Vehicle-mounted camera imaging quality testing method and device suitable for rain and fog scene

Abstract

The invention relates to the field of automobile electronic testing technology and equipment, and discloses a vehicle-mounted camera imaging quality testing method and device suitable for a rain and fog scene, and the method comprises the steps: installing a to-be-tested camera module in a rain and fog environment cabin, setting the spectrum and illumination of a top natural illumination simulation system, and simulating the illumination at different time periods; selecting a test target plate in the darkroom; starting an automatic centering module to align the optical axis with the standard plate reference; rain and fog parameters are set through the environment control host, the rain and fog supply system is started to simulate different levels of rain and fog environments, and the raindrop particle size, concentration, dripping speed, fog visibility and fogdrop particle size are dynamically regulated and controlled; shooting a target plate graph card, extracting characteristic parameters by an image analysis module, performing quantitative analysis, and generating an evaluation report, so as to solve the technical problem of singleness of rain and fog scene environment simulation in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automotive electronic testing technology and equipment, in particular to a kind of vehicle camera imaging quality test method and device suitable for rain and fog scene. BACKGROUND

[0002] With the rapid development of automatic driving technology and advanced driver assistance system (ADAS), vehicle camera has become the core sensor of vehicle environment perception, undertakes the key tasks such as road recognition, obstacle detection, traffic sign recognition. Its imaging quality directly affects the decision accuracy of ADAS system, and then concerns driving safety. However, in the actual driving environment, complex weather conditions such as rain, fog, light mutation will significantly interfere with the camera imaging effect, leading to the decline of target recognition rate, the increase of false detection rate, and even causing system failure. For example, raindrops adhering to the lens surface will cause light scattering, fog particles will cause image blur, and low illumination or backlight environment may cause the signal-to-noise ratio of camera to deteriorate sharply. Therefore, developing a test method and device that can accurately reproduce real rain and fog scenes and quantitatively evaluate the dynamic anti-interference performance of camera has become an urgent need to improve the reliability of ADAS system.

[0003] Current vehicle camera testing technology mainly focuses on static performance evaluation in normal environment, and can only independently adjust rain, fog concentration or light intensity, etc. Single parameter, unable to simultaneously reproduce multi-parameter dynamic coupling scene such as rain, fog, wind speed, light intensity. Unable to simulate real scenes such as dynamic fog diffusion and local concentration mutation. SUMMARY

[0004] The present application aims to provide a kind of vehicle camera imaging quality test method and device suitable for rain and fog scene, to solve the technical problem of single rain and fog scene environment simulation in prior art.

[0005] To achieve the above purpose, the present application adopts the following technical scheme: a kind of vehicle camera imaging quality test method suitable for rain and fog scene, comprising the following steps: Install the camera module to be tested on the module installation platform in the rain and fog environment cabin;Close the rain and fog environment cabin and the dark room box, so that the initial environment is dark environment, and the rain and fog environment cabin and the dark room box are separated by high-transmittance glass;Connect the communication line between the camera module and the image acquisition driving box, and confirm that the camera to be tested can normally light up and transmit images; Set the spectrum and illumination of the natural light simulation system at the top of the rain and fog environment cabin to simulate the light environment at different times of the day; Select the appropriate test target in the dark chamber, move the corresponding target to the center of the camera field of view through the motorized turntable, and provide a standard light source through the parallel light tube light compensation module to compensate for the light environment on the surface of the test target; start the automatic centering module to control the camera optical axis to align with the reference of the test target; Set the target test scene parameter combination through the environmental control host, including raindrop particle size distribution, rainfall intensity, raindrop speed, fog particle size, fog droplet concentration, and local fog movement; start the rain and fog supply system to dynamically control the raindrop particle size, concentration, drop speed, and fog visibility, and fog droplet particle size to simulate different levels of rain and fog environment; In the normal environment without rain and fog and in the set rain and fog environment, the image acquisition drive box drives the camera to shoot the target card respectively, and the image is transmitted to the image analysis module; the image analysis module automatically extracts the feature parameters of the image, performs quantitative analysis, and generates a quantitative evaluation report of the influence of rain and fog interference on imaging quality.

[0006] The principle and advantages of the scheme are: the test method first builds a basic test environment including a rain and fog environment cabin, a dark chamber, etc., and installs and adjusts the to-be-tested camera module. By setting the natural light simulation system parameters to simulate different time periods of light, using the motorized turntable, the parallel light tube light compensation module, and the automatic centering module, the test target is ensured to be in the right position and aligned with the camera optical axis. With the help of the environmental control host, the target test scene parameter combination is set, and the rain and fog supply system is started to dynamically control the rain and fog parameters to simulate different levels of rain and fog environment. Finally, the target card is shot in normal and rain and fog environments respectively, and the evaluation report is generated through module quantitative analysis.

