JP4746482B2 - Tomographic image generating apparatus, tomographic image generating method, and tomographic image generating program - Google Patents

Description

  The present invention relates to a tomographic plane image generation apparatus, a tomographic plane image generation method, and a tomographic plane image generation program.

Conventionally, dental panoramic tomography apparatuses are known (see, for example, Patent Document 1 and Patent Document 2). In the conventional apparatus, it is assumed that a predetermined standard dentition position is used as a reference, and a tomographic image at that position is acquired.
JP-A-10-2111200 (0033-0040, FIG. 4) Japanese Utility Model Publication No. 4-48169 (pages 3 to 4 and FIG. 4)

  In the conventional apparatus, it is assumed that a predetermined standard dentition position is used as a reference, and a tomographic image at that position is acquired. There is a problem in that an optimum tomographic image cannot be acquired if the position of the dentition is not suitable. That is, an image of a tomographic plane in which the subject's dentition is in focus could not be acquired. Moreover, in the conventional apparatus, the operation | work which matches the optimal tomographic plane was performed manually.

  Accordingly, the present invention provides a tomographic plane image generation device, a tomographic plane image generation method, and a tomographic plane image generation program capable of solving the above-described problems and automatically acquiring an optimal tomographic plane image of a subject. For the purpose.

  In order to solve the above-described problem, the tomographic plane image generation device according to claim 1 includes an X-ray source that irradiates a subject with X-rays and an imaging unit that receives X-rays transmitted through the subject with a predetermined rotation center. A plurality of predetermined tomographic planes formed by superimposing a plurality of pieces of X-ray image information of the subject imaged by a panoramic tomography apparatus that rotates and slides around to photograph the subject. A tomographic plane image generation apparatus that resets a tomographic plane of the subject using the tomographic plane image information and generates an image of the reset tomographic plane, wherein a plurality of predetermined planes for the subject are determined. Spectral information generating means for generating a plurality of spectrum information, which is information obtained by frequency-converting a plurality of tomographic plane image information corresponding to a tomographic plane, and the generated plurality of spectrum information Therefore, for each predetermined position of the subject, high-frequency region extracting means for extracting position information of a high-frequency region that is a region having the highest value of the high-frequency component among the plurality of tomographic plane image information, and the subject about the subject Model generating means for generating a multi-fault model that is a model in which position information of a plurality of predetermined tomographic planes and position information of the high-frequency region extracted for each predetermined position of the subject are associated with each other; In the multi-tomographic model, the tomographic plane is reset by connecting the high-frequency regions extracted for each predetermined position of the subject, and the position of the high-frequency region and the rotation center are determined for each position information of the high-frequency region. A tomographic plane resetting means for obtaining the overlap width of the X-ray image information from the distance, and the X-ray image information corresponding to a predetermined position of the subject Image information synthesizing means for generating an image of the reset tomographic plane by synthesizing with the overlap width of the X-ray image information obtained with respect to the reset tomographic plane. To do.

  According to such a configuration, the tomographic image generating apparatus frequency-converts image information corresponding to the tomographic plane of the subject by the spectrum information generating unit. Here, as the frequency conversion method, for example, FFT, wavelet conversion, filter convolution processing, or the like can be used. Then, the tomographic plane image generation device extracts the high frequency region based on the spectrum information obtained by the frequency conversion by the high frequency region extraction means. This high frequency region corresponds to the best focus position in the tomographic plane image. Then, the tomographic plane image generating device generates a multi-fault model in which the position information of the high-frequency region is associated with each tomographic plane by the model generating unit, and the tomographic plane on the multi-fault model by the tomographic plane resetting unit. Reset it. When resetting, a new fault plane is constructed by interpolation. Here, spline conversion or average value interpolation can be used as the interpolation method. Then, the tomographic plane image generation device synthesizes the image on the constructed tomographic plane by the image information synthesis unit.

According to a second aspect of the present invention, there is provided the tomographic plane image generation apparatus according to the first aspect, wherein the X-ray source irradiates a vertical X-ray fan beam and the image information The synthesizing unit includes a vertical direction correcting unit that performs correction for enlarging the reset image of the tomographic plane in the vertical direction at an enlargement ratio P shown in Expression (1), and the image of the reset tomographic plane. And a horizontal direction correction unit that performs correction to enlarge in the horizontal direction at an enlargement ratio H shown in Formula (2).
P = (a−L) / a (1)
H = r × (a−L) / {a × (r−L)} (2)
Here, a represents the distance between the X-ray source and the predetermined position of the tomographic plane on a straight line connecting the X-ray source and the imaging means, and L represents the predetermined of the subject on the straight line. A deviation from the position of the obtained tomographic plane is indicated, and r indicates a distance between the rotation center and the predetermined position of the tomographic plane on the straight line.

  According to such a configuration, the tomographic plane image generation device automatically corrects the vertical size of the tomographic plane image by the vertical direction correction unit, and at the same time the horizontal direction of the tomographic plane image by the horizontal direction correction unit. Can be automatically corrected.

  Further, in order to solve the above problem, the tomographic image generation method according to claim 3 includes a predetermined rotation of an X-ray source that irradiates a subject with X-rays and an imaging unit that receives X-rays transmitted through the subject. Corresponding to a plurality of predetermined tomographic planes formed by superimposing a plurality of pieces of X-ray image information of the subject imaged by a panoramic tomography apparatus that images the subject by rotating and sliding around the center. A method for generating a tomographic plane image of a tomographic plane image generation apparatus, which uses a plurality of pieces of tomographic plane image information to reset a tomographic plane of the subject and generates an image of the reset tomographic plane. The surface image generation device generates a plurality of spectrum information that is information obtained by frequency-converting a plurality of tomographic plane image information corresponding to a plurality of predetermined tomographic planes for the subject. Information generation step and, based on the generated plurality of spectrum information, for each predetermined position of the subject, position information of a high-frequency region that is a region having the highest value of the high-frequency component among the plurality of tomographic plane image information A high frequency region extracting step for extracting a plurality of predetermined tomographic plane position information for the subject, and position information of the high frequency region extracted for each predetermined position of the subject. A model generation step of generating a multi-fault model, and reconfiguring a tomographic plane by connecting the high-frequency regions extracted for each predetermined position of the subject in the multi-fault model, and position information of the high-frequency regions Every time, the overlap width of the X-ray image information is determined from the distance between the position of the high-frequency region and the rotation center. Combining the X-ray image information corresponding to the predetermined position of the subject with the overlap width of the X-ray image information obtained with respect to the reset tomographic plane. And an image information synthesis step for generating an image of the tomographic plane.

  According to such a procedure, the tomographic plane image generation device frequency-converts image information corresponding to the tomographic plane of the subject in the spectral information generation step, and based on the spectral information obtained by frequency conversion in the high-frequency region extraction step, Extract high frequency region. Then, the tomographic plane image generation device generates a multi-fault model in which each tomographic plane is associated with positional information of a high-frequency region in the model generation step, and in the tomographic plane resetting step, the tomographic plane is generated on the multi-fault model. Reset it. Then, the tomographic plane image generation apparatus synthesizes the image on the reset tomographic plane in the image information synthesis step.

