In-Vehicle Voice Recognition Echo Cancellation via Analog Signal Pre-Processing
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Solution Overview
Problem
In-vehicle voice recognition systems face challenges in achieving effective echo cancellation due to the physical distance between the external amplifier and the microphone, which hinders the timely acquisition of the final media signal needed for accurate voice command recognition, especially in noisy vehicle environments.
Innovation Solution
The implementation of an in-vehicle voice recognition apparatus with eco cancellation hardware that directly receives the analog signal from the digital signal processor, allowing it to acquire a final media output prior to the microphone input by applying suitable equalizer logic, thereby enabling effective echo cancellation regardless of the physical distance between components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the external amplifier is disposed at a physical distance from the head unit and microphone (general vehicle audio hardware arrangement), then the system layout flexibility is improved, but the echo cancellation performance deteriorates due to delayed acquisition of final media signal
Solution Approach 1:
The eco cancellation hardware acquires and processes the final media signal in advance before it reaches the microphone. By performing preliminary processing of the analog signal from the DSP, the system prepares the reference signal for echo cancellation beforehand, ensuring accurate separation of voice commands from media sound even when physical distances between components vary
Solution Approach 2:
The eco cancellation hardware acts as an intermediary component that directly receives the analog signal from the DSP and generates the reference signal for echo cancellation. This intermediary position allows the system to decouple the timing relationship from physical distance, as the reference signal is generated based on the actual media signal path rather than relying on fixed spatial relationships
2Ease of manufacture
If the final media signal is acquired after microphone input (due to physical distance), then hardware installation simplicity is improved, but the voice recognition accuracy deteriorates
Solution Approach 1:
The system performs preliminary acquisition and processing of the final media signal through the DSP and eco cancellation hardware before the microphone captures the mixed signal. This preliminary action ensures that the reference signal for echo cancellation is ready in advance, enabling accurate voice command separation without requiring complex hardware reconfiguration
Solution Approach 2:
The eco cancellation hardware uses the acquired final media signal as feedback to generate a reference signal that is fed back into the voice recognition process. This feedback mechanism allows the system to continuously adjust and cancel echo based on the actual media output, improving voice recognition accuracy while maintaining simple hardware installation
Data Source
AI summary
An in-vehicle voice recognition apparatus capable of recognizing user voice more correctly by removing sound generated in a vehicle from sound input to a microphone, and a method of controlling the same are disclosed. The in-vehicle voice recognition apparatus according to an embodiment of the present disclosure includes a central processing unit configured to output a media signal, a digital signal processor configured to receive the media signal from the central processing unit and to convert the media signal into an analog signal, and an eco cancellation hardware connected to the digital signal processor and configured to receive the analog signal, to acquire a first final media output on the basis of the analog signal and to acquire a voice command from a sound input through a microphone on the basis of the first final media output.