[0007] The problem of single rain and fog scene environment simulation in the prior art is solved, the real rain and fog scene can be accurately reproduced, multi-parameter dynamic coupling scene simulation can be realized, such as simulating dynamic fog diffusion and local concentration mutation, the dynamic anti-interference performance of the camera can be quantitatively evaluated, and the reliability of the ADAS system is improved.

[0008] Preferably, as an improvement, it also includes a raindrop falling speed control method, a laser speed meter is arranged in the rain and fog environment cabin to obtain the instantaneous falling speed of the raindrop, the difference between the measured speed and the preset value is input into the PID controller, and the adjustment instruction is output to the air flow control system; the air flow control system adjusts the air flow speed through the variable frequency fan to change the air resistance of the raindrop, and realizes the control of the raindrop falling speed.

[0009] The improvement has the beneficial effects that: the scheme does not need complex Reynolds number calculation, only 50ms is needed to complete one adjustment cycle, the speed control accuracy is ±0.2m / s, the raindrop falling speed control can be quickly and accurately realized, and the accuracy of raindrop speed simulation is improved.

[0010] Preferably, as an improvement, it also includes a fog environment simulation and control method, which uses piezoelectric ceramic microporous nozzles combined with ultrasonic oscillation technology to generate a group of fog droplets with uniform particle size. A three-dimensional wind field control is provided by a multi-axis guide plate and a variable frequency fan unit to achieve precise guidance of the fog diffusion direction and concentration gradient control. A high-speed camera is used to dynamically capture the movement trajectory of fog droplets, and the droplet size distribution and migration speed are calculated in real time by combining image processing algorithms. The atomization pressure, frequency and airflow speed are dynamically adjusted according to the monitoring data to ensure that the fog visibility and particle size parameters are stable within the target range.

[0011] The benefits of this improvement are: by using multi-sensor fusion and real-time feedback mechanisms, the accuracy of fog particle size control is improved to a higher level, the stability of the falling speed is optimized, and the CV value of fog particle size distribution is reduced. Compared with the traditional open-loop control scheme, the closed-loop system response speed is increased by 3 times, and the parameter attainment time is shortened to within 2 seconds, significantly improving the repeatability and reliability of rain and fog environment simulation.

[0012] Preferably, as an improvement, the raindrop size is adjusted by adjusting the nozzle orifice diameter of the high-pressure spray system; and the raindrop concentration is adjusted by adjusting the spray pressure and frequency of the high-pressure spray system.

[0013] The beneficial effects of this improvement are: it allows for flexible adjustment of raindrop size and concentration, meeting the diverse needs for raindrop parameters under different testing scenarios, and making rain and fog simulation more closely resemble actual complex situations.

[0014] Preferably, as an improvement, a collimator module is installed in front of the test target to provide a standard D65 / D50 light source to simulate a virtual object distance from 400mm to infinity.

[0015] The benefits of this improvement are: it provides a standard D65 / D50 light source, simulates a virtual object distance from 400mm to infinity, provides a stable and standard lighting environment for the test board, ensures the accuracy and consistency of test results, and reduces test errors caused by differences in the lighting environment.

[0016] An imaging quality testing device for vehicle-mounted cameras suitable for rain and fog scenarios, comprising: Darkroom enclosure, providing a dark environment, with an internal basic illuminance of ≤0.1Lux when the darkroom enclosure door is closed; The rain and fog environment chamber is equipped with a high-pressure spray system, a light simulation system, and a high-pressure atomization array on the top, and a rainwater collection device and an airflow control system at the bottom. It can dynamically adjust the raindrop size range, raindrop concentration, dripping speed, fog visibility, fog droplet size, and light conditions. A six-degree-of-freedom attitude adjustment device is used to install a test target plate and a collimator module to precisely adjust the pitch and yaw angles of the target plate relative to the camera. Test target plate module, configure multiple specifications of test target plate, front equipped with parallel light tube module, provide standard light source and simulate virtual object distance; Camera mounting platform, for mounting camera module; High-transmittance glass, between camera and test target plate, transmittance ≥ 95%, rain and fog cabin side equipped with self-cleaning system; Image acquisition drive box, connected with to-be-tested camera and image analysis module through camera communication bus, drive camera to shoot image and transmit to image analysis module; Image analysis module, built-in standard algorithm, quantitatively analyze image and generate quantitative evaluation report.

