Illumination method and illumination device of laser vehicle lamp

Abstract

The invention provides an illumination method and device of a laser vehicle lamp, and the method comprises the steps: controlling the 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; a reflected light signal of the driving road surface is received, the polarization rotation angle and the extinction ratio of the laser beam are determined according to the reflected light signal of the driving road surface, and the extinction ratio reflects the depolarization degree of the material of the driving road surface to the laser beam; the polarization rotation angle and the extinction ratio are compared with a preset template, the road surface state type of the driving road surface in front of the vehicle is determined, the illumination mode of the laser vehicle lamp is adjusted according to the road surface state type, the adjustment of the illumination mode is accurately matched with the actual optical response characteristic of the road surface material, the bad optical effect is effectively inhibited, and the driving quality is improved. And potential safety hazards in driving are avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vehicle lighting technology, in particular to a laser vehicle lamp lighting method and lighting device. BACKGROUND

[0002] The laser beam of the laser vehicle lamp has the characteristics of high energy density and excellent collimation, can realize long-distance lighting, the lighting distance is twice that of the LED light source, and the energy efficiency is higher, which can significantly improve the visibility of the unlit road at night.

[0003] The existing laser vehicle lamp generally adopts a fixed lighting mode, but in the actual traffic environment, the driving surface contains dry asphalt, wet water, ice and snow coverage, sandstone paving and other material states, and the micro surface structure of different materials has essential differences in the polarization modulation characteristics of the laser beam, which causes the energy distribution of the laser beam to be mismatched with the optical characteristics of the road surface, resulting in strong mirror reflection on the ice and snow road surface, causing the driver to be dazzled, forming a light curtain on the water road surface, and the illumination is scattered and lost on the sandstone road surface. Illumination failure phenomenon, and such illumination failure phenomenon is particularly prominent under the condition of complex weather and road conditions, which is easy to cause driving safety hazards. SUMMARY

[0004] The present application provides a laser vehicle lamp lighting method and lighting device, which realizes the adjustment of the lighting mode and the precise matching of the actual optical characteristics of the road surface material, effectively suppresses the adverse optical effect, and avoids the driving safety hazard.

[0005] To solve the above problems, the present application adopts the following technical scheme: The present application provides a laser vehicle lamp lighting method, comprising: controlling the laser vehicle lamp at the front end of the vehicle to emit a laser beam to irradiate the driving surface in front of the vehicle; receiving the reflected light signal of the driving surface, determining the polarization rotation angle and the extinction ratio of the laser beam according to the reflected light signal of the driving surface, and the extinction ratio reflects the degree of depolarization of the driving surface material to the laser beam; comparing the polarization rotation angle and the extinction ratio with a preset template to determine the road surface state type of the driving surface in front of the vehicle; adjusting the lighting mode of the laser vehicle lamp according to the road surface state type.

[0006] Preferably, the laser beam forms linearly polarized light after passing through a polarizer, and after irradiating the driving surface, the reflected light has a polarization direction that is rotated by an angle relative to the initial polarization direction of the outgoing light, and the angle is the polarization rotation angle.

[0007] Preferably, the laser beam is linearly polarized by a polarizer, and after irradiating the driving surface, the reflected light is received by a photoelectric detector. The polarizer is rotated to the position where the light intensity is the maximum, and the first light intensity value is recorded. Then, the polarizer is rotated to the position where the light intensity is the minimum, 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 state type includes the material type and the moisture level information of the driving surface.

[0009] Further, the adjustment of the lighting mode of the laser car light according to the road surface state type comprises: When the road surface state type is a wet asphalt surface, the lighting intensity of the laser car light is reduced, and the divergence angle of the laser beam is increased to a preset value; When the road surface state type is a waterlogged surface, the blue laser of the laser car light is turned off, and the horizontal scanning angle of the red and green light is increased to form a fan-shaped light curtain; When the road surface state type is a dry and rough surface, the laser car light is adjusted to a standard lighting mode, and the power of the laser car light is increased to a standard value.

[0010] Further, the comparison of the polarization rotation angle and the extinction ratio with a preset template to determine the road surface state type of the driving surface in front of the vehicle comprises: 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 into the first input end and the second input end of a parallel comparison array, the parallel comparison array comprises a plurality of comparison units, each of which stores a reference voltage pair corresponding to a preset template, and each of the reference voltage pairs comprises a third voltage signal and a fourth voltage signal; Each of the comparison units compares the first voltage signal with the third voltage signal in terms of voltage amplitude, and compares the second voltage signal with the fourth voltage signal in terms of voltage amplitude. When the amplitude difference between the first voltage signal and the third voltage signal is smaller 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 ends of all comparison units are connected to a judgment unit. The judgment unit only allows the first level with the highest priority to pass at any time, blocks the second level and the first levels with other priorities, and encodes the passing 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 of the comparison units corresponds to a unique preset template.

