System for detecting tail gas of vehicle

Abstract

The utility model discloses a system for detecting tail gas of a vehicle. The system comprises a detection light emitting unit used for emitting detection light, and the detection light is modulated light loaded with sinusoidal signals; the signal detection unit is in communication connection with the detection light emitting unit and is used for receiving the detection light and generating a corresponding electric signal according to the detection light; and the data processing unit is in communication connection with the signal detection unit and is used for receiving the electric signal, generating a corresponding analog signal according to the electric signal and determining the light impermeability of the tail gas of the vehicle according to the analog signal. According to the system provided by the invention, the shielding objects of non-tail gas particles in the tail gas can be identified through the sinusoidal signal loaded by the detection light, so that the measurement precision is improved, and the reliability of a detection result is enhanced.

Description

Technical Field

[0001] The present disclosure generally relates to the field of motor vehicle exhaust detection technology. More specifically, the present disclosure relates to a system for detecting vehicle exhaust. Background Art

[0002] In the detection of road traffic emissions, the opacity of exhaust gas is often used as an important indicator to evaluate motor vehicle pollution emissions. The opacity of exhaust gas refers to the degree to which particulate matter (such as smoke) in the exhaust gas blocks light, and can be used to detect and monitor whether the exhaust pollution emissions of motor vehicles meet environmental protection standards.

[0003] In the existing technology, the opacity of the exhaust gas of the target traveling on the road can be detected by remote sensing detection method. Specifically, the remote sensing detection method is based on the optical principle, and determines the opacity of the exhaust gas by emitting a light source and measuring the degree of absorption of the light after passing through the exhaust plume. This method can be performed without affecting traffic. However, the traditional remote sensing detection method cannot effectively distinguish obstructions, or cannot accurately remove obstructions with a diameter smaller than the spot diameter, thereby affecting the accuracy of the measurement data.

[0004] In view of this, there is an urgent need to provide an innovative system for detecting vehicle exhaust gas, so as to improve the accuracy of exhaust gas detection and strengthen the control of motor vehicle pollution emissions. Utility Model Content

[0005] In order to at least solve one or more of the technical problems mentioned above, the present disclosure proposes a system for detecting vehicle exhaust.

[0006] In a first aspect, the present disclosure provides a system for detecting vehicle exhaust, comprising: a detection light emitting unit, which is used to emit detection light, wherein the detection light is a modulated light loaded with a sinusoidal signal; a signal detection unit, which is communicatively connected to the detection light emitting unit, and is used to receive the detection light and generate a corresponding electrical signal based on the detection light; and a data processing unit, which is communicatively connected to the signal detection unit, and is used to: receive the electrical signal; generate a corresponding analog signal based on the electrical signal; and determine the opacity of the vehicle exhaust based on the analog signal.

[0007] In some embodiments, the system described in the first aspect of the present disclosure further includes a reflection device, wherein the reflection device is used to change the optical path of the detection light to detect the vehicle exhaust located at different positions.

[0008] In some further embodiments, the reflecting device includes a first reflecting device, wherein the first reflecting device is used to change the optical path of the detection light so that the detection light is received by the signal detection unit after passing through the first reflecting device to detect the vehicle exhaust gas located between the detection light emitting unit and the first reflecting device and / or between the first reflecting device and the signal detection unit.

[0009] In some further embodiments, the reflecting device also includes a second reflecting device, wherein the second reflecting device is used to change the optical path of the detection light passing through the first reflecting device, so that the detection light is received by the signal detection unit after passing through the second reflecting device, so as to detect the vehicle exhaust located between the first reflecting device and the second reflecting device and / or between the second reflecting device and the signal detection unit.

[0010] In some further embodiments, the detection light emitting unit loads a sinusoidal signal to the detection light in a variable power manner.

[0011] In some further embodiments, a cross-sectional area of ​​the detection light in any direction is larger than a cross-sectional area of ​​the exhaust gas.

