WO2016136926A1 - 断層像撮影装置 - Google Patents
断層像撮影装置 Download PDFInfo
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- WO2016136926A1 WO2016136926A1 PCT/JP2016/055750 JP2016055750W WO2016136926A1 WO 2016136926 A1 WO2016136926 A1 WO 2016136926A1 JP 2016055750 W JP2016055750 W JP 2016055750W WO 2016136926 A1 WO2016136926 A1 WO 2016136926A1
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- 238000005259 measurement Methods 0.000 claims abstract description 32
- 238000012545 processing Methods 0.000 claims abstract description 19
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- 238000005070 sampling Methods 0.000 description 48
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- 238000012014 optical coherence tomography Methods 0.000 description 3
- 239000013307 optical fiber Substances 0.000 description 3
- 210000004220 fundus oculi Anatomy 0.000 description 2
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- 210000004204 blood vessel Anatomy 0.000 description 1
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- 230000004424 eye movement Effects 0.000 description 1
- 230000012447 hatching Effects 0.000 description 1
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- 230000004660 morphological change Effects 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
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- A—HUMAN NECESSITIES
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- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
- A61B3/10—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
- A61B3/102—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for optical coherence tomography [OCT]
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- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
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Definitions
- the present invention relates to a tomographic imaging apparatus that forms a tomographic image of a target object based on interference light generated by superimposing measurement light reflected by the target object and reference light reflected by the reference object.
- a tomographic imaging apparatus using optical interference called OCT (Optical Coherence Tomography) for capturing a tomographic image of the fundus
- OCT Optical Coherence Tomography
- a tomographic image (B-scan image) in the xz direction can be acquired with the left-right direction of the fundus in the x direction, the vertical direction in the y direction, and the depth in the z direction.
- general OCT imaging for example, a tomographic image is captured at a speed of 40 images / second, and a group of 100 or more retinal tomographic images can be acquired by one examination (imaging of a part of the retina).
- Patent Document 1 discloses a technique for generating a tomographic image with less noise by adding and averaging the entire photographed two-dimensional tomographic image.
- Patent Document 2 in order to avoid distortion of tomographic images due to the influence of fixation microtremors, it is required to measure as fast as possible.
- Patent Document 2 in order to shorten the time required for measurement, a plurality of measurement light beams are irradiated with the measurement area slightly shifted and scanned in the same direction, and the obtained two-dimensional tomographic images are subjected to an averaging process.
- a technique for generating a tomographic image with less noise is disclosed.
- Patent Document 1 and Patent Document 2 even if a plurality of images are averaged to generate a high-quality image suitable for interpretation, a finer image than the original plurality of images can be obtained. I can't.
- the present invention has been made in view of such a point, and an object thereof is to provide a tomographic imaging apparatus capable of obtaining a high-quality and high-density interpretation image suitable for interpretation.
- the present invention provides a tomographic imaging means for scanning a tomographic image of the fundus of the subject's eye by scanning measurement light on the fundus of the subject's eye, and a scanning direction of the image of the photographed tomographic image.
- a tomographic imaging apparatus comprising an image processing means for generating a new tomographic image by compressing the first tomographic image (Invention 1).
- the tomographic imaging means scans a tomographic image of the fundus of the eye to be examined by scanning at a second scanning interval that is narrower than the first scanning interval, and the image processing means
- the tomographic image captured at the second scan interval is compressed in the scanning direction to generate a new tomographic image, and the measurement width in the scanning direction of the new tomographic image is scanned at the first scan interval. It is preferable that the width of the image corresponds to the measurement width in the scanning direction of the tomographic image obtained (Invention 2).
- the number of A-scan images constituting the image is larger than the tomographic image obtained by scanning the region at a predetermined scan interval (first scan interval), resulting in a high-density tomographic image.
- the measurement width in the scanning direction of the new tomographic image is equal to the predetermined scanning interval (first Tomograms obtained by scanning at a predetermined scan interval (first scan interval) by generating a tomographic image having a measurement width corresponding to the measurement width in the scanning direction.
- first Tomograms obtained by scanning at a predetermined scan interval (first scan interval)
- second scan interval a predetermined scan interval
- image compression is generally used to reduce the capacity of image data, but compression in the present invention is not limited to such meaning, and only the size of a specific direction of an image is reduced. It is also a concept including making a plurality of images into one image by addition averaging processing, making a plurality of images into one image by filter processing, selecting one image from a plurality of images, and the like.
