Method, system and readable storage medium thereof for detecting high-speed scanning error of digital pathology scanner displacement stage

Abstract

The application discloses a system and method for detecting displacement table high-speed scanning error of a digital pathology scanner, and belongs to the technical field of digital pathology scanning. The application aims to solve the problem that the existing grating ruler detection scheme cannot perceive the Z-direction dynamic drift generated by the displacement table during high-speed movement, resulting in blurred scanning images. The method collects the static height data of the reflection unit of the displacement table through a non-contact distance measuring sensor, generates a standard fitting surface as a reference, then controls the displacement table to perform high-speed simulation scanning, and synchronously collects dynamic height data, calculates the difference between the dynamic data and the static reference at the same position, and realizes accurate quantification of the Z-direction error of high-speed scanning. The application can truly reflect the dynamic performance of the displacement table, and provides reliable data support for equipment research and development, debugging and maintenance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of digital pathological section scanning and precision measurement, and particularly relates to a method and system for detecting high-speed scanning errors of a displacement table of a digital pathological scanner and a readable storage medium thereof. BACKGROUND

[0002] With the rapid development of digital pathological diagnosis technology, high-throughput pathological section scanners have put forward very high requirements on scanning efficiency. The current mainstream equipment usually requires the scanning speed of the displacement table in the horizontal direction to reach 50 mm / s or higher, so as to complete the whole section scanning in a short time. In order to obtain high-resolution images, the digital pathological scanner usually adopts a high-magnification microscope objective, and the depth of field thereof is usually very small.

[0003] In the existing technical solution, in order to ensure clear imaging, a grating ruler is usually used as a core feedback element to realize sub-micron precision positioning. This traditional detection method is to measure and control the motor displacement of the microscope objective height by the grating ruler, and to convert the mechanical position into a digital signal for feedback control.

[0004] However, the existing technology has significant limitations: the grating ruler can only monitor the vertical movement of the objective lens or the Z-axis motor, but cannot perceive the situation generated by the displacement table itself during high-speed horizontal movement. During high-speed scanning, the displacement table often generates actual Z-axis direction drift (jumping) due to external vibration, structural resonance, loose fixing parts, excessive torque, or uneven guide rails, etc. This leads to a hidden fault phenomenon: the error value fed back by the grating ruler is very small (displayed within the allowable range), but the system has actually exceeded the depth of field range of the objective lens, ultimately resulting in poor clarity and poor quality of the pathological images obtained by scanning. At present, there is a lack of an effective method that can quantitatively measure and guide the optimization of such high-speed dynamic Z-direction errors. SUMMARY

[0005] The embodiments of the present application provide a method and system for detecting high-speed scanning errors of a displacement table of a digital pathological scanner and a readable storage medium thereof, which can solve the problems that the existing technology can only feedback the vertical displacement of the objective lens driving end through the grating ruler, and cannot detect the actual Z-direction dynamic drift generated by the displacement table during high-speed horizontal scanning due to vibration or deformation, resulting in that the system feedback data meets the standard but the actual imaging is blurred.

[0006] The core technology of the present application is mainly to construct a detection system containing a laser sensor and a reflection unit, and to accurately calculate and quantify the Z-direction dynamic error of the displacement table during high-speed scanning by comparing the static sampling height data (establishing a standard fitting surface) and the dynamic sampling height data of the displacement table under the same preset path.

[0007] In a first aspect, the present application provides a method for detecting high-speed scanning error of a displacement table of a digital pathology scanner, the digital pathology scanner comprising a displacement table, a reflection unit arranged on the displacement table, and a non-contact distance sensor located above the reflection unit;

[0008] The method comprises the following steps:

[0009] The displacement table is controlled to move according to a preset path, and the non-contact distance sensor is controlled to collect static height data of the reflection unit at a plurality of preset sampling points;

[0010] According to the static height data of the plurality of preset sampling points, a standard fitting surface is generated, the standard fitting surface representing the spatial geometric shape of the reflection unit in a static state;

[0011] The displacement table is controlled to move through the plurality of preset sampling points at a preset scanning speed, and the non-contact distance sensor is controlled to collect dynamic height data of the reflection unit at each sampling point;

[0012] The difference between the static height data and the dynamic height data corresponding to the same sampling point is calculated to obtain Z-direction error data of the displacement table in the high-speed scanning process.

