Displacement detection method for anti-dazzling screen of electronic balance based on micro light hole array

Abstract

The invention relates to the technical field of high-end precision metering instruments and precision sensing detection, in particular to an electronic balance anti-dazzling screen displacement detection method based on a micro light hole array. According to the method, continuous sampling is carried out on a moire fringe optical signal, a continuous phase sequence is obtained through phase demodulation and phase unwrapping, and segmentation processing is carried out on the phase sequence according to a moire fringe phase period; in each phase period section, calculating a first derivative and a second derivative of phase propulsion, judging whether the phase change corresponds to the effective translation displacement of the anti-dazzling screen or not based on the conditions of phase propulsion rate stability, curvature characteristics and cross-period continuity, only performing displacement accumulation calculation on the phase propulsion meeting the judgment conditions, and completing mass conversion accordingly; according to the invention, the influence of non-translation factors on displacement calculation can be reduced, and the measurement stability and effective resolution capability of the electronic balance under the conditions of long-term use and small-range weighing can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of high-end precision metrology instruments and precision sensing and detection technology, and more specifically to a method for detecting the displacement of the light shield of an electronic balance based on a micro-transparent aperture array. Background Technology

[0002] Electronic balances often employ a displacement detection method based on a micro-aperture array and a light-shielding plate. This method achieves high-precision measurement of minute displacements through optical means and converts them into mass signals, making it widely used in high-precision weighing applications. Existing high-precision electronic balances typically use an optical displacement detection structure that combines a fixed micro-aperture array with a movable light-shielding plate array. The fixed aperture array is positioned opposite the light source and photodetector, while the light-shielding plate is linked to the weighing sensor or lever mechanism. When mass is applied to the weighing pan, the sensor undergoes a minute deformation, causing the light-shielding plate to displace relative to the fixed aperture array. Due to the slight difference in the periods of the two aperture arrays, their relative displacement forms a periodically changing moiré fringe light intensity signal. The photodetector collects this light signal, and by counting and interpolating the period and subdivisions of the light intensity changes, the displacement of the light-shielding plate is obtained, which is then further converted into the corresponding mass value. This method features high resolution and good repeatability, making it suitable for electronic balances with microgram-level and higher precision.

[0003] However, the displacement detection methods based on moiré fringes of micro-transmitting aperture arrays mentioned above typically assume an ideal one-dimensional translational relationship between the fixed aperture array and the light-shielding aperture array during displacement calculation. This means they are assumed to remain parallel and without relative angular changes during operation. However, in actual electronic balances, the light-shielding plate is usually connected to the load cell or lever mechanism via a flexible structure. Under conditions such as long-term weighing, off-center loading, or small repetitive loading, it inevitably undergoes minute rotation or tilt changes. While these micro-angle changes are difficult to detect directly using conventional assembly accuracy or calibration methods, they alter the local overlap between the aperture arrays, causing non-ideal phase distortion in the resulting moiré fringes within the detection area. Because this distortion has both positional and directional dependence, existing displacement calculation models based on period counting and interpolation struggle to effectively distinguish and correct it. This easily introduces systematic errors in small or commonly used weighing ranges, leading to decreased long-term repeatability or path-dependent deviations in weighing results, thus affecting the actual measurement stability of the electronic balance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention discloses a method for detecting the displacement of an electronic balance shield based on a micro-transparent aperture array. The aim is to achieve spatial consistency of crack geometry through the collaborative constraint of feature gradients, improve the positioning offset caused by feature compression, and reduce the impact of environmental interference on width estimation.

[0005] To achieve the above-mentioned technical effects, the present invention adopts the following technical solution: A method for detecting the displacement of the light-shielding plate of an electronic balance based on a micro-aperture array includes the following steps: Step 1: During the weighing process, continuously collect the moiré fringe light signal formed by the fixed micro-transmitting aperture array and the light-shielding sheet micro-transmitting aperture array, and obtain the corresponding continuous phase signal through orthogonal demodulation. Perform phase expansion on the continuous phase signal to obtain a monotonically changing expanded phase sequence. Step 2: Using the phase period corresponding to the moiré fringes as the segmentation benchmark, divide the unfolded phase sequence into multiple phase period segments, and establish a phase advancement curve in each phase period segment to show the phase change with the sampling sequence. Step 3: Calculate the first and second derivatives of the phase with respect to the sampling sequence for the phase advance curve within each phase period segment to obtain the phase advance rate distribution and the phase advance rate change distribution within that phase period segment; Step 4: When the difference between the maximum and minimum values ​​of the first derivative within the same phase period segment is less than a preset proportional threshold, the mean square value of the second derivative is less than a preset curvature threshold, and the change in the mean value of the first derivative of adjacent phase period segments is less than a preset continuity threshold, the corresponding phase advance is determined to be an effective phase advance. Step 5: Perform phase accumulation calculation only on the phase period segments that are determined to be effective phase advances to obtain the effective displacement of the light-shielding sheet; Step 6: Perform mass conversion based on the effective displacement and output the weighing result of the electronic balance.

[0006] Furthermore, the working process of step 1 includes: The in-phase and quadrature components of the moiré fringe optical signal are simultaneously demodulated to obtain two mutually orthogonal baseband signals. The instantaneous phase value is calculated based on two baseband signals, and the phase change between adjacent sampling points is compared point by point during continuous sampling. When the absolute value of the phase change exceeds the preset phase jump threshold, the phase change direction and the phase change trend of the previous and next sampling points are combined to determine whether the phase change corresponds to a real phase jump. When a true phase transition is determined, the instantaneous phase is compensated and unfolded to form a monotonically changing unfolded phase sequence, thus avoiding pseudo-phase jumps caused by local distortion of moiré fringe intensity or noise disturbance from participating in the phase unfolding process.

[0007] Furthermore, step 2, which involves dividing the unfolded phase sequence based on the phase period corresponding to the moiré fringes, includes: For the expanded phase sequence The calculation is performed by iterating through the samples in the order they were taken, and the phase increment is calculated between adjacent sample points. ,in, Indicates the index of the current sampling point; Within a sliding window containing L consecutive sampling points, the cumulative phase change is calculated for the phase increment. variance of phase increment The formula for calculating the cumulative phase change is: When the cumulative phase change satisfies Less than the preset phase closure tolerance threshold, and the phase increment variance satisfies When the value is less than the preset phase propulsion stability threshold, the corresponding sampling point will be... As the phase period boundary point, the unfolded phase sequence is divided into multiple consecutive phase period segments accordingly.

[0008] Furthermore, the process of constructing the phase advancement curve includes: Indexed by the starting sampling point of the phase period segment Using the sampled points as reference points, the expanded phase values ​​corresponding to each sampling point within the period are normalized to obtain the phase advancement sequence within the period. Based on the phase-propelling sequence, a corresponding continuous phase-propelling model is constructed through least-squares fitting, with the expression: in, This represents the first-order phase advance coefficient within that phase period. This represents the second-order phase propulsion correction coefficient. This represents the phase-driven residual term. Indicates the first Phase progression curves showing how the phase changes with the sampling sequence within a single phase period.

