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CN-121977696-A - Determination method for displaying product chromaticity coordinate area under measurement of chromaticity instrument

CN121977696ACN 121977696 ACN121977696 ACN 121977696ACN-121977696-A

Abstract

The invention discloses a method for judging a chromaticity coordinate area of a display product under chromaticity instrument measurement, which comprises the steps of (1) judging chromaticity coordinate stability, (2) optimizing chromaticity target areas, (3) judging and optimizing chromaticity target areas, wherein aiming at the problems that a traditional stability judging mode is single-dimensional, CIE1931 original chromaticity coordinates are provided in a discrete data form with a wavelength interval of 1nm, sampling intervals are large, precision is limited, the traditional attribution judging aims at the problem that calculated amount of a chromaticity diagram with dense data points is large, and the like, constructing a minimum chromaticity ellipse according to a covariance matrix, judging chromaticity coordinate stability through space distribution characteristics of an analysis point set, adopting a piecewise polynomial interpolation fitting original chromaticity point, optimizing coordinate precision to 0.01nm, adopting a two-stage quick judging strategy, realizing candidate sector primary screening based on polar angles, and then accurately judging by using a local ray method in a local candidate sector obtained by the primary screening to finish target area positioning of chromaticity coordinates.

Inventors

  • ZHONG YUANSHENG
  • TANG LIHUA
  • HUANG WENCAI

Assignees

  • 广东产品质量监督检验研究院（国家质量技术监督局广州电气安全检验所、广东省试验认证研究院、华安实验室）

Dates

Publication Date
20260505
Application Date
20260402

Claims (9)

