Obstacle height recognition method and system based on ultrasonic detection

Abstract

The embodiment of the application discloses a kind of obstacle height identification method and system based on ultrasonic detection, it is related to low-speed scene obstacle identification technical field.The method comprises: obtaining ultrasonic radar installation height, real-time collection environment temperature and humidity and correct sound speed;Emit ultrasonic wave and collect echo signal, filter calculation and determine effective main reflection signal and effective secondary reflection signal, respectively record the propagation time of both;Calculate main, secondary reflection distance;Combined with ultrasonic radar installation height, calculate obstacle height based on geometric relationship model;Obtain vehicle body pitch angle and carry out attitude correction, obtain final height;Compare with preset height threshold, output the height classification of obstacle.The application realizes the accurate identification of obstacle height without increasing hardware cost, especially suitable for automatic parking, narrow road meeting and other low-speed scenes, effectively improves the safety of obstacle avoidance and user experience.

Description

Technical Field

[0001] This invention relates to the field of obstacle recognition technology in low-speed motor vehicle scenarios, and in particular to a method and system for obstacle height recognition based on ultrasonic detection. Background Technology

[0002] In low-speed driving scenarios such as low-speed automatic parking and passing on narrow roads, the height of obstacles is a key parameter for determining whether it is safe to pass or avoid them. Among current mainstream solutions, ultrasonic radar is widely deployed around vehicles due to its low cost and high accuracy at short range.

[0003] However, traditional ultrasonic radar primarily relies on echo time to calculate straight-line distance, lacking the ability to effectively analyze obstacle height information. It cannot distinguish between low obstacles such as curbs, parking locks, and speed bumps, and taller obstacles such as walls and vehicles. This leads to problems such as tire scraping, chassis damage, and doors failing to open properly after parking due to misjudgment of obstacle height during parking or passing, seriously affecting driving safety and user experience.

[0004] Existing improvement solutions mostly rely on multi-sensor fusion (such as cameras and LiDAR) or complex modeling, but these suffer from drawbacks such as high cost, high computing power requirements, and poor real-time performance. Therefore, how to improve the ability to identify obstacle heights while maintaining the low-cost advantage of ultrasonic radar is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The technical problem to be solved by the embodiments of the present invention is to provide an obstacle height recognition method and system based on ultrasonic detection, which can significantly improve the recognition accuracy and scene adaptability of ultrasonic radar for obstacle height, and effectively improve obstacle avoidance safety and user experience.

[0006] To address the aforementioned technical problems, as one aspect of the present invention, a method for obstacle height recognition based on ultrasonic detection is provided, comprising the following steps: Step S1: Obtain the installation height of the ultrasonic radar on the vehicle, and collect the ambient temperature and humidity in real time, and correct the ultrasonic propagation speed according to the ambient temperature and humidity. Step S2: Emit ultrasonic waves and collect echo signals. Filter, calculate, and determine the effective primary reflection signal and the effective secondary reflection signal from the echo signals, and record the propagation time of each. Step S3: Calculate the primary reflection distance and secondary reflection distance based on the propagation time of the two and the corrected ultrasonic propagation speed; Step S4: Calculate the estimated height of the obstacle based on the installation height, primary reflection distance, and secondary reflection distance of the ultrasonic radar, using a preset geometric relationship model. Step S5: Obtain the real-time pitch angle of the vehicle body, and use the pitch angle to correct the attitude of the calculated height to obtain the final height of the obstacle; Step S6: Compare the final height with the preset height and low obstacle threshold to determine the height and low classification attributes of the obstacle.

[0007] Preferably, step S2 further includes: Time-domain filtering is performed: the actual time-domain values ​​of the primary reflection signal and the secondary reflection signal are calculated respectively, and the time difference Δt = |T – t| between the actual time-domain value and the effective time-domain value of the same type of reflection signal preset by the system is further calculated, where T represents the actual time-domain value of the primary reflection signal or the secondary reflection signal obtained by calculation, and t represents the effective time-domain value of the primary reflection signal or the secondary reflection signal preset by the system. When the time difference Δt is greater than the preset time-domain difference threshold, the corresponding reflection signal is judged as noise and removed. Amplitude filtering is performed: the actual amplitudes of the primary and secondary reflected signals are calculated respectively, and the amplitude ratio K = A / a of the actual amplitudes and the effective amplitudes of the same type of reflected signals preset by the system is further calculated. Where A represents the actual amplitude of the primary or secondary reflected signal, and a represents the effective amplitude of the primary or secondary reflected signal preset by the system. When the amplitude ratio K is less than the preset amplitude threshold, the corresponding reflected signal is judged as noise and discarded.

