JP5637720B2 - Tomographic imaging method and tomographic imaging apparatus control device - Google Patents

Tomographic imaging method and tomographic imaging apparatus control device Download PDF

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JP5637720B2
JP5637720B2 JP2010082809A JP2010082809A JP5637720B2 JP 5637720 B2 JP5637720 B2 JP 5637720B2 JP 2010082809 A JP2010082809 A JP 2010082809A JP 2010082809 A JP2010082809 A JP 2010082809A JP 5637720 B2 JP5637720 B2 JP 5637720B2
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JP2011214966A (en
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信人 末平
信人 末平
坂川 幸雄
幸雄 坂川
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キヤノン株式会社
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Description

  The present invention relates to a tomographic imaging apparatus and a tomographic imaging apparatus control apparatus.

  Currently, various types of ophthalmic equipment using optical equipment are used. For example, as an optical device for observing eyes, there are an anterior ocular segment photographing machine, a fundus camera, a confocal laser scanning ophthalmoscope, and the like. Among these, an optical tomography apparatus based on optical coherence tomography (OCT) using low-coherence light is an apparatus that can obtain a tomographic image of an inspection object with high resolution. Therefore, it is becoming an indispensable device for specialized retina outpatients as an ophthalmic device. Hereinafter, this apparatus will be described as an OCT apparatus.

  The OCT apparatus divides low-coherent light into reference light and measurement light, irradiates the inspection object with the measurement light, and causes the return light from the inspection object and the reference light to interfere with each other. Can be measured. That is, a two-dimensional or three-dimensional tomographic image can be obtained by scanning the measurement light on the inspection object. However, when the object to be inspected is a living body such as an eye, image distortion due to eye movement becomes a problem. Therefore, it is required to measure at high speed and with high sensitivity.

  As one of the methods for measuring at high speed and with high sensitivity, a method of simultaneously measuring a plurality of points on an inspection object is disclosed in Patent Document 1. According to this, a plurality of light sources are created by dividing light from one light source by slits. These lights are divided into a plurality of measurement lights and reference lights by a beam splitter. The measurement light is irradiated onto the inspection object, and the return light from the inspection object and the reference light are combined by the beam splitter. Then, the plurality of combined lights are incident on the grating and are simultaneously detected by the two-dimensional sensor. As described above, Patent Document 1 enables speeding up by simultaneous measurement using a plurality of measurement lights.

Special table 2008-508068

  However, when creating a two-dimensional intensity image (a cross-sectional image perpendicular to the measurement light) from the three-dimensional data of an OCT apparatus that measures a plurality of points simultaneously using a plurality of measurement lights, the inside of the cross-sectional image depends on the device configuration. It becomes a two-dimensional intensity image in which the difference in each region is conspicuous.

  For example, when one cross-sectional image is created from tomographic images obtained by simultaneously measuring a plurality of points, the connection portion becomes an image that stands out depending on the configuration of the optical system. In other words, it is not a problem if the optical systems for each of the multiple points are completely equivalent. Otherwise, the contrast and resolution differ depending on the depth direction of the tomographic image. Things happen.

  The present invention has been made to solve the above-described problem, and in a tomographic imaging apparatus that acquires cross-sectional images from signals of a plurality of combined lights obtained using a plurality of measurement lights, an optical system in the tomographic imaging apparatus It is intended to make the difference in the cross-sectional image caused by the inconspicuous.

The tomographic imaging apparatus of the present invention synthesizes a plurality of return lights and reference light obtained by irradiating a test object with a plurality of measurement lights, and from the plurality of synthesized lights obtained by the synthesis, A tomographic imaging apparatus that acquires a cross-sectional image of an object, wherein the plurality of combined lights are detected via an optical system and a signal of the plurality of combined lights is acquired between the signals of the plurality of combined lights a difference, the correcting means for generating a signal obtained by correcting the difference in the depth direction of the inspection object by the configuration of the said optical system sensor, the corrected signal or al of the plurality of combined lights And generating means for generating a cross-sectional image perpendicular to the measurement light of the inspection object.

  According to the present invention, in a tomographic imaging apparatus that acquires a cross-sectional image from a plurality of combined light signals obtained using a plurality of measurement lights, differences in the cross-sectional image caused by the optical system in the tomographic imaging apparatus are hardly noticeable. I can do it.