[0009] Furthermore, the working process of step 3 includes: In the Within each phase period segment, the phase advancement curve constructed within that period segment For the calculation object, select a sampling index interval that covers the phase period segment. Within the sampling index interval, the phase advancement curve is segmented using a sliding sampling window of fixed length; Within each sliding sampling window, the phase advancement data within the window is locally and continuously fitted using the polynomial least squares fitting method to obtain the corresponding local phase function. Based on the local phase function, the first-order phase derivative and the second-order phase derivative at the sampling point at the center of the window are calculated respectively. The sliding sampling window is moved point by point along the sampling sequence direction, and the above local fitting and differentiation process is repeated to form a phase advance rate distribution sequence composed of multiple first-order derivative values ​​and a phase advance rate change distribution sequence composed of multiple second-order derivative values ​​within the entire phase period segment. Each derivative value corresponds one-to-one with the position of the corresponding sampling point within the phase period segment.

[0010] Furthermore, the process of forming the phase advance rate distribution sequence and the phase advance rate change distribution sequence within the phase period segment also includes: In the Within each phase period segment, the first-order phase advance rate distribution sequence obtained by the sliding sampling window and the distribution sequence of second-order phase propulsion rate changes A joint continuity constraint is constructed according to the sampling sequence order, so that the derivative distribution satisfies the consistency of displacement evolution within the same phase period segment; The joint continuity constraint condition includes at least the following: the change in the first-order phase advance rate at adjacent sampling points satisfies The second-order phase advance rate change satisfies the sign consistency constraint within the phase period segment. ,in, Indicates the first Sampling points within each phase period segment The first-order phase propulsion rate at that point, This represents the change in the second-order phase propagation rate at the corresponding sampling point. A continuity threshold is set to limit the variation of the phase advance rate between adjacent sampling points; The derivative values ​​that satisfy the above joint continuity constraints are retained in the corresponding phase advance rate distribution sequence and phase advance rate change distribution sequence.

[0011] Furthermore, step 4 also includes performing joint normalization and consistency verification on the multidimensional derivative criterion within the phase period segment, the process of which is as follows: In the Within a phase period segment, based on the first-order phase propulsion rate distribution sequence of that period segment and the distribution sequence of second-order phase propulsion rate changes Calculate the range ratio parameter of the first-order phase propulsion rate respectively. Mean square curvature parameters of the second-order phase propulsion rate change The calculation formulas are as follows: in, Indicates the first The average first-order phase advance rate within each phase period segment. This indicates the number of valid sampling points within the phase period segment; For adjacent phase period segments and Calculation of the mean first-order phase propulsion rate across periods The calculation formula is: When the range ratio parameter Mean square curvature parameter and cross-cycle change When all three types of parameters simultaneously satisfy their respective preset constraints and are constructed based on the effective derivative distribution within the same phase period segment during the calculation process, the phase advance corresponding to that phase period segment is determined to be an effective phase advance; wherein, the preset constraints correspond to the intra-period consistency of the phase advance rate, the overall stability of the phase advance curvature, and the continuous evolution characteristics of the phase advance between adjacent period segments.

[0012] Furthermore, the determination of effective phase advance in step 4 is based on the stable advance interval within the phase period segment, specifically including: In the Within a phase period segment, based on the first-order phase propulsion rate distribution sequence of that period segment The set of sampling points that satisfy the continuity constraint of phase advance rate change is identified according to the sampling sequence, and the part that forms a continuous sampling interval is determined as the stable advance interval within the phase period segment. Within the stable propulsion interval, the maximum, minimum, and mean values ​​of the first-order phase propulsion rate are calculated respectively, and the first-order derivative statistical parameters for judgment are constructed accordingly. At the same time, the mean square value of the corresponding second-order phase propulsion rate change is calculated within the same interval. When the number of sampling points covered by the stable propulsion interval is not less than a preset proportion of the number of effective sampling points in the phase period segment, the derivative statistical parameters obtained in the phase period segment are allowed to be used to determine the effectiveness of phase propulsion; otherwise, the effective phase propulsion determination is not performed for the phase period segment.

[0013] Furthermore, the phase accumulation calculation process includes: For each phase period segment that is determined to be a valid phase advance, the unfolded phase value is extracted only within the stable advance interval corresponding to that phase period segment, and the unfolded phase corresponding to the starting sampling point of that stable advance interval is used as the reference benchmark for phase accumulation within the period. Within the stable propulsion range, the unfolded phase corresponding to the end sampling point is subtracted from the reference reference to obtain the effective phase increment corresponding to the phase period segment; The effective phase increments obtained from multiple effective phase period segments are accumulated in chronological order to form a cumulative phase quantity used to characterize the effective displacement of the light-shielding sheet.

[0014] Furthermore, the working process of step 6 includes: The cumulative phase quantity obtained in step 5 is converted into the corresponding effective displacement quantity, and the displacement mass conversion relationship corresponding to the path is generated based on the effective displacement quantity to perform mass calculation. The displacement mass conversion relationship is established by fitting the effective displacement quantity corresponding to multiple sets of known standard masses during the calibration process of the electronic balance. In the actual weighing process, only the effective displacement amount obtained based on the effective phase advancement accumulation is used in the displacement-mass conversion calculation, thereby outputting a weighing result that corresponds one-to-one with the effective displacement amount.

[0015] Based on the above technical solution, the positive and beneficial effects of the present invention are as follows: 1. This invention performs orthogonal demodulation and phase expansion on the moiré fringe phase signal and constructs a phase advancement curve in units of phase period. It introduces first- and second-order derivative distribution analysis and continuity constraints within the period, and introduces a phase advancement evolution consistency judgment during the period. Only the phase advancement that meets the multidimensional derivative statistical characteristics and stable advancement interval conditions is included in the effective displacement calculation. This systematically excludes abnormal phase changes caused by slight tilting of the light shield, local optical distortion, or transient disturbances during the displacement calculation process, thereby improving the consistency between the displacement detection results and the actual translational displacement.

[0016] 2. This invention models the phase advance within the phase period segment as a continuously differentiable advance curve, and introduces consistency constraints and stable advance interval limitations within the period during the derivative calculation stage. This makes the displacement calculation dependent on the overall evolution characteristics of the phase advance rather than local instantaneous signal changes. Thus, under long-term weighing, repeated loading, and small-range weighing conditions, it effectively reduces the systematic offset caused by noise accumulation or local anomalies, and improves the weighing stability and repeatability consistency of the electronic balance in actual use.

[0017] 3. In the displacement accumulation stage, this invention only performs normalized phase accumulation on the phase period segments that are determined to be effective phase advances. In the mass conversion stage, it clearly establishes and calls the corresponding displacement-mass conversion relationship based on the effective displacement amount, so that the final output weighing result is consistent with the formation path of the effective displacement amount, avoiding the influence of invalid phase advances on the mass conversion. This enhances the interpretability and engineering reliability of the electronic balance weighing results from the method structure. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a schematic diagram of the steps of the present invention; Figure 2 This is a schematic diagram illustrating the working principle of step 2 of the present invention; Figure 3 This is a schematic diagram illustrating the working principle of step 3 of the present invention; Figure 4 This is a schematic diagram illustrating the working principle of step 4 of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0020] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] Unless otherwise defined, all techniques and scientific methods used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The descriptions herein are for the purpose of illustrating particular embodiments only and are not intended to limit the invention. The terms "and / or" as used herein include any and all combinations of one or more of the associated listed items.