[0008] Preferably, in step S4, the step of calculating the estimated height of the obstacle based on a preset geometric relationship model includes: When the height of the obstacle is determined to be higher than the installation height of the ultrasonic radar, according to the formula... and Derivation: And according to the formula Calculate the height of obstacles ; When the height of the obstacle is determined to be lower than the installation height of the ultrasonic radar, according to the formula... and Derivation: And according to the formula Calculate the height of obstacles ; Where d1 and d2 are the primary reflection distance and secondary reflection distance corresponding to the primary reflection signal and the secondary reflection signal, respectively, D is the horizontal distance between the obstacle and the vehicle, Δh is the absolute value of the difference between the obstacle height and the ultrasonic radar installation height, and h0 is the ultrasonic radar installation height.

[0009] Preferably, in step S1, the ultrasonic wave propagation speed V is corrected using the following formula: Where T is the ambient temperature and H is the ambient humidity; In step S5, the height information is corrected for attitude using the following formula to obtain the true height of the obstacle Hobj: Hobj = ΔHobj × cosα, where α is the real-time pitch angle of the vehicle body.

[0010] Preferably, step S6 further includes: Multiple height threshold ranges are preset, and the final height Hobj is compared with the height threshold ranges to output the height attribute classification of the obstacle. The height threshold range includes: low obstacle range (Hobj < 0.5m), medium obstacle range (0.5m ≤ Hobj < 1.2m), and large obstacle range (Hobj ≥ 1.2m).

[0011] On the other hand, embodiments of the present invention also provide an obstacle height recognition system based on ultrasonic detection, comprising: An environmental correction module is used to obtain the installation height of the vehicle's ultrasonic radar and collect ambient temperature and humidity in real time, and correct the ultrasonic propagation speed based on the ambient temperature and humidity. The signal processing module is used to emit ultrasonic waves and collect echo signals, filter, calculate and determine the effective primary reflection signal and the effective secondary reflection signal from the echo signals, and record the propagation time of each; The distance calculation module is used to calculate the primary reflection distance and the secondary reflection distance based on the propagation time of the two and the corrected ultrasonic propagation speed. The height estimation module is used to calculate the estimated height of the obstacle based on a preset geometric relationship model, according to the installation height of the ultrasonic radar, the primary reflection distance, and the secondary reflection distance. The attitude correction module is used to obtain the real-time pitch angle of the vehicle body, and use the pitch angle to correct the attitude of the calculated height to obtain the final height of the obstacle. The classification decision module is used to compare the final height with a preset height and low obstacle threshold to determine the height and low classification attributes of the obstacle.

[0012] Preferably, the signal processing module includes: The time-domain filtering unit is used to calculate the actual time-domain values ​​of the primary reflection signal and the secondary reflection signal respectively, and further calculate the time difference Δt = |T – t| between the actual time-domain values ​​and the effective time-domain values ​​of the same type of reflection signal preset by the system. Where T represents the actual time-domain value of the primary reflection signal or the secondary reflection signal obtained by calculation, and t represents the effective time-domain value of the primary reflection signal or the secondary reflection signal preset by the system. When the time difference Δt is greater than the preset time-domain difference threshold, the corresponding reflection signal is judged as noise and discarded. An amplitude filtering unit is used to calculate the actual amplitude of the primary reflection signal and the secondary reflection signal respectively, and further calculate the amplitude ratio K = A / a between the actual amplitude and the effective amplitude of the same type of reflection signal preset by the system. Here, A represents the actual amplitude of the primary reflection signal or the secondary reflection signal, and a represents the effective amplitude of the primary reflection signal or the secondary reflection signal preset by the system. When the amplitude ratio K is less than the preset amplitude threshold, the corresponding reflection signal is judged as noise and discarded.

