Systems and methods for impedance analysis of conductive medium
Systems and methods are disclosed for classifying a condition of an entity that includes a conductive medium having multiple conductive paths, using a pattern recognition strategy to classify a signature constructed from impedance-interrogation measurements and optionally including inputs from other informative sources which may be external to the system.
1. A system for classifying a condition of an entity comprising a plurality of points separated by a conductive medium offering a plurality of conductive paths between the points, the system comprising:
a signal source for applying one or more electrical signals at one or more points;
a measuring component for measuring one or more electrical properties of the entity;
an interface for receiving at least one informative value from a source external to the system;
a controller adapted and configured to (a) control the signal source and the measuring component to make a plurality of impedance-interrogation measurements, (b) produce an output comprising the values obtained from the plurality of impedance-interrogation measurements; and (c) receive from the interface at least one informative value from a source external to the system;
a signature processor adapted and configured to process the plurality of impedance-interrogation measurements and the at least one informative value from a source external to the system into a signature; and
a pattern recognizer programmed to classify, from the signature, a condition of the entity by machine execution of a pattern recognition strategy.
2. The system of claim 1 , wherein each impedance-interrogation measurement comprises at least one value obtained by a method comprising applying an interrogation signal at at least one of the points and measuring an electrical quantity comprising a response to the interrogation signal, wherein the response may comprise a null response.
3. The system of claim 1 , wherein the entity comprises a living organism and the conductive medium comprises all or a portion of the living organism.
4. The system of claim 1 , wherein classifying a condition of an entity comprises classifying the condition of the entity as corresponding or not corresponding to a pathological state.
5. The system of claim 1 , wherein classifying a condition of an entity comprises classifying the condition of the entity as corresponding or not corresponding to a specific pathological state.
6. The system of claim 1 , wherein applying an electrical signal comprises inducing an ionic current in the conductive medium.
7. The system of claim 1 , wherein the signature comprises a feature vector.
8. The system of claim 1 , wherein the signature comprises a feature vector and the pattern recognition strategy comprises comparing said feature vector with at least one reference feature vector.
9. The system of claim 1 , wherein the signature comprises a feature vector and the pattern recognition strategy comprises classifying the feature vector using a pattern recognizer trained on a training set of reference feature vectors.
10. The system of claim 1 , wherein the signature comprises a feature vector and the pattern recognition strategy comprises classifying the feature vector using a pattern recognition method selected from: a neural network, a genetic algorithm, an evolutionary algorithm, a deep learning algorithm, a supervised machine learning algorithm, an unsupervised machine learning algorithm, a dimension reduction strategy, a support vector machine, a linear classifier, a binary tree classifier, a Gaussian process classifier, a k-nearest neighbor classifier, and a Bayesian network classifier.
11. The system of claim 1 , wherein at least one impedance-interrogation measurement comprises an estimate of an impedance property of the conductive medium.
12. The system of claim 1 , wherein the at least one informative value from a source external to the system is not a value obtained from an impedance-interrogation measurement.
13. The system of claim 1 , wherein the plurality of impedance-interrogation measurements are not processed into a graphical representation or image.
14. The system of claim 1 , wherein processing the plurality of impedance-interrogation measurements and the at least one informative value from a source external to the system into a signature comprises selecting a predetermined set of impedance-interrogation measurements or values derived therefrom for inclusion, and ordering the measurements or values and the at least one informative value in a predetermined manner.
15. The system of claim 1 , wherein processing the plurality of impedance-interrogation measurements into a signature comprises assigning weights to the values comprising the signature.
16. The system of claim 1 , wherein the interface for receiving at least one informative value from a source external to the system comprises a user interface adapted and configured for entry of the at least one informative value by a user.
17. The system of claim 1 , wherein the at least one informative value from a source external to the system comprises non-numeric data.
18. The system of claim 1 , wherein the at least one informative value from a source external to the system comprises textual data.
19. The system of claim 1 , wherein the at least one informative value from a source external to the system comprises an image.
20. The system of claim 1 , wherein the at least one informative value from a source external to the system is not a sensor output.