Embedded Downlight Radar for Human Traffic Direction Counting

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Solution Overview

Problem

Conventional systems for monitoring human traffic in buildings, such as infrared and camera-based systems, lack the ability to accurately determine the direction of human movement and count individuals entering or exiting, which is essential for various applications including safety, marketing, and resource management.

Innovation Solution

A downlight system integrated with a monostatic millimeter-wave radar that transmits and receives radar signals to detect human presence and determine movement direction, using range information to differentiate between individuals entering and exiting, and a wireless module to transmit log data to a server for further analysis and control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional infrared or camera-based systems are used for monitoring human traffic, then the system can detect human presence, but it cannot accurately determine the direction of human movement or count individuals entering or exiting

Engineering Contradiction:
Improvedirection detection accuracyVSAvoidmovement direction information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent replaces conventional infrared or camera-based detection systems with a millimeter-wave radar system. The radar uses electromagnetic wave transmission and reception to detect human presence, movement direction, and count individuals. By analyzing the phase difference and time difference of reflected waves received by multiple antennas, the system accurately determines movement direction without relying on optical or thermal fields, thus resolving the limitation of conventional systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If additional sensors or complex image processing systems are deployed to determine movement direction, then direction detection capability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvemovement direction detectionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the millimeter-wave radar system multi-functional by enabling it to simultaneously perform human presence detection, movement direction determination, and individual counting using the same hardware components. The radar transmits electromagnetic waves and processes reflected signals to extract multiple types of information without requiring additional sensors or complex image processing systems, thus reducing device complexity while maintaining high measurement precision.

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

Solution Approach 2:

The patent combines the functions of detecting human presence, determining movement direction, and counting individuals into a single integrated radar system. By merging these functions into one system that processes radar signals, the patent eliminates the need for separate sensors or complex image processing pipelines, thereby reducing overall system complexity while achieving accurate direction detection.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If multiple antennas and complex signal processing are used to determine movement direction, then detection accuracy is improved, but the system becomes more complex

Engineering Contradiction:
Improvehuman detection accuracyVSAvoidradar system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex image processing or multi-sensor fusion systems with a millimeter-wave radar system that uses electromagnetic wave reflection principles. The radar transmits waves and analyzes the reflected signals to detect human presence, movement, and direction. This substitution simplifies the system architecture while maintaining high detection accuracy through physics-based signal processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses feedback from the reflected radar waves to continuously update information about human presence, movement direction, and counting. By analyzing the phase difference and time difference of reflected waves received by multiple antennas, the system dynamically determines movement direction and updates detection results in real-time, achieving high accuracy without requiring overly complex processing systems.

Inventive Principle:
Principle #23Feedback

4Use of energy by moving object

If conventional light bulbs are used, then lighting function is provided, but energy efficiency is low and heat generation is high

Engineering Contradiction:
Improvelighting energy efficiencyVSAvoidheat loss
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent changes the fundamental operating parameters of the lighting system by replacing conventional incandescent or fluorescent bulbs with LED technology. LEDs operate at lower temperatures and convert electrical energy more efficiently into light, significantly reducing energy waste as heat. This parameter change in the lighting source achieves both improved energy efficiency and reduced heat generation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes conventional thermal radiation-based lighting (incandescent bulbs) with electroluminescence-based LED lighting. This substitution fundamentally changes the energy conversion mechanism from heating a filament to direct electrical-to-optical conversion in semiconductor materials, thereby improving energy efficiency and reducing heat loss in the lighting system.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The system effectively monitors human traffic by accurately determining movement direction and counting individuals, enabling dynamic control of lighting and other building systems based on occupancy levels, improving efficiency and safety without the need for additional sensors or complex image processing.

Implementation Method 1

a monostatic millimeter-wave radar disposed in the housing. The millimeter-wave radar includes: An RF circuit configured to transmit and receive radar signals and an antenna disposed in the housing. The RF circuit is configured to receive, via the antenna, an echo signal of a radar signal transmitted by the RF circuit.

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

The RF circuit is configured to receive, via the antenna, an echo signal of a radar signal transmitted by the RF circuit.

Methodology Applied
Scientific EffectEcho: Echo

Data Source

PatentEP3624568B1Embedded downlight and radar system
Publication Date: 2024.01.10 INFINEON TECHNOLOGIES AG
  • EP3624568B1 patent drawingFigure 1~2
  • EP3624568B1 patent drawingFigure 3~6D
  • EP3624568B1 patent drawingFigure 4~5A

AI summary

In an embodiment, a downlight includes: a plurality of light emitting diodes (LEDs) disposed in a housing of the downlight, and a millimeter-wave radar. The millimeter-wave radar includes: an antenna disposed in the housing, a controller configured to: detect a presence of a human in a field-of-view of the millimeter-wave radar, determine a direction of movement of the detected human, and produce log data based on the direction of movement of the detected human, and a wireless module configured to transmit the log data to a wireless server.