Warped Spectral Audio Encoding for Speech Recognition and Reconstruction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing voice codecs and speech recognition systems have limited success when attempting to use encoded speech recognition features to construct audio signals or vice versa, resulting in reconstructed audio signals that are not close representations of the original.

Innovation Solution

The use of a warped spectral estimate of an original audio signal to encode fine features, which can be used for speech recognition and to reconstruct a reconstructed audio signal that approximates the original, involves encoding and decoding representations of warped frequency spectral estimates and fine estimates, with dynamic range reduction and expansion operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If encoded speech recognition features are used to construct audio signals, then speech recognition performance is improved, but the reconstructed audio signal quality deteriorates

Engineering Contradiction:
Improvespeech recognition performanceVSAvoidreconstructed audio signal quality
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The audio signal representation is segmented into two distinct components: warped spectral estimates (for speech recognition) and fine estimates (for audio reconstruction). This segmentation allows each component to be optimized for its specific purpose without compromise, resolving the contradiction between speech recognition performance and audio signal quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Fine estimates serve as an intermediary component that bridges the gap between warped spectral estimates and reconstructed audio signals. By introducing this intermediate representation, the system can achieve both accurate speech recognition and high-quality audio reconstruction, as the fine estimates provide the additional detail needed for faithful signal reproduction.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If encoded voice codec features are used for speech recognition, then audio signal quality is preserved, but speech recognition performance deteriorates

Engineering Contradiction:
Improveaudio signal qualityVSAvoidspeech recognition performance
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The system segments the feature extraction process into two parallel paths: one generating warped spectral estimates optimized for speech recognition, and another generating fine estimates optimized for audio reconstruction. This segmentation eliminates the need to compromise either speech recognition performance or audio signal quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The encoding system becomes universal by producing multiple types of representations from the same input audio signal. The warped spectral estimates serve speech recognition functions while the fine estimates serve audio reconstruction functions, allowing the system to fulfill multiple purposes simultaneously without degradation in either domain.

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

3Device complexity

If a single encoding scheme is used for both speech recognition and audio reconstruction, then system complexity is reduced, but both speech recognition performance and audio reconstruction quality deteriorate

Engineering Contradiction:
Improveencoding system complexityVSAvoidaudio reconstruction quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The encoding system is segmented into two specialized sub-systems: a warped spectral estimation sub-system for speech recognition and a fine estimation sub-system for audio reconstruction. While this increases overall system complexity compared to a single scheme, it dramatically improves both speech recognition performance and audio reconstruction quality by allowing each sub-system to be optimized for its specific function.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS8532985B2Warped spectral and fine estimate audio encoding
Publication Date: 2013.09.10 MICROSOFT TECHNOLOGY LICENSING LLC
  • US8532985B2 patent drawing
  • US8532985B2 patent drawing
  • US8532985B2 patent drawing

AI summary

A warped spectral estimate of an original audio signal can be used to encode a representation of a fine estimate of the original signal. The representation of the warped spectral estimate and the representation of the fine estimate can be sent to a speech recognition system. The representation of the warped spectral estimate can be passed to a speech recognition engine, where it may be used for speech recognition. The representation of the warped spectral estimate can also be used along with the representation of the fine estimate to reconstruct a representation of the original audio signal.