An image stitching system and method for a mobile c-arm, electronic device

Abstract

The application provides an image splicing system and method for a mobile C-arm, and an electronic device, comprising: a transverse movement unit arranged on an image chain assembly of the mobile C-arm, used to drive the image chain assembly to move linearly in the transverse direction, the image chain assembly comprising an X-ray ball tube and a flat panel detector; a control unit in communication connection with the transverse movement unit, used to control the transverse movement unit to move the image chain assembly to a plurality of target acquisition positions according to a movement planning path; and an image processing unit in communication connection with the control unit and the flat panel detector, used to perform image acquisition at the plurality of target acquisition positions and perform splicing processing on the acquired sequence images. The application overcomes the traditional manual or whole-machine moving positioning mode, and the image chain is driven by the built-in transverse movement unit, so that the movement of the image chain is fast, stable and the position can be accurately reproduced, and the operation difficulty and collision risk are greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of image stitching for mobile C-arms, and more specifically to an image stitching system and method, and an electronic device for mobile C-arms. Background Technology

[0002] With the advancement of minimally invasive and precise orthopedic surgery, mobile C-arm X-ray machines have become core equipment for intraoperative image guidance due to their superior mobility and real-time imaging capabilities. In surgeries such as spinal correction and internal fixation of long bone fractures, it is often necessary to stitch together multiple adjacent two-dimensional fluoroscopic images or three-dimensional reconstructed data sequences to assess implant placement, observe force lines, or obtain panoramic images beyond the field of view of a single projection. However, existing technologies, from image acquisition to final stitching, suffer from a series of systemic defects when applied to mobile C-arms, severely restricting the efficient and safe clinical application of this technology.

[0003] Firstly, in the image acquisition stage, there is a lack of a high-precision and reversible automatic displacement control scheme that matches the characteristics of mobile C-arm devices. Currently, the mainstream method for acquiring sequential images relies on manually pushing the entire C-arm device or manipulating its limited mechanical joints for multiple positioning operations. This method is highly dependent on operator experience and ground conditions for positioning accuracy, resulting in irregular overlapping areas between adjacent images, unknown displacement parameters, and an inability to achieve precise path planning and origin resetting. While there are solutions that use electric wheels at the bottom of the device for driving, this essentially involves moving the entire device on the ground. On soft surfaces in the operating room, this can easily lead to slippage and encoder feedback inaccuracies, failing to meet the high-precision, repeatable linear displacement requirements of the image chain relative to the patient's anatomy. This lack of precision in the acquisition stage creates fundamental difficulties for subsequent image matching.

[0004] Secondly, in the image processing and stitching stages, existing algorithms generally suffer from inefficiency and reliability issues due to the lack of prior positional information. Because accurate and reliable device displacement data cannot be obtained from the acquisition stage, existing image stitching algorithms typically can only handle images with large overlap areas, or require feature point extraction and matching operations within a very large search range. This process is computationally intensive and difficult to meet the real-time requirements of intraoperative procedures. More importantly, when the overlap area between sequential images is small, texture features are not obvious, or geometric distortion exists, mismatches are prone to occur, leading to stitching errors or process interruptions. Furthermore, existing processes cannot achieve optimized control of radiation dose. To ensure sufficient images for subsequent screening and stitching, operators often tend to acquire more images or perform multiple exposures at the same location to obtain the best image, exposing patients to additional ionizing radiation risks. Finally, existing technical solutions lack end-to-end automated integration from command input to image output. Image acquisition, device displacement control, image processing, and stitching are usually performed independently by different subsystems, requiring frequent operator intervention, increasing operational complexity, and failing to achieve one-click or automated panoramic imaging.

[0005] Therefore, there is an urgent need in this field for a complete system and method that is deeply integrated into a mobile C-arm device, capable of achieving high-precision and controllable displacement of the imaging chain, and using displacement information to intelligently guide image acquisition and accelerate image stitching, so as to systematically solve the aforementioned clinical pain points in terms of accuracy, efficiency, radiation safety and ease of operation.

[0006] Therefore, existing technologies still need further development. Summary of the Invention

[0007] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide an image stitching system and method, and an electronic device for mobile C-arms, so as to solve the problems existing in the prior art.

[0008] To achieve the above-mentioned technical objectives, according to a first aspect of the present invention, the present invention provides an image stitching system for a mobile C-arm, comprising: A lateral movement unit is disposed on the image chain assembly of the movable C-arm and is used to drive the image chain assembly to perform lateral linear movement. The image chain assembly includes an X-ray tube and a flat panel detector. The control unit is communicatively connected to the lateral movement unit and is used to control the lateral movement unit to move the image chain component to multiple target acquisition positions according to the movement planning path. The image processing unit is communicatively connected to the control unit and the flat panel detector, and is used to perform image acquisition at multiple target acquisition locations and to stitch the acquired sequence of images.

[0009] Specifically, the image stitching system further includes a distance detection device, which is installed on the X-ray tube and / or the flat panel detector, and is used to measure the distance from the target imaging area to the X-ray tube and / or the flat panel detector.

[0010] Specifically, the control unit includes an industrial computer; The industrial control computer includes an image stitching planning module and a position control module. The image stitching planning module is used to generate a movement planning path, and the position control module is used to generate control commands based on the movement planning path.

[0011] Specifically, the control unit includes a linear drive control module and a position feedback module; The linear drive control module is communicatively connected to the position control module. The linear drive control module is used to receive the control command and drive the lateral movement unit to move the image chain component to multiple target acquisition positions according to the movement planning path. The position feedback module is used to monitor and provide real-time position information of the image chain components.

[0012] Specifically, the image processing unit includes an image acquisition module, an image matching module, and an image stitching module; The image acquisition module is used to receive raw image data from the flat panel detector and perform preprocessing. The image matching module is used to determine the overlapping area of ​​adjacent images based on the image chain component movement position information provided by the control unit, and to calculate the translation relationship between images within the overlapping area using computer vision algorithms. The image stitching module is used to merge multiple images into a stitched panoramic image according to the translation relationship.

[0013] Specifically, the image stitching system also includes a display and interaction unit for displaying the stitched image and providing functions such as image scaling, panning, window width and window level adjustment, and saving in DICOM format.

[0014] According to a second aspect of the present invention, an image stitching method for a mobile C-arm is provided. Using the above-described image stitching system for a mobile C-arm, the image stitching method includes: S100: Receive a control command including the image stitching range, and plan multiple target acquisition positions and movement planning paths required for the image chain component of the mobile C-arm to perform sequential image acquisition according to the control command. S200: Control the lateral movement unit set on the mobile C-arm, drive the image chain assembly to move sequentially to each of the target acquisition positions according to the movement planning path, and perform image acquisition; S300. Perform feature matching and stitching processing on the acquired sequence images to generate the stitched image.

[0015] Specifically, the method for planning multiple target acquisition positions and movement planning paths required for the image chain assembly of the mobile C-arm to acquire sequential images includes: The distance from the target imaging area to the X-ray tube and / or the flat panel detector is measured by a distance detection device; The size of the flat panel detector is obtained, and the coverage area of ​​a single image acquisition is calculated based on the size of the flat panel detector, the distance from the X-ray tube to the flat panel detector, and the distance from the imaging part to the X-ray tube. Based on the coverage area of ​​the image acquisition, the start and end positions of the image acquisition are determined, and control instructions containing the image stitching range are generated according to the start and end positions. Based on the generated control instructions containing the image stitching range, multiple target acquisition positions and movement planning paths are automatically planned.

[0016] Specifically, the method for performing feature matching and stitching processing on the acquired sequence images to generate the stitched image includes: The system receives raw image data from the flat panel detector and performs preprocessing to obtain a preprocessed image sequence. In the image sequence, the overlapping region of adjacent images is determined, and the translation relationship between the images is calculated using computer vision algorithms within the overlapping region; Multiple images are merged into a stitched panoramic image based on the translation relationship.

