Method and system for matching and adjusting the pigmentation of a sample coating to a target coating

Abstract

The present invention relates to a computer-implemented method for matching and adjusting the pigmentation of a target coating, the method comprising at least the following steps: - retrieving (202) a preliminary matching formula from a formula database comprising formulas for coating compositions having different pigmentations; - providing (203) a matching metric; and by using one or more processors: - calculating (203) a matching metric value for the preliminary matching formula; - judging, based on the magnitude of the matching metric value, whether the pigmentation is significantly improveable; in the event that the pigmentation is significantly improveable (209): - defining (210) a selection of at least one additional coloring base that may be eligible for further adjustment to the preliminary matching formula of the target coating; - calculating a matching metric value for each of the at least one additional coloring base; - publishing (214) a list of eligible additional coloring bases for the at least one additional coloring base via an output device. The present invention also relates to suitable systems and suitable computer-readable storage media.

Description

Technical Field

[0001] The present disclosure relates to a method and system for matching and adjusting the pigmentation of a sample coating to a target coating. Background Art

[0002] If color standards must be matched and coloring must be carried out, the number of coloring steps required is a decisive factor in the economic efficiency of the matching process. The appearance (i.e., the color and / or texture of the dried paint layer), also referred to below as "coating" or "color coating", depends largely on the coloring base used.

[0003] The color matching process is typically initiated by searching a database of existing color measurements and their corresponding formulas. A formula whose measured values ​​are close in color and / or pigmentation is then selected as the starting formula. If the pigmentation of the starting formula does not correspond to the pigmentation to be matched (i.e., the pigmentation of the target coating), the matching process typically takes longer. It also results in solutions of limited quality, such as residual color differences and / or metamerism, and ultimately poor reproducibility of the solution. Metamerism is a phenomenon where two colors match under an illuminant such as daylight (CIE standard illuminant D65, color temperature 6500K) but do not match under another illuminant, such as the light emitted by an incandescent bulb (CIE standard illuminant A, color temperature 2800K).

[0004] Due to wavelength-dependent absorption and scattering, each pigment included in a formulation changes the color of reflected light and produces a characteristic signature in its measured spectral remission curve. However, inexperienced colorists often lack the necessary expertise to determine which pigments are needed in a formulation to match a specific color. This is because multiple pigments are combined and their characteristic profiles overlap. Furthermore, a color matching system often contains dozens of different pigmented bases. For these reasons, interpreting remission curves requires experience and extensive training. Often, due to a lack of information, an incorrect combination of bases is used. Incorporating the correct combination of pigments into a formulation will help achieve better color matches in a shorter time.

[0005] Therefore, the present invention aims to provide a method for providing colorists with recommendations regarding the pigmentation of the desired formulation for a target coating. Based on a given starting formula, it should be possible to automatically suggest potential missing coloring bases to the colorist, hereinafter also referred to as preliminary matching formulas. Optionally, it can also suggest which coloring bases are redundant. Using the suggested modified starting formulas, the further color matching process can be more efficient and produce more stable and accurate solutions. Summary of the Invention

[0006] The present disclosure provides systems and methods having the features of the independent claims. Embodiments are subject matter of the dependent claims as well as the description and drawings.

[0007] Today, the color matching and adjustment process is based on the use of multi-angle spectrometers (e.g. I or XRite Digital color measurement is performed using a spectrometer (series of spectrometers). The reflectance of a color coating is measured from several geometries (illumination and viewing directions / angles). The typical measurement geometry is a fixed illumination angle of 45° measured relative to the normal of the coating surface and viewing angles of -15°, 15°, 25°, 45°, 75°, and 110°. Each angle is measured relative to the specular angle (i.e., the specular direction), which is defined as the outgoing direction at the same angle to the normal of the color coating surface as the incident direction of the corresponding light. It is also possible to keep the viewing angle constant and change the illumination angle.

[0008] Color measurements (e.g., relief curves and / or colorimetric data that can be derived therefrom) and their corresponding formulas are stored in a recipe database. The color matching process (i.e., matching and adjusting the color of a target coating) is typically initiated by searching such a database for existing color measurements and their corresponding formulas. A formula whose measurements are close in color, spectral curve, and optionally texture is then selected as a preliminary matching formula. A method is required to determine whether the pigmentation of the preliminary matching formula is sufficient to adequately match the target color. If the pigmentation is insufficient, a method is required to determine the optimal complementary pigment in order to improve the matching result of the target color.

[0009] In the context of the present disclosure, the terms "coloring base" and "pigment" are used synonymously. A coloring base is a dispersed pigment.