[0013] Further, the step of controlling the displacement table to move through the plurality of preset sampling points at a preset scanning speed specifically comprises:

[0014] The three-dimensional coordinate data of the standard fitting surface is inputted into a control system as a motion instruction;

[0015] The displacement table is driven to move at high speed in the horizontal direction, and the Z-axis height is adjusted according to the motion instruction to simulate the focusing motion track in the actual pathological section scanning.

[0016] Further, in the process of collecting the dynamic height data, a position triggering mode is adopted to realize data synchronization;

[0017] When the position signal fed back by the encoder of the displacement table matches the coordinate value of the preset sampling point, a pulse signal is directly outputted by hardware or the non-contact distance sensor is triggered for collection by software interruption.

[0018] Further, before collecting the static height data, a pre-checking step is further included:

[0019] The displacement table is controlled to move a preset distance in the horizontal direction, and the non-contact distance sensor is used to detect the height variation range;

[0020] If the height variation range exceeds a preset levelness threshold, it is determined that the inclination of the displacement table is too large, and the displacement table needs to be leveled.

[0021] Further, after calculating the difference between the static height data and the dynamic height data corresponding to the same sampling point, an error evaluation step is further included:

[0022] For the Z-direction error data of all sampling points, the maximum error value and the minimum error value are selected to be subtracted to obtain an error range value.

[0023] It is determined whether the error range value is less than a preset qualified threshold value; if greater than the qualified threshold value, it is determined that the displacement table high-speed scanning error is not up to standard.

[0024] Further, the preset path is an S-shaped path, and the preset sampling points are uniformly distributed in a matrix form in the detection area of the reflection unit.

[0025] Further, the reflection unit is an optical flat crystal or a standard glass slide with a flat surface.

[0026] In a second aspect, the present application provides a device for detecting high-speed scanning error of a displacement table of a digital pathology scanner, comprising:

[0027] The displacement table is used to carry the reflection unit and can perform high-speed scanning movement in the horizontal direction and height adjustment in the Z-direction.

[0028] The non-contact distance measuring sensor is independently arranged from the displacement table and located within the working distance range above the reflection unit, and is used to collect height data of the reflection unit.

[0029] The control and calculation unit is in communication connection with the displacement table and the non-contact distance measuring sensor.

[0030] The control and calculation unit is configured to perform the method steps as described above.

[0031] Further, a gantry base is further included, and the non-contact distance measuring sensor is mounted on the gantry base through a fixing member to isolate the vibration generated by the movement of the displacement table; the non-contact distance measuring sensor is a laser displacement sensor.

[0032] In a third aspect, the present application provides a computer readable storage medium having a computer program stored thereon, and the computer program is executed by a processor to implement the method as described above.

[0033] The main contributions and innovations of the present application are as follows:

[0034] 1. Realize real quantification of high-speed dynamic error: solve the "blind area" of the traditional grating ruler detection scheme, and can accurately measure the actual Z-direction offset generated by the displacement table during high-speed movement (such as above 50mm / s), and ensure that the measurement result truly reflects the risk of defocus during scanning.

[0035] 2. Establish scientific error evaluation standard: the application proposes an error evaluation system based on "static fitting surface" as the benchmark, especially by calculating the difference range (the difference between the maximum value and the minimum value) of dynamic and static data, to ensure that each spliced small image obtained by scanning is strictly within the objective lens depth of field range, thereby ensuring the overall imaging quality.

[0036] 3. Effective guidance for research and development and maintenance optimization: through specific error data analysis, the method can help researchers accurately locate the error source (such as displacement table tilt, resonance at a specific speed, PID parameter setting or insufficient rigidity of hardware structure), so as to implement targeted optimization measures (such as avoiding resonance speed, adjusting levelness, optimizing PID parameters, etc.), significantly reducing the research and development cost of new structure displacement table and improving the equipment maintenance efficiency.

