Analysis method for light reduction induction design of highway tunnel portal based on driving safety

Abstract

This invention discloses a design and analysis method for reducing light intensity at highway tunnel entrances based on driving safety. It relates to the field of tunnel entrance light intensity reduction and guidance design, and includes: This invention simultaneously acquires ambient light illuminance data and driver pupil diameter and reaction time in a simulation platform to locate visual load abrupt change sections, calculates illuminance attenuation rate and driver pupil area change rate, determines pupil matching degree, and identifies mismatched road sections; analyzes the alignment and synergy between the brightness transition gradient of the sunshade and the visual guidance intensity of the colored pavement in the spatial distribution of the mismatched road sections, determines the cause of the load abrupt change, and optimizes the color and stripe spacing of the colored pavement based on the cause; after determining the cause of the load abrupt change, it prioritizes adjusting the light transmittance and length of the sunshade, and then optimizes the synergistic optimization strategy of the color and stripe spacing of the colored pavement; this invention enables light reduction measures and guidance measures to cooperate spatially, alleviating the driver's light and dark adaptation when entering and exiting the tunnel.

Description

Technical Field

[0001] This invention belongs to the field of tunnel entrance light reduction guidance design technology, and relates to a method for analyzing and designing light reduction guidance for highway tunnel entrances based on driving safety. Background Technology

[0002] The light reduction guidance design method at highway tunnel entrances is used to alleviate the problem of light and dark adaptation for drivers when entering and exiting tunnels through facilities such as sunshades or colored pavements, thereby reducing the risk of traffic accidents at tunnel entrances.

[0003] However, existing designs for reducing light at the entrance of highway tunnels have the following shortcomings: First, existing technologies typically determine the length of the sunshade based on experience and select the light transmittance and perforation size of the sunshade by referring to engineering analogies. However, the change in the diameter of the human pupil is constrained by the dynamics of the iris muscles, and the maximum rate of accommodation is limited. Meanwhile, the spatial illuminance gradient at the tunnel entrance changes rapidly, and the illuminance drops sharply over a short distance. The illuminance attenuation rate is very likely to exceed the physiological rate that the pupil can follow, causing the brightness transition of the sunshade to end prematurely before the driver's pupil has completed its accommodation, resulting in a brightness transition discontinuity. Drivers lose light reduction protection on critical road sections, and their visual load increases sharply.

[0004] Secondly, existing technologies typically select red or yellow for colored pavement, use equally spaced stripes, and determine the paving length based on empirical values ​​derived from speed reduction warning signs. However, variations in the reflectivity and stripe spacing of colored pavement directly affect the driver's visual perception of vehicle speed and direction. Equally spaced stripes flash at a constant frequency in the driver's field of vision, failing to create the visual illusion of speed changes to proactively induce the driver to slow down in advance on sections of road with concentrated visual load.

[0005] Finally, existing technologies typically design sunshades and colored pavements as separate facilities. The locations where the brightness transition of the sunshade is most drastic and the locations where the visual guidance of the colored pavement is strongest may be spatially misaligned. Drivers cannot obtain synchronized visual guidance at key locations where brightness changes abruptly, which cannot alleviate the driver's problem of light and dark adaptation, and the risk of traffic accidents at the tunnel entrance still exists. Summary of the Invention

[0006] In view of this, in order to solve the problems mentioned in the background art, the present invention provides a method for design and analysis of light reduction guidance at highway tunnel entrances based on driving safety.

[0007] The objective of this invention can be achieved through the following technical solution: a design and analysis method for reducing light at the entrance of a highway tunnel based on driving safety, comprising: S1, acquiring the ambient light intensity data of the tunnel entrance approach section and the driver's pupil diameter and reaction time in the simulation platform, and locating the visual load mutation section where the pupil diameter is abnormal and the reaction time increases sharply.

[0008] S2. Calculate the illuminance attenuation rate and the driver's pupil area change rate based on the ambient light illuminance data and the driver's pupil diameter, respectively.

[0009] S3. Determine the pupil matching degree based on the illuminance attenuation rate and the driver's pupil area change rate in the visual load abrupt change section, and determine the mismatched road section based on the pupil matching degree.

[0010] S4. Analyze the spatial synergistic relationship between the brightness transition gradient of the shade canopy and the visual guidance intensity of the colored pavement in the mismatched road section to determine the cause of the load change.

[0011] S5. Based on the cause of the sudden load change, adjust the length of the sunshade according to the brightness transition gradient of the sunshade and the rate of change of the driver's pupil area, and optimize the color of the colored road surface and the stripe spacing until the pupil matching degree returns to the normal range.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention obtains light environment illuminance data and driver pupil diameter and reaction time synchronously in the simulation platform, locates the visual load change section, calculates the illuminance attenuation rate and driver pupil area change rate, judges the pupil matching degree and determines the mismatch section, realizes the point-by-point comparison between the light environment change rate and the driver pupil physiological adjustment rate, solves the problem of brightness transition discontinuity caused by the illuminance attenuation rate exceeding the pupil can follow the physiological rate, and ensures that the driver is always under light reduction protection during the entire pupil adjustment process.

[0013] (2) This invention analyzes the alignment and synergy between the brightness transition gradient of the shade canopy and the visual guidance intensity of the colored pavement in the spatial distribution of the mismatched road section, determines the cause of the load change, and optimizes the color and stripe spacing of the colored pavement according to the cause, reduces the additional light stimulation of the pupil by the road surface reflection brightness, and produces a deceleration prompt effect in perception, inducing the driver to actively reduce the vehicle speed in the road section with concentrated visual load, and making up for the deficiency that the equally spaced stripes cannot form a change in vehicle speed perception.

