WO2010119633A1 - Optical image measuring device and method for controlling same - Google Patents

Abstract

Disclosed is an optical image measuring device which enables detection of interference light and formation of a tomogram in parallel with each other. The device is provided with a control unit (210) for scanning the eye (E) to be examined with a signal light beam while changing the directions of galvanometer mirrors (141A, 141B), an OCT unit (150) for detecting interference light, an image forming unit (220) for forming a tomogram of the eye (E) to be e examined, and an abnormality detecting unit(250) for detecting an abnormality of the tomogram, if any, on the basis of the image state of the formed tomogram. The abnormality detecting unit (250) performs abnormality detection each time a predetermined number of frames of the tomogram are obtained. If an abnormality is detected, the control unit (210) stops the change of the directions of the galvanometer mirrors (141A, 141B), and the OCT unit (150) resumes the detection of interference light from the state in which the directions are the ones when the change is stopped.

Description

Optical image measuring device and control method thereof

The present invention relates to an optical image measuring apparatus that scans a measured object with a light beam and forms an image of the measured object using interference of reflected light, and a control method thereof.

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

Patent Document 1 discloses an apparatus to which an optical image measurement technique is applied. In this apparatus, the measuring arm scans an object with a rotating turning mirror (galvanomirror), a reference mirror is installed on the reference arm, and light that appears due to interference of light beams from the measuring arm and the reference arm at the exit. An interferometer in which the intensity of the light is analyzed by a spectroscope is used, and the reference arm is provided with a device for changing the phase of the reference light beam stepwise by a discontinuous value.

The optical image measuring apparatus of Patent Document 1 uses a so-called “Fourier Domain OCT (Fourier Domain Optical Coherence Tomography)” technique. That is, by irradiating the measured object with a beam of low coherence light, obtaining the spectral intensity distribution of the interference light between the reflected light and the reference light, and performing Fourier transform on the spectral intensity distribution, the depth direction (z Direction) is imaged.

Furthermore, the optical image measurement device 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. In this optical image measuring device, since the light beam is scanned only in one direction (x direction) orthogonal to the depth direction (z direction), the image to be formed is in the scanning direction of the light beam ( It becomes a two-dimensional tomographic image in the depth direction along (x direction).

In Patent Document 2, a plurality of two-dimensional tomographic images in the scanning direction (x direction) are scanned by scanning the signal light in the scanning direction (x direction) and the vertical direction (y direction: a direction orthogonal to the x direction and the z direction). A technique for forming and obtaining three-dimensional tomographic information of a measurement range based on the plurality of tomographic images and imaging it is disclosed. As this three-dimensional imaging, for example, a method of displaying a plurality of tomographic images side by side in the vertical direction (y direction) (called stack data or the like), or rendering a plurality of tomographic images to form a three-dimensional image Possible ways to do this.

Patent Documents 3 and 4 disclose other types of optical image measurement devices. Patent Document 3 scans the wavelength of light irradiated to an object to be measured, acquires a spectral intensity distribution based on interference light obtained by superimposing reflected light and irradiated light of each wavelength, 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.

Japanese Patent Laid-Open No. 11-325849 JP 2002-139421 A JP 2007-24677 A JP 2006-153838 A

However, in the conventional optical image measurement devices as described in Patent Documents 1 to 4, detection of interference light for all the required number of frames was performed in order to create a three-dimensional image. Later {for example, after capturing all the B-scan interference spectrum (128 frames if 128 frames)}, image processing such as Fourier transform is performed on the detection results. It was. As described above, since the interference light detection and image formation for the required number of frames are sequentially performed, the next processing stage (image formation) is performed until the previous processing stage (interference light detection) is completed. Could not be implemented. Therefore, conventionally, it takes a long processing time to generate a three-dimensional image. In addition, since each stage is performed sequentially, it is difficult to effectively use the resources of the apparatus.

Conventionally, after detecting interference light in all frames, a tomographic image corresponding to all frames is formed, and thereafter, abnormality detection is performed. For this reason, when an abnormality occurs in the tomographic image, the measurement of the object to be measured has to be performed again from the beginning.

The present invention has been made in view of such circumstances, and an object of the present invention is to reduce the processing time for 3D image formation by performing image formation without waiting for completion of detection of interference light corresponding to all frames. An object of the present invention is to provide an optical image measurement device that can be shortened.

In order to achieve the above object, an optical image measurement device according to claim 1 divides low-coherence light into signal light and reference light, changes the direction of a galvanometer mirror, and irradiates the object to be measured with the signal light. Scanning the signal light with respect to the object to be measured while changing the position, irradiating the signal light to the object to be measured and reflecting the signal light reflected by the object to be measured and the reference light via the reference light path To generate interference light, and form a tomographic image of the object to be measured from the interference light detection means for detecting the interference light and the detection result obtained by scanning one frame by the interference light detection means And a tomographic image forming means for detecting an abnormality of the tomographic image based on an image state of the formed tomographic image, wherein the tomographic image forming means has one frame by the interference light detecting means. The tomographic image is sequentially formed every time the interference light detection results for the predetermined number of frames are obtained, and the abnormality detecting means performs the abnormality detection every time the tomographic image for a predetermined frame is obtained, and the abnormality is detected. Then, the interference light detection means stops changing the direction of the galvanometer mirror, and restarts the detection of the interference light from the stopped direction.

A second aspect of the present invention is the optical image measurement device according to the first aspect, wherein the abnormality detecting means detects an abnormality based on a position of the measured object depicted in the tomographic image. It is characterized by this.

The optical image measurement apparatus according to claim 3, wherein the low-coherence light is divided into signal light and reference light, the orientation of the galvano mirror is changed, and the irradiation position of the signal light on the object to be measured is changed. The signal light is irradiated onto the object to be measured while scanning the signal light with respect to the object, and the signal light reflected by the object to be measured and the reference light passing through a reference light path are superimposed to generate interference light. Interference light detecting means for generating and detecting the interference light, and tomographic image forming means for forming a tomographic image of the measured object from a detection result obtained by scanning one frame by the interference light detecting means, The interference light detection means detects the interference light while sequentially changing the direction of the galvanometer mirror, and the tomographic image formation means is based on the interference light detection means. In parallel with the detection of serial interference light, effect formation of a tomographic image for each of the one frame of the detection result is obtained, it is characterized in.

The invention according to claim 4 is the optical image measurement device according to claim 3, further comprising an abnormality detection means for detecting an abnormality of the tomographic image based on an image state of the formed tomographic image. The interference light detection means stops detecting the interference light when the abnormality is detected.

The invention according to claim 5 is the optical image measurement device according to claim 4, wherein the abnormality detection means performs abnormality detection based on the position of the eye to be examined depicted in the tomographic image. It is characterized by.