According to a fourth aspect of the present invention, there is provided the tomographic image generation method according to the third aspect, wherein the X-ray source irradiates an X-ray fan beam spread in a vertical direction to generate the image information. The compositing step includes a vertical direction correcting step for correcting the reset tomographic plane image in the vertical direction at an enlargement ratio P shown in Expression (1), and the reset tomographic plane image. And a horizontal direction correction step for performing a correction to enlarge in the horizontal direction at an enlargement ratio H shown in Expression (2).
P = (a−L) / a (1)
H = r × (a−L) / {a × (r−L)} (2)
Here, a represents the distance between the X-ray source and the predetermined position of the tomographic plane on a straight line connecting the X-ray source and the imaging means, and L represents the predetermined of the subject on the straight line. A deviation from the position of the obtained tomographic plane is indicated, and r indicates a distance between the rotation center and the predetermined position of the tomographic plane on the straight line.

  According to such a procedure, the tomographic plane image generation apparatus automatically corrects the vertical size of the tomographic plane image in the vertical direction correction step, and at the horizontal direction correction step, the horizontal direction of the tomographic plane image. Automatically correct the size of. Note that the execution order of the correction in the vertical direction and the correction in the horizontal direction is arbitrary, and may be executed in parallel.

  The tomographic plane image generation program according to claim 5 rotates and slides an X-ray source for irradiating a subject with X-rays and an imaging means for receiving X-rays transmitted through the subject around a predetermined rotation center. A plurality of tomographic plane image information corresponding to a plurality of predetermined tomographic planes formed by superimposing a plurality of pieces of X-ray image information of the subject imaged by a panoramic tomography apparatus that images the subject. In order to reset the tomographic plane of the subject and generate an image of the reset tomographic plane, the computer uses a plurality of tomograms corresponding to a plurality of predetermined tomographic planes for the subject. Spectral information generation means for generating a plurality of spectrum information that is information obtained by frequency-converting the surface image information, respectively, based on the generated plurality of spectrum information, A high-frequency region extracting means for extracting position information of a high-frequency region that is a region having the highest value of the high-frequency component among the plurality of tomographic plane image information, and the predetermined plurality of predetermined values for the subject Model generation means for generating a multi-fault model that is a model in which position information of a tomographic plane and position information of the high-frequency region extracted for each predetermined position of the subject are associated with each other; The tomographic plane is reset by connecting the high-frequency regions extracted for each predetermined position, and the X-ray image is calculated from the distance between the position of the high-frequency region and the rotation center for each position information of the high-frequency region. A tomographic plane resetting means for determining the overlapping width of the information, and the X-ray image information corresponding to a predetermined position of the subject By combining with superposition width of the X-ray image information obtained with respect to, characterized in that to function as an image information combining means for generating a tomographic image of said set again. By being configured in this way, a computer in which this program is installed can realize each function based on this program.

  According to the present invention, an optimal tomographic image of a subject can be automatically acquired.

  Hereinafter, the best mode (hereinafter referred to as “embodiment”) for carrying out the tomographic plane image generation apparatus and the tomographic plane image generation method of the present invention is divided into a first embodiment and a second embodiment with reference to the drawings. Will be described in detail.

(First embodiment)
[Configuration of tomographic image generation system]
FIG. 1 is a configuration diagram of a tomographic image generation system including a tomographic plane image generation apparatus according to an embodiment of the present invention.
The tomographic image generation system 1 generates a dental tomographic image, and includes a panoramic tomography apparatus 2, a multi-tomographic image processing apparatus 3, and a tomographic plane image generation apparatus 4 as shown in FIG. Yes.

A known apparatus can be used as the panoramic tomography apparatus 2.
The multi-tomographic image processing device 3 and the tomographic image generation device 4 are general computers (computers), for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). ), An HDD (Hard Disk Drive), and an input / output interface.

  The multi-tomographic image processing device 3 extracts a plurality of pieces of X-ray image information of the subject K acquired by the panoramic tomography apparatus 2 and superimposes a plurality of predetermined tomographic planes formed by superimposing them. The tomographic plane image information is generated. The extracted X-ray image information is tomographic image information in the vertical direction on the tomographic plane.

The tomographic plane image generation device 4 resets the tomographic plane of the subject K using the tomographic plane image information generated by the multi-tomographic image processing device 3 and generates an image of the reset tomographic plane. . Information about the generated image is output to the display device D. The display device D includes, for example, a CRT (Cathode Ray Tube), a liquid crystal display (LCD), a PDP (Plasma Display Panel), an EL (Electronic Luminescence), and the like.
Hereinafter, each device will be described in detail.

[Panorama tomography equipment]
The panoramic tomography apparatus 2 captures a tomographic image (orthopan tomography) at a predetermined tomographic plane along the dentition of the maxilla / mandible of the subject (person) K. The panoramic tomography apparatus 2 includes an X-ray source 5, an imaging unit 6, an arm 7, and a controller 8.

The panoramic tomography apparatus 2 photographs the subject K by rotating and sliding the X-ray source 5 and the imaging means 6 around the rotation center C of the arm 7.
The X-ray source 5 has a slit (not shown), and irradiates the subject K with a fan beam (X-ray fan beam) generated by emitting X-rays through the slit. Note that the fan beam is a beam that expands in a fan shape in the vertical direction and is narrowed in a line shape in the horizontal direction when the irradiation part of the X-ray source 5 is used as a fan.

  The imaging means 6 receives X-rays irradiated from the X-ray source 5 and transmitted through the subject K, and images a portion of the subject K where X-rays are transmitted at a predetermined frame rate. The imaging means 6 is an X-ray image sensor, an X-ray detector, or a combination thereof. Here, the image sensor is a thin film light sensor such as a CCD (Charge Coupled Device) image sensor, a CMOS image sensor, a TFT (Thin Film Transistor) sensor, or a CdTe sensor. The X-ray detector is an X-ray image intensifier (I.I.), a flat panel detector (FPD), or the like. Note that the X-ray image captured by the imaging unit 6 may be displayed on the display device D.

  The arm 7 holds the X-ray source 5 and the imaging means 6 at a predetermined interval. This interval is set to, for example, 30 cm to 1 m so that the subject K is accommodated between the X-ray source 5 and the imaging unit 6. The irradiation part of the X-ray source 5 and the light receiving surface of the imaging means 6 are arranged to face each other. The arm 7 is configured to be rotatable and slidable around the rotation center C. Thereby, the imaging unit 6 can capture a tomographic image in an arbitrary direction around the subject K while maintaining a predetermined distance between the X-ray source 5 and the imaging unit 6.

  The controller 8 controls the X-ray source 5, the imaging unit 6, and the arm 7. Although not shown, the controller 8 executes an arm driving unit such as an actuator and a predetermined program stored in a ROM or the like. Control means comprising a CPU and the like. The controller 8 irradiates the X-ray source 5 with X-rays at a predetermined timing, and acquires X-ray image information of the subject K imaged by the imaging means 6 in synchronization with the X-ray irradiation timing. Then, the controller 8 rotates the arm 7 at a predetermined angular velocity and repeats imaging in the same manner, acquires X-ray image information of the subject K for a plurality of frames, and acquires the acquired X-ray image information for the plurality of frames as a multi-tomographic image. Output to the processing device 3.

