A control and health detection method, device and medium for realizing continuous and uniform sampling of a CT detector

Abstract

The application discloses a kind of to realize the control and health detection method, equipment and medium of CT detector continuous uniform sampling, method includes: sampling the current pulse signal convert of CT system, real-time update history window;According to history window, calculate jitter range threshold value;The length average Length_average of all pulse signals convert in updated history window is calculated, and first threshold T1 and second threshold T2 are obtained;Health detection is carried out to current pulse signal convert, if it is judged as healthy, then with current pulse signal convert continue to carry out signal sampling and output backward, send into detector, if it is judged as unhealthy, then according to jitter range threshold value, boundary truncation is carried out to current pulse signal convert, realizes that pulse signal uniform sampling control is sent into detector after.The application realizes health monitoring, reflects whether the speed of machine is stable, and slip ring health state.

Description

Technical Field

[0001] This invention relates to the field of medical device signal processing technology, and in particular to a control method, device and medium for achieving continuous and uniform sampling of CT detectors and health monitoring. Background Technology

[0002] Currently, most detectors used in clinical CT are energy integration detectors. Their sampling mechanism is charge integration window sampling, which accumulates photon charge within time T. Each time the CT rotates one view (projection angle), a complete integration is completed. For each view rotation, the detector receives a convert signal. This convert signal triggers the detector to open the integration window and output the integrated data for the previous convert time period. The convert signal is a frame-level synchronization timing trigger pulse sent by the CT gantry angle encoding system to the detector to read the chip integration data. It corresponds to the acquisition boundary marker of a single view and is the sole synchronization reference signal for the energy integration detector's charge integration window switching, integration charge readout, and integrator reset.

[0003] In CT systems, the converter signal is generally generated based on the A and B phase signals output by the encoder or driver. Using the driver to output the A and B phase signals is low-cost, but due to the mechanical transmission system, the position information error is relatively large. For each view rotation of the CT, a certain number of A and B phase signals are generated. The length of the converter signal is determined by measuring the number of A and B phase signals. For a CT system rotating at a constant speed, the converter length is uniform. For the detector, the ideal converter signal is a square wave signal. The rising and falling edges of the converter trigger the detector to open the integration window and output the integrated data of the previous converter time length. It can reflect the current true angle of the CT and ensure that the detector can achieve continuous and uniform sampling. Due to mechanical transmission and transmission errors (mainly from slip rings), the converter signal received by the detector is not a square wave. When the jitter is too large, it directly leads to inconsistent X-ray integration time and sampling misalignment under the same projection angle. For dual-energy scanning, the accuracy requirements for converter are even more stringent. Excessive converter jitter will directly lead to the failure of dual-energy scanning. Summary of the Invention

[0004] Technical objective: In view of the deficiencies in the prior art, this invention discloses a control method, equipment and medium for continuous and uniform sampling of CT detectors, which can monitor the operating status of the CT system and reflect whether the machine's rotation speed is stable and the health status of the slip ring.

[0005] Technical solution: To achieve the above technical objectives, the present invention adopts the following technical solution.

[0006] A method for controlling and monitoring the health of a CT detector to achieve continuous and uniform sampling includes the following steps: STEP 1: Sample the current pulse signal of the CT system and convert it, and update the historical window in real time; Sample the length information of the pulse signal conversion of the CT system in real time, and update the historical window with the current pulse signal conversion length information as the endpoint in real time. STEP2: Calculate the jitter range threshold based on the historical window; calculate the average length of all pulse signals converted in the updated historical window (Length_average), and obtain the first threshold T1 and the second threshold T2; construct the jitter range threshold [Length_average-T1, Length_average+T2] using the average length of converted, the first threshold T1, and the second threshold T2. STEP3: Perform a health check on the current pulse signal convert. If it is determined to be healthy, continue to sample the current pulse signal convert and output it to the detector. If it is determined to be unhealthy, perform uniform sampling control of the pulse signal and proceed to STEP4. STEP4: Based on the jitter range threshold, the current pulse signal is truncated at the boundary to achieve uniform sampling control of the pulse signal before it is sent to the detector.