[0012] Further, the determining the polarization rotation angle and the extinction ratio of the laser beam according to the reflected light signal of the driving surface comprises: photoelectrically converting the reflected light signal to generate an electric signal sequence; digitally sampling the electric signal sequence to obtain an original data stream; aligning the original data stream in time sequence and reconstructing the waveform, extracting a Stokes vector component from the reconstructed waveform data, and calculating the polarization rotation angle and the extinction ratio according to the Stokes vector component, wherein the Stokes vector component comprises a phase offset and an amplitude value of the waveform data.

[0013] Further, the aligning the original data stream in time sequence and reconstructing the waveform, extracting a Stokes vector component from the reconstructed waveform data, and calculating the polarization rotation angle and the extinction ratio according to the Stokes vector component comprises: constructing a transmission time marker sequence of the laser beam according to the original data stream, pairing each transmission time marker with a corresponding receiving time marker to obtain a marker pair; calculating a time delay value between the marker pairs, eliminating abnormal marker pairs with the time delay value exceeding a preset interval, and performing interpolation operation on the remaining marker pairs to obtain waveform data; dividing the waveform data into a plurality of waveform windows, and each waveform window comprising a complete pulse period; extracting a phase offset of the waveform data in each waveform window, and converting the phase offset into an angle offset to obtain a plurality of initial polarization rotation angles; extracting a maximum amplitude value and a minimum amplitude value of the waveform data in each waveform window, and calculating a ratio of the maximum amplitude value to the minimum amplitude value to obtain a plurality of initial extinction ratios; grouping the initial polarization rotation angles calculated by a plurality of continuous waveform windows into an angle sequence, and performing sliding average filtering on the angle sequence to obtain a polarization rotation angle; grouping the initial extinction ratios calculated by a plurality of continuous waveform windows into an extinction ratio sequence, and performing median filtering on the extinction ratio sequence to obtain an extinction ratio.

[0014] The application further provides a lighting device of a laser vehicle lamp, comprising: a transmission module configured to control the laser vehicle lamp at the front end of the vehicle to emit a laser beam to irradiate a driving surface in front of the vehicle; a receiving module configured to receive a reflected light signal of the driving surface, and determine a polarization rotation angle and an extinction ratio of the laser beam according to the reflected light signal of the driving surface, wherein the extinction ratio reflects a degree of depolarization of the laser beam caused by the material of the driving surface. determining module is configured to compare 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. adjusting module is configured to adjust the illumination mode of the laser vehicle lamp according to the road surface state type.

[0015] Compared with the prior art, the technical scheme of the present application has at least the following advantages: The laser vehicle lamp illumination method and the illumination device provided by the present application directly determine the polarization rotation angle and the extinction ratio by actively irradiating the driving road surface with a laser beam and receiving the reflected light signal, convert the microscopic depolarization characteristics of the road surface material into quantifiable optical parameters, determine the road surface state type after comparing with a preset template, and then adjust the illumination mode of the laser vehicle lamp, thereby establishing a direct mapping relationship from the polarization modulation characteristics of the road surface material to the illumination control, realizing the perception and feedback of the optical characteristics of the road surface material, making the adjustment of the illumination mode accurately match the actual optical response characteristics of the road surface material, effectively suppressing adverse optical effects, improving the illumination effectiveness, and avoiding driving safety hazards for the driver. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The figure is a flow chart of an embodiment of the laser vehicle lamp illumination method of the present application. Figure 2 The figure is a flow chart of another embodiment of the laser vehicle lamp illumination method of the present application. Figure 3 The figure is a structural block diagram of an embodiment of the laser vehicle lamp illumination device of the present application. DETAILED DESCRIPTION

[0017] In order to enable personnel in the technical field to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings.

[0018] In the prior art, when solving the problem of road surface adaptive lighting, the intensity sensing, color recognition or image texture analysis of the visible light band are usually focused on, or indirect physical quantities such as temperature sensing and humidity sensing are relied on to infer the road surface state. However, the above technical means are easily affected by factors such as environmental stray light interference, sensor surface contamination, and climate condition changes, and cannot directly reflect the modulation effect of the road surface material on the polarization characteristics of the light wave. Especially during dynamic driving, different road surface materials present microscopic and rapid changes in the optical characteristics of the rotation and depolarization degree of polarized light, which has an inherent correlation with the surface roughness, dielectric constant and water content of the material. However, the change rule is hidden and the signal is difficult to extract, so it is difficult to directly perceive and quantify by using conventional optical sensing means, which makes it difficult for the prior art to achieve precise identification based on the inherent optical characteristics of the road surface material and timely adaptation of the lighting mode.