[0013] Preferably, the height calculation module includes: The high obstacle calculation unit is used to calculate the obstacle height when it is determined that the obstacle height is higher than the installation height of the ultrasonic radar, based on the formula. and Derivation: And according to the formula Calculate the height of obstacles ; The low obstacle calculation unit is used to calculate the obstacle height when it is determined to be lower than the installation height of the ultrasonic radar, based on the formula... and Derivation: And according to the formula Calculate the height of obstacles ; Where d1 and d2 are the primary reflection distance and secondary reflection distance corresponding to the primary reflection signal and the secondary reflection signal, respectively, D is the horizontal distance between the obstacle and the vehicle, Δh is the absolute value of the difference between the obstacle height and the ultrasonic radar installation height, and h0 is the ultrasonic radar installation height.

[0014] Preferably, in the environmental correction module, the formula for correcting the ultrasonic wave propagation speed V according to the following formula is: Where T is the ambient temperature and H is the ambient humidity; In the attitude correction module, the height information is corrected using the following formula to obtain the true height of the obstacle, Hobj: Hobj = ΔHobj × cosα, where α is the real-time pitch angle of the vehicle body.

[0015] Preferably, the classification decision module is specifically used to: preset multiple height threshold intervals, compare the final height Hobj with the height threshold intervals, and output the height attribute classification of the obstacle; the height threshold intervals include: low obstacle interval (Hobj<0.5m), medium obstacle interval (0.5m ≤ Hobj<1.2m), and large obstacle interval (Hobj ≥ 1.2m).

[0016] Implementing the embodiments of this invention has the following beneficial effects: This invention provides an obstacle height recognition method and system based on ultrasonic detection. By extracting primary and secondary reflection signals and combining them with temperature and humidity corrections for sound speed, it overcomes the shortcomings of traditional ultrasonic sensors in obtaining height information, achieving millimeter-level height estimation and improving the recognition accuracy to over 90%. In this embodiment, by introducing the real-time vehicle pitch angle for attitude correction of the estimated height, it effectively addresses height measurement deviations on uneven road conditions such as uphill and downhill slopes, making it suitable for complex low-speed driving environments. In this embodiment, by setting multi-level height threshold ranges, it can clearly distinguish between low, medium, and large obstacles, providing a more reasonable obstacle avoidance strategy for parking systems and preventing restricted door opening or chassis scratches. In this embodiment, no additional sensors or high-computing platforms are required; height recognition can be achieved solely using existing ultrasonic radar and its echo signal characteristics, demonstrating significant engineering application value. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the main flow of an embodiment of an obstacle height recognition method based on ultrasonic detection provided by the present invention.

[0019] Figure 2 for Figure 1 The provided method includes a schematic diagram illustrating the principle of calculating the estimated height of an obstacle when its height is higher than the installation height of the ultrasonic radar.

[0020] Figure 3 for Figure 1 The provided method includes a schematic diagram illustrating the principle of calculating the estimated height of an obstacle when its height is lower than the installation height of the ultrasonic radar.

[0021] Figure 4 for Figure 1 The provided method uses a schematic diagram to illustrate the principle of attitude correction based on altitude information.

[0022] Figure 5 This is a schematic diagram of an embodiment of an obstacle height recognition system based on ultrasonic detection provided by the present invention.

[0023] Figure 6 for Figure 5 A schematic diagram of the signal processing module in the image.

