A lighting method and lighting device for a laser vehicle light

Abstract

The application provides a laser vehicle lamp lighting method and a lighting device, and the method comprises the following steps: controlling a laser vehicle lamp at the front end of a vehicle to emit a laser beam to irradiate a driving road surface in front of the vehicle; receiving a reflected light signal of the driving road surface, determining a polarization rotation angle and an extinction ratio of the laser beam according to the reflected light signal of the driving road surface, and the extinction ratio reflects the degree of depolarization of the driving road surface on the laser beam; comparing the polarization rotation angle and the extinction ratio with a preset template to determine a road surface state type of the driving road surface in front of the vehicle, and adjusting a lighting mode of the laser vehicle lamp according to the road surface state type, so that the adjustment of the lighting mode is accurately matched with the actual optical response characteristics of the road surface material, the adverse optical effects are effectively inhibited, and the driving safety hidden danger is avoided.

Description

Technical Field

[0001] This invention relates to the field of vehicle lighting technology, and more particularly to a laser vehicle lighting method and lighting device. Background Technology

[0002] Laser headlights feature high energy density and excellent collimation, enabling long-distance illumination that is twice the distance of LED light sources. They are also more energy efficient and can significantly improve visibility on unlit roads at night.

[0003] Existing laser vehicle lights generally use fixed lighting methods. However, in actual traffic environments, road surfaces include various material states such as dry asphalt, wet water, snow and ice, and gravel. The microscopic surface structures of different materials have fundamentally different polarization modulation characteristics of the laser beam, resulting in a mismatch between the energy distribution of the laser beam and the optical characteristics of the road surface. This leads to strong specular reflections on icy and snowy roads causing driver glare, light curtain interference on waterlogged roads, and light dispersion and loss on gravel roads, among other lighting failures. Moreover, these lighting failures are particularly prominent under complex weather and road conditions, which can easily cause driving safety hazards. Summary of the Invention

[0004] This invention provides a method and device for laser vehicle lighting, which achieves precise matching between the lighting mode adjustment and the actual optical characteristics of the road surface material, effectively suppressing adverse optical effects and avoiding driving safety hazards.

[0005] To solve the above problems, the present invention adopts the following technical solution: This invention provides a method for illuminating a laser vehicle headlight, comprising: Control the laser headlights at the front of the vehicle to emit laser beams to illuminate the road surface in front of the vehicle; The system receives the reflected light signal from the road surface and determines the polarization rotation angle and extinction ratio of the laser beam based on the reflected light signal from the road surface. The extinction ratio reflects the degree of depolarization of the laser beam by the material of the road surface. The polarization rotation angle and extinction ratio are compared with a preset template to determine the road surface condition type of the road surface in front of the vehicle. The illumination mode of the laser headlights is adjusted according to the road surface condition type.

[0006] Preferably, the laser beam is polarized by a polarizer and emitted as linearly polarized light. After illuminating the road surface, it is reflected, and the angle between the polarization direction of the reflected light and the initial polarization direction of the emitted light is the polarization rotation angle.

[0007] Preferably, the laser beam is polarized by a polarizer and emitted as linearly polarized light. After illuminating the road surface, it is reflected. When the reflected light passes through the analyzer, the analyzer is rotated to the position of the maximum light intensity received by the photodetector and the first light intensity value is recorded. Then the analyzer is rotated to the position of the minimum light intensity and the second light intensity value is recorded. The ratio of the first light intensity value to the second light intensity value is the extinction ratio.

[0008] Preferably, the road surface condition type includes the material type and humidity level information of the road surface.

[0009] Furthermore, adjusting the illumination mode of the laser vehicle headlights according to the road surface condition type includes: When the road surface condition is wet asphalt road surface, reduce the illumination intensity of the laser headlights and increase the divergence angle of the laser beam to a preset value; When the road surface condition is a waterlogged road surface, the blue laser of the laser headlight is turned off, and the lateral scanning angle of the red and green lights is increased to form a fan-shaped light curtain; When the road surface condition is dry and rough, the laser headlights are adjusted to the standard lighting mode, and the power of the laser headlights is increased to the standard value.

[0010] Further, the step of comparing the polarization rotation angle and extinction ratio with a preset template to determine the road surface condition type of the road surface in front of the vehicle includes: The polarization rotation angle is converted into a first voltage signal, and the extinction ratio is converted into a second voltage signal; The first voltage signal and the second voltage signal are respectively input to the first input terminal and the second input terminal of the parallel comparison array. The parallel comparison array includes multiple comparison units. Each comparison unit stores a reference voltage pair corresponding to a preset template. Each reference voltage pair includes a third voltage signal and a fourth voltage signal. Each comparison unit compares the voltage amplitude of the first voltage signal with the third voltage signal, and compares the voltage amplitude of the second voltage signal with the fourth voltage signal. When the amplitude difference between the first voltage signal and the third voltage signal is less than the amplitude difference between the second voltage signal and the fourth voltage signal, the comparison unit outputs a first level; otherwise, it outputs a second level. The output terminals of all comparison units are connected to the judgment unit. The judgment unit allows only the highest priority first level to pass through at any time, blocks the second level and other priority first levels, and encodes the passed first level as the road surface state type.

[0011] Preferably, the number of comparison units in the parallel comparison array is equal to the number of road surface state types, and each comparison unit corresponds to a unique preset template.

