Method, apparatus and article for detection of transponder tagged objects, for example during surgery
First Claim
1. A transponder detection device, comprising:
- an antenna;
a processor operatively coupled to the antenna; and
a nontransitory processor-readable medium communicatively coupled to the processor and that stores at least one of instructions or data executable by the processor, which cause the processor to;
execute a number of successive interrogation cycles, the number of successive interrogation cycles greater than one, wherein, during each of the number of successive interrogation cycles the transponder detection device,emits a periodic electromagnetic interrogation signal during a transmit portion of the interrogation cycle;
receives electromagnetic signals during a receive response portion of the interrogation cycle that follows the transmit portion of the interrogation cycle; and
waits a respective delay period before a respective start of each of the successive interrogation cycles of the number of interrogation cycles, each respective delay period for the number of interrogation cycles equal to a respective fraction of a nominal tag response signal period, and, for each one of the successive interrogation cycles of the number of interrogation cycles, the respective delay period is different than at least one other respective delay period of an interrogation cycle of the number of successive interrogation cycles by a duration equal to the nominal tag response signal period divided by the number of successive interrogation cycles.
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Accused Products
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.
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Citations
20 Claims
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1. A transponder detection device, comprising:
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an antenna; a processor operatively coupled to the antenna; and a nontransitory processor-readable medium communicatively coupled to the processor and that stores at least one of instructions or data executable by the processor, which cause the processor to; execute a number of successive interrogation cycles, the number of successive interrogation cycles greater than one, wherein, during each of the number of successive interrogation cycles the transponder detection device, emits a periodic electromagnetic interrogation signal during a transmit portion of the interrogation cycle; receives electromagnetic signals during a receive response portion of the interrogation cycle that follows the transmit portion of the interrogation cycle; and waits a respective delay period before a respective start of each of the successive interrogation cycles of the number of interrogation cycles, each respective delay period for the number of interrogation cycles equal to a respective fraction of a nominal tag response signal period, and, for each one of the successive interrogation cycles of the number of interrogation cycles, the respective delay period is different than at least one other respective delay period of an interrogation cycle of the number of successive interrogation cycles by a duration equal to the nominal tag response signal period divided by the number of successive interrogation cycles.
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2. A transponder detection device, comprising:
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an antenna; a processor operatively coupled to the antenna; and a nontransitory processor-readable medium communicatively coupled to the processor and that stores at least one of instructions or data executable by the processor, which cause the processor to; obtain 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, the transponder detection device, emits via the antenna a periodic electromagnetic interrogation signal during a transmit portion of the interrogation cycle; receives via the antenna electromagnetic signals during a receive response portion of the interrogation cycle that follows the transmit portion of the interrogation cycle; and waits a 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, 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 respective delay period associated with each one of the subsamples is different than the delay period associated with at least one other one of the subsamples by a duration approximately equal to the nominal tag response signal period divided by the number of subsamples. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A transponder detection device, comprising:
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one or more antennas; a processor operatively coupled to the one or more antennas; and a nontransitory processor-readable medium communicatively coupled to the processor and that stores at least one of instructions or data executable by the processor, which cause the processor to; for each of the one or more antennas, obtain a set of subsamples, the set of subsamples comprising 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 subsamples in the set of subsamples obtained by; during each of a plurality of interrogation cycles in each subsample in the set of subsamples, the transponder detection device,
emits a periodic electromagnetic interrogation signal during a transmit portion of the interrogation cycle, the electromagnetic interrogation signal having an interrogation signal frequency;
receives electromagnetic signals during a receive response portion of the interrogation cycle that follows the transmit portion of the interrogation cycle; and
waits the respective 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, wherein, for each successive pair of subsamples in the set of subsamples, the delay period associated with a successive one of the pairs of subsamples is less than the delay period associated with an immediately next successive one of the pairs of subsamples by a duration equal to the nominal tag response signal period divided by the number of subsamples.
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Specification