[0007] Furthermore, the pulse signal convert is generated by the A-phase and B-phase signals output by the encoder or driver; for each rotation of the CT by one projection angle view, a certain number of A-phase and B-phase signals are generated, and the length of the convert signal is determined by measuring the number of A-phase and B-phase signals.

[0008] Furthermore, a health check is performed on the current pulse signal convert, including: determining whether the length of the current pulse signal convert is within the jitter range threshold; if so, it is considered healthy; otherwise, it is considered unhealthy.

[0009] Furthermore, the current pulse signal convert is truncated according to the jitter range threshold, including: when the length of the current pulse signal convert is not within the jitter range threshold, the two boundary time points of the jitter range threshold are output to the detector; when the convert signal becomes shorter and arrives earlier and exceeds the jitter range threshold, the minimum value of the jitter range threshold is used as the output signal; when the convert signal becomes longer and arrives later and exceeds the predetermined jitter range, the maximum value of the jitter range threshold is output.

[0010] Furthermore, the process of obtaining the first threshold T1 and the second threshold T2 includes: The maximum jitter of the pulse signal convert is obtained based on the CT value deviation K. Based on maximum jitter Obtain the first threshold T1 and the second threshold T2.

[0011] Furthermore, the maximum jitter The calculation formulas include: , in, K represents the preset water model uniformity deviation; K represents the CT value deviation. This represents the total rotation time of a single turn of the CT slip ring. This represents the total number of converts per revolution of the CT slip ring.

[0012] Furthermore, the first threshold T1 and the second threshold T2 are equal and equal to the maximum jitter amount. Half of; or the first threshold T1 and the second threshold T2 are equal, and the maximum jitter is reached. The rotation angle is calculated and obtained from the CT scan.

[0013] Furthermore, The formulas for calculating the first threshold T1 and the second threshold T2 are: , in, This represents the rotation angle of the current CT scan.

[0014] The present invention also discloses an electronic device, the device comprising: a memory for storing a computer program; and a processor for executing the computer program to enable the device to perform any of the above-described control and health detection methods for achieving continuous uniform sampling of a CT detector.

[0015] The present invention also discloses a computer storage medium on which a computer program is stored. When the computer program is run, the device running the computer program implements any of the above-described methods for controlling and monitoring the continuous and uniform sampling of a CT detector.