[0024] Figure 7 for Figure 5 A schematic diagram of the height calculation module in the image. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the following illustrative embodiments and descriptions are only used to explain the technical principles and feasible solutions of the present invention, and are not intended to limit the present invention. Moreover, in the absence of conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0026] like Figure 1 The diagram shown illustrates the main flow of an embodiment of an obstacle height recognition method based on ultrasonic detection provided by the present invention; in conjunction with... Figures 2 to 4 As shown, in this embodiment, the obstacle height recognition method based on ultrasonic detection includes the following steps: Step S1: Obtain the installation height of the ultrasonic radar on the vehicle, and collect the ambient temperature and humidity in real time, and correct the ultrasonic propagation speed according to the ambient temperature and humidity. Step S2: Emit ultrasonic waves and collect echo signals. Filter, calculate, and determine the effective primary reflection signal and the effective secondary reflection signal from the echo signals, and record the propagation time of each. Step S3: Calculate the primary reflection distance and secondary reflection distance based on the propagation time of the two and the corrected ultrasonic propagation speed; Step S4: Calculate the estimated height of the obstacle based on the installation height, primary reflection distance, and secondary reflection distance of the ultrasonic radar, using a preset geometric relationship model. Step S5: Obtain the real-time pitch angle of the vehicle body, and use the pitch angle to correct the attitude of the calculated height to obtain the final height of the obstacle; Step S6: Compare the final height with the preset height and low obstacle threshold to determine the height and low classification attributes of the obstacle.

[0027] The following will be combined Figures 2 to 4 Each step of this method is explained in detail.

[0028] Understandably, higher temperatures and lower humidity generally result in greater air resistance to ultrasound, necessitating adjustments to the ultrasound propagation speed in the air based on temperature and humidity. Therefore, in this specific example, in step S1, the ultrasound propagation speed V is corrected using the following formula: Where T is the ambient temperature and H is the ambient humidity. In this step, the installation height h0 of the ultrasonic radar also needs to be measured.

[0029] In specific examples, it is necessary to collect and analyze the primary and secondary reflection signals and remove clutter and invalid signals. In these examples, real obstacles are usually irregular, and the emitted ultrasonic waves will be reflected by the surface of the obstacle to form a kind of diffuse reflection. Some of the waves are reflected directly back, while others are reflected back secondary or multiple times by other obstacles or low obstacles.

[0030] Therefore, in a specific example, step S2 further includes: Time-domain filtering is performed: the actual time-domain values ​​of the primary reflection signal and the secondary reflection signal are calculated respectively, and the time difference Δt = |T – t| between the actual time-domain value and the effective time-domain value of the same type of reflection signal preset by the system is further calculated, where T represents the actual time-domain value of the primary reflection signal or the secondary reflection signal obtained by calculation, and t represents the effective time-domain value of the primary reflection signal or the secondary reflection signal preset by the system. When the time difference Δt is greater than the preset time-domain difference threshold (time_delta_threshold), the corresponding reflection signal is judged as noise and discarded. Amplitude filtering is performed: the actual amplitudes of the primary and secondary reflected signals are calculated respectively, and the amplitude ratio K = A / a of the actual amplitudes and the effective amplitudes of the same type of reflected signals preset by the system is further calculated, where A represents the actual amplitude of the primary or secondary reflected signal, and a represents the effective amplitude of the primary or secondary reflected signal preset by the system. When the amplitude ratio K is less than the preset amplitude threshold, the corresponding reflected signal is judged as noise and discarded.

[0031] In this step, the actual time-domain value and actual amplitude of each reflected signal are calculated and compared with the effective time-domain value and effective amplitude of the same type of reflected signal preset in the system. Specifically, the actual time-domain value and actual amplitude of the main reflected signal are compared with the preset effective time-domain value and effective amplitude of the main reflected signal, and the actual time-domain value and actual amplitude of the secondary reflected signal are compared with the preset effective time-domain value and effective amplitude of the secondary reflected signal. When the relevant conditions are met, the reflected signal is treated as noise and eliminated, which can effectively remove invalid echoes. It can be understood that the amplitude comparison processing is equivalent to filtering out a portion of invalid waves through the echo reflection height. The echo height of different obstacles such as walls, pillars, curbs, speed bumps, etc., is within a certain range. If it exceeds the range, it is considered an invalid wave.

[0032] In step S3, the primary reflection distance and secondary reflection distance are calculated in the following manner: Based on the propagation time t1 of the primary reflected signal, the primary reflection distance d1 = V × t1 / 2 is calculated. The secondary reflection distance d2 is calculated as V×t2 / 2 based on the propagation time t2 of the secondary reflection signal. like Figure 2 and Figure 3 As shown, the primary reflection distance corresponding to the primary reflection signal is d1, and the secondary reflection distance corresponding to the secondary reflection signal is d2 (the two solid line segments with arrows located below d1).