[0019] Therefore, referring to Figure 1 The present application provides a laser vehicle lamp lighting method, which realizes precise identification of road surface state type and adaptive adjustment of lighting mode by actively emitting a laser beam and analyzing the depolarization characteristics of the reflected light from the road surface. The method specifically includes the following steps: S11, controlling a laser vehicle lamp disposed at the front end of a vehicle to emit a laser beam to irradiate a driving road surface in front of the vehicle; S12, receiving a reflected light signal from the driving road surface, and determining a polarization rotation angle and an extinction ratio of the laser beam according to the reflected light signal, wherein the extinction ratio reflects the depolarization degree of the laser beam caused by the material of the driving road surface; S13, 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; S14, adjusting a lighting mode of the laser vehicle lamp according to the road surface state type.

[0020] In this embodiment, a laser vehicle lamp disposed at the front end of a vehicle is controlled to emit a laser beam of a specific wavelength to the front road surface area in the driving direction of the vehicle. The core component of the laser vehicle lamp is a semiconductor laser, and the coherent light generated thereby passes through a fluorescent material to form an illumination light beam, which not only maintains the high collimation characteristics of the laser but also ensures that the output light beam meets the safety lighting standards. The emission process is triggered by a vehicle lamp control module, and the light beam coverage range matches the vehicle driving track to form an active irradiation area of the front road surface.

[0021] After the laser beam irradiates the road surface, the polarization-sensitive receiving device deployed at the front of the vehicle collects the scattered light signal formed by the reflection of the road surface. The signal is converted into an electrical signal through photoelectric conversion processing, and two core optical parameters can be calculated by a polarization analysis algorithm: the polarization rotation angle and the extinction ratio. Among them, the polarization rotation angle refers to the angle offset of the reflected light relative to the incident light in the polarization direction, which is caused by the anisotropic modulation of the road surface material to the light wave. The extinction ratio is defined as the ratio of the intensity of the orthogonal polarization components of the polarized light after reflection by the road surface. This extinction ratio quantifies the degree of polarization state disorder caused by the road surface material, i.e., the degree of depolarization. The smaller the value, the more significant the depolarization effect, and the stronger the material's ability to destroy the polarization state. It should be noted that different materials such as dry asphalt, wet road surface, and ice and snow cover have unique polarization modulation characteristics due to differences in surface roughness, water content, and crystal structure.

[0022] The extracted polarization rotation angle and extinction ratio can be used to form a two-dimensional feature vector, which is input into a pre-set road surface state classification module. The module has a built-in standard template library, which stores a variety of pre-set templates reflecting the polarization characteristic parameter range of typical road surface materials under reference conditions. The comparison process can use a pattern matching mechanism to calculate the similarity distance between the current feature vector and each pre-set template, select the class with the highest matching degree as the recognition result, and output the road surface state types such as dry, wet, water accumulation, icy, and snowy. This recognition process directly utilizes the optical characteristics of the road surface material itself, avoiding the defects of traditional image recognition affected by light changes and stains.

[0023] According to the determined road surface state type, the corresponding lighting mode is activated. The lighting mode includes parameter combinations such as laser emission power adjustment, beam divergence angle adjustment, and spot projection position optimization. For example, in icy and snowy road surfaces, the beam divergence angle is increased to reduce specular reflection glare, in water accumulation road surfaces, the projection angle is increased to reduce water reflection interference, and in dry road surfaces, the standard high beam mode is used to achieve the maximum illumination distance.

[0024] Preferably, when the road surface state type is determined to be wet asphalt or water accumulation road surface, the elliptical polarization degree of the laser beam exit can be adjusted in reverse according to the extinction ratio, so that the reflection extinction ratio difference between the road marking reflective material and the road surface base material is expanded to a threshold range that can be clearly distinguished by the human eye visual system. Specifically, the polarization state of the laser beam is modulated, linearly polarized light with a phase delay of ninety degrees is applied to the road centerline area, and elliptically polarized light with a phase delay of forty-five degrees is applied to the road background area. The significant difference in polarization rotation angle after reflection of the two can improve the identification of the mark and solve the technical problem of blurred mark and attenuated contrast on wet road surfaces under traditional lighting.

[0025] The embodiment can construct a direct mapping relationship from the polarization characteristics of the road surface material to the lighting control by actively emitting a laser beam and receiving a road surface reflection signal, bypass the texture, color and other macro visual features that the traditional image recognition relies on, fully utilize the micro physical effect of the road surface molecular scale modulation of the light wave polarization state, and realize the optical perception of the essential properties of the road surface material. Since the polarization information is not easily disturbed by environmental stray light and has high sensitivity to material differences, the recognition accuracy is significantly improved. At the same time, the recognition result is converted into lighting parameter adjustment in real time, so that the beam characteristics actively adapt to the optical response characteristics of the road surface, and the safety hazards such as the specular glare of the icy road surface and the light curtain interference of the waterlogged road surface are inhibited from the root, the problem of optical mismatch between the fixed lighting mode and the actual road condition is solved, and the laser vehicle lamp is upgraded from a passive lighting device to an intelligent optical system with environmental perception capability.