[0010] The present disclosure proposes a computer-implemented method for matching and adjusting the pigmentation of a target coating, the method comprising at least the following steps:

[0011] a) retrieving, via a communication interface, one (or more) preliminary matching formulas, hereinafter also referred to as starting formulas, from a formula database comprising formulas of coating compositions having different pigmentations;

[0012] b) providing a matching metric that describes the color difference and spectral similarity between a given (e.g., measured) relief curve for the target coating and a relief curve determined for the preliminary matching formula; and

[0013] By using one or more processors:

[0014] c) calculating a matching metric value for the preliminary matching formula based on the measured relief curve for the target coating and the relief curve determined for the preliminary matching formula;

[0015] d) adjusting the preliminary matching formula with respect to the included pigment concentrations in a manner that minimizes the matching metric;

[0016] e) evaluating a matching metric value of the adjusted preliminary matching formula;

[0017] f) judging whether the pigmentation of the adjusted preliminary matching formula can be significantly improved based on the magnitude of the matching metric value;

[0018] In cases where pigmentation can be significantly improved with the adjusted Primary Match formula:

[0019] g) defining a selection of at least one additional tinting base that may be eligible for further adjustment to the adjusted primary matching formula of the target coating, each additional tinting base being associated with a corresponding modified primary matching formula consisting of the adjusted pigmentation of the primary matching formula and the corresponding tinting base;

[0020] h) calculating, for each of the at least one additional color base, a matching metric value for the corresponding modified preliminary matching formula;

[0021] i) adjusting the modified preliminary matching formula with respect to the concentrations of the included pigments in such a way that the matching metric is minimized;

[0022] j) assigning each of the at least one additional color base to a corresponding one of the matching metric values ​​of the corresponding one of the adjusted modified preliminary matching formulas;

[0023] k) publishing, via an output device, a list of at least those additional coloring bases of the at least one additional coloring base whose associated adjusted modified preliminary matching formula has a relief curve that is more similar to the relief curve of the target coating with respect to the matching metric than the relief curve of the adjusted preliminary matching formula.

[0024] For example, the matching metric can be a weighted sum of dE* (a color difference metric) and dShape or dShape* (a spectral similarity metric) (as described below). Typically, the aim is to adjust the preliminary matching formula so that the color differences dE*, optionally also the texture differences, sparkle differences dS and granularity differences dG, and the spectral similarity metric dShape are minimized when all metrics are considered individually (i.e. alone). Further correction / adjustment of the preliminary matching formula is performed using a cost function that combines all those considered metrics, for example by adding all considered metrics together: dE* (or dL*+db*+da*)+dShape (optionally +dS+dG+...), possibly with each addition being appropriately weighted and minimizing the cost function accordingly.

[0025] Within the scope of the present disclosure, the terms "relief curve," "spectral relief curve," "spectral curve," and "reflectance curve" are used synonymously.

[0026] In order to adjust the preliminary matching formula in such a way that the matching metric value is minimized, a color adjustment algorithm based on a radiation transfer model (e.g., a physical model such as the Kubelka-Munk model (or a statistical model such as a neural network)) is used in the first step (step d). The color adjustment algorithm determines the concentration of the coloring base (or pigment) included in the preliminary matching formula to obtain the optimal (minimum) matching metric. It is also possible to set the concentration of the coloring base to zero. In this case, a coloring base is redundant or unnecessary.

[0027] The adjusted preliminary matching formula should be understood as a preliminary matching formula that is adjusted with respect to the matching metric; the modified preliminary matching formula should be understood as a preliminary matching formula with a coloring base added, and the adjusted modified preliminary matching formula is a modified preliminary matching formula that is further adjusted with respect to the matching metric.

[0028] The relief curve of the modified preliminary matching formula in step h) is predicted by a radiation transfer model (a physical model, such as the Kubelka-Munk model, or a statistical model, such as a neural network). As mentioned above, the radiation transfer model is also used in the color adjustment algorithm.

[0029] According to one embodiment of the proposed method, step f) comprises:

[0030] f1) Comparing the matching metric value for the adjusted preliminary matching formula with a first threshold value, wherein, if the matching metric value is less than or equal to the first threshold value, the adjusted preliminary matching formula is judged to be acceptable and no further improvement can be made with respect to pigmentation, otherwise continuing the matching and adjustment process of step g).

[0031] The threshold value is part of the configuration of the algorithm implemented on one or more processors.The first threshold value is typically in the range of 0.5...1.0.

[0032] According to another aspect, the proposed method further comprises the following steps:

[0033] l) sorting the list by using one or more processors with respect to the magnitude of the matching metric and optionally with respect to the number of redundant (and removed) pigments, respectively.

[0034] In another embodiment of the proposed method, the above step k) further comprises:

[0035] k1) comparing, for each adjusted modified preliminary formula (including the additional color base), the difference between the corresponding match metric value and the match metric value of the adjusted preliminary matching formula; and

[0036] k2) List only those additional coloring bases whose difference between the two matching metric values ​​is less than a second threshold (absolute improvement threshold) and whose assigned matching metric value is less than or equal to a determined ratio of the matching metric values ​​of the adjusted preliminary matching formula (relative improvement threshold).

[0037] The proposed method is based on a non-optimal starting formula, i.e., a non-optimal preliminary matching formula with respect to color and pigmentation, and sequentially tests additional coloring bases containing different types of pigments with respect to a decrease in a matching metric, which describes the color difference and spectral similarity between the relief curve of a target coating (target measurement) and one of the adjusted preliminary matching formulas, which is based on the pigmentation of a starting formula retrieved from a formula database. By sorting the results of each calculation by the improvement in the matching metric value and defining at least one threshold, the desired coloring base can be detected and displayed to generate a better starting formula with optimal pigmentation for further color matching.