The invention according to claim 6 is the optical image measurement device according to claim 4, wherein the abnormality detection means performs the abnormality detection every predetermined number of frames.

A seventh aspect of the present invention is the optical image measurement device according to the sixth aspect, wherein the abnormality detection unit is configured to detect the predetermined number of frames before and after the frame where the abnormality is detected. The abnormality detection is performed, and the interference light detection unit stops detecting the interference light when at least the predetermined number of frames in which the abnormality is detected continues. .

The invention according to claim 8 is the optical image measuring device according to claim 4, wherein the galvanometer mirror is obtained when the scan corresponding to the tomographic image in which the abnormality is detected is performed. And the interference light detection means changes the direction of the galvano mirror to the determined direction and starts detecting the interference light again from the direction of the galvano mirror when the abnormality is detected. It is characterized by that.

The invention according to claim 9 is the optical image measurement device according to claim 8, wherein the acquisition unit includes the tomographic image at the time when the abnormality is detected from the tomographic image where the abnormality is detected. And obtaining the orientation of the galvanometer mirror in the tomographic image before the acquired number of frames from the frame at the time when the abnormality is detected.

A tenth aspect of the present invention is the optical image measurement device according to the eighth aspect, wherein the object to be measured is a fundus and a fundus image is detected during detection of interference light by the interference light detection means. The imaging device further includes an imaging unit that acquires at a rate, and the acquisition unit detects the abnormality based on the fundus image at the time of detecting the interference light of the tomographic image in which the abnormality is detected. Obtaining a position of the tomographic image in the fundus image, specifying a position corresponding to the acquired position in the current fundus image, and obtaining an orientation of the galvanometer mirror so as to scan the specified position; It is characterized by this.

The control method of the optical image measurement device according to claim 11, wherein the low-coherence light is divided into signal light and reference light, the direction of the galvanometer mirror is changed, and the irradiation position of the signal light on the object to be measured is changed. The signal light is irradiated onto the object to be measured while scanning the signal light with respect to the object to be measured, and the signal light reflected by the object to be measured and the reference light passing through a reference light path are superimposed. Interference light detection means for generating interference light and detecting the interference light, and tomographic image formation means for forming a tomographic image of the object to be measured from a detection result obtained by scanning one frame by the interference light detection means And an abnormality detection means for detecting an abnormality of the tomographic image based on an image state of the formed tomographic image, wherein the detecting step detects the interference light. When, A tomographic image forming step for forming the tomographic image in units of frames, an abnormality detecting step for detecting the abnormality every time the tomographic image for a predetermined frame is obtained, and when the abnormality is detected, The method includes a galvano mirror stop stage for stopping driving of the galvano mirror, and a stage for restarting the detection stage from the orientation of the stopped galvano mirror.

The control method of the optical image measurement device according to claim 12, wherein the low-coherence light is divided into signal light and reference light, the direction of the galvanometer mirror is changed, and the irradiation position of the signal light on the object to be measured is changed. The signal light is irradiated onto the object to be measured while scanning the signal light with respect to the object to be measured, and the signal light reflected by the object to be measured and the reference light passing through a reference light path are superimposed. Interference light detection means for generating interference light and detecting the interference light, and tomographic image formation means for forming a tomographic image of the object to be measured from a detection result obtained by scanning one frame by the interference light detection means A method of controlling the optical image measurement apparatus comprising: an interference light detection stage that sequentially detects the interference light while changing the direction of the galvanometer mirror; and one frame in the interference light detection stage. A tomographic image forming step of forming the tomographic image every time a detection result for a predetermined number of times is obtained, wherein the interference light detecting step performs the detection continuously, and the image forming step detects the interference light It is performed in parallel with the stage.

According to the present invention, it is possible to detect an abnormality in an image during detection of interference light. Thereby, it is possible to detect the occurrence of an abnormal image in parallel with the scanning of the object to be measured. Therefore, the occurrence of an abnormal image can be quickly grasped, and the processing time of the three-dimensional image forming process can be shortened. In addition, the resource of the apparatus can be effectively used.

Further, according to the present invention, detection of interference light and formation of a tomographic image can be performed in parallel. As a result, it is possible to form a tomographic image without waiting for the completion of scanning of all frames of the eye to be examined, and it is possible to effectively utilize the resources of the apparatus and reduce the time required for the process of forming a three-dimensional image. Therefore, it is possible to contribute to shortening the inspection time of the object to be measured.

In addition, according to the present invention, the detection of interference light and the formation of a tomographic image are performed in parallel, and when an abnormality in the tomographic image is detected, the process returns to the place where the abnormal image has occurred and is again covered from that place. The scanning of the measurement object can be resumed. This makes it possible to effectively use the resources of the apparatus and reduce the time required for the 3D image forming process.

It is a schematic structure figure showing an example of the whole composition of the embodiment of the optical image measuring device concerning this invention. It is a schematic block diagram 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 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 the schematic showing an example of the scanning aspect of the signal light by embodiment of the optical image measuring device which concerns on this invention, and represents an example of the scanning aspect of the signal light when the fundus is seen from the incident side of the signal light with respect to the eye to be examined ing. It is the schematic showing an example of the scanning aspect of the signal light by embodiment of the optical image measuring device based on this invention, and represents an example of the arrangement | sequence aspect of the scanning point on each scanning line. It is a flowchart showing an example of the usage pattern of embodiment of the optical image measuring device which concerns on this invention. It is a sequence diagram showing an example of the on / off state of each function part corresponding to the passage of time of the optical image measurement device according to the present invention. It is a flowchart showing an example of the operation | movement in the on / off state of each function part.

[First Embodiment]
Hereinafter, an optical image measurement device according to a first embodiment of the present invention will be described. In the following embodiment, a configuration to which a Fourier domain type technique is applied will be described in detail. 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. Further, 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.

[Device configuration]
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 distributed manner 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. 2). 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 1A, and displays various information such as tomographic images, patient information, and imaging conditions acquired by the optical image measurement device 1. 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 the case of 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 wavelengths in the near-infrared region, for example, in the range of about 700 nm to 800 nm. 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 a wavelength 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 reaches the perforated mirror 112 via the condenser lenses 102 and 104, the (exciter filter 105 or 106) ring translucent plate 107, the mirror 108, the illumination stop 110, and the relay lens 111. To do. 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 the fundus reflection light (having a wavelength included in the range of about 400 nm to 800 nm) of the 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. 2) 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.

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.

