A calibration device for industrial CT adapters and detectors

Abstract

This application relates to the technical field of industrial CT calibration, and in particular to a calibration device for an industrial CT adapter and calibration detector. The device includes a sliding stage, on which a transmitter, a slide block, and a detector are sequentially arranged. A partition calibrator is mounted on the detector, used for independent calibration of different areas of the detector. The partition calibrator includes a frame rotatably connected to a support, within which a calibration area is constructed. The frame can be flipped to align the calibration area with the detector's sensor. A shielding drive is mounted on the frame, and a shielding plate is movably mounted on the frame via the shielding drive. This invention forms a closed calibration space and filters stray scattered rays through a multi-level combination of a shielding frame, shielding blocks, and through-holes in the baffle. Combined with a quarter-notch subdivision calibration unit, it achieves pixel-level fine calibration, accurately identifies and corrects sensitivity deviations and dark current anomalies in individual pixels, and improves the overall calibration accuracy of the detector.

Description

Technical Field

[0001] This application relates to the technical field of industrial CT calibration, and in particular to an industrial CT adapter calibration detector calibration device. Background Technology

[0002] Industrial CT is an advanced non-destructive testing technology. Based on the penetrating characteristics of X-rays or gamma rays, combined with computed tomography and 3D reconstruction algorithms, it can clearly present the internal structure, defects, assembly relationships and dimensional information of the workpiece without damaging it.

[0003] The industrial CT adapter calibration detector is composed of a large number of pixel units. When the cone beam of X-ray emitted by the X-ray tube passes through the workpiece being measured, the intensity of the X-ray at different locations will change due to the differences in the internal density and thickness of the workpiece. The pixel units of the detector convert these X-rays of different intensities into electrical signals, which are then converted from analog to digital to generate digital projection data, providing the original basis for subsequent image reconstruction.

[0004] For example, the phantom and method for calibrating and standardizing the geometric parameters of a flat-panel CT scanner, as described in application number CN202410059068.0, involves collecting and extracting projection data of the phantom at a specific projection angle. Based on the phantom projection data and the phantom data, key geometric parameters are determined: the distance from the focal point to the detector, the distance from the focal point to the scan center, the detector channel position corresponding to the projection of the focal point through the scan center onto the detector, and the closest distance from the focal point to the detector, which is the channel position corresponding to the vertical projection of the focal point onto the detector. This determines the offset angle of the detector in the system's rotation direction and the deflection angle of the detector itself. After determining the corresponding parameters, the geometric dimensions are adjusted accordingly to bring the geometric parameters of the flat-panel CT scanner to the optimal state, thereby eliminating artifacts in the reconstructed image caused by inaccurate geometric parameters.

[0005] However, existing technologies for calibrating detectors for industrial CT scanners often focus on adjusting parameters such as position, angle, and rotation center, easily overlooking the inherent defects of the detector itself. Since the detector is not a complete monolithic structure but rather an array of countless tiny pixels, these pixels inherently exhibit individual differences. Some pixels are highly sensitive to X-rays, while others are relatively insensitive. Even without X-ray exposure, some pixels may exhibit slight background luminescence (i.e., dark current).

[0006] Current technologies only calibrate position, angle, and rotation center, failing to address microscopic errors such as pixel sensitivity differences and dark current. Even with macroscopic parameters adjusted to precision, inherent errors at the pixel level still exist, leading to deviations in subsequent scanned images and failing to meet the actual needs of high-precision detection and measurement in industrial CT.

[0007] Based on this, as stated above, there is still room for improvement in the existing technology for calibrating industrial CT adapters and calibration detectors. Summary of the Invention

[0008] To address the aforementioned technical problems, this application provides an industrial CT adapter calibration detector calibration device, employing the following technical solution:

[0009] An industrial CT adapter calibration detector calibration device includes a sliding stage, on which a support, a slide block and a bracket are sequentially arranged. The detector is mounted on the sliding stage via the bracket. A transmitter is mounted on the support, the detector is mounted on the bracket, and a zone calibrator is mounted on the bracket. The zone calibrator is used to independently calibrate different areas of the detector.

[0010] The partition calibrator includes a frame rotatably connected to a bracket, a calibration area constructed inside the frame, the frame can be flipped to make the calibration area correspond to the detector, a shielding drive is provided on the frame, and a shielding plate is movably set on the frame through the shielding drive.

