A method for detecting the uniformity of a PVC film coating based on spectral analysis

Abstract

The application discloses a PVC film coating uniformity detection method based on spectral analysis, and relates to the technical field of spectral detection, which comprises the following steps: performing film surface position correlation on coating spectral information according to detection position information to generate coating position spectral data; performing film surface spectral difference identification on the coating position spectral data to generate base film intrinsic spectral data; performing spectral feature stripping on the coating position spectral data based on the base film intrinsic spectral data to generate coating coverage spectral data; performing spectral shape comparison on adjacent coating coverage positions in the coating coverage spectral data by using a spectral angle matching algorithm to output coating spectral fingerprint data; and identifying regional consistency states and local abnormal states of the PVC film coating from the coating spectral fingerprint data to output PVC film coating detection data. The application performs spectral feature stripping on the coating position spectral data based on the base film intrinsic spectral data, thereby improving the identification accuracy of PVC film coating spectral changes.

Description

Technical Field

[0001] This invention relates to the field of spectral detection technology, and in particular to a method for detecting the uniformity of PVC film coatings based on spectral analysis. Background Technology

[0002] In recent years, with the development of hyperspectral imaging, near-infrared spectroscopy, polymer film preparation, and surface coating quality inspection technologies, PVC film coating inspection has gradually shifted from manual visual inspection, sampling weighing, and local thickness measurement to continuous and spatial spectral characterization. During PVC film processing, the material composition, plasticizer distribution, film thickness, and light transmittance of the PVC base film, as well as the chemical composition, coverage thickness, and curing state of the surface coating, all affect the reflectance spectral response at different wavelengths. The peak positions, response amplitudes, and spectral shape changes at different detection locations can characterize the film surface material state. The correspondence between spectral response and film surface position distribution has become an important technical basis for evaluating the coverage state, thickness variation, and regional uniformity of PVC film coatings.

[0003] However, existing spectral detection methods for PVC film coatings typically rely on the overall spectral response of the coated film surface to determine the uniformity of the coating, lacking effective separation of the spectral components of the PVC base film and the coating. The thickness fluctuations, material ratio differences, and light transmittance variations of the PVC base film itself are easily superimposed on the coating spectral response, causing the base film changes and coating changes to become intertwined. This makes it difficult to accurately characterize local coating differences, affecting the accuracy of identifying the uniformity of the PVC film coating area and local abnormalities. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, this invention provides a PVC film coating uniformity detection method based on spectral analysis to solve the problem of inaccurate coating uniformity identification caused by the superposition of the spectral response of the PVC base film and the spectral response of the coating.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] This invention provides a method for detecting the uniformity of PVC film coatings based on spectral analysis. The method includes: acquiring coating spectral information and detection location information of the PVC film coating; performing film surface position correlation on the coating spectral information according to the detection location information to generate coating location spectral data; performing film surface spectral difference identification on the coating location spectral data to obtain the base film reference position and coating coverage position; extracting the base film spectral features from the base film reference position and matching the base film spectral features to the coating coverage position to generate base film intrinsic spectral data; and performing spectral feature stripping on the coating location spectral data based on the base film intrinsic spectral data to form coating difference spectral data. The coating coverage spectral data is mapped to the coverage response position based on the arrangement of the coating coverage position in the detection position information to generate coating coverage spectral data. The spectral angle matching algorithm is used to perform spectral shape comparison on adjacent coating coverage positions in the coating coverage spectral data to obtain the correlation of spectral changes. Based on the correlation of spectral changes, the coating coverage spectral data is segmented and organized into regional response segments to output coating spectral fingerprint data. The regional consistency state and local abnormal state of PVC film coating are identified from the coating spectral fingerprint data, and the regional consistency state and local abnormal state are collected into the detection position information to output PVC film coating detection data.

[0008] As a preferred embodiment of the PVC film coating uniformity detection method based on spectral analysis described in this invention, the specific steps for generating coating location spectral data are as follows:

[0009] Identify each detection point and its positional arrangement from the detection location information, and align the coating spectral information with each detection point to form film surface spectral calibration data;

[0010] Perform position misorder verification and misordered spectrum realignment correction on the membrane surface spectral calibration data, and output membrane surface position correction data;

[0011] The coating spectral information in the film position correction data is arranged into a position sequence according to the positional arrangement relationship to generate coating position spectral data.

[0012] As a preferred embodiment of the PVC film coating uniformity detection method based on spectral analysis described in this invention, the specific steps for obtaining the base film reference position and coating coverage position are as follows:

[0013] The PVC film band information and coating band information corresponding to each detection point in the coating position spectral data are segmented, classified and combined, and the dual-band response data of the film surface is output.

[0014] Synchronous difference comparison is performed on the PVC membrane band information and coating band information of adjacent detection points in the dual-band response data of the membrane surface to form spectral difference discrimination data;

[0015] Based on the spectral difference discrimination data, the spectral difference position of the detection point is calibrated, and the reference position of the base film and the coating coverage position are output.

[0016] As a preferred embodiment of the PVC film coating uniformity detection method based on spectral analysis described in this invention, the specific steps for generating the intrinsic spectral data of the base film are as follows:

[0017] The spectral response of the base film reference position is extracted from the spectral data of the coating position, and the PVC film band information in the spectral response is feature-collected to form the base film spectral feature data.

[0018] Based on the positional arrangement in the detection location information, the spectral characteristic data of the base film are paired with the coating coverage location item by item to generate the intrinsic spectral data of the base film.

[0019] As a preferred embodiment of the PVC film coating uniformity detection method based on spectral analysis described in this invention, the specific steps for forming coating difference spectral data are as follows:

[0020] Referring to the band order of the intrinsic spectrum data of the base film, the spectral response corresponding to the coating coverage position in the spectral data of the coating position is arranged side by side with the intrinsic spectrum data of the base film to form spectral stripping reference data;

[0021] The amplitude ratio of the spectral response in the same band in the spectral stripping reference data was statistically analyzed to determine the response ratio of the base film.

[0022] The spectral response of the intrinsic spectrum of the base film at each coating coverage location is adjusted according to the base film response ratio to form the base film corrected spectral data;

[0023] Remove the spectral response of the coating coverage location from the coating location spectral data in the base film correction spectral data, and output the coating difference spectral data.

[0024] As a preferred embodiment of the PVC film coating uniformity detection method based on spectral analysis described in this invention, the specific steps for generating coating coverage spectral data are as follows:

[0025] Based on the arrangement of coating coverage locations in the detection location information, coverage location is determined by the coating difference spectral data, and coverage response location data is output.

