JP6595480B2 - Generating dental panoramic images - Google Patents

Description

  The present invention relates to dental panoramic imaging, and more particularly to generating a dental digital panoramic image from multiple frame images acquired during a dental panoramic imaging scan around a patient's head. .

  In the conventional operating principle of a panoramic X-ray device, an X-ray source is moved around the patient's head while moving the film relative to the X-ray beam so that the dental arch is taken as a planar photo on the film. And drive the film cassette.

  This basic operation of conventional dental panoramic imaging forms a mutual movement between the X-ray source, the image information receiver, and the patient. There are several possible ways to create such movement, but the most common method is to attach the X-ray source and image information receiver to the support arm at a distance from each other and In contrast, the support arm is moved in a unique manner. In such a method, in order to obtain a clear image of the desired layer in the subject (ie, the layer of the dental arch in the patient's head), the speed at which the film is moved and along the desired layer to be photographed. The X-ray beam sweep rate must be clearly related. In this way, unwanted structures in front of and behind the desired layer in the patient's head are not blurred.

  In this conventional panoramic photography, the thickness of a clearly photographed layer is directly proportional to the distance from the film surface to the instantaneous center of rotation of the support arm, and inversely proportional to the magnification and beam width.

This basic equation for panoramic photography can be expressed as:
v1 / v0 = L1 / L0
v0 = ωr
In these equations,
L0 is the distance L1 from the focal point F of the X-ray tube to the point of the subject to be imaged at a specific moment, and the distance ω from the focal point F of the X-ray tube to the surface of the X-ray film (or detector) is The angular velocity r of the rotational motion around the instantaneous center of rotation is the distance v1 from the instantaneous center of rotation to the point of the subject to be photographed, the speed of the image point on the film (detector) surface.

  Thus, the speed v1 is related to the speed at which the film is moved relative to the X-ray beam incident on the film during a panoramic scan. With respect to digital photography, when so-called TDI (Time Delay Integration) photography technology is used, the pixel charge transfer rate across the detector is associated with the speed at which the film is moved. Therefore, when the scanning process and charge transfer are performed so as to follow this imaging equation, the image data read from the sensor corresponds to a panoramic film image in the sense that the layer outside the desired layer is already blurred. In this case, regarding the selection of the tomogram shown in the image, post-irradiation image processing is not only necessary but actually impossible, because the data read from the sensor already represents the desired layer corresponding to the velocity v1. This is because.

  Furthermore, the conventional digital panoramic photography includes a so-called FT (frame transfer) technique. When using FT technology, or other technology where multiple individual overlapping frames are taken during a scan, you can see clearly when you want to see the same layer as obtained according to the traditional panoramic equation presented above The degree of frame overlap when constructing the layer to be associated is associated with the velocity v1.

  One advantage provided by the frame transfer technique is that the layer that is relatively emphasized while the other layers are blurred is determined by the degree of overlap of the frames used during image processing, so changing the degree of overlap The tomography can be changed to some extent after irradiation. The degree to which the layers can be changed depends on the method used and the means used. In general, however, the position of the layers can only be changed slightly.

  Nevertheless, in the prior art frame panoramic system, it is possible to change the sharp layer slightly, and the degree of overlap used at the time of image construction is based on some predetermined scheme . Such predetermined schemes typically use a standard overlap of frames, and the actual calculation of the panoramic image does not involve anything related to the actual imaging geometry of the imaging system at the illumination position of the frame. This parameter is also not included.

  Furthermore, the viewing direction of the tissue structure is determined by the imaging arrangement used to acquire the frame data (ie, the imaging means (X-ray source and image information receiver) when acquiring the frame data). In the prior art system, the viewing direction is fixed because there is no means to change the viewing direction in which the panoramic image or part thereof is displayed.

  In addition, frame imaging techniques are fast enough during an imaging scan, even when using a wider detector area than is actually possible when using traditional continuous scanning techniques. There is a reference condition that the frame needs to be able to be read or the magnification rate does not change significantly within one frame, and this allows the detector width that can be actually used in conventional dental frame panoramic photography. Has also been limited.

  The main objective of the present invention and its preferred embodiments is to provide a new possible method for generating dental panoramic images from frame data after irradiation, to obtain frame image data acquired in a single panoramic scan, It is to provide a system that can be used in relation to information on the actual shooting arrangement used in the shooting procedure for each irradiation position. Another object of the present invention is not only to generate two or more slices from frame image data acquired in one panoramic scan, but also to multiple images of a dental arch viewed from multiple different directions. Alternatively, it is possible to construct and display partial images.

  The above objects of the invention and other objects described below can be achieved by embodiments of the invention as defined in the appended claims. The central idea of the present invention is that the radiographic arrangement information at the irradiation position (ie the position and orientation of the detector and the focal point of the X-ray tube and hence the focal point of the X-ray beam) is known. This information is used when performing a panoramic scan and then calculating a dental panoramic image.