[0012] Further, determining the polarization rotation angle and extinction ratio of the laser beam based on the reflected light signal from the road surface includes: The reflected light signal is photoelectrically converted to generate an electrical signal sequence; The electrical signal sequence is digitally sampled to obtain the original data stream; The original data stream is time-aligned and reconstructed, and Stokes vector components are extracted from the reconstructed waveform data. The polarization rotation angle and extinction ratio are calculated based on the Stokes vector components. The Stokes vector components include the phase offset and amplitude value of the waveform data.

[0013] Further, the step of performing time-series alignment and waveform reconstruction on the original data stream, extracting Stokes vector components from the reconstructed waveform data, and calculating the polarization rotation angle and extinction ratio based on the Stokes vector components includes: Based on the original data stream, a sequence of emission time markers for the laser beam is constructed, and each emission time marker is paired with its corresponding reception time marker to obtain a marker pair; Calculate the time delay value between the tag pairs, remove abnormal tag pairs whose time delay values ​​exceed a preset range, and perform interpolation on the retained tag pairs to obtain waveform data; The waveform data is divided into multiple waveform windows, each of which includes a complete pulse cycle; The phase offset of the waveform data within each waveform window is extracted, and the phase offset is converted into an angle offset to obtain multiple initial polarization rotation angles; Extract the maximum and minimum amplitude values ​​of the waveform data within each waveform window, calculate the ratio of the maximum amplitude value to the minimum amplitude value, and obtain multiple initial extinction ratio values; The initial polarization rotation angles calculated from multiple consecutive waveform windows are combined into an angle sequence, and the angle sequence is filtered by moving average to obtain the polarization rotation angle. The initial extinction ratio values ​​calculated from multiple consecutive waveform windows are combined into an extinction ratio sequence. The extinction ratio sequence is then subjected to median filtering to obtain the extinction ratio value.

[0014] The present invention also provides a lighting device for laser vehicle lights, comprising: The transmitting module is used to control the laser headlights at the front of the vehicle to emit laser beams to illuminate the road surface in front of the vehicle. The receiving module is used to receive the reflected light signal from the road surface and determine the polarization rotation angle and extinction ratio of the laser beam based on the reflected light signal from the road surface. The extinction ratio reflects the degree of depolarization of the laser beam by the material of the road surface. The determination module is used to compare the polarization rotation angle and extinction ratio with a preset template to determine the road surface condition type of the road surface in front of the vehicle. An adjustment module is used to adjust the lighting mode of the laser vehicle lights according to the road surface condition type.

[0015] Compared with the prior art, the technical solution of the present invention has at least the following advantages: This invention provides a laser vehicle headlight illumination method and device. By emitting a laser beam to actively illuminate the road surface and receiving the reflected light signal, the polarization rotation angle and extinction ratio are directly determined. This transforms the microscopic depolarization characteristics of the road surface material into quantifiable optical parameters. After comparing these parameters with a preset template, the road surface condition type is determined, and the illumination mode of the laser vehicle headlight is adjusted accordingly. This establishes a direct mapping relationship from the polarization modulation characteristics of the road surface material to illumination control, enabling the perception and feedback of the optical characteristics of the road surface material. This allows for precise matching of the illumination mode adjustment with the actual optical response characteristics of the road surface material, effectively suppressing adverse optical effects, improving illumination effectiveness, and avoiding driving safety hazards for drivers. Attached Figure Description

[0016] Figure 1 This is a flowchart of one embodiment of a laser vehicle lighting method according to the present invention; Figure 2 This is a flowchart illustrating another embodiment of a laser vehicle lighting method according to the present invention; Figure 3 This is a structural block diagram of one embodiment of a laser vehicle lighting device according to the present invention. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0018] Current solutions to adaptable road lighting typically focus on intensity sensing, color recognition, or image texture analysis in the visible light band, or rely on indirect physical quantities such as temperature and humidity sensors to infer road conditions. However, these techniques are susceptible to interference from stray light, sensor surface contamination, and changes in weather conditions, and cannot directly reflect the modulation effect of road materials on the polarization characteristics of light waves. Especially during dynamic driving, different road materials exhibit microscopic and rapidly changing optical characteristics regarding the rotation and depolarization of polarized light. These optical characteristics are intrinsically related to the material's surface roughness, dielectric constant, and moisture content, but their changing patterns are subtle and difficult to extract. Therefore, they are difficult to directly perceive and quantify using conventional optical sensing methods, making it challenging for existing technologies to achieve accurate identification and timely adaptation of lighting patterns based on the inherent optical properties of road materials.

[0019] Therefore, please refer to Figure 1 As shown, this invention provides a laser vehicle lighting method that, by actively emitting a laser beam and analyzing the depolarization characteristics of the reflected light from the road surface, achieves accurate identification of road surface conditions and adaptive adjustment of the lighting mode. The method specifically includes the following steps: S11. Control the laser headlights at the front of the vehicle to emit laser beams to illuminate the road surface in front of the vehicle. S12. Receive the reflected light signal from the road surface, and determine the polarization rotation angle and extinction ratio of the laser beam based on the reflected light signal from the road surface. The extinction ratio reflects the degree of depolarization of the laser beam by the material of the road surface. S13. Compare the polarization rotation angle and extinction ratio with the preset template to determine the road surface condition type of the road surface in front of the vehicle. S14. Adjust the lighting mode of the laser headlights according to the road surface condition type.

