A method and system for evaluating the spectral similarity of light sources with different color temperatures

Abstract

The present invention discloses a method and system for evaluating the spectral similarity of light sources with different color temperatures, relating to the field of spectral similarity. The method comprises: obtaining the power spectra of two colored light sources to be evaluated; determining the luminance spectrum of each colored light source based on the power spectra; determining whether the color temperatures of the two colored light sources are the same; if so, calculating the similarity of the two colored light sources based on the natural spectral similarity index formula; if not, calculating the similarity of the two colored light sources based on the spectral similarity index formula that takes color temperature into account. The present invention can effectively improve the computational accuracy of spectral similarity analysis and enhance the consistency of results, providing a more accurate spectral analysis tool for various fields involving color temperature variations and promoting the development and innovation of related technologies.

Description

Technical Field

[0001] The present invention relates to the technical field of spectral similarity, and more particularly to an evaluation method and system for evaluating the spectral similarity of light sources with different color temperatures. Background Art

[0002] The Natural Spectral Similarity Index (SRI) measures the degree of spectral similarity between a lighting source and natural light. It quantifies the value by comparing the spectral distribution of the light source under test with that of natural light at the same color temperature, taking into account the human eye's sensitivity to light of different wavelengths. This index aims to provide users with a more comfortable and healthier lighting environment, while also helping lighting designers better understand the spectral quality of their light sources.

[0003] The natural spectrum similarity index (NSI) is a quantitative value that represents the degree of similarity between the measured light source and a blackbody radiator at the same color temperature. The index is calculated by weighting the energy spectrum of the light source under test with the luminance function and comparing the weighted luminance spectra. However, this calculation ignores the crucial parameter of color temperature. In practice, as color temperature increases, the similarity increases, but the naked eye can still discern significant differences between the spectra. This indicates that the spectral similarity index exhibits an unexpected upward trend, while at the same time, the naked eye can clearly discern significant differences between the spectra.

[0004] Therefore, how to improve the accuracy and reliability of the spectral similarity analysis between the light source to be measured and natural light is an urgent problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a method and system for evaluating the spectral similarity of light sources with different color temperatures, which solves the dilemma that the calculated spectral similarity index results are significantly inconsistent with the actual observation results due to the increase in color temperature, thereby improving the accuracy and reliability of complex spectral analysis.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention discloses a method for evaluating the spectral similarity of light sources with different color temperatures, and the specific steps are as follows:

[0008] Step 1: Obtain the power spectra of the two colored light sources to be evaluated;

[0009] Step 2: Determine the luminous brightness spectrum of each of the colored light sources based on the power spectrum;

[0010] Step 3: Determine whether the color temperatures of the two colored light sources are the same. If the color temperatures are the same, calculate the similarity of the two colored light sources based on the natural spectrum similarity index formula; if the color temperatures are different, calculate the similarity of the two colored light sources based on the spectrum similarity index formula that takes color temperature into account.

[0011] Furthermore, the step 1 includes: placing the two colored light sources to be evaluated in a dark room, measuring the light intensity of each wavelength band of each colored light source by a photometer, and determining the power spectrum of each colored light source.

[0012] Furthermore, the step 2 includes:

[0013] Integrating the power spectrum with the human eye's visual function to obtain the luminous flux of each wavelength band of each colored light source;

[0014] Determining a photometric function between the radiation power and the luminous flux of the colored light source according to the luminous flux;

[0015] The power spectrum is multiplied by the luminosity function to obtain the luminous brightness spectrum.

[0016] Furthermore, the calculation formula of the luminous brightness spectrum is:

[0017] L i (λ,T)=I i (λ,T)×V(λ,T);

[0018] Among them, I i (λ,T) represents the power spectrum of the i-th colored light source, V(λ,T) represents the luminosity function, L i (λ,T) represents the luminous brightness spectrum of the i-th colored light source; λ represents the wavelength, and T represents the temperature.

[0019] Furthermore, the natural spectrum similarity index formula is:

[0020]

[0021] Among them, SRI represents the natural spectrum similarity index, L(λ,T) represents the overlapping area between the luminous brightness spectrum and the blackbody radiation, and L BR (λ,T) represents the brightness spectrum of blackbody radiation.

