JPH04144549A - Digital panorama x-ray photographing device - Google Patents

Abstract

PURPOSE:To obtain the panoramic image corresponding to an image on the inclined tomographic surface of a shape for intersecting obliquely plural cylindrical face-like tomographic surfaces by selecting images in prescribed positions as partial images from each panoramic image obtained with plural cylindrical face-like tomographic surfaces overlapped at a minute interval, and synthesizing these partial images. CONSTITUTION:An image of transmission X rays of a dention bow being a body to be photographed is photographed, a series of frame images are reproduced, and a fetch interval and a shift amount corresponding to a reference tomographic surface C are selected. Subsequently, in cylindrical face-like tomographic surfaces D1-D4, the fetch interval and the shift amount corresponding to the tomographic surfaces D1 and D4 of the inside and the outside intersecting with an inclined tomographic surface layer C1 are selected. Next, an operation is executed, based on the selected fetch interval and shift amount, and partial images D1-D4, of each panoramic image in a position in which the tomographic surfaces D1-D4 intersect with the tomographic surface C1, and a partial image C' obtained by eliminating each partial image thereof from the panoramic image of the tomographic surface C are derived. Subsequently, by fitting each partial image D1'-D4' into the partial image C', they are synthesized, and a panoramic image in which they become one body is obtained.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to an apparatus for obtaining two-dimensional panoramic images using arbitrary curved tomographic axes and clay images. In addition to panoramic X-ray imaging equipment for dental diagnosis that takes pictures of arches, tomography equipment for other parts of the human body, and tomography equipment for non-destructive testing of various objects (7
It can also be used.

<Prior art> This type of device 27- is a well-known dental panoramic X-ray imaging device that uses film. The source and the film are moved relative to each other at a given rate.

Dental arch separation 1. lh An X-ray image of the dental arch is formed as a panoramic image on the film 1 using X-rays.

In addition, this type of device has various problems caused by the photographic technology used in the ilm.6) The applicant has attempted to solve this problem by producing an image of the transparent X-cotton using electricity without using a film for finishing purposes. We have previously proposed an apparatus that processes images to obtain a desired panoramic image (for example, see Japanese Patent Publication No. 2-29329).

<Problems to be Solved by the Invention> The tomographic plane A1 on which a panoramic image is obtained in the conventional imaging method is a curved plane 61 by drawing together the left and right edges of the plane mj erected vertically lα. Eel cylindrical shape Tb)6
゜, - This is an inevitable result of the principle of the second pushing device, and there is no particular problem with normal dental arches (137). In the case of an affected tooth with biaxial inclination (,2, so-called protrusion)...
The two tomographic planes CJ cannot include everything from the root apex to the crown, and only a panoramic image can be obtained with the anterior tooth partially blurred. For this reason, when diagnosing the anterior teeth, it becomes necessary to move the tomographic plane slightly forward and backward and re-take the image (- and #), which increases the number of steps required for imaging and increases the amount of Xta that the patient has exposed to. There were problems such as stiffness.

The invention of ,-) solves the problems in the prior art, only needs to be imaged once, and then two panoramic images can be created for any tomographic plane. The objective is to develop a digital panoramic X 'Ep't = imaging device that can obtain a panoramic image of a tomographic plane that diagonally crosses a normal cylindrical tomographic plane, such as a tomographic plane that includes both axes. This is what was done.

<Means for Solving the Problems> In order to achieve the above-mentioned object, the apparatus of the present invention has an X-ray source placed opposite to each other with an object in between, and an X-ray source transmitted through the object.
a rotating means for integrally rotating an X-ray image detection unit for detecting a ray image around the subject; and the image storage means at predetermined time intervals, view 17 the continuous image information in the direction in which the image moves, and add each piece of image information while shifting it by a predetermined distance, Image processing means is provided for forming a panoramic image of an image on an arbitrary cylindrical tomographic plane by digital processing in accordance with the extraction interval and shift amount of each image information. Then, the image processing means selects each partial image at a predetermined position from the panoramic images obtained for a plurality of cylindrical tomographic planes that overlap at minute intervals, and synthesizes these partial sub-images. A fault plane (J
The apparatus is configured to obtain a panoramic image corresponding to an image of an inclined tomographic plane.

Examples of the above-mentioned inclined tomographic plane include those having a spherical shape or a shape similar to a slit.