[0017] Specifically, the step of fusing multiple images into a stitched panoramic image based on the translation relationship further includes: Image edge fusion processing is performed on the overlapping areas of image stitching to eliminate stitching marks.

[0018] According to a third aspect of the present invention, an electronic device is provided, comprising: a memory; and a processor, the memory storing computer-readable instructions which, when executed by the processor, implement the image stitching method for a mobile C-arm described above.

[0019] Beneficial effects: This invention provides an image stitching system and method for a mobile C-arm. By integrating a lateral movement unit into the image chain assembly of the C-arm and cooperating with the control unit and image processing unit, it achieves full automation and intelligence from device positioning and image acquisition to image stitching. It overcomes the traditional manual or whole-machine movement positioning methods. Driven by the built-in lateral movement unit, the image chain moves quickly, stably, and with precise position reproduction, greatly reducing operational difficulty and collision risks. It significantly improves the efficiency of intraoperative image acquisition, shortens surgical assistance time, and avoids invalid exposure through precise path planning, helping to reduce radiation doses for patients and medical staff. Furthermore, the integrated image processing can guide image matching based on known precise displacement information, greatly improving the speed and robustness of the stitching algorithm. Even with small overlapping areas, accurate and seamless stitching can be achieved, ultimately providing doctors with high-quality panoramic diagnostic images, significantly improving the accuracy and safety of surgery. Attached Figure Description

[0020] Figure 1 This is a flowchart of an image stitching method for a mobile C-arm provided in a specific embodiment of the present invention; Figure 2 This is a schematic diagram of the system composition of the image stitching system for a mobile C-arm provided in a specific embodiment of the present invention; Figure 3 This is a flowchart illustrating the implementation steps of image stitching provided in a specific embodiment of the present invention; Figure 4 This is a front view schematic diagram of the movable C-arm with a laterally movable image chain provided in a specific embodiment of the present invention. Figure 5 This is a top view of the movable C-arm with a laterally movable image chain provided in a specific embodiment of the present invention. Figure 6 This is a schematic diagram of the structure of the manual drive device provided in a specific embodiment of the present invention; Figure 7 This is a schematic diagram of one side structure of the motor drive device provided in a specific embodiment of the present invention; Figure 8 This is a schematic diagram of the other side of the motor drive device provided in a specific embodiment of the present invention; Figure 9 This is a top view of the structure of the lateral movement unit provided in a specific embodiment of the present invention, which is arranged in the flat panel detector. Figure 10 This is a front view schematic diagram of the lateral movement unit provided in a specific embodiment of the present invention, which is arranged in the flat panel detector. Figure 11This is a schematic diagram of the lateral movement unit provided in a specific embodiment of the present invention being installed when the flat panel detector is moving laterally. Figure 12 This is a graph showing the relationship between the dose rate and the lateral distance in the X-ray tube provided in a specific embodiment of the present invention. The above figures include the following reference numerals: 1. Translation mechanism; 3. C-arm body; 4. X-ray tube; 5. Flat panel detector; 6. Handle; 7. Gear shaft; 8. Rack; 9. Slider assembly; 10. Lateral base; 11. Linear guide rail; 12. Locking device; 13. Fixing plate; 14. Bushing; 15. Brake mounting plate; 16. Electromagnetic brake; 17. Bearing cover; 18. Motor; 19. Reducer; 20. Left limit switch; 21. Right limit switch; 22. Guide rail protective cover; 23. Gear and rack mechanism; 24. Linear guide rail pair; 25. Fixing bracket; 100. Lateral movement unit; 200. Control unit; 300. Image processing unit. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Other similar embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort should all fall within the scope of protection of this application. Furthermore, directional terms mentioned in the following embodiments, such as "up," "down," "left," and "right," are only for reference to the directions in the accompanying drawings; therefore, the directional terms used are for illustrative purposes and not for limiting the invention.

[0022] This invention addresses the problems of cumbersome operation, inaccurate positioning, low stitching efficiency, and high radiation dose associated with existing mobile C-arm imaging systems when acquiring large-area stitched images. It proposes an integrated, systematic solution. The invention primarily endows the C-arm imaging chain (X-ray tube and detector) with high-precision lateral linear movement capability. Based on this physical displacement information, a fully automated closed-loop system of planning, control, acquisition, and stitching is constructed. Precise and controllable displacement of the imaging chain is achieved through a mechanical lateral movement unit 100. Intelligent path planning and automatic control based on a geometric model are realized through a control algorithm. High-speed and robust image stitching utilizing prior displacement information is achieved. The synergistic effect of these three aspects ultimately achieves one-click operation and automatic image generation for clinical use.

[0023] The present invention will be further described below with reference to the accompanying drawings and preferred embodiments.

[0024] Example 1 Please see Figure 1This embodiment provides an image stitching system for a mobile C-arm, including a lateral movement unit 100, a control unit 200, and an image processing unit 300; The lateral movement unit 100 is mounted on the image chain assembly of the mobile C-arm and is used to drive the image chain assembly to perform lateral linear movement. The image chain assembly includes an X-ray tube and a flat panel detector. The control unit 200 is communicatively connected to the lateral movement unit 100 and is used to control the lateral movement unit 100 to move the image chain assembly to multiple target acquisition positions according to the movement planning path. The image processing unit 300 is communicatively connected to the control unit 200 and the flat panel detector and is used to perform image acquisition at multiple target acquisition positions and to stitch the acquired sequence of images.

[0025] It should be noted that, in this embodiment, see Figure 4 and Figure 5 The mobile C-arm includes a C-arm body 3 and an image chain assembly disposed on the C-arm body. The image chain assembly includes an X-ray tube 4 and a flat panel detector 5. The key improvement of this embodiment is the provision of a lateral movement unit 100.

[0026] In one specific embodiment, the lateral movement unit 100 is disposed below the translation mechanism 1 of the C-arm body, and is used to support and drive the entire imaging chain assembly, including the X-ray tube 4, the flat panel detector 5, and the original sliding, rotating, and translation mechanism 1, to perform lateral (i.e., linear movement along the long axis of the patient) linear motion. This achieves precise and stable translation of the entire imaging chain relative to the operating table, avoiding instability and positioning errors caused by pushing the entire device, and providing a stable and reliable mechanical foundation for subsequent sequential image acquisition.

[0027] Specifically, the lateral movement unit 100 includes a guiding mechanism, a transmission mechanism, a drive device, and a position feedback device. The guiding mechanism uses a high-precision linear guide rail 11 and a slider assembly 9 to ensure the straightness and stability of the motion trajectory of the image chain assembly during translation, which is a prerequisite for obtaining high-precision displacement information. The transmission mechanism uses a gear and rack mechanism 23 or a ball screw mechanism to convert the rotational motion output by the drive device into linear motion. The gear connects to the drive device, and the rack is fixed to the guide rail base. As a rotation-to-linear motion conversion mechanism, the transmission mechanism efficiently and accurately converts the rotational output of the drive device into the required linear motion.

[0028] In one specific embodiment, the guiding mechanism includes a linear guide rail 11 and a precisely fitted slider assembly 9, such as a slider with a ball bearing circulation structure. A transmission mechanism is mounted on the linear guide rail 11. The slider assembly 9 is fixedly connected to the transverse base 10 supporting the image chain assembly above. The linear guide rail 11 provides extremely high linear guiding accuracy and rigidity, effectively resisting lateral forces and torques, ensuring that the transverse base 10 and the entire image chain assembly above it can only move smoothly and with low friction along a preset linear trajectory. This is the basis for achieving high-precision displacement.

[0029] Furthermore, the transmission mechanism includes a rack and pinion mechanism or a ball screw mechanism to convert rotary motion into linear motion. Preferably, in this embodiment, a rack and pinion mechanism 23 is used as the transmission mechanism. The rack and pinion mechanism 23 is connected to the translation mechanism 1 of the C-arm body 3. The rack and pinion mechanism 23 includes a rack 8 and a gear. The rack 8 is fixedly installed along the direction of motion, and the gear is connected to the drive device. The transmission mechanism converts the rotary motion output by the drive device into linear motion. The rack and pinion transmission has the advantages of compact structure, high transmission efficiency, and good rigidity, and can reliably and accurately transmit the rotational power of the drive device into a linear force that drives the image chain assembly to translate.