[0022] Furthermore, the spectral similarity index formula considering color temperature is:

[0023]

[0024] Among them, SRI CCT Indicates the spectral similarity index taking color temperature into consideration. CCT1 represents the color temperature of the comparison light source, and CCT2 represents the color temperature of the target light source.

[0025] The present invention also discloses an evaluation system for evaluating the spectral similarity of light sources with different color temperatures, comprising:

[0026] Power spectrum module: obtains the power spectra of the two colored light sources to be evaluated;

[0027] Luminous brightness spectrum module: determines the luminous brightness spectrum of each of the colored light sources according to the power spectrum;

[0028] Similarity calculation module: determines whether the color temperatures of the two colored light sources are the same. If the color temperatures are the same, the similarity of the two colored light sources is calculated according to the natural spectrum similarity index formula; if the color temperatures are different, the similarity of the two colored light sources is calculated according to the spectrum similarity index formula considering the color temperature.

[0029] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses an evaluation method and system for evaluating the similarity of spectra of light sources with different color temperatures, which has the following technical effects: By incorporating the color temperature factor, the present invention can more comprehensively reflect the true characteristics of spectral data, reduce the calculation error caused by color temperature changes, and thus significantly improve the calculation accuracy of the spectral similarity index. In a variety of actual scenarios of color temperature changes, the conclusions obtained by the present invention will be closer to the results of naked eye observation, effectively avoiding the obvious inconsistencies that may occur in the existing evaluation system, and enhancing the consistency, practicality and credibility of the results. The present invention is applicable to more fields involving color temperature changes, such as lighting engineering, color science, remote sensing monitoring, etc., providing more accurate spectral analysis tools for these fields and promoting the development and innovation of related technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0031] Figure 1 Schematic diagram of the overall process of an embodiment of the present invention.

[0032] Figure 2 Schematic diagram of calculating the spectral similarity between the D4 device and candlelight according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] The embodiment of the present invention discloses a method for evaluating the similarity of spectra of light sources with different color temperatures. Figure 1 The specific steps are as follows:

[0035] Step 1: Obtain the power spectra of the two colored light sources to be evaluated;

[0036] Step 2: Determine the luminous brightness spectrum of each colored light source based on the power spectrum;

[0037] Step 3: Determine whether the color temperatures of the two colored light sources are the same. If the color temperatures are the same, calculate the similarity of the two colored light sources based on the natural spectrum similarity index formula. If the color temperatures are different, calculate the similarity of the two colored light sources based on the spectrum similarity index formula that takes color temperature into account.

[0038] In a specific embodiment, step 1 includes: placing two colored light sources to be evaluated in a dark room, measuring the light intensity of each wavelength band of each colored light source using a photometer, and determining the power spectrum of each colored light source.

[0039] In a specific embodiment, step 2 includes:

[0040] Integrate the power spectrum with the human eye's visual function to obtain the luminous flux of each band of each colored light source;

[0041] Determine the photometric function between the radiant power of the colored light source and the luminous flux according to the luminous flux;

[0042] The luminous brightness spectrum is obtained by multiplying the power spectrum with the luminosity function.

[0043] Specifically, the human vision function was established by the Commission Internationale de L'Eclairage (CIE), a non-profit international standardization organization, based on extensive observations. Through extensive observations and experiments on the visual perception of many people, the CIE used an average method to determine the average relative sensitivity of the human eye to various wavelengths of light. This sensitivity is called the spectral luminous efficiency of a "standard photometric observer," also known as the human vision function. This is one of the foundational standards developed and promoted by the CIE in the lighting field, used to describe and quantify the human eye's sensitivity to different wavelengths of light. By establishing a standardized human vision function, people can more easily match and compare colors, which is of great significance in color measurement, color management, and color coordination. Furthermore, the human vision function quantifies the human eye's sensitivity to different wavelengths of light, revealing which wavelengths are most easily perceived and recognized by the human eye. This reveals the characteristics of human vision and provides guidance for the development of optical research.