It is a figure explaining embodiment of this invention. It is a figure explaining the apparatus structure in 1st embodiment. It is a figure explaining the spectrometer in 1st embodiment. (A) Two-dimensional intensity image of model eye in first embodiment, (b) Tomographic image straddling region. It is a figure explaining the signal processing process in 1st embodiment. It is a figure explaining the three-dimensional arrangement | positioning of the tomogram in 2nd embodiment. It is a figure which shows the (a) signal processing process in 3rd embodiment, and the (b) wavelength filter. It is a figure which shows the case where there is no (a) filter of the two-dimensional intensity image in 3rd embodiment, (b) When using a depth filter, (c) When using an optical filter.

  The optical coherence tomography apparatus according to the present embodiment irradiates a test object with a plurality of measurement lights via a measurement optical path, and the return light is guided to a detection position via the measurement optical path. The measuring light can scan the inspection object with a scanner. The reference light is guided to the detection position via the reference light path. The return light and the reference light guided to the detection position are detected as combined light by the sensor. A mirror is arranged in the reference optical path, and the position of the coherence gate can be adjusted by the stage. The processing in each of the following configurations may be performed by reading a computer program stored in a recording medium when the computer functions as an alternative device.

(First embodiment)
Hereinafter, the first embodiment will be described in detail with reference to the drawings. The present embodiment is an OCT apparatus that uses a plurality of measurement lights, and makes a connection portion of an image less noticeable due to a difference in characteristics generated by the configuration of a spectrometer.

  FIG. 2 is a diagram illustrating a configuration of the optical tomographic image apparatus according to the present embodiment. As shown in FIG. 2, the OCT apparatus 200 forms a Michelson interference system as a whole.

(Optical system)
Outgoing light 204, which is light emitted from the light source 201, is guided to the single mode fiber 210 and enters the optical coupler 256, and the optical coupler 256 uses the three optical paths of the first optical path, the second optical path, and the third optical path. Is divided into outgoing lights 204-1 through 204-1. Further, each of the three outgoing lights 204-1 to 204-3 passes through the polarization controller 253-1, and the optical couplers 231-1 to 231-3 reference light 205-1 to measurement light 206-1 to 206-1. It is divided into. The three measurement beams 206-1 to 206-3 divided in this way are returned as return beams 208-1 to 208-3 reflected or scattered by the respective measurement locations of the retina 227 in the eye 207 to be observed. . Then, the optical couplers 231-1 to 231-3 combine with the reference beams 205-1 to 205-1 that have passed through the reference beam path to become combined beams 242-1 to 242-3. The combined lights 242-1 to 242-3 are spectrally separated for each wavelength by the transmission diffraction grating 241 and are incident on the line sensor 239. The line sensor 239 converts the light intensity of each wavelength into a voltage for each sensor element, and the computer 225 generates a tomographic image of the eye 207 to be examined based on the value.

  Here, the light source 201 will be described. The light source 201 is an SLD (Super Luminescent Diode) which is a typical low-coherent light source. In consideration of measuring the eye, near-infrared light is suitable for the wavelength. Furthermore, since the wavelength affects the resolution in the lateral direction of the obtained tomographic image, it is desirable that the wavelength be as short as possible. Here, the center wavelength is 840 nm and the wavelength width is 50 nm. Other wavelengths may be selected depending on the measurement site to be observed. As the type of light source, SLD is selected here, but it is only necessary to emit low-coherent light, and ASE (Amplified Spontaneous Emission) can also be used.

  Next, the reference light path of the reference light 205 will be described. Each of the three reference lights 205-1 to 205-1 to 203-1, which is divided by the optical couplers 231-1 to 231-1, passes through the polarization controller 253-2 and is emitted as substantially parallel light by the lens 235-1. Next, the reference beams 205-1 to 205-2 pass through the dispersion compensation glass 215, and are collected on the mirror 214 by the lens 235-2. Then, the directions of the reference beams 205-1 to 205-1 to 3 are changed by the mirror 214 and travel again toward the optical couplers 231-1 to 231-1. The reference beams 205-1 to 203-1 are passed through the optical couplers 231-1 to 231-1 and guided to the line sensor 239. The dispersion compensating glass 215 compensates the reference light 205 for dispersion when the measurement light 206 reciprocates through the eye 207 and the scanning optical system. A typical value is assumed to be 23 mm for the average Japanese eyeball diameter. Furthermore, 217-1 is an electric stage, which can move in the direction shown by the arrow, and can adjust the optical path length of the reference beam 205. The electric stage 217-1 is controlled by the computer 225. In the present embodiment, the mirror 214, the electric stage 217-1, and the dispersion compensation glass 215 are the same in the three optical paths, but may have different configurations.