[0030] Furthermore, this embodiment provides two optional driving modes: a manual driving device and a motor driving device, to adapt to different clinical needs and application scenarios. The manual driving device adopts a manual driving mode, and the motor driving device adopts a motor driving mode.

[0031] In some specific embodiments, see Figure 6 The manual drive mechanism includes a handle 6 as an operating lever, a gear shaft 7, and an optional locking device 12, such as... Figure 6As shown, handle 6 is located on the rear side of the transverse movement unit 100 for easy operator control. Handle 6 is connected to a gear via gear shaft 7. When the operator rotates handle 6, power is transmitted to the gear via gear shaft 7. One end of gear shaft 7 passes through bushing 14. The gear mounted on gear shaft 7 meshes with rack 8. Rack 8 is connected to translation mechanism 1. Gear shaft 7 can rotate around its own axis and drive translation mechanism 1 to move along linear guide rail 11. Gear shaft 7 is usually a hollow or solid shaft with bearings at both ends. The gear mounted on gear shaft 7 and rack 8 form a transmission pair. When gear shaft 7 rotates, it drives translation mechanism 1 to make linear motion through rack 8, and drives the entire slider assembly 9 and transverse base 10 to move linearly along linear guide rail 11 through fixed plate 13. That is, gear and rack mechanism 23 converts the rotational motion of handle 6 into linear translational motion of image chain assembly. The locking device 12 can be set on the transmission mechanism to mechanically lock the image chain assembly after it moves to the target position to prevent accidental displacement. The slider assembly 9 is connected to the translation mechanism 1, which moves together with the slider assembly 9. The linear guide rail 11 is fixed on the transverse base 10. The slider assembly 9 and the linear guide rail 11 together form the linear guide rail pair 24. The bushing 14 serves as a guide and support, and is usually a cylindrical metal sleeve. Its inner hole is interference-fitted or clearance-fitted with the gear shaft 7. The outside of the bushing 14 is connected to the brake mounting plate 15 to transmit braking torque. The electromagnetic brake 16 is mounted on the brake mounting plate 15 and is coaxially arranged with the bushing 14. When energized, it generates magnetic force, causing the brake pads to press against the bushing 14 to achieve rapid locking. When de-energized, it releases, allowing free rotation and preventing reverse sliding after the movement stops, ensuring positioning accuracy. The bearing cover 17 is mounted on the end of the gear shaft 7 to seal and fix the bearing. It is usually a press-fit metal cover to prevent lubricating oil leakage and foreign matter entry. The above solution provides a low-cost, highly reliable driving method that conforms to the operating habits of some doctors. Through mechanical force amplification, it makes moving heavy imaging chain components less strenuous, while the locking device 12 ensures the absolute stability of the equipment during exposure, thus guaranteeing image quality.

[0032] In some specific embodiments, see Figure 7 and Figure 8 The motor drive device includes a motor 18 and a reducer 19. The motor 18 can be either a servo motor 18 or a high-precision stepper motor 18. The servo motor 18 is connected to the gear shaft 7 via the reducer 19, which is connected between the motor output shaft and the transmission mechanism. When the drive motor 18 rotates forward or backward, it drives the gear after reduction and torque amplification, thereby realizing the automatic reciprocating lateral translation of the image chain assembly along the linear guide rail 11, achieving automated motion and high-precision closed-loop control.

[0033] like Figure 8As shown, the position feedback device in this embodiment is a position sensor mounted on the guide mechanism, such as limit switches at both ends of the travel of the linear guide 11. This position sensor is used to detect whether the image chain component has reached the limit position of lateral movement, thereby providing an important safety protection function to prevent mechanical collision damage caused by the equipment moving beyond its travel range due to misoperation or control failure, thus ensuring the safety of the equipment. In addition, in the motor 18 drive mode, an encoder can also be installed on the motor 18 to provide real-time feedback on the angle of the motor shaft, thereby calculating the linear position for more precise position control.

[0034] In a preferred embodiment, such as Figure 8 As shown, the position feedback device is located on the side of the linear guide rail 11, including three preset position points: the middle position and the maximum positions on both sides of the lateral movement. The middle position is usually used as the position during C-arm transportation and transfer. The other two position sensors are installed at both ends of the linear guide rail 11 to detect whether the image chain assembly has reached the limit position to prevent overtravel. The linear guide rail 11 is located above the transverse base 10. A left limit switch 20 and a right limit switch 21 are set at both ends of the linear guide rail 11, which are located at both ends of the movement path of the transverse base 10. When the transverse base 10 moves to the left or right limit position, its front end block triggers the corresponding limit switch and sends a signal to stop the motor 18 to prevent overtravel damage to the equipment. Motor 18 is mounted on transverse base 10, and its output end is connected to gear shaft 7. Gear shaft 7 meshes with rack 8 fixed on linear guide rail 11. Transverse base 10 and linear guide rail 11 form linear guide pair 24 through slider assembly 9. Driven by motor 18, it performs reciprocating linear motion along the guide rail. Left limit switch 20 and right limit switch 21 are located at the beginning and end of the stroke of transverse base 10, respectively, to detect the extreme positions of movement and provide feedback control signals. The components are connected by bolts, keys, or interference fits, resulting in a compact structure and reliable assembly. In use, to automatically achieve C-arm image stitching, the system moves the transverse movement unit 100 from one side of linear guide rail 11 to the other. The two preset extreme position points serve as the start and end points of the transverse movement during image stitching.

[0035] It should be noted that the working process of the movable C-arm with a laterally movable image chain in this embodiment includes: when lateral movement is required, if manual mode is used, the operator can rotate handle 6 to move the image chain component smoothly; if automatic mode is used, the control system commands motor 18 to rotate, driving the image chain to accurately reach the specified coordinates. After reaching the target position, it can be manually or automatically locked and fixed, and then exposure and filming are performed.

[0036] It should be noted that the lateral movement unit of the aforementioned movable C-arm of the imaging chain is located below the translation mechanism of the C-arm body. It provides controllable lateral linear motion for the imaging chain components, supports and drives the entire imaging chain components, including the translation mechanism, X-ray tube, and flat panel detector, to perform lateral linear motion. This achieves synchronous and linear motion of the imaging chain components as a rigid whole, thus strictly maintaining the inherent projection geometry during the sequential image acquisition process. It solves the problem of inconsistent imaging geometry caused by relative displacement of components or shaking of the whole machine in traditional movement methods, ensuring the accuracy and repeatability of spatial relationships between multiple images. It is particularly suitable for clinical scenarios with extremely high requirements for imaging geometry consistency, and provides reliable mechanical protection for obtaining high-quality, quantifiable medical image sequences.

[0037] In the second preferred embodiment, such as Figures 9-11 As shown, another lighter image chain with a laterally movable C-arm is provided. The core difference between this embodiment and the above embodiment is that the lateral movement unit 100 in this embodiment does not support the entire image chain, but is only set at one end where the flat panel detector 5 is located, and is used to drive the flat panel detector 5 to move laterally independently, as shown. Figure 11 As shown, the position of the X-ray tube 4 remains fixed during the movement, while only the flat panel detector 5 moves laterally.

[0038] The lateral movement unit 100 in this embodiment also includes a guiding mechanism, a transmission mechanism, and a driving device. The guiding mechanism includes a linear guide rail 11 and a slider assembly 9, wherein, as shown... Figure 9 As shown, a guide rail protective cover 22 is also provided on the linear guide rail 11. Its function is to prevent external dust and other impurities from entering the interior of the guide rail, avoiding impurities from hindering or causing wear on the relative movement between the linear guide rail 11 and the slider assembly 9, thereby ensuring the smoothness and accuracy stability of the guide mechanism's movement and extending the service life of the equipment. The transmission mechanism is preferably a gear and rack mechanism 23. In this embodiment, the lateral movement unit 100 is mounted on the support arm of the flat panel detector 5 through a fixed bracket 25. The gear is driven by a drive device and meshes with the fixed rack 8, thereby driving the slider assembly 9 and the flat panel detector 5 connected to it to slide laterally along the linear guide rail 11.

