Cross control line based tower shaft kiln masonry laser measurement and control system

Abstract

The application belongs to the technical field of construction surveying, and discloses a tower type shaft kiln masonry laser measurement and control system based on cross control lines; by acquiring temperature field distribution and dust concentration data on the laser propagation path, a refraction offset and scattering attenuation double compensation mechanism is constructed to realize accurate measurement of the central point coordinates and high-precision establishment of the four-directional basic measurement and control line group; the application takes the deformation modal extreme position corresponding to each harmonic component as the basis for blind area judgment through the use of an intelligent blind area recognition mechanism, and through adaptive supplementary measurement and control lines and minimum area circle fitting operation, the masonry correction instruction is accurately evaluated and generated; the application also establishes a layered circle center coordinate vertical sequence, identifies the systematic trend deviation in combination with the circular statistical method, triggers the reference re-measurement process, and effectively prevents and controls the cumulative error; the application has comprehensiveness and accuracy, can perform full-link measurement and control and quality evaluation on the shaft kiln masonry process, and effectively ensures that the kiln body perpendicularity and roundness meet the design requirements.

Description

Technical Field

[0001] This invention relates to the field of construction surveying technology, and more specifically, to a laser measurement and control system for tower-type vertical kiln masonry based on cross control lines. Background Technology

[0002] Existing vertical kiln construction measurement and control technologies generally lack end-to-end error compensation and intelligent adaptive measurement and control mechanisms for complex industrial environments, making it difficult to reliably guarantee construction accuracy under harsh conditions such as high temperatures and high dust levels. Specifically, traditional measurement and control methods rely solely on the direct projection results of laser plumb bobs, ignoring the systematic deviations caused by the non-uniform distribution of the temperature field and changes in dust concentration during laser beam propagation. In actual construction, when the internal temperature gradient of the vertical kiln is significant and the dust concentration is high, the refraction shift of the laser spot and the energy scattering distortion are often superimposed simultaneously, forming a "black box" of measurement accuracy. For example, during the construction of a tower-type vertical kiln with a height exceeding 30 meters, after the laser beam is refracted and accumulated by multiple layers of hot airflow, the projection point on the working surface may experience a systematic shift on the order of centimeters. Existing technologies cannot quantitatively assess the refraction shift caused by the temperature field, nor can they adaptively select a spot center identification strategy based on the degree of dust scattering, and there is no way to collaboratively compensate and correct these two types of errors. The lack of this compensation mechanism means that the measurement and control system can only provide nominal center coordinates, rather than accurate measurement results in a true sense, which seriously restricts the reliability of vertical kiln verticality control.

[0003] In view of this, the present invention proposes a laser measurement and control system for tower vertical kiln masonry based on cross control lines to solve the above problems. Summary of the Invention

[0004] To overcome the aforementioned deficiencies of the prior art and to achieve the above objectives, the present invention provides the following technical solution:

[0005] A laser measurement and control system for tower-type vertical kiln masonry based on cross-shaped control lines includes:

[0006] The parameter compensation acquisition module is used to obtain the three-dimensional spatial coordinates of the permanent reference center point at the bottom of the tower vertical kiln. The vertical laser projection channel established at the permanent reference center point projects the vertical center point to the current masonry working face, and calculates the refraction offset and scattering attenuation coefficient based on the air temperature field distribution and dust concentration distribution on the laser beam propagation path during the projection process.

[0007] The control line group construction module performs dual correction on the projection landing point coordinates based on the refraction offset and scattering attenuation coefficient to obtain the corrected center point coordinates, and establishes a four-directional basic control line group on the masonry working surface with the corrected center point coordinates as the origin.

[0008] The deviation dimension measurement module uses a high-precision total station to perform radial linear dimension measurement on the four-direction basic control line group, obtains the measured radius values ​​in the four directions, compares them with the design radius values, and obtains the radial deviation vector in the four directions.

[0009] The blind zone intelligent identification module identifies and determines blind zones based on four-direction radial deviation vectors. If a detection blind zone is determined, a supplementary control line is established between adjacent basic control lines. The supplementary control line is then used to measure the radial linear dimensions to obtain a complete radial measurement dataset in eight directions.

[0010] The roundness profile fitting module performs roundness profile fitting calculations based on the complete radial measurement dataset in eight directions to obtain the roundness error value and center offset vector of the cylinder cross section. It determines whether the cylinder meets the design roundness requirements based on the roundness error value and generates masonry correction instructions based on the center offset vector.

[0011] The cumulative error monitoring module is used to monitor the radius verification data and center coordinates of each masonry layer in real time during the masonry correction process, establish a vertical sequence of layered center coordinates, and determine whether to trigger the operation process of re-introducing the permanent reference center point at the bottom based on the vertical sequence of layered center coordinates.

[0012] The technical effects and advantages of the laser measurement and control system for tower vertical kiln masonry based on cross-shaped control lines of this invention are as follows:

[0013] 1. By establishing a dual environmental parameter compensation mechanism based on temperature field and dust concentration, this invention can effectively eliminate the superimposed effects of refraction offset and scattering distortion during laser propagation, accurately restore the true vertical projection position of the bottom permanent reference center point on the current masonry working surface, and fundamentally ensure the reliability and accuracy of laser measurement under high temperature and high dust conditions.

[0014] 2. This invention introduces a blind zone intelligent identification mechanism based on harmonic decomposition, which can quantitatively predict the extreme orientation of higher-order deformation modes such as ellipticization and triangulation, adaptively trigger the establishment of supplementary measurement and control lines, effectively eliminate the measurement blind zone of the fixed four-direction layout scheme, ensure that the deformation characteristics of the cylinder cross section are fully captured, and significantly improve the accuracy and reliability of the roundness evaluation results.

[0015] 3. This invention, through minimum area circle fitting operation and quantitative calculation of circle center offset vector, can accurately generate structured masonry correction instructions containing correction direction, single-layer correction amount and correction layer number, effectively guiding on-site construction personnel to perform layered and gradual correction, avoiding masonry turning too sharply and causing structural stress concentration, and effectively ensuring that the verticality of the kiln body meets the design requirements.

[0016] 4. This invention provides a systematic technical foundation for the full-link controllability and traceability of the accuracy of tower kiln construction by constructing a complete closed-loop measurement and control system, from benchmark establishment, environmental compensation, measurement and control line layout, blind spot identification, roundness evaluation to correction guidance. This effectively improves the digital management and control level and engineering quality assurance capability of industrial kiln construction. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the laser measurement and control system for tower-type vertical kiln masonry based on cross control lines according to the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1

[0020] Please see Figure 1 As shown, this embodiment provides a laser measurement and control system for tower-type vertical kiln masonry based on cross-shaped control lines, including:

[0021] The parameter compensation acquisition module is used to obtain the three-dimensional spatial coordinates of the permanent reference center point at the bottom of the tower-type vertical kiln. These three-dimensional spatial coordinates serve as the spatial reference for establishing the entire verticality control system of the vertical kiln. Precise determination of the reference point is achieved in the early stages of construction using high-precision measuring equipment. The permanent reference center point is set on a stable foundation at the bottom of the vertical kiln and is physically calibrated using pre-embedded metal markers or optical targets. Its coordinates include both planar and elevation components, possessing uniqueness and traceability within the overall engineering coordinate system. A vertical laser projection channel established at the permanent reference center point projects the vertical center point onto the current masonry working face. This vertical laser projection channel is the core technology for achieving layer-by-layer center point measurement. A laser plumb line emits a vertically upward laser beam at the reference point, requiring the upward projection point to be ≤1 / 40000 to meet the high precision requirements of the kiln body. The projection channel forms a theoretical vertical line in physical space. The laser beam propagates upward along the channel to the current masonry working face, forming a light spot on the working face. The center of this light spot is theoretically the vertical center point at that elevation. The refractive offset and scattering attenuation coefficient were calculated based on the air temperature field distribution and dust concentration distribution along the laser beam propagation path during the projection process. The refractive offset and scattering attenuation coefficient are key parameters for quantitatively describing the influence of environmental factors on laser propagation. They were obtained through real-time monitoring and numerical calculation using a distributed sensor network. The non-uniform distribution of the air temperature field leads to spatial differences in the air refractive index. The laser beam undergoes continuous refraction during propagation, and the cumulative effect causes the spot position to deviate from the theoretical center point. Changes in dust concentration cause scattering loss of laser energy, reducing the clarity and energy concentration of the spot, and affecting the accuracy of center identification.

[0022] The control line group construction module performs dual correction on the projection landing point coordinates based on refraction offset and scattering attenuation coefficient to obtain the corrected center point coordinates. Scattering attenuation compensation assesses the degree of energy distribution distortion of the light spot based on the scattering attenuation coefficient. Refraction offset compensation performs reverse position correction on the identified center coordinates based on refraction offset. The dual correction mechanism comprehensively considers the energy characteristics and geometric characteristics of laser propagation to ensure that the corrected center point coordinates can accurately reflect the vertical projection position of the bottom reference center point at the current elevation. A four-directional foundation control line group is established on the masonry working surface with the corrected center point coordinates as the origin, including four control lines pointing to the four reference directions of 0°, 90°, 180°, and 270°. The control lines extend outward from the corrected center point to the design radius and are physically calibrated using metal wires or laser lines. The quality of the establishment of the four-directional control line group directly affects the accuracy of blind zone identification and roundness assessment.

[0023] The deviation dimension measurement module, based on a high-precision total station, performs radial linear dimension measurement on the four-direction basic control line group to obtain the measured radius values ​​in the four directions. These measured radius values ​​are then compared with the design radius values ​​to obtain the four-direction radial deviation vectors. The total station is set up at the correction center point or other known measurement stations, and accurately determines the spatial coordinates of the endpoints of each control line using distance and angle measurement functions. For the case where the correction center point is the measurement station, the distance value is the measured radius value. For measurements at different stations, the measured radius value is obtained through coordinate inverse calculation. The radial deviation vector is a vector parameter that quantitatively describes the masonry deviation, calculated by the difference between the measured value and the design value. The comparison process first extracts the design radius value of the current masonry layer from the design drawings or database; then, it calculates the deviation value in each direction. A positive deviation value indicates that the actual radius is greater than the design radius, resulting in outward convex masonry; a negative deviation value indicates that the actual radius is less than the design radius, resulting in inward concavity. The four deviation values ​​and their corresponding azimuth angles constitute the four-direction radial deviation vector set, which serves as the data source for subsequent blind zone identification and deformation mode analysis.