[0022] In one possible implementation, the overall structure of the electronic balance still adopts an existing mature solution, including a weighing pan, a force sensing mechanism, a light-shielding plate assembly linked to the force sensing mechanism, and a photoelectric detection assembly. The light-shielding plate is positioned opposite a micro-transparent aperture array plate fixed inside the balance, with a small gap between them along the displacement direction. A stable light source, such as a constant-current driven light-emitting diode, is positioned on the side of the fixed micro-transparent aperture array plate facing away from the light-shielding plate. The light signal passing through the fixed aperture array and the light-shielding plate aperture array is received by at least one set of photodetectors and converted into an electrical signal.

[0023] During the weighing process of an electronic balance, when the object to be measured is placed on the weighing pan, the force sensing mechanism undergoes elastic deformation, causing the light-shielding plate to undergo a slight displacement along a predetermined direction. Because the aperture arrangement period of the light-shielding plate and the fixed micro-transparent aperture array differs slightly, their superposition results in a moiré fringe light signal on the photodetector that varies with the displacement of the light-shielding plate.

[0024] In this embodiment, the analog signal output by the photodetector is first amplified and filtered by an analog front-end, and then sampled by an analog-to-digital converter to form a discrete digital signal. The digital signal is sent to the signal processing module inside the electronic balance. This module can be implemented by a microprocessor, a digital signal processor, or a programmable logic device, and internally executes the displacement detection method of the present invention.

[0025] First, during the weighing process, the signal processing module performs orthogonal demodulation on the continuously acquired moiré fringe optical signals. Specifically, based on a pre-set reference orthogonal signal, the in-phase and quadrature components of the optical signal are extracted to obtain a pair of mutually orthogonal phase basis signals. Subsequently, the corresponding instantaneous phase value is obtained through arctangent operation, and the instantaneous phase value is subjected to phase expansion processing to eliminate phase jumps, resulting in an expanded phase sequence that monotonically varies with the sampling sequence.

[0026] Unlike existing technologies, this embodiment does not directly use the unfolded phase sequence for displacement calculation, but rather uses it as the basis data for subsequent phase evolution analysis. The signal processing module divides the unfolded phase sequence into multiple continuous phase period segments based on the phase period corresponding to the moiré fringes. Each phase period segment corresponds to the displacement process of the light-shielding plate within one aperture array period.

[0027] Within each phase cycle, the signal processing module uses the sampling sequence as the independent variable to establish a phase progression curve showing how the phase changes with the sampling sequence. This phase progression curve reflects the phase evolution of the light-shielding sheet within that cycle, rather than just the phase start and end values.

[0028] Based on this, the signal processing module calculates the first and second derivatives of the phase advance curve with respect to the sampled sequence for each phase period segment. The first derivative characterizes the distribution of the phase advance rate, while the second derivative characterizes the smoothness of the phase advance rate change. Through these derivative calculations, information such as whether the phase advance is uniform and whether there are abrupt changes or bends within that phase period segment can be obtained.

[0029] Furthermore, the signal processing module determines the validity of phase period segments based on the derivative calculation results. Specifically, when the difference between the maximum and minimum values ​​of the first derivative within the same phase period segment is less than a preset proportional threshold, the mean square value of the second derivative is less than a preset curvature threshold, and the change in the mean value of the first derivative between the phase period segment and its adjacent phase period segments is less than a preset continuity threshold, the phase advance within that phase period segment is determined to be a valid phase advance. Phase period segments that do not meet the above conditions are considered to contain non-ideal phase evolution factors and are not included in subsequent displacement calculations.

[0030] In this embodiment, the ratio threshold, curvature threshold, and continuity threshold can be set at the factory according to the range, resolution, and structural characteristics of the electronic balance, or they can be adjusted through the calibration process, but their specific values ​​do not affect the core idea of ​​the present invention.

[0031] After determining the effective phase advance, the signal processing module performs phase accumulation calculations only on the phase period segments determined to have effective phase advance. Specifically, within each effective phase period segment, the signal processing module further defines a stable interval for phase advance, extracts the expanded phase value only within this stable interval, and uses the phase corresponding to the starting point of the stable interval as the phase reference benchmark for that period segment. The effective phase increment corresponding to that period segment is obtained by calculating the difference between the phase at the end of the stable interval and the reference benchmark. Subsequently, the effective phase increments of multiple effective phase period segments are accumulated in chronological order to form a cumulative phase quantity.

[0032] The accumulated phase quantity is then converted into the corresponding effective displacement quantity. It should be noted that this effective displacement quantity is not the theoretical total displacement of the light-shielding plate during the entire weighing process, but rather the displacement quantity contributed only by phase period segments that are determined to have clear physical meaning and stable phase evolution.

[0033] After calculating the effective displacement, the signal processing module performs a mass conversion based on this effective displacement. In this embodiment, during the calibration process, the electronic balance loads multiple sets of known standard masses, records the corresponding effective displacements, and establishes a displacement-mass conversion relationship based solely on the effective displacement. During the actual weighing process, the signal processing module only calls this conversion relationship to convert the effective displacement into the corresponding mass value, which is then output as the final weighing result of the electronic balance.

[0034] To facilitate a deeper understanding of the technology in this invention, a detailed description of the electronic balance light-shielding plate displacement detection method based on a micro-transmittance aperture array disclosed in the embodiments of this application is provided below. Please refer to [link to relevant documentation]. Figure 1 The schematic diagram shown illustrates the steps of the invention, which include: Step 1: During the weighing process, continuously collect the moiré fringe light signal formed by the fixed micro-transmitting aperture array and the light-shielding sheet micro-transmitting aperture array, and obtain the corresponding continuous phase signal through orthogonal demodulation. Perform phase expansion on the continuous phase signal to obtain a monotonically changing expanded phase sequence. In practice, a fixed array of micro-transmitting holes is positioned opposite to an array of micro-transmitting holes in a light-shielding plate that moves with the deformation of the weighing sensor. When the light-shielding plate shifts, the moiré fringes formed by their superposition change in brightness. The transmitted light is converted into an electrical signal by a photodetector, forming a moiré fringe light signal that varies with time.

[0035] In one possible implementation, the photodetector can be a single detector or multiple detectors arranged orthogonally to each other, and its output signal is amplified and filtered analogally before being input to a signal processing unit. The signal processing unit can be a digital signal processor, a microcontroller, or a programmable logic device with digital computing capabilities.

[0036] In the signal processing unit, the moiré fringe optical signal is first synchronously demodulated for both in-phase and quadrature components. Specifically, the signal processing unit generates two mutually orthogonal reference signals corresponding to the fundamental frequency of the moiré fringes. These reference signals are multiplied by the moiré fringe optical signal and then low-pass filtered to obtain two mutually orthogonal baseband signals, denoted as the in-phase component signal and the quadrature component signal, respectively. It should be noted that "in-phase component" and "quadrature component" refer to two baseband signals that are 90 degrees out of phase with the demodulation reference phase. Their purpose is to provide complete phase information for subsequent phase calculations. This concept is different from simple amplitude component separation.

