Deep electromagnetic rebar probe

A portable, non-destructive detection apparatus for determining at least a first attribute of an elongate, target object extending along an object axis and being disposed within a non-magnetic structure, the apparatus comprising:

• a) an input signal generator configured to generate a pulsed voltage electrical signal;
• b) an electromagnetic coupler extending in a coupler direction between first and second coupler ends and being positionable proximate the non-magnetic structure;
• c) a first transmitter connected to electromagnetic coupler and configured to generate a first pulsed electromagnetic interrogation signal based on the pulsed voltage electrical signal;
• d) a first receiver connected to electromagnetic coupler and spaced apart from the first transmitter, wherein when the first and second coupler ends are positioned adjacent the non-magnetic structure and the coupler direction is generally aligned with the object axis an electromagnetic circuit is formed comprising the target object, the electromagnetic coupler, the first transmitter and the first receiver, and wherein the first transmitter is configured to introduce the first pulsed electromagnetic interrogation signal through the non-magnetic structure and along the electromagnetic circuit and the first receiver is configured to receive a response electromagnetic signal that is induced in the target object and to generate a corresponding response electrical signal comprising time information and voltage information, wherein the first transmitter is disposed toward the first coupler end and first receiver is disposed toward the second coupler end, and wherein when the first and second coupler ends are positioned adjacent the non-magnetic structure at least one of the first transmitter and the first receiver are proximate the non- magnetic structure;
• e) a response signal processor configured to process the response electrical signal to determine the first attribute of the target object based on the time information and the voltage information and generate a corresponding first output signal;
• f) a user output module configured to generate a first user output based on the first output signal;
• g) a second transmitter connected to electromagnetic coupler and spaced apart from the first transmitter;
• and
• h a second receiver connected to electromagnetic coupler and spaced apart from the second transmitter;
• wherein when the first and second coupler ends are positioned adjacent the non-magnetic structure and the coupler direction is generally aligned with the object axis the second transmitter and second receiver at in the electromagnetic circuit, and wherein the second transmitter is configured to introduce the second pulsed electromagnetic interrogation signal through the non-magnetic structure and along the electromagnetic circuit and the second receiver is configured to receive the response electromagnetic signal that is induced in the target object and to generate a corresponding response electrical signal comprising time information and voltage information.

A portable, non-destructive detection apparatus for determining at least a first attribute of an elongate, target object extending along an object axis and being disposed within a non-magnetic structure, the apparatus comprising:

• a) an input signal generator configured to generate a pulsed voltage electrical signal;
• b) an electromagnetic coupler extending in a coupler direction between first and second coupler ends and being positionable proximate the non-magnetic structure;
• c) a first transmitter connected to electromagnetic coupler and configured to generate a first pulsed electromagnetic interrogation signal based on the pulsed voltage electrical signal;
• d) a first receiver connected to electromagnetic coupler and spaced apart from the first transmitter, wherein when the first and second coupler ends are positioned adjacent the non-magnetic structure and the coupler direction is generally aligned with the object axis an electromagnetic circuit is formed comprising the target object, the electromagnetic coupler, the first transmitter and the first receiver, and wherein the first transmitter is configured to introduce the first pulsed electromagnetic interrogation signal through the non-magnetic structure and along the electromagnetic circuit and the first receiver is configured to receive a response electromagnetic signal that is induced in the target object and to generate a corresponding response electrical signal comprising time information and voltage information;
• e) a response signal processor configured to process the response electrical signal to determine the first attribute of the target object based on the time information and the voltage information and generate a corresponding first output signal;
• f) a user output module configured to generate a first user output based on the first output signal;
• wherein the first attribute comprises one of:
• a) a representative cross-sectional area of the target object, wherein the response signal processor is configured to determine the first attribute based on a rate of change of a logarithm of a voltage of the response electrical signal with respect to time;
• and
• b) a representative depth of the target object from an outer surface of the non-magnetic structure, wherein the response signal processor is configured to determine the first attribute based on an amplitude of the logarithm of the voltage of the response electrical signal.