[0026] The coating difference spectral data are arranged according to the location order and adjacent relationships of the coverage response location data to generate coating coverage spectral data.

[0027] As a preferred embodiment of the PVC film coating uniformity detection method based on spectral analysis described in this invention, the specific steps for obtaining the correlation of spectral changes are as follows:

[0028] According to the arrangement of coating coverage locations, the spectral responses of adjacent coating coverage locations in the coating coverage spectral data are grouped into the same spectral group, and the adjacent coverage spectral data are output.

[0029] The spectral responses of each band in adjacent coverage spectral data are converted into spectral shape vectors, and the spectral angle between adjacent spectral shape vectors is calculated.

[0030] The degree of spectral continuity and spectral variation between adjacent coating coverage locations is determined based on the spectral angle, and then integrated into adjacent spectral variation data;

[0031] Based on the arrangement of adjacent coating coverage positions, the degree of spectral continuity and the degree of spectral change in adjacent spectral change data are sequentially concatenated to output the correlation relationship of spectral changes.

[0032] As a preferred embodiment of the PVC film coating uniformity detection method based on spectral analysis described in this invention, the specific steps for outputting the coating spectral fingerprint data are as follows:

[0033] Based on the correlation of spectral changes, the boundary of continuous variation in the spectral data of the coating coverage is confirmed, and regional response boundary data is obtained.

[0034] The coating coverage spectral data is segmented using regional response boundary data to form regional response segmented data. The correlation between each response segment and spectral change in the regional response segmented data is then combined segment by segment to output the coating spectral fingerprint data.

[0035] As a preferred embodiment of the PVC film coating uniformity detection method based on spectral analysis described in this invention, the specific steps for identifying the regional uniformity and local abnormality of the PVC film coating are as follows:

[0036] The continuity of the spectral shape of each response segment in the coating spectral fingerprint data and the degree of spectral shape change between adjacent response segments are analyzed to output segmented continuous state data.

[0037] Based on the segmented continuous state data, response segments that maintain a continuous degree of spectral continuity and spectral variation are identified as regionally consistent states, while response segments where the degree of spectral continuity is interrupted and response segments where the degree of spectral variation between adjacent response segments is discontinuous are identified as locally anomalous states.

[0038] As a preferred embodiment of the PVC film coating uniformity detection method based on spectral analysis described in this invention, the PVC film coating detection data is formed by recording the regional uniformity state and the local abnormal state into the detection point and position arrangement relationship in the detection location information, and summarizing the film surface state distribution.

[0039] The beneficial effects of this invention are as follows: By performing spectral feature stripping on the spectral data of the coating location using the intrinsic spectral data of the base film, the accuracy of identifying spectral changes in PVC film coatings is improved. After the influence of the base film spectrum is weakened, the spectral differences between different coating coverage locations caused by coating thickness, coverage continuity, and local defects can be more clearly preserved, reducing the interference of changes in PVC base film thickness, material composition, and light transmittance on the detection results; the coating difference spectral data can maintain the correspondence between coating changes and film surface position, enabling stable differentiation between continuous coating areas and local abnormal areas, and providing an accurate data basis for coating area division, spectral fingerprint formation, and uniformity identification, thereby improving the reliability and positioning accuracy of PVC film coating uniformity detection. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a flowchart of a method for detecting the uniformity of PVC film coatings based on spectral analysis.

[0042] Figure 2 This is a flowchart for outputting the differential spectral data of the coatings.

[0043] Figure 3 This is a flowchart for outputting the spectral fingerprint data of the coating.

[0044] Figure 4 This is a flowchart for outputting PVC film coating test data. Detailed Implementation

[0045] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0046] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0047] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0048] Reference Figures 1-4 As one embodiment of the present invention, this embodiment provides a method for detecting the uniformity of PVC film coating based on spectral analysis, comprising the following steps:

[0049] S1. Collect the coating spectral information and detection position information of the PVC film coating, perform film surface position correlation on the coating spectral information according to the detection position information, and generate coating position spectral data.

[0050] S1.1 Identify the detection points and their arrangement from the detection location information, and align the coating spectral information with each detection point to form film surface spectral calibration data.

[0051] Specifically, based on the membrane length position, membrane width position, and detection sequence recorded in the detection location information, the position of each detection point on the PVC membrane coating surface and the positional arrangement relationship between each detection point are determined. Following the acquisition sequence of the coating spectral information, the acquisition correspondence between the coating spectral information and each detection point is checked item by item. The coating spectral information obtained from each fixed acquisition channel (a fixed acquisition channel refers to a spectral acquisition path divided along the width direction of the PVC membrane, corresponding one-to-one with the fixed membrane width position and continuously acquiring the reflected light from the corresponding detection point) under the same acquisition sequence is configured to the corresponding detection point of each fixed acquisition channel. During the configuration of the coating spectral information, the band order and spectral response of each band in the coating spectral information remain unchanged, and each detection point, its positional arrangement relationship, and the corresponding coating spectral information are recorded together to form membrane spectral calibration data.

[0052] Furthermore, the acquisition of PVC film coating spectral information and detection position information involves continuously moving the PVC film along its length, using a detection path covering the width of the PVC film coating as the acquisition range for coating spectral information. A stable light source illuminates the PVC film coating surface, and a spectral acquisition probe receives the reflected light returned from each detection point. The intensity of the reflected light is recorded in wavelength order to obtain coating spectral information including the acquisition sequence, acquisition time, band sequence, and spectral response of each band. Simultaneously, a position encoder records the PVC film movement distance, and based on the acquisition position of the spectral acquisition probe in the width direction of the PVC film, the corresponding film length position and film width position are determined for each spectral acquisition. Detection points are set according to the acquisition sequence to obtain detection position information including the detection point position, film length position, film width position, and detection sequence.

[0053] It should be noted that the spectral acquisition probe adopts a line scan acquisition method that extends along the width of the PVC film. A stable light source illuminates the transverse detection line on the PVC film coating surface at the same acquisition time. The spectral acquisition probe divides the transverse detection line into multiple fixed acquisition channels, each corresponding to a film width position. The position encoder outputs equidistant trigger signals according to the movement distance of the PVC film. Each equidistant trigger signal controls the spectral acquisition probe to complete one transverse detection line acquisition, and the movement distance of the PVC film is determined as the film length position, and the position corresponding to the fixed acquisition channel is determined as the film width position. The film length position and the film width position together determine the detection point. Continuous acquisition forms transverse detection lines distributed sequentially along the length direction of the PVC film, so that each detection point covers the length and width directions of the PVC film coating, and maintains the correspondence between the acquisition time, acquisition order, detection point position and the spectral response of each band.

