METHOD, APPARATUS AND ARTICLE FOR DETECTION OF TRANSPONDER TAGGED OBJECTS, FOR EXAMPLE DURING SURGERY

• US 20150272688A1
• Filed: 07/09/2014
• Published: 10/01/2015
• Est. Priority Date: 03/31/2014
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: RF Surgical Systems, Incorporated (Medtronic Plc)
• Inventors: Blair, William A., Poirier, David A., Crump, Curtis
• Granted Patent: US 9,514,341 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2505/05 Surgical care
• CPC Class Codes: A61B 5/061 Determining position of a probe within the body employing means separate from the probe, e.g. sensing internal probe position employing impedance electrodes on the surface of the body A61B1/00158 takes precedence
• CPC Class Codes: A61B 90/90 Identification means for patients or instruments, e.g. tags
• CPC Class Codes: A61B 90/98 using electromagnetic means, e.g. transponders
• 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
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: G06K 7/10366 the interrogation device being adapted for miscellaneous applications
• CPC Class Codes: G06K 7/10386 the interrogation device being of the portable or hand-handheld type, e.g. incorporated in ubiquitous hand-held devices such as PDA or mobile phone, or in the form of a portable dedicated RFID reader

Abstract

The presence or absence of objects is determined by interrogating or exciting transponders coupled to the objects using pulsed wide band frequency signals. Interrogation is broken down into a number of subsample scan cycles each having interrogation cycles a start time forward in time by a fraction of a period of an expected transponder response signal. Ambient or background noise is evaluated and a threshold adjusted based on the level of noise. Adjustment may be based on multiple noise measurements or samples. Noise detection may be limited, with emphasis placed on interrogation to increase the signal to noise ratio. Matched filtering may be employed. Presence/absence determination may take into account frequency and/or Q value to limit false detections. Appropriate acts may be taken if detected noise is out of defined limits of operation, for example shutting down interrogation and/or providing an appropriate indication.

Claims

1. A method of operating a transponder detection device that includes at least one processor, at least one nontransitory processor-readable medium communicatively coupled to the at least one processor and which stores at least one of instructions or data executable by the at least one processor, the method comprising:

during each of a first plurality of successive interrogation cycles,

emitting a periodic electromagnetic interrogation signal during a transmit portion of the interrogation cycle;

receiving electromagnetic signals during a receive response portion of the interrogation cycle that follows the transmit portion of the interrogation cycle; and

waiting a first delay period before a start of each of the successive interrogation cycles of the first plurality of interrogation cycles, the first delay period for the first plurality of interrogation cycles equal to a first fraction of a nominal tag response signal period;

during each of a second plurality of successive interrogation cycles,

emitting a periodic electromagnetic interrogation signal during a transmit portion of the interrogation cycle;

receiving electromagnetic signals during a receive response portion of the interrogation cycle that follows the transmit portion of the interrogation cycle; and

waiting a second delay period before a start of each of the successive interrogation cycles in the second plurality of interrogation cycles, the second delay period for the second plurality of interrogation cycles equal to a second fraction of the nominal tag response signal period, the second fraction of the nominal tag response signal period different from the first fraction of the nominal tag response signal period.

2-24. -24. (canceled)

25. A method of operating a transponder detection device that includes at least one processor, at least one nontransitory processor-readable medium communicatively coupled to the at least one processor and which stores at least one of instructions or data executable by the at least one processor, the method comprising:

obtaining a number of subsamples, each of the subsamples associated with a respective delay period equal to a respective fraction of a nominal tag response signal period, the respective fractions different from one another, each of the number of subsamples obtained by;

during each of a plurality of successive interrogation cycles associated with each of the number of subsamples,

emitting a periodic electromagnetic interrogation signal during a transmit portion of the interrogation cycle;

receiving electromagnetic signals during a receive response portion of the interrogation cycle that follows the transmit portion of the interrogation cycle; and

waiting the delay period of the one of the number of subsamples to which the interrogation cycle is associated before a start of each of the successive interrogation cycles of the plurality of interrogation cycles.

26. The method of claim 25 wherein waiting a delay period before a start of each of the successive interrogation cycles of the plurality of interrogation cycles comprises waiting a delay period before a start of each of the successive interrogation cycles of the plurality of interrogation cycles, the delay period for each of the number of subsamples between zero seconds and the nominal tag response signal period.

