JP2021119910A - Ophthalmologic system, actuation method for ophthalmologic system, and program - Google Patents

Abstract

To provide an ophthalmologic system capable of performing fundus tracking at higher speed.SOLUTION: An ophthalmologic system comprises: a photographing device including an arithmetic circuit for acquiring information on movement of a subject's eye using information on a first image of the subject's eye, correction means for correcting an acquisition position of information on a second image of the subject's eye using the acquired information on the movement, and transmission means for transmitting the information on the first image and the information on the second image; and a processing device including reception means connected to the photographing device via communication means to receive the information on the first image and the information on the second image, creation means for creating a first image using the information on the received first image and creating a second image using the information on the received second image, and display control means for making the created first image and the created second image be displayed on display means.SELECTED DRAWING: Figure 2

Description

The present invention relates to an ophthalmic system, a method of operating the ophthalmic system, and a program.

An optical coherence tomography device (hereinafter referred to as an OCT device) based on optical coherence tomography (OCT) using multi-wavelength light wave interference is known. This OCT device is currently used to obtain information on internal organs in an endoscope and information on the retina in an ophthalmic device, and its application field to the human body is expanding. The OCT device applied to the eye is becoming an indispensable device in the specialized outpatient department of the retina as an ophthalmic device.

The OCT device is a device that irradiates a sample with measurement light that is low coherence light, measures backscattered light from the sample using an interference system, and thereby makes it possible to acquire tomographic information of the sample. .. When the measurement light is applied to one point on the sample, image information in the depth direction at one point on the sample can be obtained. Further, by continuously performing this measurement while scanning the sample with the measurement light, a tomographic image of the sample can be obtained. When the OCT device is applied to the fundus, the tomographic image of the fundus can be captured with high resolution by scanning the fundus with the measurement light. Therefore, the OCT device is widely used in ophthalmic diagnosis of the retina and the like.

In such an OCT apparatus, an imaging method for obtaining a plurality of tomographic images by two-dimensionally repeatedly scanning the fundus to be measured with measurement light is common. For example, a plurality of tomographic images of the same site are acquired by scanning the same place on the fundus of the eye with measurement light multiple times, and a single tomographic image with high image quality is obtained by performing addition averaging processing on the tomographic images. Obtainable. It is also possible to obtain a three-dimensional image of the fundus by scanning the measurement light at a plurality of scanning positions of the fundus. However, when scanning the measurement light a plurality of times, the eyes may move before all the scans are completed. If the eye moves during the execution of scanning the measurement light a plurality of times, the tomographic image from a predetermined position cannot be obtained, and the target tomographic image cannot be obtained.

As a method for reducing the influence of the movement of the eye to be inspected, Patent Document 1 discloses an ophthalmologic imaging device that tracks the fundus. In the disclosed method, the intensity information of the reflected light from the fundus of the eye to be inspected received by the light receiving element in the optical head portion of the ophthalmologic imaging apparatus is transferred to the control unit. The control unit generates a plurality of frontal fundus images using the transferred intensity information. The control unit further calculates the amount of movement of the eye to be inspected using the generated plurality of frontal images of the fundus, and transfers the calculated amount of movement to the optical head side. The scanning unit that scans the measurement light in the optical head unit corrects the scanning position of the measurement light for taking a tomographic image according to the calculated movement amount. As described above, in the OCT apparatus, a process for reducing the influence of the movement of the eye to be inspected is important.

Japanese Unexamined Patent Publication No. 2013-153793

Here, the intensity information is transferred to the control unit, the fundus front image is generated by the control unit using the intensity information, the movement amount of the eye to be inspected is calculated using this, and the measurement light based on the calculated movement amount. It takes a certain amount of time for a series of processes to correct the scanning position of. Therefore, in the above-mentioned tracking, in order to reduce the influence of the movement of the eye to be inspected, it is desired to execute at a higher speed by reducing the time required for this series of processing.

Therefore, one of the objects of the embodiment of the present invention is to provide an ophthalmic system capable of tracking at a higher speed.

In order to achieve the above object, the ophthalmic system according to one embodiment of the present invention may be used.
An arithmetic circuit for acquiring information on the movement of the eye to be inspected using the information on the first image of the eye to be inspected, and a position for acquiring information on the second image of the eye to be inspected using the acquired information on the movement of the eye to be inspected. An imaging device including a correction means for correction, a transmission means for transmitting information regarding the first image and information regarding the second image, and a photographing device.
A first image is generated by using the receiving means which is connected to the photographing device by a communication means and receives the information about the first image and the information about the second image and the information about the received first image. Then, a generation means for generating the second image using the information about the received second image, and a display control for displaying the generated first image and the generated second image on the display means. A processing device including means is provided.

According to one embodiment of the present invention, tracking can be performed at a higher speed.

It is a figure which shows the schematic structure of the ophthalmic system which concerns on 1st Embodiment of this invention. It is a block diagram which shows the functional structure of the imaging part in the ophthalmology system shown in FIG. It is a figure explaining the photographed frontal image of the fundus and the tomographic image. It is a figure explaining the interlace method at the time of taking a frontal image of the fundus. It is a figure which shows the display example of the observation screen in the ophthalmic system shown in FIG. It is a flowchart for demonstrating the imaging operation of the ophthalmic system which concerns on 1st Embodiment. It is a flowchart for demonstrating the acquisition operation of the reference fundus image of the ophthalmic system which concerns on 1st Embodiment. It is a figure for demonstrating the sub-pixel interpolation operation of the ophthalmic system which concerns on 1st Embodiment. It is a flowchart for demonstrating the detection operation of fundus fixation tremor of the ophthalmologic system which concerns on 1st Embodiment. It is a figure explaining the difference between the arrangement of the structure which performs fundus tracking and the arrangement of the structure which performs the conventional fundus tracking which concerns on 1st Embodiment. It is a figure which shows the schematic structure of the ophthalmic system which concerns on the 2nd Embodiment of this invention. It is a flowchart for demonstrating the imaging operation of the ophthalmic system which concerns on 2nd Embodiment. It is a flowchart for demonstrating the detection operation of fundus fixation tremor of the ophthalmologic system which concerns on 2nd Embodiment. It is a figure for demonstrating the field image to use about the detection operation of fundus fixation fine movement which concerns on 2nd Embodiment. It is a flowchart for demonstrating the imaging operation of the ophthalmic system which concerns on 3rd Embodiment of this invention.

An ophthalmic system is exemplified as an exemplary embodiment of the present invention, and will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative positions of the components, etc. described in the following embodiments are arbitrary and can be changed according to the configuration of the device to which the present invention is applied or various conditions. Also, in the drawings, the same reference numerals are used between the drawings to indicate elements that are the same or functionally similar.

[First Embodiment]
In the present embodiment, fundus tracking, which requires high real-time performance, is performed on the main body side of the imaging device, and a tomographic image for display is generated by a processing device such as a personal computer (PC). In this way, by performing the fundus tracking on the main body side of the imaging device, it is possible to speed up the feedback control of the fundus tracking. This makes it possible to reduce tomographic image artifacts caused by fixation tremors.

Hereinafter, as an ophthalmic system according to the first embodiment of the present invention, a system including an OCT device will be described in detail with reference to FIGS. 1 to 10. In the following, first, the schematic configuration of the ophthalmic system according to the present embodiment will be described with reference to FIG. 1, and the configuration of the imaging device in the ophthalmic system will be described with reference to FIG.

(Explanation of the overall configuration of the device)
1A and 1B are configuration diagrams of an ophthalmic system according to the present embodiment, FIG. 1A shows a schematic configuration of the ophthalmic system, and FIG. 1B shows a block diagram of the functional configuration of the ophthalmic system. There is. The ophthalmology system according to the present embodiment includes an imaging device 110, a processing device 120, and a display unit 130. The imaging device 110 scans the fundus of the eye to be inspected with the measurement light in the OCT, and acquires image data related to the tomography of the fundus. In addition, the photographing device 110 scans the fundus with illumination light and acquires image data related to the front image of the fundus. The processing device 120 generates a fundus tomographic image of the eye to be inspected and a fundus frontal image from the image data acquired by the photographing device 110. The display unit 130 is connected to the processing device 120, and is capable of displaying the fundus tomographic image and the fundus frontal image of the eye to be inspected generated by the processing device 120. The photographing device 110 and the processing device 120 are connected by USB by the communication means 140, and the image data is transferred from the photographing device 110 to the processing device 120 by USB communication. Although the communication means 140 is USB here, another general-purpose communication means such as Gigabit Ethernet (registered trademark) can also be used. Further, although an example using a wired communication method is described here, a wireless communication method such as a wireless LAN, Wi-Fi, or Bluetooth (registered trademark) may be used.

(Explanation of Imaging Device 110)
Here, the photographing apparatus 110 will be described with reference to FIG. FIG. 2 is a block diagram showing a functional configuration of the photographing device 110. The photographing device 110 captures a two-dimensional image (frontal image of the fundus) of the fundus of the eye 100 to be inspected, or captures a tomographic image of the fundus. That is, the photographing device 110 functions as an example of the imaging means for capturing the frontal fundus image or the tomographic image of the eye to be inspected. The photographing device 110 includes a fundus front image capturing unit 111, a tomographic image capturing unit 112, an anterior eye portion photographing unit 113, a control unit 114, an arithmetic circuit 115, a storage unit 116, a drive system 117, and a transmission unit 118. The photographing device 110 has an optical head portion and a base portion including at least a part of an optical system for irradiating the eye to be inspected with measurement light and detecting return light from the eye to be inspected. The optical head unit includes, for example, a fundus frontal image capturing unit 111, a tomographic image capturing unit 112, and an anterior ocular segment photographing unit 113. At this time, it is not necessary for the optical head unit to incorporate all of these imaging units. For example, each optical member on the OCT optical system side from a part of the optical fiber that guides the measurement light Bm in the tomographic imaging unit 112 It may be included in another stationary housing. Further, in the optical head unit, each optical member from a part of the optical fiber that guides the interference light in the tomographic imaging unit 112 to the OCT signal detection unit 218 is another stationary housing or stage unit (base unit). ) May be included. The base unit contains, for example, a control unit 114, an arithmetic circuit 115, and a storage unit 116. The drive system 117 is composed of, for example, a stepping motor and is arranged on a base portion, and three-dimensionally drives the optical head portion to align the eye to be inspected 100. In the present embodiment, the drive system 117 can be driven by the control unit 114 or by the processing device 120. The transmission unit 118 is connected to the reception unit 125 of the processing device 120 via the communication means 140 described above. The transmission unit 118 is connected to the OCT signal detection unit 218 and the SLO signal detection unit 245, and transmits the luminance information and the interference signal, which will be described later, obtained by these detection units to the reception unit 125. A face receiving portion 108 for the subject to press the forehead and the chin is also attached to the base portion of the photographing device 110. Here, the above-mentioned alignment is performed by driving the optical head portion three-dimensionally, but for example, the face receiving portion 108 can be driven three-dimensionally to perform the alignment. That is, the alignment of the eye 100 to be inspected with respect to the optical head can be driven three-dimensionally relative to one of the optical head portion and the face receiving portion 108, and may be performed by this relative drive. .. Further, both the driving of the optical head portion and the driving of the face receiving portion may be performed, the driving of the optical head portion includes a part of the movement in the XYZ direction, and the driving of the face receiving portion remains in the XYZ. May include movement of. As described above, these drives may be any drive as long as they are drives of an optical member that changes the positional relationship between the optical head portion and the eye to be inspected.

In FIG. 2, the fundus front image capturing unit 111 acquires image data (luminance signal) for generating a fundus front image of the eye 100 to be inspected as an example of the front image acquisition means. The tomographic image capturing unit 112 scans the retina portion of the eye 100 to be inspected with the measurement light to acquire image data (interference signal) for generating a tomographic image. The anterior segment imaging unit 113 captures an image of the anterior segment of the eye to be inspected 100. An objective optical system 210 such as an objective lens is arranged so as to face the eye 100 to be inspected, and an optical division member 230 and an optical division member 240 are arranged on the optical axis thereof. By these optical dividing members 230 and 240, the optical path from the eye 100 to be inspected is the optical path to the tomographic image capturing unit 112, the optical path to the fundus front image capturing unit 111, and the anterior eye portion imaging unit 113 for each wavelength band. Branched into an optical path.

In the present embodiment, the fundus frontal imaging unit 111 is an SLO (scanning laser ophthalmoscope). Although SLO is illustrated here as a configuration for acquiring a fundus anterior image, the configuration to be used is not limited to this as long as a fundus anterior image that can be used for fundus tracking described later can be acquired. Further, in the present embodiment, the tomographic image capturing unit 112 generates a tomographic image by Fourier transforming the signal detected by spectroscopically detecting the interference light obtained by scanning the measurement light obtained by scanning the eye 100 to be examined and the reference light described later. The spectral domain method shall be used. However, as long as it is an OCT device capable of acquiring a tomographic image of the eye 100 to be inspected, various configurations corresponding to other methods can be used. In the following description, the direction perpendicular to the paper surface in FIG. 2 is referred to as an X-axis, scanning of the measurement light in the X-axis direction is referred to as horizontal scanning, and scanning in the Y-axis direction perpendicular to the X-axis direction is referred to as vertical scanning.