Also, among the plurality of cylindrical tomographic planes, the most inner and the outermost tomographic planes that intersect with the inclined tomographic plane are detected based on the speed at which the target image moves in the continuous image information. , = determines the position of the partial image to be selected from each panoramic image.

Effect〉 One shot? '1' The frame image stored in the image storage means, for example, contains all the information about the object present in the path of the X-ray. According to the apparatus, the tomographic plane on which a panoramic image is formed is determined by the interval at which image information is retrieved from the image storage means and the amount of shift by which the position is shifted when adding each piece of image information. Since the interval and the shift amount can be set after imaging, the target tomographic plane can be arbitrarily selected using the included information. Therefore, panoramic images are obtained for each of multiple cylindrical tomographic planes that overlap at minute intervals, images located on inclined tomographic planes are selected as partial images, and these partial images are combined to create a continuous image. By constructing , a panoramic image corresponding to an inclined tomographic plane can be obtained.

By making the above-mentioned inclined tomographic plane into a spherical shape or a similar shape, it is possible to select a tomographic plane that is inclined in accordance with both axes of the anterior tooth in a dental panoramic X-ray imaging device, and the periapical A panoramic image that focuses on the entire anterior tooth region from the crown to the crown can be obtained.

In addition, the innermost and outermost cylindrical tomographic planes that intersect with the inclined tomographic plane are detected according to the speed at which the target image moves in the continuous image information, and are selected from each panoramic image according to the results. By determining the position of the partial images, it is no longer necessary to measure the inclination angle of the inclined tomographic plane in advance, for example, using an X-ray photograph taken from the side.

<Example> Next, an illustrated embodiment will be described.

FIG. 1 is a block diagram of a basic embodiment of the apparatus of the present invention, in which 1 is an object, 2 is an XNA source, 3 is an xi image detection section, and 4 is a rotation device. In principle, the Xi output from the xg source 2 may be in the form of a cone beam, but if the
In order to reduce the exposure dose, it is necessary to use a slit beam shape, and in this embodiment, the X-ray source 2 is configured to output Xi in the form of a slit beam, similar to the conventional apparatus. The X-ray image detection unit 3 detects the
It converts an iO image into an electrical signal as a frame image with a certain area, and various devices known as X-ray image sensors can be used. For example, a fluorescent screen that converts XM into visible light and an image on the fluorescent screen can be used. SI T (Silic)
In addition to a high-sensitivity camera that takes images using an intensified tube (on an intensified tube), various other devices are used, such as an X-ray CCD sensor and an X-ray fluorescence multiplier. Swivel device 4
The X-ray source 2 and the X-ray image detection section 3 are integrally rotated around the subject 1, and the same one as in a conventionally known panoramic X-ray imaging apparatus can be used.

Reference numeral 5 denotes an image storage means, which stores, for example, V
Video signal recording devices such as TR1 optical disks and semiconductor storage devices such as large capacity DRAMs are used. Further, numeral 6 denotes a computer, which serves as an image processing means which is the central part of the present invention, and also serves as a control device to control the operation of the entire apparatus. 7 is a frame memory for storing a panoramic image obtained by image processing by the computer 6;
8 is an output unit that outputs the panoramic image as a visible image, and the output unit 8 is an image display device such as a CRT display or a liquid crystal panel, or an output device such as a printer that outputs a hard copy of the image. .

FIG. 2 is a flowchart showing the basic operating procedure of the device.

First, while driving the rotation device 4, X-rays are emitted from the Xi source 2, and the X-rays transmitted through the subject 1 are received by the X-ray image detection unit 3.
The obtained XMI image information is converted into an electrical signal of a frame image. This electrical signal has the same signal format as, for example, a television video signal, and is continuously recorded in the image storage means 5 at a rate of 30 images per second (step SL
). This frame image is a vertically elongated slit image corresponding to the slit beam of X-rays, and if the camera rotates half a circle around the subject 1 in 30 seconds, for example, a series of 900 frame images can be obtained. Note that the frame image is not a continuous signal like the above-mentioned video signal, but may be one that is intermittently photographed at short intervals and converted into an electrical signal.

Next, from a series of frame images continuously recorded in the image storage means 5, a take-out interval for selectively taking out frame images arranged at a time interval of Select a distance, that is, a shift amount, to add the image while shifting the position by a predetermined distance. At this extraction interval, take out the corresponding frame image in the form of digital enlightenment, and position it according to the selected shift claw. Addition processing is performed while shifting (step S3).The take-out interval and the shift book are arbitrarily selected. The resulting panoramic image is obtained by the above addition process.Then, in Step 7, the panoramic image is stored in the frame memory 7, and the resulting panoramic image is displayed on the output unit 8 or output as a hard copy (Step 7). 54).

