JP2010025943A - Tomographic imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tomographic imaging apparatus which requires no driving mechanism for moving reference mirror to correctly detect amplitude of interference signal, while having extremely simple configuration. <P>SOLUTION: In the tomographic imaging apparatus, an interferometer device section includes light irradiation optical system part for analyte 231 and the reference mirror 242, dual light guide of branched signal light and reference light, two Young interferometer parts, two multi-pixel image sensors 252A and B, and light intensity distribution differencing means 282 for computing difference of light intensity distribution signal obtained by both of these multi-pixel image sensors, which introduces balance detection approach to compensate for bias components including fluctuation of light source. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention applies a technique based on optical coherence tomography (hereinafter referred to as OCT) configured by combining a light source that outputs light with a short coherence length and an equal optical path length type interferometer such as a Michelson interferometer. Alternatively, the present invention relates to a tomographic image apparatus used when obtaining a tomographic image of a subject in the field of industry or the like, and particularly relates to a tomographic image device that does not require a reference plane scanning mechanism for obtaining image data in the depth direction of the subject Is.

  2. Description of the Related Art In recent years, devices that capture tomographic images of a subject using an OCT technique are known in the field of imaging a subject for medical use or industrial use, particularly in the field of electronic endoscopes.

  Since this tomographic image apparatus using OCT uses light as a detection probe, there is no problem that the subject is exposed to X-ray irradiation unlike the conventional X-ray imaging apparatus, and in particular, the subject seems to be a human body. In this case, it is extremely preferable. In addition, a large-scale apparatus such as CT or MRI is not required, and the test of the subject can be easily performed. Therefore, the cost burden and physical burden on the subject can be reduced. preferable.

In addition, this tomographic imaging apparatus using OCT obtains interference wave information at each position in the depth direction of the subject by utilizing the low coherence of light having a broad spectrum width. Reflected light from the inside of the specimen can be detected with a spatial resolution on the order of μm, and the measurement resolution can be greatly improved as compared with a conventional X-ray imaging apparatus.
Such a tomographic image apparatus using OCT having many excellent characteristics is disclosed, for example, in Non-Patent Document 1 below.

FIG. 5 schematically shows a conventional tomographic image apparatus. That is, the output from the low coherence light source 310 is made incident on the optical fiber 321. The light beam traveling in the optical fiber 321 is separated into two light beams by the 2 × 2 coupler 325, one of which is guided to the subject 331 side by the optical fiber 322, and the other is guided to the reference mirror 342 side by the optical fiber 323. It is burned.
An objective condensing lens 332 is provided at the subsequent stage of the light emitting end of the optical fiber 322, and the light beam is condensed on the subject 331 by the lens 332.

  On the other hand, the light emitted from the light emitting end of the optical fiber 323 is applied to the reference mirror 342 via the collimator lens 341. The reference mirror 342 is movable in the optical axis direction, and the optical fiber 322 is provided. The reference mirror 342 is located at a position where the optical path length from the light exit end of the optical fiber to the observation position in the depth direction of the subject 331 and the optical path length from the light exit end of the optical fiber 323 to the reference mirror 342 are equal to each other. It has been moved. As a result, a so-called Michelson interferometer capable of causing optical interference even with low coherent light is constructed, and interference wave information at each position in the depth direction of the subject 331 can be obtained.

  The reflected light from the observation position of the subject 331 and the reflected light from the reference mirror 342 travel back in their irradiation paths, and are combined by the 2 × 2 coupler 325 to interfere with each other, and the interference light is an optical fiber. The interference wave information is detected by the photodetector 352 by reaching the photodetector 352 via the line 324. Thereafter, the interference wave information detected by the photodetector 352 is converted into an electrical signal, which is input to the computer 365 via the amplifier 362, the band pass filter 363, and the A / D converter 364, and subjected to predetermined image processing. Will be.