[0017] The improved beneficial effects are: the overall device works in coordination, provides comprehensive and accurate environment and conditions for testing, can accurately simulate various complex rain and fog scenes, complete camera imaging quality testing, and provide strong basis for improving ADAS system reliability.

[0018] Preferably, as an improvement, the rain and fog environment of the rain and fog environment cabin is provided by a rain and fog supply system, including high-pressure spraying system, high-pressure atomization array device, airflow control system, rain and fog simulation area sensor monitoring system, and closed-loop control is realized through multi-sensor feedback.

[0019] The improved beneficial effects are: closed-loop control is realized through multi-sensor feedback, rain and fog environment parameters can be accurately regulated in real time, the rain and fog environment is ensured to be stable within the target range, and the accuracy and repeatability of testing are improved.

[0020] Preferably, as an improvement, the light simulation system supports D65 / D50 standard light source, simulates light conditions at different times, and the illumination range is 0.1-100 kLux.

[0021] The improved beneficial effects are: the light conditions at different times can be simulated, the testing needs of vehicle-mounted camera under various light environments are met, and the imaging quality of camera under different light is comprehensively evaluated.

[0022] Preferably, as an improvement, the image analysis module establishes a mapping relationship model of rain and fog environment parameters and imaging indicators, and outputs a quantitative evaluation report including MTF decline rate, color restoration degree change, and signal-to-noise ratio attenuation key indicators.

[0023] The improved beneficial effects are: the influence of rain and fog environment on camera imaging quality can be intuitively presented, which provides clear direction for researchers to optimize camera performance, and helps to improve the imaging quality of camera in rain and fog scenes.

[0024] Preferably, as an improvement, the sensor monitoring system of the rain and fog simulation area comprises 12 monitoring points arranged along the edges of the cuboid, and real-time collection of raindrop particle size, falling speed and rainwater mixing ratio.

[0025] The improvement has the beneficial effects that the 12 monitoring points arranged along the edges of the cuboid can comprehensively and real-timely collect data such as raindrop particle size, falling speed and rainwater mixing ratio, provide detailed and accurate information for accurate simulation and regulation of the rain and fog environment, and improve the reliability and accuracy of the test. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The flowchart of the embodiment of the present application.

[0027] Figure 2 The overall structure schematic diagram of the device of the embodiment of the present application.

[0028] Figure 3 The structure schematic diagram of the rain and fog environment cabin.

[0029] Figure 4 The monitoring point distribution schematic diagram in the rain and fog environment cabin.

[0030] The reference signs in the drawings of the specification include: darkroom box 1, rain and fog environment cabin 2, high-pressure spraying system 3, high-pressure atomization array 4, six-degree-of-freedom attitude adjustment device 5, camera mounting platform 6, high-transmittance glass 7, monitoring point 8, air flow control system 9, rainwater collection device 10, light simulation system 11 and air supply pipe 12. DETAILED DESCRIPTION

[0031] The following will be further described in detail through specific embodiments: EMBODIMENT As shown in the accompanying drawings, Figure 1 A vehicle-mounted camera imaging quality test method suitable for rain and fog scenes, comprising: Install the camera module to be tested on the six-degree-of-freedom module mounting platform in the rain and fog environment cabin, and perform necessary debugging to ensure its normal operation.

[0032] The rain and fog environment cabin and the darkroom box are in a closed state, and the darkroom box provides a dark environment for the rain and fog environment cabin to isolate the influence of external natural light on the test (the internal basic illumination is ≤0.1 Lux). The rain and fog environment cabin and the darkroom box are separated by high-transmittance glass with self-cleaning function, to ensure that the glass transmittance is maintained above 95%.

[0033] Connect the communication line of the camera module and the image acquisition drive box, and confirm through the image analysis module that the camera to be tested can normally light up and transmit images. If it cannot normally light up or transmit, the installation and communication connection of the camera module need to be adjusted again.

[0034] The spectrum and illumination of the natural light simulation system on the top of the rain and fog environment chamber are set to simulate the light environment at different times of the day. A suitable test target (such as an ISO 12233 beveled test target, an SFR test target, a gray scale target, etc.) is selected, and the corresponding test target is moved to the center of the field of view of the camera by a motorized turntable. A standard D65 / D50 light source is provided by a parallel light tube light compensation module to compensate for the light environment on the surface of the test target.

[0035] The automatic centering module is started, and a laser positioning and visual feedback composite positioning technology is used to control the six-degree-of-freedom platform to complete the reference alignment of the optical axis of the camera and the test target. The pitch angle (±90°) and the yaw angle (±90°) of the test target relative to the camera are accurately controlled. The target test scene parameter combination is set by the environment control host, including raindrop particle size distribution, rainfall intensity, raindrop speed, fog particle size, fog droplet concentration, and local fog movement.