[Multi-tomographic image processing equipment]
The multi-tomographic image processing device 3 includes large-capacity frame image storage means (not shown) that accumulates X-ray image information for a plurality of frames output from the controller 8 of the panoramic tomography apparatus 2. Further, in the present embodiment, the multi-tomographic image processing device 3 superimposes a plurality of X-ray image information extracted for each frame in the horizontal direction, thereby obtaining tomographic plane image information indicating a preset tomographic plane image. Can be generated. As a method for generating the tomographic plane image information, for example, a known technique, for example, the principle disclosed in Japanese Patent Laid-Open No. 10-2111200 can be used.

The multi-tomographic image processing device 3 generates tomographic plane image information for a plurality of tomographic planes. A method of generating tomographic image information for a plurality of tomographic planes is arbitrary. For example, in one imaging, only one preset tomographic plane is set, and the tomographic plane image information for a plurality of tomographic planes is generated by changing the setting of the tomographic plane each time imaging is performed. It is good as well.
In addition, for example, the multi-tomographic image processing device 3 uses the X-ray image information so that a desired tomographic plane is obtained when the X-ray image information for each frame stored in a frame image storage unit (not shown) is combined and superimposed. These combinations may be changed as appropriate, and a plurality of pieces of tomographic image information for each combination may be generated.

In this embodiment, as described above, the multi-tomographic image processing device 3 generates a plurality of pieces of tomographic image information by appropriately changing the combination of X-ray image information for each frame. Hereinafter, an outline of this method will be described using specific examples.
FIG. 2 is an explanatory diagram for explaining a method of generating tomographic plane image information by the multi-tomographic image processing apparatus shown in FIG. In FIG. 2, for the sake of simplicity, it is assumed that the subject K is a cylindrical object. FIG. 2 is a view of the subject K viewed from above.

Here, in the subject K shown in FIG. 2, the tomographic plane K ₁ whose distance from the center axis of the cylinder (the center of the circle in FIG. 2) is R ₁ and the tomography whose distance from the center axis of the cylinder is R _2. A plane K ₂ and a tomographic plane K ₃ whose distance from the central axis of the cylinder is R ₃ are assumed. On the extension of the central axis of the cylinder, a rotation center C of the arm 7 (see FIG. 1) is disposed (in FIG. 2, the center of the circle coincides with the rotation center). In actual panoramic photography, the arm 7 (see FIG. 1) performs a rotation operation and a slide operation, so the rotation center C moves during the panoramic photography.

Further, the intersections of the straight line Q ₁ connecting the X-ray source 5 and the imaging means 6 with the tomographic plane K ₁ , the tomographic plane K _2, and the tomographic plane K ₃ are point X ₁ , point X ₂ and point X ₃ , respectively. And Note that the point X ₁ , the point X _2, and the point X ₃ correspond to portions obtained by linearly slicing the tomographic plane on the tomographic plane K ₁ , the tomographic plane K _2, and the tomographic plane K ₃ , respectively. Here, for example, the imaging means 6 is a CMOS image sensor, and the size of one pixel of the CMOS image sensor is 100 μm. The distance R ₁ , the distance R _2, and the distance R ₃ are 300 mm, 150 mm, and 100 mm, respectively.

When the tomographic plane K ₁ (circumference 1884 mm) of the subject K is imaged stepwise or continuously while shifting one pixel at an imaging angle of 360 °, X-ray image information for each frame of 18840 frames is obtained. The identification information obtained by arranging these X-ray image information in time series is assumed to be i (i = 1 to 18840). All the X-ray image information is stored in a frame image storage means (not shown) of the multi-tomographic image processing apparatus 3.

Multi tomogram processing apparatus 3, using all the X-ray image information of the identification information i = 1 to 18,840, by overlapping and staggered by one pixel size of a CMOS image sensor (100 [mu] m), fault plane K ₁ (radius 300mm) tomographic image information is generated.

Further, the multi-tomographic image processing device 3 reads out the stored X-ray image information by removing one frame, and uses these X-ray image information (identification information i = 1, 3,..., 18837, 18839) to perform CMOS. The tomographic plane image information of the tomographic plane K ₂ (radius 150 mm) is generated by superimposing the image sensor by shifting by one pixel size.

Further, the multi-tomographic image processing device 3 reads out the stored X-ray image information without extracting two frames, and uses these X-ray image information (identification information i = 1, 4,..., 18836, 18839) to perform CMOS. The tomographic plane image information of the tomographic plane K ₃ (radius of 100 mm) is generated by superimposing the image sensor by shifting by one pixel size.

That is, the multi-tomographic image processing device 3 uses the predetermined reference, for example, the distance R ₁ (radius 300 mm) indicating the tomographic plane K ₁ (circumference 1884 mm) of the subject K to store the accumulated X-ray image information. By superimposing n frames, the tomographic image information of the tomographic surface having a radius of [300 / (1 + n)] mm is generated.

  Here, n is a natural number, for example, a tomographic plane (for example, a radius of 50.5 mm) between a tomographic plane when n = 5 (radius 50 mm) and a tomographic plane when n = 4 (radius 60 mm). When this information is necessary, the multi-tomographic image processing device 3 performs the following processing. In this case, X-ray image information with 5 frames removed is used in accordance with the smaller radius (the tomographic plane when n = 5 (radius 50 mm)). The X-ray image information for each frame to be used is 3140 (= 18840/6) frames.

Each X-ray image information accumulated in a frame image storage means (not shown) is given an address on the memory for each pixel (100 μm) of the CMOS image sensor. As shown in FIG. 2, if the X-ray irradiation range is an area sandwiched between the straight line Q ₁ and the straight line Q ₂ , the portion on the tomographic plane corresponding to the area is imaged by one pixel (100 μm). The Here, for example, 10 addresses on the memory are assigned. Numerical values indicating these addresses are j (j = 1 to 10).

The multi-tomographic image processing apparatus 3 performs a predetermined conversion on a numerical value j ₀ (j = 1 to 10) indicating an address of “i = 1 X-ray image information” read from the stored X-ray image information. Is set in another address space (second address) on the memory, and image information for each pixel size constituting “i = 1 X-ray image information” is associated with this second address.
j ₀ = 1,100,200,300,400,500,600,700,800,900

Next, the multi-tomographic image processing device 3 indicates the address of “i = 7 X-ray image information” to be read out from the stored X-ray image information by removing 5 frames from “i = 1 X-ray image information”. numeric j (j = 1~10) a numerical value j ₁ subjected to predetermined conversion is set to the second address, the image information of each pixel size constituting the "X-ray image information of the i = 7" Corresponding to this second address.
j ₁ = 101,201,301,401,501,601,701,801,901,1001

Further, the multi-tomographic image processing apparatus 3 sets a numerical value j (j = 1 to 10) indicating an address of “i = 13 X-ray image information” read out by removing 5 frames from “i = 7 X-ray image information”. A numerical value j ₂ subjected to a predetermined conversion is set as a second address, and image information for each pixel size constituting “i = 13 X-ray image information” is associated with the second address.
j ₂ = 202,302,402,502,602,702,802,902,1002,1102

These conversions for the numerical value indicating the address are for shifting the image information for each pixel size of each frame by shifting them by 101 μm.
Similarly, the image information is associated with the second address while converting the numerical value j (j = 1 to 10) indicating the addresses of the X-ray image information for 3140 frames. Finally, the multi-tomographic image processing apparatus 3 superimposes all (3140) image information for each pixel size constituting the X-ray image information read out by removing 5 frames on the second address, It is possible to generate tomographic image information (image information for 360 ° of the circumference having a radius of 50.5 mm) on a tomographic surface having a radius of 50.5 mm.

