Testing device and method for road luminous marking environment display degree

Abstract

The application provides a device and method for testing the environmental display degree of road luminous marking, and belongs to the technical field of road marking performance testing. The device is composed of three units, i.e. an illumination environment, a road surface environment and optical collection. In the illumination environment unit, the luminous marking sample placed on the road surface environment unit is excited by light, then the illumination environment in the device is adjusted to reach the target environmental illumination at the plane where the luminous marking sample is located, the luminance of the luminous marking and the road surface environment area is collected respectively, and the environmental display degree and the effective luminous duration of the luminous marking under the illumination environment and the road surface environment are calculated.

Description

Technical Field

[0001] This invention belongs to the field of road marking performance testing technology, specifically relating to a testing device and method for the visibility of luminous road markings under different dark environments and road conditions. Background Technology

[0002] As an important safety and guidance facility in the road traffic system, road markings have the core function of providing drivers with clear, continuous, and reliable visual references, thereby regulating vehicle trajectories, defining right-of-way, and conveying traffic rule information. Currently, the reflective performance of traditional road markings at night mainly relies on the retroreflective effect formed by glass microbeads sprinkled on the surface of the markings. However, there are two major problems in the use of these markings: (1) In severe weather conditions such as heavy rain and fog, rainwater easily covers the surface of the glass beads, resulting in a significant reduction in the retroreflective performance of the glass beads and a decrease in the reflective effect of the markings; (2) Under the wear and tear of car tires, the glass microbeads are easily worn off from the surface of the markings, causing a significant decrease in the reflective effect of the markings and resulting in poor guidance effect.

[0003] To overcome the limitations of traditional reflective markings, road luminescent markings based on long-afterglow luminescent materials have emerged. Road luminescent markings are typically prepared by incorporating long-afterglow luminescent powder, fillers, and additives into a film-forming material. The long-afterglow luminescent powder is often made of yellow-green strontium aluminate. This type of material can absorb and store light energy under external light sources and continuously release visible light in low-light environments, giving the markings a certain degree of active luminescence at night.

[0004] In recent years, illuminated road markings have been gradually used in tunnel entrances and exits, urban pedestrian walkways, scenic roads and other scenarios, which can improve the nighttime visibility of markings at road boundaries and warning areas to a certain extent. At present, the engineering application of illuminated road markings is still in the promotion and verification stage. The existing test methods for their luminous performance mainly focus on testing the absolute luminous performance of sheet-like samples, such as spectral characteristics, luminous brightness, and afterglow duration, which have the following obvious defects: (1) Detached from the actual road surface background. Existing test methods usually only test the luminous brightness of the marking sample itself, without considering the influence of the color brightness, material type and usage status of the road surface to be coated on the display effect. (2) Lack of relative contrast evaluation index and effective luminous duration that can comprehensively reflect the relationship between "marking-road surface-ambient light". Existing methods mostly use the brightness of the marking itself or the afterglow decay time as the evaluation basis, which is difficult to reflect the actual visual effect under the combined effect of ambient light and road surface background brightness.

[0005] Therefore, it is necessary to provide a testing device and method suitable for the environmental visibility of road luminous markings, in order to solve the problems of existing testing technologies that are detached from the actual road surface background, make it difficult to uniformly quantify the display effect of markings, and lack the accuracy of evaluating the effective luminous duration. Summary of the Invention

[0006] To address the aforementioned shortcomings in existing technologies, this invention provides a testing device and method for the environmental visibility of luminous road markings. By constructing a controllable three-factor coupled testing system of "ambient light-road background-luminous markings," it enables quantitative testing and evaluation of the environmental visibility and effective luminous duration of luminous markings under different darkness levels and road background conditions, filling the gap in the existing luminous marking testing system that lacks environmental adaptability evaluation methods.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] The present invention provides a testing device for the environmental visibility of road luminous markings, characterized in that it includes an illumination environment unit, a road surface environment unit, and an optical acquisition unit.