[0036] The rain and fog supply system is started, including a high-pressure spraying system and a high-pressure atomization array device, combined with an air flow control system and a rain and fog simulation area sensor monitoring system, to dynamically control the raindrop particle size, concentration, drop speed, and fog visibility, fog droplet size, and other parameters to simulate different levels of rain and fog environment. In the normal environment without rain and fog, the image acquisition drive box is controlled to drive the camera to take pictures of the test target, the initial state image is obtained and transmitted to the image analysis module, and is used for comparison and analysis with the imaging quality in the subsequent rain and fog environment.

[0037] In the set rain and fog environment, the environment simulation system and the image acquisition drive box are triggered synchronously, the test images under different environmental conditions are collected according to the preset time sequence, and are transmitted to the image analysis module.

[0038] The image analysis module automatically extracts the resolving power (MTF), signal-to-noise ratio (SNR), white balance error, dynamic range, and other characteristic parameters of the image, and performs quantitative analysis according to the general standard method (such as ISO 12233, ISO 16505, etc.).

[0039] According to the image analysis results, a quantitative evaluation report of the influence of rain and fog interference on the imaging quality is generated, including the imaging data analysis results under different rain and fog levels, light conditions, and attitude positions. The report can include key indicators such as MTF drop rate, color restoration degree change, and signal-to-noise ratio attenuation, which are used to evaluate the anti-interference performance and imaging quality of the camera in the rain and fog environment.

[0040] Through the above process, the rain and fog and other harsh weather conditions can be accurately simulated to comprehensively evaluate the imaging quality of the vehicle-mounted camera, provide strong support for the development of the camera module, and ensure the accuracy and repeatability of the test.

[0041] The rain simulation is realized by the high-pressure spraying system on the top of the environmental cabin, the rain and mist simulation area sensor monitoring system, the air flow control system and the rain and mist control system, forming a closed-loop control system based on multi-sensor feedback. The high-pressure spraying system uses high-precision adjustable nozzles to support dynamic adjustment of raindrop particle size (0.5-5 mm) and flow rate (10-200 drops / min), and realizes accurate output of raindrop generation parameters through coordinated control of nozzle aperture and spraying pressure.

[0042] The multi-sensor monitoring network is arranged at 12 monitoring points on the edges of the rain and mist area, i.e. 3 monitoring points at both ends and in the middle of the long side of the cuboid, 2 monitoring points at both ends of the short side and high side of the cuboid, integrating laser speed meters and raindrop particle size analyzers to collect raindrop particle size, falling speed and rainwater mixing ratio in real time, the rainwater mixing ratio being the rainwater mass in unit volume of air, g / m3. A three-dimensional environmental parameter perception matrix is formed.

[0043] The PID feedback control mechanism is built into the rain and mist control system, with the preset rainfall parameter as the target value, and the nozzle aperture, spraying pressure and air flow compensation strength are dynamically adjusted by comparing the real-time feedback data of the sensors.

[0044] When the deviation of the raindrop falling speed is monitored, the system adjusts the flow rate and direction of the vertical controllable air flow to compensate for the influence of air resistance on the movement of the raindrops, ensuring that the falling speed error is ≤5%.

[0045] The resistance wind control optimization is realized by the air flow control system in combination with the fluid mechanics model, through the guide plate and variable frequency fan to dynamically match the air flow resistance of the raindrop falling path, eliminate turbulence interference and ensure the uniformity of rainfall distribution (spatial deviation ≤8%).

[0046] The rainfall parameter is equivalent to the total height of ground rainwater per hour (mm) defined by the meteorological department, which is converted into three controllable variables: raindrop particle size, falling quantity and speed in the simulation cabin. Through the stepwise adjustment of the nozzle aperture (0.5-5 mm range) combined with the spraying frequency control, the simulation of different rainfall levels (light rain / medium rain / heavy rain) is realized.

[0047] The rainfall mathematical model and closed-loop verification are based on the simplified relationship R=qr×vr (R is the rainfall, qr is the rainwater mixing ratio, and vr is the raindrop falling speed). The system verifies the deviation between the calculated value and the preset value in real time through the mass flow meter and the laser speed meter, and triggers the PID regulator to correct the spraying parameters.