[0037] The details of one or more embodiments of the application are presented in the following drawings and description, so that other features, objects and advantages of the application are more apparent. BRIEF DESCRIPTION OF DRAWINGS

[0038] The drawings described herein are intended to provide further understanding of the application, and form a part of the application. The illustrative embodiments of the application and their description serve to explain the application without forming an improper limitation of the application. In the drawings:

[0039] Figure 1 It is a system architecture diagram for detecting high-speed scanning error of displacement table of digital pathology scanner according to an embodiment of the application;

[0040] Figure 2 It is a sampling point distribution and displacement table scanning path schematic diagram in the detection process according to an embodiment of the application;

[0041] Figure 3 It is a standard fitting surface schematic diagram generated by collected static height data according to an embodiment of the application;

[0042] Figure 4 It is a principle schematic diagram of Z-direction error caused by displacement table tilt according to an embodiment of the application;

[0043] Figure 5 It is a dynamic height data and standard fitting surface visualization diagram when the displacement table is tilted by 50um according to an embodiment of the application;

[0044] Figure 6 It is a dynamic data and static data error curve diagram when the displacement table is tilted by 50um according to an embodiment of the application;

[0045] Figure 7 It is a dynamic height data and standard fitting surface visualization diagram when the displacement table is tilted by 10um according to an embodiment of the application;

[0046] Figure 8 is a dynamic data and static data error curve diagram when the displacement table is tilted 10 um according to an embodiment of the present application;

[0047] Figure 9 is a scanning imaging effect comparison diagram when the displacement table is tilted 50 um (left) and 10 um (right) according to an embodiment of the present application;

[0048] Figure 10 is a scanning imaging effect comparison diagram when the scanning speed is 40 mm / s (left) and 70 mm / s (right) according to an embodiment of the present application;

[0049] Figure 11 is a dynamic height data point and standard fitting surface visualization diagram before optimization according to an embodiment of the present application;

[0050] Figure 12 is a dynamic height data point and standard fitting surface visualization diagram after adjusting the software PID parameters according to an embodiment of the present application;

[0051] Figure 13 is a dynamic data and static data error curve diagram after adjusting the software PID parameters according to an embodiment of the present application;

[0052] Figure 14 is a dynamic height data point and standard fitting surface visualization diagram after optimizing the hardware structure according to an embodiment of the present application;

[0053] Figure 15 is a dynamic data and static data error curve diagram after optimizing the hardware structure according to an embodiment of the present application;

[0054] Figure 16 is a scanning imaging effect comparison diagram after adjusting the software parameters (left) and optimizing the hardware structure (right) according to an embodiment of the present application. DETAILED DESCRIPTION

[0055] The exemplary embodiments will be described in detail herein with reference to the attached drawings. The description of the exemplary embodiments is intended to apply to all alternative embodiments, as would be understood by one skilled in the art. Overly detailed description of the system and method according to the exemplary embodiments, however, would obscure the application in some instances. Therefore, some of the exemplary embodiments will be described herein with reference to the attached drawings.

[0056] It should be noted that the steps of the corresponding method are not necessarily performed in the order shown and described in the present specification in other embodiments. In some other embodiments, the steps included in the method thereof can be more or less than described in the present specification. In addition, a single step described in the present specification can be divided into multiple steps for description in other embodiments; and multiple steps described in the present specification can also be combined into a single step for description in other embodiments.

[0057] Embodiment I: Hardware architecture of the detection system

[0058] As shown in the figure, the present embodiment provides a system for detecting high-speed scanning error of a digital pathology scanner displacement stage. The system mainly comprises a computer, a driving unit, a displacement stage control unit (control unit 1), a sensor control unit (control unit 2), a scanner displacement stage, a non-contact distance measuring sensor, and a reflection unit. Figure 1 Specifically, the scanner displacement stage is used to place a slide, and in the detection mode, the bearing area thereof is placed with the reflection unit. In the present embodiment, the reflection unit is preferably an optical flat or a standard slide with a flat surface, which is used to reflect the probe light from the distance measuring sensor.

[0059] The non-contact distance measuring sensor (preferably LK-G5000 laser sensor of Keyence in the present embodiment) is placed within the effective working distance range above the reflection unit. In order to ensure the accuracy of the measurement and exclude the interference of the vibration of the displacement stage itself, the laser sensor is fixed by a fixing member (such as a gantry base extension, conventional technical means, which will not be described here) and separated from the base of the displacement stage, so as to realize independent measurement of the Z direction deviation in the high-speed motion of the displacement stage.

