Tunnel entrance lighting control method and control system

Abstract

The present invention relates to the field of tunnel lighting technology, and in particular to a tunnel entrance lighting control method and control system, comprising: S1, obtaining a first image in a short exposure time mode; obtaining a second image in a long exposure mode; S2, synthesizing the second image and the first image into a high dynamic range image, dividing the image into a low brightness area, a transition area, and a high brightness area; S3, generating a brightness transition curve for the transition area; S4, determining a brightness adjustment curve for the transition area based on the maximum brightness of the tunnel entrance and the rate of change of the pupil area for light and dark adaptation; S5, determining the target brightness of each part of the transition area based on the brightness transition curve and the brightness adjustment curve; S6, adjusting the brightness of the lighting fixtures in the transition area so that the brightness of each part of the transition area reaches the target brightness. The present invention determines the target brightness based on the brightness transition curve combined with the brightness adjustment curve, fully considering the impact of the rate of change of the pupil area for light and dark adaptation on the line of sight, so that the change in brightness at the tunnel entrance is more adapted to the function of the human eye.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel lighting, and in particular to a tunnel entrance lighting control method and control system. Background Art

[0002] Changing lighting conditions at tunnel entrances and exits often cause visual adaptation problems for drivers, manifesting as the "black hole effect" and "white hole effect." The black hole effect refers to the limited field of vision caused by insufficient light when entering a tunnel from bright light, while the white hole effect is the momentary glare caused by excessive light when exiting a dark tunnel. These problems significantly increase the risk of traffic accidents.

[0003] The invention patent application number CN201010286671.0 discloses an automatic control method for tunnel LED lighting based on an intelligent expert illumination curve. This patent detects the brightness outside the tunnel and reduces the brightness value outside the tunnel to obtain the brightness of the transition section inside the tunnel, but cannot accurately obtain the brightness of the transition section.

[0004] The invention patent with application number CN202210114427.9 discloses a tunnel lighting system with adjustable brightness, which detects the brightness values ​​inside and outside the tunnel. When the brightness value L1 outside the tunnel minus the brightness value L2 in the middle of the tunnel is greater than a first threshold, the brightness value of each lighting fixture in the entrance transition section is increased in sequence from the exit to the entrance, so that the brightness value of each lighting fixture in the entrance transition section increases one by one along the direction from the exit to the entrance; the brightness value of each lighting fixture in the exit transition section is increased in sequence from the entrance to the exit, so that the brightness value of each lighting fixture in the exit transition section increases one by one along the direction from the entrance to the exit.

[0005] When the value of the brightness outside the tunnel entrance (L1) minus the value of the brightness in the middle of the tunnel (L2) is less than the second threshold, the brightness of each lighting fixture in the entrance transition section is sequentially reduced from the exit to the entrance, so that the brightness of each lighting fixture in the entrance transition section decreases from the exit to the entrance. Similarly, the brightness of each lighting fixture in the exit transition section is sequentially reduced from the entrance to the exit, so that the brightness of each lighting fixture in the exit transition section decreases from the entrance to the exit. This technology does not provide a method for determining the target brightness of the transition zone, making it difficult to optimize the brightness value in the transition zone.

[0006] The invention patent with application number CN202010196481.3 discloses a method for eliminating the black hole phenomenon at the entrance of a tunnel. Brightness sensors are installed inside and outside the tunnel. The brightness inside and outside the tunnel is collected in real time through the brightness sensors to calculate the dark adaptation characteristic curve of the human eye. The lighting brightness of the visual transition section is dynamically and smoothly adjusted according to the dark adaptation characteristic curve of the human eye to eliminate the black hole phenomenon that occurs in the human eye when a vehicle enters the tunnel. Its dark adaptation characteristic curve is determined only by the brightness of the tunnel entrance and the time the vehicle enters the tunnel. It does not take into account the rate of change of the pupil area for light and dark adaptation. The rate of change of the pupil area for light and dark adaptation refers to the rate at which the pupil area changes over time when the eye adapts from a bright environment to a dark environment, or from a dark environment to a bright environment. The generated human eye adaptation characteristic curve is not reasonable enough. In addition, it is necessary to detect the time when the vehicle enters the tunnel, which results in errors. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a tunnel entrance lighting control method and control system, which can more reasonably adjust the tunnel entrance lighting brightness, so that the driver's eyes can better adapt to the brightness changes at the tunnel entrance and exit, thereby improving driving safety.