  Various embodiments of the present invention make it possible to generate a dental panoramic image viewed from more than one direction from a single frame data set, which is advantageous. When it is possible to virtually change the viewing angle, the shape of the tissue structure that is not visible from another viewing direction can be made visible. Therefore, for example, it is possible to avoid X-ray irradiation to the patient again because it is necessary to retake an image. Furthermore, in the embodiments described below, it is possible to use a detector wider than that commonly used in dental frame panoramic photography.

  In the following, the invention and some of its preferred embodiments will be described with reference to the accompanying drawings.

1 shows an example of a panoramic photographing apparatus. Some of the basic components of a system for implementing the embodiments described below are shown. FIG. 3A shows a dental panoramic image, and FIG. 3B shows individual frame images, from which a dental panoramic image can be generated. Individual overlapping frames and lines representing the vertical portion of the tissue structure are shown, and the vertical portion is projected to different positions in the frame as the imaging detector moves to a new illumination position. FIG. 2 shows a schematic diagram of the principle of a panoramic imaging process according to an embodiment of the present invention. Fig. 4 shows a series of steps of a method applying the principles of the present invention. 1 shows a schematic diagram illustrating the hardware configuration of an information processing / computer system that can be used when implementing the present invention.

  In the following, the embodiments described herein, as well as their various features and advantageous details, are shown in the accompanying drawings and detailed in the following description to limit the invention. A more complete description will be given with reference to the non-existent embodiments. Descriptions of well-known components and processing techniques have been omitted so as not to unnecessarily obscure the embodiments herein. The examples used herein facilitate an understanding of how the embodiments herein can be implemented and enable those skilled in the art to implement the embodiments herein. Only for the purpose. Accordingly, these examples should not be construed as limiting the scope of the embodiments herein.

  Further, it should be understood that the embodiments are exemplary. For example, reference to “an embodiment”, “one embodiment”, or “some embodiments” in this specification does not necessarily refer to each same embodiment, and A feature does not necessarily apply to only one embodiment. Even if not explicitly disclosed in context, one feature of each of a number of different embodiments may be combined to provide another embodiment.

  In the embodiments of the invention described herein, dental panoramas are used using X-ray beam and X-ray detector position and orientation information when imaging overlapping frames along the dental arch. Generate an image. For example, in the embodiments described below, a user can view a particular region of interest of the dental arch from an angular range (ie, from more than one viewing direction). Thus, in the embodiments described herein, the user can see certain shapes between the patient's teeth in a dental panoramic radiograph, which shapes are used, for example, using prior art methods and devices. May not be visible in another dental panoramic radiograph that is generated.

  FIG. 1 of the accompanying drawings shows the structure of an exemplary panoramic X-ray imaging apparatus. This device includes a base 27 and a columnar support structure 12 fixed to the base 27 by a lower end. The support arm 13 (shown with its cover removed) is rotatably attached to the upper end of the support structure 12. Similarly, another intermediate support arm 14 is rotatably attached to the outer end portion of the support arm 13, and a photographing arm 15 (often referred to as a C arm) is further attached to the outer end portion of the intermediate support arm 14. Is mounted rotatably. The C arm 15 supports imaging means (that is, the X-ray source 26 and the image detector 16). Furthermore, a positioning support body 25 for supporting positioning of a patient to be imaged is attached to the columnar support structure portion 12. Instead of being attached to the columnar support structure 12, the rotatable support arm 13 can also be attached to a wall or ceiling structure.

  The structure shown in FIG. 1 is simplified for clarity. For example, force receiving means that serve as force transmitting means of the arm structures 13, 14, 15 are not shown in this figure. Similarly, the stepping motor 1 for rotating the arm structures 13, 14, 15 is shown in a simplified form.

  The apparatus shown in FIG. 1 and its control system (not shown in FIG. 1) move the center of rotation of the C-arm 15 carrying the imaging means so that basically any desired shape of the center of rotation is obtained. FIG. 6 illustrates an example of a structure for performing a panoramic scan around a patient's head using a trajectory. The structure of the dental panoramic imaging device varies, and the simplest imaging device can use only one fixed imaging arrangement.

  As shown in FIG. 2, the basic components of the system for carrying out the present invention include a control system CS for an imaging apparatus, which is a single arm or arm 13 of the apparatus. , 14, and 15, and is operatively connected to the motor 1, and is further operatively connected to operating electronics of the detector 16. In particular, the system includes a memory M that records frame image information and related information relating to shooting arrangement, a processing means IP that generates a panoramic image, a screen S that displays an image, and a user interface UI.

