X-ray flat panel detector timing synchronization and correction method and system

Abstract

The application discloses a kind of X-ray flat panel detector timing synchronization and correction method and system, image is acquired by flat panel detector;By timing control module, the main synchronization pulse is sent to the synchronization interface of flat panel detector on one hand, the working frequency of flat panel detector is controlled;On the other hand, the exposure window pulse returned by flat panel detector is frequency-division;After frequency-division, the secondary synchronization pulse is given to high voltage generator interface to control X-ray beam exposure;Image property is marked according to the pulse controlled by timing control module and the setting of frequency-division in the image acquired by flat panel detector in the above step 1;According to the strategy set, dark-field image multi-frame average or recursive average is carried out, and real-time offset correction data is generated.The offset correction data of the application is updated in real time, and does not need to be generated in advance, which greatly simplifies the generation mode of other correction files, solves the contradiction between the real-time application and the image quality of the equipment, and also provides a solution for variable frequency acquisition.

Description

Technical Field

[0001] This invention relates to the field of X-ray detector technology, and in particular to a method and system for timing synchronization and correction of an X-ray flat panel detector. Background Technology

[0002] X-ray examination is the most representative medical imaging method. X-ray imaging technology based on X-rays and flat panel detectors is widely used in DR (radiotherapy), RF (fluoroscopy), and CathLab (interventional) equipment. After acquisition, images from X-ray flat panel detectors require offset correction, gain correction, and bad pixel / bad line correction. To perform these corrections, correction data (maps) need to be generated in advance. Because the offset correction data is related to multiple factors such as detector temperature and mode, the dark field data needs to be refreshed as frequently as possible to generate offset correction data; otherwise, image quality will be affected, even significantly degraded. In RF (fluoroscopy) and CathLab (interventional) applications, the real-time performance requirements of the equipment are very high. In the current system operating mode, the equipment cannot refresh the dark field data during use. Here, a contradiction arises between the real-time requirements of clinical applications and the guarantee of image quality.

[0003] Extensive research revealed that Chinese patent document CN110161555A, for example, specifically discloses an X-ray detector calibration method, apparatus, system, and storage medium. The method includes: acquiring at least one frame of dark-field images to form a dark-field image set; generating a dark-field calibration template based on the dark-field image set, and performing dark-field calibration on the detector based on the dark-field calibration template; setting at least one X-ray dose point and acquiring a bright-field image set corresponding to the X-ray dose point; generating a bright-field calibration template based on the bright-field image set, and performing bright-field calibration on the detector based on the bright-field calibration template and the dark-field calibration template. By controlling different X-ray dose points and exposures, the detector is controlled to acquire a set of dark-field image sets and multiple sets of bright-field image sets with different X-ray dose points. A corresponding calibration template is generated based on the acquired image sets, and finally, the detector is automatically calibrated using the aforementioned calibration template, thus improving the efficiency of X-ray detector calibration.

[0004] like Figure 2 As shown, the current method for generating correction files (offset correction data, gain correction data, and bad pixel / bad line correction data) is to acquire image data multiple times for different detector operating modes and generate the corresponding data, which is a very time-consuming process.

[0005] In view of the above-mentioned shortcomings, the designer actively researched and innovated in order to create a timing synchronization and correction method and system for X-ray flat panel detectors, making it more valuable for industrial applications. Summary of the Invention

[0006] To address the aforementioned technical problems, the purpose of this invention is to provide a method for timing synchronization and correction of an X-ray flat panel detector.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] One of the objectives of this invention is:

[0009] A method for timing synchronization and correction of an X-ray flat panel detector.

[0010] The steps are as follows:

[0011] Step 1: Acquire images using a flat panel detector;

[0012] Step 2: Through the timing control module, on the one hand, a main synchronization pulse is sent to the synchronization interface of the flat panel detector to control the operating frequency of the flat panel detector; on the other hand, the exposure window pulse returned by the flat panel detector is divided into frequencies; the frequency-divided secondary synchronization pulse is sent to the high voltage generator interface to control the X-ray beam exposure.