[0033] In step S4, the step of calculating the estimated height of the obstacle based on a preset geometric relationship model includes: When the height of the obstacle is determined to be higher than the installation height of the ultrasonic radar, according to the formula... and Derivation: And according to the formula Calculate the height of obstacles The specific schematic diagram is as follows: Figure 2 As shown. It's understandable that in practical applications, it's assumed the ultrasonic reflected wave won't be reflected precisely from the highest point of the obstacle. Ultrasonic waves have installation height and emission angle; generally, obstacles exceeding 1 meter in vertical height become undetectable. d1 is used to illustrate that if the distance of the received reflected wave is greater than D (combined with the filtered effective wave), it indicates the obstacle's height is greater than the ultrasonic radar's installation height. Within the range where the reflected wave can be received, the approximate height of the obstacle's reflection cutoff point is calculated. Using d2, a right triangle is formed by mirroring and extending it. In this right triangle, the hypotenuse is d2, the base leg is D, and the vertical leg is 2Δh + 2h0. Based on this information, the previous formulas can be derived, thus calculating the estimated obstacle height. .

[0034] When the height of the obstacle is determined to be lower than the installation height of the ultrasonic radar, according to the formula... and Derivation: And according to the formula Calculate the height of obstacles The specific schematic diagram is as follows: Figure 3 As shown, its principle is the same as Figure 2 Similarly, except that after the mirror image forms a right triangle, its hypotenuse is d2, its base is D, and its vertical side is 2h0-2△h.

[0035] Where D is the horizontal distance between the obstacle and the vehicle, and △h is the absolute value (positive value) of the difference between the obstacle height and the ultrasonic radar installation height.

[0036] In step S5, the real-time pitch angle α of the vehicle body is obtained through the vehicle body IMU or ESP, and the attitude of the calculated △Hobj is corrected accordingly. Figure 4(The height is marked with △h). Specifically, the height information is corrected for attitude using the following formula to obtain the true height of the obstacle, Hobj: Hobj = ΔHobj × cosα, where α is the real-time pitch angle of the vehicle body.

[0037] Step S6 further includes: Multiple height threshold ranges are preset, and the final height Hobj is compared with the height threshold ranges to output the height attribute classification of the obstacle. The height threshold range includes: Low-profile obstacle zones (Hobj < 0.5m), such as curbs and ground locks; Medium-sized obstacle courses (0.5m ≤ Hobj < 1.2m), such as guardrails, water-filled barriers, etc. And large obstacle zones (Hobj ≥ 1.2m), such as pedestrians, electric vehicles, etc.

[0038] It is understood that the method provided by this invention can achieve accurate measurement of obstacle height without significantly increasing hardware costs. This improves the ability to accurately identify the height of obstacles, especially during low-speed APA parking, and allows for reasonable control of the distance to obstacles behind the vehicle, facilitating the opening of doors for getting in and out of the car.

[0039] like Figure 5 The diagram shows a structural schematic of an embodiment of an obstacle height recognition system based on ultrasonic detection provided by the present invention, in conjunction with... Figure 6 and Figure 7 As shown, in this embodiment, the obstacle height recognition system 1 based on ultrasonic detection includes at least: The environmental correction module 10 is used to obtain the installation height of the ultrasonic radar of the vehicle, and to collect the ambient temperature and humidity in real time, and correct the ultrasonic propagation speed according to the ambient temperature and humidity. Signal processing module 11 is used to emit ultrasonic waves and collect echo signals, filter, calculate and determine the effective primary reflection signal and the effective secondary reflection signal from the echo signals, and record the propagation time of each; The distance calculation module 12 is used to calculate the primary reflection distance and the secondary reflection distance based on the propagation time of the two and the corrected ultrasonic propagation speed. The height estimation module 13 is used to calculate the estimated height of the obstacle based on a preset geometric relationship model, according to the installation height of the ultrasonic radar, the primary reflection distance, and the secondary reflection distance. The attitude correction module 14 is used to obtain the real-time pitch angle of the vehicle body, and use the pitch angle to correct the attitude of the calculated height to obtain the final height of the obstacle. The classification decision module 15 is used to compare the final height with a preset high and low obstacle threshold to determine the high and low classification attributes of the obstacle.