[0016] Beneficial effects: 1. This invention can monitor the operating status of a CT system, reflecting whether the machine's rotation speed is stable and the health status of the slip rings. 2. This invention can reduce the number of rotary encoders used in CT systems. Since both the encoder and the driver in this invention can provide A and B phase signals, the conversion signal generated by using the A and B phase signals generated by the driver has relatively low accuracy. However, by using the method of this invention, the sampling accuracy requirements of the equipment can be met, and the machine cost can be reduced. 3. This invention can define the jitter range of its trigger signal convert according to the characteristics of the detector. After precisely adjusting the length of the convert signal used to trigger the acquisition of detector data, the detector can achieve continuous and uniform sampling, improve data accuracy and image quality, and meet the high-quality requirements of convert during dual-energy scanning. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the homogenization process of converter according to the present invention; Figure 2 This is a schematic diagram illustrating the system health detection method of the present invention; Figure 3 This is a flowchart of a method for controlling and monitoring the health of a CT detector to achieve continuous and uniform sampling, according to the present invention. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0019] Example: As attached Figure 1 and attached Figure 3 As shown, this embodiment of a method for controlling and monitoring the health of a CT detector to achieve continuous and uniform sampling includes the following steps: STEP 1: Sample the current pulse signal conversion of the CT system and update the history window in real time; sample the length information of the pulse signal conversion of the CT system in real time and update the history window with the current pulse signal conversion length information as the endpoint in real time; the history window includes a preset number of pulse signal conversions, and when a new conversion length information arrives, the oldest stored conversion length information is removed. The pulse signal convert is generated by the A-phase and B-phase signals output by the encoder or driver. For each rotation of the CT by one projection angle view, a certain number of A-phase and B-phase signals are generated. The length of the convert signal is determined by measuring the number of A-phase and B-phase signals. STEP2: Calculate the jitter range threshold based on the historical window; calculate the average length of all pulse signals converted in the updated historical window (Length_average), and obtain the first threshold T1 and the second threshold T2; construct the jitter range threshold [Length_average-T1, Length_average+T2] using the average length of converted, the first threshold T1, and the second threshold T2. STEP 3: Perform a health check on the current pulse signal converter. If it is determined to be healthy, continue sampling the current pulse signal converter and output it to the detector. If it is determined to be unhealthy, perform uniform sampling control of the pulse signal and proceed to STEP 4: Perform a health check on the current pulse signal converter, including: determining whether the length of the current pulse signal converter is within the jitter range threshold. If yes, it is determined to be healthy; otherwise, it is determined to be unhealthy. Furthermore, this invention can also determine whether there is a mechanical rotation fault or slip ring fault in the CT system during use. The pulse signal converter needs to pass through a slip ring during transmission in the CT system. Before entering the slip ring, a judgment on mechanical rotation instability can be given. If instability exists, it is processed. For example, if the rotation error received by the system during mechanical rotation is 1%, then the error caused by the mechanical rotation received by the converter is... , This represents the total rotation time of a single turn of the CT slip ring. This represents the total number of converts per revolution of the CT slip ring. When the detected deviation of the actual convert length exceeds twice this error, i.e., the length exceeds... If the mechanical rotation is unstable, and after the converter is output from the slip ring, an additional level of converter detection is added. If the data transmission time on the slip ring is Ts, then if the difference between the two converters after the converter is detected to be output from the slip ring is greater than 3Ts, the slip ring is considered to have a problem.

[0020] STEP 4: Truncate the current pulse signal convert according to the jitter range threshold to achieve uniform sampling control before sending it to the detector. This truncation includes: when the length of the current pulse signal convert is not within the jitter range threshold, outputting it to the detector at the two boundary points of the jitter range threshold; when the convert signal becomes shorter and arrives earlier than the jitter range threshold, using the minimum value of the jitter range threshold as the output signal, i.e., using the time Length_average-T1 as the trigger signal for the detector; when the convert signal becomes longer and arrives later than the predetermined jitter range, outputting it to the detector at the maximum value of the jitter range threshold, i.e., using the time Length_average+T2 as the trigger signal for the detector.

[0021] In this embodiment, before the signal is sent to the detector, the average value of multiple consecutive convert signals stored at present can be calculated as a reference value and denoted as Length_average. Based on the required jitter range selected by the detector, i.e., using Length_average as the reference point, a jitter range is established with Length_average-T1 and Length_average+T2 as boundaries. When the received convert signal is within this range, the received convert signal is used as the trigger signal for the detector. When the convert signal becomes shorter and arrives earlier and exceeds Length_average-T1, the time of Length_average-T1 is used as the trigger signal for the detector. When the convert signal becomes longer and arrives later and exceeds Length_average+T2, the time of Length_average+T2 is used as the trigger signal for the detector.

[0022] In this embodiment, the process of obtaining the first threshold T1 and the second threshold T2 includes: The maximum jitter of the pulse signal converter is obtained based on the CT value deviation K. : , in, K represents the preset water model uniformity deviation; K represents the CT value deviation. This represents the total rotation time of a single turn of the CT slip ring. This represents the total number of converts per revolution of the CT slip ring.