[0012] In some further embodiments, the reflecting device comprises a reflecting mirror and an adjusting frame, wherein the reflecting mirror is disposed on the adjusting frame so that the height and / or angle of the reflecting mirror can be adjusted through the adjusting frame.

[0013] In some further embodiments, the second detected light data further includes exhaust gas diffusion data, and the method further includes: detecting a diffusion speed of the vehicle exhaust gas according to the exhaust gas diffusion data.

[0014] In some further embodiments, the system described in the first aspect of the present disclosure further includes a vehicle speed detection unit, wherein the vehicle speed detection unit is communicatively connected to the detection light emitting unit and is used to detect the speed of the vehicle to control the emission time of the detection light emitting unit to emit the detection light.

[0015] In some further embodiments, the system described in the first aspect of the present disclosure further includes a vehicle identification unit, wherein the vehicle identification unit is used to identify the vehicle so as to bind the detection result of the vehicle exhaust gas to the vehicle.

[0016] Through the system for detecting vehicle exhaust as provided above, the disclosed embodiment can effectively distinguish between obstructions and exhaust by detecting the detection light loaded with a sinusoidal signal emitted by the detection light emitting unit. Furthermore, the disclosed embodiment also changes the optical path of the detection light through the reflection device so that the detection light can pass through the exhaust located at different positions, thereby enhancing the flexibility of system layout. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] By reading the detailed description below with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present disclosure will become readily understood. In the accompanying drawings, several embodiments of the present disclosure are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0018] Figure 1 A schematic diagram of an exemplary exhaust gas detection system applicable to the embodiment of the present disclosure is shown;

[0019] Figure 2 An exemplary flow chart showing a vehicle exhaust gas detection method according to some embodiments of the present disclosure;

[0020] Figure 3 A schematic diagram showing a process of screening valid data in the second detection light data according to some embodiments of the present disclosure is shown;

[0021] Figure 4 An exemplary flow chart showing a method for determining the opacity of exhaust gas according to some embodiments of the present disclosure;

[0022] Figure 5 A schematic block diagram of an electronic device according to some embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.

[0024] It should be understood that the terms "include" and "comprising" used in the specification and claims of the present disclosure indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0025] It should also be understood that the terms used in this disclosure are only for the purpose of describing specific embodiments and are not intended to limit the disclosure. As used in this disclosure and claims, the singular forms of "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be further understood that the term "and / or" used in this disclosure and claims refers to any combination of one or more of the associated listed items and all possible combinations, including these combinations.

[0026] As used in this specification and claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0027] The specific implementation of the present disclosure is described in detail below with reference to the accompanying drawings.

[0028] In traditional exhaust gas opacity detection, the light source of the detection light is usually driven by a constant current, that is, a constant current source is given to the light source, and the intensity of the detection light output by the light source is constant. When the detection light passes through exhaust gas with different particle concentrations, it will produce different degrees of absorption, that is, the opacity of the exhaust gas is different; therefore, the concentration of particulate matter in the exhaust gas can be determined based on the opacity of the exhaust gas, and then the pollution level of the exhaust gas can be evaluated. However, when there are other non-exhaust particulate obstructions such as thin wires and ropes in the exhaust gas, light absorption will also occur, so that the opacity of other non-exhaust particulate obstructions such as thin wires and ropes will interfere with the opacity of the exhaust gas, and the opacity of the exhaust gas puff cannot be accurately known, affecting the reliability of the detection data.

[0029] In view of this, the embodiments of the present disclosure provide a vehicle exhaust gas detection method, an electronic device and a computer-readable storage medium, which can filter out valid data in the second detection light data through the first detection light data of the time period when the vehicle has not passed and the second detection light data of the time period when the vehicle has passed, and can effectively distinguish other obstructions of non-exhaust particles in the exhaust gas puff, thereby improving the reliability of the exhaust gas detection data.

[0030] Figure 1 A schematic diagram of an exemplary exhaust gas detection system applicable to the embodiment of the present disclosure is shown.

