Vehicle ANC Controller Using Virtual Error Microphone for Voice Recognition
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Solution Overview
Problem
Voice recognition systems in vehicles are susceptible to environmental noise, leading to incorrect recognition and false positives due to the vehicle's noisy cabin, which existing active noise cancellation implementations fail to address effectively globally within the cabin.
Innovation Solution
A vehicle active noise cancellation apparatus and method that includes an ANC controller coupled with error microphones to generate a noise cancellation wave and apply correction filters to remove environmental noise and noise cancellation waves at the voice recognition microphone, using a tuning phase to estimate noise patterns and generate filters that minimize noise capture by positioning error microphones near the voice recognition microphone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If existing ANC implementations with error microphones are used to reduce environmental noise, then noise reduction is achieved at spots directly under the error microphone, but noise propagation to the VR microphone is not prevented
Solution Approach 1:
A virtual error microphone is introduced as an intermediary element. This virtual microphone is created by combining outputs from multiple physical error microphones through correction filters, allowing it to sense noise conditions at the VR microphone location without requiring a physical microphone to be positioned there. This intermediary enables global noise cancellation across the cabin while protecting voice recognition accuracy.
Solution Approach 2:
Existing error microphones in the ANC system are made multi-functional. They serve both their original purpose of measuring noise for ANC purposes and additionally contribute to creating a virtual error microphone that protects the VR microphone. This universal use of existing components eliminates the need for additional microphones while achieving both noise reduction and voice recognition protection.
2Object-affected harmful factors
If a virtual error microphone is created by combining outputs from multiple physical error microphones, then global noise cancellation is achieved, but system complexity increases
Solution Approach 1:
The system makes existing ANC components serve multiple functions. The same error microphones and correction filters used for standard ANC operations are also utilized to create the virtual error microphone. This multi-functionality approach achieves global noise cancellation without adding new physical components, thereby limiting the increase in system complexity.
Solution Approach 2:
The ANC system creates its own virtual error microphone using its existing resources (physical error microphones and correction filters). The system serves itself by generating the virtual microphone signal internally without requiring external additional components. This self-service capability achieves global noise protection while keeping the system architecture relatively simple.
3Measurement precision
If correction filters are applied to the virtual error microphone output, then noise and noise cancellation wave removal is improved, but processing complexity increases
Solution Approach 1:
Correction filters are pre-calculated and stored during a tuning phase before actual operation. During normal voice recognition and noise cancellation operations, these pre-computed filters are simply applied to the virtual error microphone signal without requiring real-time complex calculations. This preliminary preparation improves measurement precision while keeping runtime processing complexity manageable.
Solution Approach 2:
The system creates a copied or simulated error microphone signal (virtual error microphone) that replicates the noise conditions at the VR microphone location. This virtual copy allows for accurate noise measurement and filtering without requiring physical modification of the VR microphone or its surroundings. The copying approach improves measurement accuracy while maintaining relatively simple processing.
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
Effectively reduces environmental noise and noise cancellation waves at the voice recognition microphone, improving voice recognition performance without adding cost to the voice recognition system and allowing existing error microphones to be used for both tuning and production phases.
Implementation Method 1
The ANC controller is configured to receive a first signal indicative of environmental noise that propagates through a vehicle cabin and that is received at a voice recognition (VR) microphone and to generate a noise cancellation wave to remove the environmental noise
Implementation Method 2
The ANC controller is configured to receive an audio output from the at least one error microphone that is at least indicative of the environmental noise and the noise cancellation wave received at the VR microphone and to apply at least one correction filter to the audio output to remove the environmental noise and the noise cancellation wave
Data Source
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AI summary
In at least one embodiment, a vehicle active noise cancellation (ANC) apparatus including an ANC controller is disclosed. The ANC controller is operably coupled to at least one error microphone (EM1, EM2, EMn). The ANC controller is configured to receive (50) a first signal indicative of environmental noise that propagates through a vehicle cabin and that is received at a voice recognition microphone (VRM) and to generate (20) a noise cancellation wave to remove the environmental noise, the noise cancellation wave being received at the VR microphone (VRM). The ANC controller is configured to receive an audio output from the at least one error microphone that is at least indicative of the environmental noise and the noise cancellation wave received at the VR microphone and to apply at least one correction filter (CF1, CF2, CFn) to the audio output to remove the environmental noise and the noise cancellation wave that is received at the VR microphone.