JP2014023951A - Optical interference tomographic device and image processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To confirm the success or failure of photographing after photographing.SOLUTION: A plurality of tomographic images of an object to be measured are generated on the basis of return light irradiated to the object to be measured and interference light obtained by interfering with reference light (S101, S103), a composite image is generated by compositing the plurality of generated tomographic images (S110), and in the case that the composite image is displayed in display means, image processing means updates the composite image displayed in the display means each time a new composite image is generated (S112).

Description

  The present invention relates to an optical coherence tomography apparatus and an image processing method, and more particularly to display of a tomographic image.

  Currently, optical coherence tomography (OCT: Optical Coherence Tomography) using multi-wavelength lightwave interference is used to obtain, for example, internal information in an endoscope or retina information in an ophthalmologic apparatus. The application field for is expanding. The optical coherence tomography apparatus applied to the eye is becoming an indispensable apparatus in a specialized retina outpatient as an ophthalmic apparatus.

  Such an optical coherence tomography apparatus is an apparatus that enables measurement light, which is low-coherent light, to be irradiated on a sample, and that backscattered light from the sample can be measured using an interference system. . And when applied to the eye, it is possible to capture a tomographic image of the eye to be examined with high resolution by scanning the measurement light on the eye to be examined. Yes.

  However, in the optical coherence tomography apparatus, speckle noise is generated due to interference between scattered lights caused by the structure of the measurement target. In addition, noise depending on the sensitivity of the detector (line sensor or photodiode) generated by suppressing the amount of light to reduce the load may occur.

  Therefore, as shown in Patent Document 1, a technique for improving the image quality of a tomographic image by scanning the same portion of the eye to be examined a plurality of times, performing alignment averaging after aligning a plurality of tomographic images obtained as a result of the scanning. Is disclosed.

  Further, the optical coherence tomography apparatus described in Patent Document 2 discloses a technique for improving the image quality of a tomographic image by combining a plurality of adjacent tomographic images after alignment.

  As described above, in order to obtain a high-quality tomographic image in the optical coherence tomography apparatus, for example, processing for reducing noise by aligning and synthesizing a plurality of obtained tomographic images is important.

JP 2010-110392 JP 2008-237238 A

However,
The optical coherence tomography apparatus described above is configured to display a tomographic image after alignment and synthesis processing of a plurality of tomographic images. Therefore, the examiner cannot refer to the tomographic image until the alignment and composition processing is completed, and it is difficult to determine the success or failure of imaging immediately after imaging.

  Also, when scanning and imaging the eye to be examined, scanning the same location of the eye to be examined multiple times and adding tomographic images to reduce speckle noise, random noise, etc., or imaging location of the eye to be examined In some cases, tomographic imaging is performed while moving. Furthermore, there are cases where tomographic imaging is performed while scanning the same location a plurality of times and moving the imaging location of the eye to be examined.

  However, there has been a problem that an image for confirming whether or not photographing is correct cannot be changed by the imaging method.

  The present invention has been made in view of the above problems, and an object thereof is to provide an optical coherence tomography apparatus capable of easily confirming the success or failure of tomographic imaging.

To achieve the above objective,
Generating means for generating a plurality of tomographic images of the object to be measured based on interference light obtained by causing interference between reference light and return light irradiated to the object to be measured;
Image processing means for generating a composite image by combining a plurality of tomographic images generated by the generating means;
Display control means for displaying the composite image on a display means,
The display control means updates the composite image displayed on the display means every time a new composite image is generated by the image processing means.

  According to the present invention, success or failure of photographing can be easily determined.

It is a figure which shows an example of an optical coherence tomography apparatus. It is a figure which shows an example of an image processing apparatus. It is a flowchart showing an example of operation | movement when displaying a tomographic image. It is a figure which shows the example of a display of an initial tomographic image. It is a figure which shows the example of a display of a reference | standard tomographic image. It is a figure which shows the example of a display of the partially synthesized tomographic image. It is a figure which shows the example of a display of the synthetic | combination tomographic image. It is explanatory drawing of a retina layer. It is a figure which shows the comparison in the vertical / horizontal direction of tomographic images. It is a figure which shows the comparison in the rotation direction of tomographic images.