[0048] For example, when it is monitored that the actual rainfall is 10% lower than the target value, the system simultaneously increases the nozzle aperture and the spraying pressure, and fine-tunes the air flow speed to maintain the stability of the terminal speed of the raindrops. ​

[0049] Closed-loop control method for raindrop falling speed: The formula for the relationship between raindrop falling speed and the actual falling speed is used only as a reference. The formula for the relationship between raindrop falling speed and the actual falling speed is: ; in, d is the falling velocity of the raindrop; d is the diameter of the raindrop (unit: meter, m). The density of water (1000 kg / m³) ); The density of air (a constant, approximately 1.2 kg / m³) ); ρ is the drag coefficient (related to raindrop shape and Reynolds number); g is the acceleration due to gravity (9.8 m / s²). ).

[0050] In actual control, a simplification strategy is adopted: Real-time monitoring with laser velocimeters: Non-contact laser velocimeters are deployed at monitoring points to directly obtain the instantaneous falling speed of raindrops; Deviation feedback adjustment: The difference between the measured speed and the preset value is input into the PID controller, and the adjustment command is output to the airflow control system; Dynamic resistance compensation: By rapidly adjusting the airflow speed (0-10m / s adjustable) through a variable frequency fan, the air resistance experienced by raindrops is changed, achieving closed-loop speed correction.

[0051] This scheme does not require complex Reynolds number calculations and can complete an adjustment cycle in just 50ms, with a speed control accuracy of ±0.2m / s.

[0052] Closed-loop control optimization for fog environment simulation Fog simulation achieves precise control through high-pressure atomization arrays, dynamic monitoring, and feedback adjustment. High-precision atomizing nozzle: It adopts a piezoelectric ceramic microporous nozzle (orifice diameter adjustable from 1-50μm) and combines ultrasonic oscillation technology to generate a group of droplets with uniform particle size; Three-dimensional wind field control: Through multi-axis guide vanes and variable frequency fan units, precise guidance of the diffusion direction of fog (angle deviation ≤3°) and concentration gradient control are achieved; High-speed camera dynamic monitoring: Capture the movement trajectory of fog droplets at a frame rate of 200fps, and combine image processing algorithms to calculate the fog droplet size distribution (CV value ≤15%) and migration speed in real time; Adaptive feedback adjustment: Dynamically adjusts atomization pressure (0.1-2MPa), frequency (1-10kHz), and airflow velocity (0.5-5m / s) based on monitoring data to ensure that fog visibility (10-1000m) and particle size parameters remain stable within the target range.

[0053] Closed-loop feedback control, through multi-sensor fusion and real-time feedback mechanism, improves the control accuracy of raindrop particle size to ±0.1mm, optimizes the stability of falling speed to ±2%, and reduces the CV value of fog particle size distribution to 12%. Compared with the traditional open-loop control scheme, the response speed of the closed-loop system is increased by 3 times, the parameter compliance time is shortened to 2 seconds, and the repeatability and reliability of the rain and fog environment simulation are significantly improved.

[0054] As shown in Figs. 1-3, a vehicle-mounted camera imaging quality test device suitable for rain and fog scenes includes: Figure 2 , Figs. 1-3, a vehicle-mounted camera imaging quality test device suitable for rain and fog scenes includes: Figure 3 , Figs. 1-3, a vehicle-mounted camera imaging quality test device suitable for rain and fog scenes includes: Figure 4 , Figs. 1-3, a vehicle-mounted camera imaging quality test device suitable for rain and fog scenes includes: Darkroom box 1 provides a dark environment. When the hatch of the darkroom box 1 is closed, the internal basic illumination is ≤0.1Lux, and the external natural light is isolated. The light conditions of the test environment are controllable, and the influence of background light on imaging quality is avoided.

[0055] Rain and fog environment cabin 2 is provided with high-pressure spraying system 3 for simulating rain environment, light simulation system 11 for simulating scene environment light, and high-pressure atomization array 4 for simulating fog environment at the top. Rainwater collecting device 10 and air flow control system 9 are arranged at the bottom of rain and fog environment cabin 2.

[0056] The dynamic controllable parameters of rain and fog environment cabin 2 include: Raindrop particle size range: 0.5-5mm, realized by adjusting the nozzle aperture of high-pressure spraying system 3.

[0057] Raindrop concentration: 10-200 drops / m2, realized by controlling the spraying pressure and frequency of high-pressure spraying system 3.

[0058] Dropping speed: 2-20m / s, realized by compensating the vertical air resistance of raindrop falling path combined with air flow control system 9.

[0059] Fog visibility: 10-1000m, realized by generating fine fog droplets through high-pressure micro-nozzle in high-pressure atomization array 4, forming high-concentration fog clusters by multi-nozzle array, and then controlling the wind field by air flow control system 9.

[0060] Fog droplet size: 1-50μm, realized by adjusting the aperture of piezoelectric ceramic micro-nozzle.

[0061] Light simulation: The top is configured with light simulation system 11 (0.1-100kLux) with adjustable spectrum and illumination, which can reproduce all-weather environment light.

