Translation scanning tomography method, apparatus and readable storage medium

Abstract

A translation scanning tomography method, device and readable storage medium, wherein the translation scanning tomography method comprises: controlling a ball tube and a detector of a digital radiographic system to move synchronously at a preset speed, controlling the digital radiographic system to expose every preset time interval, acquiring two-dimensional images collected by the detector, determining position information of each two-dimensional image according to the preset speed and the preset time interval, and obtaining a reconstructed three-dimensional image according to a projection angle of pixels in the collected two-dimensional images and the position information. The translation scanning tomography method, device and readable storage medium can reduce the complexity of the motion structure of the DR system and the high-precision requirement of the motion feedback device, and reduce the cost.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of image processing, and particularly relate to a translational scanning tomography method, device and readable storage medium. BACKGROUND

[0002] Digital radiography (DR) is a medical device that converts X-ray information penetrating the human body into digital signals through an X-ray detector, and processes and displays X-ray images by a computer. The DR device can generally only obtain two-dimensional images.

[0003] In the prior art, a three-dimensional image is generally obtained based on tomographic imaging, which is a three-dimensional imaging technology based on DR. Wide-angle scanning is a mainstream scanning method for tomographic imaging, that is, projection data at different angles is obtained through a large-angle ball tube, and a three-dimensional image is then reconstructed. However, the prior art has high requirements for the complexity of the motion structure of the DR system and the feedback accuracy, resulting in high cost. SUMMARY

[0004] Embodiments of the present application provide a translational scanning tomography method, device and readable storage medium, which can solve the problems of complex motion structure, high feedback accuracy requirements and high cost.

[0005] In one aspect, the present application provides a translational scanning tomography method, comprising:

[0006] controlling a ball tube and a detector of a digital radiography system to move synchronously and translationally at a preset speed, and controlling the digital radiography system to expose every preset time interval;

[0007] obtaining two-dimensional images collected by the detector, and determining position information of each frame of the two-dimensional images according to the preset speed and the preset time interval;

[0008] obtaining a reconstructed three-dimensional image according to a projection angle of a pixel in the collected two-dimensional images and the position information.

[0009] In one aspect, the present application also provides a translational scanning tomography device, comprising:

[0010] a control module configured to control a ball tube and a detector of a digital radiography system to move synchronously and translationally at a preset speed, and control the digital radiography system to expose every preset time interval;

[0011] an acquisition module configured to obtain two-dimensional images collected by the detector;

[0012] The processing module is configured to determine position information of each frame of the two-dimensional image according to the preset speed and the preset time interval, and to obtain a reconstructed three-dimensional image according to a projection angle of a pixel in the acquired two-dimensional image and the position information.

[0013] The embodiment of the present application also provides a readable storage medium, which stores a computer program, and the computer program is used to implement the translation scanning tomography method of the robot when executed by a processor.

[0014] According to the embodiments of the present application, the ball tube and the detector of the digital radiographic imaging system are controlled to move synchronously according to the preset speed, the digital radiographic imaging system is controlled to expose every preset time interval, the two-dimensional image acquired by the detector is obtained, the position information of each frame of the two-dimensional image is determined according to the preset speed and the preset time interval, and the reconstructed three-dimensional image is obtained according to the projection angle of the pixel in the acquired two-dimensional image and the position information, so that the DR system does not need to have a complex motion structure and a high-precision feedback device, and the cost is low. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application.

[0016] Figure 1 An implementation flowchart of the translation scanning tomography method provided by the embodiment of the present application is shown in the figure.

[0017] Figure 2 A schematic diagram of two three-dimensional slice images at different depths obtained by the translation scanning tomography method provided by the embodiment of the present application is shown in the figure.

[0018] Figure 3 A structural schematic diagram of the translation scanning tomography device provided by the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0019] In order to make the objects, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0020] Reference Figure 1An embodiment of the present application provides a flowchart of a translation scanning tomography method. For the convenience of description, only parts related to the embodiments of the present application are shown. The execution subject of the method is a terminal device, such as a computer, etc. The terminal device is connected with a DR system, and is used for processing image data sent from the DR system. The DR system can include a ball tube, a detector, a high-voltage generator, etc. The detector can be a flat panel detector. The method can include the following steps.

[0021] S101, controlling the ball tube and the detector of the digital radiography system to move synchronously according to a preset speed, and controlling the digital radiography system to expose every preset time interval.

[0022] Controlling the ball tube and the detector of the DR system to move synchronously according to a preset speed, and controlling the high-voltage generator of the DR system to expose every preset time interval, i.e. to expose every time interval.

[0023] Obtaining the start point and the end point of the selected scanning imaging range of a user, and calculating a motion start point. The motion start point is based on the start point of the scanning imaging range plus a pre-set distance. The pre-set distance is not less than the acceleration stroke of the translation movement. Controlling the ball tube and the detector to move synchronously from the motion start point to the motion end point, and stopping the movement when the motion end point is reached.

