Ultrasonic Noise Removal via Correlation Detection
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Solution Overview
Problem
Conventional ultrasonic systems face performance degradation due to system delay caused by distinguishing external noise from reception signals, leading to incorrect alarms and delayed object recognition, especially in high-speed vehicle applications.
Innovation Solution
An ultrasonic system employing a correlation detector using a correlation function to differentiate between normal signals and noise, even with frequency shifts, by transmitting a frequency modulation signal to maintain signal correlation and reduce Doppler phenomenon effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If signal transmission and reception are performed twice to distinguish external noise from received signal, then noise recognition accuracy is improved, but system delay increases causing performance degradation
Solution Approach 1:
The patent applies preliminary action by performing noise identification during the first signal transmission and reception, rather than requiring a second transmission. The correlation detector calculates correlation between transmission and reception signals in real-time, enabling noise distinction to be completed before any potential second transmission would occur, thus eliminating the time loss associated with repeated transmissions.
Solution Approach 2:
The patent replaces the mechanical approach of repeated physical transmissions with a signal processing-based correlation detection method. Instead of mechanically transmitting signals multiple times to identify noise, the system uses mathematical correlation analysis to distinguish noise from valid signals during a single transmission cycle, substituting physical repetition with computational analysis.
2Device complexity
If Band Pass Filter is used to remove external noise, then noise removal is simplified, but external noise within BPF frequency range is incorrectly recognized as normal signal
Solution Approach 1:
The patent merges the noise removal function with the signal processing chain by integrating a correlation detector between the Band Pass Filter and subsequent processing stages. This combination allows the system to maintain the simplicity of BPF-based noise removal while adding correlation-based verification to prevent misidentification of noise within the passband, achieving both simplicity and accuracy through functional integration.
Solution Approach 2:
The correlation detector serves as an intermediary component between the Band Pass Filter and the signal interpretation stage. It mediates between the filtered signal and the final recognition decision, providing an additional verification layer that prevents incorrect identification of noise as valid signals while maintaining the overall system architecture and not requiring complete redesign of the noise removal approach.
3Productivity
If conventional ultrasonic system processes signals, then basic object detection is achieved, but system delay causes delayed object recognition in high-speed applications
Solution Approach 1:
The patent ensures continuity of useful action by performing correlation detection continuously during the normal signal reception process rather than as a separate post-processing step. The correlation calculation occurs in real-time as part of the signal processing chain, maintaining uninterrupted operation and eliminating additional time delays that would result from sequential processing stages.
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 enhances robustness against external noise and Doppler effects, allowing for accurate signal differentiation and improved system performance with single-time transmission and reception, reducing false alarms and maintaining accurate object recognition.
Implementation Method 1
transmitting a transmission signal to a medium and receiving a reception signal reflected from the medium
Implementation Method 2
calculating a correlation between the transmission signal and a signal in the frequency range recognized as the normal signal in the reception signal
Implementation Method 3
maintain correlation between the transmission signal and a reception signal despite a frequency shift phenomenon in the reception signal, to maintain robustness against a Doppler phenomenon
Implementation Method 4
A frequency modulation signal whose frequency changes over time may be used as the transmission signal
Data Source
AI summary
An apparatus and method for removing noise of an ultrasonic system to improve robustness against noise by removing external noise from a reception signal reflected from an object are provided. The method includes transmitting, by a sensor, a transmission signal to a medium and receiving a reception signal reflected from the medium. A controller is configured to remove noise from a frequency range recognized as a normal signal from the reception signal and calculate a correlation between the transmission signal and a signal in the frequency range recognized as the normal signal in the reception signal. In addition, the controller is configured to determine whether the signal in the frequency range recognized as the normal signal is the normal signal or noise based on the calculated correlation.