27. The method of claim 25 wherein waiting a delay period before a start of each of the successive interrogation cycles of the plurality of interrogation cycles comprises waiting a delay period before a start of each of the successive interrogation cycles of the plurality of interrogation cycles, the delay period for at least one of the number of subsamples being a duration between the nominal tag response signal period and twice the nominal tag response signal period.

28. The method of claim 25 wherein waiting a delay period before a start of each of the successive interrogation cycles of the plurality of interrogation cycles comprises waiting a delay period before a start of each of the successive interrogation cycles of the plurality of interrogation cycles and, for each successive pair of subsamples, the delay period associated with a first successive one of the pairs of subsamples is less than the delay period associated with a next successive one of the pairs of subsamples.

29. The method of claim 25 wherein waiting a delay period before a start of each of the successive interrogation cycles of the plurality of interrogation cycles comprises waiting a delay period before a start of each of the successive interrogation cycles of the plurality of interrogation cycles and, for each successive pair of subsamples, the delay period associated with a first successive one of the pairs of subsamples is less than the delay period associated with a next successive one of the pairs of subsamples by a duration approximately equal to the nominal tag response signal period divided by the number of subsamples.

30. The method of claim 25 wherein waiting a delay period before a start of each of the successive interrogation cycles of the plurality of interrogation cycles comprises waiting a delay period before a start of each of the successive interrogation cycles of the plurality of interrogation cycles, and the delay period associated with each subsample differs from the delay period for the other subsamples by less than the nominal tag response signal period.

31. The method of claim 25 wherein waiting a delay period before a start of each of the successive interrogation cycles of the plurality of interrogation cycles comprises waiting a delay period before a start of each of the successive interrogation cycles of the plurality of interrogation cycles, and the delay period associated with each subsample is approximately an integer multiple of the nominal tag response signal period divided by the number of subsamples.

32. The method of claim 25, further comprising:

during each of the plurality of interrogation cycles, before the receive response portion of the interrogation cycle, waiting a fixed recovery time after the transmit portion of the interrogation cycle, the fixed recovery time having a duration determined to provide synchronization between the transmit portion and the receive response portion of each interrogation cycle.

33. The method of claim 25 wherein the transponder detection device includes a plurality of antennas, the method further comprising:

obtaining a number of subsamples for each of the plurality of antennas.

34. The method of claim 25, further comprising:

determining the presence or absence of a transponder based at least in part on a number of measurements of the electromagnetic signals received during the plurality of interrogation cycles of at least one of the number of subsamples.

35-49. -49. (canceled)

50. A method of operating a transponder detection device that includes at least one processor, at least one nontransitory processor-readable medium communicatively coupled to the at least one processor and which stores at least one of instructions or data executable by the at least one processor, and one or more antennas, the method comprising:

for each of the one or more antennas,

obtaining a first set of subsamples, each of the subsamples associated with a respective delay period equal to a respective fraction of a nominal tag response signal period, the respective fractions different from one another, each of the subsamples in the first set of subsamples obtained by;

during each of a plurality of successive interrogation cycles associated with each subsample in the first set of subsamples,

emitting a first periodic electromagnetic interrogation signal during a transmit portion of the interrogation cycle, the first electromagnetic interrogation signal having a first interrogation signal frequency;

receiving electromagnetic signals during a receive response portion of the interrogation cycle that follows the transmit portion of the interrogation cycle; and

waiting the delay period of the one of the number of subsamples in the first set of subsamples to which the interrogation cycle is associated before a start of each of the successive interrogation cycles of the plurality of interrogation cycles;

obtaining a second set of subsamples, each of the subsamples associated with a respective delay period equal to a respective fraction of a nominal tag response signal period, the respective fractions different from one another, each of the subsamples in the second set of subsamples obtained by;

during each of a plurality of successive interrogation cycles associated with each subsample in the second set of subsamples,

emitting a second periodic electromagnetic interrogation signal during a transmit portion of the interrogation cycle, the second electromagnetic interrogation signal having a second interrogation signal frequency different from the first interrogation signal frequency;

receiving electromagnetic signals during a receive response portion of the interrogation cycle that follows the transmit portion of the interrogation cycle; and

waiting a delay period of the one of the number of subsamples in the second set of subsamples to which the interrogation cycle is associated before a start of each of the successive interrogation cycles of the plurality of interrogation cycles.

51-102. -102. (canceled)