[0026] Preferably, the laser beam is formed into linearly polarized light by a polarizer and is reflected after irradiating the driving surface, and the angle generated by the polarization direction of the reflected light relative to the initial polarization direction of the outgoing light is the polarization rotation angle.

[0027] Preferably, the laser beam is formed into linearly polarized light by a polarizer and is reflected after irradiating the driving surface, and when the reflected light passes through the polarizer, the polarizer is rotated to the position of the maximum light intensity received by the photodetector and the first light intensity value of this position is recorded, and then the polarizer is rotated to the position of the minimum light intensity and the second light intensity value of this position is recorded, and the ratio of the first light intensity value to the second light intensity value is the extinction ratio.

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

[0029] In one embodiment, the adjusting the lighting mode of the laser vehicle lamp according to the road surface state type comprises: When the road surface state type is a wet asphalt road surface, the lighting intensity of the laser vehicle lamp is reduced, and the divergence angle of the laser beam is increased to a preset value; When the road surface state type is a waterlogged road surface, the blue laser of the laser vehicle lamp is turned off, and the horizontal scanning angle of the red and green light is increased to form a fan-shaped light curtain; When the road surface state type is a dry and rough road surface, the laser vehicle lamp is adjusted to a standard lighting mode, and the power of the laser vehicle lamp is increased to a standard value.

[0030] The embodiment can provide differentiated lighting control strategies for three typical road surface state types, and achieve optimal lighting effect and safety balance by accurately regulating the laser output characteristics, and the specific process is as follows: When the road surface state recognition result is a wet asphalt road surface, two linkage adjustments are performed: first, the overall illumination intensity of the laser car light is reduced to weaken the specular reflection component of the laser beam on the wet and slippery road surface, avoiding the interference of strong light reflection on the driver's vision. Second, the divergence angle of the laser beam is actively increased, so that the originally concentrated light beam is diffused into a wider light cone, expanding the irradiation coverage width. The divergence angle refers to the angular spread of the energy distribution of the laser beam as it propagates from the source, the larger the divergence angle, the wider the coverage range of the light beam in the far field, and the light intensity per unit area decreases accordingly.

[0031] Because a layer of water film will form on the wet asphalt surface, its smooth surface has a strong tendency to specularly reflect, if the standard illumination intensity and narrow light beam are maintained, the reflected light will be concentrated and returned along a single direction, forming a high-brightness glare point. Therefore, the embodiment can reduce the incident light energy by reducing the illumination intensity, and change the geometric distribution of the reflected light path by increasing the divergence angle, so that the reflected energy is dispersed to a wider spatial angle, significantly reducing the luminous flux density entering the driver's eye pupil, thereby suppressing the glare effect while ensuring the visibility of the lateral area of the road surface.

[0032] When the road surface state recognition result is a waterlogged road surface, the blue laser in the laser car light is turned off, only the red and green lasers are kept working, and the horizontal scanning angle of the red and green light is simultaneously increased, finally forming a fan-shaped light curtain illumination mode. The horizontal scanning angle refers to the angle range of the left and right swing of the laser beam in the horizontal direction, which can be adjusted dynamically by controlling the optical deflection mechanism to change the horizontal position of the light beam and adjust the horizontal coverage area of the illumination.

[0033] Because the waterlogged surface has a high specular reflection characteristic, and the water body has a low absorption rate for blue light band, leading to strong directional reflection of blue light on the waterlogged surface, which is easy to form dazzling glare. Turning off the blue laser can eliminate this risk from the source. At the same time, increasing the horizontal scanning angle of the red and green light makes the laser beam swing back and forth rapidly in the horizontal plane, building a fan-shaped light distribution instead of a traditional concentrated spot. The fan-shaped light curtain illumination mode significantly widens the illumination coverage range, enabling the laser beam to project to a farther place in front of the waterlogged area, avoiding the visual blind area caused by water surface reflection, while maintaining the recognition ability of the lane edge and the front obstacles.

[0034] When the road surface state recognition result is a dry and rough road surface, the laser car light is adjusted to the standard illumination mode, and the laser emission power is increased to the standard value.

[0035] Due to the surface of the dry and rough road surface is covered with small particles and irregular texture, the incident light on such surface mainly occurs diffuse reflection, and will not produce strong specular glare, with good optical resistance. The standard illumination mode uses the optimal beam collimation and divergence angle configuration, so that the light energy is concentrated to the front. In addition, the power is simultaneously increased to the standard value, which can fully exert the advantages of high brightness of laser light source, realize the farthest irradiation distance and the highest center illumination, and provide sufficient forward view for high-speed driving. In this state, no optical inhibition or dispersion treatment is needed, and the lighting potential of laser vehicle lamp can be fully released.

