JP2014039870A - Optical image measuring apparatus and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical image measuring apparatus and an imaging apparatus capable of making measurements easily without missing measurement timing.SOLUTION: An image processing part 230 of an optical image measuring apparatus determines the propriety of the alignment state of an optical system to a subject's eye, the propriety of the focus state to a noticeable region of the eyeground, the propriety of the position of a preparatorily acquired tomographic image in a frame, the propriety of the image quality of the preparatorily acquired tomographic image, and the propriety of the tracking state of an irradiation position of a signal light to a movement of an object to be measured. When all of these conditions are determined to be proper, a control part 210 controls the optical system and an image forming part 220 to form a tomographic image of the noticeable region of the eyeground.

Description

  The present invention relates to an optical image measurement device and an imaging device that form an image representing a surface form and an internal form of an object to be measured using a light beam.

  2. Description of the Related Art In recent years, optical image measurement technology that forms an image representing a surface form or an internal form of an object to be measured using a light beam from a laser light source or the like has attracted attention. Since the optical image measurement technique does not have invasiveness to the human body unlike the X-ray CT apparatus, the development of application in the medical field and the biological field is particularly expected.

  Patent Document 1 discloses an apparatus to which an optical image measurement technique is applied. In this device, the measuring arm scans an object with a rotary turning mirror (galvanomirror), a reference mirror is installed on the reference arm, and the intensity of the interference light of the light beam from the measuring arm and the reference arm is dispersed at the exit. An interferometer is provided for analysis by the instrument. Further, the reference arm is configured to change the phase of the reference light beam stepwise by a discontinuous value.

  The apparatus of Patent Document 1 uses a so-called “Fourier Domain OCT (Fourier Domain Optical Coherence Tomography)” technique. In other words, a low-coherence beam is irradiated onto the object to be measured, the reflected light and the reference light are superimposed to generate interference light, and the spectral intensity distribution of the interference light is acquired and subjected to Fourier transform. Thus, the form of the object to be measured in the depth direction (z direction) is imaged.

  Furthermore, the apparatus described in Patent Document 1 includes a galvanometer mirror that scans a light beam (signal light), thereby forming an image of a desired measurement target region of the object to be measured. Since this apparatus is configured to scan the light beam only in one direction (x direction) orthogonal to the z direction, the image formed by this apparatus is in the scanning direction (x direction) of the light beam. It becomes a two-dimensional tomogram in the depth direction (z direction) along.

  In Patent Document 2, a plurality of two-dimensional tomographic images in the horizontal direction are formed by scanning the signal light in the horizontal direction and the vertical direction, and three-dimensional tomographic information in the measurement range is acquired based on the plurality of tomographic images. A technique for imaging is disclosed. Examples of the three-dimensional imaging include a method of displaying a plurality of tomographic images side by side in a vertical direction (referred to as stack data) and a method of rendering a plurality of tomographic images to form a three-dimensional image. Conceivable.

  Patent Documents 3 and 4 disclose other types of optical image measurement devices. Patent Document 3 scans the wavelength of light applied to an object to be measured, acquires a spectral intensity distribution based on interference light obtained by superimposing reflected light of each wavelength and reference light, On the other hand, there is described an optical image measurement device that images the form of an object to be measured by performing Fourier transform on the object. Such an optical image measurement device is called a swept source type.

  In Patent Document 4, the traveling direction of light is obtained by irradiating the object to be measured with light having a predetermined beam diameter, and analyzing the component of interference light obtained by superimposing the reflected light and the reference light. Describes an optical image measuring device that forms an image representing a form in a cross section orthogonal to the shape. Such an optical image measuring device is called a full-field type or an en-face type.

  Patent Document 5 discloses a configuration in which the OCT technique is applied to the ophthalmic field. Prior to the application of the optical image measurement device to the ophthalmology field, an ophthalmologic photographing device such as a fundus camera was used (see, for example, Patent Document 6).

  The fundus imaging apparatus using the OCT technique has an advantage that images of various depths of the fundus can be selectively acquired as compared with a fundus camera that images the fundus surface. In addition, there is an advantage that a higher-detail image can be acquired than a fundus camera. The use of such OCT technology is expected to contribute to improvement in diagnosis accuracy and early detection of lesions.

  A conventional optical image measurement device generally performs photographing in the procedure as shown in FIG. Hereinafter, as an example, a case where a fundus examination is performed using an apparatus such as Patent Document 5 will be described. First, the control lever is operated to align the apparatus optical system with the eye to be examined (S101). This operation is performed, for example, by projecting a bright spot on the eye to be examined by the alignment optical system and operating the control lever so that the bright spot displayed on the screen is arranged in a bracket-shaped scale.

  Next, the apparatus optical system is focused (focused) on a region of interest of the eye to be examined (for example, the macula, optic nerve head, etc.) (S102). This operation is performed, for example, by projecting a focusing target on the eye to be examined using a predetermined optical system and operating a focusing handle. More specifically, a split bright line composed of two straight bright lines is projected as a focus target, and the focusing handle is operated so that the two bright lines are arranged in a straight line. .

  When the focus is completed, the interference image is searched and displayed (S103). In this operation, an interference image at a desired depth position of the fundus is displayed by adjusting the optical path length of the reference light. At that time, the optical path length is adjusted to improve the image quality at a desired depth position. The adjustment of the optical path length may be performed manually by an operator, or may be performed automatically by acquiring and analyzing an interference image.

  Subsequently, a predetermined button is pressed to start auto tracking (S104). Auto-tracking is a technique for causing a light beam (signal light) to follow the movement of the eye to be inspected so that the region of interest is arranged approximately at the center of the interference image. This technique is disclosed in, for example, Patent Documents 7 to 10.

  The operator presses the photographing switch at a desired timing while performing auto-tracking (S105). In response, the apparatus acquires an interference image (S106), and further captures a fundus image (S107).

JP 11-325849 A JP 2002-139421 A JP 2007-24677 A JP 2006-153838 A JP 2008-289579 A JP-A-9-276232 JP 2008-342 A JP 2008-343 JP 2008-154725 A JP 2008-154726 A

  When the inspection is performed according to the above-described procedure, it may be difficult to determine whether the alignment, focus, interference image position adjustment, image quality, and auto-tracking states are suitable. In particular, this determination is difficult for an examiner who is not skilled in using the optical image measurement device, and there is a high risk of missing the measurement timing. Even a certain level of skill cannot say that there is no risk of missing the measurement timing.

  In addition, some conventional ophthalmologic photographing apparatuses such as a fundus camera have a function of automatically taking an image by determining the alignment or focus state, but this can be applied to an optical image measuring apparatus as it is. Have difficulty. This is because the image (interference image) obtained by the optical image measurement device is finer than the fundus image, and the interference image covers a narrower range than the fundus image. This is because there is a risk of becoming. Also, the position adjustment and image quality of the interference image cannot be handled by conventional techniques.

  The present invention has been made to solve such a problem, and an object thereof is to provide an optical image measurement device and a photographing device capable of easily performing measurement without missing measurement timing. .

  In order to achieve the above object, the invention according to claim 1 divides light from a light source into signal light and reference light, and the signal light passing through the object to be measured and the reference light passing through the reference object. And an optical system that generates interference light by detecting the interference light and generates a detection signal, and an image forming unit that forms an image of the object to be measured based on the detection signal An image measurement apparatus, comprising: an alignment unit that aligns the optical system with respect to the object to be measured; a focusing unit that focuses the optical system with respect to the object to be measured; and a predetermined frame based on the detection signal Image position determining means for determining the position of the image in the image; determining whether the position of the optical system is appropriate and whether the focus state is appropriate; determining the appropriateness of the position of the image in the predetermined frame; Suitable for the position of Determination means for determining whether or not the in-focus state is appropriate and determining the appropriateness of the position of the image after completion of the determination, the determination means for determining all the appropriateness again, and the optical system in the re-adequacy determination. When it is determined that the position, the in-focus state, and the position of the image are all appropriate, the optical system and the image forming unit can be controlled to acquire an image of the object to be measured. And a control means.

  The invention according to claim 2 is the optical image measurement device according to claim 1, wherein the determination means has an upper end region and a lower end region of an image of the object to be measured arranged in the frame. Thus, the position of the image is determined as described above.

