A security screening apparatus for use in detecting ferromagnetic objects comprises a detector apparatus which comprises a housing that supports at least one magnetic sensor arranged to produce a signal indicative of an ambient magnetic field or gradient over a zone of sensitivity which extends away from the housing, the size of the zone being large enough to contain the whole body of the person, and a signal processing circuit which receives as an input the signal from the magnetic sensor and which, in response to a change in the signal produces an alert signal. A beacon that comprises a light source is able to emit at least two visually distinct colours of light, and a control means controls the light source such that in a first condition in the absence of the alert signal the beacon emits a first colour light and in a second condition corresponding to the presence of the alert signal the beacon emits a second, different, colour of light. The light source is arranged such that the position and/or size and/or shape of the illuminated area of the light source in the first condition is different from the position and/or size and or shape of the illuminated area of the light source in the second condition.

Disclosed is a magnetotelluric inversion method based on a fully convolutional neural network. The magnetotelluric inversion method includes: constructing a multi-dimensional geoelectric model; constructing a fully convolutional neural network structure model to obtain initialized fully convolutional neural network model parameters; training and testing the fully convolutional neural network structure model based on the training sets and the test sets to obtain optimized fully convolutional neural network structure model parameters; determining whether training of the fully convolutional neural network structure model is completed according to fitting error changes corresponding to the training sets and the test sets; and finally, inputting measured apparent resistivity into a trained fully convolutional neural network structure model for inversion, and further optimizing the fully convolutional neural network structure model by analyzing precision of an inversion result until an inversion fitting error satisfies a set error requirement.

The present invention, thanks to the horizontal positional tracking unit (20)—mounted to a hand-held metal detector (10)—consisting of optical flow sensor lens (22), an optical flow sensor camera (21), an optical flow sensor processor (23), a height sensor (24) and an IMU sensor (25); allows the calculation of the depth of the target (60) by tracking the horizontal position while the user freely sweeps the search head (11) of the metal detector (10) with the “optical flow” method and using the metal detection signals received from many point positions around the detected target center with this position; so it relates to a method of measuring a target depth and a metal detector using this method, which allow calculation to be made independently of the type and practical the size of the metal.

Disclosed are methods and apparatus for identifying non-metallic subterranean structures using amorphous metal markers associated with the structures. Some examples will include the amorphous metal in the form of one or more sections of an amorphous metal foil within a protective enclosure sufficient to physically isolate the amorphous metal foil from the surrounding Earth. The amorphous metal foil and enclosure may be in the form of a tape which either will be secured to, or placed proximate the subterranean structure, which may be, for example, a pipe or conduit, or other non-metallic structure.

A method and system for detecting electrically conductive objects such as tramp metal embedded in a load of mineral ore/earth within a detection space of an earth moving receptacle. A magnetic signal pulse is projected into a detection space of the receptacle by an antennae loop surrounding the detection space. The magnetic response of the system is monitored and analyzed to determine the presence or absence of electrically conductive objects in the loose material within the detection space.

A method for locating a buried casing stub may comprise a) identifying a target region, b) providing at each of a plurality of survey points in the target region a casing stub locator that includes a vector magnetometer, c) measuring the magnetic field at each of the survey points using the vector magnetometer so as to generate a plurality of magnetic field measurements, d) using the magnetic field measurements to generate a model of the magnetic field of the target region, e) fitting the model generated in step d) to a selected model of a magnetic anomaly created by the casing stub so as to generate model fit information (MFI), and f) locating the casing stub using the MFI. At each survey point, an expected Earth magnetic field can be subtracted from the measured magnetic field. A total station can measure the position and/or the azimuth of the package.

A foreign object detector for detecting a foreign object between a transmission pad and a reception pad of a wireless charging system can include a plurality of object detectors; and a detection circuit configured to detect an object based on data received from the plurality of object detectors, in which each of the plurality of object detectors includes a first coil part including a coil wound in a first rotation direction; and a second coil part stacked on the first coil part and including a coil wound in a second rotation direction different from the first rotational direction, and in which each of the plurality of object detectors is connected in series or in parallel with one another.

Utility locators for providing information about hidden or buried pipes or other cavities are disclosed. A locator may be configured to provide positional information associated with the buried utility based on signals received from a line trace signal and a sonde signal and present the positional information on a visual display or other output device.

Front end circuits and associated apparatus, systems, and methods for use in electronic devices such as buried utility locators are disclosed. The circuits include receivers and filters on input signals that are coupled to ground rather than differentially. A multiplexing circuit allows shared use of amplifiers, and analog-to-digital converters via a switching mechanism for selectively making or breaking electrical connection to the receiver channels for efficient sharing of electronics resources while minimizing crosstalk interference and advantageously reducing costs.

A method for locating a buried casing stub may comprise a) identifying a target region, b) providing at each of a plurality of survey points in the target region a casing stub locator that includes a vector magnetometer, c) measuring the magnetic field at each of the survey points using the vector magnetometer so as to generate a plurality of magnetic field measurements, d) using the magnetic field measurements to generate a model of the magnetic field of the target region, e) fitting the model generated in step d) to a selected model of a magnetic anomaly created by the casing stub so as to generate model fit information (MFI), and f) locating the casing stub using the MFI. At each survey point, an expected Earth magnetic field can be subtracted from the measured magnetic field. A total station can measure the position and/or the azimuth of the package.