Abstract: Detection and recognition of taggant substances having predefined zero external field magnetic resonance signatures. An object comprising taggant substance(s) is irradiated with a sequence of specific excitation pulses of electromagnetic radiation within a predetermined time and frequency scanning pattern, responsive nuclear spin echo signals are received from the object with a predetermined time and frequency acquisition pattern and data indicative thereof is generated. The scanning and acquisition patterns used permit successive transmission of pulses of multiple frequencies using a two-pulse spin-echo excitation technique, or a steady state-spin echo excitation technique, and successive acquisition of multiple nuclear spin echo response signals, within a time slot between two successive excitation pulses of a specific excitation frequency.

Abstract: A system and method for rapid acquisition of MRI data at multiple points in time in an.

Abstract: A probe for use in Magnetic Resonance Force Microscopy (MRFM) to provide an image of a sample comprising: a magnetic field source adapted to orient the spin of the nuclei in a sample; a detector capable of detecting a magnetic field comprising an oscillator; at least one conductor substantially surrounding the oscillator for forming a RF antenna for transmitting a radio frequency electromagnetic field; whereby the at least one conductor transmits a radio frequency electromagnetic field that influences the nuclei in the sample, and whereby the detector detects how the nuclei are influenced through the oscillations of the oscillator to provide identification information concerning the content of the sample. Also included is a method for magnetic resonance force microscopy of a sample.

Abstract: According to one embodiment, a magnetic resonance imaging apparatus includes a spectrum acquisition unit, a resonance frequency acquisition unit and an imaging unit. The spectrum acquisition unit is configured to acquire frequency spectra of magnetic resonance signals from an object while changing a suppression effect or an enhancing effect of signals from a specific material. The resonance frequency acquisition unit is configured to obtain a resonance frequency of the specific material or another material based on an index representing a difference in intensities of signals from the specific material or the another material between the frequency spectra. The imaging unit is configured to perform imaging using a radio frequency pulse having a center frequency set to the resonance frequency of the specific material or the another material.

Abstract: Formation testing systems and methods may inject fluids into a formation to initiate fractures and facilitate measurements of various formation properties. In accordance with certain disclosed embodiments, the injection tools are further provided with nuclear magnetic resonance (NMR) sensors to monitor the injected fluids and provide measurements of near-borehole fracture orientations and volumes. Contrast agents and/or magnetic resonance imaging (MRI) techniques may be employed. The fluid injection may occur via an extendible isolation pad, via a fracturing jet, or via an injection port in an isolated region of the borehole. The systems may employ pressure monitoring in conjunction with the NMR sensors to further enhance estimates of formation and fracture properties.

Abstract: Illustrative embodiments are directed to applying a nuclear magnetic resonance sequence to a substance within an inhomogeneous static magnetic field. Various embodiments include applying a series of refocusing pulses to the substance, each refocusing pulse in the series of refocusing pulses having at least two segments, and a total pulse duration less than or equal to approximately 1.414 times T180. Various embodiments can further include applying an excitation pulse to the substance in the inhomogeneous static magnetic field, where the excitation pulse generates an initial magnetization that is aligned with a refocusing axis produced by a refocusing cycle that is performed after the excitation pulse.

Abstract: One embodiment of the invention includes a magnetometer system. The system includes a sensor cell comprising alkali metal particles and a probe laser configured to provide a probe beam through the sensor cell. The system also includes a detection system configured to implement nuclear magnetic resonance (NMR) detection of a vector magnitude of an external magnetic field in a first of three orthogonal axes based on characteristics of the probe beam passing through the sensor cell and to implement electron paramagnetic resonance (EPR) detection of a vector magnitude of the external magnetic field in a second and a third of the three orthogonal axes based on the characteristics of the probe beam passing through the sensor cell. The system further includes a controller configured to calculate a scalar magnitude of the external magnetic field based on the magnitude of the external magnetic field in each of the three orthogonal axes.

Abstract: Encapsulated fluorescent metal nanoparticles for radiation detection comprising metal ions in an aqueous solution encapsulated in a nanocapsule, wherein the metal ions form atoms when exposed to gamma-ray initiated reduction of the ions and then aggregate to form fluorescent nanoparticles.