[0038] According to a further embodiment of the proposed method, the adjusted modified preliminary matching formula associated with the at least one additional coloring base having the smallest assigned matching metric value is selected as the starting formula with the optimal coloring for further processing.

[0039] After determining the missing pigment and adding it to the recipe, the normal color adjustment process begins, which optimizes the matching metric consisting of at least color difference (e.g., dE*) and shape difference (dShape, dShape*). However, with the additional pigment, the adjustment converges better and the results are more robust and of better quality.

[0040] According to another embodiment of the proposed method, the method further comprises the following steps:

[0041] m) releasing at least one color base contained in the adjusted preliminary matching formula, in particular, said at least one color base being redundant due to the at least one additional color base and therefore to be reduced in quantity or to be completely excluded.

[0042] In some embodiments, the color base of the present invention is the color base of the color of the coating.Usually, the preliminary matching formula of adjustment comprises a plurality of different color bases, and every kind of color base is used as the base that generates specific light reflection / absorption characteristics on color.An example is green, and it can produce by the color base that comprises specific green pigment, or alternatively by the color base that comprises yellow pigment and the second color base that comprises blue pigment and mix and produce.Yet, for every kind of color, there is multiple color base to be considered when generating corresponding coating.Therefore, when searching for its outward appearance when being applied to the surface as coating, should be matched with the formula of target coating, there are a large amount of color bases that need to be considered.

[0043] According to yet another embodiment of the proposed method, the matching metric is selected as:

[0044]

[0045] Where n is an integer and k2 is a linear scaling factor, where for example k2=0.65, Calculated by the following formula:

[0046]

[0047] in

[0048]

[0049]

[0050] in, as well as

[0051] as well as

[0052] Δλ i =λ i+1 -λ i

[0053] in, Indicates the target coating at wavelength λ i The normalized reflectance value at Indicates the target coating at wavelength λ i+1 The normalized reflectance value at Indicates the sample coating at wavelength λ i The normalized reflectance value at Indicates the sample coating at wavelength λ i+1 The normalized reflectivity value at , k1 is the nonlinear damping parameter, where for example k1 = 0.005, and Indicates two normalized vectors and The angle between the vectors Indicates the target coating at λ iThe normalized gradient of the reflectivity curve at , and the vector Indicates sample coating at λ i The normalized gradient of the reflectivity curve at . Therefore, Indicates the wavelength value λ i A normalized difference / angle difference between the two spectral curves at .

[0054] According to another aspect of the proposed method, the matching metric is chosen as follows:

[0055]

[0056] in, is a linear scaling factor, where for example

[0057] Parameters k1 and k2, Can be freely selected to define together (see above formula) the matching measures dShape, dShape * scale.

[0058] Matching metrics dShape, dShape* produces values ​​in a scale (i.e., scale space) that is comparable to the scale space of the CIELab* color space and the scale space of color distance metrics defined in the CIELab* color space (such as, for example, the lightness difference metric dL* and the color difference metric dE*). As a result, most colorimetric data available and usable in color matching, adjustment, and search processes can be provided in a comparable scale, thereby facilitating the interpretation of colorimetric data in a holistic view.

[0059] For comparison purposes, the reflectance values ​​are normalized by a scaling function which is chosen to be a nonlinear scaling function f ref,smp , as follows:

[0060]

[0061] in

[0062]

[0063] in

[0064]

[0065] Among them, R ref, / smp,center Given by:

[0066]

[0067] in, and

[0068] in, express and Both, among them, is the target coating at wavelength λ i The reflectivity value at is the sample coating at wavelength λ i The reflectivity value at .

[0069] Nonlinear scaling function f ref,smp Refers to the lightness (L*) algorithm used to convert colors from the XYZ color space to the CIELab* color space. The L* metric is intended to simulate the logarithmic response of the human eye to lightness. The scaling function attempts to linearize the perceptibility of lightness. Due to the scaling function, the gain value of the matching metric can be interpreted regardless of the absolute color coordinates of the target coating, specifically its lightness L*.

[0070] Typically, the aim is to determine a formula whose color difference dE*, its spectral similarity measure dShape, and optionally its texture difference, its sparkle difference dS, and its granularity difference dG are minimized when all metrics are considered individually (i.e. alone). An alternative or complementary correction / modification of the optimal matching formula can be performed using a cost function that combines all those considered metrics, for example by adding together all the considered metrics: dE* (or dL*+da*+db*)+dShape(+dS+dG+....), and minimizing this cost function accordingly.