[0062] ​The six-DOF attitude adjustment device 5, located in the dark chamber, is used to install the test target and collimator module. It achieves spatial self-alignment between the camera and the target via an electric turntable. It precisely adjusts the pitch angle (±90°) and yaw angle (±90°) of the target relative to the camera, supporting automated testing at multiple angles.

[0063] The test chart module is equipped with ISO12233 bevel test charts, SFR test charts, grayscale charts, and dynamic range test patterns. A collimator module is mounted in front of the charts, providing a standard D65 / D50 light source to simulate virtual object distances from 400mm to infinity. A motorized turntable allows for quick chart changes to adapt to different testing needs.

[0064] The collimator module compensates for the ambient light on the test target surface, ensuring uniform illumination and supporting virtual object distance simulation. It eliminates ambient light interference, improving the accuracy of image quality analysis.

[0065] The camera mounting platform 6 is used to install the camera module. The camera mounting platform 6 is installed inside the rain and fog environment chamber 2 and is set opposite to the test target module. The rain and fog supply system, such as the high-pressure spray system 3, the light simulation system 11, and the high-pressure atomization array 4, is located between the test target module and the camera mounting platform 6.

[0066] High-transmittance glass 7, positioned between the camera and the test panel, isolates the darkroom and the rain / fog environment chamber 2. Its light transmittance is ≥95%. The high-transmittance glass 7 on the rain / fog chamber side is equipped with a self-cleaning system to prevent water droplets from adhering and affecting imaging.

[0067] The image acquisition driver box is connected to the camera under test and the image analysis module via the camera communication bus.

[0068] It drives the camera to capture images and transmits them to the image analysis module, supporting adjustments to parameters such as exposure time and gain.

[0069] The image analysis module incorporates standard algorithms such as ISO12233 and ISO16505 and supports custom analysis methods. It is used to analyze and quantitatively evaluate indicators such as MTF (Mean Transmission Factor), Signal-to-Noise Ratio (SNR), White Balance Error, and Dynamic Range. It establishes a mapping model between rain and fog environmental parameters and imaging indicators, and outputs a quantitative evaluation report.

[0070] The rain and fog environment of the rain and fog environment chamber 2 is provided by the rain and fog supply system, which includes a high-pressure spray system 3, a high-pressure atomization array 4, an airflow control system 9, and a rain and fog simulation area sensor monitoring system.

[0071] The rain and fog simulation area sensor monitoring system includes 12 monitoring points arranged along the edge of a cuboid to collect raindrop particle size, falling velocity, and rainwater mixing ratio in real time.

[0072] The rain and fog supply system provides dynamic adjustment of nozzle aperture, spray pressure and air flow intensity according to the deviation between the measured value and the preset value, to ensure parameter stability.

[0073] The air flow control system 9 adjusts the air flow resistance of the raindrop falling path through the guide plate and the variable frequency fan, and eliminates turbulence interference. The air flow generated by the variable frequency fan is connected to the rain and fog environment cabin 2 through the air supply pipe 12, and the guide plate is arranged at the outlet end of the air supply pipe 12 to realize wind direction adjustment. A wind speed sensor is arranged at the outlet of the air supply pipe 12 to ensure the uniformity of rainfall distribution (spatial deviation ≤8%) and improve the simulation accuracy. The variable frequency fan also includes a wind power device and a drying device, which provides three-dimensional wind field control, and adjusts the fog concentration through humidity adjustment.

[0074] The light simulation system 11 supports D65 / D50 standard light sources and simulates light conditions at different times (such as noon and dusk). The illumination range is 0.1-100 kLux, covering night to strong light environment.

[0075] The device provides an automatic test process: Fix the camera module to be tested on the camera mounting platform 6, and confirm that the communication and image transmission are normal. Input the target values such as raindrop size, rainfall intensity, fog concentration and light conditions through the control host. Select the test target type, and complete the reference alignment of the camera and the target plate through the six-degree-of-freedom platform. Trigger the rain and fog environment and image acquisition module, acquire images according to the preset time sequence, automatically extract feature parameters and generate a report.

[0076] Example 1: MTF and defocus performance test under rain interference Environmental parameter setting, Raindrop parameters: particle size 2mm (adjusted by high-pressure spray system nozzle aperture), rainfall intensity 100 drops / (unit volume of air raindrop quantity), falling speed 8m / s (stabilized after air resistance compensation by air flow control system).

[0077] Lighting conditions: 20kLux (provided by the light simulation system at the top of the rain and fog cabin, simulating overcast environment).