[0011] By using a shielding drive to move the shielding plate within the calibration area, the shielded or exposed areas in the calibration area can be adjusted, thereby achieving selective calibration of different detection areas of the detector.

[0012] Preferably, the partition calibrator also includes a window on the shielding plate that defines a calibration area on the detector that is not obscured by the shielding plate.

[0013] Preferably, a shielding frame is provided inside the window, and the shielding frame is connected to the shielding drive component, with one end of the shielding frame extending to the surface of the detector's detection area.

[0014] Preferably, the shielding drive component includes a crossbeam slidably disposed on the frame, and a vertical beam slidably disposed on the frame, the crossbeam and the vertical beam being relatively perpendicular to each other, and the crossbeam and the vertical beam being slidably connected to each other to form a connection point;

[0015] The shielding frame is located at the connection point and is slidably connected to the crossbeam and the vertical beam.

[0016] Preferably, a crossbeam screw that is threadedly connected to the crossbeam is rotatably provided on the frame, and a vertical beam screw that is threadedly connected to the vertical beam is rotatably provided on the frame.

[0017] Preferably, the shielding plate is provided with shielding components corresponding to the shielding frame;

[0018] The shielding component includes an unshielded area constructed within the shielding frame. A flap corresponding to the unshielded area is rotatably mounted on the shielding plate. A rotating plate is rotatably mounted on the flap, and a shielding block corresponding to the unshielded area is embedded in the rotating plate.

[0019] Preferably, the shielding block has a notch, which occupies one-quarter of the area of ​​the unshielded area.

[0020] Preferably, a baffle is rotatably mounted on the transmitter to block the transmitter's transmission path, and the baffle has through holes corresponding to the shielding frame.

[0021] Preferably, the support is slidably mounted on the sliding platform, and the support is a telescopic structure.

[0022] In summary, this application includes at least one of the following beneficial technical effects:

[0023] 1. This invention forms a closed calibration space and filters stray scattered lines through the multi-level cooperation of the shielding frame, shielding block, and baffle through holes. Combined with the quarter-notch subdivision calibration unit, it achieves pixel-level fine calibration, accurately identifies and corrects the sensitivity deviation and dark current anomaly of individual pixels, and improves the overall calibration accuracy of the detector.

[0024] 2. This invention forms a closed calibration space and filters stray scattered lines through the multi-level cooperation of the shielding frame, shielding block, and baffle through-hole. Combined with the quarter-notch subdivision calibration unit, it achieves pixel-level fine calibration, accurately identifies and corrects the sensitivity deviation and dark current anomaly of individual pixels, and improves the overall calibration accuracy of the detector.

[0025] 3. The closed calibration space of this invention eliminates X-ray crosstalk and environmental interference, ensuring that the collected projection data and dark current data are the true response data of the target calibration area, avoiding errors and misjudgments, providing accurate basis for pixel parameter compensation, and ensuring the high-precision detection and measurement needs of subsequent industrial CT. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the present invention.

[0027] Figure 2 This is a schematic diagram of the partition calibrator of the present invention.

[0028] Figure 3 This is a cross-sectional view of the partition calibrator of the present invention.

[0029] Figure 4 This is a schematic diagram of the structure between the bracket and the shielding drive component of the present invention.

[0030] Figure 5 This is a schematic diagram of the structure of the shielding drive component of the present invention.

[0031] Figure 6 This is a schematic diagram of the structure between the shielding plate and the shielding component of the present invention.

[0032] Figure 7 This is a schematic diagram of the shielding component of the present invention.

[0033] Figure 8 This is a schematic diagram of the structure between the baffle and the through hole of the present invention.

[0034] Explanation of reference numerals in the attached drawings: 1. Sliding stage; 2. Support; 3. Slide; 4. Bracket; 5. Transmitter; 6. Detector; 7. Zone calibrator; 71. Frame; 72. Calibration area; 73. Shielding plate; 74. Window; 75. Shielding frame; 8. Shielding drive component; 81. Crossbeam; 82. Vertical beam; 83. Connection point; 84. Crossbeam screw; 85. Vertical beam screw; 9. Shielding component; 91. Unshielded area; 92. Flip plate; 93. Turning plate; 94. Shielding block; 95. Notch; 96. Baffle; 97. Through hole. Detailed Implementation

[0035] The following is in conjunction with the appendix Figures 1 to 8 This application will be described in further detail.

