JP2001289781A - Light wave vertical cross section tomography observation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light wave vertical cross section tomography observation apparatus enabling observation of an internal three-dimensional solid image of an object in an actual time over a wide dynamic range. SOLUTION: In this light wave vertical cross section tomography observation apparatus, a two-dimensional lock-in image intensifier is provided, so that a multiplication image can be observed. The two-dimensional lock-in intensifier is provided with a photocathode 2 for converting incident image light into photoelectron flow modulated two-dimensional spatially by square-law detection, a microchannel plate 6 provided with a front face part having a multiplication secondary electron producing function, based on secondary electron emission of the photoelectron flow and a back electrode in a back face part, and a fluorescent screen 7, having concurrently a fluorescent conversion action of the two-dimensional multiplication secondary electron flow based on the multiplication secondary electron producing function and an action superimposing and accumulating electrons in a fixed cycle on an excited fluorescent level in a fluorescent medium, when the secondary electron flow is an alternating current.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a two-beam interference image of an object light from a light-reflecting or light-transmitting object and a reference light, and an image intensifier that has performed a two-dimensional lock-in operation. By extracting only the AC component and performing two-dimensional lock-in detection, the DC component and the low-frequency component including the background noise light are removed, and the two-dimensional lock-in image is simultaneously amplified. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light wave vertical cross-section tomography observation apparatus capable of easily observing a tomographic image of a living body.

[0002]

2. Description of the Related Art An attempt to obtain a vertical tomographic image of a living body, which is a high light scattering medium, is carried out by detecting a reflected or transmitted signal by scanning one light beam as one pixel signal, detecting the signal by heterodyne detection and a lock-in amplifier, and performing numerical calculation CT (C
(Omputer Tomography). This new method is described in detail, for example, in Naohiro Tanno, [Optics, Vol. 28, No. 3, 116 (1999)].

[0003]

However, in the above-described conventional method, scanning for obtaining all pixel signals and arithmetic processing of those signals require time, real-time observation is impossible, and an arbitrary cross section cannot be obtained. Extraction and visualization require a huge amount of scanning and computation processing time, and no technique has yet been attempted for holographically stereoscopically viewing the deep part of a living body.

The present invention has been made to solve the above problems.
It is an object of the present invention to provide a light wave vertical cross-section tomography observation apparatus capable of observing a three-dimensional internal image of these objects in a wide dynamic range in real time.

[0005]

In order to achieve the above object, the present invention provides a photocathode for converting incident image light into a photoelectron stream which is two-dimensionally spatially modulated by square detection, and comprising: A microchannel plate with front and rear electrodes having a function of generating a secondary electron by electron emission, and a fluorescent conversion of a two-dimensional multiplied secondary electron flow by the function of generating a secondary electron. When the secondary electron flow is alternating current, a two-dimensional lock-in image intensifier equipped with a phosphor screen that also serves to superimpose and accumulate electrons for a certain period on the excited fluorescence level in the fluorescent medium is provided. A multiplied image can be observed. For example, when incident image light is two-dimensional image light of two-beam interference and heterodyne detection is performed on the photocathode, the distribution of photoelectron current generated from the photocathode is distributed to each pixel. And the photocathode and the micro-electrode so as to change temporally in synchronization with the frequency of the amplitude modulation when comprising a DC component photoelectron stream and a video signal AC component photoelectron stream that has been subjected to amplitude modulation based on the heterodyne detection. Means for applying an AC voltage equal to the frequency of the amplitude modulation between the electrodes on the front face of the channel plate, and a two-dimensional electron density cross-sectional distribution according to the image on the front face of the micro channel plate with the electrodes on the front face of the micro channel plate. Means for applying a constant voltage between the electrodes on the rear surface of the microchannel plate to perform two-dimensional electron multiplication, and applying a constant voltage between the electrodes on the rear surface of the microchannel plate and the electrodes on the phosphor screen to cause the front surface of the microchannel plate to -Dimensional fluorescence intensity cross-section distribution similar to the two-dimensional electron density cross-section distribution according to the image of Means for performing two-dimensional lock-in amplification in accordance with the integration operation of a narrow band filter for superimposing and accumulating excitation electrons for a certain period of the frequency of the amplitude modulation of the two-dimensional fluorescence intensity cross-sectional distribution on the fluorescent medium. A DC component including a background noise light and a low frequency component of the incident photoelectron stream subjected to the amplitude modulation, and a high frequency video signal subjected to amplitude modulation based on heterodyne detection. Is superimposed and accumulated in a fluorescent medium so that it can be observed.Furthermore, a diverging irradiation group is formed by a multi-lens array to obtain multiple in-line holograms on the photocathode, and a tomographic image of the measured object is obtained. It is a light wave vertical cross-section tomography observation device that can be stereoscopically viewed in real time or computer numerical operation method without special operation. You.

In such a configuration, one of the two-beam interference light, which is incident image light, is reflected or transmitted light from a highly scattering medium or the like, and the other light is phase-shifted or relative to the other light. Frequency shift to the reference light and none,
Heterodyne detection is performed by multiplex interference between the two, and the detected photoelectron current is a DC component due to scattered light or two light beams and an AC component due to a reflected image signal light of a tomographic image or a perspective image signal light (amplitude modulation frequency is a phase shift modulation frequency Or it is determined by the difference frequency of the relative frequency shift). After the application of an acceleration electric field synchronized with the frequency and the secondary electron emission by photoelectrons, the multi-channel plate multiplies by two-dimensional electron multiplication. The multiplied two-dimensional electron density cross-sectional distribution is converted into a two-dimensional fluorescence intensity cross-sectional distribution, and two-dimensional lock-in detection for synchronizing with the amplitude modulation frequency and superimposing and accumulating excitation electrons for a certain period on the fluorescent medium is performed for the entire screen. By executing a high-pass filter operation, only a two-dimensional fluorescence intensity cross-sectional distribution image according to the high-frequency AC component image intensity distribution is obtained on the fluorescent screen to reduce background noise light. It is obtained so as to be easily observed by extracting to remove a DC component and low frequency component reflected tomographic image or fluoroscopic image I.

Further, the object to be measured is irradiated with multiple divergent light by using a multi-lens array among the two light beam interference lights,
The reflected light or transmitted light is used as the object light and caused to interfere with the reference light. In this case, the two-beam interference image light becomes a multiplexed in-line hologram, but in the same manner as described above, the direct current including the background noise light is used. Obtain a fluorescence image by extracting multiple in-line holograms of reflection tomographic images and perspective images from which components and low-frequency components have been removed, and read out the multiple in-line holograms as coherent images using a known incoherent / coherent image converter. Reproduced, using an imaging device with a known zoom lens, it is possible to immediately observe any reflection tomographic image or fluoroscopic image of the deep part of the object with the focal position of the lens of this imaging device, furthermore, the incoherent・ Multiple in-line holograms can be photographed with an ordinary imaging tube without using a coherent image converter, And numeric input to the machine is to reconstruct an image of an arbitrary cross section using computer reconstruction algorithm of the hologram.

[0008]

Embodiments of the present invention will be described below in detail. FIG. 1 is a configuration diagram of a two-dimensional lock-in image intensifier composed of a proximity type or a vacuum tube type showing an embodiment of the present invention, and FIG. 1 (a) shows the whole of the two-dimensional lock-in image intensifier. FIG. 1B is an enlarged view of a portion A in FIG. 1A.
FIG. 2 is an explanatory diagram of the incident light intensity of the two-dimensional lock-in image intensifier shown in FIG. 1 and the voltage applied to the photocathode. FIG. 2A includes a video signal AC component that generates a photoelectron flow 3. FIG. 2B is a time waveform diagram of the incident light, and FIG. 2B is an applied voltage waveform Va for a lock-in operation for removing a DC component and sending only an AC component to the microchannel plate 6.

Here, reference numeral 100 denotes a two-dimensional lock-in image intensifier, which transmits the incident image light 1 to the window 9 of the two-dimensional lock-in image intensifier 90.
Irradiates the photocathode 2 from 0a to generate a photoelectron flow 3,
Between the photocathode 2 and the front surface electrode 6a as shown in FIG.
The voltage Va from the control voltage oscillator 4 is applied so as to change temporally in synchronization with the frequency of the amplitude modulation of the incident light, and only the AC component is synchronously detected. Collide.

The photoelectron flow 3 generated in synchronization with the frequency of the amplitude modulation is incident on the front surface of the micro channel plate. The micro channel plate 6
As shown in FIG. 1 (b), it is very thin, for example, having a diameter of 12 mm.
It is configured by bundling many glass pipes of about μm. The reason that the glass pipe is inclined with respect to the incident axis of photoelectrons is that
This is because the secondary electron emission is efficiently generated on the inner wall of the pipe, and is a well-known technique. The incident photoelectron flow 3 hits the inner wall of the pipe near the end face of the glass pipe, and emits secondary electrons. By applying a constant DC voltage Vb between the front electrode 6a and the rear electrode 6b of the microchannel plate 6, the two-dimensional secondary electron flow of only the video signal AC component reflecting the two-dimensional electron density cross-sectional distribution is accelerated. The multiplied secondary electron flow 8 is generated.