  Next, the measurement optical path of the measurement light 206 will be described. Each of the measurement lights 206-1 to 206-3 divided by the optical couplers 231-1 to 231-3 passes through the polarization controller 253-4, and is emitted as substantially parallel light by the lens 220-3. Is incident on the mirror of the XY scanner 219 constituting the. Here, for the sake of simplicity, the XY scanner 219 is described as a single mirror, but in reality, two mirrors, an X scan mirror and a Y scan mirror, are arranged close to each other, and an optical axis is placed on the retina 227. Raster scan in a direction perpendicular to Further, the lenses 220-1, 3 and the like are adjusted so that the respective centers of the measuring beams 206-1 to 206-3 are substantially coincident with the rotation center of the mirror of the XY scanner 219. The lenses 220-1 and 220-2 are optical systems for the measurement light 206-1 to 206-3 to scan the retina 227, and have a role of scanning the retina 227 with the measurement light 206 near the cornea 226 as a fulcrum. The measuring beams 206-1 to 206-3 are each configured to form an image at an arbitrary position on the retina.

  Reference numeral 217-2 denotes an electric stage which can be moved in the direction indicated by the arrow, and the position of the associated lens 220-2 can be adjusted. By adjusting the position of the lens 220-2, each of the measurement lights 206-1 to 206-3 can be condensed and observed on a desired layer of the retina 227 of the eye 207 to be examined. When the measurement light 206-1 to 206-1 is incident on the eye 207 to be examined, the return light 208-1 to 208-3 is reflected or scattered from the retina 227, passes through the optical couplers 231-1 to 231-3, and is guided to the line sensor 239. It is burned. The electric stage 217-2 is controlled by the computer 225. By adopting the above configuration, three measurement beams can be scanned simultaneously.

  Next, the configuration of the detection system will be described. The return lights 208-1 to 208-3 reflected and scattered by the retina 227 and the reference lights 205-1 to 205-1 are combined by the optical couplers 231-1 to 231-3. Then, the synthesized light beams 242-1 to 242-3 are incident on the spectroscope to obtain a spectrum. The computer 225 performs signal processing on these spectra.

(Spectrometer)
Here, the spectroscope will be specifically described. In this configuration, since a plurality of combined lights are processed by one line sensor, the cost can be reduced and the control can be simplified as compared with the two-dimensional sensor.

  FIG. 3 shows a configuration when three synthesized lights (242-1 to 3) are incident on the spectroscope in order to explain in detail the part of the spectroscope shown in FIG. 2. The fiber ends 260-1 to 260-3 are arranged away from each other, and the combined lights 242-1 to 242-3 are incident on the spectroscope from the fiber ends 260-1 to 260-3, respectively. At this time, the directions of the fiber ends 260-1 to 260-1 are adjusted in advance so that the combined beams 242-1 to 242-3 are perpendicularly incident on the main surface of the lens 235, that is, telecentric. With the lens 235, the three combined lights 242-1 to 242-3 become substantially parallel lights, and the three combined lights 242-1 to 242-3 are all incident on the transmissive diffraction grating 241. In order to reduce the loss of the amount of light, the transmissive diffraction grating 241 is disposed near the pupil of the optical system, and it is necessary to provide a stop on the surface of the transmissive diffraction grating 241. In addition, since the transmissive diffraction grating 241 is disposed to be inclined with respect to the main surface of the lens 235, each light beam of the combined lights 242-1 to 242-3 on the surface of the transmissive diffraction grating 241 has an elliptical shape. Therefore, the diaphragm provided on the surface of the transmissive diffraction grating 241 needs to be elliptical. The combined lights 242-1 to 242-3 diffracted by the transmissive diffraction grating 241 are incident on the lens 243, respectively. Here, the diffracted synthesized lights 242-1 to 242-3 in FIG. 3 show light beams having only the center wavelength, and the diffracted synthesized lights of other wavelengths are shown only as principal rays for simplicity. Each of the diffracted combined lights 242-1 to 242-3 incident on the lens 243 is imaged on the line sensor 239, and a spectrum is observed in the range indicated by the arrows 261-1 to 261-3. Table 1 shows the relationship between each synthesized light, diffraction grating, and line sensor (distribution characteristics of each synthesized light on the line sensor) for the upper and lower limits of the wavelength of the measurement light used in this embodiment and the center wavelength of 840 nm. Is a summary. It can be seen that the diffraction angle varies depending on the incident angle to the transmission diffraction grating 241, and as a result, the imaging position varies depending on the combined light. Further, the number of pixels when detecting with a sensor element of 12 μm per pixel varies depending on each combined light.