  The invention according to claim 3 is an optical system for acquiring an image of the eye to be examined, alignment means for aligning the optical system with respect to the eye to be examined, and focusing of the optical system with respect to the eye to be examined. Focusing means for performing image processing, image position determination means for determining the position of the image of the subject eye within a predetermined frame after the image of the subject eye is preliminarily acquired using the optical system, and the optical system Whether the position of the optical system is appropriate and whether the focus state is appropriate, whether the position of the image of the subject eye within the predetermined frame is appropriate, whether the optical system is appropriate, and whether the focus state is appropriate After all of the determination and the determination of the appropriateness of the position of the image of the eye to be examined are completed, determination means for re-determining all the appropriateness, and the position of the optical system and the in-focus state in the appropriateness determination again And the said An imaging apparatus comprising: control means for controlling the optical system to enable acquisition of the image of the eye to be examined when it is determined that all the positions of the image of the optometry are appropriate. is there.

  The optical image measurement apparatus according to the present invention includes a frame of a tomographic image of an attention area of an object to be measured formed by an image forming unit, and whether or not an optical system is properly positioned by an alignment unit. In this case, it is determined whether each position is appropriate or not, and when it is determined that all three conditions are appropriate, a tomographic image of the region of interest can be acquired.

  In addition to the above three conditions, another aspect of the optical image measurement device according to the present invention determines whether the image quality of the tomographic image is appropriate and whether the tracking state of the irradiation position of the signal light is appropriate. It is possible to acquire a tomographic image of a region of interest when it is determined that all of these are appropriate.

  According to such an invention, for example, even when a tomographic image of a measured object such as a living eye is acquired, it is easy to miss the timing when the above various conditions are appropriate, that is, the measurement timing. It is possible to perform measurement.

It is the schematic showing an example of the whole structure of embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of the structure of the alignment optical system in embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of a structure of the OCT unit in embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of the display screen in embodiment of the optical image measuring device which concerns on this invention. It is a schematic block diagram showing an example of the structure of the control system of embodiment of the optical image measuring device which concerns on this invention. It is a flowchart showing an example of operation | movement of embodiment of the optical image measuring device which concerns on this invention. It is a flowchart showing an example of operation | movement of embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of the display screen in embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of the display screen in embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of the display screen in embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of the display screen in embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of the display screen in embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of the display screen in embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of the display screen in embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of the display screen in embodiment of the optical image measuring device which concerns on this invention. It is a flowchart showing an example of operation | movement of the conventional optical image measuring device.

  An example of an embodiment of an optical image measurement device according to the present invention will be described in detail with reference to the drawings. In this embodiment, an apparatus that is used in the ophthalmic field and acquires an OCT image of a living eye will be described. In addition, even when acquiring an OCT image of an object to be measured other than a living eye, the same operation and effect can be obtained with the same configuration.

  In this embodiment, a configuration to which a Fourier domain type technique is applied will be described in detail. In particular, in this embodiment, an optical image measurement device having substantially the same configuration as the device disclosed in Patent Document 5 is taken up. Even when other configurations are applied, the same operations and effects can be obtained by applying the same configuration as that of this embodiment. For example, the configuration according to this embodiment can be applied to any type of OCT technology that scans signal light such as a swept source type. In addition, the configuration according to this embodiment can be applied to an OCT technique in which signal light is not scanned in the horizontal direction as in the full field type.

[Constitution]
As shown in FIG. 1, the optical image measurement device 1 includes a fundus camera unit 1 </ b> A, an OCT unit 150, and an arithmetic control device 200. Each of these units may be provided in a plurality of cases, or may be provided in a single case. The fundus camera unit 1A has an optical system that is substantially the same as that of a conventional fundus camera. A fundus camera is a device that photographs the fundus. In addition, the fundus camera is used for photographing a fundus blood vessel. The OCT unit 150 stores an optical system for acquiring an OCT image of the eye to be examined. The arithmetic and control unit 200 includes a computer that executes various arithmetic processes and control processes.

  One end of a connection line 152 is attached to the OCT unit 150. A connector 151 for connecting the connection line 152 to the retinal camera unit 1A is attached to the other end of the connection line 152. An optical fiber 152a is conducted inside the connection line 152 (see FIG. 3). The OCT unit 150 and the fundus camera unit 1A are optically connected via a connection line 152. The arithmetic and control unit 200 is connected to each of the fundus camera unit 1A and the OCT unit 150 via a communication line that transmits an electrical signal.

[Fundus camera unit]
The fundus camera unit 1A includes an optical system for forming a two-dimensional image representing the form of the fundus surface. Here, the two-dimensional image of the fundus surface includes a color image and a monochrome image obtained by photographing the fundus surface, and further a fluorescent image (fluorescein fluorescent image, indocyanine green fluorescent image, etc.) and the like.

  The retinal camera unit 1A is provided with various user interfaces as in the conventional retinal camera. Examples of the user interface include an operation panel, a control lever (joystick), a photographing switch, a focusing handle, a display, and the like. Various switches and buttons are provided on the operation panel. The control lever is operated to three-dimensionally move a gantry provided with an operation panel or the like, or an apparatus main body incorporating an optical system with respect to the apparatus base. The control lever is used particularly during manual alignment operations. The imaging switch is provided at the upper end of the control lever, and is used to instruct acquisition of a fundus image or an OCT image. The photographing switch is also used when performing other functions. The operation panel and the control lever are provided at the position (rear surface) on the examiner side of the fundus camera unit 1A. The focusing handle is provided on the side surface of the apparatus main body, for example, and is used for focus adjustment (focusing). When the focusing handle is operated, a focusing lens described later is moved to change the focus state. The display is provided at a position on the examiner side of the fundus camera unit 1 </ b> A and displays various information such as an image acquired by the optical image measurement device 1, patient information, and imaging conditions. A chin rest and a forehead for holding the face of the subject are provided at a position (front surface) on the subject side of the fundus camera unit 1A.

  The fundus camera unit 1A is provided with an illumination optical system 100 and a photographing optical system 120, as in a conventional fundus camera. The illumination optical system 100 irradiates the fundus oculi Ef with illumination light. The imaging optical system 120 guides the fundus reflection light of the illumination light to the imaging devices 10 and 12. The imaging optical system 120 guides the signal light from the OCT unit 150 to the fundus oculi Ef and guides the signal light passing through the fundus oculi Ef to the OCT unit 150.

  The illumination optical system 100 includes an observation light source 101, a condenser lens 102, a photographing light source 103, a condenser lens 104, exciter filters 105 and 106, a ring translucent plate 107, a mirror 108, an LCD (Liquid Crystal Display), as in a conventional fundus camera. ) 109, an illumination aperture 110, a relay lens 111, a perforated mirror 112, and an objective lens 113.

  The observation light source 101 outputs illumination light including a near-infrared wavelength in the range of about 700 nm to 800 nm, for example. This near-infrared light is set shorter than the wavelength of light used in the OCT unit 150 (described later). The imaging light source 103 outputs illumination light including wavelengths in the visible region in the range of about 400 nm to 700 nm, for example.

  The illumination light output from the observation light source 101 is perforated through condenser lenses 102 and 104, (exciter filter 105 or 106) ring translucent plate 107, mirror 108, reflector 109 b, illumination diaphragm 110, and relay lens 111. The mirror 112 is reached. Further, the illumination light is reflected by the perforated mirror 112 and enters the eye E through the objective lens 113 to illuminate the fundus oculi Ef. On the other hand, the illumination light output from the imaging light source 103 similarly enters the eye E through the condenser lens 104 to the objective lens 113 and illuminates the fundus oculi Ef.

  The photographing optical system 120 includes an objective lens 113, a perforated mirror 112 (hole 112a), a photographing aperture 121, barrier filters 122 and 123, a focusing lens 124, a relay lens 125, a photographing lens 126, a dichroic mirror 134, and a field lens. (Field lens) 128, half mirror 135, relay lens 131, dichroic mirror 136, photographing lens 133, imaging device 10, reflection mirror 137, photographing lens 138, imaging device 12, lens 139 and LCD 140 are configured. The photographing optical system 120 has substantially the same configuration as a conventional fundus camera. The focusing lens 124 is movable in the optical axis direction of the photographing optical system 120.

  The dichroic mirror 134 reflects fundus reflection light (having a wavelength included in a range of about 400 nm to 800 nm) of illumination light from the illumination optical system 100. The dichroic mirror 134 transmits the signal light LS (for example, having a wavelength included in the range of about 800 nm to 900 nm; see FIG. 3) from the OCT unit 150.

