RU2677830C1 - Generating dental panoramic images - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: group of inventions relates to medical equipment, specifically to means of generating digital panoramic dental images. Method for generating a digital dental panoramic image, comprises using several individual overlapping frames taken along a dental arch by a dental panoramic x-ray imaging apparatus, said apparatus including an x-ray source for generating an x-ray beam and having a focus, and an image detector having pixel columns, and said frames being taken by moving the x-ray source and the image detector around a patient's head, and calculating the panoramic image by summing information of the frames, wherein the panoramic image is generated by summing information of the frames with respect to information of location and orientation of the x-ray beam and the x-ray detector at times when taking the frames, forming a virtual panoramic curve taking into account the information of the location and the orientation of the x-ray beam and the image detector, which shows the desired tomographic layer, which will be shown through the panoramic image, determining the location of the desired point or points (P) taking into account information of the location and orientation of the x-ray beam and the image detector at times when taking the frames, and determining the location of the desired point or points (P) on the curve for the column (C) of the generated panoramic image, forming a column (C) of the panoramic image by summing up those columns of individual frames for which the point (P) is projected as observed from the focus of the radiation source, and said projection (P-> P') determines the direction of the projection point (P) in relation to a particular individual frame, determining the desired direction of observation (D) for at least one desired point (P) and calculating for a column in a separate frame a weighting factor which is based on the angle between the direction of observation (D) and the direction determined by a line extending from the focus of the radiation source to said point (P), and using a weighting factor in summing information from frames to give less weight to a column of a frame with a large angle between the direction of the vector, showing the desired direction of observation (D), and said direction determined by a line extending from the focus of the radiation source to the point (P). Method of generating and presenting digital dental panoramic images includes using several separate overlapping frames taken along the dental arch by means of an x-ray device for generating a dental panoramic image, said apparatus including an x-ray source for generating an x-ray beam and having a focus, and an image detector having pixel columns, and a display, and the frames are taken by moving the x-ray source and the image detector around the patient’s head, calculating the panoramic image by summing information from the frames, and presenting the panoramic image of the tomographic layer thus formed on the display, wherein at least two panoramic images observed from different directions are generated, and for each such direction of observation several images showing different tomographic layers are generated, for each such observation direction, one of said several images, showing the different tomographic layers, is chosen to represent said direction of observation, and said at least two panoramic images showing views from different directions are presented on the display simultaneously, sequentially, as a combination image or as a moving image. Methods are carried out by means of corresponding devices comprising an x-ray source having a focus, and an image detector having a plurality of pixel columns, wherein the x-ray source and the image detector are placed in the device at a distance from each other, drive means for moving the x-ray source and the image detector around the patient's head, a control system (CS), and a user interface (UI).EFFECT: inventions widens the capacity of generating dental panoramic images from frame data obtained with a single scan.18 cl, 7 dwg

Description

FIELD OF THE INVENTION

The invention, in General, relates to the formation of dental panoramic images and, more specifically, to the formation of digital dental panoramic images from multiple image frames obtained during scanning around the patient's head to form a dental panoramic image.

BACKGROUND OF THE INVENTION

The traditional operating principle of panoramic X-ray machines involves driving the x-ray source and the film cassette around the patient’s head, while the film is moved relative to the x-ray so that the dentition (dental arch) will be displayed as a flat image on the film.

This basic operation of the traditional formation of dental panoramic images involves creating a corresponding mutual movement between the x-ray source, the graphic information receiver and the patient. Although there are a number of other possibilities for creating such a movement, the most common way would be to attach the x-ray source and the graphic information receiver to the bracket at a distance from each other, and this bracket would then be moved in a certain way relative to the stationary patient. In this context, in order to obtain a sharp image of the desired layer in the object, that is, the dentition layer in the patient’s head, the speed of the film must be related in a certain way to the scanning speed of the x-ray along the desired layer to be captured. In accordance with this device, unnecessary structures in front and behind the desired layer in the patient’s head are blurred and become invisible.

In the traditional formation of a panoramic image, the thickness of the layer that will be photographed sharply is directly proportional to the distance to the instantaneous center of rotation of the bracket from the plane of the film and inversely proportional to the increase and width of the beam.

This basic equation for the formation of a panoramic image can be expressed as follows:

vI / vO = L1 / L0,

vO = ωr,

Where:

L0 is the distance from the focus of the x-ray tube F to the point of the object currently being displayed;

LI is the distance from the focus of the x-ray tube F to the plane of the x-ray film (or detector);

ω is the angular velocity of rotational motion around the instantaneous center of rotation;

r is the distance to the displayed point of the object from the instantaneous center of rotation; and

vI is the speed of the image point on the plane of the film (detector).