  FIG. 3A shows a typical dental panoramic image 200. FIG. 3B shows one of hundreds to thousands of frame images 300 partially overlapped acquired at the time of scanning when constructing the digital panoramic image 200 from the frame image data acquired at the time of panorama shooting scanning. Can be considered. FIG. 4 illustrates the principle of the method of using the overlapping individual frames 310, 315, 320 acquired during the panoramic scan when constructing the digital panoramic image 200. A line 210 penetrating the frames 310, 315, and 320 in the vertical direction represents the position of a pixel column in each frame including image information of the same thin vertical portion of the tissue structure to be imaged. As will be described in more detail later, the image information contained in these pixel columns is used to construct the pixel column C of the final digital panoramic image 200 to be generated. Frames taken before frame 310 and after frame 320, i.e., frames that do not intersect line 210 and thus do not contain information about a particular portion of the tissue structure that line 210 represents, are identified in panoramic image 200 to be generated. Does not contribute to the pixel column C.

  FIG. 5 shows a schematic diagram for explaining the principle of the panoramic photographing process of the present invention. In this process, a curve referred to as a virtual panoramic curve 400 in this specification and data on the position and orientation of the imaging means at the time of irradiation in the coordinate system of this curve are used. In other words, as will be described in more detail later, in this process, the virtual panoramic curve 400 representing the position and shape of the generated tomography is placed in the coordinate system of the shooting arrangement used when shooting the frame data.

  FIG. 5 shows a plurality of points (P1, P2, P3, P4) on the virtual panoramic curve 400, and each point corresponds to the position of the portion of the tissue structure shown in the panoramic image. Can think. In other words, each point (P1, P2,...) Represents the position of the vertical layer of the dental arch, shown as an individual pixel row in the generated digital panoramic image.

Further, FIG. 5 shows two irradiation positions, that is, the position (E ′, E ″) of the X-ray source at the time of irradiation and the position of the detector at the time of irradiation (thus penetrating the tissue structure to be imaged). The position of the incident X-ray beam). When the photographing arrangement is known, the position of the projection P ′ on the detector at each point P at each irradiation position where the projection P ′ is incident on the detector can be obtained. These projection point P 'determines the pixel rows on the detector that is used when building columns C of the panoramic image, column C represents a particular point P _N of organizational structure, the projection P → P' Can be thought of as defining the projection direction of point P in a particular individual frame 300.

  As can be seen in FIG. 5, at the first illumination position E ′, the projection P′2 of the point P2 as seen from the focal point of the radiation source is incident on the detector (frame) at a position far from the center of the detector. However, at the second position E ″, the projection P ″ 2 is essentially incident on the center of the detector. This is a situation that is overlooked in the prior art image construction process when adding overlapping frames of a sequence by some standard predetermined procedure, but in the embodiments described herein, a panoramic image is constructed. It is possible to select a column to be used when performing shooting based on the actual information of the shooting arrangement. In other words, instead of simply adding overlapping frame column information according to some standard addition procedure, any particular point P1, P2 when viewed from the instantaneous position of the focus of the X-ray beam at the time of imaging. ,. . These columns are used particularly when calculating the column C of the panoramic image to be generated by obtaining specific columns of the respective frame images where the projections are located.

  By changing the shape and / or orientation of the panoramic curve 400 by knowing the imaging arrangement (ie, the position and orientation of the x-ray source and detector during the imaging scan), multiple different layers of tissue structure In addition to calculating itself, it is also possible to construct and display layers of the subject viewed from a plurality of different directions. This feature of the present invention can be understood by considering slightly rotating the panoramic curve 400 of FIG. 5 counterclockwise about point P4. Considering the imaging positions E ′ and E ″, this causes the projections P′2 and P ″ 2 to move to the left on the detector (on the frame, as seen from the direction of the focus of the X-ray source). Therefore, different pixel column information used when constructing the panoramic image is selected. These different pixel columns not only represent a layer different from the layer according to FIG. 5, but also represent different viewing angles of the subject.

  In principle, it is possible to use a virtual panoramic curve having an arbitrary shape arranged in an arbitrary direction in a coordinate system arranged at the time of photographing. This makes it possible to build a fault having a shape that cannot be generated even by the very general purpose device of FIG. 1 by mere mechanical movement of the arm structure of the device.

  As a further aspect, any number of points P1, P2,. . In contrast, individual local line-of-sight vectors D can be determined. FIG. 5 includes a vector D representing a desired local line-of-sight direction of the point P2 in addition to the contents described above with reference to this figure. Such a vector D is a specific point P1, P2,. . Can be used for the purpose of obtaining a weighting factor for the pixel value of the column in the frame. For example, as can be seen in FIG. 5, the angle between the projection direction defined by the line starting from the focal point of the radiation source and ending at the projection point P ′ and the vector D is the first irradiation position E in FIG. It is somewhat larger at the second irradiation position E '' than at '. When this type of embodiment is applied, when constructing the image, the pixel value in the column of the projection point P ″ 2 of the second irradiation is more than the value of the projection point P′2 of the first irradiation. Give small weights. When this principle is applied to the projection P ′ of the point P (ie, when a pixel value in a specific projection direction is given a higher weight than other pixel values), the shape of the tissue structure viewed from the preferred direction Is emphasized.