  The dichroic mirror 136 reflects the fundus reflection light of the illumination light from the observation light source 101 and transmits the fundus reflection light of the illumination light from the imaging light source 103.

  The LCD 140 displays a fixation target (internal fixation target) for fixing the eye E to be examined. Light from the LCD 140 is collected by the lens 139, reflected by the half mirror 135, and reflected by the dichroic mirror 136 via the field lens 128. Further, this light is incident on the eye E through the photographing lens 126, the relay lens 125, the focusing lens 124, the aperture mirror 112 (the aperture 112a thereof), the objective lens 113, and the like. Thereby, the internal fixation target is projected onto the fundus oculi Ef.

  By changing the display position of the internal fixation target by the LCD 140, the fixation direction of the eye E can be changed. As the fixation direction of the eye E, for example, as with a conventional fundus camera, a fixation direction for acquiring an image centered on the macular portion of the fundus oculi Ef or an image centered on the optic disc is acquired. And the fixation direction for acquiring an image centered on the fundus center between the macula and the optic disc. The fixation position is changed, for example, by operating the operation panel.

  The imaging device 10 includes an imaging element 10a. The imaging device 10 can particularly detect light having a wavelength in the near infrared region. That is, the imaging device 10 functions as an infrared television camera that detects near-infrared light. The imaging device 10 detects near infrared light and outputs a video signal. The imaging element 10a is an arbitrary imaging element (area sensor) such as a CCD (Charge Coupled Devices) or a CMOS (Complementary Metal Oxide Semiconductor).

  The imaging device 12 includes an imaging element 12a. The imaging device 12 can particularly detect light having a wavelength in the visible region. That is, the imaging device 12 functions as a television camera that detects visible light. The imaging device 12 detects visible light and outputs a video signal. The image sensor 12a is configured by an arbitrary image sensor (area sensor), similarly to the image sensor 10a.

  The touch panel monitor 11 displays a fundus oculi image Ef ′ based on the video signals from the image sensors 10a and 12a. The video signal is sent to the arithmetic and control unit 200. The touch panel monitor 11 is an example of the display described above.

  The fundus camera unit 1A is provided with a scanning unit 141 and a lens 142. The scanning unit 141 scans the irradiation position of the signal light LS output from the OCT unit 150 to the fundus oculi Ef.

  The scanning unit 141 scans the signal light LS on the xy plane shown in FIG. For this purpose, the scanning unit 141 is provided with, for example, a galvanometer mirror for scanning in the x direction and a galvanometer mirror for scanning in the y direction.

  The reflector 109b of the illumination optical system 100 constitutes a focusing optical system together with the LED 109a. The focusing optical system projects a visual target (split bright line) used for focus adjustment onto the eye E as in a conventional fundus camera. The reflecting rod 109b can be inserted into and removed from the optical axis of the illumination optical system 100. One end of the reflecting rod 109 b has a reflecting surface that is inclined with respect to the optical axis of the illumination optical system 100. The output light from the LED 109a is reflected by the reflecting surface and projected onto the eye E through the same path as the illumination light.

  The focusing optical system is moved in the optical axis direction of the illumination optical system 100 in conjunction with the movement of the focusing lens 124 so that the reflecting surface of the reflecting bar 109b and the fundus oculi Ef are optically conjugate. . When the reflecting surface and the fundus oculi Ef are not conjugated, the pair of split bright lines appear to be separated in the left-right direction without being aligned on a straight line. On the other hand, when the reflecting surface and the fundus oculi Ef are conjugated, the pair of split bright lines appear to be aligned. Focus adjustment can be performed using this. Such focus adjustment using split emission lines is widely used in conventional fundus cameras and the like.

  A half mirror 190 is obliquely provided on the optical path between the focusing lens 124 and the relay lens 125. The half mirror 190 acts to synthesize the optical path of the alignment optical system 190A shown in FIG. 2A and the optical path of the imaging optical system 120 (imaging optical path). The alignment optical system 190A is an optical system for projecting the alignment bright spot used for the alignment (alignment) of the optical system with respect to the eye E to the eye E.

  The alignment bright spot is an alignment (alignment in the xy direction shown in FIG. 1) that aligns the apex of the cornea of the eye E with the optical axes of the optical systems 100 and 120, and the distance between the eye E and the optical systems 100 and 120. (Z direction in FIG. 1; working distance; distance between the cornea (vertex) of the eye E and the objective lens 113) (for example, Japanese Patent Laid-Open No. 11-4808) reference).

  As shown in FIG. 2A, the alignment optical system 190A includes an alignment light source 190a, a light guide 190b, a reflection mirror 190c, a two-hole aperture 190d, and a relay lens 190e together with the half mirror 190. The alignment light source 190a is configured by a light source such as an LED that outputs light in the near infrared region (alignment light), for example.

  The two-hole aperture 190d has two holes 190d1 and 190d2 as shown in FIG. The holes 190d1 and 190d2 are formed at positions symmetrical with respect to the center position 190d3 of the disc-shaped two-hole aperture 190d, for example. The two-hole aperture 190d is disposed such that the center position 190d3 is positioned on the optical axis of the alignment optical system 190A.

  The alignment light emitted from the emission end 190β of the light guide 190b is reflected by the reflection mirror 190c and guided to the two-hole aperture 190d. The alignment light (a part) that has passed through the holes 190d1 and 190d2 of the two-hole aperture 190d is reflected by the half mirror 190 and guided to the perforated mirror 112 via the relay lens 190e. At this time, the relay lens 190e forms an intermediate image of the image of the exit end 190β of the light guide 190b at the center position of the hole 112a of the perforated mirror 112 (position on the optical axis of the photographing optical system 120). The alignment light that has passed through the hole 112 a of the perforated mirror 112 is projected onto the cornea of the eye E through the objective lens 113.

  Here, when the positional relationship between the eye E and the fundus camera unit 1A (objective lens 113) is appropriate, that is, the distance (working distance) between the eye E and the fundus camera unit 1A is appropriate. In addition, when the optical axis of the optical system of the fundus camera unit 1A and the eye axis (corneal apex position) of the eye E to be examined are (almost) coincident, two light beams (alignment light beams) formed by the two-hole aperture 190d Are projected on the eye E to be imaged at intermediate positions between the apex of the cornea and the center of curvature of the cornea.

  The corneal reflection light of the two alignment light beams (alignment light) is received by the image sensor 10 a via the photographing optical system 120. An image captured by the image sensor 10a is displayed on a display device such as a touch panel monitor 11 or a display (described later) of the arithmetic and control unit 200.

  Here, the focus adjustment and the alignment adjustment will be described with reference to FIG. This display screen is displayed on the touch panel monitor 11, for example. Information presented on this display screen includes patient ID 301; left and right eye information 302, photographing light source charging information 303, photographing light amount correction information 304, photographing light amount level information 305, automatic photographing information 306, angle of view information 307, fixation position. There are information 308, an alignment scale 309, a pair of alignment bright spots 310, a pair of split bright lines 311, observation light quantity level information 312, and small pupil information 313.

  The left and right eye information 302 is information indicating whether the eye E is the left eye (L) or the right eye (R). The imaging light source charging information 303 is information representing the charging state of the imaging light source 103 (xenon lamp). The photographing light amount correction information 304 is information representing a photographing light amount correction value set on the operation panel. The photographing light amount level information 305 is information representing a setting value of the photographing light amount. The automatic shooting information 306 is presented when a function for automating shooting work such as autoshoot (automatic shooting) or autofocus is turned on. The angle-of-view information 307 is information representing a set value of a shooting angle of view (shooting magnification). The fixation position information 308 is information representing a set value of the fixation position (fixation direction) of the eye E. The observation light quantity level information 312 is information representing a set value of the observation light quantity. The small pupil information 313 is presented when a small pupil diaphragm (not shown) used when the eye E is a small pupil is applied.

  The alignment will be described. The pair of alignment bright spots 310 are light reception images of light projected onto the eye E by the alignment optical system 190A. The alignment scale 309 is a parenthesis-type image that represents a position that is a movement target of the pair of alignment bright spots 310. The examiner performs the alignment of the optical system with respect to the eye E by operating the control lever and moving the fundus camera unit 1 </ b> A three-dimensionally so that the pair of alignment bright spots 310 enter the alignment scale 309. .

