TWI536002B - Methods and systems of comparison of colored materials - Google Patents

Description

Method and system for comparing colored materials

The present invention relates to the field of pigment detection technology, and more particularly to a method and system for comparing colored materials.

According to the transmittance spectrum or the reflection spectrum, the difference in color can be distinguished, but if the transmittance spectrum or the reflection spectrum of the same color is different, in addition to the concentration factor, it is also related to the composition of the pigment. How to solve the problem that the same pigment has different transmittance or reflectance spectra due to different concentrations, the conventional method is solved by Lambert-Beer law.

Lambert-Beer Law is a measure of the extent to which light absorbs light after it has penetrated an object. It generally refers to the relationship of the transmittance spectrum of the same pigment at a concentration ratio of n: T _A =(T _B ) ⁿ

The above formula indicates a transmittance which is known to be one, and another transmittance can be obtained even when the concentration ratio is also known. The aforementioned formula derived using Lambert-Beer's law can solve the problem of different spectra due to different concentrations of the same pigment.

If the reflectance spectrum is used instead of the transmittance spectrum. The reflectivity comparison formula derived by the conventional Lambert-Beer law is: R _A =(R _B ) ⁿ

However, the above formula is only applicable when using ideal measurements. In many applications, the spectrum of colored materials often fails to comply with the Lambert-Beer law formula for describing the concentration. The common reasons are: First, the surface of the colored material is not the Lambertian surface. ), that is, not the Perfect Diffuse Surface. When the surface of the colored material reflects more gloss, the correction is more. Second, the surface of the liquid container is uneven or defective. Furthermore, the pigment cannot be completely covered. Unevenness will also result.

For example, if a specific light (such as a light emitted by a halogen lamp) is irradiated with a sample of a colored substance (such as a magenta ink of a printer), and a sample of a colored substance having the same concentration and a different concentration of the sample to be tested, And using a spectrometer to measure the reflectance values of the colored materials in different wavelength bands in the preset wavelength band, the reflectance spectra of the sample of the colored substance and the standard sample in different bands can be obtained, as shown in Fig. 1, the sample to be tested is shown in Fig. 1. In the R _A line, the standard sample is shown in Figure 1 for the R _B line.

If the conventional Lambert-Beer law is used as the comparison formula, at this time, there will be two sections in the derived reflectance spectrum that cannot overlap: 450nm~600nm and 700nm~950nm, only one section is consistent, ie 400nm~450nm Therefore, it is difficult to discriminate that the sample to be tested of the colored substance is the same component as the standard sample, and the concentration ratio n will vary with the matching section.

The main object of the present invention is to provide a method and system for aligning colored materials, which can completely remove the interference caused by errors in spectral measurement, including gloss reflection, uneven pigment coating or imperfect surface of liquid container. The error can make the spectrum superimposed, and the 俾 can accurately identify whether the colored substance is the same component, and can be more accurately applied to the concentration judge.

In order to achieve the foregoing object, the present invention provides a method for comparing colored materials, comprising at least the following steps: a. irradiating a sample of a colored substance with a specific light, and measuring the colored substance at a preset Reflectance values of different wavelengths in the band to obtain a reflectance spectrum; b. Select a reflectance spectrum of a standard sample of a colored substance of a predetermined color and concentration; c. Compare the test sample with the standard sample according to the following comparison formula:

Wherein the reflectance calculation of R _'A line value, R _B based reflectance values colored material of the standard samples, n-concentration ratio, C ₁ is the correction factor;. D by spectra are overlapped, judges test sample and the standard to the receiving Whether the colored substances in the sample are of the same color.

In addition, the present invention further provides a non-destructive detection and alignment method for a colored substance, comprising at least the following steps: a. irradiating a sample of a colored substance with a specific light, and measuring the colored substance is different in a preset wavelength band. The reflectance value of the wavelength is obtained to obtain the reflectance spectrum; b. the reflectance spectrum of the standard sample of the colored substance of a predetermined color and concentration is selected; c. The sample to be tested and the standard sample are compared according to the following comparison formula: R' _A =(R _B xC ₂ ) ⁿ , where R' _A is the calculated reflectance value, R _B is the reflectance value of the standard sample colored substance, n is the concentration ratio, and C ₂ is the correction coefficient; d. Whether the colored substance of the sample and the standard sample is the same color.