The fixation direction of the eye E can be changed by changing the display position of the internal fixation target on the LCD 140. As the fixation direction of the eye E, for example, a fixation direction for acquiring a tomographic image centered on the macular region of the fundus oculi Ef or a tomographic image centered on the optic disc as in the case of a conventional fundus camera. A fixation direction for obtaining a tomographic image centered on the fundus center between the macula and the optic disc, and the like. 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 the 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 141A for scanning in the x direction and a galvanometer mirror 141B for scanning in the y direction (see FIG. 3).

[Configuration of 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 the 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, a PM fiber (Polarization maintaining fiber), or the like. 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 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 and the density filter 173.

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

Note that the glass block 172 and the density filter 173 act 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 acts 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 reference mirror 174 is moved in the traveling direction of the reference light LR (the direction of the double-sided arrow shown in FIG. 2) 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 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.

A spectrometer (spectrometer) 180 detects a 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 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.

The “interference light detection means” according to the present invention is disposed, for example, between the scanning unit 141, the optical coupler 162, and an optical member on the optical path of the signal light LS (that is, between the optical coupler 162 and the fundus oculi Ef). Optical member) and an optical member on the optical path of the reference light LR (that is, an optical member disposed between the optical coupler 162 and the reference mirror 174). In particular, the scanning unit 141, the optical coupler 162, It includes an interferometer having optical fibers 163 and 164 and a reference mirror 174, and further has a CCD 184.

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 a display device such as LCD 140, movement control of illumination diaphragm 110 (control of aperture value), control of aperture value of photographing diaphragm 121, control of movement control of focus lens 124 (focus adjustment, magnification adjustment), etc. Do. The arithmetic and control unit 200 controls the operation of the galvanometer mirrors 141A and 141B (see FIG. 3) and 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. In FIG. 3, 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 connected to 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 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.

(Main control unit)
The main controller 211 controls the mirror drive mechanisms 241 and 242 to control the orientation (angle) of the galvano mirrors 141A and 141B. Thereby, the irradiation position of the signal light LS on the fundus oculi Ef is scanned. In addition, the main control unit 211 controls the LCD 140 to display the internal fixation target. In particular, the main control unit 211 controls the mirror driving mechanisms 241 and 242 and the LCD 140 simultaneously to cause the eye E to present the internal fixation target and scan the signal light LS.

(Memory part)
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 a computer program for executing an operation (flow chart) described later. The main control unit 211 operates based on 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. 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 kinds 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 luminance correction and dispersion correction of the tomographic image.

Further, 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 the 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 line-of-sight 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 240A.

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, stack data is image data obtained by expressing a plurality of tomographic images originally defined by individual two-dimensional coordinate systems by one three-dimensional coordinate system (that is, by embedding them 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 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.

The image forming unit 220 (and the image processing unit 230) functions as an example of the “tomographic image forming unit” according to the present invention.

(Abnormality detection unit)
The abnormality detection unit 250 detects whether or not an abnormality has occurred in the tomographic image with respect to the image data of the tomographic image formed by the image forming unit 220. In this embodiment, an abnormality in a tomographic image means that, for example, a portion to be imaged (specifically, fundus oculi Ef) moves from the vicinity of the center of the tomographic image due to the movement of the eye E to be examined. It means that the image is taken toward the upper end or the lower end. Here, the upper end of the tomographic image indicates a shallow position in the depth direction (z direction). The lower end of the tomographic image indicates a deep position in the depth direction (z direction). There is a disadvantage that the resolution is lowered at the upper or lower end of the tomographic image. Therefore, if the part to be imaged is positioned at the end, there is a possibility that accurate diagnosis cannot be performed. For example, the abnormality detection unit 250 grasps the position of the image to be inspected based on the luminance value of each pixel included in the tomographic image. Further, the abnormality detection unit 250 obtains a deviation from the center of the image and compares the deviation with a predetermined threshold value. When it is determined that this deviation is larger than the threshold value, the abnormality detection unit 250 assumes that an abnormality has occurred in the tomographic image. However, the method for obtaining the position of the image is not particularly limited, and other methods may be used. In this embodiment, an abnormality is detected based on the position of the image. However, an abnormality may be detected based on another image state. For example, an abnormality can be detected based on image disturbance due to noise. The abnormality detection unit 250 corresponds to the “abnormality detection unit” in the present invention.

(Display section, operation section)
The user interface 240 includes a display unit 240A and an operation unit 240B. The display unit 240 </ b> A includes the touch panel monitor 11. Furthermore, a display of the arithmetic and control unit 200 may be included in the display unit 240A. The operation unit 240B includes an input device and an operation device such as a keyboard and a mouse. The operation unit 240 </ b> B includes various input devices and operation devices provided on the surface of the housing of the optical image measurement device 1 and on the outside.

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

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

4A and 4B show an example of a scanning mode of the signal light LS for forming a tomographic image of the fundus oculi Ef. 4A shows an example of a scanning mode of the signal light LS when the fundus oculi Ef is viewed from the direction in which the signal light LS enters the eye E (that is, when the + z direction is viewed from the −z direction in FIG. 1). FIG. 4B shows an example of an arrangement mode of scanning points (positions where image measurement is performed) on each scanning line on the fundus oculi Ef.

As shown in FIG. 4A, the signal light LS is scanned in a rectangular scanning region R set in advance. In the scanning region R, a plurality (m) of scanning lines R1 to Rm extending in the x direction are set. When the signal light LS is scanned along each scanning line Ri (i = 1 to m), a detection signal of the interference light LC is generated.

The direction of each scanning line Ri is referred to as the “main scanning direction”, and the direction orthogonal thereto is referred to as the “sub-scanning direction”. Therefore, scanning of the signal light LS in the main scanning direction is executed by changing the direction of the reflecting surface of the galvano mirror 141A. A cross section corresponding to each scanning line Ri corresponds to one frame. Further, scanning in the sub-scanning direction is executed by changing the direction of the reflecting surface of the galvano mirror 141B.

On each scanning line Ri, as shown in FIG. 4B, a plurality (n) of scanning points Ri1 to Rin are set in advance.

4A and 4B, the control unit 210 first controls the galvanometer mirrors 141A and 141B, and sets the incidence target of the signal light LS on the fundus oculi Ef to the scanning start position on the first scanning line R1. Set to RS (scanning point R11). Subsequently, the control unit 210 controls the low coherence light source 160 to cause the low coherence light L0 to flash and cause the signal light LS to enter the scan start position RS. The CCD 184 receives the interference light LC based on the fundus reflection light at the scanning start position RS of the signal light LS and outputs a detection signal to the control unit 210.

Next, the control unit 210 controls the galvanometer mirror 141A, scans the signal light LS in the main scanning direction, sets the incident target at the scanning point R12, flashes the low coherence light L0, and scans the scanning point. The signal light LS is incident on R12. The CCD 184 receives the interference light LC based on the fundus reflection light at the scanning point R12 of the signal light LS, and outputs a detection signal to the control unit 210.