[0031] like Figure 1 As shown, the exhaust gas detection system includes a detection light emitting unit 110, a reflection device 120 and a signal detection unit 130. The working section 140 is any section of the road paved by the exhaust gas detection system, the road target 150 is any vehicle traveling in front of the working section, the exhaust gas 160 is the exhaust gas emitted by the road target 150, and the detection light 170 is the detection light emitted by the detection light emitting unit 110. For ease of understanding, Figure 1 The front shown in FIG. 1 is the driving direction of the road target 150. It should be noted that the exhaust gas detection system in the embodiment of the present disclosure is illustrative and not restrictive.

[0032] The detection light emitting unit 110 is used to emit the detection light 170, wherein the detection light 170 is a modulated light loaded with a sinusoidal signal. Specifically, the detection light emitting unit 110 can be any device capable of emitting a detection light 170 of a certain wavelength, and it can modulate the light source by, for example, directly changing the output of the light source, or coupling with a modulator such as an electro-optic modulator, an acousto-optic modulator, etc., so as to load the detection light with a sinusoidal signal, so that the energy of the detection light changes periodically with the sinusoidal signal. Further, the detection light emitting unit 110 can be set at a position close to the exhaust gas height on either side of the working section 140, without the need for a gantry or other device to be set above the road, so that the layout cost is lower. The specific setting position can be adjusted according to the application scenario, and the present disclosure is not limited in this regard. Furthermore, the wavelength of the detection light 170 can be selected according to the actual application scenario, the scattering and absorption characteristics of light of different wavelengths on particulate matter, and other conditions; preferably, the present disclosure embodiment uses green light with a wavelength of 510nm to ensure that the detection light 170 can effectively penetrate the particulate matter therein and provide more accurate measurement results.

[0033] The signal detection unit 130 is in communication connection with the detection light emitting unit 110, and is used to receive the detection light 170 and generate a corresponding electrical signal according to the detection light 170. The signal detection unit 130 may include a photoelectric conversion module therein, which is used to generate a corresponding electrical signal according to the received detection light 170, and is used to indicate the light intensity of the detection light 170 reaching the signal detection unit 130.

[0034] The reflecting device 120 is used to change the optical path of the detection light 170 to detect vehicle exhaust gas at different positions. The reflecting device 120 may include a reflector and an adjustment frame, wherein the reflector may be arranged on the adjustment frame so that the height and / or angle of the reflector can be adjusted by the adjustment frame. Further, since the positions where different vehicles discharge exhaust gas may be different, in order to allow the detection light 170 to pass through exhaust gas at different positions, the reflecting device 120 may include multiple reflecting devices.

[0035] Furthermore, as described above, the detection light emitting unit 110 can be arranged at different positions, and therefore, the reflective device 120 can adaptively adjust the arrangement position and quantity so that the detection light 170 passes through the exhaust gas. For example, in one embodiment, the reflective device 120 may include a first reflective device, wherein the first reflective device is used to change the optical path of the detection light 170, so that the detection light 170 is received by the signal detection unit 130 after passing through the first reflective device, so as to detect the vehicle exhaust gas located between the detection light emitting unit 110 and the first reflective device and / or between the first reflective device and the signal detection unit 130. In another embodiment, the reflective device 120 may also include a second reflective device, wherein the second reflective device is used to change the optical path of the detection light 170 passing through the first reflective device, so that the detection light 170 is received by the signal detection unit 130 after passing through the second reflective device, so as to detect the vehicle exhaust gas located between the first reflective device and the second reflective device and / or between the second reflective device and the signal detection unit 130.

[0036] from Figure 1 It can be observed that the detection light emitting unit 110 emits the detection light 170, which can be received by the signal detection unit 130 after being reflected by the reflection device 120. Furthermore, when the road target 150 travels along the front of the road, the exhaust gas 160 it emits can enter the area covered by the detection light 170. After passing through the exhaust gas 160 with different particulate matter concentrations, the detection light 170 will produce different degrees of absorption (that is, the opacity of the exhaust gas is different), and the light intensity of the detection light 170 reaching the signal detection unit 130 will also change accordingly. Therefore, the opacity of the exhaust puff can be determined based on the change in the light intensity of the signal detection unit 130, and then the concentration of particulate matter in the exhaust puff can be determined.