[0036] In one embodiment, referring to Figure 2 As shown in the figure, the polarization rotation angle and the extinction ratio value are compared with the preset template to determine the road surface state type of the driving road surface in front of the vehicle, which comprises: S131, converting the polarization rotation angle into a first voltage signal and converting the extinction ratio value into a second voltage signal; S132, inputting the first voltage signal and the second voltage signal into the first input end and the second input end of a parallel comparison array respectively, the parallel comparison array comprising a plurality of comparison units, each comparison unit internally storing a preset template corresponding reference voltage pair, each reference voltage pair comprising a third voltage signal and a fourth voltage signal; S133, each comparison unit compares the first voltage signal with the third voltage signal in voltage amplitude, and compares the second voltage signal with the fourth voltage signal in voltage amplitude, 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 outputs a second level, wherein the output ends of all comparison units are connected with a judgment unit; S134, the judgment unit only allows the first level with the highest priority to pass at any time, blocks the second level and the first level with other priorities, and encodes the passing first level as the road surface state type.

[0037] The embodiment can convert the polarization rotation angle and the extinction ratio value obtained by the front-end processing into corresponding first voltage signal and second voltage signal respectively, so as to map the digital quantity representing the optical characteristics of the road surface into continuous analog voltage amplitude, and the voltage level corresponds to the original optical parameter, thereby converting the abstract optical parameter into an electrical signal that can be directly processed by an analog circuit.

[0038] The first voltage signal and the second voltage signal are synchronously input to corresponding input ends of a parallel comparison array. The parallel comparison array is composed of a plurality of independent comparison units in an array structure, each comparison unit internally storing a group of reference voltage pairs, wherein the third voltage signal corresponds to a reference polarization rotation angle of a certain type of road surface material, and the fourth voltage signal corresponds to a reference extinction ratio of the same type of road surface. All comparison units in the array work simultaneously at the same time, each corresponding to a preset road surface state template. The parallel comparison array is a synchronous working circuit cluster composed of a plurality of independent comparison units, each unit performing the same comparison operation in parallel within the same clock cycle, suitable for multi-template fast matching scenarios, which can significantly shorten the recognition delay.

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

[0040] The judgment unit adopts a priority judgment mechanism, which allows only the highest priority first level to pass through from the outputs of all comparison units at any time, while blocking the second level and other lower priority first levels. The passing 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 condition, a unique decision can be made quickly based on the preset priority, avoiding ambiguous output.

[0041] The embodiment can achieve microsecond-level ultra-high-speed road surface state recognition by converting optical parameters into analog voltages and using a hardware parallel comparison architecture, avoiding the delay accumulation problem caused by serial execution of instructions in traditional software algorithms. The parallel working mode of multiple comparison units enables the system to complete synchronous comparison of all templates within a single clock cycle, regardless of the number of templates, significantly improving real-time perception capability in dynamic driving environments. At the same time, the amplitude difference comparison mechanism uses analog circuits to measure similarity, without the need for complex numerical calculations, reducing system power consumption and hardware complexity. In addition, the priority encoding mechanism ensures the accuracy of the decision when multiple templates conflict, preventing output jitter caused by multiple templates being triggered simultaneously due to measurement noise. Furthermore, the embodiment can harden the algorithm process that originally relies on digital signal processors or microcontrollers into a dedicated analog circuit, not only improving recognition speed and reliability, but also enhancing the working stability of the system in harsh vehicle environments such as strong electromagnetic interference and extreme temperature and humidity, providing a solid hardware foundation for millisecond-level fast switching of laser vehicle light 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 of the comparison units corresponds to a unique preset template.

[0043] In one embodiment, the determination of the polarization rotation angle and the extinction ratio of the laser beam according to the reflected light signal of the driving road surface comprises: photoelectric conversion of the reflected light signal to generate an electrical signal sequence; digital sampling of the electrical signal sequence to obtain an original data stream; time alignment and waveform reconstruction of the original data stream, extraction of Stokes vector components from the reconstructed waveform data, and calculation of the polarization rotation angle and the extinction ratio according to the Stokes vector components, wherein the Stokes vector components include phase shift and amplitude of the waveform data.

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

[0045] Analog-to-digital conversion is performed on the continuous electrical signal sequence, and the electrical signal amplitude is discretely extracted at a fixed frequency to generate a digital original data stream. The digital sampling process converts the continuous signal on the time axis into a series of discrete data points, each data point containing amplitude information and a timestamp, so that the signal can be stored, transmitted and operated by a digital signal processor.