[0039] like Figure 10As shown, the C-arm body 3 serves as the main support structure, and its front end is reinforced with a support structure set on the C-arm. The guide rail fixing plate 13 is fixed inside the C-arm to support the linear guide rail pair 24. The slider assembly 9 of the linear guide rail pair 24 is connected to the fixed bracket 25 to form a motion transmission chain. The flat plate detector 5 is installed on the fixed bracket 25 and moves synchronously with it. The motor 18 is installed inside the C-arm, and its output shaft is connected to the gear. The gear meshes with the rack 8 fixed inside the C-arm. When the motor 18 starts, it drives the slider assembly 9 to move along the linear guide rail pair 24 through the gear and rack mechanism 23, thereby driving the flat plate detector 5 to make precise displacement in the horizontal direction. The left limit switch 20 and the right limit switch 21 are set at both ends of the motion path to limit the stroke range and prevent overload damage.

[0040] It should be noted that in traditional techniques, to maintain the projection geometry, the X-ray tube 4 and the flat panel detector 5 should move synchronously. However, experimental verification has shown that at typical working distances of a moving C-arm (e.g., SID of 100-120 cm), the dose attenuation of the X-ray beam in the lateral direction (long axis) is much lower than the attenuation in the heel effect direction (cathode-anode direction). Data shows that within a lateral offset of ±30 cm, the dose attenuation rate is typically less than 10% and relatively uniformly distributed. This level of uniform attenuation can be effectively corrected by image processing algorithms. Therefore, although moving only the detector changes the projection centerline, it has little impact on the final image quality, especially on the effectiveness of image stitching algorithms based on grayscale features. This structural design greatly simplifies the mechanical structure, reduces the weight and inertia of moving parts, reduces the impact on the overall balance system of the C-arm, and significantly reduces manufacturing costs. This solution provides an optimized implementation that balances performance and cost, and is particularly suitable for cost-sensitive clinical applications where absolute geometric fidelity requirements are acceptable.

[0041] It should be noted that in the above embodiment, the image chain can move laterally in a movable C-arm. The lateral movement unit does not support the entire image chain, but is only set at one end where the flat panel detector 5 is located. It is used to drive the flat panel detector to move laterally independently, while the position of the X-ray tube remains fixed during the movement. This significantly reduces the mechanical complexity and cost of the system. The weight and inertia of the moving parts are greatly reduced, which reduces the impact on the overall balance of the C-arm. This makes the structure lighter and the manufacturing cost lower. While maintaining sufficient imaging quality, it achieves a balance between structural simplification, cost optimization and ease of operation.

[0042] In a third preferred embodiment, a third structural configuration is provided for a laterally movable C-arm of the imaging chain, wherein the lateral movement unit 100 includes two independent sub-units: a detector-end lateral movement unit 100 and an X-ray tube-end lateral movement unit 100. The detector-end lateral movement unit 100 is disposed at the support end of the flat panel detector 5, and the X-ray tube-end lateral movement unit 100 is disposed at the support end of the X-ray tube 4, for driving the two to perform independent lateral movements respectively.

[0043] In this embodiment, both the detector end lateral movement unit 100 and the X-ray tube end lateral movement unit 100 have the same complete structure as in Embodiment 1, including their respective guide mechanism, transmission mechanism and drive device. The structure of these two sub-units can be symmetrical or designed according to spatial constraints. In this embodiment, the drive device is preferably a motor 18 drive device, including a servo motor 18 or a stepper motor 18 and a matching reducer 19. The specific connection method is the same as in Embodiment 1.

[0044] The structural configuration of this embodiment is characterized by two lateral movement subunits respectively located at the X-ray tube end and the detector end, providing independent lateral movement degrees of freedom for the two core components of the imaging chain assembly. Through this structural design, the X-ray tube 4 and the flat panel detector 5 can perform lateral movement as needed. When the two subunits are driven in a coordinated manner, their structure itself supports relative or synchronous movement between the X-ray tube 4 and the flat panel detector 5. This dual independent drive structure provides the hardware foundation for maintaining a precise alignment between the focal point of the X-ray tube 4 and the center of the detector during lateral movement. Therefore, the mechanical structure design of this embodiment provides the physical conditions for maintaining stable projection geometry during lateral scanning. This helps to reduce geometric differences between sequential images caused by changes in projection angle from the source, thus providing an ideal hardware platform for acquiring high-quality image sequences, especially for subsequent processing where image geometric consistency is extremely important. This structural configuration is particularly suitable for complex clinical surgical or scientific research applications with extremely high imaging quality requirements.

[0045] It is understood that this embodiment provides a mobile C-arm with a laterally movable imaging chain, wherein the lateral movement unit 100 includes two independent sub-units: a detector-end lateral movement unit and an X-ray tube-end lateral movement unit. The detector-end lateral movement unit 100 is disposed at the support end of the flat panel detector 5, and the X-ray tube-end lateral movement unit 100 is disposed at the support end of the X-ray tube 4, for driving the two to move independently. By configuring independent lateral movement units 100 for the X-ray tube 4 and the flat panel detector 5 respectively, independent movement of the two is allowed, providing greater operational flexibility.

[0046] The core of this embodiment lies in synchronous control. Since the X-ray tube and the flat panel detector are two independent moving parts, maintaining the necessary relative spatial geometry for imaging, such as center alignment, requires high-precision synchronous control of the two drive devices of the detector-end lateral movement unit and the X-ray tube-end lateral movement unit. This is typically achieved by the upper-level control system comparing the position feedback signals of both (such as encoder feedback) and adjusting the motor speed in real time. This structural design allows the X-ray tube and the flat panel detector to move independently when necessary. More importantly, when synchronous lateral scanning is required, the geometric relationship between the X-ray tube focal point, the detector center, and the imaging area center remains constant. This completely eliminates geometric distortion caused by changes in relative position, resulting in the highest quality and most consistent image sequence. This provides a more ideal data source for subsequent image stitching, making it particularly suitable for complex clinical surgeries with high image quality requirements. By configuring independent lateral movement units for the X-ray tube and the flat panel detector, independent movement is allowed, providing greater operational flexibility.

[0047] In summary, the above-described three implementations with different focuses—whether it's a stable platform supporting overall movement, a lightweight design that only moves the detector, or a high-precision solution where both move separately—all achieve the core mechanical architecture of guidance, transmission, drive, and position feedback. This effectively solves the fundamental problems of lateral movement accuracy and stability of the mobile C-arm and lays the foundation for its functional and intelligent expansion.

[0048] Furthermore, in this embodiment, the control unit includes an industrial computer, which includes an image stitching planning module and a position control module. The image stitching planning module is used to generate a movement planning path, and the position control module is used to generate control commands based on the movement planning path.

[0049] Furthermore, the control unit includes a linear drive control module and a position feedback module. The linear drive control module is communicatively connected to the position control module. The linear drive control module is used to receive control commands and drive the lateral movement unit to move the image chain components to multiple target acquisition positions according to the movement planning path. The position feedback module is used to monitor and provide feedback on the position information of the image chain components in real time.

[0050] It is understood that the industrial control computer in the control unit of this embodiment includes multiple functional modules such as an image stitching planning module, a position control module, and a linear transmission control module.

