Abstract: A method for improving a performance of a metal detector, including: determining positions of a sensor head of the metal detector with respect to a coordinate system as the sensor head is moved on top of a ground; processing a receive signal received by the sensor head to produce a substantially ground balanced signal that is substantially insensitive to signals due to the ground; and actively controlling the step of processing based on one or more of the determined positions as the metal detector is moved on top of the ground; wherein, during a continuous use of the metal detector, the determined positions are processed to control, without any instruction or indication from an operator of the metal detector to do so, the step of processing the receive signal to produce the substantially ground balanced signal.

Abstract: Provided is a method for detecting a target using a metal detector, including transmitting a transmit magnetic field using a transmitter; determining positions of a receiver of the metal detector as the receiver changes positions; receiving receive magnetic fields due to the transmit magnetic field to produce receive signals associated with positions using the receiver and receive electronics; and producing an audio output signal. The audio output signal is dependent on one or more receive signals associated with positions related to a current determined position in a selected relationship.

Abstract: A method for detecting a target using a metal detector, including: transmitting a transmit magnetic field using a transmitter; receiving a receive magnetic field due to the transmit magnetic field to produce a receive signal using a receiver and receive electronics; processing the receive signal using at least one function to produce an indicator output, wherein the at least one function is controllable such that the properties of the indicator output is controllable in terms of: (a) an amount of cancellation of signals due to soil; wherein the amount of cancellation of signals due to soil is higher than an amount of cancellation of signals due to the target; and (b) a sensitivity of the indicator output to the target and broadband electromagnetic interference (EMI); wherein controlling the at least one function in a particular direction changes the at least one function from a first state more suitable for high ground response environments to a second state more suitable for medium ground response environmen

Abstract: A method for improving a metal detector, including: processing at least one receive signal due to a receive magnetic field using at least two functions to produce two processed signals, the at least two functions are selected such that the first processed signal is more sensitive to deeply buried targets than the second processed signal; and the second processed signal is more sensitive to shallow-buried conductive objects with characteristic frequency greater than 100 kHz than the first processed signal but not sensitive to saline soil, and that the two processed signals substantially complement each other in terms of sensitivity to targets in terms of target frequency and detection depth; and processing the two processed signals to produce at least one output signal which is sensitive to deeply buried low-frequency targets, shallow-buried low-frequency targets and shallow-buried high-frequency targets while signals due to saline soil are substantially rejected from the output signal.

Abstract: A method for detecting a target using a metal detector, including: transmitting a transmit magnetic field using a transmitter; receiving a receive magnetic field due to the transmit magnetic field to produce a receive signal using a receiver and receive electronics; processing the receive signal using at least one function to produce an indicator output, wherein the at least one function is controllable such that the properties of the indicator output is controllable in terms of: (a) an amount of cancellation of signals due to soil; wherein the amount of cancellation of signals due to soil is higher than an amount of cancellation of signals due to the target; and (b) a sensitivity of the indicator output to the target and broadband electromagnetic interference (EMI); wherein controlling the at least one function in a particular direction changes the at least one function from a first state more suitable for high ground response environments to a second state more suitable for medium ground response environmen

Abstract: A method for detecting a target using a metal detector, including: transmitting a transmit magnetic field using a transmitter based on a multiple-frequency transmit signal; receiving a receive magnetic field due to the transmit magnetic field using a receiver to produce a receive signal; processing the receive signal using at least two sets of demodulation functions; each set including at least two demodulation functions that substantially complement each other such that when at a particular time one has a low sensitivity to a particular noise signal, the other has an effective sensitivity to detect that particular noise signal; each of at least two of the at least two demodulation functions is sensitive to at least two frequencies; and each of at least two of the at least two sets of demodulation functions is sensitive to different frequencies of the transmit signal; selecting a set of demodulation functions from the at least two sets of demodulation functions which produces the lowest noise in the step of p

Abstract: A method for improving a performance of a metal detector, including: determining positions of a sensor head of the metal detector with respect to a coordinate system as the sensor head is moved on top of a ground; processing a receive signal received by the sensor head to produce a substantially ground balanced signal that is substantially insensitive to signals due to the ground; and actively controlling the step of processing based on one or more of the determined positions as the metal detector is moved on top of the ground; wherein, during a continuous use of the metal detector, the determined positions are processed to control, without any instruction or indication from an operator of the metal detector to do so, the step of processing the receive signal to produce the substantially ground balanced signal.

Abstract: A method for improving a metal detector, including: processing at least one receive signal due to a receive magnetic field using at least two functions to produce two processed signals, the at least two functions are selected such that the first processed signal is more sensitive to deeply buried targets than the second processed signal; and the second processed signal is more sensitive to shallow-buried conductive objects with characteristic frequency greater than 100 kHz than the first processed signal but not sensitive to saline soil, and that the two processed signals substantially complement each other in terms of sensitivity to targets in terms of target frequency and detection depth; and processing the two processed signals to produce at least one output signal which is sensitive to deeply buried low-frequency targets, shallow-buried low-frequency targets and shallow-buried high-frequency targets while signals due to saline soil are substantially rejected from the output signal.

Abstract: A method for detecting a target in a soil using a metal detector, including: generating a transmit magnetic field for transmission into the soil based on a transmit signal; receiving a receive magnetic field; providing a receive signal induced by the receive magnetic field; processing the receive signal for producing a set of data which has effects of signals from the soil reduced therein or removed therefrom; producing at least two components of a form of at least one time constant spectrum based on the set of data; and producing, at least one indicator output signal based on the at least two components for indicating the presence and/or identity of the target when the target is within, an influence of the transmit magnetic field.

Abstract: A method for detecting a target in a soil using a metal detector, including: generating a transmit magnetic field for transmission into the soil based on a transmit signal; receiving a receive magnetic field; providing a receive signal induced by the receive magnetic field; determining, based on the receive signal, a model of at least two independent components of the receive signal which are due to signals from the soil; processing the receive signal to produce a set of data which is with effects of the signals from the soil reduced therein or removed therefrom by fitting the model to the receive signal, then subtracting the fitted model from the receive signal; and producing, based on the set of data, an indicator output signal for indicating a presence and/or identity of the target.

Abstract: A method for detecting a target in a soil using a metal detector, including: generating a transmit magnetic field for transmission into the soil based on a transmit signal; receiving a receive magnetic field; providing a receive signal induced by the receive magnetic field; processing the receive signal for producing a set of data which has effects of signals from the soil reduced therein or removed therefrom; producing at least two components of a form of at least one time constant spectrum based on the set of data; and producing, at least one indicator output signal based on the at least two components for indicating the presence and/or identity of the target when the target is within, an influence of the transmit magnetic field.

Abstract: A method for detecting a target in a soil using a metal detector, including: generating a transmit magnetic field for transmission into the soil based on a transmit signal; receiving a receive magnetic field; providing a receive signal induced by the receive magnetic field; determining, based on the receive signal, a model of at least two independent components of the receive signal which are due to signals from the soil; processing the receive signal to produce a set of data which is with effects of the signals from the soil reduced therein or removed therefrom by fitting the model to the receive signal, then subtracting the fitted model from the receive signal; and producing, based on the set of data, an indicator output signal for indicating a presence and/or identity of the target.