[0054] S1.2 Perform position misorder verification and misordered spectrum realignment correction on the membrane surface spectral calibration data, and output the membrane surface position correction data.

[0055] Specifically, the verification process uses the detection points, their arrangement, acquisition order, and detection sequence in the membrane surface spectral calibration data as the verification criteria. It checks each adjacent detection point's acquisition order along the arrangement to ensure continuous change with the detection sequence, while simultaneously verifying that the membrane length and width positions match the transverse detection line and the PVC membrane's movement direction. If a jump, reversal, or repetition in the acquisition order occurs, the coating spectral information with the misaligned position is identified. Using the acquisition time, the PVC membrane movement distance recorded by the position encoder, and the membrane width position corresponding to the fixed acquisition channel, the detection point corresponding to the misaligned coating spectral information is re-determined. The misaligned coating spectral information is then adjusted to the re-determined detection point, and the acquisition order, detection sequence, and arrangement of adjacent detection points are verified until all coating spectral information in the membrane surface spectral calibration data is consistent with the detection point, at which point the membrane surface position correction data is output.

[0056] Furthermore, to re-determine the detection point corresponding to the misaligned coating spectral information, the position encoder is searched for the PVC film movement distance recorded under the same equidistant trigger signal at the time of coating spectral information acquisition. The PVC film movement distance is determined as the film length position, and the film width position is determined according to the fixed acquisition channel that generates the coating spectral information. The film length position and film width position are used together to locate the unique detection point. When there are multiple records at the same acquisition time, they are matched one by one according to the acquisition order and the generation order of the equidistant trigger signal, so as to return the misaligned coating spectral information to the corresponding detection point.

[0057] S1.3. Arrange the coating spectral information in the film position correction data according to the positional arrangement relationship to generate coating position spectral data.

[0058] Specifically, the detection points in the membrane position correction data are divided into corresponding membrane length positions according to their positional arrangement. Within the same membrane length position, the corresponding coating spectral information is arranged according to the membrane width position order, so that the coating spectral information in the same transverse detection line maintains continuity in the width direction. Each membrane length position is arranged sequentially according to the PVC membrane movement direction, so that the coating spectral information in adjacent transverse detection lines maintains continuity in the length direction. During the arrangement process, the band order, spectral response of each band, membrane length position, membrane width position, and positional arrangement relationship corresponding to each detection point are retained, and the continuity relationship in the width direction and length direction is incorporated into the arrangement order of the coating spectral information to generate coating position spectral data.

[0059] S2. Perform film surface spectral difference identification on the coating position spectral data to obtain the base film reference position and coating coverage position. Extract the base film spectral features of the PVC film from the base film reference position and match the base film spectral features to the coating coverage position to generate the base film intrinsic spectral data.

[0060] S2.1. The PVC film band information and coating band information corresponding to each detection point in the coating position spectral data are segmented, classified and combined, and the dual-band response data of the film surface is output.

[0061] Specifically, based on the complete band sequence corresponding to each detection point, and according to the differences in the characteristic peak positions and peak shapes formed by the PVC film material composition and coating composition in the spectral curves, continuous bands with characteristic peak positions of PVC film are classified as PVC film band information, and continuous bands with characteristic peak positions of coating are classified as coating band information. During the segmentation and classification process, the wavelength position, spectral response, and band order corresponding to each band are retained. Furthermore, based on the repetitive response of the reflectance spectra of uncoated PVC film and coating material of the same batch at the same wavelength position, transition bands between adjacent characteristic peak positions are classified. Transition bands that only appear repeatedly in the reflectance spectrum of uncoated PVC film and have the same peak shape direction are classified as PVC film band information. The segment information is divided into two parts. Transition bands that appear repeatedly in the reflection spectrum of the coating material and have the same peak shape direction are classified into the coating band information. Transition bands that appear repeatedly in both the reflection spectrum of the uncoated PVC film and the reflection spectrum of the coating material or have overlapping characteristic peaks are marked with overlap marks. Transition bands with overlap marks only retain wavelength position, spectral response and band order, and are not classified into PVC film band information or coating band information. After the segmentation and classification are completed, the PVC film band information and coating band information corresponding to the same detection point are combined and recorded based on the detection point as the same point combination reference, so that each detection point has corresponding PVC film band information, coating band information and spectral response, and outputs the film surface dual-band response data.

[0062] Furthermore, the differences in the characteristic peak positions and peak shapes formed by the PVC film material components and coating components in the spectral curves were determined by collecting the reflection spectra of the same batch of uncoated PVC film and coating materials under the same light source intensity, acquisition distance, and band order as the PVC film coating. The reflection spectra obtained from multiple acquisitions were overlapped according to wavelength position, and the spectral peaks that recurred and had stable positions were retained. The wavelength position, peak shape changes, and adjacent band continuity of the corresponding spectral peaks were recorded. The spectral peaks that recurred stably in the same batch of uncoated PVC film were identified as the characteristic peak positions of the PVC film, and the spectral peaks that recurred stably in the coating material and did not coincide with the characteristic peak positions of the PVC film were identified as the characteristic peak positions of the coating. The differences in wavelength position and peak shape between the characteristic peak positions of the PVC film and the coating were used as the basis for segmenting and classifying the PVC film band information and the coating band information.

[0063] It should be noted that the PVC film coating retains an uncoated reference band extending continuously along the length of the PVC film on one side of the film width direction. The uncoated reference band and the PVC film coating use the same batch of PVC film. The detection points in the uncoated reference band only present PVC film band information. The detection points in the uncoated reference band serve as the source of the base film reference position, and the detection points in the PVC film coating serve as the source of the coating coverage position, so that both the base film reference position and the coating coverage position have a clear basis for the film surface position. The uncoated reference band covers multiple fixed acquisition channels in the width direction of the PVC film, so that each transverse detection line contains multiple uncoated reference band detection points. Different uncoated reference band detection points within the same transverse detection line respectively form PVC film band information. The PVC film band information in different uncoated reference band detection points is used to confirm the recurring peak position and peak shape, and to form a common spectral response corresponding to the same film surface length position.

[0064] S2.2 Perform synchronous difference comparison on the PVC membrane band information and coating band information of adjacent detection points in the dual-band response data of the membrane surface to form spectral difference discrimination data.