Similarly, the control unit 210 sequentially moves the incident target of the signal light LS to the scanning points R13, R14,..., R1 (n−1), R1n, and flashes the low coherence light L0 at each scanning point. By emitting light, a detection signal output from the CCD 184 corresponding to the interference light LC at each scanning point is acquired. Thereby, the scanning and detection corresponding to the first frame is completed.

Thus, the control unit 210 controls the OCT unit 150 and the galvanometer mirrors 141A and 141B described above, and causes the OCT unit 150 to detect interference light. When the measurement at the last scanning point R1n of the first scanning line R1 ends, the image forming unit 220 forms a tomographic image of the fundus oculi Ef along the scanning line R1 (main scanning direction) (details will be described later). .

Then, the abnormality detection unit 250 detects an abnormality of the tomographic image based on the position of the eye E to be examined (more specifically, the position of the fundus oculi Ef) depicted in the tomographic image formed by the image forming unit 220. That is, the abnormality detection unit 250 determines that an abnormality has occurred in the tomographic image when the fundus oculi Ef is located near the upper end or the lower end of the tomographic image.

When the abnormality detection unit 250 detects an abnormality in the tomographic image, the control unit 210 controls the OCT unit 150 and the galvanometer mirrors 141A and 141B so that the tomographic image of the fundus oculi Ef along the scanning line R1 is formed again.

On the other hand, when the abnormality detection unit 250 does not detect any abnormality in the tomographic image, the control unit 210 performs scanning along the next scanning line R2. That is, the control unit 210 controls the galvanometer mirrors 141A and 141B simultaneously to move the incident target of the signal light LS to the first scanning point R21 of the second scanning line R2. Then, by performing the above-described measurement for each scanning point R2j (j = 1 to n) of the second scanning line R2, a detection signal corresponding to each scanning point R2j is obtained. Further, the arithmetic and control unit 200 causes each unit to perform operations such as generation of a tomographic image on the scanning line R2, detection of abnormality in the tomographic image, redetection of interference light, and re-formation of the tomographic image.

Similarly, measurement is performed for each of the third scanning line R3,..., The m−1th scanning line R (m−1), and the mth scanning line Rm, and detection corresponding to each scanning point is performed. Get the signal. Further, operations such as generation of a tomographic image at each scanning line Ri, detection of abnormality in the tomographic image, redetection of interference light, and re-formation of the tomographic image are performed. The operation on each scanning line Ri corresponds to “every time the tomographic image for a predetermined frame is obtained”. Here, the “predetermined number of frames” is “1 frame”, but may be an arbitrary number of 2 frames or more (for example, “10 frames”). Note that the symbol RE on the scanning line Rm is a scanning end position corresponding to the scanning point Rmn.

Thereby, the control unit 210 acquires m × n detection signals corresponding to m × n scanning points Rij (i = 1 to m, j = 1 to n) in the scanning region R, and Image formation, abnormality detection, and tomographic image reconstruction can be performed. Hereinafter, the detection signal corresponding to the scanning point Rij may be represented as Dij.

When the galvanometer mirrors 141A and 141B are operated as described above, the control unit 210 stores the position of the scanning line Ri and the position of the scanning point Rij (coordinates in the xy coordinate system) as information indicating the operation content. It has become. This stored content (scanning position information) is used in an image forming process or the like as in the prior art.

Next, an example of detecting an abnormality in a tomographic image by the abnormality detection unit 250 will be described. The abnormality detection unit 250 receives a tomographic image input on each scanning line Ri formed by the image forming unit 220. Then, the abnormality detection unit 250 extracts nine images in the depth direction among the images in the depth direction at each of the scanning points Ri1 to Rin constituting the tomographic image. The abnormality detection unit 250 stores in advance the positions of these nine scanning points (that is, what number of scanning points are extracted). In order to detect the occurrence of an abnormality in the tomographic image, the positions of these scanning points are preferably distributed on the average in the tomographic image. For example, 25 × k-th (k = 1, 2,..., 9) scanning points, that is, scanning point Ri25k, such as 25, 50, 75,. Then, the abnormality detection unit 250 obtains the luminance value of each pixel included in the image in the depth direction at these nine scanning points. Further, the abnormality detection unit 250 determines that an image in the depth direction at the scanning point is abnormal when a portion having a high luminance value exists above or below the tomographic image. Then, the abnormality detection unit 250 notifies the control unit 210 that an abnormality has been detected in the tomographic image when abnormality is detected in a predetermined number or more of the images in the depth direction along these nine scanning points. I do. On the other hand, when no abnormality is detected in a predetermined number or more of the images at these nine scanning points, the abnormality detection unit 250 notifies the control unit 210 that the tomographic image is normal. Here, the predetermined number may be any one of 1 to 9. In order to accurately detect the occurrence of an abnormality in the tomographic image, it is preferable to set the predetermined number small.

As described above, in this embodiment, nine scans dispersed on the screen are averaged in order to make the detection accuracy of the tomographic image abnormality constant, reduce the load of the abnormality detection process, and improve the processing speed. An image abnormality is detected using an image in the depth direction at the point, but the number of scanning points used for this processing is preferably determined based on the accuracy of abnormality detection, the processing speed, and the like. For example, if it is desired to improve the processing speed, abnormality detection may be performed using a smaller number of scanning points. If abnormality detection is performed using all scanning points, abnormality detection with higher accuracy can be performed.

[Operation]
The operation of the optical image measurement device 1 will be described. The flowchart shown in FIG. 5 represents an example of a usage pattern of the optical image measurement device 1 according to the present embodiment.

First, the eye E is placed at a predetermined measurement position (a position facing the objective lens 113), and the eye E and the apparatus are aligned (S1). When the alignment is completed, the main control unit 211 next focuses on the eye E (S2).

When the alignment adjustment and focus adjustment are completed, the operator operates the operation unit 240B to request the start of inspection (S3). At this time, the main control unit 211 controls the LCD 140 as necessary to present the internal fixation target to the eye E.

The main control unit 211 having received the request to start the inspection first sets i = 1 (S4).

The main control unit 211 controls the low coherence light source 160, the CCD 184, and the like, and also controls the mirror drive mechanisms 241 and 242 to adjust the direction of the galvanometer mirrors 141A and 141B to the direction of the scanning point Ri1 (S5). . Then, the main control unit 211 sequentially changes the direction of the galvanometer mirrors 141A and 141B from the direction of the scanning point Ri1 to the direction of each scanning point Rij (j = 2 to m), and executes scanning along the scanning line Ri. The interference light LC is detected (S6).

