SYSTEM FOR CALIBRATING AN ELECTROMAGNETIC NAVIGATION SYSTEM

• US 20180116729A1
• Filed: 10/28/2016
• Published: 05/03/2018
• Est. Priority Date: 10/28/2016
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: MORGAN, SEAN M., KOYRAKH, LEV A.
• Granted Patent: US 10,792,106 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 1/00158 using magnetic field
• CPC Class Codes: A61B 1/2676 Bronchoscopes
• CPC Class Codes: A61B 2017/00809 Lung operations
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2034/2072 Reference field transducer attached to an instrument or patient
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 5/062 using magnetic field

Abstract

A system for calibrating an electromagnetic navigation system is provided. The system includes an antenna assembly having a substrate, multiple pairs of transmit coils, multiple receive coils, multiple input terminals, and multiple output terminals. The substrate includes multiple layers, and each of the transmit coils is deposited on a respective one of the layers and each of the receive coils is deposited on another respective one of the layers. Each of the pairs of transmit coils corresponds to a respective one of the receive coils. Each of the transmit coils is coupled to a respective one of the input terminals, and each of the receive coils is coupled to a respective one of the output terminals.

Claims

1. A system for calibrating an electromagnetic navigation system, comprising:

an antenna assembly, including;

a substrate including a plurality of layers;

a plurality of pairs of transmit coils, each of the transmit coils being deposited on a respective one of the plurality of layers;

a plurality of receive coils, each of the receive coils being deposited on a respective one of the plurality of layers, and

each of the plurality of pairs of transmit coils corresponding to a respective one of the plurality of receive coils;

a plurality of input terminals coupled to the plurality of pairs of transmit coils, respectively; and

a plurality of output terminals coupled to the plurality of receive coils, respectively.

2. The system of claim 1, wherein each of the plurality of receive coils is arranged on a respective one of the plurality of layers that is located in between a pair of the plurality of layers on which the corresponding pair of transmit coils are respectively deposited.

3. The system of claim 1, wherein each of the plurality of pairs of transmit coils forms a Helmholtz pair.

4. The system of claim 1, wherein the antenna assembly is an impedance-controlled antenna assembly.

5. The system of claim 1, further comprising:

a computing device including;

a processor coupled to the plurality of pairs of transmit coils by way of the plurality of input terminals, respectively, and coupled to the plurality of receive coils by way of the plurality of output terminals, respectively; and

a memory including instructions that, when executed by the processor, cause the processor to;

transmit, by way of at least one of the plurality of pairs of transmit coils, a signal having a first magnitude value and a first phase value,

receive the signal by way of at least one of the receive coils;

compute a non-calibrated in-phase component and a non-calibrated quadrature component based on the first magnitude value and the first phase value;

compute a calibrated phase value based on the non-calibrated in-phase component and the non-calibrated quadrature component;

compute a calibrated in-phase component based on the calibrated phase value, the non-calibrated in-phase component, and the non-calibrated quadrature component;

compute a calibrated quadrature component based on the calibrated phase value, the non-calibrated in-phase component, and the non-calibrated quadrature component;

compute a calibrated magnitude value based on the calibrated in-phase component; and

store the calibrated phase value and the calibrated magnitude value in a table for use during an electromagnetic navigation procedure.

6. The system of claim 5, wherein the transmitting of the signal by way of one or more of the plurality of pairs of transmit coils and the receiving of the signal by way of one or more of the plurality of receive coils are synchronized to one another.

7. The system of claim 5, wherein the memory stores further instructions that, when executed by the processor, cause the processor to:

perform a lookup in at least one of a sine table or a cosine table based on the first magnitude value and the first phase value, wherein the computing of at least one of the non-calibrated in-phase component or the non-calibrated quadrature component is further based on a result of the performing of the lookup.

8. The system of claim 5, wherein the memory stores further instructions that, when executed by the processor, cause the processor to compute the calibrated phase value according to the equation:

9. The system of claim 5, wherein the memory stores further instructions that, when executed by the processor, cause the processor to compute the calibrated in-phase component according to the equation:

I_calibrated=I_{non-calibrated}×

cos(θ

_cal)+Q_{non-calibrated}×

sin(θ

_cal),

where I_calibrated represents the calibrated in-phase component, I_{non-calibrated} represents the non-calibrated in-phase component, θ

_cal represents the calibrated phase value, and Q_{non-calibrated} represents the non-calibrated quadrature component.

10. The system of claim 5, wherein the memory stores further instructions that, when executed by the processor, cause the processor to compute the calibrated quadrature component according to the equation:

Q_calibrated=−

I_{non-calibrated}×

sin(θ

_cal)+Q_{non-calibrated}×

cos(θ

_cal),

where Q_calibrated represents the calibrated quadrature component, I_{non-calibrated} represents the non-calibrated in-phase component, θ

_cal represents the calibrated phase value, and Q_{non-calibrated} represents the non-calibrated quadrature component.