[0037] After acquiring the two baseband signals, the signal processing unit calculates the instantaneous phase value based on the in-phase and quadrature components. As one possible implementation, the instantaneous phase can be calculated using the arctangent function, with the result falling within a predetermined principal value range. During continuous sampling, the signal processing unit compares the instantaneous phase values ​​of adjacent sampling points point by point, calculating the phase change between adjacent sampling points. This phase change reflects the magnitude and direction of the phase change within the current sampling interval.

[0038] When the absolute value of the phase change exceeds a preset phase jump threshold, the signal processing unit does not directly regard the change as a real phase jump. Instead, it further combines the direction of the phase change with the phase change trend of the preceding and following sampling points to make a judgment. That is, the signal processing unit analyzes the phase change of multiple adjacent sampling points before and after the sampling point to determine whether the phase change shows a continuous and consistent trend in time.

[0039] As one possible implementation, when the phase change exceeds the threshold and its direction of change is consistent with the phase change direction of the preceding and following sampling points, and there is no reverse abrupt change in the phase change of the preceding and following sampling points, the signal processing unit determines that the phase change corresponds to a real phase jump; conversely, when the phase change exceeds the threshold but its direction of change is inconsistent with the change trend of adjacent sampling points, or when an isolated abrupt change occurs only at a single sampling point, it is determined to be a pseudo phase jump caused by local distortion of moiré fringe intensity, transient noise disturbance, or non-ideal characteristics of optoelectronic devices.

[0040] It should be noted that "true phase crossing" refers to the situation where the phase continuously advances across the boundary of the principal value interval due to the continuous displacement of the light-shielding plate, while "pseudo-phase jump" refers to the instantaneous phase calculation anomaly caused by non-ideal factors when the actual displacement of the light-shielding plate is continuous. This anomaly does not have stable time evolution characteristics.

[0041] When a true phase crossing is determined, the signal processing unit performs phase compensation expansion on the instantaneous phase. This involves adding or subtracting the corresponding phase period value according to the direction of the phase crossing, based on the original instantaneous phase value, thereby eliminating the main value interval limitation and forming a continuous expanded phase. Through this method, the expanded phase value is updated point-by-point during continuous sampling, ultimately forming an expanded phase sequence that monotonically changes with time.

[0042] When a pseudo-phase transition is identified, the signal processing unit maintains the continuity of the current unfolded phase and does not perform cross-cycle compensation for the instantaneous phase, thereby preventing pseudo-phase transitions from participating in the phase unfolding process.

[0043] Step 2: Using the phase period corresponding to the moiré fringes as the segmentation benchmark, the unfolded phase sequence is divided into multiple phase period segments, and a phase advancement curve is established in each phase period segment to show the phase change with the sampling sequence. This step is not only used to identify the phase period boundary, but also to construct a physically interpretable phase advancement curve within each phase period to support the subsequent determination process based on the consistency of phase advancement.

[0044] For detailed principles, please refer to [link / reference]. Figure 2 In the specific implementation process, the signal processing module processes the expanded phase sequence obtained in step 1. Processing is performed according to the sampling order, where Indicates the index of discrete sampling points. This indicates the total number of sampling points collected during the current weighing process. The unfolded phase sequence is a continuous phase quantity that changes monotonically with time, and its change reflects the continuous displacement of the light-shielding plate during the weighing process.

[0045] First, calculate the phase increment between adjacent sampling points: ,in, Indicates the first The instantaneous change in phase within each sampling period. It should be noted that the "phase increment" is a fundamental statistical quantity describing the continuity of phase advancement time, and its distribution characteristics directly reflect whether the displacement of the light-shielding plate is in a stable advancement state.

[0046] To avoid interference from noise or local optical distortion at a single sampling point in determining the phase period, this embodiment introduces a sliding window of length L. Within this window, the phase increment is accumulated and statistically analyzed. For the current sampling point n, the cumulative phase change is calculated within the sliding window. Here, parameter L represents the number of consecutive sampling points contained in the sliding window; the setting of parameter L is used to limit the minimum expansion scale of a phase period on the time axis. As one possible implementation, L can be set according to the sampling frequency and the typical displacement velocity of the light-shielding plate under normal weighing conditions, so that a complete phase period covers at least multiple sampling points in time, thereby avoiding instantaneous phase changes being misjudged as the completion of the period.

[0047] At the same time, within the same sliding window, the variance of the phase increment is calculated. ,in, This represents the average value of the phase increments within the window.

[0048] The phase increment variance is used to characterize the uniformity of phase advancement within the time window. Its physical meaning is to determine whether the phase advances continuously at a stable rate, rather than being dominated by occasional noise or local interference.

[0049] In this embodiment, when the cumulative phase change satisfies And the phase increment variance satisfies At that time, the corresponding sampling points It is determined to be a phase period boundary point. Among them, Used to define the cumulative phase change and a complete phase period. The allowable deviation range between them These are used to define the stability thresholds for the phase propulsion process. Both constrain the phase period from two different dimensions: "period integrity" and "propulsion consistency." It should be noted that the phase period boundary does not mean that the instantaneous phase value exactly reaches... The definition does not refer to the sampling point, but rather to the position where, during a continuous and stable phase progression over a period of time, the cumulative phase change first completes a full phase cycle. This definition differs from existing period division methods based on single-point thresholds or simple rounding.

[0050] Based on the aforementioned periodic boundary points, the signal processing module divides the unfolded phase sequence into multiple consecutive phase periodic segments.

[0051] After dividing the phase period into segments, a phase progression curve showing the phase change with the sampling sequence is established within each phase period segment. Specifically, for the first... For each phase period segment, select the starting sampling point index of that period segment. Using this as a reference point, the unfolded phase corresponding to each sampling point within the period is normalized to obtain the phase advancement sequence within the period: in, Indicates the first Within each phase period segment, the cumulative advance of the phase relative to the starting position of that period. Through this normalization process, the phase advancement process of different phase period segments is unified under the same reference standard, which facilitates subsequent comparison of the evolution characteristics within each period segment.

[0052] In practice, to characterize the overall evolution trend of phase advancement within the period, rather than simply recording the phase difference between the beginning and end, the signal processing module constructs a continuous phase advancement model based on the phase advancement sequence using the least squares method: in, This represents the first-order phase advance coefficient within the phase period segment, used to characterize the average rate of phase advance. This represents the second-order phase advance coefficient, used to describe the slow acceleration or deceleration trend that may exist during the phase advance process; The phase-propelling residual term reflects the deviation between the actual phase propagation and the model. It should be noted that the phase-propelling model containing first- and second-order terms used in this application is not intended to pursue high-order fitting accuracy, but rather to introduce minimal complexity to characterize the non-ideal characteristics of phase propagation while ensuring model interpretability, thereby providing a clear mathematical foundation for subsequent stability analysis based on first- and second-order derivatives.