[0009] The illumination environment unit includes a dark chamber, one ultraviolet excitation source, and two LED panel light sources. The dark chamber is a light-shielding box with a sealed door and black inner walls, used to create a relatively enclosed low-illuminance testing environment. The ultraviolet excitation source is fixed to the top of the dark chamber with bolts, and its wavelength range is 365nm±10nm, with a rated power of not less than 10W, used for storing light and exciting the road luminous marking sample. The two LED panel light sources are symmetrically fixed to both sides of the ultraviolet excitation source with bolts. The brightness of the LED panel light sources is adjustable in three levels, used to adjust the illuminance at the plane where the road luminous marking sample is located to the target ambient illuminance.

[0010] The road surface environment unit includes two parallel limiting strips and five square road surface color plates with different color brightness levels. The two limiting strips are fixed to the bottom plate of the dark box by bolts, and the spacing between them is the same as the side length of the square road surface color plates. During testing, the selected road surface color plate is placed between the two limiting strips to ensure the consistency of the road surface color plate's placement position during the testing process.

[0011] The optical acquisition unit includes a luminance meter, an illuminance meter, a colorimeter, and an adjustable bracket. The colorimeter is used to measure the color parameters of the surface to be coated with the illuminated road markings and the surface of the road surface color plate; the illuminance meter is used to measure the illuminance at the plane where the illuminated road marking sample is located and to confirm that the illuminance meets the target ambient illuminance E. j The accuracy must be higher than 0.01 Lux; the luminance meter is used to collect the luminance values ​​of the road luminous marking sample and the adjacent road surface color plate. The probe is mounted on an adjustable bracket, and the accuracy must be higher than 0.001 cd / m. 2 .

[0012] Furthermore, the power of a single LED panel light source does not exceed 10W. When the indoor ambient illuminance is no greater than 0.1 Lux, the sealed door of the dark chamber is opened, and by adjusting the brightness of the LED panel light source, the illuminance at the plane where the marking sample is located can be at any of the following target ambient illuminance levels E. j The illuminance levels are: E1 for complete darkness with an intensity of no more than 0.1 Lux, E2 for low light with an intensity of more than 0.1 Lux but no more than 1 Lux, and E3 for moonlight with an intensity of more than 1 Lux but no more than 10 Lux, to simulate different low-light environments on outdoor roads.

[0013] Furthermore, the upper surface of the five road surface color plates is marked with two limiting lines. The two limiting lines are parallel to a set of edges of the road surface color plates and are symmetrically distributed with respect to the geometric center of the upper surface of the road surface color plates. The spacing between the two limiting lines is consistent with the width of the road luminous marking sample, which is used to calibrate the placement position of the road luminous marking sample on the road surface color plates.

[0014] Furthermore, the upper surface color of the five road surface color swatches, under the CIE Lab colorimetric system, has a lightness value L. si (i = 1, 2, 3, 4, 5) are located in five ranges, where L s1 Satisfying 0≤L s1 ≤20, L s2 Satisfying 20 < L s2 ≤40, L s3 Satisfying 40 < L s3 ≤60, L s4 Satisfying 60 < L s4 ≤80, L s5 Satisfying 80 < L s5 ≤100, and a for each color plate si value and b si The absolute values ​​of the values ​​are all no greater than 5, so that the color swatches of each road surface mainly reflect the differences in brightness, and are used to simulate the background brightness characteristics of newly paved asphalt roads, aged asphalt roads, old asphalt roads, light-colored asphalt roads and cement concrete roads respectively.

[0015] The present invention also provides a method for testing the environmental visibility of road illuminated markings, using the above-mentioned testing device, and comprising the following steps:

[0016] First, the lightness value L, as well as the a and b values, of the road surface to be coated with the illuminated road markings were measured using a colorimeter. Calculate the color difference ΔE between the road surface and the five road surface color plates respectively, select the road surface color plate with the smallest ΔE as the road surface color plate that is closest to the color of the road surface to be coated, and place it in the middle of the parallel limit strip at the bottom of the dark box.

[0017] Next, road luminous marking paint was coated onto a long strip of cement asbestos board with a thickness not exceeding 1 mm and a length equal to the side length of the road surface color board, thus preparing three road luminous marking samples. Each road luminous marking sample was dried in a 60℃ oven for 2 hours, and then placed in an independent dark environment for 24 hours to avoid light.

