Object state detection apparatus and method

• US 8,508,219 B2
• Filed: 04/28/2009
• Issued: 08/13/2013
• Est. Priority Date: 04/30/2008
• Status: Active Grant

• Current Assignee: National Institute of Advanced Industrial Science and Technology (Government of Japan)
• Original Assignee: National Institute of Advanced Industrial Science and Technology (Government of Japan)
• Inventors: Shimizu, Mitsuaki, Kaji, Ryosaku, Hirota, Kiyomi
• Primary Examiner(s): ISLA RODAS, RICHARD
• Application Number:
  US12/431,300
• Publication Number:
  US 20100019759A1
• Time in Patent Office: 1,568 Days
• Field of Search: 324/144
• US Class Current: 324/207.22
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: G01V 15/00 Tags attached to, or associated with, an object, in order to enable detection of the object record carriers for use with machines having a detectable tag or marker G06K19/00

Abstract

There is provided an apparatus and method for identifying and measuring the electric field strength which occurs from each of RFID tags arranged in a detection target space by a receiver to grasp the state of an object. The apparatus is provided with m (m>=1) electromagnetic field generation means provided near a space, the space being occupied by the object when the object is in a particular state; n (n>=1) electric field strength measurement means for identifying and measuring electric field strength which occurs from each of the m electromagnetic field generation means; characteristic extraction means for calculating characteristics from m×n time-series data of the electric field strength; and state identification means for identifying, by statistical processing, a state from the characteristics and characteristic data in each state for learning.

Claims

1. An apparatus for detecting a state of an object, comprising:

m (m>

=1) electromagnetic field generators provided near a space, the space being occupied by the object when the object is in a particular state;

n (n>

=1) electric field strength measurement devices for identifying and measuring electric field strength which occurs from each of the m electromagnetic field generators; and

at least one processor configured to calculate characteristics from time-series data of m×

n electric field strength and to identify, by statistical processing, the state of the object from the characteristics and characteristic data collected in each of a plurality of still states of the object, wherein the at least one processor is configured to learn an upper-limit value and a lower-limit value of the electric field strength for each time-series data based on the characteristic data of each still state which has been collected, and wherein the at least one processor is configured to identify the state by the fact that input characteristic data is between the upper-limit value and the lower-limit value of the electric field strength or to identify the state by the fact that input characteristic data is not between the upper-limit value and the lower-limit value of the electric field strength, the input characteristic data being time-series data comprising the amount of fluctuation of the time series data of the m×

n electric field strength for a predetermined period.

2. The object state detection apparatus according to claim 1, wherein each of the electromagnetic field generators has an antenna structure for controlling spatial distribution of accumulated fields.

3. The object state detection apparatus according to claim 1, wherein an efficiency of radiation of an electromagnetic field into free space by the electromagnetic field generators changes when an object exists nearby.

4. The object state detection apparatus according to claim 1, wherein the n electric field strength measurement devices are arranged so that the states of the electromagnetic fields which occur from the electromagnetic field generators changing due to existence of the object can be measured separately from one another.

5. The object state detection apparatus according to claim 1, wherein the at least one processor is configured to convert m×

n electric field strength values at the time when the space is in a still state into vector data with m×

n elements.

6. The object state detection apparatus according to claim 1, wherein the apparatus executes alarm processing in accordance with the state identification by the at least one processor.

7. The object state detection apparatus according to claim 1, wherein the apparatus performs processing of photographing data of the space in accordance with the state identification by the at least one processor.

8. A method for detecting a state of an object, the method comprising acts of:

providing m (m>

=1) transmitters near a space, the space being occupied by the object when the object is in a particular state;

identifying and measuring electric field strength which occurs from each of the m transmitters by n (n>

=1) receivers;

calculating characteristics from time-series data of m×

n electric field strength; and

identifying, by statistical processing, the state of the object from the characteristics and characteristic data collected in each of a plurality of still states of the object, wherein an upper-limit value and a lower-limit value of the electric field strength is learned for each time-series data based on characteristic data of each still state which has been collected, and wherein the state is identified by the fact that input characteristic data is between the upper-limit value and the lower-limit value of the electric field strength or the state is identified by the fact that the input characteristic data is not between the upper-limit value and the lower-limit value of the electric field strength, the input characteristic data being time-series data comprising the amount of fluctuation of the time series data of the m×

n electric field strength for a predetermined period.

9. The object state detection method according to claim 8, wherein each of the transmitters has an antenna structure for controlling spatial distribution of accumulated fields.

10. The object state detection method according to claim 8, wherein an efficiency of radiation of an electromagnetic field into free space by each of the transmitters changes when the object exists nearby.

11. The object state detection method according to claim 8, wherein the n receivers are arranged so that the states of electromagnetic fields which occur from the transmitters changing due to existence of the object can be measured separately from one another.

12. The object state detection method according to claim 8, wherein the act of calculating characteristics includes converting m×

n electric field strength values at the time when the space is in a still state into vector data with m×

n elements.

13. The object state detection method according to claim 8, wherein alarm processing is executed in accordance with identifying the state of the object.

14. The object state detection method according to claim 8, wherein processing of photographing data of the space is performed in accordance with identifying the state of the object.