The two-dimensional electron density cross section distribution multiplied secondary electron flow is applied to the rear surface electrode 6 b of the microchannel plate 6.
Then, the two-dimensional fluorescent image is formed on the fluorescent screen 7 accelerated by the fluorescent screen acceleration voltage Vs shown in FIG. 2 above
The two-dimensional fluorescent image is superimposed and accumulated on the fluorescent screen 7 for a certain period in synchronization with the frequency of the amplitude modulation, and performs two-dimensional lock-in amplification in accordance with the integration operation of the narrow band filter, thereby generating the photoelectrons generated by the incident image light. The DC component and the low-frequency component including the background noise light component of the stream are removed, and for example, only the high-frequency AC component of the heterodyne beat signal becomes a video signal that is amplified and emphasized. On the other hand, since the phosphor material applied to the phosphor screen has a relatively long fluorescence lifetime of about 100 msec, an interference light image can be observed in the range of the fluorescence lifetime, and after the fluorescence lifetime, The original image disappears, but if a gate pulse voltage such as a sine wave or a triangular wave shown in FIG. 2 is applied, a clear still image for one screen can be observed by a general imaging device such as an NTSC system. As a matter of course, it can be directly observed from the window 90b. For example, when the fluorescence lifetime is set to 100 msec, the AC component frequency is set to 100 kHz, the integration of 7000 cycles, and 30 ms
Video reading for ec / 1 frame becomes possible. At this time, the signal component accumulated by this integration with respect to the video signal observed only in one cycle is amplified by 7,000 times. In this setting example, 10 screens can be observed per second, which is one third of the video signal rate.
Near real-time observation will be possible. Further, as shown in FIG. 2, if a gate pulse voltage such as a sine wave or a triangular wave is continuously applied, a deep image of a stationary object can be continuously observed during that time. FIG. 3 is a configuration diagram of a basic light wave vertical cross-section tomography observation apparatus for observing a reflected tomographic image according to the first embodiment of the present invention.

As shown in FIG. 3, a low coherent light source 1
0, for example, center wavelength 0.85 μm, spectrum width 3
0 nm super luminescent diode (SLD)
And the output light is converted into a parallel light beam 18a having an effective cross-sectional diameter by using the beam expander 11. This parallel light beam 18a is split by the beam splitter 13 into two light beams. Of the divided light beams, the straight transmitted light is reflected by the reflecting mirror 1.
4 to form the reference beam 18b. Reference light 1
8 b is reflected by the beam splitter 13 and reaches the photocathode 2. The reflecting mirror 14 is a transducer 14
a (for example, a piezoelectric actuator) by applying a voltage synchronized with the sine wave or the triangular wave, for example, to oscillate at the frequency of 100 kHz, thereby causing the reference light 18b to have a phase-modulated reference light electric field E _ra represented by the following equation. (T, z).

[0013] _{E ra (t, z) =} E ra exp _{[j2πft-j2kL r -j2kδ z sin (} 2πf a t) ] (1) where, E _ra reflected light field amplitude, f is the optical frequency, k Is the wave number, L _r is the optical path length from the beam splitter 13 to the reflecting mirror 14, δ _z is the displacement distance of vibration, f _a is the vibration frequency,
j is an imaginary unit. The third term in parentheses on the right exponent of the above equation (1) represents a phase modulation that oscillates sinusoidally. The reference light electric field represented by the above equation (1) is a plane wave electric field that irradiates the photocathode 2 with uniform intensity.

The other reflected light beam split on the other side enters the measured object 12. This incident light is reflected on each tomographic plane due to a change in the refractive index in the measured object 12, and projects an image of the tomographic plane AA ′ in the measured object 12 on the photoelectric surface 2. At the same time, the photocathode 2 is illuminated as a distorted wavefront that does not image reflected light from before and after the tomographic plane AA '. The electric field of the reflected signal light from the tomographic plane AA ′ to be observed is E _sa (x, y), and the electric field of the disturbed wavefront is the noise electric field E _na (x, y). _oa (t, r) can be expressed by the following equation.

[0015] _{E oa (t, r) =} E sa (x, y) exp [j2πft-j2kL _{s] + Σ n E na (x,} y) exp [j2πft-j2kL _s -j2knΔz] ... (2) where, (X, y) represents the position of the image plane, and r is x, y,
Let z be representative, and L _s is the optical distance between the tomographic plane AA ′ and the beam splitter 13. Σ _n is the fault plane A
Represents the sum of the noise fields, including multiple reflections from planes other than -A ', n △ z represents the distance from L _s to each of these planes, and △ z represents the optical distance resolution. .

The phase-modulated reference light electric field E _ra (t, z) and the object light electric field E _oa (t, r) form incident image light 1 of two-beam interference on the photocathode 2. The incident image light 1 includes the noise component and the DC component other than the video signal to be observed, and it is generally impossible to extract only the cross-sectional image to be directly observed and viewed. The incident image light 1 is square-detected by the photocathode 2 and converted into a photoelectron stream 3 represented by the following equation _Ia (t, r).

[0017] _{I a (t, r) =} Q | E ra (t, z) + E oa (t, r) | 2 = Q {E ra 2 + [E _sa (x, y)] ² + ^Σ _n ^Σ _{m E na (x, y) E} ma * (x, y) exp [-j2k (n-m) △ z] + c. _{c + E ra E sa (x} , y) J 0 (2kδ z) cos [2k (L _r -L _{s)] + E ra E sa (x,} y) J 1 (2kδ z) cos _{[2πf a t + 2k (L r} - L _{s)] + Σ n E ra E na (} x, y) J 0 (2kδ z) cos _{[2k (L r -L s -n △} z) ] _{+ Σ n E ra E na (} x, y) J 1 ( 2kδ _z) cos _{[2πf a t + 2k (L r} -L s -n △ z) ]} (3) where, Q is the conversion coefficient, including quantum efficiency of converting light intensity into photoelectrons, of each of the field The amplitude is a real number, the sine function in the exponential function is expanded by the Bessel function,
Up to the next term, higher-order terms were ignored because they were not observed. J ₀
(2kδ _z ) and J ₁ (2kδ _z ) are 0 order and 1 order, respectively.
Here is the Bessel function.

The low coherent light source 10 has a wide spectral width and a distance at which two-beam interference can occur, that is, a coherence length _Lc is as short as several tens μm or less. With attention to the reflection from the surface of the equal distances L _s to the optical distance L _r, the optical path difference between the two is zero. Furthermore, Kohi - since the reflected light each other from the plane of the optical path difference than Reference length L _c do not interfere, can put a spatial distance resolution △ z = L _c / 2, in the formula (3), 2 △ There will be no product terms of different electric fields including z. Therefore, the terms actually generated as the photoelectron flow 3 are as follows.

I _a (t, r) = Q ｛E _ra ² + [E _sa (x, y)] ² + Σ _n [E _na (x, y)] ² + 2E _ra E _sa (x, y) J _{0 (2kδ z) + 2E ra E} sa (x, y) J 1 (2kδ z) cos (2πf a t)} ... (4) in this equation (4), fourth term until the background noise light from the first term And the fifth term is _a video signal AC component photoelectron stream whose amplitude is modulated at the frequency fa and which is to be observed. The photoelectron stream 3 as described in the two-dimensional lock-in image intensifier 90 of the embodiment, is the lock-in integration with the frequency f _a. The frequency f _a is then generated by the oscillator 15,
The transducer 14a is driven and the other terminal 5
The AC applied voltage Va represented by the following equation is generated in synchronization with the control voltage oscillator 4 for the time T. _{Va = V d cos (2πf a} t) ... (5) where, V _d represents the applied voltage value. An electric field expressed by the following equation is formed between the photocathode 2 and the front electrode 6a of the microchannel plate 6 by Va expressed by the equation (5), and the flow of the photoelectron flow 3 is controlled. _{Va / d = V d cos (} 2πf a t) / d ... (6) where, d photocathode 2 and the microchannel plate 6
Is the distance between the front electrodes 6a. Due to the electric field of the expression (6), the photoelectron flow 3 becomes a flow represented by the following expression. _{I m (t, r) =} (Va / d) Q 1 I a (t, r) = {V d cos (2πf a t) / d} QQ 1 {E ra 2 + [E _sa (x, y) ] ² + sigma _n [E _na (x, y)] ^{_{2 + 2E ra E sa (x}} , y) J 0 (2kδ z) + 2E ra E sa (x, y) J 1 (2kδ z) cos (2πf a t) _{} = (V d / d)} QQ 1 {E ra 2 cos (2πf a t) + [E _sa (x, y)] _{^{2 cos (2πf a t) +}} Σ n [E _na (x, y)] ² cos _{(2πf a t) + 2E ra} E sa (x, y) J 0 (2kδ z) cos (2πf a t) + E ra E sa (x, y) J 1 (2kδ z) + E ra E sa (x, y) J ₁ (2kδ _z ) cos [2π (2f _a ) t] ７ (7) Here, Q ₁ is a conversion coefficient until the light enters the microchannel plate 6. By the lock-in operation, a high-pass filter action is performed, and as a result, the DC component and the low-frequency component including the background noise light up to the first to fifth terms on the right side of the third equation of the above equation (7) are removed. , ((V _d / d) QQ ₁ E _ra E _sa (x,
Only photocurrent represented by _{y) J 1 (2kδ z)} cos [2π (2f _a) t] "flows to the front portion 6a of the microchannel plate 6, the photoelectron flow is represented by the following formula. I _m ( _{t, r) = (V d} / d) QQ 1 E ra E sa (x, y) J 1 (2kδ z) cos [2 [pi (2f _a) t] ... (8)

The optical shutter 16 is connected to its driving circuit 16
At a, the shutter 16 is opened by applying a gate pulse voltage for T time corresponding to the fluorescence lifetime, and an image according to the image signal is generated on the fluorescent screen 7 and the inside of the measured object 12 including the reference light component is included. The tomographic image “E _ra ” of the tomographic plane AA ′
E _sa (x, y) "only is observed is amplified emphasized. Included in the right side of the equation _{(8)" E ra E sa} (x, y) J 1
(2kδ _z ) "varies depending on the value of the Bessel function, but gives one maximum value of the Bessel function, for example, 2
δ _z = 0.45λ / π, where kδ _z = 1.8 (where λ _z
By setting a vibration displacement of (wavelength of light), an image can be observed efficiently.