[0008] To solve the above problems, the present invention adopts a technical solution: a tunnel entrance lighting control method, comprising:

[0009] S1. In a short exposure time mode, an image of the interior of the tunnel entrance is captured to obtain a first image; in a long exposure time mode, an image of the interior of the tunnel entrance is captured to obtain a second image. The second image and the first image have the same area, including a low-brightness area, a transition area, and a high-brightness area.

[0010] S2. Combining the second image and the first image into a high dynamic range image, analyzing the brightness distribution in the high dynamic range image, and dividing it into a low brightness area, a transition area, and a high brightness area;

[0011] S3, generating a brightness transition curve for the transition zone;

[0012] S4. Determine a brightness adjustment curve for the transition zone based on the maximum brightness at the tunnel entrance and the rate of change of the pupil area adapted to light and dark;

[0013] S5. Determine the target brightness of each part of the transition area according to the brightness transition curve and the brightness adjustment curve;

[0014] S6. Adjust the brightness of the lighting fixtures in the transition zone so that the brightness of each part of the transition zone reaches the target brightness.

[0015] Furthermore, in step S2, the process of synthesizing the second image and the first image into a high dynamic range image includes:

[0016] Image alignment: perform feature matching on the second image and the first image, and align the pixel data at the same position in the second image and the first image;

[0017] Image fusion: Assign different weights to each pixel based on the exposure value of the image area, giving higher weights to the bright areas of the short-exposure image and higher weights to the dark areas of the long-exposure image;

[0018] Tone mapping: Compresses the brightness of highlight and shadow areas in an image to the range that the display device can present, while enhancing the contrast of the image to maintain the visual effect of the image.

[0019] Furthermore, in step S2,

[0020] The central difference method is used to calculate the brightness difference between the two adjacent sampling points before and after, and the illumination change rate m is obtained. The calculation formula is:

[0021]

[0022] Where x i is the sampling point at position i, x i-1 and x i+1 are the two sampling points adjacent to position i, I(x i-1 ) is the sampling point x i-1 The brightness at I(x i+1 ) is the sampling point x i+1 The brightness at x i+1 -x i-1 is the distance between two sampling points;

[0023] At the end facing the interior of the tunnel, the sampling point where the m value is equal to the first threshold or the difference between the m value and the first threshold is the smallest is taken as the inner endpoint; at the end facing the tunnel entrance, the sampling point where the m value is equal to the second threshold or the difference between the m value and the second threshold is the smallest is taken as the outer endpoint, and the area between the inner and outer endpoints is taken as the transition zone.

[0024] Furthermore, in step S3, the brightness transition curve is y(x)=b+a(x i -x0), where y(x) is the target brightness at position i, b is the inner endpoint brightness, a is the coefficient, x0 is the inner endpoint position, and x i -x0 is the distance from position i to the inner endpoint;

[0025] The process of determining the a value is as follows: according to the brightness data of the transition area (x1, I1), (x2, I2), ..., (x n ,I n ), solve the error function by the least squares method and optimize the parameter a of the linear function.

[0026] Furthermore, in step S4, the brightness adjustment curve is

[0027]

[0028] Among them, L(x) is the target brightness at position x, A is the maximum brightness value at the tunnel entrance, σ(v e ) is the pupil area change rate v according to light and dark adaptation e Dynamically adjusted transition width, μ is the center position of the transition area, and x-μ is the distance from position x to position μ.