[0024] When the movement of the ball tube and the detector reaches a preset motion speed, controlling the high-voltage generator to expose x-rays according to the preset time interval, i.e. to expose every time interval.

[0025] Further, before controlling the ball tube and the detector of the DR system to move synchronously according to a preset speed, the method further includes calibrating the geometric parameters and motion parameters of the DR system.

[0026] Specifically, calibrating the distance (SID, source to image receptor distance) between the detector and the focal point of the DR system, the vertical projection point of the focal point on the image imaging plane, and the preset speed of the synchronous translation movement of the ball tube and the detector.

[0027] Calibrating the SID of the DR system specifically includes correcting the error of the SID caused by the assembly of the DR system.

[0028] Placing a calibration object with a known length l horizontally above the detector surface at a distance d, exposing the calibration object to obtain an image, measuring the length l' of the calibration object in the image, and according to the geometric structure of the DR system, the formula l / l'=(SID-d) / SID can be obtained. Knowing l, l' and d, the accurate SID can be obtained.

[0029] Calibrating the vertical projection point of the focal point on the image imaging plane.

[0030] The calibration phantom is a three-dimensional object with a preset height, the upper surface and the lower surface are parallel, the upper surface and the lower surface are placed with high-density attenuation points, and the line connecting the center points of the upper surface and the lower surface is perpendicular to the upper surface and the lower surface. Place the calibration phantom at the approximate center position of the detector surface, expose and collect images, and according to the offset direction of the upper surface center relative to the lower surface center, move the calibration phantom in the opposite direction of the offset direction, expose and collect images again, move in the opposite direction of the offset direction again, and repeat the above steps until the upper surface center and the lower surface center overlap, and the center point coordinates (x0, y0) when overlapping are recorded as the vertical projection point of the focal point of the ray on the imaging plane.

[0031] The preset speed of the synchronous translation motion of the ball tube and the detector is:

[0032] A length-scaled calibration object is placed on the scanning plane, and the calibration object is translated and scanned, the scale interval corresponding to the center line between two frames of N frames is measured in the image, and the motion speed v is obtained by dividing the scale interval by the time interval of N frames. The relationship between the speed value and the displacement v(s) can be obtained by calculating at different displacements, and the intermediate value is determined according to interpolation. When the motion is uniform, v(s) is a fixed value.

[0033] Through the above calibration of the geometric parameters and motion parameters of the DR system, accurate parameters can be obtained without high-precision structure and assembly process.

[0034] S102, acquiring the two-dimensional image collected by the detector, and determining the position information of each frame of two-dimensional image according to the preset speed and the preset time interval;

[0035] When the ball tube and the detector start to move, a synchronization signal is sent to the detector to control the detector to collect two-dimensional images, until the ball tube and the detector stop moving, then stop collecting images. The motion starting point and the motion ending point can be set, and images can be collected in any range within the motion stroke between them. The tomographic imaging range of the three-dimensional image reconstructed according to the collected images is not limited to the imaging field of the detector, and the application range is wide, and the clinical value is great.

[0036] According to the preset speed and the preset time interval, the position information of each frame of two-dimensional image is calculated, and the exposure position of the i-th frame of two-dimensional image is Si=Si-1+v(Si-1)*△t.

[0037] Wherein, Si is the collection position of the i-th frame of two-dimensional image, Si-1 is the collection position of the i-1-th frame of two-dimensional image, v is the preset speed, and Δt is the preset time interval.

[0038] S103, obtaining the reconstructed three-dimensional image according to the projection angle of the pixel in the collected two-dimensional image and the position information.

[0039] The three-dimensional image is specifically a three-dimensional slice image.

[0040] The two-dimensional image collected by the receiving detector and the position information of each two-dimensional image are recombined to obtain a new projection image, the recombined projection image is filtered, and the filtered projection image is reconstructed to obtain a three-dimensional slice image.

[0041] According to the characteristics that the X-ray is a cone beam, the images obtained by the X-ray at the same projection angle are recombined to obtain a projection image, and the images obtained by the X-ray at different projection angles are recombined to obtain a plurality of projection images at different projection angles.

[0042] Specifically, the projection angle corresponding to each pixel in the two-dimensional image is calculated, the pixels at the same projection angle in each two-dimensional image are combined to form a projection image, all the projection images are filtered, and the filtered projection image is reconstructed into a three-dimensional slice image according to the position information and the SID of the DR system.

