Motion Detection Apparatus and Motion Detecting Method

• US 20090006028A1
• Filed: 11/01/2005
• Published: 01/01/2009
• Est. Priority Date: 11/05/2004
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Kawahara, Kohji, Sugawara, Takashi, Chotoku, Yuji
• Granted Patent: US 7,813,892 B2
• Time in Patent Office: Days
• US Class Current: 702/141
• CPC Class Codes: G01H 1/06 Frequency
• CPC Class Codes: G01H 1/08 Amplitude
• CPC Class Codes: G06F 21/88 Detecting or preventing theft or loss
• CPC Class Codes: G08B 13/1436 with motion detection

Abstract

A motion detection apparatus includes an acceleration sensor which detects acceleration generated by motion of an electronic device; a motion detecting section including a statistical processing section which calculates the average value of data provided from the acceleration sensor, calculates the difference between the average value and the last value of the data obtained, and calculates a pseudo-variance value of the data from the calculated difference; a threshold comparing section which compares the pseudo-variance value calculated by the motion detecting section with a motion threshold to generate a signal value in response to determination that the pseudo-variance value has exceeded the motion threshold; a first buffer memory which sequentially stores signal values generated by the threshold comparing section at predetermined time intervals; and a signal generating section which includes means for adding up values in the first buffer memory, thereby appropriately associating acceleration with motion.

Claims

1. A motion detection apparatus for detecting motion of an electronic device, comprising:

an acceleration sensor which detects acceleration generated by motion of the electronic device;

a motion detecting section including a statistical processing section which calculates the average value of data provided from the acceleration sensor, calculates the difference between the average value and the last value of the data obtained, and calculates from the difference a pseudo-variance value of the data;

a comparing section which compares the pseudo-variance value calculated by the motion detecting section with a motion threshold and generates a signal value in response to determination that the pseudo-variance value exceeds the motion threshold; and

a signal generating section including means for sequentially adding up the signal values generated by the comparing section at predetermined time intervals.

2. The motion detection apparatus according to claim 1, wherein the statistical processing section comprises:

a short-time motion deviation generating section which generates a plurality of the differences from the average value of the data at predetermined time intervals, calculates the sum of squares of the plurality of differences generated to generate a short-time motion deviation, and writes the short-time motion deviation in a memory; and

a pseudo-variance value calculating section which adding up the short-time motion deviation values written in the memory to obtain a pseudo-variance value.

3. The motion detection apparatus according to claim 1, wherein the signal generating section comprises a threshold comparing section which compares the accumulated value obtained by adding up the signal values with a plurality of control thresholds, and a control signal generating section which generates different control signals in response to the accumulated value exceeding the plurality of control thresholds.

4. The motion detection apparatus according to claim 1, wherein the signal value is a binary signal value and the signal generating section comprises a first buffer memory for storing the signal value.

5. The motion detection apparatus according to claim 2, wherein the short-time motion deviation generating section comprises a second buffer memory in which the short-time motion deviation is written.

6. The motion detection apparatus according to claim 1, wherein the motion detection apparatus is an antitheft module of the electric apparatus.

16. An electronic device comprising the motion detection apparatus according to claim 1 as an antitheft module.

7. A method for detecting motion of an electronic device, comprising the steps of:

obtaining data from an acceleration sensor generated by motion of the electronic device, sending the data to a motion detecting section to cause the motion detecting section to calculate the average value of the data, calculate the difference between the average value and the last value of the data obtained to generate a short-time motion deviation, and calculate a pseudo-variance value of the data from the short-time motion deviation;

sending the calculated pseudo-variance value to a threshold comparing section to cause the threshold comparing section to compare the pseudo-variance value with a motion threshold and to generate a signal value in response to determination that the pseudo-variance value exceeds the motion threshold; and

causing the generated signal values to be sequentially added up at predetermined time intervals to generate an accumulated value.

8. The motion detecting method according to claim 7, comprising the steps of:

causing the motion detecting section to generate a plurality of differences between the data and the average value at predetermined time intervals and to calculate the sum of squares of the plurality of generated differences to generate a short-time motion deviation; and

writing a plurality of the short-time motion deviation in a memory and adding up the plurality of short-time motion deviation stored in the memory to obtain a pseudo-variance value.

9. The motion detecting method according to claim 8, comprising the steps of:

adding up the signal values to generate an accumulated value and comparing the generated accumulated value with a plurality of control thresholds for generating a control signal; and

generating different control signals in response to the accumulated value exceeding the plurality of control thresholds.

10. The motion detecting method according to claim 7, wherein the step of generating the accumulated value comprises the steps of:

storing the signal values in memory in a time sequence; and

reading and adding up the signal values stored in the memory in a time sequence.

11. The motion detecting method according to claim 7, wherein it is a method for protecting the electronic device from theft.

12. A computer-executable program product causing a computer to execute a method for detecting motion of an electronic device, the program product causing the computer to perform the steps of:

obtaining data from an acceleration sensor generated by motion of the electronic device, sending the data to a motion detecting section to cause the motion detecting section to calculate the average value of the data, calculate the difference between the average value and the last value of the data obtained to generate a short-time motion deviation, and calculate a pseudo-variance value of the data from the short-time motion deviation;

sending the calculated pseudo-variance value to a threshold comparing section to cause the threshold comparing section to compare the pseudo-variance value with a motion threshold and to generate a signal value in response to determination that the pseudo-variance value exceeds the motion threshold; and

causing the generated signal values to be sequentially added up at predetermined time intervals to generate an accumulated value.

13. The program product according to claim 12, causing the computer to perform the steps of:

causing the motion detecting section to generate a plurality of differences between the data and the average value at predetermined time intervals and to calculate the sum of squares of the plurality of generated differences to generate a short-time motion deviation; and

writing a plurality of the short-time motion deviation in a memory and adding up the plurality of short-time motion deviation stored in the memory to obtain a pseudo-variance value.

14. A processing module which performs processing for detecting motion of an electronic device, comprising:

a functional section which obtains data from an acceleration sensor generated by motion of the electronic device, sends the data to a motion detecting section to cause the motion detecting section to calculate the average value of the data, calculate the difference between the average value and the last value of the data obtained to generate a short-time motion deviation, and calculate a pseudo-variance value of the data from the short-time motion deviation;

a processing section which sends the calculated pseudo-variance value to a threshold comparing section to cause the threshold comparing section to compare the pseudo-variance value with a motion threshold and to generate a signal value in response to determination that the pseudo-variance value exceeds the motion threshold; and

a processing section which causes the generated signal values to be sequentially added up at predetermined time intervals to generate an accumulated value.

15. The processing module according to claim 14, comprising:

a processing section which causes the motion detecting section to generate a plurality of differences between the data and the average value at predetermined time intervals and to calculate the sum of squares of the plurality of generated differences to generate a short-time motion deviation; and

a processing section which writes a plurality of the short-time motion deviation in a memory and adds up the plurality of short-time motion deviation stored in the memory to cause a pseudo-variance value to be calculated.