Sl', No. 1 3' and S4' are examples of the outline of images obtained in the main steps.

A panoramic image of a specific tomographic plane can be obtained according to the take-out interval and shift amount as described in J-. In a conventional film-type panoramic X-ray imaging device, Although the principle is the same as that of obtaining a panoramic image of a specific tomographic plane by relative motion, the present invention selects the extraction interval and shift amount after imaging. Can you create a panoramic image of any tomographic plane? The difference is that it can be formed as appropriate.

FIG. 3 is a diagram illustrating this. That is, the X-ray beam 11 moves around the center of rotation 12 in the clockwise direction L.
1, the image of the object on the tomographic plane A consists of the X-ray beam 11 and the X-ray image detection unit 3 which is rotating.
is projected onto the X cotton plug exit surface 3f□1, and the X-ray detection surface 3a
,,,I:, 'i imaging device; 31] crosses from left to right when viewed from the side. Similarly, the image of an object on another tomographic plane A' is also X
It is projected on the cotton plug exit surface 3a and crosses in the same direction, but the center of rotation]2. The distance from the sleeve is so short that the movement speed when crossing is 1
4 faster than the image of tomographic plane A. Therefore, by selecting the moving speed LJ of these images, the extraction interval ``C'', and the shift angle, a panoramic image of the object on the tomographic plane A or A' synchronized with 1.T can be formed.

, -1, and if the take-out interval and the shift l-claw are constant, the curved shape of the tomographic plane will be an arc as shown in Figure 3, or
The extraction interval and shift amount do not have to be constant τ for one process, and can be changed in relation to the movement of the center of rotation of the X-ray beam. The fault plane can be selected.

Next, the procedure for obtaining a panoramic image corresponding to an inclined tomographic plane will be explained with reference to FIG. 4 and FIG. The figure is an explanatory diagram of image processing.
0 is a tilted fault direction that includes the tilted front tooth portion 15 and protrudes forward from the fault plane C in a substantially spherical shape, D, , C2..., L
) 4 is a cylindrical tomographic plane adjacent to tomographic plane C, C' is a panoramic image corresponding to tomographic plane C, D, ', one, '..., D
' is a partial image of the panoramic image corresponding to the tomographic planes, C2, . . ., D.

First, according to the procedure described in Fig. 2, images of transmitted X-rays of the dental arch, which is the subject, are taken, and the series of images are reproduced and extracted corresponding to the tomographic plane C in Fig. 5. The interval and shift amount are selected (step S1). In the reproduced image, images of each object through which the X-rays have passed are shown in a blurry state (although it is clever), and it is possible to know the moving speed of the target image. If we measure the velocity of the tooth image at , we can obtain a panoramic image of tomographic plane C.

It is possible to easily calculate the spacing and how many shift claws should be selected. The selected take-out interval and shift support are input to the combicoater 6 from the manual equipment fEt6a such as a Gi=-board. The inner and outer fault planes (,7
In the example, the take-out interval and shift number corresponding to (1) and (1) are selected (step S l 2). This selection is performed in the same manner as in the case regarding the above-mentioned tomographic plane C, by measuring the speed at which the images of the apical and crown parts of the anterior teeth 15 move in the reproduced image. can. In addition,
Since the root apex and the crown are at different positions with respect to the center of rotation of the X-ray beam, they move at different speeds in the reproduced image.

Next, based on the 7 extraction intervals and shift bases selected above, a panoramic image of each section J-bi plane is calculated by the combicoater 6, and the tomographic planes D,... l C4 is the tomographic plane C2.
The partial image of the famous panoramic image at the intersection with '
, D2'..., D,', and a partial image C' is obtained by removing each of these partial images from the panoramic image of the tomographic plane C (step 513). Then, as shown in FIG. 5(b), each partial image is added to the partial image C', ', D2',
..., by inserting and synthesizing D4',
A panoramic image is obtained by combining these images (step 514). (C) shows an example of a panoramic image formed in this way.

Although the tomographic plane C1 in the embodiment has a substantially spherical shape protruding from the tomographic plane C, it is also possible to select a tomographic plane having an uneven surface other than a spherical shape depending on the purpose and necessity. . Each fault plane, D,... is actually set in large numbers at minute intervals to obtain the required resolution, and the connection between fault planes C8 and C is made so that there are no sharp bends. programmed.