[Embodiment 1]
A preferred embodiment of the present invention will be described. FIG. 1 is a diagram showing an example of an optical coherence tomography apparatus suitable for adapting to the fundus, cornea, and endoscope of the eye. In particular, a case where it is adapted to a fundus image will be described.

  An optical interference unit 100 includes a light source 101 that is a low coherence light source that emits near-infrared light. The light emitted from the light source 101 propagates through the optical fiber 102 a and is branched into measurement light and reference light by the light branching unit 103. The measurement light branched by the light branching unit 103 enters the optical fiber 102 b and is guided to the scanning optical system 200. On the other hand, the reference light branched by the light branching unit 103 enters the optical fiber 102 c and is guided to the reflection mirror 113.

  The reference light incident on the optical fiber 102c is emitted from the fiber end, enters the dispersion compensation optical system 112 via the collimating optical system 111, and is guided to the reflection mirror 113. The reference light reflected by the reflection mirror 113 follows the reverse optical path and enters the optical fiber 102c again. The dispersion compensating optical system 112 corrects the dispersion of the optical system in the scanning optical system 200 and the eye E to be measured. The reflection mirror 113 is configured to be driven in the optical axis direction by an optical path length control unit 114 (not shown), and can change the optical path length of the reference light relative to the optical path length of the measurement light. . On the other hand, the measurement light incident on the optical fiber 102b is emitted from the end of the fiber. The light source 101 and the optical path length control unit 114 are controlled under the control of a control unit 130 (not shown).

  Next, the scanning optical system 200 will be described. The scanning optical system 200 is an optical system configured to be movable relative to the eye E. A drive control unit 205 (not shown) of the scanning optical system is configured to drive the scanning optical system 200 in the vertical and horizontal directions with respect to the eye axis of the eye E. For example, in the case of an endoscope, the scanning optical system 200 is provided at the distal end portion of the fiberscope.

  Then, the light emitted from the fiber end of the optical fiber 102 b is made substantially parallel by the optical system 202 and enters the scanning unit 203. The scanning unit 203 has two galvanometer mirrors that can rotate the mirror surface, one of which changes the light in the horizontal direction, the other of which polarizes the light in the vertical direction, and is incident under the control of the drive control unit 205. Is polarized. As a result, the scanning unit 203 can scan in two directions, ie, the main scanning direction in the paper plane and the sub-scanning direction perpendicular to the paper plane. The light scanned by the scanning unit 203 forms an illumination spot on the retina Er of the eye E via the lens 204. When the scanning unit 203 receives in-plane deflection, each illumination spot moves on the retina Er. The reflected light at the illumination spot position follows the reverse optical path and enters the optical fiber 102 b and returns to the light branching unit 103.

  As described above, the reference light reflected by the reflection mirror 113 and the measurement light reflected from the retina Er to be examined are returned to the light branching unit 103 as return light to generate optical interference. The light that interferes with each other passes through the optical fiber 102 d, and the interference light emitted to the lens 122 is substantially collimated and enters the diffraction grating 123. The diffraction grating 123 has a periodic structure and separates the input interference light. The split interference light is imaged on the line sensor 125 by the imaging lens 124 capable of changing the in-focus state. The line sensor 125 is connected to the image processing apparatus 300.

  FIG. 2 is a diagram for explaining the image device 300.

  As shown in FIG. 2, the image apparatus 300 includes a generation unit 301 as a generation unit. The present embodiment is an optical coherence tomography apparatus using a Fourier domain method, and generates a tomographic image of the retina by Fourier transforming the output data of the line sensor 125 by the generation unit 301. The generation unit 301 is connected to a display control unit 310 serving as a display control unit, and is configured to display the generated tomographic image.