[0053] Step 3: Calculate the first and second derivatives of the phase with respect to the sampling sequence for the phase advance curve within each phase period segment to obtain the phase advance rate distribution and the phase advance rate change distribution within that phase period segment. That is, by performing local continuity analysis on the phase advance behavior, the phase advance rate distribution and the phase advance rate change distribution that can truly reflect the displacement evolution characteristics of the light-shielding sheet are extracted, providing a reliable basis for subsequent effective phase advance determination.

[0054] Please see Figure 3 As shown, the specific implementation process is as follows: For the first... For each phase period segment, first select the continuous phase advance curve obtained in step 2 within that phase period segment. As the object of analysis. Among them, For discrete sampling point index, This represents the continuous model value of the phase as it changes with the sampling sequence within this period.

[0055] To avoid uncertainties caused by model extrapolation at the boundary of the periodic segment, this embodiment... Select a sampling index interval covering the phase period segment. ,in, and These represent the starting and ending sampling point indices for the phase period segment, respectively.

[0056] It should be noted that the "phase advance curve" differs from the original unfolded phase sequence. It is a continuous function obtained through fitting, used to describe the overall trend of phase evolution within a period, rather than reflecting a single point measurement value. Therefore, subsequent calculations of the phase advance rate are all based on this continuous curve.

[0057] Within the sampling index interval, this implementation does not use point-by-point differencing to obtain the derivative of the phase advancement curve. Instead, it uses a fixed-length sliding sampling window to segment the phase advancement curve. Let the length of the sliding sampling window be W. Then, at any window position, the sampling index range covered by this window is: in, This indicates the index of the center sampling point of the current sliding window. The purpose of introducing the sliding sampling window is to suppress instantaneous phase jitter caused by photoelectric noise, local distortion of moiré fringes, and uneven light intensity through local data redundancy while maintaining temporal resolution.

[0058] Within each sliding sampling window, this embodiment employs a polynomial least squares fitting method to perform local continuous fitting on the corresponding phase-advancing data within the window. As one possible implementation, the polynomial used is of order two, and its local phase function can be expressed as: in, The coefficients are the polynomial coefficients obtained by fitting within the sliding window. It should be noted that the use of a second-order polynomial in this application is not for pursuing high-order fitting accuracy, but rather based on the engineering fact that the displacement behavior of the light-shielding plate within a single phase period usually exhibits a slow change. By introducing a second-order term, the slight changing trend of the phase advance rate is characterized, while avoiding unnecessary oscillations introduced by higher-order models.

[0059] Based on the aforementioned local phase function, at the sampling point at the center of the sliding window At each point, the first and second derivatives of the phase with respect to the sampled sequence are calculated, and their expressions are as follows: in, Indicates the first Within each phase period segment, at the sampling point Phase advance rate at the location; This represents the change in phase advance rate at the corresponding sampling point, used to characterize the trend of phase advance rate change over time.

[0060] By moving the sliding sampling window point by point along the sampling sequence direction and repeating the above local fitting and differentiation process, a phase advance rate distribution sequence consisting of multiple first-order derivative values ​​can be formed over the entire phase period. and the phase propulsion rate variation distribution sequence composed of multiple second derivative values. Each derivative value corresponds one-to-one with the position of the corresponding sampling point within the phase period segment.

[0061] In the process of forming the above derivative distribution sequence, this embodiment further introduces joint continuity constraints to screen the derivative calculation results, so as to ensure that the retained derivative values ​​can truly reflect the consistency of the displacement evolution of the light-shielding sheet in the phase period segment.

[0062] Specifically, in the Within each phase period segment, the phase advance rate distribution sequence is analyzed according to the sampling sequence order. and phase propulsion rate change distribution sequence Construct joint continuity constraints. As one implementation, these constraints include at least the following two aspects.

[0063] First, the change in the first-order phase advance rate at adjacent sampling points should satisfy: in, This threshold defines the continuity of the phase advance rate variation between adjacent sampling points. It is used to exclude non-physical rate abrupt changes caused by local fitting anomalies or noise amplification.

[0064] Secondly, within the same phase period, the change in the second-order phase propagation rate should satisfy the sign consistency constraint: in, Represents a symbolic function.

[0065] The engineering implications of this sign consistency constraint are that, within a single phase period, the displacement driving state of the light-shielding plate should generally remain consistent, and the trend of its phase advance rate should not frequently reverse between adjacent sampling points. This constraint effectively suppresses the sign reversal of the second derivative caused by local fitting noise.

[0066] The derivative value at a sampling point is retained in the corresponding phase advance rate distribution sequence and phase advance rate change distribution sequence only if the first and second derivative values ​​at a certain sampling point simultaneously satisfy the above joint continuity constraint. Derivative values ​​that do not satisfy the constraint will be marked as invalid points and ignored in subsequent processing.

[0067] It should be noted that the joint continuity constraint described in this application is not a simple smoothing of the phase advance rate, but a structural screening of the derivative results based on the physical consistency of the light-shielding plate displacement. This process provides a high-confidence data basis for subsequent effective phase advance determination.

[0068] Step 4: When the difference between the maximum and minimum values ​​of the first derivative within the same phase period segment is less than a preset proportional threshold, the mean square value of the second derivative is less than a preset curvature threshold, and the average change in the first derivative of adjacent phase period segments is less than a preset continuity threshold, the corresponding phase advance is determined to be an effective phase advance. It should be noted that the "effective phase advance" described in this application is not equivalent to continuous phase changes during phase unfolding, but specifically refers to a phase advance segment that can stably and repeatedly reflect the displacement of the light-shielding sheet in a physically meaningful sense. This determination concept is fundamentally different from the existing technical approach of "phase can be unfolded and thus accumulated."

[0069] In the specific implementation process, for the first Each phase period segment is first determined based on the first-order phase propulsion rate distribution sequence obtained in step 3. and the distribution sequence of second-order phase propulsion rate changes A multidimensional derivative criterion analysis was performed on the phase advancement behavior within the phase period segment.

[0070] in, Indicates the first Within each phase period segment, at the sampling point Phase advance rate at the location; This represents the change in phase advance rate at the corresponding sampling point; the above derivative distributions all satisfy the joint continuity constraint applied in step 3, and therefore can be used as the basic data for stability analysis. For detailed implementation principles, please refer to [link to implementation details]. Figure 4 As shown.

[0071] First, in the Within each phase period segment, the distribution sequence of the first-order phase propulsion rate Calculate its range ratio parameter Its definition is: in, and These represent the maximum and minimum values ​​of the first-order phase advance rate within the phase period segment, respectively. It represents the arithmetic mean of the first-order phase advance rate within the phase period segment.

[0072] The reason for introducing the range ratio parameter instead of directly using variance or standard deviation is that, in the actual operation of an electronic balance, the displacement velocity of the light-shielding plate may vary overall due to different loading conditions, but within a single phase period, its phase advance rate should remain relatively stable. By normalizing the range to the mean, the influence of overall velocity level differences on stability determination can be effectively eliminated.