  Such an OCT technique is generally referred to as TDOCT (Time Domain OCT). However, a drive mechanism that repeatedly moves the reference mirror in the optical axis direction is required, which increases the size and complexity of the apparatus.

  Thus, a technique called SDOCT (Spectral Domain OCT) has been developed that does not require a drive mechanism for moving the reference mirror. This SDOCT is obtained by arranging, for example, a diffraction grating and a Fourier transform optical system on a surface on which reflected light (signal light) from the subject and reflected light (reference light) from a reference mirror are superimposed, and the obtained interference wave. By performing a Fourier transform operation on the information, a tomographic image of the subject can be obtained without driving the reference mirror.

As such SDOCT technology, the one described in Patent Document 1 below is known.
Note that the technique described in Patent Document 1 further employs an angular dispersion imaging method that can directly detect an envelope of an interference signal.

JP 2001-272332 A

Optics 32 (4) (2003): Manabu Sato, Naohiro Tanno

However, in the technique described in Patent Document 1 described above, in the interference signal representing the light intensity distribution of the interference light obtained by the photodetector, the cosine function having the phase difference Δl between the signal light and the reference light as a variable is multiplied as weight. Therefore, when the angle θ of the function is π / 2, 3π / 2, etc., accurate amplitude detection is impossible.
Further, various optical members such as a diffraction grating are disposed between the output surface of the signal light and the reference light and the light detection surface, and an apparatus having a simpler configuration has been desired.

  The present invention has been made in view of the above circumstances, and provides a tomographic image apparatus capable of accurately detecting the amplitude of an interference signal while not requiring a drive mechanism for moving a reference mirror and having a very simple configuration. It is intended.

The tomographic imaging apparatus of the present invention includes a light source that emits light having low coherence,
A light irradiation optical system configured to divide the light emitted from the light source into two parts, irradiate one of the objects to the subject and irradiate the other to the reference mirror;
The signal light from the subject based on the light irradiation from the light irradiation optical system is demultiplexed, and the second signal light causes a predetermined phase shift with respect to the demultiplexed first signal light. A first light guide member that guides each to different light exit ends;
The reference light from the reference mirror based on the light irradiation is demultiplexed, and the second reference light causes a predetermined phase shift with respect to the demultiplexed first reference light, so that each light is different from each other. A second light guide member leading to the exit end;
Light of interference light caused by the first signal light emitted from the light emission end of the first light guide member and the first reference light emitted from the light emission end of the second light guide member A first multi-pixel imaging device for obtaining an intensity distribution signal;
Light of interference light caused by the second signal light emitted from the light emission end of the first light guide member and the second reference light emitted from the light emission end of the second light guide member A second multi-pixel imaging device for obtaining an intensity distribution signal;
A light intensity distribution difference means for obtaining a difference between the light intensity distribution signal obtained by the first multi-pixel image sensor and the light intensity distribution signal obtained by the second multi-pixel image sensor;
It is characterized by comprising.

  In this case, each emission end of the first light guide member and the second light guide member functions as a point light source, the emission end corresponding to the first multi-pixel imaging element, and the first The positional relationship between the multi-pixel image sensor and the positional relationship between the emission end corresponding to the second multi-pixel image sensor and the second multi-pixel image sensor each constitute a Young interferometer. Deploy.

  Moreover, the first light guide member and the second light guide member are made of, for example, optical fibers.

  In addition, an objective lens is inserted between the emission ends of the first light guide member and the second light guide member and the multi-pixel image sensor, and the objective lens is placed on the multi-pixel image sensor. In the above, it is preferable that the position is set so that an overlapping area between the corresponding signal light and the reference light from each emission end becomes large.

  In addition, it is preferable that the apparatus further includes an optical scanning unit for scanning light from the light source in a predetermined direction along the surface of the subject.

  Further, it is preferable that the reference mirror is movable in the optical axis direction of the reference mirror, and the measurement range in the subject depth direction is variable.

