Method for calculating optical depth and albedo based on plastic product

Abstract

The invention discloses a method for calculating optical depth and albedo based on a plastic product, which comprises the following steps of: S1, placing a sample under black and white substrates, measuring the reflectivity R < white > and R < black > under the white and black substrates through a color photometer, and calculating a difference value delta R; s2, according to set environmental parameters, constructing a light path analysis model of the sample in the environment, and obtaining the radiation intensity of each light path; the method comprises the following steps of S1, measuring parameters of a sample under the set environment parameters, S2, calculating the reflectivity, the primary transmittance and the secondary transmittance according to the parameters measured in the step S2, and calculating the optical depth at the same time, and S4, calculating the albedo of the sample under the set environment parameters according to the optical depth obtained in the step S3. The set environmental parameters and reflectivity are used for calculating the optical depth and albedo, two new indexes during color matching of the plastic product are provided, and meanwhile reliable characteristic parameters are provided for deep learning of a neural network.

Description

Technical Field

[0001] The invention relates to the field of optical detection, and in particular to a calculation method based on optical depth and albedo of plastic products. Background Art

[0002] Optical depth refers to the measure of the opacity of the material layer, that is, the measure of the ability of the medium to absorb radiation is equal to the ratio of the incident radiation intensity to the outgoing radiation intensity; while albedo refers to the ratio of the light flux φ scattered in all directions by the entire illuminated part of the celestial surface to the light flux φ0 incident on the surface of the celestial body. It is the total reflected radiation to the incident radiation, so it includes diffuse reflection and specular reflection.

[0003] In the field of color matching of plastic products, in order to align the actual color effect of the product with the effect of the color matching system, it is often necessary to study the optical properties of plastic products. Generally, the two main characteristic parameters of reflectivity and transmittance are mostly used to define the optical properties of plastic products. However, with the increasing number of application scenarios of plastic products, the types of plastic materials are becoming more and more abundant, and many of them are even transparent or translucent. This makes the optical properties of plastics more complex, which puts higher requirements on the accuracy of color matching. In order to improve the color matching effect, it is necessary to introduce more characteristic parameters to more accurately define the optical characteristics of plastic products, which is convenient for subsequent color adjustment or as characteristic parameters of deep learning models.

[0004] To this end, this solution applies the concepts of optical depth and albedo to plastic products, thereby improving the accuracy of the color matching system or deep learning model. Summary of the invention

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a method for calculating the optical depth and albedo of a plastic product, comprising the following steps: Step S1: Place the sample under a black substrate and a white substrate, and measure the reflectivity R under the white substrate using a colorimeter 白 And the reflectivity R under the black substrate 黑 , and calculate R 黑 and R 白 The difference ΔR; Step S2: constructing an optical path analysis model of the sample in the environment according to the set environmental parameters and reflection conditions, and obtaining the radiation intensity of each optical path under the optical model; Step S3: Calculate the reflectivity, primary transmittance and secondary transmittance respectively by using the parameters measured in step S2, and calculate the optical depth by combining the ΔR obtained in step S1. The specific formula is as follows: Tau=

[0006] Wherein, Tau is the optical depth, A0 is the radiation intensity of the incident light, A2 is the radiation intensity of the once transmitted light, and A4 is the radiation intensity of the incident light after scattering and then transmitted; Step S4: Calculate the single scattering albedo of the sample under the set environmental parameters according to the optical depth obtained in step S3. The specific formula is as follows:

[0007] Among them, Ω is albedo, r is reflectivity, A1 is the radiation intensity of the first reflected light, A0 is the radiation intensity of the incident light, R 白 is the reflectivity of the sample under the white substrate, and T is the transmittance.

[0008] The environmental parameters and reflection conditions set in step 2 include: Setting 1: The scattered light generated by the sample is uniform, with the same intensity distribution in any direction; Setting 2: After the incident light is transmitted twice and scattered twice, the radiation intensity decays to 0.

