JP3447344B2 - Optical image reconstruction device - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an optical image reconstruction device.

[0002]

2. Description of the Related Art In a conventional optical image reconstructing apparatus using optical equipment, it may be difficult to input an image from an arbitrary direction due to structural restrictions. Consider a microscope as an example.
FIG. 11 shows a configuration diagram of a conventional general microscope. Generally, a microscope is constructed so that an image of an object placed on a stage surface perpendicular to the optical axis direction of the optical system is formed. In the microscope 10 shown in FIG. 11, in the direction perpendicular to the optical axis of the objective lens 14, that is, in the horizontal direction, an arbitrary portion of the object can be set within the visual field by the XY stage drive unit 12. The axial Z stage drive unit 13 is used for focus adjustment, and a normal observation method cannot obtain a tomographic image in the optical axis direction.

As an example of reconstructing a tomographic image in the optical axis direction by a digital image processing method, reference is made to: A. Erhardt, G. Zinser, D. Komitowski and J.
Bille, Appl. Opt., 24, 194-200 (1985).
In this paper, a three-dimensional optical image is obtained by inputting an image corresponding to a set in-focus surface while stepwise moving the position of an in-focus object surface (hereinafter referred to as in-focus surface) in the optical axis direction. And the three-dimensional optical transfer function (3-dimensio
A method of recovering a spatial frequency component deteriorated at the time of image input by operating an inverse filter of nal Optical Transfer Function (3-dOTF) is shown.

However, in such a method, the spatial frequency characteristic in the optical axis direction is greatly deteriorated as compared with the surface direction due to the limitation of the numerical aperture (NA) of the microscope objective lens. However, it is difficult to obtain a tomographic image with excellent resolution. Further, when the inverse filter is operated, the spatial frequency component whose 3-dOTF characteristic is extremely inferior is excessively emphasized, so that the S /
N can be very bad.

On the other hand, optical emission CT (optical ECT) is known as a method for obtaining a tomographic image of a plasma emission phenomenon in a cylindrical tube such as a fluorescent lamp or a Geisler tube. In particular, Japanese Patent Laid-Open No. 3-1
In Japanese Patent No. 2524, a method is proposed in which light emission from the inside of a cylindrical tube in a set cross section is imaged by an optical system composed of a slit and a cylindrical lens, and the image is picked up by an image sensor such as a CCD camera. Further, in this publication, when obtaining a tomographic image by a CT reconstruction algorithm from an image from each direction obtained by rotating the optical imaging unit in the plane direction of the set cross section, each point on the tomographic plane on the imaging plane is obtained. A method of performing CT reconstruction by a successive approximation method in consideration of a contribution rate obtained from an imaging pattern is shown.

However, in this method, when the depth of focus of the optical imaging system is smaller than the inner diameter of the target cylindrical tube, the contribution rate from the portion deviated from the focusing surface is dispersed in the image pickup surface, Projection data necessary for reconstruction may not be obtained. On the contrary, if the depth of focus is set to be sufficiently deeper than the inner diameter of the target cylindrical tube, such an optical system will have poor spatial frequency characteristics, and thus a reconstructed image with excellent resolution cannot be obtained.

[0007]

However, the above-mentioned conventional methods in the field aiming to obtain an optical tomographic image are limited to optical characteristics such as the spatial frequency band of the optical imaging system and the depth of focus. However, in order to obtain an optical tomographic image with excellent resolution in any angle direction, no consideration is given to inputting and reconstructing an image based on the optimum conditions.

The optical image reconstructing apparatus of the present invention has been made by paying attention to such a problem, and an object thereof is an optical tomographic image or an optical three-dimensional image excellent in resolution in an arbitrary angular direction. It is an object of the present invention to provide an optical image reconstructing device that can reconstruct an optical image and is practically useful.