  1. 1. The method for judging the color coordinate area of the display product under the measurement of the colorimeter is characterized by comprising the following steps of: (1) And (3) chromaticity coordinate stability judgment: Adopting the characteristic value of the covariance matrix to correspond to the half-axis long square of the ellipse, constructing a minimum chromaticity ellipse corresponding to the rotation direction of the ellipse, regarding chromaticity coordinates U, V as a two-dimensional whole, and judging the whole stability of chromaticity coordinates by analyzing the space distribution characteristics of the point set; (2) Optimization of chromaticity target region: Fitting original chromaticity points by adopting piecewise polynomial interpolation, optimizing the precision of the coordinates of the discrete original chromaticity points from 1nm to 0.01nm of high-density chromaticity points, and matching the start and stop points of preset data points with the high-density chromaticity points by adopting a two-dimensional Euclidean distance; (3) Chromaticity target region attribution judgment optimization: The method comprises the steps of calculating a chromaticity target area center point by adopting an irregular polygon centroid calculation algorithm, dividing the chromaticity target area into a regular sector and a curve sector according to the center point, dividing the curve sector at equal intervals to form a sub-sector to complete pretreatment, adopting a two-stage rapid judging strategy, firstly realizing a preliminary screening sector on chromaticity coordinates to be detected based on polar angles, and then accurately judging in a local candidate sector obtained by preliminary screening by using a ray method.
  2. 2. The method of determining a chromaticity coordinate area of a display product as recited in claim 1, wherein the chromaticity coordinate stability determination in step (1) includes: The setting of the minimum chromaticity ellipse comprises the steps of collecting N groups of data, forming a covariance matrix by using an auto-covariance and a cross-covariance, integrating U, V fluctuation conditions of a single dimension and a double dimension of coordinates, enabling a characteristic value of the covariance matrix to correspond to a half-axis long square of the minimum chromaticity ellipse, enabling a characteristic vector to correspond to a rotation direction of the ellipse, and establishing a mapping relation between the covariance matrix and geometric parameters of the ellipse, and further comprising: (1-1-1) UV-associated fluctuation setup N sets of data (U j ,V j ) were collected, the fluctuation cases of the individual U, V single dimensions were detected with auto-covariances σ UU and σ VV of the U, V coordinates, the associated fluctuation cases of U and V were detected using cross-covariance σ UV 、σ VU , and the auto-covariances and cross-covariances were combined into a covariance matrix: (equation 1) (1-1-2) Setting a minimum chromaticity ellipse, namely, enabling eigenvalues of a covariance matrix to correspond to the half-axis long square of the minimum chromaticity ellipse, and enabling eigenvectors to correspond to the rotation direction of the ellipse; (1-1-3) covariance matrix eigenvalue calculation, wherein the solution eigenvalue of the covariance matrix is set as follows: (equation 2) Wherein I is an identity matrix, beta is a characteristic value of a covariance matrix, and two characteristic values beta 1、 β 2 and corresponding rotation angles are obtained by solving (Equation 3) (1-2) Calculating the minimum chromaticity elliptical area, namely introducing chi-square distribution quantiles, setting chromaticity confidence, calculating the minimum chromaticity elliptical half-axis length by combining eigenvalues of covariance matrix, and finally calculating the minimum chromaticity elliptical area, and further comprising: (1-2-1) setting a chromaticity confidence level, namely, introducing chi-square distribution quantiles, and setting a chromaticity confidence level ψ 2 (2) based on U, V two-dimensional degrees of freedom; the minimum chroma ellipse half-axis length calculation is carried out by setting a as a long half axis and b as a short half axis, and combining the eigenvalue of covariance matrix and the calculation formula of chroma confidence coefficient is as follows: (equation 4) (1-2-3) Calculation of minimum chromaticity elliptical area in combination with minimum chromaticity elliptical half-axis length, the calculated minimum chromaticity elliptical area is: (equation 5) (1-3) Judging the stability of chromaticity coordinates by comparing the threshold value with the minimum chromaticity elliptical area, if the stability is smaller than the stability threshold value, selecting the minimum chromaticity elliptical center as the final chromaticity coordinate point, further comprising: (1-3-1) calculating a minimum chromaticity ellipse center, namely taking a two-dimensional mean point of N groups of collected data as the minimum chromaticity ellipse center; And (1-3-2) stability judgment, namely setting a stability threshold, judging stability through comparison of the threshold and the minimum chromaticity elliptical area, if the stability threshold is smaller than the stability threshold, stabilizing, and selecting the minimum chromaticity elliptical center as the final chromaticity coordinate point.
  3. 3. The method of claim 2, wherein the stability threshold in step (1-3-2) is 10 -6 .