[0023] Based on maximum jitter Obtain the first threshold T1 and the second threshold T2. At this point, the first threshold T1 and the second threshold T2 are equal and represent the maximum jitter. Half of; or the first threshold T1 and the second threshold T2 are equal, and the maximum jitter is reached. The CT rotation angle is calculated; the calculation formula is: , in, This represents the current rotation angle of the CT scan. Compared to the first method, the second method requires more computation but achieves better uniformity. The above are only the minimum standards to meet system requirements; in practical applications, these standards can be increased based on specific needs.

[0024] The example calculation in this embodiment is as follows: The national standard specifies a maximum permissible error of 4 HU for the uniformity of the entire water model. We take the CT deviation caused by converter vibration to be no more than 10% of the permissible uniformity error of the entire model. The maximum jitter of the converter is 0.4 HU. If the CT value deviation is K for every 1% change in the converter signal, and the unit is HU, then the maximum jitter of the converter is... Should meet: , in, The standard integration time for convert is calculated as follows: , in, This represents the total rotation time of a single turn of the CT slip ring. This represents the total number of converters in one revolution of the CT slip ring. Therefore: , When determining the values ​​of T1 and T2, we have two options. The first option is to select... Another method is to determine the rotation speed based on the location of the CT scanner. Since the X-ray tube is a relatively heavy component on the CT scanner gantry, it can cause fluctuations in rotation speed. ,in, The rotation angle of the current CT scan is given. For each additional convert step, the rotation angle increases by [value missing]. Using this method requires increased computation, but it yields better uniformity. The above are only the minimum standards to meet system requirements; in practical applications, these standards can be raised based on specific needs.

[0025] In other embodiments of the present invention, since mechanical rotation and slip rings are the main sources of converter jitter among the many factors causing converter jitter, the present invention can detect whether the mechanical rotation is smooth and the health status of the slip rings, as illustrated in the schematic diagram. Figure 2The detection of the converter entering and exiting the slip ring can determine the mechanical rotation and the health status of the slip ring. Specifically, before the converter enters the slip ring, the length of the currently stored converter is recorded, and a maximum and minimum deviation is defined. When the deviation exceeds this value, such as a fluctuation exceeding 10%, it indicates that the mechanical rotation speed is unstable. After the converter exits the slip ring, the maximum and minimum values ​​of the currently stored converter are recorded, and a maximum and minimum deviation is defined. When the deviation exceeds this value, it indicates that the slip ring's health status is problematic and needs to be cleaned. Since the number of slip rings is limited, multiple signals are often transmitted serially on a single ring when a signal passes through it. Therefore, under normal conditions, the maximum jitter generated by the slip ring is twice the transmission time of a single information transmission. Thus, the maximum and minimum deviation we use to determine the slip ring's health status is twice the transmission time of the serial signal on the slip ring.

[0026] This invention also discloses an electronic device, comprising: a memory for storing a computer program; and a processor for executing the computer program to cause the device to execute the aforementioned control and health detection method for achieving continuous uniform sampling of a CT detector. In this embodiment, the method of this invention is implemented using FPGA computation. Using FPGA can guarantee both computational speed and accuracy. The jitter range of the converter can be selected according to requirements to improve the uniformity of the converter and achieve continuous uniform sampling of the detector.

[0027] The present invention also provides a computer storage medium on which a computer program is stored. When the computer program is run, the device running the computer program implements the aforementioned control and health detection method for continuous and uniform sampling of a CT detector.

[0028] In the embodiments of this application, the terms "first" and "second" (if they exist) are used only as name identifiers and do not represent the order of first and second.