[0071] The present disclosure also relates to a system for providing a matching metric for matching and adjusting the pigmentation of a target coating, the system comprising:

[0072] A) Computing equipment;

[0073] B) A computer program product comprising computer executable code stored on a computer-readable storage medium functionally coupled to a computing device and causing the computing device to perform a computing process when run, the computing process comprising at least the following steps:

[0074] B1) retrieving a preliminary matching formula from a formula database comprising formulas for coating compositions having different pigmentation;

[0075] B2) providing a matching metric describing the color difference and spectral similarity between a given (e.g., measured) relief curve for the target coating and a relief curve determined for the preliminary matching formula;

[0076] B3) calculating a matching metric value for the preliminary matching formula based on the relief curve measured for the target coating and the relief curve determined for the preliminary matching formula;

[0077] B4) using a color adjustment algorithm to adjust the preliminary matching formula (the concentration of the included pigments) in a manner that minimizes the matching metric;

[0078] B5) evaluating the matching metric of the adjusted preliminary formula;

[0079] B6) judging whether the pigmentation of the adjusted preliminary matching formula can be significantly improved based on the magnitude of the matching metric value;

[0080] In cases where pigmentation can be significantly improved with the adjusted Primary Match formula:

[0081] B7) defining a selection of at least one additional tinting base that may be eligible for further adjustment to the adjusted primary matching formula of the target coating, each additional tinting base being associated with a corresponding modified primary matching formula consisting of the primary matching formula and the corresponding tinting base;

[0082] B8) calculating, for each of the at least one additional color base, a matching metric value for the corresponding modified preliminary matching formula;

[0083] B9) adjusting the modified preliminary matching formula with respect to the concentrations of the included pigments in a manner that minimizes the matching metric;

[0084] B10) assigning each of the at least one additional color base material to a corresponding one of the matching metric values ​​of the corresponding one of the adjusted modified preliminary matching formulas;

[0085] B11) publishing a list of at least those additional tinting bases of the at least one additional tinting base whose associated adjusted modified preliminary matching formula has a relief curve that is more similar to the relief curve of the target coating with respect to the matching metric than the relief curve of the adjusted preliminary matching formula.

[0086] According to one embodiment of the proposed system, the system further comprises:

[0087] C) Color measurement equipment;

[0088] D) a formulation database comprising formulas for coating compositions and interrelated colorimetric data;

[0089] The computing device is functionally coupled to the color measurement device and the recipe database. The computing device may further include an input device and a display device.

[0090] Typically, the color measurement device is a spectrometer, particularly a multi-angle spectrometer such as I or series of spectrometers.

[0091] According to one embodiment of the proposed system, the above step B6) comprises:

[0092] B6-1) Compare the matching metric value of the adjusted preliminary matching formula with a first threshold value, wherein, if the matching metric value is less than or equal to the first threshold value, the adjusted preliminary matching formula is judged to be acceptable, otherwise continue to perform the matching and adjustment process of step B7).

[0093] According to another aspect, the calculation process further comprises the following steps:

[0094] B12) Sort the list with respect to the magnitude of the matching metric and (optionally) with respect to the number of redundant (and removed) pigments.

[0095] According to another aspect, step B11) further comprises:

[0096] B11-1) comparing, for each adjusted modified preliminary formula (including the additional color base), the difference between the corresponding match metric value and the match metric value of the adjusted preliminary matching formula; and

[0097] B11-2) lists only those additional coloring bases whose difference between the two matching metric values ​​is less than a second threshold (absolute improvement threshold) and whose assigned matching metric value is less than or equal to a determined ratio of the matching metric values ​​of the adjusted preliminary matching formula (relative improvement threshold).

[0098] Typically, at least the color measurement device, the computing device, and the recipe database are networked with each other via corresponding communication connections. Each of the communication connections between the different components of the system can be a direct connection or an indirect connection. Each communication connection can be a wired or wireless connection. Any suitable communication technology can be used. The recipe database, the color measurement device, and the computing device can each include one or more communication interfaces for communicating with each other. Such communication can be performed using a wired data transmission protocol such as Fiber Distributed Data Interface (FDDI), Digital Subscriber Line (DSL), Ethernet, Asynchronous Transfer Mode (ATM), or any other wired transmission protocol. Alternatively, the communication can be performed wirelessly via a wireless communication network using any of a variety of protocols, such as General Packet Radio Service (GPRS), Universal Mobile Telecommunications System (UMTS), Code Division Multiple Access (CDMA), Long Term Evolution (LTE), Wireless Universal Serial Bus (USB), and / or any other wireless protocol. The corresponding communication can be a combination of wireless and wired communication.

[0099] The computing device may include or communicate with one or more input units, such as a touch screen, audio input, mobile input, mouse, keypad input, etc. In addition, the computing device may include or communicate with one or more output units, such as audio output, video output, screen / display output, etc.

[0100] Embodiments of the present invention can be used with or incorporated into a computer system, which can be a standalone unit or include one or more remote terminals or devices that communicate with a central computer located, for example, in the cloud, via a network (such as the Internet or an intranet). Thus, the computing devices and related components described herein can be part of a local computer system or a remote computer or online system, or a combination thereof. The recipe database and software described herein can be stored in a computer's internal memory or in a non-transitory computer-readable medium.

[0101] Within the scope of this disclosure, a database may be a part of a data storage unit or may represent the data storage unit itself.The terms "database" and "data storage unit" are used synonymously.

[0102] The proposed method and system allow for better integration of the color matching and adjustment processes. This allows for adequate color matching despite starting formulas with suboptimal pigmentation. Furthermore, the workload required for color development and customer service matching in the corresponding laboratory can be reduced. The overall color matching process is more reliable and faster.

