Flat panel detector full-field automatic exposure detection method and image acquisition device

Abstract

The present invention provides a full-view automatic exposure detection method for a flat-panel detector and an image acquisition device, the detection method comprising: S101: the flat-panel detector acquires image data at a fixed period when not exposed, and saves the image data in units of lines; S102: judging whether the number of frames and the corresponding number of lines of the image corresponding to the image data are both greater than one, if so, executing S103, if not, executing S101; S103: obtaining the difference between the image data and the pixel value of the previous line of image data and the corresponding line of image data of the previous frame image, judging whether the difference is greater than a preset threshold, if so, executing S104, if not, executing S101; S104: confirming that exposure occurs, and determining the moment of acquiring the image data as the moment of exposure. The present invention determines the moment of exposure through the image data acquired by the flat-panel detector, and the user does not need to pay attention to the interface timing of the high-voltage generator, so that it can be used quickly, speeding up the development progress of the product, and meeting the needs of users.

Description

Technical Field

[0001] The present invention relates to the field of image acquisition, and in particular to a full-view automatic exposure detection method for a flat panel detector and an image acquisition device. Background Art

[0002] Digital Radiography (DR) is a new X-ray photography technology developed in the 1990s. With its significant advantages such as faster imaging speed, more convenient operation, and higher imaging resolution, it has become the dominant direction of digital X-ray photography technology and has been recognized by clinical institutions and imaging experts around the world. The technical core of DR is the flat-panel detector, which is a precise and expensive device that plays a decisive role in imaging quality. The flat-panel detector is the X-ray receiving device in the DR system. In the DR system, the high-voltage generator and the tube control the output of X-rays. X-rays pass through objects and attenuate. The attenuated X-rays are converted into visible light after passing through the flat-panel detector, and then converted into electrical signals through photoelectric conversion. Then, they are converted into digital signals through the analog / digital converter (ADC) and input into the computer for processing.

[0003] X-ray flat panel detector exposure often uses the X-ray switch signal on the high-voltage generator to control the exposure of the flat panel detector. However, this method often requires the flat panel detector to be connected to the high-voltage generator, which is inconvenient to use and has poor flexibility. In addition, there are many high-voltage generator manufacturers, and the high-voltage generator interfaces of different manufacturers are also different. Therefore, when using it, users have to pay attention to the messy high-voltage generator interface timing, which makes it difficult to quickly get started during testing and trial use, delaying the development progress of the entire product and failing to meet user needs. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention proposes a full-field automatic exposure detection method for a flat-panel detector and an image acquisition device. When the high-voltage generator is not connected to the flat-panel detector, the moment when exposure occurs is determined by image data collected by the flat-panel detector, thereby solving the problems of inconvenient use and poor flexibility of the flat-panel detector. The user does not need to pay attention to the interface timing of the high-voltage generator, so that he can quickly get started and use it, which speeds up the development progress of the whole product and meets the needs of users.

[0005] To solve the above problem, a technical solution adopted by the present invention is: a full-field automatic exposure detection method for a flat-panel detector, the flat-panel detector is not connected to a high-voltage generator, and the full-field automatic exposure detection method for the flat-panel detector includes: S101: the flat-panel detector collects image data at a fixed period when not exposed, and saves the image data in units of lines; S102: judging whether the number of frames and the corresponding number of lines of the image corresponding to the image data are both greater than one, if so, executing S103, if not, executing S101; S103: obtaining the difference in pixel values ​​between the image data and the previous line of image data and the corresponding line of image data of the previous frame, judging whether the difference is greater than a preset threshold, if so, executing S104, if not, executing S101; S104: confirming that exposure occurs, and determining the moment when the image data is collected as the moment when the exposure occurs.

[0006] Furthermore, the fixed period is 300-500ms.

[0007] Furthermore, the step of collecting image data at a fixed period when the flat panel detector is not exposed specifically includes: the flat panel detector is in a self-clearing state when it is not exposed, and collects image data at a fixed period.

[0008] Furthermore, after the step of determining the moment of collecting the image data as the moment of exposure, the step also includes: the flat-panel detector pauses self-clearing, confirms the row where the image data is located as a dividing line, obtains the difference in the mean pixel values ​​of the images on both sides of the dividing line, and compensates the image according to the difference.

[0009] Furthermore, the pixel value mean is the pixel value mean of the grayscale value of the image.