[0029] Furthermore, in step S5, a first target brightness is calculated according to the brightness transition curve, a second target brightness is calculated according to the brightness adjustment curve, and an average value of the first target brightness and the second target brightness is used as the final target brightness.

[0030] The control system used in the above tunnel entrance lighting control method includes:

[0031] A plurality of lamps arranged in the tunnel for illuminating the interior of the tunnel;

[0032] The image acquisition component is used to acquire an image of the interior of the tunnel entrance in a short exposure time mode to obtain a first image; and to acquire an image of the interior of the tunnel entrance in a long exposure time mode to obtain a second image, wherein the second image and the first image have the same area, including a low brightness area, a transition area, and a high brightness area;

[0033] Brightness monitoring element, used to obtain the maximum brightness of the tunnel entrance;

[0034] Processing systems for performing the following processes:

[0035] synthesizing the second image and the first image into a high dynamic range image, analyzing the brightness distribution in the high dynamic range image, and dividing the image into a low brightness area, a transition area, and a high brightness area;

[0036] Generate a brightness transition curve for the transition area;

[0037] The brightness adjustment curve of the transition zone is determined according to the maximum brightness of the tunnel entrance and the rate of change of pupil area adapted to light and dark;

[0038] Determine the target brightness of each part of the transition zone according to the brightness transition curve and the brightness adjustment curve;

[0039] Adjust the brightness of the lighting fixtures in the transition zone so that the brightness of each part of the transition zone reaches the target brightness.

[0040] Furthermore, the image acquisition element includes a high dynamic range imaging module, which includes a pixel array and an imaging circuit. The pixel array includes multiple first sub-pixels and multiple second sub-pixels. The first sub-pixels generate electrical signals based on the received bright area light, and the second sub-pixels generate electrical signals based on the received dark area light; the imaging circuit generates the first image and the second image based on the electrical signals generated by the first sub-pixels and the second sub-pixels.

[0041] The beneficial effects of the present invention are: 1. By acquiring the brightness data inside the tunnel entrance through high dynamic range imaging technology, the light distribution at the tunnel entrance and exit can be captured accurately in real time, with better image quality and higher contrast, and it can adapt to complex lighting environments, reduce the post-data processing process, and ensure accurate and timely brightness adjustment.

[0042] 2. The present invention determines the target brightness based on a brightness transition curve combined with a brightness adjustment curve, fully considering the impact of the pupil area change rate of light and dark adaptation on vision. This makes the change in tunnel entrance brightness more adaptable to the function of the human eye. When entering and exiting the tunnel, the driver's eyes are more comfortable, and the "black hole effect" and "white hole effect" can be better eliminated. The driver can see the road conditions ahead clearly, which is conducive to ensuring driving safety at the tunnel entrance. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a flow chart of the tunnel entrance lighting control method of the present invention;

[0044] Figure 2 It is a schematic diagram of the control system of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be further described below with reference to the accompanying drawings and examples.

[0046] The tunnel entrance lighting control method of the present invention comprises:

[0047] S1. In short exposure time mode, capture an image of the interior of the tunnel entrance to obtain a first image; in long exposure time mode, capture an image of the interior of the tunnel entrance to obtain a second image. The second image and the first image have the same area, including a low-brightness area, a transition area, and a high-brightness area.

[0048] Existing technologies often use light sensors for brightness monitoring. However, light sensors can only detect the brightness at the sensor's location and cannot monitor the brightness of all points within a certain area. Therefore, a large number of light sensors must be installed, which is costly and has a small monitoring range. In addition, light sensors have a certain response delay, which prevents the system from adjusting the light brightness in a timely manner. In the present invention, the brightness distribution of the interior area of ​​the tunnel entrance is obtained by collecting and analyzing images. The image acquisition element can have a wider shooting range, so only one or two image acquisition elements need to be installed at the tunnel entrance to meet the brightness monitoring requirements, saving implementation costs.