[0103] The present disclosure also relates to a computer-readable storage medium functionally coupled to a computing device storing a computer program product, the computer program product including computer-executable code and causing the computing device to perform a computing process when executed, the computing process including at least the following steps:

[0104] B1) retrieving a preliminary matching formula from a formula database comprising formulas for coating compositions having different pigmentation;

[0105] B2) providing a matching metric describing the color difference and spectral similarity between a given (e.g., measured) relief curve for the target coating and a relief curve determined for the preliminary matching formula;

[0106] B3) calculating a matching metric value for the preliminary matching formula based on the relief curve measured for the target coating and the relief curve determined for the preliminary matching formula;

[0107] B4) using a color adjustment algorithm to adjust the preliminary matching formula (the concentration of the included pigments) in a manner that minimizes the matching metric;

[0108] B5) evaluating the matching metric of the adjusted preliminary formula;

[0109] B6) judging whether the pigmentation of the adjusted preliminary matching formula can be significantly improved based on the magnitude of the matching metric value;

[0110] In cases where pigmentation can be significantly improved with the adjusted Primary Match formula:

[0111] B7) defining a selection of at least one additional tinting base that may be eligible for further adjustment to the adjusted primary matching formula of the target coating, each additional tinting base being associated with a corresponding modified primary matching formula consisting of the primary matching formula and the corresponding tinting base;

[0112] B8) calculating a matching metric value of the corresponding modified preliminary matching formula for each of the at least one additional coloring base material;

[0113] B9) adjusting the modified preliminary matching formula with respect to the concentrations of the included pigments in a manner that minimizes the matching metric;

[0114] B10) assigning each of the at least one additional color base material to a corresponding one of the matching metric values ​​of the corresponding one of the adjusted modified preliminary matching formulas;

[0115] B11) publishing a list of at least those additional coloring bases of the at least one additional coloring base whose associated adjusted modified preliminary matching formula has a relief curve that is more similar to the relief curve of the target coating with respect to the matching metric than the relief curve of the adjusted preliminary matching formula.

[0116] According to one aspect of the proposed computer-readable storage medium, the computing process further comprises the following steps:

[0117] B12) Sort the list with respect to the magnitude of the matching metric and (optionally) with respect to the number of redundant (and removed) pigments.

[0118] The present invention is further defined in the following examples. It should be understood that these examples are given by way of illustration only, indicating preferred embodiments of the present invention. From the above discussion and examples, those skilled in the art will be able to ascertain the essential characteristics of the present invention and, without departing from the spirit and scope thereof, may make various changes and modifications to adapt the present invention to various uses and conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0119] Figure 1 Figure 1a The relief curve of the target coating and the relief curve with the preliminary matching formula for the non-optimal pigmentation of the target coating are shown in Figure 1b Further relief curves with a modified preliminary matching formula for optimal pigmentation of the target coating are also shown in .

[0120] Figure 2 A flow chart illustrating one embodiment of the proposed method is shown. DETAILED DESCRIPTION

[0121] Figure 1a A graph is shown having a horizontal axis 110 and a vertical axis 120, along which wavelength values ​​are plotted and along which reflectance values / intensities are plotted. Different relief curves are shown. Relief curves 101 and 111 are measured for a target coating at two different viewing angles (measurement geometries). Relief curves 102 and 112 are determined for the same preliminary matching formula at two different viewing angles. It can be clearly seen that the preliminary matching formula has non-optimal pigmentation with respect to the target coating, because for each considered viewing angle (measurement geometry), there is an unacceptable visible difference in shape between the relief curves 101, 111 of the target coating and the relief curves 102, 112 of the preliminary matching formula, respectively.

[0122] For Figure 1a The same perspective (measurement geometry) in Figure 1b In addition, relief curves 103, 113 of the modified preliminary matching formula are shown. Compared with the relief curves 102, 112 of the preliminary matching formula, these relief curves 103, 113 show a better similarity in shape to the target coating. This similarity can be calculated by means of a matching metric defined, for example, by formula (1) or (2) as described above. With the help of an embodiment of the proposed method, starting from the preliminary matching formula, an additional coloring base (i.e., an additional pigment to be added) can be found to improve the matching and added to the preliminary matching formula by systematically and continuously checking the spectral similarity and color difference of all available and suitable coloring bases added to the preliminary matching formula to produce the corresponding modified preliminary matching formula, thereby producing a corresponding modified preliminary matching formula of the target coating with a size based on the matching metric value calculated for each modified preliminary matching formula in this modified preliminary matching formula.

[0123] Figure 2 A flow chart showing one embodiment of the proposed method is shown. In step 201 a target coating is given (eg measured) which is to be matched by a color formula which has to be determined by a color matching process.

[0124] In method step 202, a starting formula (i.e., a preliminary matching formula) is retrieved from a recipe database containing formulas for coating compositions with different pigmentations. Typically, there are several primary colors, and for each primary color, there are several coloring bases, i.e., pigments. Each coating composition (and each formula for such a coating composition) is based on one or more coloring bases, which give the corresponding coating a specific appearance in terms of color, texture, etc. However, knowledge of color, texture, etc. alone cannot directly determine which coloring bases are used, as multiple coloring bases exist for each primary color.