The image observed on the fluorescent screen 7 is expressed by the following equation, where G is the product of the gain coefficient of the microchannel plate 6 and the conversion coefficient on the fluorescent screen. _{I 1 (t, r) =} GI m (t, r) = G (V d / d) QQ 1 E ra E sa (x, y) J 1 (2kδ z) cos [2π (2f _a) t] ... (9) In addition to the 7,000-fold multiplication by the above-mentioned integration, when the multiplication of 1.2 × 10 ⁴ is achieved by one MCP image intensifier, The total gain of the multiplication is about 79.2 dB, and 3 ×
When multiplying by 10 ⁶ , an overall gain of about 103.2 dB is obtained. A sufficient gain for observing a tomographic image in a highly scattering medium such as a living body can be obtained.

When observing another part by changing the position of the internal tomographic plane AA 'of the measured object 12, the stage 12a on which the measured object 12 shown in the embodiment of FIG. It is realized by moving to. Alternatively, the same effect can be obtained by moving the reflecting mirror 14 in the optical axis direction. If the moving distance is taken for each spatial distance resolution △ z, the depth z
Observation with the minimum resolution in the axial direction is realized, and the resolution in the xy plane is determined by the resolution of the phosphor screen 7 more than the aperture of the lens and is observed.

When a commercially available SLD or a broadband fluorescent light source is used for the low coherent light source 10, the minimum depth resolution Δz is 1
On the other hand, the existing fluorescent screen 7 can realize a resolution of about 30 μmφ on the two-dimensional plane.

The light reflection image formed on the fluorescent screen 7 is converted into an image signal by the imaging device 30 and further converted to an image signal by the image processing device 3.
In step 1, the image is clarified and a three-dimensional stereoscopic image is constructed, and is displayed on the display device 32. In FIG. 3, 18
c is the reflected object light.

FIG. 4 is a configuration diagram of a light wave vertical section tomography observation apparatus for observing a reflected tomographic image according to a second embodiment of the present invention. As shown in this figure, a low-coherence light source 10 is provided with, for example, a superluminescent diode (SL) having a center wavelength of 0.85 μm and a spectrum width of 30 nm.
Using D), the emitted light is converted into a parallel light beam 18a having an effective cross-sectional diameter using the beam expander 11. The parallel light beam 18a is converged by using the lens 17a, and is split into two light beams by the beam splitter 13. Of the divided light beams, the straight transmitted light is returned to the original parallel light beam 18a by the lens 17b and further reflected by the reflecting mirror 14 to form the reference light 18b. The reference beam 18b is
After passing through 7b, the light is further reflected by the beam splitter 13 and becomes a parallel light beam again by the lens 17d to reach the photoelectric surface 2. The reflecting mirror 14 is a transducer 14a
By applying a voltage synchronized with the sine wave or the triangular wave or the like to the
By vibrating at 0 kHz, the reference light 18b is converted into a phase-modulated reference light electric field E _rp (t, z) represented by the following equation. _{E rp (t, z) =} E rp exp _{[j2πft-j2kL r -j2ksin (2πf a} t) ] ... (10) the reference optical field of the formula (10) is uniform intensity photoelectric surface 2 Irradiates a plane wave electric field.

The other reflected light beam split by the other is returned to a parallel light beam by the lens 17c and enters the measured object 12. This incident light is reflected on each tomographic plane due to a change in the refractive index within the measured object 12, but the reflected object light 18c at the front focal position AA 'of the lens 17c is rearwardly illuminated by the lens Fourier transform action of the lens 17c. The lens 17d having the same focal length as that of the lens 17c is Fourier-transformed to the focal position, and the lens 17d is disposed at the position of the inverse Fourier transform function, and the image of the tomographic plane A-A 'is projected on the photoelectric surface 2. At the same time, the photocathode 2 is illuminated as a distorted wavefront that does not image reflected light from before and after the tomographic plane AA '. The electric field of the reflected signal light from the tomographic plane AA ′ to be observed is E _sp (x, y), the electric field of the disturbed wavefront is the noise electric field _Enp (x, y), and the electric field of the object light from the measured object 12 is E _op (t, r) can be expressed by the following equation. _{E op (t, r) =} E sp (x, y) exp [j2πft-2jkL _{s] + Σ n E np (x,} y) exp [j2πft-2jkL _s -2jknΔz] ... (11)

The phase-modulated reference light electric field E _rp (t, z) and the object light electric field E _op (t, r) form incident image light 1 of two-beam interference on the photocathode 2. The incident image light 1 includes the noise component and the DC component other than the video signal to be observed, and it is generally impossible to extract only the cross-sectional image to be directly observed and viewed. The incident image light 1 is square-detected by the photocathode 2 and converted into a photoelectron stream 3 represented by the following equation. _{I b (t, r) =} Q | E rp (t, z) + E op (t, r) | 2 = Q {E rp 2 + [E _sp (x, y)] ^{_{2 + Σ n Σ m E np}} ( ^{_{x, y) E mp * (}} x, y) exp [-2jk (n-m) △ z] + c. _{c + E rp E sp (x} , y) J 0 (2kδz) cos [2k (L _r -L _{s)] + E rp E sp (x,} y) J 1 (2kδz) cos _{[2πf a t + 2k (L r} -L _{s)] + Σ n E rp E np (} x, y) J 0 (2kδz) cos _{[2k (L r -L s -n △} z) ] _{+ Σ n E rp E np (} x, y) J 1 (2kδz) cos _{[2πf a t + 2k (L r} -L s -n △ z) ]} (12)

The low coherent light source 10 has a wide spectral width and a distance at which two-beam interference can occur, that is, a coherence length _Lc is as short as several tens μm or less. With attention to the reflection from the surface of the equal distances L _s to the optical distance L _r, the optical path difference between the two is zero. Furthermore, since the reflected light each other from the plane of the optical path difference than the coherence length L _c do not interfere, and put the spatial distance resolution △ z = L _c / 2, in the above formula (12), including different 2 △ z There will be no product term for the electric field. Therefore, the terms actually generated as the photoelectron flow 3 are as follows. I _b (t, r) = Q ｛E _rp ² + [E _sp (x, y)] ² + Σ _n [E _np (x, y)] ² + 2E _rp E _sp (x, y) J ₀ (2kδz) _{+ 2E rp E sp (x,} y) J 1 (2kδz) cos (2πf a t)} ... (13)

In equation (13), from the first term on the right side
DC component photoelectrics including those due to background noise light up to the fourth term
The fifth term is the frequency f_aObserved with amplitude modulation
It is a video signal AC component photoelectron flow to be obtained. This photocurrent
3 is as described in the first embodiment shown in FIG.
The same control as in the first embodiment is performed at this frequency f
_aHigh-pass filter
The DC component includes background noise light.
And the low frequency component is removed, and the high frequency component "(V_d
/ D) QQ₁E_rpE_sp(X, y) J₁(2kδ_z) Co
s [2π (2f _a) T] ”is the only photocurrent
It flows to the front electrode 6 a of the channel plate 6.
The video signal AC component photoelectron current is applied to the fluorescent screen 7 in FIG.
Until it is visualized, it is completely different from the first embodiment shown in FIG.
Since they are the same, the description of those parts is omitted. FIG.
Light wave vertical section with optical fiber scope showing a third embodiment
It is a block diagram of a tomography observation apparatus.

This embodiment is a remote observation device in which an optical fiber scope 28 is provided on the optical path from the lens 17c to the object in the second embodiment shown in FIG. As shown in FIG. 5, the parallel light beam from the lens 17c is made incident on the end face 28c of the optical fiber scope 28. This parallel light beam is emitted from the other end surface 28b, and irradiates the measured object 12 with the lens 28a. The reflected object light 18c from the irradiation tomographic plane AA 'inside the measured object 12 is imaged on the end face 28b by the action of the lens 28a. The imaging light is transmitted through the optical fiber scope 28 and appears on the end face 28c. By setting the position of the end face 28c at the position of the front focal point of the lens 17c,
An irradiation tomographic plane AA ′ is projected on the photocathode 2 by the lens Fourier transform of c and the lens Fourier inverse transform of the lens 17d. At this time, it is natural that the irradiated tomographic plane A-
The reflected light before and after A 'is included as background noise light.

From the beam splitter 13 to the irradiated tomographic plane A
Optical path length L _r of the optical path length L _s of up -A 'to the reflecting mirror 14
Need to be set to the same distance, the latter optical path may be configured by propagation in air or a folded prism, but an optical fiber scope of the same length may be provided. Other operation methods of the light wave vertical section tomography observation apparatus are the same as those described in the embodiment of FIG. FIG. 6 is a configuration diagram of a light wave vertical section tomography observation apparatus for observing a reflected tomographic image according to a fourth embodiment of the present invention.

As shown in FIG. 6, the high coherent light source 1
For example, a laser oscillator having a high biotransmittance and a wavelength of 1.3 μm is provided in Oa, and the emitted light beam is split into two by a beam splitter 13a. One of the two split light beams is transmitted through the frequency shifter 22a using, for example, a photoacoustic element, frequency-shifted, converted into a parallel light beam having an effective diameter using the beam expander 11a, and reflected by the return reflecting mirror 19a. The reference light is assumed to be 20a. At this time, the reference light electric field E _rb
(T, r) is expressed by the following equation.