[0020] In this embodiment, a laser headlight deployed at the front of the vehicle is controlled to emit a laser beam of a specific wavelength onto the road surface area ahead of the vehicle's travel direction. The core component of this laser headlight is a semiconductor laser, whose coherent light is passed through a fluorescent material to form an illumination beam, maintaining both the high collimation characteristics of the laser and ensuring that the output beam meets safety lighting standards. The emission process is triggered by the headlight control module, and the beam coverage area is matched to the vehicle's travel trajectory, forming an active illumination area on the road surface ahead.

[0021] After a laser beam illuminates the road surface, a polarization-sensitive receiver deployed at the front of the vehicle collects the scattered light signal reflected from the road surface. This signal is processed by photoelectric conversion to generate an electrical signal, which can then be used to calculate two core optical parameters using polarization analysis algorithms: the polarization rotation angle and the extinction ratio. The polarization rotation angle refers to the angular offset of the reflected light relative to the incident light in the polarization direction. This angular offset originates from the anisotropic modulation effect of the road surface material on the light wave. The extinction ratio is defined as the ratio of the intensities of the orthogonal polarization components of the polarized light after reflection from the road surface. This extinction ratio quantifies the degree to which the road surface material causes polarization state disorder, i.e., the degree of depolarization. The smaller the value, the more significant the depolarization effect and the stronger the material's ability to disrupt the polarization state. It should be noted that different materials, such as dry asphalt, wet road surfaces, and snow-covered surfaces, will exhibit unique polarization modulation characteristics due to differences in surface roughness, moisture content, and crystal structure.

[0022] This embodiment constructs a two-dimensional feature vector from the extracted polarization rotation angle and extinction ratio, which is then input into a pre-defined road surface condition classification module. This module has a built-in standard template library containing various preset templates to reflect the polarization characteristic parameter range of typical road surface materials under baseline conditions. The comparison process employs a pattern matching mechanism, calculating the similarity distance between the current feature vector and each preset template, selecting the category with the highest matching degree as the recognition result, and outputting road surface condition types such as dry, wet, waterlogged, icy, and snowy. This recognition process directly utilizes the inherent optical properties of the road surface material, avoiding the shortcomings of traditional image recognition methods that are affected by changes in lighting and dirt.

[0023] Based on the determined road surface condition, the corresponding lighting mode is activated. The lighting mode includes a combination of parameters such as laser emission power adjustment, beam diffusion angle adjustment, and beam spot projection position optimization. For example, on icy and snowy roads, the beam divergence angle is increased to reduce specular reflection glare; on flooded roads, the projection angle is increased to reduce water reflection interference; and on dry roads, the standard high beam mode is used to achieve maximum illumination distance.

[0024] Preferably, when the road surface condition is determined to be wet asphalt or waterlogged, the elliptic polarization of the emitted laser beam can be adjusted in reverse according to the extinction ratio, so that the difference in the extinction ratio between the road marking reflective material and the road substrate is expanded to a threshold range that can be clearly distinguished by the human visual system. Specifically, the laser beam is polarized, with linearly polarized light with a phase delay of 90 degrees applied to the road centerline area, and ellipticly polarized light with a phase delay of 45 degrees applied to the road background area. The significant difference in the polarization rotation angle after reflection improves the recognition of the markings and solves the technical problems of blurred markings and reduced contrast on wet roads under traditional lighting.

[0025] This embodiment establishes a direct mapping between the polarization characteristics of road surface materials and lighting control by actively emitting laser beams and receiving road surface reflection signals. It bypasses the reliance on macroscopic visual features such as texture and color in traditional image recognition, fully utilizing the microscopic physical effects of modulating the polarization state of light waves at the molecular scale of the road surface to achieve optical perception of the essential properties of the road surface material. Because polarization information is less susceptible to interference from stray light and highly sensitive to material differences, the recognition accuracy is significantly improved. Simultaneously, the recognition results are converted into real-time lighting parameter adjustments, allowing the beam characteristics to actively adapt to the optical response characteristics of the road surface. This fundamentally suppresses safety hazards such as specular glare on icy and snowy roads and light curtain interference on waterlogged roads, solving the problem of optical mismatch between fixed lighting modes and actual road conditions. This upgrades the laser vehicle headlight from a passive lighting device to an intelligent optical system with environmental perception capabilities.

[0026] Preferably, the laser beam is polarized by a polarizer and emitted as linearly polarized light. After illuminating the road surface, it is reflected, and the angle between the polarization direction of the reflected light and the initial polarization direction of the emitted light is the polarization rotation angle.

[0027] Preferably, the laser beam is polarized by a polarizer and emitted as linearly polarized light. After illuminating the road surface, it is reflected. When the reflected light passes through the analyzer, the analyzer is rotated to the position of the maximum light intensity received by the photodetector and the first light intensity value at this position is recorded. Then the analyzer is rotated to the position of the minimum light intensity and the second light intensity value at this position is recorded. The ratio of the first light intensity value to the second light intensity value is the extinction ratio.

[0028] Preferably, the road surface condition type includes the material type and humidity level information of the road surface.