[0049] Specifically, when capturing images, in areas with stronger light (i.e., bright areas), short exposure can clearly capture more details and improve the usability of the image; in areas with weaker light (i.e., dark areas), increasing the exposure time can capture more details and avoid loss of details in dark areas or images being too dark.

[0050] The short exposure shooting and the long exposure shooting are performed successively by the same image acquisition component to obtain the first image and the second image successively. The same image acquisition component can ensure that the shooting areas are exactly the same.

[0051] S2. Combining the second image and the first image into a high dynamic range image, analyzing the brightness distribution in the high dynamic range image, and dividing it into a low brightness area, a transition area, and a high brightness area.

[0052] The second image and the first image acquired by the image acquisition element are low dynamic range images. After the second image and the first image are synthesized into a high dynamic range image, the details of the dark and bright areas on the image are more prominent, and the brightness distribution can be displayed more intuitively.

[0053] The specific process of synthesizing the second image and the first image into a high dynamic range image includes:

[0054] Image alignment: During the synthesis process, the two images with different exposures need to be aligned. Using image registration methods, the second image is feature-matched with the first, ensuring accurate alignment of pixel data at the same location in the second and first images. Since the second and first images capture the exact same area, the two images can be perfectly aligned.

[0055] Image fusion: Assigns different weights to each pixel based on the exposure value of the image area, giving higher weights to the bright areas of the short-exposure image and higher weights to the dark areas of the long-exposure image.

[0056] Tone mapping: Compresses the brightness of highlight and shadow areas in an image to the range that the display device can present, while enhancing the contrast of the image to maintain the visual effect of the image.

[0057] Finally, output the image.

[0058] In a high dynamic range image, the brightness value of each pixel can be extracted to obtain the brightness value of each point in the shooting area.

[0059] The low brightness zone is the area inside the tunnel with low brightness and relatively stable brightness; the high brightness zone is the area close to the tunnel entrance with high brightness and relatively stable brightness; the transition zone is the area between the low brightness zone and the high brightness zone, where the brightness transitions from low brightness in the tunnel to high brightness, and it is also the area where the brightness needs to be adjusted to prevent the occurrence of "black hole effect" and "white hole effect".

[0060] Specifically, the division process of low brightness area, transition area and high brightness area is as follows:

[0061] According to the brightness distribution of each area on the high dynamic range image, the central difference method is used to calculate the brightness difference between the two adjacent sampling points to obtain the illumination change rate m. The calculation formula is:

[0062]

[0063] Where x i is the sampling point at position i, x i-1 and x i+1 are the two sampling points adjacent to position i, I(x i-1 ) is the sampling point x i-1 The brightness at I(x i+1 ) is the sampling point x i+1 The brightness at x i+1 -x i-1 is the distance between two sampling points.

[0064] Along the length of the tunnel, multiple evenly distributed sampling points are selected from the high dynamic range image, and the illumination change rate m between the sampling points is calculated. The illumination change rate m is the rate of change in brightness. When the value of m is close to or equal to the first or second threshold, the brightness is relatively stable, the rate of change is small, and the brightness change does not affect human vision, so brightness adjustment is not required. When the value of m is greater than the first or second threshold, the brightness change rate is large, and the brightness change curve needs to be controlled to enable the human eye to better adapt to brightness changes. Therefore, at the end facing the tunnel interior, the sampling point with an m value equal to the first threshold or with the smallest difference between the m value and the first threshold is used as the inner endpoint; at the end facing the tunnel entrance, the sampling point with an m value equal to the second threshold or with the smallest difference between the m value and the second threshold is used as the outer endpoint. The area between the inner and outer endpoints is used as the transition zone. The first and second thresholds can be flexibly set according to actual needs.

[0065] S3. Generate a brightness transition curve for the transition zone.

[0066] The straight line is used as the brightness transition curve, and the brightness transition curve is expressed as y(x)=b+a(x i -x0), where y(x) is the target brightness at position i, b is the inner endpoint brightness, a is the coefficient, x0 is the inner endpoint position, and x i -x0 is the distance from position i to the inner endpoint. Among them, the coefficient a is an important parameter.