  Further, the image apparatus 300 includes a selection unit 302 as selection means for evaluating and selecting the image quality of the generated tomographic image. Based on the luminance value of the tomographic image generated by the generating unit 301, it is possible to calculate the evaluation value of the image quality of the tomographic image. Further, the selection unit 302 is configured to determine a reference tomographic image based on the calculated evaluation value and display the reference tomographic image on a monitor 320 as a display unit via the display control unit 310.

  An alignment unit 303 as an alignment unit can detect the positional relationship between the reference tomographic image and an arbitrary tomographic image, and outputs the aligned tomographic image to an image processing unit 304 as an image processing unit.

  The image processing unit 304 performs processing for reducing noise in the tomographic image generated by the generation unit 301. Alternatively, a process for increasing the contrast is performed. In an example of the present embodiment, a plurality of tomographic images are averaged to generate a tomographic image with improved image quality. Here, increasing the image quality means increasing the S / N ratio by reducing image noise or increasing the contrast of the image. The combined image processing unit 304 is connected to the display control unit 310 and configured to display the combined tomographic image on the monitor 320. The image processing unit 304 is not limited to such processing, and may perform other processing for reducing noise and improving contrast on the tomographic image. For example, sharpening processing for amplifying the amplitude of the high-frequency component of the tomographic image, noise reduction processing for removing isolated shadows, or the like may be performed.

  The display control unit 310 is connected to the monitor 320 and can display an arbitrary tomographic image input from the processing unit. As described above, the optical coherence tomography apparatus includes the optical interference unit 100, the scanning optical system 200, and the image processing apparatus 300, and each component is controlled under the control of the control unit 130. The control unit 130 includes a CPU 140 (not shown) and executes an operation by expanding the control program 150 in a RAM 160 (not shown). In addition, the optical interference unit 100, the scanning optical system 200, and the image processing apparatus 300 may each be configured with a control unit configured with a CPU, a GPU, and the like, and controlled by individual programs.

  Further, at least a part of each part of the image processing apparatus 300 may be realized as an independent apparatus. Alternatively, it may be implemented as software that implements its function by being installed in one or a plurality of computers and executed by a CPU 330 (not shown) of the computer. In this embodiment, each unit is realized by software and installed in the same computer.

  The CPU 330 controls the entire computer using programs and data stored in a RAM 3302 (not shown) and a ROM 3303 (not shown). Further, the execution of software in each part is controlled to realize the function of each part.

  The RAM 3302 has an area for temporarily storing programs and data loaded from the storage medium drive 3308 and a work area necessary for the CPU 2330 to perform various processes.

  The ROM 3303 generally stores computer programs and setting data.

  The image processing apparatus 300 can also be configured as an electric circuit with an image processing board.

  A control method of the control unit 130 for capturing a plurality of tomographic images of the fundus of the eye to be examined in this optical coherence tomography apparatus will be described.

  First, the examiner seats a patient in front of the optical coherence tomography apparatus based on the present embodiment and starts OCT imaging. Light emitted from the light source 101 passes through the optical fiber 102 a and is divided into measurement light directed to the eye to be examined and reference light directed to the reference mirror 113 by the light branching unit 103.

  The measurement light traveling toward the eye to be examined passes through the optical fiber 102 b and exits from the end of the fiber, is approximately parallelized by the optical system 202, and enters the scanning unit 203. The scanning unit 203 includes a galvanometer mirror, and the measurement light deflected by the mirror irradiates the fundus of the eye to be examined via the optical system 204. Then, the reflected light reflected by the eye to be examined follows the reverse path and is returned to the light branching unit 103.

  On the other hand, the reference light traveling toward the reference mirror passes through the optical fiber 102 c and is emitted from the end of the fiber, and reaches the reference mirror 113 through the collimating optical system 111 and the dispersion compensation optical system 112. The reference light reflected by the reference mirror 113 follows the reverse path and is returned to the light branching unit 103.