[0060] The driving unit is used to control the displacement stage to move horizontally in X / Y axis and control the piezoelectric ceramic motor to adjust the Z axis height of the microscope objective lens. The computer is in communication connection with the control unit 1 and the control unit 2 respectively. Among them, the control unit 1 is used to control the displacement stage to run according to the preset path and point position; and the control unit 2 is used to control the data acquisition of the laser sensor.

[0061] In order to realize accurate acquisition under high-speed motion, the present system adopts a position trigger synchronization mechanism. Specifically, when the real-time position count of the displacement stage encoder feedback matches the preset sampling point coordinate value, the hardware directly outputs TTL pulse to trigger the laser sensor with a delay as low as microseconds by using the position comparison trigger function of the motion control card; or the encoder position is read in real time by the controller, and the sampling is triggered by software interruption.

[0062] Embodiment II: General process of error detection method

[0063] As shown in the figure, the present embodiment provides a system for detecting high-speed scanning error of a digital pathology scanner displacement stage. The system mainly comprises a computer, a driving unit, a displacement stage control unit (control unit 1), a sensor control unit (control unit 2), a scanner displacement stage, a non-contact distance measuring sensor, and a reflection unit.

[0064] Figure 2 ​As shown, the embodiment provides a method for detecting displacement table high-speed scanning error by using the above system, and the specific steps are as follows:

[0065] 1. System preheating and initialization: turn on the laser sensor for preheating to eliminate the interference of temperature drift on the test accuracy. Preferably, continuously stand for a certain time (such as 1 hour) to ensure that the sensor value fluctuation is within the allowable error (such as 100nm-200nm).

[0066] 2. Displacement table levelness pre-check: control the displacement table to move along the X / Y direction by a preset distance (20cm in the embodiment), and use the laser sensor to detect the height change range. If the height change exceeds the preset threshold (preferably 15um in the embodiment), it indicates that the inclination of the displacement table is too large, which will amplify the projection of the horizontal motion error on the Z axis, and the displacement table supporting leg needs to be adjusted until the levelness meets the standard.

[0067] 3. Static data acquisition: the computer drives the displacement table to move according to the preset scanning path (such as S-shaped path, as shown in Figure 2 The displacement table stops at each preset sampling point (for example, 100 points distributed in a 10x10 matrix), at which time the laser sensor collects static height data and returns them to the computer.

[0068] 4. Generating a standard fitting surface: the computer generates a standard fitting surface (such as Figure 3 as shown) according to a series of static height data points collected in step 3 by a fitting algorithm (existing technology, such as Least Squares Method, Polynomial Surface Fitting, RANSAC algorithm (Random Sample Consensus algorithm), etc., which is not the technical feature to be protected by the present application, so it will not be described again). Since the reflection unit is an optical flat crystal, the fitting surface usually presents an inclined plane. The surface represents the geometric shape of the displacement table in the ideal static state, and each coordinate point (x, y, z) on the surface is the motion instruction reference in the subsequent dynamic scanning.

[0069] 5. Dynamic data acquisition: according to the Z value instruction of the standard fitting surface, control the piezoelectric ceramic of the displacement table carrying the microscope objective to perform focusing action, and control the displacement table to continuously pass through the above sampling points (without stopping) at a preset high-speed scanning speed (such as 50mm / s). In this process, the laser sensor collects dynamic height data of the reflection unit at each sampling point in real time through the above position trigger signal.

[0070] 6. Error calculation and evaluation: the computer calculates the difference between the static height data and the dynamic height data corresponding to each sampling point. The "error range" is used as an evaluation index, that is, the difference between the maximum and minimum values of all sampling point error data. If the range is less than the pre-set qualified threshold (1 um in this embodiment, to ensure that it is within the depth of field range), it is determined to be qualified; otherwise, optimization is required.

[0071] Example Three: Influence of displacement table inclination on error and optimization

[0072] This example shows that excessive inclination of the displacement table causes errors. As shown in Figure 4 , the laser sensor position is unchanged, and the inclined reflection unit plane moves from left to right in the Figure 4 direction. The positions from left to right are the displacement table to point set by position command and the slightly misaligned position caused by horizontal error during actual movement, respectively. It can be seen that the greater the slope, the greater the error of the horizontal slight misalignment in the z direction, thereby causing the actual sample height to deviate from the depth of field range when the microscopic objective lens reaches the set height position according to the original command during high-speed movement.