[0051] Specifically, the image stitching planning module allows users to input or select the start and end points of the stitching in the software interface. Its core algorithm automatically calculates the coverage area of ​​a single projection based on the flat panel detector size (DetLength), the distance from the imaging part to the X-ray tube (STD) measured by the distance detection device, and the distance from the X-ray tube to the flat panel detector (SDD) known to the system, using the principle of similar triangles. S = DetLength STD / SDD; Where S represents the coverage area of ​​a single projection of the C-arm imaging chain assembly, DetLength represents the size of the flat panel detector, STD represents the distance from the imaging part to the X-ray tube, and SDD represents the distance from the X-ray tube to the flat panel detector. Subsequently, the image stitching planning module automatically calculates the optimal number of acquisitions N and the precise coordinates of N target acquisition positions based on the total stitching length and the preset minimum image overlap ratio, forming a complete motion planning path. According to this technical solution, complex clinical needs, such as determining the length range of the bone to be imaged, are transformed into a series of precise, executable, and radiation-optimized mechanical instructions. This replaces doctors' experience-based estimations and manual trial and error, which is key to reducing radiation dose and improving operational efficiency.

[0052] Furthermore, the position control module receives the path information output by the image stitching planning module and converts it into specific motion control commands. The linear drive control module, typically implemented with a motion controller and driver, receives commands from the position control module and drives the motor (or prompts for manual operation), while simultaneously receiving signals from the position feedback module (such as an encoder or limit switch). This forms a high-precision position servo closed loop, ensuring that the image chain components can accurately and reliably move to each preset target acquisition position, a key control process for achieving automation.

[0053] In this embodiment, the image processing unit includes an image acquisition module, an image matching module, and an image stitching module. The image acquisition module receives raw image data from the flat panel detector and performs preprocessing. The image matching module determines the overlapping area of ​​adjacent images based on the image chain component movement position information provided by the control unit, and calculates the translation relationship between images within the overlapping area using computer vision algorithms. The image stitching module fuses multiple images into a stitched panoramic image according to the translation relationship.

[0054] Specifically, the image stitching system in this embodiment also includes a display and interaction unit for displaying the stitched image and providing functions such as image scaling, panning, window width and window level adjustment, and saving in DICOM format.

[0055] Understandably, the image processing unit also runs on an industrial control computer or a separate processing device. The image acquisition module communicates with the flat panel detector. After receiving the arrival and acquisition signal from the control unit, it automatically triggers X-ray tube exposure and acquires the raw DICOM image data for preprocessing such as noise reduction and contrast enhancement. Traditional stitching algorithms require time-consuming feature searches across the entire image. However, in this embodiment, the control unit can provide precise displacement information (such as the movement distance D) between adjacent acquisition positions of the image chain components. Therefore, the image matching module can pre-calculate the approximate overlap area between two adjacent images. The algorithm only needs to run the matching algorithm (such as NCC or SSD template matching) within this overlap area (e.g., expanding a small search window centered on the estimated position). This technical solution transforms the global search in traditional stitching algorithms into a localized, fine-grained matching with a clearly defined search target, greatly improving matching speed, success rate, and accuracy. It is particularly adept at handling medical images with small overlap areas and indistinct texture features.

[0056] Furthermore, the image stitching module aligns multiple images based on the precise translation relationship between the images calculated by the image matching module, and performs fusion processing (such as fade-in / fade-out fusion) to eliminate seams and form a seamless panoramic image.

[0057] In some specific embodiments, the image stitching system for mobile C-arms described above also includes a display and interaction unit: displaying the stitched panoramic image on a high-resolution medical monitor, allowing doctors to perform operations such as zooming, panning, and adjusting window width and level, and saving it in standard DICOM format for archiving. This constitutes a complete closed loop for clinical applications.

[0058] It should be further explained that the workflow of the image stitching system for the mobile C-arm in this embodiment includes: after the user sets the stitching range, the system begins to automatically move along the planned path, sequentially acquire images, automatically stitch them together, and display the results. Throughout the process, in motor-driven mode, movement and acquisition are completely automatic; in manual mode, the system guides the operator to the designated position via graphical and audio interfaces, and automatically exposes the image upon reaching the designated position. By adopting the above technical solution, the previously complex operation requiring multiple manual interventions and high technical skills is simplified into a smooth automated process, significantly improving the efficiency and image consistency in the operating room.

[0059] In a preferred embodiment, another implementation method is provided, the main difference from the first embodiment being that: the lateral movement unit is only provided at one end where the flat panel detector is located, and is used to drive the flat panel detector to move laterally independently, while the position of the X-ray tube remains fixed during the splicing process.

[0060] The control system and image processing flow in this embodiment are similar to those in Embodiment 1, but the control unit only plans and controls the movement path of the flat panel detector. Because the X-ray tube is fixed, the centerline of the X-ray beam will change during lateral movement, such as... Figure 12 As shown, research and experiments have revealed that, at the commonly used imaging distance of mobile C-arms, the dose attenuation of the X-ray tube within a lateral range of ±30cm is relatively uniform and the attenuation rate is usually less than 10%. This attenuation can be corrected for uniformity through image processing, and its impact on the final image stitching quality is within an acceptable range.

[0061] It is understandable that the mechanical structure of the lateral movement unit used in this embodiment is lighter, has less impact on the original balance system of the C-arm, and has lower manufacturing costs. At the same time, it can still provide the core automatic splicing capability based on precise displacement information, providing an important optimization option for system design.

[0062] In a preferred embodiment, a third implementation is provided, wherein the aforementioned lateral movement unit comprises two sub-units: a lateral movement unit at the flat panel detector end and a lateral movement unit at the X-ray tube end, respectively used to drive the flat panel detector and the X-ray tube to perform independent lateral movements. In this embodiment, the driving device is preferably motor-driven. The control unit needs to synchronously control the two motors to ensure that the relative geometric relationship (such as center alignment) between the X-ray tube and the flat panel detector remains unchanged during movement, thereby maintaining the consistency of the projection geometry. It is understood that while achieving large-scale lateral coverage of the imaging chain, it can effectively maintain the constancy of the projection geometry, obtain the highest quality sequence images, and provide the most ideal source data for subsequent stitching, making it particularly suitable for advanced clinical or research applications with extremely strict requirements for image geometric distortion.

[0063] It should be noted that this embodiment provides an image stitching system for a mobile C-arm, including a lateral movement unit 100, a control unit 200, and an image processing unit 300. By integrating the lateral movement unit onto the image chain assembly of the C-arm and having it work collaboratively with the control unit and image processing unit, the system achieves full automation and intelligence from device positioning and image acquisition to image stitching. This overcomes the traditional manual or whole-machine movement positioning methods. Driven by the built-in lateral movement unit, the image chain moves quickly, stably, and with precise position reproduction, greatly reducing operational difficulty and collision risks. It significantly improves the efficiency of intraoperative image acquisition, shortens surgical assistance time, and avoids invalid exposure through precise path planning, helping to reduce radiation doses to patients and medical staff. Furthermore, the integrated image processing can guide image matching based on known precise displacement information, greatly improving the speed and robustness of the stitching algorithm. Even with small overlapping areas, accurate and seamless stitching can be achieved, ultimately providing doctors with high-quality panoramic diagnostic images and significantly improving the accuracy and safety of surgery.

[0064] Example 2 Please see Figure 2 This embodiment provides an image stitching method for a mobile C-arm, employing the image stitching system for a mobile C-arm described in Embodiment 1 above. The image stitching method includes: receiving a control command containing an image stitching range; planning multiple target acquisition positions and movement planning paths required for the image chain component of the mobile C-arm to acquire sequential images according to the control command; controlling a lateral movement unit disposed on the mobile C-arm to drive the image chain component to move sequentially to each of the target acquisition positions according to the movement planning path and perform image acquisition; and performing feature matching and stitching processing on the acquired sequential images to generate a stitched image.

[0065] Understandably, this embodiment achieves a fully automated image stitching process by deeply integrating high-precision mechanical translation, intelligent path planning, and optimized image algorithms. It solves the pain points of inaccurate positioning and cumbersome operation associated with existing manual or whole-machine movement methods. Through precise linear drive and closed-loop control of the lateral movement unit, it ensures high accuracy and repeatability of the sequence image acquisition position, providing high-quality source data with consistent geometric relationships for stitching. This significantly improves the efficiency and reliability of image stitching. Utilizing known precise displacement information as prior knowledge greatly narrows the search range of the image matching algorithm, enabling fast and accurate matching and stitching even in areas with small image overlap. This overcomes the problems of high computational load and easy matching failures in traditional algorithms. One-click automated operation replaces repeated manual positioning and trial exposures, significantly shortening image acquisition time during surgery and improving surgical efficiency. Furthermore, precise path planning avoids unnecessary exposures, helping to optimize radiation protection and reduce the cumulative radiation dose to patients and medical staff.

