[0034] The following describes the technical solutions in the embodiments of the present invention clearly and completely with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.
[0035] The embodiments of the present invention will be described in further detail below in conjunction with the accompanying drawings, such as figure 1 Shown is a schematic flow chart of a method for measuring environmental surface reflectance spectrum in visible light diffuse communication according to an embodiment of the present invention, and the method includes:
[0036] Step 11: With the help of an integrating sphere and a broad-spectrum light source, the spectra under the reflection of the surface materials of the environment to be tested and those without the surface materials of the environment to be tested are scanned respectively;
[0037] Step 12: Divide the obtained effective parts of the two spectra of the broad-spectrum light source point-to-point to obtain the relative reflectance spectrum of the environmental surface material to be measured;
[0038] In this step, the specific process of dividing the obtained effective parts of the two spectra of the broad-spectrum light source point to point is as follows:
[0039] Divide the non-zero continuous parts of the two spectra of the broad-spectrum light source output by the integrating sphere with and without the environmental surface material to be measured point-to-point to obtain the relative reflectance of the environmental surface material to be measured Rate spectrum, the specific formula is:
[0040] ρ relatively (λ)=Φ With reflection (λ)/Φ No reflection (λ)
[0041] Among them, Φ With reflection (λ) is the spectrum obtained under the reflection of the environmental surface material to be measured, Φ No reflection (λ) is the spectrum obtained without reflection from the surface material of the environment to be tested.
[0042] Step 13: With the integrating sphere and the monochromatic light source, the spectra under the reflection of the surface materials of the environment to be tested and those without the surface materials of the environment to be tested are scanned respectively;
[0043] Step 14: Divide the obtained effective parts of the two spectra of the monochromatic light source point-to-point to obtain the absolute reflectivity of the surface material of the environment to be measured for the monochromatic light;
[0044] In this step, the specific process of dividing the obtained effective parts of the two spectra of the monochromatic light source from point to point is as follows:
[0045] The two spectra of the monochromatic light source outputted by the integrating sphere under the conditions of the environmental surface material to be tested and without the environmental surface material to be tested are divided point-to-point in the part of the monochromatic light wavelength, so as to obtain the pair of environmental surface materials to be tested. The absolute reflectivity of the monochromatic light, the specific formula is:
[0046] ρ absolute (λ monochrome )=Φ With reflection (λ monochrome )/Φ No reflection (λ monochrome )
[0047] Among them, Φ With reflection (λ monochrome ) Is the spectrum obtained with the help of a monochromatic light source under the reflection of the environmental surface material to be measured, Φ No reflection (λ monochrome ) Is the spectrum obtained with the help of a monochromatic light source without the reflection of the environmental surface material to be measured, and the absolute reflectance is used as the reference reflectance.
[0048] Step 15: Based on the absolute reflectance of the obtained monochromatic light, according to the relative proportional relationship between the light of different wavelengths in the relative reflectance spectrum that has been obtained, the absolute reflectance of the light of other wavelengths in the wide spectral range is calculated proportionally rate;
[0049] Step 16: Combine the obtained absolute reflectances of all wavelengths to obtain an absolute reflectance spectrum in the entire wavelength range.
[0050] In this step, the specific calculation formula of the absolute reflectance spectrum in the entire wavelength range is:
[0051] ρ absolute (λ)=ρ relatively (λ)[ρ absolute (λ monochrome )/ρ relatively (λ monochrome )]
[0052] Where ρ relatively (λ monochrome ) Is the relative reflectance spectrum ρ relatively (λ) at the monochromatic light source wavelength λ monochrome The relative reflectance value at.
[0053] In specific implementation, the continuous wavelength range of the broad-spectrum light source is between 400 nanometers and 780 nanometers; and the center wavelength of the monochromatic light source is within the wavelength range of the broad-spectrum light source; and both the broad-spectrum light source and the monochromatic light source The light source should maintain stable spectral emission characteristics during the measurement.
[0054] In addition, during the measurement of the relative reflectance spectrum, the size of the environmental surface material to be measured is consistent with the shape and size of the light spot generated by the broad-spectrum light source; specifically, the size of the environmental surface The surface material of the sampled environment to be measured and the large-size spot generated by the broad-spectrum light source at the material position remain the same in shape and size, so that all light projected by the broad-spectrum light source undergoes the reflection of the surface material of the environment to be measured.