The speed vI, therefore, refers to the speed at which the film moves during scanning to form a panoramic image relative to the x-ray incident on the film. As for digital imaging, when the so-called Time Delayed Integration (TDI) technology is used for image formation, the pixel charge transfer rate through the detector is made to match the speed of the film. Thus, the image data read from the sensor will correspond to the panoramic image on the film in the sense that the blurring of the layers outside the desired layer is already performed when the scanning and charge transfer process is carried out so as to obey this image formation equation. In this context, with regard to the choice of the tomographic layer to be imaged, image processing after exposure is not required, and would even be impossible, since the data read from the sensor already represents the same layer that corresponds to speed v1.

The prior art for generating digital panoramic images also includes the so-called frame transfer technology (Frame Transfer, FT). When using FT or any other technology in which many individual overlapping frames are taken during scanning to form an image, when they want to view the same layer that could be obtained by following the traditional panoramic image formation equation presented above, the degree of overlapping frames at the construction of the layer, which will be viewed as sharp, must be made such that it matches the speed vI.

One advantage that frame-by-frame technology contributes to is that by changing the degree of overlap, you can to some extent change the tomographic layer after exposure, since the degree of overlap of frames used in image processing determines the layer that will be relatively enhanced, while others will blurred. The amount by which it is possible to change the layer depends on how and with what type of funds the data from the frames were obtained. As a rule, however, only minor changes in the location of the layer are possible.

However, although panoramic systems with frame-by-frame transfer of the prior art include the possibility of a slight change in the sharpness of the layer, the degree of overlap used in the construction of the image is based on some predetermined scheme. These schemes typically include the use of standard frame overlap, and the actual calculation of the panoramic image does not include any parameter that would relate to the actual image formation geometry in the image forming system at the exposure positions of the frames.

In addition, since the direction of observation of the anatomical structure is primarily dictated by the image formation geometry used to obtain data from the frame, that is, the geometry according to which the image forming means (X-ray source and image information receiver) move when the data from the frame is obtained, prior art systems remained with this direction of observation, since they lack the means to change the direction of observation from which I show Panoramic images or portions thereof.

Further, even though the frame-by-frame imaging technology allows the use of wider detector areas than is possible in practice using more traditional continuous scanning methods, there are criteria, such as those that relate to the need to be able to read a frame quickly enough during scanning for image formation, and also not to have big changes in relation to the increase in one frame, which also sets a number of practical restrictions on the width of the detectors, which These can be used in frame-by-frame formation of panoramic images of teeth of the prior art.

SUMMARY OF THE INVENTION

The main objective of the invention and preferred forms of its implementation is to provide a system whereby image data from frames obtained by a single scan to form a panoramic image can be used in connection with the knowledge of the true geometry of image formation used in the image formation procedure, in with respect to each exposure position so as to provide new opportunities for the formation of dental panoramic images from data from firewood after exposure. Additional objectives of the invention include the ability to not only generate more than one tomographic layer from image data from frames obtained by a single scan to form a panoramic image, but also to create and display images or image components of the dentition viewed from different directions.

These and other objectives of the invention, which will be discussed below, can be achieved by the forms of the invention, as defined in the attached claims. The essence of the invention is the implementation of panoramic scanning so that the information on the geometry of the image formation, which is the location and orientation of the detector and the focus of the x-ray tube and thus the x-ray beam, is known at their exposure positions, and this information is then used in calculating the dental panoramic image . Advantages that provide various forms of carrying out the invention include the possibility of forming a dental panoramic image from a single set of data from frames, as viewed from more than one direction. If it is possible to virtually change the viewing angle, those features of the anatomical structure that are not visible from a certain other viewing direction may become visible. Thus, for example, overexposure of the patient with x-rays can be avoided due to the need for image re-recording. In addition, the forms of the invention, discussed below, provide the possibility of using wider detectors than are commonly used in frame-by-frame formation of a dental panoramic image.

Brief Description of the Drawings

The present invention and some of the preferred forms of its implementation will be discussed below, with reference to the accompanying drawings.

In FIG. 1 shows an example of a panoramic imaging apparatus.

In FIG. 2 shows some of the main components of a system for implementing the embodiments of the invention discussed below.

In FIG. 3a shows a dental panoramic image, and FIG. 3b is an image of a single frame from which a dental panoramic image can be formed.

In FIG. 4 shows separate overlapping frames together with a line showing a vertical portion of the anatomical structure that is projected onto different places of the frames as the image detector moves to new exposure positions.

In FIG. 5 is a schematic drawing explaining the principle of a panoramic image forming process according to an embodiment of the invention.

In FIG. 6 shows the steps of a method in which the principles of the invention are applied.

In FIG. 7 is a schematic drawing illustrating a configuration of information processing / computing system hardware that may be used in implementing the invention.

DETAILED DESCRIPTION OF THE INVENTION

The forms of carrying out the invention discussed here, and their various features and advantageous details are explained in more detail with reference to non-limiting forms of carrying out the invention, which are illustrated in the accompanying drawings and are detailed in the following description. Descriptions of known components and processing techniques are omitted so as not to unnecessarily complicate the understanding of the embodiments of the invention provided herein. The examples used herein are intended simply to facilitate understanding of the ways in which the forms of the invention described herein can be practiced, and in addition to enable those skilled in the art to practice the forms of the invention described herein. Accordingly, these examples should not be construed as limiting the scope of the embodiments described herein.