The tomographic imaging unit 112 includes an SLD 211, a fiber coupler 212, an OCT scanning optical system 213, a reference optical collimator 215, a reference mirror 216, and an OCT signal detection unit 218 as configurations for acquiring image data (interference signals). The light emitted from the SLD 211, which is a low coherence light source in FIG. 2, is incident on the fiber coupler 212 via, for example, an optical fiber. The fiber coupler 212 separates the incident light into the measurement light Bm and the reference light Br corresponding to the measurement light. After separation, the measurement light Bm is emitted to the OCT scanning optical system 213 by an optical fiber, and the reference light Br is emitted to the reference optical collimator 215. In the OCT scanning optical system 213 having a galvanized mirror (not shown) or the like, the incident measurement light Bm is focused on the galvano mirror, and the galvanized mirror scans the measured light Bm on the fundus of the eye. Here, the galvanometer mirror consists of a scanner that scans horizontally and a set of scanners that scans vertically. The scanned measurement light Bm reaches the retina of the eye 100 to be inspected, which is an object to be measured, via the optical dividing member 230 and the optical dividing member 240, and via the objective optical system 210. The measurement light reflected / scattered by the retina reaches the fiber coupler 212 again as return light through the objective optical system 210, the optical dividing member 230, the optical dividing member 240, and the OCT scanning optical system 213.

On the other hand, the reference light Br emitted from the fiber coupler 212 is reflected by the optical fiber through the reference optical collimator 215 by the reference mirror 216 and reaches the fiber coupler 212 again. In the fiber coupler 212, the reference light Br interferes (combines) with the return light of the measurement light Bm to generate interference light, and the interference light is incident on the OCT signal detection unit 218. In the ophthalmic system illustrated here, the optical path length of the reference light can be changed by changing the position of the reference mirror 216, and the optical path length difference from the optical path length of the measurement light can be adjusted. By substantially matching the optical path length of the measurement light with the optical path length of the reference light, good interference of these lights for tomographic image generation can be obtained. However, the adjustment of the optical path length difference may be performed not only on the reference light side but also on the measurement light side. The OCT signal detection unit 218 detects the interference light and outputs an electrical interference signal.

In the illustrated ophthalmic system, the fundus front image is acquired by the fundus front image capturing unit 111 and the light dividing member 240. The fundus frontal imaging unit 111 includes an SLO laser light source 241, an optical dividing member 242, an SLO scanning optical system 243, and an SLO signal detection unit 245. The luminous flux (illumination light) from the SLO laser light source 241 passes through the light dividing member 242 and is incident on the SLO scanning optical system 243. The SLO scanning optical system 243 collects the incident illumination light on a scanner which is an example of scanning means (not shown), and scans the illumination light on the fundus of the eye to be inspected by the scanner. In the ophthalmic system illustrated here, the scanner is composed of a polygon mirror that performs horizontal scanning (scanning in the main scanning direction) and a galvano mirror that performs vertical scanning (scanning in the secondary scanning direction). In addition to the polygon mirror, a resonance scanner may be used as the main scanning means for scanning in the main scanning direction. That is, the SLO scanning optical system 243 is configured to include a main scanning means for reciprocating the illumination light with respect to the fundus in the main scanning direction and a sub-scanning means for scanning the illumination light with respect to the fundus at a substantially constant speed. May be done. Of course, the main scanning means may be a galvanometer mirror.

The scanned SLO laser light (illumination light) is reflected by the light dividing member 240 and reaches the retina of the eye 100 to be inspected via the light dividing member 230 and the light dividing member 240, and further via the objective optical system 210. The illumination light is reflected by the retina, passes through the objective optical system 210, the light dividing member 230, the light dividing member 240, and the SLO scanning optical system 243 again, is reflected by the light dividing member 242, and reaches the SLO signal detection unit 245. .. The SLO signal detection unit 245 detects the incident light and makes an electrical SLO signal (luminance information).
Is output.

The anterior segment imaging unit 113 includes an infrared LED (not shown) that illuminates the anterior segment and a CCD camera. The infrared light emitted from the infrared LED irradiates the anterior segment of the eye via the light dividing member 230 and the objective optical system 210. The infrared light reflected by the anterior segment passes through the objective optical system 210 and the light dividing member 230, and is photographed by a CCD camera, whereby an image of the anterior segment is obtained.

Here, the SLO laser light source 241 emits light having a wavelength of 750 nm, the SLD211 emits light having a wavelength of 850 nm, and the light source for forearm illumination emits infrared light having a wavelength of 970 nm. However, the wavelength of light used in this embodiment is not limited to these wavelengths. Light of other wavelengths may be used by the tomographic imaging unit 112, the fundus frontal imaging unit 111, and the anterior ocular segment imaging unit 113. Further, here, the anterior segment imaging unit 113 is provided on the reflection side of the light dividing member 230, the fundus front image imaging unit 111 is provided on the reflecting side of the optical dividing member 240, and a tomographic image is captured in the transmission direction of the optical dividing members 230 and 240. The unit 112 is arranged. However, it is also possible to configure the photographing device 110 as an arrangement in which these configurations are interchanged on the transmission side and the reflection side, respectively. Further, in the illustrated imaging device 110, the optical dividing member 230 and the optical dividing member 240 are composed of a dichroic mirror, and the optical dividing member 242 is composed of a perforated mirror. However, these are examples, and other known members that can divide the light into two, such as a half mirror, may be used.

FIG. 3 is a diagram illustrating a tomographic image acquired by the photographing apparatus 110 and a frontal image of the fundus. In the figure, the fundus front image 250 is a fundus front image of the eye 100 to be inspected acquired by the imaging device 110, and the tomographic image 251 shows an example of a tomographic image of the retina acquired by the imaging device 110. Further, in FIG. 3, the horizontal direction 252 indicating the scanning direction (x direction) of the measurement light and the direction (y direction) perpendicular to the horizontal direction 252 are associated with the frontal fundus image 250 and the tomographic image 251. It is shown. In OCT, tomographic information regarding, for example, brightness in the depth direction at the irradiation position can be acquired from one irradiation position of the measurement light, and scanning for acquiring tomographic information from such one irradiation position is called A scan. .. Further, the image obtained by this A scan is referred to as an A scan image. In FIG. 3, it is the depth direction of the retina, and the irradiation direction at one irradiation position of the measurement light is shown as the depth (Z) direction 254. In the tomographic image 251, the acquisition position of the A scan obtained from the depth direction 254 is illustrated as the A scan 255. The dotted line 256 on the fundus front image 250 indicates the position (scanning line of the measurement light) from which the tomographic image 251 was acquired.

Although the Michelson interference system is used as the interference system in this embodiment, a Mach-Zehnder interference system may be used. It is desirable to use the Mach-Zehnder interference system when the light amount difference is large and the Michelson interference system when the light amount difference is relatively small, depending on the light amount difference between the measurement light and the reference light. Further, the present invention can be applied to optical arrangements and device configurations other than the present embodiment. For example, in the present embodiment, among the OCT devices of the Fourier domain method (FD: Fourier Domain), the OCT device of the spectral domain method (SD: Spectral Domain) is exemplified. However, the configuration described in this embodiment may be applied to other types of OCT devices. In particular, the configuration described below is also applicable to a Swept Source (SS: Swept Source) OCT apparatus using a wavelength sweep light source.

The control unit 114 controls the photographing device 110 and executes the acquisition of the above-mentioned frontal fundus image and tomographic image. The control unit 114 sends a scanning control signal to the OCT scanning optical system 213 and the SLO scanning optical system 243, and scans the eye 100 to be inspected with measurement light or illumination light in the X direction and the Y direction. Further, the control unit 114 also executes position control of a focus lens (not shown) provided in the fundus front image capturing unit 111 and the tomographic image capturing unit 112, and a reference mirror 216 provided in the tomographic image capturing unit 112. The arithmetic circuit 115 is connected to the SLO signal detection unit 245, the control unit 114, and the storage unit 116. The calculation circuit 115 performs a two-dimensional correlation calculation of a plurality of frontal images of the fundus, which will be described later, in a hardware circuit (for example, FPGA or ASIC). As a result, the amount of displacement between the frontal images of the fundus can be obtained, and the fundus tracking operation is performed by correcting the acquisition position of the tomographic image by the obtained amount of displacement. Further, the storage unit 116 stores the reference fundus image used in fundus tracking and the obtained displacement amount.

(Explanation of processing equipment)
Next, the processing apparatus 120 will be described. FIG. 1B is a block diagram showing a functional configuration of the processing device 120. The processing device 120 includes an image generation unit 121, a storage unit 122, an image evaluation unit 123, a reception unit 125, and a display control unit 126. The image generation unit 121 is connected to a storage unit 122, a reception unit 125, and a display control unit 126 in the processing device 120. The display control unit 126 is also connected to the display unit 130, and causes the display unit 130 to display, for example, a fundus frontal image or a tomographic image generated by the image generation unit 121, an input screen for an imaging instruction, or the like. The image generation unit 121 Fourier transforms, for example, the interference signal obtained from the OCT signal detection unit 218 received by the reception unit 125, and converts the data after the Fourier transform into brightness or density information to obtain the above-mentioned depth of the eye to be inspected. An A-scan image in the vertical direction (Z direction) is acquired.

By performing such an A scan a plurality of times at different positions along a predetermined transverse direction on the retina by the OCT scanning optical system 213, a plurality of A scan images can be acquired. For example, if the measurement light is scanned in the X direction, a plurality of A-scan images arranged on the XZ plane can be obtained, and if the measurement light is scanned in the Y direction, a plurality of A-scan images arranged on the YZ plane can be obtained. A method of scanning the eye 100 to be inspected with measurement light in a predetermined transverse direction in this way is referred to as a B scan, and a tomographic image obtained by combining these plurality of A scan images is referred to as a B scan image. By repeating this B scan in the predetermined direction of the eye 100 to be inspected by the OCT scanning optical system, a plurality of B scan images can be acquired. For example, three-dimensional information of the XYZ space can be obtained by repeating the scanning of the measurement light for acquiring the B scan image of the XZ surface while shifting it in the Y direction. Such a scan is referred to as a C scan, and data composed of a plurality of obtained B scan images is referred to as three-dimensional data (C scan image).

The storage unit 122 stores the image generated by the image generation unit 121, the photographing parameters used for photographing the eye to be inspected, and the like. The image evaluation unit 123 evaluates the image generated by the image generation unit 121 or the image of the storage unit 122. The evaluation of the image is performed by parameters such as the sharpness of the entire image and the average brightness. At this time, when the evaluation item is sharpness, the higher the value, the higher the evaluation, and in the case of the average brightness value, the evaluation target is that the brightness is not too dark and is equal to or higher than a predetermined value. The image evaluation unit 123 also determines whether the image is defective. Examples of the image defect determined here include "blink marks" remaining in the image due to blinking of the eye to be inspected during imaging, "interlaced fringes" due to fixed vision fine movement, insufficient contrast, and the like.

(Method of generating a frontal image of the fundus using the interlace method)
Next, in the present embodiment, a method of generating a frontal fundus image will be described. The control unit 114 sends a scanning control signal to the SLO scanning optical system 243, and scans the fundus of the eye 100 to be inspected with illumination light in the X direction and the Y direction. Further, the control unit 114 also controls the position of a focus lens (not shown) that focuses the illumination light on the fundus. The image generation unit 121 arranges the luminance information (luminance value) obtained as the signal information from the SLO signal detection unit 245 based on the scanning signal, and generates an image of the front of the fundus in the XY plane. However, the method of capturing and generating the frontal fundus image applicable to this embodiment is not limited to the method described here. For example, other methods such as a fundus camera may be used.

In the present embodiment, the frontal image of the fundus is acquired by using the interlace method while controlling the SLO scanning optical system that scans the fundus. By using the interlace method, it is possible to shorten the acquisition time of the frontal fundus image, and it is possible to shorten the feedback control time of the fundus tracking. When a fundus frontal image is acquired using the SLO scanning optical system, the fundus frontal image is composed of signals obtained from scanning lines L01 to L20, for example, as shown in FIG. The interlaced method is a scanning method different from the progressive method in which each main scan (scanning in the X direction) in the raster scan is sequentially performed in the sub-scanning direction (Y direction). More specifically, it is a method of obtaining each signal while alternately performing the odd-numbered main scans and the even-numbered main scans in the sub-scanning direction. At this time, two types of images including an image corresponding to the plurality of odd-numbered main scanning lines and an image corresponding to the even-numbered plurality of main scanning lines are sequentially displayed in accordance with signal acquisition. As a result, the resolution of one image is lowered, but the time required for image acquisition can be reduced to 1/2. Further, the image evaluation unit 123 analyzes the fundus front image and evaluates the fundus front image with respect to the above-mentioned evaluation items. The storage unit 122 is connected to the image generation unit 121 and the display unit 130, and the B-scan image (tomographic image) generated by the image generation unit 121, the three-dimensional data, the fundus front image, and the anterior eye portion image are stored in the storage unit 122. Will be done. The display unit 130 displays the tomographic image, the fundus frontal image, and the anterior eye portion image stored in the storage unit 122 in the observation screen displayed on the display unit 130.

