A non-contact method and system for measuring concentricity straightness of an IVD sample needle tube

Abstract

The application relates to the technical field of IVD sample adding needle tube measurement, and discloses a non-contact measurement method and system for the concentricity and straightness of an IVD sample adding needle tube, which rotates the IVD sample adding needle tube under air floating support, carries out multi-axial and multi-angle synchronous scanning by combining a low-coherence white light interference technology, obtains the full-perimeter surface profile of the needle tube, and constructs three-dimensional space data. The spatial axis is determined by recognizing geometric features, the concentricity and straightness are calculated, and quality judgment is completed by comparing with a tolerance threshold. The method realizes true non-contact measurement by air floating and white light interference, avoids friction damage and deformation of the needle tube caused by contact type measurement, simultaneously determines the spatial axis based on full-size three-dimensional reconstruction, and overcomes the problems of traditional optical schemes, such as difficulty in restoring three-dimensional axes, surface reflection interference and ellipsoidal degree interference, and data distortion.

Description

Technical Field

[0001] This application relates to the field of IVD sample dispensing needle measurement technology, and more specifically, to a non-contact measurement method and system for the concentric straightness of IVD sample dispensing needles. Background Technology

[0002] In the manufacturing of precision medical devices, particularly the production of sample dispensing needles for in vitro diagnostic (IVD) equipment, the geometric accuracy of the product, especially concentricity and straightness, is crucial to ensuring its functional reliability and safe use. Currently, the industry generally relies on contact-based mechanical probe scanning or plug gauge methods to inspect the form and position tolerances of needles. These methods are not only prone to causing microscopic damage or deformation to the needle tip due to frictional resistance from physical contact, affecting subsequent reliability, but also limited by sampling frequency and mechanical inertia, making it difficult to achieve full-size, high-density continuous data acquisition for slender, tiny needles, thus failing to meet the demands of modern production lines for high-precision, non-destructive testing.

[0003] The main problems with existing technologies are: contact measurement methods involve significant "probe-workpiece" interaction with micro-needles, making the inspection process itself a potential source of product scrap; simultaneously, traditional optical measurement schemes are mostly limited to two-dimensional projection or single-view imaging, making it difficult to accurately reproduce the three-dimensional spatial axis shape of the needle, and are easily affected by surface reflections, slight bends, and ellipticity of the needle, resulting in distorted measurement data. For example, if there is slight reflection on the needle surface, traditional two-dimensional images may not accurately capture its true edges, leading to deviations in measurement results. In addition, the statistical process control (SPC) mode, which relies on manual sampling, has the risk of missed inspections and cannot meet the requirements of 100% online full inspection and real-time quality traceability for every product in the context of smart manufacturing, making it difficult to further improve production efficiency and yield.

[0004] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0005] This application discloses a non-contact measurement method and system for the concentric straightness of IVD sample dispensing needles, aiming to solve the problems of damage to micro needles caused by contact measurement in the prior art, the difficulty of accurately restoring the three-dimensional spatial axis shape by traditional optical measurement, and the risk of missed detection in manual sampling mode.

[0006] The technical solution of this application is as follows: In a first aspect, this application discloses a non-contact method for measuring the concentricity straightness of an IVD sample dispensing syringe, specifically including: Obtain the IVD sample dispensing syringe to be tested; The IVD sample dispensing syringe to be tested is placed in an air-float support state, and the IVD sample dispensing syringe to be tested is controlled to rotate around the axis of the IVD sample dispensing syringe to be tested at a preset angular velocity. For the IVD sample dispensing needle under test, which is in an air-bearing support state and rotates around the axis of the IVD sample dispensing needle under test at a preset angular velocity, a low-coherence white light interferometry method is used to simultaneously scan from multiple axial positions and multiple angles around the axis of the IVD sample dispensing needle under test to obtain surface contour information covering the entire circumference of the IVD sample dispensing needle under test. The surface contour information is converted into three-dimensional spatial data, and a measurement coordinate system is established that is fixed to the IVD sample dispensing syringe under test; The three-dimensional spatial data is processed to identify the geometric features of the IVD sample dispensing syringe under test, and the spatial axis of the IVD sample dispensing syringe under test is determined based on the geometric features. Calculate the concentricity and straightness of the IVD sample dispensing syringe to be tested according to the spatial axis; The concentricity and straightness are compared with the corresponding concentricity tolerance threshold and straightness tolerance threshold, respectively, and the quality of the IVD sample dispensing syringe to be tested is judged according to the comparison results.

[0007] Secondly, this application also discloses a non-contact measurement system for the concentricity straightness of an IVD sample dispensing syringe, specifically including: A rotating support module is used to acquire the IVD sample dispensing needle to be tested, place the IVD sample dispensing needle to be tested in an air-float support state, and control the IVD sample dispensing needle to be tested to rotate around the axis of the IVD sample dispensing needle to be tested at a preset angular velocity. The optical scanning module is used to scan the IVD sample tube under test, which is in an air-bearing state and rotates around the axis of the IVD sample tube under test at a preset angular velocity, simultaneously from multiple axial positions and multiple angles around the axis of the IVD sample tube under test in a low-coherence white light interferometry method, to obtain surface contour information covering the entire circumference of the IVD sample tube under test. The data processing module is used to receive the surface contour information, convert the surface contour information into three-dimensional spatial data, establish a measurement coordinate system fixed to the IVD sample dispensing needle under test, process the three-dimensional spatial data to identify the geometric features of the IVD sample dispensing needle under test, and determine the spatial axis of the IVD sample dispensing needle under test according to the geometric features. The calculation and judgment module is used to calculate the concentricity and straightness of the IVD sample dispensing syringe to be tested according to the spatial axis, compare the concentricity and straightness with the corresponding concentricity tolerance threshold and straightness tolerance threshold respectively, and judge the quality of the IVD sample dispensing syringe to be tested according to the comparison results.

[0008] This application discloses a non-contact measurement method and system for the concentricity and straightness of an IVD sample dispensing syringe. The IVD sample dispensing syringe is rotated under an air-bearing support, and multi-axial, multi-angle synchronous scanning is performed using low-coherence white light interferometry to acquire the full circumference surface profile of the syringe and construct three-dimensional spatial data. The spatial axis is determined by identifying geometric features, concentricity and straightness are calculated, and the results are compared with tolerance thresholds to complete quality judgment.

[0009] This method achieves truly non-contact measurement using air flotation and white light interferometry, avoiding frictional damage and deformation to the needle caused by contact measurement. Simultaneously, it determines the spatial axis based on full-size 3D reconstruction, overcoming the problems of traditional optical solutions that rely on 2D projection / single-view imaging, struggle to reconstruct the 3D axis, and suffer from data distortion due to surface reflection and ellipticity interference. The entire solution meets the demands of modern production lines for high precision, non-destructive testing, 100% online full inspection, and real-time quality traceability, significantly improving production efficiency and yield. Attached Figure Description

[0010] Figure 1 This is a flowchart illustrating a non-contact measurement method for the concentric straightness of an IVD sample dispensing syringe provided in an embodiment of the present invention. Figure 2 This is a flowchart of a method for determining the spatial axis of the IVD sample dispensing syringe based on the geometric features provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a non-contact measurement system for the concentric straightness of an IVD sample dispensing syringe provided in an embodiment of the present invention. Detailed Implementation

[0011] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0012] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0013] In the field of precision medical device manufacturing, especially in the production of sample dispensing needles used in in vitro diagnostic (IVD) equipment, the geometric accuracy of the product, particularly concentricity and straightness, is crucial to ensuring its functional reliability and safety of use. Traditional existing testing methods generally rely on contact-based mechanical probe scanning or plug gauge methods. These methods are prone to causing microscopic damage or deformation to the needle tip due to frictional resistance from physical contact, affecting subsequent reliability. Furthermore, they are limited by sampling frequency and mechanical inertia, making it difficult to achieve full-size, high-density continuous data acquisition for slender, micro-needles, thus failing to meet the demands of modern production lines for high-precision, non-destructive testing. In addition, traditional optical measurement schemes are mostly limited to two-dimensional projection or single-view imaging, making it difficult to accurately reproduce the three-dimensional spatial axis of the needle. They are also susceptible to interference from needle surface reflections, minor bends, and ellipticity, resulting in distorted measurement data.

[0014] In this regard, refer to Figure 1 , Figure 1 This is a flowchart illustrating a non-contact measurement method for the concentricity straightness of an IVD sample dispensing syringe provided in an embodiment of the present invention, including: S11, Obtain the IVD sample dispensing syringe to be tested; S12, the IVD sample dispensing syringe to be tested is placed in an air-float support state, and the IVD sample dispensing syringe to be tested is controlled to rotate around the axis at a preset angular velocity. S13, for the IVD sample tube under test that is in the air-bearing support state and rotates around the axis of the IVD sample tube under test at the preset angular velocity, a low-coherence white light interferometry method is used to simultaneously scan from multiple axial positions and multiple angles around the axis of the IVD sample tube under test to obtain surface contour information covering the entire circumference of the IVD sample tube under test. S14, convert the surface contour information into three-dimensional spatial data, and establish a measurement coordinate system fixed to the IVD sample dispensing syringe under test; S15, process the three-dimensional spatial data, identify the geometric features of the IVD sample dispensing syringe to be tested, and determine the spatial axis of the IVD sample dispensing syringe to be tested based on the geometric features; S16, calculate the concentricity and straightness of the IVD sample dispensing syringe to be tested according to the spatial axis; S17, compare the concentricity and straightness with the corresponding concentricity tolerance threshold and straightness tolerance threshold respectively, and judge the quality of the IVD sample dispensing syringe to be tested according to the comparison results.