[0018] Subsequently, a light-shielded road luminous marking sample was placed in the center of the upper surface of the road surface color plate, with the two long sides of the sample aligned with the two limit lines on the upper surface of the road surface color plate. After excitation by ultraviolet light source for 20 minutes, the ultraviolet light source was turned off.

[0019] Furthermore, within 30 seconds after excitation, in an indoor environment with an illuminance of no more than 0.1 Lux, the sealed door of the dark chamber is opened, the brightness of the LED panel light source is adjusted, and the illuminance value at the plane where the marked sample is located is confirmed by a lux meter to reach the target ambient illuminance E. j Afterward, let it stand for 5 minutes to allow the road luminous marking sample to form a relatively stable brightness state under the target ambient illumination conditions.

[0020] Furthermore, the angle of the support is adjusted so that the luminance meter probe is perpendicularly attached to the luminance acquisition point on the surface of the marking sample, and the luminance L of the marking sample is measured. m Readjust the bracket so that the luminance meter probe is vertically attached to the luminance acquisition points on the adjacent pavement color plates on both sides of the pavement marking sample. Measure the two pavement background luminance values ​​and take the average value as the luminance L of the adjacent pavement color plates. b According to the formula Calculate the environmental visibility of the road markings under the current road background and ambient light conditions. The higher the environmental visibility, the more significant the difference in brightness between the road markings and the road background, and the more prominent its display effect under the corresponding environmental conditions.

[0021] Furthermore, while keeping the current road surface color and ambient illuminance unchanged, the brightness acquisition step is repeated every 10 minutes to obtain the ambient visibility D of the luminous marking sample at different afterglow times. The afterglow time corresponding to when the ambient visibility D decays to 4 is taken as the effective luminous duration of the road luminous marking under the current road surface environment and lighting environment.

[0022] Finally, keeping the selected pavement color unchanged, replace the pavement marking sample and set the target ambient illuminance E. j The ambient illuminance modes were adjusted to the other two levels, and the above process of ultraviolet excitation, ambient illuminance adjustment, brightness acquisition, and ambient visibility calculation was repeated to obtain the ambient visibility and effective luminescence duration of the prepared road luminous marking sample under selected road surface conditions and different lighting environments.

[0023] Beneficial effects of the present invention

[0024] (1) The test device provided by the present invention is equipped with five road surface color plates with different brightness levels, and can simulate three environmental illuminance levels under a selected road surface background, thus constructing a test platform with three factors coupled: ambient light, road surface background and luminous markings.

[0025] (2) The environmental visibility index and effective luminous duration proposed in this invention comprehensively reflect the coupling effect of the luminous brightness of the marking, the background brightness of the road surface and the ambient light. Compared with the traditional single parameters such as absolute luminous brightness or afterglow decay curve, it can more realistically characterize the visibility effect of luminous markings in the actual road environment. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the test device structure of the present invention.

[0027] In the diagram, 1-shielding box; 2-LED panel light source; 3-ultraviolet excitation light source; 4-parallel limiting strip; 5-road surface color plate; 6-luminous marking sample; 7-illuminance meter; 8-hinge; 9-black inner wall; 10-sealed door; 11-adjustable bracket; 12-illuminance meter probe.

[0028] Figure 2 This is a schematic diagram of the test points for the marking sample of the present invention.

[0029] Figure 3 The environmental visibility of the luminous markers was measured under 15 test conditions, with a 5-minute afterglow period.

[0030] Figure 4 For different ratios of luminous markings in L s5 Environmental visibility at different afterglow times under E1. Detailed Implementation

[0031] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0032] Example

[0033] In this embodiment, the darkroom of the lighting environment unit is welded from 3mm thick 6061 aluminum alloy sheet, with external dimensions of 40cm (length) × 30cm (width) × 50cm (height). The inner wall of the enclosure is uniformly coated with a black coating. The front of the enclosure has a 30cm × 25cm sealed door, which is double-sealed with a 15mm wide light-shielding rubber sealing strip.

