG. In this embodiment, the display unit 102 is connected in a wired manner. However, the display unit 102 may be connected wirelessly, and further, in order to display an image generated using only recorded data. It may be connected to other configurations. In other words, it is preferable that the image displayed on the display unit 102 is displayed in accordance with an instruction from the display control unit included in the image generation unit 31.

  Next, a method for generating a planar image from a plurality of tomographic image data will be described with reference to FIGS.

  The A-scan image is a tomographic image in the depth direction at one point on the fundus of the eye to be examined, and is composed of a plurality of luminance information arranged in the depth direction as shown in FIG. 5 (left figure). For example, this apparatus uses a line sensor 27 having 2048 pixels, and the A-scan image Ai after the Fourier transform is composed of 1176 pieces of luminance information arranged in the arrow direction shown in the right retinal tomogram. . In the left figure, P0 indicates a pixel that has obtained luminance information of the shallowest portion in the depth direction, and P1175 indicates a pixel that has obtained luminance information of the deepest portion in the depth direction. This optical coherence tomography apparatus obtains a representative intensity signal at one point on the fundus of the eye to be examined by selectively extracting one piece of luminance information from the plurality of pieces of luminance information. The method will be described in detail below.

  First, as shown in FIG. 6, the present optical coherence tomography apparatus rearranges pixels for each pixel in the A-scan image in descending order of luminance based on the luminance information. Here, in the rearranged right diagram, R0 is a pixel having the brightest luminance information, and R1175 is a pixel having the darkest luminance information.

  In this optical coherence tomography apparatus, pixels Rx having a predetermined order are selected from the rearranged pixel rows R0 to R1175. Here, the pixels in the predetermined order are pixels that are located at the xth position from the top after being rearranged in the descending order of luminance information. Since most of the tomographic images of the retina are composed of dark pixels, it is desirable that Rx is a pixel positioned higher than half the total number of pixels. For example, when an A-scan image having a total number of pixels of 1176 is used, luminance information suitable for a planar image can be obtained by selecting the 118th R118 pixel from the top corresponding to the top 10% position as the pixel Rx having a predetermined order. Can do.

  The present optical coherence tomography apparatus determines the luminance information of the pixels Rx in a predetermined order as intensity information representative of the position where the A scan is performed. By similarly determining the intensity information for all the A-scan images, it is possible to obtain intensity information at different points on the fundus of the eye to be examined Er. A plane image 42 as shown in FIG. 4 can be obtained by reconstructing the intensity information as a two-dimensional image. When generating this plane image, the image generation unit 31 functions as a plane image generation unit that generates a plane image based on the interference signal.

  Since this planar image is an image similar to the fundus image obtained by another fundus camera or SLO, it is possible to visualize the fundus surface in a pseudo manner by this method. In addition, since only one piece of luminance information is selectively acquired from the plurality of pieces of luminance information, it is possible to obtain a suitable planar image without being influenced by the noise component included in the A scan image.

  In the optical coherence tomography apparatus including the data acquisition unit 100, the image processing unit 101, and the display unit 102 described above, a series of operations from observation to fundus observation of the eye to be examined will be described.

  First, observation will be described with reference to FIG. FIG. 7 individually shows the anterior ocular segment observation image 71 and the planar image 73 displayed on the display unit 102 during observation of the eye to be examined. When the subject eye Er is positioned in front of the objective lens 1, the photographer performs alignment of the subject eye Er and the data acquisition unit 100 in the XYZ directions using a joystick (not shown) while viewing the anterior eye portion observation image 71. The alignment in the XY directions is performed by positioning the pupil center of the anterior ocular segment observation image 71 at the center of the screen on which the anterior ocular segment observation image 71 is displayed. In the alignment in the Z direction, when the alignment in the Z direction is not appropriate, the anterior ocular segment observation image 71 is split vertically along the dotted line 72 in the drawing. Therefore, alignment in the Z direction is performed so that the anterior segment observation image 71 is not split.

  When the alignment of the eye to be examined Er and the data acquisition unit 100 in the XYZ directions is completed in this way, a tomographic image is generated by scanning the measurement light in the XY directions on the fundus by the XY scanner 11. Further, a planar image 73 is generated from a plurality of tomographic image data by the method described above and displayed on the display unit 102. The anterior segment observation image 71 and the planar image 73 are updated as appropriate.

  Note that a scan line 74 in the planar image 73 indicates a scanning position scanned when the tomographic image is acquired, and is superimposed on the planar image 73. The photographer operates the scanning line 74 by operating a scanning position changing means (not shown) such as a mouse or a touch panel to set a desired scanning position. Observation is completed by these operations.