[0066] See Figure 2 The specific implementation method of the image stitching method for the mobile C-arm in this embodiment is as follows: S100: Receive a control command including the image stitching range, and plan multiple target acquisition positions and movement planning paths required for the image chain component of the mobile C-arm to perform sequential image acquisition according to the control command. In this embodiment, the method for planning multiple target acquisition positions and movement planning paths required for the image chain assembly of the mobile C-arm to acquire sequential images includes: The distance from the target imaging area to the X-ray tube and / or the flat panel detector is measured using a distance detection device; the size of the flat panel detector and the distance from the X-ray tube to the flat panel detector are obtained; the coverage area of ​​a single image acquisition is calculated based on the distance from the flat panel imaging area to the X-ray tube; the start and end positions of the image acquisition are determined based on the coverage area of ​​the image acquisition; and control instructions containing the image stitching range are generated based on the start and end positions; multiple target acquisition positions and movement planning paths are automatically planned based on the generated control instructions containing the image stitching range.

[0067] It should be noted that the above steps are the key starting point for achieving automation and intelligence in the image stitching method of this embodiment. The main function of the above steps is to transform the user's abstract clinical needs, such as how many lengths of bones to photograph, into a sequence of mechanical movements that the device can precisely execute. The specific implementation steps are as follows: (1) Distance measurement and geometric parameter acquisition: First, a distance detection device (such as a laser rangefinder) integrated near the X-ray tube and / or flat panel detector is used to non-contactly measure the straight-line distance from the device to the target imaging site, such as the patient's body surface or a preset anatomical landmark, i.e., the distance STD from the imaging site to the X-ray tube. At the same time, the system calls known fixed parameters from memory or configuration files: the effective size (DetLength) of the flat panel detector and the distance (SDD) from the X-ray tube focal point to the flat panel detector imaging surface. For three-dimensional image stitching, the distance (SOD) from the X-ray tube to the rotational isocenter of the target imaging site needs to be obtained or calculated. These parameters together define the imaging geometry model of a single projection. (2) Precise calculation of the coverage area of ​​a single image: Based on the above parameters, the actual area (S) within the patient's body that can be covered in a single acquisition is automatically calculated using the principle of similar triangles in fluoroscopic imaging. The specific calculation formula is as follows: For 2D stitching, the coverage area of ​​a single image acquisition is determined by the distance STD from the illuminated object to the X-ray tube, i.e.: S = DetLength × (STD / SDD); For 3D stitching, the coverage area of ​​a single image acquisition is determined by the distance SOD from the isocenter of rotation of the illuminated object to the X-ray tube, i.e.: S = DetLength × (SOD / SDD); The flat panel detector size DetLength and its coverage area S at the patient level form a similar triangle relationship. The scaling factor is determined by the ray path, i.e., the ratio of STD (or SOD) to SDD. This calculation transforms the physical size of the flat panel detector into the effective field of view size at the anatomical level of interest, which is the basis for all subsequent planning.

[0068] (3) Intelligent path planning and location generation: Users can specify the start (P_start) and end (P_end) positions for stitching via the human-machine interface, which defines the total anatomical length to be imaged (L_total = |P_end - P_start|). Upon receiving this instruction, the system automatically plans the stitching according to the following logic: 1) Calculate the minimum number of acquisitions (N): Under the premise of meeting the clinical and algorithmic requirement that adjacent images must have a minimum overlap ratio (e.g., 15%-20%), the system calculates the minimum number of image acquisitions N required for the total coverage length L_total based on the coverage area S. The principle is to minimize the number of acquisitions as much as possible to reduce radiation dose and shorten the time while ensuring the success rate of stitching. 2) Determine the acquisition location of each target: Starting from P_start, calculate the precise coordinates (Pos_1, Pos_2, ..., Pos_N) of N target acquisition points in sequence based on the calculated S and the preset overlap amount. Among them, Pos_N coincides with P_end or meets the coverage requirements. These location points constitute a discrete acquisition task sequence.

[0069] 3) Generate a movement planning path: The system connects these discrete location points in sequence to form a complete movement planning path from Pos_1 to Pos_N. For motor-driven mode, this path can be directly converted into the motor's motion curve; for manual mode, this path will be used to generate visual guidance information on the display.

[0070] According to the above technical solution, the traditional experience-based and vague manual positioning process is transformed into a quantitative automatic calculation process based on a precise geometric model. This ensures that the target of each movement is clear and the displacement is accurate. Moreover, the entire acquisition sequence meets the basic requirements of image stitching algorithm for image overlap during the planning stage. At the same time, by pursuing the fewest acquisitions, it reflects the principle of reasonable, feasible and minimal radiation protection. The calculation process is completed in real time by the image stitching planning module on the industrial control computer. The user interface clearly displays the planned path and position points, which significantly improves the ease of use, accuracy and security of the invention.

[0071] S200: Control the lateral movement unit set on the mobile C-arm, drive the image chain assembly to move sequentially to each of the target acquisition positions according to the movement planning path, and perform image acquisition; It should be noted that the above steps translate the planned path into the actual physical movement of the image chain components, triggering image acquisition at precise locations to obtain high-quality image sequences. The specific implementation steps are as follows: (1) Issue control commands for path movement: The position control module and linear drive control module in the control unit receive movement planning path instructions from the image stitching planning module. These instructions typically contain an ordered sequence of target positions [Pos_1, Pos_2, ..., Pos_N]. The system then initiates the corresponding control logic based on the drive mode configured for the lateral movement unit. 1) Motor drive mode: For embodiments using servo / stepper motors, the system converts the target position sequence into motor motion commands (such as pulse sequences or analog signals), sends them to the motor through the driver, and the position feedback device, such as a motor encoder or linear encoder, feeds back the actual position of the image chain to the controller in real time, forming a closed-loop control system. The controller continuously compares the target position with the actual position and dynamically adjusts the motor output until the error between the actual position and the target position is less than a preset threshold, such as ±0.5mm. At this point, the system determines that the target acquisition position has been reached, achieving accurate and automatic positioning without human intervention.

[0072] 2) Manual Drive Mode: For embodiments using a manual crank, the system does not directly output power commands. The control unit provides clear guidance information to the operator through a human-machine interface (such as a touch screen or indicator lights). For example, the screen graphically displays the current target position (Pos_k), the current position, and the direction and distance of the deviation between the two. The operator manually turns the crank according to the guidance. The position feedback device installed on the guide rail, such as a potentiometer or incremental encoder, monitors the movement distance in real time and feeds back the current position to the system. When it is determined that the current position has entered the target position tolerance range, the interface will give a clear visual and / or audible prompt (such as "In position, please stop"). The operator then stops the operation and can manually lock the mechanism. This mode retains the operator's direct control while ensuring accuracy.

[0073] (2) Target acquisition location acquisition: When the system (in automatic mode) or the operator (after receiving a prompt in manual mode) confirms that the image chain components have stably reached a target acquisition position Pos_k, the control unit immediately and automatically executes the triggered exposure. That is, the control unit sends a command to the high-voltage generator to trigger the X-ray tube to perform instantaneous exposure at the preset exposure parameters. At the same time, the control unit sends an acquisition command to the flat panel detector. The flat panel detector receives the X-ray signal after penetrating the patient and converts it into digital image data. The acquired image data is automatically assigned an identifier and associated with metadata such as the current acquisition position Pos_k, exposure parameters, and patient information. It is then packaged and stored (usually in DICOM format) to provide complete information for subsequent processing.