  Instead of manually adjusting the alignment as described above, an automatic (automatic) alignment function can be applied. In the auto alignment, for example, the position of each alignment luminescent spot 310 in the display screen is specified, a shift between each specified position and the alignment scale 309 is obtained, and the fundus camera unit 1A is moved so as to cancel this shift. To do so. The position of each alignment bright spot 310 can be determined by, for example, obtaining the brightness distribution of each alignment bright spot and obtaining the center of gravity position based on this brightness distribution. Since the position of the alignment scale 309 is constant, the deviation can be obtained by obtaining the displacement between the center position and the gravity center position, for example. The movement direction and movement distance of the fundus camera unit 1A are set as unit movement distances in the preset x, y, and z directions (for example, how much the fundus camera unit 1A is moved in which direction and how much the alignment brightness changes). It is possible to determine with reference to a result of measuring in advance in which direction and how much the point 310 moves. In the case of performing auto alignment, an actuator (such as a pulse motor) for moving the fundus camera unit 1A is provided.

  Focus adjustment will be described. The pair of split bright lines 311 are presented side by side in the vertical direction. The examiner operates the focusing handle to move the focusing lens 124 and the focusing optical system in order to perform focus adjustment. Accordingly, the upper and lower split bright lines 311 move in the left-right direction. The examiner performs focusing by operating the focusing handle so that the upper and lower split bright lines 311 are positioned on a straight line extending vertically.

  Instead of manually adjusting the focus in this way, an autofocus function can be applied. Autofocus is performed, for example, by specifying the display position of each split bright line 311 and determining the moving direction and moving distance of the focusing lens 124 and the like so that the upper and lower split bright lines 311 are positioned on a straight line. The display position of each split bright line 311 can be determined by, for example, obtaining the barycentric position from the luminance distribution of each split bright line 311. The moving direction and moving distance are, for example, preset unit moving distances (for example, how much the focusing lens 124 is moved in which direction and how much the split bright line 311 moves in which direction and how much in advance. It is possible to determine with reference to the measurement result).

[OCT unit]
Next, the configuration of the OCT unit 150 will be described with reference to FIG. The OCT unit 150 includes an optical system similar to that of a conventional Fourier domain type optical image measurement device. That is, the OCT unit 150 divides low-coherence light into reference light and signal light, and generates interference light by causing the signal light passing through the fundus of the eye to be examined and the reference light passing through the reference object to generate interference light. An optical system for detecting light and generating a detection signal is provided. This detection signal is sent to the arithmetic and control unit 200.

  The low coherence light source 160 is a broadband light source that outputs a broadband low coherence light L0. As this broadband light source, for example, a super luminescent diode (SLD), a light emitting diode (LED), or the like can be used.

  The low coherence light L0 includes, for example, light having a wavelength in the near infrared region, and has a temporal coherence length of about several tens of micrometers. The low coherence light L0 includes a wavelength longer than the illumination light (wavelength of about 400 nm to 800 nm) of the fundus camera unit 1A, for example, a wavelength in the range of about 800 nm to 900 nm.

  The low coherence light L0 output from the low coherence light source 160 is guided to the optical coupler 162 through the optical fiber 161. The optical fiber 161 is configured by, for example, a single mode fiber or a PM fiber (Polarization maintaining fiber). The optical coupler 162 splits the low coherence light L0 into the reference light LR and the signal light LS.

  The optical coupler 162 has both the functions of a means for splitting light (splitter) and a means for superposing light (coupler), but here it is conventionally referred to as an “optical coupler”.

  The reference light LR generated by the optical coupler 162 is guided by an optical fiber 163 made of a single mode fiber or the like and emitted from the end face of the fiber. Further, the reference light LR is converted into a parallel light beam by the collimator lens 171 and is reflected by the reference mirror 174 via the glass block 172, the polarizing plate (λ / 4 plate) 175 and the density filter 173. The reference mirror 174 is an example of the “reference object” in the present invention.

  The reference light LR reflected by the reference mirror 174 passes through the density filter 173, the polarizing plate 175, and the glass block 172 again, is condensed on the fiber end surface of the optical fiber 163 by the collimator lens 171, and passes through the optical fiber 163 to the optical coupler 162. Led to.

  The glass block 172 and the density filter 173 function as delay means for matching the optical path lengths (optical distances) of the reference light LR and the signal light LS. Further, the glass block 172 and the density filter 173 function as dispersion compensation means for matching the dispersion characteristics of the reference light LR and the signal light LS.

  The density filter 173 functions as a neutral density filter that reduces the amount of the reference light LR. The density filter 173 is configured by, for example, a rotary ND (Neutral Density) filter. The density filter 173 is rotationally driven by a drive mechanism (not shown) to change the amount of the reference light LR that contributes to the generation of the interference light LC.

  The polarizing plate 175 is used to correct the optical path length of the reference light LR and is used to improve the image quality of the OCT image. The polarizing plate 175 is disposed so as to be inclined by, for example, about 3 degrees with respect to the direction orthogonal to the optical path direction of the reference light LR. The polarizing plate 175 is rotationally driven by a predetermined driving mechanism, thereby adjusting the image quality of the interference image.

  The reference mirror 174 is moved in the traveling direction of the reference light LR (the direction of the double-sided arrow shown in FIG. 3) by a predetermined driving mechanism. Thereby, the optical path length of the reference light LR can be ensured according to the axial length of the eye E and the working distance (distance between the objective lens 113 and the eye E).

  On the other hand, the signal light LS generated by the optical coupler 162 is guided to the end of the connection line 152 by an optical fiber 164 made of a single mode fiber or the like. Here, the optical fiber 164 and the optical fiber 152a may be formed from a single optical fiber, or may be formed integrally by joining the respective end faces.

  The signal light LS is guided by the optical fiber 152a and guided to the fundus camera unit 1A. Further, the signal light LS includes the lens 142, the scanning unit 141, the dichroic mirror 134, the photographing lens 126, the relay lens 125, the half mirror 190, the focusing lens 124, the photographing aperture 121, the hole 112a of the aperture mirror 112, the objective lens. The eye E is irradiated to the eye E via 113 and irradiated to the fundus Ef. When irradiating the fundus oculi Ef with the signal light LS, the barrier filters 122 and 123 are retracted from the optical path in advance.

  The signal light LS incident on the eye E is imaged and reflected on the fundus oculi Ef. At this time, the signal light LS is not only reflected by the surface of the fundus oculi Ef, but also reaches the deep region of the fundus oculi Ef and is scattered at the refractive index boundary. Therefore, the signal light LS passing through the fundus oculi Ef includes information reflecting the surface form of the fundus oculi Ef and information reflecting the state of backscattering at the refractive index boundary of the deep tissue of the fundus oculi Ef. This light may be simply referred to as “fundus reflected light of the signal light LS”.

  The fundus reflection light of the signal light LS is guided in the reverse direction along the same path as the signal light LS toward the eye E to be collected on the end surface of the optical fiber 152a. Further, the fundus reflection light of the signal light LS enters the OCT unit 150 through the optical fiber 152 a and returns to the optical coupler 162 through the optical fiber 164.

  The optical coupler 162 superimposes the signal light LS returned via the fundus oculi Ef and the reference light LR reflected by the reference mirror 174 to generate the interference light LC. The interference light LC is guided to the spectrometer 180 through an optical fiber 165 made of a single mode fiber or the like.

  The spectrometer (spectrometer) 180 detects the spectral component of the interference light LC. The spectrometer 180 includes a collimator lens 181, a diffraction grating 182, an imaging lens 183, and a CCD 184. The diffraction grating 182 may be transmissive or reflective. Further, in place of the CCD 184, other light detection elements (line sensor or area sensor) such as CMOS may be used.

  The interference light LC incident on the spectrometer 180 is converted into a parallel light beam by the collimator lens 181, and is split (spectral decomposition) by the diffraction grating 182. The split interference light LC is imaged on the imaging surface of the CCD 184 by the imaging lens 183. The CCD 184 detects each spectral component of the separated interference light LC and converts it into electric charges. The CCD 184 accumulates this electric charge and generates a detection signal. Further, the CCD 184 sends this detection signal to the arithmetic and control unit 200.

  In this embodiment, a Michelson interferometer is used. However, for example, any type of interferometer such as a Mach-Zehnder type can be appropriately used.

[Calculation control device]
The configuration of the arithmetic and control unit 200 will be described. The arithmetic and control unit 200 analyzes the detection signal input from the CCD 184 and forms an OCT image of the fundus oculi Ef. The arithmetic processing for this is the same as that of a conventional Fourier domain type optical image measurement device.

  The arithmetic and control unit 200 controls each part of the fundus camera unit 1A and the OCT unit 150.