  The flowchart shown in FIG. 6 illustrates one preferred method for implementing the principles of the present invention. In the first step 500 of the method of FIG. 6, the frame and the respective illumination position of the frame during the panoramic scan that has been performed are read. Next, in step 510, a virtual panoramic curve to be used when constructing the image is generated, and in step 520, the curve is divided into a plurality of points P, that is, in other words, an organization corresponding to the column C of the generated panoramic image. A plurality of points P defining the position of the structure are selected from this curve (preferably equally spaced). In step 530, the individual line-of-sight directions D at point P can be determined.

  Actually, taking into account the shooting arrangement used in the panoramic shooting scan, the imaging arrangement makes it possible to reasonably generate the desired layer or layers as described above. Preferably, one or more virtual panoramic curves 400 that are to be used when constructing are recognized.

  Since all the data has been prepared at this point, generation of the column C of the panoramic image 200 to be constructed can be started (step 540). Initially, at step 550, a point P corresponding to column C of the panoramic image and an associated local line-of-sight direction D (if such a line-of-sight direction D at point P is determined) are identified. Since the panoramic curve 400 and the position and orientation of each frame and radiation source at the time of irradiation of each frame are known, the following process can be performed for each frame (step 560). In this process, first, in step 570, a point P is projected onto the frame along a line starting from the focal point of the radiation source. In practice, in most frames, there is no projected point P ′ because the line starting from the focus of the X-ray source and passing through the point P on the panoramic curve does not intersect, but in the remaining few frames The point P ′ projected onto the frame defines the pixel sequence of that particular frame that is used when constructing the sequence C of the panoramic image represented by the point of interest P (step 580 and step 610). .

  If the local line-of-sight direction D at a given point P has been determined, then in step 590, the local line-of-sight direction D and the line passing through the point of interest P starting from the focal point of the X-ray source. Find the angle between. This angle can be used as a weighting factor in step 600, and the projection direction of the point P (in other words, the vector from P to P ′ with reference to FIG. 5) is larger than the desired local line-of-sight direction D. The more deviating, the less weight is given to the frame (ie to the pixel value of the projection point P ′ of the frame) in the image construction (step 610). After this process is complete (step 620), the pixel value in each column C of the final panoramic image is normalized by dividing the value in column C by the sum of the weighting factors for that column.

  The procedure described above can be presented more generally as follows: using several individual overlapping frames 300 taken along the dental arch by a dental panoramic radiograph. A dental panoramic X-ray apparatus comprising an X-ray source for generating an X-ray beam and having a focal point, and an image detector having a pixel array; An X-ray beam at the time of imaging of the frame, comprising: taking an image detector around the patient's head; and calculating a panoramic image 200 by adding the information of the frame 300 The panoramic image 200 is generated by adding the information of the frame 300 based on the position and orientation information of the X-ray detector. In this case, the step of adding information includes the step of obtaining the position of one or more desired points P in relation to information on the position and orientation of the X-ray beam and the X-ray detector at the time of imaging the frame. The step of adding the information of the frame 300 may include the step of adding one or more columns C of the panoramic image 200 corresponding to the one or more points P. Meanwhile, at least two panoramic images 200 viewed from a plurality of different directions are generated, and at least two images representing views from a plurality of different directions are displayed on the display simultaneously or sequentially. Or as a composite image or as a moving image.

  According to one embodiment, generating a virtual panoramic curve 400 representing a tomogram represented by the panoramic image 200, and the information about the position and orientation of the X-ray beam and the X-ray detector in the same coordinate system. The method may further include placing and generating a panoramic image 200 representing a tomogram according to the position of the curve 400 in the coordinate system.

  According to yet another embodiment, generating a virtual panoramic curve 400 representing a desired tomogram represented by the panoramic image 200 in relation to the position and orientation information of the X-ray beam and X-ray detector; A panoramic image is obtained by adding the desired point P on the curve 400 corresponding to the column C of the image 200 and the column of individual frames 300 onto which the point P is projected as seen from the focal point of the radiation source. Generating 200 columns C, wherein the projection P → P ′ defines the projection direction of the point P in a particular individual frame 300.

