WiFi Triangulation for Continuous Person Tracking

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Solution Overview

Problem

Current video monitoring technologies face challenges in achieving continuous monitoring of a target person, especially when they enter buildings, as cameras are often obstructed by objects and lose sight of the target due to limitations in camera placement and signal range.

Innovation Solution

A monitoring method utilizing WiFi detectors placed in a triangular configuration with an image capturing module, where the WiFi detectors can determine the MAC address of a target person's WiFi terminal by calculating distance ratios based on signal strength, allowing for continuous tracking even when the target enters a building.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If video monitoring technology using cameras is used to monitor target persons, then monitoring can be achieved in open areas, but cameras are obstructed by objects such as trees and advertisement boards and cannot acquire images when target persons enter buildings, resulting in monitoring failure

Engineering Contradiction:
Improvemonitoring continuityVSAvoidenvironmental coverage
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent combines video monitoring technology with WiFi positioning technology into an integrated monitoring system. The server receives both video data from cameras and WiFi signal data from terminals, fuses these data sources, and performs comprehensive analysis to achieve continuous monitoring across different environments including both outdoor and indoor areas.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces WiFi signal detection as an intermediary mechanism to bridge the monitoring gap when cameras fail. WiFi detectors capture signal strength data from terminals, and the server uses this intermediary data source to maintain monitoring capability when direct visual monitoring via cameras is blocked or unavailable.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Area of stationary object

If cameras are placed at main traffic accesses and entrances to monitor target persons, then monitoring coverage is established, but cameras are prone to obstruction and unable to track targets inside buildings

Engineering Contradiction:
Improvemonitoring coverage areaVSAvoidmonitoring effectiveness
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The monitoring system is designed with multi-functionality to handle diverse monitoring scenarios. It can switch between video-based monitoring in outdoor areas and WiFi-based monitoring in indoor areas, providing universal monitoring capability across different environments and conditions rather than being limited to a single method.

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

Solution Approach 2:

The system changes monitoring parameters dynamically based on environment. It transitions from optical parameter-based monitoring (video) to electromagnetic signal parameter-based monitoring (WiFi signal strength), adapting the monitoring approach according to whether the target is in outdoor or indoor areas.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If only video monitoring is used, then simple camera placement can monitor outdoor areas, but monitoring fails when targets enter buildings due to camera limitations

Engineering Contradiction:
Improvesystem structureVSAvoidcontinuous monitoring capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The monitoring system is segmented into multiple independent components: video detection modules for outdoor monitoring, WiFi detection modules for indoor monitoring, and a fusion server that integrates data from both segments. This segmentation allows each component to specialize in specific environments while maintaining overall system reliability through coordinated operation.

Inventive Principle:
Principle #1Segmentation

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

Enables continuous monitoring of a target person by determining their location and trajectory using WiFi signal strength and MAC address, overcoming the limitations of camera obstructions and indoor signal loss.

Implementation Method 1

obtaining signal strength of WiFi signals of a plurality of terminals detected by the at least one WiFi detector at the appearance moment

Methodology Applied
Scientific EffectWiFi signal propagation: Electromagnetic Induction

Data Source

PatentEP3297275B1Method, server, system, and image capturing device for surveillance
Publication Date: 2020.09.30 HANGZHOU HIKVISION DIGITAL TECHNOLOGY CO LTD
  • EP3297275B1 patent drawingFigure 1
  • EP3297275B1 patent drawingFigure 2
  • EP3297275B1 patent drawingFigure 3

AI summary

Embodiments of the application provide a monitoring method, server and system and an image acquisition device capable of obtaining a first distance ratio of the horizontal distances from three WiFi detectors to a target person. The application is also capable of obtaining a second distance ratio of the horizontal distances from the three WiFi detectors to a WiFi terminal based on the signal strength of WiFi signals. The application determines the MAC address of the WiFi terminal of the target person by matching the second distance ratios of various WiFi terminals with the first distance ratio, and monitors the target person according to the MAC address. Thus, the application achieves continuous monitoring of the target person.