[0024] The blind zone intelligent identification module identifies blind zones based on four-directional radial deviation vectors. The identification process involves harmonic decomposition of the radial deviation vectors in the frequency domain, extracting harmonic components of different orders. The second harmonic corresponds to elliptic deformation, with its extreme values ​​located along the major and minor axes. The first harmonic corresponds to overall eccentricity, with its extreme values ​​located in the eccentric direction. The third harmonic corresponds to triangular deformation, with extreme values ​​distributed at 120° intervals. By identifying the type and amplitude of the dominant harmonics, the module predicts the possible azimuth angles of deformation extreme values. The expected extreme value locations are compared with the azimuth angles of existing four-directional control lines, and the comparison results determine whether a detection blind zone exists, indicating that the deformation extreme value may be located in an unmeasured area, and that the four-directional data cannot fully reflect the true deformation state of the cylinder.

[0025] If a detection blind zone is identified, supplementary control lines are established between adjacent basic control lines. The triggering process intelligently determines the number and orientation of supplementary control lines based on the distribution characteristics of the sensitive azimuth angles of the blind zone. In standard mode, control lines are added in four directions: 45°, 135°, 225°, and 315°, forming a standard eight-direction control network with the original four directions. In adaptive mode, the supplementary directions are dynamically determined based on the extreme azimuth angles of the dominant deformation mode, ensuring that the measuring points accurately cover key deformation locations. The establishment process of supplementary control lines is the same as that of basic control lines. Radial linear dimension measurement is performed on the supplementary control lines to obtain a complete eight-direction radial measurement dataset. This dataset is a high-density data sample comprehensively describing the deformation characteristics of the cylinder cross-section. During the measurement process, polar coordinate measurements are performed on the endpoint markers of the supplementary control lines to obtain the measured radius and measured azimuth angle of the supplementary directions. This data is then merged with the original four-direction data to form a radial measurement dataset containing eight or more directions. This complete dataset provides sufficient data support for subsequent roundness profile fitting, ensuring the accuracy and reliability of the fitting results.

[0026] The roundness profile fitting module performs roundness profile fitting calculations based on the complete eight-direction radial measurement dataset to obtain the roundness error value and center offset vector of the cylinder cross-section. It determines whether the cylinder meets the design roundness requirements based on the roundness error value and generates masonry correction instructions based on the center offset vector. The fitting process first converts the radial measurement data in polar coordinates into a two-dimensional coordinate point set in Cartesian coordinates, forming a discrete profile point cloud. Then, it uses a minimum region circle evaluation algorithm to search for two concentric inner and outer circles, ensuring that all profile points fall between the two circles with the minimum annular width, which is the roundness error value. Simultaneously, it obtains the center coordinates of the best-fit circle and calculates the difference between them and the correction center point coordinates to obtain the center offset vector. The roundness error value reflects the roundness of the cylinder cross-section and is a direct basis for judging whether the masonry quality meets the design requirements; the center offset vector reflects the spatial position deviation of the cylinder axis and is the core parameter for generating masonry correction instructions. The judgment process extracts the allowable roundness deviation value from the design specifications or technical requirements; compares the measured roundness error value with the allowable deviation value; if the roundness error value is not greater than the allowable value, it is judged as qualified, and the masonry layer meets the design roundness requirements, and masonry can continue upward; if the roundness error value exceeds the allowable value, it is judged as unqualified, and masonry rework or roundness correction measures are required. Next, the magnitude and direction angle of the center offset vector are extracted. The magnitude represents the correction amount, and the direction angle represents the correction direction; when the magnitude of the offset vector is greater than the correction initiation threshold, it is judged that masonry correction is required; then, a layered correction strategy is formulated according to the magnitude of the correction amount. When the offset is small, single-layer correction is used, and the correction is carried out all at once in the next layer of masonry; when the offset is large, layered progressive correction is used, and the correction is carried out gradually in subsequent layers to avoid the masonry turning too sharply, which would cause structural stress concentration. The correction instruction includes detailed information such as correction direction, single-layer correction amount, number of correction layers, and verification requirements.

[0027] The cumulative error monitoring module is used during the masonry correction process to establish a vertical sequence of center coordinates for each layer by real-time monitoring of the radius verification data and center coordinates of each masonry layer. Based on this sequence, it determines whether to trigger the re-measurement of the permanent baseline center point at the bottom. The establishment process involves performing a complete measurement and center fitting procedure after each masonry layer is completed to obtain the plane coordinates of the center of that layer. Combined with the vertical elevation coordinates of that layer, a single-layer center coordinate data record containing three-dimensional information is formed. The data for each layer is sorted by elevation from low to high to form a vertical sequence. This vertical sequence not only records the center position of each layer but also implicitly includes the spatial curve characteristics, offset trends, and cumulative patterns of the axis. The judgment process involves fitting a straight line in three-dimensional space to the vertical sequence to obtain the best-fit axis; calculating the vertical distance from the center coordinates of each layer to the fitted axis to obtain the straightness deviation; when the straightness deviation exceeds the threshold, further analyzing the azimuth distribution of the offset vector; calculating the circumferential mean and standard deviation of the azimuth angle to identify a systematic trend offset; when a systematic offset is confirmed and the cumulative offset continues to increase with elevation, it is determined that there may be a benchmark offset or equipment systematic error, triggering the operation process of re-measurement of the permanent benchmark center point at the bottom, eliminating the cumulative deviation through recalibration, and restoring the accuracy of the measurement benchmark.

[0028] In embodiments of the present invention, the detailed implementation steps for calculating the refraction offset and the scattering attenuation coefficient include:

[0029] Multiple temperature monitoring sections are uniformly spaced vertically along the laser beam propagation path. Specifically, the setup process first determines the total length of the laser beam propagation path, i.e., the vertical distance from the bottom reference point to the current masonry working surface; then, based on the spatial variation characteristics of the temperature field and the monitoring accuracy requirements, the vertical spacing of the monitoring sections is determined; multiple horizontal sections are set at equal intervals vertically, each section being perpendicular to the laser beam axis; the number of monitoring sections is dynamically adjusted according to the height of the vertical kiln, with more sections for greater height to ensure the completeness of the temperature field description.

[0030] Each temperature monitoring section contains multiple temperature measuring points radially distributed around the laser beam axis. Specifically, the deployment process involves placing multiple temperature sensors radially outward from the point where the laser beam passes through the section on each monitoring section; the coverage area must extend beyond the inner diameter of the cylinder to ensure that the temperature boundary effect inside the cylinder can be monitored; simultaneously, multiple directions are arranged in the circumferential direction to form a star-shaped or grid-like distribution pattern of measuring points; the number of measuring points in each section is determined based on the cylinder diameter and the complexity of the temperature gradient; the measuring points use high-precision digital temperature sensors.

[0031] The spatial temperature field distribution is obtained by collecting data at temperature measurement points and performing three-dimensional Kriging space interpolation. Specifically, the interpolation process first collects the measured temperature values ​​of all temperature measurement points on the monitoring cross-section, forming a discrete dataset containing spatial coordinates and temperature values; then, a temperature spatial variogram is constructed to describe the correlation decay law of temperature at different spatial distances, and a theoretical variogram model is obtained by fitting the experimental variogram; next, based on the Kriging equations, the temperature at any location in space is estimated, and the estimated value is a weighted average of the temperatures of surrounding measurement points, with the weighting coefficients determined by the variogram and the spatial positional relationship of the measurement points; finally, batch interpolation is performed on a three-dimensional spatial grid to generate a continuous temperature field distribution covering the entire laser propagation path area; the spatial temperature field distribution is stored in the form of a three-dimensional scalar field, providing a complete temperature data foundation for subsequent refractive index calculation and refractive shift analysis.

[0032] Based on the atmospheric stratification and refraction theory, the average temperature value at each temperature monitoring section is extracted by combining the spatial temperature field distribution. Specifically, the interpolated temperature field value within each temperature monitoring section is read during the extraction process; spatial averaging is performed within the effective influence area of ​​the laser beam within the section (usually within three times the beam radius), and the temperature integral is calculated and divided by the area of ​​the region to obtain the average temperature value of the section; the average temperature value eliminates the influence of local temperature fluctuations and represents the overall temperature level of the laser propagation environment at that elevation, serving as the input parameter for calculating the refractive index of that air layer.

[0033] Calculate the refractive index of air at each temperature monitoring section. Specifically, the calculation process uses the Edlund formula or the Couch formula to calculate the air refractive index based on the average temperature, atmospheric pressure, and relative humidity of the section. For lasers in the visible light band, the relationship between refractive index and temperature can be approximately expressed as: ;in, The refractive index of air, Atmospheric pressure (unit: Pa). The absolute temperature (unit: K) is used to calculate the air refractive index at each temperature monitoring section by converting the average temperature value of the cross section into absolute temperature and combining it with the on-site air pressure measurement value. The small difference in refractive index causes a continuous deflection of the direction of light propagation, which is the physical basis for the calculation of refraction offset.

[0034] The laser propagation path between adjacent temperature monitoring sections is considered as a tiny refractive segment. Specifically, the partitioning process divides the entire laser propagation path into multiple interconnected refractive segments along the temperature monitoring sections; the starting and ending points of each refractive segment are located on two adjacent temperature monitoring sections, and the segment length is equal to the distance between the sections; within a single refractive segment, it is assumed that the air refractive index is uniform, equal to the arithmetic or geometric mean of the refractive indices of the starting and ending sections; this simplifies the complex continuous refraction problem while ensuring that the discretization error remains within an acceptable range through sufficiently small segment lengths.