[0015] This application effectively avoids the potential damage to the syringe caused by traditional contact measurement through non-contact measurement, three-dimensional data reconstruction and precise axis calculation, and overcomes the limitations of traditional optical measurement in three-dimensional morphology restoration, thereby achieving high-precision, non-destructive, full-size measurement and quality judgment of the concentricity and straightness of IVD sample dispensing syringes.

[0016] The non-contact measurement method for the concentricity and straightness of IVD sample dispensing needles proposed in this application aims to provide a high-precision, non-destructive testing solution. The "IVD sample dispensing needle" refers to a precision tubular component used in in vitro diagnostic equipment for the aspiration and dispensing of liquid samples; its geometric accuracy directly affects the accuracy of diagnostic results. "Concentricity" refers to the degree to which the centers of the inner and outer walls of the needle coincide, reflecting the uniformity of the needle wall thickness; "straightness" refers to the degree to which the needle axis deviates from an ideal straight line, reflecting the bending of the needle. These geometric parameters are crucial for ensuring sample dispensing accuracy. This method, through a "non-contact" approach, avoids physical contact with the needle under test, thus preventing damage that may occur with traditional measurement methods.

[0017] Specifically, this method first requires obtaining the IVD sample syringe to be tested. This can be achieved through manual placement or automated robotic arm picking. For example, an operator places the IVD sample syringe to be tested at a designated station, or an automated system picks the IVD sample syringe to be tested from a tray.

[0018] Subsequently, the IVD sample syringe under test is placed in an air-float support state, and the IVD sample syringe is controlled to rotate around its axis at a preset angular velocity. The air-float support can be achieved by creating micropores on the support surface and introducing compressed gas to form an air film, allowing the IVD sample syringe to suspend in a frictionless or very low-friction state. Rotation control can be achieved through a rotation drive mechanism integrated with the air-float support, for example, by using magnetic drive or a micro-motor to drive the air-float platform to rotate, thereby causing the IVD sample syringe to rotate around its own axis at a constant preset angular velocity. The selection of the preset angular velocity needs to comprehensively consider measurement accuracy and efficiency; for example, it can be set to several to tens of revolutions per second.

[0019] Next, for the IVD sample syringe under test, which is in the air-bearing support state and rotating around the axis of the IVD sample syringe at the preset angular velocity, a low-coherence white light interferometry method is used to simultaneously scan from multiple axial positions and multiple angles around the axis of the IVD sample syringe to obtain surface contour information covering the entire circumference of the IVD sample syringe. Low-coherence white light interferometry is a high-precision non-contact measurement technology. Its principle is to use a broadband light source to generate interference fringes, and to determine the height information of the object surface by analyzing the phase and intensity of the interference fringes. In practice, multiple interferometric probes can be configured, which are distributed along the axis of the IVD sample syringe and arranged in an array around the axis of the IVD sample syringe. When the IVD sample syringe rotates, these probes synchronously collect data, thereby obtaining the surface contour information of the entire circumference of the IVD sample syringe.

[0020] After acquiring the surface contour information, it is converted into three-dimensional spatial data, and a measurement coordinate system is established and fixed to the IVD sample dispensing needle under test. The surface contour information typically exists in the form of point cloud data, with each point containing its three-dimensional coordinates within the measurement system. Data processing software can integrate and transform this point cloud data to form a complete three-dimensional model. The measurement coordinate system fixed to the IVD sample dispensing needle under test can be established by selecting several feature points on the IVD sample dispensing needle as references, or by fitting the geometric centerline of the IVD sample dispensing needle, ensuring the accuracy of subsequent calculations.

[0021] Further, the three-dimensional spatial data is processed to identify the geometric features of the IVD sample dispensing syringe under test, and the spatial axis of the IVD sample dispensing syringe is determined based on these geometric features. Geometric feature identification can be achieved through various point cloud processing algorithms, such as curvature analysis, edge detection, or shape fitting, to identify key geometric regions such as the inner and outer wall surfaces, tip, and root of the IVD sample dispensing syringe under test. The determination of the spatial axis is based on these identified geometric features; for example, by performing cylindrical fitting on the inner and outer wall surfaces, and then calculating the centerline of the fitted cylinder as the spatial axis of the IVD sample dispensing syringe under test.

[0022] Subsequently, the concentricity and straightness of the IVD sample dispensing syringe under test are calculated according to the spatial axis. Concentricity can be calculated by analyzing the deviation between the centerlines of the inner and outer walls of the IVD sample dispensing syringe. For example, the center positions of the inner and outer walls are measured at multiple cross-sections, and then the average or maximum distance between these centers is calculated. Straightness can be calculated by assessing the degree of deviation between the spatial axis and an ideal straight line, for example, by fitting an ideal straight line using the least squares method, and then calculating the maximum or root-mean-square distance from each point on the spatial axis to the ideal straight line.

[0023] Finally, the concentricity and straightness are compared with their corresponding concentricity tolerance thresholds and straightness tolerance thresholds, respectively, and the quality of the IVD syringe under test is judged according to the comparison results. The concentricity tolerance threshold and straightness tolerance threshold are preset according to the design requirements and industry standards of the IVD syringe. If the calculated concentricity or straightness exceeds its corresponding tolerance threshold, the IVD syringe under test is judged to be unqualified; otherwise, it is judged to be qualified.

[0024] This embodiment takes a stainless steel tube with an outer diameter of 1.2 mm, a wall thickness of 0.15 mm, and a total length of 80 mm as an example to illustrate the complete implementation process of the above method.

[0025] Step 1: Obtain the IVD sample dispensing syringe to be tested. In this embodiment, an automated feeding robot arm picks up a single IVD sample dispensing syringe from the vibrating tray and places it vertically on the V-shaped positioning block at the measurement station. The V-shaped positioning block is coaxial with the air-bearing turntable, with a positioning accuracy of ±5μm.

[0026] Step 2: Air Flotation Support and Rotation. The air flotation turntable is activated, and clean compressed air at 0.4 MPa is introduced into its 16 evenly distributed 0.3 mm diameter micro-jet nozzles, forming a uniform air film of approximately 8 μm thickness between the turntable end face and the lower end face of the IVD sample syringe under test. The IVD sample syringe enters a stable suspension state under its own weight and the support of the air film. The coaxiality between the end face and the turntable end face is ensured within ±3 μm by a mechanical alignment mechanism. Subsequently, the permanent magnet synchronous motor integrated with the air flotation turntable is activated, driving the IVD sample syringe to rotate uniformly around its own axis at 600 r / min (i.e., 10 r / s, corresponding to an angular velocity of 62.8 rad / s). After stable rotation, the end face runout is measured using a laser velocimeter and found to be less than 1 μm, confirming that the air flotation support does not introduce additional vibration.

[0027] Step 3: Low-coherence white-light interferometry synchronous scanning. Five sets of low-coherence white-light interferometer probes are evenly arranged along the axis of the IVD sample loading needle, with an axial spacing of 16 mm between adjacent probes, covering the entire axial range of the needle from 0 mm to 80 mm. Each set of probes has four independent sub-probes evenly distributed around the circumference of the needle, arranged at 0°, 90°, 180°, and 270°. The total field of view of a single set of probes is 2.5 mm × 2.5 mm, with an axial resolution of 0.5 μm and a radial resolution of 0.1 μm. The light source is a superluminescent diode (SLD) with a center wavelength of 850 nm and a spectral width of 120 nm, and a coherence length of approximately 6 μm. When the needle rotates at 600 r / min, each set of probes synchronously acquires 3600 frames of interference signals every 0.1 s. After demodulation using a five-step phase-shift algorithm, the instantaneous height map of the outer and inner walls of the needle at the axial position is obtained. All 5×4=20 probes collected data simultaneously, and finally stitched together a 1440×1600 pixel 3D surface point cloud covering the entire circumference and length of the needle tube. The repeatability of single-point height measurement σ=0.05μm.

[0028] Step 4: Coordinate Transformation and 3D Modeling. The point cloud data is transformed into a measurement coordinate system with the center of the lower end face of the IVD sample application tube as the origin and the axis as the Z-axis through a pre-calibrated multi-probe extrinsic matrix. Simultaneously, rotation angle information is recorded, and the sub-point clouds acquired from multiple angles are merged into a unified cylindrical coordinate system according to angle, resulting in a 3D point cloud model with 1440 circles × 1600 rows.

[0029] Step 5: Geometric Feature Recognition and Spatial Axis Determination. The piecewise weighted least squares cylindrical fitting method described herein is employed. The point cloud is divided into 16 segments along the Z-axis, each containing 100 rows of sampling points. Weighted least squares cylindrical fitting is performed on each segment (the weight is the local signal-to-noise ratio σ_SNR of the segment's point cloud; a higher SNR results in a larger weight), yielding 16 local axes. Then, using the spline smoothing transition method described in step 3, the curvature change rate and tangent direction are calculated for the connection points of adjacent local axes (15 connection points at z=5mm, 10mm, 75mm). In this example, the included angle of the tangent direction at all connection points is less than 0.5°, indicating a unidirectional transition. A cubic B-spline function is used to generate a sequence of transition points. The final smoothed 1600-row spatial axis is obtained by minimizing the weighted sum of distance deviation, angle deviation, and curvature deviation.