[0029] In one embodiment, adjusting the illumination mode of the laser headlights according to the road surface condition type includes: When the road surface condition is wet asphalt road surface, reduce the illumination intensity of the laser headlights and increase the divergence angle of the laser beam to a preset value; When the road surface condition is a waterlogged road surface, the blue laser of the laser headlight is turned off, and the lateral scanning angle of the red and green lights is increased to form a fan-shaped light curtain; When the road surface condition is dry and rough, the laser headlights are adjusted to the standard lighting mode, and the power of the laser headlights is increased to the standard value.

[0030] This embodiment can provide differentiated lighting control strategies for three typical road surface conditions, achieving an optimal balance between lighting effect and safety by precisely adjusting the laser output characteristics. The specific process is as follows: When the road surface condition is identified as wet asphalt, two linked adjustments are executed: First, the overall illumination intensity of the laser headlights is reduced to weaken the specular reflection component of the laser beam on the wet road surface, avoiding interference from strong light reflection on the driver's vision. Second, the divergence angle of the laser beam is actively increased, causing the originally concentrated beam to diffuse into a wider cone, expanding the illumination coverage. The divergence angle refers to the angle subtended by the laser beam as its energy distribution spreads with the propagation distance after being emitted from the light source. The larger the divergence angle, the wider the coverage area of ​​the beam in the far field, and the correspondingly lower the light intensity per unit area.

[0031] Because a water film forms on a wet asphalt surface, its smooth surface has a strong specular reflection tendency. If standard lighting intensity and a narrow beam are maintained, the reflected light will concentrate and refract in a single direction, forming a high-brightness glare point. Therefore, this embodiment can reduce the incident light energy by decreasing the lighting intensity and change the geometric distribution of the reflected light path by increasing the divergence angle, thus dispersing the reflected energy over a wider spatial angle. This significantly reduces the luminous flux density entering the driver's pupil, thereby suppressing the glare effect while ensuring visibility in the lateral area of ​​the road surface.

[0032] When the road surface condition is identified as a flooded road, the blue laser in the laser headlights is turned off, leaving only the red and green lasers operational. Simultaneously, the horizontal scanning angle of the red and green lasers is increased, ultimately creating a fan-shaped light curtain illumination pattern. The horizontal scanning angle refers to the range of angles the laser beam swings left and right in the horizontal direction. This can be dynamically adjusted in position on the horizontal plane by controlling the optical deflection mechanism, thereby changing the lateral coverage area of ​​the illumination.

[0033] Because of the highly specular reflective properties of stagnant water surfaces and the low absorption rate of blue light by water, blue light is strongly reflected directionally from the surface, easily creating dazzling glare. Turning off the blue laser eliminates this risk at its source. Simultaneously, increasing the lateral scanning angle of the red and green light beams allows the laser beam to oscillate rapidly across the horizontal plane, creating a fan-shaped illumination distribution instead of a traditional concentrated spot. This fan-shaped light curtain significantly widens the illumination coverage, allowing the laser beam to project beyond the stagnant water area to a greater distance ahead, avoiding blind spots caused by water reflections while maintaining the ability to identify lane edges and obstacles ahead.

[0034] When the road surface condition recognition result is dry and rough, the laser headlights are adjusted to the standard lighting mode, and the laser emission power is increased to the standard value.

[0035] Because dry, rough road surfaces are covered with tiny particles and irregular textures, incident light primarily undergoes diffuse reflection, preventing strong specular glare and exhibiting excellent optical tolerance. This standard lighting mode employs optimized beam collimation and divergence angle configurations to concentrate light energy directly forward. Furthermore, simultaneously increasing the power to the standard value fully leverages the high brightness of the laser source, achieving maximum illumination distance and highest center illuminance, providing ample forward visibility for high-speed driving. In this state, no optical suppression or dispersion treatment is required, fully unleashing the lighting potential of the laser headlights.

[0036] In one embodiment, please refer to Figure 2 As shown, the step of comparing the polarization rotation angle and extinction ratio with a preset template to determine the road surface condition type of the road surface in front of the vehicle includes: S131. Convert the polarization rotation angle into a first voltage signal, and convert the extinction ratio into a second voltage signal; S132. The first voltage signal and the second voltage signal are respectively input to the first input terminal and the second input terminal of the parallel comparison array. The parallel comparison array includes multiple comparison units. Each comparison unit stores a reference voltage pair corresponding to a preset template. Each reference voltage pair includes a third voltage signal and a fourth voltage signal. S133. Each comparison unit compares the voltage amplitude of the first voltage signal and the third voltage signal, and compares the voltage amplitude of the second voltage signal and the fourth voltage signal. When the amplitude difference between the first voltage signal and the third voltage signal is less than the amplitude difference between the second voltage signal and the fourth voltage signal, the comparison unit outputs a first level; otherwise, it outputs a second level. The output terminals of all comparison units are connected to the judgment unit. S134. The judgment unit allows only the highest priority first level to pass through at any time, blocks the second level and other priority first levels, and encodes the passed first level as the road surface state type.

[0037] This embodiment can convert the polarization rotation angle and extinction ratio obtained from the front-end processing into corresponding first voltage signals and second voltage signals, respectively, so that the digital quantity representing the optical characteristics of the road surface is mapped into a continuous analog voltage amplitude. The voltage level corresponds to the original optical parameters, thereby converting the abstract optical parameters into electrical signals that can be directly processed by analog circuits.