[0036] This application discloses an industrial CT adapter calibration detector calibration device. By installing a standard calibration phantom and completing the coaxial alignment of the transmitter, calibration phantom and detector, as well as the precise debugging of the zone calibrator, the device performs micro-calibration, global zone-by-zone coverage calibration and macro-parameter calibration of the detector pixels, and then resets each component. This achieves precise correction of micro-errors at the detector pixel level, meeting the high-precision detection requirements of industrial CT.

[0037] Reference Figure 1 , Figure 2 and Figure 3 As shown, an industrial CT adapter calibration device for a detector 6 includes a sliding stage 1, on which a support 2, a slide 3, and a bracket 4 are sequentially arranged. The detector 6 is mounted on the sliding stage 1 via the bracket 4. A transmitter 5 is mounted on the support 2, and the detector 6 is mounted on the bracket 4. A zone calibrator 7 is mounted on the bracket 4, which is used to independently calibrate different areas of the detector 6.

[0038] When calibrating the positioning detector 6, the sliding stage 1 serves as the basic bearing and positioning reference. By sequentially arranging the support 2, slide 3, and bracket 4 on the sliding stage 1, the transmitter 5, the calibration model (slide 3 is used for installation), and the detector 6 are made coaxial and arranged in sequence, ensuring that the rays emitted by the transmitter 5 can be directed to the detector 6 along a preset path. The support 2 provides a fixed mounting position for the transmitter 5 to ensure the positional stability of the ray emission, while the bracket 4 reliably fixes the detector 6, placing the detector 6 in a precise position for ray reception.

[0039] By adding a zone calibrator 7 to the support 4, the different detection areas of the detector 6 can be independently calibrated and corrected. This allows for the detection and correction of sensitivity deviations and inconsistent responses in each area of ​​the detector 6, achieving precise calibration of each area of ​​the detector 6 and improving the overall calibration accuracy of the detector 6. This meets the high-precision, zone-specific calibration requirements of industrial CT for the detector 6.

[0040] Reference Figure 3 , Figure 4 and Figure 5 As shown, specifically, the partition calibrator 7 includes a frame 71 rotatably connected to the bracket 4. A calibration area 72 is constructed inside the frame 71. The frame 71 can be flipped to align the calibration area 72 with the detector 6. A shielding drive 8 is provided on the frame 71, and a shielding plate 73 is movably mounted on the frame 71 through the shielding drive 8. The calibration area 72 formed inside the frame 71 provides working space for the partition calibration of the detector 6. The frame 71 can be flipped around the bracket 4 to achieve rapid alignment and disassembly between the calibration area 72 and the detection surface of the detector 6.

[0041] The shielding drive 8 moves the shielding plate 73 within the calibration area 72 to adjust the shielded or exposed areas in the calibration area 72, thereby achieving selective calibration of different detection areas of the detector 6.

[0042] The partition calibrator 7 also includes a window 74 on the shielding plate 73, which defines a calibration area on the detector 6 that is not blocked by the shielding plate 73, so as to adjust the calibration area 72 that is blocked or exposed by the shielding plate 73.

[0043] Before calibration, frame 71 is flipped to the working position so that calibration area 72 is precisely aligned with the pixel array of detector 6. A standard calibration phantom with known density and geometric features is installed on slide 3 to ensure that transmitter 5, calibration phantom, calibration area 72, and pixel array of detector 6 are arranged coaxially, establishing a precise benchmark for micro-calibration at the pixel level, while avoiding interference from macro-position and angle errors on micro-calibration.

[0044] The shielding drive 8 on the frame 71 drives the shielding plate 73 of the window 74 to move within the calibration area 72. The window 74 enables area-by-area and point-by-point shielding and exposure of the pixel array of the detector 6. The window 74 only allows rays to pass through and illuminate a single local pixel area of ​​the detector 6 (which can accurately cover several pixels). The rest of the shielding plate 73 completely blocks the rays, ensuring that a single calibration focuses only on this local pixel area and avoids mutual interference of errors between adjacent pixels.