(Signal processing)
The signal processing process in Example 1 is demonstrated using FIG.

  In step A1, measurement is started. In this state, the OCT apparatus 200 is activated, and an eye to be examined which will be described later is arranged at the measurement position. Further, the adjustment necessary for the measurement is performed by the operator, and the measurement is started.

  In step A2, a plurality of combined light signals are acquired. Here, a signal obtained by scanning the three measuring beams 206-1 to 206-3 with the XY scanner 219 is detected by the line sensor 239, and the detected data is acquired by the computer 225 functioning as a first acquisition unit. To do. In the coordinate system shown in FIG. 2, for example, 512 lines are scanned in the x direction and 200 lines are scanned in the y direction. However, the y direction is adjusted to be 500 lines with three measurement lights except for the overlapping portion. The line sensor 139 receives the combined light 242-1 to 242-3 by the three measurement lights, and acquires one-dimensional array of A-Scan data (4096 pixels). Then, 512 continuous lines in the x direction are stored in units of two-dimensional B-Scan data (4096 × 512 pixels, 12 bits). When scanning is completed, 200 pieces of this data are stored per measurement.

  An image of the model eye thus measured is shown in FIG. The image shown in FIG. 4 is an image taken in a state where the position of the coherence gate that corrects the mechanical difference in the fiber length is not adjusted. The model eye is a glass sphere having optical characteristics, size, and capacity similar to those of a living eye. Concentric circles and radial patterns are arranged on the fundus of the model eye. The coherence gate is a position in the measurement optical path where the optical distance coincides with the reference optical path, and the position of the coherence gate can be adjusted by moving the position of the mirror 214.

  4A is a two-dimensional intensity image, and FIG. 4B is a tomographic image of the first line across three measurement regions. There are a first region 401, a second region 402, and a third region 403 having a width indicated by a white arrow for each of the three measurement beams. Then, there are overlapping portions 404 and 405 surrounded by dotted lines at their boundaries.

In step A3, signal processing corresponding to the characteristics in the OCT apparatus 200 (in the tomographic imaging apparatus) is performed. As described above, the characteristics of the OCT apparatus 200 affect the distribution characteristics of the combined light on the line sensor 139. Therefore, the computer 225 also functions as a second acquisition unit that acquires the distribution characteristics of the combined light. Here, a two-dimensional intensity image (a cross-sectional image perpendicular to the irradiation direction of the measurement light) will be described. In the case of the OCT apparatus, the intensity I det of light detected by the spectroscope is expressed as follows using the electric fields of reference light and return light, Er, Es, and wave number k, respectively.

Autocorrelation component of the first term of the right side is the reference light I r, the second term is called the interference component I rs in the cross-correlation of the reference light and return light, the third term is the return light of the autocorrelation component I s. Since the SLO device detects the return light, the integration with respect to the wave number of the third term corresponds to the SLO image. On the other hand, the OCT apparatus generates a tomographic image from the interference component of the second term. Further, since the third term is smaller than the first and second terms, it is difficult to detect with the OCT apparatus using the line sensor. However, a two-dimensional intensity image corresponding to the SLO image is created by integrating the interference component of the second term. This signal processing will be described in detail with reference to FIG.

  In step S1-1, the waveform of each synthesized light is cut out and shaped. First, a zero element is added to each A-Scan data to make 2 n data as a whole, for example, 2048. By doing so, the pixel resolution when the tomographic image is obtained can be improved.