[0038] The first and second voltage signals are synchronously input to the corresponding input terminals of the parallel comparison array. This parallel comparison array consists of multiple independent comparison units, each storing a set of reference voltage pairs. The third voltage signal corresponds to the reference polarization rotation angle of a certain type of road surface material, and the fourth voltage signal corresponds to the reference extinction ratio of the same type of road surface. All comparison units in the array operate simultaneously, each corresponding to a preset road surface state template. The parallel comparison array is a synchronously operating circuit cluster composed of multiple independent comparison units. Each unit performs the same comparison operation in parallel within the same clock cycle, making it suitable for scenarios requiring rapid matching of multiple templates and significantly reducing recognition latency.

[0039] Within each comparison unit, the amplitude difference between the first and third voltage signals is calculated in real time, as well as the amplitude difference between the second and fourth voltage signals. If the amplitude difference of the former is less than that of the latter, the comparison unit determines that the current road surface state matches the template stored internally and outputs a first level; otherwise, it outputs a second level. The first level represents a successful match, and the second level represents a failed match. The outputs of all comparison units are connected in parallel to subsequent decision units, forming a multi-channel parallel decision signal stream.

[0040] The judgment unit employs a priority-based judgment mechanism. At any given time, only the highest-priority first level is allowed to pass through the outputs of all comparison units, while the second level and other lower-priority first levels are blocked. The passed first level is encoded as the corresponding road surface state type and output as the final recognition result. This mechanism ensures that when multiple templates simultaneously meet the approximate matching conditions, a unique decision can be made quickly based on preset priorities, avoiding output ambiguity.

[0041] This embodiment achieves microsecond-level ultra-high-speed road condition recognition by converting optical parameters into analog voltages and employing a hardware parallel comparison architecture, avoiding the latency accumulation problem caused by serial instruction execution in traditional software algorithms. The parallel operation mode of multiple comparison units enables the system to complete the synchronous comparison of all templates within a single clock cycle, with response speed independent of the number of templates, significantly improving real-time perception capabilities in dynamic driving environments. Simultaneously, the amplitude difference comparison mechanism uses analog circuits to implement similarity measurement, eliminating the need for complex numerical calculations and reducing system power consumption and hardware complexity. Furthermore, the priority encoding mechanism ensures decision-making accuracy when multiple templates conflict, preventing output jitter caused by simultaneous triggering of multiple templates due to measurement noise. Moreover, this embodiment hardens the algorithm flow, which originally relied on digital signal processors or microcontrollers, into dedicated analog circuits, not only improving recognition speed and reliability but also enhancing the system's operational stability in harsh vehicle environments such as strong electromagnetic interference and extreme temperature and humidity, providing a solid hardware foundation for millisecond-level rapid switching of laser headlight illumination modes.

[0042] Preferably, the number of comparison units in the parallel comparison array is equal to the number of road surface state types, and each comparison unit corresponds to a unique preset template.

[0043] In one embodiment, determining the polarization rotation angle and extinction ratio of the laser beam based on the reflected light signal from the road surface includes: The reflected light signal is photoelectrically converted to generate an electrical signal sequence; The electrical signal sequence is digitally sampled to obtain the original data stream; The original data stream is time-aligned and reconstructed, and Stokes vector components are extracted from the reconstructed waveform data. The polarization rotation angle and extinction ratio are calculated based on the Stokes vector components. The Stokes vector components include the phase offset and amplitude value of the waveform data.

[0044] In this embodiment, the polarized light signal reflected from the road surface is received and converted into a continuously varying electrical signal sequence over time using a photodetector. The photosensitive element inside the photodetector converts photon energy into electronic signals, and the voltage or current amplitude of the output electrical signal sequence is proportional to the intensity of the reflected light, thereby realizing the mapping of light intensity information to electrical quantities.

[0045] A continuous electrical signal sequence undergoes analog-to-digital conversion, and the amplitude of the electrical signal is discretized at a fixed frequency to generate a raw data stream in digital form. The digital sampling process converts the continuous signal on the time axis into a series of discrete data points, each containing amplitude information and a timestamp, enabling the signal to be stored, transmitted, and processed by a digital signal processor.

[0046] Timing alignment is performed on the raw data stream to correct time deviations caused by factors such as optical path transmission delays, electronic device response time differences, and optical path changes due to vehicle vibration, ensuring strict synchronization of transmitted and received signals on the time base. After timing alignment, waveform reconstruction is performed, using interpolation and filtering algorithms to recover waveform details that may have been lost due to sampling discretization, eliminating noise and distortion, and obtaining smooth waveform data that is faithful to the original physical process.

[0047] Stokes vector components, consisting of four parameters, are extracted from the reconstructed waveform data to fully describe the polarization state of the light wave. This embodiment focuses on the components related to linear polarization: the rotation information of the polarization direction is obtained by analyzing the phase offset of the waveform data, and the intensity distribution information of the orthogonal polarization direction is obtained by the amplitude value. Finally, the polarization rotation angle and extinction ratio are calculated based on the mathematical relationships between the components of the Stokes vector.

[0048] Among them, the phase offset is the angular shift of the electric field vector vibration direction of polarized light relative to the reference reference during transmission. This shift is directly mapped to the polarization rotation angle and is the core parameter for calculating the anisotropic effect of road surface material.