[0046] A time alignment operation is performed on the original data stream to correct the time deviation caused by factors such as optical path variation due to optical transmission delay, electronic device response time difference, and vehicle vibration, ensuring that the transmitted and received signals are strictly synchronized in time reference. After completing the time alignment, waveform reconstruction is performed to recover the waveform details that may be lost due to sampling discretization using interpolation and filtering algorithms, eliminate noise and distortion, and obtain smooth and faithful waveform data to the original physical process.

[0047] Stokes vector components are extracted from the reconstructed waveform data, and the vector is composed of four parameters, which can completely 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 shift 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 the extinction ratio are calculated according to the mathematical relationship between the components of the Stokes vector.

[0048] The phase shift is an angle shift of an electric field vector vibration direction of the polarized light in a transmission process relative to a reference benchmark. The shift is directly mapped to a polarization rotation angle, which is a core parameter for calculating anisotropic effects of a road surface material.

[0049] The embodiment can convert complex optical information reflected by the road surface into a standardized polarization rotation angle and an extinction ratio, and provide stable and reliable input features for road surface state recognition. Secondly, the time sequence alignment and waveform reconstruction effectively overcome signal distortion problems caused by mechanical vibration, temperature drift, device aging and other factors in a vehicle-mounted environment, and ensure measurement consistency in long-term vehicle operation. In addition, compared with the traditional direct intensity ratio calculation method, the Stokes vector analysis method has higher anti-interference ability and measurement accuracy. Even in the condition of weak reflection or strong background light interference, the polarization features can still be accurately extracted, solving the technical problem of easy attenuation of polarization measurement accuracy in a dynamic driving scene. The high signal-to-noise ratio input data provided by the subsequent template matching and illumination mode decision ensures the response accuracy of the entire laser vehicle lamp adaptive system.

[0050] In one embodiment, the time sequence alignment and waveform reconstruction of the original data stream, and the extraction of the Stokes vector component from the reconstructed waveform data, the calculation of the polarization rotation angle and the extinction ratio according to the Stokes vector component include: According to the original data stream, a sequence of emission time markers of the laser beam is constructed, each emission time marker is paired with a corresponding receiving time marker, and a marker pair is obtained; Calculate the time delay value between the marker pairs, eliminate the abnormal marker pairs whose time delay values exceed the preset interval, and perform interpolation operation on the remaining marker pairs to obtain waveform data; The waveform data is divided into a plurality of waveform windows, and each waveform window includes a complete pulse period; Respectively extract the phase shift of the waveform data in each waveform window, and convert the phase shift into an angle shift to obtain a plurality of initial polarization rotation angles; Respectively extract the maximum amplitude value and the minimum amplitude value of the waveform data in each waveform window, calculate the ratio of the maximum amplitude value to the minimum amplitude value, and obtain a plurality of initial extinction ratios; The initial polarization rotation angles calculated by the continuous plurality of waveform windows are combined into an angle sequence, and the angle sequence is subjected to a sliding average filtering to obtain a polarization rotation angle; The initial extinction ratios calculated by the continuous plurality of waveform windows are combined into an extinction ratio sequence, and the extinction ratio sequence is subjected to a median filtering to obtain an extinction ratio.

[0051] In the embodiment, the emission time marker sequence of the laser beam is parsed from the original data stream, each emission time marker is paired with the corresponding reception time marker to form a marker pair. The emission time marker records the precise time point of the laser diode starting the light pulse, the reception time marker records the time point of the polarization-sensitive receiving device capturing the reflected light from the road surface, and the two are associated by a unique identification code to establish a time reference anchor point for the round trip process of the light beam.

[0052] The time delay value between each marker pair is calculated, which reflects the time of flight of the laser pulse from emission to reception. Abnormal marker pairs with time delay values exceeding a preset interval are removed, which can be constrained and set according to the speed of light, the installation height of the vehicle light, the maximum detection distance, etc. Exceeding the interval indicates that the marker pair is in a chaotic time relationship due to noise interference, multi-path reflection or signal loss, and is invalid data. Interpolation is performed on the remaining valid marker pairs to fill in continuous values between discrete time markers, and the complete and smooth waveform data is reconstructed to recover the waveform breakage caused by sampling discretization or marker loss.

[0053] The reconstructed waveform data is divided into multiple waveform windows, and the width of each waveform window strictly contains a complete pulse period. The complete pulse period refers to the period from the start of the pulse rising edge to the start of the next pulse rising edge, including the whole process of pulse establishment, peak maintenance and decay. Window segmentation ensures that each analysis unit contains complete polarization modulation information, avoiding feature extraction distortion caused by window boundary truncation of the pulse.

[0054] The phase shift of the waveform data in each waveform window is extracted respectively, which can be obtained by comparing the zero-crossing time difference of the received waveform relative to the emitted waveform or the peak position of the correlation function. The phase shift is converted to an angle shift based on the fixed proportional relationship between the phase period and the angle period, and an initial polarization rotation angle is obtained for each window to realize the mapping from the time domain waveform to the spatial domain of the polarization angle, and the microscopic time shift of the continuous waveform is converted to a quantifiable angle.

