Presence Detection Using Ambient Acoustic Triangulation
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Solution Overview
Problem
Existing presence detection systems using ultrasound are prone to interference, high power consumption, and intermodulation effects, especially in noisy environments, and require active transmitters and receivers.
Innovation Solution
A presence detection system utilizing at least two microphones connected to a processor that analyzes acoustic signals from environmental sources, including audible and inaudible sounds, to identify user presence by comparing direct and reflected signals, with the ability to filter and triangulate sound sources for accurate detection, and optionally using on-device training for user identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active ultrasound transmitters and receivers are used for presence detection, then detection capability is improved, but power consumption increases
Solution Approach 1:
The system uses existing ambient acoustic signals from the environment (other devices, objects, living things) as the detection source, eliminating the need for a dedicated active transmitter. The microphones passively receive and analyze these self-generated environmental sounds, allowing presence detection without additional power-consuming transmission hardware.
Solution Approach 2:
The microphones already present in the device for other functions (audio input, noise cancellation, etc.) are repurposed for presence detection. This multi-functional use of existing components eliminates the need for separate dedicated detection hardware, reducing overall power consumption while maintaining detection capability.
2Reliability
If active ultrasound transmitters are used for presence detection, then detection capability is improved, but interference and noisy environments worsen
Solution Approach 1:
The system converts the harmful effect of ambient noise and acoustic interference into a beneficial resource for detection. By analyzing the acoustic signatures and reflections within the noisy environment, the system identifies presence and position of users, turning the previously problematic noise into useful detection data.
Solution Approach 2:
The system uses acoustic reflections from objects and surfaces in the environment as intermediaries to detect user presence. Instead of directly transmitting through noisy channels, the system analyzes how ambient sounds reflect off users and objects, using these reflections as mediator signals that carry presence information despite the noisy environment.
3Measurement precision
If multiple microphones are used for triangulation and accurate detection, then detection precision is improved, but device complexity increases
Solution Approach 1:
The system repurposes existing microphones in the device (already present for audio input, voice processing, and noise cancellation functions) for presence detection and triangulation. This eliminates the need for adding separate dedicated detection microphones, maintaining detection precision while avoiding increased device complexity.
Solution Approach 2:
The system merges presence detection functionality with existing audio processing functions. The same microphones and signal processing pipelines used for voice input and noise cancellation are simultaneously utilized for acoustic triangulation and presence detection, combining multiple functions into a unified system that reduces overall complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces power consumption and improves detection accuracy by leveraging ambient acoustic signals, allowing for efficient presence detection and user identification with reduced noise interference and increased resolution.
Implementation Method 1
at least two microphones (1) being connected through an interface (4) to a processor (9)
Implementation Method 2
The processor 9 is configured to analyze the frequency, phase and amplitude of the acoustic signal received by the microphones 1
Data Source
AI summary
The present invention relates to a presence detecting electronic device as well as a method for using the device. The device including at least one microphone configured to receive acoustic signals from the environment, and a processor connected to the microphone for analyzing the received signal. The device also includes means for directly detecting the transmitted signal from an acoustic source and comparing the directly transmitted signal with the received signal for identifying if an object or user in the vicinity of the device based on the comparison between the transmitted and the reflected signal.