[0030] Step Six: Concentricity and Straightness Calculation. Take a cross-section every 1 mm along the Z-axis (81 cross-sections in total). Perform least-squares circle fitting on the inner and outer wall point clouds of each cross-section to obtain the inner circle center (x_i, y_i) and outer circle center (x'_i, y'_i). Concentricity is defined as the maximum length of the line connecting the inner and outer circle centers of each cross-section in the longitudinal direction: in this example, the maximum measured value is 6.8 μm. Straightness is defined as the maximum radial deviation of the spatial axis relative to the ideal least-squares fitted straight line: in this example, the maximum radial deviation is 12.3 μm (at z=42 mm).

[0031] Step 7: Quality Judgment. The design requirements for this batch of IVD sample dispensing syringes are concentricity tolerance threshold T_C = 10μm and straightness tolerance threshold T_S = 20μm. The measured concentricity is 6.8μm < 10μm and straightness is 12.3μm < 20μm, both of which are qualified. The system outputs a "qualified" classification result and pushes the dispensing robot arm of this syringe into the qualified material channel. Simultaneously, the measurement results, point cloud data, and judgment timestamp are written into the MES system, forming a single-item product quality traceability record.

[0032] In this embodiment, the complete measurement cycle of a single IVD sample dispensing syringe is 1.8s (including 0.6s for loading and unloading, 0.1s for scanning, 0.4s for calculation, and 0.7s for judging unloading), which meets the production line cycle requirement of 2s / piece. The measurement repeatability was verified by 50 repeated experiments: concentricity σ=0.3μm, straightness σ=0.5μm.

[0033] This application presents a non-contact measurement method for the concentric straightness of IVD sample dispensing needles. By placing the IVD sample dispensing needle under test in an air-bearing support state and rotating it, combined with low-coherence white light interferometry technology, it achieves the acquisition of high-density surface contour information of the needle's entire circumference. This non-contact measurement method fundamentally avoids the microscopic damage to the needle that may be caused by traditional mechanical probes, ensuring the non-destructive nature of the detection process. Through simultaneous scanning across multiple axes and angles, this method can acquire complete three-dimensional spatial data, effectively overcoming the limitations of traditional two-dimensional optical measurements in reconstructing the three-dimensional morphology of the needle, and improving the accuracy and reliability of the measurement data.

[0034] In the data processing stage, this method can accurately identify the geometric features of the syringe and determine its spatial axis, providing a solid foundation for subsequent calculations of concentricity and straightness. Compared with existing technologies that rely on manual sampling or simple two-dimensional measurement, this method can achieve 100% online full inspection of each product and provide real-time, high-precision quality judgment results. This comprehensive inspection capability not only significantly improves production efficiency and yield but also meets the stringent requirements for product quality traceability in the context of intelligent manufacturing. Therefore, this application greatly improves inspection efficiency and reliability while ensuring measurement accuracy, providing advanced technical support for the production quality control of IVD sample dispensing syringes.

[0035] This application further proposes a more refined and robust method for determining spatial axes to improve measurement accuracy and reliability.

[0036] In this regard, refer to Figure 2 , Figure 2 This is a flowchart of a method for determining the spatial axis of the IVD sample dispensing syringe based on the geometric features provided in an embodiment of the present invention. S15 includes: S151, Perform local curvature analysis on the three-dimensional spatial data to identify the curvature variation region along the axial direction on the surface of the IVD sample dispensing syringe to be tested; S152, perform least squares cylindrical fitting on the inner and outer wall sampling points in the curvature change region to obtain the cylindrical surface fitting residual of the IVD sample dispensing syringe to be tested; S153, according to the axial distribution of the fitting residual of the cylindrical surface, the cross section where the residual is greater than the residual threshold is marked as a local geometric anomaly region; S154, the IVD sample dispensing syringe to be tested is divided into multiple sub-regions along the axial direction, and the residual of the sampling point in each sub-region does not exceed the residual threshold. S155, perform weighted least squares cylindrical fitting on the sampling points in each sub-region, with the weight being the local signal-to-noise ratio of the corresponding sampling point, to obtain the local axis of the sub-region; S156, the spatial axis of the IVD sample dispensing syringe is obtained by weighting the local axes of each sub-region according to the local signal-to-noise ratio.

[0037] Specifically, performing local curvature analysis on the three-dimensional spatial data refers to calculating the curvature of each point on the surface of the IVD sample syringe to identify local changes in the surface geometry. For example, differential geometry methods or methods based on fitting surfaces to neighborhood points can be used to calculate the curvature. The purpose is to accurately locate possible depressions, protrusions, edges, or transition regions, which are often where geometric features change significantly.

[0038] The least-squares cylindrical fitting process, which involves selecting measurement points on the inner and outer walls within the identified curvature variation region and fitting an ideal cylindrical surface using the least-squares method, yields the distance from each sampling point to the fitted cylindrical surface—the cylindrical surface fitting residual. This process aims to quantify the deviation of a local region from the ideal cylindrical shape, providing a data foundation for subsequent identification of abnormal regions.

[0039] In practical applications, based on the axial distribution of the fitting residuals of the cylindrical surface, sections with residuals exceeding a residual threshold are marked as local geometric anomaly regions. This means setting a preset residual threshold; when the residual from a sampling point on a certain section to the fitted cylindrical surface exceeds the threshold, the section is considered to have a local geometric anomaly, such as scratches, burrs, or deformation. The purpose is to accurately eliminate or specially treat local defects that may interfere with the overall axial fitting.

[0040] Furthermore, the IVD sample syringe under test is divided into multiple sub-regions along the axial direction. The residual of each sampling point within each sub-region does not exceed the residual threshold. This means that after marking the local geometrically abnormal regions, the remaining portion of the IVD sample syringe (i.e., the non-abnormal region) is divided into several segments along its axial direction. Each sub-region is ensured to have a relatively regular internal geometry without significant local anomalies. The purpose is to provide relatively clean data segments for subsequent local axis fitting.

[0041] Based on this, a weighted least-squares cylindrical fitting is performed on the sampling points within each sub-region, with the weights being the local signal-to-noise ratio (SNR) of the corresponding sampling point, to obtain the local axis of the sub-region. Specifically, the local SNR reflects the reliability of the measurement data; for example, points with a high SNR have higher weights. Through weighted fitting, points with better data quality can contribute more to the determination of the local axis, thereby improving the fitting accuracy of the local axis for each sub-region.

[0042] Finally, the local axes of each sub-region are weighted and averaged according to the local signal-to-noise ratio to obtain the spatial axis of the IVD syringe under test. This means that the local axes fitted from each sub-region are comprehensively considered. Sub-regions with high signal-to-noise ratios are considered to have more reliable local axes and are therefore given higher weights in the weighted averaging. The purpose is to integrate multiple locally reliable axis information to ultimately obtain a robust spatial axis that accurately represents the overall geometric center trend of the entire IVD syringe under test.

[0043] For example, after acquiring the point cloud, it is divided into 8 segments along the needle axis. Each segment is weighted using the local signal-to-noise ratio σ_i as the weight, and a weighted least-squares cylindrical fitting is performed. Sections with residuals greater than the threshold of 0.8 μm are marked as local geometric anomalies and excluded. The fitted axes of the 8 segments are weighted and averaged according to σ_i, and then the transition points are connected by cubic B-splines to obtain the final spatial axis. Results: The concentricity of a certain needle was measured to be 6.5 μm, which is 17% more accurate than the overall fitting result of 7.8 μm without this method.

[0044] This application's solution, by introducing a multi-stage, refined data processing workflow, effectively solves the problem of insufficient accuracy in determining the spatial axis when traditional methods handle IVD sample dispensing syringes with local defects or geometric irregularities. Through the above technical solution, this application can significantly improve the accuracy and robustness of determining the spatial axis of IVD sample dispensing syringes.

[0045] In some preferred embodiments, a specific example is illustrated below. Suppose an IVD sample syringe has a small dent in its middle. In conventional global fitting methods, this dent might be averaged, causing a slight shift in the overall axis towards the dent. Using the solution of this application, firstly, by performing local curvature analysis on the three-dimensional spatial data of the syringe, the curvature change in the dent region is identified. Next, least-squares cylindrical fitting is performed on the sampling points of the inner and outer walls within the curvature change region to calculate the cylindrical surface fitting residual of the dent region. Due to the presence of the dent, the residual in this region will be significantly greater than a preset residual threshold; therefore, this section is marked as a local geometric anomaly region. Subsequently, the remaining part of the syringe (i.e., the region outside the dent) is divided into multiple sub-regions, where the residual of the sampling points in each sub-region does not exceed the residual threshold. Weighted least-squares cylindrical fitting is performed on these anomaly-free sub-regions, and their respective local axes are obtained based on the local signal-to-noise ratio of each sub-region. Since the dent region is identified and isolated, its impact on the local axis fitting is minimized. Finally, by weighting these local axes according to their local signal-to-noise ratio, a more accurate spatial axis that is not significantly affected by the indentation can be obtained. For example, if the data quality of the head and tail of the syringe is high, their local axes will account for a larger proportion in the weighted average, thus ensuring that the final spatial axis can more realistically reflect the overall geometric center of the syringe, and guaranteeing measurement accuracy even with local defects.

