JPH10132519A - Light transmission image device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the unevenness of sensibility at every position due to the irregularity of the surface of a detected body. SOLUTION: A thin optical beam is radiated from a laser beam irradiating device 10 toward a detected body 71, and the then transmitted beam is made incident on a solid image pickup element 12 through a multifiber optical element 23 which has a surface-shape suited to the irregularity of the surface of the detected body 71 and is stuck fast to the surface of the detected body 71 and a convex lens, and the optical beam is scanned to take out only a picture element data corresponding to a scanned position among image data for one sheet obtained from the solid image pickup element 12 at every scanned position for creating the image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light transmission imaging apparatus suitable for use in medical image diagnosis, scientific and engineering inspections, and inspection of foods and the like.

[0002]

2. Description of the Related Art As a device that transmits light to a subject and captures an image of the transmitted light, there is known a device that scans a subject with a thin laser beam to obtain an image (Japanese Patent Laid-Open No. 6-2).
No. 78028, “Multi-laser light scanning biopsy diagnosis and treatment device”).

[0003]

However, the conventional apparatus has a problem that it is not possible to obtain highly accurate data when the surface of the subject has irregularities.
For example, when the subject is a part such as a human hand, a base of a toe, a heel, or the like, a large gap between the surface of the subject and the optical system because the surface is a curved surface having irregularities. It is inevitable that light transmitted or scattered through the subject is incident on the imaging device via the optical system, and in the process of escaping, the light largely escapes to the outside in the gap and the imaging device , The amount of light incident on the corresponding pixel decreases, and the data of the corresponding pixel deteriorates significantly.

[0004] In view of the above, it is an object of the present invention to provide a light transmissive imaging apparatus improved so that highly accurate image data can be obtained even when the surface of the subject has irregularities.

[0005]

In order to achieve the above object, in a light transmission imaging apparatus according to the present invention, a light generating means for generating a thin light beam, and the light beam is two-dimensionally applied to a subject. Scanning means for performing parallel scanning on the object, image transmission means having a multi-fiber structure having a surface shape substantially along the surface shape of the subject, imaging means for inputting an image transmitted by the image transmission means, and imaging A means for extracting a signal of a portion substantially corresponding to the scanning position of the output image signal of the means to form an image.

When an object is irradiated with a light beam, transmitted light or scattered light emerges from the object. The transmitted light and the scattered light are guided to the imaging means via the image transmission means having a multi-fiber structure, and the surface shape of the image transmission means is made to substantially conform to the surface shape of the subject. Therefore, the surface of the image transmitting means can be brought into close contact with the surface of the subject to reduce the gap therebetween, and the rate at which transmitted light or scattered light coming out of the subject escapes so as to spread outside can be significantly reduced. A sufficient amount of light can be guided to the imaging unit. Therefore, highly sensitive light detection becomes possible, and highly accurate image data can be obtained. This light beam is two-dimensionally scanned in parallel, and one image signal is obtained from the above-mentioned imaging means at each position of the scanning.
A signal of a portion substantially corresponding to the scanning position is extracted from the one image signal, and this is repeated for each scanning position to create one image. Then, in the created image, the data of each pixel is mainly composed of the transmitted light component that has transmitted linearly through the subject, and even if a scattered light component is included, the data is scattered and spread very close to the subject. Since only the near scattered light component due to the scattered light is used, the accuracy is high.

[0007]

Next, embodiments of the present invention will be described in detail with reference to the drawings. In the present invention, as shown in FIG. 1, a light beam is emitted from a laser light irradiation device 10 toward an object 71, and light transmitted through the object 71 is passed through a multi-fiber optical element 23 to form a convex lens 11 for focusing. , And the image is reduced by the convex lens 11 and transmitted to a solid-state imaging device (comprising a CCD or the like) 12. The light beam is moved while the irradiation direction is kept parallel, and parallel scanning of the light beam is performed. The multi-fiber optical element 23 has a structure in which a large number of optical fibers are bundled and integrated, and the position of each optical fiber is made to correspond on the input side and the output side. The image is output while being kept, that is, the input image is output as it is. Here, the surface is formed according to the surface shape of the subject 71.
In other words, for example, if it is used mainly for imaging human hands, toes, heels, etc., the shape is adapted to them.
Prepare various types for hands, feet, heels, etc.