[0049] This embodiment can transform the complex optical information reflected from the road surface into standardized polarization rotation angles and extinction ratios, providing stable and reliable input features for road condition recognition. Secondly, time alignment and waveform reconstruction effectively overcome signal distortion problems caused by mechanical vibration, temperature drift, and device aging in the vehicle environment, ensuring measurement consistency during long-term vehicle operation. Furthermore, compared to traditional direct intensity ratio calculation methods, the Stokes vector analysis method has higher anti-interference capabilities and measurement accuracy. Even under conditions of weak reflection or strong background light interference, it can accurately extract polarization features, solving the technical challenge of easily attenuating polarization measurement accuracy in dynamic driving scenarios. This provides high signal-to-noise ratio input data for subsequent template matching and lighting mode decision-making, ensuring the response accuracy of the entire laser vehicle headlight adaptive system.

[0050] In one embodiment, the step of performing time alignment and waveform reconstruction on the original data stream, extracting Stokes vector components from the reconstructed waveform data, and calculating the polarization rotation angle and extinction ratio based on the Stokes vector components includes: Based on the original data stream, a sequence of emission time markers for the laser beam is constructed, and each emission time marker is paired with its corresponding reception time marker to obtain a marker pair; Calculate the time delay value between the tag pairs, remove abnormal tag pairs whose time delay values ​​exceed a preset range, and perform interpolation on the retained tag pairs to obtain waveform data; The waveform data is divided into multiple waveform windows, each of which includes a complete pulse cycle; The phase offset of the waveform data within each waveform window is extracted, and the phase offset is converted into an angle offset to obtain multiple initial polarization rotation angles; Extract the maximum and minimum amplitude values ​​of the waveform data within each waveform window, calculate the ratio of the maximum amplitude value to the minimum amplitude value, and obtain multiple initial extinction ratio values; The initial polarization rotation angles calculated from multiple consecutive waveform windows are combined into an angle sequence, and the angle sequence is filtered by moving average to obtain the polarization rotation angle. The initial extinction ratio values ​​calculated from multiple consecutive waveform windows are combined into an extinction ratio sequence. The extinction ratio sequence is then subjected to median filtering to obtain the extinction ratio value.

[0051] In this embodiment, the sequence of emission time markers for the laser beam is parsed from the raw data stream, and each emission time marker is paired with its corresponding reception time marker to form a marker pair. The emission time marker records the precise time point of the laser diode's activation light pulse, and the reception time marker records the arrival time point of the road surface reflected light captured by the polarization-sensitive receiver. The two are associated through a unique identifier to establish a time reference anchor point for the round-trip process of the beam.

[0052] The time delay value between each pair of markers is calculated, reflecting the flight time of the laser pulse from emission to reception. Abnormal marker pairs whose time delay values ​​exceed a preset range are discarded. This range can be constrained by factors such as the speed of light, the installation height of the vehicle headlights, and the maximum detection distance. Values ​​exceeding this range indicate that the time relationship of the marker pair is disordered due to noise interference, multipath reflection, or signal loss, and are therefore invalid data. Interpolation is performed on the retained valid marker pairs to fill the discrete time markers with continuous values, reconstructing a complete and smooth waveform data and restoring the waveform breaks caused by sampling discretization or marker loss.

[0053] The reconstructed waveform data is divided into multiple waveform windows, each with a width strictly encompassing a complete pulse period. A complete pulse period refers to the time interval from the start of the pulse's rising edge to the start of the next pulse's rising edge, including the entire process of pulse setup, peak sustaining, and decay. Window segmentation ensures that each analysis unit contains complete polarization modulation information, avoiding feature extraction distortion caused by pulse truncation at window boundaries.

[0054] The phase offset of the waveform data within each waveform window is extracted. This phase offset can be obtained by comparing the zero-crossing time difference of the received waveform relative to the transmitted waveform or the peak position of the correlation function. The phase offset is converted into an angular offset based on a fixed ratio between the phase period and the angular period. Each window obtains an initial polarization rotation angle to achieve a spatial domain mapping from the time-domain waveform to the polarization angle, thus converting the microscopic time shift of the continuous waveform into a quantifiable angular quantity.

[0055] The maximum and minimum amplitude values ​​of the waveform data within each waveform window are extracted. The maximum amplitude value corresponds to the peak intensity of the polarized light in the main polarization direction, and the minimum amplitude value corresponds to the valley intensity in the orthogonal polarization direction. The ratio of the maximum amplitude value to the minimum amplitude value is calculated to obtain the initial extinction ratio. This ratio reflects the depolarization intensity of the road surface material on the polarized light within a single pulse cycle.

[0056] The initial polarization rotation angles calculated from multiple consecutive waveform windows are arranged into an angle sequence in chronological order. This sequence is then processed by a moving average filter. The moving average filter uses a fixed-length sliding window to gradually shift across the sequence, taking the arithmetic mean of the angle values ​​within each window, and outputting the smoothed polarization rotation angle. This effectively suppresses high-frequency random fluctuations caused by vehicle vibration, light spot jitter, and detector noise, while preserving the true angle change trend caused by the polarization characteristics of the road surface material itself.