Subsequently, the image forming unit 220 collects detection signals output from the CCD 184, and obtains a spectrum intensity distribution based on the detection signals. Further, the image forming unit 220 images the form in the depth direction (z direction) of the fundus oculi Ef by Fourier transforming the spectral intensity distribution of the interference light LC using a Fourier domain OCT technique, and forms a tomographic image. (S7).

The abnormality detection unit 250 acquires images in the depth direction at nine scanning points from the image data of the tomographic image formed by the image forming unit 220. Further, the abnormality detection unit 250 detects whether or not an abnormality has occurred in the tomographic image by obtaining the luminance values of the pixels included in the nine images in the depth direction (S8).

If no abnormality is detected (No in S8), the main control unit 211 increments by setting i = i + 1 and increases the value of i by 1 (S9). That is, the scan along the scan line Ri shifts from the scan along the scan line R (i + 1). On the other hand, if an abnormality is detected (Yes in S8), the main control unit 211 holds the value of i as it is, stops driving the galvanometer mirrors 141A and 141B, and returns to Step 6 (S10).

Here, when repetition of steps 6, 7, 8, and 10 starts and a loop is entered, although not shown, it is possible to skip step 8 and proceed to step 9 in response to input from the operator. is there. In addition, a step for counting the number of repetitions is provided between step 7 and step 8, and when the number of repetitions reaches a predetermined number, step 8 is skipped and the process proceeds to step 9. Also good.

Further, the main control unit 211 determines whether i> m (where m is the number of all scanning lines) (S11). If i> m (Yes in S11), the process proceeds to Step 12. If i ≦ m (No in S11), the process returns to Step 5.

In step 12, the image processing unit 230 generates a three-dimensional image based on the formed m tomographic images. Then, the control unit 210 causes the display unit 240A to display the three-dimensional image generated by the image processing unit 230 (S12).

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

In one frame, the optical image measuring device 1 forms a tomographic image following the scanning of the eye E while detecting the direction of the galvano mirror while changing the direction of the galvanometer mirror, and detects the interference light. It has the structure which detects sequentially whether it has generate | occur | produced. When the occurrence of an abnormality in a tomographic image is detected, the optical image measurement device 1 can stop changing the orientation of the galvanometer mirrors 141A and 141B in that state, and perform scanning again from the scanning position corresponding to the tomographic image. Have

According to such an optical image measurement device 1, since an abnormality of the tomographic image can be confirmed every frame, the abnormality can be detected quickly. The optical image measurement device 1 is configured to stop changing the orientation of the galvano mirrors 141A and 141B when an abnormality occurs and scan again from that position. Therefore, after all the scanning of the eye E and the image formation are completed, there is no need to search for the position where the abnormality has occurred in order to re-form the tomographic image of the place where the abnormality has occurred. It becomes possible to deal with it quickly.

[Modification 1]
The configuration described above is merely an example for favorably implementing the optical image measurement device according to the present invention. Therefore, arbitrary modifications within the scope of the present invention can be made as appropriate.

In the above embodiment, when an abnormality is detected, scanning is automatically started again from the scanning position corresponding to the tomographic image in which the abnormality has occurred. Scanning may be started manually.

Also in this modification, as in the above embodiment, the abnormality detection unit 250 detects an abnormality in the tomographic image. When the control unit 210 receives the information, the control unit 210 controls the mirror driving mechanisms 241 and 242 to stop driving the galvano mirrors 141A and 141B. Further, the control unit 210 stops the inspection by stopping the operations of the OCT unit 150, the image forming unit 220, and the abnormality detection unit 250 in this state.

Further, in the present modification, for example, the control unit 210 waits for an input from the operation unit 240B by the operator, and in response to the operator issuing an instruction to restart the inspection using the operation unit 240B, the galvanometer mirror 141A and The inspection can be resumed from the stop position 141B.

As described above, the optical image measurement device according to the present modification is configured to stop changing the orientation of the galvanometer mirror and wait for the operator's instruction as it is when a tomographic image abnormality is detected.

By adopting such a configuration, it is possible to restart the inspection according to the operator's request and to adjust the position of the scanning position at the time of the inspection restart, and it is possible to perform an inspection that further meets the operator's request. .

[Modification 2]
In the above embodiment, abnormality detection is performed for each frame (that is, for each tomographic image), but abnormality is performed at a rate of a plurality of frames, for example, for every 10 frames (that is, for every 10 tomographic images). Detection may be performed.

An example of this configuration will be described. The control unit 210 has a counter. This counter counts the number of tomographic images formed. When the counted number reaches ten, the control unit 210 transmits a control command to the abnormality detection unit 250 so that abnormality detection is performed on the tenth tomographic image. When the control unit 210 transmits a command for detecting an abnormality, the control unit 210 resets the counter to 0 and counts 10 sheets again. In this way, the abnormality detection unit 250 receives the control command and performs abnormality detection on every ten tomographic images.

Here, the number of frames for determining the number of frames for which abnormality detection is performed may be a predetermined number or a number determined by receiving an input of the number of frames requested by the operator.

By adopting such a configuration, the abnormality detection is performed every plural frames, and the processing time can be shortened as compared with the case where the abnormality detection is performed every frame.

[Second Embodiment]
A second embodiment of the optical image measurement device according to the present invention will be described. In this embodiment, scanning of an object to be measured, detection of interference light, and image formation are performed in parallel. In this embodiment, scanning of an object to be measured, detection of interference light, control of image formation, and operation will be described.

The control unit 210 controls the mirror drive mechanisms 241 and 242 to change the orientation of the galvanometer mirrors 141A and 141B, while causing the OCT unit 150 to follow the scanning line Ri (i = 1, 2,... M). Scanning of the fundus oculi Ef and detection of interference light are sequentially performed. This differs from the first embodiment in that scanning and detection in each frame corresponding to the scanning lines R1 to Rm are performed in parallel with image formation and abnormality detection.

More specifically, the control unit 210 causes the OCT unit 150 to sequentially detect the interference light based on the scanning along each of the scanning lines R1 to Rm. Further, the control unit 210 causes the image forming unit 220 to sequentially form tomographic images (acquisition of spectrum intensity distribution, Fourier transform, etc.) based on detection results corresponding to the scanning lines R1 to Rm. Here, the control unit 210 causes the detection of the interference light by the OCT unit 150 and the formation of the tomographic image by the image forming unit 220 to be executed independently of each other.

The operation of measuring the fundus oculi Ef using the optical image measurement device 1 having the above configuration will be described. The sequence diagram shown in FIG. 6 is an example of an on / off state (a state of whether or not the functional unit is operating) corresponding to the passage of time for each functional unit of the optical image measurement device according to the present embodiment. Represents. The flowchart shown in FIG. 7 represents an example of the operation of each functional unit in the on / off state.