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

[0056] The initial polarization rotation angles calculated by the continuous multiple waveform windows are sequentially arranged in time sequence to form an angle sequence, and the sequence is subjected to sliding average filtering processing.

[0057] In addition, the initial extinction ratio values calculated by the continuous multiple waveform windows are arranged to form an extinction ratio sequence, and the sequence is subjected to median filtering processing. The median filtering uses a fixed-length window to slide on the sequence, takes the median of the extinction ratio values in each window, and outputs the filtered extinction ratio values, thereby having strong robustness to occasional abnormal pulses, burst interference or accidental measurement errors, and being able to completely remove discrete noise points without affecting normal data distribution, and ensuring the stability of the extinction ratio parameter.

[0058] The present embodiment can establish a strict signal validity screening criterion through the emission-reception time pairing and abnormal delay removal method, fundamentally eliminate the pollution of multipath interference and noise errors on polarization measurement, and guarantee the purity of the data source. In addition, interpolation reconstruction makes up for the information loss caused by discrete sampling, restores the waveform to a state close to the real continuous state, and lays a foundation for high-precision feature extraction. At the same time, the multi-window segmentation strategy converts the continuous data stream into independent analysis units, not only realizes the parallel processing potential, but also avoids boundary truncation errors through periodic integrity constraints. The sliding average filtering of the angle sequence effectively smooths the random disturbance introduced by the high-frequency vibration of the vehicle and optical jitter, so that the polarization rotation angle reflects the inherent properties of the road surface material rather than instantaneous interference. In addition, the median filtering of the extinction ratio sequence makes full use of its strong inhibition ability to sudden noise to prevent abnormal value pollution of the final parameter caused by occasional strong light flicker or detector saturation. The differentiated selection of the two filters reflects the accurate grasp of the noise characteristics of different parameters, the sliding average retains the continuous change trend, and the median removes the discrete impact interference, which together improves the time stability and measurement reliability of the polarization parameters.

[0059] Please refer to Figure 3 In an embodiment of the present application, a lighting device of a laser vehicle lamp is also provided, which comprises: The emission module 31 is configured to control the laser vehicle lamp at the front end of the vehicle to emit a laser beam to irradiate the driving surface in front of the vehicle. The receiving module 32 is configured to receive the reflected light signal of the driving surface, determine the polarization rotation angle and the extinction ratio value of the laser beam according to the reflected light signal of the driving surface, and the extinction ratio value reflects the degree of depolarization of the laser beam caused by the material of the driving surface. The determining module 33 is configured to compare 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. The adjusting module 34 is configured to adjust the lighting mode of the laser vehicle lamp according to the road surface state type.

[0060] The lighting device of the laser vehicle lamp provided by the application directly determines the polarization rotation angle and the extinction ratio by actively irradiating the driving road surface with a laser beam and receiving the reflected light signal, converts the microscopic depolarization characteristics of the road surface material into quantifiable optical parameters, determines the road surface state type after comparison with a preset template, and then adjusts the lighting mode of the laser vehicle lamp, thereby constructing a direct mapping relationship from the polarization modulation characteristics of the road surface material to the lighting control, realizing the perception and feedback of the optical characteristics of the road surface material, accurately matching the adjustment of the lighting mode with the actual optical response characteristics of the road surface material, effectively suppressing adverse optical effects, improving the lighting effectiveness, and avoiding driving safety hazards for the driver.

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

[0062] In one embodiment, the application further provides a storage medium storing computer readable instructions, which, when executed by one or more processors, causes the one or more processors to perform the above-mentioned lighting method of the laser vehicle lamp. The storage medium can be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc.

[0063] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiments can be completed by a computer program instructing related hardware, and the computer program can be stored in a storage medium. When the program is executed, it can include the processes of the above-mentioned embodiments of the method. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), etc.

[0064] Each technical feature of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of each technical feature in the above-mentioned embodiments are not described, but as long as the combination of these technical features does not exist, it should be considered as the scope of the present application.

[0065] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method of illuminating a laser vehicle light, characterized in that The method comprises the following steps: controlling a laser car light at the front end of a vehicle to emit a laser beam to irradiate a driving surface in front of the vehicle; receiving a reflected light signal of the driving surface, determining a polarization rotation angle and an extinction ratio of the laser beam according to the reflected light signal of the driving surface, and the extinction ratio reflecting a degree of depolarization of the driving surface to 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 surface in front of the vehicle; adjusting an illumination mode of the laser car light according to the road surface state type.

