Ultrasonic Passenger Detection with Echo Integration

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Solution Overview

Problem

Existing ultrasonic detection methods for transit vehicle doorways fail to accurately distinguish between echoes from permanent equipment and passengers or objects, leading to 'dead zones' where responses are ignored, and cannot effectively discriminate between on-axis and off-axis targets.

Innovation Solution

The method involves directing ultrasound transmitters/receivers at the door area, emitting pulses, recording and integrating echo intensities, and comparing them to standard values, considering both time and amplitude, to detect passengers by identifying deviations from stored standards, with multiple sensors and adjustable response periods to account for environmental changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ultrasonic detection uses memorized signature tables with tolerances to represent dead zones, then permanent equipment echoes are filtered out, but passenger detection accuracy deteriorates because passenger echoes occurring within tolerances are ignored

Engineering Contradiction:

Improvepermanent equipment echo filteringVSAvoidpassenger detection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the detection parameters from simple time-based signature matching to integrated amplitude-time analysis. By integrating echo amplitude over time and comparing against stored standards, the system can distinguish passengers from permanent equipment even when their echo times overlap within tolerances, resolving the contradiction between filtering permanent equipment and detecting passengers.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical signature table matching approach with an electronic integration and comparison system. Instead of using fixed tolerances that create dead zones, the system integrates echo amplitudes over time and compares against stored standards, enabling more precise discrimination between passengers and permanent equipment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Area of stationary object

If ultrasonic pulses are directed at a volume of space, then the detection coverage is improved, but the discrimination between on-axis and off-axis targets deteriorates without additional processing

Engineering Contradiction:

Improvedetection coverage areaVSAvoidtarget position discrimination

Core Design Contradiction:

Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent adds the amplitude integration dimension to the existing time-based detection. By integrating echo amplitude over the response period and comparing against stored standards, the system can discriminate between on-axis and off-axis targets in addition to detecting their presence, resolving the contradiction between coverage area and position discrimination.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Loss of information

If the response period is extended to capture all echoes, then complete echo information is obtained, but discrimination between floor echoes and passenger echoes deteriorates

Engineering Contradiction:

Improveecho information completenessVSAvoidfloor vs passenger echo discrimination

Core Design Contradiction:

Loss of informationVSMeasurement precision

Solution Approach 1:

The patent uses continuous integration of echo amplitude over the entire response period rather than sampling at discrete points. This continuous integration captures all echo information while the comparison against stored standards maintains the ability to discriminate between floor echoes and passenger echoes, resolving the contradiction between information completeness and discrimination precision.

Inventive Principle:

Principle #20Continuity of useful action

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 enhances the accuracy of passenger detection by integrating echo signal amplitude and time, reducing 'dead zones' and improving discrimination between permanent equipment and moving targets, allowing for reliable door operation.

Implementation Method 1

emitting an ultrasound pulse via the transmitter/receiver into the volume of space... recording the ultrasound echoes from objects in the volume of space

Methodology Applied

Scientific EffectUltrasonic echo: Echo

Implementation Method 2

recording the ultrasound echoes from objects in the volume of space

Methodology Applied

Scientific EffectSound reflection: Reflection

Data Source

PatentUS8791839B2Ultrasonic passenger detection

Publication Date: 2014.07.29 WABTEC HLDG CORP

AI summary

A method and apparatus of recognizing the presence of a passenger in front of a door of a transit vehicle comprises directing an ultrasound transmitter/receiver at a volume of space adjacent the door, emitting an ultrasound pulse into the empty volume, recording and integrating intensity of the echoes and storing the integrated value as a standard value, repeatedly emitting an ultrasound pulse into the volume, and comparing the integrated values to the standard value.