[0044] Luminous flux is obtained by integrating the power spectrum with the human eye's visual function. Luminous flux is a physical quantity that describes the degree of visual stimulation of visible light emitted by a light source to the human eye. It reflects the portion of the light source's radiant energy within the visible light range that is perceived by the human eye. This leads to the luminosity function, which is the relationship between a light source's radiant power and luminous flux. The luminosity function can be used to describe a light source's luminous efficiency—the luminous flux produced per unit of radiant power. Multiplying the power spectrum with the luminosity function yields the luminous brightness spectrum. However, the spectral similarity index calculated in this way is subject to error, so color temperature is introduced as a metric for revision.

[0045] In a specific embodiment, the calculation formula of the luminous brightness spectrum is:

[0046] L i (λ,T)=I i (λ,T)×V(λ,T);

[0047] Among them, I i (λ,T) represents the power spectrum of the i-th colored light source, V(λ,T) represents the luminosity function, L i (λ,T) represents the luminous brightness spectrum of the i-th colored light source; λ represents the wavelength, and T represents the temperature.

[0048] In a specific embodiment, the natural spectrum similarity index formula is:

[0049]

[0050] Among them, SRI represents the natural spectrum similarity index, L(λ,T) represents the overlapping area between the luminous brightness spectrum and the blackbody radiation, and L BR (λ,T) represents the brightness spectrum of blackbody radiation.

[0051] In a specific embodiment, the formula for the spectral similarity index considering color temperature is:

[0052]

[0053] Among them, SRI CCT Indicates the spectral similarity index taking color temperature into consideration. CCT1 represents the color temperature of the comparison light source, and CCT2 represents the color temperature of the target light source.

[0054] In a specific embodiment, the spectra of three different light source devices are compared with candlelight.

[0055] Option 1: Select the spectrum of the B3 device and compare it with the spectrum of candlelight.

[0056] The color temperature of the light source of the B3 device is 1850K, and the color rendering index is 91.7Ra; the color temperature of the light source of candlelight is 1853K, and the color rendering index is 99.8Ra. i The brightness spectrum L is obtained by multiplying (λ, T) with the luminosity function V(λ, T) i (λ,T), and then integrate the two light sources separately, introducing the formula The spectral similarity index can be calculated to be 75.48%.

[0057] Under the newly established spectral similarity index system, the power spectrum I i The brightness spectrum L is obtained by multiplying (λ, T) with the luminosity function V(λ, T) i (λ, T), then integrate the two light sources separately, and then consider the influence of color temperature and introduce the formula The spectral similarity index can be calculated to be 75.36%.

[0058] Option 2: Select the spectrum of the C2 device and compare it with the spectrum of candlelight.

[0059] The color temperature of the light source of the C2 device is 1734K, and the color rendering index is 90.6Ra; the color temperature of the light source of the candlelight is 1853K, and the color rendering index is 99.8Ra. Under Jou's natural spectrum similarity index system, the power spectrum I i The brightness spectrum L is obtained by multiplying (λ, T) with the luminosity function V(λ, T) i (λ,T), and then integrate the two light sources separately, introducing the formula The spectral similarity index can be calculated to be 70.88%.

[0060] Under the newly established spectral similarity index system, the power spectrum I i The brightness spectrum L is obtained by multiplying (λ, T) with the luminosity function V(λ, T) i (λ, T), then integrate the two light sources separately, and then consider the influence of color temperature and introduce the formula The spectral similarity index can be calculated to be 66.33%.

[0061] Option 3: Select the spectrum of D4 device and candlelight for comparison, such as Figure 2 shown.

[0062] The color temperature of the light source of the D4 device is 1654K, and the color rendering index is 91.1Ra; the color temperature of the light source of candlelight is 1853K, and the color rendering index is 99.8Ra. Under Jou's natural spectrum similarity index system, the power spectrum I i The brightness spectrum L is obtained by multiplying (λ, T) with the luminosity function V(λ, T) i(λ,T), and then integrate the two light sources separately, introducing the formula The spectral similarity index can be calculated to be 67.81%.

[0063] Under the newly established spectral similarity index system, such as Figure 2 As shown, the power spectrum I i The brightness spectrum L is obtained by multiplying (λ, T) with the luminosity function V(λ, T) i (λ, T), then integrate the two light sources separately, and then consider the influence of color temperature and introduce the formula The spectral similarity index can be calculated to be 60.52%.