[0046] This application further proposes the following steps for obtaining the spatial axis of the IVD sample dispensing syringe by weighting the local axes of each sub-region according to the local signal-to-noise ratio: For the connection region between two adjacent local axes, the rate of curvature change and tangent direction are calculated to obtain the transition type of the connection region. The transition type includes unidirectional transition, angled transition, and misaligned transition. Select the corresponding spline smoothing function according to the transition type; Calculate the distance deviation, angle deviation, and curvature deviation of the two adjacent local axes at the connection point; A sequence of transition points is generated in the connection region according to the selected spline smoothing function, and the spatial position of each transition point in the sequence of transition points is adjusted to minimize the weighted sum of the distance deviation, the angle deviation, and the curvature deviation. The adjusted transition point sequence is connected to the unadjusted local axis segment to obtain the spatial axis of the IVD sample dispensing syringe to be tested.

[0047] Specifically, the rate of curvature change and tangent direction are calculated for the connecting region between two adjacent local axes. The purpose is to accurately identify the geometric characteristics of these local axes at the connection point. Analyzing the rate of curvature change determines the degree of axis bending, while the tangent direction reflects the local orientation of the axis. Based on these calculations, the transition type of the connecting region can be determined. For example, when adjacent axes have essentially the same direction and the curvature change is gradual, it can be identified as a unidirectional transition; when there is a significant deflection in the axis direction, it can be identified as an angled transition; and when there is radial displacement of the axis at the connection point, it can be identified as a misaligned transition.

[0048] Selecting the corresponding spline smoothing function according to the transition type refers to choosing the most suitable mathematical spline function for the transition characteristics based on the identified transition types, such as unidirectional transitions, angled transitions, or misaligned transitions. For example, for unidirectional transitions, cubic splines or B-splines can be selected to maintain smoothness; for angled transitions, splines with local control capabilities may be needed to allow for large directional changes at specific points; for misaligned transitions, it may be necessary to consider introducing additional constraints at the connection or using more complex spline forms to bridge the displacements. The aim is to ensure that the selected function can accurately and smoothly connect adjacent local axes while respecting their inherent geometric characteristics.

[0049] In practical applications, calculating the distance, angle, and curvature deviations at the connection points of two adjacent local axes aims to quantify the degree of discontinuity in the connection region. Distance deviation measures the spatial difference between the two axes at the connection point; angle deviation measures the directional difference; and curvature deviation measures the difference in the degree of curvature. These deviation values ​​serve as inputs to the subsequent optimization process, guiding the adjustment of the transition point sequence.

[0050] Furthermore, a sequence of transition points is generated in the connected region according to the selected spline smoothing function, and the spatial positions of each transition point in the sequence are adjusted to minimize the weighted sum of the distance deviation, the angle deviation, and the curvature deviation. This means that, based on the selected spline function, the coordinates of the transition point sequence are fine-tuned through an iterative optimization algorithm to minimize the geometric discontinuities at the connection points while satisfying smoothness. Minimizing the weighted sum ensures that the optimal transition path is found by comprehensively considering multiple deviations.

[0051] Therefore, the adjusted transition point sequence is connected to the unadjusted local axis segment to obtain the spatial axis of the IVD sample dispensing syringe under test. This process ensures that the final spatial axis not only maintains high accuracy within each sub-region, but also achieves high smoothness and geometric continuity at the connections between sub-regions.

[0052] For example, among the eight axis segments, the geometric transition types of connection points 1 to 7 are identified. At connection point 3, the tangent direction deflects by 2.1°, which is identified as a "bent transition," and a B-spline function with local control capability is selected. The positions of the connection point sequence are adjusted to minimize the weighted sum of distance deviation (weight 0.4), angle deviation (weight 0.3), and curvature deviation (weight 0.3). After processing, the axis curvature discontinuity at this point decreases from 0.15 rad / mm to 0.02 rad / mm.

[0053] This application's solution effectively solves the problems of axis discontinuity and unevenness that may result from simple weighted averaging by introducing refined processing of the connection region between adjacent local axes. Through the above technical solution, this application can significantly improve the accuracy and robustness of determining the spatial axis of the IVD sample loading syringe. Compared to methods that only perform local axis weighted averaging, this solution, by refining the analysis of the geometric characteristics of the connection region and selecting a suitable spline smoothing function, effectively avoids the problems of axis discontinuity, local distortion, or insufficient smoothing that may result from simple averaging.

[0054] In some preferred embodiments, it is assumed that the IVD sample application syringe to be tested is divided into three sub-regions, resulting in three local axes L1, L2, and L3. A smooth connection of the spatial axes is required between connecting region 1 (between L1 and L2) and connecting region 2 (between L2 and L3).

[0055] Specifically, in connection region 1, the system first calculates the rate of curvature change and tangent direction. If the tangent directions of L1 and L2 are found to be basically consistent and the curvature change is gradual, it is identified as a "same-direction transition" type. At this time, the system selects a cubic spline function as the smoothing function. Subsequently, the distance deviation, angle deviation, and curvature deviation of L1 and L2 at the connection point are calculated. Based on the selected cubic spline function, a series of transition point sequences are generated in connection region 1, and the spatial positions of these transition point sequences are adjusted through an optimization algorithm to minimize the weighted sum of distance deviation, angle deviation, and curvature deviation.

[0056] In connection region 2, if the calculation results show a significant deflection angle in the tangent directions of L2 and L3, it is identified as a "bent transition" type. For this type, the system may choose a B-spline function with local control capabilities to allow for a relatively sharp but smooth transition at the connection point. Similarly, the deviations of L2 and L3 at the connection point are calculated, and the transition point sequence is adjusted to minimize the weighted sum.

[0057] Finally, by connecting the adjusted transition point sequence with the unadjusted local axis segments L1, L2, and L3, a highly smooth and accurate spatial axis of the IVD syringe under test is obtained globally. In this way, even if the IVD syringe has complex geometric variations, its spatial axis can be accurately and continuously characterized.

[0058] In some embodiments described above in this application, by converting surface contour information into three-dimensional spatial data and processing it, the geometric features of the IVD sample syringe under test can be identified, and its spatial axis can be determined based on these features. However, in actual measurement, due to the possibility of minor defects, local contamination, or random noise in the measurement environment on the surface of the IVD sample syringe under test, the initially acquired surface contour information may contain a certain degree of abnormal data points. If these abnormal points are not effectively identified and processed, they may interfere with the accuracy of determining the spatial axis, thereby affecting the accuracy of the final concentricity and straightness calculations. If the above problems are not solved, it may lead to deviations in the quality judgment of the IVD sample syringe, affecting the reliability of the product. To address this, this application further proposes a method for optimizing data processing and scanning strategies, aiming to improve the accuracy and reliability of measurement results through iterative optimization and data fusion.

[0059] In response, this application further proposes that after processing the three-dimensional spatial data, identifying the geometric features of the IVD sample dispensing syringe under test, and determining the spatial axis of the IVD sample dispensing syringe under test based on the geometric features, the application also includes: According to the spatial axis, measurement points whose distance deviation from the spatial axis exceeds the first preset threshold are marked as first-type abnormal points; Measurement points whose distance deviation from the spatial axis does not exceed the second preset threshold and are not marked as first-type anomalies are marked as valid measurement points, wherein the second preset threshold is less than the first preset threshold; The first type of outliers are removed from the three-dimensional spatial data, and the spatial axis is recalculated based on the remaining valid measurement points to obtain the updated spatial axis. The IVD sample syringe under test was scanned a second time using a low-coherence white light interferometry method. The scanning resolution and scanning field of view were adjusted according to the updated spatial axis to obtain the second round of surface contour information. The first round of surface contour information and the second round of surface contour information are fused according to the coordinate registration result to obtain the fused surface contour information; The three-dimensional spatial data corresponding to the fused surface contour information is used as the data basis for the final calculation of concentricity and straightness.

[0060] Specifically, after initially determining the spatial axis of the IVD sample dispensing syringe to be tested, the acquired three-dimensional spatial data is first subjected to anomaly identification. Measurement points whose distance deviation from the spatial axis exceeds a first preset threshold are identified and marked as first-type anomalies. The first preset threshold can be set based on factors such as the typical size of the IVD sample dispensing syringe, material properties, and allowable surface roughness; for example, it can be set to 0.5% or 1% of the syringe diameter. These first-type anomalies typically represent significant surface defects, measurement noise peaks, or data acquisition errors. Simultaneously, measurement points whose distance deviation from the spatial axis does not exceed a second preset threshold and are not marked as first-type anomalies are marked as valid measurement points. The second preset threshold is usually lower than the first preset threshold, its purpose being to define a stricter range and ensure the high reliability of the data marked as valid measurement points. For example, the second preset threshold can be set to half of the first preset threshold. Furthermore, after identifying the first-type anomalies, these anomalies are removed from the original three-dimensional spatial data. Based on the remaining valid measurement points, the system will re-execute the spatial axis calculation process, for example, by using methods such as least squares cylindrical fitting again, to obtain a more accurate and robust updated spatial axis.

[0061] Building upon this foundation, to further enhance measurement accuracy, a second scan of the IVD sample loading needle is performed using low-coherence white light interferometry. This scan adaptively adjusts the scanning resolution and field of view based on the updated spatial axis. For example, for areas where subtle geometric changes or potential anomalies were detected in the first scan, the local scanning resolution can be increased; for areas with good data quality and stable geometric features, the resolution can be appropriately reduced to improve efficiency. Adjusting the scanning field of view ensures more comprehensive data coverage in critical areas. In this way, more refined and accurate second-round surface profile information can be obtained.