[0014] (3) This invention prioritizes adjusting the light transmittance and length of the shading canopy after determining the cause of the sudden load change, and then optimizes the synergistic optimization strategy of the color of the colored pavement and the stripe spacing, so that the light reduction measures and the guidance measures are coordinated in space, which alleviates the problem of drivers adapting to light and dark when entering and exiting the tunnel and reduces the risk of traffic accidents at the tunnel entrance. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a diagram illustrating the implementation steps of the method of the present invention;

[0017] Figure 2 This is a graph showing the changes in illuminance in the driver's seat and pupil diameter according to the present invention.

[0018] Figure 3 This is a pseudo-color map of road surface brightness under the shading canopy of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see Figure 1 As shown, the present invention provides a design analysis method for reducing light at the entrance of a highway tunnel based on driving safety, including: S1, acquiring the ambient light intensity data of the tunnel entrance approach section and the driver's pupil diameter and reaction time in the simulation platform, and locating the visual load mutation section where the pupil diameter is abnormal and the reaction time increases sharply.

[0021] Considering that the adaptation between light and dark at the tunnel entrance is a major cause of traffic accidents in highway tunnels, and that the driver's pupil diameter changes from a stable state to a continuous increase when the illuminance decreases from outside to inside the tunnel, obtaining ambient light illuminance data and the driver's pupil diameter and reaction time includes: constructing a three-dimensional virtual scene of the approach section of the tunnel entrance in a simulation platform based on the actual terrain outside the tunnel and the tunnel design data, and recreating the real light environment by simulating natural light sources and tunnel lighting fixtures.

[0022] In the simulation platform, a geometric model of the tunnel entrance approach section is established using 3D modeling tools based on the actual terrain outside the tunnel and the tunnel design data. In the 3D virtual scene, natural light is simulated by a sky sphere, light sources, and skylights. The sky sphere controls the sky type, while the light sources and skylights control the ambient brightness. Tunnel lighting fixtures are simulated by point light sources. The lighting parameters for different sections are modeled according to the design data, and the lighting parameters for different tunnel sections are configured according to the tunnel lighting design data.

[0023] The system is configured with a dynamically adjustable physical light source to simulate varying brightness outside the cave, starting from high brightness and gradually decreasing in increments.

[0024] Specifically, a high-power LED parallel light source with independently controllable output power is used. Starting from 3000 cd / m², the light is adjusted in gradients by decreasing by 1000 cd / m² each time, until the brightness change outside the cave is covered from high brightness at noon on a sunny day to low brightness on a cloudy day.

[0025] The human eye exhibits visual lag; when ambient brightness changes, the pupil requires a certain amount of time to complete the corresponding adjustment response. If the brightness change is too abrupt, the pupil adjustment cannot keep up with the change in light environment, and the measured pupil diameter cannot reflect the visual state under the corresponding brightness conditions. Therefore, by starting with high brightness and gradually adjusting the external brightness in fixed increments, the brightness change is made gradual, giving the driver sufficient adaptation time, ensuring that pupil diameter and reaction time are collected at each brightness gradient.

[0026] At each brightness level, the driver's pupil diameter is synchronously collected by a physiological data acquisition device, and the time required for the driver to detect a randomly appearing visual target in the virtual scene is recorded by a reaction time testing system as the reaction time.

[0027] The specific method for synchronously collecting the driver's pupil diameter using a physiological data acquisition device is as follows: Under each brightness gradient, the driver's pupil is tracked across the entire field of view using a glasses-type eye tracker, recording real-time changes in the driver's pupil diameter. Before data collection, the glasses-type eye tracker is calibrated. During the data collection process, the pupil diameter data is filtered to reduce the impact of blinking and head movements on the data.

[0028] Simultaneously, a reaction time testing system is activated. A light spot emitter with constant brightness randomly appears on the projected video. When the driver notices the light spot, they apply the brakes, and the time required for the driver to notice the light spot is recorded as the reaction time. In the three-dimensional virtual scene, trigger sections with known locations are pre-set along the driving direction of the section approaching the tunnel entrance. The mileage coordinates of each trigger section are pre-calibrated and stored. When the driver's vehicle travels to any trigger section in the virtual scene, a visual target is activated on the roadside at the trigger section. The reaction time testing system starts timing from the moment the visual target is activated.

[0029] Illuminance values ​​at each luminance gradient at the driver's eye position were measured using a lux meter placed at the driver's eye level, and these values ​​were used as ambient light illuminance data.

[0030] By placing the illuminance meter's photosensitive element at the driver's eye level and facing directly forward, the light environment received by the driver's eyes during actual driving can be simulated, making the measured illuminance data spatially correspond to the driver's pupil diameter data.

[0031] As the lighting environment at the tunnel entrance changes from bright to dark, the driver's pupil diameter changes in four stages: outside the tunnel, at the entrance, inside the tunnel, and at the exit. Reaction time follows an S-shaped curve with varying brightness, and it is prolonged at extremely low or high brightness levels. When pupil accommodation cannot keep up with changes in the lighting environment, visual load increases, raising the risk of traffic accidents.

[0032] See Figure 2 As shown, the steps for locating the visual load abrupt change zone are as follows: Within the tunnel entrance approach section, the position where the first adjacent difference in the driver's pupil diameter data changes from the initial fluctuation range to a continuously increasing positive value is marked as the starting point of pupil adjustment. The tunnel entrance approach section refers to a road section extending longitudinally outward from the outer surface of the tunnel entrance for 100 to 300 meters.

[0033] Outside the tunnel, the pupil diameter fluctuates within a narrow range, and the driver's vision is in a comfortable state. After entering the entrance, the pupil begins to dilate continuously to cope with the decrease in ambient brightness. The difference between adjacent pupil diameters changes from the initial fluctuation range to a continuous positive increase, indicating that the driver's pupil has moved out of the normal fluctuation state outside the tunnel and has begun to dilate continuously in response to changes in the light environment.