[0057] Furthermore, the initial extinction ratio values ​​calculated from multiple consecutive waveform windows are combined into an extinction ratio sequence, which is then subjected to median filtering. Median filtering uses a fixed-length window that slides across the sequence, taking the median of the extinction ratio values ​​within each window, and outputting the filtered extinction ratio value. This provides strong robustness against occasional abnormal pulses, sudden interference, or random measurement errors, completely eliminating discrete noise without affecting the normal data distribution and ensuring the stability of the extinction ratio parameter.

[0058] This embodiment establishes a strict signal validity screening criterion through transmission and reception timing pairing and abnormal delay elimination methods, fundamentally eliminating the contamination of polarization measurements by multipath interference and noise misjudgment, and ensuring the purity of the data source. Furthermore, interpolation reconstruction compensates for information loss caused by discrete sampling, restoring the waveform to a near-real continuous state, laying the foundation for high-precision feature extraction. Simultaneously, the multi-window segmentation strategy transforms the continuous data stream into independent analysis units, realizing parallel processing potential while avoiding boundary truncation errors through periodic integrity constraints. The use of moving average filtering on the angle sequence effectively smooths random disturbances introduced by high-frequency vehicle vibration and optical jitter, ensuring that the polarization rotation angle reflects the inherent properties of the road surface material rather than instantaneous interference. In addition, the use of median filtering on the extinction ratio sequence fully utilizes its strong suppression capability against abrupt noise, preventing outliers caused by occasional strong light flicker or detector saturation from contaminating the final parameters. The differentiated selection of the two filters reflects a precise grasp of the noise characteristics of different parameters; moving average preserves the continuous trend, while median filtering eliminates discrete impact interference, jointly improving the temporal stability and measurement reliability of the polarization parameters.

[0059] Please refer to Figure 3 As shown, one embodiment of the present invention also provides a laser vehicle light illumination device, comprising: The transmitting module 31 is used to control the laser headlights at the front of the vehicle to emit laser beams to illuminate the road surface in front of the vehicle. The receiving module 32 is used to receive the reflected light signal from the road surface and determine the polarization rotation angle and extinction ratio of the laser beam based on the reflected light signal from the road surface. The extinction ratio reflects the degree of depolarization of the laser beam by the material of the road surface. The determination module 33 is used to compare the polarization rotation angle and extinction ratio with a preset template to determine the road surface condition type of the road surface in front of the vehicle. The adjustment module 34 is used to adjust the lighting mode of the laser vehicle light according to the road surface condition type.

[0060] This invention provides a laser vehicle headlight illumination device that actively illuminates the road surface by emitting a laser beam and receiving the reflected light signal. It directly determines the polarization rotation angle and extinction ratio, converting the microscopic depolarization characteristics of the road surface material into quantifiable optical parameters. These parameters are then compared with a preset template to determine the road surface condition type, thereby adjusting the laser headlight's illumination mode. This establishes a direct mapping relationship between the polarization modulation characteristics of the road surface material and lighting control, enabling the perception and feedback of the road surface material's optical properties. This ensures precise matching of the lighting mode adjustment with the actual optical response characteristics of the road surface material, effectively suppressing adverse optical effects, improving lighting effectiveness, and avoiding potential safety hazards for drivers.

[0061] Regarding the lighting device in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0062] In one embodiment, the present invention also provides a storage medium storing computer-readable instructions, which, when executed by one or more processors, cause the one or more processors to perform the aforementioned laser vehicle light illumination method. The storage medium may be a ROM, random access memory (RAM), CD-ROM, magnetic tape, floppy disk, or optical data storage device, etc.

[0063] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This computer program can be stored in a storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The aforementioned storage medium can be a non-volatile storage medium such as a magnetic disk, optical disk, or read-only memory (ROM), or random access memory (RAM).

[0064] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for illuminating a laser vehicle headlight, characterized in that, include: Control the laser headlights at the front of the vehicle to emit laser beams to illuminate the road surface in front of the vehicle; The system receives the reflected light signal from the road surface and determines the polarization rotation angle and extinction ratio of the laser beam based on the reflected light signal from the road surface. The extinction ratio reflects the degree of depolarization of the laser beam by the material of the road surface. The polarization rotation angle and extinction ratio are compared with a preset template to determine the road surface condition type of the road surface in front of the vehicle. The illumination mode of the laser headlights is adjusted according to the road surface condition type; The step of comparing the polarization rotation angle and extinction ratio with a preset template to determine the road surface condition type ahead of the vehicle includes: The polarization rotation angle is converted into a first voltage signal, and the extinction ratio is converted into a second voltage signal; The first voltage signal and the second voltage signal are respectively input to the first input terminal and the second input terminal of the parallel comparison array. The parallel comparison array includes multiple comparison units. Each comparison unit stores a reference voltage pair corresponding to a preset template. Each reference voltage pair includes a third voltage signal and a fourth voltage signal. Each comparison unit compares the voltage amplitude of the first voltage signal with the third voltage signal, and compares the voltage amplitude of the second voltage signal with the fourth voltage signal. When the amplitude difference between the first voltage signal and the third voltage signal is less than the amplitude difference between the second voltage signal and the fourth voltage signal, the comparison unit outputs a first level; otherwise, it outputs a second level. The output terminals of all comparison units are connected to the judgment unit. The judgment unit allows only the highest priority first level to pass through at any time, blocks the second level and other priority first levels, and encodes the passed first level as the road surface state type. The number of comparison units in the parallel comparison array is equal to the number of road surface state types, and each comparison unit corresponds to a unique preset template.