E _rb (t) = E _rb exp [j2π (f−f _a ) t] (14) where E _rb represents an electric field amplitude of light having a uniform beam cross-sectional intensity, and f _a represents _a shift. Represents frequency. In the above equation (14), the photoelectric surface 2 where the two light beams interfere is taken as the origin, and the phase term of the propagation distance is excluded. The other split parallel beam is
The frequency shifter 22b is transmitted using, for example, a photoacoustic element, subjected to a frequency shift f _b , converted into a parallel light beam having an effective diameter using the beam expander 11b, reflected by the return reflecting mirror 19b, and reflected from the object 12 to be measured. Irradiate. The divergent irradiation light group 20b propagates inside the object and is reflected on each tomographic plane inside the object. The reflected light group is reflected by the half mirror 13b, is combined with the reference light 20a, and becomes the incident image light 1. This reflected light group can be expressed by the following equation. _{E sb (t, r) =} E sb (x, y) exp [j2π (f-f _b) t] _{+ Σ n E n exp (j2πft} ) ... (15) the first term on the right side of the equation (15), The second term represents background noise light based on multiple reflections or the like, and represents the reflected object light holding the electric field E _sb (x, y) having information on the reflected tomographic image plane.

The incident image light 1 causes two-beam interference on the photoelectric surface 2. A heterodyne interference image is formed on the photocathode 2 due to interference between the reflected object light and the parallel light reference light. The resulting photoelectron flow is: I _c (t, r) = Q | E _rb (t) + E _sb (t, r) | ² = Q ｛E _rb ² + [E _sb (x, y)] ² + Σ _n | E _n | ² + Σ _{n E n E rb cos (2πf a} t) + E rb E sb (x, y) cos (2πf c t)} ... (16) the third term from the second equation of the first term on the right side of the equation (16) Represents the DC component photoelectron flow including background noise light, and
The fourth term is a high-frequency component that does not respond in time in the two-dimensional lock-in image intensifier 90, and is averaged due to interference by multiple scattered light to become a DC component. Beat frequency fifth term is due to heterodyne detection f _c = | f
_a −f _b | represents a video signal alternating-current component photoelectron flow to be observed, which is amplitude-modulated.

[0035] The photoelectron stream 3 is locked in integrating the frequency f _c as described in the two-dimensional lock-in image intensifier 90 of the embodiment. As a result, in the above equation (16), although the frequency is different, FIG.
The same control as in the first embodiment is performed, and a photoelectron flow expressed by the following equation flows. _{I t (t, r) =} (Va / d) Q 1 I c (t, r) = {V d cos (2πf c t) / d} QQ 1 {E rb 2 + [E _sb (x, y) ] ^{_{2 + Σ n | E n |}} 2 + Σ n E n E rb cos (2πf a t) + E rb E sb (x, y) cos (2πf c t)} = (V d / d) QQ 1 {E rb 2 cos (2πf _c t) + [E _sb (x, y)] _{^{2 cos (2πf c t) +}} Σ n | E n | 2 cos (2πf c t) + (1/2) E rb E sb (x, y _{) + (1/2) Σ n E} n E rb [cos _{[2π (f c + f a)} t ] + cos [2π (f _c -f _{a) t]] + (1/2) E rb E} sb (x , y) cos [2 [pi (2f _c) t]} (17) where, Q ₁ is a conversion coefficient to entering the microchannel plate 6. The first to fourth terms on the right side of the third equation of the above equation (17) represent the photocurrent of the DC component and the low-frequency component including the background noise light, and the fifth term is:
In the two-dimensional lock-in image intensifier 90, a high-frequency component that does not respond in time and is averaged due to interference by multiple scattered light to become a DC component. The beat frequency Item 6 is by heterodyne detection _{f c = | f a -f b} |
Represents an alternating-current component photoelectron flow of a video signal to be amplitude-modulated and desired to be observed. The frequency f _c is the frequency shifter 22a 22
The signal AC is generated from the difference frequency oscillator 15a, and the AC applied voltage Va is synchronously generated from the terminal 5 via the control voltage oscillator for the time T.

By the high-pass filter effect by the lock-in operation, the first right side of the third equation of the above equation (17) is obtained.
The DC component and the low-frequency component including the background noise light from the term to the fifth term are removed, and only the photoelectron current shown in the sixth term flows to the front surface 6a of the microchannel plate 6, and is expressed by the following equation. . _{I t (t, r) =} (V d / d) QQ 1 (1/2) E rb E sb (x, y) cos [2 [pi (2f _c) t] (18) applies a gate pulse of T time Terminal 9 at the same time
By transmitting the voltage more, an image of an in-line hologram according to the interference image is formed in a portion corresponding to the position of one lens.

As a result, a light reflection image “E _rb E _sb (x,
y) "is observed on the phosphor screen 7 as a clear image from which the DC component and the low-frequency component including the background noise light have been removed. I ₂ (t, r) = G (V _d / d) QQ _{1 (1/2) E rb E sb} (x, y) cos [2 [pi (2f _c) t] (19) further, in order to clear reflected image is the embodiment of FIG. 8 with respect to the video Numerical holographic reproduction may be performed by convolution integration assuming a plane wave, using the imaging device 30 and the numerical analysis processor 31a described in Fig. 3. This corresponds to the first and second numerical values shown in Figs. The same applies to the images obtained in the second and third embodiments, and it is clear that a clearer image can be obtained by performing numerical holographic reproduction by convolution integration assuming a plane wave.

FIG. 7 is a block diagram of a light wave vertical sectional tomography observation apparatus for reproducing a holographic real-time reflection image according to a fifth embodiment of the present invention. As shown in FIG. 7, for example, a laser oscillator having a wavelength of 1.3 μm having a high biological transmittance is provided in a high coherent light source 10a having a sufficiently long coherence length, and the emitted light is split into two by a beam splitter 13a. One of the two light beams is divided by a frequency shifter 22.
in a, performs frequency shift f _a so for example is transmitted using a photoacoustic device, using a beam expander 11a reflected by the return reflection mirror 19a as parallel light flux effective diameter, and the reference beam 20a. At this time, the reference light electric field E
_rf (t, r) is represented by the following equation.

[0039] In _{E rf (t) = E rf} exp [j2π (f-f _a) t] ... (20) where, E _rf the beam cross-sectional intensity represents the electric field amplitude of uniform light, f _a is Represents the shift frequency. The above equation (1
In 8), the origin is the photoelectric surface 2 where the two light beams interfere, and the phase term of the propagation distance is removed. The other split parallel light beam is transmitted through the frequency shifter 22b using, for example, a photoacoustic element, subjected to a frequency shift f _b , converted into a parallel light beam having an effective diameter using the beam expander 11b, and turned back into the reflecting mirror 19b. Reflected by the multi-lens array 23
And irradiates the measured object 12 with the divergent irradiation light group 20b. The divergent irradiation light group 20b propagates inside the object and is reflected on each tomographic plane inside the object. The reflected light group is reflected by the half mirror 13b, is combined with the reference light 20a, and becomes the incident image light 1. Since the diverging irradiation light group 20b can be approximated to a spherical wave, if the coordinate from the focal position by the multi-lens array 23 to the object to be measured 12 is the z-axis, the reflected light by irradiation light from one lens is expressed by the following equation. it can.

E _sf (t, r) = jk [2π (2z)] ⁻¹ E _sf (x, y, z) exp ｛j2π (f−f _b ) t−jk (x ² + y ² ) [2 ( 2z)] ^-1} + ^Σ _n the first term on the right side of _{E n exp (j2πft) ... (} 21) equation (21), the image plane of the reflected field E
_sf (x, y, z) represents spherical reflected light, and the second term represents background noise light based on multiple reflection and the like.

The reflected light causes two-beam interference with the reference light 20a on the photoelectric surface 2. An in-line hologram is formed on the photocathode 2 by interference between the spherically reflected object light and the parallel light reference light. The resulting photoelectron flow intensity I _d
(T, r) is given by the following equation. _{I d (t, r) =} Q | E rf (t) + E sf (t, r) | 2 = Q {E rf 2 + k 2 (4πz) -2 _{[E sf (x, y, z} ) ] ² + sigma ^{_{n | E n | 2 + Σ}} n E n E rf cos [2 [pi] f _a t] _{^{+ k (4πz) -1 E rf}} E sf (x, y, z) sin ^{[k (x 2 + y 2)} (4z) -1 - 2 [pi] f _c t]} (22) represents the equation (22) the second DC component light electron flow from equation the first term to the third term also comprises background noise light, also,
The fourth term is a high-frequency component that does not respond in time in the two-dimensional lock-in image intensifier 90, and is averaged due to interference by multiple scattered light to become a DC component. Beat frequency fifth term is due to heterodyne detection f _c = | f
_a −f _b | represents a video signal alternating-current component photoelectron flow to be observed, which is amplitude-modulated.