[0065] Specifically, adjacent detection points are determined according to the positional arrangement of the retained dual-band response data of the membrane surface. Between each pair of adjacent detection points, the increase or decrease of spectral response, peak position shift, and peak shape continuity at the same wavelength position are checked along the band order of the PVC membrane band information and the coating band information, respectively. The direction and degree of change of the PVC membrane band information and the coating band information in the same pair of adjacent detection points are recorded synchronously, distinguishing between cases where the PVC membrane band information changes alone, the coating band information changes alone, and cases where both types of band information change together. The adjacent detection points, wavelength positions, direction of change, degree of change, and peak shape continuity are collectively collected to form spectral difference discrimination data.

[0066] S2.3. Based on the spectral difference discrimination data, the spectral difference position of the detection point is calibrated, and the base film reference position and coating coverage position are output.

[0067] Specifically, the spectral difference discrimination data collected from the detection points includes records of changes in PVC film band information and coating band information between adjacent detection points. Detection points where the PVC film band information maintains continuous peak positions and shapes, and where the coating band information does not form continuous characteristic peaks, are designated as base film reference positions. Detection points where the PVC film band information is present and the coating band information forms continuous characteristic peaks are designated as coating coverage positions. During the spectral difference position calibration process, the film length position, film width position, and positional arrangement relationship corresponding to the detection points are retained.

[0068] Furthermore, the formation of continuous characteristic peaks in the coating band information means that consecutive adjacent detection points within the same transverse detection line all exhibit spectral responses with the same peak shape direction at the coating characteristic peak position. The absence of continuous characteristic peaks in the coating band information means that the detection points in the uncoated reference band do not exhibit peak shapes consistent with the reflection spectrum of the coating material at the coating characteristic peak position. The maintenance of continuous peak positions and peak shape in the PVC film band information means that the characteristic peak positions of the PVC film in consecutive adjacent detection points remain consistent, and the rising and falling directions of the spectral responses on both sides of the characteristic peak position of the PVC film remain consistent.

[0069] S2.4 Extract the spectral response of the base film reference position from the spectral data of the coating position, and collect the PVC film band information in the spectral response to form the base film spectral feature data.

[0070] Specifically, the base film reference position is divided into corresponding transverse detection lines according to the film surface length position. Using the film surface length position and film surface width position retained by the base film reference position, the spectral response corresponding to the base film reference position within the same transverse detection line in the coating position spectral data is locked. The spectral responses corresponding to each base film reference position within the same transverse detection line are expanded according to the band order, and the PVC film band information in the spectral response is retained. The peak position, peak shape and spectral response changes that occur repeatedly and remain continuous within the same transverse detection line are attributed to the common spectral characteristics of the PVC film, and the spectral responses that only appear at a single base film reference position and do not form continuous changes are excluded. The common spectral characteristics, band order, film surface length position and base film reference position of the PVC film are recorded together to form the base film spectral characteristic data.

[0071] Furthermore, the common spectral characteristics of the PVC membrane are obtained by arranging the PVC membrane band information at each base membrane reference position within the same transverse detection line according to the same wavelength position, retaining the recurring peak positions and peak shapes at each base membrane reference position, and averaging the spectral responses of each base membrane reference position at the same wavelength position to form a common spectral response corresponding to the same membrane length position; different membrane length positions form corresponding common spectral responses, so that the base membrane spectral characteristic data retains the spectral changes generated by the PVC membrane along the length direction.

[0072] S2.5. According to the positional arrangement relationship in the detection position information, the spectral characteristic data of the base film are matched with the coating coverage position one by one to generate the intrinsic spectral data of the base film.

[0073] Specifically, based on the film length position retained at the coating coverage location, the transverse detection line to which the coating coverage location belongs is determined in the positional arrangement relationship of the detection location information; the base film spectral feature data corresponding to the same film length position is configured to each coating coverage location within its respective transverse detection line, so that each coating coverage location has base film spectral feature data collected from the same transverse detection line; during the configuration process, the band order, common spectral features of the PVC film, film length position, and film width position of the coating coverage location in the base film spectral feature data are retained; after completing the item-by-item pairing of base film spectral feature data and coating coverage location within each transverse detection line, the base film reference position, base film spectral feature data, coating coverage location, and positional arrangement relationship are recorded together to generate the base film intrinsic spectrum data.

[0074] It should be noted that the intrinsic spectral data of the base film is not configured by assigning the same base film spectral feature data to all coating coverage positions. Instead, according to the film surface length position retained at the coating coverage position, the base film spectral feature data corresponding to the same film surface length position is configured to each coating coverage position within the corresponding transverse detection line. Different film surface length positions form corresponding common spectral responses, so that the base film spectral feature data retains the spectral changes generated by the PVC film along the length direction, and each coating coverage position has base film spectral feature data collected from the same transverse detection line.

[0075] S3. Based on the intrinsic spectrum data of the base film, the spectral features of the coating position spectral data are stripped to form the coating difference spectral data. Then, referring to the arrangement relationship of the coating coverage position in the detection position information, the coating difference spectral data is mapped to the coverage response position to generate the coating coverage spectral data.

[0076] S3.1. Referring to the band order of the intrinsic spectrum data of the base film, the spectral response corresponding to the coating coverage position in the spectral data of the coating position is arranged side by side with the intrinsic spectrum data of the base film to form spectral stripping reference data.

[0077] Specifically, based on the film length and width positions retained at the coating coverage location, the spectral response of the corresponding coating coverage location is locked in the spectral data of the coating location, and the intrinsic spectrum data of the base film paired with the corresponding coating coverage location is called up item by item; referring to the wavelength position and band order in the intrinsic spectrum data of the base film, the spectral response of the coating coverage location is rearranged according to the same wavelength position, so that the spectral response of the coating coverage location and the spectral response in the intrinsic spectrum data of the base film form a set of double-column records at each wavelength position; the double-column records are sequentially connected according to the band order of the intrinsic spectrum data of the base film, and the coating coverage location, the reference position of the base film, the film length position, the film width position, the wavelength position, and the spectral response are retained to form spectral stripping reference data.

[0078] S3.2. Perform amplitude ratio statistics on the spectral response in the same band of the spectral stripping reference data to determine the base film response ratio.

[0079] Specifically, for each coating coverage location, the spectral response corresponding to the coating coverage location and the spectral response in the intrinsic spectrum data of the base film are obtained according to the wavelength position. The spectral response at the same wavelength position in the intrinsic spectrum data of the base film is set as the unit response. The multiple of the spectral response corresponding to the coating coverage location relative to the unit response is determined to form a band amplitude ratio. No band amplitude ratio is formed when the spectral response in the intrinsic spectrum data of the base film is zero. The band amplitude ratios formed within the PVC film band information for the same coating coverage location are arranged in numerical order, and the band amplitude ratio in the middle of the arrangement is selected as the base film response ratio corresponding to the coating coverage location.