[0035] The cumulative refraction angle of the laser beam along its entire propagation path is calculated segment by segment using a piecewise integration method. Specifically, for each refraction segment, Snell's law is applied to calculate the refraction angle at the segment boundary based on the refractive index difference between the two ends of the segment and the segment length. For small refraction angles, the refraction angle can be approximated as: ;in, For the first The angle of refraction of the segment, For the section chief, and The refractive index of adjacent sections is used; then the refraction angles of all refraction sections are summed to obtain the cumulative refraction angle. ,in The total number of refractive segments; the cumulative refraction angle quantifies the overall deflection of the laser beam caused by the temperature field and is a key intermediate parameter for calculating the horizontal plane offset.

[0036] The orthogonal projection length of the product of the cumulative refraction angle and the total propagation length of the laser beam onto the working plane is used as the refraction offset. Specifically, the calculation process first obtains the total propagation length H of the laser beam, i.e., the vertical distance from the reference point to the working plane; then, it calculates the horizontal displacement of the beam endpoint caused by the cumulative refraction angle, approximately as follows: Next, the direction of the refraction offset is determined. By analyzing the refraction direction of each refraction segment and performing vector synthesis, the azimuth angle of the offset is obtained. Finally, the horizontal displacement vector is projected onto the coordinate system of the working surface to obtain the eastward and northward refraction offset components. The typical value of the refraction offset is on the order of millimeters to centimeters. Although relatively small, it has a significant impact on high-precision measurements and requires accurate compensation.

[0037] Laser scattering dust concentration sensors are installed at the starting point, quarter point, midpoint, three-quarter point, and ending point of the laser beam propagation path. Specifically, the setup process first determines the total propagation path length H, and calculates the elevation positions of each feature point as 0, H / 4, H / 2, 3H / 4, and H, respectively. Laser scattering dust concentration sensors are then installed at the corresponding elevation positions. This five-point deployment balances comprehensive monitoring with cost-effectiveness, enabling the capture of dust concentration differences at different heights (bottom, middle, and top), providing sufficient data support for fitting the concentration distribution function.

[0038] Five measured dust concentration values ​​were acquired, and a continuous vertical distribution function of dust concentration was fitted using spline interpolation. Specifically, the fitting process first read the real-time dust concentration measurements from five sensors, forming an elevation-concentration data set; then, a piecewise cubic polynomial function was constructed using a cubic spline interpolation algorithm, ensuring that the function accurately passes through the measured values ​​at the data points, smoothly transitions between data points, and has continuous first and second derivatives; finally, a continuous function of dust concentration with respect to elevation was obtained; dust concentration estimates can be calculated at any elevation, providing continuous concentration input for path integral calculation of the scattering attenuation coefficient.

[0039] The local scattering attenuation coefficient of the laser beam in different path segments is calculated based on a continuous distribution function and pre-stored dust particle size distribution parameters from the construction environment. Specifically, the calculation process first extracts dust particle size distribution parameters from the construction environment database, including the median particle size, particle size range, and distribution function type (e.g., log-normal distribution); then, the laser propagation path is divided into multiple small path segments, typically 1-2 meters in length; for each path segment, the dust concentration at the midpoint elevation of the segment is calculated. Next, based on Mie scattering theory, the scattering cross section and extinction coefficient under these concentration and particle size distribution conditions are calculated; the local scattering attenuation coefficient is also calculated. Defined as the proportion of energy attenuation per unit length of path, the calculation formula is: Where k is a constant coefficient, The extinction efficiency factor is determined by the particle size distribution and the laser wavelength; the local scattering attenuation coefficients of each path segment form a spatial distribution sequence, providing segmented data for the overall attenuation calculation.

[0040] The scattering attenuation coefficient is obtained by exponentially accumulating the local scattering attenuation coefficients of each path segment. Specifically, the accumulation process is based on the exponential law of light intensity attenuation, and the change of laser intensity with propagation distance satisfies... In the formula, The intensity of the laser after propagation. Initial laser intensity; Let be the local scattering coefficient of the i-th segment; for non-uniform media, the piecewise exponential accumulation method is used, and the emitted light intensity of the i-th segment is denoted as . ; Calculate step by step, the ratio of the final light intensity to the initial light intensity is Define the scattering attenuation coefficient. , representing the equivalent total optical path attenuation. The larger the scattering attenuation coefficient, the lower the energy concentration of the light spot, the more blurred the edges, and the more significant the impact on the accuracy of center recognition. It is a key criterion for selecting a light spot center recognition algorithm.

[0041] In embodiments of the present invention, the detailed implementation steps for performing dual corrections include:

[0042] The degree of energy distribution distortion of a laser spot is assessed based on the scattering attenuation coefficient. Specifically, the assessment process first sets a grading threshold for the scattering attenuation coefficient, typically divided into three levels: low attenuation, medium attenuation, and high attenuation. Then, the calculated scattering attenuation coefficient determines its level. Low attenuation corresponds to slight distortion, with clear spot edges and concentrated energy; high attenuation corresponds to severe distortion, with diffused spot edges, dispersed energy, and a blurred center. Accurate assessment of the distortion degree provides a basis for subsequent selection of an appropriate center identification method, ensuring reliable extraction of the spot center under different environmental conditions.

[0043] When the energy distribution distortion exceeds a preset distortion threshold, high-resolution images of the laser spot are acquired. Specifically, a high-resolution industrial camera is mounted above the masonry work surface, with the lens vertically downwards aimed at the laser spot area. By adjusting the exposure time and aperture, it is ensured that the main part of the laser spot is not overexposed, while the edge parts have a sufficient signal-to-noise ratio. The acquired images are stored in grayscale or color format, with the grayscale or brightness value of each pixel reflecting the laser energy density at that location. The high-resolution images provide high-quality data input for subsequent centroid recognition algorithms.

[0044] The centroid coordinates of the light spot are identified and used as preliminary correction coordinates. Specifically, the identification process first preprocesses the acquired light spot image, including noise reduction filtering, background subtraction, and threshold segmentation, to extract the effective pixel set of the light spot region; then, the centroid coordinates are calculated; finally, they are converted into actual coordinates of the working surface. The conversion process uses camera calibration parameters for distortion correction and scaling to obtain the preliminary correction coordinates of the light spot centroid.

[0045] When the energy distribution distortion is no greater than a preset distortion threshold, the coordinates of the geometric center of the laser spot are used as the initial correction coordinates. Specifically, the acquisition process involves edge detection of the spot image, using the Canny algorithm or threshold segmentation to extract the outer contour of the spot; then, the contour is fitted as an ellipse or a circle, and the center coordinates of the best-fit shape are calculated using the least squares method; for example, for an ideal circular spot, the geometric center is the center of the circle; for a slightly elliptical spot, the geometric center is the center of the ellipse. The geometric center recognition algorithm has high computational efficiency and its accuracy is comparable to the centroid method under low distortion conditions, so it is preferred when scattering attenuation is small, saving computational resources.

[0046] Position compensation is applied to the initial corrected coordinates in the opposite direction of the refraction offset to obtain the coordinates of the corrected center point. Specifically, the compensation process first extracts the eastward component of the previously calculated refraction offset. and northward component Then, the initial corrected coordinates are applied in reverse. The physical meaning of applying in reverse is that the observed spot position is the position of the true center point after refraction. The true center point position can be restored by reverse translation. After compensation, the corrected center point coordinates are obtained. These coordinates eliminate the dual effects of temperature refraction and dust scattering and are the true vertical projection position of the bottom reference center point at the current elevation.

[0047] The standard deviation of the corrected center point coordinates is calculated by repeatedly measuring within a preset time interval. The standard deviation of repeated measurements is a statistical indicator for evaluating the stability and reliability of the correction results, obtained through time series analysis. The measurement process involves multiple independent measurements within a preset time interval (usually 1-3 minutes). Each measurement fully executes the entire process of image acquisition, center identification, and refraction offset compensation, resulting in a set of corrected center point coordinates. The number of measurements is typically 5-10 to ensure the validity of the statistical analysis. Then, the standard deviations of the eastward and northward coordinates are calculated. The standard deviation quantifies the dispersion of the measurements and is a key indicator for judging the effectiveness of the correction.

[0048] When the standard deviation is less than the preset stability threshold, the correction is confirmed to be effective, and the average of multiple measured coordinates is used as the final corrected center point coordinates. Specifically, the judgment process compares the calculated eastward and northward standard deviations with the preset stability threshold (usually 1-2 mm). When the standard deviations in both directions are less than the threshold, it indicates that the repeated measurement results are highly consistent, the random error is small, the correction method is effective and reliable, and the correction is confirmed to be effective. Otherwise, the correction is determined to be unstable, which may be due to environmental disturbances, equipment drift, or algorithm abnormalities, requiring re-examination and adjustment. After confirmation of effectiveness, the arithmetic mean of multiple measured coordinates is calculated as the final corrected center point coordinates. The use of the average value improves the accuracy and reliability of the center point coordinates, providing an accurate origin benchmark for the subsequent establishment of the control line.

[0049] In an embodiment of the present invention, the detailed implementation steps for establishing a four-directional basic measurement and control line group include:

[0050] A coordinate system is established on the current masonry work surface with the final correction center point as the center. The work surface coordinate system serves as a local reference frame for orientation and dimensional measurement, established with the correction center point as the origin. The establishment process begins with physically marking the final correction center point on the work surface using methods such as crosshairs, metal markers, or optical targets, ensuring the mark is clear and identifiable. Then, a Cartesian coordinate system is established with this point as the origin, with the coordinate axes aligned with the overall engineering coordinate system: the X-axis points east, the Y-axis points north, and the Z-axis is vertically upward. The centering and leveling of the measuring instruments are then performed to ensure precise alignment between the instrument's measuring station and the correction center point. The establishment of the work surface coordinate system provides a unified reference benchmark for subsequent azimuth and radial measurements, ensuring the accuracy of the orientation of each control line.

[0051] The center point of the masonry workface is used as the survey station, combined with the azimuth reference north of the overall kiln design coordinate system. The north reference azimuth is the angular starting point for calculating the azimuth of the orientation control line, obtained through alignment with the overall coordinate system. The determination process first extracts the definition of the north direction of the design coordinate system from the overall kiln design documents. This direction may be true north, magnetic north, or coordinate north, determined according to engineering conventions. Then, a laser theodolite or total station is set up at the survey station, and the azimuth reference of the instrument in the overall coordinate system is determined through methods such as resection, direction observation, or GNSS orientation. For existing control points, orientation is performed by observing the control direction with a known azimuth. For independent coordinate systems, true north is determined using a gyro theodolite or astronomical observation. After orientation, the 0° direction of the instrument is aligned with the north reference azimuth, providing an accurate angular starting point for subsequent four-direction surveying.