[0009] The optical model in step S2 includes: a light path model of incident light irradiating the sample, a light path model of transmitted light irradiating the black and white substrate, and a light path model of the incident light after secondary transmission.

[0010] The radiation intensity of each light path in step S2 includes: The radiation intensity of incident light is A0, the radiation intensity of once reflected light is A1, the radiation intensity of once transmitted light is A2, the radiation intensity of light reflected after scattering A3, the radiation intensity of light transmitted after scattering A4, the radiation intensity of light reflected by the substrate A5, the radiation intensity of light reflected by the substrate on the sample surface A6, the radiation intensity of light refracted after entering the sample after being reflected by the substrate A7, the radiation intensity of light refracted after entering the sample after being reflected by the substrate A8, and the radiation intensity of light refracted after entering the sample after being refracted back to the substrate A9.

[0011] The formula for calculating the reflectivity in step S3 is as follows:

[0012] The formula for calculating the primary transmittance in step S3 is as follows: T1=

[0013] The formula for calculating the secondary transmittance in step S3 is as follows: T2=

[0014] Wherein, r in step S4 can be calculated by the following formula:

[0015]

[0016]

[0017] When the sample is made of a transparent material, the reflectivity R0 of the sample is regarded as A1 / A0, and then:

[0018] The implementation of the embodiments of the present invention has the following beneficial effects: ① This solution introduces the concepts of optical depth and albedo into the study of the optical properties of plastic products. Compared with the traditional solution that only defines the optical properties of plastic products by scattering coefficient and reflection coefficient, it provides more characteristic parameters for subsequent color matching or deep learning of neural network models, thereby making color matching and deep learning more accurate. ② This solution uses an optical path analysis model, and at the same time uses the reflectivity in the two cases of black padding and white padding, as well as the primary transmittance and secondary transmittance obtained by intermediate calculation, combined with the omission of some variables with minimal influence under the set environmental parameters, so that the optical depth and albedo that cannot be measured can be obtained by calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the present invention; Figure 2 (A) is the optical path model of the incident light irradiating the sample, (B) is the optical path model of the transmitted light irradiating the black and white substrate, and (C) is the optical path model of the incident light after secondary transmission and scattering; Figure 3 It is a schematic diagram of the optical path analysis model of the present invention. DETAILED DESCRIPTION

[0020] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0021] Example 1 This embodiment mainly discloses a calculation method based on the optical depth and albedo of plastic products. It uses the concepts of optical depth and albedo as new feature parameters for color matching of plastic products, thereby improving the accuracy of plastic products in color matching and partially using neural network deep learning for color matching prediction.

[0022] At the same time, this scheme ignores the possible uneven transmission and scattering of the sample and the high-order scattered and transmitted light by setting the environmental parameters and reflection conditions, and uses optical measuring instruments and intermediate light path analysis models to analyze the mathematical relationship between optical depth and albedo, so that the optical depth and albedo can be directly calculated. Specifically, the following steps are included: Step S1: Place the sample under a black substrate and a white substrate, and measure the reflectivity R under the white substrate using a colorimeter 白 And the reflectivity R under the black substrate 黑 , and calculate R 黑 and R 白 The difference ΔR; Step S2: constructing an optical path analysis model of the sample in the environment according to the set environmental parameters and reflection conditions, and obtaining the radiation intensity of each optical path under the optical model; Step S3: Calculate the reflectivity, primary transmittance and secondary transmittance respectively by using the parameters measured in step S2, and calculate the optical depth by combining the ΔR obtained in step S1. The specific formula is as follows: Tau=

[0023] Wherein, Tau is the optical depth, A0 is the radiation intensity of the incident light, A2 is the radiation intensity of the once transmitted light, and A4 is the radiation intensity of the transmitted light after the incident light is scattered; Step S4: Calculate the single scattering albedo of the sample under the set environmental parameters according to the optical depth obtained in step S3. The specific formula is as follows:

[0024] Among them, Ω is albedo, r is reflectivity, A1 is the radiation intensity of the first reflected light, A0 is the radiation intensity of the incident light, R 白 is the reflectivity of the sample under the white substrate, and T is the transmittance.