  In step S1-2, noise is removed. Noise removal removes the fixed pattern included in the reference light component and the interference component. Here, subtraction may be performed with the reference light component acquired in advance, or an average value of each wavelength of the B-Scan data may be used. As a result, the component of the second term of Formula 1 can be extracted.

  In step S1-3, a tomographic image is generated. First, since the A-Scan data of each measurement light is data that is equally spaced with respect to the wavelength, wavelength wave number conversion is performed to obtain data that is equally spaced with respect to the wave number. Next, this data can be subjected to discrete Fourier transform to obtain intensity data with respect to depth.

  However, in this spectrometer, since the regions of the detection light that are imaged on the line sensors are different, the numerical resolution in the depth direction and the attenuation characteristics in the depth direction (Roll-OFF) per pixel are different. Therefore, resampling is performed in the z direction to make the resolution in the depth direction uniform. Here, the reference distance per pixel is the resolution of the second measurement light (measurement light having a central measurement area). Further, correction is performed to match the attenuation characteristics in the depth direction. Here, the attenuation characteristics of all measurement lights are measured or simulated in advance, and correction is performed by converting them to the intensity of the central measurement light. Naturally, not only the difference in characteristics due to the spectroscope, but also the dispersion due to the measurement path, etc. are corrected as appropriate.

  In step S1-4, a depth filter is applied. That is, since resampling is performed in the z direction, the lengths of the B-Scan image arrays of the respective measurement lights are different. This is cut out to the same length by a depth filter. In this way, a tomographic image can be obtained. Further, in each measurement region, adjustment is made so that the dynamic range of the image due to different noise and transmittance is the same. That is, the entire image of each measurement region is adjusted so that the B-Scan tomographic images at the same position measured with different measurement lights in the boundary regions 404 and 405 are the same. The tomogram obtained in this way has the same depth resolution and attenuation characteristics in the depth direction regardless of the measurement light.

  In step A4, a two-dimensional intensity image of each region is obtained. Here, the signal of the B-Scan tomographic image obtained in step S3 is integrated for each line, thereby obtaining a two-dimensional intensity image of each region 200 × 512.

  In step A5, an entire two-dimensional intensity image acquired with the three measuring beams is obtained. Here, the overlapping area is eliminated, the positions of the images in the XY directions are aligned, and the contrast is adjusted as necessary to obtain an entire two-dimensional intensity image.

  Thus, the eye to be examined is measured using the OCT apparatus in which the signal processing according to the apparatus characteristics is performed.

  Even in the case of different measurement lights as described above, by making the tomographic images at the same position in the boundary region the same, the difference between the images mainly due to the characteristics of the spectroscope is reduced, and the two-dimensional inconspicuous connection portion. An intensity image can be obtained.

  Naturally, data of a three-dimensional tomographic image that has been subjected to signal processing in accordance with the device characteristics is also generated, and an image in which the XZ plane and each XY plane straddling each region are not conspicuous is obtained.

(Second embodiment)
A second embodiment will be described. Here, differences from the first embodiment will be mainly described. In the present embodiment, measurement is performed by changing the position of the coherence gate with each measurement light. That is, in the OCT measurement, due to the attenuation characteristic, the stronger the signal intensity is obtained the closer the coherence gate is to the measurement position of the object to be inspected. Therefore, when measuring a fundus that is curved or tilted, it is desirable to optimally arrange the position of the coherence gate of each measurement light. As a result, when creating a two-dimensional intensity image, the difference between the regions becomes noticeable. In addition, although Example 1 showed the example which used the model eye, in this embodiment, the eye to be examined is actually measured.

  The difference in the apparatus configuration is that the reference mirror on the electric stage 217-1 can be controlled independently for each measurement light. As a result, the position of the coherence gate can be independently adjusted.

  Next, the signal processing process will be described with reference to FIGS. 1 and 5, but differences from the first embodiment will be described.

  In step A2, a plurality of combined lights are acquired. First, the depth position for each measurement region is set. In this setting method, vertical and horizontal tomographic images are acquired in advance at the time of alignment or the like and determined based on the information. Since the alignment is general, the description thereof is omitted. Thereafter, each region is measured. Here, it is assumed that the position of the coherence gate is the same in the first region and the third region, and the position of the coherence gate in the second region is closer to the retina than the others.

In step A3, signal processing according to the device characteristics is performed. Here, a case where the coherence gate is different for each measurement light will be described.
In step S1-1, waveform shaping is performed.
In step S1-2, noise is removed.