[0055] In the process of measuring the absolute reflectance of monochromatic light, the size of the surface material to be measured is consistent with the spot generated by the monochromatic light source in shape and size; specifically, the size of the surface material to be measured can be tailored , To keep the same shape and size as the small-sized spot produced by the monochromatic light source at the material position.
[0056] The process of the above measurement method is described in detail below with specific examples, such as figure 2 Shown is a schematic diagram of the test system structure used in the examples of the present invention, figure 2 The test system is composed of an integrating sphere part and a computer part. The integrating sphere part includes: (1) integrating sphere sphere and (2) integrating sphere chassis. During the measurement process, the broad-spectrum light source or monochromatic light source is fixed on the arm of the integrating sphere and the normal direction of the light source is vertically downward. The broad-spectrum light source or monochromatic light source projected to the bottom of the integrating sphere will form a circular spot .
[0057] Such as image 3 Shown is a schematic diagram of the internal structure of the integrating sphere when measuring a broad spectrum without the reflection of the environmental surface material to be measured in the example of the present invention. During the measurement, the integrating sphere must always be kept tightly closed, and only the relaxed spectrum is placed inside the sphere The light source is controlled by the computer to turn on the spectrum scanning function of the integrating sphere, and the broad spectrum is recorded as Φ without the reflection of the environmental surface material to be measured No reflection (λ).
[0058] Such as Figure 4 Shown is a schematic diagram of the internal structure of the integrating sphere when measuring the broad spectrum under the reflection of the environmental surface material to be measured in the example of the present invention. During the measurement, the integrating sphere is always kept in a tightly closed state, and a light source for relaxing the spectrum is placed inside the sphere. With the sample to be tested (ie the surface material of the environment to be tested). The surface material of the environment to be tested should be placed directly under the light source, and the size of the sample should be cut to be consistent with the spot size, so that all the light emitted by the light source will reflect and interact with the reflective material; then the computer will control the spectrum scanning of the integrating sphere. Function, record the broad spectrum under the reflection of the environmental surface material to be measured as Φ With reflection (λ). During the specific measurement process, since the light emission characteristics of the light source will slightly change over time, in order to improve the accuracy of the measurement results, the wide spectrum Φ No reflection (λ) and Φ With reflection (λ) Perform multiple measurements to average, thereby reducing measurement errors.
[0059] Then according to the formula ρ relatively (λ)=Φ With reflection (λ)/Φ No reflection (λ), obtain the relative reflectance spectrum of the surface material of the environment to be tested.
[0060] Such as Figure 5 Shown is a schematic diagram of the internal structure of the integrating sphere when measuring the monochromatic light spectrum without the reflection of the environmental surface material to be measured in the example of the present invention. During the measurement, the integrating sphere is always kept tightly closed, and only the inside of the sphere is placed Monochromatic light source: The spectrum scanning function of the integrating sphere is turned on through the computer control, and the monochromatic light spectrum is recorded as Φ without the reflection of the environmental surface material to be measured No reflection (λ monochrome ).
[0061] Such as Image 6 Shown is a schematic diagram of the internal structure of the integrating sphere when measuring the monochromatic light spectrum under the effect of the reflection of the environmental surface material to be measured in the example of the present invention. During the measurement, the integrating sphere is always kept tightly closed, and the inside of the sphere is placed and relaxed at the same time Monochromatic light source and small-sized sample to be tested (ie, the surface material of the environment to be tested). Among them, the small-sized sample to be tested should be placed directly under the light source, and cut to make the size of the sample consistent with the spot size, so that all the light emitted by the light source will reflect and interact with the reflective material; then the integrating sphere is controlled by the computer. Spectral scanning function, recording the monochromatic light spectrum under the reflection of the environmental surface material to be measured as Φ With reflection (λ monochrome ).
[0062] Then according to the formula ρ absolute (λ monochrome )=Φ With reflection (λ monochrome )/Φ No reflection (λ monochrome ) To obtain the absolute reflectivity of the surface material of the environment to be tested for the monochromatic light, and use the absolute reflectivity of the monochromatic light as a reference.