[0043] The projection angle corresponding to each pixel in the two-dimensional image is calculated according to the distance between the detector and the ray focus SID, the y-axis coordinate of each pixel point, and the y-axis coordinate of the vertical projection center point of the ray focus on the image plane. The specific calculation includes: calculating the projection angle according to the SID of the digital radiographic imaging system and the offset y-y0 of each pixel point on the y-axis relative to the vertical center point of the ray focus on the image imaging plane, wherein y0 is the y-axis coordinate of the center point coordinate, that is, the y-axis coordinate of the vertical projection point of the ray focus on the image imaging plane. The calculation formula is projection angle a:

[0044] a = atan((y-y0) / SID)

[0045] The pixels at the same projection angle in each two-dimensional image are separately taken as a row, wherein the same projection angle refers to the angle between the ray plane and the center axis (i.e. the line connecting the focus and the vertical center point);

[0046] Specifically, the pixels at the same projection angle in the current two-dimensional image are taken as the first row, the pixels at the same projection angle in the next two-dimensional image are taken as the second row, and so on, so that N rows of pixels can be extracted from N two-dimensional images to form a new projection image.

[0047] Further, the collected two-dimensional images have R rows, and there are N two-dimensional images in total, the first row of each image is recombined to form a projection image, and the projection image has N rows; the second row of each image is combined to form another projection image, and so on, so that the R rows of two-dimensional images are recombined to form R projection images.

[0048] Filter all the projection images, and reconstruct the filtered projection images into three-dimensional slice images according to the position information and the SID of the DR system, specifically including:

[0049] Sequentially perform ramp filtering and low-pass filtering on all the projection images to reduce noise, and obtain filtered images, and obtain three-dimensional slice images according to the position information, the SID and a preset reconstruction algorithm.

[0050]

[0051] Wherein, x' = SID / (SID-z)*(x-x0)+x0, y' = SID / (SID-z)*(y-y0-Si)+y0+Si.

[0052] V(x, y, z) represents a point on a three-dimensional image; Pi(x', y') represents a point in a projection image.

[0053] Wherein, i [0, R].

[0054] Referring to Figure 2 , Figure 2 A schematic diagram of two three-dimensional slice images at different depths obtained by the translation scanning tomography method provided by the embodiment of the application.

[0055] In the embodiment of the application, the ball tube and the detector of the digital radiographic imaging system are controlled to move synchronously and translationally at a preset speed, and the digital radiographic imaging system is controlled to expose every preset time interval, to acquire two-dimensional images collected by the detector, and to determine position information of each two-dimensional image according to the preset speed and the preset time interval, to obtain a reconstructed three-dimensional image according to a projection angle of a pixel in the collected two-dimensional image and the position information, and the DR system does not need to have a complex motion structure and a high-precision feedback device, and the cost is low.

[0056] Referring to Figure 3 , a structural schematic diagram of the translation scanning tomography device provided by an embodiment of the application. For ease of illustration, only parts related to the embodiments of the application are shown. The translation scanning tomography device can be built into the terminal device in the above embodiments, and can mainly include the following modules:

[0057] The control module 301 is configured to control the ball tube and the detector of the digital radiographic imaging system to move synchronously and translationally at a preset speed, and to control the digital radiographic imaging system to expose every preset time interval.

[0058] The acquisition module 302 is configured to acquire two-dimensional images collected by the detector.

[0059] The processing module 303 is configured to determine position information of each two-dimensional image according to a preset speed and a preset time interval, and to obtain a reconstructed three-dimensional image according to a projection angle and the position information of pixels in the acquired two-dimensional image.

[0060] Further, the processing module 303 is further configured to calculate the projection angle corresponding to each pixel in the two-dimensional image.

[0061] Pixels with the same projection angle in each two-dimensional image are composed into a projection image.

[0062] All the projection images are filtered, and the filtered projection images are reconstructed into three-dimensional slice images according to the position information and the distance between the detector and the focal point of the DR system.

[0063] The processing module 303 is further configured to calculate the projection angle according to the distance between the detector and the focal point of the digital radiography system and the offset of the pixel point relative to the vertical center point of the image imaging plane on the y-axis.

[0064] The processing module 303 is further configured to sequentially perform a ramp filter and a low-pass filter on all the projection images to obtain filtered images.

[0065] The filtered images are obtained according to the position information, the distance between the detector and the focal point, and a preset reconstruction algorithm to obtain the three-dimensional slice images.

[0066] Further, the apparatus further comprises a calibration module (not shown in the figure). Figure 3

[0067] The calibration module is configured to calibrate the geometric parameters and the motion parameters of the digital radiography system.

[0068] Specifically, the calibration module is configured to calibrate the distance between the detector and the focal point of the digital radiography system, the vertical projection point of the focal point on the image imaging plane, and the preset speed.