In addition, the present invention further provides another method for comparing colored materials, comprising at least the following steps: a. irradiating a sample of a colored substance with a specific light, and measuring the reflection of the colored substance at a different wavelength in a predetermined wavelength band. Rate value to obtain a reflectance spectrum; b. select a reflectance spectrum of a standard sample of a colored substance of a predetermined color and concentration; c. compare the formula to the standard sample according to the following comparison formula:

Wherein the calculated reflectance R _'A line value, the reflectance of the standard sample R _B based colored substances, n for concentration ratio; D Analyzing the test sample by a colored substance with a standard sample of the same color if.

Furthermore, the present invention further provides a method for aligning a colored substance, comprising at least the following steps: a. irradiating a sample of a colored substance with a specific light, and measuring the colored substance at a different wavelength in a predetermined wavelength band. The reflectance value is obtained to obtain a reflectance spectrum; b. a reflectance spectrum of a standard sample of a colored substance of a predetermined color and concentration is selected; c. The sample to be tested and the standard sample are compared according to the following comparison formula:

Wherein, the R' _A is calculated as the reflectance value, R _B is the reflectance value of the standard sample of the colored substance, n is the concentration ratio, and f(λ) is the reflection of the substrate of the non-pure white of the sample under the wavelength λ Rate value; d. determine whether the colored substance of the sample to be tested and the standard sample are of the same color.

In addition, the present invention further provides another method for comparing colored substances, comprising at least the following steps: a. irradiating a sample of a colored substance with a specific light, and measuring the color of the colored substance in a predetermined wavelength band. The permeability value is obtained to obtain the transmittance spectrum; b. the transmittance spectrum of the standard sample of the colored substance of a predetermined color and concentration is selected; c. The sample to be tested and the standard sample are compared according to the following comparison formula:

Wherein, T 'of _A penetration value calculating system, T _B based the color material of the transmittance value of the standard sample, n is the concentration ratio, C ₁ is the correction factor; D Analyzing the measured sample colored with a standard sample of the subject. Whether the substance is the same color.

In addition, the present invention also provides another method for comparing colored materials, comprising at least the following steps: a. irradiating a sample of a colored substance with a specific light, and measuring the color of the colored substance in a predetermined wavelength band. The permeability value is obtained to obtain the transmittance spectrum; b. the transmittance spectrum of the standard sample of the colored substance of a predetermined color and concentration is selected; c. The sample to be tested and the standard sample are compared according to the following comparison formula:

Wherein, T 'of _A penetration value calculating system, T _B based the transmittance value of the standard sample of colored material, n is the concentration ratio, C ₂ is a correction coefficient; D Analyzing the measured sample colored with a standard sample of the subject. Whether the substance is the same color.

In addition, the present invention also provides another method for comparing colored materials, comprising at least the following steps: a. irradiating a sample of a colored substance with a specific light, and measuring the color of the colored substance in a predetermined wavelength band. The permeability value is obtained to obtain the transmittance spectrum; b. the transmittance spectrum of the standard sample of the colored substance of a predetermined color and concentration is selected; c. The sample to be tested and the standard sample are compared according to the following comparison formula:

Wherein, T 'of _A penetration value calculating system, T _B based the color material of the transmittance value of the standard sample, n is the concentration ratio; D Analyzing the test sample by a colored substance with a standard sample of the same color if.

10‧‧‧System

12‧‧‧Light source

14‧‧‧ Spectrometer

16‧‧‧Operating unit

22, 24‧‧‧ fiber

26‧‧‧ Computing Module

1‧‧‧Standard sample

Figure 1 shows the reflectance spectra of different samples of the sample and the standard sample of the colored substance using the conventional Lambert-Beer law as the comparison formula.

Figure 2 is a graph showing the reflectance spectrum of the method of the first preferred embodiment of the present invention.

Figure 3 is a graph showing the reflectance spectrum of the method of the second preferred embodiment of the present invention.

Figure 4 is a graph showing the reflectance spectrum of the method of the third preferred embodiment of the present invention.

Figure 5 is a graph showing the reflectance spectrum of the method of the fourth preferred embodiment of the present invention.