  As control of the fundus camera unit 1A, the arithmetic control device 200 controls the output of illumination light by the observation light source 101 and the imaging light source 103, and controls the insertion / retraction operation of the exciter filters 105 and 106 and the barrier filters 122 and 123 on the optical path. , Operation control of display device such as LCD 140, movement control of illumination diaphragm 110 (control of aperture value), control of aperture value of photographing diaphragm 121, movement control of focusing lens 124 (focus adjustment, magnification adjustment), focusing optics The system and alignment optical system 190A are controlled. Further, the arithmetic and control unit 200 controls the scanning unit 141 to scan the signal light LS.

  Further, as the control of the OCT unit 150, the arithmetic and control unit 200 controls the output of the low coherence light L0 by the low coherence light source 160, the movement control of the reference mirror 174, and the rotation operation of the density filter 173 (the amount of decrease in the light amount of the reference light LR). Control), charge accumulation time by CCD 184, charge accumulation timing, signal transmission timing, and the like.

  The arithmetic and control unit 200 includes a microprocessor, a RAM, a ROM, a hard disk drive, a keyboard, a mouse, a display, a communication interface, and the like, like a conventional computer. The hard disk drive stores a computer program for controlling the optical image measurement device 1. Further, the arithmetic and control unit 200 may include a dedicated circuit board that forms an OCT image based on a detection signal from the CCD 184.

[Control system]
The configuration of the control system of the optical image measurement device 1 will be described with reference to FIG. 5, the imaging devices 10 and 12 are described separately from the fundus camera unit 1A, and the CCD 184 is described separately from the OCT unit 150. However, as described above, the imaging devices 10 and 12 are included in the fundus oculi. Mounted on the camera unit 1 </ b> A, the CCD 184 is mounted on the OCT unit 150.

(Control part)
The control system of the optical image measurement device 1 is configured around the control unit 210 of the arithmetic and control device 200. The control unit 210 includes, for example, the aforementioned microprocessor, RAM, ROM, hard disk drive, communication interface, and the like. The control unit 210 is an example of the “control unit” in the present invention.

  The control unit 210 is provided with a main control unit 211 and a storage unit 212. The main control unit 211 controls each part of the fundus camera unit 1 </ b> A, the OCT unit 150, and the arithmetic control device 200.

  The storage unit 212 stores various data. Examples of data stored in the storage unit 212 include image data of an OCT image, image data of a fundus oculi image Ef ′, and eye information to be examined. The eye information includes, for example, various information related to the eye such as information about the subject such as patient ID and name, left eye / right eye identification information, and diagnosis / test results of the eye. The main control unit 211 performs a process of writing data to the storage unit 212 and a process of reading data from the storage unit 212.

  Further, the storage unit 212 stores data of a unit movement distance (described above) in alignment adjustment and focus adjustment. Further, the storage unit 212 stores a computer program for executing an operation (flow chart) described later. The main control unit 211 operates based on the data and the computer program.

(Image forming part)
The image forming unit 220 forms tomographic image data of the fundus oculi Ef based on the detection signal from the CCD 184. This image data forming process includes processes such as noise removal (noise reduction), filter processing, and FFT (Fast Fourier Transform), as in the conventional Fourier domain type OCT technique.

  The image forming unit 220 includes, for example, the above-described circuit board and communication interface. The image forming unit 220 is an example of the “image forming unit” in the present invention. In this specification, “image data” and “image” displayed based on the “image data” may be identified.

(Image processing unit)
The image processing unit 230 performs various types of image processing and analysis processing on the fundus image (captured image of the fundus surface) acquired by the fundus camera unit 1A and the tomographic image formed by the image forming unit 220. For example, the image processing unit 230 executes various correction processes such as image brightness correction and dispersion correction.

  In addition, the image processing unit 230 forms image data of a three-dimensional image of the fundus oculi Ef by executing an interpolation process for interpolating pixels between tomographic images formed by the image forming unit 220.

  Note that the image data of a three-dimensional image means image data in which pixel positions are defined by a three-dimensional coordinate system. As image data of a three-dimensional image, there is image data composed of voxels arranged three-dimensionally. This image data is called volume data or voxel data. When displaying an image based on volume data, the image processing unit 230 performs rendering processing (volume rendering, MIP (Maximum Intensity Projection), etc.) on the volume data, and views the image from a specific gaze direction. Image data of a pseudo three-dimensional image is formed. This pseudo three-dimensional image is displayed on a display device such as the display unit 240.

  It is also possible to form stack data of a plurality of tomographic images as image data of a three-dimensional image. The stack data is image data obtained by three-dimensionally arranging a plurality of tomographic images obtained along a plurality of scanning lines based on the positional relationship of the scanning lines. That is, the stack data is image data obtained by expressing a plurality of tomographic images originally defined by individual two-dimensional coordinate systems using one three-dimensional coordinate system (that is, embedding in one three-dimensional space). is there. The image processing unit 230 can also perform various image processing and analysis processing on the three-dimensional image.

  The image processing unit 230 includes an alignment determination unit 231, an in-focus determination unit 232, an image position determination unit 233, an image quality determination unit 234, and a tracking determination unit 235. Each of these determination units 231 to 235 constitutes a part of “determination means” of the present invention.

  The alignment determination unit 231 determines whether the position of the optical system is appropriate, that is, whether the optical system is positioned at an appropriate position with respect to the eye E at a predetermined timing after the alignment adjustment of the optical system. As described above, the alignment determination unit 231 determines the suitability of the alignment state at a predetermined timing after alignment adjustment. Even after the alignment adjustment, the alignment state may change due to the eye movement of the eye E, the movement of the subject, and the like, so such alignment determination is effective.

  An example of processing executed by the alignment determination unit 231 will be described. The alignment determination unit 231 analyzes the fundus image of the eye E acquired in a state where the alignment bright spot 310 is projected after the alignment adjustment (see FIG. 4). Here, the position of the alignment scale 309 in the fundus image frame is known (constant).

  First, the alignment determination unit 231 specifies the positions (center of gravity positions, etc.) of the pair of alignment bright spots 310 in the manner described above. Subsequently, the alignment determination unit 231 determines whether or not these specific positions are within a predetermined allowable range, that is, within the alignment scale 309 (parenthesis-shaped image). When it is determined that these specific positions are within the allowable range, the alignment determination unit 231 determines that the alignment state is appropriate. On the other hand, when these specific positions are not within the allowable range, the alignment determination unit 231 determines that the alignment state is not appropriate. A specific example of the process for determining the suitability of the alignment state is described in, for example, Japanese Patent Application No. 2008-13989 by the present applicant.

  The focus determination unit 232 determines whether or not the focus state is appropriate, that is, whether or not the fundus oculi Ef is properly focused (whether or not the focus is in focus) at a predetermined timing after focus adjustment. . Even after the focus adjustment, the alignment state is effective because the focus state may change due to the eye movement of the eye E or the movement of the subject.

  An example of processing executed by the focus determination unit 232 will be described. The in-focus determination unit 232 analyzes the fundus image of the eye E acquired with the split bright line 311 projected after focus adjustment (see FIG. 4).

  First, the focus determination unit 232 specifies the position (center of gravity position) of the upper and lower split bright lines 311 in the left-right direction as described above. Subsequently, the focus determination unit 232 determines whether these specific positions are within an allowable range in the left-right direction. This allowable range is set in advance. Thereby, it is determined whether or not the upper and lower split bright lines 311 are arranged on a substantially straight line. When it is determined that these specific positions are within the allowable range, the focus determination unit 232 determines that the focus state is appropriate. On the other hand, when these specific positions are not within the allowable range, the focus determination unit 232 determines that the focus state is not appropriate. A specific example of the process for determining the suitability of the focus state is described in, for example, Japanese Patent Application No. 2008-13989 by the present applicant.

  The image position determination unit 233 determines whether the position of the tomographic image of the fundus oculi Ef within the frame is appropriate. In particular, the image position determination unit 233 determines whether or not the depth position (position in the z direction) of the tomographic image in the frame is appropriate.

  A tomographic image is generally obtained after alignment adjustment and focus adjustment, so that an image corresponding to the fundus surface (retina surface) appears in the frame. The image position determination unit 233 specifies the position in the z direction within the frame of the image corresponding to the fundus surface. A specific example of this process will be described.