Further, when the image information for each pixel size of each frame is overlaid while being shifted by 102 μm, for example, tomographic image information of a tomographic surface having a radius of 51 mm can be generated. In this case, the numerical value j ₁ , the numerical value j _2, etc. are as follows.
j ₁ = 102,202,302,402,502,602,702,802,902,1002
j ₂ = 203,303,403,503,603,703,803,903,1003,1103

Similarly, when image information for each pixel size of each frame is overlaid while being shifted by 110 μm, for example, tomographic image information of a tomographic surface having a radius of 55 mm can be generated. In this case, the numerical value j ₁ , the numerical value j _2, etc. are as follows.
j ₁ = 105,205,305,405,505,605,705,805,905,1005
j ₂ = 206,306,406,506,606,706,806,906,1006,1106

FIG. 3 is an explanatory diagram showing a specific example of a plurality of tomographic planes targeted by the multi-tomographic image processing apparatus shown in FIG. In the state shown in FIG. 3, the front tooth portion B of the person who is the subject K (see FIG. 1) is directed to the imaging means 6, and the molar tooth portion N of the person is directed to the X-ray source 5. The X-ray source 5 and the imaging means 6 rotate and slide. Here, the reference tomographic plane among the tomographic planes F of the dentition is F ₀ . In addition, a tomographic plane closer to the cheek side than the tomographic plane F ₀ is defined as F ₁ . Further, the tomographic plane on the lingual side of the tomographic plane F ₀ is defined as F ₋₁ .

4 is an explanatory diagram showing tomographic plane image information generated by the multi-tomographic image processing apparatus shown in FIG. 1, wherein (a) is tomographic plane image information corresponding to the tomographic plane shown in FIG. ) Shows X-ray image information forming the tomographic image information.
The tomographic plane image information f ₁ shown in FIG. 4A is an example of tomographic plane image information on the tomographic plane F ₁ shown in FIG. The tomographic plane image information f ₀ shown in FIG. 4A is an example of the tomographic plane image information on the tomographic plane F ₀ shown in FIG. 3, and the tomographic plane image information f ₋₁ shown in FIG. _These are examples of tomographic plane image information on the tomographic plane F- ₁ shown in FIG.

As shown in FIG. 4 (a), the horizontal widths of the respective tomographic plane image information are different, and are longer from the rotation center C (see FIG. 3) toward the cheek side surface.
The X-ray image information g shown in FIG. 4B is superposed at a predetermined interval to form the tomographic plane image information f ₀ .
The multi-tomographic image processing device 3 uses a plurality of X-ray image information (for example, g) extracted for each frame and a plurality of generated tomographic plane image information (for example, f ₁ , f ₀ , f ₋₁ ) The image is output to the surface image generation device 4.

[Tomographic image generator]
FIG. 5 is a functional block diagram showing an example of the tomographic image generating apparatus according to the first embodiment of the present invention. As shown in FIG. 5, the tomographic plane image generation device 4 includes an input / output unit 11, a processing unit 12, and a storage unit 13.

<Input / output unit>
The input / output unit 11 includes, for example, a communication interface and the like, and inputs predetermined commands and information and outputs predetermined information. Specifically, the input / output unit 11 inputs X-ray image information and tomographic plane image information from the multi-tomographic image processing device 3.

<Processing unit>
The processing unit 12 includes, for example, a CPU (Central Processing Unit) and the like, controls the input / output unit 11 and the storage unit 13, and mainly based on tomographic plane image information acquired through the input / output unit 11. An image of the reset tomographic plane is generated. In the present embodiment, as shown in FIG. 5, the processing unit 12 includes a spectrum information generation unit 121, a high frequency region extraction unit 122, a model generation unit 123, a tomographic plane resetting unit 124, and an image information synthesis unit 125. It was decided to prepare.

  The spectrum information generation unit 121 obtains a plurality of tomographic plane image information (see FIG. 4) corresponding to a plurality of tomographic planes (see FIG. 3) for the subject K (see FIG. 1) from the tomographic plane image storage unit 132 described later. A plurality of pieces of spectrum information, which is information obtained by frequency conversion of the read tomographic plane image information, is generated. Here, the frequency conversion method is not particularly limited. For example, FFT (Fast Fourier Transform), wavelet transformation (Wavelet Transformation), high-pass filter convolution (Convolution) or the like may be used. The spectrum information generated by such frequency conversion is output to the high frequency region extraction means 122. For example, in the case of FFT, each tomographic plane image information may be divided into a vertical area sliced in the vertical direction and a horizontal area sliced in the horizontal direction, and frequency conversion may be performed for each divided area. . Also, among each tomographic image information, for example, specific information such as the horizontal area of the lower base (or upper base) corresponding to the root apex of the dentition, or the central vertical area corresponding to the cheek side surface side, etc. The divided area may be determined from the information. Furthermore, each tomographic plane image information may be divided into fine blocks, and frequency conversion may be performed for each of the divided blocks.

  The high frequency region extraction unit 122 extracts, based on the input spectrum information, position information of a high frequency region that is a region having the highest high frequency component value among a plurality of tomographic plane image information for each predetermined position of the subject K. To do. The high-frequency region corresponds to a region that is in focus more than the images of other tomographic planes at a predetermined position of the subject K (see FIG. 1) when the tomographic plane image information of a certain tomographic plane is displayed as an image. . Information about the extracted high frequency region is output to the model generation unit 123.

  The model generation means 123 corresponds to the position information of a plurality of predetermined tomographic planes (see FIG. 3) of the subject K (see FIG. 1) and the position information of the high frequency area extracted by the high frequency area extraction means 122, respectively. A multi-fault model that is an attached model is generated. The generated multi-fault model is output to the fault plane resetting means 124.

  The tomographic plane resetting means 124 resets the tomographic plane by connecting the high-frequency areas extracted for each predetermined position of the subject (K) (see FIG. 1) in the input multi-fault model, and also resets the high-frequency areas. For each position information, the overlap width of the X-ray image information is obtained from the distance between the position of the high frequency region and the rotation center C (see FIG. 1). Here, resetting means setting a new fault plane different from the fault plane set in the input multi-fault model. Further, the tomographic plane resetting means 124 interpolates between the high-frequency regions extracted for each predetermined position. The interpolation method is not particularly limited. For example, it is possible to perform interpolation so as to draw a smooth curve using interpolation by spline conversion processing. Further, a sum obtained by calculating a predetermined weight on the position information of the high-frequency region (sample point) associated with each tomographic plane may be calculated and interpolated. In this case, average value interpolation is preferred. Information regarding the reset tomographic plane is output to the image information combining unit 125.