[0034] The steps for obtaining the initial fluctuation range are as follows: Near the tunnel entrance, collect pupil diameter data from 30 consecutive sampling points. Calculate the difference between the pupil diameters of every two adjacent sampling points to obtain a difference sequence. Calculate the standard deviation of the absolute values ​​of all differences in the difference sequence. Use a multiple of the standard deviation as the upper limit of the initial fluctuation range, and the opposite of the upper limit as the lower limit of the initial fluctuation range. The preset multiple is 3.

[0035] The process for determining a continuous positive increase is as follows: Starting from the end of the segment where the initial fluctuation range is located, calculate the difference between the next and previous pupil diameters at each sampling point along the driving direction. If the difference between 3 to 5 consecutive sampling points is positive and greater than the upper limit of the initial fluctuation range, it is determined that the pupil diameter has entered a positive increase.

[0036] The position where the first adjacent difference in the reaction time data changes from negative to positive is identified as the starting point of the reaction extension.

[0037] The reaction time exhibits an S-shaped trend with changes in external brightness. Within a moderate brightness range, the reaction time decreases as brightness increases, resulting in a negative difference between adjacent values. As brightness continues to rise, it becomes more difficult for the test subject to identify the light spot, and the reaction time changes from shortening to lengthening, with the adjacent difference turning from negative to positive. The turning point indicates that the driver's visual recognition ability begins to decline, and visual load increases; therefore, this is marked as the starting point of the reaction time extension.

[0038] The smaller of the pupillary accommodation start point and the response prolongation start point along the driving direction is taken as the visual load start point.

[0039] As the lighting environment at the tunnel entrance dims, the driver's pupillary accommodation response typically precedes any decline in visual perception. Pupil accommodation is an unconscious physiological reflex with a rapid response; however, a prolonged reaction time involves the brain's judgment and decision-making regarding visual information, resulting in a relatively delayed response. Choosing the smaller of the two coordinates avoids missing the starting point of visual load due to delayed reaction time, ensuring that the earliest abnormal signal is included in the visual load abrupt change segment.

[0040] The position where the first adjacent difference in the driver's pupil diameter data recovers from a continuous positive increase to the initial fluctuation range is marked as the visual adaptation endpoint.

[0041] After the driver's pupil diameter continuously expands during the ascending phase at the entrance, once the pupil has adjusted to the light environment inside the tunnel and enters the tunnel section, the pupil diameter no longer increases but fluctuates stably within a narrow range. The difference between adjacent pupil diameters returns from a continuously increasing positive value to the initial fluctuation range, indicating that the pupil diameter has returned from a state of continuous expansion to a stable fluctuation state. The driver's vision has adapted to the light environment inside the tunnel, and this is therefore marked as the visual adaptation endpoint.

[0042] The segment that starts at the visual load threshold and ends at the visual adaptation threshold is defined as the visual load mutation segment.

[0043] S2. Calculate the illuminance attenuation rate and the driver's pupil area change rate based on the ambient light illuminance data and the driver's pupil diameter, respectively.

[0044] Given that the ambient illuminance at the tunnel entrance and the driver's pupil diameter both vary non-uniformly, the transmittance of the sunshade differs at different locations, and pupil accommodation exhibits a non-linear characteristic of being slow initially, then fast, and then slowing down again, it is necessary to calculate the local rate of change at each sampling interval. Specifically, calculating the illuminance attenuation rate and the driver's pupil area change rate includes: taking the visual load start point and visual adaptation end point as boundaries, dividing the illuminance difference between two adjacent data sampling points within the visual load abrupt change segment by the distance between the two points to obtain the illuminance attenuation rate for each sampling interval.

[0045] The pupil area is calculated by converting the pupil diameter. The difference in pupil area between two adjacent data sampling points within the boundary is divided by the time taken by the driver to pass the distance between the two points, and the driver's pupil area change rate is obtained for each sampling interval.

[0046] The pupil area is calculated based on the pupil diameter using the formula for the area of ​​a circle.

[0047] The time it takes for the driver to traverse the distance between the two points is obtained by dividing the distance between the two points by the average speed of the vehicle between the two points.

[0048] The illuminance attenuation rate at the same sampling interval is spatially correlated with the rate of change in the driver's pupil area.

[0049] Specifically, the mileage coordinates of the first sampling point in each sampling interval are used as the spatial location identifier of that sampling interval. The illuminance attenuation rate and pupil area change rate of that sampling interval are bound to the spatial location identifier one by one to obtain the corresponding data pairs of illuminance attenuation rate and pupil area change rate at each mileage location.

[0050] S3. Determine the pupil matching degree based on the illuminance attenuation rate and the driver's pupil area change rate in the visual load abrupt change section, and determine the mismatched road section based on the pupil matching degree.

[0051] Because the illuminance decreases along the direction of travel in the section approaching the tunnel entrance, while the driver's pupil area increases along the direction of travel, and both trends are synchronized in normal road sections, the determination of pupil matching degree includes: within the section approaching the tunnel entrance, using the remaining road sections outside the visual load abrupt change zone as reference sections, taking the absolute average of all illuminance attenuation rates and the absolute average of all pupil area change rates as reference illuminance attenuation rate and reference pupil area change rate, respectively.

[0052] Using the road sections outside the visual load abrupt change zone as reference sections, the absolute values ​​of their illuminance attenuation rate and pupil area change rate are averaged to represent the normal fluctuation level of the light environment change rate and pupil response rate under normal driving conditions in the section approaching the tunnel entrance. Using this as a reference benchmark, it can be determined whether the change rate within the visual load abrupt change zone is abnormally high.