[0025] Specifically, the environmental parameters and reflection conditions set in step 2 include: Setting 1: the scattered light generated by the plastic is uniform, and the intensity distribution is the same in any direction; Setting 2: after the incident light is transmitted twice and scattered twice, the radiation intensity decays to 0.

[0026] The above setting 1 is used to ignore part of the uneven scattered light caused by the sample material, and the above setting 2 is used to ignore the high-order transmitted and scattered light, thereby making it possible to calculate the optical depth and albedo. In actual situations, the high-order transmitted and scattered light has decayed to a minimum value after two transmissions and scatterings, and has little effect on the overall result.

[0027] Example 2 This embodiment mainly discloses the process of the optical path analysis model in step S2. Figure 2 The entire optical path analysis model is specifically divided into three stages: the optical path model of the incident light irradiating the sample, the optical path model of the transmitted light irradiating the black and white substrate, and the optical path model of the incident light after secondary transmission.

[0028] like Figure 2 As shown in (A), when the incident light with a light radiation intensity of A0 is irradiated on the sample, its light path in the sample is divided into four parts: one reflection occurs on the surface of the sample, and the light radiation intensity of the one reflection is recorded as A1; one part directly passes through the sample, and its light radiation intensity is recorded as A2; one part is scattered inside the sample and reflected out of the sample, and its light radiation intensity is recorded as A3; at the same time, a part of the light scattered inside the sample is directly transmitted out of the sample without reflection, and its light radiation intensity is recorded as A4.

[0029] like Figure 2 As shown in (B), when the incident light passes through the surface of the sample, the light transmitted to the substrate includes: the light path directly transmitted out of the sample, that is, the part with light radiation intensity A2, and the light path of the incident light scattered inside the sample and then transmitted out of the sample, that is, the part with light radiation intensity recorded as A4.

[0030] When these two parts of the light path are irradiated on the black or white substrate, reflection will occur, and the light radiation intensity of the reflected light is recorded as A5.

[0031] like Figure 2 As shown in (C), when the reflected light from the substrate, which is the light path denoted as A5, is directed toward the sample, a part of it will be directly reflected, and its light radiation intensity is denoted as A6; a part of the reflected light from the substrate enters the interior of the sample and is refracted before directly passing through the sample, and its light radiation intensity is denoted as A7; at the same time, a part of the reflected light from the substrate will also be scattered inside the sample, including the light path that is reflected inside the sample after scattering, and its light radiation intensity is denoted as A8; another part of it will directly pass through the sample, and its light radiation intensity is denoted as A9.

[0032] Example 3 Based on Example 1 and Example 2, this example uses the reflectivity of the sample under a standard black and white substrate and the reflectivity of the sample itself under a black and white substrate, which are easily measured in engineering, and their difference, to calculate the optical depth and albedo of different pigments through optical path analysis and on the basis of reasonable assumptions.

[0033] First, based on the optical path analysis model of Example 2, the reflectivity R, the primary transmittance and the secondary transmittance are calculated. Specifically, the calculation formula of the reflectivity R is as follows:

[0034] The calculation formula of the primary transmittance is as follows: T1=

[0035] The calculation formula of the secondary transmittance is as follows: T2=

[0036] Combined with the reflectivity R under the black and white pads 白 , R 黑 , and the difference Δr between the two, then: A2+A4=

[0037] Since the optical depth is equal to the ratio of the incident radiation intensity to the outgoing radiation intensity, and the transmittance T is equal to the ratio of the transmitted luminous flux to the incident luminous flux, it can be seen that the two are reciprocals of each other, so the optical depth is calculated from the transmittance, that is: Tau=

[0038] According to the reflectivity data, we can get: Tau=

[0039] like Figure 3 As shown, albedo represents the relative attenuation due to scattering only on the surface or within the volume. Therefore, albedo is a measure of diffuse reflection of the medium. Specifically, the following mathematical relationship exists between the light radiation intensity, reflectivity and albedo of each light path:

[0040]

[0041]

[0042] Then it can be deduced that:

[0043] Among them, albedo is Ω, r is reflectivity, A1 is the radiation intensity of the first reflected light, A0 is the radiation intensity of the incident light, R 白 is the reflectivity of the sample under the white substrate, and T is the transmittance.