It should also be understood that embodiments of the invention are given by way of example. For example, if the description refers somewhere to “one” or “some” form (s) of the invention, this does not necessarily imply that each such reference refers to one form (s) of the invention, or that a feature applicable to only one embodiment of the invention. Certain features of the various forms of the invention may be combined to offer other forms of the invention, even if this has not been explicitly disclosed in this context.

The embodiments described herein use information about the location and orientation of the X-ray beam and X-ray detector when taking overlapping frames along the dentition to form a dental panoramic image. For example, the forms of the invention discussed below allow the user to view certain points of interest of the dentition from an angular region, that is, from more than one viewing direction. Thus, the forms of the invention described herein may allow the user to consider certain features among the patient’s teeth on a panoramic panoramic radiograph, for example, those features that may not be visible on another panoramic panoramic radiograph formed using methods and devices of the prior art.

From the accompanying drawings, FIG. 1 is a design of an exemplary X-ray panoramic imaging apparatus. The device comprises a base 27 and a column-like rack portion 12 attached at its lower end to the base 27. The support bracket 13 (shown without its cover) is rotatably mounted on the upper end of the rack portion 12. Accordingly, at the outer end of the support bracket 13 is mounted rotatably mounted another intermediate support bracket 14, at the outer end of which is further mounted rotatably mounted the image forming bracket 15, or C-bracket, as it is often called. The C-bracket 15 supports imaging means, i.e., an X-ray source 26 and an image detector 16. In addition, the positioning support 25 is attached to a similar column of the rack portion 12 to assist in positioning the person whose image you want to receive. Instead of the column-like column portion 12, the rotating support bracket 13 can also be mounted on wall or ceiling structures.

The construction shown in FIG. 1, has been simplified for the sake of clarity. For example, means receiving the force, serving as a means of driving structures 13-15 of the bracket, are not shown in the drawing. Similarly, the stepper motors 1 for rotation of the structures 13-15 of the bracket shown in a simplified form.

The device shown in FIG. 1, and its control system (not shown in FIG. 1) is an example of a structure for moving the center of rotation of the C-arm 15, which carries imaging means to scan to form a panoramic image around the patient’s head using basically any desired trajectory center of rotation. The designs of the dental panoramic imaging device are different and in the simplest imaging device, only one fixed imaging geometry can be allowed.

The main components of the system for implementing the invention, as shown in FIG. 2 comprise a control system (CS) of an image forming apparatus that comprises or is in operative communication with motors 1 driving a bracket or brackets 13-15 of the apparatus and with the operating electronics of detector 16. The system comprises a storage device that among other things, it records image information from frames and information regarding the associated image formation geometry, processing means (Image Processor, IP) for creating a panoramic image, a screen (Screen, S) for displaying images and user interface (User Interface, UI).

In FIG. 3A shows a typical dental panoramic image 200. When a digital panoramic image 200 is created from image data from frames obtained during scanning to form a panoramic image, FIG. 3B can be considered showing one of hundreds or thousands of images 300 of partially overlapping frames that are captured during a scan. In FIG. 4 then shows the principle of how overlapping individual frames 310, 315, 320 obtained during scanning to form a panoramic image can be used to create a digital panoramic image 200. Line 210, which vertically overlaps frames 310, 315, 320, represents the location of the column pixels in each of the frames, which contains information from the image of the same thin vertical section of the displayed anatomical structure. The information from the image that these columns contain is used to create a column of pixels C of the final digital panoramic image 200 to be generated, which will be discussed in more detail below. Frames shot before frame 310 and after frame 320, which are not intersected by line 210 and therefore do not contain information regarding a specific area of the anatomical structure that line 210 shows, will not contribute to this specific column C of the generated panoramic image 200.

In FIG. 5 is a schematic drawing for explaining the principles of a panoramic image forming process according to the invention. The process uses what will be called the virtual panoramic curve 400 here, along with data on the location and orientation of the imaging tools during exposure in the coordinate system of this curve. In other words, and as will be discussed in more detail below, the process includes placing a virtual panoramic curve 400 representing the location and shape of the tomographic layer that will be formed in the coordinate system of the imaging geometry used when shooting frames.

In FIG. 5, a plurality of points (P1, P2, P3, P4) are shown on the virtual panoramic curve 400, each of which can be considered corresponding to the location of the area of the anatomical structure that will be depicted in the panoramic image. In other words, each point (P1, P2, etc.) represents the location of the vertical layer of the dentition, which must be depicted as a separate column of pixels in the generated digital panoramic image.