[0042] The photoelectron stream 3 is locked in integrating the frequency f _c as described in the two-dimensional lock-in image intensifier 90 of the embodiment. As a result, in the equation (22), although the frequency is different, the same control as in the first embodiment of FIG. 3 is performed, and a photoelectron flow represented by the following equation flows. _{I f (t, r) =} (Va / d) Q 1 I d (t, r) = {V d cos (2πf c t) / d} QQ 1 {E rf 2 + k 2 (4πz) -2 [E _sf (x, y, z)] ^{_{2 + Σ n | E n |}} 2 + Σ n E n E rf cos (2πf a t) + k (4πz) -1 E rf E sf (x, y, z) sin [k ( ^{x 2 + y 2) (4z} ) -1 -2πf c t _{]} = (V d / d)} QQ 1 {E rf 2 cos (2πf c t) + k 2 (4πz) -2 [E _sf (x, y, z)] _{^{2 cos (2πf c t) +}} Σ n | E n | 2 cos (2πf c t) + (1/2) k (4πz) -1 E rf E sf (x, y, z) {sin [k ^{(x 2 + y 2) (} 4z) -1 _{]} + (1/2) Σ n E} n E rf [cos _{[2π (f c + f a)} t ] + cos [2π (f _c -f _a) t] + ^{(1/2) k (4πz) -1} E rf E sf (x, y, z) {sin [k (x ^{2 y 2) (4z) -1 -2π} (2f c) t ]} (23) a DC component from the third equation of the first term on the right side of the equation (23) to the fourth term also includes background optical noise The fifth term is a high-frequency component that does not respond in time in the two-dimensional lock-in image intensifier 90, and is averaged into a DC component due to interference by multiple scattered light. Item 6 is the beat frequency f _c by heterodyne detection = | representing the video signal AC component light electron flow to be observed amplitude modulated | f _a -f _b. Its frequency f _c is obtained a signal from the frequency shifter 22a and 22b, is generated from the difference-frequency oscillator 15a, causing the AC applied voltage Va in synchronization via a control voltage oscillator 4 from terminal 5 generates between time T .

[0043] The photoelectron stream 3, as described in the two-dimensional lock-in image intensifier 90 of the embodiment, is the lock-in integration at that frequency f _c.
The DC component and the low frequency component including the background noise light from the first term to the fifth term on the right side of the third equation of the equation (23) are removed by the high-pass filter effect by the lock-in operation, and the sixth term Only flows into the front surface 6a of the microchannel plate 6, and is expressed by the following equation. _{I f (t, r) =} (V d / d) QQ 1 (1/2) k (4πz) -1 E rf E sf (x, y, z) sin ^{[k (x 2 + y 2)} (4z) ^{-1 -2π} (2f _c) t] ... (24)

This lock-in operation is performed by transmitting the voltage from the terminal 9 at the same time as applying the gate pulse for the T time, and the in-line hologram corresponding to the interference image is formed in a portion corresponding to the position of one lens. An image is observed on the phosphor screen 7.

The in-line hologram is formed by one lens at coordinates (x ₀ , y ₀ ) in the multi-lens array 23, and the phosphor screen 7 is expressed by the following equation for each coordinate of each lens. The observed interference fluorescence image is observed. I ₃ (t, r) = G (V _d / d) QQ ₁ (1/2) k (4πz) ⁻¹ E _rf E _sf (x ₀ , y ₀ , z) sin [k ｛(x−x _{0 ^{) 2 + (y-y 0}} 2)} (4z) -1 -2π (2f c) t ] ... (25) hologram interference image represented by this formula (25), the object inside the reflection point (x, y, z), that is, not only the information of the xy plane tomographic image of the object but also the information of the depth z axis, and the DC component and the low frequency component including the background noise light and the shift frequency f high-frequency component of _a is removed, only the video signal AC component light electron flow to be observed is amplified emphasized,
A clear image can be obtained.

The microlens array 23 is constituted by arranging flat microlenses having a focal length of several cm and a diameter of about 50 μm in a plate shape of about 500 × 500. Since the heterodyne detection is performed by interference between the reflected wave of these lenses due to the spherical wave and the plane wave, only the portion where the wavefront normal component of the spherical wave almost matches the normal of the plane wave,
It is possible to detect only a component that travels substantially straight inside the object and is reflected. In the case of a highly scattering substance such as a living body, multiple scattering occurs, and a large amount of background noise light is generated, masking an image surface to be observed.

Therefore, the in-line hologram is formed by the occurrence of interference fringes around this straight light component,
It will contain three-dimensional image information. At present, since the image resolution of the fluorescent screen 7 and the like is insufficient, interference fringes cannot be accurately projected, and thus a reproduced image can reproduce only insufficient depth information. We can expect to get better.

Next, in this embodiment, there is provided means for observing, by zooming, a tomographic image of an arbitrary depth plane of the measured object 12 from the in-line hologram image of the fluorescent screen 7 containing the three-dimensional image information. Therefore, it will be described below. As shown in FIG. 7, a spatial light modulator 26 is provided.
The image 24 of the fluorescent screen 7 is projected by the lens 25 on the back surface (writing surface) of the spatial light modulator 26. The spatial light modulator 26 having an incoherent / coherent light conversion function includes, for example, (Optical Engineer)
ring vol. 17, No. 4, p. 371, 19
78) are suitable. Since the projected image is based on the incoherent writing light, the projected image is converted into a polarization reflection image of the liquid crystal,
A parallel light beam 29a of linearly polarized light from a highly coherent laser light source 10b is passed through a polarizing beam splitter 27,
The reading light is applied to the front surface (reading surface) of the spatial light modulator 26. As a result, an in-line hologram, which is a write video signal, is reproduced by a laser beam, and the reflected light having an elliptically or circularly polarized light passes through the polarization beam splitter 27 to become a reproduction light 29b, which becomes a reproduction light of a tomographic image. .

The reproduction light 29b is a group of multiple divergent spherical waves because the reproduction light 29b is reproduction of reflected light by irradiation of the lens array. Each point (x ₀ ,
Since the reflected light group from y ₀ ) is divergent light having the same curvature, using the imaging device 30 having the zoom lens,
By focusing on an arbitrary z plane, that is, an arbitrary tomographic plane, a desired tomographic image can be observed in real time. Imaging device 3
The image shot at 0 is subjected to processing such as averaging in the image processing device 31, and the focal position is sequentially moved to record the image of each surface, thereby constructing a three-dimensional image.
It is possible to observe an arbitrary fracture surface image of the measured object. 32
Is the display device.

Obviously, if the reproduction light is viewed directly without using the zoom lens or the like, stereoscopic viewing is possible while having a narrow visual field. FIG. 8 is a configuration diagram of a light wave vertical section tomography observation apparatus using a numerical holographic reflection reproduction method showing a sixth embodiment of the present invention. As shown in FIG. 8, until the in-line hologram is visualized on the phosphor screen 7, the description is omitted, and the numerical holographic reproduction method will be described.

The image of the in-line hologram is projected on the imaging device 30 by the lens 25, and the in-line hologram is recorded in the image processing device 31 by converting the interference intensity of each pixel into a numerical value. Next, using the numerical analysis processor 31a, the convolution integration is executed on the numerical screen assuming the wavefront given by the following equation. jk [2π (2z)] ⁻¹ exp {−jk (x ² + y ² ) [2 (2z)] ⁻¹ } (26) As a result, a cross-sectional image on an arbitrary z plane is reproduced as a numerical screen. Can be. By sequentially moving the z position, performing the same numerical calculation, storing each reproduced numerical screen in the recording unit of the image processing device 31, and constructing a three-dimensional image in the same manner as described above, thereby enabling arbitrary measurement of the measured object. Observation of the cross section image of

In this method, numerical analysis takes time and real-time observation cannot be performed. However, it is easy to observe a desired tomographic image in a short time by developing a dedicated high-speed processor. is there. Further, it is possible to sequentially obtain reproduced images by numerical analysis, temporarily record the reproduced images at a video rate, and thereafter observe moving images on a real-time scale. FIG. 9 is a configuration diagram of a light wave vertical section tomography observation apparatus for observing a light transmission image according to a seventh embodiment of the present invention.

As shown in FIG. 9, the high coherence light source 1
For example, a laser oscillator having a high biotransmittance and a wavelength of 1.3 μm is provided in Oa, and the emitted light beam is split into two by a beam splitter 13a. One of the two split light beams is transmitted through the frequency shifter 22a using, for example, a photoacoustic element, frequency-shifted, converted into a parallel light beam having an effective diameter using the beam expander 11a, and reflected by the return reflecting mirror 19a. The reference light is assumed to be 20a. At this time, the reference light electric field E _rt
(T, r) is expressed by the following equation.

E _rt (t) = E _rt exp [j2π (f−f _a ) t] (27) where E _rt represents an electric field amplitude of light having a uniform beam cross-sectional intensity, and f _a is a shift. Indicates frequency. In the above equation (27), the photoelectric surface 2 where the two light beams interfere is taken as the origin, and the phase term of the propagation distance is excluded. The other split parallel beam is
The frequency shifter 22b is transmitted through, for example, a photoacoustic element, subjected to a frequency shift f _b , converted into a parallel light beam having an effective diameter using the beam expander 11b, reflected by the return reflecting mirror 19b, and reflected by the object 21 to be measured. Irradiate.

The irradiation light partially transmits inside the object and is attenuated by being absorbed or scattered by the properties of the object. The transmitted object light 20c is reflected by the half mirror 13b, is combined with the reference light 20a, and becomes the incident image light 1. This transmitted light can be expressed by the following equation. _{E st (t, r) =} E st (x, y) exp [j2π (f-f _b) t] _{+ Σ n E n exp (j2πft} ) ... (28) the first term on the right side of the equation (28) is transmitted _Represents transmitted object light holding an electric field E _st (x, y) having information on the image plane,
The term represents background noise light based on multiple reflection or the like.