[0013] Step 3: The image acquired by the flat panel detector in Step 1 above is marked with attributes according to the pulse and frequency division settings controlled by the timing control module.

[0014] Step 4: Perform multi-frame averaging or recursive averaging of the dark field image according to the set strategy to generate real-time offset correction data.

[0015] Step 5: If in calibration mode, set the flat panel detector mode to acquire X-ray images and dark field images at the same time, and generate corresponding gain correction data and bad pixel / bad line correction data.

[0016] Step 6: In working mode, since the calibration files are already available, the calibration of each frame of the image can be completed.

[0017] As a further improvement of the present invention, the image acquisition in step 1 includes the following steps in sequence:

[0018] Step 11: Acquire the image;

[0019] Step 12: Determine whether the original image obtained above is an X-ray image;

[0020] Step 121: If the acquired original image is an X-ray image, request image correction;

[0021] Step 122: If the acquired original image is a dark field image, regenerate the offset correction data and request image correction using the updated offset correction data;

[0022] Step 13: In step 121 or step 122 above, simultaneously request image correction using gain correction data and bad pixel / bad line correction data;

[0023] Step 14: Obtain a clean image after the above image correction.

[0024] As a further improvement of the present invention, in step 2, the exposure window pulse returned by the flat panel detector is divided by 1 / 2, 1 / 3, 1 / 4... 1 / N.

[0025] As a further improvement of the present invention, in step 3, the image is an X-ray image or a dark field image.

[0026] As a further improvement of the present invention, in step 4, the above-mentioned dark field image selection strategy uses the four dark field images closest to the X-ray image to generate offset correction data.

[0027] As a further improvement of the present invention, the weight configuration scheme for each frame of dark field image described above adopts an average weight.

[0028] As a further improvement of the present invention, in step 5, when setting the corresponding flat panel detector mode in the working acquisition state, the corresponding gain correction data and bad pixel / bad line correction data are loaded.

[0029] As a further improvement of the present invention, in step 6, the above-mentioned correction file includes offset correction data, gain correction data, and bad pixel / bad line correction data.

[0030] The second objective of this invention is:

[0031] An X-ray flat panel detector timing synchronization and correction system, which performs the timing synchronization and correction system as described in any one of claims 1 to 8.

[0032] By means of the above-described solution, the present invention has at least the following advantages:

[0033] This invention provides a novel method for timing synchronization and correction of X-ray flat panel detectors. Offset correction data is updated in real time and does not need to be generated in advance, which greatly simplifies the generation of other correction files (gain correction data and bad pixel / bad line correction data), resolves the contradiction between the real-time performance of the application and the image quality of the device, and also provides a solution for frequency conversion (i.e., changing the acquisition frame frequency in real time) acquisition.

[0034] This invention can update offset correction data in real time, solving the problem of previously requiring periodic (every 10-30 minutes) offset correction data refresh.

[0035] This invention can update offset correction data in real time. In particular, by using an X-ray image followed immediately by a dark field image to generate offset correction data, it can greatly solve the problem of lag in dynamic applications of X-ray flat panel detectors.

[0036] This invention can generate the corresponding working mode calibration file by performing an image acquisition once in calibration mode, making the detector calibration process simple and efficient.

[0037] This invention enables real-time frame rate switching without stopping data acquisition.

[0038] This invention can reduce the effective image output frequency of a flat panel detector.

[0039] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the structure of a timing synchronization and correction method for an X-ray flat panel detector according to the present invention;

[0042] Figure 2 This is the traditional workflow of acquiring images using a flat panel detector;

[0043] Figure 3 This is the process of acquiring images through a flat panel detector in the working mode of this invention;

[0044] Figure 4 It is traditional timing control;

[0045] Figure 5 This is the timing control of the present invention;

[0046] Figure 6 This is an example of a frequency-division image in this invention;

[0047] Figure 7 This is an example of a three-frequency image in this invention;

[0048] Figure 8 This is an example of the offset correction data generation strategy in this invention;

[0049] Figure 9 This is an example of dynamically switching the system output frequency in this invention. Detailed Implementation

[0050] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0051] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0052] Example

[0053] like Figures 1-9 As shown,

[0054] One of the objectives of this invention is:

[0055] like Figure 1 As shown,

[0056] A method for timing synchronization and correction of an X-ray flat panel detector.