Furthermore, in FIG. 5 shows two exposure positions, i.e., the positions (E ′, E ″) of the X-ray source and the detector during exposure, and thus shows that part of the X-ray that penetrates the displayed anatomical structure and reaches the detector. When this imaging geometry is known, it will be possible to determine the location of the projection P of each point P on the detector at each of the exposure positions at which the projection P 'falls on the detector. These projection points P 'define the columns of pixels on the detector that should be used when constructing the panoramic image column C showing the given PN point of the anatomical structure, the projection of which P-> P' can be considered to determine the projection direction of point P related to a particular individual frame 300.

As can be seen in FIG. 5, in the first exposure position E ', the projection P'2 of the point P2, when viewed from the focus of the radiation source, falls on the detector (frame) in a place that is quite far from the center of the detector, while in the second position E' 'the projection P''2 falls mainly in the center of the detector. This option is a case that the prior art image creation process may skip when summing columns of overlapping frames by some standard predetermined procedure, while the forms of the invention described here allow you to select the columns that are used to create a panoramic image based on the actual knowledge of imaging geometry. In other words, instead of simply summing the information of the column of overlapping frames according to some standard summation protocol, that particular column of each of the image frames is determined where the projection of some specific point P1, P2, etc. lies, if you look from the instantaneous location of the x-ray focus beam during image capture, and these columns are used when calculating the C columns of the generated panoramic image.

Knowing the geometry of the imaging, that is, the location and orientation of the X-ray source and the X-ray detector during scanning for imaging, it is also possible, by changing the shape or orientation, or both of the panoramic curve 400, not only to calculate the various layers of the anatomical structure as those, but also create and display object layers viewed from different directions. This feature of the invention can be understood by assuming that the panoramic curve 400 shown in FIG. 5, could be rotated slightly counterclockwise around point P4. Given the positions of the image formation E 'and E' ', this would lead to the projection of P'2 and P''2 to the left shift on the detector (on the frame, if viewed from the side of the x-ray source) and, thus, the information of other columns of pixels could be selected for use in creating a panoramic image. These other columns would then show not only a different layer, but also a different viewing angle of the object, different from the angle according to FIG. 5.

In principle, you can use the virtual panoramic curve 400 of any shape and place it in any orientation in the coordinate system of the image-forming geometry. This makes it possible to create tomographic layers having shapes that are even very versatile in FIG. 1 could not create a simple mechanical displacement of the device bracket structure.

As another aspect, a separate local observation vector D can be defined for a number of points P1, P2, etc. In addition to what was discussed above, as shown in FIG. 5, the vector D is included in the drawing to indicate the desired local direction of observation of point P2. Such vectors D can be used to determine weights for the pixel values of the column of frames showing specific points P1, P2, etc. anatomical structure. For example, as can be seen in FIG. 5, the angle between the vector D and the projection direction, determined by the line starting from the focus of the radiation source and ending at the projected point P ', is slightly larger in the second exposure position E' 'than in the first exposure position E' shown in FIG. 5. When this embodiment is applied, when constructing the image, the pixel values of the column of the projected point P'2 of the second exposure will be given relatively less weight than the values of the projected point P'2 of the first exposure. When this principle is applied to the projection P 'of the point P, that is, when more weight is given to the pixel values of a certain projection direction than others, the features of the anatomical structure, as visible from the preferred direction, will be highlighted.

The flowchart shown in FIG. 6 illustrates one preferred method for implementing the principles of the invention. In a first step 500 of the method shown in FIG. 6, frames and corresponding exposure positions of the frames are read during scanning to form a panoramic image that has been performed. Then, at step 510, a virtual panoramic curve is obtained, which they want to use when building the image; this curve is then divided in step 520 into a plurality of points P, or, in other words, a plurality of points P is selected from the curve, preferably equidistant, to determine the points of the anatomical structure that should correspond to the columns C of the generated panoramic image. A separate observation direction D for points P can be determined at step 530.

In practice, in view of the imaging geometry that is used for scanning to form a panoramic image, it would be preferable to know about the virtual panoramic curve or curves 400 planned for use in imaging so that the imaging geometry appropriately allows the formation of such a desired layer or layers.

Having now all the data at your disposal, you can begin the formation of columns C of the panoramic image 200 that you want to create (step 540). First, point P, which corresponds to column C of the panoramic image, and the local observation direction D associated with it, if this was determined for point P, is found at step 550. Then, since the panoramic curve 400 and the corresponding locations and orientations during exposure of each frame and source radiation are known, processing can be performed for each of the frames (step 560), while at first at step 570 the point P is projected onto the frame along a line that starts from the focus of the radiation source. In practice, for most frames there will be no projected point P ', since the line emanating from the focus of the x-ray source and passing point P on the panoramic curve does not intersect most frames, but for the few remaining frames, the projected point P' on the frame will determine the column pixels of that particular frame to be used when creating column C of the panoramic image shown by the point P in question (steps 580 and 610).