  The measurement light and the reference light that have returned to the optical branching unit 103 interfere with each other, enter the optical fiber 102d as interference light, are substantially collimated by the optical system 122, and enter the diffraction grating 123. The interference light input to the diffraction grating 123 forms an image on the line sensor 125 by the imaging lens 124, and an interference signal at one point on the fundus of the eye to be examined can be obtained.

  The interference signal acquired by the line sensor 125 is output to the image processing apparatus 300, and the generation unit 301 performs wave number conversion and fast Fourier transform (FFT) processing to obtain a tomographic image in the depth direction at one point on the eye fundus. Is visualized as

  After acquiring a tomographic image at one point on the fundus of the eye to be examined, the scanning unit 203 drives the galvanometer mirror to generate another point of interference light on the fundus of the eye to be examined. The interference light at the other point passes through the line sensor 125 and is formed as a tomographic image in the depth direction at another point on the fundus of the eye to be examined. By continuously driving the galvanometer mirror by the scanning unit 203, one tomographic image of the fundus of the eye to be examined can be generated.

  A first mode in which the same portion of the eye to be examined is scanned a plurality of times to acquire a tomographic image at the same portion; a second mode in which the scanning position of the eye to be examined is moved to capture a plurality of tomographic images; and There is a third mode in which the same location is scanned a plurality of times and the scanning position of the eye to be examined is moved to capture tomographic images at a plurality of locations. Since the eye is finely moved and shifted and the same part cannot be imaged in a strict sense, scanning the same part of the eye to be examined a plurality of times means that the galvanometer mirror has the same scanning orbit and is scanned a plurality of times.

  The following describes an example of the first mode.

  The scanning unit 203 generates a single tomographic image of the eye to be examined, and then generates a plurality of tomographic images with the same scanning trajectory. For this reason, scanning at substantially the same position on the fundus is repeated. By this multiple scans, the generation unit 301 can generate a plurality of tomographic images at substantially the same part of the fundus of the eye to be examined.

  Next, in the optical coherence tomography apparatus according to the present embodiment, a procedure for displaying a tomographic image before completion of composition before completion of alignment and composition processing of a plurality of tomographic images will be described with reference to FIG. .

  The generating unit 301 generates the first tomographic image of the fundus oculi to be examined in step S101, and then outputs the generated tomographic image to the display control unit 310. The display control unit 310 displays the input tomographic image on the monitor 320 (step S102).

  As shown in FIG. 4, the first tomographic image 321 displayed on the monitor 320 often has a lot of noise and the contrast is not clear. However, the first tomographic image 321 often has a sufficient image quality for the purpose of confirming the positional relationship of the retina on the imaging region or image. Therefore, the examiner can determine the success or failure of imaging to some extent when the first tomographic image 321 is displayed in step S102.

  Then, by scanning the galvanometer mirror 203 a plurality of times with the same locus, interference light for obtaining a plurality of tomographic images at substantially the same part of the fundus of the eye to be examined is obtained. Then, the generation unit 301 generates a plurality of tomographic images at substantially the same part of the fundus of the eye to be examined (step S103). The plurality of tomographic tomographic images generated by the generation unit 301 are output to the selection unit 302 in order to determine a reference image necessary for alignment.

  The selection unit 302 calculates an evaluation value for evaluating the image quality of each tomographic image for all input tomographic images based on the luminance value of each pixel of the tomographic image (step S104). As a method for calculating the evaluation value, all pixels constituting the tomographic image are classified for each luminance value (calculation of a histogram), and the evaluation value is calculated by counting the number of pixels having luminance values in a predetermined range. Is used. This method uses the characteristic that each layer constituting the retina is concentrated in a certain luminance range on the tomographic image, and the image quality of the tomographic image can be evaluated by the size of the obtained index.

  In the above description, the evaluation value calculation method based on the luminance range of the tomographic image has been exemplified. However, it is also possible to obtain the evaluation value using another method. For example, the contrast ratio may be calculated based on the luminance value of the tomographic image and used as a quality index, or the signal-to-noise (S / N) ratio may be calculated based on the luminance value of the tomographic image and used as the evaluation value. good.