[0078] Temperature and humidity control: cabin temperature 25℃±1℃, humidity 85%±5% (to avoid water vapor condensation interference).

[0079] Test target and object distance simulation, Target type: ISO12233 beveled test target (for MTF analysis).

[0080] Object distance simulation: generate virtual object distances of 0.5m, 1m, 1.5m, 2m, 2.5m and 3m through the collimator module (light path folding technology is used).

[0081] Camera pose and field of view control, Automatic centering: Start the laser positioning and visual feedback composite module to control the six-degree-of-freedom platform to complete the alignment of the camera optical axis and the reference plate benchmark (error ≤ 0.05°).

[0082] Field of view coverage: Set the six-degree-of-freedom device to capture 10%~70% of the field of view (interval 10%), and evaluate the impact of defocus on edge imaging.

[0083] Test procedure, environmental simulation system (raindrops + light) and image acquisition drive box are started according to the preset timing (delay ≤ 50ms). Take the average of 10 consecutive images after removing outliers.

[0084] Analysis indicators, MTF decline rate: Compare the MTF50 value in the rain-free scene to calculate the attenuation ratio in the rainy environment.

[0085] Defocus curve: Draw the MTF value change at different object distances to locate the best focus distance offset.

[0086] Output report, generate a quantitative report (CSV+PDF format) containing MTF attenuation curve, defocus amount statistics, and environmental parameter correlation.

[0087] Example 2: Color restoration performance test in dense fog environment Fog parameters, Concentration gradient: 100m, 300m, 500m, 800m, 1000m visibility (adjusted by high-pressure atomization array and air flow control system).

[0088] Fog droplet size: 10~30μm (monitored and adjusted in real time by laser particle size instrument).

[0089] Lighting conditions: 5kLux (low light simulation of morning mist environment).

[0090] Test board and pose control, Board type: 24-color standard color card (complies with ISO18312-1 standard).

[0091] Pose simulation: Set the camera yaw angle to ±30° through the six-degree-of-freedom platform (simulate vehicle tilt scenarios).

[0092] Image acquisition and processing, White balance calculation: Calculate the color temperature deviation (ΔT = target color temperature - measured color temperature) by collecting the average of the RGB three channels.

[0093] Color restoration degree: Compare the standard color card and the measured image E value (CIEDE2000 algorithm).

[0094] Dynamic range: Assess the impact of haze on highlight / shadow details by gray scale target.

[0095] Test procedure, Gradient test: Test from low to high visibility, collect data after each interval is stable for 5 minutes.

[0096] Repeatability verification: Repeat the test 3 times for each interval of visibility, and calculate the standard deviation (σ≤2%).

[0097] Output report, generate a comparative report containing color temperature deviation curve, E value distribution and dynamic range attenuation, mark the key visibility threshold (such as E>5 visibility value).

[0098] The above is only an embodiment of the present application, and the specific technical solutions and / or common knowledge of the scheme are not described in detail. It should be noted that for those skilled in the art, without departing from the technical solutions of the present application, a number of modifications and improvements can be made, which should also be considered as the protection scope of the present application, which will not affect the effect and practicality of the present application. The protection scope of the present application should be subject to the content of its claims, and the specific implementation mode and the like recorded in the specification can be used to explain the content of the claims.

Claims

1. A method for testing imaging quality of a vehicle-mounted camera in a rain and fog scene, characterized in that, The method comprises the following steps: Install the camera module to be tested on the module installation platform in the rain and fog environment cabin; close the rain and fog environment cabin and the darkroom box, so that the initial environment is a dark environment, and the rain and fog environment cabin and the darkroom box are separated by high-transmittance glass; connect the communication line between the camera module and the image acquisition driving box, and confirm that the camera to be tested can normally light up and transmit images; Set the spectrum and illuminance of the natural light simulation system at the top of the rain and fog environment cabin to simulate the light environment at different times of the day; Select a suitable test target in the darkroom box, move the corresponding target to the center of the camera field of view through the electric turntable, and provide a standard light source through the parallel light tube light compensation module to compensate for the light environment on the surface of the test target; Start the automatic centering module to control the alignment of the camera optical axis and the reference of the test target; Set the target test scene parameter combination through the environment control host, including raindrop particle size distribution, rainfall intensity, raindrop speed, fog particle size, fog droplet concentration, and local fog movement; Start the rain and fog supply system to dynamically control the raindrop particle size, concentration, drop speed, and fog visibility and fog droplet size to simulate different levels of rain and fog environment; In the normal environment without rain and fog and in the set rain and fog environment, control the image acquisition driving box to drive the camera to shoot the target card to obtain images and transmit them to the image analysis module; the image analysis module automatically extracts the feature parameters of the images, performs quantitative analysis, and generates a quantitative evaluation report of the influence of rain and fog interference on imaging quality.