[0010] Based on the same inventive concept, the present invention also proposes an image acquisition device, which includes: a flat-panel detector and a high-voltage generator, wherein the flat-panel detector and the high-voltage generator are not connected; the image acquisition device executes the flat-panel detector full-field automatic exposure detection method described below to detect exposure: S201: control the flat-panel detector to acquire image data at a fixed period when not exposed, and save the image data in units of rows; S202: determine whether the number of frames and the number of rows of the image corresponding to the image data are both greater than one, if so, execute S203, if not, execute S201; S203: obtain the difference in pixel values ​​between the image data and the previous row of image data and the corresponding row of image data of the previous frame, determine whether the difference is greater than a preset threshold, if so, execute S204, if not, execute S201; S204: confirm that exposure occurs, and determine the moment when the image data is acquired as the moment when the exposure occurs.

[0011] Furthermore, the fixed period is 300-500ms.

[0012] Furthermore, the step of collecting image data at a fixed period when the flat panel detector is not exposed specifically includes: the flat panel detector is in a self-clearing state when it is not exposed, and collects image data at a fixed period.

[0013] Furthermore, after the step of determining the moment of collecting the image data as the moment of exposure, the step also includes: the flat-panel detector pauses self-clearing, confirms the row where the image data is located as a dividing line, obtains the difference in the mean pixel values ​​of the images on both sides of the dividing line, and compensates the image according to the difference.

[0014] Furthermore, the pixel value mean is the pixel value mean of the grayscale value of the image.

[0015] Compared with the prior art, the beneficial effect of the present invention is that when the high-voltage generator is not connected to the flat-panel detector, the moment of exposure is determined by the image data collected by the flat-panel detector, which solves the problem of inconvenient use and poor flexibility of the flat-panel detector. The user does not need to pay attention to the interface timing of the high-voltage generator, so that he can quickly get started and use it, which speeds up the development progress of the whole product and meets the needs of users. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flow chart of an embodiment of a method for full-field automatic exposure detection of a flat panel detector of the present invention;

[0017] Figure 2 It is a structural diagram of an embodiment of an image acquisition device of the present invention;

[0018] Figure 3 The present invention is a flowchart of an embodiment of a method for detecting full-field automatic exposure of a flat-panel detector executed by an image acquisition device of the present invention. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0020] See also Figure 1 ,in, Figure 1 FIG. 1 is a flow chart of an embodiment of a method for automatically detecting full-field exposure of a flat panel detector according to the present invention. Figure 1 The full-field automatic exposure detection method of the flat-panel detector of the present invention is described in detail.

[0021] In this embodiment, the flat panel detector is not connected to the high voltage generator, and the full-view automatic exposure detection method of the flat panel detector includes:

[0022] S101: The flat panel detector collects image data at a fixed period when not exposed, and saves the image data in units of lines.

[0023] The flat panel detector is in a self-clearing state when not exposed and collects image data at a fixed period.

[0024] In this embodiment, the flat panel detector is an X-ray flat panel detector.

[0025] In this embodiment, the flat panel detector collects image data in a period of 300-500 ms.

[0026] In this embodiment, the image data collected by the flat panel detector is a dark field image of the collected image, and each frame of the collected dark field image is analyzed and saved in units of lines.

[0027] In this embodiment, the flat panel detector collects and stores image data in units of lines.

[0028] S102: Determine whether the number of frames and the number of rows of the image corresponding to the image data are both greater than one, if so, execute S103, if not, execute S101;

[0029] In this embodiment, in order to improve the detection sensitivity, the flat panel detector uses two comparisons to detect whether exposure occurs.

[0030] When the flat panel detector collects image data and saves the image data in units of lines, it is determined whether the frame number and the corresponding line number of the image corresponding to the line of image data are both greater than 1, that is, exposure detection begins at the second line of image data of the second frame of the collected image.

[0031] S103: Obtain the pixel value differences between the image data and the previous row of image data and the corresponding row of image data of the previous frame image, and determine whether the differences are greater than a preset threshold. If so, execute S104; if not, execute S101;

[0032] In this embodiment, the pixel value is the average pixel value of the grayscale value of a row of image data, and the difference is the difference between the average pixel value of the grayscale value of the row of image data and the average pixel value of the grayscale value of the previous row of image data and the average pixel value of the grayscale value of the corresponding row of image data in the previous frame of image. The difference is used to determine whether the high voltage generator emits radiation and thus exposure occurs.