  The tomographic image is composed of a plurality of one-dimensional images extending in the depth direction. These one-dimensional images are arranged along the scanning line of the signal light LS. The frame of the tomographic image is black (luminance value 0), and the pixel corresponding to the fundus tissue (layer) has a luminance value corresponding to the intensity of the reflected light at that site. A portion having a depth that does not reach the signal light LS is expressed in black. That is, the tomographic image is an image in which various layers of the fundus are expressed in gray scale in a black frame. The tomographic image may be a pseudo color image corresponding to the luminance value.

  First, the image position determination unit 233 specifies a pixel corresponding to the fundus surface based on the luminance value of the pixel constituting each one-dimensional image. Thereby, the pixel group arranged along the scanning direction of the signal light LS is specified. This pixel group is an image area corresponding to the fundus surface. The specific target is not limited to the fundus surface, and may be a high-luminance part such as IS / OS.

  Subsequently, the image position determination unit 233 determines whether the specified pixel group is within an allowable range in the z direction. This allowable range is set in advance. When the pixel group is within the allowable range, the image position determination unit 233 determines that the depth position of the tomographic image in the frame is appropriate. On the other hand, when the pixel group is not within the allowable range, the image position determination unit 233 determines that the depth position of the tomographic image in the frame is not appropriate.

  Further, the upper end region (image region corresponding to the fundus surface) and the lower end region (image region corresponding to the latest arrival depth of the signal light LS) of the tomographic image are included in the frame, that is, the upper end region and the lower end region are included. You may make it perform the position determination of a tomogram so that it may not cut | disconnect from a flame | frame. For this purpose, for example, in each one-dimensional image, it is determined whether or not the luminance values of the upper and lower vicinity regions of the frame are 0, and further whether or not there is a pixel group whose luminance value is not 0. What should I do?

  The image quality determination unit 234 analyzes the tomographic image of the fundus oculi Ef and determines whether the image quality of the tomographic image is appropriate. There are various image quality evaluation methods. An example will be described below.

  First, the image quality determination unit 234 specifies the pixel with the maximum luminance and the pixel with the minimum luminance for each one-dimensional image in the depth direction that forms the tomographic image. Next, the image quality determination unit 234 creates a luminance value histogram (for example, 8 bits) based on the luminance value of a predetermined range of pixel groups (for example, 40 pixels before and after) including each identified pixel.

  Subsequently, the image quality determination unit 234 searches for the maximum position (luminance value) where the frequency value exceeds 0 in the histogram corresponding to the pixel group including the pixel having the minimum luminance. Further, in the histogram corresponding to the pixel group including the pixel having the maximum luminance, the total number of pixels (N) included in the range equal to or less than the luminance value searched above and the 255th luminance value from the top above the searched luminance value. And the total number of pixels (S) included in. Then, the image quality determination unit 234 evaluates the percentage of the portion that can be regarded as a signal (that is, the portion that can be regarded as not noise) in the tomographic image by the following arithmetic expression: 100 × S ÷ (S + N) . Such calculation processing is executed for each one-dimensional image, and an average value of these calculation results is used as an evaluation value of image quality.

  The image quality determination unit 234 determines whether the evaluation value thus obtained is equal to or greater than a predetermined threshold value. This threshold is set in advance. When it is determined that the evaluation value is equal to or greater than the threshold value, the image quality determination unit 234 determines that the image quality is appropriate. On the other hand, when it is determined that the evaluation value is less than the threshold value, the image quality determination unit 234 determines that the image quality is not appropriate.

  The tracking determination unit 235 determines whether the tracking state is appropriate or not when tracking (following) the irradiation position of the signal light LS with respect to the attention area (OCT image acquisition target area) of the fundus oculi Ef. That is, the tracking determination unit 235 determines whether or not tracking of the irradiation position of the signal light LS is appropriately executed for the eye movement of the eye E or the like.

  The tracking can be executed by controlling the galvanometer mirror in the scanning unit 141. For example, when tracking is performed based on the fundus image (moving image), the position of the fundus characteristic part (optic nerve head, etc.) in each frame of the moving image is specified, and this specified position is always the same position (frame center region, etc.) The irradiation position of the signal light LS is controlled so as to be disposed at the position.

  In addition, when tracking is performed based on an OCT image, a predetermined scanning pattern (for example, a cross scan) is repeatedly applied, and based on a feature shape (for example, a concave shape of a macular) depicted by a pair of sequentially obtained tomographic images, The irradiation position of the signal light LS is controlled so that the feature points (for example, the macular center) are always arranged at the same position (frame center region or the like).

  Note that when performing OCT measurement, tracking based on the OCT image is desirably performed because tracking using the fundus image may be insufficient. In addition, in the fundus image, it is difficult to specify the position of the macula as compared with the optic disc, and therefore it is desirable to perform tracking using the OCT image particularly when acquiring an OCT image of the macula.

  The target site for OCT measurement is set by selecting an internal fixation target (macular, optic nerve head, etc.). For example, the tracking determination unit 235 determines whether or not the tracking state is appropriate by determining whether or not the tracking target part is included in the scanning region of the signal light LS.

  The scanning area is set to a predetermined area (such as a 6 mm × 6 mm square area) centered on the optical axis of the photographing optical system 120, for example. Further, the position of the tracking target part can be obtained with high accuracy by tracking using the above-described OCT image, for example.

  The signal light LS is applied to the eye E along the same optical axis (optical axis of the imaging optical system 120) as illumination light for fundus photography, and the fundus reflection light is also guided along the optical axis. By setting the scanning region of the light LS around the optical axis, the frame center of the fundus image coincides with the center position of the scanning region. By using this, an image representing the position of the scanning region and an image representing the position of the tracking target part can be displayed on the fundus image (described later).

  The image processing unit 230 having the above configuration includes, for example, a microprocessor, a RAM, a ROM, a hard disk drive, and the like. Further, a circuit board that specializes in predetermined image processing and analysis processing may be included.

(Display section, operation section)
The display unit 240 includes the touch panel monitor 11. Furthermore, a display of the arithmetic and control unit 200 may be included in the display unit 240. The display unit 240 is an example of the “display unit” in the present invention. The operation unit 250 includes an input device and an operation device such as a keyboard and a mouse. The operation unit 250 includes various input devices and operation devices provided on the surface of the housing of the optical image measurement device 1 or on the outside.

  The display unit 240 and the operation unit 250 do not need to be configured as individual devices. For example, a device in which the display unit 240 and the operation unit 250 are integrated, such as a touch panel LCD, can be used.

[Scanning signal light and OCT images]
Here, the scanning of the signal light LS and the OCT image will be described.

  Examples of the scanning mode of the signal light LS by the optical image measuring device 1 include horizontal scanning, vertical scanning, cross scanning, radiation scanning, circular scanning, concentric scanning, and helical scanning. These scanning modes are selectively used as appropriate in consideration of the observation site of the fundus, the analysis target (such as retinal thickness), the time required for scanning, the precision of scanning, and the like.

  The horizontal scan scans the signal light LS in the horizontal direction (x direction). The horizontal scan also includes an aspect in which the signal light LS is scanned along a plurality of horizontal scanning lines arranged in the vertical direction (y direction). In this aspect, it is possible to arbitrarily set the scanning line interval. By sufficiently narrowing the interval between the scanning lines, the above-described three-dimensional image can be formed (three-dimensional scan). The same applies to the vertical scan.

  In the cross scan, the signal light LS is scanned along a cross-shaped trajectory composed of two linear trajectories (straight trajectories) orthogonal to each other. In the radiation scan, the signal light LS is scanned along a radial trajectory composed of a plurality of linear trajectories arranged at a predetermined angle. The cross scan is an example of a radiation scan.

  In the circle scan, the signal light LS is scanned along a circular locus. In the concentric scan, the signal light LS is scanned along a plurality of circular trajectories arranged concentrically around a predetermined center position. A circle scan is considered a special case of a concentric scan. The spiral scan scans the signal light LS along a spiral trajectory.

  The scanning unit 141 can scan the signal light LS independently in the x direction and the y direction, respectively, by the configuration as described above. Therefore, the scanning unit 141 can scan the signal light LS along an arbitrary locus on the xy plane. . Thereby, various scanning modes as described above can be realized.

  By scanning the signal light LS in the manner as described above, a one-dimensional image extending in the depth direction is obtained at each scanning point (irradiation position), and these one-dimensional images are arranged along scanning lines (scanning trajectories). By doing so, it is possible to form a two-dimensional tomographic image extending in the scanning line direction and the depth direction (z direction). In particular, when the interval between scanning lines is narrow, the above-described three-dimensional image can be formed.