  In step S1-3, tomographic image generation is performed. First, wavelength wave number conversion is performed on the A-Scan data of each measurement light, and discrete Fourier transform is performed to obtain intensity data with respect to depth. Here, since the same spectrometer is used for each measurement region, it is assumed that the depth resolution and the attenuation characteristics from the coherence gate are the same. However, since the position of the coherence gate is different, an image is created in accordance with the position of the coherence gate in the image farthest from the coherence gate. Note that the position of the coherence gate may be determined based on the position of the reference mirror.

  Here, FIG. 6 schematically shows the relative positional relationship between the B-Scan tomographic images in each region. The B-Scan image of each measurement light is a first tomographic image 601 indicated by a dotted line, a second tomographic image 602 indicated by a solid line, and a third tomographic image 603 indicated by a broken line. The position of the coherence gate of the first tomographic image and the third tomographic image is farther from the inspection object than the position of the coherence gate of the second tomographic image. As a result, the first additional data 604 and the third additional data are added at deep positions, respectively. On the other hand, the second additional data 605 is added at a shallow position. The added data is, for example, an average noise level or zero. By doing so, the ranges in the depth direction in all regions coincide. Then, the attenuation characteristics in the depth direction are corrected so as to be the same in each region. As a result, the contrast of the same layer is continuous in each layer.

  In step S1-4, a depth filter is performed. However, since the number of pixels in all the regions is adjusted to be the same here, it is not necessary except when a specific layer is extracted.

  In step A4, a two-dimensional intensity image of each region is obtained. Here, the signal of the B-Scan tomographic image obtained in step S3 is integrated for each line, thereby obtaining a two-dimensional intensity image of each region 200 × 512.

  In step A5, an entire two-dimensional intensity image acquired with the three measuring beams is obtained. Here, the overlapping area is eliminated, and the positions of the images in the X and Y directions can be matched to obtain an entire two-dimensional intensity image.

  By doing so, it is possible to reduce the difference in the two-dimensional intensity image depending on the position of the coherence gate and to create a two-dimensional intensity image in which the connected portion is not conspicuous.

  Naturally, data of a three-dimensional tomographic image is also generated, and an image in which the XZ plane straddling each region and each XY plane are inconspicuous is obtained.

(Third embodiment)
A third embodiment will be described. Here, differences from the first embodiment will be mainly described. This is a case where a light source is prepared for each measurement region. That is, depending on the SLD light source, the amount of light may not be sufficient, and the light from one light source may be branched to irradiate a plurality of measurement regions simultaneously. On the other hand, when a plurality of light sources are used, characteristics such as spectrum shape and wavelength band are different even if the light sources are from the same manufacturer. As a result, a difference appears in the two-dimensional intensity image of each region.

  The difference in apparatus configuration is mainly that the light source 201 uses three different light sources, and three independent and equivalent spectrometers are arranged.

  Next, the difference in the signal processing process will be described. FIG. 7A shows the signal processing step A3 in FIG. Here, processing when the wavelength spectrum and the band are different will be described.

  In step S3-1, a wavelength filter is applied to the signal from step A2. FIG. 7B shows the wavelength spectrum. Adjustment is performed so as to cut out the same wavelength band for each measurement light. The extraction of the same band is determined by putting each measurement light into each spectrometer and comparing the data. Here, the cutout position of the spectroscope is set so as to match the light source in the second region.

  In step S3-2, waveform shaping is performed. When the shape of each light source spectrum is different, correction is performed so that each reference light becomes the same as the spectrum of the central measurement light. Of course, the present invention is not limited to this, and standardization in which each measurement light is divided by each reference light may be used.

  In step S3-3, noise is removed. This extracts the component of the interference light in Equation 1.

  In step A4, a two-dimensional intensity image of each region is obtained. Here, the spectrum of the interference light obtained in step S3-2 is square-averaged at each pixel and then integrated for each line. As a result, a two-dimensional intensity image of each region 200 × 512 is obtained.

  In step A5, an entire two-dimensional intensity image acquired with the three measuring beams is obtained. Here, the overlapping area is excluded and the positions of the images in the XY directions are matched. Further, in each measurement region, adjustment is made so that the dynamic range of the image due to different noise and transmittance is the same, and an entire two-dimensional intensity image is obtained.