- the image processing means compresses the A scan image constituting the tomographic image taken at the second scan interval in the scanning direction every n times, and the compressed A It is preferable to combine the scanned images in the scanning direction to generate the new tomographic image (Invention 3).
- each of the compressed A-scan images may be generated by averaging the n A-scan images in the scanning direction (Invention 4),
- Each of the A scan images may be generated by filtering n A scan images (invention 5).
- the second scan interval is preferably 1 / n of the first scan interval (Invention 6).
- the tomographic imaging apparatus of the present invention it is possible to obtain a high-quality and high-density interpretation image suitable for interpretation.
- FIG. 1 is an optical diagram showing an overall configuration of a tomographic imaging apparatus according to an embodiment of the present invention. It is explanatory drawing which showed the concept of the high-density scan and image compression which are implemented in the embodiment. It is explanatory drawing which showed the concept of the high-density scanning and image compression implemented in another embodiment. It is explanatory drawing which contrasted the method of obtaining the image for interpretation by the conventional addition average, and the method of obtaining the image for interpretation by the high-density scan and image compression of this invention. It is a conceptual diagram explaining another embodiment of the image compression of this invention. It is a conceptual diagram explaining another embodiment of the image compression of this invention. It is a conceptual diagram explaining another embodiment of the image compression of this invention.
- the tomographic imaging apparatus uses the fundus of the eye E to be imaged as an object to be imaged, and captures a tomographic image of a desired region of the fundus by raster scanning.
- a portion denoted by reference numeral 10 is a demultiplexing / combining optical system. This optical system emits light having a wavelength of 700 nm to 1100 nm and a temporal coherence length of about several ⁇ m to several tens of ⁇ m, for example, a superluminescent diode.
- a broadband low-coherence light source 11 made of (SLD) is provided.
- the amount of light of the low coherence light generated by the low coherence light source 11 is adjusted through the light amount adjustment mechanism 12 and is incident on the optical coupler 13 through the optical fiber 13a.
- the beam splitter 20 To the beam splitter 20. In addition, you may make it branch and multiplex using an optical circulator instead of the optical coupler 13.
- the light incident on the beam splitter 20 is divided into reference light and measurement light.
- the measurement light enters the focus lens 31 and the measurement light is focused on the fundus of the eye E.
- the measurement light focused on the fundus is reflected by the mirror 32, passes through the lens 33, and is scanned in an arbitrary direction by the x-axis scanning mirror (galvano mirror) 34 and the y-axis scanning mirror (galvano mirror) 35.
- the measurement light scanned by the x-axis and y-axis scanning mirrors 34 and 35 passes through the scan lens 36, is reflected by the dichroic mirror 37, passes through the objective lens 38 and enters the fundus oculi, and the fundus is measured by the measurement light.
- the measurement light reflected from the fundus returns to the beam splitter 20 by reversing the above path.
- the focus lens 31, mirror 32, lens 33, x-axis scanning mirror 34, y-axis scanning mirror 35, scan lens 36, dichroic mirror 37, and objective lens 38 after the beam splitter 20 are tomographic images.
- a measurement optical system 30 of the photographing apparatus is configured. This measurement optical system is provided with optical components such as a mirror and a lens as appropriate in addition to the illustrated optical components, but is omitted in order to avoid complexity.
- the reference light divided by the beam splitter 20 is reflected by the mirror 41 and then passes through the objective lens dispersion compensation glass 42 and the lenses 43 and 44. After that, the light is reflected by the mirror 45 and passes through the eye dispersion compensation glass 50 that compensates the refractive index dispersion of the eye E to be examined. Then, the light is reflected by the dichroic mirror 46 to adjust the condenser lens 47 and the amount of light. It passes through the variable aperture 48 and reaches the reference mirror 49. In order to adjust the optical path length, the condensing lens 47, the variable aperture 48, and the reference mirror 49 move together in the optical axis direction as shown by a double arrow in FIG. The reference light reflected by the reference mirror 49 returns to the beam splitter 20 along the above optical path.
- a reference optical system 40 of the tomographic imaging apparatus is configured.