[0029] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that all or part of the steps in the methods of the above embodiments can be implemented by means of software plus a general-purpose hardware platform. Based on this understanding, the technical solution of this application can be embodied in the form of a software product. This computer software product can be stored in a storage medium. The memory can be various types of memory, such as random access memory, read-only memory, flash memory, etc., such as read-only memory (ROM) / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which can be a personal computer, server, or network communication device such as a router) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0030] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments. The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separate. The components indicated as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment solution according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0031] The above description is only a preferred embodiment of 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 principle 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 controlling and monitoring the health of a CT detector to achieve continuous and uniform sampling, characterized in that, Includes the following steps: STEP 1: Sample the current pulse signal of the CT system and convert it, and update the historical window in real time; Sample the length information of the pulse signal conversion of the CT system in real time, and update the historical window with the current pulse signal conversion length information as the endpoint in real time. STEP2: Calculate the jitter range threshold based on the historical window; calculate the average length of all pulse signals converted in the updated historical window (Length_average), and obtain the first threshold T1 and the second threshold T2; construct the jitter range threshold [Length_average-T1, Length_average+T2] using the average length of converted, the first threshold T1, and the second threshold T2. STEP3: Perform a health check on the current pulse signal convert. If it is determined to be healthy, continue to sample the current pulse signal convert and output it to the detector. If it is determined to be unhealthy, perform uniform sampling control of the pulse signal and proceed to STEP4. STEP4: Based on the jitter range threshold, the current pulse signal is truncated at the boundary to achieve uniform sampling control of the pulse signal before it is sent to the detector.

2. The control and health monitoring method for achieving continuous and uniform sampling of a CT detector according to claim 1, characterized in that: The pulse signal converter is generated by the A-phase and B-phase signals output by the encoder or driver. For each rotation of the CT by one projection angle, a certain number of A-phase and B-phase signals are generated. The length of the converter signal is determined by measuring the number of A-phase and B-phase signals.

3. The control and health monitoring method for achieving continuous and uniform sampling of a CT detector according to claim 1, characterized in that: A health check is performed on the current pulse signal convert, including: determining whether the length of the current pulse signal convert is within the jitter range threshold; if yes, it is considered healthy; otherwise, it is considered unhealthy.

4. The control and health monitoring method for achieving continuous and uniform sampling of a CT detector according to claim 1, characterized in that: The current pulse signal convert is truncated according to the jitter range threshold, including: when the length of the current pulse signal convert is not within the jitter range threshold, the output signal is sent to the detector at the two boundary time points of the jitter range threshold; when the convert signal becomes shorter and arrives earlier and exceeds the jitter range threshold, the minimum value of the jitter range threshold is used as the output signal; when the convert signal becomes longer and arrives later and exceeds the predetermined jitter range, the maximum value of the jitter range threshold is used as the output signal.

5. The control and health monitoring method for achieving continuous and uniform sampling of a CT detector according to claim 1, characterized in that: The process of obtaining the first threshold T1 and the second threshold T2 includes: The maximum jitter of the pulse signal convert is obtained based on the CT value deviation K. Based on the maximum jitter Obtain the first threshold T1 and the second threshold T2.

6. The control and health monitoring method for achieving continuous uniform sampling of a CT detector according to claim 5, characterized in that: Maximum jitter Calculation formula include: ， in, K represents the preset water model uniformity deviation; K represents the CT value deviation. This represents the total rotation time of a single turn of the CT slip ring. This represents the total number of converts per revolution of the CT slip ring.

7. The control and health monitoring method for achieving continuous and uniform sampling of a CT detector according to claim 5, characterized in that: The first threshold T1 and the second threshold T2 are equal and equal to the maximum jitter amount. Half of; or the first threshold T1 and the second threshold T2 are equal, and the maximum jitter is reached. The rotation angle is calculated and obtained from the CT scan.

8. The control and health monitoring method for achieving continuous uniform sampling of a CT detector according to claim 7, characterized in that: The formulas for calculating the first threshold T1 and the second threshold T2 are as follows: ， in, This represents the current rotation angle of the CT scan.

9. An electronic device, characterized in that: The device includes: a memory for storing a computer program; and a processor for executing the computer program to enable the device to perform a control and health monitoring method for continuous uniform sampling of a CT detector as described in claims 1-8.

10. A computer storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is run, the device running the computer program implements the control and health detection method for continuous uniform sampling of a CT detector as described in claims 1-8.

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