Figure 6 is a system diagram of a fourth preferred embodiment of the present invention.

Hereinafter, several preferred embodiments of the present invention will be further described in detail with reference to the drawings as follows:

First, in a preferred embodiment of the present invention, a method for comparing colored materials, the first step of which is to irradiate a sample of a colored substance with a specific light, and measure a reflectance value of the colored substance at a different wavelength in a predetermined wavelength band. To obtain a reflectance spectrum: the specific light may be the light emitted by the halogen lamp, and use a spectrometer to measure the reflectance spectrum of the colored substance of the sample under test in different wavelength bands (eg, 350 nm to 1000 nm), as shown in FIG. The substance is the magenta ink of the printer, and the sample to be tested is shown in the R _A line in Figure 2.

The second step of the present invention selects a reflectance spectrum of a standard sample of a colored substance of a predetermined color and concentration: selecting a standard sample of a colored substance having the same concentration and different concentrations as the sample component to be tested, and measuring a reflectance spectrum of the standard sample of the colored substance The standard sample of the colored substance is shown in the R _B line in Figure 2.

The third step of the present invention compares the tested sample to the standard sample according to the following comparison formula: or

Wherein the calculated reflectance R _'A line value, R _B based reflectance standard sample of the color material, n for concentration ratio, C _1, C ₂ is a correction coefficient.

The previous comparison formula is based on the reflectivity formula of Lambert-Beer's law. By multiplying the reflectance values of the respective standard samples by the correction coefficient C ₂ and calculating them, the reflectance values indicated by the broken lines in Fig. 2 can be obtained, where C ₂ = 1.15 and n = 0.63. As can be seen from Fig. 2, only one segment of the reflectance spectrum cannot be matched, that is, 450 nm to 600 nm.

The final step of the present invention determines whether the sample to be tested of the colored substance and the standard sample are of the same color: as shown in FIG. 2, the dotted line obtained by the operation of the correction formula is in the band 600~950nm and the gray solid line (R _A The line) is in agreement with each other. Therefore, it can be seen that the sample of the colored substance is the same color as the standard sample.

Therefore, the method for comparing the colored substances of the present invention can not only determine whether the sample to be tested of the colored substance and the standard sample are the same color, but also improve the problem that the wavelength of the higher reflectance cannot be matched in the comparison. .

Secondly, the present invention further provides a method for comparing colored materials according to another preferred embodiment, mainly for the correction that the colored substance cannot be completely covered, that is, when the pigment is applied to the surface of the object, the color can often be seen. There is a white part of the surface of the object (especially the dot matrix used in industrial printing). In order to avoid the reflection of white when the reflectance spectrum is measured, the white reflectance must be subtracted after the measurement. The steps are generally The foregoing embodiment is the same except that it compares the tested sample with the standard sample according to the following modified formula:

The correction formula is obtained by subtracting the correction coefficient C ₁ from the reflectance and scaling it according to the modified formula of the previous embodiment, wherein the R′ _A system calculates the reflectance value, and R _B is the standard sample. Reflectance value, n is the concentration ratio.

Therefore, according to the previous correction formula, the comparison correction can be performed, and the reconciliation can obtain the completely matched reflectance comparison data, that is, the different concentration spectra can be completely compared under the reflectance measurement, as shown in FIG. 3, wherein C ₁ = 0.0285, C ₂ = 1.148, n = 0.925.

Therefore, even if the colored substance does not completely cover the surface of the object (the pigment coating is uneven), the interference caused by the error in the spectral measurement can be completely removed by the above correction formula, and the reflection of the sample of the colored substance and the standard sample is completely obtained. The rate spectrum and the high degree of spectral superposition can accurately identify whether the colored substance is the same component, and can be more accurately applied to the determination of the concentration.