  With regard to the weighting factor, an associated process can be presented to include determining a desired gaze direction D at at least one point P. In this case, the weighting factors for the columns on the individual frames 300 are calculated based on the angle between the direction defined by the line from the focal point of the radiation source to the point P and the line-of-sight direction D, and the frame 300 information. The greater the angle between this direction vector D representing the desired line-of-sight direction and the direction defined by the line from the focal point of the radiation source to the point P, the less weight is given to the column of frames. Use a weighting factor as

  Think of the virtual panoramic curve used in the embodiment described above as a tool that allows to change the tomography in a controlled manner based on the shooting-time arrangement used when acquiring frame data Furthermore, the virtual panoramic curve can be used for the purpose of changing the direction of viewing the tissue structure or a part thereof. By changing the shape and / or orientation of the virtual panoramic curve and applying the local gaze direction vector described above to the same set of original X-ray frame image data acquired in a single panoramic scan Based on this, multiple different images of the dental arch can be constructed.

  The virtual panoramic curve 400 used when generating a panoramic image can be defined in various ways. As one preferred method, first, a curve that satisfies the basic equation of panoramic photography described above concerning the movement of the photographing means is generated. Since the movement of the imaging means in a particular type of panoramic imaging device is often constant, or several same standard movements are commonly used, a panorama curve 400 corresponding to a particular imaging procedure is generated and later It can be stored for use. Furthermore, the previously used or stored virtual panorama curve or the now used virtual panorama curve can be modified, for example by means including a linear transformation of all points P and the associated gaze direction. This linear transformation can include a rotating portion and a translating portion. Furthermore, this modification can also use a non-linear mapping function such as a two-dimensional spline curved surface that can be used to deform the panoramic curve.

  Embodiments of the present invention include a novel method for displaying a dental panoramic image on a display as well as generating the dental panoramic image itself, as described above. For example, when the information on the position and orientation of the X-ray beam and the X-ray detector at the time of imaging the frame is available, the frame information is different based on the information on the position and orientation of the X-ray beam and the X-ray detector. By adding the conditions, it is possible to generate two or more panoramic images viewed from a plurality of different directions, whereby a plurality of images viewed from a plurality of different directions are displayed on the display, for example simultaneously or It can be displayed continuously, as a composite image, or as a moving image.

  For example, a first virtual panorama curve and a second virtual panorama curve can be generated in relation to the position and orientation information of the X-ray beam and the X-ray detector, both curves being shown by the panoramic image. The second curve representing the desired layer is generated from the first curve by changing the orientation of the first curve. Then, two panoramic images are calculated by adding the frame information acquired in the panoramic photographing process based on these different curves. Of course, more than two curves can be used. For example, the illusion of rotating the dental arch can be created by continuously displaying a plurality of panoramic images with different gaze directions. In other words, in this type of embodiment, multiple images can be continuously displayed on the display according to their visual line order so that the dental arch appears to rotate on the display.

  According to a further embodiment, generating several panoramic images viewed from a plurality of different directions and generating several images representing a plurality of different sharp layers for each such gaze direction And can be included. Then, for each such line-of-sight direction, one of the images representing the line-of-sight direction can be selected from among several images representing different distinct layers, and then selected in this way. The plurality of rendered images can be displayed on the display as described above, for example, simultaneously or sequentially, as a composite image, or as a moving image.

  By using the weighting factor as described above, the effect of multiple different viewing angles is enhanced by more emphasizing columns that have a primary X-ray movement path that matches the viewing angle of the panoramic curve at a given point P. be able to.

  Furthermore, the use of weighting factors makes it possible to use a wider detector plane than is commonly used in dental frame panorama applications. When the method of summing frame data in the prior art is based on some standard superposition procedure, the farther the columns that are summed together are away from the center of the detector, the more these columns represent the same part of the tissue structure. Most likely not. This is due to the fact that the exact change in the overall shooting arrangement during the irradiation process (ie the change in the position and orientation of the desired layer to be generated and the imaging means) is not recognized in the addition procedure. However, using the principles described herein, it can be avoided that the panoramic image is blurred due to adding information representing different positions of the tissue structure to the column C of the panoramic image 200. Furthermore, weighting factors can be used for the purpose of correcting the changing magnification.

  With respect to embodiments of the present invention, as one possible way to create the illusion of rotating the imaged tissue structure, a single virtual panoramic curve is used and the local gaze direction vector D of the point P described above is used. Various panoramic images are generated on the basis of the virtual panorama curve by systematically changing the orientation of. In general, with respect to displaying captured tissue structures based on frame data acquired in a single panoramic scan, the scope of the present invention includes multiple different layers of tissue structures, and multiple Modifying the virtual panoramic curve 400 to display the tissue structure from different viewing angles, or any of these, and modifying the orientation of the local direction vector D of the point P (a selected number of It is clear that any combination of (including modifying only the vector D) is included.