Therefore, the surface of the subject 71 and the surface of the multi-fiber optical element 23 are almost in close contact with each other, and light penetrating the subject 71 is transmitted to the convex lens 11 as it is without spreading, and is guided to the solid-state imaging device 12. As a result, the rate at which light emitted from the subject 71 escapes to the outside is significantly reduced, and almost all light can be guided to the solid-state imaging device 12, so that sensitivity is increased, image data is prevented from deteriorating, and data The accuracy can be improved.

FIG. 2 shows the overall configuration, in which the laser beam irradiation device 10, the multi-fiber optical element 23, the convex lens 11, the solid-state image sensor 12, and the like are housed in a dark box 72 or the like, whereby the subject A space in which 71 is arranged is formed in the dark box 72, and is configured such that noise light from the outside does not enter the solid-state imaging device 13.

The solid-state image pickup device 1 is read by the readout circuit 13.
The image signal read out from 2 is temporarily stored in the image acquisition memory 14 and then read out and transferred to the image processing memory 17 via the interface circuits 15 and 16.
This image data undergoes processing such as editing and image calculation by the CPU 18 to create an image. This image is displayed on the display device 21. The CPU 18 controls the acquisition control circuit 20 via the interface circuit 19, and the acquisition control circuit 20 sends a command to the laser beam irradiation device 10 to control the scanning of the light beam and sends a command to the image acquisition memory 14. Control this. An input device such as a keyboard is connected to the CPU 18 so that commands and various information can be input.

The laser beam irradiation device 10 is, for example, shown in FIG.
And two-dimensionally parallel scanning one of the three wavelength laser light beams. That is, here, three laser light sources 31, 32, and 33 that generate laser beams of different wavelengths are provided, and one of them is selectively operated by the selection switch circuit 61 controlled by the collection control circuit 20. Can be Three laser light sources 3
1, 32 and 33 each have a lens (concave lens etc.)
The lenses 41, 42, and 43 form laser beams generated from the light sources 31, 32, and 33 into narrow parallel light beams. This light beam is applied to a plane mirror 51,
The light beam reflected by the object is irradiated on the subject 71 side.

The laser light sources 31, 32, 33 and the lenses 41, 42, 43 are integrally held and moved in the X direction by an X direction drive circuit 62. The plane mirror 51 is moved in the Y direction by a Y direction drive circuit 63. The X-direction drive circuit 62 and the Y-direction drive circuit 63 are controlled by the collection control circuit 20, and the light beam is scanned in parallel on the XY plane. The laser light source 3
1, 32, and 33 and the lenses 41, 42, and 43 are separately configured for each wavelength, so that the position of the light beam of each wavelength is different. The position in the Y direction is adjusted.

This laser beam irradiation device 10 can also be configured as shown in FIG. In FIG. 4, the movement of the light beam in the X direction depends on the movement of another plane mirror 52 in the X direction. That is, light beams of respective wavelengths are emitted in the X direction from the laser light sources 31, 32, 33 and the lenses 41, 42, 43, and the plane mirror 52 is moved in the light beam direction (X direction) by the X direction driving circuit 62. The light beam incident on the plane mirror 51 is moved in the X direction. Other configurations are the same as those in FIG.

The cross-sectional area of the light beam irradiated toward the subject 71 is made to correspond to one pixel size and to be equal to or slightly larger than that, or to a fixed number (2 × 2, 4 × 4).
, Etc.), and the same or slightly smaller size. When the cross-sectional area of the light beam is equal to the size of one pixel, the light beam is scanned and stopped for a certain period of time at each pixel position before scanning. If the cross-sectional area of the light beam is made to correspond to the size of a fixed number of pixels such as 2 × 2, 4 × 4, etc., the light beam is sequentially stopped for a certain time at each position of the number of pixels when scanning the light beam. And irradiate.