Secondly, the inventors further used the following experiments to measure the reflectance spectra of various concentrations of colored materials, and confirmed that the present invention can be applied to different concentrations of colored substances, as shown in the fourth and fifth figures:

First, different concentrations (25%, 50%, 75%, 100%, 200%, and 300%) of Cyan primary colors were printed on white A4 paper using a laser printer. The experiment was performed at C300 (concentration 300%). As a benchmark for comparison (dark solid line), use this reference spectrum to calculate (dashed line) to compare other concentration spectra, first use the conventional Lambert-Beer law for reflectivity comparison, and then use it before use. Correct the formula for comparison:

After the comparison, in order to know which part of the difference is mainly, the original spectrum and the comparison spectrum are subtracted, and the obtained data (x-line) can be used as a basis for which spectrum does not match. As shown in the fourth figure, the concentration comparison is performed using the conventional Lambert-Beer law. It can be found that the reflectance spectrum cannot be matched, and the effect of incompletely producing white parts by the pigment cover is most obvious. As shown in the fifth figure, using the correction ratio formula for concentration comparison, it can be found that all the concentrations can be matched, and the average difference of the comparison is less than 0.8%, which is very close to the measured spectral data.

Accordingly, the method of the present invention is indeed applicable to the comparison of colored substances of different concentrations, and the alignment results are in agreement.

In addition, as shown in FIG. 6, the present invention further provides a system 10 for implementing a method for comparing colored materials, comprising a light source 12, a spectrometer 14 and an operating unit 16. The light source 12 is a halogen lamp for generating light (through an optical fiber 22) for a sample of a colored substance to be tested and a standard sample 1. The spectrometer 14 is a conventional spectrometer for receiving a sample of a colored substance through another optical fiber 24. In contrast to the reflected light of the standard sample 1, the operating unit 16 is connected to the computer device of the spectrometer 14 and can present a spectrum of the sample of the colored substance to be tested and the standard sample 1, including a computing module 26, which is built in Lambert-Bill. The calculation software of the law of the reflectance correction law can calculate the reflectance value according to the comparison formula described in the previous embodiment to determine whether the colored substance of the sample to be tested and the standard sample 1 are of the same color.

It can be seen from the above that the method and system for aligning the colored substances of the present invention, through the measurement of the pigment spectrum, and the comparison operation by the modified Lambert-Beer law, can completely remove the gloss reflection and uneven pigment coating. The error caused by other factors makes the reflectance spectral alignment of the same colored substance accurately match, and can be applied to the detection of various colored substances or drugs, the classification and automatic comparison of the colored substance database, and the concentration. The judgment is of practical value.

Furthermore, when the object coated with the pigment (paper or canvas) has a non-pure white base, the alignment formula can be corrected to:

Wherein, the R' _A is calculated as the reflectance value, R _B is the reflectance value of the standard sample of the colored substance, n is the concentration ratio, and f(λ) is the reflection of the substrate of the non-pure white of the sample under the wavelength λ Rate value.

In addition, the method and system for comparing the colored substances of the present invention can determine whether the colored substance of the sample to be tested and the standard sample are of the same color by the transmittance, that is, the comparison formula in the method of the previous method can be changed to: or or

Wherein, T 'of _A penetration value calculating system, T _B based the transmittance value of the standard sample of colored material, n is the concentration ratio. In this way, it is also possible to obtain a high degree of superposition of the spectrum, which can accurately identify whether the colored substance is the same component, and determine the concentration and the like.

Claims (10)