- This reference optical system is provided with optical components such as a mirror and a lens as appropriate in addition to the illustrated optical components, but is omitted in order to avoid complications.
- the measurement light and the reference light that have returned to the beam splitter 20 are superimposed and become interference light, which passes through the collimating lens 14, the optical fiber 13b, and the optical coupler 13 and enters the spectroscope 16 via the optical fiber 13c.
- the spectroscope 16 includes a diffraction grating 16a, an imaging lens 16b, a line sensor 16c, and the like.
- the interference light is split into a spectrum corresponding to the wavelength of the low coherence light by the diffraction grating 16a and is lined by the imaging lens 16b. An image is formed on the sensor 16c.
- the signal from the line sensor 16c is subjected to signal processing including Fourier transform in the tomographic image generation means 18 realized by the CPU of the computer 17 or the like, and a depth signal indicating information in the depth direction (z direction) of the fundus is generated. Is done. Since the depth signal (A scan image) at the sampling time is obtained by the interference light at each sampling time of the fundus scan, when one scan is completed, the Z direction image (A scan image) along the scan direction is obtained. A two-dimensional tomographic image (B-scan image) can be generated.
- the computer 17 has a function as an image processing means 19 for generating a new tomographic image by compressing the generated tomographic image in the scanning direction in addition to generating a two-dimensional tomographic image by the tomographic image generating means 18.
- FIG. 2 is an explanatory diagram showing the concept of high-density scanning and image compression performed in the present embodiment.
- a tomographic image of the fundus is acquired by high-density scanning and image processing is performed.
- the process of performing is schematically illustrated. 2 and 3, the fundus 100 corresponds to the fundus of the eye E to be examined in FIG. 1, the y-axis scanning mirror 35 is fixed, and the x-axis scanning mirror 34 is the same as viewed in the Y direction of the fundus. Are scanned in the X direction (horizontal direction).
- the predetermined region 100a of the fundus 100 as shown in (a) is scanned across the width D in the X direction (horizontal direction) at a predetermined scanning speed S H, the scan line is shown by a dotted line .
- the predetermined scanning speed S H a standard rate of scan lines is scanned in the X direction when a tomographic image of the normal fundus, in this embodiment, for example, when the scan width D is 5 mm, the width The speed of the scan line when D is scanned over about 0.01 to 0.02 seconds.
- This tomographic image is called an A-scan image, and shows an image of the fundus in the Z direction (depth direction) at the position of the scan line at each sampling time point.
- the length of the difference in position in the B scan direction is the scan interval.
- the A scan image has a width of 1 pixel in the X direction and 10 pixels in the Z direction.
- the width and length of the A-scan image are illustrative and are not limited to this example.
- FIG. 2B shows the A scan images A1, A2,... At the sampling times t1, t2,.
- the A scan image A10 at the fundus position ⁇ of the scan line at the time point t10 and the A scan image A20 at the fundus position ⁇ of the scan line at the sampling time point t20 are illustrated by hatching.
- Each acquired A-scan image is stored in a storage unit (not shown) in the computer 17 with corresponding pixels.
- a scan images A21 to A40 obtained by scanning the same part as obtained at the sampling time t1 to t20 are obtained at the sampling time t21 to 40, and are respectively stored in the storage unit of the computer 17.
- the A scan images A1 to A20 show tomographic images extending over the width D in the X direction of the fundus, and the images composed of the A scan images A1 to A20 are also called B scan images.
- the B scan image B2 at the same location as the B scan image B1 made up of the A scan images A1 to A20 is acquired by the A scan images A21 to A40, and the tomographic images B1 and B2 indicated by the dotted lines of the two frames are obtained from the computer 17. Stored in the storage unit.
- each scan line scans the same part of the fundus in the X direction, each scan line should be illustrated as an overlapping line, but is illustrated as being shifted in the vertical direction for explanation.
- the fundus region 100a is scanned scanning interval P 1/2 narrow scan interval than H, that is, in a half of the spacing of the scanning interval P H scan interval P L in the X direction.
- the fundus position of the scan line at each sampling time ti is a predetermined scan interval P H (twice the narrow scan interval P L in FIG. 2) in the horizontal direction.
- P H twice the narrow scan interval P L in FIG. 2
- the fundus is scanned in high density in the X direction finely by half.