[0037] Furthermore, since the attenuation of the intensity of the detection light 170 follows a certain rule when passing through a medium with relatively uniform distribution and properties, the light intensity change trend received by the signal detection unit 130 is consistent with the frequency of the sinusoidal signal loaded by the detection light 170; and when there are other obstructions other than exhaust particles in the exhaust gas, the light intensity change of the detection light 170 will be out of sync with the periodic change of the sinusoidal signal loaded by the detection light 170, so that the light intensity change trend received by the signal detection unit 130 is inconsistent with the frequency of the sinusoidal signal loaded by the detection light 170.

[0038] In one embodiment, the detection light emitting unit 110 loads a sinusoidal signal with a frequency of 100 Hz to the detection light 170 in a variable power manner (i.e., a manner of changing the output of the light source). In this way, it is possible to effectively distinguish whether there are other obstructions other than exhaust particulate matter in the exhaust gas.

[0039] In another embodiment, when the frequency of the sinusoidal signal loaded by the detection light 170 is 100HZ, the signal detection unit 130 performs signal acquisition at a frequency of 100 sampling points in one cycle of the detection light 170, and the acquisition time is 10 cycles of the sinusoidal signal. In the above manner, when the speed of the vehicle passing through the exhaust gas detection system is 30km / h, the minimum diameter of the non-exhaust particle obstruction that the exhaust gas detection system can distinguish is 0.83mm, and the distance that the vehicle travels during the signal acquisition time is 8.3m, which can effectively exclude obstructions of non-exhaust particles such as thin wires and thin ropes and ensure that the signal of the detection light 170 passing through the exhaust gas can be collected. Among them, the minimum diameter of the non-exhaust particle obstruction is the length of the obstruction in the vertical direction between the obstruction and the detection light 170. It can be understood that in order to improve the efficiency of exhaust gas detection, it is expected that a large amount of data measured by the exhaust gas detection system can be processed. Therefore, the exhaust gas detection system may also include a data processing unit, which can be communicatively connected to the signal detection unit and can be used to: receive the electrical signal generated by the signal detection unit; generate a corresponding analog signal based on the electrical signal; and determine the opacity of the vehicle exhaust gas based on the analog signal.

[0040] In one embodiment, while detecting the opacity of the exhaust gas, it is desirable to simultaneously measure the diffusion velocity of the exhaust gas. Therefore, the cross-sectional area of ​​the detection light in any direction can be made larger than the cross-sectional area of ​​the exhaust gas, so that the detection light can completely cover the exhaust gas, and the diffusion velocity of the exhaust gas can be measured while enhancing the reliability of the measurement result.

[0041] In one implementation scenario, since different vehicles have different speeds when passing through the exhaust gas detection system, it is expected that the exhaust gas detection system can adaptively adjust the detection time according to different vehicle speeds to improve detection efficiency and reduce power consumption. Therefore, the exhaust gas detection system may also include a vehicle speed detection unit. The vehicle speed detection unit may be connected to the detection light emitting unit in communication and used to detect the speed of the vehicle to control the emission time of the detection light emitting unit to emit the detection light.

[0042] In another implementation scenario, it is expected that the detection result of the exhaust gas detection system can be bound to the detected vehicle to monitor and manage the pollution emission of the vehicle. Therefore, the exhaust gas detection system can also include a vehicle identification unit. The vehicle identification unit can be used to identify the vehicle to bind the detection result of the vehicle exhaust gas to the vehicle.

[0043] Figure 2 An exemplary flow chart of a vehicle exhaust gas detection method according to some embodiments of the present disclosure is shown.