  After calculating the evaluation value of each tomographic image, the selection unit 302 identifies a tomographic image showing the highest image quality from among the tomographic images, and selects the tomographic image as a reference tomographic image for alignment ( Step S105). The selection unit 302 also outputs the selected reference tomographic image to the display control unit 310. The display control unit 310 displays the input reference tomographic image on the monitor 320 (step S106).

  As shown in FIG. 5, the noise amount of the reference tomographic image 322 displayed on the monitor 320 is equal to that of the first tomographic image 321, but the contrast is clearer than that of the first tomographic image 321. The reference tomographic image 322 is more appropriate than the first tomographic image 321 in determining the success or failure of imaging. However, there is a possibility that the time until the final composite tomographic image is displayed is extended by the time required for the display processing of the reference tomographic image 322. Therefore, the display control unit 310 may omit displaying the reference tomographic image 322 (Step S106).

  Since the tomographic image at the same location is always displayed in the first mode, it is preferable to display the reference tomographic image 322 after displaying the first tomographic image 321. On the other hand, in the third mode, since many tomographic images with different scanning positions are displayed, there are cases where the reference tomographic image 322 is displayed, which may disturb the confirmation. Therefore, it is preferable to omit displaying the reference tomographic image 322 in the third mode.

  In addition, the photographer selects a mode in which the reference tomographic image 322 is displayed after the first tomographic image 321 is displayed and a mode in which the reference tomographic image 322 is not displayed after the first tomographic image 321 is displayed. be able to.

  Finally, the selection unit 302 outputs the selected reference tomographic image 322 and all tomographic images other than the reference tomographic image to the alignment unit 303.

  The alignment unit 303 executes a position and shape detection process of the retinal layer on each tomographic image 322 in order to obtain a positional relationship between the input reference tomographic image 322 and the other tomographic images. First, the alignment unit 303 detects the shape and position of the ILM (inner boundary membrane) and RPE (retinal pigment epithelium) on the reference tomographic image 322 (step S107).

  As shown in FIG. 8, the ILM is the boundary between the vitreous body and the retina located at the top of the retina. In general, since the optical reflectance of the retina is higher than that of the vitreous body, the optical interference signal intensity of the retina in the optical coherence tomography apparatus is larger than that of the vitreous body. For this reason, the luminance of the tomographic image taken by the optical coherence tomography apparatus greatly changes in the ILM that is the boundary between the vitreous body and the retina. The alignment unit 303 can specify the shape and position of the ILM by detecting this change in luminance information.

  On the other hand, as shown in FIG. 8, the RPE is a layer of epithelial cells located at the boundary between the retina of the eye and the choroid, and in the tomographic image taken by the optical coherence tomography apparatus, the layer showing the highest brightness value. Known as. The misregistration detection unit 303 can detect the shape and position of the RPE based on this high-luminance image information in the same manner as the ILM.

  Next, the alignment unit 303 detects the shapes and positions of the ILM and RPE for the tomographic images other than the input reference tomographic image 322 in the same manner as the reference tomographic image 322 (step S108).

  The tomographic image in which the shapes and positions of the ILM and RPE layers are detected is calculated in positional relationship (positional deviation amount) with the reference tomographic image 322 by the alignment unit 303 (step S109). For example, as shown in FIG. 9, by comparing the shape and position of the ILM and RPE of the reference tomographic image 322 and the target tomographic image, how much the target tomographic image is shifted in the vertical and horizontal directions with respect to the reference tomographic image 322 ( x and y) can be determined. Further, as shown in FIG. 10, by comparing the inclinations of the ILM and RPE of the reference image 322 and the target tomographic image, how much the target tomographic image is shifted in the rotation direction with respect to the reference tomographic image 322 (r). Can also be requested.

