Ultrasonic Sensor Echo Amplitude Filtering for Parking Obstacle Detection
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Solution Overview
Problem
Existing driver assistance systems using ultrasonic sensors for parking aids face challenges in reliably masking out irrelevant objects like trailer hitches, which can lead to real obstacles being hidden from the driver, especially when the vehicle is stationary and not moving.
Innovation Solution
A method that checks both the time window and amplitude criteria of the echo received by the sensor to distinguish between irrelevant objects and real obstacles, ensuring that only relevant objects are displayed to the driver by interpreting echoes within a specified time window and amplitude range as coming from irrelevant objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a distance range is masked out to hide the trailer hitch, then the irrelevant object is successfully hidden, but real obstacles in the same distance range are also hidden
Solution Approach 1:
The patent applies local quality by differentiating the treatment of echoes based on their specific characteristics. Instead of uniformly masking all echoes within a distance range, the system evaluates each echo's amplitude and time characteristics individually. This allows the system to selectively mask only those echoes that match the trailer hitch profile while preserving echoes from real obstacles, even if they are at the same distance.
Solution Approach 2:
The patent changes the parameter of echo evaluation from purely time-based masking to a combined amplitude and time window analysis. By introducing amplitude as an additional parameter for discrimination, the system can distinguish between the trailer hitch echo and real obstacle echoes that arrive at similar times, thereby resolving the contradiction between hiding irrelevant objects and detecting real obstacles.
2Reliability
If reception sensitivity for close range is drastically reduced, then the trailer hitch is no longer detected, but real obstacles in the close range are also not detected
Solution Approach 1:
Instead of uniformly reducing reception sensitivity across all close-range echoes, the patent applies local quality by evaluating each echo's amplitude characteristics. The system maintains high reception sensitivity overall but selectively identifies and masks only those echoes that exhibit the specific amplitude characteristics of the trailer hitch, thereby preserving detection precision for real obstacles.
Solution Approach 2:
The patent changes the approach from reducing sensitivity (a global parameter change) to amplitude-based discrimination (a local parameter evaluation). By analyzing the amplitude parameter of each echo within a time window, the system can maintain high sensitivity for detecting real obstacles while reliably identifying and masking the trailer hitch echo based on its distinct amplitude signature.
3Reliability
If all reflections within a certain distance range are suppressed, then the trailer hitch is hidden, but the system cannot distinguish between irrelevant objects and real obstacles
Solution Approach 1:
The patent introduces amplitude as an additional evaluation parameter beyond simple time-based masking. By analyzing both the time window and amplitude characteristics of each echo, the system creates a more sophisticated discrimination mechanism that can reliably distinguish between the trailer hitch and real obstacles without requiring complex additional hardware or processing systems.
Solution Approach 2:
The patent creates a virtual model or signature of the trailer hitch echo based on its characteristic amplitude and time properties. This copied profile is then used to identify and mask similar echoes, while echoes that deviate from this profile (even if they occur at the same time) are preserved as potential real obstacles, simplifying the discrimination process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for precise and reliable masking of irrelevant objects, enabling the detection and display of real obstacles even when they are at the same distance as trailer hitches, thereby improving the accuracy of the parking assistance system.
Implementation Method 1
The transmitted signal then reflects off obstacles and is received again by the ultrasonic sensor, namely as an echo.
Implementation Method 2
In the present case, the interest is in a parking aid for a motor vehicle, in which ultrasonic sensors are used to detect obstacles external to the vehicle.
Data Source
Figure 1~2
Figure 3~4
AI summary
This paper presents a solution for reliably filtering out an irrelevant object (16) and detecting a real obstacle (21) using an ultrasonic sensor. In this method, a transmission signal is sent by a sensor (12 to 15) at a transmission time (tS), and an echo (23) is received at a reception time (tE). The system checks whether the reception time (tE) lies within a predetermined time window (T) relative to the transmission time (tS). It also checks whether a predetermined criterion regarding the amplitude (A) of the echo (23) is met, specifically whether a maximum (M) of the echo (23) lies within a predetermined value range (W). The echo (23) is interpreted as belonging to the irrelevant object (16) if the reception time (tE) lies within the predetermined time window (T) and the criterion is also met.