[0062] Subsequently, the surface contour information from the first and second rounds is fused. This fusion process is based on precise coordinate registration, ensuring spatial alignment between the two rounds of data. The fused surface contour information combines the advantages of both scans, including the overall coverage of the first scan and incorporating the detailed data from the second scan in key areas, thus forming a more complete, accurate, and outlier-free 3D spatial data. Finally, the 3D spatial data corresponding to the fused surface contour information is used as the basis for calculating the concentricity and straightness of the IVD sample loading syringe under test, ensuring the reliability and high accuracy of the final measurement results.

[0063] The proposed solution effectively addresses the problem of outliers in the initial measurement data interfering with the accuracy of spatial axis determination by introducing iterative optimization and data fusion mechanisms. By adjusting the scanning resolution and scanning field of view, more precise measurements can be performed on key areas, compensating for potential local data deficiencies or insufficient accuracy in the first round of scanning.

[0064] In some preferred embodiments, a specific example is given below. Assume that after the initial low-coherence white light interferometry scan, the surface contour information of the IVD sample loading syringe under test is acquired and converted into three-dimensional spatial data. Through preliminary processing, an initial spatial axis is determined. At this point, the system calculates the distance deviation of each measurement point from the initial spatial axis. For example, a first preset threshold is set to 5 micrometers, and a second preset threshold is set to 2 micrometers. If the distance deviation of a measurement point from the axis exceeds 5 micrometers, it is marked as a first-type anomaly; for example, this could be a surface scratch or a tiny bump. If the distance deviation of a measurement point from the axis is within 2 micrometers and it is not marked as a first-type anomaly, it is marked as a valid measurement point.

[0065] Subsequently, all measurement data marked as Category I outliers are removed from the 3D spatial dataset. Based on the remaining valid measurement points, the system re-performs least-squares cylinder fitting to obtain a corrected, updated spatial axis. This updated spatial axis will more accurately reflect the true geometric center of the needle.

[0066] Next, the system will initiate a second round of low-coherence white-light interferometric scanning. In this second round, the system will adjust the scanning parameters based on the updated spatial axes. For example, if the distance deviation in a certain region, found in the first round, is close to a second preset threshold but not exceeding a first preset threshold, indicating potential minor geometric irregularities in that region, the axial and circumferential scanning resolution of that region will be doubled in the second round to obtain denser measurement points. Simultaneously, the scanning field of view will be fine-tuned to ensure comprehensive coverage of the region.

[0067] After the second round of scanning, second-round surface contour information will be obtained. The system will use a high-precision registration algorithm to spatially align and fuse the surface contour information from the first and second rounds. The fused data will contain the overall overview of the first round of scanning and the fine details of the second round of scanning in key areas, and will have eliminated significant outliers from the first round. Finally, based on this fused, high-precision, outlier-free 3D spatial data, the concentricity and straightness of the IVD sample loading syringe will be calculated, thereby obtaining more reliable and accurate quality assessment results.

[0068] This application proposes a more refined quality assessment method. By dividing the IVD sample dispensing syringe into regions and setting differentiated judgment rules and tolerance thresholds for different regions, a more accurate quality assessment that better meets the needs of practical applications can be achieved.

[0069] The step of comparing the concentricity and straightness with the corresponding concentricity tolerance threshold and straightness tolerance threshold, respectively, and judging the quality of the IVD sample dispensing syringe to be tested based on the comparison results includes: The spatial axis is divided into regions to identify characteristic areas on the IVD sample dispensing syringe where the material response characteristics differ from the substrate or where the surface is covered with a functional coating; Obtain the material properties or coating optical parameters of the feature region; According to the material property parameters or the coating optical parameters, a local reference axis definition rule and a local tolerance threshold are set for the feature region. The local tolerance threshold is different from the default tolerance threshold used in the region outside the feature region. Calculate the local concentricity and local straightness of the feature region according to the local reference axis definition rules; The measurement results of the feature region are judged using the local tolerance threshold, and the measurement results of the region outside the feature region are judged using the default tolerance threshold. By integrating the quality assessment results of the characteristic region with those of the region outside the characteristic region, the overall quality assessment of the IVD sample dispensing syringe to be tested is obtained.

[0070] Specifically, dividing the spatial axis into regions and identifying characteristic areas on the IVD sample application syringe where the material response characteristics differ from the substrate or where the surface is covered with a functional coating involves analyzing the syringe's physical or chemical properties, such as material composition, surface roughness, and optical reflection / transmission characteristics, to determine its different functional or structural regions along the axial direction. These characteristic regions may include the needle tip, needle body, and connecting parts, which may be made of different materials or have special functional layers coated on their surfaces.

[0071] Obtaining the material properties or coating optical parameters of the feature region can be understood as scanning the identified feature region with a non-contact sensor (such as a spectrometer or infrared sensor) to obtain its unique physical or optical fingerprint. For example, for a region with a hydrophobic coating, its specific spectral absorption or reflection curve can be obtained; for regions with different metal alloys, their elemental composition information can be obtained. These parameters form the basis for subsequently setting local judgment rules.

[0072] In practical applications, defining local reference axes and setting local tolerance thresholds for feature regions based on material property parameters or coating optical parameters refers to customizing the evaluation criteria for concentricity and straightness according to the specific function and material properties of each feature region. For example, for a needle tip region requiring high-precision liquid aspiration, its concentricity tolerance threshold may be much smaller than that of the needle body region; for a coating region with specific optical functions, its straightness tolerance threshold may need to consider the uniformity of the coating thickness. The local tolerance threshold differs from the default tolerance threshold used for areas outside the feature region, ensuring the specificity and accuracy of the evaluation.

[0073] Furthermore, calculating the local concentricity and local straightness of a feature region according to the local reference axis definition rules means that within each divided feature region, a corresponding reference axis calculation method is redefined or applied based on the specific requirements of the region, and the concentricity and straightness of the region are calculated accordingly. For example, for a curved feature region, its local reference axis may be a fitted curve rather than a simple straight line.

[0074] Therefore, a local tolerance threshold is used to judge the quality of measurement results in the characteristic area, while a default tolerance threshold is used to judge the quality of measurement results in areas outside the characteristic area, thus achieving regional and differentiated quality assessment. This means that each area is judged independently based on its own function and design requirements, avoiding a "one-size-fits-all" evaluation method.

[0075] Finally, the quality judgment results of the characteristic region and the region outside the characteristic region are integrated to obtain the overall quality assessment of the IVD sample dispensing syringe to be tested, which ensures a comprehensive evaluation of the entire syringe while taking into account the special characteristics of each part.

[0076] For example, a 0-3mm section of the needle tip is coated with a hydrophobic coating. After identifying the characteristic region using spectral imaging, a local concentricity tolerance T_C_local is set to 5μm (the needle body's default T_C_default is 10μm). The measured local concentricity of this section is 3.2μm < 5μm, which is considered acceptable. While a uniform T_C_default would also be acceptable, this method more accurately reflects the actual functional requirements of the needle tip.

[0077] The solution proposed in this application introduces a mechanism for dividing the spatial axis of the IVD sample dispensing syringe into regions, and sets differentiated local reference axis definition rules and local tolerance thresholds for different regions based on their material response characteristics or surface coating characteristics. This solves the problem of inaccurate or incomplete evaluation caused by using a single global tolerance threshold for quality judgment in traditional methods.

[0078] In some preferred embodiments, an IVD sample dispensing syringe is assumed to have a tip region made of a special alloy with a hydrophobic coating, while the main body is constructed of a stainless steel substrate. For quality assessment, the spatial axis of the IVD sample dispensing syringe is first divided into regions, identifying the tip region as the characteristic region and the main body as the non-characteristic region. Next, the optical parameters of the coating on the tip region are acquired using non-contact spectral imaging, such as its reflectance and absorptivity curves at specific wavelengths, as well as the material properties of the tip alloy. Based on these parameters, a more stringent local concentricity tolerance threshold and local straightness tolerance threshold are set for the tip region than for the main body region, and different local reference axis definition rules may be employed (e.g., the tip portion may focus more on the concentricity of its very tip).

[0079] Subsequently, the local concentricity and straightness of the needle tip area are calculated separately and compared with the set local tolerance thresholds. Simultaneously, the concentricity and straightness of the needle body body area are compared with the default global tolerance thresholds. Finally, the quality judgment results of the needle tip area and the needle body body area are integrated. For example, if the needle tip area is substandard, the entire needle tube is judged as substandard, even if the needle body body is qualified; if all areas are qualified, the entire needle tube is judged as qualified. This method ensures strict quality control of the needle tube's critical functional areas while maintaining reasonable evaluation standards for non-critical areas, thereby achieving comprehensive and accurate quality assessment.

[0080] In some embodiments described above, this application proposes dividing the spatial axis of the IVD sample dispensing syringe into regions to identify characteristic areas where the material response characteristics differ from the substrate or where the surface is covered with a functional coating. Local tolerance thresholds are then set for these regions to determine quality. However, in its implementation, if the identification of characteristic regions relies on human experience or simple geometric features, it may lead to insufficient identification accuracy, low efficiency, or even an inability to accurately distinguish subtle differences in materials or coatings, thereby affecting the reliability of the final quality assessment.