[0033] In this embodiment, the value of the preset threshold value can be set according to the type and detection capability of the flat panel detector. It only needs to be able to detect whether exposure occurs according to the preset threshold value, and no limitation is made here.

[0034] In a specific embodiment, the flat-panel detector is in a self-clearing state when in an idle state. During the self-clearing process, the pixel value of the row is calculated in units of rows for the image data collected by the detector and saved. When the second row is collected, the data value of the second row is compared with the saved data value of the first row to determine whether the difference between the data values ​​of the two rows is greater than a preset threshold. While comparing adjacent rows, it is also necessary to compare with the pixel value of the corresponding row of the previous frame. If the difference between the two comparisons is greater than a preset threshold at the same time, it is considered that exposure has occurred. This approach can eliminate the situation where false triggering is caused by vibration. The experiment concluded that the false triggering caused by vibration is a slowly changing process in the current frame, while the value caused by exposure is a relatively large change.

[0035] S104: confirming that exposure occurs, and determining the time when image data is collected as the time when exposure occurs.

[0036] After confirming that exposure has occurred, the flat panel detector sends the time when the exposure occurred to the corresponding device, thereby minimizing the loss of exposure dose after the exposure occurs.

[0037] Since the flat panel detector will stop self-clearing once it detects exposure in the self-clearing state, the dark field accumulation values ​​of the upper and lower halves of the collected image data will be different, resulting in image splitting. Therefore, it is necessary to compensate for one half of the image to achieve the purpose of image integrity.

[0038] In this embodiment, after the step of determining the moment of collecting image data as the moment of exposure, the step also includes: the flat-panel detector pauses to clear itself, confirms the row where the image data is located as the dividing line, obtains the difference in the mean pixel value of the image on both sides of the dividing line, and compensates the image according to the difference.

[0039] In this embodiment, the pixel value average is the pixel value average of the grayscale values ​​of the images on both sides of the dividing line.

[0040] In this embodiment, when compensating the image according to the difference, the average pixel value of the image on both sides of the dividing line is obtained, and the difference is compensated for each pixel in the image with a smaller average pixel value, and the compensated image data is transmitted to the host computer. In this way, the image is complete and there is no obvious transition zone.

[0041] The present invention compares the collected image data in units of lines with the adjacent previous line of image data and the corresponding line of image data of the previous frame, thereby improving the detection sensitivity and being able to effectively trigger the flat-panel detector when the area on which the X-ray output by the high-voltage generator acts on the flat-panel detector is relatively small, thereby detecting exposure and achieving the purpose of full-field detection without having to set the size and position of the beam window.

[0042] The flat panel detector full-field automatic exposure detection method of the present invention has the following advantages:

[0043] 1. The full-view AED mode allows users to fully capture images without connecting the flat-panel detector and high-voltage generator.

[0044] 2. The full-view AED mode has no requirements for the position and size of the exposure window, which increases ease of use.

[0045] 3. No independent detection module is added, which reduces the complexity of the system and improves the stability of the system.

[0046] 4. Image compensation algorithm can make the image complete and of high quality.

[0047] Beneficial effect: The flat-panel detector full-field automatic exposure detection method of the present invention determines the moment of exposure through image data collected by the flat-panel detector when the high-voltage generator is not connected to the flat-panel detector, thereby solving the problems of inconvenient use and poor flexibility of the flat-panel detector. The user does not need to pay attention to the interface timing of the high-voltage generator, so that he can quickly get started and use it, which speeds up the development progress of the whole product and meets the needs of users.

[0048] Based on the same inventive concept, the present invention also proposes an image acquisition device, see Figure 2 , Figure 3 , Figure 2 is a structural diagram of an embodiment of an image acquisition device of the present invention, Figure 3 The present invention is a flowchart of an embodiment of a method for automatically detecting exposure of a flat panel detector executed by an image acquisition device. Figure 2 , Figure 3 The image acquisition device of the present invention is described in detail.

[0049] In this embodiment, the image acquisition device includes: a flat panel detector and a high voltage generator, and there is no connection between the flat panel detector and the high voltage generator; the image acquisition device performs the following flat panel detector full-field automatic exposure detection method to detect exposure:

[0050] S201: Control the flat panel detector to collect image data at a fixed period when not exposed, and save the image data in units of lines.

[0051] The flat panel detector is in a self-clearing state when not exposed and collects image data at a fixed period.