  4. 4. The method for determining a chromaticity coordinate area of a display product under measurement of a colorimeter according to claim 1, wherein the step (2) of fitting the original chromaticity point by using piecewise polynomial interpolation, optimizing the accuracy of the coordinates of the discrete original chromaticity point from 1nm to 0.01nm as a high-density chromaticity point, and matching the start-stop point of the preset data point with the high-density chromaticity point by using a two-dimensional euclidean distance, further comprises: Fitting the chromaticity curve, namely fitting original chromaticity points by adopting piecewise polynomial interpolation, setting each wavelength in a section as an independent cubic polynomial, enabling the curve to completely coincide with the original discrete points through continuous first derivative and second derivative, and adapting nonlinear change characteristics of the chromaticity contour; (2-1-2) optimizing the coordinate precision of the chromaticity point, namely performing interpolation calculation in each wavelength section by using independent cubic polynomials according to the result of chromaticity curve fitting, optimizing the precision to be 0.01nm of high-density chromaticity point, and improving the smoothness of the curve and the coordinate positioning precision; (2-1-3) positioning start-stop anchor points of chromaticity coordinates, namely, high-density chromaticity points are discrete but not continuous data with equal wavelength intervals, deviation exists between the start-stop points of preset data points of a chromaticity target area and the high-density chromaticity points, the start-stop points of the preset data points and the high-density chromaticity points are matched by adopting two-dimensional Euclidean distance, the chromaticity point with the minimum distance is selected as the start-stop anchor points, and a corresponding chromaticity coordinate sequence is extracted.
  5. 5. The method for determining a chromaticity coordinate area of a display product under measurement of a chromaticity instrument according to claim 1, wherein in the step (3), an irregular polygon centroid calculation algorithm is adopted to calculate a chromaticity target area center point, the chromaticity target area is split into a regular sector and a curve sector according to the center point, and the curve sector is divided into sub-sectors at equal intervals to complete preprocessing, and further comprising: (3-1-1) solving the center point of the chromaticity target area, namely decomposing the chromaticity target area into a plurality of triangles taking the origin as vertexes by adopting an irregular polygon centroid calculation algorithm, and calculating the integral centroid as the center point by area weighted average; (3-1-2) reconstructing a coordinate axis by taking the central point of the chromaticity target area as a reference, so as to facilitate the calculation of the polar angle; and (3-1-3) splitting the chromaticity target area, namely splitting the chromaticity target area into a regular sector and a curve sector according to a central point, collecting chromaticity points according to equal intervals of n aiming at the characteristics of dense chromaticity points and huge quantity of the curve sector to form sub-sectors, and generating a corresponding polar angle sequence by the target area, wherein the polar angles are uniformly converted into (0, 2 pi).
  6. 6. The method for determining a chromaticity coordinate area of a display product under measurement of a chromaticity instrument according to claim 1, wherein the step (3) adopts a two-stage fast determination strategy, and comprises the steps of firstly implementing a preliminary screening sector on chromaticity coordinates to be measured based on polar angles, and then accurately determining in a local candidate sector obtained by preliminary screening by using a ray method, and further comprising: (3-2-1) calculating the polar angle of the chromaticity point to be measured, calculating the polar angle of the chromaticity point to be measured by taking the central point as a pole, and unifying the polar angle to (0, 2 pi); (3-2-2) setting a floating point precision tolerance value, namely setting an extremely small floating point precision tolerance, controlling an error range and trowelling calculation errors because the floating point precision of the chromaticity point is too high and the floating point calculation has rounding errors, wherein the numerical value is easy to cause judgment logic abnormality; (3-2-3) candidate sector preliminary screening, namely rapidly judging an angle sector to which a chromaticity point to be detected belongs through a polar angle, and rapidly and initially screening a candidate region by using binary search rapid positioning sub-sectors aiming at a curve sector with a plurality of sub-sectors; and (3-2-4) determining and optimizing the regional attribution of the chromaticity target region, namely after the candidate sector is obtained based on polar angle preliminary screening, realizing the regional attribution of the chromaticity point to be measured in the local range by adopting a ray method, simplifying global traversal into local accurate determination, and effectively improving the determination efficiency of the regional attribution of the chromaticity point.
  7. 7. The method for determining a chromaticity coordinate area of a display product according to the measurement of a chromaticity apparatus as claimed in claim 6, wherein the tolerance of the minimum floating point precision in the step (3-2-2) is (1-3) ×10 -6 .
  8. 8. The method according to claim 1, further comprising the step of (4) determining whether the chromaticity target area is located within the chromaticity target area by determining whether the point is located within the chromaticity target area by a ray method.
  9. 9. The method of claim 8, wherein the determining step (4) of determining whether the point is located inside the chromaticity target region by using a ray method further comprises: The judgment of the intersection condition of the ray and the edge comprises the steps of using a ray method to emit an infinitely long ray from a chromaticity point to be detected to the right and the left of a chromaticity target area, judging all edges of the chromaticity target area, and judging the intersection condition of the ray and the edge on the upper side and the lower side of the ray through two end points of the edge; And (4-1-2) judging the attribution of the chromaticity target area, namely solving the intersection abscissa through linear interpolation based on the intersection relation of the edges and the rays, screening the effective intersection points in the positive direction of the rays, calculating the parity of the total number Z of the effective intersection points, judging whether the chromaticity point to be detected is in the chromaticity target area, if Z is an odd number, the chromaticity point to be detected is in the chromaticity target area, and if Z is an even number, the chromaticity point to be detected is outside the chromaticity target area.

