Multichannel Dialogue Projection Using Single-Channel Separation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for multichannel dialogue separation face challenges such as inter-channel phase distortions, computational complexity, and the need for extensive training data, making it difficult to effectively separate dialogue from background signals in audio mixtures with arbitrary numbers of channels.

Innovation Solution

The Automatic Signal Projection (ASIP) method downmixes multichannel audio to a single channel, applies monaural separation, and estimates projection coefficients using a Kalman-like filter to reconstruct the dialogue signal across channels, minimizing computational cost and phase distortions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multichannel dialogue separation is performed using traditional methods, then dialogue can be separated from background signals, but inter-channel phase distortions occur and spatial integrity is compromised

Engineering Contradiction:
Improvedialogue separation accuracyVSAvoidinter-channel phase distortions
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The method segments the multichannel separation task into two independent parts: (1) single-channel separation applied uniformly across all channels to extract dialogue magnitude, and (2) projection coefficient estimation to reconstruct spatial positions. This segmentation prevents inter-channel phase distortions by avoiding channel-specific processing while maintaining spatial integrity through the projection step.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces projection coefficients as an intermediary element that bridges the single-channel separation output and the multichannel reconstruction. These coefficients capture spatial information without introducing phase distortions, acting as a mediator that preserves spatial integrity while enabling multichannel dialogue separation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multichannel separation methods are used to handle arbitrary channel configurations, then adaptability increases, but computational complexity and training data requirements increase significantly

Engineering Contradiction:
Improvechannel configuration adaptabilityVSAvoidcomputational complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The method achieves universality by designing a single-channel separation pipeline that can be applied to any number of channels through the projection coefficient mechanism. The same core separation model works for stereo, 5.1, 7.1, or arbitrary channel configurations, eliminating the need for separate multichannel training data and reducing computational complexity while maintaining adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If single-channel separation methods are applied directly to multichannel mixtures, then computational cost is reduced, but spatial information and channel-specific characteristics are lost

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidspatial information
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent resolves this contradiction by operating in a different dimension - instead of processing each channel separately or using complex multichannel models, it applies single-channel separation to the magnitude spectrum and recovers spatial information through projection coefficients. This dimensional transformation allows efficient single-channel processing while preserving multichannel spatial characteristics.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4651128A1Automatic signal projection for multichannel dialogue separation
Publication Date: 2025.11.19 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP4651128A1 patent drawingFigure 1
  • EP4651128A1 patent drawingFigure 2
  • EP4651128A1 patent drawingFigure 3

AI summary

There is disclosed, inter alia, a system (1) for deriving, from an input multi-channel audio signal (2), a multi-channel target signal (4) in compressed form, the system (1) comprising: a downmix block (10), to downmix the input multi-channel audio signal (2) onto one single-channel downmix signal (12); a single-channel separation block (20), to perform a single-channel separation of the single-channel downmix channel (12), to derive a single-channel target signal (22) from the single-channel audio signal (12), a multi-channel projection coefficients estimation block (40), to derive an array of multi-channel projection coefficients (32) capable of projecting the single-channel target signal (22) onto multiple channels; and an output unit (30) to output the multi-channel target signal (4) in compressed form as the single-channel target signal (22) and the array of multi-channel projection coefficients (32).