[0009]

In order to achieve the above-mentioned object, the optical image reconstructing apparatus according to the first invention comprises:
The same numerical aperture (Numerical Aperture: hereafter) radially arranged so that the optical axis intersects at a predetermined point in the object space
N. A. ) , Image pickup means for converting an image of the object formed by each of the N optical image formation systems into an electric image signal, and the image pickup means. an image memory for storing the N pieces of electrical image signals, using N electric image signal stored in said image memory, a tomographic image of parallel object to the optical axis of the optical imaging system In the optical image reconstructing device having a tomographic image reconstructing means for reconstructing, the number N of the optical imaging systems is an angle α.
(However, the N.A.
α and n are refractive indices), N = 180 ° / (2
α) and are evenly arranged in the angular direction. Also, the second
The optical image reconstructing device according to the invention of claim 1, wherein an optical image forming system capable of arbitrarily setting the relative angle of the optical axis with respect to the object, and an image of the object formed by the optical image forming system with respect to the object. while changing relative direction of the optical axis of the optical imaging system, N
Times, an imaging means for converting an electrical image signal, an image memory for storing the N pieces of electrical image signal captured by the imaging means, the N pieces of electrical image signals stored in the image memory An optical image reconstruction device having a tomographic image reconstruction means for reconstructing a tomographic image of an object parallel to the optical axis of the optical imaging system using the optical axis of the optical imaging system.
The set number N of directions is the angle α (however,
Numerical aperture N.V. A. (Numerical Aperture) to nsin α,
n is the refractive index), N = 180 ° / (2α)
And are set at equal intervals in the angular direction. Also, the third
An optical image reconstruction device according to the invention is the first or second invention.
Related to the optical image reconstruction device,
The stage is the electrical image stored in the image memory.
A matrix calculator that performs a linear calculation between a signal and a predetermined matrix
The predetermined matrix is provided in each of the imaging means.
Transmitted by the optical imaging system to the image pickup device
Define a sensitivity distribution function that represents the light intensity distribution in body space,
Image input determined by the optical imaging system and the image pickup means
Toko force system was linearly defined using the number of the sensitivity distribution function
Is a generalized inverse matrix of b.

[0010]

EXAMPLE The outline of this example will be described below. First, the image input conditions required when reconstructing a tomographic image using optical imaging will be described. In the following description, when discussing the spatial frequency characteristics of the optical imaging system, N. A. The optical system of a large optical microscope will be dealt with, but an incoherent optical system linear to the light intensity will be assumed by further assuming a fluorescence microscope. Although this setting condition is the simplest case for the reconstruction problem of the optical tomographic image,
It is also practically useful as a means for observing a minute and transparent biological sample.

The image forming system of the optical microscope is relatively close to an ideal system, and it can be considered that it is a space invariant system with respect to a three-dimensional position in an object space region smaller than the focal length. Wave-optical analysis assuming the diffraction limit gives a good approximation. FIG. 7 shows a conceptual diagram of 3-dOTF representing the three-dimensional spatial frequency characteristic of the fluorescence microscope. It is generally considered that an optical imaging system configured by using a spherical lens has the same characteristics in any radial direction within a plane perpendicular to the optical axis. Therefore, in FIG. 7, the spatial frequency axis ρ in the arbitrary radial direction in the plane perpendicular to the optical axis is defined as 3-dOTF.
And the spatial frequency axis φ in the optical axis direction.

As can be seen from FIG. 7, the spatial frequency characteristic in the vicinity of the optical axis is greatly deteriorated. The region in which this characteristic drops is called a missing cone because it has a three-dimensional conical shape. Due to the presence of this missing cone, it is not possible to reconstruct a tomographic image with excellent resolution in the optical axis direction as well as in the in-focus plane from the image input using an optical microscope whose optical axis is fixed. . The entry angle α in the range where the spatial frequency characteristic with respect to the ρ axis shown in FIG. 7 is the numerical aperture (Numerical Aperture) of the optical imaging system.
A. ) Depends on. Therefore, in order to have a spatial frequency characteristic in any direction in the fault plane, that is, to fill the missing cone, N = 180
It is considered that it is necessary to set the optical imaging system in the direction of ° / (2α). For example, N. A. = For optical imaging system using no 0.5 oil ^{immersion, α = sin -1 (0.5)} = 6
Since it is 0 °, it suffices to provide the optical imaging system in N = 180 ° / 120 ° = 3 directions.