[0052] Based on the true north reference azimuth, radial laser lines are projected sequentially at four reference directions—0°, 90°, 180°, and 270°—using a laser pointer. These radial laser lines serve as a visual reference for the physical control line direction and are precisely projected using the laser pointer. The projection process begins by installing the laser pointer at the measurement station, adjusting its azimuth reading to 0°, and aligning it with the true north reference azimuth. Then, a horizontal laser beam is emitted, forming a radial laser line pointing true north on the working surface, extending outwards from the center point to the edge of the cylinder. Next, the azimuth is sequentially adjusted to 90°, 180°, and 270°, projecting three more radial laser lines pointing east, south, and west, respectively. The four laser lines are orthogonal to each other, forming a cross-shaped control line pattern. The laser lines are typically 1-3 mm wide, clearly visible on the masonry surface, providing intuitive directional guidance for the precise setting of endpoint markers.

[0053] In the extension direction of each radial laser line, radial endpoint markers are set according to the design radius of the current masonry layer. These radial endpoint markers are physical marks that define the design circumferential position and are set through precise distance measurement. The setting process first extracts the design radius of the current masonry layer from the design drawings. Then, on each radial laser line, the distance is measured from the center point along the direction of the laser line. First, determine the endpoint positions; then, use a steel ruler, laser rangefinder, or total station to accurately measure the distance; finally, set physical markers at the determined endpoint positions, such as metal measuring nails, crosshairs, or reflecting prisms. The markers should be stable and fixed and not easily moved; the endpoint markers in the four directions form four equal division points of the design circumference, which are key reference points for checking whether the masonry radius meets the design.

[0054] Polar coordinate measurements were performed on each radial endpoint marker to obtain the distance and azimuth values ​​of each endpoint marker relative to the center point of the masonry working face. Specifically, the measurement process used the center point of the working face as the measuring station (or converted to the center point through eccentric measurement) to observe each endpoint marker. The measurement mode was selected as polar coordinate mode, and the output parameters included distance values ​​(slope distance or horizontal distance) and azimuth values. The distance value reflects the actual distance between the endpoint marker and the center point, and ideally should be equal to the design radius. The azimuth value reflects the direction of the endpoint marker, and ideally should be 0°, 90°, 180°, or 270°. Multiple observations were performed on each endpoint marker, and the average value was taken as the final measurement result to reduce random errors. The measurement data provides a quantitative basis for subsequent azimuth verification.

[0055] Verify whether the deviation between the azimuth value and the design azimuth is within the allowable error range. Azimuth deviation verification is a quality control step to ensure the accuracy of the survey and control line direction, achieved by comparing the deviation value with the allowable value. The verification process calculates the deviation between the measured azimuth and the design azimuth at each endpoint marker; for the 0° direction, the design azimuth is 0°, and the deviation is the measured azimuth; for other directions, the deviations from 90°, 180°, and 270° are calculated respectively; then, the absolute value of the deviation in each direction is compared with the preset allowable error range, which is usually set to ±10 to ±30 (arcseconds), determined according to the accuracy requirements of the vertical kiln; when the absolute value of the deviation in a certain direction is not greater than the allowable error, that direction is considered qualified; when all four directions are qualified, the azimuth verification is passed.

[0056] When the azimuth deviation exceeds the allowable error range, the angle of the rotating gimbal is adjusted and the radial laser line is reprojected until the azimuth deviation meets the requirements. Specifically, the adjustment process first identifies the direction of the deviation exceeding the limit and calculates the angle that needs to be adjusted, which is the opposite of the measured deviation. Then, the rotating gimbal of the laser pointer is controlled to make fine adjustments according to the calculated angle, with an adjustment accuracy at the arcsecond level. The radial laser line is reprojected, and the endpoint marker is set in the new direction. Polar coordinate measurement and azimuth verification are performed again. If the direction still exceeds the limit, the adjustment continues. This iterative cycle continues until the azimuth deviation in all directions meets the requirements. This closed-loop adjustment mechanism ensures high accuracy of the azimuth of the measurement and control line and avoids the cumulative effect of directional deviation on the accuracy of roundness measurement.

[0057] The four radial endpoint markers, verified by azimuth, were physically secured. Specifically, the securing process employed appropriate methods based on the type of endpoint marker; for metal probes, they were firmly fixed to the masonry surface using expansion bolts or cement mortar; for reflecting prisms or targets, magnetic bases or dedicated brackets were used for fixation. After fixing, the endpoint markers were remeasured to verify that the fixing process did not cause any positional change; for markers that had changed position, they were readjusted to the accurate position and then fixed again. Physical fixation ensures the stability of the endpoint markers' positions during measurement and construction, providing a reliable physical foundation for the long-term use of the control line.

[0058] Metal control lines are laid along the laser line path on the working surface. Both ends of the control lines are fixed to the center point mark and radial endpoint mark on the working surface, forming a four-directional basic control line group. Specifically, stainless steel wire or piano wire with a diameter of 0.3-0.5mm is used as the control line material, possessing high tensile strength and a low coefficient of thermal expansion. A fixing device, such as a ground anchor or hook, is set at the center point mark to secure one end of the control line. The control line is extended towards the endpoint mark in the direction indicated by the laser line, ensuring that the control line coincides with the laser line. The other end of the control line is fixed at the endpoint mark, and an appropriate preload is applied to taut the control line into a physical straight line. Control lines are laid in all four directions, ultimately forming a cross-shaped control line group with the center point as the intersection. The laying of control lines transforms the virtual laser direction into a tangible and measurable physical reference, providing bricklayers with intuitive masonry guidance lines and surveyors with a stable dimensional measurement reference. This is a key technical measure for achieving precise masonry control.

[0059] In embodiments of the present invention, the detailed implementation steps for blind spot identification and determination include:

[0060] The four-directional radial deviation vectors are grouped into two groups: 0°-180° and 90°-270°. Specifically, the radial deviation vectors in the 0° direction (due north) and the 180° direction (due south) are grouped together as the 0°-180° group; the radial deviation vectors in the 90° direction (due east) and the 270° direction (due west) are grouped together as the 90°-270° group. Each group contains two deviation vectors in opposite directions, forming a pairing relationship. The physical significance of this grouping is that the symmetry of the opposing deviation vectors reflects the symmetrical characteristics of the cylinder deformation, while the asymmetry reflects the asymmetric deformation modes, which forms the basis for subsequent decomposition of symmetrical and asymmetric components.

[0061] Calculate the radial symmetry components corresponding to opposite directions within each group. Specifically, for the 0°-180° group, extract the 0° direction deviation. and 180° directional deviation ; Calculate the symmetric components When the deviations in two directions have the same sign, the symmetry component indicates that the overall size of the diameter is larger or smaller in that direction; when the deviations in two directions have different signs, the symmetry component is close to zero, indicating that there is no significant symmetry deviation in that direction. Similarly, the symmetry components are calculated for the 90°-270° group. The two symmetric components represent the symmetric deformation characteristics along the 0°-180° axial direction and the 90°-270° axial direction, respectively.

[0062] Amplitude consistency verification is performed on the radially symmetrical components to obtain the absolute value of the difference between the amplitudes of the symmetrical components in the 0°-180° group and the amplitudes of the symmetrical components in the 90°-270° group. Specifically, the verification process calculates the absolute value of the difference between the two groups of symmetrical components (i.e., The difference reflects the degree of difference in dimensional deviations between two orthogonal directions; a small difference indicates that the dimensional deviations in the two directions are similar, and the cylinder is enlarged or reduced in an approximately proportional manner, or is regularly eccentric; a large difference indicates that the dimensional deviations in the two directions are significantly different, and there may be elliptic deformation or other asymmetric deformation.

[0063] When the absolute value is less than a preset symmetry threshold, the vector synthesis result of the radial symmetry components in the four directions is used as the eccentric displacement vector. Specifically, during the synthesis process, when the absolute value of the difference is less than the preset symmetry threshold, it is determined that the cylinder mainly exhibits overall eccentricity without significant ellipticization or higher-order deformation; at this time, the radial deviation in the four directions is mainly caused by the offset of the center. The average deviation in the 0° direction and the 90° direction is calculated as the northward eccentric component. and the eccentric component to the east The two components are vector-synthesized to obtain the magnitude and direction angle of the eccentric displacement vector. The eccentric displacement vector accurately describes the offset direction and amount of the circle's center, providing a direct basis for the generation of subsequent correction commands.

[0064] The radial asymmetric components corresponding to opposite directions within each group are calculated, and their phase distribution is analyzed to extract the zeroth, first, second, and third harmonic components. Specifically, the analysis process first calculates the asymmetric components in each direction. For the deviation of opposite pairing, the radial asymmetric components... In the formula, Indicates angle The radial deviation; then the radial asymmetric components in four directions (or eight directions) are used as discrete angle functions. Perform a discrete Fourier transform or direct harmonic fitting on the function to decompose it into harmonic components of different orders: ;in, It is the zeroth harmonic (mean component). The amplitude of the first harmonic. The amplitude of the second harmonic. The amplitude of the third harmonic. The phase angle is given. Each harmonic component corresponds to a different deformation mode: the zeroth harmonic reflects the overall deviation reference; the first harmonic reflects the overall eccentricity; the second harmonic reflects elliptic deformation; and the third harmonic reflects triangular deformation. Harmonic decomposition breaks down complex spatial deformation into simple mode superposition, providing a frequency domain perspective for deformation feature identification.

[0065] When the amplitude of the second harmonic component exceeds a preset second harmonic threshold in proportion to the total energy of the asymmetric components, the cylinder is determined to have elliptic deformation. Specifically, the determination process first calculates the total energy of the asymmetric components, defined as the sum of the squares of the amplitudes of each harmonic; then, it calculates the proportion of the second harmonic energy in the total energy; this proportion is compared with a preset second harmonic threshold; when the proportion exceeds the preset threshold, it indicates that the second harmonic is the dominant mode of deformation, and the cylinder is determined to have significant elliptic deformation. The characteristic of elliptic deformation is that the cylinder cross-section is elliptical, with a major axis and a minor axis. The radius along the major axis is larger, and the radius along the minor axis is smaller, with a difference of 90° between them. The identification of elliptic deformation provides a basis for deformation type prediction in blind zone analysis.

