Distributed Mobile Audio Capture via Spatial Segmentation
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Solution Overview
Problem
Mobile devices face challenges in capturing multichannel audio and video due to their small size, leading to poor spatial separation of microphones, which results in artifacts such as poor envelopment, low signal-to-noise ratio, and limited flexibility in recording spacious-sounding audio and 3D video, as well as increased processing requirements and costs.
Innovation Solution
A method and apparatus that utilize multiple distinct mobile devices to record and combine acoustic signals from multiple channels, allowing for optimal spacing of microphones and cameras, thereby enhancing the quality of multichannel audio and video recordings by synchronizing and processing the signals at a centralized entity, such as a web server, to create a unitary multi-channel file.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple microphones are placed on a single mobile device, then the device can record multichannel audio, but the microphones are constrained to close spacing (5-15 cm) which degrades audio quality
Solution Approach 1:
The patent divides the audio recording system into multiple independent mobile devices, each equipped with one or more microphones. Instead of requiring all microphones to be on a single device, the system segments the microphone array across multiple devices that can be positioned apart from each other, achieving both multichannel capability and adequate spacing.
Solution Approach 2:
The patent transitions from a two-dimensional arrangement of microphones on a single device surface to a three-dimensional spatial distribution of microphones across multiple devices. This allows microphones to be separated by several meters in 3D space while maintaining the ability to record multiple audio channels simultaneously.
2Volume of moving object
If microphones are spaced close together on a single device, then the device size remains small, but the signal-to-noise ratio decreases due to extensive processing requirements
Solution Approach 1:
The patent segments the recording system across multiple devices, allowing each device to remain compact while the distributed microphone array provides sufficient spacing. This segmentation enables adequate microphone separation without requiring a single large device, thereby maintaining high signal-to-noise ratio while preserving portability.
3Ease of operation
If steering algorithms are used to achieve channel separation, then reasonable separation between channels can be achieved, but processing artifacts arise when multiple sound sources are present
Solution Approach 1:
The patent uses the third dimension (spatial separation between devices) to achieve channel separation physically, rather than relying solely on algorithmic steering in the audio signal domain. By positioning microphones on multiple devices at different locations, the system achieves natural spatial separation that reduces the need for aggressive steering algorithms and minimizes processing artifacts.
4Adaptability or versatility
If algorithms are used to alter directional patterns and delays, then some flexibility can be achieved, but the flexibility is limited within reasonable bounds
Solution Approach 1:
The patent creates a dynamic and flexible system where the physical positions of multiple devices can be adjusted during recording sessions. This dynamic repositioning of devices provides unlimited flexibility in achieving desired directional patterns and spatial arrangements, surpassing the fixed limitations of algorithm-based adjustments on a single device.
Data Source
AI summary
At a master device are registered one or more other devices associated with one or more audio channels for recording at least one acoustic signal from one or more sound sources. The at least one acoustic signal is recorded using at least one of the master device and one or more other devices, and the at least one recorded acoustic signal is either collected by at least one of the master device and the one or more other devices, or transmitted to another entity by at least one of the master device and the one or more other devices. In the examples the registration assigns audio and/or video channels to different microphones of the different devices. In one embodiment these different recordings are mixed at the master device and in another they are mixed at a web server into a multi-channel audio/sound (or audio-video) file.