[0053] Within the visual load abrupt change zone, the spatial range in which the absolute value of the illuminance attenuation rate is greater than the reference illuminance attenuation rate, and the absolute value of the driver's pupil area change rate is greater than the reference pupil area change rate, is judged as having abnormal pupil matching. The vehicle position at each sampling moment is obtained by adding the vehicle position at the previous sampling moment to the product of the average vehicle speed and the sampling period duration within the current sampling period.

[0054] When the absolute value of the illuminance attenuation rate is greater than the reference illuminance attenuation rate, and the absolute value of the pupil area change rate is greater than the reference pupil area change rate, it indicates that the illuminance decrease rate and pupil accommodation rate exceed the normal fluctuation level. This means that the stable relationship between changes in the light environment and the driver's physiological response has been broken, and the visual load borne by the driver has exceeded the normal adaptive capacity, which is an abnormal pupil matching degree.

[0055] Considering that the ambient light intensity decreases continuously along the driving direction as the light environment at the tunnel entrance changes from bright to dark, the driver's pupils need to dilate to increase the amount of light entering and maintain clear vision. Therefore, identifying the mismatched road section includes determining the start and end points of the spatial range where the pupil mismatch is identified as abnormal, respectively, as the start and end points of the mismatched road section. The essence of the mismatched road section is a spatial disconnect between the driver's need for changing light environment and their physiological adjustment ability.

[0056] The spatial range of abnormal pupil matching consists of continuous locations where changes in the light environment and pupil response lose synchronization. Therefore, determining the boundaries of mismatched road sections can accurately define the range of road sections requiring intervention from the perspective of the driver's physiological response.

[0057] S4. Analyze the spatial synergistic relationship between the brightness transition gradient of the shade canopy and the visual guidance intensity of the colored pavement in the mismatched road section to determine the cause of the load change.

[0058] Considering that the driver's pupils dilate to maintain clear vision as the lighting environment at the tunnel entrance changes from bright to dark, the sunshade controls the light transmittance to regulate the light entering the driver's eyes, creating a gradual change in brightness; the colored pavement provides visual guidance signals through color reflection brightness and stripe spacing.

[0059] Based on this, the analysis of the alignment and coordination relationship between the brightness transition gradient of the sunshade and the visual guidance intensity of the colored pavement in the spatial distribution of the mismatched road section includes: obtaining the brightness pseudo-color map of the pavement under each section of the sunshade in the mismatched road section, extracting the location and area ratio of the area directly irradiated by sunlight on the driving lane, and marking the location with the largest change in the area ratio of the directly irradiated area as the brightness change point of the sunshade.

[0060] As a driver moves from outside to inside the sunshade, the change in the percentage of the area directly exposed to sunlight indicates the severity of the sunshade's effect on attenuating sunlight. The location where the percentage of the area directly exposed to sunlight changes the most is the point where the brightness transition of the sunshade is most abrupt, also known as the abrupt change point in the brightness of the sunshade.

[0061] See Figure 3 As shown, the specific steps to obtain the pseudo-color map of the road surface brightness under each section of the sunshade are as follows: First, based on the structural dimensions, hollow height and diffuser placement of the sunshade in the tunnel design drawings, construct a three-dimensional geometric model of the sunshade and import the three-dimensional geometric model into the DIALUX optical simulation software.

[0062] Then, in the DIALUX software, set the transmittance and reflectance of the light-transmitting panels of the shading canopy according to the actual type of diffused light selected, and set the reflectance of the road surface material according to the actual paving type. The reflectance of asphalt pavement is set to 25%.

[0063] Next, input the latitude and longitude coordinates of the project location into the DIALUX software, select the summer solstice, autumnal equinox and winter solstice as the calculation dates, select the time points every hour between 7:30 am and 5:30 pm as the calculation time, set the weather type to sunny, and the DIALUX software will automatically generate the direct sunlight angle and scattering characteristic curves for each calculation time according to the sunlight calculation formula.

[0064] Finally, an illuminance calculation grid was set up in the downhill lane area of ​​the shaded canopy, and ray tracing and light energy transfer were run in DIALUX software to calculate the brightness value of each grid point at each calculation time and generate a brightness pseudo-color map.

[0065] Within the mismatched road section, the color reflectance brightness and stripe spacing of the colored pavement are acquired. The maximum values ​​of reflectance brightness variation and spacing variation are identified. When these two values ​​coincide in space, the point is determined as the peak point of the colored pavement's induction effect. If the maximum values ​​of reflectance brightness variation and spacing variation do not coincide in space, the location corresponding to the larger of the two values ​​is taken as the peak point of the colored pavement's induction effect. This method can separately capture the spatial locations where the color stimulus intensity and spatial induction intensity are most intense, and determine the location where the colored pavement's induction effect is strongest when the two coincide in space, ensuring that the positioning of the colored pavement's visual guidance effect matches the actual situation of the driver's visual perception.

[0066] Colored pavement guides drivers' vision in two ways: it creates visual stimulation through the differences in brightness of the pavement color, guiding the driver's attention; and it creates a sense of speed and direction through the spatial variation of adjacent stripes.

[0067] The specific steps to obtain the color reflectance brightness and stripe spacing of colored pavement are as follows: First, in the mismatched road section, obtain the color type and corresponding material type of each pavement section according to the colored pavement design drawings, and look up the corresponding reflectance brightness value according to the material type.

[0068] Then, the reflectance values ​​of the colored pavement are extracted from the design drawings, and the reflectance values ​​of each location are arranged along the driving direction to form a reflectance sequence; the absolute value of the difference between the reflectance values ​​of adjacent locations is calculated to obtain the color reflectance change sequence.

