A calculation method based on the optical depth and albedo of plastic products

Abstract

The present invention discloses a calculation method for the optical depth and albedo based on plastic products, comprising the following steps: Step S1: Place the specimen under black and white substrates, and measure the reflectances R 白 , R 黑 under the white and black substrates by a colorimeter, and calculate the difference ΔR; Step S2: Construct an optical path analysis model of the specimen under the set environmental parameters to obtain the radiation intensity of each optical path; Step S3: Calculate the reflectance, the primary transmittance and the secondary transmittance respectively through the parameters measured in Step S2, and calculate the optical depth at the same time. Step S4: Calculate the albedo of the specimen under the set environmental parameters according to the optical depth obtained in Step S3. The present invention applies the optical depth and albedo to the color matching of plastic products, and calculates the optical depth and albedo by using the set environmental parameters and the reflectance. The present invention provides two new indexes for the color matching of plastic products, and provides reliable characteristic parameters for the deep learning of neural networks at the same time.

Description

Technical Field

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

[0002] Optical depth refers to a measure of the opacity of a material layer, that is, a measure of the ability of a medium to absorb radiation, which 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 fully illuminated part of the celestial body surface to the light flux φ incident on the celestial body surface. It is the ratio of all reflected radiation to incident radiation, so it includes diffuse reflection and specular reflection. 0 The ratio is of all reflected radiation to 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, its optical properties are defined by two main characteristic parameters, namely reflectivity and transmittance. However, as the application scenarios of plastic products are increasing, the types of plastic materials are also becoming more diverse, and many of them are even transparent or semi-transparent materials. This makes the optical properties of plastics more complex, which requires higher accuracy in color matching. In order to improve the color matching effect, more characteristic parameters need to be introduced to more accurately define the optical characteristics of plastic products, so as to facilitate subsequent color adjustment or as characteristic parameters of a deep learning model.

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

[0005] To solve the above technical problems, an embodiment of the present invention provides a method for calculating the optical depth and albedo based on plastic products, including the following steps:

[0006] Step S1: Place the specimen under a black substrate and a white substrate, and measure the reflectivity R under the white substrate 白 and the reflectivity R under the black substrate 黑 , and calculate the difference ΔR between R 黑 and R 白 .

[0007] Step S2: According to the set environmental parameters and reflection conditions, construct an optical path analysis model of the specimen in this environment, and obtain the radiation intensity of each optical path in this optical model.

[0008] Step S3: Calculate the reflectivity, the first transmittance, and the second transmittance respectively based on the parameters measured in Step S2. At the same time, calculate the optical depth by combining ΔR obtained in Step S1. The specific formulas are as follows:

[0009] Tau =

[0010] where Tau is the optical depth, A 0 is the incident light radiation intensity, A 2 is the first transmitted light radiation intensity, A 4 is the radiation intensity of the incident light after scattering and then transmission;

[0011] 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:

[0012]

[0013] where Ω is the albedo, R is the reflectivity, A 1 is the first reflected light radiation intensity A 1 , A 0 is the incident light radiation intensity, R 白 is the reflectivity of the sample on the white substrate, and T is the transmittance.

[0014] Among them, the environmental parameters and reflection conditions set in Step 2 include:

[0015] Setting 1: The scattered light generated by the sample is uniform, and the intensity distribution is the same in any direction;

[0016] Setting 2: After the incident light undergoes two transmissions and two scatterings, the radiation intensity decays to 0.

[0017] Among them, the optical model in Step S2 includes: 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 two transmissions.

[0018] Among them, the radiation intensities of each optical path in Step S2 include:

[0019] Incident light radiation intensity A 0 , First reflected light radiation intensity A 1 , First transmitted light radiation intensity A 2 , Radiation intensity of the incident light after scattering and then reflection A 3 , Radiation intensity of the incident light after scattering and then transmission A 4 , Light radiation intensity of the incident light after reflection by the substrate A 5 , Radiation intensity of the light reflected by the substrate and then reflected again on the surface of the sample A 6, the radiation intensity A of the refracted light after the basal reflected light enters the sample 7 , the light radiation intensity A of the refracted light that is refracted back into the substrate after the basal reflected light enters the sample 8 , the radiation intensity A of the refracted light after the basal reflected light enters the sample and undergoes double refraction 9 .