[0052] In this embodiment, the flat panel detector is an X-ray flat panel detector.

[0053] In this embodiment, the flat panel detector collects image data in a period of 300-500 ms.

[0054] In this embodiment, the image data collected by the flat panel detector is a dark field image of the collected image, and each frame of the collected dark field image is analyzed and saved in units of lines.

[0055] In this embodiment, the flat panel detector collects and stores image data in units of lines.

[0056] S202: Determine whether the number of frames and the number of rows of the image corresponding to the image data are both greater than one, if so, execute S203, if not, execute S201;

[0057] In this embodiment, in order to improve the detection sensitivity, the flat panel detector uses two comparisons to detect whether exposure occurs.

[0058] When the flat panel detector collects image data and saves the image data in units of lines, it is determined whether the frame number and the corresponding line number of the image corresponding to the line of image data are both greater than 1, that is, exposure detection begins at the second line of image data of the second frame of the collected image.

[0059] S203: Obtain pixel value differences between the image data and the previous row of image data and the corresponding row of image data of the previous frame image, and determine whether the differences are greater than a preset threshold. If so, execute S204; if not, execute S201;

[0060] In this embodiment, the pixel value is the average pixel value of the grayscale value of a row of image data, and the difference is the difference between the average pixel value of the grayscale value of the row of image data and the average pixel value of the grayscale value of the previous row of image data and the average pixel value of the grayscale value of the corresponding row of image data in the previous frame of image. The difference is used to determine whether the high voltage generator emits radiation and thus exposure occurs.

[0061] In this embodiment, the value of the preset threshold value can be set according to the type and detection capability of the flat panel detector. It only needs to be able to detect whether exposure occurs according to the preset threshold value, and no limitation is made here.

[0062] In a specific embodiment, the flat-panel detector is in a self-clearing state when in an idle state. During the self-clearing process, the pixel value of the row is calculated in units of rows for the image data collected by the detector and saved. When the second row is collected, the data value of the second row is compared with the saved data value of the first row to determine whether the difference between the data values ​​of the two rows is greater than a preset threshold. While comparing adjacent rows, it is also necessary to compare with the pixel value of the corresponding row of the previous frame. If the difference between the two comparisons is greater than a preset threshold at the same time, it is considered that exposure has occurred. This approach can eliminate the situation where false triggering is caused by vibration. The experiment concluded that the false triggering caused by vibration is a slowly changing process in the current frame, while the value caused by exposure is a relatively large change.

[0063] S204: Confirm that exposure occurs, and determine the time when image data is collected as the time when exposure occurs.

[0064] After confirming that exposure has occurred, the flat panel detector sends the time when the exposure occurred to the corresponding device, thereby minimizing the loss of exposure dose after the exposure occurs.

[0065] Since the flat panel detector will stop self-clearing once it detects exposure in the self-clearing state, the dark field accumulation values ​​of the upper and lower halves of the collected image data will be different, resulting in image splitting. Therefore, it is necessary to compensate for one half of the image to achieve the purpose of image integrity.

[0066] In this embodiment, after the step of determining the moment of collecting image data as the moment of exposure, the step also includes: the flat-panel detector pauses to clear itself, confirms the row where the image data is located as the dividing line, obtains the difference in the mean pixel value of the image on both sides of the dividing line, and compensates the image according to the difference.

[0067] In this embodiment, the pixel value average is the pixel value average of the grayscale values ​​of the images on both sides of the dividing line.

[0068] In this embodiment, when compensating the image according to the difference, the average pixel value of the image on both sides of the dividing line is obtained, and the difference is compensated for each pixel in the image with a smaller average pixel value, and the compensated image data is transmitted to the host computer. In this way, the image is complete and there is no obvious transition zone.

[0069] The present invention compares the collected image data in units of lines with the adjacent previous line of image data and the corresponding line of image data of the previous frame, thereby improving the detection sensitivity and being able to effectively trigger the flat-panel detector when the area on which the X-ray output by the high-voltage generator acts on the flat-panel detector is relatively small, thereby detecting exposure and achieving the purpose of full-field detection without having to set the size and position of the beam window.

[0070] The flat panel detector full-field automatic exposure detection method of the present invention has the following advantages:

[0071] 1. The full-view AED mode allows users to fully capture images without connecting the flat-panel detector and high-voltage generator.

[0072] 2. The full-view AED mode has no requirements for the position and size of the exposure window, which increases ease of use.