Therefore, as a microscope apparatus, if three lens barrels having different angle directions of 120 ° are radially arranged,
Images can be input without missing in any direction. 3-dOTF in the form of such a microscope
Is shown in FIG.

On the other hand, the optimum sampling interval during image input is determined by the spatial frequency band of the optical image forming system.
The maximum spatial frequency bands ρ ₀ and φ ₀ in the focusing plane perpendicular to the optical axis shown in FIG. 7 and in the optical axis direction are both determined by the size of the limited region of the pupil function defined by the diffraction limit. The optical imaging system N.V. A. Depends on. The sampling interval in the focusing plane, for example, the interval between adjacent light receiving elements in an image pickup device in which light receiving elements such as a CCD camera are two-dimensionally arranged, is 1 / (2
It should be fine if it is finer than the pitch corresponding to ρ ₀ ).

On the other hand, the sampling interval in the optical axis direction, that is, the set focusing surface interval on the assumption that an image is input while moving the focusing surface of the optical imaging system in the optical axis direction is 1 as well. It is understood that the pitch is finer than the pitch corresponding to / (2φ ₀ ). This can be explained as follows with reference to FIG. When sampling in the direction of the optical axis at the pitch τ, the first-order spectrum center exists at the position of 1 / τ on the φ-axis in terms of spatial frequency, but the 0th-order spectrum centered at the origin and the first-order spectrum center 1 order spectrum center is present outside the position of 2 [phi ₀ in consideration of phi ₀ is the maximum bandwidth of the optical axis direction to avoid having aliasing overlap and spectrum, that is, 1 / ( It can be seen that sampling may be performed finer than the pitch corresponding to 2φ ₀ ).

As described above, the minimum number of directions and sampling conditions necessary for reconstructing an optical tomographic image are derived from the spatial frequency characteristics of the optical imaging system. However, even if images are input based on these conditions, there has been no advantageous theory for reconstructing a tomographic image using these images. Therefore, in this embodiment, a method of reconstructing a tomographic image by the generalized inverse matrix method described below is proposed.

First, while the relational expression of the object space and the optical imaging system is defined by a continuous system, the continuous object is observed discretely considering that the image is input as discrete information by sampling. The system is defined by the following equation.

[0018]         g = H {f (r)} (1) However, f (r): an original object defined by a continuous function.

R = (r _x , r _y , r _z ): Three-dimensional Cartesian coordinates defined in the object space. H {}: Observation operator. g = [g ₁ , g ₂ , ..., G _M ] ^t : observation vector. The element g _i of g is expressed by the following equation.

[0020]

[Equation 1]

Here, the sensitivity distribution function is a function defined as a light intensity characteristic distribution in the object space transmitted by the optical imaging system for each image pickup element in the image pickup means, for example, each light receiving element of a CCD camera. Is. Considering H {} as a conversion matrix from a continuous system (the number of ∞ elements) to a vector having the number of elements M, the rank of H becomes M at the maximum. The pseudo-inverse matrix solution method by singular value decomposition (SVD) can be applied to the reconstruction problem for the system formulated as described above. That is, the estimation f _e (r) of the original object can be obtained by the following equation.

F _e (r) = H ⁻ {g} = H ^t {(HH ^t ) ⁻ g} (3) where H ^t {} is from discretely observed data to the continuous object space. It is an inverse conversion operator. Also,
(HH ^{t) -} is the pseudo-inverse matrix of HH ^t, is determined as follows. First, the M × M matrix HH ^t is eigenvalue decomposed as follows.