Next, in the ophthalmology system including the photographing device 110, the processing device 120, and the display unit 130 described above, the flow from the observation of the eye 100 to be examined to the acquisition of a tomographic image or the like will be described. First, the observation screen will be described with reference to FIG. FIG. 5 shows an example of the observation screen 300 displayed on the display unit 130 when observing the eye to be inspected. The observation screen 300 displays an anterior segment image 310, a fundus front image 301, a tomographic image 302, 303, 304, 305, a focus adjustment slider 308, a reference mirror position adjustment slider 307, and a measurement start button 306. .. The dotted line 309 superimposed and displayed on the fundus front image 301 indicates the scanning position of the measurement light when acquiring the tomographic images 302, 303, 304, 305 on the fundus front image 301.

In the actual shooting, the operator positions the eye to be inspected 100 in front of the objective optical system 210 while observing the anterior eye portion image 310. After that, the frontal surface image is acquired by scanning with the illumination light in the XY direction by the SLO scanning optical system 243, and the tomographic image is acquired by scanning the measurement light with the measurement light in the XY direction by the OCT scanning optical system 213. The operator operates the focus adjustment slider 308 and the reference mirror position adjustment slider 307 using a mouse or mouse cursor (not shown) while observing the fundus front image 301 and the tomographic images 302, 303, 304, 305. As a result, the focus of the tomographic image, the position of the reference mirror 216, and the like are adjusted. These tomographic images 302, 303, 304, 305 and the fundus anterior image 301 are appropriately updated according to the scanning of the OCT scanning optical systems 213 and 243. By operating a scanning position changing means (not shown) such as a mouse or a touch panel, the operator moves the position of the dotted line 309 superimposed and displayed on the fundus front image 301, and sets a corresponding desired scanning position.

(Flowchart of fundus tomographic image generation operation)
Next, the details of the processing performed at the time of taking a tomographic image of the fundus by the ophthalmic system of the present embodiment will be described with reference to the flowchart shown in FIG. In the present embodiment, the illumination light for photographing the fundus front image 301 is scanned by an interlace method in order to increase the frame rate. In the interlaced method, the odd-numbered scanning lines and the even-numbered scanning lines are the odd-numbered scanning lines when the scanning lines of the illumination light drawn on the fundus when the frontal image of the fundus is acquired are numbered in order from the top of the image. The image is acquired separately from the even-numbered lines which are the scanning lines of. That is, when the pixel strings in one image of the front of the fundus are numbered from the top of the image, the image information of the odd-numbered pixel strings and the image information of the even-numbered pixel strings are separately acquired. FIG. 4 is a diagram illustrating an example of the interlaced method. In FIG. 4, the scanning lines of the illumination light are numbered L01, L02, L03, ... L20 in order from the top of the fundus front image. In the interlaced method illustrated here, the frontal image of the fundus of the odd-numbered lines is composed of scanning lines L01, L03 ... L19. The front fundus image of even-numbered lines is composed of scanning lines L02, L04 ... L20. Here, the image of the front surface of the fundus of the odd-numbered line and the image of the front surface of the fundus of the even-numbered line are referred to as an image of the odd-numbered field from which the odd-numbered line is acquired and an image of the even-numbered field from which the even-numbered line is acquired, respectively.

In actual fundus photography, when the measurement start button 306 is pressed, the imaging process shown as the flowchart of FIG. 6 is started. Hereinafter, the details of the shooting process will be described with reference to the flowchart. In the photographing process, first, a reference fundus image, which is a frontal image of the fundus and serves as a reference when measuring the subsequent movement of the eye to be inspected, is generated. Then, for example, the frontal fundus image is acquired in synchronization with the start or end timing of the 1B scan described later, the deviation between the images with the reference fundus image is obtained, and this is acquired as the movement of the eye to be inspected. If the deviation between the images is larger than the threshold value, it is considered that the tomographic image obtained from the B scan to be started from now on is likely to be obtained from a position different from the previously acquired tomographic image, and the start position of the B scan is set. Correct according to the acquired deviation amount. Then, the tomographic image is acquired from the corrected position. Such a process of changing the start position of the B scan (irradiation position of the measurement light) according to the movement of the fundus is called fundus tracking. By performing such fundus tracking at the time of acquiring a tomographic image, it is possible to acquire a tomographic image without significantly deviating from a desired position.

<Step S100>
In step S100, the control unit 114 controls the fundus anterior image capturing unit 111 to acquire a reference fundus image for performing fundus tracking. The storage unit 116 stores the acquired reference fundus image for use when performing fundus tracking. It should be noted that the fundus front image capturing unit 111 acquires the luminance information from the fundus and does not actually generate the image. Therefore, the control unit 114 generates image information by arranging the luminance information in the plane corresponding to the display screen of the fundus front image based on the scanning position information of the SLO scanning optical system 243, and uses this. The subsequent processing is being performed. However, in the tracking process described later, this image information is used as an image according to the frontal fundus image. Therefore, in the following description, the control unit 114 will acquire an image of the front surface of the fundus and use it to perform detection processing of the amount of fixation and fine movement of the fundus. The details of the operation of acquiring the reference fundus image will be described later.

<Step S110>
In step S110, the arithmetic circuit 115 calculates the amount of fixation tremor of the eye to be inspected by detecting the position change of the fundus front image with the passage of time and obtaining the amount thereof. The details of the calculation operation of fundus fixation tremor will be described later.

<Step S120>
In step S120, the arithmetic circuit 115 determines whether or not the amount of fixation tremor calculated in step S110 is larger than the threshold value. The threshold value can be set arbitrarily. For example, the amount of fixation tremor that causes an artifact in the tomographic image can be set as the threshold value. When acquiring tomographic images continuously, the acquisition position of the tomographic image is not usually corrected. However, the amount of fixation tremor becomes large, and when a tomographic image is acquired without considering this fixation tremor, there is a high possibility that a tomographic image at a desired position cannot be acquired and an artifact occurs. Therefore, in step S120, a threshold value is set in consideration of the possibility of occurrence of artifacts, and it is determined whether or not the calculated fixation tremor amount exceeds this threshold value.

<Step S130>
Step S130 is executed when the amount of fixation tremor is larger than the threshold value according to the determination in step S120, and the control unit 114 transmits the determination result to the processing device 120. This determination result is transmitted to the processing device 120. The processing device 120 discards the tomographic image data that failed to be acquired based on the determination result, and replaces the tomographic image data acquired by reacquiring (rescanning) the tomographic image from the same scanning line. Is possible. In the present embodiment, a replacement tomographic image is obtained by rescanning, but it can also be used as a replacement tomographic image constructed by using, for example, an adjacent tomographic image or an adjacent tomographic image.

<Step S140>
In step S140, the control unit 114 corrects the acquisition position of the tomographic image by changing the position of the scanning line by the amount of fixation tremor detected in step S110. Specifically, the correction of the acquisition position of the tomographic image is performed by changing the scanning control signal given to the OCT scanning optical system 213 by the control unit 114.

<Step S150>
In step S150, the acquisition of the tomographic image is started in response to the completion of the correction of the tomographic image acquisition position by the control unit 114. Specifically, at the corrected scanning position, scanning of the fundus with the measurement light is started. Then, based on the interference signal acquired by the OCT signal detection unit 218 by this scanning, the tomographic image capturing unit 112 starts acquiring (generating) a tomographic image (B scan image) of the fundus of the eye to be inspected. The generated tomographic image is displayed on the display unit 130 by the processing device 120 in the display format illustrated in FIG. 5, for example.

<Step S160>
In step S160, the control unit 114 determines whether or not the measurement (acquisition of the tomographic image) has been completed. Since the tomographic image by OCT has a lot of noise, for example, the tomographic image is acquired a plurality of times for the same scanning line, the acquisition results are added and averaged, and the noise is reduced. Further, as described above, a plurality of B-scan images (tomographic images) are acquired while shifting the position of the B-scan, and the obtained tomographic images are combined to obtain a three-dimensional image (C-scan image) of the fundus. You can also. The end of the measurement is determined by whether or not the acquisition of the tomographic image of a predetermined number of times is completed or the acquisition of the tomographic image from the predetermined area is completed. When the acquisition of the tomographic image is completed, the shooting operation is completed. If the acquisition is not completed, the control unit 114 shifts the flow to step S110, and repeats the subsequent operations until the acquisition is completed a predetermined number of times.

(Reference Flowchart of fundus image acquisition operation)
Next, the operation of acquiring the reference fundus image executed in step S100 of FIG. 6 described above will be described with reference to the flowchart of FIG. 7. When the operation of acquiring the reference fundus image is started, the control unit 114 executes the processes after step S200 described below.

<Step S200>
In step S200, the control unit 114 controls the fundus frontal image capturing unit 111 and acquires an image from the above-mentioned odd-numbered fields (fields including odd-numbered scanning lines L01, L03, ... L19 in FIG. 4) in the fundus. do. The storage unit 116 stores an image of an odd-numbered field acquired from the odd-numbered line.

<Step S210>
In step S210, the control unit 114 controls the fundus frontal image capturing unit 111 and acquires an image from the above-mentioned even-numbered fields (fields including even-numbered scanning lines L02, L04, ... L20 in FIG. 4) in the fundus. do. The storage unit 116 stores an image of an even-numbered field acquired from the even-numbered line. In the present embodiment, in the above-mentioned odd-numbered lines and even-numbered lines, a plurality of pixels of the display screen when displaying the generated frontal fundus image are arranged in the extending direction of the lines. It is configured. Specifically, each of the pixels arranged in, for example, the line direction of the display screen is arranged so as to correspond to the acquisition position of the luminance value obtained when, for example, the illumination light is scanned along the line.

<Step S220>
In step S220, the arithmetic circuit 115 performs a two-dimensional correlation calculation on the image of the odd-numbered field and the image of the even-numbered field. The two-dimensional correlation calculation is performed as follows. The cross-correlation coefficient between image 1I1 (X, Y) and image 2I2 (X, Y) can be obtained from the cross-correlation function defined by the following equation (1).

R12 (u, v) = ∫∫I1 (X, Y) I2 (X + u, Y + v) dXdY ... (1)

If this cross-correlation function has a clear peak, it means that the pixel located at the peak position (u0, v0) shows a high degree of agreement between the image 1 and the image 2. The presence or absence of correlation can be determined by comparing R12 (u, v) at the peak position in Eq. (1) with a predetermined threshold value. Image 1 and image 2 can be aligned with reference to such pixels having a high degree of coincidence. Note that the calculation method for obtaining the best degree of matching in this way is a method other than cross-correlation calculation, various image processing methods (method using various correlation functions, method using Fourier transform, method based on matching of feature points). It can be used. That is, these other methods may be used in the present embodiment.

In addition, the peak can be obtained stepwise in the mutual correlation coefficient. First, the arithmetic circuit reduces the image 1 and the image 2 to generate a hierarchical image. Specifically, the pixels constituting one image are combined by adding a predetermined number of units, and the number of pixels constituting the one image is reduced (reduction of the image). Then, rough processing is performed on the hierarchical image obtained by reducing the image, and the coordinate position where a desired pattern (similar pattern between images) exists is detected. After that, in the vicinity of the detected coordinates, detailed processing is performed using, for example, an image consisting of the original number of pixels, and the exact position of the desired pattern is detected. In such a coarse-dense search method, a rough search is performed to identify the approximate position of a desired pattern, and a detailed search is performed in the specified range based on the result, and so on, a stepwise matching process is performed. As a result, the total processing time can be shortened by sequentially examining only the necessary parts without performing a detailed search over the entire image.

Further, by performing interpolation calculation from several points near the peak of the correlation coefficient, it is possible to obtain points having a high degree of coincidence in sub-pixel units. FIG. 8 is a diagram illustrating such interpolation processing in units of sub-pixels. FIG. 8A is a diagram showing the positional relationship between the original peak 401 of the correlation coefficient and the pixels arranged in the vicinity thereof. More specifically, it is a figure which shows the pixel P (u0, v0) 400 which shows a peak in a correlation calculation, the position of an actual peak 401, and the coordinates of the adjacent pixel.

In the present embodiment, in order to obtain the position of the peak 401, the first-order interpolation shown in FIG. 8B is performed in the X-axis direction and the Y-axis direction, respectively. FIG. 8B is a vertical axis plot of pixels P (u0, v0), adjacent pixels P (u0-1, v0) and P (u0 + 1, v0) in the X-axis direction, and their correlation coefficients. .. A straight line is drawn between the pixel P (u0, v0) indicating the peak in the correlation calculation and the adjacent pixels P (u0-1, v0), P (u0 + 1, v0), and the one having the larger slope is adopted. In FIG. 8B, a straight line connecting the adjacent pixels P (u0-1, v0) and the pixels P (u0, v0) is adopted. Then, from the remaining points, draw a straight line that has the same absolute value as the straight line adopted but has different positive and negative values. The coordinates of the intersection of these two straight lines (intersection 402 in FIG. 8B) is set as the X coordinate of the original peak 401. The same interpolation calculation is performed on the Y-axis, and the X-coordinate and Y-coordinate of the peak 401 in sub-pixel units can be obtained. Although linear interpolation is performed here, a quadratic function that passes through three points may be created to obtain the extremum. Further, other interpolation methods such as interpolating with a three-dimensional curved surface from more points surrounding the peak to obtain the peak may be used.