[0044] As shown in the figure, in step S210, the first detection light data generated when the modulated light is continuously scanned during the period when the vehicle has not passed is obtained. There is no vehicle on the road during the period when the vehicle has not passed, that is, when the modulated light is continuously scanned. At this time, the first detection data obtained by the continuous scanning of the modulated light can be used to indicate the change in light intensity of the modulated light after passing through the air. Modulated light is to change certain characteristics of the light source through light source modulation technology. As mentioned above, the modulated light source described in the present disclosure can be a detection light output by the light source. Load a sinusoidal signal so that the energy intensity of the detection light changes periodically in a sinusoidal waveform. As mentioned above, when the detection light (i.e., modulated light) passes through a uniform and continuous medium (such as air or exhaust without obstructions other than exhaust particles), the frequency of the sinusoidal signal loaded by the detection light (i.e., modulated light) will not change. Therefore, the light intensity change of the modulated light indicated by the first detection light data is also a periodically changing sinusoidal signal.

[0045] Next, enter step S220 to obtain the second detection light data generated when the modulated light is continuously scanned during the vehicle passing period. During the vehicle passing period, that is, when the modulated light is continuously scanned, there are vehicles passing on the road. At this time, the second detection light data may include: when there are obstructions of non-exhaust particles in the exhaust gas, the data obtained by continuous scanning of the modulated light; when there are no obstructions of non-exhaust particles in the exhaust gas, the data obtained by continuous scanning of the modulated light. Therefore, the second detection light data can be used to indicate the change in light intensity of the modulated light after passing through the exhaust gas with obstructions of non-exhaust particles and the change in light intensity of the modulated light after passing through the exhaust gas without obstructions of non-exhaust particles. Further, when there are obstructions of non-exhaust particles in the exhaust gas, the frequency of light intensity change of the modulated light is inconsistent with the frequency of the sinusoidal signal loaded by the modulated light; when there are no obstructions of non-exhaust particles in the exhaust gas, the frequency of light intensity change of the modulated light is consistent with the frequency of the sinusoidal signal loaded by the modulated light.

[0046] Next, step S230 is entered, and valid data in the second detection light data is screened according to the correlation between the first detection light data and the second detection light data, wherein the valid data is the data when there is no obstruction in the exhaust gas. The data when there is no obstruction in the exhaust gas, that is, the data obtained by continuous scanning of the modulated light when there is no obstruction of non-exhaust particles in the exhaust gas, can be used to indicate the change of the intensity of the modulated light after the exhaust passes through the obstruction of non-exhaust particles. The correlation between the first detection light data and the second detection light data is the consistency between the frequency of the change of the intensity of the modulated light indicated by the first detection light data and the frequency of the change of the intensity of the modulated light indicated by the second detection light data. As mentioned above, when there is an obstruction of non-exhaust particles in the exhaust gas, the frequency of the change of the intensity of the modulated light is inconsistent with the frequency of the sinusoidal signal loaded by the modulated light; when there is no obstruction of non-exhaust particles in the exhaust gas, the frequency of the change of the intensity of the modulated light is consistent with the frequency of the sinusoidal signal loaded by the modulated light. Therefore, valid data can be screened according to the first detection light data and the second detection light data, that is, the data obtained by continuous scanning of the modulated light when there is no obstruction of non-exhaust particles in the exhaust gas is screened.

[0047] Finally, in step S240, the opacity of the exhaust gas is determined based on the first detection light data and the valid data. It can be understood that when there is no vehicle passing on the road, the data obtained by continuous scanning of the modulated light is the data of the modulated light passing through the air. At this time, it can be considered that the attenuation of the modulated light is caused by the absorption of the air; and when there is a vehicle passing on the road and there is no obstruction of non-exhaust particles in the exhaust gas, it can be considered that the attenuation of the modulated light is all caused by the absorption of the particles in the exhaust gas. According to the comparison of the modulated light passing through the air and the exhaust gas passing through the obstruction without non-exhaust particles, the degree of attenuation caused by the exhaust particles can be determined, thereby determining the opacity of the exhaust gas.

