In-Vehicle Sound Localization via Transfer Function Filtering
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Solution Overview
Problem
In-car communication systems fail to intuitively distinguish between multiple talkers, making it difficult to determine who is speaking during conversations within and outside a vehicle.
Innovation Solution
A sound collection loudspeaker apparatus is installed in a vehicle with multiple sound collection and amplification positions, using transfer functions and filters to localize sound images at specific positions, allowing enhanced signals to be output to speakers and distinguishing between talkers by localizing sound images at separate locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If speakers are installed near the ears for voice amplification, then voice presentation efficiency is improved, but sound source localization capability deteriorates
Solution Approach 1:
The patent transitions from a single-dimension audio playback approach to a multi-dimensional sound field control system. By installing multiple speakers at different positions (front, rear, left, right) and using transfer function multiplication to control sound propagation in three-dimensional space, the system achieves both efficient voice delivery and accurate sound source localization. The sound image is positioned in spatial dimensions rather than just being amplified near the ear.
Solution Approach 2:
The patent divides the voice amplification function into multiple independent speaker channels, each responsible for a specific spatial zone. Instead of using a single speaker near the ear, the system segments the audio output across multiple speakers (front speaker, rear speaker, left speaker, right speaker) and uses transfer function multiplication to control each segment's contribution to the overall sound image, enabling both efficient delivery and accurate localization.
2Adaptability or versatility
If multiple talkers are amplified through the same speaker position, then conversation coverage is improved, but talker distinction capability deteriorates
Solution Approach 1:
The patent applies different transfer function filters to different talker signals based on their spatial origins. Each talker's voice is processed with a specific filter that corresponds to their location (front seat, rear seat, left side, right side), creating locally optimized sound images for each talker. This allows multiple talkers to be amplified simultaneously while maintaining distinct spatial characteristics for each, enabling conversation coverage and talker distinction simultaneously.
Solution Approach 2:
The patent introduces transfer function multiplication as an intermediary processing step between voice collection and speaker output. This intermediary filter acts as a spatial mediator that transforms the raw voice signals into localized sound images, allowing the system to maintain both broad conversation coverage and clear talker distinction by mediating the spatial relationship between multiple talkers and the speaker system.
3Ease of operation
If sound is collected from front seat and played to rear seat, then in-car communication function is improved, but intuitive talker identification deteriorates
Solution Approach 1:
The patent solves the talker identification problem by adding spatial dimensionality to the audio transmission. Instead of simply playing back sound from the front seat to the rear seat through a single channel, the system uses transfer function multiplication to create a virtual sound image that maintains the spatial relationship between the talker and the listener. The rear seat passenger perceives the sound as coming from the front direction, enabling intuitive talker identification while maintaining effective in-car communication.
Data Source
AI summary
Provided is a sound collection loudspeaker apparatus that makes it possible to intuitively distinguish which talker is talking, and improve the comfort of conversations, when performing in-vehicle conversation and conversations with people outside of a vehicle. The sound collection loudspeaker apparatus is installed in a vehicle. Two or more sound collection and amplification positions are assumed to be present inside the vehicle. The apparatus includes: a transfer function multiplying unit that, from a transfer function for transfer from a desired sound source position where a sound image of an enhanced signal is localized to both ears of a target person located at the sound collection and amplification position, and a transfer function for transfer from one or more speakers installed for playing back sound at the sound collection and amplification position to the ears, applies a filter for localizing a sound image at the sound source position to an enhanced signal, and outputs the enhanced signal that has been filtered to the speaker. The enhanced signal is a signal in which a target sound emitted from the sound collection and amplification position has been enhanced from a signal collected by the one or more microphones.