<Step S230>
In step S230, the control unit 114 determines whether or not there is a correlation by comparing the correlation coefficient based on the correlation calculation result in step S220 with a predetermined threshold value. If the image in at least one field is affected by nystagmus due to blinking or fixation tremor at the time of acquisition, the correlation value becomes low. When the image of the odd-numbered field and the image of the even-numbered field have no correlation by comparison with the threshold value, the control unit 114 returns the flow to step S200, and the process from the acquisition of the image of the odd-numbered field is performed again. If it is determined that there is a correlation between these images, the flow shifts to step S240.

<Step S240>
In step S240, the control unit 114 determines whether or not the displacement amount of the peak position based on the correlation calculation result in step S220 is close to (0,0.5). Here, the X direction is in pixel units, and the Y direction is in scan line units in the interlaced field. More specifically, in the Y direction, 1 corresponds between, for example, two scan lines in an odd-numbered frame image. That is, 0.5 in the Y direction here corresponds to the amount of displacement between one scanning line in the odd-numbered field, the scanning line in the even-numbered field closest to the one scanning line, and the one scanning line. When the displacement amount is close to (0,0.5), the odd-numbered field image and the even-numbered field image are considered to be images acquired continuously while the influence of fixation tremor is small, and the flow is stepped. It is transferred to S250. If the amount of displacement is large, the flow is returned to step S200, and processing from the acquisition of the image of the odd-numbered field is performed again.

<Step S250>
In step S250, the arithmetic circuit 115 synthesizes the odd-numbered field image acquired in step S200 and the even-numbered field image acquired in step S210 to create frame data (new frontal image) of the fundus frontal image. The image data of the odd-numbered fields is combined with the odd-numbered lines of the frame data to be combined, and the image data of the even-numbered fields is combined with the even-numbered lines of the same frame data. That is, the odd line is an area corresponding to the image data of the odd field in the new front image, and the even line is the area corresponding to the image data of the even field in the new front image.

<Step S260>
In step S260, the control unit 114 stores the frame data synthesized in step S250 in the storage unit 116 as a reference fundus image for fundus tracking. By executing the above processing, a frame image obtained by synthesizing an odd-numbered field image and an even-numbered field image having a small displacement amount can be used as a reference fundus image for fundus tracking. Therefore, it is possible to increase the resolution in the vertical direction, whereas the field image is used as the reference fundus image when detecting the amount of fixation tremor, which will be described next. The reference fundus image obtained here can also be sent to the processing device 120 and displayed on the display unit 130 by the processing device 120. Further, the original luminance data used for generating the reference fundus image and the luminance data obtained from the fundus for the fixation vision fine movement detection described later are also used in the processing device 120, and the image generation unit 121 generates the fundus front image. Will be done. The generated frontal fundus image is displayed on the display unit 130 by the processing device 120 in the display format illustrated in FIG. 5, for example.

In the present embodiment, the correlation between the odd-numbered field image and the even-numbered field image is obtained in step S220 described above. At that time, it can be said that the image determined to have a high interphase value is an image without an artifact for which the interphase value is required. Therefore, it is considered that the reference fundus image obtained in step S260 is obtained by synthesizing a good image quality image without artifacts. In this way, by considering the image quality of the image used for synthesizing the reference fundus image in the process of obtaining the interphase value, it is possible to select an image with less distortion due to the movement of the eye to be inspected for the reference fundus image. As a result, the displacement of the fundus due to the fixed vision fine movement described later can be acquired more accurately.

In the description of this embodiment, an example of acquiring an odd-numbered field image and an even-numbered field image as a set has been described. That is, when the flow is returned to step S200 in step S230 or step S240, an odd-numbered field image and an even-numbered field image are newly acquired, and the interphase value between these images is obtained. However, the image acquisition format is not limited to this. For example, the sequential correlation may be obtained for each field, and in the case of the sequential correlation between the image of the odd field and the image of the even field in step S240, it may be compared with the displacement amount (0, 0.5). In this case, in the case of the correlation in the order of the image of the even field and the image of the odd field, it is compared with the displacement amount (0, −0.5). The same effect can be obtained as such an image acquisition mode.

(Flowchart of fundus fixation microtremor detection operation)
Next, the fundus fixation tremor detection operation executed in step S110 of FIG. 6 will be described with reference to the flowchart of FIG. In the following description, since the scanning of the illumination light for acquiring the frontal fundus image starts from the L01 line as shown in FIG. 4, a case where an odd number field is used as a reference will be described. In the following example, an offset is not added when the reference fundus image and the image of the odd field are correlated, and an offset is added to the image of the even field when the correlation is obtained with the image of the even field. ..

<Step S300>
When the fundus fixation tremor detection operation in step S110 is started, the control unit 114 starts the operation according to the flowchart of FIG. First, in step S300, the control unit 114 controls the fundus front image capturing unit 111 to start scanning the illumination light (acquisition of the fundus front field image) in order to acquire an image of an odd number field. The arithmetic circuit 115 generates an odd-numbered field image by using the output from the SLO signal detection unit 245 that has obtained the reflected light from the fundus.

<Step S310>
In step S310, the arithmetic circuit 115 generates, for example, a frame image consisting of 20 scanning lines shown in FIG. 4 from the image of the odd-numbered field acquired in step S300. This process is hereinafter referred to as framing. Frame is done as follows. First, a data area having twice the number of lines of data in an odd field is prepared. Next, the data of n lines (n = 1, 2, 3, ..., N / 2: N = 20 in the example of FIG. 4) of the data of the odd field is copied to the 2n-1 line of the data area. Further, the data of the 2n-1 line of the data area is copied to the 2n line of the data area. As a result, the scan line data of the odd field is duplicated. Here, since the data of the scanning lines of the odd-numbered fields is written twice on the scanning lines of the data area for framing, the expression "copy" is used. From the above, it is possible to prepare image data having twice the number of lines (corresponding to frame data) of the field data and having the same data for the odd-numbered line and the next even-numbered line.

<Step S320>
In step S320, the calculation circuit 115 performs a two-dimensional correlation calculation on the reference fundus image acquired in step S100 with the fundus frontal image framed in step S310. Since the correlation calculation here is a correlation calculation between frame data, it is considered that there is no variation in the X direction in pixel units, but in the Y direction, the displacement amount in one scanning line unit is obtained. Further, in the two-dimensional correlation calculation, the displacement amount in sub-pixel units is obtained according to the method described in step S220.

<Step S330>
In step S330, the arithmetic circuit 115 determines whether or not the field image acquired in step S300 is an image of an odd number field. In the case of an odd-numbered field image, the control unit 114 shifts the flow to step S340. If not, that is, if the acquired image is an even field image, the flow proceeds to step S350.

<Step S340>
Since the displacement amount obtained in step S320 is calculated based on the image of the odd-numbered field, it is necessary to take this into consideration. In the case of an odd-numbered field image, in step S340, the arithmetic circuit 115 does not add an offset in the Y-axis direction to the framed image data (ie, offset 0). The control unit 114 maintains the image data as it is and shifts the flow to step S360.

<Step S350>
When the displacement amount obtained in step S320 is calculated based on the image of the even field, it is necessary to take this into consideration. Therefore, in the case of an even-numbered field image, in step S350, the arithmetic circuit 115 adds an offset of 1 in the Y-axis direction to the framed image data. Then, the process proceeds to step S360. This offset of 1 takes into consideration the difference in position between the odd-numbered field and the even-numbered field in the 2n-line data constituting the framed data area.

<Steps S360, 370>
By the above operation, the amount of displacement between the reference fundus image and the frontal image of the fundus acquired in step S300, that is, the amount of fixation tremor of the eye to be inspected can be obtained. In step S360, the control unit 114 stores the fixation fine movement amount obtained by the arithmetic circuit 115 in the storage unit 116. Further, in step S370, the control unit 114 stores the fundus anterior image used for calculating the fixed vision fine movement amount in the storage unit 116. With the above, the detection operation of fixation tremor is completed. By executing the above processing, the amount of fixation tremor can be obtained. Here, the movement of the eye to be inspected is described as the amount of fixation tremor, but the amount of fixation tremor includes information about, for example, the amount of movement, the direction of movement, the rotation of the eye to be inspected, and the like. It is desirable to be grasped as information on the movement of. Further, in the above-described example, information on movement is obtained by a two-way correlation calculation using two images, which is so-called pattern matching. However, the method of obtaining information on movement is not limited to the two-dimensional interphase calculation using an image, and may be obtained by phase-limited correlation using, for example, phase.

In the above description, an example in which an odd number field is used as a reference is shown, but an even number field may be used as a reference. In that case, no offset is added when the reference fundus image and the field image obtained by framing the even-numbered field image are correlated. On the other hand, when the field image obtained by framing the odd-numbered field image and the reference fundus image are correlated, an offset (for example, an offset of -1 in the Y-axis direction) is added.

In this embodiment, an example of synthesizing a frame image as a reference fundus image from an odd-numbered field image and an even-numbered field image is shown. However, the reference fundus image may be obtained from a field image that is not composited. For example, an odd-numbered field image and an even-numbered field image can be acquired, the sharpness and the average luminance value can be evaluated by the image evaluation unit 123, and the one with the higher evaluation can be used as a reference fundus image. When the image of the odd-numbered field is used as the reference fundus image, the offset is 0 when correlating with the image of the odd-numbered field. Further, when correlating with an even-numbered field image, an offset of 0.5 is added in the Y direction. When the even-numbered field image is used as the reference fundus image, an offset of -0.5 is added in the Y direction to correlate with the odd-numbered field image, and an offset of 0 is added to correlate with the even-numbered field image. And. The unit of this offset is the scanning line unit in the interlaced field. Correlation is done on a sub-pixel basis. In addition, when the image of the odd-numbered field is used as the reference fundus image, only the image obtained from the odd-numbered field is correlated with the image of the front of the fundus, and when the image of the even-numbered field is used as the reference fundus image, it is obtained from the even-numbered field. It can also be configured to correlate with only the images.

Generally, in the OCT apparatus, the frontal fundus images acquired by the main body of the photographing apparatus 110 at different times are transferred to the processing apparatus 120 side including a PC or the like. On the processing device 120 side, information on the movement of the eye to be inspected, such as the amount of movement (deviation amount) of the eye to be inspected, the direction of movement, and the rotation of the eye to be inspected, is calculated from the comparison of the acquired frontal images of the fundus. Then, the calculated information on the movement is transferred to the main body of the photographing device 110, and the scan for measuring light scanning arranged in the imaging device is controlled by reflecting the information on the movement to determine the acquisition position of the tomographic image. to correct. Therefore, there is a time lag between detecting the movement of the eye to be inspected and correcting the scanning position.

Such time lags need to be considered for proper tracking in response to fast eye movements. That is, when a fast eye movement such as fixation tremor occurs, even if fundus tracking is performed according to this movement, the eye moves further while calculating and instructing the fixation tremor amount for correction, and a fault occurs. It is possible that the distortion of the image cannot be completely reduced. In addition, the difference value and decorrelation value between tomographic images obtained in such a state are larger than the original values. For example, when an attempt is made to generate an OCTA image, an artifact such as a white line occurs on the image. It is possible that it will end up.

In the present embodiment, as described above, the fundus tracking is performed using the control unit 114, the arithmetic circuit 115, and the storage unit 116 provided in the main body of the photographing device 110. Hereinafter, the relationship between the configuration related to the control of fundus tracking and the configuration related to the generation of the fundus front image and the fundus image according to the present embodiment will be described with reference to FIG. 10A and 10B schematically show a process performed on the photographing device side and a process performed on the processing device side, FIG. 10A shows the present embodiment, and FIG. 10B shows a conventional mode. Shown.

Referring to FIG. 10B, in the conventional embodiment, on the imaging device 1110 side, the acquisition of the luminance information for the frontal image of the fundus, the acquisition of the interference signal, and the control of the OCT scanning optical system 213 at the time of acquiring the interference signal are performed. Will be done. Further, on the processing device 1120 side connected to the photographing device 1110, the amount of misalignment for tracking is calculated according to the generation of the frontal surface image of the fundus based on the acquired luminance information and the generation of the tomographic image based on the interference signal. .. More specifically, the processing device 1120 obtains the amount of displacement of the fundus (offset amount of the frontal fundus image) from the brightness information of the fundus acquired from the photographing device 1110 or from the frontal image of the fundus generated by the processing device 1120. .. The obtained misalignment amount is sent from the processing device 1120 to the photographing device 1110, and the scanning optical system in the OCT device is controlled based on this misalignment amount. As described above, since the configuration involved in the control of fundus tracking exists separately on the imaging device 1110 side and the processing device 1120 side, the above-mentioned time lag due to data exchange occurs. This time lag is preferably eliminated as much as possible in order to speed up fundus tracking.