[0080] It should be noted that the base film response ratio only uses the wavelength positions in the PVC film band information that can stably reflect the spectral changes of the PVC film. The wavelength positions that can stably reflect the spectral changes of the PVC film are those wavelength positions in the reflectance spectra of uncoated PVC films in the same batch that repeatedly show the characteristic peaks of the PVC film, and in the reflectance spectra of the coating material that do not form the characteristic peaks of the coating. The wavelength positions in which the coating material forms the characteristic peaks of the coating are not included in the band amplitude ratio statistics to avoid the coating spectral response from being included in the base film response ratio. Furthermore, transition bands with overlapping markings are not included in the PVC film band information and are not included in the band amplitude ratio statistics.

[0081] Furthermore, the amplitude ratio of the bands at the middle position is determined after the amplitude ratios of multiple bands corresponding to the same coating coverage position are arranged in numerical order; by selecting the amplitude ratio of the bands at the middle position, the amplitude ratio of a single band at both ends of the numerical order arrangement is not directly determined as the base film response ratio.

[0082] S3.3 Adjust the spectral response of the intrinsic spectrum data of the base film at each coating coverage position according to the base film response ratio to form the base film corrected spectral data.

[0083] Specifically, for each coating coverage location, the spectral response of each wavelength position in the intrinsic spectrum data of the base film is scaled proportionally according to the base film response ratio corresponding to the coating coverage location. The intrinsic spectrum data of the base film paired with the corresponding coating coverage location is adjusted according to the corresponding base film response ratio, so that each wavelength position in the intrinsic spectrum data of the base film maintains the original band order and peak shape relationship, and the adjusted spectral response conforms to the response amplitude presented by the coating coverage location in the PVC film band information. The adjusted spectral response of each wavelength position is recorded together with the coating coverage location, film length position, film width position and band order to form the base film correction spectral data.

[0084] S3.4 Remove the spectral response of the coating coverage location from the coating location spectral data in the base film correction spectral data, and output the coating difference spectral data.

[0085] Specifically, for each coating coverage location, the spectral response in the coating location spectral data is matched wavelength-by-wavelength with the spectral response in the base film correction spectral data using the film length location, film width location, and wavelength location. The spectral response of the base film correction spectral data at the same wavelength location is subtracted from the spectral response at each wavelength location in the coating location spectral data, and the spectral response retained after subtraction is determined as the coating difference spectral response. Wavelength locations with negative values ​​after subtraction are recorded as having no coating difference spectral response to avoid the base film correction spectral data exceeding the coating location spectral data and causing a reverse spectral response. The coating difference spectral responses at each wavelength location are arranged according to the band order in the coating location spectral data, and the coating coverage location, film length location, and film width location are retained to output the coating difference spectral data.

[0086] S3.5. Based on the arrangement of coating coverage positions in the detection position information, perform coverage position localization on the coating difference spectral data and output coverage response localization data.

[0087] Specifically, using the film length and width positions retained from the coating coverage location, detection points with identical film length and width positions are identified in the detection location information, and their sequence numbers in the position arrangement are simultaneously determined. The coating difference spectral response of the corresponding coating coverage location in the coating difference spectral data is calibrated to the determined detection point, and the consistency between the coating coverage location, detection point, film length position, and film width position is verified. Only one detection point and one sequence number are retained for the same coating difference spectral response, and the coating difference spectral response, coating coverage location, detection point, and sequence number are recorded together to output the coverage response positioning data.

[0088] Furthermore, to verify the consistency between the coating coverage location, detection point, film length location, and film width location, the film length and width locations retained at the coating coverage location are compared item by item with the film length and width locations recorded at the detection points in the detection location information. If the film length and width locations of the coating coverage location and the detection point are the same, and the sequence number of the detection point in the position arrangement relationship is unique, then the coating coverage location and the detection point are determined to be consistent. If the film length and width locations are different, the detection point is missing, or the same coating coverage location corresponds to multiple detection points, then the coating coverage location and the detection point are determined to be inconsistent, and a unique detection point is re-determined based on the film length, width, and position arrangement relationship in the detection location information.

[0089] S3.6 Arrange the coating difference spectral data according to the location order and adjacent relationships of the coverage response positioning data to generate coating coverage spectral data.

[0090] Specifically, by combining the film length position, film width position, and sequence number of each detection point in the coverage response positioning data, the coating difference spectral data is divided into corresponding film length positions, and the coating difference spectral responses are arranged in order of sequence number from front to back within the same film length position. Detection points with consecutive sequence numbers within the same film length position are determined as adjacent detection points in the width direction, and detection points with the same film width position within adjacent film length positions are determined as adjacent detection points in the length direction. The adjacent detection points in the width direction and adjacent detection points in the length direction are recorded into the corresponding coating difference spectral data, so that the sequence number and film adjacency relationship are preserved for each coating coverage position. During the position sequence arrangement and adjacency relationship addition process, the coating difference spectral response, band order, coating coverage position, detection point, film length position, and film width position remain unchanged, generating coating coverage spectral data.

[0091] Furthermore, the adjacent relationship supplementation is based on each coating coverage position as the center. Coating coverage positions with consecutive serial numbers within the same film surface length position are recorded as adjacent positions in the width direction, and coating coverage positions with the same film surface width position within adjacent film surface length positions are recorded as adjacent positions in the length direction. Detection points with uncoated reference bands and no coating coverage positions are not included in the adjacent relationship supplementation to avoid connecting coating difference spectral responses across uncoated positions. Adjacent positions in the width direction and adjacent positions in the length direction are recorded together in the corresponding coating difference spectral data to maintain the actual continuity of the PVC film coating on the film surface in the coating coverage spectral data.

[0092] It should be noted that this scheme utilizes the intrinsic spectral data of the base film and the spectral response corresponding to the coating coverage location to form spectral stripping reference data. It then adaptively corrects the influence of the base film spectrum at different coating coverage locations by using the base film response ratio, ensuring that the corrected base film spectral data closely matches the actual response of the PVC film at each coating coverage location. After removing the corrected base film spectral data from the coating location spectral data, the coating difference spectral data can centrally retain the spectral changes caused by variations in coating thickness, continuous coverage, and local defects, reducing the interference of PVC film material condition and surface position differences on coating detection. The coverage response positioning data further restores the coating difference spectral response to the corresponding detection point and supplements the width and length adjacent relationships, enabling the coating coverage spectral data to simultaneously maintain coating spectral changes, film surface position order, and actual continuity, improving the accuracy of subsequent adjacent spectral comparison, regional response segmentation, and local anomaly location.