If the local direction of observation D for a given point P was determined, the process further includes determining at step 590 the angle between the local direction of observation D and the line coming from the focus of the x-ray source and crossing the point P. This angle can be used at step 600 as weighting factor in order to give less weight when constructing the image (step 610) to those frames (i.e., the pixel values of the projected point P 'of the frame) for which the projection direction of the point P (or, in other words, in wearing Fig. 5, the vector from P to P ') deviates more from the desired local direction of observation D. After completion of this process (step 620), the pixel values of each column C of the final panoramic image are normalized by dividing the values of the given column by the total sum of the weight coefficients of this column .

The above procedure can be represented in more general terms, which includes the use of several separate overlapping frames 300, taken along the dentition by an X-ray panoramic imaging device; said device comprising an x-ray source for generating an x-ray having a focus and an image detector having columns of pixels. Frames 300 are captured when the X-ray source and image detector are moved around the patient’s head, and a panoramic image 200 is formed by summing the information from the frames 300, taking into account the location and orientation of the X-ray and the X-ray detector at the time the frames were taken. Summing up the information then may include determining the location of the desired point or points P, taking into account information about the location and orientation of the X-ray beam and the X-ray detector at the time of shooting frames, while summing information from frames 200 then includes summing the column or columns C of the panoramic image 200 with respect to the point or points P. On the other hand, at least two panoramic images 200 can be formed when viewed from different directions, and at least two images Niya, representing the views from different directions, and then be played back on the display simultaneously, sequentially, as the Raman image or as a moving image.

An embodiment of the invention may also include generating a virtual panoramic curve 400, which shows the tomographic layer to be displayed by the panoramic image 200, placing this curve 400 and information about the location and orientation of the x-ray beam and the x-ray detector in the same coordinate system, and the formation of a panoramic image 200, which shows the tomographic layer, according to the location of the curve 400 in this coordinate system.

Another embodiment of the invention may include forming, taking into account the location and orientation of the X-ray beam and X-ray detector, a virtual panoramic curve 400 showing the desired tomographic layer to be shown by the panoramic image 200, and for the column C of the generated panoramic image 200 to determine the desired point P on curve 400, as well as the formation of column C of the panoramic image 200 by summing those columns of individual frames 300 for which point P is projected as observed from the focus of the radiation source, and this projection P -> P 'determines the direction of projection of point P with respect to a particular individual frame 300.

With regard to the weighting coefficient, processing associated with it can be presented to include determining the desired viewing direction D for at least one point P, the weighting factor being calculated for the column on a separate frame 300 based on the angle between the viewing direction D and the direction determined by the line, passing from the focus of the radiation source to said point P; the weighting factor is then used when summing information from frames 300 so as to give less weight to the column of the frame with a large angle between the direction of the vector D, showing the desired direction of observation, and the direction determined by the line passing from the focus of the radiation source to point P.

The virtual panoramic curve used in the above-described embodiment of the invention can be represented by a tool that allows you to change the tomographic layer in a controlled manner, taking into account the imaging geometry used to obtain data from frames, and which can also be used to change the direction from which the anatomical structure is viewed or part thereof. By changing the shape or orientation of the virtual panoramic curve, or both, and using the local observation direction vector discussed above, different images of the dentition can be created on the basis of the same set of data from the original x-ray image frames obtained in one scan to form panoramic image.

The virtual panoramic curve 400 for use in forming a panoramic image can be determined in many different ways. One preferred method is to first generate a curve that executes the basic panorama equation discussed above with respect to the movements of the imaging means. When the movements of the image forming means in a panoramic image forming apparatus of a given type are often fixed, or the same several standard movements are usually used, a panoramic curve 400 corresponding to a specific image forming procedure can be created and saved for later use. Additionally, the previously used or stored virtual panoramic curve, or the virtual panoramic curve that has just been used, can be modified, for example, by a method that includes a linear transformation of all points P and the associated viewing directions. Linear transformation may include rotational and translational parts. The change may also include the use of a nonlinear imaging function, such as a two-dimensional spline surface, which can be used to deform the panoramic curve.

Embodiments of the invention include, as noted, new methods not only for creating dental panoramic images as such, but also for displaying them on a display. For example, when information about the location and orientation of the X-ray beam and the X-ray detector during shooting is available, two or more panoramic images that are viewed from different directions can be formed by summing the information from the frames in different ways, taking into account the location information and the orientation of the x-ray beam and the x-ray detector, which in turn allows you to display images as viewed from different directions on the display, For example, simultaneously, sequentially, or as a Raman image as a moving image.

For example, the first and second virtual panoramic curves can be formed taking into account information about the location and orientation of the x-ray beam and the x-ray detector; both curves represent the desired layer to be displayed by means of the panoramic image, the second curve is formed from the first curve by changing the orientation of the first curve, and the two panoramic images will then be calculated by summing the information from the frames obtained in the process of forming the panoramic image in relation to these different curves . Of course, more than two curves can be used, and, for example, the illusion of rotation of the dentition can be created when consistently showing panoramic images with a change in the direction of observation. In other words, this type of embodiment of the invention may include displaying the images sequentially according to the order of their viewing direction so as to give the impression of a rotation of the dentition on the display.