On the other hand, in the ophthalmic system according to the present embodiment, as shown in FIG. 10A, most of the configurations related to the control of fundus tracking are arranged on the imaging device 110 side, and the fundus is located only on the imaging device 110 side. Tracking is controlled. That is, all the processes in the flowchart shown in FIG. 6 can be executed by the control unit 114, the arithmetic circuit 115, and the storage unit 116 arranged in the photographing device 110. Specifically, the acquisition of the luminance information of the fundus, the calculation of the amount of misalignment from the image based on the luminance information or the luminance information, and the control of the scanning optical system based on the amount of misalignment are all performed by the photographing apparatus 110. Be struck. With such a configuration, it is possible to eliminate the factor that causes the above-mentioned time lag and to speed up the fundus tracking.

As described above, in the present embodiment, the fundus tracking, which requires high real-time performance (high speed), is performed on the imaging device 110 side, so that the feedback control executed for fundus tracking can be speeded up. .. As a result, it is possible to reduce the artifacts of the tomographic image caused by the fixation tremor and the like. Further, when the movement amount, which is information on the movement of the eye 100 to be examined, exceeds the threshold value in step S130 described above, for example, the corresponding tomographic image is reacquired. In the present embodiment, since the time required to start the reacquisition is shortened, the amount of movement of the eye 100 to be inspected at the time of reacquisition is reduced as compared with the conventional case, and the photographing time is shortened, which imposes a burden on the subject. More mitigated.

In the above-described embodiment, the frontal image of the fundus is acquired by the interlace method. However, the acquisition of the frontal fundus image is not limited to this method, and may be acquired by, for example, a progressive method. Hereinafter, a case where a frontal fundus image is acquired by a progressive method will be described. The progressive method is a scanning method in which each main scan (scanning in the X direction) in the raster scan is performed in order in the sub-scanning direction (Y direction), and is obtained from scanning lines L01 to L20 as shown in FIG. 5, for example. This is a method of constructing an image of the front of the fundus from the signal. That is, in the progressive method, the signals constituting one fundus frontal image are obtained from all the scanning lines arranged for the image. By obtaining the information on the frontal fundus image from all the scanning lines in this way, it is possible to obtain an image having a high resolution as compared with the case where the image is constructed by the interlace method. However, on the other hand, the time required to acquire one image is twice that of the interlaced method.

In the progressive method, the control unit 114 scans the illumination light in the order of the scanning lines L01 to L20 shown in FIG. 4, for example, and the process of acquiring the reference fundus image ends when the scanning ends. Therefore, in step S100 in FIG. 6, the processing of steps S210 to S250 shown in FIG. 7 is not performed by the control unit 114 or the arithmetic circuit 115. In step S200, the control unit 114 executes the process of acquiring the fundus front image from the field using all the scanning lines, instead of acquiring the fundus front image for the odd-numbered field. The acquired frontal fundus image is stored in the storage unit 116 as a reference fundus image for tracking in step S260.

In step S110, the control unit 114 again acquires the fundus frontal image by the progressive method. The calculation circuit 115 uses the front surface image of the fundus and the reference fundus image obtained in step S110 to perform the two-dimensional correlation calculation of step S320 in FIG. 9 to obtain the amount of misalignment between these images. In the two-dimensional correlation calculation performed here, the displacement amount in one scanning line unit is obtained in the Y direction in the same manner as in step S320 described above. At that time, the displacement amount may be obtained in sub-pixel units as in the case of step S220 described with reference to FIG. 7. In the case of the progressive method, since the frontal fundus image is obtained in the same field, it is not necessary to offset the image, and the processes of steps S330 to S350 are not performed. When the deviation amount is obtained in step S320, the flow is shifted to step S360, and the obtained deviation amount is stored in the storage unit 116 as the fixed vision fine movement amount. After that, the processes of steps S120 to S160 in FIG. 6 are performed using this fixed vision fine movement amount.

In the case of the above-mentioned interlace method, the image to be compared with the reference fundus image in order to obtain the fixed vision fine movement amount can be acquired in about half the time required to acquire the fundus anterior image by the progressive method. Therefore, as compared with the case of the progressive method, the detection of the fixed vision fine movement amount is repeated in a shorter time, and the tracking speed can be increased in this respect as well. However, even in the case of the progressive method, by controlling the fundus tracking only on the imaging device 110 side, the time lag associated with the above-mentioned data transfer and the like can be reduced, and the fundus tracking can be speeded up. In the above-described embodiment, a so-called raster scan is exemplified as a scanning pattern for scanning the illumination light and the measurement light. However, the scanning pattern is not limited to the raster scan, and may include a 3D scan, a radial scan, a cross scan, a circle scan, a Lissajous scan (scanning along a Lissajous curve), and the like. Even when a tomographic image is obtained from these scanning patterns, by controlling the fundus tracking described in the present embodiment, it is possible to reduce the time lag associated with the above-mentioned data transfer and the like, and to speed up the fundus tracking. can.

The present invention is not limited to the contents described in the above-described embodiment, and various modifications and the like can be made within the scope of the claims. Further, an ophthalmic system using an OCT device as an imaging device has been exemplified, but the present invention is not limited thereto. In an ophthalmic system including OCTA, which is generally used for fundus tracking, and SLO using an adaptive optics system, high-speed fundus tracking is required in the same manner as the OCT device. The configuration is applicable. In the case of OCTA, for example, the device configuration is the same as that described in the first embodiment. The difference is that the processing device 120 performs a phase-de-phase calculation between a plurality of tomographic images, and adds a configuration for obtaining a motion contrast indicating a contrast of temporal changes in pixel values. Further, for example, in the flowchart of FIG. 7, it is determined in step S160 whether or not a predetermined number of OCT images have been taken at the same location, and then whether or not a predetermined number of OCT images have been taken at all scheduled scanning positions. Whether or not it will be determined. However, the basic configuration of the photographing device 110 and the processing device 120 does not change.

The OCTA apparatus acquires a plurality of tomographic images from the same position at different times, and acquires the dephase-to-phase value at the same location in these tomographic images as motion contrast data. Then, an OCTA image is generated using the obtained motion contrast data, and the distribution of moving objects and the like are observed. Here, the motion contrast data is a numerical value of the contrast between the tissue having a flow (for example, blood) and the tissue without a flow among the tissue of the subject. In this case, it is not necessary to change the configuration of the OCT device, and a shooting mode for OCTA (OCTA shooting mode) may be provided so that it can be selected. In the OCTA shooting mode, it is desirable to be able to select any of 3D scan, radial scan, cross scan, circle scan, and resage scan other than raster scan. In the OCTA imaging mode, the measurement light is scanned a predetermined number of times at the same position, and motion contrast data is obtained from the obtained predetermined number of tomographic images, and these predetermined number of tomographic images are referred to as clusters. If such a cluster includes one tomographic image with insufficient scanning position correction, it is determined that there is a flow in all tissues between the one tomographic image and the other tomographic images. It ends up. Therefore, if one cluster includes a cluster in which the amount of fixation tremor is determined to be larger than the threshold value, it is desirable to reacquire all tomographic images in that cluster.

In the case of the so-called AO-SLO using the adaptive optics system, a fundus imaging unit composed of the adaptive optics SLO is provided in place of the tomographic image imaging unit 112 in the first embodiment separately from the fundus front image capturing unit 111. .. The AO-SLO is a device that reduces the influence of aberrations caused by optical tissues of the eye such as the cornea and the crystalline lens and enables detailed observation of the eye in a narrower range. It is equipped with an adaptive optics system that corrects the aberration of. In the AO-SLO, similarly to the tomographic image capturing unit 112, the fundus imaging unit captures the fundus image independently of the tomographic image capturing unit 112, and obtains it from the information regarding the image acquired by the fundus front image capturing unit 111. The scanning position of the illumination light is corrected based on the amount of fixed vision fine movement. That is, even in the SLO using the adaptive optics system, the detection of the fixed vision fine movement amount and the feedback control associated therewith are performed in the same manner as in the first embodiment, and therefore, by arranging the same configuration as in the first embodiment. Tracking can be speeded up.

As described above, the ophthalmic system according to the present embodiment includes a photographing device 110 and a processing device (processing device 120) for generating an image. The imaging device 110 includes a first imaging unit (fundus front image imaging unit 111) and a second imaging unit (tomographic image imaging unit 112), and the first imaging unit relates to the first image of the eye to be inspected. The information is acquired, and the information regarding the second image is acquired by the second photographing unit. The information regarding the first image includes, for example, the luminance information used for generating the frontal fundus image. The information about the second image also includes an interference signal used to generate the tomographic image. The photographing device 110 also acquires information regarding the first image (SLO signal detection unit 245), and uses the information to acquire information regarding the amount of movement of the eye to be inspected by the arithmetic circuit 115. Information about this movement includes, for example, the amount of movement of the eye to be inspected, the direction of movement, and the rotation of the eye to be inspected. Then, in the photographing device 110, the correction means (control unit 114) corrects the acquisition position of the information regarding the second image (the scanning position of the measurement light in the OCT or the position of the optical head unit) by using the information regarding the movement. do. The photographing device 110 has a transmitting unit 118 (transmitting means), and the transmitting unit 118 is connected to a receiving unit 125 (receiving means) of the processing device 120 by a communication means. The transmission unit 118 transmits, for example, the above-mentioned luminance information and the interference signal to the reception unit. The receiving unit 125 receives the luminance information and the interference signal. The processing device 120 also has a generation means (image generation unit 121) that generates a fundus frontal image using the received luminance information and generates a tomographic image using the received interference signal. The processing device 120 also has display control means (display control unit 126) for displaying the image generated by the image generation unit 121 on the display means (display unit 130). The second image may be an OCTA image or a fundus frontal image obtained by an SLO having an adaptive optics system.

The calculation circuit 115 described above calculates the amount of movement (fixation fine movement amount) of the eye to be inspected using information on a plurality of frontal images of the fundus. More specifically, the calculation circuit 115 calculates the amount of movement by performing a two-dimensional correlation calculation between information on a plurality of frontal fundus images (a plurality of first images). In this two-dimensional correlation calculation, it corresponds to the number of pixels obtained by reducing the number of pixels of the image (the image corresponding to the frontal image of the fundus of the eye generated by the image generation unit 121) obtained from the information related to the first image. It is advisable to generate a hierarchical image to be used. In this hierarchical image, the arithmetic circuit 115 extracts a pattern used for calculating the movement amount. Then, the amount of deviation between the images obtained from the information on the plurality of first images is obtained by using the coordinates of the pattern in the region including the extracted pattern of the image obtained from the information on the first image, and the amount of movement is obtained. Is calculated. Further, in order to perform more detailed fundus tracking, the two-dimensional correlation calculation may be performed on a sub-pixel basis for the pixels constituting the fundus frontal image.

Further, in the present embodiment, the arithmetic circuit 115 determines whether or not the calculated amount of fixation tremor exceeds the threshold value. The determination result is transmitted to the processing device 120. When it is determined that the calculated fixation tremor amount exceeds the value, the processing device 120 uses the generated tomographic image as an image obtained from the interference signal obtained in response to the luminance information exceeding the threshold value. Can be replaced with the image of. In the present embodiment, the frontal image of the fundus is acquired by the interlace method. The arithmetic circuit 115 generates a field image by synthesizing the information obtained from the columns corresponding to the odd-numbered pixel strings in the frontal image of the fundus of the eye and the information obtained from the columns corresponding to the even-numbered pixel strings. Then, using the generated field image as a reference fundus image using the information related to the first image, the amount of fixation tremor is calculated as the amount of movement of the eye to be inspected. The method of generating the reference fundus image is not limited to this, and either the information obtained from the column corresponding to the odd-numbered pixel string in the frontal image of the fundus or the information obtained from the column corresponding to the even-numbered pixel string. Can also be generated using. That is, the information about the first image used when comparing with the reference fundus image is at least a plurality of luminance values corresponding to a plurality of pixels constituting the first image generated by the image generation unit 121. It consists of a part. More specifically, the amount of movement of the eye to be inspected can be determined by comparing the image information obtained by arranging at least a part of the luminance values acquired as the information about the first image in the corresponding pixels with the reference fundus image. ..

Here, the information regarding the first image is, for example, information acquired in a plurality of cases in which the luminance value and the two-dimensional coordinates correspond to each other, and is obtained by arranging (arranging) the luminance values in the pixels corresponding to the two-dimensional coordinates. It may be an image to be displayed. In the present embodiment, the information regarding the first image is acquired by using a confocal laser scanning ophthalmoscope. Further, the information regarding the second image is acquired by using the OCT apparatus. That is, the photographing device 110 acquires an interference signal by using the return light from the eye to be inspected scanned by the measurement light, and the image generation unit 121 to which the interference signal is sent generates a tomographic image of the fundus of the eye to be inspected. Further, in the present embodiment, the first image generated by the image generation unit 121 is a fundus frontal image. Further, in the present embodiment, USB is used as the communication means, but Gigabit Ethernet (registered trademark) can also be used. Further, a wireless communication means may be used.

