Localization of objects within a conductive volume

Patent metadata

Field	Value
Publication number	US-10568540-B2
Application number	US-201514867716-A
Country	US
Kind code	B2
Filing date	Sep 28, 2015
Priority date	Sep 26, 2014
Publication date	Feb 25, 2020
Grant date	Feb 25, 2020

Abstract

An example method includes applying a localization signal to a source electrode positioned within a conductive volume and a ground electrode at a known location. Electrical activity is sensed at a plurality of sensor electrodes distributed across an outer surface of the conductive volume. The locations of each of the sensor electrodes and the location of the ground electrode being stored in memory as part of geometry data. The electrical activity sensed at each of the sensor electrodes is stored in the memory as electrical measurement data. The method also includes computing a location of the source electrode by minimizing a difference between respective pairs of source voltages determined for the plurality of sensor electrodes. The source voltage for each of the sensor electrodes is determined based on the electrical measurement data and the geometry data.

First claim

What is claimed is:

1. A system comprising:
a plurality of sensors configured to sense electrical activity at locations distributed across a conductive volume, locations of each of the plurality of sensors being predetermined with respect to a spatial coordinate system and stored in memory as geometry data;
a source electrode positioned within the conductive volume at an unknown location that is to be determined;
a signal generator to supply electrical energy to the source electrode, corresponding to a generated source voltage, which generates an electric field, a circuit path extending from the source electrode to an electrical ground at a position on an outer surface of the conductive volume, which is coupled to the signal generator; and
a location calculator implemented as instructions executed by a computer processor in the system, the location calculator configured to compute the location of the source electrode by minimizing a difference between determined source voltages that are determined for multiple pairs of the plurality of sensors, each determined source voltage being determined based on sensor measurements of voltage in response to the electric field for each respective one of the plurality of sensors and based on relative locations of the sensors determined from the geometry data,
wherein the difference between the determined source voltages is minimized according to the minimization function

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where
r i and r j define the locations of ith and jth sensors of the plurality of sensors, respectively,
V mi and V mj are the sensor measurements of voltage measured by the ith and jth sensors, respectively,
L gi is the distance between the ith sensor and the electrical ground,
L gi is the distance between the jth sensor and the electrical ground, and
r 0 is the location of the source electrode computed by the location calculator.

2. The system of claim 1 , wherein the location calculator is configured to compute the location of the source electrode based on the sensor measurements acquired concurrently for each of the plurality of sensors in response to the electric field.

3. The system of claim 2 , wherein the plurality of sensors includes at least three electrodes distributed across the conductive volume.

4. The system of claim 1 , wherein the geometry data specifying the predetermined location of each of the plurality of sensors comprises information generated by at least one of:
self-discovery, wherein the spatial distribution of the sensors with respect to each other or a neutral point is computed based on a programmed sequence of current or voltage applied among the sensors,
based on imaging data, or
a digitizer.

5. The system of claim 1 , further comprising a channel integrity detector implemented as instructions executed by a computer processor in the system, the channel integrity detector configured to identify for exclusion from subsequent analysis channels based on one or more of correlation of a channel's signal with respect to signals of spatially neighboring channels, amplitude of the channel's signal, the channel being a short circuit, and/or the channel being an open circuit, the geometry data and the sensor measurements for each identified channel being made unavailable for the computation by the location calculator.

6. The system of claim 1 , further comprising volume impedance data stored in the memory to characterize impedance of the conductive volume, the location calculator accounting for variations in the impedance of the con

Assignees

• Cardioinsight Technologies Inc

Inventors

• Jia Ping
• Zeng Qingguo
• Ramanathan Charulatha
• Bokan Ryan

Classifications

• A61B5/053

  Measuring electrical impedance or conductance of a portion of the body · CPC title

• A61B2562/046

  in a matrix array · CPC title

• A61B5/063 Primary

  using impedance measurements · CPC title

• A61B5/0538

  invasively, e.g. using a catheter · CPC title

• A61B2560/0223

  of calibration, e.g. protocols for calibrating sensors · CPC title