  Next, photographing will be described. When a photographer operates a photographing start button (not shown), the data acquisition unit 100 and the image generation unit 31 generate a B scan image obtained by scanning the measurement light along the scan line 74. The B scan image generated by the image generation unit 31 is stored in the storage unit 32 and displayed on the display unit 102.

  In addition to the basic imaging flow from observation to imaging described above, adjustment for obtaining a clear tomographic image will be described.

  After the alignment between the eye to be examined Er and the data acquisition unit 100 is completed based on the anterior ocular segment observation image 71, the reference mirror 22 and the focus lens 12 are driven to adjust the imaging conditions of the tomographic image, thereby obtaining a clear tomographic image. An image can be obtained.

  The adjustment of the position of the reference mirror 22 is performed in order to make the optical path length of the reference light correspond to the optical path length of the measurement light, and the position adjustment of the focus lens 12 is a clear tomographic image by optimizing the intensity of the interference light. Done to get.

  These can also be controlled to be automatically adjusted. In this case, a control unit (not shown) starts automatic adjustment of the focus lens 12. That is, based on the intensity of the interference light, the position of the focus lens 12 is controlled so as to increase the intensity.

  By performing the adjustment described above, a clear tomographic image can be obtained.

  Next, OCT scanning control, which is an aspect of OCT scanning lines for obtaining a plurality of A-scan data to be aligned by scanning measurement light with the XY scanner 11, which is a feature of the present invention, will be described with reference to FIGS. 8 and 9. To do.

  FIG. 8 is a diagram showing the entire fundus image and a planar image area 81 which is a scanning range of measurement light on the fundus. FIG. 9A is a diagram showing the OCT scanning lines La1 to La10 necessary for acquiring the plane image by enlarging the plane image area 81, and FIG. FIG. 6 is a diagram showing OCT scanning lines Lb1 to Lb2 when necessary for obtaining a pair of tomographic images in the direction of. The OCT scanning lines shown in FIGS. 9A and 9B are examples, and the present invention is not limited to this. For example, in FIG. 9A, the measurement light is scanned in the X-axis direction, but this may be the Y-axis direction. In FIG. 9B, the measurement light is scanned so as to cross the papilla, but the measurement light may be scanned so as to cross the macula.

  In the present embodiment, the scanning pattern composed of OCT scanning lines Lb1 to Lb2 necessary for obtaining a tomographic image is a first scanning pattern, and the scanning pattern composed of OCT scanning lines La1 to La10 necessary for acquiring a planar image. Is a second scanning pattern. In this case, the planar image 42 and the tomographic image 43 are displayed on the display unit 102 together with the anterior ocular segment observation image 41 as shown in FIG. The planar image 42 is a planar image generated from A scan data obtained by scanning the measurement light with the second scanning pattern. The tomographic image 43 is a tomographic image generated from A scan data obtained by scanning the measurement light with the first scanning pattern.

  Further, in the OCT scanning control which is a feature of the present invention, measurement light from the same OCT light source 14 is used. A plane image generated using the second scan pattern by scanning the single measurement light with the XY scanner 11 and changing the scan pattern, and a tomographic image generated using the first scan pattern Is obtained.

  Based on the above, the automatic adjustment of the reference mirror 22 will be described.

  Automatic adjustment of the reference mirror 22 is performed in order to control the optical path length difference between the optical path length of the measurement light and the optical path length of the reference light so as to fall within a predetermined range. It is desirable to adjust the position of the reference mirror 22 by displaying a tomographic image on the display unit 102 and referring to the display state. In this case, the display position of the tomographic image is determined based on the optical path length difference (position of the reference mirror 22). The case where the optical path length difference is within a predetermined range means, for example, that the display position on the display screen of the tomographic image corresponding to the optical path length is at a predetermined display position, or a predetermined center around the position. This is the case if it is within the region. More specifically, this applies to a case where a predetermined layer in the tomographic image, for example, a layer having a high intensity, is arranged at a predetermined display position.

  Here, when the reference mirror 22 is automatically adjusted, the tomographic image that is displayed as the tomographic image 43 is used as an index. For this reason, the tomographic image used as the determination material is obtained by scanning the measurement light with the first scanning pattern. Therefore, the necessity of scanning the measurement light with the second scanning pattern is reduced.

  Therefore, during the automatic adjustment, the number of OCT scans composed of the second scan pattern is reduced or stopped, and the number of OCT scans composed of the first scan pattern is relatively increased. Thereby, it becomes possible to shorten the OCT scanning time which is the scanning time of the measuring light necessary for obtaining each image necessary for the fundus examination. In this example, shortening the OCT scanning time also means shortening the time required for the automatic adjustment.