[0074] (3) Looping acquisition of image sequences: After completing the acquisition at position Pos_k, the system automatically enters the next cycle: the control unit drives the image chain component to the next target position Pos_{k+1}, repeating the above process of moving-position confirmation-trigger acquisition. This cycle continues until image acquisition is completed at all N positions in the path sequence. Throughout the process, the current acquisition sequence number, remaining position, device status and other system statuses are displayed in real time, providing complete process visibility.

[0075] Understandably, by adopting the above technical solution, a reliable and accurate mapping from the planned path to the physical action is achieved, ensuring the efficiency and standardization of the sequence image acquisition process, avoiding the uncertainty and delay of manual operation in the traditional method, and providing a solid guarantee for generating image sequences with strict and consistent geometric relationships that are easy to stitch together, making the entire technical solution highly feasible and repeatable.

[0076] S300. Perform feature matching and stitching processing on the acquired sequence images to generate the stitched image, as follows: The flat panel detector receives the acquired raw image data and performs preprocessing, including noise removal, contrast enhancement, and geometric correction, to obtain a preprocessed image sequence. In the image sequence, the overlapping region of adjacent images is determined, and the translation relationship between the images is calculated using computer vision algorithms within the overlapping region; Multiple images are merged into a stitched panoramic image based on the translation relationship.

[0077] Furthermore, the step of fusing multiple images into a stitched panoramic image based on the translation relationship also includes: Image edge fusion processing is performed on the overlapping areas of image stitching to eliminate stitching marks.

[0078] It should be noted that the above steps fully utilize the image chain mechanical displacement information obtained in step S200 to guide, accelerate, and optimize the entire image matching and stitching process, thereby achieving fast, accurate, and robust panoramic image generation. The specific implementation steps are as follows: (1) Image preprocessing and serialization: First, the image acquisition module receives the raw image data stream from the flat panel detector and performs standardized preprocessing, including: Noise reduction: Algorithms that filter out X-ray quantum noise and electronic noise to improve the image signal-to-noise ratio; Contrast enhancement: Gray-scale stretching or histogram equalization is performed based on the characteristics of medical images to make target structures such as bones clearer; Geometric correction: Corrects the inherent pixel distortion or response non-uniformity of the flat panel detector to ensure image geometric accuracy.

[0079] After preprocessing, the images are organized into a sequence image set {I_1, I_2, ..., I_N} according to the acquisition order, and are strictly correlated with the acquisition position coordinates {Pos_1, Pos_2, ..., Pos_N} corresponding to each image recorded by the control unit.

[0080] (2) Determine the overlapping region and initialize the matching using prior information: For two adjacent images I_k and I_{k+1} in the sequence, the estimated overlap region is first calculated. This is achieved by inversely deriving the theoretical overlap range of the two images at the patient's anatomical level based on the known, precise mechanical displacement ΔD = Pos_{k+1} - Pos_k (from the position feedback device) and the system's imaging geometry model (such as SDD and STD). Subsequently, through perspective projection, this overlap range at the anatomical level is mapped back to the pixel coordinate system of the two images, delineating the estimated overlap regions R_k and R_{k+1} on I_k and I_{k+1} respectively. This significantly reduces computational load, improves matching speed, and substantially reduces the risk of mismatches caused by complex structures in non-overlapping areas of the images (such as surgical instruments or background).

[0081] (3) Perform fine matching within the estimated overlap region: Within the defined R_k and R_{k+1} regions, the image matching module performs a high-precision registration algorithm. A preferred implementation method is to use template matching. 1) Template extraction: Extract a sub-image patch with rich texture features from the center of the estimated overlapping region R_k of image I_k as template T; 2) Search and Matching: The template T is slid two-dimensionally within the corresponding estimated overlap region R_{k+1} of image I_{k+1}. For each sliding position, the similarity between the template and the covered region is calculated. Commonly used similarity metrics include: Normalized cross-correlation (NCC): Robust to changes in illumination; Sum of Squared Errors (SSD): High computational efficiency; Calculate the translation relationship: Find the position that maximizes or minimizes the similarity metric (NCC) and minimizes it (SSD). The offset (Δx, Δy) of this position relative to the initial position is the precise translation relationship between the two images at the pixel level. This relationship is verified against the known mechanical displacement ΔD. If the deviation is within the allowable error, it is accepted; otherwise, a warning may be triggered or a more complex algorithm may be used.

[0082] (4) Image fusion and seamless stitching: After obtaining the precise translation relationships between all adjacent image pairs, the image stitching module performs the following: 1) Global coordinate alignment: Using the coordinate system of the first image I_1 as the reference, calculate the position of all subsequent images I_k in the reference coordinate system by accumulating the coordinates.

[0083] 2) Image fusion: All images are resampled and aligned according to their global coordinates. In overlapping areas, a gradient fusion algorithm (such as linear weighted fusion) is used to make the grayscale transition at the seam natural and smooth, eliminating splicing marks.

[0084] 3) Output Generation: Generates a seamless, wide-field-of-view 2D panoramic image. For 3D image sequences (such as multiple 3D volume data reconstructed from 2D projected images acquired from different angles), the stitching principle is similar, but the data objects are voxels, and matching and fusion are performed in 3D space. The stitched image is displayed on the system's monitor in real time. Doctors can observe each part of the stitched image in detail by zooming, panning, and adjusting the window width and level, thereby making accurate diagnoses. In addition, the system also supports saving the stitched image in DICOM format for easy archiving and subsequent review.

[0085] Understandably, the above technical solution effectively solves the technical problems of long computation time, high requirements for image overlap, and easy failure in low contrast or structured backgrounds in traditional medical image stitching by guiding image matching with mechanical prior information. It ensures the efficiency, accuracy and robustness of the stitching process and can provide clinicians with high-quality, wide-range panoramic diagnostic images.

[0086] See Figure 3 The working principle of this invention will be illustrated below with specific examples: Step 1: Initial Preparation Phase (1) After the mobile C-arm system is started, it first performs an initial pose self-check: to determine whether the C-arm is in the preset positive initial position and whether the mechanical structure posture meets the imaging reference requirements: If the self-test result is negative, the system will automatically drive the mechanical motion components of the C-arm to move and calibrate to the preset positive initial position. If the self-test result is positive, it will proceed directly to the next step.

[0087] (2) Confirmation of the effectiveness of the optical positioning device The system detects whether the projected light spot of the optical positioning device falls within the effective field of view of the C-arm fluoroscopic imaging. If the detection result is negative, the system automatically or manually adjusts the installation position and angle of the optical positioning device until its projection area completely covers the effective field of view of the fluoroscopic imaging. If the detection result is positive, the system proceeds to the next step.

[0088] (3) Imaging exposure parameter configuration Based on clinical imaging needs (such as target area, tissue thickness, etc.), the user or system automatically adjusts and confirms the X-ray exposure parameters, including but not limited to tube voltage, tube current, exposure time, etc., to ensure that the subsequently acquired images have the clarity and contrast required for clinical diagnosis.

[0089] (4) Collision safety inspection The system initiates a collision detection program, using sensors to monitor the relative position of the C-arm to the surrounding environment and the patient in real time to determine if there is a collision risk. If the detection result is negative (i.e., there is a collision risk), the system will automatically drive the C-arm to adjust its spatial pose until the collision detection is successful. If the test result is satisfactory, proceed to the next step.

[0090] Step 2: Image stitching execution stage (1) Image stitching function triggered Users select the horizontal image stitching function through the system operation interface and confirm the start. Then, they step on the foot switch to trigger the system to enter the automatic stitching execution process.

[0091] (2) First image acquisition and quality verification The system automatically triggers X-ray exposure at the initial positive position (referred to as position 1) to acquire the first fluoroscopic image. After acquisition, the system displays the image in real time on the operation interface, allowing the user to judge whether the image quality meets clinical requirements (including but not limited to image clarity, field of view integrity, and absence of artifacts). If the user judges that the image quality does not meet the requirements, the foot switch is released, and the system terminates the current stitching process. If the user judges that the image quality meets the requirements, the foot switch remains pressed, and the system proceeds to the next step.