[0073] 3. No independent detection module is added, which reduces the complexity of the system and improves the stability of the system.

[0074] 4. Image compensation algorithm can make the image complete and of high quality.

[0075] Beneficial effect: When the high-voltage generator is not connected to the flat-panel detector, the image acquisition device of the present invention determines the moment when exposure occurs through the image data collected by the flat-panel detector, thereby solving the problem of inconvenient use and poor flexibility of the flat-panel detector. The user does not need to pay attention to the interface timing of the high-voltage generator, so that he can quickly get started and use it, which speeds up the development progress of the whole product and meets the needs of users.

[0076] In the several embodiments provided by the present invention, it should be understood that the disclosed devices, modules and circuits can be implemented in other ways. For example, the device implementation described above is only schematic. For example, the structural device division of the module is only a logical function division. There may be other division methods in actual implementation, such as multiple modules can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interface, device or, which can be electrical, mechanical or other forms.

[0077] The components described as separate components may or may not be physically separated, and the components shown may or may not be physical, that is, they may be located in one place or distributed in multiple locations. Some or all of them may be selected according to actual needs to achieve the purpose of this embodiment.

[0078] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A method for full-field automatic exposure detection of a flat panel detector, characterized in that: The flat panel detector is not connected to the high voltage generator, and the flat panel detector full-view automatic exposure detection method includes: S101: The flat panel detector collects image data at a fixed period when not exposed, and saves the image data in units of lines; S102: Determine whether the number of frames and the number of rows of the image corresponding to the image data are both greater than one, if so, execute S103, if not, execute S101; S103: Obtain the difference between the pixel values ​​of the image data and the previous row of image data and the corresponding row of image data of the previous frame, and determine whether the difference is greater than a preset threshold. If so, execute S104; if not, execute S101; S104: confirming that exposure occurs, and determining the time when the image data is collected as the time when the exposure occurs.

2. The full-field automatic exposure detection method of a flat panel detector according to claim 1, characterized in that: The fixed period is 300-500ms.

3. The full-field automatic exposure detection method of a flat panel detector according to claim 1, characterized in that: The step of collecting image data at a fixed period when the flat panel detector is not exposed specifically includes: The flat panel detector is in a self-clearing state when not exposed, and collects image data at a fixed period.

4. The full-field automatic exposure detection method of a flat panel detector as claimed in claim 3, characterized in that: After the step of determining the moment of collecting the image data as the moment of exposure, the step further includes: The flat panel detector pauses self-clearing, identifies the row where the image data is located as a boundary line, obtains the difference in the mean values ​​of pixel values ​​of the images on both sides of the boundary line, and compensates the image according to the difference.

5. The full-field automatic exposure detection method of a flat panel detector as claimed in claim 4, characterized in that: The pixel value mean is the average value of the grayscale values ​​of the image.

6. An image acquisition device, characterized in that: The image acquisition device comprises: a flat panel detector and a high voltage generator, wherein there is no connection between the flat panel detector and the high voltage generator; The image acquisition device performs the following flat panel detector full-field automatic exposure detection method to detect exposure: S201: Control the flat panel detector to collect image data at a fixed period when not exposed, and save the image data in units of lines; S202: Determine whether the number of frames and the number of rows of the image corresponding to the image data are both greater than one, if so, execute S203, if not, execute S201; S203: Obtain the difference between the pixel values ​​of the image data and the previous row of image data and the corresponding row of image data of the previous frame, and determine whether the difference is greater than a preset threshold. If so, execute S204; if not, execute S201; S204: confirming that exposure occurs, and determining the time when the image data is collected as the time when the exposure occurs.

7. The image acquisition device according to claim 6, characterized in that: The fixed period is 300-500ms.

8. The image acquisition device according to claim 6, characterized in that: The step of collecting image data at a fixed period when the flat panel detector is not exposed specifically includes: The flat panel detector is in a self-clearing state when not exposed, and collects image data at a fixed period.

9. The image acquisition device according to claim 8, characterized in that: After the step of determining the moment of collecting the image data as the moment of exposure, the step further includes: The flat panel detector pauses self-clearing, identifies the row where the image data is located as a boundary line, obtains the difference in the mean values ​​of pixel values ​​of the images on both sides of the boundary line, and compensates the image according to the difference.

10. The image acquisition device according to claim 9, characterized in that: The pixel value mean is the pixel value mean of the grayscale values ​​of the image.

Images