[0045] Emitter 5 emits X-rays of stable intensity, which penetrate the standard calibration phantom and illuminate only the local pixel area to be calibrated through window 74. The pixels in this area acquire the standard projection data of the calibration phantom. The acquired projection data is compared with the theoretical standard projection data of the corresponding area of ​​the calibration phantom to accurately identify the sensitivity deviation of each pixel in this area (pixels with high or low sensitivity will show grayscale abnormalities). The system algorithm then performs targeted compensation on the response parameters of the pixels in this area to make the sensitivity of each pixel more consistent.

[0046] With the transmitter 5 not emitting X-rays (no radiation exposure), keep window 74 aligned with the local pixel area to be calibrated and collect the background luminescence data (i.e. dark current data) of the pixels in that area; compare the collected dark current data with the normal background value of the pixels to identify pixels with excessive dark current and abnormal background luminescence, and use algorithms to cancel and correct the dark current of such pixels to eliminate background interference in the absence of radiation.

[0047] The masking drive 8 continuously drives the masking plate 73 to move, so that the window 74 sequentially covers all local areas of the pixel array of the detector 6, repeating the above sensitivity calibration and dark current calibration process, to achieve area-by-area and pixel-by-pixel micro-calibration of the entire pixel array of the detector 6.

[0048] After calibration, the existing macroscopic parameters (position, angle, rotation center) are combined to achieve macroscopic positioning calibration and microscopic pixel calibration, completely eliminating the influence of microscopic errors such as pixel sensitivity differences and dark current on subsequent scanning images, ensuring that the image output by detector 6 has uniform grayscale and accurate data, and meeting the actual needs of high-precision detection and measurement in industrial CT.

[0049] Reference Figure 4 and Figure 5 As shown, a shielding frame 75 is provided inside the window 74, and the shielding frame 75 is connected to the shielding drive component 8. One end of the shielding frame 75 extends to the surface of the detection area of ​​the detector 6 to form a closed local calibration space, which completely blocks the leakage of rays from the edge of the window 74, prevents adjacent pixels of the non-calibrated area 72 from being irradiated by rays, avoids calibration data interference caused by ray crosstalk, and ensures that only the real response data of the local pixels corresponding to the window 74 are collected in a single calibration.

[0050] It also isolates external stray rays, light and other environmental interference, and reduces the impact of dark current of adjacent pixels on the current calibration area 72, avoiding misjudgment of dark current calibration; in addition, it precisely limits the range of pixel area to be calibrated, making the detection and correction of sensitivity deviation and dark current more targeted, and improving the accuracy and reliability of pixel-level micro error calibration.

[0051] Specifically, the shielding drive component 8 includes a crossbeam 81 slidably disposed on the frame 71, and a vertical beam 82 slidably disposed on the frame 71. The crossbeam 81 and the vertical beam 82 are perpendicular to each other, and the crossbeam 81 and the vertical beam 82 are slidably connected to each other to form a connection point 83.

[0052] The shielding frame 75 is located at the connection point 83 and is slidably connected to the horizontal beam 81 and the vertical beam 82. The horizontal beam 81 and the vertical beam 82 intersect perpendicularly on the frame 71 and slide together. The connection point 83 provides a precise installation and movement positioning reference for the shielding frame 75, allowing the shielding frame 75 to move horizontally and vertically within the calibration area 72 along with the connection point 83. This enables the selection of any local area of ​​the pixel array of the detector 6 without blind spots, and adapts to the pixel partition calibration requirements of detectors 6 of different specifications.

[0053] A crossbeam screw 84, threadedly connected to the crossbeam 81, is rotatably mounted on frame 71, and a vertical beam screw 85, threadedly connected to the vertical beam 82, is also rotatably mounted on frame 71. The shielding frame 75 is slidably connected to both the crossbeam 81 and the vertical beam 82. Through the threaded transmission of the crossbeam screw 84 and the vertical beam screw 85, rotating the screws can drive the crossbeam 81 and the vertical beam 82 to move linearly along frame 71, thereby causing the shielding frame 75 to perform controllable dual-axis movement at connection point 83. This precisely adjusts the corresponding position of the shielding frame 75 on the detection surface of detector 6, achieving precise delineation of a small area composed of one or several pixels, meeting the fine positioning requirements of pixel-level micro-calibration.