[0057] The steps are as follows:

[0058] Step 1: Acquire images using a flat panel detector;

[0059] Step 2: Through the timing control module, on the one hand, a main synchronization pulse is sent to the synchronization interface of the flat panel detector to control the operating frequency of the flat panel detector; on the other hand, the exposure window pulse returned by the flat panel detector is divided into frequencies; the frequency-divided secondary synchronization pulse is sent to the high voltage generator interface to control the X-ray beam exposure.

[0060] Step 3: The image acquired by the flat panel detector in Step 1 above is marked with attributes according to the pulse and frequency division settings controlled by the timing control module.

[0061] Step 4: Perform multi-frame averaging or recursive averaging of the dark field image according to the set strategy to generate real-time offset correction data.

[0062] Step 5: If in calibration mode, set the flat panel detector mode to acquire X-ray images and dark field images at the same time, and generate corresponding gain correction data and bad pixel / bad line correction data.

[0063] Step 6: In working mode, since the calibration files are already available, the calibration of each frame of the image can be completed.

[0064] Preferably, the image acquisition in step 1 includes the following steps in sequence:

[0065] Step 11: Acquire the image;

[0066] Step 12: Determine whether the original image obtained above is an X-ray image;

[0067] Step 121: If the acquired original image is an X-ray image, request image correction;

[0068] Step 122: If the acquired original image is a dark field image, regenerate the offset correction data and request image correction using the updated offset correction data;

[0069] Step 13: In step 121 or step 122 above, simultaneously request image correction using gain correction data and bad pixel / bad line correction data;

[0070] Step 14: Obtain a clean image after the above image correction.

[0071] Preferably, in step 2, the exposure window pulse returned by the flat panel detector is divided by 1 / 2, 1 / 3, 1 / 4... 1 / N.

[0072] More preferably, in step 2, the exposure window pulse returned by the flat panel detector can also be divided into 2 / 3, 3 / 4, etc. In dual-energy applications, it is possible to acquire a frame of high-energy X-ray image, then acquire a frame of low-energy X-ray image, and finally acquire a frame of dark field image, and so on.

[0073] Preferably, in step 3, the image is an X-ray image or a dark field image.

[0074] Preferably, in step 4, the above-mentioned dark field image selection strategy uses the four dark field images closest to the X-ray image to generate offset correction data.

[0075] Preferably, the weighting configuration scheme for each dark field image frame described above adopts an average weight.

[0076] Preferably, in step 5, when setting the corresponding flat panel detector mode in the working acquisition state, the corresponding gain correction data and bad pixel / bad line correction data are loaded.

[0077] Preferably, in step 6, the aforementioned calibration file includes offset calibration data, gain calibration data, and bad pixel / bad line calibration data.

[0078] The second objective of this invention is:

[0079] An X-ray flat panel detector timing synchronization and correction system, which performs the timing synchronization and correction system as described in any one of claims 1 to 8.

[0080] The first embodiment of the present invention: a method for timing synchronization and correction of an X-ray flat panel detector.

[0081] The steps are as follows:

[0082] like Figure 1 ,

[0083] Step 1: Acquire images using a flat panel detector without any calibration. Calibration will be performed on the acquisition workstation.

[0084] Step 2: Provide a timing control module, which sends a main synchronization pulse to the detector's synchronization interface to control the detector's operating frequency (such as 15fps, 30fps, 60fps, etc.).

[0085] On the other hand, the exposure window pulses returned by the detector are divided into frequencies according to application requirements, such as 1 / 2 frequency division, 1 / 3 frequency division, 1 / 4 frequency division, etc.

[0086] The frequency-divided secondary synchronization pulse is sent to the high-voltage generator interface to control the X-ray beam output and exposure.

[0087] Figure 4 For the timing control of traditional X-ray detectors, where:

[0088] The main pulse is the main pulse issued by the timing control.

[0089] X-window is the exposure window pulse fed back by the detector;

[0090] X-Pulse is a timing control pulse sent to the high-voltage generator based on the exposure window for X-ray beam control.