[0092] (3) Automatic movement of the image chain and acquisition of the second image With the user keeping the foot switch pressed, the system drives the image chain to move automatically along the preset trajectory to the second position (referred to as position 2), and automatically triggers X-ray exposure upon reaching the position to acquire a second fluoroscopic image. During the movement, the system provides real-time feedback on the position status of the image chain.

[0093] (4) Quality verification of the second image The system displays the second image acquired at location 2 in real time on the operation interface, allowing the user to judge whether the image quality meets clinical requirements: if the user judges that it does not meet the requirements, the user releases the foot pedal switch, and the system terminates the current stitching process; if the user judges that it meets the requirements, the system proceeds to the next step.

[0094] Step 3: Image Synthesis and Output Stage The system invokes a preset image registration and fusion algorithm to perform feature matching, spatial registration, and pixel fusion processing on the two images acquired at the first and second locations, generating a complete large-field-of-view stitched image. The stitched image will be displayed on the user interface and can be stored in the system database or exported for clinical diagnostic use.

[0095] It should be noted that this embodiment provides an image stitching method for a mobile C-arm. By integrating the lateral movement unit into the image chain assembly of the C-arm and working in conjunction with the control unit and image processing unit, the entire process from device positioning and image acquisition to image stitching is automated and intelligent. This overcomes the limitations of traditional manual or whole-machine movement positioning methods. Driven by the built-in lateral movement unit, the image chain moves quickly, stably, and with precise positional reproduction, greatly reducing operational difficulty and collision risks. It significantly improves the efficiency of intraoperative image acquisition, shortens surgical assistance time, and avoids invalid exposure through precise path planning, helping to reduce radiation doses for patients and medical staff. Furthermore, the integrated image processing can guide image matching based on known precise displacement information, greatly improving the speed and robustness of the stitching algorithm. Even with small overlapping areas, accurate and seamless stitching can be achieved, ultimately providing doctors with high-quality panoramic diagnostic images and significantly improving the accuracy and safety of surgery.

[0096] Example 3 In a preferred embodiment, this application also provides an electronic device, the electronic device comprising: The computer device includes a memory and a processor, wherein the memory stores computer-readable instructions that, when executed by the processor, implement the image stitching method for a mobile C-arm. The computer device can be broadly categorized as a server, terminal, or any other electronic device with the necessary computing and / or processing capabilities. In one embodiment, the computer device may include a processor, memory, network interface, communication interface, etc., connected via a system bus. The processor of the computer device can be used to provide the necessary computing, processing, and / or control capabilities. The memory of the computer device may include a non-volatile storage medium and internal memory. The non-volatile storage medium may store an operating system, computer programs, etc. The internal memory can provide an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The network interface and communication interface of the computer device can be used to connect and communicate with external devices via a network. When the computer program is executed by the processor, it performs the steps of the method of the present invention.

[0097] This invention can be implemented as a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, causes the steps of the methods of embodiments of the invention to be performed. In one embodiment, the computer program is distributed across multiple network-coupled computer devices or processors, such that the computer program is stored, accessed, and executed in a distributed manner by one or more computer devices or processors. A single method step / operation, or two or more method steps / operations, may be executed by a single computer device or processor or by two or more computer devices or processors. One or more method steps / operations may be executed by one or more computer devices or processors, and one or more other method steps / operations may be executed by one or more other computer devices or processors. One or more computer devices or processors may execute a single method step / operation, or execute two or more method steps / operations.

[0098] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0099] The technical features described above can be combined arbitrarily. Although not all possible combinations of these technical features are described, any combination of these technical features should be considered to be covered by this specification, provided that such combination does not contain contradictions.

[0100] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An image stitching system for a mobile C-arm, characterized in that, include: A lateral movement unit is disposed on the image chain assembly of the movable C-arm and is used to drive the image chain assembly to perform lateral linear movement. The image chain assembly includes an X-ray tube and a flat panel detector. The control unit is communicatively connected to the lateral movement unit and is used to control the lateral movement unit to move the image chain component to multiple target acquisition positions according to the movement planning path. The image processing unit is communicatively connected to the control unit and the flat panel detector, and is used to perform image acquisition at multiple target acquisition locations and to stitch the acquired sequence of images.

2. The image stitching system for a mobile C-arm according to claim 1, characterized in that, The image stitching system also includes a distance detection device, which is installed on the X-ray tube and / or the flat panel detector, and is used to measure the distance from the target imaging area to the X-ray tube and / or the flat panel detector.

3. The image stitching system for a mobile C-arm according to claim 1, characterized in that, The control unit includes an industrial computer; The industrial control computer includes an image stitching planning module and a position control module. The image stitching planning module is used to generate a movement planning path, and the position control module is used to generate control commands based on the movement planning path.

4. The image stitching system for a mobile C-arm according to claim 3, characterized in that, The control unit includes a linear drive control module and a position feedback module; The linear drive control module is communicatively connected to the position control module. The linear drive control module is used to receive the control command and drive the lateral movement unit to move the image chain component to multiple target acquisition positions according to the movement planning path. The position feedback module is used to monitor and provide real-time position information of the image chain components.

5. The image stitching system for a mobile C-arm according to claim 4, characterized in that, The image processing unit includes an image acquisition module, an image matching module, and an image stitching module; The image acquisition module is used to receive raw image data from the flat panel detector and perform preprocessing. The image matching module is used to determine the overlapping area of ​​adjacent images based on the image chain component movement position information provided by the control unit, and to calculate the translation relationship between images within the overlapping area using computer vision algorithms. The image stitching module is used to merge multiple images into a stitched panoramic image according to the translation relationship.

6. The image stitching system for a mobile C-arm according to claim 1, characterized in that, The image stitching system also includes a display and interaction unit for displaying the stitched image and providing functions such as image scaling, panning, window width and window level adjustment, and saving in DICOM format.

7. An image stitching method for a mobile C-arm, characterized in that, The image stitching system for a mobile C-arm as described in claim 1, wherein the image stitching method includes: S100: Receive a control command including the image stitching range, and plan multiple target acquisition positions and movement planning paths required for the image chain component of the mobile C-arm to perform sequential image acquisition according to the control command. S200: Control the lateral movement unit set on the mobile C-arm, drive the image chain assembly to move sequentially to each of the target acquisition positions according to the movement planning path, and perform image acquisition; S300. Perform feature matching and stitching processing on the acquired sequence images to generate the stitched image.

8. The image stitching method for a mobile C-arm according to claim 7, characterized in that, The method for planning multiple target acquisition positions and movement planning paths required for the image chain assembly of the mobile C-arm to acquire sequential images includes: The distance from the target imaging area to the X-ray tube and / or the flat panel detector is measured by a distance detection device; The size of the flat panel detector is obtained, and the coverage area of ​​a single image acquisition is calculated based on the size of the flat panel detector, the distance from the X-ray tube to the flat panel detector, and the distance from the imaging part to the X-ray tube. Based on the coverage area of ​​the image acquisition, the start and end positions of the image acquisition are determined, and control instructions containing the image stitching range are generated according to the start and end positions. Based on the generated control instructions containing the image stitching range, multiple target acquisition positions and movement planning paths are automatically planned.

9. The image stitching method for a mobile C-arm according to claim 7, characterized in that, The method for performing feature matching and stitching processing on the acquired sequence images to generate a stitched image includes: The system receives raw image data from the flat panel detector and performs preprocessing to obtain a preprocessed image sequence. In the image sequence, the overlapping region of adjacent images is determined, and the translation relationship between the images is calculated using computer vision algorithms within the overlapping region; Multiple images are merged into a stitched panoramic image based on the translation relationship.

10. The image stitching method for a mobile C-arm according to claim 9, characterized in that, The step of fusing multiple images into a stitched panoramic image based on the translation relationship further includes: Image edge fusion processing is performed on the overlapping areas of image stitching to eliminate stitching marks.

11. An electronic device, characterized in that, include: Memory; The processor, wherein the memory stores computer-readable instructions that, when executed by the processor, implement the image stitching method for a mobile C-arm according to any one of claims 7 to 10.

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