Another embodiment of the invention may include the formation of several panoramic images as viewed from different directions, the formation for each such direction of observation of several images showing different sharp layers, and then with respect to each such direction of observation one of these several images showing different sharp layers, may be selected to represent the aforementioned direction of observation, after which images selected in this way can be represented s on the display - with reference to the above, for example, simultaneously, sequentially, as a combination image or as a moving image.

The use of a weight coefficient, as discussed above, can improve the effect of different viewing angles by emphasizing the columns that have the main path of x-ray radiation more appropriate to the viewing angle of the panoramic curve at a given point P.

The use of weights also contributes to the possibility of using wider surfaces of the detector than are commonly used in applications of single-frame panorama of teeth. When summing data from frames of the prior art is based on some standard overlap procedure, it is very likely that the columns that are summed together will not represent the same section of the anatomical structure that moves farther away from the center of the detector. This is due to the fact that the summation protocol does not know the exact changes in the complete image formation geometry during the exposure process, that is, there are changes in the relative positions and orientations of the image forming means and the layer that they want to form. By using the principles discussed here, the blurring of the panoramic image due to the addition of information to the columns C of the panoramic image 200 representing the changing places of the anatomical structure can be avoided. A weighting factor can also be used to compensate for changing magnification.

With regard to the embodiments of the invention, one possibility to create the illusion of rotation of the displayed anatomical structure is to use only one virtual panoramic curve, and yet form various panoramic images on its basis by systematically changing the orientation of the vectors of the local observation direction D of the points P discussed above. In general, it is clear that the scope of the invention from the point of view of displaying the observed anatomical structure based on data from frames obtained during one scan to form a panoramic image includes any combination of modifying the virtual panoramic curve 400 and the orientation of the local direction vectors D of points P, including changing only the selected the number of vectors D so as to display different layers of the anatomical structure and from different viewing angles, or just any of them.

The embodiments described herein allow the use of a dental panoramic image forming apparatus that comprises an x-ray source having a focus, and an image detector having a plurality of pixel columns, the x-ray source and image detector are located in the device on first distance from each other; drive means for moving the x-ray source and detector around the patient's head; a control system including means for controlling the device so as to shoot several separate overlapping frames along the dentition. The detector can be implemented with a width equal to or greater than the second distance, and the control system is configured to control the device so as to shoot frames whose width is equal to the second distance, and the second distance is approximately 2-10% of said first distance. In an embodiment of the invention, the distance between the x-ray source and the image detector may preferably be approximately 500-550 mm.

As already mentioned, the forms of implementation of the invention discussed here can also allow you to display anatomical structures that otherwise could not be made visible, at least without exposing the patient to an additional process of panoramic irradiation. When it is possible to change the viewing angle, those details of the displayed anatomical structure that otherwise would not be visible may become visible. For example, filling a tooth may prevent the visibility of the tooth from reaching the other side of the dentition, but changing the direction of observation may ultimately make such a tooth visible.

In FIG. 7 is a diagram that illustrates a hardware set of an information processing / computing system by which embodiments of the invention can be implemented. The system 1000 shown in FIG. 7 contains at least one processor or central processing unit (Central Processing Unit) 1010. The central processing units 1010 are connected via a system bus 1012 to various devices, such as random access memory (RAM) 1014, read-only memory (Read -Only Memory, ROM) 1016 and adapter 1018 I / O (Input / Output, I / O). An I / O adapter 1018 can connect to peripheral devices such as disk storage devices 1011 and magnetic tape storage devices 1013 or other program storage devices that are readable by system 1000. System 1000 can read commands of the invention from program storage devices and follow these commands to execute the methods of the embodiments described herein. In addition, the system includes a user interface adapter 1019 that connects a keyboard 1015, a mouse 1017, a speaker 1024, a microphone 1022, and / or other user interface devices to the bus 1012, such as a touch screen (not shown), to collect input from user. Additionally, the communication adapter 1020 connects the bus 1012 to the data processing network 1025, and the display adapter 1021 connects the bus 1012 to the display 1023, which can be implemented as a data output device, such as, for example, a monitor, printer, or transmitter.

Thus, another embodiment of the invention comprises a dental panoramic imaging device that comprises an x-ray source having a focus and an image detector that has a plurality of pixel columns; moreover, the x-ray source and said image detector are placed in the device at a distance from each other; drive means for moving the x-ray source and detector around the patient's head; a control system comprising means for controlling the device so as to take several separate overlapping frames along the dentition, as well as a user interface for transmitting control commands to said control system; the control system has recorded information about the location and orientation of the x-ray source and the x-ray detector during the shooting of frames, and includes means for calculating the panoramic image by summing the information from the frames taking into account the mentioned information so as to form panoramic images observed from at least two different directions.

A dental panoramic imaging device with design features of the above paragraph can also be used as containing a control system and / or image processing or other features related to obtaining and constructing images according to any of the forms of the invention described here.