[0020] Among them, the formula for calculating the reflectivity in step S3 is as follows:

[0021]

[0022] Among them, the formula for calculating the single transmittance in step S3 is as follows:

[0023] T 1 =

[0024] Among them, the formula for calculating the double transmittance in step S3 is as follows:

[0025] T 2 =

[0026] Among them, r in step S4 can be obtained by the following formula:

[0027]

[0028]

[0029]

[0030] Among them, when the sample is made of a transparent material, the reflectivity R of the sample 0 is regarded as A 1 / A 0 , then there is:

[0031]

[0032] Implementing 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 through the 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 through the reflectivities in the cases of black padding and white padding, as well as the single transmittance and double transmittance obtained through intermediate calculations, and by omitting some variables with extremely small influences under the set environmental parameters, the optical depth and albedo that cannot be measured can be obtained through calculation. Description of the Drawings

[0033] Figure 1 is a schematic diagram of the present invention;

[0034] Figure 2 (A) is the optical path model of incident light irradiating the sample, (B) is the optical path model of transmitted light irradiating on the black and white substrates, and (C) is the optical path model of incident light after secondary transmission and scattering;

[0035] Figure 3 is a schematic diagram of the optical path analysis model of the present invention. Detailed implementation manners

[0036] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0037] Example 1

[0038] This example mainly discloses a calculation method for the optical depth and albedo of plastic products. Aiming at the color matching of plastic products, the two concepts of optical depth and albedo are used as new characteristic parameters, thereby improving the accuracy of plastic products in color matching and in the part of color matching prediction using neural network deep learning.

[0039] At the same time, through the set environmental parameters and reflection conditions, this solution ignores the possible uneven transmission and scattering conditions of the sample, as well as the high-order scattering and transmitted light, and uses an optical measuring instrument and an intermediate optical path analysis model to analyze the mathematical relationship between the optical depth and the albedo, so that the optical depth and the albedo can be directly calculated. Specifically, it includes the following steps:

[0040] Step S1: Place the sample under the black substrate and the white substrate, and measure the reflectance R under the white substrate 白 and the reflectance R under the black substrate 黑 , and calculate the difference ΔR between R 黑 and R 白 ;

[0041] Step S2: According to the set environmental parameters and reflection conditions, construct an optical path analysis model of the sample in this environment, and obtain the radiation intensity of each optical path in this optical model;

[0042] Step S3: Through the parameters measured in Step S2, calculate the reflectance, the first transmission rate and the second transmission rate respectively, and at the same time calculate the optical depth in combination with ΔR obtained in Step S1. The specific calculation formula is as follows:

[0043] Tau =

[0044] where Tau is the optical depth, A 0 is the radiation intensity of the incident light, A2 is the intensity of the primary transmitted light radiation, A 4 is the intensity of the radiation of the light that is transmitted after being scattered by the incident light;

[0045] Step S4: Calculate the single-scattering albedo of the specimen under the set environmental parameters according to the optical depth obtained in Step S3. The specific calculation formula is as follows:

[0046]

[0047] where Ω is the albedo, R is the reflectivity, and A 1 is the intensity of the primary reflected light radiation A 1 and A 0 is the intensity of the incident light radiation, R 白 is the reflectivity of the specimen on the white substrate, and T is the transmittance.

[0048] 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 passes through two transmissions and two scatterings, the radiation intensity is attenuated to 0.

[0049] The above Setting 1 is used to ignore part of the non-uniform scattered light caused by the specimen 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 been attenuated to a very small value after two transmissions and two scatterings, and has a very small impact on the overall result.

[0050] Example 2

[0051] This example mainly discloses the process of the optical path analysis model in Step S2. Specifically, please refer to Figure 2 , and the entire optical path analysis model is specifically divided into three stages: the optical path model of the incident light irradiating the specimen, the optical path model of the transmitted light irradiating the black and white substrate, and the optical path model of the incident light after two transmissions.

[0052] As Figure 2 (A) shows, when the incident light with the light radiation intensity of A 0 irradiates the specimen, its optical path in the specimen is divided into four parts in total: a primary reflection occurs on the surface of the specimen, and the light radiation intensity of the primary reflection is denoted as A 1 ; a part directly passes through the specimen, and its light radiation intensity is denoted as A 2 ; a part is scattered inside the specimen and reflected out of the specimen, and its light radiation intensity is denoted as A 3 , and at the same time, there is also a part of the light scattered inside the specimen that directly passes out of the specimen without reflection, and its light radiation intensity is denoted as A 4 .