  In the embodiments described herein, dental frame panoramic imaging can be used to implement an embodiment of a dental panoramic imaging device that has a focused X-ray. An image detector having a source and a plurality of pixel columns, the X-ray source and the image detector being arranged in the apparatus at a first distance from each other; Drive means moving around the part and a control system including means for controlling the apparatus to image several individual overlapping frames along the dental arch. The detector can be implemented to have a width equal to or greater than the second distance, and the control system controls the apparatus to image a frame having a width equal to the second distance. The second distance is about 2-10% of the first distance. In one embodiment, the distance between the X-ray source and the image detector is preferably about 500-550 mm.

  As described above, in the embodiments described herein, it is further possible to display tissue structures that can only be viewed with other devices at least through a further panoramic irradiation process on the patient. When the line-of-sight angle can be changed, details of the imaged tissue structure that would otherwise be visible can be made visible. For example, the tooth filling may make the tooth on the opposite side of the dental arch invisible, but such a tooth can be made visible by changing the viewing direction.

  FIG. 7 shows a schematic diagram illustrating the hardware configuration of an information processing / computer system capable of implementing an embodiment of the present invention. The system 1000 of FIG. 7 includes at least one processor or central processing unit (CPU) 1010. The CPU 1010 is interconnected via a system bus 1012 to various devices such as a random access memory (RAM) 1014, a read only memory (ROM) 1016, and an input / output (I / O) adapter 1018. The I / O adapter 1018 can be connected to a peripheral device (disk unit 1011, tape drive 1013, etc.) or other program storage device readable by the system 1000. The system 1000 can read instructions related to the present invention in the program storage device and execute the methods of the embodiments herein according to these instructions. In addition, the system includes a user interface adapter 1019, which collects user input, such as a keyboard 1015, a mouse 1017, a speaker 1024, a microphone 1022, and other user interface devices (touch screen devices (not shown)). Or the like) is connected to the bus 1012. In addition to these, the communication adapter 1020 connects the bus 1012 to the data processing network 1025, the display adapter 1021 connects the bus 1012 to the display device 1023, and the display device 1023 includes, for example, a monitor, a printer, It can be embodied as an output device such as a transmitter.

  Therefore, a further embodiment is a dental panoramic imaging apparatus, which is an X-ray source having a focus and an image detector having a plurality of pixel columns, arranged in the apparatus at a distance from each other, Control the apparatus to image several individual overlapping frames along the dental arch, with a source and image detector, drive means for moving the X-ray source and detector around the patient's head A control system including means and a user interface for sending control commands to the control system, wherein the control system records the position and orientation of the X-ray source and X-ray detector at the time of taking a frame. To generate a panoramic image viewed from at least two different directions, the frame information is added based on the information to generate a panoramic image. Means for calculating a macro image, and wherein the user interface includes means for inputting at least one control command related to displaying at least two panoramic images viewed from at least two different directions. , Dental panoramic imaging device.

  A dental panoramic imaging device having the structural features of the above paragraph is a control system or image processing function or other related to acquiring and constructing an image according to any embodiment described herein. It can also be used to include functionality, or both.

  The above description of the specific embodiments will fully reveal the general characteristics of the embodiments herein, so that the present invention can be applied in various applications by applying the description provided herein. Such specific embodiments can be easily modified and / or adapted without departing from the general idea of It is intended to be included within the spirit and scope of the equivalent forms of the disclosed embodiments. It should be understood that the expressions and terminology used herein are for the purpose of explanation and do not limit the invention. Accordingly, although the embodiments herein are described based on preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims. Will be understood.

Claims (18)