The preceding description of specific forms of carrying out the invention so fully reveals the general nature of the forms of carrying out the invention in this document, that other specialists can, using existing knowledge, easily modify and / or adapt to various applications these specific forms of carrying out the invention without departing from the general idea, and therefore such devices and modifications are intended to be understood as equivalent to the disclosed embodiments. It should be understood that the phraseology or terminology used here is intended to describe and not limit. Therefore, although forms of carrying out the invention have been described in terms of preferred forms of implementation, those skilled in the art will understand that the forms of carrying out the invention may be practiced with changes within the spirit and scope of the appended claims.

Claims (58)

1. The method of forming a digital dental panoramic image, including: - the use of several separate overlapping frames (300), taken along the dentition by means of an x-ray device for forming a dental panoramic image, said device comprising an x-ray source for generating an x-ray having a focus, and an image detector having columns of pixels, and shooting said frames (300) is carried out by moving the x-ray source and the image detector around the patient’s head; and - calculation of a panoramic image (200) by summing information from frames (300), moreover, a panoramic image (200) is formed by summing information from frames (300), taking into account information about the location and orientation of the x-ray beam and the image detector at the time of shooting frames, - the formation of a virtual panoramic curve (400), taking into account the above-mentioned information about the location and orientation of the x-ray beam and the image detector, which shows the desired tomographic layer, which will be displayed by means of a panoramic image (200), - determining the location of the desired point or points (P), taking into account the mentioned information about the location and orientation of the x-ray beam and the image detector at the time of shooting frames, and determining the location of the desired point or points (P) on said curve (400) for the column (C) of the generated panoramic image (200), - the formation of the column (C) of the panoramic image (200) by summing those columns of individual frames (300) for which the point (P) is projected as observed from the focus of the radiation source, and this projection (P-> P ') determines the direction of the projection of the point ( P) in relation to a particular individual frame (300), - determining the desired viewing direction (D) for at least one desired point (P), and calculating for the column on a separate frame (300) a weight coefficient that is based on the angle between the viewing direction (D) and the direction determined by the line passing from the focus of the radiation source to said point (P), and - using said weighting factor when summing information from frames (300) in order to give less weight to a column of a frame with a large angle between the direction of the vector showing the desired direction of observation (D) and said direction, determined by a line passing from the focus of the radiation source to said point (P). 2. The method according to p. 1, in which - said virtual panoramic curve (400) and said information about the location and orientation of the X-ray beam and the image detector are placed in the same coordinate system, and - form a panoramic image (200), which shows the tomographic layer according to the location of said virtual panoramic curve 400 in said coordinate system. 3. The method according to claim 2, in which the pixel values of the columns (C) of the final panoramic image (200) are normalized by dividing the pixel values of the specified column (C) by the total sum of the weight coefficients of this column. 4. The method of formation and presentation of digital dental panoramic images, including: - the use of several separate overlapping frames (300), taken along the dentition by means of an x-ray device for forming a dental panoramic image, said device comprising - an x-ray source for forming an x-ray beam having a focus, an image detector having pixel columns, and - a display functionally associated with said device, and shooting said frames (300) is carried out by moving the x-ray source and image detector around the patient’s head; - calculation of a panoramic image (200) by summing information from frames (300); and - a representation of the panoramic image (200) of the tomographic layer thus formed on the display, and form at least two panoramic images (200), observed from different directions, and - for each such direction of observation form several images showing different tomographic layers, - for each such direction of observation, one of said several images showing different tomographic layers is selected to represent said direction of observation, and said at least two panoramic images (200) showing views from different directions are displayed simultaneously, sequentially, as a combination image or as a moving image. 5. The method of claim 4, wherein said generating at least two panoramic images (200) comprises summing said information from frames (300) by at least two different methods, taking into account information about the location and orientation of the x-ray and image detector in moments of shooting frames (300). 6. The method according to p. 4 or 5, in which at least two panoramic images (200) are presented on the display sequentially according to the order of directions of their observation so as to create the impression of rotation of the dentition on the display. 7. The method according to claim 5, in which the location of the desired point or points (P) is determined taking into account the mentioned information about the location and orientation of the x-ray beam and the image detector at the time of shooting frames, and said summation of information from frames (300) includes summing the column or columns (C) of the panoramic image (200) with respect to said desired point or points (P). 8. The method according to p. 4 or 5, in which - form a virtual panoramic curve (400), which shows the tomographic layer that will be shown by means of a panoramic image (200), and this virtual panoramic curve (400) and the above-mentioned information about the location and orientation of the x-ray beam and the image detector are placed in the same coordinate system, and - said at least two panoramic images (200), observed from different directions, are formed by summing information from frames (300) taking into account the said virtual panoramic curve (400) so that the virtual panoramic curve (400) is placed in at least the first and second orientations in said coordinate system so that with respect to each of the orientations - for column (C) of the generated panoramic image (200), a point (P) is determined on said virtual panoramic curve (400), and - form the column (C) of the panoramic image (200) by summing those columns of individual frames (300) for which the point (P) is projected as observed from the focus of the radiation source, and this projection (P-> P ') determines the direction of the projection of the point ( P) in relation to a particular individual frame (300). 