- scanning in a narrow interval of high density becomes a B-scan of the low-speed (S L) to be performed at half the rate for a given scan speed S H, the scanning at a predetermined scanning interval slow scan
- the B-scan is twice as fast ( SH ).
- the scan line of the low speed S L for example in the sampling instant t8, sampling the fundus position the scan line of the speed S H is scanned at a sampling time point t4, A scanned image A8 at that time is acquired, the sampling time point t9 in double-speed S scan line H samples the fundus position scanned at an intermediate time point of the sampling time points t4 and t5, a scanned image A9 at that time is acquired, the sampling time point t10, the scan line of the speed S H Samples the fundus position scanned at the sampling time t5, and an A-scan image A10 at that time is acquired.
- scanned images A11 ⁇ A20 are acquired. Since the low-speed S L scan line scans only half of the width D to be scanned even at the sampling time t20, the remaining half is sampled at the sampling time t21 to t40, as shown in FIG.
- a B-scan image B3 composed of A-scan images A1 to A40 as shown in c) is acquired.
- A-scan that constitute the B-scan images obtained by scanning the X-direction width D is an imaging target in a scan interval P L is a scan interval of 1/2 of the width than the predetermined scan interval P H the number of images (40) is larger than the number of a-scan images constituting the B-scan images obtained by scanning the same X-direction width D at a predetermined scan interval P H (20 pieces).
- capturing the same part at a scan interval of 1/2 means capturing at a scan rate of 1/2, and the scan interval at a predetermined interval, that is, each sampling time point and each sampling of the double-speed scan line.
- the fundus position at the intermediate point in time is sampled, and the fundus is scanned finely and densely with twice the number of samplings, so that a high-definition tomographic image can be obtained.
- the B scan image B3 obtained in this way is an image extending in the X direction.
- the number of pixels in the entire width of the B scan image B3 in the range corresponding to D on the retina is twice the number of pixels of the B scan images B1 and B2.
- the high-density scanning interval P L B-scan image B3 obtained in is compressed in the X direction as shown in the FIG. 2 (e), the new B-scan image B4 is generated.
- the n A scan images are compressed in the scan direction every n.
- the compressed A-scan images are combined in the scanning direction to generate a new tomographic image.
- the A scan images A1 to A1 constituting the B scan image B3 are doubled. Every two A40s are compressed in the X direction.
- each pixel of the A scan images A1 and A2 is added and averaged in the X direction to create a new A scan image A1 ′.
- Images A3 and A4, A scan images A5 and A6,... A scan images A39 and A40 are added and averaged to obtain new A scan images A2 ′, A3 ′,. create.
- the A scan images A1 ′ to A20 ′ created in this way are combined in the X direction so that the image shown in FIG. 2E becomes a new B corresponding to each of the B scan images B1 and B2.
- a scanned image B4 is generated.
- two A-scan images are added and averaged in the scanning direction to create one new A-scan image.
- a new A-scan image is obtained by filtering the two A-scan images.
- One A-scan image may be created.
- filter processing include moving average processing and median processing.
- a compression process such as adding after performing a filter process on the two A-scan images may be performed.
- the width of this as in the horizontal direction to compress the X direction of B-scan images B4 picture is the same as the width of the resulting B-scan images B1, B2 of the image scan of a predetermined interval width P H .
- the B-scan image B4 is obtained by averaging the high-density B-scan image B3 in the horizontal direction, and each pixel records a fine portion of the fundus. Therefore, since the addition average of each pixel is also the addition average value of the fine portion, the B-scan image B4 is an image (fine image) excellent in reproducibility of the finer portions than the B-scan images B1 and B2. It has become.
- the B-scan image B4 obtained as described above is a finer image than the B-scan images B1 and B2, and the speckle pattern is emphasized to stand out. Therefore, the speckle pattern is actively used. Thus, it is extremely effective when trying to obtain more detailed information about the state of the fundus tissue from the tomographic image.
- the speckle pattern is an image pattern based on a phenomenon in which a portion having a high scattered light intensity and a portion having a low scattered light intensity are generated by countless superposition of scattered light from a scatterer in a measurement target.
- the speckle pattern itself does not directly reflect the structure of the fundus oculi to be measured, the speckle pattern is simply regarded as noise because it changes depending on the state of the fundus. Rather, it is being researched to actively utilize its statistical properties.