When the cross-sectional area of the light beam is made equal to the size of one pixel, FIG.
(A), (b), (c)... Are read out from the solid-state imaging device 12 and stored in the image collection memory 14. Here, the matrix of the image (which may be considered as the physical matrix of the solid-state imaging device 13) is assumed to be 4 × 4 for convenience of description, and the scanning is performed from the upper left to the right. When the position of the light beam is at the upper left pixel position, an image as shown in FIG.
The data of the pixel at that position is a transmitted light component that has transmitted linearly through the subject 71, and the data of the surrounding pixels is a scattered light component that has been scattered and spread near the bend. Each time image data obtained for each position is stored in the image acquisition memory 14, it is immediately read out and transferred to the image processing memory 17, and only the data of the pixel at the light beam position is extracted. This is repeated for each position in the light beam scanning to create an image as shown in FIG. Since this image is made by collecting only the transmitted light components that have transmitted linearly through the subject 71 in this way, the data of each pixel contains almost no scattered light components, and is extremely accurate. It will be expensive.

When the cross-sectional area of the light beam is made to correspond to the size of 2 × 2 pixels, the solid-state image pickup device 12 sequentially outputs the light beam scanning positions from the solid-state image pickup device 12 as shown in FIGS. c) ...
Is read out and stored in the image collection memory 14. Here, the image matrix is set to 8 × 8, scans from the upper left to the right, moves two distances and stops, and when it reaches the right end, it moves down by two and moves left by two. And

Also in this case, when the position of the light beam is at the upper left position, an image as shown in FIG. 6A is obtained.
In this image, the data of the four (2 × 2) pixels at the light beam position is the transmitted light component that has transmitted linearly through the subject 71, and the data of the surrounding pixels is scattered and the vicinity of the bend. The scattered light component spreads out. Only the data of the above four pixels are extracted from this image. Such an operation is repeated for each scanning position to create one image as shown in FIG. Since this created image is created by collecting only the transmitted light components that have transmitted linearly through the subject 71, the data of each pixel hardly contains the scattered light components, and is extremely accurate. . By making the matrix of the light beam scanning position coarser than the matrix of the image,
The overall scanning time can be reduced while obtaining a high-definition image.

When the cross-sectional area of the light beam is slightly smaller than the size of a 2 × 2 pixel, the data of each pixel includes not only the transmitted light component that has transmitted linearly through the subject 71, but also
Although it also includes a scattered light component, since it is scattered and spread very close, it is not a scattered light component from a distant place, but maintains a certain accuracy.

By sequentially switching and scanning the laser light sources 31, 32 and 33, three types of such images are created. Let each wavelength of the light beam be λ1, λ2, λ
Assuming that 3, the absorbance A1, A2, A3 of the pixel or the time variation ΔA1, ΔA2, ΔA3 of the pixel is obtained from the data of each pixel or the time variation of the data for each image using the following principle. . Then, for each pixel, it is possible to obtain a concentration parameter of a specific component contained in the subject 71 or a time change amount thereof by performing arithmetic processing using the absorbance of each wavelength or the change amount of the absorbance for each pixel. By performing this calculation for each pixel, the distribution (two-dimensional image) of the density parameter or its time change amount is obtained.

For light of a certain wavelength λj (j = 1, 2, or 3), the incident light intensity is Ij0, and the data of a certain pixel obtained by measuring around a certain time t, that is, the transmitted light intensity is represented by Ijt. Suppose. The subject is a uniform light absorber, the thickness of the absorber is L, and two types of light absorbing material a
Considering the case where the respective concentrations at time t are Cat and Cbt as an example, Lambe
According to rt-Beer's law, the following Expression 1 is established.

(Equation 1) Here, μjt is the absorption coefficient at time t Ajt is the absorbance at time t εaj and εbj represent the absorption coefficients of substances a and b, respectively.

When the data of the pixel measured at around time t ′ = t + Δt, that is, the transmitted light intensity is represented by Ijt ′, the absorbance Ajt ′ is similarly represented by the following equation (2).

(Equation 2) Therefore, the change amount Δ of the absorbance from time t to time t ′
Aj is given by the following equation (3), assuming that Ij0 is constant.

(Equation 3) Is represented by Here, ΔCa = Cat′−Cat and ΔCb = Cbt′−Cbt represent the amounts of change in the concentrations of the substances a and b, respectively.

The same applies to the case where the number of light absorbing substances is not two. When scattering exists in addition to absorption, Ajt
And Ajt 'are called dimming degrees, and it is necessary to consider not only the absorption coefficient but also the scattering coefficient, but they are similar in principle.