[0073] Subsequently, within the same phase period, the distribution sequence of the second-order phase propulsion rate variation was analyzed. Calculate the mean square curvature parameter Its definition is: in, This represents the number of effective sampling points for the first and second derivatives participating in the statistics within the phase period. It should be noted that this application uses the mean square value of the second derivative, rather than the mean, as the curvature index based on engineering considerations: during phase advancement, positive and negative curvatures may mathematically cancel each other out, but physically, both positive and negative rate changes imply instability in the displacement advancement process. By squaring, all rate changes can be uniformly mapped to non-negative quantities, thus more realistically reflecting the overall stability of phase advancement.

[0074] After completing the intra-cycle criterion calculation, this embodiment further introduces continuity analysis between adjacent phase period segments. Specifically, for adjacent... The and the first For each phase period segment, calculate the cross-period change in the average first-order phase propulsion rate: in, Indicates the first The average first-order phase advance rate within each phase period segment.

[0075] This cross-period variation is used to characterize the continuous evolution of phase propulsion between adjacent period segments. Its engineering significance lies in the fact that during the weighing process, the displacement driving state of the light-shielding plate usually changes continuously between adjacent Moiré periods, and there should be no abrupt jumps in the propulsion rate.

[0076] In this embodiment, only when the range ratio parameter Mean square curvature parameter and cross-cycle changes Only when each of its corresponding preset constraints is met is the phase period segment considered to exhibit consistent and stable phase advancement behavior both within and during the period. It should be noted that the preset constraints are not fixed values ​​and can be configured based on factors such as the balance model, optical structure dimensions, and sampling frequency. As one possible implementation, these thresholds can be determined during the factory calibration phase using statistical characteristics under no-load and standard load conditions.

[0077] Based on the above-mentioned basic determination, this embodiment further limits the determination of effective phase advance to be completed based on the stable advance interval within the phase period segment, so as to avoid local anomalies within the period segment having a disproportionate impact on the overall determination result.

[0078] Specifically, in the Within each phase period segment, based on the first-order phase propulsion rate distribution sequence The set of sampling points that satisfy the continuity constraint of phase advance rate change in step 3 is identified according to the sampling sequence. The set of sampling points continuously distributed in the sampling sequence is identified as candidate advance intervals. Among these candidate advance intervals, the interval with the longest continuous sampling interval is further selected as the stable advance interval within that phase period. It should be noted that a "stable advance interval" refers to an interval in which the phase advance rate change exhibits continuous consistency and can represent the dominant advance behavior within that period.

[0079] Within the stable propulsion interval only, the maximum, minimum and mean values ​​of the first-order phase propulsion rate are recalculated, and a range ratio parameter for judgment is constructed accordingly. At the same time, the mean square curvature parameter of the corresponding second-order phase propulsion rate change is calculated within the same interval.

[0080] Only when the number of sampling points covered by the stable propulsion interval is not less than a preset proportion of the number of effective sampling points in the phase period segment, the derivative statistical parameters obtained in the phase period segment are allowed to be used for the final determination of the phase propulsion effectiveness; if the stable propulsion interval is too short, it is considered that the phase propulsion behavior in the phase period segment is severely disturbed and lacks statistical representativeness, and therefore the effective phase propulsion determination is not performed on the period segment.

[0081] Step 5: Perform phase accumulation calculation only on the phase period segment that is determined to be effective phase advancement to obtain the effective displacement of the light-shielding sheet. It should be noted that the phase accumulation calculation is different from the direct phase superposition method based on the complete phase period in the existing technology. Its core is that the phase accumulation does not take the phase period itself as the smallest accumulation unit, but takes the "effective phase advancement interval after physical consistency determination" as the smallest reliable accumulation unit.

[0082] In the specific implementation process, after step 4 is completed, the system will generate a validity determination result for each phase period segment. When a phase period segment is determined to be a valid phase advance, the system will simultaneously retain the sampling index range of the identified stable advance interval within that phase period segment; when a phase period segment is not determined to be a valid phase advance, that period segment will be completely ignored in subsequent displacement calculations, and its corresponding unfolded phase data will no longer participate in any form of cumulative calculation.

[0083] For each phase period segment determined to be a valid phase advance, the system first extracts the unfolded phase value only within the stable advance interval corresponding to that period segment. Here, the "unfolded phase value" refers to the continuous phase data that has undergone phase unfolding processing in step 1 and period division in step 2, which maintains monotonic variation on the time axis.

[0084] Within the stable propulsion interval, the system uses the unfolded phase value corresponding to the starting sampling point of this interval as the phase accumulation reference within that phase period segment. Let the index of the starting sampling point of this stable propulsion interval be... The corresponding expansion phase is Then the reference phase is defined as the zero phase start point within that period segment.

[0085] It should be noted that this application uses the starting sampling point of the stable propagation interval as the reference benchmark, rather than directly using the starting point of the phase period segment. The reason is that the starting position of the phase period segment is determined by phase increment statistics and periodic conditions, and there may still be a phase instability region caused by optical interference or transient loading in its vicinity; while the stable propagation interval is the interval obtained under the joint constraints of the first and second derivatives, and its phase propagation behavior is closer to the actual translation state of the light shield.

[0086] After determining the reference benchmark, the system extracts the index of the sampling point at the end of the same stable propulsion interval. Corresponding expanded phase value Then, a differential operation is performed between this phase and the reference phase to obtain the effective phase increment corresponding to this phase period segment: in, Indicates the first The effective phase change corresponding to each effective phase period segment within its stable propulsion range. This phase change reflects the displacement process of the light-shielding plate within that period segment under physically stable propulsion conditions.

[0087] In implementation, if a stable propulsion interval is identified as multiple discontinuous sub-intervals within the same phase period segment, only the sub-interval with the largest number of covered sampling points is selected as the stable propulsion interval for that period segment to participate in phase accumulation calculation. As a possible implementation, the phase increments of multiple sub-intervals can also be calculated separately and then weighted and synthesized according to the system configuration, but this application does not limit the specific implementation form.

[0088] After the system completes the calculation of the effective phase increment for a single effective phase period segment, it will accumulate the effective phase increments obtained from multiple effective phase period segments in chronological order to form a cumulative phase quantity used to characterize the overall displacement of the light-shielding sheet: in, This represents the set of indices for all phase period segments determined to have valid phase advancement. It should be noted that the valid phase increments of different phase period segments in this application can be directly accumulated, provided that the phase increment within each phase period segment is obtained by differential calculation using the reference benchmark of that period segment within its respective stable advancement interval. This increment itself does not depend on the global phase reference point but only reflects relative displacement. Therefore, the phase increments between different period segments are physically superimposed.

[0089] For phase period segments that are not determined to be valid phase advances, their corresponding unfolded phase data will not have any impact on the accumulated phase in this embodiment. This "elimination-based accumulation" mechanism ensures that the system will not mistake unreliable phase changes for displacement when faced with local disturbances, abnormal loading, or optical noise, thereby avoiding the displacement drift problem common in traditional continuous phase accumulation schemes.

[0090] Step 6: Perform mass conversion based on the effective displacement and output the weighing result of the electronic balance. In this application, the effective displacement is a displacement characterization quantity obtained after multi-level processing, including effective phase advancement determination, stable advancement interval screening, and selective phase accumulation. Therefore, the mass conversion relationship corresponding to this effective displacement should also be established based on the same data generation mechanism.