[0066] When the amplitude of the first or third harmonic component accounts for a proportion of the total energy of the asymmetric components exceeding a preset odd-harmonic threshold, the cylinder is determined to have odd-harmonic deformation. Specifically, the determination process calculates the proportion of the first and third harmonic energy in the total energy; compares this proportion with the preset odd-harmonic threshold; when the first harmonic energy exceeds the corresponding preset proportion threshold, it indicates that the first harmonic dominates, corresponding to overall eccentric deformation; when the third harmonic energy exceeds the corresponding preset threshold, it indicates that the third harmonic dominates, corresponding to triangular deformation, with the cylinder cross-section approximately triangular and extreme values ​​appearing in three directions at 120° intervals. The spatial distribution characteristics of odd-harmonic deformation are significantly different from those of even harmonics, and the prediction methods for extreme value locations are also different, requiring specialized identification and processing.

[0067] When elliptic deformation or odd harmonic deformation is identified, the blind zone coverage angle of the four-directional control line group is calculated. Specifically, for the four-directional control line group, the azimuth angles of the control lines are 0°, 90°, 180°, and 270°, and the angular interval between adjacent control lines is 90°. Each interval region (e.g., 0°-90°, 90°-180°, etc.) is a potential blind zone coverage angle because there is no direct radial measurement data in this region. The four blind zone coverage angles are (0°, 90°), (90°, 180°), (180°, 270°), and (270°, 360°), with an angular width of 90° for each region. The existence of blind zone coverage angles means that if the deformation extreme value location happens to be located in these regions, the four-directional measurements will not be able to directly capture the extreme value, leading to a deviation in the deformation assessment.

[0068] Based on the major axis azimuth angle of the elliptic deformation or the dominant mode frequency of the odd harmonic deformation, the expected extreme value location within the corresponding blind zone coverage angle is calculated and determined. Specifically, the calculation process for elliptic deformation involves the phase angle of the second harmonic. Indicates the azimuth angle of the major axis, and the extreme position of the major axis is: and The extreme position of the minor axis is and Determine whether these extreme value locations fall within the blind zone coverage angle of the four-directional control lines. For third harmonic deformation, the three extreme value locations are distributed at 120° intervals, with the initial azimuth angle being... Determined, the extreme value location is , and ;in, and These represent the azimuth angles of the major axis extrema and the minor axis extrema, respectively. , and These represent the azimuth angles of the first, second, and third harmonic extrema, respectively; similarly, it is used to determine whether the area falls within the blind zone. The accurate calculation of the expected extremum location provides a theoretical basis for quantitatively assessing blind zone risk.

[0069] When the angular deviation between the expected extreme value position and the measured four-directional control line is greater than the preset extreme value deviation angle, it is determined that there is a detection blind zone in the four-directional basic control line group. Specifically, the determination process calculates the angular deviation between each expected extreme value position and the azimuth angle of the nearest control line. ,in, Indicates the expected extreme azimuth angle. The azimuth angle of the i1th control line is represented by ; i1 traverses the azimuth angles of the four control lines; the deviation is compared with the preset extreme value deviation angle; when the deviation is greater than the threshold, it indicates that the extreme value position is far from all control lines, and the four-direction measurement cannot fully represent the extreme value characteristics, thus indicating the existence of a detection blind zone; when the deviation of all extreme value positions is not greater than the threshold, it indicates that the four-direction measurement basically covers the main deformation characteristics, and the risk of blind zone is low. This quantitative judgment method avoids subjective judgment and ensures the accuracy and consistency of blind zone identification.

[0070] In an embodiment of the present invention, the detailed implementation steps for establishing a supplementary monitoring and control line include:

[0071] The set of sensitive azimuth angles for the blind zone is calculated based on the major axis azimuth angle or the dominant mode frequency. Specifically, for elliptic deformation, the calculation process determines four sensitive azimuth angles based on the major axis azimuth angle of the second harmonic, including the two ends of the major axis (positions of maximum deviation) and the two ends of the minor axis (positions of minimum deviation), with the azimuth angles being respectively... , , , For third harmonic distortion, three sensitive azimuth angles are determined based on the phase angle of the dominant mode, distributed at 120° intervals. All sensitive azimuth angles are then aggregated to form a set of blind zone sensitive azimuth angles, which identifies the critical directions requiring precise measurement via supplementary control lines.

[0072] The system determines whether the angular deviation between the set of sensitive azimuth angles in the blind zone and any of the eight standard directions (45°, 135°, 225°, and 315°) is less than a preset azimuth matching threshold. Specifically, the determination process iterates through each sensitive azimuth angle in the set, calculating its angular deviation from the four standard supplementary directions (45°, 135°, 225°, and 315°). For each sensitive azimuth angle, the closest standard direction is extracted, and the absolute value of the deviation is calculated. This deviation is then compared to the preset azimuth matching threshold (usually set to 15°-20°). When the deviation of a sensitive azimuth angle is less than the threshold, it is determined that the sensitive direction can be represented by the corresponding standard direction, and the two approximately coincide. After iterating through all sensitive azimuth angles, the matching results are statistically analyzed.

[0073] When all blind zone sensitive azimuth angles have corresponding standard eight directions and the deviation angle is less than the azimuth matching threshold, the standard eight-direction measurement and control mode is triggered to establish supplementary measurement and control lines. Specifically, during the establishment process, when the matching conditions are met, the system automatically triggers the standard eight-direction mode; on the working surface, the same procedure as establishing the four-direction basic measurement and control lines is adopted, and radial laser lines are projected sequentially in the four directions of 45°, 135°, 225°, and 315°; endpoint markers are set according to the design radius; polar coordinate measurement and azimuth angle verification are performed; after verification, physical fixing is performed; and metal measurement and control lines are laid. Finally, eight evenly distributed radial measurement and control lines are formed, with an angle interval of 45°, doubling the spatial sampling density, which can effectively cover the extreme positions of second harmonic deformations such as ellipticization. The standard eight-direction mode is easy to operate, with preset parameters, and is suitable for most common deformation situations.

[0074] When the deviation angle of at least one blind zone sensitive azimuth from all eight standard directions exceeds the azimuth matching threshold, the azimuth of the supplementary control line is dynamically determined based on the set of blind zone sensitive azimuths. Specifically, the determination process identifies all sensitive azimuths that deviate excessively from the standard directions, as these azimuths cannot be effectively represented by the eight standard directions. These sensitive azimuths are directly used as the azimuths of the supplementary control line without standardization correction, ensuring that the control line is accurately aligned with the extreme deformation location. For sensitive azimuths that can be represented by the standard directions, the simplified operation of the standard directions is still used. The final determined set of supplementary control line azimuths may include both standard and non-standard directions, forming a mixed layout. This dynamic determination mechanism maximizes the targeting of the measuring point layout, ensuring that key deformation features are accurately captured.

[0075] The azimuth direction of each supplementary control line is sequentially located using a laser theodolite, and radial endpoint marks are added. Specifically, the positioning process involves setting up a laser theodolite at the center point of the working surface and inputting the azimuth parameters of the supplementary control lines; the instrument automatically or manually rotates to the specified azimuth angle and emits a horizontal laser beam to form a radial laser line; endpoint marks are set at the designed radius positions of the laser lines, using the same marking format as the basic control lines; the above operation is repeated for each supplementary direction to complete the endpoint marking of all supplementary control lines. The positioning process ensures the azimuth accuracy of the supplementary control lines, providing an accurate directional reference for subsequent measurements.

[0076] Polar coordinate measurements were performed on the supplementary radial endpoint markers to obtain the measured radius and azimuth of the supplementary direction. Specifically, the measurement process used the center point of the working face as the station to observe each supplementary endpoint marker; distance and azimuth values ​​were read, with the distance value being the measured radius of the supplementary direction; the azimuth value was used to verify the directional accuracy of the supplementary control line; multiple observations were performed on each supplementary endpoint to improve measurement accuracy. The measured radius value of the supplementary direction provides deformation information for areas not covered by the original four directions, filling in measurement blind spots.

[0077] The original four-direction measured radius values ​​are merged to form a complete eight-direction radial measurement dataset. Specifically, the merging process arranges the original four-direction measured radius values ​​(0°, 90°, 180°, 270°) and the measured radius values ​​of the supplementary directions in ascending order of azimuth. For the standard eight-direction model, the supplementary directions are 45°, 135°, 225°, and 315°, resulting in eight evenly distributed data points after merging. For the dynamic azimuth model, the supplementary directions may be non-standard angles, resulting in a non-uniform dataset that covers key locations. Each element in the dataset contains information such as azimuth, measured radius value, and deviation value, forming a structured measurement data table.

[0078] Data integrity verification was performed on a complete radial measurement dataset in eight directions. Specifically, the verification process checked for missing or outlier values ​​in the dataset. Missing value checks verified whether each expected direction had a corresponding measurement record; if missing values ​​were found, a remeasurement process was triggered. Outlier checks identified data deviating from the normal range through statistical analysis, using the 3σ criterion or box plot method to mark data exceeding the normal range as suspicious values ​​requiring review or remeasurement. Simultaneously, the consistency of azimuth angles was checked to verify whether the deviation between the measured and designed azimuth angles was within the allowable range. Data timestamps were also checked to ensure all data were collected within the same time window, avoiding the influence of deformation caused by excessively long time spans. After the integrity verification passed, the dataset was confirmed to be usable for subsequent roundness fitting and error assessment, ensuring the reliability of the analysis results.

[0079] In embodiments of the present invention, the detailed implementation steps for performing roundness contour fitting calculations include:

[0080] The radial coordinates of the complete eight-direction radial measurement dataset are converted into a two-dimensional coordinate point set in the Cartesian coordinate system. Specifically, the conversion process extracts the azimuth angle for each measurement point in the dataset. and measured radius value Establish a Cartesian coordinate system with the correction center point as the origin, with the X-axis pointing east and the Y-axis pointing north; apply the conversion formula from polar coordinates to Cartesian coordinates: , The coordinates of each measurement point in the Cartesian coordinate system were calculated. The coordinates of all measurement points are aggregated to form a two-dimensional coordinate point set. This coordinate point set describes the discrete contour of the cylinder's cross-section in the form of a planar point cloud, providing data input for circular fitting.