(HH ^t ) U = UΛ (4) When the rank of HH ^t is R ≦ M, (HH ^t ) ⁻ is defined as follows. _{^{(HH t) - = U R}} Λ R -1 U R t (5) In addition, U _R is a matrix of composed M × R eigenvector corresponding to the R number of eigenvalues, lambda _R ^-1 is a diagonal It is an R × R matrix constructed by arranging the reciprocals of R eigenvalues in the components.

Next, in the image forming system of the optical microscope, the continuous-
Define a discrete model and find the sensitivity distribution function. For simplicity, first, assuming a case where the optical axis and the focusing surface are fixed, a conceptual diagram of this system is shown in FIG. A system in which an original object f (r) defined in a three-dimensional space is imaged as a three-dimensional optical image g (r ') by a transfer function s (r; r') is defined as a continuous-continuous system as follows. To do.

[0025]

[Equation 2]

The microscopic optical image g (r ') is r' is sampled on the imaging surface set at the position of _z, discrete values g
_i (i = 1, 2, ..., M) is detected. The image input system by the continuous-discrete transform is defined as follows.

[0027]

[Equation 3] However, t = (t _x , t _y ): two-dimensional orthogonal coordinates defined on the imaging surface.

D _i : integration range at the i-th sampling (size of detection element) b (t): Window function at the time of sampling.

G (t): distribution of the three-dimensional optical image g (r ') on the imaging surface t. s (r; t): Transfer function from the three-dimensional object space r to the two-dimensional imaging surface t. Assuming that the integration range D _i is the same for any image sensor and the window function b (t) is a function independent of position, the sensitivity distribution function h _i (r) is defined by the following equation.

[0030]

[Equation 4]

Here, the transfer function s (r; t) will be considered. According to this condition, a point spread function PSF (Point Spread Function) whose position is invariable on the image plane can be defined. Therefore, the PSF on the imaging surface is defined as PSFo (t; ζ) due to defocus ζ.

[0032]

[Equation 5] The object space r is defined by a distance z between the focusing surface and the object surface and a two-dimensional coordinate q = defined in a surface perpendicular to the optical axis (parallel to the image pickup surface).
Redefining with (q _x , q _y ), the distance z is associated with the defocus ζ due to the imaging relationship of the optical system. Furthermore P
Considering SFo (t; ζ) is the image distribution of the points f (0; z) in the object space, the points f at arbitrary coordinates
The image distribution of (q; z) can be represented by (t-mq; z). However, m is the total magnification of the microscope optical system. Therefore, the transfer function s (r; t) is defined by the following equation.

S (r; t) = s (q; z; t) = o (t-mq; z) (10) where, for o (t-mq; z), the relationship between z and ζ should be substituted. Is a PSF in which o (t-mq; ζ) is redefined by By substituting the equation (10) into the equation (8), the sensitivity distribution function h _i (r) is obtained as follows.

[0034]

[Equation 6]

From the above consideration, the sensitivity distribution function h _i (r)
Is calculated from PSFo (t; z) in consideration of defocus. Further, the sensitivity distribution function under the conditions such as the rotation of the optical axis and the movement of the focusing surface can also be obtained according to the above description as described later.

As described above, the optical image reconstruction method according to this embodiment is based on the model in which the continuous-discrete relationship is clarified, and has the following advantages. (1) In principle, it is a method of estimating a continuous object from discrete data.

(2) Since the interpolation function is not included, deterioration or contradiction due to interpolation does not occur in conversion of the rotating coordinate system ← → Cartesian coordinate system. (3) The image input condition can be directly reflected on the image quality of the reconstructed image without including the assumption for the object.

However, when applied to this method, it is necessary to discretely define the sensitivity distribution function and the object space, which should originally be defined in a continuous system, for calculation processing. However, if a continuous system is defined by discrete elements that are sufficiently small with respect to the size of the light receiving element, it is possible to handle the continuous system practically approximately. In other words, if the reconstruction is performed based on this principle without using the interpolation function, the advantage of this method can be utilized.