  Note that the number of OCT scans in the second scan pattern is one scan of the measurement light along each of the scan lines La1 to La10, and the number of OCT scans that is the first scan pattern is the scan lines Lb1 to Lb2. The scanning of the measurement light along is taken once. That is, the number of OCT scans is 10 in the second scan pattern, and the number of OCT scans is 2 in the first scan pattern. The OCT scanning time is the time required to scan the measurement light along all of the scanning lines La1 to La10 shown in FIG. 9A and the scanning line Lb1 shown in FIG. 9B. It is the time required to scan the measurement light along both of ˜Lb2.

  Further, automatic adjustment of the focus lens 12 will be described.

  The automatic adjustment of the focus lens 12 is performed by controlling the position of the focus lens 12 based on the intensity of the interference light so that the intensity is increased.

  The automatic adjustment of the focus lens 12 uses either a planar image generated by scanning the measuring light with the second scanning pattern or a tomographic image generated by scanning the measuring light with the first scanning pattern. Even it can be executed. Whether or not the focus is adjusted by adjusting the position of the focus lens 12 can be determined if the maximum of the interference light intensity corresponding to the position can be detected. In the present embodiment, the planar image is generated using a plurality of tomographic images. Accordingly, the intensity of the planar image increases as the interference light intensity of the tomographic image increases. From the above, automatic position adjustment of the focus lens 12 can be executed by obtaining a tomographic image for any scanning pattern.

  Here, the number of scanning lines is smaller when the first scanning pattern is performed than when the second scanning pattern is performed. For this reason, it is possible to shorten the time required for this by using the tomographic image obtained by scanning the measurement light with the first scanning pattern for the automatic adjustment of the focus lens 12. That is, the time required for the automatic adjustment can be shortened by shortening the OCT scanning time.

  Although the automatic adjustment has been described in the above description, the OCT scanning time can be shortened also in the manual adjustment.

  For example, while the reference mirror adjustment switch (not shown) is pressed by the examiner, the number of OCT scans by the second scan pattern is reduced or stopped. At the same time, it is possible to shorten the OCT scanning time by relatively increasing the number of times of OCT scanning that is the first scanning pattern. Note that the reduction in the number of OCT scans in the second scan pattern in response to the pressing of the reference mirror adjustment switch is executed by the module area that functions as the scan number adjustment unit in the image generation unit 31. The amount of reduction may be selected from a table for a predetermined number of OCT scans, or may be automatically set according to the number of OCT scans in the second scan pattern.

  Similarly, while the adjustment switch of the focus lens 12 (not shown) is pressed by the examiner, the number of OCT scans composed of the second scan pattern is reduced or stopped, and the number of OCT scans as the first scan pattern. By relatively increasing the OCT, it is possible to shorten the OCT scanning time.

  Next, an effect by performing the above-described OCT scanning control, that is, shortening of the OCT scanning time will be described.

  For example, consider the case of automatic adjustment of the reference mirror 22. For simplicity, it is assumed that the OCT scan consisting of the second scan pattern and the OCT scan consisting of the first scan pattern are alternately performed. It is assumed that the time required as the OCT scanning time for the second scanning pattern is m, the time required as the OCT scanning time for the first scanning pattern is n, and (m> n). If x is necessary for the tomographic image necessary for automatic adjustment, the time required for automatic adjustment is mx + nx, that is, x (m + n).

  On the other hand, if the OCT scan consisting of the second scan pattern is stopped and only the OCT scan consisting of the first scan pattern is performed, the time required for automatic adjustment is nx, and the OCT scan time is shortened by mx. Is possible. The same can be said for the automatic adjustment of the focus lens 12.

  Further, consider the case of manual adjustment of the reference mirror 22. For simplicity, it is assumed that the OCT scan consisting of the second scan pattern and the OCT scan consisting of the first scan pattern are alternately performed while the reference mirror adjustment switch (not shown) is not pressed by the examiner. It is assumed that the time required as the OCT scanning time for the second scanning pattern is p, the time required as the OCT scanning time for the first scanning pattern is q, and (p> q). If r is required as long as a reference mirror adjustment switch (not shown) is pressed, the OCT scanning time is pr + qr, that is, r (p + q).

  On the other hand, if the OCT scan consisting of the second scan pattern is stopped and only the OCT scan consisting of the first scan pattern is performed, the OCT scan time becomes qr, and it is possible to shorten the OCT scan time by pr. Become. The same can be said for the manual adjustment of the focus lens 12.