The incident image light 1 causes two-beam interference on the photoelectric surface 2. A heterodyne interference image is formed on the photocathode 2 due to interference between the transmitted object light and the parallel light reference light. The resulting photoelectron flow is: I _e (t, r) = Q | E _rt (t) + E _st (t, r) | ² = Q ｛E _rt ² + [E _st (x, y)] ² + Σ _n | E _n | ² + Σ _{n E n E rt cos (2πf a} t) + E rt E st (x, y) cos (2πf c t)} ... (29) the third term from the second equation of the first term on the right side of the equation (29) Represents the DC component photoelectron flow including background noise light, and
The fourth term is a high-frequency component that does not respond in time in the two-dimensional lock-in image intensifier 90, and is averaged due to interference by multiple scattered light to become a DC component. Beat frequency fifth term is due to heterodyne detection f _c = | f
_a −f _b | represents a video signal alternating-current component photoelectron flow to be observed, which is amplitude-modulated.

[0057] The photoelectron stream 3 is locked in integrating the frequency f _c as described in the two-dimensional lock-in image intensifier 90 of the embodiment. As a result, although the frequency is different in the above equation (29), FIG.
The same control as in the first embodiment is performed, and a photoelectron flow expressed by the following equation flows. _{I p (t, r) =} (Va / d) Q 1 I e (t, r) = {V d cos (2πf c t) / d} QQ 1 {E rt 2 + [E _st (x, y) ] ^{_{2 + Σ n | E n |}} 2 + Σ n E n E rt cos (2πf a t) + E rt E st (x, y) cos (2πf c t)} = (V d / d) QQ 1 {E rt 2 cos (2πf _c t) + [E _st (x, y)] _{^{2 cos (2πf c t) +}} Σ n | E n | 2 cos (2πf c t) + (1/2) E rt E st (x, y _{) + (1/2) Σ n E} n E rt [cos _{[2π (f c + f a)} t ] + cos [2π (f _c -f _a) t]] _{+ (1/2) E rt E st} (x , y) cos [2 [pi (2f _c) t]} (30) DC components and low frequency components from the third equation of the first term on the right side of the equation (30) to the fourth term also includes background optical noise And the fifth term is a two-dimensional lock And a high-frequency component not responding time in emission image intensifier 90 are averaged for interference by multiple scattering light becomes a DC component. Item 6 is the beat frequency f _c by heterodyne detection = | representing the video signal AC component light electron flow to be observed amplitude modulated | f _a -f _b. Its frequency f _c is obtained a signal from the frequency shifter 22a and 22b, is generated from the difference-frequency oscillator 15a, causing the AC applied voltage Va in synchronization via a control voltage oscillator 4 from terminal 5 generates between time T .

[0058] The photoelectron stream 3 is locked in the integration at the frequency f _c as described in the two-dimensional lock-in image intensifier 90 of the embodiment. The DC component and the low frequency component including the background noise light from the first to fifth terms on the right side of the third equation of the above equation (30) are removed by the high-pass filter effect by the lock-in operation, and the sixth equation is obtained. Only the photoelectron flow represented by the term flows to the front surface 6a of the microchannel plate 6, and is expressed by the following equation. _{I p (t, r) =} (V d / d) QQ 1 (1/2) E rt E st (x, y) cos [2 [pi (2f _c) t] ... (31)

By the lock-in operation, the above equation (2)
Only the photoelectron current of the fifth term on the right side of 2) flows to the front surface 6a of the microchannel plate 6, and other DC components including background noise light are removed. By applying the gate pulse at the time T and transmitting the voltage from the terminal 9 at the same time, an image of an in-line hologram according to the interference image is formed at a portion corresponding to the position of one lens.

As a result, a light transmission image “E _rt E _st (x, y)” of the measured object including the reference light component represented by the following equation:
Is observed on the fluorescent screen 7 as a clear image from which background noise light, DC components and low-frequency components have been removed. _{I 4 (t, r) =} GI p (t, r) = G (V d / d) QQ 1 (1/2) E rt E st (x, y) cos [2π (2f _c) t] ... ( 32) This image is equivalent to an X-ray fluoroscopic image by light, but includes an interference fringe in the background because it is an interference image. Further, in order to obtain a clear perspective image, the image is subjected to numerical holographic reproduction by convolution integration assuming a plane wave using the imaging device 30 and the numerical analysis processor 31a described in the embodiment of FIG. Just do it. This is the same for the images obtained in the first, second, and third embodiments shown in FIGS. 3, 4, and 5, and the numerical holographic reproduction is performed by the convolution integration assuming the plane wave. For example, it is clear that a clearer image can be obtained.

FIG. 10 is a block diagram of a vertical section tomography observation apparatus for observing a holographic real-time optical fluoroscopic image according to an eighth embodiment of the present invention. As shown in FIG. 10, a high-coherence light source 10a is provided with, for example, a 1.3 μm wavelength laser oscillator having high biological transmittance, and the emitted light is split into two by a beam splitter 13a. One of the two split light beams is transmitted through the frequency shifter 22a using, for example, a photoacoustic element, subjected to _a frequency shift fa, converted into a parallel light beam having an effective diameter using the beam expander 11a, and reflected by the return reflecting mirror 19a. And the reference light 20a. At this time, the reference light electric field E _rt (t, r) is expressed by the following equation.

E _rg (t) = E _rg exp [j2π (f−f _a ) t] (33) where E _rg represents the electric field amplitude of light having a uniform beam cross-sectional intensity, and f _a is a shift. Represents frequency. In Expression (33), the origin is the photoelectric surface 2 where the two light beams interfere, and the phase term of the propagation distance is excluded. The other split parallel beam is
The frequency shifter 22b is transmitted using, for example, a photoacoustic element, subjected to a frequency shift f _b , converted into a parallel light flux having an effective diameter using the beam expander 11b, reflected by the return reflecting mirror 19b, and transmitted by the multi-lens array 23.
The light is converted into a diverging irradiation light group 20b and irradiates the measured object 21. The diverging irradiation light group 20b is transmitted through the inside of the object. The transmitted light group is reflected by the half mirror 13b and overlaps with the reference light 20a to become the incident image light 1. Since the diverging reference light group (diverging irradiation light group) 20b can be approximated to a spherical wave, if the coordinate from the focal position by the multi-lens array 23 to the measured object 21 is the z-axis, transmission by irradiation light from one lens is performed. Light can be expressed by the following equation.

E _sg (t, r) = jk (2πz) ⁻¹ E _sg (x, y, z) exp {j2π (f−f _b ) t−jk (x ² + y ² ) (2z) ⁻¹ } _{+ Σ n E n exp (j2πft} ) ... (34) transmitting the electric field E of the first term on the right side image plane of the formula (34)
_sg (x, y, z) represents spherical transmitted light, and the second term represents background noise light based on multiple scattering and the like.

The transmitted light causes two-beam interference with the reference light 20 a on the photoelectric surface 2. An in-line hologram is formed on the photocathode 2 by interference between the spherically reflected object light and the parallel light reference light. The resulting photocurrent intensity I
_f (t, r) is given by the following equation. _{I f (t, r) =} Q | E rg (t) + E sg (t, r) | 2 = Q {E rg 2 + k 2 (2πz) -2 _{[E sg (x, y, z} ) ] ² + sigma ^{_{n | E n | 2 + Σ}} n E n E rg cos (2πf a t) + k (2πz) -1 E rg E sg (x, y, z) sin ^{[k (x 2 + y 2)} (2z) -1 - 2 [pi] f _c t]} (35) is a DC component photoelectron stream containing background noise light from the second equation of the first term on the right side of the equation (35) to the third term, also fourth term 2 dimensional Lock-in Image Intensifier 9
At 0, it is a high frequency component that does not respond in time and is averaged due to interference by multiple scattered light to become a DC component. Beat frequency fifth term is due to heterodyne detection f _c = | f _a -
f _b | represents an AC component photoelectron flow of the video signal to be amplitude-modulated to be observed.

[0065] The photoelectron stream 3 is locked in integrating the frequency f _c as described in the two-dimensional lock-in image intensifier 90 of the embodiment. As a result, in the above equation (35), although the frequency is different, FIG.
The same control as in the first embodiment is performed, and a photoelectron flow represented by the following equation flows. _{I g (t, r) =} (Va / d) Q 1 I f (t, r) = {V d cos (2πf c t) / d} QQ 1 {E rg 2 + k 2 (2πz) -2 [E _sg (x, y, z)] ^{_{2 + Σ n | E n |}} 2 + Σ n E n E rg cos (2πf a t) + k (2πz) -1 E rg E sg (x, y, z) sin [k ( ^{x 2 + y 2) (2z} ) -1 -2πf c t _{]} = (V d / d)} QQ 1 {E rg 2 cos (2πf c t) + k 2 (2πz) -2 [E _sg (x, y, z)] _{^{2 cos (2πf c t) +}} Σ n | E n | 2 cos (2πf c t) + (1/2) k (2πz) -1 E rg E sg (x, y, z) {sin [k ^{(x 2 + y 2) (} 2z) -1 _{]} + (1/2) Σ n E} n E rg { [cos _{[2π (f c + f a)} t ] + cos [2π (f _c -f _a) t] } + (1/2) k (2πz ) -1 E rg E sg (x, y, z) {sin [ From ^{(x 2 + y 2) (} 2z) -1 -2π (2f c) t ]} (36) third equation of the first term on the right side of the equation (36) to the fourth term, the background noise light DC components and low frequency components,
The fifth term is a high-frequency component that does not respond in time in the two-dimensional lock-in image intensifier 90, and is averaged due to interference by multiple scattered light to become a DC component. Item 6 is the beat frequency f _c by heterodyne detection
= | F _a −f _b | represents the alternating current component photoelectron flow of the video signal to be observed which is amplitude-modulated. The frequency f _c is obtained a signal from the frequency shifter 22a and 22b, is generated from the difference-frequency oscillator 15a, via the control voltage oscillator 4 from the terminal 5, synchronized between the applied AC voltage Va T time occur Let it.