[0034] In this embodiment, the LED panel light source is a high color rendering white LED panel with a color temperature of 5000K. Each LED panel measures 10cm × 10cm, has a power of 8W, and its brightness is continuously adjustable. Two LED panels are fixed to the top left and right sides of the dark chamber with bolts. When the dark chamber's sealed door is opened under indoor ambient illuminance conditions not exceeding 0.1 Lux, the illuminance at the plane containing the luminous marker sample is calibrated in real time using an illuminance meter. By adjusting the brightness of the LED panel light source, the illuminance at that plane is made to reach the target ambient illuminance. The target ambient illuminance E... j It includes three modes: E1, a completely dark mode with an illuminance of no more than 0.1 Lux; E2, a low-light mode with an illuminance of more than 0.1 Lux but no more than 1 Lux; and E3, a moonlight mode with an illuminance of more than 1 Lux but no more than 10 Lux.

[0035] In this embodiment, the ultraviolet excitation source is an ultraviolet LED lamp assembly with a peak wavelength of 365nm±10nm and a rated power of 20W, which is fixed to the top center of the dark box by bolts. The excitation time of the ultraviolet excitation source is set to 20 minutes.

[0036] In this embodiment, the road surface environment unit is equipped with five road surface color swatches, each with dimensions of 20cm × 20cm × 1mm. The lightness values ​​(L) of the upper surfaces of the five road surface color swatches, under the CIE Lab colorimetric system, fall within the ranges of 0≤L≤20, 20<L≤40, 40<L≤60, 60<L≤80, and 80<L≤100, respectively, and the absolute values ​​of a and b are both no greater than 5. Each road surface color swatch has two limiting lines parallel to a set of edges marked on its upper surface. These limiting lines are marked with thin lines no wider than 0.5mm, and are symmetrically distributed with respect to the geometric center of the upper surface of the road surface color swatch, with a distance of 4cm between them.

[0037] In this embodiment, the parallel limiting strips are made of rectangular cross-section limiting iron bars. Each limiting iron bar is 20cm long, 5mm wide, and 1mm high. The limiting iron bars are welded to the central area of ​​the upper surface of the bottom plate of the dark box. The two limiting iron bars are arranged in parallel, with a 20cm distance between their inner sides.

[0038] In this embodiment, the marking paint uses SrAl2O4:Eu 2+ Dy 3+ The preparation of long-afterglow luminescent materials, represented by [example material], and silicone-acrylic emulsion was carried out. Long-afterglow luminescent powder was added to the silicone-acrylic emulsion at a mass ratio of 30%. After thorough mixing, the luminescent marking paint was applied to a strip of cement-asbestos board measuring 20cm (length) × 4cm (width) × 1mm (height) using a scraping method to prepare luminescent marking samples. The samples were dried in a 60℃ oven for 2 hours and then placed in a dark environment for 24 hours.

[0039] In this embodiment, a TES-1339 illuminance meter is selected and placed beside the plane of the road marking sample with the probe facing upwards to measure the ambient illuminance. An ST-86LA screen luminance meter is selected, with its lens vertically downwards attached to the luminance acquisition point of the road marking sample and the road background to collect luminance data of the marking area and the road background area, and calculate the ambient visibility D value. The adjustable bracket is a flexible bracket, with one end fixed to the bottom plate of the darkroom and the other end holding the luminance meter probe. The position and angle of the luminance meter probe relative to the luminance acquisition point on the surface of the road marking sample or road color plate are adjusted by bending the flexible bracket.

[0040] In this embodiment, following the test method steps S1 to S7 described above, five road surface color swatches were used as the background for the road surface to be coated for verification testing. The environmental visibility was tested under three different ambient light modes when the afterglow time was 5 minutes. Each condition was measured three times, and the average value was taken. One set of test results is shown in Table 1, and all test results are as follows: Figure 3 As shown.

[0041] Table 1 shows the environmental visibility (D) of luminous road markings at 5 minutes afterglow under moonlight conditions E3 and different road backgrounds.