[0048] It can be understood that valid data can be used to indicate the change in the intensity of the modulated light after the exhaust passes through an obstruction where no non-exhaust particles exist, and since the second detection light data can include data when there is an obstruction of non-exhaust particles in the exhaust gas and data when there is no obstruction of non-exhaust particles in the exhaust gas. Among them, the data when there is an obstruction of non-exhaust particles in the exhaust gas will interfere with the data when there is no obstruction of non-exhaust particles in the exhaust gas, making the frequency of the change in the intensity of the modulated light indicated by the second detection light data inconsistent with the frequency of the sinusoidal signal loaded by the modulated light as a whole. Therefore, when screening valid data, the second detection light data needs to be segmented.

[0049] Specifically, filtering valid data in the second detection light data according to the first detection light data and the second detection light data includes: segmenting the second detection light data; and filtering valid data according to the first detection light data and the segmented second detection light data. In a preferred embodiment, the length of the segmentation of the second detection light data can be determined according to the length of the period of the sinusoidal signal loaded by the modulated light, so that the segmented second detection light data corresponds to a complete sinusoidal signal period. Furthermore, the starting point of the segmentation of the second light detection data is the dividing point between the first detection light data and the second detection light data. Furthermore, when a vehicle passes by, the modulated light will be blocked by the front of the vehicle, and the modulated light collection device (for example Figure 1 The light intensity signal collected by the signal detection unit in the first light detection data is 0, that is, when the collected light intensity signal drops to 0, it indicates that a vehicle has passed. Therefore, the time point (or sampling point) corresponding to the light intensity signal dropping to 0 can be used as the dividing point between the first light detection data and the second light detection data.

[0050] It can also be understood that the data obtained by continuously scanning the modulated light during the period when the vehicle has not passed can include multiple cycles of the sinusoidal signal loaded by the modulated light, and when filtering the valid data in the second detection light data according to the first detection light data and determining the opacity of the exhaust gas according to the first detection light data and the valid data, only one cycle of the first detection light data is needed. Therefore, in order to improve the calculation efficiency, the first detection light data corresponding to a certain time interval in the period when the vehicle has not passed can be intercepted. Specifically, the period when the vehicle has not passed can include a first time interval, wherein filtering the valid data in the second detection light data according to the first detection light data and the second detection light data includes: setting the first detection light data corresponding to the first time interval as a reference value; and filtering the valid data in the second detection light according to the reference value and the second detection light data.

[0051] Figure 3 A schematic diagram of a process for screening valid data in second detected light data according to some embodiments of the present disclosure is shown.

[0052] like Figure 3As shown, in step S310, the first detection light data and the segmented second detection light data are transformed in the time-frequency domain to obtain the first frequency domain data of the first detection light data and the second frequency domain data of the segmented second detection light data. As mentioned above, when the modulated light passes through the exhaust gas with obstructions other than exhaust particles, the frequency of its light intensity change is inconsistent with the frequency of the sinusoidal signal loaded by the modulated light; when the modulated light passes through the exhaust gas with no obstructions other than exhaust particles, the frequency of its light intensity change is consistent with the frequency of the sinusoidal signal loaded by the modulated light, that is, the particulate matter in the exhaust gas and the non-particulate obstructions can be distinguished by the difference in the frequency of the modulated light intensity change. Furthermore, the difference in frequency can be more intuitively observed based on the frequency domain data of the first detection light data and the second detection light data; at the same time, it is also easier for the computer to identify the particulate matter and non-particulate obstructions in the exhaust gas through the algorithm model.

[0053] In one embodiment, for example, the first detection light data and the second detection light data may be transformed in time-frequency domain by FFT (fast fourier transform) to obtain first frequency domain data of the first detection light data and second frequency domain data of the divided second detection light data.

[0054] Next, in step S320, valid data is screened according to the first frequency domain data and the second frequency domain data.