In the above-described embodiment, the tomographic image is acquired by raster scan. In the raster scan, for example, the measurement light is scanned in the direction of the scanning line L01 in FIG. 5 (main scanning), and then the irradiation position of the measurement light is scanned (secondary scanning) at the scanning start position at the position of the scanning line L02. , Subsequent scanning that repeats this. As shown in FIG. 7, the correction of the scanning position is performed between one main scan and the next main scan. As a result, the measurement light is scanned so that the scanning lines are arranged as L01 to L20 on the fundus, and an interference signal from a desired position on the fundus can be obtained without excess or deficiency.

Further, in the above-described embodiment, one tomographic image is acquired for one fundus frontal image. However, if the timing of acquiring the frontal fundus image and the timing of acquiring the tomographic image can be synchronized, the number of images in which the other image is an integral multiple may be acquired while one image is acquired. For example, the case where one or two tomographic images are acquired corresponds to the timing of acquiring one frontal fundus image, and in the flowchart of FIG. 7, one or two tomographic images are acquired in step S150. Further, as in the case of OCTA imaging, for example, a plurality of tomographic images are acquired at the same position. If synchronization is not possible, even if fixation tremor is detected during the acquisition of the tomographic image, the scanning position is not corrected during this acquisition, and the scanning position of the measurement light for the next tomographic image acquisition is corrected. It is advisable to make corrections at the timing of. Further, it is also conceivable to acquire a plurality of tomographic images at the same position as in the case of OCTA imaging, for example. In this case, even if fixation tremor is detected while acquiring the tomographic image at the same position, the scanning position is not corrected during the acquisition of the tomographic image from the same position, and the first tomographic image at the next position is not corrected. It is advisable to delay the timing of correction of the scanning position until the start of acquisition of. If synchronization is not possible, synchronization may be performed only at the start of the main shooting, and if correction of the scanning position is required, rescanning may be performed. In that case, the rescan position can be calculated using the elapsed time from the start and the frame rate.

Further, in the above-described embodiment, the scanning laser ophthalmoscope is used as the fundus frontal image capturing unit, but other known image acquisition means can also be used to acquire the fundus frontal image. For example, the fundus front image capturing unit may use a configuration in which the fundus front image is collectively acquired by a two-dimensional sensor. Further, in this case, the two-dimensional sensor may be configured to be built in the photographing device main body, or the digital camera including the two-dimensional sensor and the photographing device main body may be detachably configured. When the digital camera and the main body of the photographing device are detachable, the digital camera and the main body of the photographing device are communicably connected, so that the arithmetic circuit arranged in the main body of the photographing device can provide information on movement. It can be acquired.

[Second Embodiment]
In the first embodiment described above, the fundus tracking is controlled on the imaging device 110 side to speed up the fundus tracking. On the other hand, on the processing device 120 side, a tomographic image is generated from the interference signal obtained by correcting the acquisition position by fundus tracking, and a frontal fundus image is only generated from the luminance information used for fundus tracking. There is. Here, for example, when the amount of fixation tremor is larger than expected, it is possible that even if the fundus tracking is accelerated, the artifacts and the like may remain without being able to deal with it. In the second embodiment, in such a case, when the amount of fixation tremor exceeds the threshold value at which the artifact may remain, specific measures are taken for the portion where the artifact occurs. Hereinafter, the ophthalmic system according to the second embodiment of the present invention will be described in detail with reference to FIGS. 11 to 14. In the following description, configurations exhibiting the same or similar functions as the components described in the first embodiment will be shown in the drawings using the same reference numerals, and the description thereof will be omitted here.

FIG. 11A shows a schematic configuration of the ophthalmic system according to the second embodiment, and FIG. 11B shows a block diagram of the functional configuration of the ophthalmic system. In the second embodiment, in the photographing operation, in addition to the fundus tracking performed in the first embodiment, the first embodiment is to reacquire the tomographic image in consideration of the possibility of occurrence of an artifact on the processing device 2120 side. Different from the form. Therefore, as shown in FIG. 11B, the ophthalmic system according to the second embodiment is different from the processing device 120 in the first embodiment in that the processing device 2120 further includes the image processing unit 2124. In addition to these, as a specific difference in imaging processing, in the present embodiment, two-dimensional correlation calculation is performed using small image data when detecting fundus fixation tremor. Then, by reducing the amount of calculation by this, fundus tracking with higher real-time performance is performed. In addition, the processing device 2120 performs a two-dimensional correlation calculation using large image data, detects large fixation tremors and blinks by tracking, and makes a rescan determination (determination of whether or not to reacquire a tomographic image). )I do. With the above configuration, the feedback control of fundus tracking can be speeded up, and whether or not the tracking has failed is determined by the processing device 2120 by parallel processing, so that a tomographic image with reduced artifacts can be obtained. It has the effect of being able to do it.

The large image data described here corresponds to an amount of image data corresponding to the entire area of the tomographic image composed of M search regions, as shown in FIG. 14, for example. Further, the small image data corresponds to, for example, an amount of image data corresponding to one search area shown in FIG. That is, large image data and small image data are terms that are relatively determined according to whether the number of pixels used as an image is relatively large or small, and do not indicate a specific amount of data. .. In the example described here, the photographing device 110 uses a narrow range image in which the number of pixels is small and the amount of data is relatively small for tracking the fundus, and the processing device 2120 uses the total number of pixels for generating the frontal image of the fundus. A wide range of images is used, in which the amount of data corresponding to is large.

Next, the details of the processing performed at the time of fundus tomography imaging by the ophthalmic system of the present embodiment will be described with reference to the flowchart shown in FIG. In this embodiment as well, as in the first embodiment, the scanning of the illumination light for capturing the frontal fundus image is performed by the interlace method described with reference to FIG. 4 in order to increase the frame rate. In actual fundus photography, when the measurement start button 306 is pressed, the imaging process shown in the flowchart of FIG. 12 is started.

<Step S500>
In step S500, the control unit 114 controls the fundus anterior image capturing unit 111 to acquire a reference fundus image for performing fundus tracking. The storage unit 116 stores the acquired reference fundus image for use when performing fundus tracking. The processing performed at the time of acquiring the reference fundus image is the same as the processing performed in the first embodiment. In the present embodiment, the processing device 2120 also uses the fundus anterior image to determine the suitability of the tomographic image (data acquired by the B scan) obtained by fundus tracking. Therefore, the reference fundus image is also generated by the image generation unit 121 in the processing device 2120. Since the reference fundus image generation process performed by the processing device 120 is the same process as that described in the first embodiment, the description thereof is omitted here.

<Step S510>
In step S510, the arithmetic circuit 115 detects the position change of the frontal image of the fundus with time, and calculates the amount of fixation tremor of the eye to be inspected by obtaining the amount. The details of the calculation operation of fundus fixation tremor will be described later.

<Step S520>
In step S520, the control unit 114 corrects the acquisition position of the tomographic image by changing the position of the scanning line by the amount of fixation microtremor detected in step S510. Specifically, the correction of the acquisition position of the tomographic image is performed by changing the scanning control signal given to the OCT scanning optical system 213 by the control unit 114. In the first embodiment, a threshold value is set in consideration of the amount of fixation tremor when the influence of fixation tremor appears in the tomographic image, and when the amount of fixation tremor exceeds the threshold, the acquisition position is corrected. Is going. However, in the present embodiment, the acquisition position is always corrected according to the calculated amount of fixation tremor regardless of the amount of fixation tremor.

<Step S530>
In step S530, the acquisition of the tomographic image is started in response to the completion of the correction of the tomographic image acquisition position by the control unit 114. Specifically, at the corrected scanning position, scanning of the fundus with the measurement light is started. Then, based on the interference signal acquired by the OCT signal detection unit 218 by this scanning, the tomographic image capturing unit 112 starts acquiring (generating) a tomographic image (B scan image) of the fundus of the eye to be inspected. The generated tomographic image is displayed on the display unit 130 by the processing device 120 in the display format illustrated in FIG. 5, for example.

<Step S540>
In step S540, on the processing device 2120 side, the image processing unit 2124 detects the amount of fixation tremor of the eye to be inspected by detecting the position change of the fundus front image with the passage of time. As the fundus fixation tremor detection operation, the same processing as that described with reference to FIG. 9 in the first embodiment is performed, and thus the description thereof is omitted here.

<Step S550>
In step S550, the image processing unit 2124 determines whether or not to reacquire the tomographic image by rescanning from the result detected in step S540. This determination can be made, for example, from the amount of fixation tremor and the correlation value when the two-dimensional correlation calculation is performed. When the detected amount of fixation tremor exceeds an arbitrary threshold value, it is judged that there is a high possibility that an artifact due to movement has occurred in the tomographic image acquired during that period, and the scanning line obtained from this tomographic image is obtained. Perform a rescan for. Further, when the correlation value of the peak detected in step S540 is lower than an arbitrary threshold value, it can be determined that blinking has occurred. Therefore, the rescan is performed in this case as well.

<Step S560>
In step S560, the image processing unit 2124 transmits the re-imaging information of the tomographic image to the imaging device 110. For example, when a rescan determination is made as a result of the determination in step S550, information regarding the rescan is transmitted from the image processing unit 2124 of the processing device 2120 to the control unit 114 of the photographing device 110. Based on the information, the control unit 114 performs rescan control on the photographing device 110 in a step described later. The information regarding the rescan includes, for example, whether or not to perform the rescan, and if so, the line of the scanning line of the tomographic image acquired while the frontal fundus image generated in step S540 was acquired. Numbers and are exemplified.

In the present embodiment, while the fundus tracking and the acquisition of the tomographic image are executed on the imaging device 110 side, the fixation fine movement amount is obtained on the processing device 2120 side, and the fixation fine movement amount is at a level requiring rescanning. It is judged whether or not there is. A time lag occurs by transmitting the luminance information to the processing apparatus 2120 as described above. Further, while the fundus tracking performed on the imaging device 110 side targets the search area corresponding to the small image data shown in FIG. 14, the fixation device 2120 side targets the entire area of the fundus front image and the amount of fixation tremor. Seeking. Therefore, it takes time for the processing device 2120 to obtain the rescan information based on the fixed vision fine movement amount. However, in the present embodiment, the tomographic image accompanied by the fundus tracking is taken only on the photographing device 110 side, and at the same time, the processing device 2120 side is trying to obtain only the rescan information in parallel with this. As a result, the time for obtaining the rescan information does not affect the time required for acquiring the tomographic image accompanied by the fundus tracking, and as a result, the decrease in the tracking speed as the imaging device can be reduced.

<Step S570>
In step S570, the control unit 114 determines whether or not the measurement (acquisition of a tomographic image) has been completed. Since the tomographic image by OCT has a lot of noise, for example, the tomographic image is acquired a plurality of times for the same scanning line, the acquisition results are added and averaged, and the noise is reduced. Further, as described above, it is also possible to obtain a three-dimensional image (C scan image) of the fundus by acquiring a plurality of tomographic images while shifting the positions of the scanning lines and synthesizing the obtained tomographic images. The end of the measurement is determined by whether or not the acquisition of the tomographic image of a predetermined number of times is completed or the acquisition of the tomographic image from the predetermined area is completed. When the acquisition of the tomographic image is completed, the flow is shifted to step S580 by the control unit 114. If the acquisition is not completed, the control unit 114 shifts the flow to steps S510 and S540, and repeats the subsequent operations until the acquisition is completed a predetermined number of times.

<Step S580>
In step S580, when the rescan information is transmitted to the control unit 114 in step S560, the flow shifts to step S510 and step S540. Then, in these steps, the reacquisition of the tomographic image of the rescanned area or scanning line is started. If there is no information regarding the rescan to reacquire, the shooting operation ends.

(Flowchart of fundus fixation microtremor detection operation)
Next, the fundus fixation tremor detection operation executed in step S510 of FIG. 12 will be described with reference to the flowchart of FIG. In the following description, since the scanning of the illumination light for acquiring the frontal fundus image starts from the L01 line as shown in FIG. 4, a case where an odd number field is used as a reference will be described. In the following example, an offset is not added when the reference fundus image and the image of the odd field are correlated, and an offset is added to the image of the even field when the correlation is obtained with the image of the even field. ..

<Step S700>
When the fundus fixation tremor detection operation in step S510 is started, the control unit 114 starts the operation according to the flowchart of FIG. First, in step S700, the control unit 114 controls the fundus front image capturing unit 111 to start scanning the illumination light (acquisition of the fundus front field image) in order to acquire an image of an odd number field. The arithmetic circuit 115 generates an odd-numbered field image by using the output from the SLO signal detection unit 245 that has obtained the reflected light from the fundus.