[0054] Reference Figure 5 and Figure 6 As shown, the shielding plate 73 is provided with a shielding component 9 corresponding to the shielding frame 75; the shielding component 9 can form a secondary shielding inside the shielding frame 75. Based on the local calibration area 72 already defined by the shielding frame 75, the secondary shielding by the shielding component 9 leaves only a small area within the shielding frame 75, further reducing the effective calibration range through which the radiation can pass. The original local calibration area 72 is refined into smaller calibration units, which can accurately correspond to a single or very few pixels of the detector 6, achieving pixel-level fine calibration.

[0055] Specifically, the shielding component 9 includes an unshielded area 91 constructed within the shielding frame 75, a flap 92 corresponding to the unshielded area 91 rotatably disposed on the shielding plate 73, a rotating plate 93 rotatably disposed on the flap 92, and a shielding block 94 corresponding to the unshielded area 91 embedded in the rotating plate 93.

[0056] The shielding block 94 has a notch 95, which occupies one-quarter of the area of ​​the unshielded area 91. By rotating the flip plate 92 and the rotating plate 93 in two stages, the position of the shielding block 94 in the unshielded area 91 can be flexibly adjusted. With the notch 95 on the shielding block 94 occupying one-quarter of the area of ​​the unshielded area 91, secondary fine-grained zoning shielding of the unshielded area 91 can be achieved.

[0057] Reference Figure 7 As shown, a baffle 96 is rotatably mounted on the emitter 5, which blocks the emission path of the emitter 5. The baffle 96 has a through hole 97 corresponding to the shielding frame 75. The baffle 96 can block the emission path of the emitter 5, realize the on / off control of the radiation emission, and facilitate the quick cutting off or conducting of radiation when switching between dark current calibration and sensitivity calibration procedures.

[0058] A through-hole 97 corresponding to the shielding frame 75 is formed on the baffle 96. The rays can only be emitted through the through-hole 97, forming a multi-level ray channel alignment with the notch 95 of the shielding frame 75 and the shielding block 94. This further filters out stray rays emitted by the emitter 5, preventing excess rays from deviating from the preset calibration path. This ensures that only the standard rays precisely aligned with the notch 95 can illuminate the target calibration pixel of the detector 6, completely eliminating calibration data deviations caused by stray rays and further improving the accuracy of pixel-level calibration.

[0059] During operation, the drive flap 92 rotates and fits against the shielding plate 73, causing the shielding block 94 to embed into the unshielded area 91 within the shielding frame 75. The shielding block 94 provides initial and secondary shielding to the unshielded area 91, leaving only a gap 95 on the shielding block 94, occupying one-quarter of the area of ​​the unshielded area 91, as the sole effective X-ray channel, precisely limiting the calibration area 72 to a very small range. This action locks the initial target calibration pixel area, preventing non-target pixels from being irradiated by X-rays, ensuring that the initially acquired detector 6 response data and dark current data correspond only to a single or very few pixels covered by the gap 95, providing precise spatial constraints for the detection of microscopic errors in a single pixel.

[0060] The flip plate 92 first rotates away from the shielding plate 73, releasing the engagement between the shielding block 94 and the unshielded area 91, reserving space for the switching of the shielding block 94's position. Then, the rotating plate 93 drives the shielding block 94 to rotate one position (90 degrees), changing the relative position of the notch 95 of the shielding block 94 within the unshielded area 91, completing the precise switching of the calibration pixel area. The flip plate 92 rotates again and engages with the shielding plate 73, and the shielding block 94 re-embeds into the unshielded area 91. The new notch 95 position corresponds to another new set of target pixel areas on the detector 6. Repeating this process sequentially switches one-quarter of the effective calibration area 72 within the unshielded area 91, achieving position-by-position, full-coverage fine calibration of all pixels within the coverage area of ​​the shielding frame 75. This process completes the detection and correction of sensitivity deviations and dark current anomalies in each subdivided pixel area, completely eliminating microscopic errors in the detector 6's pixel array.