[0040] Specifically, in the environmental correction module 10, the formula for correcting the ultrasonic wave propagation speed V according to the following formula is: Where T is the ambient temperature and H is the ambient humidity.

[0041] like Figure 6 As shown, in a specific example, the signal processing module 11 further includes: The time-domain filtering unit 110 is used to calculate the actual time-domain values ​​of the primary reflection signal and the secondary reflection signal respectively, and further calculate the time difference Δt = |T – t| between the actual time-domain values ​​and the effective time-domain values ​​of the same type of reflection signal preset by the system. Where T represents the actual time-domain value of the primary reflection signal or the secondary reflection signal obtained by calculation, and t represents the effective time-domain value of the primary reflection signal or the secondary reflection signal preset by the system. When the time difference Δt is greater than the preset time-domain difference threshold, the corresponding reflection signal is determined to be noise and removed. The amplitude filtering unit 111 is used to calculate the actual amplitude of the primary reflection signal and the secondary reflection signal respectively, and further calculate the amplitude ratio K = A / a between the actual amplitude and the effective amplitude of the same type of reflection signal preset by the system, where A represents the actual amplitude of the primary reflection signal or the secondary reflection signal, and a represents the effective amplitude of the primary reflection signal or the secondary reflection signal preset by the system. When the amplitude ratio K is less than the preset amplitude threshold, the corresponding reflection signal is judged as noise and discarded.

[0042] Specifically, in the distance calculation module 12, the primary reflection distance and secondary reflection distance are calculated in the following manner: Based on the propagation time t1 of the primary reflected signal, the primary reflection distance d1 = V × t1 / 2 is calculated. The secondary reflection distance d2 is calculated as V×t2 / 2 based on the propagation time t2 of the secondary reflection signal.

[0043] like Figure 7 As shown, in a specific example, the height calculation module 13 includes: The high obstacle calculation unit 130 is used to calculate the obstacle height according to the formula when the obstacle height is determined to be higher than the installation height of the ultrasonic radar. and Derivation: And according to the formula Calculate the height of obstacles ; The low obstacle calculation unit 131 is used to calculate the obstacle height according to the formula when the obstacle height is determined to be lower than the installation height of the ultrasonic radar. and Derivation: And according to the formula Calculate the height of obstacles ; Where d1 and d2 are the primary reflection distance and secondary reflection distance corresponding to the primary reflection signal and the secondary reflection signal, respectively, D is the horizontal distance between the obstacle and the vehicle, Δh is the absolute value of the difference between the obstacle height and the ultrasonic radar installation height, and h0 is the ultrasonic radar installation height.

[0044] More specifically, in the attitude correction module 14, the height information is corrected using the following formula to obtain the true height of the obstacle Hobj: Hobj = ΔHobj × cosα, where α is the real-time pitch angle of the vehicle body; More specifically, the classification decision module 15 classifies obstacle heights in the following manner: Multiple height threshold ranges are preset, and the final height Hobj is compared with the height threshold ranges to output the height attribute classification of the obstacle; the height threshold ranges include: low obstacle range (Hobj<0.5m), medium obstacle range (0.5m ≤ Hobj<1.2m), and large obstacle range (Hobj ≥ 1.2m).

[0045] Implementing this embodiment has the following beneficial effects: This invention provides an obstacle height identification method and system based on ultrasonic detection. By extracting primary and secondary reflection signals and combining them with temperature and humidity corrections for sound velocity, it overcomes the shortcomings of traditional ultrasonic waves in obtaining height information, achieves millimeter-level height estimation, and improves the identification accuracy to over 90%. In this embodiment of the invention, the calculated height is corrected by introducing the real-time pitch angle of the vehicle body, which effectively addresses the height measurement deviation under uneven road conditions such as uphill and downhill slopes, and is suitable for complex low-speed driving environments. In this embodiment of the invention, by setting multiple height threshold ranges, low, medium and large obstacles can be clearly distinguished, providing a more reasonable obstacle avoidance strategy for the parking system and avoiding restricted door opening or chassis scratches. In this embodiment of the invention, no additional sensors or high-performance computing platforms are required. High-resolution identification can be achieved simply by utilizing existing ultrasonic radar and its echo signal characteristics, which has good engineering application value.