[0093] S4. The spectral angle matching algorithm is used to perform spectral shape comparison on adjacent coating coverage positions in the coating coverage spectral data to obtain the correlation of spectral changes. Based on the correlation of spectral changes, the coating coverage spectral data is segmented and organized into regional response segments, and the coating spectral fingerprint data is output.

[0094] S4.1 According to the arrangement of coating coverage positions, classify the spectral responses of adjacent coating coverage positions in the coating coverage spectral data into the same spectral group, and output the adjacent coverage spectral data.

[0095] Specifically, adjacent coating coverage positions are located item by item along the width and length adjacent relationships recorded in the coating coverage spectral data; two consecutively numbered coating coverage positions within the same film length position are assigned to the same width spectral group, and two coating coverage positions with the same film width position within adjacent film length positions are assigned to the same length spectral group; independent spectral groups are established for the same coating coverage position with adjacent coating coverage positions in the width and length directions, respectively, and spectral groups are established for detection points that do not cross the uncoated reference band or have no coating coverage position; adjacent coating coverage positions are recorded in each spectral group according to the order of coating coverage positions, and the corresponding spectral response, wavelength position, band order, film length position, and film width position are retained, and adjacent coverage spectral data are output.

[0096] S4.2 Convert the spectral response of each band in adjacent coverage spectral data into spectral shape vectors, and calculate the spectral angle between adjacent spectral shape vectors.

[0097] Specifically, the spectral response in this scheme uses the coating differential reflectance values ​​at each wavelength position. The coating differential reflectance value is the value retained after removing the reflectance values ​​at the same wavelength position from the base film correction spectral data of the reflectance values ​​at the coating position spectral data. For each width direction spectral group and length direction spectral group, according to the band order in the adjacent coverage spectral data, the coating differential reflectance values ​​at each wavelength position of one coating coverage position are arranged into a spectral vector, and the coating differential reflectance values ​​at the same wavelength position of adjacent coating coverage positions are arranged into another spectral vector. The two spectral vectors use the same number of wavelength positions and band arrangement order, and only the wavelength positions where both coating coverage positions have coating differential reflectance values ​​are retained. The normalized inner product of the adjacent spectral vectors is calculated, and an inverse cosine transformation is performed on the normalized inner product to obtain the spectral angle between the adjacent spectral vectors.

[0098] The formula for calculating the spectral angle is:

[0099] ;

[0100] in, Indicates the sequence number of the current coating coverage location. Indicates the relationship with the first The number of the next coating coverage location adjacent to the first coating coverage location. Indicates the first The coating coverage location is adjacent to the first... The spectral angle between the locations covered by the coating Indicates the wavelength position number. This indicates the number of wavelength positions involved in the spectral alignment. Indicates the first The coating coverage location is at the first Differential reflectance values ​​of the coating at each wavelength position. Indicates the first The coating coverage location is at the first Differential reflectance values ​​of the coating at each wavelength position.

[0101] S4.3 Determine the degree of spectral continuity and spectral variation between adjacent coating coverage locations based on the spectral angle, and integrate them into adjacent spectral variation data.

[0102] Specifically, for each spectral group in the width direction and the spectral group in the length direction, the cosine value corresponding to the spectral angle is determined as the degree of spectral continuity, and the complement of the degree of spectral continuity relative to the complete continuity state is determined as the degree of spectral change. When the spectral angle decreases, the degree of spectral continuity increases and the degree of spectral change decreases; when the spectral angle increases, the degree of spectral continuity decreases and the degree of spectral change increases. The spectral angle, the degree of spectral continuity, the degree of spectral change, the coverage position of adjacent coatings, the direction of spectral groups and their arrangement are recorded together and integrated into adjacent spectral change data.

[0103] S4.4 According to the arrangement of adjacent coating coverage positions, the degree of spectral continuity and the degree of spectral change in adjacent spectral change data are sequentially connected in series to output the correlation relationship of spectral changes.

[0104] Specifically, according to the spectral group directions recorded in adjacent spectral change data, the width direction spectral group and the length direction spectral group are arranged separately. The width direction spectral group is connected sequentially according to the arrangement number of the coating coverage position under the same film surface length position, and the length direction spectral group is connected sequentially according to the film surface length position of the coating coverage position under the same film surface width position. Every two adjacent coating coverage positions form a spectral change relationship, and the degree of spectral continuity and spectral change is preserved in the spectral change relationship. The spectral change relationships sharing the same coating coverage position are continuously connected according to the position arrangement order, and the spectral change correlation relationship is output.

[0105] S4.5. Based on the correlation of spectral changes, confirm the continuous change boundary of the coating coverage spectral data and obtain the regional response boundary data.

[0106] Specifically, each segment of the spectral variation relationship is examined along both the width and length directions. The spectral continuity and variation in each segment are compared with the spectral continuity and variation in the preceding and following segments in the order of the spectral variation relationship. If the spectral variation in the current segment is simultaneously higher than that in both the preceding and following segments, and the spectral continuity in the current segment is simultaneously lower than that in both segments, then the two phases corresponding to the current spectral variation relationship are... The locations of adjacent coating coverage positions are defined as continuous change boundaries; adjacent coating coverage positions that do not meet the conditions for defining continuous change boundaries continue to be retained in the same continuous region; the starting and ending coating coverage positions in the width and length directions of the coating coverage spectral data are recorded as outer position markers. The outer position markers are only used to limit the film surface detection range of the coating coverage spectral data and are not used as continuous change boundaries between adjacent coating coverage positions, nor are they used to segment coating coverage positions where the degree of spectral continuity and spectral change is continuous; the continuous change boundaries, outer position markers, coating coverage positions and arrangement relationships are recorded together to output the regional response boundary data.

[0107] Furthermore, the continuous variation boundaries in the width direction are connected according to the film surface length position, and the continuous variation boundaries in the length direction are connected according to the film surface width position; when the continuous variation boundaries in the width direction and the continuous variation boundaries in the length direction intersect each other, the boundary range formed by the intersection is used as the internal boundary of the response segment; when the continuous variation boundary extends to the start or end position of the film surface detection range, the corresponding outer position mark is used as the end position of the response segment range; the edge coating coverage position where no continuous variation boundary is formed and the spectral continuity and spectral variation degree remain continuous is retained in the same response segment as the internal coating coverage position where the position is continuous.

[0108] S4.6. Use the regional response boundary data to segment the coating coverage spectral data to form regional response segment data, and combine the correlation between each response segment and spectral change in the regional response segment data segment by segment to output the coating spectral fingerprint data.