[0053] As Figure 2 shown in (B), when the incident light passes through the surface of the sample, the light transmitted to the substrate includes: the optical path directly transmitted out of the sample, that is, the part with a light radiation intensity of A 2 and the optical path of the incident light scattered inside the sample and then transmitted out of the sample, that is, the part with a light radiation intensity denoted as A 4 .

[0054] When these two parts of the optical path irradiate on the black or white substrate, reflection will occur, and the light radiation intensity of the reflected light is denoted as A 5 .

[0055] As Figure 2 shown in (C), when the reflected light of the substrate, that is, the optical path denoted as A 5 shoots towards the sample, a part of it will directly reflect, and the light radiation intensity is denoted as A 6 ; a part of the reflected light of the substrate enters the sample and is directly transmitted through the sample after refraction, and the light radiation intensity is denoted as A 7 ; at the same time, a part of the reflected light of the substrate will also scatter inside the sample, which includes the optical path of reflection that occurs again inside the sample after scattering, and the light radiation intensity is denoted as A 8 , and another part is directly transmitted through the sample, and the light radiation intensity is denoted as A 9 .

[0056] Example 3

[0057] Based on Example 1 and Example 2, this example uses the reflectivity of the sample under standard black and white substrates, the self - reflectivity of the black and white substrates and their differences that are easily measured in engineering. Through optical path analysis and on the basis of reasonable assumptions, the optical depth and albedo of different pigments are calculated.

[0058] 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:

[0059]

[0060] The calculation formula of the primary transmittance is as follows:

[0061] T 1 =

[0062] The calculation formula of the secondary transmittance is as follows:

[0063] T 2 =

[0064] Reflectance R under the black and white substrates of the bonding pad 白 、R 黑 , and the difference Δr between the two, then there is:

[0065] A 2 +A 4 =

[0066] 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 light flux to the incident light flux, it can be seen that the two are reciprocals of each other. Therefore, the optical depth is calculated from the transmittance, that is:

[0067] Tau=

[0068] According to the reflectance data, it can be obtained that:

[0069] Tau=

[0070] As Figure 3 shown, the albedo represents the relative attenuation amount caused only by scattering within the surface or volume. Therefore, the albedo is a measure of the diffuse reflection of the medium. Specifically, there is the following mathematical relationship between the light radiation intensity, reflectance, and albedo of each optical path:

[0071]

[0072]

[0073]

[0074] Then it can be deduced that:

[0075]

[0076] Among them, the albedo is Ω, r is the reflectance, A 1 is the light radiation intensity of the first reflection, A 0 is the incident light radiation intensity, R 白 is the reflectance of the sample under the white substrate, and T is the transmittance.

[0077] In addition, when the sample is made of a transparent material, the reflectance R 0 of the sample is regarded as A 1 / A 0 Then there is:

[0078]

[0079] Certainly, the above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it accordingly. It is not intended to limit the protection scope of the present invention. All modifications made according to the spirit and essence of the main technical solution of the present invention should be covered within 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: According to the set environmental parameters and reflection conditions, a light path analysis model of the sample in the environment is constructed to obtain the radiation intensity of each light path under the light path analysis model. Each optical path in the optical path analysis model includes: incident light radiation intensity A0, once reflected light radiation intensity A1, once transmitted light radiation intensity A2, incident light radiation intensity A3 after being scattered and then reflected, incident light radiation intensity A4 after being scattered and then transmitted, incident light radiation intensity A5 after being reflected by the substrate, radiation intensity A6 after the substrate reflected light is reflected on the sample surface, radiation intensity A7 after the substrate reflected light enters the sample, transmission light radiation intensity A8 after the substrate reflected light enters the sample and then refracted back to the substrate, and radiation intensity A9 after the substrate reflected light enters the sample and is refracted twice; 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: T1= T2= Got it= Wherein, R is the reflectivity, T1 is the primary transmittance, T2 is the secondary transmittance, Tau is the optical depth, A0 is the radiation intensity of the incident light, A2 is the radiation intensity of the primary 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, and 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 light path analysis model in step S2 includes: a light path analysis model of incident light irradiating a sample, a light path analysis model of transmitted light irradiating a black and white substrate, and a light path analysis model of 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 R in step S4 can be calculated by the following formula: 。

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