  The respective tomographic images are aligned based on the vertical and horizontal positional deviation amounts and the rotational positional deviation amounts thus obtained, and are output to the image processing unit 304.

  In this embodiment, the displacement amount between tomographic images is obtained by detecting the shape and position of the ILM and RPE, but the retinal layer or layer boundary other than the ILM and RPM is detected, and the shape and position thereof are detected. The amount of positional deviation between tomographic images may be obtained based on the above. Further, the positional deviation amount may be obtained by comparing luminance values of tomographic images instead of comparing the shapes and positions of the retinas. For example, the amount of positional deviation between tomographic images can be obtained by calculating a difference in luminance value between tomographic images and searching for a position where the difference is the smallest.

  The image processing unit 304 performs an averaging process on the plurality of aligned tomographic images (step S110). Addition averaging process is a general averaging process that adds the luminance values of tomographic images, divides the sum by the number of tomographic images used for the addition, and uses the result as the luminance value of the new tomographic image. It is. In this embodiment, the tomographic images are synthesized by this averaging process, but the tomographic images may be synthesized by using other methods. For example, a plurality of tomographic images can be synthesized using a median (median) filter.

  Through the processing from step S108 to step S110, the composition processing of the reference tomographic image 322 and one tomographic image is completed. Then, the image processing unit 304 determines whether there is a tomographic image that has not yet been combined (step S111).

  When an unsynthesized tomographic image remains, the image processing unit 304 outputs the already synthesized tomographic image (partially synthesized tomographic image) to the display control unit 310 at that time, and the display control unit 310 The input partially synthesized tomographic image is displayed on the monitor 320 (step S112). As shown in FIG. 6, the noise amount of the partially combined tomographic image 323 displayed on the monitor 320 is smaller than that of the first tomographic image 321 and the reference tomographic image 322, and the contrast is clear.

  In determining the success or failure of imaging, the partially combined tomographic image 323 is more appropriate than the first tomographic image 321 and the reference tomographic image 322. However, there is a possibility that the time until the final composite tomographic image is displayed is extended by the time required for the display processing of the partially synthesized tomographic image 323. Therefore, the display control unit 310 may omit displaying the partially synthesized tomographic image 323 (step S112).

  In the first mode, a partially synthesized tomographic image 323 is displayed. In the third mode, since the location being scanned changes, there are cases where a large number of images are put in the way of confirmation, and only the tomographic images for which the synthesis has been completed are displayed.

  Further, the photographer can select a mode for displaying the partially synthesized tomographic image 323 and a mode for displaying only the tomographic image for which the synthesis has been completed.

  After the display of the partially combined tomographic image 323, the image processing unit 304 sets the partially combined tomographic image 323 as the reference image 322 in order to combine with the next tomographic image (step S113). The series of processing from step S108 to step S111 is repeated. By repeating the above processing, the latest partially synthesized tomographic image 323 is sequentially displayed on the monitor 320.

  Then, after the synthesis of all the tomographic images is completed, the image processing unit 304 outputs the synthesized tomographic image to the display control unit 310. The display control unit 310 displays the combined tomographic image 324 input as shown in FIG. 7 on the monitor 320 (step S114).

  Although an example in which images are sequentially displayed on the monitor 320 has been described, a plurality of images may be displayed on the monitor 320. Further, other monitors may be prepared and different images may be displayed on each monitor. When displaying a plurality of images, comparison between the images is facilitated.

  In the second mode, when the tomographic image generated by the generating unit 301 is combined, the image processing unit 304 adds the tomographic images captured before and after in time. The reference tomographic image in this case is a tomographic image to be added. In addition, the tomographic images generated by the generation unit 301 displayed on the monitor 320 via the display control unit 310 are displayed in the order in which they were captured. The tomographic image processed by the image processing unit 304 is displayed on the monitor 320 alternately with the tomographic image generated by the generation unit 301.