Description

Determination method for displaying product chromaticity coordinate area under measurement of chromaticity instrument Technical Field The invention belongs to the technical field of colorimetry measurement and analysis, and particularly relates to a judging method for a chromaticity coordinate area of a display product under measurement of a colorimeter. Background In the development and production process of display products, the control requirements of color quality are increasingly improved. The high-precision spectroradiometer, the spectrum color brightness meter and other precise colorimetric measuring instruments are used as core equipment for quantitative detection of color parameters, and play a key role in a product quality control link. In order to meet the detection requirements of high efficiency, high precision and standardization of the modern display industry, the chromaticity detection technology is gradually developed from the traditional manual reading to the automatic data acquisition, analysis and processing and intelligent judgment. When a chromaticity instrument is utilized to automatically capture accurate chromaticity coordinates at a certain moment as detection data, the accurate chromaticity coordinates are easily affected by measurement ambiguity, data fluctuation and abnormal value interference, so that the reliability of a single sampling result is insufficient. Therefore, the stability of the sequence data can be evaluated by continuously collecting chromaticity coordinate data, and a representative effective value can be screened out as a final detection result. The data stability judgment is a key link for ensuring the measurement accuracy and the result reliability, and the common method mainly comprises KPSS, ADF, PP and DF-GLS test. Secondly, in the high-precision detection of display products, under the scenes of picture uniformity test, white balance calibration, color gamut consistency verification and the like, chromaticity coordinate region judgment is a core basic link. By mapping chromaticity data to the CIE1931 chromaticity diagram, whether the chromaticity data falls in a standard area or not is judged, and color qualification judgment and accuracy verification can be completed. Related technical requirements are clearly embodied in standards of JT/T597-2022 LED lane control sign, SJ/T11746-2019 ultra-high definition television display performance test method, SJ/T11141-2025 Light Emitting Diode (LED) display screen general specification and the like, however, factors such as ambient temperature and humidity, ambient light change, instrument calibration deviation, measurement angle error, abnormal data transmission and the like are easy to cause a measurement chromaticity point to fall outside a CIE1931 chromaticity diagram. For this purpose, an irregular area formed by chromaticity contour curves of the CIE1931 chromaticity diagram needs to be subjected to an inside and outside point determination, and a currently common algorithm is a ray method. However, the color detection of the display product based on the colorimeter still has a plurality of defects in terms of chromaticity coordinate stability analysis and region automatic judgment, namely (1) the traditional stability judgment mode has the limitation of independently judging the stability by separating chromaticity coordinates U and V (wherein U, V respectively correspond to an abscissa x-axis and an ordinate y-axis of chromaticity coordinates), the chromaticity coordinates are points of a two-dimensional chromaticity space, so that the stability which is shown when the chromaticity coordinates are taken as a whole in the two-dimensional chromaticity space cannot be accurately reflected, and (2) the CIE1931 original chromaticity coordinates are provided in the form of discrete data with a wavelength interval of 1nm, the sampling interval is large, the precision is limited, and obvious tooth distortion exists in a chromaticity contour curve formed. Meanwhile, measurement errors introduced by temperature and humidity, ambient light, instrument calibration, measurement angles, data transmission and the like are overlapped with contour distortion, so that obvious ambiguity exists in the boundary judgment of a chromaticity target area, color points nearby the boundary are difficult to accurately distinguish, and the requirements of high-precision analysis such as nanoscale color feature recognition and the like cannot be met, and therefore the precision of the color points is required to be optimized. (3) Global ray-based attribution determination is performed in complex irregular chromaticity regions such as CIE1931 chromaticity diagram, and particularly under the scene of dense data points or complex region division, intersection relations are required to be verified with each chromaticity coordinate point forming a target region in sequence, so that the calculation amount is huge and the time consumption is