  Further, it is preferable that the multi-pixel imaging device is movable in the optical axis direction of the multi-pixel imaging device, and the sampling pitch in the subject depth direction is variable.

  Further, tomographic image information calculating means for analyzing and calculating tomographic image information of the subject based on an output signal from the multi-pixel imaging device and scanning timing of the optical scanning means, and a tomogram obtained by the tomographic image information calculating means It is preferable to provide tomographic image display means for displaying video information.

In the tomographic image apparatus of the present invention, basically, Young's interferometer (or common path interferometer) in which the light emitting member emitting light that guides the signal light from the subject and the reference light from the reference mirror is regarded as a point light source. ), The signal light and the interference light are caused to interfere with each other, and the interference signal is detected by the multi-pixel imaging device, thereby obtaining tomographic image information in the depth direction of the subject.
In general, Young's interferometers (or common path interferometers) are known to interfere with two lights from the same light source that do not have a time delay, and if the light source has a sufficiently long coherence length, the interference The signal is a sine wave.

  Therefore, when the present inventor applies the concept of Young's interferometer (or common path interferometer) to OCT in which a low-coherence light source is an essential element and a time delay occurs between two light beams that interfere with each other, The present inventors have found that an extremely simple tomographic image apparatus can be configured, and have made the present invention.

  That is, since low coherence light is used in OCT, when the concept of Young's interferometer (or common path interferometer) is introduced, it is extremely centered on the image sensor surface position where the optical path difference between the two lights is zero. Interference fringes can be generated only in a narrow range. Therefore, since the signal light has a time delay amount corresponding to the depth position of the subject with respect to the reference light, the image information corresponding to the depth position is reduced from the image sensor. A signal obtained by convolution integration with the interference wave information of the interference light source itself is obtained. By subjecting this signal to filtering processing and signal processing using a log amplifier or the like, and to harmonize the signal, it is possible to obtain subject tomographic image information similar to that of conventional TDOCT.

  Accordingly, a moving scanning mechanism in the optical axis direction of the reference mirror, which is essential in the conventional TDOCT, is not required, and a light dispersion element such as a diffraction grating used in the conventional SDOCT is not required. Thus, an OCT apparatus that can accurately detect the amplitude of the interference signal can be obtained.

  Further, in addition to this, the tomographic image apparatus of the present invention can cancel the bias component including fluctuation of the light source by introducing a balance detection method, and only the interference signal component can be theoretically doubled. The effect that can be produced.

It is the schematic which shows the tomographic image apparatus which concerns on the basic reference example which is not contained in this invention. It is the schematic which shows the tomographic image apparatus which concerns on the other reference example which is not contained in this invention. 1 is a schematic diagram showing a tomographic imaging apparatus according to an embodiment of the present invention. It is a schematic diagram for demonstrating the one part effect | action of FIG. It is the schematic which shows the tomographic image apparatus which concerns on a prior art.

  Hereinafter, a tomographic imaging apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing a tomographic imaging apparatus according to a basic reference example not included in the present invention.
The tomographic imaging apparatus according to this reference example is applied to a medical endoscope, and includes a light source unit, an interferometer device unit, and a signal processing unit.

  The light source unit includes a low coherence light source 111. In addition, the interferometer device unit is composed of a light irradiation optical system unit, a light guide unit for signal light and reference light, and a Young interferometer unit, and constitutes a so-called unbalanced Michelson interferometer device as a whole. is doing. The light irradiation optical system unit includes four optical fibers 121, 122, 123, and 124, an optical coupler (2 × 2 coupler) 125, first and second optical circulators 132 and 143, and a front stage of the subject 131. The light guide member 133 is arranged, a collimator lens 141, and a reference mirror 142. The light guide for signal light and reference light is composed of two optical fibers 126 and 127. Furthermore, Young's interferometer unit is a multi-channel that obtains interference signals by imaging the emission ends 126A and 127A of the two optical fibers 126 and 127, each of which can be regarded as a point light source, and interference fringes carrying subject information. A detector 152 is provided.