The first embodiment of the present invention will be described below. FIG. 1 shows the configuration of the first embodiment of the present invention. The configuration is roughly divided into a microscope device 100, an image processor 200, and a TV monitor 300.

The microscope apparatus 100 includes a transparent tube 102 on a stage 101 as a means for holding and fixing a sample.
Are vertically installed, and three microscopes are provided radially around the transparent tube 102. In each microscope, N. A. = 0.5 objective lens 103 ₁
, 103 ₃ are installed on the lens barrels 104 _{1 to} 104 ₃ , and the objective lenses 103 _{1 to} 103 ₃ are further driven in the optical axis direction by the focusing drive devices 105 _{1 to} 105 ₃ to obtain the present microscope. The focusing surface of the optical system is driven.

TV cameras 106 _{1 to} 106 ₃ are provided at the ends of the lens barrels 104 _{1 to} 104 ₃ to pick up microscopic images. The microscope device 100 is based on a fluorescence microscope for observing the emission distribution of a fluorescently stained biological sample, and an excitation light source device for uniformly irradiating a target object space region to be observed is required, but in FIG. 1, it is complicated. Illustration is omitted to avoid this. The configuration around the sample in the microscope apparatus 100 is shown in FIG. A sample dyed with a fluorescent substance suspended in a liquid such as physiological saline is injected by a syringe 400 into a transparent tube 102 installed vertically on the stage 101.

The stage 101 is constructed so that its position is finely adjusted three-dimensionally by an X-Y axis stage driving device 107 and a Z axis stage driving device 108, and the stage 101 is within the field of view of the objective lenses 103 _{1 to} 103 _3. The sample is designed to be captured.

The transparent tube 102 is the objective lens 103 _1.
To 103 a triangular prism constituted by three surfaces perpendicular to the _third optical axis, influence of aberration by the configuration of the transparent tube is adapted to be reduced. Further, focusing surface drive devices 105 _{1 to} 105
_The image processing processor 200 controls the ₃ -axis and XY axis stage driving device 107 and the Z-axis stage driving device 108.

Next, the structure of the image processor 200 will be described. The CPU 201 is the image processor 20.
Although the operation control of the entire 0 is performed, a command signal is also sent to the stage drive device driver 202 and the focusing surface drive device driver 203, and mechanical drive control of the microscope device 100 is also performed. Electrical image signal from the TV camera 106 _{1-106 3} is converted by the A / D converter 204 _{1-204 3} to predetermined digital image signal is recorded in the image memory 205 _{1-205 3.} This operation is performed each time the focusing surface of each microscope is moved by the focusing surface driving devices 105 _{1 to} 105 _{3 in the} optical axis direction at a predetermined interval, and images for a plurality of different focusing surfaces are stored in the image memory 205 _1. ~ 20
All will be recorded in 5 ₃ .

[0045] ROM206, the (3) pseudo-inverse matrix shown in formula (HH ^{t) -} and inverse transform operator H ^t {and coefficients are the records of}, is called the coefficient corresponding to a predetermined condition from the CPU201 It is sent to the accelerator 207. The accelerator 207 is composed of a vector processor that performs a large-scale matrix operation at high speed by pipeline processing and the like, and an internal memory. Accelerator 207
Then, the matrix operation based on the equation (3) is executed between the predetermined one-dimensional profile signal read from the image memories 205 _{1 to} 205 ₃ and the coefficient sent from the ROM 206. The estimated tomographic image thus obtained is resampled to an appropriate size for display, then transferred to the frame memory 208, converted into a predetermined analog video signal by the D / A converter 209, and then the TV monitor 3
00 is displayed. The input digital image signal and the reconstructed tomographic image to be stored are recorded in the built-in disk device 210.