Note that since the root apex is in focus on the tomographic plane D1, the contrast of the root apex is better than that of other tomographic planes, and the contrast of the crown of the tooth is the best in the tomographic plane D4.

Therefore, it is also possible to automatically detect the tomographic plane D1 based on the quality of this contrast. Also, the fault plane...
Once D4 is determined and the position of the partial image is known, it is possible to approximately determine the position of the partial image on the tomographic plane between them using the linear interpolation method.

Note that this invention was made through research to improve a dental panoramic X-ray imaging device, so the above explanation has centered on the processing for obtaining a panoramic image of the dental arch. As mentioned above, the present invention can also be used in other fields, such as tomographic apparatuses for other parts of the human body and tomographic apparatuses for non-destructive testing of various objects.

<Effects of the Invention> As is clear from the embodiments described above, the present invention stores a transmitted xM image of a subject as a frame image, and then appropriately selects the image information retrieval interval and shift amount to create an arbitrary cylindrical tomographic image. A panoramic image of an image on a plane can be formed by digital processing, and a panoramic image corresponding to an image on a tomographic plane obliquely crossing a plurality of cylindrical tomographic planes is obtained.

Therefore, it is possible to obtain a panoramic image of the desired tomographic plane after imaging, and the various information obtained in one imaging is effectively used without being discarded, reducing the number of steps required for imaging. It is possible to select tomographic planes with shapes that were impossible with conventional devices and obtain panoramic images of them, making it possible to clearly reproduce even slanted anterior teeth as shown in the example, making it useful in clinical practice. A high-value device can be realized.

In addition, the innermost and outermost cylindrical tomographic planes that intersect with the inclined tomographic plane are detected according to the speed at which the target image moves in the continuous image information, and are selected from each panoramic image according to the results. In the case where the position of the partial image is determined, there is no need to measure the inclination angle of the inclined tomographic plane in advance, and the processing becomes easier.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the device of the present invention, and FIG.
Figure 3 is a flowchart showing the operating procedure of the device, Figure 3 is an explanatory diagram for selecting a tomographic plane, Figure 4 is a flowchart of the procedure for obtaining a panoramic image of an inclined tomographic plane in a dental panoramic X-ray imaging device, and Figure 5 The figure is an explanatory diagram of the operation. DESCRIPTION OF SYMBOLS 1...Subject, 2...X-ray source, 3...X-ray image detection section, 4...Swivel device, 5...Image storage means, 6...Computer, 7...Frame memo 1 C 11... X-ray beam, 12... Center of rotation, 15... Front teeth, A,
A'... Fault plane, C... Standard tom plane, C1... Inclined tom plane, D,, D,...l D4... Cylindrical tomographic plane, C', D,' , D,'...,D4'...
- Partial image of a panoramic image. Patent applicant Morita Seisakusho Co., Ltd. Sub-agent Patent attorney Shino 1) Actual purpose

Claims (3)

[Claims] (1) A rotating means for integrally rotating an X-ray source that is disposed facing each other with a subject in between and an X-ray image detection section that detects an image of the X-rays that have passed through the subject; image storage means for sequentially storing image information obtained by the image detection section as frame images; A surface image processing means that digitally forms a panoramic image of an image on an arbitrary cylindrical tomographic plane in accordance with the extraction interval and shift amount of each image information by adding the image information while shifting it by a predetermined distance. , and the image processing means selects images at predetermined positions as partial images from each panoramic image obtained for a plurality of cylindrical tomographic planes that overlap at minute intervals, and synthesizes these partial images. A digital panoramic X-ray imaging apparatus characterized in that it is configured to obtain a panoramic image corresponding to an image on a tomographic plane that obliquely crosses the plurality of cylindrical tomographic planes. (2) The digital panoramic X-ray imaging apparatus according to claim 1, wherein the tomographic plane that obliquely crosses the plurality of cylindrical tomographic planes has a spherical shape or a shape similar to this. (3) Among the plurality of cylindrical tomographic planes, the innermost and outermost tomographic planes that intersect with the oblique tomographic plane are detected, respectively, based on the speed at which the target image moves in continuous image information. 2. The digital panoramic X-ray imaging apparatus according to claim 1, wherein the position of the partial image to be selected from each panoramic image is determined in accordance with the results of the determination.