[0067] The process of determining the a value is as follows: according to the brightness data of the transition area (x1, I1), (x2, I2), ..., (x n ,I n ), solve the error function by the least square method and optimize the parameter a of the linear function, (x n ,I n ) represents the position x n Brightness I n .

[0068] By generating a brightness transition curve based on actual lighting data and the lighting change rate m, it is possible to ensure a smooth and natural lighting transition when entering a tunnel from strong external light, optimize the driver's visual adaptation process, and avoid the discomfort caused by abrupt brightness changes.

[0069] S4. Determine a brightness adjustment curve for the transition zone based on the maximum brightness at the tunnel entrance and the rate of change of the pupil area adapted to light and dark.

[0070] Specifically, the brightness adjustment curve is

[0071]

[0072] Among them, L(x) is the target brightness at position x, A is the maximum brightness value at the tunnel entrance, σ(v e ) is the pupil area change rate v according to light and dark adaptation e Dynamically adjusted transition width, μ is the center position of the transition area, and x-μ is the distance from position x to position μ.

[0073] σ(v e ) is calculated by the following formula:

[0074] σ(ve)=k×|v e | -β

[0075] Among them, v e represents the rate of change of pupil area during light-dark adaptation. k and β are coefficients obtained through experimental fitting. Based on literature analysis and research, k was set to 10 and β to 0.5, which was then used to calculate the light-dark adaptation transition width.

[0076] The maximum brightness value A at the tunnel entrance is related to the brightness outside the tunnel. A light sensor can be set at the end face of the tunnel, and the brightness value detected by the light sensor is the maximum brightness value A at the tunnel entrance.

[0077] The pupil area change rate of light-dark adaptation includes the pupil area change rate of light-adaptation and the pupil area change rate of dark-adaptation. When entering the tunnel, the pupil area change rate of dark-adaptation is used. At this time, v e 1mm 2 / s; when leaving the tunnel, the pupil area change rate of light adaptation is adopted, at this time v e -3mm 2 / s.

[0078] S5. Determine the target brightness of each part of the transition area according to the brightness transition curve and the brightness adjustment curve.

[0079] The first target brightness of each sampling point is calculated according to the brightness transition curve, the second target brightness of each sampling point is calculated according to the brightness adjustment curve, and the average of the first target brightness and the second target brightness is used as the final target brightness.

[0080] The brightness transition curve ensures a smooth transition within the transition zone, avoiding abrupt brightness changes. The brightness adjustment curve takes into account changes in pupil area due to light and dark adaptation, determining the optimal brightness change pattern that the human eye can adapt to when entering and exiting a tunnel. Combining the brightness transition curve with the brightness adjustment curve ensures that the final target brightness approximates both the brightness transition curve and the brightness adjustment curve. This ensures smooth brightness changes within the transition zone, adapting to changes in the human eye and ensuring good visibility for the driver, improving safety.

[0081] S6. Adjust the brightness of the lighting fixtures in the transition zone so that the brightness of each part of the transition zone reaches the final target brightness.

[0082] The tunnel entrance lighting control system of the present invention is as follows: Figure 2 Shown, including

[0083] Multiple lamps are installed in the tunnel, which can use LED lamps to illuminate the interior of the tunnel;

[0084] The image acquisition component is used to acquire an image of the interior of the tunnel entrance in a short exposure time mode to obtain a first image; and to acquire an image of the interior of the tunnel entrance in a long exposure time mode to obtain a second image, wherein the second image and the first image have the same area, including a low brightness area, a transition area, and a high brightness area;

[0085] Brightness monitoring element, used to obtain the maximum brightness of the tunnel entrance;

[0086] Processing systems for performing the following processes:

[0087] synthesizing the second image and the first image into a high dynamic range image, analyzing the brightness distribution in the high dynamic range image, and dividing the image into a low brightness area, a transition area, and a high brightness area;

[0088] Generate a brightness transition curve for the transition area;

[0089] The brightness adjustment curve of the transition zone is determined according to the maximum brightness of the tunnel entrance and the rate of change of pupil area adapted to light and dark;

[0090] Determine the target brightness of each part of the transition zone according to the brightness transition curve and the brightness adjustment curve;

[0091] Adjust the brightness of the lighting fixtures in the transition zone so that the brightness of each part of the transition zone reaches the target brightness.