[0091] In this embodiment, during the calibration phase of the electronic balance, the system first executes a displacement detection process that is completely consistent with the actual weighing process, including the contents described in steps 1 to 5. That is, during the calibration phase, no simplified or alternative displacement acquisition methods are used; instead, the effective displacement generation path to be used in the subsequent actual weighing is strictly adopted.

[0092] During the calibration process, multiple sets of known standard masses are sequentially loaded onto the weighing pan. After each set of standard masses is loaded and reaches a stable state, the system calculates the corresponding cumulative phase value using the method described in step 5, and converts the cumulative phase value into the corresponding effective displacement value. As one possible implementation, the effective displacement value can be converted using a pre-calibrated phase-displacement ratio coefficient, which is determined by the geometric parameters and optical structure of the micro-aperture array.

[0093] After obtaining multiple sets of correspondences between "standard mass and effective displacement", the system constructs a displacement-mass conversion relationship based on these data points. The conversion relationship can be established by linear fitting, polynomial fitting, or piecewise function fitting, etc. This application does not limit the specific fitting form, but requires that the established conversion relationship is based only on the effective displacement obtained by accumulating through effective phase advancement as described above.

[0094] It should be noted that this application specifically emphasizes that "the displacement-mass conversion relationship is established by the effective displacement amount." This is to avoid introducing displacement data containing invalid phase advances, abnormal phase fluctuations, or local disturbances into the mass model, which could lead to a shift in the model parameters themselves. In other words, the mass conversion relationship is not an abstract function independent of the displacement detection process, but rather forms a complete metrological link together with the displacement detection method.

[0095] In actual weighing, when the electronic balance receives a weighing request and detects an object to be measured on the weighing pan, the system executes the complete displacement detection process according to steps 1 to 5, ultimately obtaining the effective displacement under the current weighing state. Subsequently, the system only calls the displacement-mass conversion relationship established during the calibration phase and corresponding one-to-one with the effective displacement generation path to calculate the mass of the effective displacement.

[0096] In this embodiment, the system will not introduce any displacement information that has not undergone effective phase advance determination or has not passed the stable advance interval screening into the mass conversion process. Even in some extreme cases, if there is a large instantaneous phase change in the unfolded phase sequence, as long as the change is not determined as an effective phase advance in step 4, its corresponding displacement component will not affect the final weighing result.

[0097] It should be noted that the weighing result in this application refers to the output result calculated based on the effective displacement amount through a stable displacement-mass conversion relationship, and consistent with the actual displacement state of the light-shielding plate. This weighing result can be further processed by time averaging, stability assessment, or display refresh control before being output, but the above post-processing does not affect the core technical content of the displacement-mass conversion described in this application.

[0098] As one possible implementation, during the weighing process, the system outputs the corresponding mass value as the final weighing result only when it detects that the effective displacement has remained stable for a period of time; when the effective displacement is still changing, the output can be delayed or the display can be continuously updated to avoid the influence of transient processes on the weighing results.

[0099] Finally, it should be noted that the mathematical formulas, derivations, symbol definitions, and parameter calculation methods used in this specification are all for the purpose of further clarifying and verifying the technical content of this invention, so that those skilled in the art can more intuitively and accurately understand the working mechanism and technical effects of this invention. These formulas are only used as quantitative expressions or illustrative examples of technical features and do not constitute limiting conditions of the claims of this invention. Those skilled in the art should understand that, without changing the core idea of ​​this invention, the parameter forms, calculation methods, numerical ranges, and even symbol representations involved in the formulas can be equivalently replaced or simplified in engineering according to the actual application environment. The specifics can be determined according to the actual situation, and no limitation is imposed. It should also be emphasized that the formulas in this specification are not theoretical derivations in the style of academic research papers, but rather an engineering description of the embodiments of this invention. Their purpose is to enhance the understandability and implementability of this invention, rather than to increase redundancy and complexity. Those skilled in the art can choose whether to use such quantitative tools when reading this specification, or can achieve the same technical effects through other equivalent methods.

[0100] Furthermore, while specific embodiments of the present invention have been described above, those skilled in the art should understand that these specific embodiments are merely illustrative. Those skilled in the art can omit, substitute, and modify the details of the above methods and systems in various ways without departing from the principles and essence of the present invention. For example, combining the above method steps to perform substantially the same function and achieve substantially the same result according to substantially the same method falls within the scope of the present invention. Therefore, the scope of the present invention is defined only by the appended claims.

Claims

1. A method for detecting the displacement of a light-shielding plate in an electronic balance based on a micro-transmitting aperture array; characterized in that: Includes the following steps: Step 1: During the weighing process, continuously collect the moiré fringe light signal formed by the fixed micro-transmitting aperture array and the light-shielding sheet micro-transmitting aperture array, and obtain the corresponding continuous phase signal through orthogonal demodulation. Perform phase expansion on the continuous phase signal to obtain a monotonically changing expanded phase sequence. Step 2: Using the phase period corresponding to the moiré fringes as the segmentation benchmark, divide the unfolded phase sequence into multiple phase period segments, and establish a phase advancement curve in each phase period segment to show the phase change with the sampling sequence. Step 3: Calculate the first and second derivatives of the phase with respect to the sampling sequence for the phase advance curve within each phase period segment to obtain the phase advance rate distribution and the phase advance rate change distribution within that phase period segment; Step 4: When the difference between the maximum and minimum values ​​of the first derivative within the same phase period segment is less than a preset proportional threshold, the mean square value of the second derivative is less than a preset curvature threshold, and the change in the mean value of the first derivative of adjacent phase period segments is less than a preset continuity threshold, the corresponding phase advance is determined to be an effective phase advance. Step 5: Perform phase accumulation calculation only on the phase period segments that are determined to be effective phase advances to obtain the effective displacement of the light-shielding sheet; Step 6: Perform mass conversion based on the effective displacement and output the weighing result of the electronic balance.

2. The method for detecting the displacement of an electronic balance's light-shielding plate based on a micro-transmitting aperture array according to claim 1, characterized in that: The working process of step 1 includes: The in-phase and quadrature components of the moiré fringe optical signal are simultaneously demodulated to obtain two mutually orthogonal baseband signals. The instantaneous phase value is calculated based on two baseband signals, and the phase change between adjacent sampling points is compared point by point during continuous sampling. When the absolute value of the phase change exceeds the preset phase jump threshold, the phase change direction and the phase change trend of the previous and next sampling points are combined to determine whether the phase change corresponds to a real phase jump. When a true phase transition is determined, the instantaneous phase is compensated and unfolded to form a monotonically changing unfolded phase sequence, thus avoiding pseudo-phase jumps caused by local distortion of moiré fringe intensity or noise disturbance from participating in the phase unfolding process.