- the time interval between the samplings to be added is extremely short and the scanning speed is slow, so the spatial movement distance during the sampling time is also short, and the speckle pattern hardly changes during sampling, and high-contrast speckles The signal can be observed.
- the scanning speed is fast, so the spatial distance that moves during the sampling time is long, the speckle pattern changes during that time, and the average value is sampled, so the speckle contrast is low.
- the speckle contrast is further lowered in the image after the averaging process.
- the image for interpretation is created by averaging the B scan image B1 and the B scan image B2 shown in FIG. 2, assuming that there is no positional deviation, the A1 of the B scan image B1 and the B scan image B2 A21 of B scan image B1, A2 of B scan image B2, A22 of B scan image B2,... A20 of B scan image B1 and A40 of B scan image B2 are averaged.
- the interval between the sampling time t1 of A1 of the B-scan image B1 and the sampling time t21 of A21 of the B-scan image B2 is one scan. If the speckle pattern changes due to microscopic fixation during one scan, the speckle pattern disappears in the same way as other noises when A1 and A21 are added and averaged, leaving only the tomographic structure. . The longer the sampling time interval (difference in image acquisition time) of the A-scan images to be averaged, the higher the possibility that the speckle pattern will change due to fine fixation movement.
- the entire width of the B scan image B3 whose measurement width is twice the measurement width of the B scan images B1 and B2 is substantially the same as the entire width of the B scan images B1 and B2.
- the two adjacent A-scan images are added and averaged to create a new A-scan image, which is combined to obtain a new B-scan image B4.
- the two A-scan images A1 and A-scan images A2, the A-scan image A3 and the A-scan image A4,... Are sampled continuously, and the sampling time interval between the two A-scan images (Difference in the time to obtain the image) is very short.
- the predetermined scan interval P H sampled 1000 times in one scan, B-scan images B1 consisting of 1000 A scanned image of, respectively, as shown in FIG. 3 (b)
- scanning in a narrow interval of high density becomes a scan low speed S L that is performed at a speed of apparent 1/10 for a given scan, fast S H of the predetermined scanning 10 times to slow scan Scan.
- the scan lines of slow scan speed S L is the scanning speed S H of the scan line sampling time point t (i)
- the fundus portions located at respective distances obtained by dividing the scanning distance between the sampling time points t (i + 1) by 10 are represented by sampling time points t (10i + 1), t (10i + 2),... T (10i + 9), t ( Sampling is performed at 10 sampling points 10i + 10).
- This narrow scan interval P L B-scan image 11 acquired in is compressed in the X direction as shown in FIG. 3 (e), the new B-scan image B12 is generated.
- every 10 A scan images are compressed in the X direction. To do. Specifically, for every 10 adjacent A-scan images A1 to A10, A11 to A20, A21 to A30,..., A9991 to A10000, as shown in FIG. Each pixel is averaged in the X direction to create 1000 new A-scan images A1 ′, A2 ′,... A1000 ′, and these 1000 A-scan images are combined in the X direction to create an image.
- a new B-scan image 12 corresponding to the overall width of each of the B-scan images B1 to B10 is generated.
- a case where the image to be read to generate the B-scan image B11 new B-scan image B12 is compressed in the scanning direction obtained by the high-density scanning a narrow scan interval P L conventional If a B-scan image B1, B2, the one by averaging the ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ B10 read images of a plurality of obtained by scanning at a predetermined scanning interval P H (10 sheets) as Is generally as shown in FIG.
- the number of A-scans is 1000 for one B-scan image, and the total of 10 is 10,000.
- the number of B-scan images obtained by high-density scanning as in this embodiment is 10000 when compressed in the scanning direction.
- the present embodiment In order to generate a B-scan image per sheet, the present embodiment generally requires 10 times the time of the conventional technique, but in order to acquire 10 B-scan images in the conventional technique, The whole is not changed. Further, the number of times of addition for obtaining the A scan image constituting the image for interpretation is not changed by 10 times.
- the sampling time interval of the A-scan images to be added (difference in the time at which the images were obtained) is free for one scan.
- the B-scan image obtained by the high-density scan is compressed in the scanning direction as in the present embodiment, 10 A-scan images sampled continuously are added.
- the longer the sampled time interval between images (the greater the difference in the time at which the images were acquired), the greater the change in speckle pattern. Therefore, in the prior art, the speckle pattern is reduced by the averaging process, In the present embodiment, the speckle pattern is emphasized by the averaging process.