[0092] Among them, the image acquisition element includes a high dynamic range (HDRI) imaging module, the high dynamic range imaging module includes a pixel array and an imaging circuit, the pixel array includes multiple first sub-pixels and multiple second sub-pixels, the first sub-pixels generate electrical signals based on the received bright area light, and the second sub-pixels generate electrical signals based on the received dark area light; the imaging circuit generates the first image and the second image based on the electrical signals generated by the first sub-pixels and the second sub-pixels.

[0093] Using the HDRI imaging module provides the following advantages:

[0094] 1. Enhanced brightness capture: Through pixel-level exposure control, details in both bright and dark areas are preserved, avoiding the overexposure or underexposure problems that occur in high-contrast scenes with ordinary cameras.

[0095] 2. Improve shooting efficiency: HDRI uses a single shot to obtain complete brightness information, rather than the multiple exposures of traditional HDR solutions, reducing shooting delays and improving image alignment accuracy.

[0096] 3. Adapt to the complex lighting environment of the tunnel: The contrast range is wider, which can accurately reflect the brightness distribution of the tunnel entrance and exit, and improve the intelligent adjustment capability of the lighting system.

[0097] 4. Reduce computational burden: The HDRI module directly generates the required short-exposure images and long-exposure images without the need for complex post-image synthesis processing, thereby improving the real-time performance of the system.

[0098] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A tunnel entrance lighting control method, characterized in that: include: S1. In short exposure time mode, capture an image of the interior of the tunnel entrance to obtain a first image; In the long exposure mode, an image of the interior of the tunnel entrance is captured to obtain a second image. The second image has the same area as the first image, including a low-brightness area, a transition area, and a high-brightness area. S2. Combining the second image and the first image into a high dynamic range image, analyzing the brightness distribution in the high dynamic range image, and dividing it into a low brightness area, a transition area, and a high brightness area; S3. Generate a brightness transition curve for the transition zone: Take a straight line as the brightness transition curve, and the brightness transition curve is expressed as y(x)=b+a(x i -x0), where y(x) is the target brightness at position i, b is the inner endpoint brightness, a is the coefficient, x0 is the inner endpoint position, and x i -x0 is the distance from position i to the inner endpoint; The process of determining the a value is as follows: according to the brightness data of the transition area (x1, I1), (x2, I2), ..., (x n ,I n ), solve the error function by the least square method and optimize the parameter a of the linear function, (x n ,I n ) represents the position x n Brightness I n ; S4. Determine the brightness adjustment curve of the transition zone based on the maximum brightness of the tunnel entrance and the rate of change of the pupil area adapted to light and dark: the brightness adjustment curve is Among them, L(x) is the target brightness at position x, A is the maximum brightness value at the tunnel entrance, σ(v e ) is the pupil area change rate v according to light and dark adaptation e Dynamically adjusted transition width, μ is the center position of the transition zone, and x-μ is the distance from position x to position μ; σ(v e ) is calculated by the following formula: σ(v e )=k×|v e | -β Among them, v e represents the rate of change of pupil area due to light-dark adaptation; k and β are coefficients, k is proposed to be 10 and β is 0.5; The maximum brightness value A at the tunnel entrance is related to the brightness outside the tunnel. A light sensor is set at the end face of the tunnel, and the brightness value detected by the light sensor is the maximum brightness value A at the tunnel entrance; The pupil area change rate of light-dark adaptation includes the pupil area change rate of light-adaptation and the pupil area change rate of dark-adaptation. When entering the tunnel, the pupil area change rate of dark-adaptation is used. At this time, v e 1mm 2 / s; when leaving the tunnel, the pupil area change rate of light adaptation is adopted, at this time v e -3mm 2 / s; S5. Determine the target brightness of each part of the transition area according to the brightness transition curve and the brightness adjustment curve; S6. Adjust the brightness of the lighting fixtures in the transition zone so that the brightness of each part of the transition zone reaches the target brightness.