[0081] The process involves creating a discrete profile point cloud of the cylinder's cross-section. This discrete profile point cloud is a digital representation of the cylinder's actual geometry, containing positional and attribute information. The formation process organizes the converted two-dimensional coordinate point set into a point cloud data structure. Each point contains attributes such as X-coordinate, Y-coordinate, azimuth, and radius. The spatial distribution of the point cloud reflects the actual shape of the cylinder's cross-section, and the radial positional variations of the points reflect roundness deviations and deformation characteristics. The point cloud data can be displayed as a scatter plot using visualization tools, visually presenting the cylinder's deformation morphology; it can also be exported to a standard point cloud format for further processing in CAD software or professional analysis software. The discrete profile point cloud serves as a bridge connecting measurement data and geometric evaluation.

[0082] The minimum region circle evaluation method is used to fit the discrete contour point cloud. Specifically, the fitting process uses an optimization algorithm (such as genetic algorithm, particle swarm optimization, or gradient descent) to search for the optimal circle center coordinates. and inner and outer circle radii , The optimization objective is to minimize the width of the annulus; the constraint is that all contour points lie between the inner and outer circles, i.e. The algorithm applies to all points; it iterates through the search, continuously adjusting the center position and radius to gradually reduce the width of the annulus; it stops when the convergence condition is met (such as the upper limit of the number of iterations or the change in the annulus width being less than a threshold), and outputs the optimal solution. The minimum region circle method is more rigorous than the least squares circle method, yields more conservative evaluation results, and better meets the requirements of geometric tolerance standards, making it the preferred method in precision measurement.

[0083] The fitted circle center and roundness error values ​​are obtained. Specifically, the fitted circle center coordinates... This represents the position of the geometric center of the best-fit circle in the working surface coordinate system. This position minimizes the difference between the maximum and minimum distances from all contour points to the center, representing the geometric center of the actual cylinder cross-section. The roundness error value is defined as the width of the annulus of the minimum region circle. The roundness error value quantifies the maximum deviation of the contour point from the ideal circle and is a key indicator for judging the quality of masonry. The smaller the roundness error value, the closer the cross-section of the cylinder is to the ideal circle, and the higher the quality of masonry.

[0084] The coordinate difference between the fitted circle center and the corrected center point is calculated to obtain the direction component of the circle center offset vector. The circle center offset vector is a vector parameter describing the deviation of the actual circle center from the theoretical circle center. The calculation process extracts the fitted circle center coordinates. and correct center point coordinates ; Calculate the eastward offset component and northward offset components The two directional components form the rectangular coordinate representation of the center offset vector. A positive eastward component indicates an eastward offset of the center, while a negative component indicates a westward offset; a positive northward component indicates a northward offset of the center, while a negative component indicates a southward offset. This decomposition of directional components provides a quantitative basis for subsequent correction operations.

[0085] The magnitude and direction angle of the center offset vector are calculated through vector composition operations. The magnitude and direction angle are polar coordinate representations of the offset vector, providing a more intuitive description of the magnitude and direction of the offset. The calculation process uses the Pythagorean theorem to calculate the vector's magnitude (length) based on the Cartesian coordinate components; the vector's magnitude represents the distance of the center offset and is the direct basis for the correction value. Then, the direction angle is calculated. The direction angle, with true north as 0° and clockwise as positive, ranges from 0° to 360°, indicating the orientation of the deviation. The direction angle indicates the direction in which correction should be applied and serves as the direct basis for the correction direction. The polar coordinate representation of the vector transforms the complex two-dimensional deviation into easily understood and operable distance-direction parameter pairs, providing clear correction guidance for on-site construction personnel.

[0086] The decision to require masonry correction of the kiln structure is based on the magnitude of the center offset vector. Specifically, the determination process compares the magnitude of the center offset vector with a preset correction trigger threshold, which is determined according to the vertical kiln design requirements and construction specifications. When the magnitude of the center offset vector is greater than the offset threshold, it is determined that the center offset exceeds the allowable range, the kiln axis deviates from the design position, and masonry correction is required to avoid cumulative errors leading to excessive verticality of the kiln. When the magnitude is not greater than the offset threshold, it is determined that the center offset is within an acceptable range, no correction is needed, and normal masonry construction can continue. This threshold determination mechanism avoids unnecessary correction operations while ensuring that critical deviations are corrected in a timely manner.

[0087] When the magnitude of the center offset vector exceeds the preset correction initiation threshold, a masonry correction command is generated. The masonry correction command is a structured command guiding the correction operation, containing complete correction parameters and strategies. The generation process extracts the magnitude of the center offset vector as the total correction value and the direction angle as the correction direction. The correction strategy is determined based on the magnitude of the offset. When the total correction value is small (less than the preset correction threshold, such as 15mm), a single-layer correction strategy is adopted, correcting all offsets at once in the next masonry layer. In this case, the single-layer correction value is recorded as the total correction value. When the total correction value is large, a layered progressive correction strategy is adopted, gradually correcting the offset in subsequent layers to avoid excessively sharp masonry turns due to excessively large single-layer correction values. The single-layer correction value is defined as the ratio of the total correction value to the number of correction layers. Simultaneously, the correction direction is marked, indicating which direction the formwork or block position should be adjusted during the masonry process. Correction instructions are output in the form of text descriptions, graphic annotations, or digital instructions to ensure that construction personnel can accurately understand and execute them; the instructions also include correction verification requirements, requiring retesting to verify the correction effect after the correction layer is completed.

[0088] In embodiments of the present invention, the detailed implementation steps for establishing a vertical sequence of layered circle center coordinates include:

[0089] During the construction of the tower-type vertical kiln, after each layer of masonry is completed, radial measurements in four or eight directions and calculations of the center coordinates are performed on the corresponding layer. Specifically, the operation process involves executing a complete measurement procedure when each masonry layer meets the measurement conditions (usually after completion and initial curing); establishing or updating the control line group for that layer, using a four- or eight-direction layout, selected according to the complexity of deformation; performing polar coordinate measurements on the endpoints of each control line to obtain the measured radius values; transforming the measurement data into a coordinate system to form a contour point cloud; and using the minimum area circle method to fit the roundness and calculate the fitted center coordinates of the layer. The measurements and calculations for each layer are performed independently and do not affect each other, ensuring the temporal resolution and spatial independence of the data.

[0090] The planar coordinate components of the center coordinates of the corresponding masonry layer are correlated with the vertical elevation coordinates of that layer. Specifically, the correlation process extracts the planar coordinate components of the fitted center, including east and north coordinates; the vertical elevation coordinates of the top surface of the masonry layer are obtained through leveling or total station three-dimensional coordinate measurement, with the overall engineering elevation system being used as the elevation datum; the planar coordinates and elevation coordinates are combined to form three-dimensional coordinates, which fully describe the position of the center of the layer in three-dimensional space. The establishment of the three-dimensional coordinates provides a data foundation for subsequent axis spatial analysis and verticality assessment.

[0091] A single-layer data record containing three-dimensional information and center coordinates is generated. This single-layer data record is a structured data unit storing the measurement results of a single masonry layer. In addition to the three-dimensional coordinates, the record includes auxiliary information such as layer number, measurement date and time, roundness error value, center offset vector, number of measurement directions (4 or 8), and the surveyor. The data is stored in the form of database records, spreadsheet rows, or XML structures for easy querying and analysis. The single-layer data record is an important component of the masonry quality archive, ensuring the traceability and auditability of the measurement data.

[0092] The coordinate data records of the center of each masonry layer are sorted from low to high according to their vertical elevation coordinates. Specifically, the sorting process collects the data records of all completed masonry layers, extracts the elevation coordinates of each record as the sorting key, and arranges them in ascending order of elevation, with the lowest layer (bottom) at the beginning and the highest layer (current layer) at the end. The sorted dataset forms a sequence of increasing vertical elevation, reflecting the temporal order and spatial superposition of the masonry construction. The sorting operation ensures that the logical order of the sequence is consistent with the vertical order of the physical structure, providing the correct data arrangement for axis fitting and trend analysis.

[0093] A layered vertical sequence of center coordinates is constructed. Specifically, the construction process organizes all sorted single-layer data records into a list or array structure to form a sequence. The length of the sequence dynamically increases with the progress of masonry construction, adding one element with each completed layer. The sequence data can be visualized by plotting the center points of each layer in a three-dimensional coordinate system and connecting them to form a spatial curve, intuitively presenting the spatial shape and offset trend of the cylinder axis. The layered vertical sequence of center coordinates is the core data foundation for cumulative error monitoring and systematic offset identification, providing complete information support for high-level quality analysis.

[0094] In an embodiment of the present invention, the detailed implementation steps of the operation procedure for determining whether to trigger the re-measurement of the permanent baseline center point at the bottom include:

[0095] A three-dimensional spatial straight line is fitted to the vertical sequence of layered circle center coordinates to obtain the best-fitting line. Specifically, the fitting process uses the three-dimensional coordinates of each layer's circle center in the vertical sequence as a data point set to establish the parametric equations of the spatial straight line. The spatial straight line is represented by a linear function of two planar coordinate components with respect to elevation coordinates. The eastward coordinate is equal to the reference eastward coordinate plus the product of the eastward direction coefficient and elevation; the northward coordinate is equal to the reference northward coordinate plus the product of the northward direction coefficient and elevation. The reference coordinates represent the planar position of the line at the reference elevation, and the direction coefficient represents the spatial inclination of the line. These parameters are solved using the least squares method to minimize the sum of squared distances from all data points to the fitted line. The solution process involves establishing a system of normal equations with partial derivatives equal to zero and solving them through matrix operations to obtain the optimal parameter values. The best-fitting line represents the average trend and overall orientation of the cylinder axis, serving as the baseline for evaluating the straightness of the axis and a reference standard for determining whether a systematic offset of the axis has occurred.