[0064] The embodiment of the present invention further discloses an evaluation system for evaluating the spectral similarity of light sources with different color temperatures, comprising:

[0065] Power spectrum module: obtains the power spectra of the two colored light sources to be evaluated;

[0066] Luminous brightness spectrum module: determines the luminous brightness spectrum of each colored light source based on the power spectrum;

[0067] Similarity calculation module: determines whether the color temperatures of two colored light sources are the same. If the color temperatures are the same, the similarity of the two colored light sources is calculated based on the natural spectrum similarity index formula; if the color temperatures are different, the similarity of the two colored light sources is calculated based on the spectrum similarity index formula considering color temperature.

[0068] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0069] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for evaluating the similarity of spectra of light sources with different color temperatures, characterized in that: The specific steps are as follows: Step 1: Obtain the power spectra of the two colored light sources to be evaluated; Step 2: Determine the luminous brightness spectrum of each of the colored light sources based on the power spectrum; Step 3: Determine whether the color temperatures of the two colored light sources are the same. If the color temperatures are the same, calculate the similarity of the two colored light sources according to the natural spectrum similarity index formula; if the color temperatures are different, calculate the similarity of the two colored light sources according to the spectrum similarity index formula considering color temperature; The natural spectrum similarity index formula is: Among them, SRI represents the natural spectrum similarity index, L(λ,T) represents the overlapping area between the luminous brightness spectrum and the blackbody radiation, and L BR (λ,T) represents the brightness spectrum of blackbody radiation; The formula for the spectral similarity index considering color temperature is: Among them, SBI CCT Indicates the spectral similarity index taking color temperature into consideration. CCT1 represents the color temperature of the comparison light source, and CCT2 represents the color temperature of the target light source.

2. The method for evaluating the spectral similarity of light sources with different color temperatures according to claim 1, characterized in that: The step 1 includes: placing the two colored light sources to be evaluated in a dark room, measuring the light intensity of each wavelength band of each colored light source by a photometer, and determining the power spectrum of each colored light source.

3. The method for evaluating the spectral similarity of light sources with different color temperatures according to claim 1, characterized in that: The step 2 includes: Integrating the power spectrum with the human eye's visual function to obtain the luminous flux of each wavelength band of each colored light source; Determining a photometric function between the radiation power and the luminous flux of the colored light source according to the luminous flux; The power spectrum is multiplied by the luminosity function to obtain the luminous brightness spectrum.

4. The method for evaluating the spectral similarity of light sources with different color temperatures according to claim 1, wherein: The calculation formula of the luminescence brightness spectrum is: L i (λ,T)=I i (λ,T)×V(λ,T); Among them, I i (λ,T) represents the power spectrum of the i-th colored light source, V(λ,T) represents the luminosity function, L i (λ),T) represents the luminous brightness spectrum of the i-th colored light source; λ represents the wavelength, and T represents the temperature.

5. An evaluation system for evaluating the similarity of spectra of light sources with different color temperatures, applying the evaluation method for evaluating the similarity of spectra of light sources with different color temperatures according to any one of claims 1 to 4, characterized in that: include: Power spectrum module: obtains the power spectra of the two colored light sources to be evaluated; Luminous brightness spectrum module: determines the luminous brightness spectrum of each of the colored light sources according to the power spectrum; Similarity calculation module: determines whether the color temperatures of the two colored light sources are the same. If the color temperatures are the same, the similarity of the two colored light sources is calculated according to the natural spectrum similarity index formula; if the color temperatures are different, the similarity of the two colored light sources is calculated according to the spectrum similarity index formula considering the color temperature; The natural spectrum similarity index formula is: Among them, SRI represents the natural spectrum similarity index, L(λ,T) represents the overlapping area between the luminous brightness spectrum and the blackbody radiation, and L BR (λ,T) represents the brightness spectrum of blackbody radiation; The formula for the spectral similarity index considering color temperature is: Among them, SRI CCT Indicates the spectral similarity index taking color temperature into consideration. CCT1 represents the color temperature of the comparison light source, and CCT2 represents the color temperature of the target light source.

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