[Operation]
The operation of the optical image measurement device 1 will be described. The flowcharts shown in FIGS. 6 and 7 represent an example of the operation of the optical image measurement device 1. 8 to 15 show examples of display screens.

  First, as in normal fundus photography, preparation for examination is performed as follows (S1). The face of the subject is brought into contact with the chin rest and the forehead, and the eye E is opposed to the fundus camera unit 1A.

  Control unit 210 displays a predetermined display screen (for example, display screen 290 shown in FIG. 8) on display unit 240 (touch panel monitor 11) in response to a predetermined operation (for example, power-on operation) (S2). The display screen 290 includes an adjustment screen 300 and an interference image display screen 400. The adjustment screen 300 is the same as that shown in FIG. 4 and is used for alignment adjustment and focus adjustment. Although illustration is omitted, an image captured by the fundus camera unit 1A is displayed on the adjustment screen 300. Also, in FIGS. 8 to 12 and 15, information unnecessary for the following explanation is omitted from the information shown in FIG. 4. Although an interference image is displayed on the interference image display screen 400 (described later), the display state at this stage is, for example, a “sandstorm” state.

  The examiner operates the operation unit 250 to turn on the observation light source 101. Thereby, the anterior segment image of the eye E is displayed on the adjustment screen 300. The examiner operates the operation unit 250 (control lever) to move the fundus camera unit 1A to the subject side. At this time, the display image on the adjustment screen 300 is switched to a fundus observation image.

  The control unit 210 turns on the alignment light source 190a in response to a predetermined operation. Thereby, the alignment bright spot is projected onto the eye E, and the alignment bright spot 310 is displayed on the adjustment screen 300 as shown in FIG. 9 (S3). At this stage, since the alignment state is generally inappropriate, two alignment bright spots 310 are displayed outside the alignment scale 309.

  The examiner operates the control lever to adjust the position of the fundus camera unit 1A so as to move the two alignment bright spots 310 to the inside of the alignment scale 309 (S4). FIG. 10 shows an adjustment screen 300 in a state where the alignment adjustment is completed. Instead of manually adjusting the alignment as described above, it is also possible to execute auto alignment as described above.

  When alignment adjustment is completed, focus adjustment is performed. For this purpose, the control unit 210 turns on the LED 109a. Thereby, the split bright line is projected onto the eye E, and the split bright line 311 is displayed on the adjustment screen 300 as shown in FIG. 11 (S5). At this stage, since the focus state is generally inappropriate, the upper and lower split bright lines 311 are not aligned. The controller 210 performs autofocus in the manner described above (S6). The focus determination unit 232 determines whether or not the focus state by the autofocus is appropriate (S7).

  When it is determined that the focus state is not appropriate, that is, when the autofocus has failed (S7: No), the control unit 210 causes the display unit 240 to display predetermined warning information (S8). This warning information informs, for example, that the autofocus has failed or that the examination is urged again. The warning information may be character string information or image information. An example of string information is the following message: "Autofocus failed. Pull the control lever again and try again." The examiner who recognizes the failure of the autofocus based on the warning information restarts the examination from the beginning. If “No” in step 7 occurs a predetermined number of times, the inspection may be terminated.

  When the autofocus is successful (S7: Yes), the upper and lower split bright lines 311 displayed on the adjustment screen 300 are arranged on a straight line as shown in FIG. The alignment determination unit 231 determines the suitability of the alignment state based on the position of the alignment bright spot 310 at this stage (S9).

  When it is determined that the alignment state is not appropriate (S9: No), the control unit 210 causes the display unit 240 to display predetermined warning information (S10). This warning information informs, for example, that the alignment has been shifted or that the alignment is urged again. The warning information may be character string information or image information. An example of string information is the following message: “Match the alignment bright spots and put them in the scale.” The examiner who recognizes that the alignment state is not appropriate based on the warning information returns to step 4 and performs the alignment again. When “No” in step 9 occurs a predetermined number of times, the inspection may be terminated or the inspection may be restarted from the beginning.

  When it is determined that the alignment state is appropriate (S9: Yes), the control unit 210 controls the OCT unit 150, the scanning unit 141, and the image forming unit 220 to automatically perform an interference image (tomographic image) of the fundus oculi Ef. Detection is performed (S11). Automatic detection can be performed by analyzing a detection signal obtained while moving the reference mirror 174, for example. Alternatively, automatic detection may be performed by actually forming an interference image and analyzing the luminance value of the interference image.

  When the automatic detection fails (S12: No), the control unit 210 causes the display unit 240 to display predetermined warning information (S13). This warning information notifies, for example, that an interference image is not detected or that automatic detection is urged again. The warning information may be character string information or image information. An example of character string information is the following message: "Interference image automatic detection failed. Please try again." The examiner who recognizes that the automatic detection has failed due to the warning information performs a predetermined operation (for example, touches the screen of the touch panel monitor 11) and instructs to redo the automatic detection of the interference image. If “No” in step 12 occurs a predetermined number of times, the inspection may be terminated or the inspection may be repeated from the beginning.

  When the automatic detection is successful (S12: Yes), an interference image of the fundus oculi Ef is drawn somewhere in the frame. The interference image is displayed on the image display unit 401 of the interference image display screen 400. The interference image at this stage is displayed at a position where a part thereof protrudes from the interference image display screen 400 as shown in FIG.

  The image quality determination unit 234 determines whether or not the image quality of the detected interference image is appropriate (S14). When it is determined that the image quality is not appropriate (S14: No), the control unit 210 controls the rotation of the polarizing plate 175 to increase the image quality level (S15). At this time, it is desirable to control the polarizing plate 175 so that the image quality level is maximized.

  The image quality level is presented on the image quality display unit 402 of the interference image display screen 400. The image quality display unit 402 is an indicator that presents an evaluation value of image quality. Note that the evaluation value may be displayed as it is.

  When it is determined that the image quality level is appropriate (S14: Yes), the image position determination unit 233 determines whether the position of the interference image in the frame is appropriate (S16).

  As shown in FIG. 13, when a part of the interference image G is cut off from the frame, or when the interference image G is too close to the upper end region or the lower end region of the frame, the position of the interference image G is not appropriate. Determined. At this time, warning information indicating that may be displayed.

  When it is determined that the position of the interference image G is not appropriate (S16: No), the examiner designates a desirable display position of the interference image G in the frame (S17). This operation is performed, for example, by touching a desired position on the image display unit 401 (touch panel monitor 11). A preset position (for example, the center position of the image display unit 401) may be automatically designated.

  The control unit 210 obtains the displacement between the actual position of the interference image G (for example, the position of the macular center) and the designated position. Then, the control unit 210 controls the reference mirror 174 and the scanning unit 141 so as to cancel this displacement, that is, so that the interference image G is displayed at the designated position. Thereby, as shown in FIG. 14, the interference image G is displayed at a suitable position in the frame (S18).

  The displacement of the interference image G in the z direction can be canceled by adjusting the position of the reference mirror 174. Further, the displacement of the interference image G in the x direction and the y direction can be canceled by adjusting the scanning position of the signal light LS by the scanning unit 141.

  When it is determined that the position of the interference image G is appropriate (S16: Yes), or when the interference image G is corrected (S18), the attention site of the fundus oculi Ef is tracked. At this time, although illustration is omitted, a fundus observation image is displayed on the adjustment screen 300. As shown in FIG. 15, the control unit 210 displays the scanning region image 314 and the tracking region image 315 so as to overlap the fundus observation image (S19). Then, the control unit 210 controls the scanning unit 141 and the like to start tracking (S20).

  Note that the scanning region image 314 represents a region where the signal light LS is scanned, and is displayed according to a previously designated mode. A scanning region image 314 shown in FIG. 15 corresponds to the above-described three-dimensional scan. The tracking area image 315 represents a characteristic part of the fundus oculi Ef to be tracked, and moves on the adjustment screen according to the tracking situation. Tracking is performed so that the tracking area image 315 is positioned at the center of the scanning area image 314.

  The tracking determination unit 235 determines whether the tracking state is appropriate (S21). This processing is performed by determining whether or not the tracking area image 315 is included in the scanning area image 314, for example. Note that it may be determined whether the tracking area image 315 is included in a predetermined area (area near the center) in the scanning area image 314.