[0081] In response, this application further proposes a step for dividing the aforementioned spatial axis into regions and identifying characteristic regions on the IVD sample dispensing syringe where the material response characteristics differ from the substrate or where the surface is covered with a functional coating, including: A non-contact spectral imaging method was used to acquire surface spectral response data at different wavelengths along the axis of the IVD sample dispensing needle under test. Based on the axial distribution of surface spectral response data, identify differences in material response or optical differences in coatings; By combining the local curvature distribution and geometric feature changes of the IVD sample dispensing syringe under test, the starting and ending positions of material response differences or surface functional coating areas can be determined. The feature regions are divided according to the start and end positions.

[0082] Specifically, non-contact spectral imaging refers to illuminating the surface of the IVD sample syringe under test with a light beam of a specific wavelength and receiving the reflected or transmitted spectral signals to analyze the chemical composition, crystal structure, or coating characteristics of the surface material. This method avoids physical contact with the IVD sample syringe under test, ensuring the non-destructive nature of the measurement. Acquiring surface spectral response data at different wavelengths along the axis of the IVD sample syringe under test involves continuously or discretely collecting the surface light response intensity within multiple preset wavelength ranges using a spectrometer while the IVD sample syringe rotates or scans along its axis. These data can reflect the unique spectral fingerprints of different materials or coatings at different wavelengths.

[0083] Identifying material response differences or coating optical differences based on the axial distribution of surface spectral response data can be understood as detecting discontinuities or changes in material composition or surface coatings along the axial direction by analyzing the trends in spectral intensity, peak position, and full width at half maximum (FWHM) along the axis of the IVD sample application needle. For example, different materials or coatings exhibit different absorption, reflection, or scattering characteristics at specific wavelengths, and these differences will form obvious features in the spectral data.

[0084] In practical applications, determining the start and end positions of material response differences or functional coating regions by combining the local curvature distribution and geometric feature changes of the IVD sample dispensing syringe under test involves further utilizing the geometric information of the IVD sample dispensing syringe (such as diameter changes, taper, chamfers, etc.) to precisely define the boundaries of characteristic regions after identifying spectral response differences. For example, some functional coatings may only cover areas with specific geometric shapes; by combining geometric features, spectral noise in non-coated areas can be avoided from being misjudged as characteristic regions. Finally, the characteristic regions are divided according to the start and end positions. That is, based on the precise boundaries determined above, the overall spatial axis of the IVD sample dispensing syringe under test is divided into multiple sub-regions with different material or coating properties, so that local tolerance thresholds can be applied subsequently in a targeted manner.

[0085] For example, a UV-VIS-NIR spectrometer was used to scan along the needle axis to obtain the reflectance spectrum in the range of 200 nm to 1100 nm. The reflectance of the needle tip coating area drops sharply by 12% at 620 nm. Combined with the geometric feature of the diameter shrinking by 0.08 mm in the region, the coating start position z=0.3 mm and the end position z=3.1 mm were accurately located, with a feature area division accuracy of ±0.05 mm.

[0086] This application's solution, by introducing non-contact spectral imaging technology, can objectively and quantitatively acquire axial material and coating information on the surface of the IVD sample syringe under test. Through the above technical solution, this application can achieve high-precision, non-contact, and automated identification and segmentation of characteristic regions with special materials or functional coatings on the IVD sample syringe.

[0087] Specifically, in the process of identifying the characteristic regions on the IVD sample dispensing syringe where the material response characteristics differ from the substrate or where the surface is covered with a functional coating, a non-contact spectral imaging method is used to acquire surface spectral response data at different wavelengths along the axis of the IVD sample dispensing syringe. The specific implementation method is as follows: The method employs non-contact spectral imaging to acquire surface spectral response data at different wavelengths along the axial direction of the IVD sample dispensing needle under test, including: Based on the surface reflection and light transmission characteristics of the IVD sample dispensing syringe to be tested, select the wavelength range and light source intensity; When the reflectivity of the IVD sample syringe surface under test is higher than the reflectivity threshold, a high-angle incident and low-angle received optical path configuration is adopted, and polarized light technology is combined to obtain the diffuse reflectance spectrum signal of the IVD sample syringe surface under test. When the surface of the IVD sample syringe under test is transparent, multiple wavelengths with different penetration depths are selected for scanning, and the focusing depth and detector gain are adjusted at each wavelength to obtain spectral information of the IVD sample syringe at different depth levels. The spectral signal at each wavelength is sampled multiple times and the average value is taken to obtain the denoised spectral data. The light source intensity and detector response are calibrated before each scan to obtain the calibrated spectral data.

[0088] Specifically, selecting the wavelength range and light source intensity based on the surface reflectance and transmittance characteristics of the IVD sample dispensing syringe under test refers to pre-evaluating the syringe's reflection, absorption, and transmission capabilities for different wavelengths of light, based on its material composition and surface treatment. For example, for metallic syringes, wavelengths with high reflectivity in the visible or near-infrared bands may be selected; for plastic or glass syringes, wavelengths capable of penetrating the material and detecting internal structural information may be necessary. The light source intensity is then adjusted according to the selected wavelength range and material characteristics to ensure the detector receives a sufficient but not oversaturated signal.

[0089] In this study, when the reflectivity of the IVD sample dispensing syringe surface exceeds a reflectivity threshold, a high-angle incident and low-angle received optical path configuration is employed, combined with polarized light technology, to acquire the diffuse reflectance spectral signal of the IVD sample dispensing syringe surface. This high-angle incident and low-angle received optical path configuration aims to suppress specular reflection to the greatest extent possible, thereby highlighting the diffuse reflectance signal. The diffuse reflectance signal carries more information about the microstructure and chemical composition of the material surface. Combining polarized light technology further separates surface reflection and volume scattering signals, improving the accuracy of material property identification.

[0090] In practical applications, when the surface of the IVD sample dispensing syringe under test is transparent, multiple wavelengths with different penetration depths are selected for scanning. The focusing depth and detector gain are adjusted at each wavelength to obtain spectral information at different depth levels of the IVD sample dispensing syringe. For transparent materials, different wavelengths of light have different penetration depths. By selecting multiple wavelengths with different penetration depths for scanning and precisely adjusting the focusing depth of the optical system, spectral information at different depth levels within the material can be detected. Simultaneously, adjusting the detector gain ensures high-quality spectral signals are obtained at different depths and wavelengths.

[0091] Furthermore, the spectral signal at each wavelength is sampled multiple times and averaged to obtain denoised spectral data. Multiple sampling and averaging is an effective denoising method that can significantly improve the signal-to-noise ratio of spectral data, reduce the impact of random noise on measurement results, and thus improve data reliability. Before each scan, the light source intensity and detector response are calibrated to obtain calibrated spectral data. This aims to eliminate measurement errors caused by equipment drift and environmental changes, ensuring the accuracy and comparability of each measurement result.

[0092] This application's solution adaptively adjusts spectral imaging parameters and optical path configuration based on the surface optical properties (reflection or transmission) of the IVD sample application needle under test, effectively acquiring high-quality surface spectral response data. For highly reflective surfaces, by optimizing the incident / receiver angle and polarization techniques, strong specular reflection can be effectively suppressed, highlighting diffuse reflection signals carrying material characteristic information. For transparent surfaces, multi-wavelength, multi-focus depth scanning enables spectral detection at different depths within the material. These refined data acquisition strategies, combined with multiple sampling noise reduction and system calibration, ensure the accuracy, reliability, and comprehensiveness of the acquired spectral data, providing a solid data foundation for subsequent feature region identification.

[0093] Specifically, the above-mentioned low-coherence white light interferometry method, which simultaneously scans from multiple axial positions and multiple angles around the axis of the IVD sample syringe under test, to obtain surface contour information covering the entire circumference of the IVD sample syringe under test, may include the following steps: At multiple axial positions of the IVD sample dispensing needle under test, multiple sets of interference probes distributed around the axis of the IVD sample dispensing needle under test synchronously acquire interference signals from multiple angles surrounding the axis of the IVD sample dispensing needle under test. The complete surface profile of the IVD sample dispensing syringe under test is reconstructed based on the interference signals at each of the stated axial positions and angles.

[0094] Here, "multiple interferometric probes" refers to multiple independent low-coherence white-light interferometry units strategically arranged around the axis of the IVD sample application needle under test to ensure that the needle surface can be measured from different angles. These probes can be fiber optic probes or free-space optical probes, and their number and distribution density can be adjusted according to the required measurement accuracy and the geometric complexity of the needle. For example, three, four, or more probes can be evenly distributed along the circumference to achieve full coverage of the needle's circumference without blind spots.

[0095] "Synchronous acquisition of interference signals" refers to the process where, during the rotation of the IVD sample application needle, each interference probe acquires interference signals in its respective field of view in parallel at the same moment or within a very short time interval. This synchronous acquisition mechanism ensures that consistent and correlated surface information can be obtained at specific rotation angles and axial positions, avoiding measurement errors caused by time asynchrony.

[0096] "Reconstructing the complete surface profile of the IVD sample loading needle under test" refers to reconstructing the three-dimensional surface morphology of the IVD sample loading needle under test by using signal processing and data fusion algorithms from interference signals acquired from multiple axial positions and multiple angles. This typically involves phase demodulation and height mapping of the interference signals, and coordinate transformation and stitching of data from different probes and scanning positions to ultimately generate a high-precision, full-circumference three-dimensional point cloud or mesh model, thereby completely characterizing the surface profile of the needle.

