Method and apparatus for reliable detection of opening and closing events

Patent metadata

Field	Value
Publication number	US-10006929-B2
Application number	US-201515520614-A
Country	US
Kind code	B2
Filing date	Oct 14, 2015
Priority date	Oct 28, 2014
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

A methods is provided for reliable and accurate detection of opening or closing of doors or drawers using output signals generated by a sensor, the output signals directly or indirectly representative of the acceleration of the sensor over time. Areas under a curve for acceleration, or representations thereof, are determined and occurrence of movement events identified through comparison of calculated areas with certain thresholds. Areas are considered which span between zero crossing points of the acceleration curve, such that all elements of the corresponding sum are of the same sign, and consequent area signals have maximal amplitude. Pairs of substantially equal and opposite area signals may be sought, occurring within a given time separation, these characteristic of an opening or closing motion, consisting of a first acceleration in a first direction followed by a second in an opposing direction. Apparatus for the reliable detection of opening or closing events is also provided.

First claim

The invention claimed is:

1. A method for detecting opening or closing events using a movement sensor that is capable of providing a sensor signal which is dependent on the movement of the movement sensor, the method comprising the steps of:
a) obtaining the sensor signal over time;
b) determining crossing time points at which the sensor signal indicates acceleration of the movement sensor crossing zero;
c) deriving area signals representing an area under a curve of the acceleration of the movement sensor versus time, with a respective area signal derived between successive crossing time points; and
d) detecting opening or closing events based on a comparison of the area signals with one or more thresholds.

2. The method as claimed in claim 1 , wherein the detecting of opening or closing events comprises identifying area signals which exceed the one or more thresholds and which relate to positive acceleration, and determining for each whether there exists a subsequent area signal exceeding the one or more thresholds and relating to negative acceleration.

3. The method as claimed in claim 1 , wherein obtaining the sensor signal comprises first obtaining a sensor output, and subsequently processing said output to extract a single directional component, the direction corresponding to a direction of motion of the sensor.

4. The method as claimed in claim 3 , wherein obtaining the sensor signal comprises:
obtaining a sensor output vector;
defining a second vector representing a direction of motion of the sensor; and
subsequently performing a scalar product operation upon said sensor output vector with respect to the second vector.

5. The method as claimed in claim 4 , wherein defining the second vector representing a direction of motion of the sensor comprises performing a process of principal component analysis upon one or more components of the obtained sensor output vector.

6. The method as claimed in claim 5 , wherein obtaining the sensor output vector comprises first obtaining an initial, three dimensional, output vector and subsequently processing said initial output vector to extract components in the plane perpendicular to the direction of gravity.

7. The method as claimed in claim 6 , further comprising determining the direction of gravity relative to the movement sensor through analysis of one or more sensor outputs.

8. A method of detecting opening or closing events using a movement sensor that is capable of providing a sensor signal which is dependent on the movement of the movement sensor, the method comprising:
obtaining the sensor signal over time;
detecting by analysis of the sensor signal the occurrence of any rotational opening or closing events about a horizontal axis; and
in the case that no occurrence of an opening or closing event about a horizontal axis is detected, subsequently detecting opening or closing events in accordance with the method of claim 1 .

9. The method as claimed in claim 8 , wherein detecting the occurrence of rotational opening or closing events about a horizontal axis comprises:
analyzing the sensor signal to determine a direction of gravity over time with respect to the movement sensor;
detecting changes over time in the determined direction of gravity; and
detecting the occurrence of rotational opening or closing events based on a comparison of the said detected changes with one or more thresholds.

10. The method as claimed in claim 9 , further comprising identifying changes in the directionality of consecutively detected opening or closing events, by performing one or more vector product operations between the determined direction of gravity vectors for each detected opening or closing event, and identifying changes in directionality by comparing the sign of the results of said one or more vector product operations for consecutively detected events.

11. A non-transitory computer program product stored on a computer-readable medium and containing program code instructions which when executed by a microprocessor causes the microprocessor to implement the method as claimed in claim 1 .

12. The method as claimed in claim 1 , wherein obtaining a signal over time comprises using an accelerometer.

13. An apparatus for the detection of opening or closing events, comprising:
a movement sensor adapted to be mounted to a moveable object;
a processing element for analyzing one or more sensor outputs and detecting from said analysis the occurrence of opening or closing events, wherein said processing element is adapted to:
obtain a signal over time which is dependent on the movement of the sensor;
determine crossing time points at which the sensor signal indicates acceleration of the movement sensor crossing zero;
derive area signals representing the area under a curve of the acceleration of the movement sensor versus time, with a respective area signal derived between successive crossing time points; and
detect opening or closing events based on a comparison of the area signals with one or more thresholds.

14. The apparatus for the detection of opening or closing events as claimed in claim 13 , wherein the processing element is adapted to assume a primary direction of movement of the movement sensor aligned with a known axis of the movement sensor.

15. The apparatus for the detection of opening or closing events as claimed in claim 13 , wherein the sensor is an accelerometer, and wherein the opening or closing events are for example characterized by a first acceleration in a first direction, followed by a second acceleration in a second, opposing, direction.

Assignees

• Koninklijke Philips Nv

Inventors

• Ten Kate Warner Rudolph Theophile

Classifications

• A47B88/00

  Drawers for tables, cabinets or like furniture; Guides for drawers (A47B63/02 takes precedence; drawers coupled to doors A47B96/16) · CPC title

• E05B2047/0067

  Monitoring · CPC title

• G08B13/08

  by opening, e.g. of door, of window, of drawer, of shutter, of curtain, of blind · CPC title

• G01P7/00 Primary

  Measuring speed by integrating acceleration (measuring travelled distance by double integration of acceleration G01C21/16) · CPC title

• E06B7/28

  Other arrangements on doors or windows, e.g. door-plates, windows adapted to carry plants, hooks for window cleaners {(edge protecting devices for door leaves E06B3/88; special glazing; emergency glazing; double glazing E06B3/66)} · CPC title