[0109] Specifically, based on the continuous change boundary and outer boundary recorded in the regional response boundary data, coating coverage positions located between the same width and length direction boundaries and maintaining film surface adjacency are classified into the same response segment. For each response segment, the starting coating coverage position, ending coating coverage position, inner coating coverage position, coating differential reflectance value, band order, film surface length position, and film surface width position are recorded to form regional response segment data. According to the coating coverage positions included in each response segment, the spectral continuity and spectral change degree corresponding to the inside and the boundary of the response segment are determined in the spectral change correlation, and the spectral continuity and spectral change degree are configured to the corresponding response segments. Each response segment maintains the arrangement order according to the film surface length position and film surface width position, and the coating spectral fingerprint data is output.

[0110] It should be noted that this scheme accurately distinguishes between continuous and consistent spectral changes and local abrupt changes in PVC film coatings by using spectral change correlation and regional response boundary data. This enables the coating spectral fingerprint data to reflect the continuity of the area covered by the coating and the location of abnormal boundaries, reducing the interference of single-point spectral fluctuations on uniformity judgment and improving the accuracy of identifying the regional consistency of PVC film coatings and locating local anomalies.

[0111] S5. Identify the regional consistency and local anomalous states of the PVC film coating from the coating spectral fingerprint data, and collect the regional consistency and local anomalous states into the detection location information, and output the PVC film coating detection data.

[0112] S5.1 Perform continuous state analysis on the degree of spectral continuity of each response segment in the coating spectral fingerprint data and the degree of spectral change between adjacent response segments, and output segmented continuous state data.

[0113] Specifically, the order of each response segment is determined according to the length, width, and arrangement of the film surface. The continuity of the spectral pattern between adjacent coating positions within each response segment is examined. A complete record of the spectral continuity and continuous coating positions indicate continuous spectral continuity; a missing record or interrupted connection between coating positions indicates interrupted spectral continuity. The degree of spectral change between adjacent response segments is examined based on the coating positions on both sides of the common boundary. A continuous spectral change is defined as the two coating positions corresponding to the degree of spectral change aligning with the coating positions on both sides of the common boundary; a missing record or discrepancy between the two coating positions corresponding to the degree of spectral change and the coating positions on both sides of the common boundary indicates discontinuous spectral change. Segment continuity status data is then output.

[0114] Furthermore, in addition to checking the record connection relationship of the spectrum continuity and spectrum change, the continuous state analysis also judges the continuity of the response segments according to the actual values. The average value of the spectrum continuity within each response segment is recorded as the continuity level of the response segment, and the spectrum change corresponding to the common boundary of adjacent response segments is recorded as the boundary change level. The continuity level of the response segment is compared with the boundary change level of the common boundary on both sides of the response segment. When the continuity level of the response segment is higher than the boundary change level of the common boundary on both sides, the spectrum continuity is determined to be continuous. When the continuity level of the response segment is not higher than the boundary change level of the common boundary on either side, the spectrum continuity is determined to be interrupted. The boundary change level is compared with the continuity level of the response segment on one side of the common boundary and the continuity level of the response segment on the other side of the common boundary. When the boundary change level is lower than the continuity levels of the response segments on both sides of the common boundary, the spectrum change is determined to be continuous. When the boundary change level reaches or exceeds the continuity level of the response segment on either side of the common boundary, the spectrum change is determined to be discontinuous.

[0115] S5.2 According to the segmented continuous state data, the response segments in which the continuity and variation of the spectral shape are maintained are identified as regional consistent states, and the response segments in which the continuity of the spectral shape is interrupted and the spectral variation between adjacent response segments are identified as local abnormal states.

[0116] Specifically, the continuity of spectral continuity and the continuity of spectral variation are read segment by segment from the continuous state data. When the spectral continuity within a response segment remains continuous, and the spectral variation between the response segment and adjacent response segments remains continuous, the response segment is determined to be in a region-consistent state. When there is an interruption in the spectral continuity within a response segment, the response segment to which the interruption belongs is determined to be in a local anomalous state. When there is a discontinuous position in the spectral variation between adjacent response segments, the response segment connected by the discontinuous position is determined to be in a local anomalous state. Both the region-consistent state and the local anomalous state retain the corresponding response segment, coating coverage position, film length position, film width position, and arrangement relationship.

[0117] S5.3. Collect the regional consistency status and local abnormal status into the detection location information and output the PVC film coating detection data.

[0118] Specifically, based on the response segments, coating coverage location, film length location, and film width location retained for regional consistency and local anomaly states, the detection points with consistent location records are determined in the detection location information. Regional consistency states are recorded to each detection point included in the corresponding response segment, and local anomaly states are recorded to the detection points involved in the interruption of spectral continuity and the discontinuity of spectral change. The detection points with completed status records are arranged according to the positional arrangement relationship in the detection location information. Regional consistency states with continuous positions are summarized into a regional consistency distribution, and local anomaly states with continuous positions and their boundaries are summarized into a local anomaly distribution. The detection points, positional arrangement relationship, regional consistency distribution, and local anomaly distribution are collectively collected to output PVC film coating detection data.

[0119] Furthermore, the membrane surface state distribution summary connects detection points with the same state according to the width and length adjacent relationships in the detection location information; when continuously connecting detection points with consistent regional states, the membrane length position, membrane width position, and outer detection points covered by the consistent regional distribution are recorded; when continuously connecting detection points with local abnormal states, the membrane length position, membrane width position, and boundary detection points covered by the local abnormal distribution are recorded; when only a single detection point records a local abnormal state, the single detection point is recorded independently as a local abnormal position, so that the consistent regional distribution and the local abnormal distribution can correspond to the actual position on the PVC membrane coating surface.

[0120] This embodiment also provides a computer device applicable to the PVC film coating uniformity detection method based on spectral analysis, comprising: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the PVC film coating uniformity detection method based on spectral analysis as proposed in the above embodiment.

[0121] The computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0122] This embodiment also provides a storage medium storing a computer program, which, when executed by a processor, implements the PVC film coating uniformity detection method based on spectral analysis as proposed in the above embodiments. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0123] In summary, this invention improves the accuracy of identifying spectral changes in PVC film coatings by performing spectral feature stripping on the coating location spectral data using the intrinsic spectral data of the base film. With the influence of the base film spectrum weakened, spectral differences between different coating coverage locations caused by coating thickness, coverage continuity, and local defects can be more clearly preserved, reducing the interference of changes in PVC base film thickness, material composition, and light transmittance on the detection results. The coating difference spectral data can maintain the correspondence between coating changes and film surface positions, enabling stable differentiation between continuous coating areas and local abnormal areas. This provides an accurate data basis for coating area division, spectral fingerprint formation, and uniformity identification, thereby improving the reliability and positioning accuracy of PVC film coating uniformity detection.