A method for generating a dental digital panoramic image comprising:
Using a number of individual overlapping frames (300) taken along the dental arch by a dental panoramic radiographing device, the dental panoramic radiographic device comprising:
An X-ray source (26) for generating an X-ray beam and having a focus;
An X-ray detector (16) for detecting the X-ray beam ;
The frame (300) is imaged by moving the X-ray source (26) and the X-ray detector (16) around the patient's head;
-Calculating the panoramic image (200) by adding the information of the frame (300);
Including
- by adding the information of the frame (300) based on the position and orientation information of the X-ray source (26) and said X-ray detector at the time of photographing the frame (300) (16), wherein A panoramic image (200) is generated ,
One or more desired points (P) in relation to the information of the position and orientation of the X-ray source (26) and the X-ray detector (16) at the time of imaging the frame (300). And the step of adding the information of the frame (300) includes one or more pixel columns (C) of the panoramic image (200) corresponding to the one or more points (P) Adding, and
A desired line-of-sight direction (D) at at least one point (P) is determined and a weighting factor for a pixel column on an individual frame (300) is determined from the focal point of the X-ray source (26) to the point (P) Calculated based on the angle between the direction defined by the line up to and the line-of-sight direction (D),
-When adding the information of the frame (300), defined by the direction vector (D) representing the desired line-of-sight direction and the line from the focal point of the X-ray source (26) to the point (P) The weighting factor is used so that the greater the angle between the direction and the smaller the weight is given to the pixel columns of the frame,
Method. A virtual panoramic curve (400) representing a tomogram represented by the panoramic image (200) is generated, and the position of the virtual panoramic curve (400), the X-ray source (26) and the X-ray detector (16) ; And the information of the orientation are placed in the same coordinate system,
The panoramic image (200) representing a slice is generated according to the position of the virtual panoramic curve (400) in the coordinate system;
The method of claim 1 . A virtual panoramic curve (400) representing a desired tomographic image represented by the panoramic image (200) is associated with the information of the position and orientation of the X-ray source (26) and the X-ray detector (16) ; Generated
-The desired point (P) on the virtual panoramic curve (400) corresponding to the pixel column (C) of the generated panoramic image (200) is determined;
The pixel column (C) of the panoramic image (200) by adding the pixel columns of the individual frames (300) onto which the point (P) is projected as viewed from the focal point of the X- ray source (26) ; Is generated, and the projection (P → P ′) defines the projection direction of the point (P) in a particular individual frame (300),
The method according to claim 1 or claim 2 . By dividing the given pixel column pixel value (C) by the sum of the weight coefficient of the pixel column, the pixel value of the final pixel row of the panoramic image (200) (C) are normalized A method according to any of claims 1 to 3 . A method for generating and presenting a dental digital panoramic image comprising:
Using a number of individual overlapping frames (300) taken along the dental arch by a dental panoramic radiographing device, the dental panoramic radiographic device comprising:
An X-ray source (26) for generating an X-ray beam and having a focus;
An X-ray detector (16) for detecting the X-ray beam ;
A display functionally connected to the dental panoramic X-ray apparatus;
And wherein the frame (300), said X-ray source (26) and said X-ray detector (16) is photographed by moving around the patient's head, comprising the steps,
-Calculating the panoramic image (200) by adding the information of the frame (300);
Presenting on the display the panoramic image (200) of the tomogram thus generated;
Including
-By adding the information of the frame (300), at least two panoramic images (200) viewed from different directions are generated;
-The at least two panoramic images (200) representing the field of view from different directions are successively displayed according to the order of their gaze directions so that the dental arch appears to rotate on the display. shown Hisage on said display,
Method. The step of generating the at least two panoramic images (200) comprises:
Based on the position and orientation information of the X-ray source (26) and the X-ray detector (16) at the time of imaging the frame (300), the information of the frame (300) is obtained under at least two different conditions. The step of adding,
including,
The method of claim 5 . -Several panoramic images (200) viewed from different directions are generated,
-For each such line-of-sight direction, several images representing multiple different slices are generated,
-For each such line-of-sight direction, one image representing the line-of-sight direction is selected from among the several images representing a plurality of different slices;
-The image thus selected is presented on the display;
7. A method according to claim 5 or claim 6 . The step of generating the panoramic image (200) is based on the position and orientation information of the X-ray source (26) and the X-ray detector (16) at the time of capturing the frame (300). Adding the information of the frame (300),
In relation to the information on the position and orientation of the X-ray source (26) and the X-ray detector (16) at the time of imaging the frame (300), the position of the desired point or points P is determined. The step of determining and adding the information of the frame (300) includes one or more pixel columns (C) of the panoramic image (200) corresponding to the desired one or more points (P); A method according to any of claims 5 to 7 , comprising the step of adding. A virtual panoramic curve (400) representing the tomographic image shown in the panoramic image (200) is generated, and the position of the virtual panoramic curve (400), the X-ray source (26) and the X-ray detector (16) ; And the information of the orientation are placed in the same coordinate system,
-Adding the information of the frame (300) based on the virtual panorama curve (400) such that the virtual panorama curve (400) is arranged in at least a first orientation and a second orientation in the coordinate system; To generate the at least two panoramic images (200) viewed from a plurality of different directions, and for each of the orientations:
-The desired point (P) on the virtual panoramic curve (400) corresponding to the pixel column (C) of the generated panoramic image (200) is determined;