  The image information synthesizing unit 125 synthesizes the X-ray image information corresponding to the predetermined position of the subject (K) (see FIG. 1) with the overlap width of the X-ray image information obtained for the reset tomographic plane. Thus, an image of the reset tomographic plane is generated. Further, the image information synthesizing unit 125 reads out the X-ray image information to be superimposed from the frame image storage unit 131 described later, and synthesizes the read out X-ray image information, thereby generating a reset tomographic plane image. . The image information synthesizing unit 125 stores information on the generated image in the reset tomographic plane image storage unit 133 described later.

<Storage unit>
The storage unit 13 includes, for example, a RAM and an HDD. In this case, the RAM is used for arithmetic processing by the processing unit 12 and stores information acquired through the input / output unit 11. The HDD stores various databases, predetermined programs, and processing of the processing unit 12. Stores results etc.

As shown in FIG. 5, the storage unit 13 includes a frame image storage unit 131, a tomographic plane image storage unit 132, and a reset tomographic plane image storage unit 133.
The frame image storage unit 131 stores X-ray image information (for example, g) illustrated in FIG. 4B, and is configured by a general HDD. The processing unit 12 stores the X-ray image information acquired from the multi-tomographic image processing device 3 via the input / output unit 11 in the frame image storage unit 131.

The tomographic plane image storage means 132 stores the tomographic plane image information (for example, f ₁ , f ₀ , f ₋₁ ) illustrated in FIG. 4A, and is composed of a general HDD. The processing unit 12 stores the tomographic plane image information acquired from the multi-tomographic image processing device 3 via the input / output unit 11 in the tomographic plane image storage unit 132.
The reset tomographic plane image storage unit 133 stores the tomographic plane image information reset by the tomographic plane resetting unit 124, and includes a general HDD.

  Note that the spectrum information generating unit 121, the high frequency region extracting unit 122, the model generating unit 123, the tomographic plane resetting unit 124, and the image information synthesizing unit 125 included in the processing unit 12 are stored in the storage unit 13 by the CPU. This is realized by expanding and executing a predetermined program stored in the ROM or the like in the RAM. Therefore, the tomographic plane image generation apparatus 4 can also be realized by executing a tomographic plane image generation program that causes a general computer to execute the above-described units 121 to 125. These programs can be distributed via a communication line, or can be written on a recording medium such as a CD-ROM for distribution.

[Specific examples of information handled by the processing unit]
Next, a specific example of information handled by the processing unit 12 will be described with reference to FIGS. 6 to 9 (see FIG. 5 as appropriate). 6 to 9 are explanatory diagrams of specific examples of information handled by the processing unit shown in FIG. 5. FIG. 6 is an explanatory diagram of a method for extracting a high frequency region based on spectrum information. Shows the case where FFT is used, and (b) shows the case where wavelet transform is used. 7A shows spectral information and a high frequency region, FIG. 7B shows a multi-fault model, FIG. 8 shows reset tomographic planes, and FIG. 9 shows image information of reset tomographic planes. Yes.

  For example, the spectrum information generation unit 121 generates spectrum information h by FFT from predetermined tomographic screen information f as shown in FIG. At that time, the tomographic screen information f is divided into, for example, five vertical areas fa, fb, fc, fd, and fe, and each is subjected to frequency conversion, whereby the spectrum information ha, hb, hc, hd, and he are obtained. Can be generated. That is, plural (five) pieces of spectrum information are generated for one tomographic plane. When each spectrum information ha, hb, hc, hd, and he is displayed as a vertically long rectangle as shown in FIG. 6A, the vertical indicates the vertical frequency component and the horizontal indicates the horizontal frequency component. In this rectangle, as an example, the higher the frequency is on the upper side and on the right side. Therefore, in this case, the high frequency region extracting means 122 compares the comparison region 601 at the upper right corner of the rectangle with the comparison regions in the other tomographic plane image information for each spectrum information ha, hb, hc, hd, and he. Then, spectral information corresponding to the high frequency region is extracted.

  Further, for example, as shown in FIG. 6B, the spectrum information generating unit 121 generates spectrum information h from predetermined tomographic screen information f by wavelet transform. That is, one piece of spectral information is generated for one tomographic plane. In this case, as shown in FIG. 6B, the spectrum information h is displayed in a rectangle, the upper left block of the rectangle has a DC component block 602 indicating a DC component, and the lower right block has the highest frequency. The high frequency block 603 is divided into blocks. And the high frequency area | region extraction means 122 can extract the positional information on the high frequency area | region in the tomographic plane image information f from the highest frequency block 603 of the acquired spectrum information h. Here, the vertical and horizontal lengths of the highest frequency block 605 reflect the positional information (Y coordinate, X coordinate) of the basic tomographic plane image information f. Thus, even when spectral information is extracted by wavelet transform, it may be performed after the tomographic plane image information f is divided into a plurality of areas, as in FFT. In that case, the amount of calculation can be reduced.

In FIG. 6, the relationship between one tomographic plane (tomographic screen information) and its spectrum information has been described. Next, in FIG. 7, a relationship between a plurality of tomographic planes (tomographic screen information) and spectrum information thereof will be described.
For example, when the five pieces of tomographic plane image information f ₂ , f ₁ , f ₀ , f ₋₁ , and f ₋₂ are read from the tomographic plane image storage unit 132, the spectrum information generating unit 121 responds to them. Then, as shown in FIG. 7A, for example, five pieces of spectrum information h ₂ , h ₁ , h ₀ , h ₋₁ , and h ₋₂ are generated. Note that the five tomographic plane image information f ₂ , f ₁ , f ₀ , f ₋₁ , and f ₋₂ are the five tomographic planes F ₂ , F ₁ , F ₀ , F ₋ as illustrated in FIG. ₁ and F _-2 (FIG. 3 illustrates three tomographic planes). Here, the tomographic plane F ₂ is arranged closer to the cheek side than the tomographic plane F ₁ , and the tomographic plane F _-2 is arranged closer to the lingual side than the tomographic plane F ₋₁ .

For example, the high-frequency region extracting unit 122 performs spectrum analysis on the five pieces of spectral information h ₂ , h ₁ , h ₀ , h ₋₁ , and h _−2, thereby corresponding to a predetermined position of the subject, as shown in FIG. as shown in), for example, to extract a high-frequency region 701 (two locations) to the spectral information h _2. Similarly, the high frequency region extracting unit 122 extracts a high frequency region 701 as shown in FIG. 7A with respect to the spectrum information h ₁ , h ₀ , h ₋₁ , and h ₋₂ . Note that the number of high-frequency regions extracted for one piece of spectrum information is arbitrary.

For example, when the spectrum information generation unit 121 generates five pieces of spectrum information h ₂ , h ₁ , h ₀ , h ₋₁ , and h ₋₂ , the model generation unit 123 corresponds to the subject, As shown in FIG. 7B, for example, information on five tomographic planes (subject tomographic plane information) m ₂ , m ₁ , m ₀ , m ₋₁ , m ₋₂ is generated. Note that the subject tomographic plane information m ₂ , m ₁ , m ₀ , m ₋₁ , m ₋₂ is five tomographic planes F ₂ , F ₁ , F ₀ , F ₋₁ , F as illustrated in FIG. _This is two-dimensional position information in the horizontal direction corresponding to _-2 (in FIG. 3, three tomographic planes are illustrated).