[0044] In addition, when the sample is made of transparent material, the reflectivity R0 of the sample is regarded as A1 / A0, and then:

[0045] Of course, the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any modifications made according to the spirit of the main technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for calculating the optical depth and albedo of plastic products, characterized in that: The following steps are involved: Step S1: Place the sample under a black substrate and a white substrate, and measure the reflectivity R under the white substrate using a colorimeter 白 And the reflectivity R under the black substrate 黑 , and calculate R 黑 and R 白 The difference ΔR; Step S2: constructing an optical path analysis model of the sample in the environment according to the set environmental parameters and reflection conditions, and obtaining the radiation intensity of each optical path under the optical model; Step S3: Calculate the reflectivity, primary transmittance and secondary transmittance respectively by using the parameters measured in step S2, and calculate the optical depth by combining the ΔR obtained in step S1. The specific formula is as follows: Got it= Wherein, Tau is the optical depth, A0 is the radiation intensity of the incident light, A2 is the radiation intensity of the once transmitted light, and A4 is the radiation intensity of the transmitted light after the incident light is scattered; Step S4: Calculate the albedo of the sample under the set environmental parameters according to the optical depth obtained in step S3. The specific formula is as follows: Among them, Ω is albedo, r is reflectivity, A1 is the radiation intensity of the first reflected light, A0 is the radiation intensity of the incident light, R 白 is the reflectivity of the sample under the white substrate, and T is the transmittance.

2. A method for calculating optical depth and albedo of plastic products according to claim 1, characterized in that: The environmental parameters and reflection conditions set in step 2 include: Setting 1: The scattered light generated by the sample is uniform, with the same intensity distribution in any direction; Setting 2: After the incident light is transmitted twice and scattered twice, the radiation intensity decays to 0.

3. The method for calculating the optical depth and albedo of plastic products according to claim 1, characterized in that: The optical model in step S2 includes: a light path model of incident light irradiating the sample, a light path model of transmitted light irradiating the black and white substrate, and a light path model of the incident light after secondary transmission.

4. The method for calculating the optical depth and albedo of plastic products according to claim 1, characterized in that: The radiation intensity of each light path in step S2 includes: The radiation intensity of incident light is A0, the radiation intensity of once reflected light is A1, the radiation intensity of once transmitted light is A2, the radiation intensity of the light reflected after the incident light is scattered is A3, and the radiation intensity of the light transmitted after the incident light is scattered is A4; The radiation intensity of the incident light after being reflected by the substrate is A5, the radiation intensity of the light reflected by the substrate and then reflected on the sample surface is A6, the radiation intensity of the transmitted light after the light reflected by the substrate enters the sample is A7, the radiation intensity of the transmitted light after the light reflected by the substrate enters the sample and is refracted back to the substrate is A8, and the radiation intensity of the refracted light after the light reflected by the substrate enters the sample and is refracted twice is A9.

5. The method for calculating the optical depth and albedo of plastic products according to claim 1, characterized in that: The formula for calculating the reflectivity in step S3 is as follows: 。 6. The method for calculating optical depth and albedo of plastic products according to claim 1, characterized in that: The formula for calculating the primary transmittance in step S3 is as follows: T1= 。 7. The method for calculating optical depth and albedo of plastic products according to claim 1, characterized in that: The formula for calculating the secondary transmittance in step S3 is as follows: T2= 。 8. The method for calculating optical depth and albedo of plastic products according to claim 1, characterized in that: The r in step S4 can be calculated by the following formula: 。 9. The method for calculating optical depth and albedo of plastic products according to claim 1, characterized in that: When the sample is made of transparent material, the reflectivity R0 of the sample is regarded as A1 / A0, then: 。

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