11. The system of claim 5, wherein the memory stores further instructions that, when executed by the processor, cause the processor to compute the calibrated magnitude value according to the equation:

12. The system of claim 5, wherein the memory stores further instructions that, when executed by the processor, cause the processor to:

determine whether the calibrated magnitude value is less than zero; and

in response to a determination that the calibrated magnitude value is less than zero;

compute a second calibrated phase value, and

recompute the calibrated magnitude value, the calibrated in-phase component, and the calibrated quadrature component based on the second calibrated phase value.

13. The system of claim 5, wherein the memory stores further instructions that, when executed by the processor, cause the processor to:

determine whether the calibrated magnitude value is less than zero and whether the calibrated phase value is less than or equal to zero; and

in response to a determination that the calibrated magnitude value is less than zero and the calibrated phase value is less than or equal to zero;

compute a second calibrated phase value according to the equation;

θ

_cal′

=θ

_cal+π

,

where θ

_cal′

represents the second calibrated phase value and θ

_cal represents the calibrated phase value; and

recompute the calibrated magnitude value, the calibrated in-phase component, and the calibrated quadrature component based on the second calibrated phase value.

14. The system of claim 5, wherein the memory stores further instructions that, when executed by the processor, cause the processor to:

determine whether the calibrated magnitude value is less than zero and whether the calibrated phase value is greater than zero; and

in response to a determination that the calibrated magnitude value is less than zero and the calibrated phase value is greater than zero;

compute a second calibrated phase value according to the equation;

θ

_cal′

=θ

_cal−

π

,

where θ

_cal′

represents the second calibrated phase value and θ

_cal represents the calibrated phase value; and

recompute the calibrated magnitude value, the calibrated in-phase component, and the calibrated quadrature component based on the second calibrated phase value.

15. The system of claim 5, wherein the memory stores further instructions that, when executed by the processor, cause the processor to:

receive a second signal having a second magnitude value and a second phase value;

compute a second non-calibrated in-phase component and a second non-calibrated quadrature component based on the second magnitude value and the second phase value; and

compute a corrected in-phase component and a corrected quadrature component based on the calibrated phase value, the calibrated magnitude value, the second non-calibrated in-phase component, and the second non-calibrated quadrature component.

16. The system of claim 15,

wherein the memory stores further instructions that, when executed by the processor, cause the processor to compute the corrected in-phase component according to the equation:

I_c=M_cal×

((I_non-cal2)×

cos(θ

_cal)+(Q_non-cal2)×

sin(θ

_cal)),

where I_c represents the corrected in-phase component, M_cal represents the calibrated magnitude value, I_non-cal2 represents the second non-calibrated in-phase component, θ

_cal represents the calibrated phase value, and Q_non-cal2 represents the second non-calibrated quadrature component.

17. The system of claim 15,

wherein the memory stores further instructions that, when executed by the processor, cause the processor to compute the corrected quadrature component according to the equation:

Q_c=M_cal×

(−

(I_non-cal2)×

sin(θ

_cal)+(Q_non-cal2)×

cos(θ

_cal)),

where Q_c represents the corrected quadrature component, M_cal represents the calibrated magnitude value, I_non-cal2 represents the second non-calibrated in-phase component, θ

_cal representsthe calibrated phase value, and Q_non-cal2 represents the second non-calibrated quadrature component.

18. A system for calibrating an electromagnetic navigation system, comprising:

an antenna assembly, including;

a substrate including a plurality of layers;

a plurality of pairs of transmit coils, each of the transmit coils being deposited on a respective one of the plurality of layers;

a plurality of pairs of receive coils, each of the receive coils being deposited on a respective one of the plurality of layers, and

each of the plurality of pairs of transmit coils corresponding to a respective one of the plurality of pairs of receive coils;

a plurality of input terminals coupled to the plurality of pairs of transmit coils, respectively; and

a plurality of output terminals coupled to the plurality of pairs of receive coils, respectively.

19. The system of claim 18, further comprising:

a computing device including;

a processor coupled to the plurality of pairs of transmit coils by way of the plurality of input terminals, respectively, and coupled to the plurality of pairs of receive coils by way of the plurality of output terminals, respectively; and

a memory including instructions that, when executed by the processor, cause the processor to;

transmit, by way of at least one of the plurality of pairs of transmit coils, a signal having a first magnitude value and a first phase value,

receive the signal by way of at least one of the plurality of pairs of receive coils;

compute a non-calibrated in-phase component and a non-calibrated quadrature component based on the first magnitude value and the first phase value;

compute a calibrated phase value based on the non-calibrated in-phase component and the non-calibrated quadrature component;

compute a calibrated in-phase component based on the calibrated phase value, the non-calibrated in-phase component, and the non-calibrated quadrature component;

compute a calibrated quadrature component based on the calibrated phase value, the non-calibrated in-phase component, and the non-calibrated quadrature component;

compute a calibrated magnitude value based on the calibrated in-phase component; and

store the calibrated phase value and the calibrated magnitude value in a table for use during an electromagnetic navigation procedure.

20. The system of claim 18, wherein each of the plurality of pairs of receive coils includes a first receive coil deposited on a first layer of the plurality of layers and a second receive coil deposited on a second layer of the plurality of layers, wherein the first layer and the second layer are located in between a pair of the plurality of layers on which the corresponding pair of transmit coils are respectively deposited.