3. The method for detecting the displacement of the light-shielding plate of an electronic balance based on a micro-transmitting aperture array according to claim 1, characterized in that: Step 2, which involves dividing the unfolded phase sequence based on the phase period corresponding to the moiré fringes, includes: For the expanded phase sequence The calculation is performed by iterating through the samples in the order they were taken, and the phase increment is calculated between adjacent sample points. ,in, Indicates the index of the current sampling point; Within a sliding window containing L consecutive sampling points, the cumulative phase change is calculated for the phase increment. variance of phase increment The formula for calculating the cumulative phase change is: When the cumulative phase change satisfies Less than the preset phase closure tolerance threshold, and the phase increment variance satisfies When the value is less than the preset phase propulsion stability threshold, the corresponding sampling point will be... As the phase period boundary point, the unfolded phase sequence is divided into multiple consecutive phase period segments accordingly.

4. The method for detecting the displacement of the light-shielding plate of an electronic balance based on a micro-transmitting aperture array according to claim 1, characterized in that: The process of constructing the phase advancement curve includes: Indexed by the starting sampling point of the phase period segment Using the sampled points as reference points, the expanded phase values ​​corresponding to each sampling point within the period are normalized to obtain the phase advancement sequence within the period. Based on the phase-propelling sequence, a corresponding continuous phase-propelling model is constructed through least-squares fitting, with the expression: in, This represents the first-order phase advance coefficient within that phase period. This represents the second-order phase propulsion correction coefficient. This represents the phase-driven residual term. Indicates the first Phase progression curves showing how the phase changes with the sampling sequence within a single phase period.

5. The method for detecting the displacement of an electronic balance's light-shielding plate based on a micro-transmitting aperture array according to claim 1, characterized in that: The working process of step 3 includes: In the Within each phase period segment, the phase advancement curve constructed within that period segment For the calculation object, select a sampling index interval that covers the phase period segment. Within the sampling index interval, the phase advancement curve is segmented using a sliding sampling window of fixed length; Within each sliding sampling window, the phase advancement data within the window is locally and continuously fitted using the polynomial least squares fitting method to obtain the corresponding local phase function. Based on the local phase function, the first-order phase derivative and the second-order phase derivative at the sampling point at the center of the window are calculated respectively. The sliding sampling window is moved point by point along the sampling sequence direction, and the above local fitting and differentiation process is repeated to form a phase advance rate distribution sequence composed of multiple first-order derivative values ​​and a phase advance rate change distribution sequence composed of multiple second-order derivative values ​​within the entire phase period segment. Each derivative value corresponds one-to-one with the position of the corresponding sampling point within the phase period segment.

6. The method for detecting the displacement of the light-shielding plate of an electronic balance based on a micro-transmitting aperture array according to claim 5, characterized in that: Step 3, in the process of forming the phase advance rate distribution sequence and the phase advance rate change distribution sequence within the phase period segment, further includes: In the Within each phase period segment, the first-order phase advance rate distribution sequence obtained by the sliding sampling window and the distribution sequence of second-order phase propulsion rate changes A joint continuity constraint is constructed according to the sampling sequence order, so that the derivative distribution satisfies the consistency of displacement evolution within the same phase period segment; The joint continuity constraint condition includes at least the following: the change in the first-order phase advance rate at adjacent sampling points satisfies The second-order phase advance rate change satisfies the sign consistency constraint within the phase period segment. ,in, Indicates the first Sampling points within each phase period segment The first-order phase propulsion rate at that point, This represents the change in the second-order phase propagation rate at the corresponding sampling point. A continuity threshold is set to limit the variation of the phase advance rate between adjacent sampling points; The derivative values ​​that satisfy the above joint continuity constraints are retained in the corresponding phase advance rate distribution sequence and phase advance rate change distribution sequence.

7. The method for detecting the displacement of an electronic balance's light-shielding plate based on a micro-transmitting aperture array according to claim 1, characterized in that: Step 4 further includes performing joint normalization and consistency verification on the multidimensional derivative criterion within the phase period segment, the process of which is as follows: In the Within a phase period segment, based on the first-order phase propulsion rate distribution sequence of that period segment and the distribution sequence of second-order phase propulsion rate changes Calculate the range ratio parameter of the first-order phase propulsion rate respectively. Mean square curvature parameters of the second-order phase propulsion rate change The calculation formulas are as follows: in, Indicates the first The average first-order phase advance rate within each phase period segment. This indicates the number of valid sampling points within the phase period segment; For adjacent phase period segments and Calculation of the mean first-order phase propulsion rate across periods The calculation formula is: When the range ratio parameter Mean square curvature parameter and cross-cycle change When all three types of parameters simultaneously satisfy their respective preset constraints and are constructed based on the effective derivative distribution within the same phase period segment during the calculation process, the phase advance corresponding to that phase period segment is determined to be an effective phase advance; wherein, the preset constraints correspond to the intra-period consistency of the phase advance rate, the overall stability of the phase advance curvature, and the continuous evolution characteristics of the phase advance between adjacent period segments.

8. The method for detecting the displacement of the light-shielding plate of an electronic balance based on a micro-transmitting aperture array according to claim 1, characterized in that: The determination of effective phase advance in step 4 is based on the stable advance interval within the phase period segment, specifically including: In the Within a phase period segment, based on the first-order phase propulsion rate distribution sequence of that period segment The set of sampling points that satisfy the continuity constraint of phase advance rate change is identified according to the sampling sequence, and the part that forms a continuous sampling interval is determined as the stable advance interval within the phase period segment. Within the stable propulsion interval, the maximum, minimum, and mean values ​​of the first-order phase propulsion rate are calculated respectively, and the first-order derivative statistical parameters for judgment are constructed accordingly. At the same time, the mean square value of the corresponding second-order phase propulsion rate change is calculated within the same interval. When the number of sampling points covered by the stable propulsion interval is not less than a preset proportion of the number of effective sampling points in the phase period segment, the derivative statistical parameters obtained in the phase period segment are allowed to be used to determine the effectiveness of phase propulsion; otherwise, the effective phase propulsion determination is not performed for the phase period segment.

9. The method for detecting the displacement of the light-shielding plate of an electronic balance based on a micro-transmitting aperture array according to claim 1, characterized in that: The phase accumulation calculation process includes: For each phase period segment that is determined to be a valid phase advance, the unfolded phase value is extracted only within the stable advance interval corresponding to that phase period segment, and the unfolded phase corresponding to the starting sampling point of that stable advance interval is used as the reference benchmark for phase accumulation within the period. Within the stable propulsion range, the unfolded phase corresponding to the end sampling point is subtracted from the reference reference to obtain the effective phase increment corresponding to the phase period segment; The effective phase increments obtained from multiple effective phase period segments are accumulated in chronological order to form a cumulative phase quantity used to characterize the effective displacement of the light-shielding sheet.

10. The method for detecting the displacement of the light-shielding plate of an electronic balance based on a micro-transmitting aperture array according to claim 1, characterized in that: The process of step 6 includes: The cumulative phase quantity obtained in step 5 is converted into the corresponding effective displacement quantity, and the displacement mass conversion relationship corresponding to the path is generated based on the effective displacement quantity to perform mass calculation. The displacement mass conversion relationship is established by fitting the effective displacement quantity corresponding to multiple sets of known standard masses during the calibration process of the electronic balance. In the actual weighing process, only the effective displacement amount obtained based on the effective phase advancement accumulation is used in the displacement-mass conversion calculation, thereby outputting a weighing result that corresponds one-to-one with the effective displacement amount.

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