  As described above, even with measurement light from different light sources, it is possible to reduce the difference between the measurement regions and obtain a two-dimensional intensity image in which the connection portion is not conspicuous.

  Here, FIG. 8 shows a two-dimensional intensity image of the fundus imaged with a single measurement light due to a difference in processing. (A) when no filter is used, (b) when a depth filter is used, and (c) when a wavelength filter is used. The layer structure of a specific region can be extracted by actively narrowing the range of the depth filter. A specific wavelength can be emphasized by the wavelength filter. For example, by selecting a wavelength that reacts with a contrast agent or a marker, the position can be recognized. In this way, more information can be obtained by using a two-dimensional intensity image corresponding to a specific depth region, a two-dimensional intensity image corresponding to a specific wavelength, and a tomographic image. Of course, when displaying on the screen, all may be displayed or switched.

  As described above, according to the present embodiment, it is possible to generate a two-dimensional intensity image in which the connection portion is not conspicuous even when the light sources corresponding to each measurement light are individually used.

  When imaging is performed using a contrast agent, a marker, or the like, an image that can confirm the state of the position of a target region or the like of the contrast agent can be obtained by selecting a wavelength according to these.

Claims (7)

  1. A tomography that combines a plurality of return lights and reference light obtained by irradiating the inspection object with a plurality of measurement lights, and acquires a cross-sectional image of the inspection object from the plurality of combined lights obtained by the combination An imaging device,
    A sensor that detects the plurality of combined lights through an optical system and acquires signals of the plurality of combined lights;
    Correction means for generating a signal that is a difference between the signals of the plurality of combined lights and that corrects a difference in the depth direction of the inspection object due to the configuration of the optical system and the sensor;
    The corrected signal or al of the plurality of the combined light, the tomographic imaging apparatus characterized by having a generating means for generating a vertical cross-sectional image with respect to the measurement light of the object.
  2. The tomographic imaging apparatus according to claim 1, wherein the difference is at least one of a resolution and an attenuation characteristic of each of the plurality of combined lights on the sensor.
  3. The difference is at least one of a characteristic of a spectroscope in the tomographic imaging apparatus, a characteristic of a light source in the tomographic imaging apparatus, and a difference in length of a reference light path of each of the plurality of combined lights. The tomographic imaging apparatus according to claim 1, wherein the difference is based on the difference .
  4. The generating means is
    Generating a plurality of cross-sectional images corresponding to each of the corrected composite light signals,
    The tomographic imaging apparatus according to claim 1 , wherein the cross-sectional image is generated by adjusting a contrast of the plurality of cross-sectional images .
  5.   The tomographic imaging apparatus according to claim 4, wherein the generation unit generates a cross-sectional image of a plane perpendicular to an irradiation direction of the plurality of measurement lights based on a wavelength spectrum.
  6. A tomography that combines a plurality of return lights and reference light obtained by irradiating the inspection object with a plurality of measurement lights, and acquires a cross-sectional image of the inspection object from the plurality of combined lights obtained by the combination A control device for an imaging device,
    Detecting a plurality of combined light through an optical system, a resulting unit preparative you get the signals of the plurality of combined light,
    Correction means for generating a signal that is a difference between the signals of the plurality of combined lights and that corrects a difference in the depth direction of the inspection object due to the configuration of the optical system and the sensor;
    The corrected signal or al of the plurality of the combined light, the control device of the tomography apparatus characterized by having a generating means for generating a vertical cross-sectional image with respect to the measurement light of the inspection object.
  7. Computer
    A tomography that combines a plurality of return lights and reference light obtained by irradiating the inspection object with a plurality of measurement lights, and acquires a cross-sectional image of the inspection object from the plurality of combined lights obtained by the combination A control device for an imaging device,
    Detecting a plurality of combined light through an optical system, a resulting unit preparative you get the signals of the plurality of combined light,
    Correction means for generating a signal that is a difference between the signals of the plurality of combined lights and that corrects a difference in the depth direction of the inspection object due to the configuration of the optical system and the sensor;
    The corrected signal or al of the plurality of the combined light, as a control device for tomographic imaging apparatus characterized by comprising a generating means for generating a vertical cross-sectional image with respect to the measurement light of the inspection object Computer program to make it function.
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