[0069] Finally, the laying position of each stripe is obtained according to the colored pavement design drawings, the distance between the center lines of two adjacent colored stripes is calculated as the stripe spacing value, and the stripe spacing values ​​at each position are arranged along the driving direction to form a stripe spacing sequence; the absolute value of the difference between the stripe spacings of adjacent positions is calculated to obtain the stripe spacing variation sequence.

[0070] If the brightness abrupt change point of the shade canopy and the peak point induced by the colored pavement are in the same spatial location, then the two are determined to be aligned and coordinated.

[0071] The sunshade creates a brightness transition through changes in light transmittance, alleviating the visual burden on drivers caused by sudden changes in the lighting environment when entering a tunnel. The colored pavement provides visual guidance through changes in color and stripe spacing, directing the driver's attention and adjusting speed. When the brightness transition point of the sunshade and the peak guidance point of the colored pavement are in the same spatial location, the driver receives the strongest visual guidance signal simultaneously at the location of the most drastic brightness change. The two measures work together spatially to create a smooth visual transition zone.

[0072] If the brightness abrupt change point of the shade canopy and the peak point induced by the colored pavement are spatially offset from each other, it is determined that the two are misaligned.

[0073] The abrupt change in brightness at the awning is the point where the brightness transition is most drastic, and it is the point where the driver's visual load is greatest; the peak point of the colored pavement's guidance is the point where the visual guidance effect is strongest. When these two are spatially offset from each other, the driver cannot obtain the strongest visual guidance at the point where the brightness change is most drastic. The visual load and visual guidance lose their spatial correspondence, and the two measures cannot work together to create a visually smooth transition zone.

[0074] Since sunshades reduce visual impact on drivers by controlling light transmittance to create gradual brightness changes, and colored pavements guide drivers' attention and speed through color and stripe arrangement, the process for determining the cause of load change is as follows: when the brightness change point of the sunshade is located before the peak point of the colored pavement's guidance, the load change is determined to be caused by the sunshade's brightness transition preceding the visual guidance of the colored pavement.

[0075] When the abrupt change in brightness of the sunshade occurs before the peak point of the colored pavement's guidance, it indicates that the driver has already experienced the section of road surface brightness change most drastically below the sunshade before reaching the location where the colored pavement's guidance effect is strongest. At this point, the driver has visually perceived the brightness change, but the colored pavement has not yet provided corresponding visual guidance; the two measures are not spatially synchronized. The brightness transition setting of the sunshade is relatively forward, while the visual guidance setting of the colored pavement is relatively lagging.

[0076] When the point of sudden change in the brightness of the sunshade is located after the peak point of the colored pavement, it is determined that the sudden change in load is due to the brightness of the sunshade lagging behind the visual guidance of the colored pavement.

[0077] When the abrupt change in brightness of the sunshade occurs after the peak point of the colored pavement's guidance, it indicates that the driver has already experienced the area with the strongest guiding effect of the colored pavement before reaching the section below the sunshade where the brightness change is most drastic. At this point, the visual guidance signal provided by the colored pavement appears earlier, and the driver receives the guiding stimulus before facing the brightness change, thus prematurely consuming the guiding effect. By the time the driver actually needs visual guidance to cope with the brightness change, the guiding signal has already weakened. The brightness transition setting of the sunshade is relatively delayed, while the visual guidance setting of the colored pavement is relatively advanced.

[0078] S5. Based on the cause of the sudden load change, adjust the length of the sunshade according to the brightness transition gradient of the sunshade and the rate of change of the driver's pupil area, and optimize the color of the colored road surface and the stripe spacing until the pupil matching degree returns to the normal range.

[0079] The method for determining the pupil matching degree returning to the normal range is as follows: After completing the adjustment of the shade canopy length or the optimization of the color and stripe spacing of the colored road surface, the pupil matching degree judgment process is re-executed. If, within the visual load mutation zone, there is no longer a spatial range in which the absolute value of the illuminance attenuation rate is greater than the reference illuminance attenuation rate, and the absolute value of the pupil area change rate is greater than the reference pupil area change rate, then the pupil matching degree is determined to have returned to the normal range. When the cumulative number of executions of the shade canopy length adjustment or the optimization of the color and stripe spacing of the colored road surface reaches a preset maximum iteration threshold, the loop is terminated; the maximum iteration threshold is set to 10 times.

[0080] Considering that the function of the sunshade is to provide brightness transition protection before the driver's pupils have completed adapting to changes in the light environment, adjusting the sunshade length includes: when a sudden change in load causes the sunshade brightness transition setting to lag or advance, within the mismatched road section, acquiring the change in the rate of change of the driver's pupil area along the driving direction, and marking the turning point where the rate of change of the pupil area changes from rising to stabilizing as the pupil adaptation completion point.

[0081] The driver's pupil diameter changes in four stages: outside the cave, at the entrance, inside the cave, and at the exit. During the entrance stage, the pupil continuously dilates to cope with the decreasing ambient brightness, and the pupil area change rate is increasing. During the inside stage, the pupil has completed its adaptation to the cave's light environment, and the pupil area change rate fluctuates within a narrow range. The transition from an increasing to a stable pupil area change rate indicates that the driver's pupil has completed its adaptation to the cave's light environment and entered the cave's internal state; therefore, this turning point is marked as the point of pupil adaptation completion.

[0082] The steps to obtain the change rate of the driver's pupil area along the driving direction are as follows: First, within the mismatched road section, calculate the change rate of the pupil area at each sampling interval starting from the visual load starting point; then, arrange the change rates of the pupil area at each sampling interval along the driving direction according to the mileage coordinates to obtain the change sequence of the change rate of the pupil area along the driving direction.

