Siren Detection Using Multi-Window Audio Segmentation

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Solution Overview

Problem

Existing audio detection systems in autonomous vehicles face challenges in quickly and accurately identifying sirens amidst background noise, particularly in environments with low signal-to-noise ratios, due to the trade-off between analysis speed and accuracy.

Innovation Solution

The system processes audio signals by creating windowed samples of varying lengths, using mel-frequency cepstrum coefficients (MFCCs), monotonicity estimation, and spectral energy concentration to detect sirens, with a classifier operating on shorter samples for quick identification and falling back on longer samples for accuracy, and adapting based on training data and internet updates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If longer audio samples are processed for more accurate siren identification, then measurement precision is improved, but productivity deteriorates due to increased processing time

Engineering Contradiction:
Improvesiren identification accuracyVSAvoidprocessing speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The audio processing system segments the audio signal into multiple windowed samples of different lengths (e.g., 10ms, 30ms, 50ms, 100ms windows). Shorter windows enable faster initial detection, while longer windows provide more accurate classification. This segmentation allows the system to process multiple time scales simultaneously, resolving the contradiction between speed and accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the processing strategy based on the detection results. When a siren is detected in a short window, the system can trigger further analysis with longer windows to confirm the detection. This dynamic adaptation allows the system to optimize processing time for each specific audio segment while maintaining high accuracy.

Inventive Principle:
Principle #15Dynamics

2Productivity

If shorter audio samples are processed for faster analysis, then productivity is improved, but measurement precision deteriorates due to limited information

Engineering Contradiction:
Improveanalysis speedVSAvoidfeature identification accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system processes audio at multiple temporal resolutions by creating windowed samples of different lengths. Short windows (10-30ms) provide rapid initial analysis for quick detection, while longer windows (50-100ms) are processed to extract more reliable acoustic features. This multi-scale segmentation ensures both speed and precision are achieved through parallel processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary analysis on short audio windows to quickly identify potential siren candidates. This preliminary action filters out non-siren sounds early, allowing the system to focus computational resources on promising candidates using longer windows for definitive classification, thus maintaining both speed and accuracy.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If multiple windowed audio samples of different lengths are processed, then measurement precision is improved through more information, but device complexity increases

Engineering Contradiction:
Improvedetection reliabilityVSAvoidprocessing system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system segments audio processing into distinct stages with different window lengths, where each stage serves a specific purpose. Short windows handle rapid detection, medium windows provide confirmation, and long windows ensure accuracy. This structured segmentation manages complexity by organizing multiple processing paths into a coherent hierarchical framework.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The same audio processing pipeline and feature extraction algorithms are reused across different window lengths, making the system multi-functional. A single classifier can operate on multiple time scales, reducing the need for separate specialized processors for each window size and thereby managing system complexity while maintaining detection reliability.

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

Data Source

PatentUS10140998B2Method for siren detection based on audio samples
Publication Date: 2018.11.27 WAYMO LLC
  • US10140998B2 patent drawing
  • US10140998B2 patent drawing
  • US10140998B2 patent drawing

AI summary

The present disclosure provides methods and apparatuses that enable an apparatus to identify sounds from short samples of audio. The apparatus may capture an audio sample and create several audio signals of different lengths, each containing audio from the captured audio sample. The apparatus my process the several audio signals in an attempt to identify features of the audio signal that indicate an identification of the captured sound. Because shorter audio samples can be analyzed more quickly, the system may first process the shortest audio samples in order to quickly identify features of the audio signal. Because longer audio samples contain more information, the system may be able to more accurately identify features in the audio signal in longer audio samples. However, analyzing longer audio signals takes more buffered audio than identifying features in shorter signals. Therefore, the present system attempts to identify features in the shortest audio signals first.