2. The method for testing the imaging quality of a vehicle-mounted camera suitable for rain and fog scenes according to claim 1, characterized in that, The method also includes a raindrop falling speed control method, a laser speed meter is arranged in the rain and fog environment cabin to obtain the instantaneous falling speed of the raindrop, the difference between the measured speed and the preset value is input into a PID controller, and an adjustment instruction is output to an air flow control system; the air flow control system quickly adjusts the air flow speed through a variable frequency fan to change the air resistance experienced by the raindrop, thereby realizing raindrop falling speed control.

3. The method for testing the imaging quality of a vehicle-mounted camera suitable for rain and fog scenes according to claim 2, characterized in that, The method also includes a fog environment simulation control method, a piezoelectric ceramic micro-hole nozzle is used to generate a fog droplet group with uniform particle size in combination with ultrasonic oscillation technology, a multi-axis guide vane and a variable frequency fan set are used to provide three-dimensional wind field control to realize accurate guidance of the diffusion direction of the fog and concentration gradient control; a high-speed camera is used to dynamically capture the motion trail of the fog droplet, and an image processing algorithm is used to calculate the fog droplet particle size distribution and migration speed in real time; the atomization pressure, frequency, and air flow speed are dynamically adjusted according to the monitoring data to ensure that the fog visibility and particle size parameters are stably within the target range.

4. The method for testing the imaging quality of a vehicle-mounted camera suitable for rain and fog scenes according to claim 3, characterized in that: The raindrop particle size is adjusted by adjusting the nozzle aperture of the high-pressure spraying system, and the raindrop concentration is adjusted by adjusting the spraying pressure and frequency of the high-pressure spraying system.

5. The method for testing the imaging quality of a vehicle-mounted camera suitable for rain and fog scenes according to claim 4, characterized in that: A parallel light tube module is installed in front of the test target to provide a standard D65 / D50 light source to simulate a virtual object distance of 400 mm to infinity.

6. A device for testing the imaging quality of a vehicle-mounted camera in a rain and fog scene, using the test method of any one of claims 1-5, characterized in that, The method comprises the following steps: The darkroom box provides a dark environment, and the internal basic illuminance is less than or equal to 0.1 Lux when the cabin door of the darkroom box is closed; The rain and fog environment cabin is provided with a high-pressure spraying system, a light simulation system, and a high-pressure atomization array at the top, and is provided with a rainwater collection device and an air flow control system at the bottom, and can dynamically control the raindrop particle size range, raindrop concentration, drop speed, fog visibility, fog droplet size, and light conditions; Six-degree-of-freedom attitude adjustment device for mounting test target and collimator module, to accurately adjust the pitch angle and yaw angle of the test target relative to the camera; Test target module, equipped with multiple specifications of test targets, with a collimator module in front to provide standard light source and simulate virtual object distance; Camera mounting platform for mounting camera module; High-transmittance glass between camera and test target, transmittance ≥ 95%, with self-cleaning system on the side of the rain and fog chamber; Image acquisition drive box connected to the camera under test and image analysis module through camera communication bus, to drive the camera to take pictures and transmit them to the image analysis module; Image analysis module with built-in standard algorithms for quantitative analysis of images and generation of quantitative evaluation report.

7. The device for testing the imaging quality of vehicle-mounted camera suitable for rain and fog scenes according to claim 6, characterized in that: The rain and fog environment of the rain and fog environment chamber is provided by a rain and fog supply system, including a high-pressure spraying system, a high-pressure atomization array device, an airflow control system, and a rain and fog simulation area sensor monitoring system, which realizes closed-loop control through multi-sensor feedback.

8. The method and device for testing the imaging quality of vehicle-mounted cameras suitable for rain and fog scenes according to claim 7, characterized in that: The light simulation system supports D65 / D50 standard light source and simulates different periods of light conditions, with an illuminance range of 0.1-100 kLux.

9. The device for testing the imaging quality of a vehicle-mounted camera suitable for rain and fog scenes according to claim 8, characterized in that: The image analysis module establishes a mapping relationship model between rain and fog environment parameters and imaging indicators, and outputs a quantitative evaluation report including MTF decline rate, color restoration degree change, and signal-to-noise ratio attenuation key indicators.

10. The device for testing the imaging quality of vehicle-mounted camera suitable for rain and fog scenes according to claim 9, characterized in that: The sensor monitoring system of the rain and fog simulation area includes 12 monitoring points arranged along the edges of the cuboid, which real-time collects raindrop particle size, falling speed, and rainwater mixing ratio.

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