[0125] The relief curve associated with the starting formula may also be retrieved from a database or predicted by a radiation transfer model. Alternatively, when a sample coating is provided based on the starting formula, the relief curve of the starting formula may be measured by a measuring device.

[0126] A relief curve for the target coating is given (eg, measured by a measuring device).

[0127] In step 203, matching metric f_m is provided, on this basis, how well the starting formula and the target coating are matched is assessed. In step 204, first by any formula correction method currently used in the color tool, optimize / adjust the starting formula, so that minimize matching metric f_m. This correction method (i.e., standard coloring method) can for example operate in color space and tool to improve the starting formula with respect to the concentration of all used tinting bases (colorants). For this task, a color adjustment algorithm based on a radiation transfer model (for example, a physical model like the Kubelka-Munk model (or a statistical model like a neural network)) is used. The color adjustment algorithm determines the concentration of the tinting base (or pigment) included in the preliminary matching formula, thereby draws optimal (minimum) matching metric.

[0128] From this correction method, an adjusted starting formula (formula adjustment) is generated. In step 205, the matching metric value f_m is evaluated according to the following inequality (condition):

[0129] f_m(Formula adj.)≥THRESHOLD1

[0130] f_m(Formula adj.) is the matching metric value of the adjusted starting formula. THRESHOLD1 is a predetermined parameter, also referred to as the first threshold value as described above.

[0131] Based on this inequality, ie, based on the size of the matching metric value f_m of the adjusted starting formula, it is judged that the pigmentation of the adjusted starting formula (ie, the adjusted preliminary matching formula) can be further significantly improved.

[0132] If f_m(Formula adj.) is less than the first threshold value THRESHOLD1, as indicated by arrow 206, no additional coloring base (i.e., no additional pigment) must be added to the adjusted starting formula in order to improve the match with the target coating (207). In step 208, it is indicated that the pigmentation of the starting formula appears to be OK. This statement is output to the user via an output device, for example, displayed on a display unit and / or output via an audio output device.

[0133] When f_m(Formula adj.) is greater than or equal to the first threshold THRESHOLD1, as shown by arrow 209, the purpose is to get closer to the pigmentation of the target coating by continuously adding available coloring base (i.e. pigment) to the adjusted starting formula (i.e. adjusted preliminary matching formula).

[0134] In step 210, a combined adjustment with n additional pigments is calculated, where n is a natural number. This means that successive additional coloring bases (i.e., one additional pigment #X after another) are selected from a set of n available coloring bases and added to the adjusted starting formula, each of which generates a modified preliminary matching formula. In the example described here, the set of available coloring bases includes n different coloring bases based on n different pigments, each pigment being designated #X. Each of these modified preliminary matching formulas has also been optimized / adjusted by any correction method as described with respect to step 204, resulting in an adjusted modified preliminary matching formula (Formula+pigm.#X adj.).

[0135] In step 211, the matching metric value of each adjusted modified preliminary matching formula, which is calculated based on the mitigation curve measured for the target coating and the mitigation curve determined for the corresponding adjusted modified preliminary matching formula, is evaluated according to the following inequality (condition):

[0136] f_m(Formula+pigm.#X adj.)≤c×f_m(Formula adj.)

[0137] as well as

[0138] f_m(Formula adj.)–f_m(Formula+pigm.#X adj.)>THRESHOLD2.

[0139] Here, c and THRESHOLD2 are pre-given parameters, for example, c=0.8 and THRESHOLD2=0.15, ..., 0.3.

[0140] If one or both of the inequalities are not satisfied, a statement is made in step 212 that the selected additional color base (i.e., additional pigment X) does not improve the match to the target coating, and therefore, the additional color base (i.e., the additional pigment) is skipped and does not need to be added to the adjusted starting formula to improve the match to the target coating. This statement is output to the user, for example, on a display unit and / or via an audio output device.

[0141] When both inequalities are satisfied, as shown by arrow 213, the corresponding pigment #X is saved in a list together with any change in the size of the corresponding matching metric value and the information about the pigment quantity used in the corresponding modified preliminary matching formula. Each modified preliminary matching formula "Formula+pigment#X adj." as previously mentioned has been adjusted using a color adjustment algorithm, which determines the concentration of all included coloring bases (or pigments) in the corresponding modified preliminary matching formula, thereby deriving an optional (minimum) matching metric. Therefore, the concentration of the coloring base will be set to zero. In this case, a coloring base is redundant, such as replaced by a newly added pigment #X, or is not needed.

[0142] These solutions may be preferred in order to provide a formulation with a small number of ingredients.

[0143] This process is repeated successively for all additional pigments #X(1,...,n).

[0144] In step 214, a resulting list of additional potential complementary pigments is obtained and sent via an output device.

[0145] Finally, in step 215, the list of potential additional pigments (i.e., additional coloring bases) is sorted based on the magnitude (i.e., minimum) of the matching metric value and (optionally) the number of redundant (and removed) pigments. The coloring base whose associated adjusted, modified preliminary matching formula has the smallest matching metric value (e.g., the lowest shape difference value and the lowest color distance dE*) is selected / selected as the coloring base, which is added to the adjusted starting formula to improve the match with the target coating. The selected coloring base is recommended to the user via a corresponding output unit (such as a display and / or audio output).