  Furthermore, in the second and third modes, the first tomographic image captured by the selection unit 302 and the last tomographic image captured are selected, and the tomographic image selected by the selection unit 302 is also monitored. It can also be configured to display on 320. This is because the eyes are curved, and it is easy to determine whether or not the photographing is correct by displaying the tomographic image captured first and the tomographic image captured last.

  As described above, the optical coherence tomography apparatus according to the present embodiment is configured to be able to display a tomographic image capable of determining success or failure of imaging during image processing of the tomographic image. Therefore, it is possible to determine success or failure of shooting immediately after shooting. Furthermore, it is possible to determine the success or failure of the shooting with an image with improved image quality as time passes.

(Other examples)
Although the embodiment has been described in detail above, the present invention can take an embodiment as a system, apparatus, method, program, storage medium, or the like. Specifically, the present invention may be applied to a system composed of a plurality of devices, or may be applied to an apparatus composed of a single device.

  In the present invention, the functions of the above-described embodiments are achieved by supplying a software program directly or remotely to a system or apparatus, and the computer of the system or apparatus reads and executes the supplied program code. Including the case.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, and the like.

  Examples of the computer-readable storage medium for supplying the computer program include the following. For example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card, ROM, DVD (DVD-ROM, DVD- R).

  As another program supply method, a client computer browser is used to connect to a homepage on the Internet, and the computer program of the present invention is downloaded from the homepage to a recording medium such as a hard disk. In this case, the downloaded program may be a compressed file including an automatic installation function. It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the present invention.

  Further, the program of the present invention may be encrypted, stored in a storage medium such as a CD-ROM, and distributed to users. In this case, a user who has cleared a predetermined condition is allowed to download key information for decryption from a homepage via the Internet, execute an encrypted program using the key information, and install the program on the computer. You can also.

  In addition to the functions of the above-described embodiment being realized by the computer executing the read program, the embodiment of the embodiment is implemented in cooperation with an OS or the like running on the computer based on an instruction of the program. A function may be realized. In this case, the OS or the like performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

  Furthermore, the program read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, so that part or all of the functions of the above-described embodiments are realized. May be. In this case, after a program is written in the function expansion board or function expansion unit, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing based on the instructions of the program.

DESCRIPTION OF SYMBOLS 100 Optical interference part 101 Light source 200 Scanning optical system 300 Image processing apparatus 301 Generation part 302 Selection part 303 Positioning part 304 Image processing part 310 Display control part 320 Monitor

Claims (5)

Generating means for generating a plurality of tomographic images of the object to be measured based on interference light obtained by causing interference between reference light and return light irradiated to the object to be measured;
Image processing means for generating a composite image by combining a plurality of tomographic images generated by the generating means;
Display control means for displaying the composite image on a display means,
The optical coherence tomography apparatus, wherein the display control unit updates the composite image displayed on the display unit every time a new composite image is generated by the image processing unit. Evaluation means for evaluating the image quality of a plurality of tomographic images generated by the image generation means;
Selection means for selecting a reference image that is a reference for alignment when generating a composite image based on the evaluation by the evaluation means;
The optical coherence tomography apparatus according to claim 1, wherein the image processing unit synthesizes a plurality of tomographic images using the reference image as a reference for alignment. Evaluation means for evaluating the image quality of a plurality of tomographic images generated by the image generation means;
A selection means for selecting a tomographic image to be displayed based on the evaluation by the evaluation means;
The optical coherence tomography apparatus according to claim 1, wherein the display control unit updates the display with the generated composite image after displaying the selected tomographic image on the display unit.   The optical coherence tomography apparatus according to claim 1, wherein the image processing unit generates a composite image by performing an averaging process. An image processing method for image processing of a plurality of tomographic images in a measurement object,
An acquisition step of acquiring a plurality of tomographic images of the object to be measured based on interference light obtained by causing interference between reference light and return light irradiated to the object to be measured;
An image processing step of generating a composite image by combining the plurality of tomographic images;
A display control step of displaying the composite image on a display means,
In the display control step, the composite image displayed on the display means is updated every time a new composite image is generated by the image processing step.

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