In the present embodiment, the field image acquired in step S700 is a field image of a small area obtained by dividing the acquisition area of the original fundus front image. A field image of this small area will be described with reference to FIG. In the present embodiment, as shown in FIG. 14, the arithmetic circuit 115 divides the scan area of the illumination light, which is the acquisition region of the original fundus front image, into M in the vertical direction, for example. Then, for example, regarding the scanning direction of the illumination light, the X direction (horizontal direction of the fundus front image) is the same width as the original fundus front image, and the Y direction (vertical direction) is an image of a region having a width of 1 / M. These images are acquired in order from the th to the Mth search area. The image data in such a search region corresponds to the small image data described above, and the image data obtained from the acquisition region of the original fundus frontal image corresponds to the large image data. The division mode shown here is an example, and may be divided in the X (horizontal direction) or the XY direction, for example. The number of divisions may be determined, for example, according to the number of acquisitions of tomographic images for the same scanning line.

<Step S710>
In step S710, the arithmetic circuit 115 frames the divided field image acquired in step S700, here the image of the odd field in the search area obtained by the division, by the method described in the first embodiment. Frame is done as follows. First, a data area having twice the number of lines of odd-numbered field data is prepared. Next, the data of n lines of odd-numbered field data (n = 1, 2, 3, ..., N / 2M: N is the total number of scanning lines, M is the number of divisions) is copied to each of the 2n-1 lines in the data area. .. Further, the data of the 2n-1 line in the data area is copied to the 2n line respectively. As a result, the scan line data of the odd field is duplicated. Here, since the data of the scan line of the odd field data is written twice on the scan line of the data area for framing the data, the expression "copy" is used. From the above, it is possible to prepare image data having twice the number of lines (corresponding to frame data) of the field data and having the same data for the odd-numbered line and the next even-numbered line for use in the divided field image.

<Step S720>
In step S720, the calculation circuit 115 performs a two-dimensional correlation calculation on the reference fundus image acquired in step S700 with the fundus front image of the search region framed in step S710. However, as the reference fundus image, in step S700, a part of the reference fundus image, which is a region corresponding to the search region framed in step S710, is used. Since the correlation calculation here is a correlation calculation between frame data, it is considered that there is no variation in the X direction in pixel units, but in the Y direction, the displacement amount in one scanning line unit is obtained. Further, in the two-dimensional correlation calculation, the displacement amount in sub-pixel units is obtained according to the method described in step S220 of the flowchart shown in FIG. 7 of the first embodiment.

<Step S730>
In step S730, the arithmetic circuit 115 determines whether or not the divided field image used in step S700 is an odd-numbered field image. In the case of an odd-numbered field image, the control unit 114 shifts the flow to step S740. If not, that is, if the acquired image is an even field image, the flow proceeds to step S750.

<Step S740>
Since the displacement amount obtained in step S720 is calculated based on the image of the odd-numbered field, it is necessary to take this into consideration. In the case of an odd-numbered field image, in step S740, the arithmetic circuit 115 does not add an offset in the Y-axis direction to the framed image data (ie, offset 0). The control unit 114 maintains the image data as it is and shifts the flow to step S760.

<Step S750>
When the displacement amount obtained in step S720 is calculated based on the image of the even field, it is necessary to take this into consideration. Therefore, in the case of an even-numbered field image, in step S750, the arithmetic circuit 115 adds an offset of 1 in the Y-axis direction to the framed image data. Then, the process proceeds to step S760. This offset of 1 takes into consideration the difference in position between the odd-numbered field and the even-numbered field in the 2n-line data constituting the framed data area.

<Step S760>
By the above operation, the amount of displacement between the reference fundus image and the frontal image of the fundus acquired in step S700, that is, the amount of fixation tremor of the eye to be inspected can be obtained. In step S760, the control unit 114 stores the fixation fine movement amount obtained by the arithmetic circuit 115 in the storage unit 116. With the above, the detection operation of fixation tremor is completed.

In the above description, an example in which an odd number field is used as a reference is shown, but an even number field may be used as a reference. In that case, no offset is added when the reference fundus image and the field image obtained by framing the even-numbered field image are correlated. On the other hand, when the field image obtained by framing the odd-numbered field image and the reference fundus image are correlated, an offset (for example, an offset of -1 in the Y-axis direction) is added.

In this embodiment, an example of synthesizing a frame image as a reference fundus image from an odd-numbered field image and an even-numbered field image is shown. However, the reference fundus image may be obtained from a field image that is not composited. For example, an odd-numbered field image and an even-numbered field image can be acquired, the sharpness and the average luminance value can be evaluated by the image evaluation unit 123, and the one with the higher evaluation can be used as a reference fundus image. When the image of the odd-numbered field is used as the reference fundus image, the offset is 0 when the odd-numbered field and the image are correlated. Further, when correlating with an even-numbered field image, an offset of 0.5 is added in the Y direction. When the even-numbered field image is used as the reference fundus image, an offset of -0.5 is added in the Y direction to correlate with the odd-numbered field image, and an offset of 0 is added to correlate with the even-numbered field image. And. The unit of this offset is the scanning line unit in the interlaced field. Correlation is done on a sub-pixel basis. In addition, when the image of the odd-numbered field is used as the reference fundus image, only the image obtained from the odd-numbered field is correlated with the image of the front of the fundus, and when the image of the even-numbered field is used as the reference fundus image, it is obtained from the even-numbered field. It can also be configured to correlate with only the images.

In the present embodiment, the photographing apparatus 110 reduces the influence of fixation tremor by performing the above-mentioned fundus tracking in order to scan a desired position on the fundus with the measurement light. Further, in the present embodiment, separately from the fundus tracking which requires high speed, the processing device 2120 determines whether or not the amount of fixation tremor at the time of acquiring a tomographic image is larger than a predetermined threshold value. Then, when a large movement of the fundus, which is an artifact, is detected in generating an image such as fixation tremor, rescanning is automatically performed at the place where the artifact occurs. In the first embodiment, the imaging device 110 determines whether or not the amount of fixation tremor is larger than a predetermined threshold value, and if it is larger than the threshold value, reacquisition is performed immediately. The time required for acquisition is reduced. On the other hand, in the present embodiment, the processing apparatus 2120 also compares the amount of fixation tremor for reacquisition with a predetermined threshold value. As in the present embodiment, by obtaining the fixed vision fine movement amount using the detailed image generated on the processing device 2120 side, it is possible to assist in determining the necessity of reacquisition with higher accuracy.

Further, in the present embodiment, in order to perform fundus tracking at a higher speed, a partial frontal image of the fundus, which is small data, is used as a field image for fundus tracking. The processing device 2120 uses a frontal fundus image in the entire area consisting of large image data to perform highly accurate tracking and perform a rescan determination. As a result, even when a relatively large movement per unit time occurs on the fundus of the eye to be inspected, the distortion caused by this movement can be reduced by the tomographic image obtained by the rescan.

In the above-mentioned imaging process of the fundus tomographic image, information on one rescan for each acquisition of the tomographic image (information on whether or not to perform the rescan and, if so, which scanning line to perform). Is getting. However, depending on the number of search areas and the speed required to acquire one tomographic image, it is assumed that a plurality of tomographic images may be obtained while obtaining information on one rescan. For example, the imaging device 110 is controlled so that one tomographic image can be obtained according to one of the search areas in FIG. 14, and a number of tomographic images corresponding to the number of search areas can be obtained from a plurality of scanning lines. There is. In such a case, M tomographic images are acquired from M scanning lines, but the processing device 2120 occurs while acquiring M tomographic images using one frontal fundus image of the entire area. Find the amount of fixed vision tremor. Then, when it is estimated that an artifact is generated from the amount of fixation tremor, it is advisable to perform reacquisition of M tomographic images with the M scanning lines as the target of rescanning.

Further, when performing such a process, it is preferable to provide a step after step S530 to determine whether or not the tomographic image has been acquired a predetermined number of times by the control unit 114. For example, in the case of a process for generating an averaging image, if the acquisition of a predetermined number of tomographic images for obtaining the averaging image is completed, the control unit 114 shifts the flow to step S540. If a predetermined number of tomographic images have not been acquired yet, the control unit 114 returns the flow to step S510, and repeats the acquisition position correction process and the tomographic image acquisition process again. Further, for example, when the present embodiment is applied in OCTA, tomographic images are acquired a predetermined number of times by repeatedly scanning the same location so that blood flow and the like can be discriminated. Further, when a three-dimensional tomographic image is obtained without repeatedly scanning the same location, the number of tomographic images corresponding to a predetermined number of scanning lines is set to a predetermined number or the number of search areas. Set. By matching the timing at which the tomographic image is acquired a predetermined number of times with the timing at which the information regarding the rescan is transmitted in step S560, the speed of fundus tracking can be increased.

With the above configuration, in the present embodiment, the feedback control of fundus tracking can be increased in speed. Further, whether or not the fundus tracking has failed is determined by the processing device 2120 by parallel processing, and the tomographic image with the reduced artifacts is obtained by reacquiring the tomographic image for the scanning line for which the fundus tracking has failed. be able to. Therefore, in the present embodiment, when a movement (such as a flick movement among the fixed vision fine movements) in which the movement per unit time is relatively large among the movements of the eye to be inspected occurs, a tomographic image acquired at the timing of this movement occurs. Can be reacquired as appropriate. That is, according to the present embodiment, it is possible to shorten the time required for fundus tracking and to take a tomographic image corresponding to a large movement of the eye to be inspected.

The present invention is not limited to the contents described in the above-described embodiment, and various modifications and the like can be made within the scope of the claims. Moreover, although the OCT apparatus was used as an ophthalmic system, the present invention is not limited to this. In ophthalmic systems such as OCTA where fundus tracking is generally performed and SLO using adaptive optics, speeding up of fundus tracking is required in the same manner as in OCT devices. Therefore, these ophthalmologic systems are also described above. The configuration is applicable. In the case of OCTA, for example, the device configuration is the same as that described in the first embodiment. The difference is that the processing device 120 performs a phase-de-phase calculation between a plurality of tomographic images, and adds a configuration for obtaining a motion contrast indicating a contrast of temporal changes in pixel values. However, the basic configuration of the photographing device 110 and the processing device 120 does not change. In the case of the so-called AO-SLO using the adaptive optics system, a fundus imaging unit composed of the adaptive optics SLO is provided in place of the tomographic image imaging unit 112 in the first embodiment separately from the fundus front image capturing unit 111. .. Similar to the tomographic image capturing unit 112, the fundus imaging unit captures the fundus image independently of the tomographic image capturing unit 112, and the amount of fixation tremor obtained from the information about the image acquired by the fundus front image capturing unit 111. Based on this, the scanning position of the illumination light is corrected. That is, even in the SLO using the adaptive optics system, the detection of the fixed vision fine movement amount and the feedback control associated therewith are performed in the same manner as in the first embodiment, and therefore, by arranging the same configuration as in the first embodiment. Tracking can be speeded up.

As described above, in the present embodiment, the processing device (processing device 2120) is a means (image processing unit 2124) for calculating the movement amount (fixation fine movement amount) based on the fundus front image of the eye to be inspected using the fundus front image. ). When the movement amount based on the calculated frontal image of the fundus exceeds the threshold value set by the processing device 2120, the photographing device 110 in the present embodiment corresponds to the interference signal or income corresponding to the frontal image of the fundus determined to exceed the threshold value. Acquire the interference signal in the area again. In the present embodiment, the interference signal is acquired again after all the interference signals for generating the tomographic image to be initially acquired are acquired. Further, the photographing device 110 divides the acquisition range of the fundus front image into a plurality of ranges, and corrects the acquisition position of the interference signal based on the luminance information obtained from the divided ranges.

[Third Embodiment]
In the second embodiment described above, in parallel with the processing related to fundus tracking performed on the imaging device 110 side, detailed and relatively time-consuming fixation tremor detection processing is performed on the processing device 2120 side. There is. Then, when the amount of fixation tremor that is likely to cause an artifact is calculated in the tomographic image acquired by the processing device 2120, the tomographic image that may have the artifact is reacquired after all the tomographic images are acquired. I'm supposed to do it. When such a rescan is performed, since a series of tomographic images are continuously acquired, fundus tracking on the imaging device 110 side can be easily performed, but until the start of acquisition of the reacquired tomographic image. It takes time.

On the other hand, in the third embodiment, only the rescan control method is different from that of the second embodiment. Specifically, the rescan information regarding the tomographic image is obtained at substantially the same timing as the timing at which the acquisition of the tomographic image from a certain scanning line is completed. That is, it differs from the second embodiment in steps S570 and S580 shown in FIG. In the following, only the part of the processing different from the second embodiment will be described. In the following description, each component in the third embodiment is the same as the component described in the second embodiment, and is different only in the shooting operation. Therefore, the details of the processing performed at the time of taking the tomographic image according to the present embodiment will be described with reference to the flowchart of FIG. In each process of the flowchart shown in FIG. 15, the same process as each process described in the flowchart of FIG. 12 will be shown in the figure using the same reference numerals, and the description thereof will be omitted here.

