Room Entry Detection Using Door State and Person Sensors

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Solution Overview

Problem

Existing techniques for room entry and exit detection are inaccurate when using a small number of sensors, often requiring multiple cameras or sensors to mitigate errors, leading to increased costs and power consumption.

Innovation Solution

A system comprising a person detection sensor, an open and close detection sensor, and corresponding recorders to accurately detect entries and exits by recording state changes when the door transitions between open and closed states, using a combination of pyroelectric infrared sensors and acceleration sensors to minimize the number of sensors required.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple television cameras and dedicated processors are installed to improve detection accuracy, then detection accuracy is improved, but device complexity and cost increase

Engineering Contradiction:

Improvedetection accuracyVSAvoidnumber of sensors

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the functions of multiple sensors into a single integrated sensor unit that simultaneously detects door open/close state and person presence. This merging approach achieves accurate entry/exit detection without requiring multiple separate cameras and processors, thereby improving detection accuracy while reducing device complexity.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If more person-detection sensors are installed to avoid false detection, then detection reliability is improved, but power consumption and maintenance cost increase

Engineering Contradiction:

Improvedetection reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic action by only activating the person detection function when the door state changes (opens or closes). The system periodically checks for person presence at these specific moments rather than continuously monitoring, which maintains high detection reliability while significantly reducing power consumption compared to continuous monitoring with multiple sensors.

Inventive Principle:

Principle #19Periodic action

3Reliability

If auxiliary sensors are added to prevent false detection, then detection reliability is improved, but device complexity and installation cost increase

Engineering Contradiction:

Improvedetection reliabilityVSAvoidnumber of sensors

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a single sensor unit that performs multiple functions: detecting door open/close state, detecting person presence, and determining entry/exit direction. This multi-functional approach eliminates the need for separate auxiliary sensors, maintaining high detection reliability while reducing the total number of sensors and simplifying installation.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Measurement precision

If multiple sensors are used to improve detection accuracy, then detection accuracy is improved, but installation and maintenance cost increase

Engineering Contradiction:

Improvedetection accuracyVSAvoidinstallation cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges multiple sensing functions into a single integrated sensor unit, which simplifies installation by requiring only one sensor installation location rather than multiple separate sensor installations. This approach maintains high detection accuracy through intelligent processing of combined sensor data while reducing installation complexity and associated costs.

Inventive Principle:

Principle #5Merging (Combining)

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 allows for accurate detection of room entries and exits with a reduced number of sensors, preventing false detections and lowering installation, maintenance, and power consumption costs.

Implementation Method 1

using a combination of pyroelectric infrared sensors and acceleration sensors

Methodology Applied

Scientific EffectPyroelectric effect: Pyroelectric Effect

Implementation Method 2

using a combination of pyroelectric infrared sensors and acceleration sensors

Methodology Applied

Scientific EffectAcceleration detection: Accelerometer

Data Source

PatentUS9606261B2Room entry/exit detection apparatus, room entry/exit detection method, and computer-readable recording medium having program recorded thereon

Publication Date: 2017.03.28 NEC SOLUTION INNOVATORS LTD

AI summary

A person detector detects a person in an area facing one door surface. An open/close detector detects whether the door is in an open or closed state. When a detected state of the door switches from a closed state to an open state, an open-state person detection information recorder records whether the person detector is detecting a person or not. When the state of the door detected by the open and close detection sensor switches from the open state to the closed state, a closed-state person detection information recorder records whether the person detector is detecting a person or not. A room entry and exit detector detects that there occurs an entry into the room and there occurs an exit out of the room on the basis of a content recorded by the open-state person detection information recorder and the closed-state person detection information recorder.