[0091] Figure 5 To design a new timing control for this invention, a gate is added, which gates the frequency division of the main pulse (the figure shows the case of a 2-way frequency division).

[0092] X-window is the exposure window pulse fed back by the detector;

[0093] X-Pulse is a timing control pulse sent to the high-voltage generator based on the exposure window and gating status to control the X-ray beam output.

[0094] In traditional X-ray detector timing control, each frame of the X-window is an X-ray image.

[0095] In the newly designed timing control of this invention, the X-window image with the gate open is an X-ray image, and the X-window image with the gate closed is a dark field image.

[0096] Step 3: The image acquired by the detector is labeled with its attributes (X-ray image or dark field image) according to the pulse and frequency division settings controlled by the timing control module.

[0097] like Figure 6 Example of a frequency division image:

[0098] In this mode, if the detector frequency is 30fps, then the system outputs an X-ray image at a frequency of 15fps.

[0099] like Figure 7 Example of a three-way frequency response image:

[0100] In this mode, if the detector frequency is 30fps, then the system outputs an X-ray image at a frequency of 10fps.

[0101] Step 4: Perform multi-frame averaging or recursive averaging of the dark field image according to the set strategy to generate real-time offset correction data.

[0102] The selection strategy for dark field images can be configured according to system requirements. The general principle is to use the few dark field images most recent to the X-ray image to generate offset correction data. The weight of each image can also be configured. A typical approach is to use average weight. For example, when using the four most recent dark field images, the weight of each dark field image is 0.25 (1 / 4).

[0103] exist Figure 8 In the example, frame0 is the X-ray image we need to output. Assuming that the offset correction data is generated using the most recent 4 Dark Images, then we can use frame-1, frame-2, frame-4, and frame-5; or we can use frame1, frame-1, frame-2, and frame-4. In this case, we need to wait for frame1 to be acquired before we can calculate and output the corrected image of frame0.

[0104] Step 5: If in calibration mode, the pre-defined detector mode (corresponding to detector internal gain parameters, detector readout binding settings, detector FOV settings, etc.) can be used to acquire Flat X-ray images and dark-field images simultaneously, generating corresponding gain correction data (gain map) and bad pixel / line correction data (pixel / line map). These two sets of data are saved to the calibration file corresponding to that mode. When the system is in active acquisition mode and the corresponding detector mode is set, the corresponding gain correction data and bad pixel / line correction data are loaded.

[0105] Step 6: In the working state, since the correction files (offset map, gain map, pixel / line map) are already available, the correction of each frame of the image can be completed according to the traditional correction algorithm.

[0106] like Figure 2 In the traditional work mode, the offset map needs to be prepared in advance;

[0107] like Figure 3 In the working mode of this invention, the Offset Map is generated and refreshed in real time;

[0108] Gain Map and Pixel / Line Map are relatively stable for each detector mode and usually only need to be refreshed / updated once every 3 months or more.

[0109] exist Figure 9 In the example of dynamically switching the system output frequency, it is assumed that the detector frequency remains constant at 30fps, but the frequency of the system output X-ray image changes from 15fps to 10fps without any pause.

[0110] This method reduces the effective image output frequency of the detector by a minimum of 1 time. Considering that current detectors can achieve acquisition frequencies of over 60 fps, while practical applications typically operate below 30 fps, the benefits of this approach for practical applications are significant.

[0111] Furthermore, this algorithm requires real-time updates to the offset correction data, placing high demands on computational performance. Given the high performance of GPUs today, all calculations can be performed on the GPU. This invention does not limit the computational module; whether the solution is implemented on a GPU or a CPU, it is within the scope of this invention.

[0112] The detector timing synchronization and correction scheme of the present invention can be integrated into the detector (including the timing synchronization scheme and correction strategy). This integration into the detector is also within the scope of the present invention. In this case, the external control system inputs the main pulse to the detector, and the detector internally performs frequency division according to the mode configuration. The output X-window (detector feedback exposure window pulse) is the result of the frequency division, and the output image is only an X-ray image (usually the corrected result, depending on the configuration).