2. The tunnel entrance lighting control method according to claim 1, characterized in that: In step S2, the process of synthesizing the second image and the first image into a high dynamic range image includes: Image alignment: perform feature matching on the second image and the first image, and align the pixel data at the same position in the second image and the first image; Image fusion: Assign different weights to each pixel based on the exposure value of the image area, giving higher weights to the bright areas of the short-exposure image and higher weights to the dark areas of the long-exposure image; Tone mapping: Compresses the brightness of highlight and shadow areas in an image to the range that the display device can present, while enhancing the contrast of the image to maintain the visual effect of the image.

3. The tunnel entrance lighting control method according to claim 1, characterized in that: In step S2, The central difference method is used to calculate the brightness difference between the two adjacent sampling points before and after, and the illumination change rate m is obtained. The calculation formula is: Where x i is the sampling point at position i, x i-1 and x i+1 are the two sampling points adjacent to position i, I(x i-1 ) is the sampling point x i-1 The brightness at I(x i+1 ) is the sampling point x i+1 The brightness at x i+1 -x i-1 is the distance between two sampling points; At the end facing the interior of the tunnel, the sampling point where the m value is equal to the first threshold or the difference between the m value and the first threshold is the smallest is taken as the inner endpoint; At the end facing the tunnel entrance, the sampling point where the m value is equal to the second threshold or the difference between the m value and the second threshold is the smallest is taken as the outer endpoint, and the area between the inner endpoint and the outer endpoint is taken as the transition area.

4. The tunnel entrance lighting control method according to claim 1, wherein: In step S5, the first target brightness is calculated according to the brightness transition curve, the second target brightness is calculated according to the brightness adjustment curve, and the average of the first target brightness and the second target brightness is used as the final target brightness.

5. A control system for the tunnel entrance lighting control method according to any one of claims 1 to 4, characterized in that: include A plurality of lamps arranged in the tunnel for illuminating the interior of the tunnel; An image acquisition component is used to acquire an image of the interior of the tunnel entrance in a short exposure time mode to obtain a first image; In the long exposure mode, an image of the interior of the tunnel entrance is captured to obtain a second image. The second image has the same area as the first image, including a low-brightness area, a transition area, and a high-brightness area. Brightness monitoring element, used to obtain the maximum brightness of the tunnel entrance; Processing systems for performing the following processes: synthesizing the second image and the first image into a high dynamic range image, analyzing the brightness distribution in the high dynamic range image, and dividing the image into a low brightness area, a transition area, and a high brightness area; Generate a brightness transition curve for the transition area; The brightness adjustment curve of the transition zone is determined according to the maximum brightness of the tunnel entrance and the rate of change of pupil area adapted to light and dark; Determine the target brightness of each part of the transition zone according to the brightness transition curve and the brightness adjustment curve; Adjust the brightness of the lighting fixtures in the transition zone so that the brightness of each part of the transition zone reaches the target brightness.

6. The control system according to claim 5, characterized in that The image acquisition element includes a high dynamic range imaging module, which includes a pixel array and an imaging circuit. The pixel array includes multiple first sub-pixels and multiple second sub-pixels. The first sub-pixels generate electrical signals based on received bright area light, and the second sub-pixels generate electrical signals based on received dark area light. The imaging circuit generates a first image and a second image based on the electrical signals generated by the first sub-pixels and the second sub-pixels.

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