[0055] In one embodiment, the first detected light data and the second detected light data may be acquired by a modulated light acquisition device (eg Figure 1 The first detected light data and the second detected light data are obtained by sampling at a certain sampling frequency by the signal detection unit in the optical fiber signal detection unit, that is, the first detected light data and the second detected light data are discrete. Therefore, the first frequency domain data and the second frequency domain data obtained according to the first detected light data and the second detected light data may also be discrete. Further, in order to better observe the data and remove unreliable data, curve fitting may be performed on the discrete data. Specifically, screening the valid data according to the first frequency domain data and the second frequency domain data includes: performing curve fitting on the first frequency domain data and the second frequency domain data to obtain a first curve of the first frequency domain data and a second curve of the second frequency domain data; and screening the valid data according to the correlation coefficient of the first curve and the second curve.

[0056] It can be understood that the correlation coefficient between the curves can be used to indicate the difference in distribution shape between two variables. As mentioned above, the frequency of change of the modulated light intensity indicated by the first detection light data is consistent with the frequency of the sinusoidal signal loaded by the modulated light, that is, the frequency component indicated by the curve fitted by the first frequency domain data obtained according to the first detection light data is relatively simple; while the frequency of change of the modulated light intensity indicated by the second detection light data when the exhaust gas passes through the obstruction where non-exhaust particulate matter exists is inconsistent with the frequency of the sinusoidal signal loaded by the modulated light, and the frequency component indicated by the fitted curve is relatively complex. Therefore, valid data in the second detection light data can be screened according to the correlation coefficient of the first curve and the second curve. Specifically, screening valid data according to the correlation coefficient of the first curve and the second curve includes: when the correlation coefficient of the first curve and the second curve is greater than a preset threshold, the second detection light data corresponding to the second curve is determined as valid data.

[0057] In one embodiment, the correlation coefficient between the first curve and the second curve may be determined according to the following formula (1):

[0058]

[0059] Wherein, R is the correlation coefficient between the first curve and the second curve, i is any value greater than 1, xi is the value of the first curve when the horizontal coordinate is i, yi is the value of the second curve when the horizontal coordinate is i, is the average value of the first curve, By calculating the correlation coefficient between the first curve and the second curve, when the correlation coefficient between the second curve and the first curve is greater than a given threshold, it is considered that the frequency component indicated by the second curve is relatively single, that is, the corresponding second detection light data is valid data.

[0060] Figure 4 An exemplary flow chart of a method for determining the opacity of exhaust gas according to some embodiments of the present disclosure is shown.

[0061] like Figure 4 As shown, in step S410, the first detection light data and the effective data are transformed in the time-frequency domain to obtain first time-domain data of the first detection light data and second time-domain data of the effective data. The first time-domain data can be used to indicate the change of the light intensity of the modulated light over time after passing through the air; the second time-domain data can be used to indicate the change of the light intensity of the modulated light over time after passing through the exhaust without an obstruction of non-exhaust particles.

[0062] Next, enter step S420, and determine the opacity of the exhaust gas based on the first time domain data and the second time domain data. As mentioned above, when there is no vehicle passing on the road, the data obtained by continuous scanning of the modulated light is the data of the modulated light passing through the air, and the attenuation of the modulated light is caused by the absorption of the air; when there is a vehicle passing on the road and there are no obstructions other than the exhaust gas particles in the exhaust gas, the attenuation of the modulated light is all caused by the absorption of the particles in the exhaust gas. Therefore, the opacity of the exhaust gas can be determined by comparing the degree of attenuation of the light intensity of the modulated light after the exhaust gas passes through the obstruction without the non-exhaust gas particles relative to the exhaust gas passing through the air.

[0063] It is understandable that during the period when the vehicle passes, the exhaust gas emitted by the vehicle will diffuse over time, and the concentration of particulate matter will also be different, that is, the valid data may include data collected in multiple time periods that pass through different particle concentrations. Therefore, a set of valid data indicating the maximum attenuation of the average light intensity of the modulated light after the exhaust passes through an obstruction where there are no non-exhaust particles can be used as data for evaluating the opacity of the exhaust gas. It is also understandable that the energy intensity of the modulated light changes periodically, and the greater the energy intensity, the higher the reliability of the measured data. Therefore, the peak value of the light intensity change in a set of valid data can be used as a value for evaluating the opacity of the exhaust gas.