[0073] This example demonstrates the importance of displacement table level adjustment through a comparative experiment.

[0074] In Experiment One, the displacement table has a large inclination, and the detected height change is about 50 um when moving 20 mm in the horizontal direction. According to the steps in Example Two, dynamic collection is performed at a speed of 50 mm / s. As shown in Figure 5 and Figure 6 , most of the dynamic sampling points do not fall on the standard fitting surface, and the difference between the maximum and minimum values of the calculated error is as high as 1.401 um, exceeding the qualified standard of 1 um, indicating that out-of-focus blur will occur during imaging.

[0075] In Experiment Two, the adjustable support feet of the scanner displacement table are adjusted so that the height change is less than 10 um when moving 20 mm in the horizontal direction. Repeat the above collection steps, and the results are shown in Figure 7 and Figure 8 , most of the dynamic sampling points fall on the standard fitting surface, and the error range calculated is only 0.256 um, which is much smaller than the standard of 1 um.

[0076] Figure 9 The scanning images of the same field of view of pathological sections in the above two states are shown, and it can be seen that the image clarity after leveling optimization (right image) is significantly better than that before optimization (left image). This verifies the effectiveness of the detection method in guiding the assembly and debugging of the displacement table hardware.

[0077] Example Four: Selection of scanning speed and resonance avoidance

[0078] This embodiment uses the method of the application to analyze the relationship between scanning speed and Z-direction error to determine the optimal scanning speed.

[0079] On the same adjusted displacement table, the scanning speeds of 30 mm / s, 40 mm / s, 50 mm / s, 60 mm / s, 70 mm / s, and 80 mm / s were set respectively, and the detection was performed according to the steps of Example Two. The detection results are as follows:

[0080] When the scanning speed was 30 mm / s, the maximum error range was 0.301 um;

[0081] When the scanning speed was 40 mm / s, the maximum error range abnormally increased to 4.06 um, indicating that the displacement table structure produced resonance at this speed;

[0082] When the scanning speed was 50 mm / s, the maximum error range was 0.357 um;

[0083] When the scanning speed was 60 mm / s, the maximum error range was 0.485 um;

[0084] When the scanning speed was 70 mm / s, the maximum error range was 0.727 um, still less than the threshold value of 1 um;

[0085] When the scanning speed was 80 mm / s, the maximum error range reached 1.085 um, exceeding the threshold value.

[0086] Experiments show that high-speed motion amplifies the geometric error and dynamic force of the displacement table, and there is a resonance interval. Through the detection method, the designer can avoid the resonance speed of 40 mm / s, and ultimately select 70 mm / s as the optimal scanning speed considering efficiency and quality. Figure 10 The comparison chart as shown in Figure 10 also confirms that the imaging quality at the speed of 70 mm / s (the right graph of Figure 10 ) is significantly better than that at the resonance speed of 40 mm / s (the left graph of ).

[0087] Example Five: Comprehensive optimization of PID parameters and structural rigidity

[0088] This embodiment shows the optimization process when the error is found to be regularly distributed (such as line-by-line deviation).

[0089] In the initial test, the dynamic data points presented a regularity of being located above / below the standard fitting surface line-by-line (such as the lower graph of Figure 11 ), and the error was large. The analysis reason may involve the straightness of the guide rail, the amplification of Abbe error caused by pitch / yaw angle during acceleration / deceleration, or improper PID parameter setting.

[0090] First, software optimization was performed: adjusting acceleration (reduced to 1 / 2 of the original value) and start-stop speed (increased to 2 times the original value), and tuning the PID parameters. After several debugging, the P value was set to 300, the I value was set to 25, and the D value was set to 600 (as shown in Table 1). The results after optimization are shown in the lower graph of Figure 12 It can be seen that the results of the lower graph (after parameter adjustment) of Figure 12 are better than the upper graph (before parameter adjustment) of Figure 12 , but still have many points that do not fall on the standard fitting surface) and Figure 13 , the maximum error is 1.88 um, although the waveform has improved, but still not up to standard.