With respect to the above processing, input / output of digital signals between respective constituent elements is performed via the internal bus 211. A user interface 213 including a display and a keyboard / mouse is connected to the CPU 201 via a user interface interface 212, and the values of various parameters and operating conditions are displayed on the display, and the operation is performed at the same time. A command signal from a person is transmitted to the CPU 201.

The operation of the structure of the first embodiment described above will be described below. The first embodiment is to reconstruct a tomographic image of the sample in the transparent tube 102 using the images input while moving the focal plane position from three directions, and its operation is the same as that of the above-described embodiment. It is based. The definition of the pseudo inverse matrix based on the image input method according to the first embodiment will be described below. First, the image input system when the optical axis is fixed and the focusing surface is set to the k-th object surface is represented as follows.

G _k = H _k {f (r)} (12) g _k is a vector composed of M image pickup elements. Next, consider a system in which the focusing surface is discretely moved at a predetermined interval while the optical axis is fixed, and L images are input. In this case, equation (12) is defined by the number of in-focus surfaces, but (k =
1, 2, ..., L), a new observation image g ⁰ is defined by arranging the obtained observation images in one column. In this case, g
⁰ is composed of M × L elements.

[0049]

[Equation 7]

Next, let us consider a system for inputting an image under the same conditions as in the equation (14) in the directions in which the optical axes differ by 120 °. The observed image g ¹ obtained in this case is defined as follows.

G ¹ = H ¹ {f (r)} (15) The operator H ¹ {} is equivalent to rotating the sample relatively by −120 ° and causing H ⁰ {} of the equation (13) to act. It can be thought of as an operator, so the continuous object is -1
When the operator R ₋₁₂₀ {} that rotates by 20 ° is defined, the equation (15) can be expressed as follows.

G ¹ = H ⁰ [R ₋₁₂₀ {f (r)} (16) Since both operators H ⁰ {} and R ₋₁₂₀ {} are based on linear operation, equations (15) and (16) are used. , Can be defined matrixwise as follows.

H ¹ {} = H ⁰ R ₋₁₂₀ {} (17) Similarly, the image input system is defined as follows in the direction in which the optical axes are relatively different by 240 °.

G ² = H ² {f (r)} = H ⁰ R ⁻²⁴⁰ {f (r)} (18) By arranging the observation images g ⁰ , g ¹ , g ² defined as above, The image input system from three directions is written as follows.

[0055]

[Equation 8]

The finally defined observation image is M × L × 3.
It is a vector consisting of individual elements. The operator H {} defined by the equation (19) is used to reconstruct the tomographic image based on the equation (3).

According to the first embodiment described above, the N. A. It is possible to reconstruct a tomographic image excellent in resolution in any direction by using the microscope with the objective lens of No. 2 by using the image input under the necessary minimum conditions.

Although the present embodiment has been described as reconstructing a two-dimensional tomographic image from a one-dimensional line profile in an input image, a three-dimensional image is reconstructed by directly processing the input two-dimensional image. It may be done. In that case, a voxel processor for outputting and displaying as a two-dimensional image by performing a predetermined process on the three-dimensional image is provided in the image processor 200.

The second embodiment of the present invention will be described below. FIG. 3 shows the configuration of the microscope apparatus 500 according to the second embodiment of the present invention. The configurations of the image processor 200 and the TV monitor 300 in the second embodiment are the same as those in the first embodiment. The sample is held by the sample holder 510 in the microscope apparatus 500, and the sample is driven and controlled by the sample rotation driving device 520. The microscope optical system is an objective lens 530.
And a lens barrel 540. Objective lens 530
Is driven by the focusing surface drive device 550 in the optical axis direction to move the focusing surface. The lens barrel 540 is a surface perpendicular to the optical axis by the lens barrel driving device 560. It is configured such that the position is finely adjusted inside.

The formed image of the sample is picked up by the TV camera 570 and sent to the A / D converter 204 in the image processor 200. The sample rotation driving device 520, the focusing surface driving device 550, and the lens barrel driving device 560 having the above-described configuration.
Are both controlled by the CPU 201 in the image processor 200.