The pixel column (C) of the panoramic image (200) by adding the pixel columns of the individual frames (300) onto which the point (P) is projected as viewed from the focal point of the X- ray source (26) ; Is generated, and the projection (P → P ′) defines the projection direction of the point (P) in a particular individual frame (300),
The method according to any one of claims 5 to 8 . A dental panoramic imaging device,
An X-ray source (26) for forming an X-ray beam and having a focus, and an X-ray detector (16) for detecting the X-ray beam , arranged at a distance from each other in the dental panoramic radiography apparatus The X-ray source (26) and the X-ray detector (16);
- a drive means for moving the X-ray source (26) and said X-ray detector (16) around the patient's head (1),
A control system (CS) comprising means for controlling said dental panoramic imaging device to image several individual overlapping frames (300) along the dental arch;
A user interface (UI) for sending control commands to the control system (CS);
With
The position and orientation information of the X-ray source (26) and the X-ray detector (16) at the time when the control system (CS) images the frame (300) and at least two different directions; Generating a panoramic image (200) by adding information of the frame (300) based on the position and orientation information to generate a panoramic image (200),
- the user interface (UI) is seen containing a means for inputting at least one control command related to showing the panoramic image (200) as viewed from the at least two different directions,
-The control system (CS) comprises means for continuously presenting the panoramic images (200) according to their gaze order so that the dental arch appears to rotate;
Dental panoramic imaging device. The control system (CS)
Based on the position and orientation information of the X-ray source (26) and the X-ray detector (16) at the time of imaging the frame (300), the information of the frame (300) is obtained under at least two different conditions. Means (IP) for generating said at least two panoramic images (200) by adding,
including,
The dental panoramic imaging apparatus according to claim 10 . Said means (IP) for calculating a panoramic image (200),
Means for adding the information of the frame (300) based on the position and orientation information of the X-ray source (26) and the X-ray detector (16) at the time of imaging the frame (300);
including,
The dental panoramic imaging apparatus according to claim 10 . Said means IP for calculating a panoramic image (200) comprises:
Generating a virtual panoramic curve (400) representing a tomogram indicated by the panoramic image (200), the virtual panoramic curve (400), the positions of the X-ray source (26) and the X-ray detector (16); Means for placing the information of orientation in the same coordinate system and generating the panoramic image (200) representing a slice according to the position of the virtual panoramic curve (400) in the coordinate system;
including,
The dental panoramic imaging apparatus according to claim 12 . Said means (IP) for calculating a panoramic image (200),
A virtual panoramic curve (400) representing a desired tomogram represented by the panoramic image (200) is generated in relation to the information of the position and orientation of the X-ray source (26) and the X-ray detector (16). Then, a desired point (P) on the virtual panoramic curve (400) corresponding to the pixel row (C) of the generated panoramic image (200) is obtained and viewed from the focus of the X- ray source (26). Means for generating a pixel column (C) of the panoramic image (200) by adding the pixel columns of the individual frames (300) onto which the point (P) is projected. Said means, wherein P ′) defines the projection direction of said point (P) in a particular individual frame (300);
including,
The dental panoramic imaging apparatus according to claim 12 or 13 . A dental panoramic imaging device,
An X-ray source (26) for generating an X-ray beam and having a focal point, and an X-ray detector (16) for detecting the X-ray beam, the dental panoramic imaging device at a first distance from each other; The X-ray source (26) and the X-ray detector (16),
Driving means (1) for moving the X-ray source (26) and the detector (16) around the patient's head;
A control system (CS) comprising means for controlling said dental panoramic imaging device to image several individual overlapping frames (300) along the dental arch;
With
-The control system (CS) includes information on the position and orientation of the X-ray source (26) and the X-ray detector (16) at the time of imaging the frame (300), and information on the position and orientation. Means (IP) for calculating a panoramic image (200) by adding the information of the frame (300) based on the panoramic image (200) so that the dental arch appears to rotate. Continuously presenting according to the order of their gaze directions ,
The X-ray detector (16) is implemented to have a width equal to or greater than the second distance;
- said control system, said being adapted to control the dental panoramic imaging device to capture a frame (300) having a second width equal to the distance, the second distance is, the first About 2-10% of the distance of
Dental panoramic imaging device. The dental panoramic imaging apparatus according to claim 15 , wherein the first distance is about 500 to 550 mm. Said means (IP) for calculating a panoramic image (200),
Generating a virtual panoramic curve (400) representing a tomogram indicated by the panoramic image (200), the virtual panoramic curve (400), the positions of the X-ray source (26) and the X-ray detector (16); Means for placing the information of orientation in the same coordinate system and generating the panoramic image (200) representing a slice according to the position of the virtual panoramic curve (400) in the coordinate system;
including,
The dental panoramic imaging apparatus according to claim 16 . Said means (IP) for calculating a panoramic image (200),
A virtual panoramic curve (400) representing a desired tomogram represented by the panoramic image (200) is generated in relation to the information of the position and orientation of the X-ray source (26) and the X-ray detector (16). Then, a desired point (P) on the virtual panoramic curve (400) corresponding to the pixel row (C) of the generated panoramic image (200) is obtained and viewed from the focus of the X- ray source (26). Means for generating a pixel column (C) of the panoramic image (200) by adding the pixel columns of the individual frames (300) onto which the point (P) is projected. Said means, wherein P ′) defines the projection direction of said point (P) in a particular individual frame (300);
including,
The dental panoramic imaging apparatus according to claim 17 .