  The signal processing unit includes an amplifier 162, a band pass filter 163, an A / D converter 164, an image processing unit 165, and an image display unit 166.

The operation of the basic tomographic image apparatus according to the reference example will be described below.
The low coherence light source 111 is a light source that emits light having a wide spectrum width (wide wavelength band) in the near-infrared region (hereinafter also referred to as low coherence light), and is, for example, an SLD (Super-luminescent diode) or ASE. (Amplified
Spontaneous emission). The light emitted from the low coherence light source 111 is condensed on the incident end face of the optical fiber 121 by a condensing lens (not shown) and transmitted to the optical coupler (2 × 2 coupler) 125 through the optical fiber 121.

  The transmitted low coherence light is divided into two by the optical coupler 125, one being transmitted to the optical fiber 122 and the other being transmitted to the optical fiber 123. Note that a photodetector 112 for detecting the light intensity of the low coherence light source 111 is connected to the optical coupler (2 × 2 coupler) 125 via an optical fiber 124.

The low coherence light transmitted through the optical fiber 122 is condensed and irradiated onto the subject 131 (human body) via the first optical circulator 132 and the light guide member 133.
The low coherence light irradiated to the subject 131 is reflected from each position in the depth direction of the subject 131 to become signal light, travels in the irradiation path in the reverse direction, and Young's interference is caused by the first optical fiber 126. Guided to the meter.

On the other hand, the low coherence light transmitted through the optical fiber 123 is applied to the reference mirror 142 via the second optical circulator 143 and the collimator 141.
The low coherent light (reference light) reflected from the reference mirror 142 travels in the irradiation path in the reverse direction, and is guided to Young's interferometer unit by the second optical fiber 127.

The signal light and reference light guided to Young's interferometer interfere with each other in this Young's interferometer, and image information in the depth direction of the subject is detected as a change in light intensity (light intensity distribution). Will be detected by the detector 152.
Thereafter, the light intensity distribution detected by the multi-channel detector 152 is converted into an electrical signal, which is input to the image processing unit 165 via the amplifier 162, the band pass filter 163, and the A / D converter 164, and the subject 131. Depth direction video information is generated, and the generated depth direction video information is displayed on the image display unit 166.

Note that the image processing unit 165 performs envelope processing on the one-dimensional light intensity signal output from the multi-channel detector 152 and carrying information in the depth direction of the subject 131. . That is, since the light intensity signal appears in the form of an AC signal, the negative component is folded and converted into a signal having only a positive component, and then the envelope is extracted to obtain a continuous light intensity signal. Yes.
Thereafter, the continuous light intensity signal is output to the image display unit 166, and a tomographic image of the subject 131 is displayed.

  In general, a light intensity distribution in the depth direction is obtained at each scanning point by an optical scanning means for scanning illumination light in a predetermined direction along the surface of the subject 131, and image processing is performed. The unit 165 performs image signal processing that connects the light intensity distributions in the depth direction of these points to generate a two-dimensional tomographic image signal.

  The Young interferometer section will be described in detail below.

  The signal light and the reference light guided to Young's interferometer as described above are emitted from the emission end 126A of the first optical fiber 126 and the emission end 127A of the second optical fiber 127. Here, since the fiber core diameters at the emission ends 126A and 127A of the optical fibers 126 and 127 are normally 9 to 10 μm, they can be regarded as point light sources. Here, the distance between the centers of the output ends 126A and 127A is set to l, and a multi-channel arranged in parallel to this line segment (this direction is defined as the X direction) from the line segment connecting the output ends 126A and 127A. When the distance to the detector 152 is set to b, on this multi-channel detector 152, the optical path length S1 of the reference light from the output end 126A and the signal light from the output end 126A according to the position x in the X direction. An optical path difference as shown in the following formula (1) occurs between the optical path length S2 and the optical path length S2.