[0066] The photoelectron stream 3 is locked in the integration at the frequency f _c as described in the two-dimensional lock-in image intensifier 90 of the embodiment. The DC component and the low frequency component including the background noise light from the first term to the fifth term on the right side of the third equation of the above equation (36) are removed by the high-pass filter action by the lock-in operation, and the sixth equation is obtained. Term is beat frequency f by heterodyne detection
_c = _a video signal AC component photoelectron flow to be observed, which is amplitude-modulated by | f _a −f _b |. Only this photoelectron flow flows to the front surface 6a of the microchannel plate 6, and is expressed by the following equation. _{I g (t, r) =} (V d / d) QQ 1 (1/2) k (2πz) -1 E rg E sg (x, y, z) sin ^{[k (x 2 + y 2)} (2z) ^{-1 -2π} (2f _c) t] ... (37)

This lock-in operation is performed by applying a gate pulse at the time T and transmitting the voltage from the terminal 9 at the same time. An in-line hologram similar to the interference image is provided at a portion corresponding to the position of one lens. Is formed.

As a result, a light transmission image “E _rg E _sg (x,
y) ”is observed on the phosphor screen 7 as a clear image from which background noise light and DC components have been removed. I ₅ (t, r) = G (V _d / d) QQ ₁ (1/2) k ^{_{(2πz) -1 E rg E sg}} (x, y, z) sin ^{[k (x 2 + y 2)} (2z) -1 -2π (2f c) t ] ... (38) the image is, X-rays by the light Although it is equivalent to a perspective image, since it is an interference image, it contains fine interference fringes in the background.

In this operation, the gate pulse is applied at the time T and the voltage is transmitted from the terminal 9 at the same time, so that an image of an in-line hologram according to the interference image is formed at a portion corresponding to the position of one lens. Is done.

The in-line hologram is formed by one lens at coordinates (x ₀ , y ₀ ) in the multi-lens array 23, and the phosphor screen 7 is expressed by the following equation for each coordinate of each lens. The observed interference fluorescence image is observed. _{I 5h (t, r) =} G (V d / d) QQ 1 (1/2) k (2πz) -1 E rg E sg (x 0, y 0, z) sin {k [(x-x _{0 ^{) 2 + (y-y 0}} ) 2 ] _{^{(2z) -1 -2π (2f c}} ) t} ... (39)

The hologram interference image expressed by the equation (39) is three-dimensional information of the reflection point (x, y, z) inside the object,
That is, information on the depth z-axis as well as information on the xy plane perspective image of the object is included.

The microlens array 23 is constituted by arranging flat microlenses having a focal length of several cm and a diameter of about 50 μm to less than about 500 × 500. Heterodyne detection due to interference between the transmitted wave and the plane wave of these lenses due to the spherical wave is only the part where the wavefront tangent component of the spherical wave almost matches the plane wave, so it travels almost straight inside the object, Only the transmitted component can be detected. In the case of a highly scattering substance such as a living body, multiple scattering occurs, and a large amount of background noise light is generated, which masks the image surface to be observed. Therefore, the in-line hologram is formed by generating interference light centering on the straight light component, and includes three-dimensional image information.

Next, in this embodiment, there is provided a means for observing, by zooming, a fluoroscopic tomographic image of an arbitrary depth plane of the measured object from the in-line hologram image of the fluorescent screen 7 containing the three-dimensional image information. The operation principle is the same as that described with reference to FIG. FIG. 11 is a block diagram of an apparatus for observing a light wave vertical cross section tomography of a real-time optical fluoroscopic image by a numerical holography reproducing method according to a ninth embodiment of the present invention.

In FIG. 11, until the in-line hologram is visualized on the fluorescent screen 7, the operation is exactly the same as that in FIG. Further, the numerical holographic reproduction method is completely the same as that of the sixth embodiment in FIG. 8, and the description of that part is omitted. It is apparent that the present invention is based on the present invention even if the configurations shown in the respective embodiments are appropriately changed without changing the gist of the present invention.

The present invention is not limited to the above-described embodiment, and various modifications are possible based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

[0076]

As described above in detail, the present invention provides a photocathode for converting incident image light into a two-dimensional spatially modulated photoelectron stream by square detection, and a two-dimensional electron emission of the photoelectron stream. A microchannel plate with a back electrode on the front and rear sides that also has a multiplying secondary electron generation function, and a multiplication secondary electron flow by the multiplication secondary electron generation function is converted into fluorescent light, and an image of incident light is obtained. A two-dimensional lock-in image intensifier equipped with a phosphor screen that also serves to superimpose and accumulate electrons for a certain period on the excited fluorescence level in the fluorescent medium only for the signal AC component is provided. When light is subjected to heterodyne detection on the photocathode with two-dimensional image light of two-beam interference, the distribution of the photoelectron current generated from the photocathode is determined based on the DC component photoelectron current and the heterodyne detection at each pixel. A video signal AC component photoelectron stream that has undergone amplitude modulation, the amplitude between the photocathode and the front surface electrode of the microchannel plate so as to change over time in synchronization with the frequency of the amplitude modulation. Means for applying an alternating voltage equal to the frequency of the modulation;
Means for applying a constant voltage between the electrode on the front surface of the microchannel plate and the electrode on the rear surface of the microchannel plate to multiply the two-dimensional electron density cross section distribution according to an image on the front surface of the microchannel plate; Applying a constant voltage between an electrode on the rear surface of the microchannel plate and an electrode on the phosphor screen to generate a two-dimensional fluorescence intensity cross-sectional distribution similar to a two-dimensional electron density cross-sectional distribution according to an image on the front surface of the microchannel plate. Means for performing two-dimensional lock-in amplification in accordance with an integration operation of a narrow band filter for superimposing and accumulating excitation electrons for a certain period of the frequency of the amplitude modulation of the two-dimensional fluorescence intensity cross-sectional distribution on the fluorescent medium; The background noise optical DC component and low frequency component of the modulated incident photoelectron stream are removed, and based on the heterodyne detection. The vertical cross-section tomography observation device, characterized in that the excitation electrons generated by only the alternating current photocurrent of the video signal undergoing amplitude modulation can be superimposed and accumulated in the fluorescent medium, enabling observation of living organisms and various light scattering objects. By using a reflection tomographic image, a transmission image, and a microlens array at the depth of the object, a three-dimensional internal image of these objects can be observed in a wide dynamic range in real time.

With such an observation means, it is not necessary to irradiate light from a 360-degree direction as in X-ray CT.
It provides a means to easily observe a tomographic image of a living body only by irradiating an optical probe from one direction. In addition, there is a great demand not only in the semiconductor industry, new material industry, food industry, orchard and horticulture industry, etc., and the present invention can sufficiently meet these demands.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a two-dimensional lock-in image intensifier composed of a proximity type or a vacuum tube type showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of incident light intensity and a voltage applied to a photocathode of the two-dimensional lock-in image intensifier shown in FIG.

FIG. 3 is a configuration diagram of a basic light wave vertical cross-section tomography observation apparatus for observing a reflected tomographic image according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram of a light wave vertical section tomography observation apparatus for observing a reflected tomographic image according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram of a light wave vertical cross-section tomography observation apparatus with an optical fiber scope showing a third embodiment of the present invention.

FIG. 6 is a configuration diagram of a light wave vertical section tomography observation apparatus for observing a light reflection tomographic image according to a fourth embodiment of the present invention.

FIG. 7 is a configuration diagram of a light wave vertical section tomography observation apparatus for performing a holographic real-time reflection reproduction method according to a fifth embodiment of the present invention.

FIG. 8 is a configuration diagram of a light wave vertical section tomography observation apparatus using a numerical holographic reflection reproduction method showing a sixth embodiment of the present invention.

FIG. 9 is a configuration diagram of a light wave vertical cross-section tomography observation apparatus for observing a light transmission image according to a seventh embodiment of the present invention.

FIG. 10 is a configuration diagram of a light wave vertical section tomography observation apparatus for observing a holographic real-time optical fluoroscopic image according to an eighth embodiment of the present invention.