FIG. 4 is a diagram showing the structure around the stage. The sample holder 510 is a transparent tube 511 into which a sample is injected.
And a transparent tube supporting base 512 ₁ for supporting the transparent tube 511.
And 512 ₂ . The sample rotation driving device 520 is
It is configured by a motor 521, a pulley 522, and a belt 523, and is configured to control the rotation of the transparent tube 511.

The operation of the second embodiment having the above construction will be described below. According to the second embodiment, the relative angle of the optical axis with respect to the sample can be set arbitrarily. Therefore, the objective lens 53
0 to replace N. A. The number of directions can be optimized in the case where is changed. Further, for example, N. A. = 0.5
In the case of, the missing region on the spatial frequency can be filled by inputting from three directions as described above, but this is the minimum necessary condition, and the spatial frequency for an arbitrary angular direction can be increased by further increasing the number of directions. You can also enhance the characteristics.

According to the second embodiment described above, a device having a wide range of application can be constructed in a relatively compact size according to the purpose. The third embodiment of the present invention will be described below.

FIG. 5 shows the structure of a microscope apparatus 600 according to the third embodiment of the present invention. The configurations of the image processor 200 and the TV monitor 300 in the third embodiment are the first.
It is similar to the embodiment. The microscope apparatus 600 is such that the focusing surface drive unit 550 is removed from the microscope apparatus 500 in the second embodiment and an aperture control unit 650 is provided instead.

FIG. 6 shows the aperture controller of the objective lens 630. The objective lens 630 is composed of a plurality of lens groups, and diaphragm blades 631 _{1 to} 631 _n (n ≦
10) is provided, and these are driven in the rotation direction, so that the N.V. A. Are configured to change. Such a diaphragm mechanism is driven and controlled by a motor 651 in the aperture controller 650, and the motor 651 is driven by a motor driver 652 controlled by a command signal from the CPU 201 in the image processing processor 200.

With the above configuration, the following image input operation is executed. When a certain optical axis direction is set for the sample, a different N.V. A. By this, a plurality of images are input. This operation is repeated several times to several tens times while relatively changing the optical axis direction by rotating the sample discretely at a predetermined angular interval. A tomographic image is reconstructed by the image reconstruction method according to the present embodiment using the image thus input.

The operation of the third embodiment having the above construction will be described below. In the third embodiment, an image is input using only the rotation of the optical axis without driving the focusing surface. In this case, the image near the rotation center of the optical axis can be densely input in the object space, but becomes sparse as the distance from the rotation center increases. Therefore, the resolution of the reconstructed image is expected to deteriorate as the distance from the rotation center increases. In order to correct such an influence, in this embodiment, the N.M. A. A means for changing the input and inputting an image is provided.

Generally, the N.V. A. When is large, the resolution is excellent and the depth of focus becomes shallow. Conversely, N. A. When is smaller, the resolution is degraded but the depth of focus is deeper.
In the third embodiment, N. A. Is used to complementarily utilize the optical characteristics of the both, and has the effect of reconstructing a tomographic image with excellent resolution in a wider range of the object space. According to the reconstruction method of the third embodiment, N. A. It is possible to reflect the characteristics of both large and small cases in the reconstructed image, so that the above-described operation becomes possible.

According to the third embodiment described above, since the focusing surface is not driven, the mechanical position control is limited to only the rotation of the sample, the accuracy of position alignment is improved, and errors due to mechanical factors are eliminated. Can be reduced.

[0070]

As described above, according to the optical image reconstructing apparatus of the present invention, it is possible to reconstruct an optical tomographic image or an optical three-dimensional image excellent in resolution in an arbitrary angle direction from the minimum necessary image input conditions. A practically useful optical image reconstruction device can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a configuration around a sample in the microscope apparatus of FIG.