[0063] Such as Figure 7 Shown is a schematic diagram of a broad spectrum with and without reflection of environmental surface materials in the examples of the present invention, Figure 7 Middle: "---" is a linear curve which is a wide light source spectrum obtained by scanning without the reflection of the environmental surface material to be tested. In the embodiment of the present invention, a white LED spotlight is used; "-" is a linear The curve is the wide light source spectrum measured by the reflection of the environmental surface material to be tested. The surface material of the tested environment used in this example is taken from the ceiling material. Because the reflective material sample absorbs part of the power of the light signal, the remaining light Power reflection output, and this absorption and reflection has a certain wavelength selectivity, so the spectral level of "—" is the linear curve is lower than the spectral level of "---" is the linear curve, the difference between the two The value varies with the wavelength. Although the actual spectral range of a broad-spectrum light source is very wide, Figure 7 The middle display can cover the range of 300 nanometers to 1000 nanometers, but at the edge of the coverage range, that is, near 300 nanometers and 1000 nanometers, the spectrum is discontinuous. In order to divide the spectrum, the used spectral window must be shortened. Therefore, the spectral range used in the embodiment of the present invention is 400 nanometers and 800 nanometers.
[0064] Such as Figure 8 Shown is a schematic diagram of the relative reflectance spectrum of the environmental surface material to be measured in the example of the present invention, and the relative reflectance spectrum is according to the formula ρ relatively (λ)=Φ With reflection (λ)/Φ No reflection (λ) to obtain.
[0065] Such as Picture 9 Shown are the schematic diagrams of the monochromatic light spectrum with and without the reflection of environmental surface materials in the examples of the present invention. Specifically, the light source can be replaced with a monochromatic light source, and the type of the monochromatic light source can be a handheld green light. Laser, Picture 9 Middle: "---" is a linear curve which is the monochromatic light spectrum obtained by scanning without the reflection of the environmental surface material to be measured; "-" is a linear curve which is the scanning under the effect of the reflection of the environmental surface material to be tested Measured monochromatic light spectrum. Picture 9 It shows that the half-power wavelength range of the monochromatic light is about 5 nanometers in both cases, and the center wavelength of the light source is about 532 nanometers.
[0066] Such as Picture 10 Shown is a schematic diagram of the absolute reflectivity of the surface material of the environment to be tested to the monochromatic light in the examples of the present invention. Picture 9 Divide the two spectral curves in the middle to get Picture 10 The absolute reflectivity of the surface material of the environment to be measured to the monochromatic light given in the embodiment, because the monochromatic light in this embodiment is not an absolute single-wavelength light source, Picture 10 The absolute reflectance given in is also in an interval. This interval ranges between 400 nanometers and 700 nanometers, but the range below 532 nanometers and above 535 nanometers is limited by the low power of the light source, which corresponds to the reflection obtained in the above two intervals. The reflectivity has a huge error, and the reflectivity that can actually be used as a reference can only be selected between 532 nanometers and 535 nanometers. In order to improve the confidence of the results as much as possible, the reflectivity at the center wavelength is used as the reference reflectivity ρ in this embodiment. absolute (λ monochrome ).
[0067] Such as Picture 11 Shown is a schematic diagram of the absolute reflectance spectrum in the entire wavelength range obtained by calculation in the example of the present invention. The specific calculation process is based on the reflectance reference and the relative reflectance spectrum ρ obtained by the broad spectrum light source. relatively (λ) According to the formula ρ absolute (λ)=ρ relatively (λ)[ρ absolute (λ monochrome )/ρ relatively (λ monochrome )] is corrected to obtain the absolute reflectance spectrum ρ in the entire wavelength range absolute (λ).
[0068] In summary, the measurement method provided by the embodiments of the present invention has no special requirements for a wide-spectrum light source, so that the measurement cost is fully limited, and at the same time, it makes full use of the characteristics of the wide spectrum range to satisfy the need to broaden the wavelength range of the reflectance spectrum to be measured. At the same time, the data is calibrated through the portable monochromatic light source, so that the accuracy of the measurement results is further optimized and improved. The actual measurement time of the two measurement stages is completed within a few minutes, which further ensures the overall efficiency of the measurement process.
[0069] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or changes within the technical scope disclosed in the present invention. All replacements shall be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.