FIG. 11 is a configuration diagram of a light wave vertical cross-section tomography observation apparatus of a real-time optical fluoroscopic image by a numerical holography reproducing method according to a ninth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Incident image light 2 Photocathode 3 Photoelectron flow 4 Control voltage oscillator 5, 9 Terminal 6 Micro channel plate 6a Front electrode 6b Rear electrode 7 Phosphor screen 8 Multiplied secondary electron flow 10 Low coherent light source 10a Coherence length is sufficiently long High coherence light source 10b High coherent laser light source 11, 11a, 11b Beam expander 12, 21 Object to be measured 12a Stage 13, 13a Beam splitter 13b Half mirror 14, 19a, 19b Reflector 14a Transducer 15 Oscillator 15a Differential frequency oscillator 16 Shutter 16a Drive circuit 17a, 17b, 17c, 17d, 25, 28a Lens 18a Parallel light flux 18b, 20a Reference light 18c Reflected object light 20b Divergent irradiation light group (divergent reference light group) 20c Transmitted object light 22 , 22b Frequency shifter 23 Multi-lens array 24 Video 26 Spatial light modulator 27 Polarization beam splitter 28 Optical fiber scope 28b End face of the other end of optical fiber scope 28c End face of optical fiber scope 29a Parallel light flux 29b Reproduction light 30 Imaging device 31 Image processing 31 Image processing Device 31a Numerical analysis processor 32 Display device 90 Two-dimensional lock-in image intensifier 90a, 90b Window 100 Two-dimensional lock-in image intensifier device

Claims (12)

[Claims] 1. A photocathode for converting incident image light into a two-dimensionally spatially modulated photoelectron stream by square detection, a front part having a function of generating a secondary electron by multiplying the photoelectron stream by two-dimensional electron emission, and A microchannel plate with a back electrode on the rear surface, fluorescence conversion of the two-dimensional multiplied secondary electron flow by the multiplying secondary electron generation function, and excitation fluorescence level in the fluorescent medium when the secondary electron flow is AC. A two-dimensional lock-in image intensifier equipped with a phosphor screen which also has a function of superimposing and accumulating electrons for a certain period at each position so that a multiplied image can be observed. Cross-sectional tomography observation device. 2. The light wave vertical section tomography observation apparatus according to claim 1, wherein the two-dimensional lock-in image intensifier is provided, and the incident image light is two-dimensional image light of two-beam interference, and heterodyne detection is performed on the photoelectric surface. When the distribution of the photoelectron current generated from the photocathode is composed of a DC component photoelectron current and a video signal AC component photoelectron current that has been subjected to amplitude modulation based on the heterodyne detection in each pixel, Means for applying an AC voltage equal to the frequency of the amplitude modulation between the photocathode and the electrodes on the front surface of the microchannel plate so as to change over time in synchronization with the frequency; The two-dimensional electron density cross-section distribution according to Means for applying a constant voltage between the electrodes on the rear surface of the channel plate to multiply two-dimensional electrons;
Means for applying a constant voltage between an electrode on the rear surface of the microchannel plate and an electrode on the phosphor screen to generate a two-dimensional fluorescence intensity cross-sectional distribution similar to a two-dimensional electron density cross-sectional distribution according to an image on the front surface of the microchannel plate. Performing two-dimensional lock-in amplification in accordance with an integration operation of a narrow band filter that superimposes and accumulates excitation electrons for a certain period of the frequency of the amplitude modulation of the two-dimensional fluorescence intensity cross-sectional distribution on the fluorescent medium, Removing the DC component and the low frequency component including the background noise light of the incident photoelectron flow receiving the
A light wave vertical cross-section tomography observation apparatus characterized in that excitation electrons for a fixed period by only a video signal AC component photoelectron stream subjected to amplitude modulation based on heterodyne detection can be superimposed and accumulated in a fluorescent medium for observation. 3. The light wave vertical cross-section tomography observation apparatus according to claim 1, wherein when constructing the two-dimensional image incident light of the two-beam interference, a light beam from a low coherent light source is substantially parallelized using a lens system. Means for dividing the parallel light beam into two, means for applying a phase shift to one of the divided light beams and reflecting the same as reference light, and irradiating the other light beam to the object to be measured, and the optical path difference between the reference light and Means for forming incident light by multiplexing and superimposing object light from the deep tomographic reflection surface of the measured object within the low coherent length and the reference light to form a two-beam interference image; and A video signal AC component photoelectron flow of the deep tomographic reflection surface which is incident on the photocathode and is subjected to amplitude modulation based on the phase shift amount is generated, and an AC voltage having the frequency of the amplitude modulation is applied to the photocathode and the microchannel. 3. A DC component and a low-frequency component including background noise light by amplifying and emphasizing only a two-dimensional lock-in image of the deep tomographic reflection surface based on the same operation as in claim 2 applied between electrodes on the front surface of the flannel plate. A light wave vertical cross-section tomography observation apparatus characterized in that the observation can be performed by removing the light. 4. The light wave vertical cross-section tomography observation apparatus according to claim 2, further comprising means for changing the reference light path length in the depth direction every time one deep tomographic reflection image is obtained. Lightwave vertical section tomography observation device. 5. An apparatus for observing a vertical cross section of a light wave according to claim 3, further comprising a lens in an optical path of said parallel light beam, and a lens for Fourier transform of a lens reflecting surface in an optical path of said object optical path. Further comprising a lens for inverse Fourier transform in front of the photocathode, forming the deep reflection image on the photocathode, including a lens in the reference light path, and an operation with the lens for inverse Fourier transform. By irradiating the photocathode with reference light of a substantially parallel light beam,
A vertical cross-section tomography observation apparatus for light waves, wherein the deep reflection image constitutes incident light of a two-beam interference image. 6. The light wave vertical tomography observation apparatus according to claim 4, wherein a part of an optical path to the object light is an optical fiber scope. 7. The light wave vertical cross-section tomography observation apparatus according to claim 2, wherein, when composing the image incident light of the two-beam interference, means for splitting a light beam from a highly coherent light source into two, and one of the split light beams Means for applying a frequency shift to a substantially parallel light beam using a lens system and reflecting it as reference light, and applying another frequency shift to the other light beam to make a substantially parallel light beam using a lens system and irradiating the object to be measured with an object. Means for forming a two-beam interference image by multiplexing the reflected object light from the deep part and the reference light to form a two-beam interference image, and forming an alternating voltage that changes at a heterodyne beat frequency equal to the difference frequency of the frequency shift. The voltage is applied between the photocathode and the electrode on the front of the microchannel plate,
By operating the two-dimensional lock-in image intensifier, it is possible to amplify and observe only the two-dimensional lock-in image of the reflected image of the reflected object light from which the DC component and the low-frequency component including the background noise light have been removed. A light wave vertical section tomography observation apparatus characterized by the following. 8. The light wave vertical cross-section tomography observation apparatus according to claim 2, wherein a means for splitting a light beam from a high coherent light source into two when forming the image incident light of the two-beam interference, and one of the split light beams Means for applying a frequency shift to a substantially parallel light beam using a lens system and reflecting it as reference light, and applying another frequency shift to the other light beam to make a substantially parallel light beam using a lens system and performing multiple divergence through a multi-lens array. Means for irradiating the object to be measured with the multiple divergent light group and multiplexing and superimposing the object light reflected from the deep part of the object and the reference light to form a two-beam interference image of a multiplex in-line hologram; And an AC voltage that changes at a heterodyne beat frequency equal to the difference frequency of the frequency shift is applied to the photocathode and the microchannel plate. A light wave which is applied between electrodes on a front surface of the multiplexed hologram and which can observe a two-dimensional lock-in image in which only the interference light of the multiple in-line hologram is amplified and emphasized by the operation of the two-dimensional lock-in image intensifier. Vertical section tomography observation device. 9. The light wave vertical cross-section tomography observation apparatus according to claim 2, wherein, when composing the image incident light of the two-beam interference, means for splitting a light beam from a highly coherent light source into two, and one of the split light beams Means for applying a frequency shift to a substantially parallel light beam using a lens system and reflecting it as reference light, and applying another frequency shift to the other light beam to make a substantially parallel light beam using a lens system and transmitting the same to the object to be measured. The transmitted object light and the reference light are combined and superimposed to form 2
Forming incident light by means for forming a light beam interference image;
An AC voltage that changes at a heterodyne beat frequency equal to the difference frequency of the frequency shift is applied between the photocathode and the electrodes on the front surface of the microchannel plate, and the operation of the two-dimensional lock-in image intensifier causes the background noise light to change. 1. A light wave vertical cross-section tomography observation apparatus characterized in that only a two-dimensional lock-in image of a perspective image of transmitted object light from which a DC component and a low-frequency component including the above are removed can be amplified and observed. 10. The light wave vertical cross-section tomography observation apparatus according to claim 2, wherein, when composing the image incident light of the two-beam interference, means for splitting a light beam from a highly coherent light source into two, and one of the split light beams Means for applying a frequency shift to a substantially parallel light beam using a lens system and reflecting it as reference light, and applying another frequency shift to the other light beam to make a substantially parallel light beam using a lens system and performing multiple divergence through a multi-lens array. A means for forming a light group and a means for transmitting the multiple divergent light group to an object to be measured, and multiplexing and superimposing the transmitted object light and the reference light to form interference incident image light of a multiplex in-line hologram. The AC voltage, which constitutes light and changes at a heterodyne beat frequency equal to the difference frequency of the frequency shift, is applied to the photocathode and the front surface of the microchannel plate. Applied between the electrodes of the unit, and by the operation of the two-dimensional lock-in image intensifier,
A two-dimensional lock-in image obtained by amplifying and emphasizing only the interference light of the multiplex in-line hologram so as to be able to amplify and observe the two-dimensional lock-in image. 11. A light wave vertical cross-section tomography observation apparatus according to claim 8, wherein a lens for inputting the interference light image of the phosphor screen to an incoherent / coherent image conversion element, and a coherent image from the image conversion element. Equipped with a high coherent light source for reproducing read-out multiplex in-line holography, and further equipped with a zoom lens so that an image of an arbitrary cross section in the deep part of the object can be observed at the imaging focal position by removing background noise light and a DC component. A light wave vertical cross-section tomography observation device comprising an imaging device. 12. The light wave vertical section tomography observation apparatus according to claim 8 or 10, wherein said means for imaging said interference fringe image of said fluorescent screen and said imaging screen, which is a multiplex in-line hologram, are inputted to a computer and subjected to numerical calculation. An apparatus for observing a vertical cross section of a light wave, comprising: means for reproducing a hologram; and means for displaying the reproduced image.