  By the way, in the generally known Young's interferometer, the light from the light source is handled as having a short wavelength and sufficiently long coherence length, so when the same phase wavefront from the same light source is split into two The intensity distribution f (x) on the evaluation surface (image sensor surface) is a sine wave as represented by the following equation (2). Here, λ is a wavelength used.

  On the other hand, when the light source is a low coherence light source used in OCT, if the phases of the light waves at the exit ends 126A and 127A of the optical fibers 126 and 127 match each other, the evaluation surface (imaging) The intensity distribution g (x) on the element surface is expressed by the following expression (3).

  That is, on the multichannel detector 152, interference fringes are generated only in a small region centered on the optical path difference 0.

  Furthermore, when the signal light has a time delay amount with respect to the reference light, the position where the interference fringe is generated is delayed by a time delay from the position where the optical path difference is 0, as is apparent from the development of the above equation (3). Appears at a position shifted by a predetermined amount in the X direction according to the amount (depth amount). As a result, video information corresponding to the depth of the subject 131 can be developed on the one-dimensional multi-channel detector 152.

  In the above reference example, the reference mirror 142 may be configured to be movable in the direction of the optical axis, whereby the detection range in the depth direction of the subject 131 can be changed.

  Further, in the above reference example, the multi-channel detector 152 may be configured to be movable in the optical axis direction, whereby the sampling pitch at the time of detection can be made variable.

  In addition, an objective condensing lens for condensing and irradiating illumination light to the subject 131 is provided at the tip of the light guide member 133, so that at least a part of the lens can be moved in the optical axis direction for observation. If it is configured to be able to focus on the position, it is possible to prevent the subject image from being blurred at the observation position.

  FIG. 2 is a schematic configuration diagram showing a tomographic image apparatus according to another reference example not included in the present invention. Since this reference example has the same configuration as that of the reference example of FIG. 1 except for Young's interferometer, the same members as those of FIG. The detailed explanation is omitted.

In this reference example, an objective lens 151 is disposed in Young's interferometer section.
In addition, the output ends 126A and 127A of the optical fibers 126 and 127 are arranged at positions symmetrical to each other with respect to the optical axis of the objective lens 151, and the signal light emitted from the output ends 126A and 127A and The diffusion / convergence state of the reference light is adjusted by the objective lens 151.

  As a result, the irradiation position of the signal light and the reference light on the multi-channel detector 152 can be set to an optimum position according to the specifications of the size of the multi-channel detector 152 and its resolution (number of pixels). As compared with the reference example of FIG. 1 described above, the amount of light in the area where the signal light and the reference light overlap on the multichannel detector 152 (interference area: hatched area in the figure) can be greatly increased.

  In particular, when the element surface of the multi-channel detector 152 is arranged at the focal plane position of the objective lens 151 (f in FIG. 2 is, for example, 50 mm), the interference region between the signal light and the reference light is that of the objective lens 151. The shape is symmetric with respect to the optical axis, and the position setting of the multichannel detector 152 and the like are facilitated.

  FIG. 3 is a schematic diagram showing a tomographic image apparatus according to an embodiment of the present invention. Since this embodiment has a number of configurations corresponding to the reference example of FIG. 1, in FIG. 3, members corresponding to those of FIG. 1 are denoted by reference numerals obtained by adding 100 to the reference numerals of FIG. (However, the same reference numerals are given to 162 to 166), and detailed description thereof is omitted.

  The difference of the present embodiment from the two reference examples described above is that the bias component including the fluctuation of the light source is canceled by introducing a balance detection technique.

  That is, as shown in FIG. 3, the signal light guided by the first optical fiber 226 is converted by the second optical coupler (3 dB coupler) 261 into the first signal light and the first signal light. The second signal light is subjected to phase modulation of ± π / 2, and the former is guided to the first output end 262A by the optical fiber 262, and the latter is guided to the second output end 263A by the optical fiber 263. . On the other hand, the reference light guided by the second optical fiber 227 is phase-shifted by ± π / 2 with respect to the first reference light and the first reference light by the third optical coupler (3 dB coupler) 271. The light is split into the modulated second reference light, the former is guided to the third emission end 272A by the optical fiber 272, and the latter is guided to the fourth emission end 273A by the optical fiber 273. Note that isolators 264 and 274 are connected to the optical couplers 261 and 271, respectively.