  When it is determined that the tracking state is not appropriate (S21: No), the control unit 210 causes the display unit 240 to display predetermined warning information (S22). This warning information informs that tracking cannot be suitably performed, for example. The warning information may be character string information or image information. An example of string information is the following message: “Tracking position is out of scanable range”. The examiner who recognizes that the tracking state is not appropriate based on the warning information operates the operation unit 250 (for example, a fixation position adjustment key), and fixes the eye E to be examined so that the tracking area image 315 enters the scanning area image 314. The viewing position is adjusted (S23). At this time, the tracking determination unit 235 determines whether the tracking state is appropriate.

  When it is determined that the tracking state is appropriate (S21: Yes), or when the fixation position adjustment is completed (S23), the image processing unit 230 performs the alignment state, the focus state, and the position of the interference image in the frame. , And the suitability of the image quality of the interference image are determined (S24).

  When it is determined that any of the conditions is not appropriate (S24: No), the same processing as when the condition is determined to be inappropriate is performed (S8, S10, S15, S17).

  When it is determined that all the conditions are appropriate (S24: Yes), the control unit 210 controls the OCT unit 150, the scanning unit 141, and the image forming unit 220 to form an interference image of the scanning region (S25). ). Instead of automatically starting measurement (auto-shoot) in this way, a message indicating that measurement is possible may be displayed. In this case, the examiner who has seen the message presses the photographing switch to start measurement.

  After acquiring the interference image, for example, the control unit 210 controls the fundus camera unit 1A to perform color photographing of the fundus oculi Ef. The acquired interference image and color fundus image are stored in the storage unit 212. This completes the inspection.

[Action / Effect]
The operation and effect of the optical image measurement apparatus 1 as described above will be described.

  The optical image measurement device 1 has a function of acquiring a tomographic image and a fundus image of the fundus (object to be measured). The fundus image is a two-dimensional image of the fundus on a plane substantially orthogonal to the traveling direction of the signal light LS with respect to the fundus.

  The optical image measurement device 1 has an alignment function, a focus function, and a tracking function. The alignment function is realized by alignment means including the alignment optical system 190A. The focus function is realized by focusing means including a focusing optical system. The tracking function is realized by tracking means including the control unit 210. The tracking can be performed based on a tomographic image or can be performed based on a fundus image. The configuration for acquiring a fundus image (configuration as a fundus camera) is an example of the “imaging unit” of the present invention.

  Furthermore, the optical image measurement device 1 determines whether each of the alignment state, the focus state, the position of the tomographic image in the frame, the image quality of the tomographic image, and the tracking state is appropriate, and it is determined that all these conditions are appropriate. The final tomographic image can be acquired. Note that the tomographic image used for determining the suitability of the conditions is acquired in advance, and it is desirable to use a simple scanning mode of the signal light LS (cross scanning in the above embodiment). Further, the distribution of scanning points (irradiation positions of the signal light LS) may not be so dense. On the other hand, the final tomographic image is a precise one used for diagnosis and the like, and it is desirable that the distribution of scanning points is dense (for example, a distribution that can generate a three-dimensional image).

  According to such an optical image measurement device 1, even when a tomographic image of a measured object such as a living eye is acquired, the timing at which the above various conditions are appropriate, that is, the measurement timing is missed. Measurement can be easily performed without any problem.

  Furthermore, in the above-described embodiment, the measurement is automatically performed at appropriate timing according to the various conditions, so that the measurement timing is not missed.

  Further, the optical image measurement device 1 can display warning information when any of the various conditions described above is not appropriate. Thereby, the examiner can recognize that the condition is not appropriate, and can take measures to make the condition appropriate.

[Modification]
The configuration described above is merely an example for favorably implementing the present invention. Therefore, arbitrary modifications within the scope of the present invention can be made as appropriate.

  For example, in the above embodiment, the suitability of the alignment state, the focus state, the position of the tomographic image in the frame, the image quality of the tomographic image, and the tracking state is determined. This determination can be omitted.

  In the present invention, it is determined whether or not the alignment state, the focus state, and the position of the tomographic image in the frame are appropriate. This is because these three conditions are essential for obtaining a suitable tomographic image. In this case, the optical image measurement device determines whether each of the alignment state, the focus state, and the position of the tomographic image in the frame is appropriate, and when all these conditions are determined to be appropriate, the final tomographic image is determined. Allows acquisition of images. Further, similarly to the above-described embodiment, it is possible to automatically perform measurement for obtaining a final tomographic image when it is determined that all conditions are appropriate.

  Further, in addition to the above-described essential condition determination process, the tomographic image quality determination process or tracking state determination process may be performed. These incidental conditions can be added as appropriate in consideration of the type (dynamics) of the object to be measured.

  When it is determined that any of the above-described various conditions is not appropriate, acquisition of a tomographic image of the object to be measured can be prohibited. As a specific example, even if it is determined that a certain condition is inappropriate, even if the examiner gives a tomographic image acquisition instruction (such as pressing an imaging switch), the control unit 210 does not accept this instruction (ignore). Can be configured.

  In the above embodiment, the position of the reference mirror 174 is changed to change the optical path length difference between the optical path of the signal light LS and the optical path of the reference light LR. However, the method of changing the optical path length difference is limited to this. Is not to be done. For example, the optical path length difference can be changed by moving the fundus camera unit 1A and the OCT unit 150 integrally with the eye E to change the optical path length of the signal light LS. In particular, when the measured object is not a living body, the optical path length difference can be changed by moving the measured object in the depth direction (z direction).

  The computer program in the above embodiment can be stored in any recording medium that can be read by the drive device of the computer. As this recording medium, for example, an optical disk, a magneto-optical disk (CD-ROM / DVD-RAM / DVD-ROM / MO, etc.), a magnetic storage medium (hard disk / floppy (registered trademark) disk / ZIP, etc.), etc. are used. Is possible. It can also be stored in a storage device such as a hard disk drive or memory. Furthermore, this program can be transmitted and received through a network such as the Internet or a LAN.

1 Optical Image Measuring Device 1A Fundus Camera Unit 100 Illumination Optical System 120 Imaging Optical System 141 Scanning Unit 150 OCT Unit 160 Low Coherence Light Source 174 Reference Mirror 180 Spectrometer 184 CCD
190A alignment optical system 200 arithmetic control device 210 control unit 220 image forming unit 230 image processing unit 231 alignment determination unit 232 focus determination unit 233 image position determination unit 234 image quality determination unit 235 tracking determination unit 240 display unit 250 operation unit 309 alignment scale 310 alignment bright spot 311 split bright line

Claims (3)

The light from the light source is divided into signal light and reference light, and the interference light is generated by causing the signal light passing through the object to be measured and the reference light passing through the reference object to interfere with each other to detect the interference light An optical system for generating a detection signal by
Image forming means for forming an image of the object to be measured based on the detection signal;
An optical image measuring device having
Alignment means for aligning the optical system with respect to the object to be measured;
Focusing means for focusing the optical system on the object to be measured;
Image position determining means for determining the position of the image in a predetermined frame based on the detection signal;
Determine the suitability of the position of the optical system and the suitability of the focus state, determine the suitability of the position of the image in the predetermined frame, determine the suitability of the position of the optical system, and determine the suitability of the focus state And after all the determination of the propriety of the position of the image is completed, a determination unit that performs all the determination of propriety again,
When it is determined that the position of the optical system, the focused state, and the position of the image are all appropriate in the second suitability determination, the optical system and the image forming unit are controlled to control the object. Control means enabling acquisition of an image of the measurement object;
An optical image measurement device comprising: The determination means determines the position of the image so that an upper end region and a lower end region of the image of the object to be measured are arranged in the frame;
The optical image measuring device according to claim 1. An optical system for acquiring an image of the eye to be examined;
Alignment means for aligning the optical system with respect to the eye to be examined;
Focusing means for focusing the optical system on the eye to be examined;
Image position determination means for determining the position of the image of the subject's eye within a predetermined frame after the image of the subject's eye is preliminarily acquired using the optical system;
Determining the suitability of the position of the optical system and the suitability of the in-focus state; determining the suitability of the position of the image of the subject eye within the predetermined frame; determining the suitability of the position of the optical system; After all the determination of suitability and the judgment of suitability of the position of the image of the eye to be examined are completed, a determination means for performing all these suitability determinations again,
When it is determined that the position of the optical system, the in-focus state, and the position of the image of the eye to be examined are all appropriate in the second suitability determination, the optical system is controlled to control the eye of the eye to be examined. Control means for enabling image acquisition;
An imaging apparatus comprising:

Images