[0096] Calculate the vertical distance from the center coordinates of each layer to the best-fit line. Specifically, for each center coordinate point, firstly, based on the elevation coordinates of that point, use the equation of the line to calculate the coordinates of the projection point on the line at that elevation. The eastward and northward components of the projection point coordinates are calculated using the parametric equation of the line. Then, calculate the planar distance between the actual center point and the projection point; this distance is the vertical distance from the center of that layer to the fitted line. The vertical distance is calculated using the distance formula between two points, by adding the squares of the differences in the eastward and northward coordinates and taking the square root. The value of the vertical distance reflects the degree of deviation of the center of that layer from the overall axis trend. A large distance indicates a significant deviation for that layer, possibly due to construction errors or local deformation; a small distance indicates that the layer is close to the ideal axis position, indicating good masonry quality. The vertical distances of all layers form a deviation distribution sequence, which describes the curvature and deviation distribution pattern of the axis throughout the entire height range.

[0097] Identify the maximum and minimum vertical distances among all vertical distances. Specifically, the identification process iterates through all vertical distances, finding the maximum and minimum values; recording the corresponding layer number and elevation position; the maximum vertical distance represents the layer furthest from the axis, the extreme position of the axis curvature; the minimum vertical distance represents the layer closest to the ideal axis, the position of the smallest deviation. The spatial distribution characteristics of the extreme values ​​(such as whether they are concentrated in a certain elevation range) provide clues for identifying the causes of deviations.

[0098] The difference between the two is defined as the straightness deviation of the cylinder axis. Specifically, the straightness deviation is defined as the difference between the maximum and minimum vertical distances; this definition method is consistent with the definition of the straightness tolerance zone in the geometric tolerance standard, representing the diameter of the smallest cylinder required to encompass all center points; the smaller the straightness deviation, the closer the axis is to the ideal straight line, and the better the perpendicularity control; the larger the deviation, the more severe the axis bending, which may indicate systematic offset or construction quality problems. The unit of straightness deviation is millimeters, which is a key criterion for determining whether re-measurement is necessary.

[0099] When the straightness deviation exceeds the preset straightness threshold, statistical analysis is performed on the azimuth angles of the center offset vectors of each layer on the horizontal plane. Specifically, the analysis process triggers a depth analysis process when the straightness deviation exceeds the preset straightness threshold (usually set to 0.1%-0.3% of the cylinder height or an absolute value of 50-100mm); the azimuth angles of the center offset vectors of each layer (the offset relative to the bottom reference center point or the fitted axis reference point) on the horizontal plane are extracted; the azimuth angle is defined as the angle between the offset vector and the due north direction, ranging from 0° to 360°; the azimuth angles of each layer are combined into an angle sequence, which reflects the directional distribution characteristics of the offset of each layer.

[0100] Calculate the circumferential mean and standard deviation of the azimuth angles. Specifically, the calculation process cannot directly use the arithmetic mean of the angles (because 0° and 360° are equivalent, which would lead to errors), but instead uses a vector averaging method; convert each azimuth angle into a unit vector; calculate the vector sum of all unit vectors. The circumferential mean is defined as the direction angle of the vector sum, and needs to be adjusted to the range of 0°-360° according to the quadrant; the magnitude of the vector sum reflects the concentration of the azimuth angles; the circumferential standard deviation... In the formula, m represents the total number of azimuth angle samples; a small circumferential standard deviation indicates that the offset directions of each layer are concentrated and there is a dominant direction; a large standard deviation indicates that the offset directions are dispersed and the offset directions of each layer are highly random.

[0101] When the circumferential standard deviation is less than a preset directional concentration threshold, a dominant offset direction is identified, and this is considered a systematic trend offset. Systematic offset identification is crucial for distinguishing between random and systematic deviations. The determination process compares the calculated circumferential standard deviation with the preset directional concentration threshold. When the circumferential standard deviation is less than the threshold, it indicates that the offset directions of each layer are highly consistent and concentrated near the circumferential mean, thus identifying a dominant offset direction. The circumferential mean is the azimuth angle of the dominant direction, indicating the direction of the systematic offset. Systematic trend offsets are characterized by low randomness, strong directionality, and long duration. They are typically caused by baseline offsets, equipment system errors, or construction system deviations, and are significantly different from random construction errors, requiring tracing the root cause and implementing systematic correction.

[0102] When a systematic trend of offset is identified and the cumulative offset is determined to increase continuously with elevation, the procedure for re-measurement of the bottom permanent benchmark center point is triggered. Specifically, the judgment process, based on confirming the systematic trend of offset, further analyzes the elevation correlation of the cumulative offset; calculates the projection components of the offset vector of each layer's center in the dominant direction to form a cumulative offset sequence; performs correlation analysis or linear fitting on the cumulative offset and elevation, and calculates the slope and correlation coefficient; when the slope is positive and the correlation coefficient is significant (e.g., greater than 0.7), it indicates that the offset continues to increase with elevation, showing a cumulative trend. This situation indicates that the bottom benchmark may have shifted, or the laser plumb line may have a systematic tilt, causing the measurement error to accumulate linearly with height. When the three conditions of exceeding the straightness deviation limit, direction concentration, and significant cumulative trend are simultaneously met, the procedure for re-measurement of the bottom permanent benchmark center point is triggered. By recalibrating the benchmark and equipment, the systematic error source is eliminated, and the accuracy of the measurement system is restored.

[0103] In embodiments of the present invention, the detailed steps of performing the retest operation include:

[0104] In the re-measurement process, the three-dimensional coordinates of the bottom permanent benchmark center point are first verified by measurement. Specifically, the verification process uses a high-precision total station or GNSS equipment to measure the three-dimensional coordinates of the bottom permanent benchmark center point based on the external control network. The measurement methods include resection, forward intersection, or network adjustment to ensure independence and reliability. The measurement accuracy is required to reach the millimeter level, and the accuracy is improved through multiple observations and rigorous adjustment. After the measurement is completed, the verification measurement coordinates of the benchmark point are obtained. These coordinates are independent measurements based on the current control network.

[0105] The verification measurement coordinates are obtained and compared with the original coordinates. Specifically, the comparison process extracts the original coordinates of the bottom permanent reference center point from the reference coordinate database. These coordinates are the reference values ​​determined and archived during the initial stage of construction. The difference between the two sets of coordinates and the magnitude of the three-dimensional displacement vector are calculated respectively. This magnitude quantifies the total displacement of the reference point and reflects the stability of the reference point.

[0106] When the coordinate difference is not greater than the preset reference stability threshold, the laser plumb line is recalibrated and re-calibrated. Specifically, during the operation, when the magnitude of the three-dimensional displacement vector is not greater than the preset reference stability threshold (usually set to 2-3 mm), the reference point position is considered stable and no significant displacement has occurred. At this time, the root cause of the systematic offset lies in the systematic error of the laser plumb line, such as optical axis tilt, rotation error, or zero-point drift. The laser plumb line is recalibrated, including optical axis perpendicularity check, compensator adjustment, and zero-point reset. Standard calibration equipment or a dedicated calibration site is used, and the calibration is performed according to the instrument calibration procedure. After calibration, accuracy verification is performed to ensure that the equipment performance is restored to the factory specifications. The calibrated laser plumb line is re-erected at the reference point, adjusted to strict centering and leveling, and the vertical laser projection channel is re-established. Measurements are then continued upward from the current masonry layer. The equipment calibration operation ensures the accuracy of the measurement system and eliminates the cumulative effect of systematic errors.

[0107] When the difference in coordinates between the permanent bottom reference center point and the baseline exceeds the preset reference stability threshold, the reference coordinate database is updated and a new vertical laser projection channel is established. Specifically, during the operation, when the magnitude of the three-dimensional displacement vector exceeds the reference stability threshold, it is determined that the reference point has undergone significant displacement, possibly caused by foundation settlement, foundation deformation, or external force damage; the original reference coordinates are no longer accurate, and continued use will lead to systematic errors; the verified measurement coordinates are used as the new reference coordinates, the reference coordinate database is updated, and the update time and reason are recorded; based on the new reference coordinates, the center coordinates of the completed masonry layers are uniformly corrected, and the offset of each layer relative to the new reference is recalculated; a new vertical laser projection channel is established at the new reference position, and a calibrated laser plumb line is used for strict centering; the current masonry layer is re-measured to obtain the corrected center point coordinates based on the new reference, which serves as the starting point for subsequent masonry work. The reference update operation ensures the consistency and continuity of the measurement system, avoids measurement distortion caused by reference displacement, and provides reliable reference support for subsequent masonry work.

[0108] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0109] All formulas in this manual are dimensionless and calculated numerically. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters and thresholds in the formulas are set by those skilled in the art according to the actual situation.

[0110] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A laser measurement and control system for tower-type vertical kiln masonry based on cross-shaped control lines, characterized in that, include: The parameter compensation acquisition module is used to obtain the three-dimensional spatial coordinates of the permanent reference center point at the bottom of the tower vertical kiln. The vertical laser projection channel established at the permanent reference center point projects the vertical center point to the current masonry working face, and calculates the refraction offset and scattering attenuation coefficient based on the air temperature field distribution and dust concentration distribution on the laser beam propagation path during the projection process. The control line group construction module performs dual correction on the projection landing point coordinates based on the refraction offset and scattering attenuation coefficient to obtain the corrected center point coordinates, and establishes a four-directional basic control line group on the masonry working surface with the corrected center point coordinates as the origin. The deviation dimension measurement module uses a high-precision total station to perform radial linear dimension measurement on the four-direction basic control line group, obtains the measured radius values ​​in the four directions, compares them with the design radius values, and obtains the radial deviation vector in the four directions. The blind zone intelligent identification module identifies and determines blind zones based on four-direction radial deviation vectors. If a detection blind zone is determined, a supplementary control line is established between adjacent basic control lines. The supplementary control line is then used to measure the radial linear dimensions to obtain a complete radial measurement dataset in eight directions. The roundness profile fitting module performs roundness profile fitting calculations based on the complete radial measurement dataset in eight directions to obtain the roundness error value and center offset vector of the cylinder cross section. It determines whether the cylinder meets the design roundness requirements based on the roundness error value and generates masonry correction instructions based on the center offset vector. The cumulative error monitoring module is used to monitor the radius verification data and center coordinates of each masonry layer in real time during the masonry correction process, establish a vertical sequence of layered center coordinates, and determine whether to trigger the operation process of re-introducing the permanent reference center point at the bottom based on the vertical sequence of layered center coordinates.