[0083] The process for judging the increase in pupil area change rate is as follows: Starting from the visual load start point, the pupil area change rate sequence is scanned at sampling intervals along the driving direction; if the pupil area change rate of three consecutive sampling intervals is positive, and the pupil area change rate of the next sampling interval is greater than or equal to the pupil area change rate of the previous sampling interval, then the pupil area change rate is judged to be in an increasing state.

[0084] The process for determining the stability of the pupil area change rate is as follows: After the pupil area change rate is in an upward trend, scanning continues along the driving direction. When the pupil area change rate fluctuates within a preset narrow interval for five consecutive sampling intervals and no longer shows an upward trend, it is determined that the pupil area change rate has changed from rising to stable. The preset narrow interval is centered on the average pupil area change rate of the five consecutive sampling intervals, and its half-width is three times the standard deviation of the pupil area change rate during the upward phase.

[0085] The change in the brightness transition gradient of the awning along the driving direction is obtained. The turning point where the brightness transition gradient first changes from non-zero to zero and then several consecutive brightness transition gradients are zero is marked as the brightness transition completion point.

[0086] If three or more consecutive brightness transition gradients are taken, and all three or more consecutive brightness transition gradients are zero, random noise interference can be eliminated, ensuring that the brightness transition has been stably completed.

[0087] The sunshade canopy controls sunlight transmission in stages through diffusers, and the brightness of the road surface under the canopy gradually decreases as the light transmittance changes. The absolute value of the difference in the proportion of the area directly exposed to sunlight, i.e., the brightness transition gradient, indicates the magnitude of the change in road surface brightness between adjacent cross sections.

[0088] When the brightness transition gradient is non-zero, it indicates that the area of ​​direct sunlight on the road surface below the shade canopy is still changing, and the brightness transition is still in progress. When the brightness transition gradient is continuously zero, it indicates that the area of ​​direct sunlight on the subsequent cross section no longer changes, the brightness of the road surface below the shade canopy has become uniform and stable, the attenuation effect of the shade canopy on sunlight has been basically completed, and the brightness transition has ended.

[0089] The brightness transition gradient is calculated by subtracting the percentage of direct sunlight area of ​​the previous cross-section from the percentage of direct sunlight area of ​​the subsequent cross-section. The absolute value of the difference is taken as the difference in the percentage of direct sunlight area between adjacent cross-sections. The process of obtaining the direct sunlight area of ​​the cross-section is as follows: First, the area of ​​the driving lane below the sunshade is divided into multiple cross-sections along the driving direction, with the cross-sections perpendicular to the driving direction.

[0090] Then, the brightness value of each grid point in the brightness pseudo-color map is compared with the direct sunlight determination threshold. The direct sunlight determination threshold is set to 50% of the average brightness of the external road surface. For example, under the simulated external brightness of 3000 cd / m², the average road surface brightness of the driving lane without a sunshade is 2000 cd / m², so the direct sunlight determination threshold is set to 1000 cd / m².

[0091] The average road surface brightness in the external environment was obtained as follows: In the same simulated scenario without a shade canopy, an illuminance calculation grid was uniformly distributed on the driving lane, and the average road surface brightness of all grid points was calculated.

[0092] Finally, the number of directly sunlit points within each cross-section, and the total number of all grid points within that cross-section, are counted. The percentage of directly sunlit area in that cross-section is obtained by dividing the number of directly sunlit points by the total number of grid points.

[0093] If the pupil adaptation completion point is located after the brightness transition completion point, the length of the light shield is extended; this moves the brightness transition completion point back to coincide with or exceed the pupil adaptation completion point. The length of the light shield is the difference in distance along the driving direction between the pupil adaptation completion point and the brightness transition completion point.

[0094] The purpose of a sunshade is to provide continuous protection against changes in brightness before the driver's pupils have fully adapted to changes in the lighting environment.

[0095] The pupil adaptation completion point signifies that the driver's pupils have completed adjusting to the light environment inside the tunnel and have entered the tunnel; the brightness transition completion point signifies that the attenuation effect of the sunshade on sunlight has ended, and the road surface brightness under the sunshade tends to be uniform and stable. If the pupil adaptation completion point is after the brightness transition completion point, it indicates that the brightness transition of the sunshade has ended prematurely before the driver's pupils have completed adjustment. The driver is still undergoing visual adaptation without the support of the external light environment transition, and the visual load increases sharply. Therefore, the sunshade needs to be extended towards the inside of the tunnel entrance along the driving direction.

[0096] If the pupil adaptation completion point is located before the brightness transition completion point, shorten the length of the light shield; move the brightness transition completion point forward to coincide with the pupil adaptation completion point. The shortening amount is the difference in distance along the driving direction between the brightness transition completion point and the pupil adaptation completion point.

[0097] The pupil adaptation completion point signifies that the driver has completed adjusting to the cave's lighting environment, the pupil area change rate has stabilized, and vision has adapted to the cave's brightness level. The brightness transition completion point signifies that the attenuation effect of the sunshade on sunlight has ended.

[0098] If the pupil adaptation completion point is located before the brightness transition completion point, it indicates that the driver's pupils have already adjusted, but the sunshade is still undergoing a brightness transition. This phase of brightness transition offers no real protection to the driver who has already completed visual adaptation; instead, it increases the construction cost of the sunshade and the tunnel's ventilation resistance. Therefore, the length of the sunshade needs to be shortened, and the brightness transition completion point needs to be moved forward to coincide with the pupil adaptation completion point to avoid redundant design.

[0099] Because dark surfaces absorb more natural light and reflect less, less light enters the driver's eyes, resulting in less stimulation of the pupils. Using darker road surfaces with lower reflectivity in areas with high visual load can reduce the intensity of reflected light stimulation to the pupils, thus alleviating the driver's visual burden. Therefore, optimizing the color and stripe spacing of colored road surfaces includes: when a sudden change in load causes visual induction lag or advance due to the colored road surface, extracting the location of the brightness change point of the sunshade within the mismatched road section as the first spatial location, and the location of the peak point of colored road surface induction as the second spatial location.