[0046] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, apparatus, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0047] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0048] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many variations under the guidance of the present invention without departing from the inventive spirit and scope of protection of the claims. These variations are all within the scope of protection of the present invention.

Claims

1. A method for obstacle height recognition based on ultrasonic detection, characterized in that, Includes the following steps: Step S1: Obtain the installation height of the ultrasonic radar on the vehicle, and collect the ambient temperature and humidity in real time, and correct the ultrasonic propagation speed according to the ambient temperature and humidity. Step S2: Emit ultrasonic waves and collect echo signals. Filter, calculate, and determine the effective primary reflection signal and the effective secondary reflection signal from the echo signals, and record the propagation time of each. Step S3: Calculate the primary reflection distance and secondary reflection distance based on the propagation time of the two and the corrected ultrasonic propagation speed; Step S4: Calculate the estimated height of the obstacle based on the installation height, primary reflection distance, and secondary reflection distance of the ultrasonic radar, using a preset geometric relationship model. Step S5: Obtain the real-time pitch angle of the vehicle body, and use the pitch angle to correct the attitude of the calculated height to obtain the final height of the obstacle; Step S6: Compare the final height with the preset height and low obstacle threshold to determine the height and low classification attributes of the obstacle.

2. The method according to claim 1, characterized in that, Step S2 further includes: Time-domain filtering is performed: the actual time-domain values ​​of the primary reflection signal and the secondary reflection signal are calculated respectively, and the time difference Δt = |T – t| between the actual time-domain value and the effective time-domain value of the same type of reflection signal preset by the system is further calculated, where T represents the actual time-domain value of the primary reflection signal or the secondary reflection signal obtained by calculation, and t represents the effective time-domain value of the primary reflection signal or the secondary reflection signal preset by the system. When the time difference Δt is greater than the preset time-domain difference threshold, the corresponding reflection signal is judged as noise and removed. Amplitude filtering is performed: the actual amplitudes of the primary and secondary reflected signals are calculated respectively, and the amplitude ratio K = A / a of the actual amplitudes and the effective amplitudes of the same type of reflected signals preset by the system is further calculated. Where A represents the actual amplitude of the primary or secondary reflected signal, and a represents the effective amplitude of the primary or secondary reflected signal preset by the system. When the amplitude ratio K is less than the preset amplitude threshold, the corresponding reflected signal is judged as noise and discarded.

3. The method according to claim 2, characterized in that, In step S4, the step of calculating the estimated height of the obstacle based on a preset geometric relationship model includes: When the height of the obstacle is determined to be higher than the installation height of the ultrasonic radar, according to the formula... and Derivation: And according to the formula Calculate the height of obstacles ; When the height of the obstacle is determined to be lower than the installation height of the ultrasonic radar, according to the formula... and Derivation: And according to the formula Calculate the height of obstacles ; Where d1 and d2 are the primary reflection distance and secondary reflection distance corresponding to the primary reflection signal and the secondary reflection signal, respectively, D is the horizontal distance between the obstacle and the vehicle, Δh is the absolute value of the difference between the obstacle height and the ultrasonic radar installation height, and h0 is the ultrasonic radar installation height.

4. The method according to claim 3, characterized in that, in: In step S1, the ultrasonic wave propagation speed V is corrected using the following formula: Where T is the ambient temperature and H is the ambient humidity; In step S5, the height information is corrected for attitude using the following formula to obtain the true height of the obstacle Hobj: Hobj = ΔHobj × cosα, where α is the real-time pitch angle of the vehicle body.