[0097] This application's solution overcomes the occlusion and measurement blind spots that may exist when acquiring the surface profile of complex geometries or high aspect ratio structures by deploying multiple sets of interferometric probes at multiple axial positions and simultaneously acquiring interferometric signals from multiple angles surrounding the axis of the IVD sample loading needle under test. Synchronous acquisition ensures that measurement data from different perspectives remain consistent over time during needle rotation, providing a reliable data foundation for subsequent accurate 3D reconstruction. Subsequently, by comprehensively processing and reconstructing these multi-angle, multi-axial interferometric signals, a high-precision surface profile information covering the entire circumference of the IVD sample loading needle under test can be generated, providing comprehensive and accurate geometric data for subsequent concentricity and straightness calculations.

[0098] In some embodiments described above, the quality assessment of IVD dispensing syringes is primarily accomplished by comparing concentricity and straightness with their respective tolerance thresholds. However, in practical applications, threshold judgments based solely on a single parameter may not fully reflect the overall dispensing accuracy and functional performance of the IVD dispensing syringe, especially when fine-grained grading or comprehensive performance evaluation of the syringe is required. This simple approach has limitations. For example, even when concentricity and straightness are both within their respective tolerances, their combined effect may lead to poor dispensing accuracy; or, when a parameter slightly exceeds the tolerance but its impact on overall dispensing accuracy is negligible, a simple "unqualified" judgment may be too arbitrary. Therefore, this application further proposes a more comprehensive and refined quality assessment method by introducing dispensing accuracy evaluation values ​​and quality grade classifications to provide more instructive quality assessment results.

[0099] The above-mentioned steps for quality assessment of the IVD sample dispensing syringe to be tested specifically include: The sampling accuracy evaluation value of the IVD sample dispensing syringe to be tested is calculated by weighting the concentricity and straightness according to the preset weights. The quality grade of the IVD sample dispensing syringe is determined by matching the sample dispensing accuracy assessment value with the grade threshold range. The quality grade includes qualified, critical, and unqualified. Output the classification result corresponding to the quality level.

[0100] Specifically, the sample dispensing accuracy assessment value refers to a quantitative indicator that comprehensively reflects the overall performance of the IVD dispensing syringe. It is calculated by weighting and summing the obtained concentricity and straightness data according to preset weights, or by using other mathematical models for comprehensive calculation. The preset weights are coefficients determined based on the relative importance of concentricity and straightness to the final dispensing accuracy during actual sample dispensing. For example, in some application scenarios, concentricity may have a greater impact on dispensing accuracy, and its weight will be increased accordingly. These weights can be set based on experimental data, simulation analysis, or industry standards.

[0101] Furthermore, the grade threshold intervals refer to multiple pre-defined intervals used to divide the range of sample dispensing accuracy assessment values. Each interval corresponds to a specific quality grade. For example, one assessment value range can be set as "qualified," another as "critical," and a third as "unqualified." By matching the calculated sample dispensing accuracy assessment values ​​with these grade threshold intervals, the quality grade of the IVD dispensing syringe to be tested can be determined. "Qualified" indicates that the syringe fully meets all performance requirements and can be used directly; "critical" indicates that the syringe performance is on the edge of the acceptable range and may require further verification or is only suitable for specific applications with low requirements; "unqualified" indicates that the syringe performance does not meet the basic requirements and is not suitable for use. Finally, the system will output the classification results corresponding to the determined quality grade, providing clear guidance for subsequent production, quality inspection, and application.

[0102] This application's solution overcomes the limitations of traditional single-parameter threshold judgment by introducing a weighted calculation of the dispensing accuracy evaluation value. Through this technical solution, this application provides a more comprehensive, refined, and instructive method for judging the quality of IVD dispensing syringes. Compared to methods relying solely on a single parameter threshold, this solution, by weighting the dispensing accuracy evaluation value, can more accurately reflect the combined impact of concentricity and straightness on overall dispensing accuracy, thus avoiding misjudgments caused by fluctuations in local parameters. Furthermore, the introduction of multi-level quality classification means that the quality evaluation result is no longer a simple pass / fail, but provides more detailed classifications such as "qualified," "critical," and "unqualified." This helps users make more reasonable selections and uses of IVD dispensing syringes according to different application scenarios and accuracy requirements. Therefore, this not only improves the scientific rigor and accuracy of quality judgment but also provides a more flexible and efficient means for quality control and product grading in the production process, ultimately contributing to improving the overall quality and market competitiveness of IVD dispensing syringes.

[0103] In some preferred embodiments, a specific example is given below. Suppose a batch of IVD syringes is being measured, and the concentricity measurement of one IVD syringe is 0.02 mm, and the straightness measurement is 0.03 mm. Based on practical application requirements and experience, the weight of concentricity is set to 0.6, and the weight of straightness is set to 0.4.

[0104] First, the sample dispensing accuracy assessment value of the IVD sample dispensing syringe to be tested is calculated according to preset weights. For example, a linear weighted model can be used: Sample addition accuracy assessment value = (concentricity measurement value × concentricity weight) + (straightness measurement value × straightness weight); The estimated value of the sample addition accuracy is: (0.02mm × 0.6) + (0.03mm × 0.4) = 0.012mm + 0.012mm = 0.024mm.

[0105] Next, the calculated sampling accuracy assessment value of 0.024 mm is matched with the preset grade threshold range. Assume the preset grade threshold range is as follows: Acceptable: Sample addition accuracy assessment value ≤ 0.025mm Critical threshold: 0.025mm < sample loading accuracy assessment value ≤ 0.035mm Unacceptable: Sample loading accuracy assessment value > 0.035mm Since the calculated sampling accuracy assessment value of 0.024 mm is less than or equal to 0.025 mm, the IVD sampling syringe to be tested is determined to be of "qualified" quality grade. Finally, the system will output a "qualified" classification result. In this way, even if concentricity or straightness individually approaches its upper tolerance limit, as long as its overall assessment value is within the "qualified" range, it can still be judged as qualified, thus avoiding excessive scrap due to minor deviations in a single parameter, and improving production efficiency and resource utilization.

[0106] refer to Figure 3 , Figure 3 This is a schematic diagram of a non-contact measurement system for the concentricity straightness of an IVD sample dispensing syringe provided in an embodiment of the present invention, comprising: The rotating support module is used to acquire the IVD sample dispensing needle to be tested, place the IVD sample dispensing needle to be tested in an air-float support state, and control the IVD sample dispensing needle to be tested to rotate around the axis at a preset angular velocity. The optical scanning module is used to scan the IVD sample tube under test, which is in the air-supported state and rotating around the axis of the IVD sample tube under test at the preset angular velocity, simultaneously from multiple axial positions and multiple angles around the axis of the IVD sample tube under test in a low-coherence white light interferometry method, to obtain surface contour information covering the entire circumference of the IVD sample tube under test. The data processing module is used to receive the surface contour information, convert the surface contour information into three-dimensional spatial data, establish a measurement coordinate system fixed to the IVD sample dispensing needle under test, process the three-dimensional spatial data to identify the geometric features of the IVD sample dispensing needle under test, and determine the spatial axis of the IVD sample dispensing needle under test according to the geometric features. The calculation and judgment module is used to calculate the concentricity and straightness of the IVD sample dispensing syringe to be tested according to the spatial axis, compare the concentricity and straightness with the corresponding concentricity tolerance threshold and straightness tolerance threshold respectively, and judge the quality of the IVD sample dispensing syringe to be tested according to the comparison results.

[0107] This application also discloses a non-contact measurement system for the concentricity and straightness of IVD sample dispensing needles. The system integrates a rotation support module, an optical scanning module, a data processing module, and a calculation and judgment module to achieve high-precision, non-destructive, full-size measurement and quality assessment of the concentricity and straightness of IVD sample dispensing needles. The rotation support module ensures that the IVD sample dispensing needle under test is measured in a non-contact, stable rotating state, avoiding damage that may be caused by traditional contact measurements. The optical scanning module utilizes low-coherence white light interferometry to simultaneously acquire surface contour information of the needle from multiple dimensions, overcoming the limitations of traditional two-dimensional optical measurements in three-dimensional morphology reconstruction. The data processing module converts the acquired contour information into three-dimensional spatial data and accurately identifies geometric features to determine the spatial axis of the needle. Finally, the calculation and judgment module calculates the concentricity and straightness based on the determined spatial axis and compares them with preset tolerance thresholds, thereby achieving automated and highly efficient quality assessment. The overall system solution effectively solves the problems of contact measurement damage, incomplete three-dimensional data acquisition, and inability to perform 100% online full inspection in the existing technology, and significantly improves the detection efficiency and reliability of IVD sample dispensing syringes.

[0108] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A non-contact method for measuring the concentricity and straightness of an IVD sample dispensing syringe, characterized in that, include: Obtain the IVD sample dispensing syringe to be tested; The IVD sample dispensing syringe to be tested is placed in an air-float support state, and the IVD sample dispensing syringe to be tested is controlled to rotate around the axis at a preset angular velocity. For the IVD sample tube under test, which is in the air-bearing support state and rotates around the axis of the IVD sample tube under test at the preset angular velocity, a low-coherence white light interferometry method is used to simultaneously scan from multiple axial positions and multiple angles around the axis of the IVD sample tube under test to obtain surface contour information covering the entire circumference of the IVD sample tube under test. The surface contour information is converted into three-dimensional spatial data, and a measurement coordinate system is established that is fixed to the IVD sample dispensing syringe under test; The three-dimensional spatial data is processed to identify the geometric features of the IVD sample dispensing syringe under test, and the spatial axis of the IVD sample dispensing syringe under test is determined based on the geometric features. Calculate the concentricity and straightness of the IVD sample dispensing syringe to be tested according to the spatial axis; The concentricity and straightness are compared with the corresponding concentricity tolerance threshold and straightness tolerance threshold, respectively, and the quality of the IVD sample dispensing syringe to be tested is judged according to the comparison results.