The model generation means 123 is a high frequency region extraction means 122. For example, a high frequency region 701 (FIG. 7A) is obtained from five pieces of spectrum information h ₂ , h ₁ , h ₀ , h ₋₁ , and h ₋₂ . When extracted, as shown in FIG. 7B, the high-frequency region 701 (FIG. 7A) is _{added to} each of the tomographic plane information m ₂ , m ₁ , m ₀ , m ₋₁ , and m ₋₂ . Nine sample points 702 corresponding to the position information are associated with each other to generate a multi-fault model M ₁ .

For example, when the tomographic plane resetting unit 124 acquires a multi-fault model in which nine sample points are associated with each other, the sample points 8a to 8i are connected to each other as shown in FIG. by interpolating the positional information of 8A～8i, to produce a multi-fault model M ₂ interpolated with them it was smoothly connected curve. The position information of the connected curve indicates the reset tomographic plane G.
The tomographic plane resetting means 124 obtains the distance (rotation radius) between the positions of the sample points 8a to 8i and the rotation center position C ′. In FIG. 8, as a turning radius, the distance from the rotational center sample points 8a, to 8e r _a, exemplifying a r _e. The overlap width of the X-ray image information is proportional to the angular velocity and the rotation radius of the arm 7 (see FIG. 1) when the same number of X-ray image information is used regardless of the rotation radius. It is inversely proportional to the frame rate of the hour. Using this principle, the tomographic plane resetting means 124 considers the rotation and slide around the rotation center of the arm 7 (see FIG. 1), and sets the overlap width of the X-ray image information at a predetermined position of the subject. Ask. In FIG. 8, only one rotation center position C ′ is displayed for easy understanding of how to obtain the overlapping width. In actual panoramic shooting, the arm 7 (see FIG. 1) performs a rotating operation and a sliding operation, so that the rotation center C moves during the panoramic shooting. Therefore, when obtaining the distance (rotational radius) between the position of each sample point 8a to 8i and the rotation center position C ', the rotation at the respective position when the X-ray image of the position of each sample point 8a to 8i is taken. The center C is obtained as a reference.

The image information synthesizing unit 125 reads out the X-ray image information corresponding to the predetermined position of the subject K (see FIG. 1) from the frame image storage unit 132, and sets the overlap width of the X-ray image information obtained with respect to the tomographic plane G. Based on this, the read X-ray image information is synthesized. Thereby, as shown in FIG. 9, the tomographic plane image information f ′ of the reset tomographic plane G is generated. The generated image information f ′ is newly generated tomographic plane image information, unlike tomographic plane image information corresponding to a predetermined tomographic plane (see FIG. 4: for example, f ₀ ).
In FIG. 9, a section indicated by an arrow 8a corresponds to the position of the sample point 8a shown in FIG. 8, and the X-ray image information has the same overlapping width in this section. The same applies to the arrows 8b and thereafter. Also, as shown in FIG. 9, for example, the overlapping width in the section indicated by the arrow 8a is different from the overlapping width in the section indicated by the arrow 8b. Further, for example, the overlapping width in the section between the section shown by the arrow 8a and the section shown by the arrow 8b is gradually changed. The change at this time may be continuous or stepwise. Note that, for example, the overlap width in a section indicated by an arrow may be the same as the overlap width in a section indicated by another arrow.

  The tomographic plane image generation apparatus 4 according to the present embodiment detects the most focused position in the tomographic plane image for each predetermined position of the subject K from a plurality of tomographic plane image information, and detects the most focused ones detected. The optimum tomographic plane is automatically reset by superimposing the X-ray image information with the overlapping width corresponding to the matching position. Therefore, the sample points 8a to 8i illustrated in FIG. 8 are examples. For example, in the example shown in FIG. 8, since the sample points 8a to 8i are obtained with respect to plural (five) subject tomographic plane information, the reset tomographic plane G is determined in advance. It is across multiple fault planes. However, when all the sample points 8a to 8i are obtained for only one subject tomographic plane information, the reset tomographic plane G does not always cross a plurality of predetermined tomographic planes. Absent. Also, depending on the individual, the reset tomographic plane G may match a predetermined tomographic plane indicated by one subject tomographic plane information.

[Operation of tomographic image generator]
The overall operation of the processing unit of the tomographic plane image generation device 4 shown in FIG. 5 will be described with reference to FIG. 10 (see FIGS. 1 and 5 as appropriate). FIG. 10 is a flowchart showing the overall operation of the processing unit of the tomographic plane image generation device shown in FIG. The tomographic plane image generation device 4 uses the frame image storage means 131 and the tomographic plane image storage means respectively to obtain the X-ray image information and tomographic plane image information acquired from the multi-tomographic image processing apparatus 3 via the input / output unit 11 in advance. It is stored in 132.

First, the tomographic plane image generation device 4 is information obtained by frequency-converting a plurality of tomographic plane image information (see FIG. 4) corresponding to a plurality of tomographic planes (see FIG. 3) of the subject K by the spectrum information generation unit 121. A plurality of pieces of spectrum information (see FIG. 7A: for example, h _{2 to} h ₋₂ ) are generated (step S1: spectrum information generation step). Then, the tomographic plane image generation device 4 extracts the high frequency area 701 (see FIG. 7A) from the tomographic plane image information for each predetermined position of the subject K based on the spectrum information by the high frequency area extraction unit 122. (Step S2: High-frequency region extraction step).

Subsequently, the tomographic plane image generating apparatus 4 uses the model generating unit 123 to perform subject tomographic plane information (see FIG. 7B: for example, m ₀ ) and position information of the high-frequency region 701 (see FIG. 7A). preparative is respectively associated model multi fault model M ₁ to produce a (see FIG. 7 (b)) (step S3: model generation step). Then, the tomographic plane image generation apparatus 4 interpolates between the position information of the sample points 8a to 8i (see FIG. 8) of the multi-fault model M ₁ (see FIG. 7B) by the tomographic plane resetting means 124. As a result, the tomographic plane is reset and the reset tomographic plane G (see FIG. 8) is generated, and the overlapping width of the X-ray image information is obtained (step S4: tomographic plane resetting step).

  Finally, the tomographic plane image generation device 4 reads out X-ray image information corresponding to a predetermined position of the subject K (see FIG. 1) from the frame image storage unit 132 by the image information synthesis unit 125 and obtains the tomographic plane G. Based on the overlap width of the obtained X-ray image information, for example, as shown in FIG. 9, the read X-ray image information is synthesized (step S5: image information synthesis step). The combined image information is stored in the reset tomographic plane image storage means 133 and is displayed on the display device D as appropriate.

  According to the first embodiment, for each predetermined position of the subject K, the optimum tomographic plane is automatically re-established by extracting the most in-focus portions from the plurality of tomographic plane image information. Can be set. Therefore, it is possible to acquire a sharp tomographic image that is in focus even for an individual who has a dentition that does not conform to a predetermined normal position in the apparatus. Conventionally, a dentist has to select a suitable type for a patient from a plurality of types predetermined for each size and shape of the dentition. The operator selecting the mold does not need to be proficient in selecting a mold. In addition, a clear tomographic image in focus can be acquired even if the dentition of the subject is not correctly aligned with the normal position set by the apparatus.