[0061] The implementation principle of this invention is as follows:

[0062] Step 1: Install the standard calibration phantom on the slide block 3, ensuring that the transmitter 5, calibration phantom, and detector 6 are arranged coaxially; flip the frame 71 of the partition calibrator 7 to the working position, aligning its calibration area 72 with the pixel array of the detector 6; rotate the crossbeam 81 and the vertical beam screw 85 to drive the shielding frame 75 to move along both axes to fit the detection surface of the detector 6, defining the first calibration area 72; drive the flip plate 92 to fit the shielding plate 73, so that the shielding block 94 is embedded in the unshielded area 91, and lock the subdivision calibration pixels through the notch 95, while rotating the baffle 96 to align the through hole 97 with the ray path, completing the calibration preparation.

[0063] Step 2: The X-ray emitted by the transmitter 5 is turned on and irradiates the target pixel area through the through hole 97 of the baffle 96, the shielding frame 75, and the notch 95 of the shielding block 94. Projection data is collected and compared with the standard value to correct the pixel sensitivity deviation. The X-ray is then cut off, and the dark current data of the area is collected to correct abnormal dark current. The flip plate 92 and the rotating plate 93 are driven to switch the position of the notch 95 of the shielding block 94. The above actions are repeated to complete the calibration of all subdivided pixels in the area covered by the current shielding frame 75.

[0064] Step 3: Rotate the horizontal beam 81 and the vertical beam screw 85 to drive the shielding frame 75 to move and switch the local calibration area 72. Repeat step 2 to gradually cover the entire pixel array of the detector 6, complete the micro-calibration of all pixels area by area, and at the same time complete the calibration of macro parameters (position, angle, rotation center) in combination with existing technology.

[0065] Step 4: After calibration, flip frame 71 to detach from detector 6, reset components such as flip plate 92, rotating plate 93, shielding frame 75, and baffle 96, remove the standard calibration model, and complete the entire calibration process.

[0066] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A calibration device for an industrial CT adapter detector, comprising a sliding stage, wherein a support, a slide block, and a bracket are sequentially arranged on the sliding stage, and the detector is mounted on the sliding stage via the bracket, characterized in that: The support is equipped with a transmitter, the bracket is equipped with a detector, and the bracket is equipped with a zone calibrator. The zone calibrator is used to independently calibrate different areas of the detector. The partition calibrator includes a frame rotatably connected to a bracket, a calibration area constructed inside the frame, the frame can be flipped to make the calibration area correspond to the detector of the detector, a shielding drive is provided on the frame, and a shielding plate is movably set on the frame through the shielding drive. The shielding drive moves the shielding plate within the calibration area to adjust the shielded or exposed areas in the calibration area, thereby selectively calibrating different detection areas of the detector. The partition calibrator also includes a window on the shielding plate, which creates a calibration area for the detector that is not blocked by the shielding plate. A shielding frame is set inside the window, and the shielding frame is connected to the shielding drive. The shielding drive includes a crossbeam slidably mounted on the frame and a vertical beam slidably mounted on the frame. The crossbeam and the vertical beam are perpendicular to each other and are slidably connected to form a connection point. The shielding frame is located at the connection point and is slidably connected to the horizontal and vertical beams; A crossbeam screw rod, threadedly connected to the crossbeam, is rotatably mounted on the frame, and a vertical beam screw rod, threadedly connected to the vertical beam, is also rotatably mounted on the frame.

2. The calibration device for an industrial CT adapter detector according to claim 1, characterized in that: One end of the shielding frame extends to the surface of the detector's detection area.

3. The calibration device for an industrial CT adapter detector according to claim 1, characterized in that: The shielding plate is equipped with shielding components that correspond to the shielding frame. The shielding component includes an unshielded area constructed within the shielding frame. A flap corresponding to the unshielded area is rotatably mounted on the shielding plate. A rotating plate is rotatably mounted on the flap, and a shielding block corresponding to the unshielded area is embedded in the rotating plate.

4. A calibration device for an industrial CT adapter detector according to claim 3, characterized in that: The shielding block has a gap in its construction, which occupies one-quarter of the area of ​​the unshielded zone.

5. A calibration device for an industrial CT adapter detector according to claim 4, characterized in that: A baffle is rotatably mounted on the transmitter to block the transmitter's transmission path. The baffle has through holes that correspond to the shielding frame.

6. A calibration device for an industrial CT adapter detector according to claim 5, characterized in that: The support is slidably mounted on the sliding platform, and the support is a telescopic structure.

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