<Step S800>
When the tomographic image is acquired in step S530 and the information regarding the rescan information is transmitted in step S560, the flow is shifted to step S800 by the control unit 114. In step S800, when the line number of the B scan described above is sent as the information regarding the rescan in step S560, the flow is shifted to step S510 and step S540 by the control unit 114. Then, in these steps, the processing of acquiring the tomographic image in the rescanned area (scanning line) and detecting the amount of fixation tremor is started. That is, if there is rescan information, the acquisition of the tomographic image from the rescan range is immediately started. If there is no rescan information, the control unit 114 shifts the flow to step S810.

<Step S810>
In step S810, the control unit 114 determines whether or not the measurement (acquisition of a tomographic image) has been completed. Since the tomographic image by OCT has a lot of noise, for example, the tomographic image is acquired a plurality of times for the same scanning line, the acquisition results are added and averaged, and the noise is reduced. Further, as described above, a three-dimensional image (C scan image) of the fundus can be obtained by acquiring a plurality of tomographic images while shifting the positions of the scanning lines and synthesizing the obtained data. The end of the measurement is determined by whether or not the acquisition of the tomographic image of a predetermined number of times is completed or the acquisition of the tomographic image from the predetermined area is completed. When the acquisition of the tomographic image is completed, the shooting operation is completed. If the acquisition is not completed in step S810, the control unit 114 shifts the flow to steps S510 and S540, and repeats the above operation until the acquisition is completed a predetermined number of times. That is, in the present embodiment, the re-acquisition of the interference signal is performed in response to the determination that the amount of movement based on the frontal image of the fundus exceeds the threshold value determined by the processing device.

With the above configuration, in the present embodiment, the feedback control of fundus tracking can be increased in speed. Further, whether or not the fundus tracking has failed is determined by the processing device 2120 in parallel processing, so that a tomographic image with reduced artifacts can be obtained. Further, when rescanning is required, acquisition of a tomographic image in the range to be rescanned can be started immediately.

[Other Embodiments]
In the above-described embodiment, an OCT device is used as an example to describe a case where a tomographic image of the fundus of the eye to be inspected is acquired and tracking is performed by the photographing device using the luminance information for obtaining a frontal image of the fundus. However, the OCT apparatus can target not only the fundus but also the anterior segment of the eye and the vitreous body, for example. In this case, for example, in calculating the amount of movement used in tracking when obtaining a tomographic image of the anterior segment, the front surface of the anterior segment obtained by using not only the scanning laser ophthalmoscope described above but also an anterior segment camera or the like. Information about the image may be used. Therefore, the information regarding the first image is not limited to the scanning laser ophthalmoscope illustrated as long as the amount of movement of the eye to be inspected for tracking can be obtained, and is not limited to the information regarding the fundus image. Further, as the information regarding the second image, not only the interference signal from the fundus of the eye by the OCT device or the AO-OCT device but also the interference signal obtained from the anterior segment of the eye or the vitreous body can be used. Further, as the information regarding the second image, the luminance information obtained by AO-SLO from a portion other than the fundus of the eye to be inspected, such as the anterior segment of the eye, can also be used. Further, in each of the above-described embodiments, the present invention has been realized as an ophthalmic system including a photographing device and an image generating device, but the embodiment of the present invention is not limited to the ophthalmic system. For example, the present invention can take an embodiment as a device included in the ophthalmic system, an operating method of the device, a program, a storage medium, or the like. In addition, the present invention can also take an embodiment as an imaging device used in the ophthalmic system described in the above-described embodiment. The imaging device is connected to a processing device (processing device 120) by a communication means, and the processing device generates an image of the front of the fundus from the luminance information and a tomographic image from the interference signal. The imaging device acquires brightness information (SLO signal detection unit 245), calculates the amount of movement of the eye to be inspected by the arithmetic circuit 115 using the information, and uses the calculated movement amount to acquire the interference signal acquisition position (SLO signal detection unit 245). The scanning position of the measurement light in OCT) is corrected.

The OCT apparatus may include a time domain OCT (TD-OCT) apparatus and a Fourier domain OCT (FD-OCT) apparatus. Further, the Fourier domain OCT apparatus may include a spectral domain OCT (SD-OCT) apparatus and a wavelength sweep type OCT (SS-OCT) apparatus. Further, the OCT apparatus may include a Line-OCT apparatus (or SS-Line-OCT apparatus) using line light. Further, the OCT apparatus may include a Full Field-OCT apparatus (or SS-Full Field-OCT apparatus) using area light. In addition, the OCT device may include a Doppler-OCT device. Further, the SLO device and the OCT device may include a wave surface compensation SLO (AO-SLO) device using a wave surface compensation optical system, a wave surface compensation OCT (AO-OCT) device, and the like. Further, the SLO device and the OCT device may include a polarized SLO (PS-SLO) device, a polarized OCT (PS-OCT) device, and the like for visualizing information on polarization phase difference and polarization elimination. Further, the SLO device and the OCT device may include a pathological microscope SLO device, a pathological microscope OCT device, and the like. Further, the SLO device and the OCT device may include a handheld type SLO device, a handheld type OCT device, and the like. Further, the SLO device and the OCT device may include a catheter SLO device, a catheter OCT device and the like. Further, the SLO device and the OCT device may include a head-mounted SLO device, a head-mounted OCT device, and the like. Further, the SLO device and the OCT device may have a structure in which the shooting angle of view can be changed by a configuration capable of optical scaling. Further, the SLO device can acquire a color image or a fluorescence image by using each of the RGB light sources and having a configuration in which one light receiving element receives time-divisionally or a plurality of light receiving elements simultaneously receive light. May be good.

In the above-described embodiment, the correction of the acquisition position of the interference signal is performed by controlling the OCT scanning optical system to correct the irradiation position of the measurement light. However, the correction of the irradiation position is performed not only by controlling the OCT scanning optical system, but also by controlling the drive system 117 by the control unit 114 and moving the optical head unit three-dimensionally relative to the eye 100 to be inspected. You may go. Further, the correction of the irradiation position may be performed by moving the face receiving portion 108 three-dimensionally relative to the optical head portion. Further, both the driving of the optical head portion and the driving of the face receiving portion may be performed, the driving of the optical head portion includes a part of the movement in the XYZ direction, and the driving of the face receiving portion remains in the XYZ. May include movement of. As described above, these drives may be any drive as long as they are drives of an optical member that changes the positional relationship between the optical head portion and the eye to be inspected. That is, the correction of the irradiation position may be any configuration as long as it corrects the acquisition position of the information regarding the second image by changing the positional relationship between the optical head portion and the eye to be inspected.

The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by the processing to be performed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

110: 1110: Imaging device, 114: Control unit, 115: Arithmetic circuit, 116: Storage unit, 120, 1120, 2120: Processing device, 121: Image generation unit, 122: Storage unit, 123: Image evaluation unit, 2124: Image processing unit

Claims (21)

An arithmetic circuit for acquiring information on the movement of the eye to be inspected using the information on the first image of the eye to be inspected, and a position for acquiring information on the second image of the eye to be inspected using the acquired information on the movement of the eye to be inspected. An imaging device including a correction means for correction, a transmission means for transmitting information regarding the first image and information regarding the second image, and a photographing device.
A first image is generated by using the receiving means which is connected to the photographing device by a communication means and receives the information about the first image and the information about the second image and the information about the received first image. Then, a generation means for generating the second image using the information about the received second image, and a display control for displaying the generated first image and the generated second image on the display means. Processing equipment including means and
Ophthalmic system with. The ophthalmic system according to claim 1, wherein the calculation circuit acquires information on the movement by performing a two-dimensional correlation calculation between a plurality of information on the first image. In the two-dimensional correlation calculation, a pattern used for acquiring information on the movement is extracted using a hierarchical image obtained by reducing the number of pixels of the image obtained from the information on the first image, and the first image is described. By a coarse-dense search method for determining the amount of deviation between images obtained from a plurality of information on the first image using the coordinates of the pattern in the region including the extracted pattern of the image obtained from the information on the image. The ophthalmic system according to claim 2, which obtains information on movement. The ophthalmic system according to claim 3, wherein the two-dimensional correlation calculation is performed on a sub-pixel basis for the pixels constituting the first image. The arithmetic circuit determines whether or not the movement amount, which is information about the movement, exceeds the threshold value, and determines whether or not the movement amount exceeds the threshold value.
When it is determined that the movement amount exceeds the threshold value, the photographing apparatus reacquires the information regarding the second image corresponding to the information regarding the first image in which the movement amount exceeds the threshold value. The ophthalmic system according to any one of 4. The processing device acquires a movement amount based on the first image of the eye to be inspected using the first image, and determines whether or not the movement amount based on the acquired first image exceeds a threshold value. death,
When the movement amount based on the acquired first image exceeds the threshold value, the photographing device claims to reacquire the information regarding the second image corresponding to the first image in which the movement amount exceeds the threshold value. Item 3. The ophthalmic system according to any one of Items 1 to 5. The ophthalmic system according to claim 6, wherein the reacquisition of the information regarding the second image is performed after the photographing apparatus acquires the information regarding the second image to be acquired. The sixth aspect of claim 6 is that the re-acquisition of the information regarding the second image is performed in response to the determination that the movement amount based on the acquired first image exceeds the threshold value determined by the processing apparatus. The described ophthalmic system. The information about the first image is obtained by an interlaced method.
The arithmetic circuit has a field image obtained by synthesizing information obtained from a column corresponding to an odd-numbered pixel string in the first image and information obtained from a column corresponding to an even-numbered pixel string. The ophthalmic system according to any one of claims 1 to 8, wherein the information related to the movement is acquired by using it as the information related to the image of 1. The information about the first image is obtained by an interlaced method.
The arithmetic circuit relates to a field image generated from information obtained from a column corresponding to an odd-numbered pixel string of the first image or information obtained from a column corresponding to an even-numbered pixel string with respect to the first image. The ophthalmic system according to any one of claims 1 to 8, wherein the information regarding the movement is acquired by using it as information. The photographing apparatus divides the acquisition range of the first image into a plurality of ranges, and obtains the acquisition position of the information regarding the second image based on the information regarding the first image obtained from the divided ranges. The ophthalmic system according to any one of claims 1 to 10 to be amended. The correction means changes the positional relationship between the eye to be inspected and an optical head portion including at least a part of an optical system for irradiating the eye to be inspected with measurement light and detecting return light from the eye to be inspected. Alternatively, the ophthalmic system according to any one of claims 1 to 11, wherein the scanning optical system that scans the measurement light in the eye to be inspected corrects the acquisition position of the information regarding the second image. The imaging device further includes a first imaging unit that acquires information about the first image from the eye to be inspected, and a second imaging unit that acquires information about the second image from the eye to be inspected. The ophthalmic system according to any one of claims 1 to 12. The ophthalmic system according to claim 13, wherein the first imaging unit acquires information regarding the first image by using a confocal laser scanning ophthalmoscope or a two-dimensional sensor. The ophthalmic system according to claim 13 or 14, wherein the second imaging unit acquires information about the second image by using an OCT apparatus. The information regarding the first image is at least a part of a plurality of luminance values corresponding to the plurality of pixels constituting the first image.
Claims 1 to 15 for the arithmetic circuit to acquire information on the movement by using an image obtained by arranging at least a part of the plurality of luminance values acquired as information on the first image on corresponding pixels. The ophthalmic system according to any one of the above. The ophthalmic system according to any one of claims 1 to 16, wherein the first image is a frontal image of the fundus of the eye to be inspected, and the second image is a tomographic image of the fundus of the eye to be inspected. The ophthalmic system according to any one of claims 1 to 17, wherein the communication means includes USB or Gigabit Ethernet. A first image is generated using the receiving means for receiving the information regarding the first image of the eye to be inspected and the information regarding the second image of the eye to be inspected and the information regarding the received first image, and the first image is received. It includes a generation means for generating a second image using information about the second image, and a display control means for causing the display means to display the generated first image and the generated second image. An imaging device that is connected to a processing device by a communication means and constitutes an ophthalmic system together with the processing device.
An arithmetic circuit for acquiring information on the movement of the eye to be inspected using the information on the first image of the eye to be inspected, and a position for acquiring information on the second image of the eye to be inspected using the acquired information on the movement of the eye to be inspected. The correction means for correcting the above, the transmission means for transmitting the information regarding the first image and the information regarding the second image, and the transmission means.
A shooting device equipped with. In the photographing apparatus, the information regarding the movement of the eye to be inspected is acquired using the information regarding the first image of the eye to be inspected, and the acquisition position of the information regarding the second image of the eye to be inspected using the acquired information regarding the movement of the eye to be inspected. Is corrected, and the information regarding the first image and the information regarding the second image are transmitted.
In a processing device connected to the photographing device by a communication means, information on the first image and information on the second image are received, and the first image is displayed using the information on the received first image. A second image is generated by using the information about the generated second image and the received second image, and the generated first image and the generated second image are displayed on the display means.
How to operate an ophthalmic system, including. A program that, when executed by a processor, causes the processor to perform each step of the method of operating an ophthalmic system according to claim 20.

Images