[0091] Table 1

[0092]

[0093] Subsequently, hardware optimization was performed: for the problem of structural elastic deformation, a material with stronger rigidity was replaced as the cantilever of the displacement stage, and the length of the cantilever was shortened by 2 cm, and the object table piece clamp was also reinforced. Again, the test was performed, and the results are shown in Figure 14 and Figure 15 , the maximum error difference is reduced to 0.786 um, meeting the standard of less than 1 um. Figure 16 The image comparison of again verifies the effectiveness of the optimization process, and it can be seen that the right graph is significantly clearer than the left graph.

[0094] In summary, the system and method provided by the present application not only can quantitatively detect the real Z-direction error of the displacement stage under high-speed scanning, but also can provide clear guidance for software and hardware optimization through error data characteristics (such as numerical value, distribution law), thereby solving the blind area problem of the traditional grating ruler detection scheme.

[0095] Those skilled in the art should understand that the technical features of the above embodiments can be combined in any way, and in order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0096] The above embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the present application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method for detecting high-speed scanning errors of a digital pathology scanner's stage, characterized in that, The digital pathology scanner comprises a displacement stage, a reflection unit arranged on the displacement stage, and a non-contact distance measuring sensor located above the reflection unit; The method comprises the following steps: controlling the displacement stage to move according to a preset path, and causing the non-contact distance measuring sensor to collect static height data of the reflection unit at a plurality of preset sampling points; generating a standard fitting surface according to the static height data of the plurality of preset sampling points, the standard fitting surface representing the spatial geometric shape of the reflection unit in a static state; controlling the displacement stage to move through the plurality of preset sampling points at a preset scanning speed, while controlling the non-contact distance measuring sensor to collect dynamic height data of the reflection unit at each sampling point; calculating the difference between the static height data and the dynamic height data corresponding to the same sampling point to obtain Z-direction error data of the displacement stage in the high-speed scanning process.

2. The method of claim 1, wherein, The step of controlling the displacement stage to move through the plurality of preset sampling points at a preset scanning speed specifically comprises: inputting the three-dimensional coordinate data of the standard fitting surface as a motion instruction into a control system; driving the displacement stage to move at high speed in the horizontal direction, and adjusting the Z-axis height according to the motion instruction to simulate the focusing motion track in the actual pathological section scanning.

3. The method of claim 1, wherein, In the process of collecting the dynamic height data, a position triggering mode is adopted to realize data synchronization; When the position signal fed back by the encoder of the displacement stage matches the coordinate value of the preset sampling point, a pulse signal is directly output by hardware or the non-contact distance measuring sensor is triggered for collection through software interruption.

4. The method of claim 1, wherein, Before collecting the static height data, a pre-checking step is further included: controlling the displacement stage to move a preset distance in the horizontal direction, and detecting the height variation range by using the non-contact distance measuring sensor; if the height variation range exceeds a preset levelness threshold, it is determined that the inclination of the displacement stage is too large, and the displacement stage needs to be leveled.

5. The method of claim 1, wherein, After calculating the difference between the static height data and the dynamic height data corresponding to the same sampling point, an error evaluation step is further included: for the Z-direction error data of all sampling points, the maximum error value and the minimum error value are subtracted to obtain an error range value; determining whether the error range value is less than a preset qualified threshold; if greater than the qualified threshold, it is determined that the high-speed scanning error of the displacement stage is unqualified.

6. The method of claim 5, wherein, The preset path is an S-shaped path, and the preset sampling points are uniformly distributed in a matrix form in the detection area of the reflection unit.

7. The method of any one of claims 1 to 6, wherein, The reflection unit is an optical flat crystal or a standard glass slide with a flat surface.

8. A system for detecting high speed scanning errors of a digital pathology scanner displacement stage, the system comprising: It comprises: a displacement stage for carrying a reflection unit and capable of high-speed scanning motion in the horizontal direction and height adjustment in the Z-direction; a non-contact distance measuring sensor arranged independently of the displacement stage and located within the working distance range above the reflection unit, for collecting height data of the reflection unit; a control and calculation unit in communication connection with the displacement stage and the non-contact distance measuring sensor; the control and calculation unit is configured to perform the method according to any one of claims 1 to 7.

9. The system of claim 8, wherein, Also included is a gantry base, the non-contact distance measuring sensor is mounted on the gantry base through a fixing piece to isolate the vibration generated by the displacement table movement; the non-contact distance measuring sensor is a laser displacement sensor.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program, when executed by a processor, implements the method of any one of claims 1 to 7.

Images