[0113] This invention enables real-time updates of offset correction data (Offset Map), eliminating the need for periodic (every 10-30 minutes) updates. Due to the unique nature of dynamic systems (RF / CathLab), the triggered detector modes are unpredictable, necessitating the updating of all potentially triggered and expired offset data, resulting in complex and time-consuming logic control.

[0114] This invention enables real-time updates of offset correction data, especially by using a dark-field image immediately following an X-ray image to generate offset correction data, which can greatly solve the problem of lag in dynamic applications of X-ray flat panel detectors.

[0115] This invention can generate the corresponding working mode calibration file by performing an image acquisition once in calibration mode, making the detector calibration process simple and efficient.

[0116] In RF / CathLab applications, depending on the subject being captured, it is necessary to switch the acquisition frequency (potentially multiple times). This requires the system to prepare offset correction data (Offset Map) for all acquisition frequencies in advance. Simultaneously, when switching acquisition frequencies, acquisition needs to be stopped and the corresponding frequency's offset correction data (Offset Map) replaced (loaded). This invention enables real-time frame rate switching without stopping acquisition.

[0117] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0118] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0119] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for timing synchronization and correction of an X-ray flat panel detector, characterized in that: The steps are as follows: Step 1: Acquire images using a flat panel detector; Step 2: Through the timing control module, on the one hand, a main synchronization pulse is sent to the synchronization interface of the flat panel detector to control the operating frequency of the flat panel detector; on the other hand, the exposure window pulse returned by the flat panel detector is divided into frequencies; the frequency-divided secondary synchronization pulse is sent to the high voltage generator interface to control the X-ray beam exposure. Step 3: The image acquired by the flat panel detector in Step 1 above is marked with attributes according to the pulse and frequency division settings controlled by the timing control module. Step 4: Perform multi-frame averaging or recursive averaging of the dark field image according to the set strategy to generate real-time offset correction data. Step 5: If in calibration mode, set the flat panel detector mode, acquire X-ray images and dark field images at once, and generate corresponding gain correction data and bad pixel / bad line correction data; Step 6: In working mode, since the calibration files are already available, complete the calibration of each frame of the image.

2. The X-ray flat panel detector timing synchronization and correction method as described in claim 1, characterized in that, The image acquisition in step 1 includes the following steps in sequence: Step 11: Acquire the image; Step 12: Determine whether the original image obtained above is an X-ray image; Step 121: If the acquired original image is an X-ray image, request image correction; Step 122: If the acquired original image is a dark field image, regenerate the offset correction data and request image correction using the updated offset correction data; Step 13: In step 121 or step 122 above, simultaneously request image correction using gain correction data and bad pixel / bad line correction data; Step 14: Obtain a clean image after the above image correction.

3. The X-ray flat panel detector timing synchronization and correction method as described in claim 1, characterized in that, In step 2, the exposure window pulse returned by the flat panel detector is divided by 1 / 2, 1 / 3, 1 / 4... 1 / N.

4. The X-ray flat panel detector timing synchronization and correction method as described in claim 1, characterized in that, In step 3, the image is classified as an X-ray image or a dark field image.

5. The X-ray flat panel detector timing synchronization and correction method as described in claim 1, characterized in that, In step 4, the dark field image selection strategy described above uses the four dark field images closest to the X-ray image to generate offset correction data.

6. The X-ray flat panel detector timing synchronization and correction method as described in claim 5, characterized in that, The weighting scheme for each dark scene image frame described above uses an average weight.

7. The X-ray flat panel detector timing synchronization and correction method as described in claim 1, characterized in that, In step 5, when setting the corresponding flat panel detector mode in the working acquisition state, the corresponding gain correction data and bad pixel / bad line correction data are loaded.

8. The method for timing synchronization and correction of an X-ray flat panel detector as described in claim 1, characterized in that, In step 6, the aforementioned calibration file includes offset calibration data, gain calibration data, and bad pixel / bad line calibration data.

9. A timing synchronization and correction system for an X-ray flat panel detector, characterized in that, A timing synchronization and correction system that performs the method as described in any one of claims 1 to 8.

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