[0069] For details of the implementation of the functions of the modules in this embodiment, refer to the foregoing description of the translation scanning tomography method in the foregoing embodiments. Figures 1-3

[0070] ​​In the embodiment of the present application, the control module controls the ball tube and the detector of the digital radiographic imaging system to move synchronously according to a preset speed, controls the digital radiographic imaging system to expose every preset time interval, the acquisition module acquires the two-dimensional images collected by the detector, and the processing module determines the position information of each two-dimensional image according to the preset speed and the preset time interval, obtains the reconstructed three-dimensional image according to the projection angle of the pixels in the collected two-dimensional image and the position information, and the DR system does not need to have a complex motion structure and a high-precision feedback device, and the cost is low.

[0071] The embodiment of the present application also provides a computer readable storage medium, which can be arranged in the terminal device in the above-mentioned embodiments, and the computer readable storage medium can be a memory in the terminal device. The computer readable storage medium stores a computer program, and the program is executed by a processor to realize the above-mentioned Figure 1 The computer readable storage medium described in the embodiment can be a U disk, a mobile hard disk, a read-only memory (ROM), a RAM, a magnetic disk or an optical disk, and various storage program codes.

[0072] It should be noted that, for the above-mentioned method embodiments, in order to be simple and convenient, the above-mentioned method embodiments are all described as a series of action combinations, but those skilled in the art should know that the present application is not limited to the action sequence described, because according to the present application, some steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification all belong to preferred embodiments, and the actions and modules involved are not necessarily necessary for the present application.

[0073] In the above-mentioned embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0074] The above is the description of the translation scanning tomography method, device and readable storage medium provided by the present application. For those skilled in the art, according to the idea of the embodiment of the present application, the specific implementation and application range will be changed, and the content of the specification should not be understood as the limitation of the present application.

Claims

1. A method of translational scanning tomography, characterized in that, The method comprises the following steps: controlling the ball tube and the detector of the digital radiographic imaging system to move synchronously and translationally at a preset speed, and controlling the digital radiographic imaging system to expose every preset time interval; acquiring two-dimensional images collected by the detector, and determining position information of each two-dimensional image according to the preset speed and the preset time interval; calculating a projection angle corresponding to each pixel in the two-dimensional image; grouping pixels of the same projection angle in each two-dimensional image to form a projection image; performing filtering processing on all the projection images, and reconstructing the filtered projection images into three-dimensional slice images according to the position information and the distance between the detector and the ray focus of the digital radiographic imaging system.

2. The method of claim 1, wherein, The calculation of the projection angle corresponding to each pixel in the two-dimensional image comprises the following steps: obtaining the projection angle according to the distance between the detector and the ray focus of the digital radiographic imaging system and the offset of the pixel point of the digital radiographic imaging system relative to the vertical center point of the imaging plane of the ray focus on the y-axis.

3. The method of claim 2, wherein, The filtering processing on all the projection images and the reconstruction of the filtered projection images into three-dimensional slice images according to the position information and the distance between the detector and the ray focus of the digital radiographic imaging system comprise the following steps: performing ramp filtering and low-pass filtering on all the projection images in sequence to obtain filtered images; obtaining the three-dimensional slice images according to the position information, the distance between the detector and the ray focus, and a preset reconstruction algorithm.

4. The method of claim 1, wherein, Before the control of the ball tube and the detector of the digital radiographic imaging system to move synchronously and translationally at a preset speed, the method comprises the following steps: calibrating geometric parameters and motion parameters of the digital radiographic imaging system.

5. The method of claim 4, wherein, The calibration of the geometric parameters and the motion parameters of the digital radiographic imaging system comprises the following steps: calibrating the distance between the detector and the ray focus of the digital radiographic imaging system, the vertical projection point of the ray focus on the imaging plane, and the preset speed.

6. A translational scanning tomography apparatus, characterized by The method comprises the following steps: a control module, configured to control the ball tube and the detector of the digital radiographic imaging system to move synchronously and translationally at a preset speed, and control the digital radiographic imaging system to expose every preset time interval; an acquisition module, configured to acquire two-dimensional images collected by the detector; a processing module, configured to determine position information of each two-dimensional image according to the preset speed and the preset time interval, calculate a projection angle corresponding to each pixel in the two-dimensional image, group pixels of the same projection angle in each two-dimensional image to form a projection image, perform filtering processing on all the projection images, and reconstruct the filtered projection images into three-dimensional slice images according to the position information and the distance between the detector and the ray focus of the digital radiographic imaging system.

7. The apparatus of claim 6, wherein, The processing module is further configured to perform ramp filtering and low-pass filtering on all the projection images in sequence to obtain filtered images; obtain the three-dimensional slice images according to the position information, the distance between the detector and the ray focus, and a preset reconstruction algorithm.

8. A readable storage medium, having stored thereon a computer program, characterized in that, The computer program is for implementing the translational scan tomography method as claimed in any one of claims 1 to 5 when being executed by a processor.

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