In FIG. 6, time has passed from top to bottom as viewed in the drawing. The control unit 210 receives an inspection start input from the operator, drives the galvanometer mirrors 141A and 141B to sequentially change the direction, and sequentially scans the fundus oculi Ef along the scanning line Ri, and causes the OCT unit 150 to emit interference light. Is detected (S001). Detection results in the OCT unit 150 are sequentially transmitted to the image forming unit 220 via the control unit 210.

The image forming unit 220 receives the detection results sequentially transmitted from the OCT unit 150 and sequentially forms tomographic images along the scanning line Ri. Then, the image forming unit 220 sequentially transmits sequentially formed tomographic images to the image processing unit 230 via the control unit 210.

The image processing unit 230 receives the image data of the tomographic image along each scanning line Ri, and generates a three-dimensional image based on these m pieces of image data.

As shown in FIG. 6, adjustment of the galvanometer mirrors 141A and 141B, detection of interference light by the OCT unit 150 (S001), and formation of a tomographic image by the image forming unit 220 (S002) are performed in parallel. Then, after all the tomographic images are formed, a three-dimensional image is generated (S003). Here, as a modification of the present embodiment, a partial 3D image may be sequentially generated using a tomographic image in which no abnormality is detected.

Here, considering that the tomographic image forming process by the image forming unit 220 takes more time than the adjustment of the galvanometer mirrors 141A and 141B and the detection of the interference light by the OCT unit, as shown in FIG. The total time required for adjusting the mirrors 141A and 141B and detecting the interference light corresponding to all the frames by the OCT unit 150 is larger than the total time required for forming the tomographic images corresponding to all the frames by the image forming unit 220. It will be a short time.

Next, the operation of each functional unit in S001 and S002 will be described with reference to FIG.

First, as a premise, the eye E is placed at a predetermined measurement position (a position facing the objective lens 113), and the eye E and the apparatus are aligned. When the alignment is completed, the main control unit 211 performs focusing on the eye E. After the alignment adjustment and the focus adjustment are completed, the operator operates the operation unit 240B to request the start of the inspection.

(Operation of scanning and detection of interference light)
The main control unit 211 that has received the request to start the inspection first sets i = 1 (S101).

Then, the main control unit 211 controls the low-coherence light source 160, the CCD 184, and the like, and also controls the mirror drive mechanisms 241 and 242 to adjust the orientation of the galvano mirrors 141A and 141B to the position of the scanning point Ri1 (S102). .

The OCT unit 150 and the fundus camera unit 1A sequentially change the direction of the galvanometer mirrors 141A and 141B from the direction of the scanning point Ri1 to the direction of each scanning point Rij (j = 2 to m) to detect interference light (S103). .

The main control unit 211 increments i = i + 1 and increases the value of i by 1 (S104).

Furthermore, the main control unit 211 determines whether i> m (where m is the number of all scanning lines) (S105). If i> m (Yes in S105), the direction change of the galvanometer mirrors 141A and 141B and the detection of the interference light are terminated. If i ≦ m, the process returns to step 102 (No in S105). Thereby, the interference light corresponding to all the scanning lines (frames) can be detected.

(Image formation and display operations)
The main control unit 211 that has received the request to start the inspection first sets h = 1 (S201).

Subsequently, the image forming unit 220 collects detection signals of the fundus component corresponding to the scanning line Rh output from the CCD 184 (S202), obtains a spectrum intensity distribution for the detection signals, and uses a Fourier domain OCT technique. Is used to image the form of the eye E in the depth direction (z direction) by Fourier transforming the spectral intensity distribution of the interference light, and a tomographic image along the scanning line Rh is formed (S203).

The main control unit 211 increments by setting h = h + 1 and increases the value of h by 1 (S204).

Furthermore, the main control unit 211 determines whether h> m. If h> m (Yes in S205), the inspection is terminated. If h ≦ m (No in S205), the process returns to step 202. Thereby, tomographic images corresponding to all scanning lines (frames) are acquired.

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

The optical image measurement device 1 performs scanning of the fundus oculi Ef and detection of interference light while sequentially changing the direction of the galvanometer mirror, and in parallel with this, every time a detection result for one frame is obtained, 1 is an optical image measurement device having a configuration for performing image formation based thereon.

According to such an optical image measurement device 1, it is possible to perform the spectrum analysis and image formation that require high processing capability, as well as scanning of the eye E and detection of interference light that do not require much processing capability. it can. Thereby, the processing capability of the arithmetic and control unit 200 can be fully utilized. Therefore, the inspection can be performed quickly and the inspection time can be shortened.

[Modification 1]
The configuration described above is merely an example for favorably implementing the optical image measurement device according to the present invention. Therefore, arbitrary modifications within the scope of the present invention can be made as appropriate.

In the above embodiment, the abnormality detection described in the first embodiment is not performed. However, the abnormality may be detected after the tomographic image is formed.

For example, the abnormality detection unit 250 may sequentially receive the tomographic images along the scanning line Ri formed by the image forming unit 220 and detect the abnormality of the tomographic images in the order received.

As described above, the optical image measurement device 1 according to the present modification has a detection result for one frame in parallel with the scanning of the fundus oculi Ef and the detection of interference light while sequentially changing the orientation of the galvanometer mirror. Each time it is obtained, it is configured to perform image formation and abnormality detection based on the detection result.

By adopting such a configuration, an abnormality can be detected before the formation of all the tomographic images is completed, so that a rapid abnormality can be detected. In addition, when an abnormality is detected, the inspection can be stopped by the operator's judgment and the inspection can be started again.

[Modification 2]
Further, the abnormality detection unit 250 may detect an abnormality for the tomographic image formed by the image forming unit 220 every predetermined number of frames, for example, every 10 frames.

In this case, the control unit 210 stores a number of every 10 sheets in advance. Further, the control unit 210 counts the number of frames corresponding to the tomographic image formed by the image forming unit 220. When counting only 10 frames, the control unit 210 controls the abnormality detection unit 250 to perform abnormality detection on the tomographic image.

As described above, the optical image measurement device 1 according to the present modification has a detection result for one frame in parallel with the scanning of the fundus oculi Ef and the detection of interference light while sequentially changing the orientation of the galvanometer mirror. Each time it is obtained, an image is formed based on the detection result, and an abnormality is detected every predetermined frame.

By adopting such a configuration, it is possible to detect a case in which, for example, 10 or more consecutive abnormalities occur in the tomographic image without detecting abnormalities in all the tomographic images. Accordingly, an abnormality that makes it impossible to form a three-dimensional image can be detected, and further, the processing time can be shortened.