[0100] When the visual guidance of colored pavement lags behind or precedes it, it is necessary to quantify the spatial offset between the peak point of guidance and the point of brightness change in order to determine the translation direction and distance of the colored pavement.

[0101] The starting position of the colored pavement is shifted along the driving direction so that the second spatial position coincides with the first spatial position.

[0102] The color in the first spatial position of the colored road surface is replaced with a color scheme with a lower reflectance brightness than the original color, and the color in the position far away from the first spatial position is replaced with a color scheme with a higher reflectance brightness than the original color, thus creating a gradual change in reflectance brightness along the driving direction.

[0103] Specifically, a gradual change in reflectivity is achieved by adjusting the aggregate ratio in the pavement material: In the road segment unit at the first spatial location, an asphalt mixture with a white aggregate volume ratio of 10% and a dark aggregate volume ratio of 90% is used to obtain the lowest reflectivity; in road segment units farther from the first spatial location, the volume ratio of white aggregate is increased and the volume ratio of dark aggregate is decreased unit by unit until both reach 50%, achieving the highest reflectivity. The increment of the white aggregate volume ratio between adjacent road segment units is 10%, and the decrease of the dark aggregate volume ratio is 10%.

[0104] Dark surfaces absorb more natural light and reflect less, resulting in less light entering the driver's eyes and less stimulation to the pupils. Using dark-colored surfaces at the initial spatial location where the brightness change is most concentrated reduces the intensity of reflected light stimulating the pupils and alleviates light stimulation for the driver at the location of maximum visual load. As the driver moves away from this location, the surface gradually transitions to lighter colors with higher reflectivity to avoid secondary visual impact caused by color abrupt changes.

[0105] The stripes of the colored pavement are arranged symmetrically from dense to sparse, centered on the first spatial position.

[0106] The stripe spacing gradually increases from the center position towards both the driving direction and the opposite direction. This increasing spacing between adjacent stripes ensures that each stripe remains distinguishable within the driver's field of vision while driving. Specifically, starting from the center position, the spacing between adjacent stripes gradually increases to both sides by a preset step size.

[0107] The preset step size is calculated based on the driver's eye level and the horizontal distance from the eye level to the nearest line of sight. The angle between the driver's line of sight and each line of sight is calculated. The minimum angle of sight that the human eye can distinguish is used as a constraint to ensure that the difference between the angles of sight of two adjacent lines of sight is not less than the minimum angle of sight that the human eye can distinguish. The value is generally taken as 1.3 to 1.5 minutes. The difference in the distance between two adjacent lines of sight that satisfy the angle constraint is used as the preset step size.

[0108] The calculation process for the angle between the driver's line of sight and each stripe is as follows: Establish a Cartesian coordinate system with the driver's viewpoint's vertical projection on the ground as the origin, the driving direction as the vertical axis, and the horizontal direction perpendicular to the driving direction as the horizontal axis. Obtain the driver's viewpoint height H, and obtain the horizontal distance D from the driver's viewpoint's vertical projection on the ground to the nth stripe. n The driver's eye level H is set at 1.5 meters, and the horizontal distance D is... n Determined based on parking sight distance. The angle β between the driver's line of sight to the nth fringe and the horizontal plane. n Calculate using the following formula: .

[0109] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0110] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0111] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0112] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0113] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A design and analysis method for reducing light at highway tunnel entrances based on driving safety, characterized in that: include: Acquire ambient light data and driver pupil diameter and reaction time in the tunnel entrance approach section of the simulation platform to locate the visual load abrupt change section where the pupil diameter is abnormal and the reaction time increases sharply. The illuminance attenuation rate and the driver's pupil area change rate were calculated based on ambient light illuminance data and driver's pupil diameter, respectively. The pupil matching degree is determined by the illuminance attenuation rate and the driver's pupil area change rate in the visual load abrupt change section, and the mismatched road section is determined based on the pupil matching degree. Analyze the spatial synergistic relationship between the brightness transition gradient of the shade canopy and the visual guidance intensity of the colored pavement in the mismatched road section to determine the cause of the load change. Based on the cause of the sudden load change, the length of the sunshade is adjusted according to the brightness transition gradient of the sunshade and the rate of change of the driver's pupil area, and the color and stripe spacing of the colored road surface are optimized until the pupil matching degree returns to the normal range.

2. The method for light reduction guidance design of highway tunnel entrances based on driving safety as described in claim 1, characterized in that: The acquisition of ambient light intensity data and driver pupil diameter and reaction time data in the tunnel entrance approach section of the simulation platform includes: In the simulation platform, a three-dimensional virtual scene of the section approaching the tunnel entrance is constructed based on the actual terrain outside the tunnel and the tunnel design data, and the real light environment is restored by simulating natural light sources and tunnel lighting fixtures; Configure a dynamically adjustable physical light source to simulate the changing brightness outside the hole, starting from high brightness and adjusting in a gradient with a fixed decreasing amplitude; At each brightness level, the driver's pupil diameter is synchronously collected by a physiological data acquisition device, and the time required for the driver to detect a randomly appearing visual target in the virtual scene is recorded by a reaction time testing system as the reaction time. Illuminance values ​​at each luminance gradient at the driver's eye position were measured using a lux meter placed at the driver's eye level, and these values ​​were used as ambient light illuminance data.