[0146] Alternatively, further consider how many pigments are included in the modified preliminary matching formula of the corresponding listed adjustment. Select the one with the lowest matching metric value and the least pigment quantity. If in doubt, the two conditions must be exchanged with each other.

[0147] This condition was evaluated for all color bases (ie, pigments listed).

[0148] Reference Symbols List

[0149] 110 horizontal axis

[0150] 120 vertical axis

[0151] 101 Relief curve for target coating

[0152] 111 Relief curve of target coating

[0153] 102 Preliminary matching relief curve

[0154] 112 Preliminary matching relief curve

[0155] 103 Relief curves for the modified preliminary matching formula

[0156] 113 Relief Curves for the Modified Preliminary Matching Formula

[0157] 201 Methods and Steps

[0158] 202 Methods and Steps

[0159] 203 Methods and Steps

[0160] 204 Methods and Steps

[0161] 205 Methods and Steps

[0162] 206 Arrow

[0163] 207 Conclusion

[0164] 208 Methods and Steps

[0165] 209 Arrow

[0166] 210 Methods and Steps

[0167] 211 Methods and Steps

[0168] 212 Methods and Steps

[0169] 213 Arrow

[0170] 214 Methods and Steps

[0171] 215 Methods and Steps

Claims

1. A computer-implemented method for matching and adjusting the pigmentation of a target coating, the method comprising at least the following steps: a) retrieving (202) a preliminary matching formula from a formula database comprising formulas for coating compositions having different pigmentations; b) providing (203) a matching metric describing the color difference and spectral similarity between a relief curve given for the target coating and a relief curve determined for the preliminary matching formula; as well as By using one or more processors: c) calculating (203) a matching metric value for the preliminary matching formula based on the relief curve given for the target coating and the relief curve determined for the preliminary matching formula; d) adjusting (204) the preliminary matching formula with respect to the included pigment concentrations in such a way that the matching metric is minimized; e) evaluating (205) the matching metric value of the adjusted preliminary matching formula; f) comparing the matching metric value for the adjusted preliminary matching formula with a first threshold (205), wherein if the matching metric value is less than or equal to the first threshold, the adjusted preliminary matching formula is judged to be acceptable, otherwise: g) successively adding available pigments to the adjusted preliminary matching formula to further adjust the adjusted preliminary matching formula to the target coating, each additional pigment being associated with a corresponding modified preliminary matching formula consisting of the adjusted pigmentation of the adjusted preliminary matching formula and a corresponding pigment; h) calculating, for each of the at least one additional pigment, a matching metric value for the corresponding modified preliminary matching formula; i) adjusting the modified preliminary matching formula with respect to the concentration of the included pigments in such a way that the matching metric value is minimized; j) assigning each of the at least one additional colorant to a respective one of the matching metric values ​​calculated for the respective adjusted modified preliminary matching formula; k) publishing (214) via an output device a list of at least those of the at least one additional pigment whose associated adjusted modified preliminary matching formulas respectively have relief curves that are more similar to the relief curve of the target coating than the relief curve of the adjusted preliminary matching formula with respect to the matching metric.

2. The method according to claim 1, further comprising the steps of: 1) Sort the lists according to the size of the matching metric values ​​(215).

3. The method according to claim 1, wherein Step k) further comprises: k1) for each adjusted modified preliminary matching formula, comparing (211) a difference between the corresponding matching metric value and the matching metric value of the adjusted preliminary matching formula; and k2) listing (213) only those additional pigments whose difference between two matching metric values ​​is less than a second threshold and whose assigned matching metric value is less than or equal to a determined ratio of said matching metric values ​​of said adjusted preliminary matching formula.

4. The method according to claim 2 or 3, wherein: The adjusted modified preliminary matching formula associated with the at least one additional pigment having the smallest assigned matching metric value is selected as the starting formula having the optimal pigmentation for further processing.

5. The method according to claim 1, further comprising the steps of: m) issuing at least one colorant contained in the adjusted preliminary matching formula, which is redundant and is therefore to be reduced in number or completely excluded.

6. The method according to claim 5, wherein: The at least one colorant is at least one additional colorant having a minimum assigned match metric value.

7. The method according to claim 1, wherein The matching metric is chosen to be: Where n is an integer and k2 is a linear scaling factor, Calculated by the following formula: in as well as as well as Dl i =λ i+1 -l i in, Indicates the target coating at wavelength value λ i The normalized reflectance value at Indicates the target coating at wavelength value λ i+1 The normalized reflectance value at Indicates that the sample coating is at the wavelength value λ i The normalized reflectance value at Indicates that the sample coating is at the wavelength value λ i+1 is the normalized reflectivity value at , k1 is the nonlinear damping parameter, and Indicates two normalized vectors and The angle between the vector Indicates the target coating at λ i The normalized gradient of the reflectivity curve at , and the vector Indicates that the sample coating is at λ i The normalized gradient of the reflectivity curve at .

8. The method according to claim 7, wherein: k2=0.65 and / or k1=0.

005.