[Modification 3]
In addition, the abnormality detection unit 250 detects abnormality for the tomographic image formed by the image forming unit 220 every several sheets (for example, every 10 sheets), and when an abnormality is detected, 10 sheets before and after the abnormality are detected. It may be configured to detect an abnormality for a tomographic image.

In this case, as in the second modification, the control unit 210 counts the number of tomographic images formed by the image forming unit 220, and when it counts ten, the abnormality detection unit 250 applies the tomographic image to the tomographic image. An abnormality is detected, and when an abnormality is detected, the abnormality detection unit 250 performs abnormality detection for 10 sheets counted before the tomographic image in which the abnormality is detected. What is necessary is just to make it the structure which performs abnormality detection of the tomographic image for ten sheets after an image.

As described above, the optical image measurement device 1 according to the present modification has a detection result for one frame in parallel with the scanning of the fundus oculi Ef and the detection of interference light while sequentially changing the orientation of the galvanometer mirror. Image formation based on the detection result and detection of tomographic image abnormality every predetermined frame each time it is obtained, and when an abnormality is detected, the predetermined frame before and after the tomographic image in which the abnormality is detected In this configuration, anomaly detection of a number of tomographic images is performed.

With such a configuration, it is possible to reliably detect that an abnormality has occurred in 10 or more consecutive tomographic images. As a result, it is possible to detect an anomaly that hinders the generation of a three-dimensional image without completing the detection of interference light and image formation in all frames, and the overall time of inspection can be reduced. Become.

[Modification 4]
In addition, when an abnormality is detected, the direction of the galvanometer mirror when scanning the scanning line corresponding to the tomographic image in which the abnormality is detected is acquired by the number of frames, and the actual fundus corresponding to the acquired direction The position may be scanned again by driving the galvanometer mirrors 141A and 141B and changing the direction so that the position is scanned.

The operation in this case will be described. The control unit 210 acquires the number of frames from the scanning frame being performed at the time when the abnormality is detected to the tomographic image frame where the abnormality is detected. Here, the control unit 210 knows how many frames of image formation have been completed up to the tomographic image in which an abnormality has been detected, and furthermore, how many frames have been scanned. The target number of frames can be obtained by subtracting the number of frames from the number of existing frames to the tomographic image in which an abnormality is detected. Then, the control unit 210 stops changing the direction of the galvano mirrors 141A and 141B, and further returns the galvano mirrors 141A and 141B to the previous direction by the number of frames obtained from the stopped direction. The controller 210 moves the galvanometer mirror 141B by a predetermined angle, thereby changing the orientation of the galvanometer mirror in a direction orthogonal to each scan line, and aligning the direction so as to perform scanning along each scan line. Then, considering that the number of scanning lines scanned, that is, the number of frames corresponds to the number of times the direction of the galvano mirror 141B is changed, the galvano mirror 141B is obtained by multiplying the number of times by the predetermined angle described above. You can see the angle of movement. Therefore, based on the number of frames going back to the frame of the tomographic image in which the abnormality is detected, going back from the frame that was scanned when the abnormality was detected, the number of frames relative to the direction in which the galvano mirror 141B was stopped The direction of the galvanometer mirror 141B just before can be obtained. Then, the control unit 210 returns the galvanometer mirror 141B to the determined direction, and restarts scanning from the scanning along the scanning line in the direction.

The optical image measurement device according to this modification obtains the position of the galvanometer mirror when scanning corresponding to the tomographic image in which an abnormality has been detected. Further, the optical image measurement device stops driving the galvano mirror, changes the direction of the galvano mirror to the obtained position, and restarts detection of the interference light from the changed direction of the galvano mirror.

With such a configuration, when an abnormality is detected on the way, the examination can be restarted immediately from the actual position on the fundus corresponding to the tomographic image where the abnormality has occurred. As a result, it is possible to respond quickly to an abnormality without waiting for the completion of the formation of all tomographic images, thereby improving the inspection efficiency and reducing the overall inspection time.

[Modification 5]
Further, when an abnormality is detected, the position of the scan can be obtained based on a fundus image captured while performing a scan corresponding to the tomographic image in which the abnormality is detected. Furthermore, the galvanometer mirrors 141A and 141B are driven based on the current fundus image so that the obtained position is scanned, and the direction can be changed to perform scanning again.

In this case, a fundus monitor that monitors the fundus image in real time (moving image observation) during scanning is required. The fundus monitor detects a fundus image of the fundus oculi Ef based on illumination light including a near-infrared wavelength from the observation light source 101 output from the imaging device 10 while detecting interference light in a predetermined frame in real time. Is to get at the rate.

By monitoring the fundus image in real time in this way, using the fundus image generated while scanning the eye to form a tomographic image, the position of the current scan with respect to the generated fundus image Can be obtained.

The operation in this case will be specifically described. The control unit 210 has 2D coordinates in the main scanning direction (x direction) and the sub scanning direction (y direction) on the fundus. Since these coordinates are determined based on the fundus feature points (specifically, fovea, macula, blood vessel bifurcation, diseased part, etc.), the fundus moves within the frame of the fundus image that is formed. However, the coordinates for the fundus itself do not change.

When the control unit 210 forms a tomographic image corresponding to the position of an arbitrary scanning line, it indicates which position on the fundus image the signal light scanning position with respect to the fundus oculi Ef corresponds to. The coordinate information shown is generated. Then, the control unit 210 sequentially stores the fundus image and the coordinate information at the time of scanning corresponding to the tomographic image in the storage unit 212 in association with the identification information of the tomographic image.

When the control unit 210 receives a notification of abnormality detection from the abnormality detection unit 250, the control unit 210 acquires identification information of the tomographic image in which the abnormality has occurred. Further, the control unit 210 searches the storage unit 212 based on the acquired identification information, and acquires a fundus image generated at the time of scanning a tomographic image in which an abnormality has occurred. Then, the control unit 210 acquires the coordinates of the scanning position on the fundus based on the coordinate information of the fundus image. Then, the control unit 210 obtains a position corresponding to the coordinates on the current fundus image. Next, the control unit 210 drives the galvanometer mirrors 141A and 141B based on the positions, and changes the orientation of the galvanometer mirrors 141A and 141B to the direction corresponding to the coordinates in the current fundus image. Then, the inspection is started again from the direction of the galvanometer mirrors 141A and 141B.

As described above, the optical image measurement device 1 according to the present modification monitors the fundus image of the fundus oculi Ef at a predetermined frame rate during detection of interference light, and further interferes with a tomographic image in which an abnormality is detected. Based on the fundus image at the time when the light was detected, the position in the fundus image of the tomographic image in which the abnormality was detected is acquired, the position in the current fundus image corresponding to the acquired position is specified, and the In this configuration, the orientation of the galvanometer mirror is determined so as to scan the specified position.