A method for comparing colored materials includes at least the following steps: a. irradiating a sample of a colored substance with a specific light, and measuring a reflectance value of the colored substance at a different wavelength in a predetermined wavelength band, Obtaining a reflectance spectrum; b. selecting a reflectance spectrum of a standard sample of a colored substance of a predetermined color and concentration; c. comparing the test sample to the standard sample according to the following comparison formula: Wherein the calculating the R _'A line reflectivity values, R _B based the color material reflectance value of the standard sample of, n-concentration ratio, C ₁ is the correction factor; and d determining whether the subject colored substance test sample with a standard sample of. Whether it is the same color. A method for comparing colored materials includes at least the following steps: a. irradiating a sample of a colored substance with a specific light, and measuring a reflectance value of the colored substance at a different wavelength in a predetermined wavelength band, Obtaining a reflectance spectrum; b. selecting a reflectance spectrum of a standard sample of a colored substance of a predetermined color and concentration, c. comparing the test sample to the standard sample according to the following comparison formula: Wherein the calculating the R _'A line reflectivity values, R _B based the color material reflectance value of the standard sample of, n-concentration ratio, C ₂ is the correction factor; and d determining whether the subject colored substance test sample with a standard sample of. Whether it is the same color. A method for comparing colored materials includes at least the following steps: a. irradiating a sample of a colored substance with a specific light, and measuring a reflectance value of the colored substance at a different wavelength in a predetermined wavelength band, Obtaining a reflectance spectrum; b. selecting a reflectance spectrum of a standard sample of a colored substance of a predetermined color and concentration; c. comparing the test sample to the standard sample according to the following comparison formula: Wherein the reflectance calculation of R _'A line value, R _B line of the reflectance standard sample of colored material, n for concentration ratio, C _1, C ₂ is a correction coefficient; D Analyzing the measured sample with a standard sample of the subject. Whether the colored substances are the same color. A method for comparing colored materials includes at least the following steps: a. irradiating a sample of a colored substance with a specific light, and measuring a transmittance value of the colored substance at a different wavelength in a predetermined wavelength band to obtain a wearable value. Permeability spectrum; b. Select a transmittance spectrum of a standard sample of a colored substance of a predetermined color and concentration; c. Compare the sample to the standard sample according to the following comparison formula: Wherein, T 'of _A penetration value calculating system, T _B based the color material of the transmittance value of the standard sample, n is the concentration ratio, C ₁ is the correction factor; and d Analyzing the measured sample with a standard sample of the subject. Whether the colored substances are the same color. A method for comparing colored materials includes at least the following steps: a. irradiating a sample of a colored substance with a specific light, and measuring a transmittance value of the colored substance at a different wavelength in a predetermined wavelength band to obtain a wearable value. Permeability spectrum; b. Select a predetermined color and concentration of the color material standard of the transmittance spectrum; c. According to the following comparison formula to compare the sample to the standard sample: Wherein, T 'of _A penetration value calculating system, T _B based the color material of the transmittance value of the standard sample, n is the concentration ratio, C ₂ is the correction factor; and d Analyzing the measured sample with a standard sample of the subject. Whether the colored substances are the same color. A method for comparing colored materials includes at least the following steps: a. irradiating a sample of a colored substance with a specific light, and measuring a transmittance value of the colored substance at a different wavelength in a predetermined wavelength band to obtain a wearable value. Permeability spectrum; b. Select a transmittance spectrum of a standard sample of a colored substance of a predetermined color and concentration; c. Compare the sample to the standard sample according to the following comparison formula: Wherein, T 'of _A penetration value calculating system, T _B based the transmittance value of the standard sample of colored material, n is the concentration ratio, C _1, C ₂ is a correction coefficient;. D is determined by measuring the standard sample Whether the colored substances in the sample are of the same color. A method for comparing colored materials includes at least the following steps: a. irradiating a sample of a colored substance with a specific light, and measuring a reflectance value of the colored substance at a different wavelength in a predetermined wavelength band to obtain a reflectance Spectral; b. Select a reflectance spectrum of a standard sample of a colored substance of a predetermined color and concentration; c. Compare the test sample to the standard sample according to the following comparison formula: Wherein, the R' _A is calculated as the reflectance value, R _B is the reflectance value of the standard sample of the colored substance, n is the concentration ratio, and f(λ) is the reflection of the substrate of the non-pure white of the sample under the wavelength λ The rate value, C ₁ and C ₂ are correction coefficients; d. determining whether the colored substance of the sample to be tested and the standard sample are of the same color. The method for comparing colored materials according to the first, second, third, fourth, fifth, sixth or seventh aspect of the patent application, wherein in step c, the comparison formula is the reflectance or penetration of Lambert-Beer law. Rate correction formula. A system for carrying out the method of claim 1, 2, 3, 4, 5, 6, 7, or 8 of the patent application, comprising: a light source for generating a light-irradiated colored substance test sample and a standard sample; a spectrometer that receives reflected or transmitted light from a sample of a colored substance and a standard sample through an optical fiber; and an operating unit that is coupled to the spectrometer and includes a computing module that exhibits a spectrum of the sample to be tested and the standard sample of the colored substance The graph and the calculation of the reflectance value or the transmittance value according to a comparison formula are used to determine whether the colored substance of the sample to be tested and the standard sample are of the same color. The system of claim 9, wherein the light source is a halogen lamp.