3. The method for design and analysis of light reduction at highway tunnel entrances based on driving safety, as described in claim 1, is characterized in that: The steps for locating the visual load abrupt change segment are as follows: Within the section near the tunnel entrance, the position where the first adjacent difference in the driver's pupil diameter data changes from the initial fluctuation range to a continuously increasing positive value is marked as the starting point of pupil adjustment; The position where the first adjacent difference in the reaction time data changes from negative to positive is marked as the start of the reaction extension. The smaller of the coordinates along the driving direction between the pupillary accommodation initiation point and the response prolongation initiation point is taken as the visual load initiation point; The position where the first adjacent difference in the driver's pupil diameter data recovers from a continuous positive increase to the initial fluctuation range is marked as the visual adaptation endpoint; The segment that starts at the visual load threshold and ends at the visual adaptation threshold is defined as the visual load mutation segment.

4. The method for design and analysis of light reduction at highway tunnel entrances based on driving safety, as described in claim 3, is characterized in that: The calculation of the illuminance attenuation rate and the rate of change in the driver's pupil area includes: Using the visual load start point and visual adaptation end point as boundaries, the illuminance difference between two adjacent data sampling points within the visual load abrupt change segment is divided by the distance between the two points to obtain the illuminance attenuation rate of each sampling interval. The pupil area is calculated based on the pupil diameter. The difference in pupil area between two adjacent data sampling points within the boundary is divided by the time taken by the driver to pass the distance between the two points, and the driver's pupil area change rate is obtained for each sampling interval. The illuminance attenuation rate at the same sampling interval is spatially correlated with the rate of change in the driver's pupil area.

5. The method for design and analysis of light reduction at highway tunnel entrances based on driving safety, as described in claim 1, is characterized in that: The determination of pupil matching degree includes: Within the section near the tunnel entrance, the remaining road sections outside the visual load abrupt change zone are used as reference sections. The absolute values ​​of all illuminance attenuation rates and the absolute values ​​of all pupil area change rates are taken as reference illuminance attenuation rates and reference pupil area change rates, respectively. Within the visual load abrupt change zone, the spatial range in which the absolute value of the illuminance attenuation rate is greater than the reference illuminance attenuation rate, and the absolute value of the driver's pupil area change rate is greater than the reference pupil area change rate, is judged as an abnormal pupil matching degree.

6. The method for design and analysis of light reduction at highway tunnel entrances based on driving safety, as described in claim 5, is characterized in that: The identified mismatched road segments include: The starting and ending points of the spatial range where the pupil matching degree is determined to be abnormal will be identified as the starting and ending points of the mismatched road segment, respectively.

7. The method for design and analysis of light reduction at highway tunnel entrances based on driving safety, as described in claim 1, is characterized in that: The analysis of the spatial synergistic relationship between the brightness transition gradient of the shade canopy and the line-of-sight induction intensity of the colored pavement in the mismatched road section includes: Within the mismatched road section, obtain the brightness pseudo-color map of the road surface under each section of the sunshade, extract the location and area ratio of the area directly exposed to sunlight in the driving lane, and mark the location with the largest change in the area ratio of the directly exposed area as the brightness change point of the sunshade. Within the mismatched road section, the color reflectance brightness and stripe spacing of the colored pavement are obtained. The maximum value of the reflectance brightness change and the maximum value of the spacing change are found. When the two coincide in space, they are determined to be the induced peak point of the colored pavement. If the brightness change point of the shade canopy and the peak point induced by the colored pavement are in the same spatial location, then the two are determined to be aligned and coordinated. If the brightness abrupt change point of the shade canopy and the peak point induced by the colored pavement are spatially offset from each other, it is determined that the two are misaligned.

8. The method for design and analysis of light reduction at highway tunnel entrances based on driving safety, as described in claim 7, is characterized in that: The process for determining the cause of the sudden change in load is as follows: When the point of sudden change in the brightness of the shade canopy is located before the peak point of the colored pavement's induction, it is determined that the sudden change in load is due to the shade canopy's brightness transitioning ahead of the colored pavement's visual induction. When the point of sudden change in the brightness of the sunshade is located after the peak point of the colored pavement, it is determined that the sudden change in load is due to the brightness of the sunshade lagging behind the visual guidance of the colored pavement.

9. The method for design and analysis of light reduction at highway tunnel entrances based on driving safety, as described in claim 8, is characterized in that: The adjustment of the shade canopy length includes: When a sudden change in load causes the brightness setting of the sunshade to be lagging or ahead, the change in the driver's pupil area change rate along the driving direction is obtained in the mismatched road section. The turning point where the pupil area change rate changes from rising to stabilizing is marked as the pupil adaptation completion point. The change of the brightness transition gradient of the awning along the driving direction is obtained. The turning point where the brightness transition gradient first changes from non-zero to zero and then several consecutive brightness transition gradients are zero is marked as the brightness transition completion point. If the pupil adaptation completion point is after the brightness transition completion point, then extend the length of the light shield; If the pupil adaptation completion point is located before the brightness transition completion point, then shorten the length of the shade.

10. The method for design and analysis of light reduction at highway tunnel entrances based on driving safety, as described in claim 8, is characterized in that: The optimized colored pavement color and stripe spacing include: When a sudden change in load causes the visual guidance of the colored pavement to lag or advance, the location of the brightness change point of the shade canopy in the mismatched road section is extracted as the first spatial location, and the location of the peak point of the colored pavement guidance is used as the second spatial location. The starting position of the colored pavement is shifted along the driving direction so that the second spatial position coincides with the first spatial position; The color in the first spatial position of the colored road surface is replaced with a color scheme with a lower reflectance brightness than the original color, and the color in the position far away from the first spatial position is replaced with a color scheme with a higher reflectance brightness than the original color, forming a gradual change in reflectance brightness along the driving direction. The stripes of the colored pavement are arranged symmetrically from dense to sparse, centered on the first spatial position.

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