  As described above, in the present embodiment, when the data acquisition unit 100 is in a predetermined condition or state, such as adjustment of the optical path length difference, position adjustment between the data acquisition unit 100 and the eye to be examined, and focus scanning. At least one of the first scanning pattern and the second scanning pattern is changed. In the present embodiment, the number of scanning lines in each scanning pattern is relatively changed. However, the concept includes the elimination of one of the scanning lines. Whether or not the data acquisition unit 100 satisfies these predetermined conditions is determined by a module area that functions as a determination unit in the data acquisition unit 100. As described above, the predetermined condition includes pressing of an adjustment switch that is a condition for starting position adjustment between the data acquisition unit 100 and the eye to be examined Er, and luminance or density in an interference signal that matches the focusing condition by the focus lens 12. That the value of is greater than or equal to a predetermined intensity is exemplified.

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

  The present invention is not limited to the above-described embodiments, and various modifications and changes can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the case where the object to be inspected is an eye has been described, but the present invention can also be applied to an object to be inspected other than the eye, such as skin or organ. In this case, the present invention has an aspect as a medical device such as an endoscope other than the ophthalmologic apparatus. Therefore, it is desirable that the present invention is grasped as an optical coherence tomography apparatus suitably used for an ophthalmologic apparatus and the like, and the eye to be examined is grasped as one aspect of the inspection object.

100: data acquisition unit 101: image processing unit 102: display unit 1: objective lens 2, 3: dichroic mirror 1, dichroic mirror 2
4: Focus lens 5: Lens 6: Fixation lamp 7: Lens 8: Split prism 9: Lens 10: CCD
11: XY scanner 12: focus lens 13: lens 14: OCT light sources 15-18: fiber 19: optical coupler 20: lens 21: dispersion compensation glass 22: reference mirror 23: spectroscope 24: lens 25: diffraction grating 26: Lens 27: Line sensor 31: Image generation unit 32: Storage unit 71: Anterior ocular segment observation image 73: Plane image 74: Scan line 81: Plane image area

Claims (10)

A data acquisition unit having a scanning unit capable of scanning measurement light with a second scanning pattern different from the first scanning pattern and the first scanning pattern on the inspection object;
An interference optical system that generates an interference signal based on interference light obtained by causing interference between the measurement light through the inspection object and reference light corresponding to the measurement light;
A tomographic image generating means for generating a tomographic image of the object to be inspected based on an interference signal by the first scanning pattern;
A plane image generating means for generating a plane image of the object to be inspected based on an interference signal by the second scanning pattern;
Control means for changing a scanning pattern of at least one of the first scanning pattern and the second scanning pattern;
An optical coherence tomography apparatus comprising: Determining means for determining whether or not the data acquisition unit satisfies a predetermined condition;
The optical coherence tomography apparatus according to claim 1, wherein the control unit changes the scanning pattern when it is determined that the determination unit satisfies a predetermined condition.   2. The control unit according to claim 1, wherein when the scan pattern is changed, the number of scan lines in the first scan pattern and the number of scan lines in the second scan pattern are relatively changed. The optical coherence tomography apparatus according to 1 or 2.   The data acquisition unit corresponds to the measurement light passing through the inspection object by changing the optical path length of the reference light by dividing the light emitted from the light source into the measurement light and the reference light. An optical coherence tomography apparatus according to any one of claims 1 to 3, further comprising a reference optical system to be operated.   5. The display control unit according to claim 1, further comprising: a display control unit configured to display on the display unit the tomographic image generated by the tomographic image generation unit and the planar image generated by the planar image generation unit. The optical coherence tomography apparatus described in 1.   The optical coherence tomography apparatus according to claim 1, wherein the predetermined condition is a condition for starting position adjustment between the data acquisition unit and the inspection object.   The optical coherence tomography apparatus according to any one of claims 1 to 6, wherein the predetermined condition is that a luminance or a density in the interference signal is equal to or higher than a predetermined intensity. The planar image acquisition means, rearrangement means for rearranging intensity information about at least luminance aligned in the depth direction of the inspection object in order of intensity with respect to the depth direction;
8. The optical coherence tomography apparatus according to claim 1, further comprising: an extracting unit that extracts intensity information of a predetermined depth in the rearranged intensity information. 9. A step of scanning the object to be inspected with the measurement light with a second scanning pattern different from the first scanning pattern and the first scanning pattern by the data acquisition unit;
Generating an interference signal based on interference light obtained by causing interference between the measurement light via the inspection object and reference light corresponding to the measurement light;
A tomographic image generating step for generating a tomographic image of the object to be inspected based on an interference signal by the first scanning pattern;
A plane image generation step of generating a plane image of the object to be inspected based on an interference signal by the second scanning pattern;
A step of changing at least one of the first scanning pattern and the second scanning pattern when the data acquisition unit and the inspection object have a predetermined relationship;
A method for controlling an optical coherence tomography apparatus, comprising:   A program for causing a computer to execute each step of the control method for an optical coherence tomography apparatus according to claim 9.