Terminal Sound Processing Using Interaural Level Difference

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing sound processing systems face challenges in accurately picking up target sound signals during video capturing due to severe noise mixing, leading to low pickup precision of the target sound source, especially in scenarios with a low signal-to-noise ratio.

Innovation Solution

A sound processing method and apparatus utilizing two microphones located on the front and back surfaces of a terminal, which calculates the interaural level difference in sound signals to determine if a backward sound signal is present and filters it out, ensuring that only sound within the photographing range is captured.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional beamforming technology is used for sound source positioning, then directional sound pickup is achieved, but noise from opposite direction (backward sound) mixes with target sound, reducing pickup precision

Engineering Contradiction:
Improvesound source positioning precisionVSAvoidbackward noise interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent divides the sound field into front and back directions by using two separate microphones positioned at the front and back of the terminal. This segmentation allows independent processing of sounds from different directions, enabling the system to identify and separate backward noise from the target forward sound, thereby resolving the mixing problem in conventional beamforming.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different processing strategies to sounds from different directions. By calculating the interaural level difference (ILD) specifically for backward directions and comparing it with forward microphone signals, the system applies noise suppression selectively to backward sounds while preserving forward target sounds, achieving local quality optimization for different spatial regions.

Inventive Principle:
Principle #3Local quality

2Reliability

If fixed beam or adaptive beam is used to reduce interference, then directional pickup is improved, but noise in low signal-to-noise ratio scenarios still contaminates the captured sound

Engineering Contradiction:
Improveinterference suppression capabilityVSAvoidtarget sound pickup precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary classification of sound directions by calculating the interaural level difference before applying noise suppression. By identifying backward sounds in advance through ILD calculation and comparing with forward microphone signals, the system prepares the sound signals for selective processing, ensuring that noise suppression is applied only where needed rather than uniformly across all directions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent dynamically adjusts noise suppression based on real-time ILD calculations and sound direction identification. Rather than using a fixed suppression level, the system adapts its processing gain dynamically by comparing backward and forward sound signals frame by frame, allowing optimal noise reduction while preserving target sounds in varying acoustic environments.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3531674B1Sound processing method and device
Publication Date: 2024.02.14 HUAWEI TECH CO LTD
  • EP3531674B1 patent drawingFigure 1~2A
  • EP3531674B1 patent drawingFigure 2B~2C
  • EP3531674B1 patent drawingFigure 3

AI summary

The present invention discloses a sound processing method and apparatus. The method is applied to a terminal having two microphones at the top, the two microphones are respectively located on a front surface and a back surface of the terminal, and the method includes: when it is detected that a camera of the terminal is in a photographing state, acquiring sound signals of a current frame by using the two microphones; calculating an interaural level difference between the two microphones based on the sound signals of the current frame according to a first preset algorithm; determining whether the interaural level difference satisfies a sound source direction determining condition; if the determining condition is satisfied, determining, based on the interaural level difference, whether the sound signals of the current frame include a backward sound signal, where the backward sound signal is a sound signal whose sound source is located at the back of the camera; and if it is determined that the sound signals of the current frame include the backward sound signal, filtering out the backward sound signal from the sound signals of the current frame. In this way, in a scenario of a low signal-to-noise ratio, sound source positioning is performed based on an interaural level difference, so that pickup precision of a sound source within a photographing range can be improved.