2. The method according to claim 1, characterized in that, The laser beam is polarized into linearly polarized light by a polarizer and emitted. After illuminating the road surface, it is reflected. The angle between the polarization direction of the reflected light and the initial polarization direction of the emitted light is the polarization rotation angle.

3. The method according to claim 1, characterized in that, The laser beam is polarized into linearly polarized light by a polarizer and emitted. After illuminating the road surface, it is reflected. When the reflected light passes through the analyzer, the analyzer is rotated to the position of the maximum light intensity received by the photodetector and the first light intensity value is recorded. Then the analyzer is rotated to the position of the minimum light intensity and the second light intensity value is recorded. The ratio of the first light intensity value to the second light intensity value is the extinction ratio.

4. The method according to claim 1, characterized in that, The road surface condition type includes the material type and humidity level information of the road surface.

5. The method according to claim 1, characterized in that, The step of adjusting the illumination mode of the laser vehicle lights according to the road surface condition type includes: When the road surface condition is wet asphalt road surface, reduce the illumination intensity of the laser headlights and increase the divergence angle of the laser beam to a preset value; When the road surface condition is a waterlogged road surface, the blue laser of the laser headlight is turned off, and the lateral scanning angle of the red and green lights is increased to form a fan-shaped light curtain; When the road surface condition is dry and rough, the laser headlights are adjusted to the standard lighting mode, and the power of the laser headlights is increased to the standard value.

6. The method according to claim 1, characterized in that, The step of determining the polarization rotation angle and extinction ratio of the laser beam based on the reflected light signal from the road surface includes: The reflected light signal is photoelectrically converted to generate an electrical signal sequence; The electrical signal sequence is digitally sampled to obtain the original data stream; The original data stream is time-aligned and reconstructed, and Stokes vector components are extracted from the reconstructed waveform data. The polarization rotation angle and extinction ratio are calculated based on the Stokes vector components. The Stokes vector components include the phase offset and amplitude value of the waveform data.

7. The method according to claim 6, characterized in that, The step of performing time alignment and waveform reconstruction on the original data stream, extracting Stokes vector components from the reconstructed waveform data, and calculating the polarization rotation angle and extinction ratio based on the Stokes vector components includes: Based on the original data stream, a sequence of emission time markers for the laser beam is constructed, and each emission time marker is paired with its corresponding reception time marker to obtain a marker pair; Calculate the time delay value between the tag pairs, remove abnormal tag pairs whose time delay values ​​exceed a preset range, and perform interpolation on the retained tag pairs to obtain waveform data; The waveform data is divided into multiple waveform windows, each of which includes a complete pulse cycle; The phase offset of the waveform data within each waveform window is extracted, and the phase offset is converted into an angle offset to obtain multiple initial polarization rotation angles; Extract the maximum and minimum amplitude values ​​of the waveform data within each waveform window, calculate the ratio of the maximum amplitude value to the minimum amplitude value, and obtain multiple initial extinction ratio values; The initial polarization rotation angles calculated from multiple consecutive waveform windows are combined into an angle sequence, and the angle sequence is filtered by moving average to obtain the polarization rotation angle. The initial extinction ratio values ​​calculated from multiple consecutive waveform windows are combined into an extinction ratio sequence. The extinction ratio sequence is then subjected to median filtering to obtain the extinction ratio value.

8. A lighting device for a laser vehicle light, characterized in that, include: The transmitting module is used to control the laser headlights at the front of the vehicle to emit laser beams to illuminate the road surface in front of the vehicle. The receiving module is used to receive the reflected light signal from the road surface and determine the polarization rotation angle and extinction ratio of the laser beam based on the reflected light signal from the road surface. The extinction ratio reflects the degree of depolarization of the laser beam by the material of the road surface. The determination module is used to compare the polarization rotation angle and extinction ratio with a preset template to determine the road surface condition type of the road surface in front of the vehicle. An adjustment module is used to adjust the lighting mode of the laser headlights according to the road surface condition type; The step of comparing the polarization rotation angle and extinction ratio with a preset template to determine the road surface condition type ahead of the vehicle includes: The polarization rotation angle is converted into a first voltage signal, and the extinction ratio is converted into a second voltage signal; The first voltage signal and the second voltage signal are respectively input to the first input terminal and the second input terminal of the parallel comparison array. The parallel comparison array includes multiple comparison units. Each comparison unit stores a reference voltage pair corresponding to a preset template. Each reference voltage pair includes a third voltage signal and a fourth voltage signal. Each comparison unit compares the voltage amplitude of the first voltage signal with the third voltage signal, and compares the voltage amplitude of the second voltage signal with the fourth voltage signal. When the amplitude difference between the first voltage signal and the third voltage signal is less than the amplitude difference between the second voltage signal and the fourth voltage signal, the comparison unit outputs a first level; otherwise, it outputs a second level. The output terminals of all comparison units are connected to the judgment unit. The judgment unit allows only the highest priority first level to pass through at any time, blocks the second level and other priority first levels, and encodes the passed first level as the road surface state type. The number of comparison units in the parallel comparison array is equal to the number of road surface state types, and each comparison unit corresponds to a unique preset template.

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