9. The method according to claim 1, wherein The matching metric is chosen as follows: Where n is an integer, and is the linear scaling factor, as well as as well as Dl i =λ i+1 -l i , in, Indicates the target coating at wavelength value λ i The normalized reflectance value at Indicates the target coating at wavelength value λ i+1 The normalized reflectance value at Indicates that the sample coating is at the wavelength value λ i The normalized reflectance value at Indicates that the sample coating is at the wavelength value λ i+1 The normalized reflectivity value at , k1 is the nonlinear damping parameter.

10. The method according to claim 9, wherein: k1=0.005 and / or 11. The method according to any one of claims 7 to 10, wherein The reflectivity values ​​are normalized by a scaling function f which is chosen to be a non-linear scaling function: in in Among them, R ref / smp,center It is given by: in, and 12. A system for providing a matching metric for matching and adjusting the pigmentation of a target coating and at least one sample coating, the system comprising: A) Computing equipment; B) a computer program product comprising computer executable code stored on a computer readable storage medium functionally coupled to the computing device and causing the computing device to perform a computing process when run, the computing process comprising the steps of: B1) retrieving (202) a preliminary matching formula from a formula database comprising formulas for coating compositions having different pigmentation; B2) providing (203) a matching metric describing the color difference and spectral similarity between a relief curve given for the target coating and a relief curve determined for the preliminary matching formula; and By using one or more processors: B3) calculating (203) a matching metric value for the preliminary matching formula based on the relief curve given for the target coating and the relief curve determined for the preliminary matching formula; B4) adjusting (204) the preliminary matching formula with respect to the included pigment concentrations in such a way that the matching metric is minimized; B5) evaluating (205) the matching metric value of the adjusted preliminary matching formula; B6) comparing the matching metric value for the adjusted preliminary matching formula with a first threshold value (205), wherein if the matching metric value is less than or equal to the first threshold value, the adjusted preliminary matching formula is determined to be acceptable, otherwise: B7) successively adding available pigments to the adjusted preliminary matching formula to further adjust the adjusted preliminary matching formula to the target coating, each additional pigment being associated with a corresponding modified preliminary matching formula consisting of the adjusted pigmentation of the adjusted preliminary matching formula and the corresponding pigment; B8) calculating, for each of the at least one additional pigment, a matching metric value for the corresponding modified preliminary matching formula; B9) adjusting the modified preliminary matching formula with respect to the concentration of the included pigments in such a way that the matching metric value is minimized; B10) assigning each of the at least one additional pigment to a corresponding one of the matching metric values ​​calculated for the corresponding adjusted modified preliminary matching formula; B11) publishing (214) via an output device a list of at least those additional pigments of said at least one additional pigment whose associated adjusted modified preliminary matching formulas respectively have relief curves that are more similar to said relief curve of said target coating with respect to said matching metric than said relief curve of said adjusted preliminary matching formula.

13. The system of claim 12, further comprising: C) Color measurement equipment; D) the recipe database; Wherein, the computing device is functionally coupled to the color measurement device and the recipe database.

14. The system according to claim 12 or 13, wherein: The calculation process further comprises the following steps: B12) Sort the lists according to the sizes of the matching metric values ​​(215).

15. A computer-readable storage medium functionally coupled to a computing device storing a computer program product, the computer program product comprising computer-executable code and causing the computing device to perform a computing process when executed, the computing process comprising the steps of: B1) retrieving (202) a preliminary matching formula from a formula database comprising formulas for coating compositions having different pigmentation; B2) providing (203) a matching metric describing the color difference and spectral similarity between a relief curve given for the target coating and a relief curve determined for the preliminary matching formula; B3) calculating (203) a matching metric value for the preliminary matching formula based on the relief curve given for the target coating and the relief curve determined for the preliminary matching formula; B4) adjusting (204) the preliminary matching formula with respect to the included pigment concentrations in such a way that the matching metric is minimized; B5) evaluating (205) the matching metric value of the adjusted preliminary matching formula; B6) comparing the matching metric value for the adjusted preliminary matching formula with a first threshold value (205), wherein if the matching metric value is less than or equal to the first threshold value, the adjusted preliminary matching formula is determined to be acceptable, otherwise: B7) successively adding available pigments to the adjusted preliminary matching formula to further adjust the adjusted preliminary matching formula to the target coating, each additional pigment being associated with a corresponding modified preliminary matching formula consisting of the adjusted pigmentation of the adjusted preliminary matching formula and the corresponding pigment; B8) calculating a matching metric value of the corresponding modified preliminary matching formula for each of the at least one additional pigment; B9) adjusting the modified preliminary matching formula with respect to the concentration of the included pigments in such a way that the matching metric value is minimized; B10) assigning each of the at least one additional pigment to a corresponding one of the matching metric values ​​calculated for the corresponding adjusted modified preliminary matching formula; B11) publishing (214) via an output device a list of at least those additional pigments of said at least one additional pigment whose associated adjusted modified preliminary matching formulas respectively have relief curves that are more similar to said relief curve of said target coating with respect to said matching metric than said relief curve of said adjusted preliminary matching formula.

16. The computer-readable storage medium of claim 15, wherein: The calculation process further comprises the following steps: B12) Sort the lists according to the sizes of the matching metric values ​​(215).

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