2. The laser measurement and control system for tower-type vertical kiln masonry based on cross-shaped control lines according to claim 1, characterized in that, The process of calculating the refraction offset and scattering attenuation coefficient includes: Multiple temperature monitoring sections are uniformly set at vertical intervals along the laser beam propagation path. Each temperature monitoring section contains multiple temperature measurement points radially distributed around the laser beam axis. By collecting data at the temperature measurement points and performing three-dimensional kriging space interpolation, the spatial temperature field distribution is obtained. Based on the atmospheric stratified refraction theory, the average temperature value at each temperature monitoring section is extracted by combining the spatial temperature field distribution, and the refractive index of the air at each temperature monitoring section is calculated. The laser propagation path between adjacent temperature monitoring sections is regarded as a small refraction segment. The cumulative refraction angle of the laser beam on the entire propagation path is calculated segment by segment using the piecewise integration method. The orthogonal projection length of the product of the cumulative refraction angle and the total propagation length of the laser beam on the working plane is taken as the refraction offset. Laser scattering dust concentration sensors were installed at the starting point, quarter point, midpoint, three-quarter point, and ending point of the laser beam propagation path to obtain measured dust concentration values ​​at five points. The continuous vertical distribution function of dust concentration was then fitted using spline interpolation. The local scattering attenuation coefficient of the laser beam in different path segments is calculated based on the continuous distribution function and the pre-stored dust particle size distribution parameters of the construction environment. The scattering attenuation coefficient is obtained by exponentially accumulating the local scattering attenuation coefficients of each path segment.

3. The laser measurement and control system for tower-type vertical kiln masonry based on cross-shaped control lines according to claim 1, characterized in that, The process of performing double correction includes: The degree of energy distribution distortion of the laser spot is evaluated based on the scattering attenuation coefficient. When the degree of energy distribution distortion is greater than a preset distortion threshold, a high-resolution image of the laser spot is acquired, and the centroid coordinates of the spot are identified. The identified centroid coordinates of the spot are used as preliminary correction coordinates. When the degree of energy distribution distortion is not greater than the preset distortion threshold, the geometric center coordinates of the laser spot are used as preliminary correction coordinates. Position compensation is applied to the preliminary corrected coordinates in the opposite direction of the refraction offset to obtain the corrected center point coordinates; and the standard deviation of the corrected center point coordinates is calculated by repeatedly measuring within a preset time interval. When the standard deviation is less than a preset stability threshold, the correction is confirmed to be effective and the average value of the multiple measured coordinates is taken as the final corrected center point coordinates.

4. The laser measurement and control system for tower-type vertical kiln masonry based on cross-shaped control lines according to claim 1, characterized in that, The process of establishing a four-directional basic control line group includes: With the final correction center point as the center, establish a coordinate system on the current masonry working surface, and with the center point of the masonry working surface as the measuring station, combine the azimuth reference north reference azimuth of the overall kiln design coordinate system; Based on the stated north reference azimuth, radial laser lines are projected sequentially in four reference directions—0°, 90°, 180°, and 270°—within the masonry working surface using a laser pointer. In the extension direction of each radial laser line, radial endpoint markers are set according to the design radius of the current masonry layer; polar coordinate measurements are performed on each radial endpoint marker to obtain the distance and azimuth angle values ​​of each endpoint marker relative to the center point of the masonry working surface, and the deviation of the azimuth angle value from the design azimuth angle is verified to be within the allowable error range; When the azimuth deviation exceeds the allowable error range, adjust the angle of the rotating gimbal and reproject the radial laser line until the azimuth deviation meets the requirements. The four radial endpoint markers verified by the azimuth angle are physically fixed, and metal control lines are laid on the working surface along the laser line path. The two ends of the metal control lines are fixed on the center point marker and the radial endpoint marker of the working surface, respectively, forming a four-direction basic control line group.

5. The laser measurement and control system for tower-type vertical kiln masonry based on cross-shaped control lines according to claim 1, characterized in that, The process of blind spot identification and determination includes: The four-direction radial deviation vectors are grouped into 0°-180° and 90°-270° groups, and the corresponding radial symmetry components in each group are calculated. The amplitude consistency of the radial symmetry components is checked, and the absolute value of the difference between the amplitude of the symmetry component in the 0°-180° group and the amplitude of the symmetry component in the 90°-270° group is obtained. When the absolute value is less than the preset symmetry threshold, the vector synthesis result of the four-direction radial symmetry components is used as the eccentric displacement vector. Calculate the radial asymmetric components corresponding to opposite directions within each group, perform phase distribution analysis on them, and extract the zeroth harmonic component, first harmonic component, second harmonic component, and third harmonic component; When the amplitude of the second harmonic component accounts for more than the total energy of the asymmetric components, the cylinder is determined to have elliptic deformation. When the amplitude of the first or third harmonic component accounts for a proportion of the total energy of the asymmetric components exceeding a preset odd harmonic threshold, it is determined that the cylinder exhibits odd harmonic deformation. When elliptic deformation or odd harmonic deformation is detected, the blind zone coverage angle of the four-directional control line group is calculated; and based on the major axis azimuth of the elliptic deformation or the dominant mode frequency of the odd harmonic deformation, the expected extreme value position within the corresponding blind zone coverage angle is calculated and determined. When the angular deviation between the expected extreme value position and the measured four-directional control line is greater than the preset extreme value deviation angle, it is determined that there is a detection blind zone in the four-directional basic control line group.

6. The laser measurement and control system for tower-type vertical kiln masonry based on cross-shaped control lines according to claim 1, characterized in that, The process of establishing supplementary control lines includes: Based on the major axis azimuth angle or dominant mode frequency, calculate the set of blind zone sensitive azimuth angles, and determine whether the angle deviation of the set of blind zone sensitive azimuth angles from any of the standard eight directions of 45°, 135°, 225°, and 315° is less than a preset azimuth matching threshold. When all blind zone sensitive azimuth angles have corresponding standard eight directions and the deviation angle is less than the azimuth matching threshold, trigger the standard eight-direction measurement and control mode and establish a supplementary measurement and control line. When the deviation angle between at least one blind zone sensitive azimuth angle and all standard eight directions is greater than the azimuth matching threshold, the azimuth angle of the supplementary control line is dynamically determined based on the set of blind zone sensitive azimuth angles. The azimuth direction of each supplementary control line is located sequentially using a laser theodolite, and radial endpoint marks are added. Polar coordinate measurements are performed on the supplementary radial endpoint marks to obtain the measured radius and azimuth of the supplementary direction. These values ​​are then merged with the measured radius values ​​of the original four directions to form a complete radial measurement dataset in eight directions. The data integrity of the complete radial measurement dataset in eight directions is then verified.

7. The laser measurement and control system for tower-type vertical kiln masonry based on cross-shaped control lines according to claim 1, characterized in that, The process of performing roundness profile fitting calculations includes: The radial coordinates of the complete eight-direction radial measurement dataset are converted into a two-dimensional coordinate point set in the Cartesian coordinate system to form a discrete contour point cloud of the cylinder cross-section. The minimum region circle evaluation method is used to fit the discrete contour point cloud to obtain the fitted circle center and roundness error value. Calculate the coordinate difference between the fitted circle center and the corrected center point coordinates to obtain the direction component of the circle center offset vector, and calculate the magnitude and direction angle of the circle center offset vector through vector composition operation; The cylinder is determined to be required to perform masonry correction based on the magnitude of the center offset vector. When the magnitude of the center offset vector is greater than the preset correction start threshold, a masonry correction instruction is generated. The masonry correction instruction includes the correction direction, correction value, and layered correction strategy.

8. The laser measurement and control system for tower-type vertical kiln masonry based on cross-shaped control lines according to claim 1, characterized in that, The process of establishing a vertical sequence of layered circle center coordinates includes: During the construction of the tower-type vertical kiln, after each layer of masonry is completed, radial measurements in four or eight directions and calculations of the center coordinates are performed on the corresponding layer. The planar coordinate components of the center coordinates of the corresponding layer are then correlated with the vertical elevation coordinates of that layer to form a single-layer center coordinate data record containing three-dimensional information. The coordinate data of the center of each masonry layer are sorted from low to high according to the vertical elevation coordinates to construct a vertical sequence of the center coordinates of each layer.

9. The laser measurement and control system for tower-type vertical kiln masonry based on cross-shaped control lines according to claim 1, characterized in that, The process of determining whether to trigger the re-induction of the permanent baseline center point at the bottom of the regression includes: Perform three-dimensional spatial line fitting on the vertical sequence of the layered circle center coordinates to obtain the best-fitting line; Calculate the vertical distance from the center coordinates of each layer to the best-fit line, identify the maximum and minimum vertical distances among all vertical distances, and define the difference between the two as the straightness deviation of the cylinder axis; When the straightness deviation exceeds the preset straightness threshold, the azimuth angle of the offset vector of each layer center on the horizontal plane is statistically analyzed to calculate the circumferential mean and circumferential standard deviation of the azimuth angle. When the circumferential standard deviation is less than the preset direction concentration threshold, it is determined that there is a dominant offset direction and it is identified as a systematic trend offset. When a systematic trend shift is identified and it is determined that the cumulative shift continues to increase with elevation, the operation procedure of re-examining the permanent baseline center point at the bottom is triggered.

10. The laser measurement and control system for tower-type vertical kiln masonry based on cross-shaped control lines according to claim 9, characterized in that, The process of performing a retest includes: In the re-measurement process, the three-dimensional coordinates of the bottom permanent reference center point are first measured to obtain the verification measurement coordinates. The verification measurement coordinates are compared with the original coordinates. When the coordinate difference is not greater than the preset reference stability threshold, the laser plumb line is recalibrated and re-calibrated. When the coordinate difference of the bottom permanent reference center point is greater than the preset reference stability threshold, the reference coordinate database is updated and the vertical laser projection channel is re-established.

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