(Second Embodiment)
[Configuration of tomographic image generator]
The tomographic plane image generation apparatus of the second embodiment has the same configuration as the tomographic plane image generation apparatus 4 shown in FIG. 5 except that the configuration of the image information synthesis means 125 is different in the processing unit 12. While omitting the drawing, the description of the same configuration is omitted.

<Image information synthesis means>
FIG. 11 is a functional block diagram showing another configuration example of the image information synthesizing means shown in FIG.
As shown in FIG. 11, the image information composition unit 125 </ b> A includes a vertical direction correction unit 201 and a horizontal direction correction unit 202.

<Specific Example of Operation of Image Information Combining Unit>
Here, a specific example of the operation of the image information synthesizing unit 125A will be described with reference to FIG. FIG. 12 is an explanatory diagram showing a state in which the dentition is aligned at a position shifted from the normal position at the time of photographing. Here, it is assumed that the tomographic plane image generation device 4 is configured on the assumption that the dentition of the person who is the subject K is arranged at the position (normal tomographic position) indicated by the broken line of T ₁ . In other words, the tomographic plane image generation device 4 determines the shooting aim so that the normal tomographic position is in focus. On the other hand, teeth of a person as a subject K is the result of the calibration (calibration), it is assumed that it is detected that is disposed at a position indicated by the solid line in T _2. Here, T ₂ is the same as the reset tomographic plane G shown in FIG. The position of the dentition indicates the position of the tomographic plane and corresponds to a predetermined position for aligning the position of the tomographic plane desired to be imaged. This predetermined position may be, for example, the position of a chin rest on which a person to be photographed places a chin. Then, the position of the dentition is calculated backward from this predetermined position.

As shown in FIG. 12, when the position of the broken line of T ₁ is close to the X-ray source 5, if the image information synthesizing unit 125A does not operate, the size of the image showing the dentition of the subject K is The size of the image assumed by the surface image generation device 4 is enlarged. On the other hand, when the position of the broken line of T ₁ is far from the X-ray source 5, the size of the image showing the dentition of the subject K is the tomographic plane image generation device 4 without the operation of the image information synthesis unit 125 A. The image size is reduced from that assumed in the above.

  Further, when resetting the tomographic plane, if the sample points 8a to 8i (see FIG. 8) are brought close to the rotation center C, the size of the image indicating the dentition of the subject K will be described if the image information synthesizing unit 125A is not operated. However, the size of the image assumed by the tomographic plane image generation device 4 is reduced. On the other hand, if it is far away, it will expand. Therefore, when there is no operation of the image information synthesizing means 125A, the image must be manually enlarged or reduced.

  Therefore, the tomographic plane image generation device 4 of the second embodiment is configured to automatically correct the enlargement / reduction of the image by the image information synthesis unit 125A. This correction method will be described with reference to FIG. FIG. 13 is an explanatory diagram for explaining a method of correcting the photographed image of the dentition shown in FIG.

  As shown in FIG. 13, a is the distance between the X-ray source 5 and the normal tomographic position (predetermined tomographic plane position) on the straight line connecting the X-ray source 5 and the imaging means 6. Further, L is a difference (deviation from a predetermined tomographic plane) between the position of the dentition and the normal tomographic position on this straight line. Further, r is the distance between the rotation center C and the normal fault position (predetermined fault plane position) on this straight line.

FIG. 11 will be referred to again.
The vertical direction correcting unit 201 performs correction for enlarging an image of the reset tomographic plane (see FIG. 8: for example, G) in the vertical direction at an enlargement ratio P shown in Expression (1).

P = (a−L) / a (1)
However, a and L show a and L shown in FIG.

  The horizontal direction correction unit 202 performs correction to enlarge the image of the reset tomographic plane (see FIG. 8: for example, G) in the horizontal direction at the enlargement ratio H shown in Expression (2).

H = r × (a−L) / {a × (r−L)} (2)
However, a and L are respectively the same as what was shown to Formula (1), and r shows r shown in FIG.

  According to the second embodiment, even when the dentition of the subject is not aligned with a predetermined normal position at the time of shooting, the size of the image showing the dentition of the subject K is automatically enlarged / reduced. Reduction correction is performed. Further, even when an image formed on the reset tomographic plane is enlarged / reduced, it can be automatically corrected.

  As mentioned above, although each embodiment of this invention was described, this invention is not limited to these, It can implement in the range which does not change the meaning. For example, the subject tomographic plane information generated by the model generating unit 123 has been described as being two-dimensional position information in the horizontal direction that does not include a vertical component. There may be. In this case, the high frequency region extraction unit 122 extracts three-dimensional position information regarding the position information of the tomographic plane image information when extracting the high frequency region. The information regarding the vertical component may be, for example, information indicating the number of tomographic layers from one end among predetermined tomographic surfaces.

  In each embodiment, the tomographic plane image generation device 4 has been described as one element of the tomographic image generation system 1, but may be configured to include the multi-tomographic image processing device 3. Furthermore, the configuration of the panoramic tomography apparatus 2 may be included. In addition, the tomographic image generation device 4 is not necessarily configured by a single housing (unit), and the storage unit 13 may be provided in an external storage device that is an external unit.

  Moreover, although each embodiment demonstrated as a dental apparatus, this invention is not limited to this, It can comprise also as a medical apparatus applied to parts other than the dentition of a human body. Furthermore, the subject is not limited to a person (human body), and may be an object such as a mineral. When such an object is a subject, it can be applied to nondestructive inspection by acquiring an image of the tomographic plane of the object.

1 is a configuration diagram of a tomographic image generation system including a tomographic plane image generation apparatus according to an embodiment of the present invention. It is explanatory drawing which shows the principle of the multitomographic image processing by the multitomographic image processing apparatus shown in FIG. It is explanatory drawing which shows three tomographic surfaces of a dentition. FIG. 4 is an explanatory diagram illustrating multi-tomographic image processing of the multi-tomographic image processing apparatus illustrated in FIG. 1, where (a) represents tomographic plane image information corresponding to the tomographic plane illustrated in FIG. 3, and (b) represents tomographic plane image information. X-ray image information forming each is shown. It is a functional block diagram showing an example of a tomographic image generating device concerning a 1st embodiment of the present invention. It is a clarification figure of the extraction method of the high frequency field based on spectrum information, (a) shows the case where FFT is used, and (b) shows the case where wavelet transform is used, respectively. FIG. 6 is an explanatory diagram of processing by the processing unit shown in FIG. 5, where (a) shows spectral information and a high-frequency region, and (b) shows a multi-fault model. It is explanatory drawing of the tomographic plane reset by the process part shown in FIG. FIG. 6 is an explanatory diagram of tomographic plane image information of a tomographic plane reset by the processing unit illustrated in FIG. 5. It is a flowchart which shows the tomographic plane image generation process by the tomographic plane image generation apparatus shown in FIG. It is a functional block diagram which shows another structural example of the image information synthetic | combination means shown in FIG. It is explanatory drawing which shows the dentition aligned at the time of imaging | photography. It is explanatory drawing for demonstrating the method of correct | amending the picked-up image of the dentition shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tomographic image generation system 2 Panoramic tomography apparatus 3 Multi-tomographic image processing apparatus 4 Tomographic plane image generation apparatus 5 X-ray source 6 Imaging means 7 Arm C Rotation center D Display apparatus 11 Input / output part 12 Processing part 121 Spectral information generation means 122 High-frequency region extraction means 123 Model generation means 124 Tomographic plane resetting means 125 (125A) Image information synthesis means 13 Storage unit 131 Frame image storage means 132 Tomographic plane image storage means 133 Reset tomographic plane image storage means 201 Vertical direction correction means 202 Horizontal correction means