[0124] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for detecting the uniformity of PVC film coatings based on spectral analysis, characterized in that: include, Collect the coating spectral information and detection location information of the PVC film coating, perform film surface position correlation on the coating spectral information according to the detection location information, and generate coating position spectral data; Perform spectral difference identification on the coating location spectral data to obtain the base film reference position and coating coverage position. The specific steps are as follows: The PVC film band information and coating band information corresponding to each detection point in the coating position spectral data are segmented, classified and combined, and the dual-band response data of the film surface is output. Synchronous difference comparison is performed on the PVC membrane band information and coating band information of adjacent detection points in the dual-band response data of the membrane surface to form spectral difference discrimination data; Based on the spectral difference discrimination data, the spectral difference position of the detection point is calibrated, and the base film reference position and coating coverage position are output. The spectral features of the PVC membrane are extracted from the base membrane reference position and matched to the coating coverage position to generate the intrinsic spectral data of the base membrane. The PVC film coating retains an uncoated reference band that extends continuously along the length of the PVC film on one side of the film width direction. The uncoated reference band and the PVC film coating use the same batch of PVC film. The detection points in the uncoated reference band only show the PVC film band information. The detection points in the uncoated reference band serve as the source of the base film reference position. Based on the intrinsic spectrum data of the base film, spectral features of the coating position spectral data are stripped to form coating difference spectral data. Then, referring to the arrangement relationship of the coating coverage position in the detection position information, the coating difference spectral data is mapped to the coverage response position to generate coating coverage spectral data. A spectral angle matching algorithm is used to perform spectral shape comparison on adjacent coating coverage positions in the coating coverage spectral data to obtain the correlation of spectral changes. Based on the correlation of spectral changes, the coating coverage spectral data is segmented and organized according to regional response, and the coating spectral fingerprint data is output. The system identifies regional consistency and local anomalous states of PVC film coatings from coating spectral fingerprint data, and aggregates these states into the detection location information to output PVC film coating detection data.

2. The method for detecting the uniformity of PVC film coating based on spectral analysis as described in claim 1, characterized in that: The specific steps for generating the spectral data of the coating location are as follows: Identify each detection point and its positional arrangement from the detection location information, and align the coating spectral information with each detection point to form film surface spectral calibration data; Perform position misorder verification and misordered spectrum realignment correction on the membrane surface spectral calibration data, and output membrane surface position correction data; The coating spectral information in the film position correction data is arranged into a position sequence according to the positional arrangement relationship to generate coating position spectral data.

3. The method for detecting the uniformity of PVC film coating based on spectral analysis as described in claim 2, characterized in that: The specific steps for generating the intrinsic spectrum data of the base film are as follows: The spectral response of the base film reference position is extracted from the spectral data of the coating position, and the PVC film band information in the spectral response is feature-collected to form the base film spectral feature data. Based on the positional arrangement in the detection location information, the spectral characteristic data of the base film are paired with the coating coverage location item by item to generate the intrinsic spectral data of the base film.

4. The method for detecting the uniformity of PVC film coating based on spectral analysis as described in claim 3, characterized in that: The specific steps for forming the coating difference spectral data are as follows: Referring to the band order of the intrinsic spectrum data of the base film, the spectral response corresponding to the coating coverage position in the spectral data of the coating position is arranged side by side with the intrinsic spectrum data of the base film to form spectral stripping reference data; The amplitude ratio of the spectral response in the same band in the spectral stripping reference data was statistically analyzed to determine the response ratio of the base film. The spectral response of the intrinsic spectrum of the base film at each coating coverage location is adjusted according to the base film response ratio to form the base film corrected spectral data; Remove the spectral response of the coating coverage location from the coating location spectral data in the base film correction spectral data, and output the coating difference spectral data.

5. The method for detecting the uniformity of PVC film coating based on spectral analysis as described in claim 4, characterized in that: The specific steps for generating the coating coverage spectral data are as follows: Based on the arrangement of coating coverage locations in the detection location information, coverage location is determined by the coating difference spectral data, and coverage response location data is output. The coating difference spectral data are arranged according to the location order and adjacent relationships of the coverage response location data to generate coating coverage spectral data.

6. The method for detecting the uniformity of PVC film coating based on spectral analysis as described in claim 5, characterized in that: The specific steps for obtaining the correlation of spectral changes are as follows: According to the arrangement of coating coverage locations, the spectral responses of adjacent coating coverage locations in the coating coverage spectral data are grouped into the same spectral group, and the adjacent coverage spectral data are output. The spectral responses of each band in adjacent coverage spectral data are converted into spectral shape vectors, and the spectral angle between adjacent spectral shape vectors is calculated. The degree of spectral continuity and spectral variation between adjacent coating coverage locations is determined based on the spectral angle, and then integrated into adjacent spectral variation data; Based on the arrangement of adjacent coating coverage positions, the degree of spectral continuity and the degree of spectral change in adjacent spectral change data are sequentially concatenated to output the correlation relationship of spectral changes.

7. The method for detecting the uniformity of PVC film coating based on spectral analysis as described in claim 6, characterized in that: The specific steps for generating the output coating spectral fingerprint data are as follows: Based on the correlation of spectral changes, the boundary of continuous variation in the spectral data of the coating coverage is confirmed, and regional response boundary data is obtained. The coating coverage spectral data is segmented using regional response boundary data to form regional response segmented data. The correlation between each response segment and spectral change in the regional response segmented data is then combined segment by segment to output the coating spectral fingerprint data.

8. The method for detecting the uniformity of PVC film coating based on spectral analysis as described in claim 7, characterized in that: The specific steps for identifying the regional consistency and local anomalies of the PVC film coating are as follows: The continuity of the spectral shape of each response segment in the coating spectral fingerprint data and the degree of spectral shape change between adjacent response segments are analyzed to output segmented continuous state data. Based on the segmented continuous state data, response segments that maintain a continuous degree of spectral continuity and spectral variation are identified as regionally consistent states, while response segments where the degree of spectral continuity is interrupted and response segments where the degree of spectral variation between adjacent response segments is discontinuous are identified as locally anomalous states.

9. The method for detecting the uniformity of PVC film coating based on spectral analysis as described in claim 1, characterized in that: The PVC film coating detection data is generated by recording the consistent state of the region and the abnormal state of the local area into the detection point and position arrangement relationship in the detection location information, and summarizing the distribution of the film surface state.

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