[0042]

[0043] From Table 1 and Figure 3 It can be seen that, at the same afterglow time, the ambient visibility D decreases as the brightness level of the road surface swatch increases. Taking the moonlight setting E3 as an example, when the road surface swatch changes from L... s1 Change to L s5 At that time, the ambient visibility D decreased from 25.4 to 8.7, indicating that a light-colored road surface background increases background brightness, thereby weakening the brightness contrast between the illuminated markings and the road surface. Meanwhile, under the same road surface color swatch brightness, the ambient visibility D decreases as the ambient illuminance level increases. (Using L...) s5 Taking the road surface color chart as an example, the ambient visibility D values ​​under the full black setting E1, low light setting E2, and moonlight setting E3 are 37.9, 14.0, and 8.7, respectively, indicating that as the ambient illuminance increases, the brightness of the road surface background also increases, and the relative display advantage of luminous markings weakens.

[0044] The above results demonstrate that the testing device of this invention can distinguish the effects of different road surface background brightness and different ambient illumination conditions on the display effect of illuminated road markings. The brighter the road surface background and the higher the ambient illumination, the lower the environmental visibility of the illuminated markings. This result is consistent with the display pattern of illuminated road markings in actual low-illuminance road environments, indicating that the testing method can be used to evaluate the visibility differences of illuminated road markings under different road surface backgrounds and lighting conditions.

[0045] This embodiment further compares the effective luminescence duration of pavement marking samples with different luminescent powder contents under the same road surface background and lighting conditions. The pavement color swatch uses a brightness value of L. s5 The color swatch was set to ambient illuminance level E1 (full black), and the ambient visibility was measured at different afterglow times. Figure 4 As shown in Table 2, the effective duration results for each sample are as follows.

[0046] Table 2. Marking samples with different mix ratios at L s5 Road background, 5-minute D value under E1 black mode, and effective luminescence duration

[0047]

[0048] As shown in Table 2, the higher the luminescent powder content of the road marking samples, the higher the initial environmental visibility (D) and the longer the effective luminescence duration. The effective luminescence duration of sample W4 is approximately 2.3 times that of sample W1, indicating that increasing the luminescent powder content of road luminous markings is an effective way to extend their effective visibility time.

[0049] Based on the above test results, the testing device and method provided by this invention can systematically and quantitatively evaluate the environmental visibility of luminous road markings under different road backgrounds and ambient illumination conditions. The obtained environmental visibility and effective luminous duration can provide a scientific basis for optimizing the material formulation, engineering selection, and maintenance management of luminous road markings.

Claims

1. A testing device for the environmental visibility of luminous road markings, characterized in that, include: The system comprises a lighting environment unit, a road surface environment unit, and an optical acquisition unit. The lighting environment unit includes a darkroom, one ultraviolet (UV) excitation source, and two LED panel light sources. The darkroom is a light-shielding enclosure with a sealed door and black inner walls. The UV excitation source is bolted to the top of the darkroom; its wavelength range is 365nm ± 10nm, and its rated power is not less than 10W. The two LED panel light sources are symmetrically bolted to both sides of the UV excitation source, and their brightness is adjustable in three levels. The road surface environment unit includes two parallel limiting strips and five square road surface color plates with different brightness levels. The two parallel limiting strips are bolted to the bottom plate of the darkroom, with a spacing equal to the side length of the square road surface color plates. The optical acquisition unit includes a colorimeter, an illuminance meter, and a luminance meter connected to the bottom of the darkroom via an adjustable bracket.

2. The testing device for the environmental visibility of road luminous markings according to claim 1, characterized in that, The power of a single LED panel light source does not exceed 10W, and when the indoor ambient illuminance is no greater than 0.1Lux, the illuminance at the plane where the marking sample is located can be adjusted to the following three levels of ambient illuminance E. j The following are the illuminance values: E1 for complete darkness is no greater than 0.1 Lux; E2 for low light is greater than 0.1 Lux and no greater than 1 Lux; and E3 for moonlight is greater than 1 Lux and no greater than 10 Lux.