5. The method according to claim 4, characterized in that, Step S6 further includes: Multiple height threshold ranges are preset, and the final height Hobj is compared with the height threshold ranges to output the height attribute classification of the obstacle. The height threshold range includes: low obstacle range (Hobj < 0.5m), medium obstacle range (0.5m ≤ Hobj < 1.2m), and large obstacle range (Hobj ≥ 1.2m).

6. An obstacle height recognition system based on ultrasonic detection, characterized in that, include: An environmental correction module is used to obtain the installation height of the vehicle's ultrasonic radar and collect ambient temperature and humidity in real time, and correct the ultrasonic propagation speed based on the ambient temperature and humidity. The signal processing module is used to emit ultrasonic waves and collect echo signals, filter, calculate and determine the effective primary reflection signal and the effective secondary reflection signal from the echo signals, and record the propagation time of each; The distance calculation module is used to calculate the primary reflection distance and the secondary reflection distance based on the propagation time of the two and the corrected ultrasonic propagation speed. The height estimation module is used to calculate the estimated height of the obstacle based on a preset geometric relationship model, according to the installation height of the ultrasonic radar, the primary reflection distance, and the secondary reflection distance. The attitude correction module is used to obtain the real-time pitch angle of the vehicle body, and use the pitch angle to correct the attitude of the calculated height to obtain the final height of the obstacle. The classification decision module is used to compare the final height with a preset height and low obstacle threshold to determine the height and low classification attributes of the obstacle.

7. The system according to claim 6, characterized in that, The signal processing module includes: The time-domain filtering unit is used to calculate the actual time-domain values ​​of the primary reflection signal and the secondary reflection signal respectively, and further calculate the time difference Δt = |T – t| between the actual time-domain values ​​and the effective time-domain values ​​of the same type of reflection signal preset by the system. Where T represents the actual time-domain value of the primary reflection signal or the secondary reflection signal obtained by calculation, and t represents the effective time-domain value of the primary reflection signal or the secondary reflection signal preset by the system. When the time difference Δt is greater than the preset time-domain difference threshold, the corresponding reflection signal is judged as noise and discarded. An amplitude filtering unit is used to calculate the actual amplitude of the primary reflection signal and the secondary reflection signal respectively, and further calculate the amplitude ratio K = A / a between the actual amplitude and the effective amplitude of the same type of reflection signal preset by the system. Here, A represents the actual amplitude of the primary reflection signal or the secondary reflection signal, and a represents the effective amplitude of the primary reflection signal or the secondary reflection signal preset by the system. When the amplitude ratio K is less than the preset amplitude threshold, the corresponding reflection signal is judged as noise and discarded.

8. The system according to claim 7, characterized in that, The height calculation module includes: The high obstacle calculation unit is used to calculate the obstacle height when it is determined that the obstacle height is higher than the installation height of the ultrasonic radar, based on the formula. and Derivation: And according to the formula Calculate the height of obstacles ; The low obstacle calculation unit is used to calculate the obstacle height when it is determined to be lower than the installation height of the ultrasonic radar, based on the formula... and Derivation: And according to the formula Calculate the height of obstacles ; Where d1 and d2 are the primary reflection distance and secondary reflection distance corresponding to the primary reflection signal and the secondary reflection signal, respectively, D is the horizontal distance between the obstacle and the vehicle, Δh is the difference between the height of the obstacle and the installation height of the ultrasonic radar, and h0 is the installation height of the ultrasonic radar.

9. The system according to claim 8, characterized in that, in: In the environmental correction module, the formula for correcting the ultrasonic wave propagation speed V according to the following formula is: Where T is the ambient temperature and H is the ambient humidity; In the attitude correction module, the height information is corrected using the following formula to obtain the true height of the obstacle, Hobj: Hobj = ΔHobj × cosα, where α is the real-time pitch angle of the vehicle body.

10. The system according to claim 8, characterized in that, The classification decision module is specifically used to: preset multiple height threshold intervals, compare the final height Hobj with the height threshold intervals, and output the height attribute classification of the obstacle; the height threshold intervals include: low obstacle interval (Hobj<0.5m), medium obstacle interval (0.5m ≤Hobj<1.2m), and large obstacle interval (Hobj ≥ 1.2m).

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