For example, λ1 = 780 nm, λ2 = 80
When 5 nm and λ3 = 830 nm, oxygenated components oxy (Hb + M) of hemoglobin and myoglobin
b), each time change amount Δoxy (Hb + Mb) of the deoxygenated component deoxy (Hb + Mb), Δdeoxy (H
b + Mb) are approximately represented by the following equations. Δoxy (Hb + Mb) = − 3.0ΔA2 + 3.0ΔA
3 Δdeoxy (Hb + Mb) = 1.6ΔA1-2.8Δ
A2 + 1.2ΔA3 Then, by performing these calculations, oxy (H
b + Mb) and time change Δoxy (Hb + Mb) of deoxy (Hb + Mb), Δdeoxy (Hb + Mb)
Can be obtained.

The above is a description of one example, and various modifications can be made without departing from the spirit of the present invention. For example, the laser light irradiation device 10
Is not limited to the configuration shown in FIGS. 3 and 4, but may be any as long as it can scan the irradiated light beam in parallel in one plane (for example, the XY plane). For this reason, for example, it is conceivable to move the block itself in which the laser light sources 31, 32, 33 and the lenses 41, 42, 43 are integrally formed in the X and Y directions. In addition, the laser light sources in a one-dimensional array may be moved, or a laser light source in a two-dimensional array may be used. In these cases, the laser light sources are sequentially turned on. The mechanism for scanning the light beam is not limited to the mechanism for moving the plane mirror, and various mechanisms can be adopted, and optical means such as an optical switch can be used. Although three wavelengths were used, one wavelength, two wavelengths, or four or more wavelengths may be used. The wavelength can be switched by using an optical means such as an optical switch.

Further, instead of the convex lens 11, any optical element having a characteristic of reducing and transmitting an image, such as an optical element (image fiber) having a multi-fiber structure formed by bundling a large number of optical fibers and forming a tapered shape, is used. , And others can be used. If such a multi-fiber optical element is used in place of the convex lens, it is formed integrally with the multi-fiber optical element 23 that is in close contact with the subject 71 (in fact, a multi-fiber optical element instead of the convex lens). Adjusting the surface shape to the surface shape of the subject 71 is also conceivable.

[0026]

As described above, according to the light transmission imaging apparatus of the present invention, even when the surface of the object has irregularities, the multi-fiber optical element having the corresponding irregularities is applied to the object. The surface of a subject having irregularities can be brought into close contact with the input side of the multi-fiber optical element, so that light coming out of the subject can be guided to the image sensor without escaping to the outside, and Irregularity in sensitivity (position dependency of sensitivity) at each position due to unevenness can be remarkably improved, image data with high accuracy can be obtained, and image quality can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is a schematic view showing the whole of the embodiment.

FIG. 3 is a schematic view illustrating an example of a laser light irradiation device.

FIG. 4 is a schematic view showing another example of the laser light irradiation device.

FIG. 5 is a diagram illustrating an example of an image matrix.

FIG. 6 is a diagram illustrating another example of an image matrix.

[Explanation of symbols]

REFERENCE SIGNS LIST 10 laser light irradiation device 11 focusing lens (convex lens) 12 solid-state imaging device 13 readout circuit 14 image collection memory 15, 16, 19 interface circuit 17 image processing memory 18 CPU 20 collection control device 21 display device 22 input device 23 multi-fiber optics Element 71 Subject 72 Dark box 31, 32, 33 Laser light source 41, 42, 43 Parallel light forming lens 51, 52 Planar mirror 61 Selection switch circuit 62 X direction drive circuit 63 Y direction drive circuit

Continued on the front page (72) Inventor Yoshio Tsunazawa 380-1 Matsuba, Horiyamashita, Hadano-shi, Kanagawa Prefecture Inside the Hadano Plant, Shimadzu Corporation (72) Inventor Hiroaki Kumagai 4-7-10 Minami Tsukushino, Machida-shi, Tokyo

Claims (1)

[Claims] A light generating means for generating a thin light beam;
Scanning means for two-dimensionally scanning the light beam parallel to the object, image transmission means having a multi-fiber structure having a surface shape substantially along the surface shape of the object, and transmission by the image transmission means Imaging means to which the image is input,
Means for extracting a signal of a portion of the output image signal of the imaging means substantially corresponding to the scanning position and creating an image.