2. The method of claim 1, wherein, The laser beam forms linearly polarized light after passing through a polarizer and is reflected after irradiating the driving surface, and an angle generated by a polarization direction of the reflected light relative to an initial polarization direction of the outgoing light is the polarization rotation angle.

3. The method of claim 1, wherein, The laser beam forms linearly polarized light after passing through a polarizer and is reflected after irradiating the driving surface, and the reflected light passes through a polarizer, the polarizer is rotated to a position where a light intensity received by a photodetector is maximum, and a first light intensity value is recorded, then the polarizer is rotated to a position where the light intensity is minimum, and a second light intensity value is recorded, and a ratio of the first light intensity value to the second light intensity value is the extinction ratio.

4. The method of claim 1, wherein, The road surface state type comprises a material type and humidity level information of the driving surface.

5. The method of claim 1, wherein, The adjusting of the illumination mode of the laser car light according to the road surface state type comprises: when the road surface state type is a wet asphalt road surface, reducing an illumination intensity of the laser car light and increasing a divergence angle of the laser beam to a preset value; when the road surface state type is a waterlogged road surface, turning off a blue laser of the laser car light and increasing a horizontal scanning angle of red light and green light to form a fan-shaped light curtain; when the road surface state type is a dry rough road surface, adjusting the laser car light to a standard illumination mode and increasing a power of the laser car light to a standard value.

6. The method of claim 1, wherein, The comparing of the polarization rotation angle and the extinction ratio with the preset template to determine the road surface state type of the driving surface in front of the vehicle comprises: converting the polarization rotation angle into a first voltage signal and converting the extinction ratio into a second voltage signal; inputting the first voltage signal and the second voltage signal into a first input end and a second input end of a parallel comparison array respectively, the parallel comparison array comprising a plurality of comparison units, each of the comparison units internally storing a preset template corresponding to a reference voltage pair, and each of the reference voltage pairs comprising a third voltage signal and a fourth voltage signal; each of the comparison units performing voltage amplitude comparison between the first voltage signal and the third voltage signal and between the second voltage signal and the fourth voltage signal, and when an amplitude difference between the first voltage signal and the third voltage signal is smaller than an amplitude difference between the second voltage signal and the fourth voltage signal, the comparison unit outputs a first level, otherwise, a second level is outputted, wherein output ends of all the comparison units are connected with a judgment unit; the judgment unit only allows a first level with the highest priority to pass at any time, blocks the second level and first levels with other priorities, and encodes the passing first level as the road surface state type.

7. The method of claim 6, wherein, 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.

8. The method of claim 1, wherein, The method comprises the following steps: photoelectric conversion is performed on the reflected light signal to generate an electrical signal sequence; digital sampling is performed on the electrical signal sequence to obtain an original data stream; time sequence alignment and waveform reconstruction are performed on the original data stream, and a Stokes vector component is extracted from the reconstructed waveform data, and a polarization rotation angle and an extinction ratio are calculated based on the Stokes vector component, wherein the Stokes vector component comprises a phase offset and an amplitude value of the waveform data.

9. The method of claim 8, wherein, The method comprises the following steps: a transmission time marker sequence of the laser beam is constructed based on the original data stream, each transmission time marker is paired with a corresponding reception time marker to obtain a marker pair; a time delay value between the marker pairs is calculated, abnormal marker pairs with a time delay value outside a preset interval are removed, and interpolation operation is performed on the remaining marker pairs to obtain waveform data; the waveform data is divided into a plurality of waveform windows, and each waveform window comprises a complete pulse period; a phase offset of the waveform data in each waveform window is extracted, and the phase offset is converted into an angle offset to obtain a plurality of initial polarization rotation angles; a maximum amplitude value and a minimum amplitude value of the waveform data in each waveform window are extracted, and a ratio of the maximum amplitude value to the minimum amplitude value is calculated to obtain a plurality of initial extinction ratios; a plurality of initial polarization rotation angles calculated by a plurality of continuous waveform windows are combined to form an angle sequence, and a sliding average filter is performed on the angle sequence to obtain a polarization rotation angle; a plurality of initial extinction ratios calculated by a plurality of continuous waveform windows are combined to form an extinction ratio sequence, and a median filter is performed on the extinction ratio sequence to obtain an extinction ratio.

10. A lighting device for a laser vehicle lamp, characterized by The method comprises the following steps: a laser light beam is emitted by a laser vehicle lamp at the front end of the vehicle to irradiate a driving surface in front of the vehicle; a reflected light signal of the driving surface is received, and a polarization rotation angle and an extinction ratio of the laser light beam are determined based on the reflected light signal of the driving surface, wherein the extinction ratio reflects the degree of depolarization of the driving surface on the laser light beam; the polarization rotation angle and the extinction ratio are compared with a preset template to determine a road surface state type of the driving surface in front of the vehicle; an illumination mode of the laser vehicle lamp is adjusted based on the road surface state type.

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