FIG. 3 is a diagram showing a configuration of a microscope apparatus according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a configuration around a stage.

FIG. 5 is a diagram showing a configuration of a microscope apparatus according to a third embodiment of the present invention.

FIG. 6 is a diagram showing an aperture control unit of an objective lens.

FIG. 7 shows 3-dimensional spatial frequency characteristics of a fluorescence microscope 3-
It is a conceptual diagram of dOTF.

FIG. 8 is a diagram showing a 3-dOTF in the form of a microscope capable of inputting an image without missing in any direction.

FIG. 9 is a diagram for explaining the setting of each focusing surface interval on the assumption that an image is input while moving the focusing surface of the optical imaging system in the optical axis direction.

FIG. 10 is a conceptual diagram of an image forming system of an optical microscope.

FIG. 11 is a configuration diagram of a conventional general microscope.

[Explanation of symbols]

100 ... Microscope device, 101 ... Stage, 102 ... Transparent tube, 103 ... Objective lens, 104 ... Lens barrel, 105 ... Focusing surface drive device, 106 ... TV camera, 200 ... Image processing processor, 201 ... CPU, 202 ... Stage Driving device driver, 203 ... Focusing surface driving device driver, 204 ...
A / D, 205 ... Image memory, 206 ... ROM, 207
... accelerator, 208 ... frame memory, 209 ...
D / A, 210 ... Built-in disk device, 211 ... Internal bus, 212 ... User interface interface, 213 ... User interface, 300 ... TV monitor.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-3-12524 (JP, A) JP-A-5-306993 (JP, A) JP-A-5-223738 (JP, A) JP-A-4- 122248 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G06T 1/00 295 G06T 1/00 420 G06T 1/00 500 G01N 21/27 620 G02B 21/22

Claims (3)

(57) [Claims] 1. The same numerical aperture (Numerical Aperture) radially arranged so that the optical axes intersect at a predetermined point in the object space.
ture, hereinafter N. A. ), An image pickup means for converting an image of the object formed by each of the N optical image formation systems into an electric image signal, and an image pickup means for picking up the image. An image memory for storing N electrical image signals, and a tomographic image of an object parallel to the optical axis of the optical imaging system, using the N electrical image signals stored in the image memory. In the optical image reconstructing device having a tomographic image reconstructing unit for reconstructing, the number N of the optical imaging systems is an angle α (however,
The optical imaging system N. A. Is n sin α, and n is the refractive index
To N) = 180 ° / (2α)
An optical image reconstructing device, characterized in that the optical image reconstructing devices are evenly arranged in a direction . 2. An optical imaging system capable of arbitrarily setting a relative angle of an optical axis with respect to an object, and an image of the object imaged by said optical imaging system, An image pickup unit that converts into an electric image signal N times while relatively changing the optical axis direction, an image memory that stores N electric image signals picked up by the image pickup unit, and the image memory And a tomographic image reconstructing means for reconstructing a tomographic image of an object parallel to the optical axis of the optical imaging system by using the N electrical image signals that have been recorded. The set number N in the optical axis direction of the optical imaging system is the angle α (only
The numerical aperture N.V. of the optical imaging system. A. (Numerical Aper
(ture) is n sin α, and n is the refractive index), N
= 180 ° / (2α), set at equal intervals in the angular direction
By optical image reconstruction apparatus according to claim Rukoto. 3. The tomographic image reconstructing means includes the electrical image signal stored in the image memory.
Equipped with a matrix calculator that performs linear calculations with a predetermined matrix
However, the predetermined matrix corresponds to each image pickup element in the image pickup means.
On the object space transmitted by the optical imaging system to the child
A sensitivity distribution function that represents the light intensity distribution at is defined, and the image input system determined by the optical imaging system and the imaging unit is defined as the sensitivity distribution function.
Is a generalized inverse matrix defined linearly using a function
Claim 1 or claim 2 characterized in that
Optical image reconstruction device.