[0064] As mentioned above, the cross-sectional area of ​​the detection light (modulated light) in any direction can be larger than the cross-sectional area of ​​the exhaust gas. Therefore, the exhaust gas can diffuse within the range covered by the detection light, that is, the speed of exhaust gas diffusion can be calculated based on the data collected by the signal acquisition device. Specifically, the second detection light data also includes exhaust gas diffusion data, and the vehicle exhaust detection method can also include: detecting the diffusion speed of the vehicle exhaust gas based on the exhaust gas diffusion data.

[0065] In some possible implementations, various aspects of the present disclosure may also be implemented as an electronic device 500 . Figure 5 A schematic block diagram of an electronic device according to some embodiments of the present disclosure is shown.

[0066] like Figure 5 As shown, the electronic device 500 includes a processor 510 and a memory 520. When the processor 510 executes the program data stored in the memory 520, the above combination is realized. Figure 1-Figure 4 The method and steps of its various embodiments are described.

[0067] In some other possible implementations, various aspects of the present disclosure may also be implemented as a computer-readable storage medium having computer program instructions stored thereon, the instructions being executed by one or more processors to implement the above-mentioned Figure 1-Figure 4The described method and steps of multiple embodiments thereof. The computer readable storage medium may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0068] Although multiple embodiments of the present disclosure have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art may think of many changes, modifications, and alternatives without departing from the thought and spirit of the present disclosure. It should be understood that in the process of practicing the present disclosure, various alternatives to the embodiments of the present disclosure described herein may be adopted. The attached claims are intended to define the scope of protection of the present disclosure, and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A system for detecting vehicle exhaust, characterized in that: include: A detection light emitting unit, which is used to emit detection light, wherein the detection light is modulated light loaded with a sinusoidal signal; a signal detection unit, which is communicatively connected to the detection light emitting unit, and is used to receive the detection light and generate a corresponding electrical signal according to the detection light; and A data processing unit is communicatively connected with the signal detection unit and is used for: receiving the electrical signal; generating a corresponding analog signal according to the electrical signal; and The opacity of the vehicle exhaust is determined based on the analog signal.

2. The system according to claim 1, characterized in that It also includes a reflecting device, wherein the reflecting device is used to change the optical path of the detection light to detect the vehicle exhaust located at different positions.

3. The system according to claim 2, characterized in that The reflecting device includes a first reflecting device, wherein the first reflecting device is used to change the optical path of the detection light so that the detection light is received by the signal detection unit after passing through the first reflecting device, so as to detect the vehicle exhaust gas located between the detection light emitting unit and the first reflecting device and / or between the first reflecting device and the signal detection unit.

4. The system according to claim 3, characterized in that The reflecting device also includes a second reflecting device, wherein the second reflecting device is used to change the optical path of the detection light passing through the first reflecting device, so that the detection light is received by the signal detection unit after passing through the second reflecting device, so as to detect the vehicle exhaust located between the first reflecting device and the second reflecting device and / or between the second reflecting device and the signal detection unit.

5. The system according to claim 1, characterized in that The detection light emitting unit applies a sinusoidal signal to the detection light in a variable power manner.

6. The system according to claim 1, characterized in that The cross-sectional area of ​​the detection light in any direction is larger than the cross-sectional area of ​​the exhaust gas.

7. The system according to claim 2, characterized in that The reflecting device comprises a reflecting mirror and an adjusting frame, wherein the reflecting mirror is arranged on the adjusting frame so that the height and / or angle of the reflecting mirror can be adjusted through the adjusting frame.

8. The system according to claim 1, characterized in that It also includes a vehicle speed detection unit, wherein the vehicle speed detection unit is communicatively connected with the detection light emitting unit and is used to detect the speed of the vehicle so as to control the emission time of the detection light emitted by the detection light emitting unit.

9. The system according to any one of claims 1 to 8, characterized in that: It also includes a vehicle identification unit, wherein the vehicle identification unit is used to identify the vehicle so as to bind the detection result of the vehicle exhaust gas to the vehicle.

Images