9. A device for forming a dental panoramic image containing - an x-ray source (26) having a focus and an image detector (16) having a plurality of columns of pixels, the x-ray source (26) and an image detector (16) being placed in the device at a distance from each other, - drive means (1) for moving the x-ray source (26) and image detector (16) around the patient’s head, - a control system (CS) comprising means for controlling a dental panoramic imaging device so as to shoot several separate overlapping frames (300) along the dentition, and a user interface (UI) for sending control commands to said control system, wherein - the control system (CS) has information about the location and orientation of the x-ray source (26) and the image detector (16) at the moments of shooting frames (300) and includes means (IP) for calculating the panoramic image (200) by summing information from the frames ( 300) taking into account said location and orientation information, to form panoramic images (200) observed from at least two different directions, and means for presenting said panoramic images (200) sequentially according to pores the core of the directions of their observation, so that the impression of a rotating dentition is created, and - the user interface (UI) comprises means for delivering at least one control command regarding the display of said panoramic images (200), observed from at least two different directions, so as to give the impression of a rotating dentition. 10. The device according to claim 9, wherein said control system (CS) comprises means for displaying said panoramic images (200) representing views from different directions, simultaneously, sequentially, as a combination image or as a moving image. 11. The device according to claim 9 or 10, wherein said control system (CS) comprises means (IP) for generating said panoramic images (200) by summing information from frames (300) by at least two different methods taking into account information about the location and orientation of the x-ray source (26) and the image detector (16) at the time of the shots (300). 12. The device according to claim 9 or 10, wherein said means (IP) for calculating panoramic images (200) comprises means for summing information from frames (300) taking into account information about the location and orientation of the x-ray beam and the image detector at the time of shooting frames . 13. The device according to p. 12, in which said means (IP) for calculating panoramic images (200) comprises means for generating a virtual panoramic curve (400), which shows a tomographic layer that will be shown by means of a panoramic image (200), for placement this virtual panoramic curve (400) and the aforementioned information about the location and orientation of the x-ray beam and the image detector in the same coordinate system, and to form a panoramic image (200), which shows tomographic sky layer according to a virtual location panoramic curve (400) in said coordinate system. 14. The device according to claim 13, wherein said means (IP) for computing panoramic images (200) comprises means for generating a virtual panoramic curve (400) taking into account said information about the location and orientation of the x-ray and image detector (16), which shows the desired tomographic layer, which will be shown by means of a panoramic image (200), for determining for column (C) the generated panoramic image (200) of the desired point (P) on said virtual panoramic curve (400), and for column (C) of the panoramic image (200) by summing those columns of individual frames (300) for which the point (P) is projected as observed from the focus of the radiation source, and this projection (P-> P ') determines the direction of the projection of the point (P ) with respect to a particular single frame (300). 15. The device for forming a dental panoramic image containing an x-ray source (26) having a focus and an image detector (16) having a plurality of pixel columns, said x-ray source (26) and said image detector (16) being placed at a first distance from each other in the device, - drive means (1) for moving the x-ray source (26) and image detector (16) around the patient’s head, - a control system (CS) comprising means for controlling the device so as to shoot several separate overlapping frames (300) along the dentition, wherein - the control system (CS) has information about the location and orientation of the x-ray source (26) and the image detector (16) at the moments of shooting frames (300) and includes means (IP) for calculating the panoramic image (200) by summing information from the frames ( 300) taking into account the mentioned information about the location and orientation, - said image detector (16) is implemented as equal in width to the second distance or greater than the width of the second distance, and - the control system is configured to control the device so as to shoot frames (300) whose width is equal to the second distance, the second distance being approximately 2-10% of the said first distance. 16. The device of claim 15, wherein said first distance is approximately 500-550 mm. 17. The device according to claim 16, wherein said means (IP) for computing panoramic images (200) comprises means for generating a virtual panoramic curve (400) that shows a tomographic layer to be shown by means of the panoramic image (200) for placement of this virtual panoramic curve (400) and the aforementioned information about the location and orientation of the x-ray beam and the image detector (16) in the same coordinate system, and for forming a panoramic image (200), which shows the tomograph the layer according to the location of the virtual panoramic curve (400) in said coordinate system. 18. The device according to claim 17, wherein said means (IP) for computing a panoramic image comprises means for generating a virtual panoramic curve (400) taking into account said information about the location and orientation of the x-ray beam and the image detector, which shows the desired tomographic layer, which will be shown by means of a panoramic image (200), for determining for column (C) the generated panoramic image (200) of the desired point (P) on said virtual panoramic curve (400), and for column (C) of the panoramic image (200) by summing those columns of individual frames (300) for which the point (P) is projected as observed from the focus of the radiation source, and this projection (P-> P ') determines the direction of the projection of the point (P ) with respect to a particular single frame (300).

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