- the time required for one scan is longer than that of the conventional method, and thus a method for dealing with the problem of fixation eye movement during the period is required.
- the effect of fixation micromotion appears as a positional shift of each image when 10 B-scan images are added and averaged.
- the effect of fixation micromotion is present. Appears as distortion in the B-scan image. If an image with such distortion is used as it is, there is a problem in interpretation, and it is desired to correct the distortion appropriately.
- the correction methods there is also a method of correcting following the ideal tomographic image reference model estimated by the diopter information of the eye to be examined.
- an image (hereinafter referred to as a reference image) that is less likely to cause distortion by performing high-speed scanning at the same place as the high-density scan before and / or after the high-density scan is performed once or a few times.
- Image is acquired, and a method of correcting distortion of a tomographic image obtained by high-density scanning using the reference image is adopted.
- the scan interval of this alignment scan may be the first scan interval described above, but since it is desired to obtain a tomographic image in a short time, the tomographic image is scanned at a scan interval wider than the first scan interval.
- a scan interval such as a so-called draft scan may be acquired. Note that the scan interval during the high-density scan is performed at the second scan interval as described above.
- the reference image for alignment is required to have a more accurate structural feature of the scanned part, but as described above, even if the same part is scanned, the tomographic image obtained by the fixation state
- the structure may exhibit different forms for each scan. Therefore, in the present embodiment, the high-density image is used so that the possibility that the reference image for alignment is almost the same as the high-density tomographic image (scanning the same place on the eye to be examined) is the highest.
- a reference image is created from the tomographic image obtained by the alignment scan immediately before the scan. In this case, the alignment scan may be performed only once and one of them may be used as a reference image, or the last one of the tomographic image groups obtained after performing the alignment scan multiple times may be used as a reference image.
- Other methods for determining the reference image include selecting one image having the highest correlation among a plurality of tomographic image groups, setting a simple average image of the plurality of tomographic image groups, and aligning average images of the plurality of tomographic image groups.
- Various variations can be considered, such as being an averaged alignment image based on one sheet having the highest correlation among a plurality of tomographic image groups.
- Various methods can be adopted as this alignment method. As a first example, it is conceivable to perform the operation based on the same one or more boundary segmentation lines among the segmentation lines. As a second example, it is conceivable to carry out based on the intensity pattern of the tomographic image based on the blood vessel structure. In this case, magnification correction in the scanning direction (lateral direction) and correction of uneven scanning speed can be performed. Furthermore, as a third example, it can be considered to carry out based on the correlation of the same one or more images.
- the alignment scan can be omitted if the same part of the same eye to be inspected in advance, such as during reexamination. In this case, the reproducibility of the same part needs to be ensured by a follow-up function or the like, but a tomographic image of the same part taken separately in advance can be used as a reference image.
- a follow-up function or the like
- the tomographic imaging apparatus As described above, according to the tomographic imaging apparatus according to the present embodiment, it is possible to obtain a very high-quality image for interpretation.
- a tomographic image having the same measurement width as the tomographic image obtained by compressing in the scanning direction and scanning at a predetermined scanning speed a plurality of tomographic images obtained by scanning at a predetermined scanning speed Speckle patterns that are regarded as noise and disappeared when obtaining an image for image interpretation by averaging the images are emphasized and become conspicuous in the new tomographic image obtained.
- Speckle patterns that are regarded as noise and disappeared when obtaining an image for image interpretation by averaging the images are emphasized and become conspicuous in the new tomographic image obtained.
- tomographic image distortion that occurs due to the effect of fixation micromotion during image acquisition in high-density scanning, use a tomographic
- the B-scan image obtained by the high-density scan is compressed to 1 / n in the scan direction, but is a multiple of the scan interval.
- n may be different from a multiple n at the time of compression.
- a B scan image obtained by scanning at an interval of 1/10 is not added and averaged for every 10 adjacent A scan images, but is added and averaged every 8 to 9 images to obtain a new compressed image.
- a B-scan image may be generated.
- the width on the retina corresponding to one pixel in the scanning direction of the compressed B scan image and the measurement width of the B scan image obtained by scanning at a predetermined interval are different.