3. The testing device for the environmental visibility of road luminous markings according to claim 1, characterized in that, The upper surface colors of the five road surface color swatches, under the CIE Lab colorimetric system, have a lightness value L. si (i = 1, 2, 3, 4, 5) are located in five ranges, where L s1 Satisfying 0≤L s1 ≤20, L s2 Satisfying 20 < L s2 ≤40, L s3 Satisfying 40 < L s3 ≤60, L s4 Satisfying 60 < L s4 ≤80, L s5 Satisfying 80 < L s5 ≤100, and a for each color plate si value and b si The absolute values ​​of all values ​​are no greater than 5. Each of the five road surface color plates has two limiting lines marked on its upper surface. These two limiting lines are parallel to a set of edges of the road surface color plate and are symmetrically distributed with respect to the geometric center of the upper surface of the road surface color plate. The spacing between them is consistent with the width of the road illuminated marking sample.

4. A test method for the environmental visibility of luminous road markings, characterized in that, Using the road illuminated marking environmental visibility testing device as described in claim 1, the environmental visibility of a type of road illuminated marking under three levels of ambient illuminance is tested, including the following steps: S1. Use a colorimeter to measure the brightness values ​​L, a, and b of the road surface to be coated with the luminous markings. Calculate the color difference ΔE between the road surface and the five road surface color plates. Select the road surface color plate with the smallest ΔE and place it in the middle of the parallel limiting strip at the bottom of the dark box. S2. Apply road luminous marking paint to a long strip of cement asbestos board with a thickness not exceeding 1 mm and a length the same as the side length of the road surface color board, and prepare 3 road luminous marking samples: After drying each road luminous marking sample in a 60℃ oven for 2 hours, place them in an independent dark environment for 24 hours to avoid light. S3. Place a light-shielded road luminous marking sample in the center of the upper surface of the road surface color plate, aligning the two long sides of the sample with the two limit lines on the upper surface of the road surface color plate. Excite the marking sample with ultraviolet light source for 20 minutes, then turn off the ultraviolet light source. S4. Within 30 seconds after excitation, in a relatively dark environment with an indoor illuminance of no more than 0.1 Lux, open the sealed door of the dark chamber, adjust the brightness of the LED panel light source, and use a lux meter to confirm that the illuminance value at the plane where the marked sample is located reaches the target ambient illuminance E. j After (Lux), keep the brightness of the LED panel light source unchanged and let it stand for 5 minutes. S5. Adjust the support so that the luminance meter probe is perpendicularly attached to the luminance acquisition point on the surface of the marking sample, and measure the luminance L of the marking sample. m (cd / m 2 Then, the bracket was adjusted again so that the luminance meter probe was vertically attached to the luminance acquisition points on the adjacent pavement color plates on both sides of the pavement marking sample. The two pavement background luminance values ​​were measured, and the average value was taken as the luminance L of the adjacent pavement color plates. b (cd / m 2 ), and by Calculate the environmental visibility of the road markings under the current road surface and lighting conditions. S6. Under the condition of keeping the current road surface color and ambient illuminance unchanged, repeat step S5 every 10 minutes to obtain the ambient visibility D of the luminous marking sample at different afterglow times. Stop the test when the ambient visibility D decays to 4, and take the corresponding afterglow time as the effective luminous duration of the road luminous marking under the current road surface environment and lighting environment. S7. Replace the luminous marker sample and adjust the target ambient illuminance E. j Adjust to the other two ambient illuminance modes respectively, and repeat steps S3 to S6 to obtain the ambient visibility and effective luminous duration of the marking sample under the selected road surface color and the other two lighting conditions.

5. The method for testing the environmental visibility of road illuminated markings according to claim 4, characterized in that, In step S1, the color difference ΔE between the road surface and the five road surface color swatches is determined by the lightness values ​​L, a, and b measured on the road surface, and the lightness values ​​L on the five road surface color swatches. si a si value, b si Value, by calculate.

6. The method for testing the environmental visibility of road illuminated markings according to claim 4, characterized in that, In step S5, the marking brightness acquisition point is the geometric center of the marking sample, and the road surface brightness acquisition point is the two road surface color plate points located at the midpoint of the marking sample's length direction and 5cm away from the two side lines of the marking sample.

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