  The first exit end 262A, the third exit end 272A, and the first multi-channel detector 252A are first Young interferometers that function in the same manner as the Young interferometer of the reference example of FIG. Constitute. On the other hand, the second emission end 263A, the fourth emission end 273A, and the second multi-channel detector 252B are second Young's interference that functions in the same manner as the Young's interferometer of the reference example of FIG. Configure the total.

  The interference wave information detected by the first multi-channel detector 252A and the second multi-channel detector 252B is converted into an electric signal, and is then subtracted from each other by the difference calculator 282, similar to the above two reference examples. The tomographic image of the subject 231 is generated by being input to the image processing unit 165 via the amplifier 162, the band pass filter 163, and the A / D converter 164. The generated tomographic image is displayed on the image display unit 166.

  In the present embodiment, by introducing the balance detection method in this way, it is possible to remove the bias component (including the fluctuation of the light source) in the interference wave, and it is possible to extract only the interference wave component. That is, the characteristic part in this embodiment is expressed as shown in FIG. 4, and the signal light and the reference light are demultiplexed into the signal light and the reference light having the intensity distribution as shown by the optical couplers 261 and 271, respectively.

  The intensity distribution of the interference signal A obtained by the first multi-channel detector 252A and the intensity distribution of the interference signal B obtained by the second multi-channel detector 252B are expressed by the following equations (4) and ( 5). In the following expression, Es represents the light intensity of the signal light, Er represents the light intensity of the reference light, ω represents the frequency of the light wave, and * represents an imaginary number.

  Therefore, the interference signal output from the difference calculator 282 is expressed by the following equation (6).

  From the above equation (6), it is clear that in the interference signal, the bias component is canceled and only the interference signal component is doubled.

  In the embodiment of the present invention, similarly to the reference example of FIGS. 1 and 2, an optical scanning unit for scanning illumination light in a predetermined direction along the surface of the subject 231 is provided, and the scanning is performed. The light intensity distribution in the depth direction of each point obtained according to the above is obtained, and the image processing unit 165 performs image signal processing that connects the light intensity distribution in the depth direction of each point to perform a two-dimensional tomographic image signal. Is generated.

  In the Young's interferometer according to the embodiment of the present invention, by arranging a lens similar to the objective lens 151 which is a feature of the reference example of FIG. 2, the effect of the reference example of FIG. be able to.

  Also in this embodiment of the present invention, similarly to the reference example of FIGS. 1 and 2, the reference mirror 242 is configured to be movable in the optical axis direction, and the detection range in the depth direction of the subject 231 is configured. It is also possible to change the sampling pitch at the time of detection by changing each of the multi-channel detectors 252A and 252B so as to be movable in the optical axis direction.

  Similarly to the reference example of FIGS. 1 and 2 described above, an objective condensing lens provided at the tip of the light guide member 233 for condensing and irradiating the subject 231 with illumination light can be moved in the optical axis direction. You may make it prevent defocusing of the subject image in an observation position.

  The tomographic image apparatus of the present invention can be modified in other forms. For example, a low coherence light source such as a normal diode or a high-pressure mercury lamp can be used instead of the above-described light source. Can be used.

  The multi-channel detector of the above embodiment is assumed to be one-dimensional. However, the multi-pixel image sensor in the tomographic image apparatus of the present invention is not limited to this, and for example, two-dimensional light detection is performed. The surface sensor to perform may be sufficient. For example, Optics Japan 2003 Proceedings pp.102-103 “Non-Scanning OCT Measurement Using Angular Dispersion Imaging” (Umetsu, Akiba, Chen, Tanno) etc. .