With this configuration, when an abnormality is detected during the examination, the examination can be resumed from the scanning position corresponding to the tomographic image where the abnormality has occurred at the current fundus position. As a result, a more accurate three-dimensional image can be generated.

1 Optical Image Measuring Device 1A Fundus Camera Unit 140 LCD
141 Scanning unit 141A, 141B Galvano mirror 150 OCT unit 160 Low coherence light source 162 Optical coupler 174 Reference mirror 180 Spectrometer 184 CCD
200 Arithmetic Control Unit 210 Control Unit 220 Image Forming Unit 230 Image Processing Unit 240 User Interface 240A Display Unit 240B Operation Units 241 and 242 Mirror Drive Mechanism 250 Abnormality Detection Unit

Claims (12)

1. The low-coherence light is divided into signal light and reference light, the direction of the galvano mirror is changed, and the irradiation position of the signal light on the object to be measured is changed while the signal light is scanned with respect to the object to be measured. Interference light detection for detecting the interference light by irradiating the signal light to the object to be measured, superimposing the signal light reflected by the object to be measured and the reference light via the reference light path to generate interference light Means,
   A tomographic image forming means for forming a tomographic image of the object to be measured from a detection result obtained by scanning one frame by the interference light detecting means;
   An abnormality detecting means for detecting an abnormality of the tomographic image based on an image state of the formed tomographic image;
   With
   The tomographic image forming unit sequentially forms a tomographic image every time the interference light detection result for one frame by the interference light detecting unit is obtained,
   The abnormality detection means performs the abnormality detection every time the tomographic image for a predetermined frame is obtained,
   When the abnormality is detected, the interference light detection means stops changing the orientation of the galvanometer mirror, and restarts the detection of the interference light from the stopped orientation.
   An optical image measuring device characterized by that.
2. 2. The optical image measurement device according to claim 1, wherein the abnormality detection means detects an abnormality based on a position of the measured object depicted in the tomographic image.
3. The low-coherence light is divided into signal light and reference light, the direction of the galvano mirror is changed, and the irradiation position of the signal light on the object to be measured is changed while the signal light is scanned with respect to the object to be measured. Interference light detection for detecting the interference light by irradiating the signal light to the object to be measured, superimposing the signal light reflected by the object to be measured and the reference light via the reference light path to generate interference light And a tomographic image forming unit that forms a tomographic image of the measured object from a detection result obtained by scanning for one frame by the interference light detecting unit,
   The interference light detection means detects the interference light while sequentially changing the direction of the galvanometer mirror,
   The tomographic image forming unit forms a tomographic image every time a detection result for one frame is obtained in parallel with the detection of the interference light by the interference light detection unit.
   An optical image measuring device characterized by that.
4. An abnormality detecting means for detecting an abnormality of the tomographic image based on an image state of the formed tomographic image,
   The interference light detection means stops detecting the interference light when the abnormality is detected;
   The optical image measuring device according to claim 3.
5. 5. The optical image measurement device according to claim 4, wherein the abnormality detection means detects an abnormality based on a position of the eye to be examined depicted in the tomographic image.
6. The optical image measurement device according to claim 4, wherein the abnormality detection means performs the abnormality detection every predetermined number of frames.
7. The abnormality detection means performs the abnormality detection for each of the predetermined number of frames before and after the frame in which the abnormality is detected,
   The interference light detection means stops the detection of the interference light when at least the predetermined number of frames in which the abnormality is detected continues.
   The optical image measuring device according to claim 6.
8. An acquisition means for obtaining an orientation of the galvanometer mirror when performing the scan corresponding to the tomographic image in which the abnormality is detected;
   When the abnormality is detected, the interference light detection means changes the direction of the galvano mirror to the determined direction, and restarts the detection of the interference light from the direction of the galvano mirror.
   The optical image measuring device according to claim 4.
9. The acquisition means acquires the number of frames from the tomographic image where the abnormality is detected to the tomographic image at the time when the abnormality is detected, and the number of frames acquired from the frame at the time when the abnormality is detected Obtaining the orientation of the galvanometer mirror in the previous tomographic image;
   The optical image measuring device according to claim 8.
10. The object to be measured is the fundus;
    An imaging means for acquiring a fundus image at a predetermined frame rate during detection of interference light by the interference light detection means;
    The acquisition means acquires a position of the tomographic image in which the abnormality is detected in the fundus image based on the fundus image at the time of detecting the interference light of the tomographic image in which the abnormality is detected, Specifying a position corresponding to the acquired position in the current fundus image, and obtaining an orientation of the galvanometer mirror so as to scan the specified position;
    The optical image measuring device according to claim 8.
11. The low-coherence light is divided into signal light and reference light, the direction of the galvano mirror is changed, and the irradiation position of the signal light on the object to be measured is changed while the signal light is scanned with respect to the object to be measured. Interference light detection for detecting the interference light by irradiating the signal light to the object to be measured, superimposing the signal light reflected by the object to be measured and the reference light via the reference light path to generate interference light A tomographic image forming unit for forming a tomographic image of the object to be measured from a detection result obtained by scanning for one frame by the interference light detecting unit, and based on an image state of the formed tomographic image An abnormality detection means for detecting an abnormality in a tomographic image, and a control method for an optical image measurement device comprising:
    A detection stage for detecting the interference light;
    A tomographic image forming stage for forming the tomographic image in the frame unit;
    An abnormality detection step for detecting the abnormality each time the tomographic image for a predetermined frame is obtained;
    When the abnormality is detected,
    A galvanometer mirror stopping stage for stopping driving of the galvanometer mirror;
    Resuming the detection step from the orientation of the stopped galvanometer mirror;
    A control method for an optical image measurement device, comprising:
12. The low-coherence light is divided into signal light and reference light, the direction of the galvano mirror is changed, and the irradiation position of the signal light on the object to be measured is changed while the signal light is scanned with respect to the object to be measured. Interference light detection for detecting the interference light by irradiating the signal light to the object to be measured, superimposing the signal light reflected by the object to be measured and the reference light via the reference light path to generate interference light And a tomographic image forming means for forming a tomographic image of the measured object from a detection result obtained by scanning for one frame by the interference light detecting means. ,
    An interference light detection stage for detecting the interference light while sequentially changing the direction of the galvanometer mirror;
    A tomographic image forming step of forming the tomographic image every time a detection result for one frame is obtained in the interference light detecting step;
    The interference light detection step continuously performs the detection,
    The image forming step is performed in parallel with the interference light detecting step;
    A method for controlling an optical image measuring device.

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