Apparatus and method for measuring an embedded object

A method for measuring an object embedded in a structure, the method comprising:

• arranging a first antenna on a surface of the structure, such that a polarization of the first antenna is perpendicular to an orientation axis of the embedded object;
• arranging a second antenna on the surface of the structure, such that a polarization of the second antenna is parallel to the orientation axis of the embedded object, the second antenna being coupled perpendicularly to the first antenna;
• configuring the antennas to transmit and receive radio signals for measurement;
• moving the antennas across the surface of the structure;
• transmitting radio signals from the antennas into the structure as the antennas move across the structure and pass over the embedded object;
• measuring, from each antenna, the radio signals transmitted from the antennas and reflected from the embedded object;
• generating a first representation of the embedded object based on the measured radio signals from the first antenna;
• generating a second representation of the embedded object based on the measured radio signals from the second antenna;
• calculating respective maximum amplitudes of the first and second representations in a time domain;
• calculating a power ratio of the measured radio signals based on the respective maximum amplitudes of the first and second representations in the time domain, the power ratio defined as a square of a ratio between the maximum amplitude of the first representation and the maximum amplitude of the second representation;
• and measuring a size of the embedded object based on the power ratio.

A method for measuring an object embedded in a structure, the method comprising:

• configuring an antenna to transmit and receive radio signals for measurement;
• arranging the antenna in a first orientation on a surface of the structure, such that a polarization of the antenna is one of perpendicular and parallel to an orientation axis of the embedded object;
• moving the antenna in the first orientation across the surface of the structure;
• transmitting radio signals from the antenna in the first orientation into the structure as the antenna moves across the structure and passes over the embedded object;
• measuring, from the antenna in the first orientation, the radio signals transmitted from the antenna and reflected from the embedded object;
• generating a first representation of the embedded object based on the measured radio signals from the antenna in the first orientation;
• arranging the antenna in a second orientation on the surface of the structure, such that the polarization of the antenna is the other of perpendicular and parallel to the orientation axis of the embedded object;
• moving the antenna in the second orientation across the surface of the structure;
• transmitting radio signals from the antenna in the second orientation into the structure as the antenna moves across the structure and passes over the embedded object;
• measuring, from the antenna in the second orientation, the radio signals transmitted from the antenna and reflected from the embedded object;
• generating a second representation of the embedded object based on the measured radio signals from the antenna in the second orientation;
• calculating respective maximum amplitudes of the first and second representations in a time domain;
• calculating a power ratio of the measured radio signals based on the respective maximum amplitudes of the first and second representations in the time domain, the power ratio defined as a square of a ratio between the maximum amplitude of the first representation and the maximum amplitude of the second representation;
• and measuring a size of the embedded object based on the power ratio.