  In the above embodiment, the Michelson type is used as the equal optical path length type interferometer, but other equal optical path length type interferometers such as the Mach-Zehnder type are used instead. Also good.

  The subject is not limited to the human body, and may be various other tissues in which light enters the inside and the reflected light is obtained from each position inside.

111, 211, 310 Low coherence light sources 121, 122, 123, 124, 126, 127, 221, 222, 223, 224, 226, 227, 262, 263, 272, 273, 321, 322, 323, 324
Optical fibers 125, 225, 261, 271, 325 Optical couplers 126A, 127A, 262A, 263A, 272A, 273A Outgoing ends 131, 231, 331 Subjects 132, 143, 232, 243 Optical circulators 133, 233 Light guide member 141, 241 and 341 Collimator lenses 142, 242 and 342 Reference mirror 151 Objective lenses 152, 252A and 252B Multichannel detectors 162 and 362 Amplifiers 163 and 363 Bandpass filters 164 and 364 A / D converter 165 Image processing units 166 and 366 Image display 282 Difference calculator 332 Objective condenser lens 352 Photodetector

Claims (8)

A light source that emits light having low coherence;
A light irradiation optical system configured to divide the light emitted from the light source into two parts, irradiate one of the objects to the subject and irradiate the other to the reference mirror;
The signal light from the subject based on the light irradiation from the light irradiation optical system is demultiplexed, and the second signal light causes a predetermined phase shift with respect to the demultiplexed first signal light. A first light guide member that guides each to different light exit ends;
The reference light from the reference mirror based on the light irradiation is demultiplexed, and the second reference light causes a predetermined phase shift with respect to the demultiplexed first reference light, so that each light is different from each other. A second light guide member leading to the exit end;
Light of interference light caused by the first signal light emitted from the light emission end of the first light guide member and the first reference light emitted from the light emission end of the second light guide member A first multi-pixel imaging device for obtaining an intensity distribution signal;
Light of interference light caused by the second signal light emitted from the light emission end of the first light guide member and the second reference light emitted from the light emission end of the second light guide member A second multi-pixel imaging device for obtaining an intensity distribution signal;
A light intensity distribution difference means for obtaining a difference between the light intensity distribution signal obtained by the first multi-pixel image sensor and the light intensity distribution signal obtained by the second multi-pixel image sensor;
A tomographic image apparatus comprising:   Each emission end of the first light guide member and the second light guide member functions as a point light source, the emission end corresponding to the first multi-pixel image sensor, and the first multi-pixel image sensor And the positional relationship between the emission end corresponding to the second multi-pixel image sensor and the second multi-pixel image sensor are arranged so as to constitute Young's interferometer, respectively. The tomographic imaging apparatus according to claim 1.   The tomographic imaging apparatus according to claim 1, wherein the first light guide member and the second light guide member are made of optical fibers.   An objective lens is inserted between each emission end of the first light guide member and the second light guide member and the multi-pixel image sensor, and the objective lens is placed on the multi-pixel image sensor, 4. The tomography according to claim 1, wherein the position is set so that an overlapping region between the corresponding signal light and the reference light from each of the emission ends becomes large. Video equipment.   5. The tomographic image apparatus according to claim 1, further comprising an optical scanning unit configured to scan light from the light source in a predetermined direction along the surface of the subject.   The tomographic imaging apparatus according to claim 1, wherein the reference mirror is movable in an optical axis direction of the reference mirror.   The tomographic image apparatus according to claim 1, wherein the multi-pixel image sensor is movable in an optical axis direction of the multi-pixel image sensor. Tomographic image information calculating means for analyzing and calculating tomographic image information of the subject based on an output signal from the multi-pixel imaging device and scanning timing of the optical scanning means, and tomographic image information obtained by the tomographic image information calculating means The tomographic image apparatus according to any one of claims 5 to 7, further comprising a tomographic image display means for displaying

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