2. The non-contact measurement method for the concentricity straightness of the IVD sample dispensing syringe according to claim 1, characterized in that, The process of processing the three-dimensional spatial data, identifying the geometric features of the IVD sample dispensing syringe under test, and determining the spatial axis of the IVD sample dispensing syringe under test based on the geometric features includes: Perform local curvature analysis on the three-dimensional spatial data to identify the curvature variation region along the axial direction on the surface of the IVD sample dispensing syringe under test; The least-squares cylindrical fitting is performed on the sampling points of the inner and outer walls within the curvature variation region to obtain the cylindrical surface fitting residual of the IVD sample dispensing syringe under test. Based on the axial distribution of the fitting residuals of the cylindrical surface, the cross sections where the residuals are greater than the residual threshold are marked as local geometric anomaly regions; The IVD sample dispensing syringe to be tested is divided into multiple sub-regions along the axial direction, and the residual of the sampling point in each sub-region does not exceed the residual threshold. A weighted least squares cylindrical fitting is performed on the sampling points within each sub-region, with the weights being the local signal-to-noise ratio of the corresponding sampling point, to obtain the local axis of the sub-region; The spatial axis of the IVD sample dispensing syringe is obtained by weighting the local axes of each sub-region according to the local signal-to-noise ratio.

3. The non-contact measurement method for the concentricity straightness of the IVD sample dispensing syringe according to claim 2, characterized in that, The step of obtaining the spatial axis of the IVD sample dispensing syringe by weighting the local axes of each sub-region according to the local signal-to-noise ratio includes: For the connection region between two adjacent local axes, the rate of curvature change and tangent direction are calculated to obtain the transition type of the connection region. The transition type includes unidirectional transition, angled transition, and misaligned transition. Select the corresponding spline smoothing function according to the transition type; Calculate the distance deviation, angle deviation, and curvature deviation of the two adjacent local axes at the connection point; A sequence of transition points is generated in the connection region according to the selected spline smoothing function, and the spatial position of each transition point in the sequence of transition points is adjusted to minimize the weighted sum of the distance deviation, the angle deviation, and the curvature deviation. The adjusted transition point sequence is connected to the unadjusted local axis segment to obtain the spatial axis of the IVD sample dispensing syringe to be tested.

4. The non-contact measurement method for the concentricity straightness of the IVD sample dispensing syringe according to claim 1, characterized in that, After processing the three-dimensional spatial data, identifying the geometric features of the IVD sample dispensing syringe to be tested, and determining the spatial axis of the IVD sample dispensing syringe to be tested based on the geometric features, the method further includes: According to the spatial axis, measurement points whose distance deviation from the spatial axis exceeds a first preset threshold are marked as first-type abnormal points; Measurement points whose distance deviation from the spatial axis does not exceed the second preset threshold and are not marked as the first type of abnormal point are marked as valid measurement points, wherein the second preset threshold is less than the first preset threshold, and the second preset threshold is a threshold that points that contribute to the final axis calculation must satisfy; The first type of outlier points are removed from the three-dimensional spatial data, and the spatial axis is recalculated based on the remaining valid measurement points to obtain the updated spatial axis. The low-coherence white light interferometry method is used to perform a second round of scanning on the IVD sample needle under test. The scanning resolution and scanning field of view are adjusted according to the updated spatial axis to obtain the second round of surface contour information. The first round of surface contour information and the second round of surface contour information are fused according to the coordinate registration result to obtain the fused surface contour information; The three-dimensional spatial data corresponding to the fused surface contour information is used as the data basis for the final calculation of the concentricity and the straightness.

5. The non-contact measurement method for the concentricity straightness of the IVD sample dispensing syringe according to claim 1, characterized in that, The step of comparing the concentricity and straightness with the corresponding concentricity tolerance threshold and straightness tolerance threshold, respectively, and judging the quality of the IVD sample dispensing syringe to be tested based on the comparison results includes: The spatial axis is divided into regions to identify characteristic areas on the IVD sample dispensing syringe where the material response characteristics differ from the substrate or where the surface is covered with a functional coating; Obtain the material properties or coating optical parameters of the feature region; According to the material property parameters or the coating optical parameters, a local reference axis definition rule and a local tolerance threshold are set for the feature region. The local tolerance threshold is different from the default tolerance threshold used in the region outside the feature region. Calculate the local concentricity and local straightness of the feature region according to the local reference axis definition rules; The measurement results of the feature region are judged using the local tolerance threshold, and the measurement results of the region outside the feature region are judged using the default tolerance threshold. By integrating the quality assessment results of the characteristic region with those of the region outside the characteristic region, the overall quality assessment of the IVD sample dispensing syringe to be tested is obtained.

6. The non-contact measurement method for the concentricity straightness of the IVD sample dispensing syringe according to claim 5, characterized in that, The process of dividing the spatial axis into regions and identifying characteristic regions on the IVD sample dispensing syringe where the material response characteristics differ from the substrate or where the surface is covered with a functional coating includes: A non-contact spectral imaging method was used to acquire surface spectral response data at different wavelengths along the axial direction of the IVD sample dispensing needle under test. Based on the axial distribution of the surface spectral response data, identify differences in material response or coating optical response; By combining the local curvature distribution and geometric feature changes of the IVD sample dispensing syringe under test, the starting and ending positions of the material response difference or surface functional coating area are determined; The feature region is divided according to the starting position and the ending position.

7. The non-contact measurement method for the concentricity straightness of the IVD sample dispensing syringe according to claim 6, characterized in that, The method employs non-contact spectral imaging to acquire surface spectral response data at different wavelengths along the axial direction of the IVD sample dispensing needle under test, including: Based on the surface reflection and light transmission characteristics of the IVD sample dispensing syringe to be tested, select the wavelength range and light source intensity; When the reflectivity of the IVD sample syringe surface under test is higher than the reflectivity threshold, a high-angle incident and low-angle received optical path configuration is adopted, and polarized light technology is combined to obtain the diffuse reflectance spectrum signal of the IVD sample syringe surface under test. When the surface of the IVD sample syringe under test is transparent, multiple wavelengths with different penetration depths are selected for scanning, and the focusing depth and detector gain are adjusted at each wavelength to obtain spectral information of the IVD sample syringe at different depth levels. The spectral signal at each wavelength is sampled multiple times and the average value is taken to obtain the denoised spectral data; The light source intensity and detector response are calibrated before each scan to obtain the calibrated spectral data.

8. The non-contact measurement method for the concentricity straightness of the IVD sample dispensing syringe according to claim 1, characterized in that, The method employs low-coherence white light interferometry to simultaneously scan from multiple axial positions and multiple angles around the axis of the IVD sample syringe under test, acquiring surface contour information covering the entire circumference of the IVD sample syringe under test, including: At multiple axial positions of the IVD sample dispensing needle under test, multiple sets of interference probes distributed around the axis of the IVD sample dispensing needle under test synchronously acquire interference signals from multiple angles surrounding the axis of the IVD sample dispensing needle under test, wherein the multiple sets include at least three sets. The complete surface profile of the IVD sample dispensing syringe under test is reconstructed based on the interference signals at each of the stated axial positions and angles.

9. The non-contact measurement method for the concentricity straightness of the IVD sample dispensing syringe according to claim 1, characterized in that, The step of comparing the concentricity and straightness with the corresponding concentricity tolerance threshold and straightness tolerance threshold, respectively, and judging the quality of the IVD sample dispensing syringe to be tested based on the comparison results includes: The sampling accuracy evaluation value of the IVD sample dispensing syringe to be tested is calculated by weighting the concentricity and straightness according to the preset weights. The quality grade of the IVD sample dispensing syringe is determined by matching the sample dispensing accuracy assessment value with the grade threshold range. The quality grade includes qualified, critical, and unqualified. Output the classification result corresponding to the quality level.

10. A non-contact measurement system for the concentricity straightness of an IVD sample dispensing syringe, characterized in that, include: The rotating support module is used to acquire the IVD sample dispensing needle to be tested, place the IVD sample dispensing needle to be tested in an air-float support state, and control the IVD sample dispensing needle to be tested to rotate around the axis at a preset angular velocity. The optical scanning module is used to scan the IVD sample tube under test, which is in the air-supported state and rotating around the axis of the IVD sample tube under test at the preset angular velocity, simultaneously from multiple axial positions and multiple angles around the axis of the IVD sample tube under test in a low-coherence white light interferometry method, to obtain surface contour information covering the entire circumference of the IVD sample tube under test. The data processing module is used to receive the surface contour information, convert the surface contour information into three-dimensional spatial data, establish a measurement coordinate system fixed to the IVD sample dispensing needle under test, process the three-dimensional spatial data to identify the geometric features of the IVD sample dispensing needle under test, and determine the spatial axis of the IVD sample dispensing needle under test according to the geometric features. The calculation and judgment module is used to calculate the concentricity and straightness of the IVD sample dispensing syringe to be tested according to the spatial axis, compare the concentricity and straightness with the corresponding concentricity tolerance threshold and straightness tolerance threshold respectively, and judge the quality of the IVD sample dispensing syringe to be tested according to the comparison results.

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