- the multiple n of the scan interval is different from the multiple n at the time of compression. You may do it.
- the same A-scan image may be used for the calculation. The conceptual diagram of these embodiment is shown in FIG.5 and FIG.6.
- the example on the left side of FIG. 5 is a case where the multiple n of the scan interval described so far and the multiple n at the time of compression are the same, but the example on the right side is 1 more than the sampling number L when scanning at a predetermined interval. This is the case when there is a lot of sampling.
- a new B-scan image compressed is generated by adding and averaging the scan image and the j + 2nd A-scan image.
- the last A scan image in the scanning direction is overlapped and averaged using the next set of three A scan images.
- E Eye to be examined 10 Demultiplexing / combining optical system 11 Low coherence light source 12 Light quantity adjusting mechanism 13 Optical coupler 14 Collimating lens 16 Spectrometer 17 Computer 18 Tomographic image generating means 19 Image processing means 20 Beam splitter 30 Measuring optical system 31 Focus lens 34 x-axis scanning mirror 35 y-axis scanning mirror 36 scan lens 37 dichroic mirror 38 objective lens 40 reference optical system 42 objective lens dispersion compensation glass 46 dichroic mirror 47 condenser lens 48 variable aperture 49 reference mirror 50 eye dispersion compensation glass to be examined
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Abstract
Description
10 分波/合波光学系
11 低コヒーレンス光源
12 光量調整機構
13 光カプラ
14 コリメートレンズ
16 分光器
17 コンピュータ
18 断層画像生成手段
19 画像処理手段
20 ビームスプリッタ
30 測定光学系
31 フォーカスレンズ
34 x軸走査ミラー
35 y軸走査ミラー
36 スキャンレンズ
37 ダイクロイックミラー
38 対物レンズ
40 参照光学系
42 対物レンズ用分散補償ガラス
46 ダイクロイックミラー
47 集光レンズ
48 可変アパーチャ
49 参照ミラー
50 被検眼分散補償ガラス
Claims (6)
- 被検眼眼底上に測定光を走査させて該被検眼眼底の断層像を撮影する断層像撮影手段と、
前記撮影された断層像の画像を走査方向に圧縮して新たな断層画像を生成する画像処理手段と、を備えることを特徴とする断層像撮影装置。 - 前記断層像撮影手段が、第一のスキャン間隔よりも狭い第二のスキャン間隔で走査して被検眼眼底の断層像を撮影し、
前記画像処理手段が、前記第二のスキャン間隔で撮影された断層像の画像を走査方向に圧縮して新たな断層画像を生成し、
前記新たな断層画像の走査方向の測定幅が、前記第一のスキャン間隔で走査して得られる断層画像の走査方向の測定幅に相当する画像の幅であることを特徴とする断層像撮影装置。 - 前記画像処理手段が、前記第二のスキャン間隔で撮影された断層像の画像を構成するAスキャン画像をn個毎に走査方向に圧縮し、圧縮されたAスキャン画像のそれぞれを走査方向に結合して前記新たな断層画像を生成することを特徴とする、請求項2に記載の断層像撮影装置。
- 前記圧縮されたAスキャン画像のそれぞれが、n個のAスキャン画像を走査方向に加算平均処理することによって生成されることを特徴とする、請求項3に記載の断層像撮影装置。
- 前記圧縮されたAスキャン画像のそれぞれが、n個のAスキャン画像をフィルタ処理することによって生成されることを特徴とする、請求項3に記載の断層像撮影装置。
- 前記第二のスキャン間隔が、前記第一のスキャン間隔の1/nであることを特徴とする、請求項2~5のいずれか1項に記載の断層像撮影装置。
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CN201680011473.9A CN107249432A (zh) | 2015-02-27 | 2016-02-26 | 断层像拍摄装置 |
KR1020177023244A KR20170122192A (ko) | 2015-02-27 | 2016-02-26 | 단층상 촬영 장치 |
JP2017502499A JP6599973B2 (ja) | 2015-02-27 | 2016-02-26 | 断層像撮影装置 |
US15/553,681 US10188286B2 (en) | 2015-02-27 | 2016-02-26 | Tomographic image capturing device |
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TWI749531B (zh) * | 2020-04-22 | 2021-12-11 | 晉弘科技股份有限公司 | 掃描裝置以及光學同調斷層掃描系統 |
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