Claims (5)

Photographed by a panoramic tomography apparatus for photographing the subject by rotating and sliding an X-ray source for irradiating the subject with X-rays and an imaging means for receiving X-rays transmitted through the subject around a predetermined rotation center Re-setting the tomographic plane of the subject using a plurality of tomographic plane image information corresponding to a plurality of predetermined tomographic planes formed by superimposing a plurality of X-ray image information of the subject, A tomographic image generation device that generates an image of a reset tomographic plane,
Spectrum information generating means for generating a plurality of spectrum information that is information obtained by frequency-converting a plurality of tomographic plane image information corresponding to a plurality of predetermined tomographic planes for the subject;
A high-frequency region that extracts position information of a high-frequency region that is a region having the highest value of a high-frequency component among the plurality of tomographic plane image information for each predetermined position of the subject based on the generated plurality of spectrum information Extraction means;
A model that generates a multi-fault model that is a model in which position information of the plurality of predetermined tomographic planes for the subject is associated with position information of the high-frequency region extracted for each predetermined position of the subject Generating means;
In the multi-fault model, the tomographic plane is reset by connecting the high-frequency regions extracted for each predetermined position of the subject, and the position of the high-frequency region and the rotation center are set for each position information of the high-frequency region. A tomographic plane resetting means for respectively obtaining the overlapping width of the X-ray image information from the distance of
By combining the X-ray image information corresponding to the predetermined position of the subject with the overlapping width of the X-ray image information obtained for the reset tomographic plane, the image of the reset tomographic plane is obtained. An image information synthesizing unit for generating a tomographic plane image generating apparatus. The X-ray source emits an X-ray fan beam spread in a vertical direction,
The image information synthesis means includes
Vertical direction correction means for performing correction to enlarge the reset tomographic image in the vertical direction at an enlargement ratio P shown in Equation (1);
2. The tomographic plane image according to claim 1, further comprising: a horizontal direction correcting unit that performs correction for enlarging the reset image of the tomographic plane in the horizontal direction at an enlargement ratio H shown in Expression (2). Generator.
P = (a−L) / a (1)
H = r × (a−L) / {a × (r−L)} (2)
Here, a represents the distance between the X-ray source and the predetermined position of the tomographic plane on a straight line connecting the X-ray source and the imaging means, and L represents the predetermined of the subject on the straight line. A deviation from the position of the obtained tomographic plane is indicated, and r indicates a distance between the rotation center and the predetermined position of the tomographic plane on the straight line. Photographed by a panoramic tomography apparatus for photographing the subject by rotating and sliding an X-ray source for irradiating the subject with X-rays and an imaging means for receiving X-rays transmitted through the subject around a predetermined rotation center Re-setting the tomographic plane of the subject using a plurality of tomographic plane image information corresponding to a plurality of predetermined tomographic planes formed by superimposing a plurality of X-ray image information of the subject, A tomographic plane image generation method of a tomographic plane image generation apparatus for generating a reset tomographic plane image,
The tomographic plane image generating device is
Spectral information generation step of generating a plurality of spectrum information that is information obtained by frequency-converting a plurality of tomographic plane image information corresponding to a plurality of predetermined tomographic planes for the subject,
A high-frequency region that extracts position information of a high-frequency region that is a region having the highest value of a high-frequency component among the plurality of tomographic plane image information for each predetermined position of the subject based on the generated plurality of spectrum information An extraction step;
A model that generates a multi-fault model that is a model in which position information of the plurality of predetermined tomographic planes for the subject is associated with position information of the high-frequency region extracted for each predetermined position of the subject Generation step;
In the multi-fault model, the tomographic plane is reset by connecting the high-frequency regions extracted for each predetermined position of the subject, and the position of the high-frequency region and the rotation center are set for each position information of the high-frequency region. A tomographic plane resetting step for obtaining the overlap width of the X-ray image information from the distance of
By combining the X-ray image information corresponding to the predetermined position of the subject with the overlapping width of the X-ray image information obtained for the reset tomographic plane, the image of the reset tomographic plane is obtained. A tomographic plane image generation method, comprising: an image information synthesis step for generating the image information. The X-ray source emits an X-ray fan beam spread in a vertical direction,
The image information synthesis step includes:
A vertical direction correction step of performing correction for enlarging the reset image of the tomographic plane in the vertical direction at an enlargement ratio P shown in Expression (1);
The tomographic plane image according to claim 3, further comprising: a horizontal direction correcting step of performing correction for enlarging the reset image of the tomographic plane in the horizontal direction at an enlargement ratio H shown in Expression (2). Generation method.
P = (a−L) / a (1)
H = r × (a−L) / {a × (r−L)} (2)
Here, a represents the distance between the X-ray source and the predetermined position of the tomographic plane on a straight line connecting the X-ray source and the imaging means, and L represents the predetermined of the subject on the straight line. A deviation from the position of the obtained tomographic plane is indicated, and r indicates a distance between the rotation center and the predetermined position of the tomographic plane on the straight line. Photographed by a panoramic tomography apparatus for photographing the subject by rotating and sliding an X-ray source for irradiating the subject with X-rays and an imaging means for receiving X-rays transmitted through the subject around a predetermined rotation center Re-setting the tomographic plane of the subject using a plurality of tomographic plane image information corresponding to a plurality of predetermined tomographic planes formed by superimposing a plurality of X-ray image information of the subject, To generate a reconstructed tomographic image, the computer
Spectral information generating means for generating a plurality of spectral information that is information obtained by frequency-converting a plurality of tomographic plane image information corresponding to a plurality of predetermined tomographic planes for the subject,
A high-frequency region that extracts position information of a high-frequency region that is a region having the highest value of a high-frequency component among the plurality of tomographic plane image information for each predetermined position of the subject based on the generated plurality of spectrum information Extraction means,
A model that generates a multi-fault model that is a model in which position information of the plurality of predetermined tomographic planes for the subject is associated with position information of the high-frequency region extracted for each predetermined position of the subject Generating means,
In the multi-fault model, the tomographic plane is reset by connecting the high-frequency regions extracted for each predetermined position of the subject, and the position of the high-frequency region and the rotation center are set for each position information of the high-frequency region. A tomographic plane resetting means for respectively obtaining the overlapping width of the X-ray image information from the distance of
By combining the X-ray image information corresponding to the predetermined position of the subject with the overlapping width of the X-ray image information obtained for the reset tomographic plane, the image of the reset tomographic plane is obtained. A tomographic plane image generation program that functions as an image information synthesis means for generating a tomographic image.

Images