Abstract: Hundreds of thousands of concrete bridges and hundreds of billions of tons of concrete require characterization with time for corrosion. Accordingly, protocols for rapid testing and improved field characterization systems that automatically triangulate electrical resistivity and half-cell corrosion potential measurements would be beneficial allowing discrete/periodic mapping of a structure to be performed as well as addressing testing for asphalt covered concrete. Further, it is the low frequency impedance of rebar in concrete that correlates to corrosion state but these are normally time consuming vulnerable to noise. Hence, it would be beneficial to provide a means of making low frequency electrical resistivity measurements rapidly. Further, prior art techniques for electrical rebar measurements require electrical connection be made to the rebar which increases measurement complexity/disruption/repair/cost even when no corrosion is identified.

Abstract: In a magnetic resonance (MR) imaging method and apparatus, multiple diagnostic scans are obtained of an examination subject during an imaging session. An initial reference scan of the subject is obtained at the beginning of the session and, as the session proceeds, an automatic determination is made before each diagnostic scan is obtained as to whether the immediately preceding reference scan is still valid, primarily be checking whether an amount of patient movement has occurred that renders the immediately preceding reference scan invalid. Either a new reference scan is obtained before the next diagnostic scan, or, if still valid, the immediately preceding reference scan is used for the next diagnostic scan.

Abstract: Instrumentation and methodologies are provided that enable the direct measurement of free radicals generated in patients as a result of radiation therapy through the use of proton beams and other forms of ionizing radiation. As a result, in accordance with at least one disclosed embodiment, the instrumentation and methodologies may be used in conjunction with radiation therapy to detect, monitor and/or control generation of free radicals in cancerous tissue during such radiation therapy.

Abstract: Various mechanisms presented in this disclosure provide for dynamically adjusting the exhibition of subtitles. In one example, check-points are introduced into the subtitle file format that, once achieved by a multimedia player, provoke the rescheduling of the moment in which the texts contained in the subtitle file will be exhibited.

Abstract: A phantom calibration body (12) for calibrating diffusion MRI device (16) that mimics a material such as a mammalian tissue is disclosed. The phantom calibration body (12) includes a homogeneous aqueous solution (30) that contains a mixture of low molecular-weight and high molecular-weight polymers housed in a container (14) that is placed in the diffusion MRI device (16) for obtaining one or more diffusion MRI images of the phantom calibration body (12). A measure of diffusivity is calculated for each of the one or more diffusion MRI images in order to calibrate the diffusion MRI device. Methods of using the phantom calibration body (12) to calibrate diffusion MRI device (16) are also disclosed.

Abstract: Systems and methods for coil arrangements in Magnetic Resonance Imaging (MRI) are provided. One coil arrangement includes a magnet bore, a radio-frequency (RF) transmit coil coupled to the magnet bore, and at least one RF receive coil coupled to the magnet bore. The RF receive coil is movable within the magnet bore.

Abstract: A system and method for detecting at least one compound in a material under test (MUT) is presented. The system includes a Nuclear Quadrupole Resonance (NQR) frequency generator that generates an NQR frequency (fNQR) and propagates the fNQR frequency toward the MUT. A microwave frequency generator generates a microwave frequency (fmw) and propagates the fmw frequency toward the MUT. A RF output probe detects radio frequency (RF) emissions returned from the MUT. A detector detects the at least one compound based, at least in part, on whether the RF emissions returned from the MUT include any frequencies corresponding to fmw+/?(n×fNQR), where n is an integer of 2 or greater. In the preferred embodiment, n=2.

Abstract: Disclosed are methods and apparatus using frequency-selected electromagnetic inversion to obtain sub-surface geophysical characteristics. One embodiment relates to a computer-implemented method for inverting an electromagnetic geophysical data signal to obtain an earth response. The method involves computing uncertainties associated with an electromagnetic geophysical data signal and selecting subset of frequencies based on the uncertainties. The electromagnetic geophysical data signal may then be inverted for the subset of the frequencies to determine the earth response. Other embodiments, aspects, and features are also disclosed.

Abstract: In accordance with systems and methods of the present disclosure, an audio device may include an electrical terminal, an audio circuit, and a transducer load detection circuit. The electrical terminal may couple a transducer device to the audio device. The audio circuit may generate an analog audio signal, wherein the analog audio signal is coupled to the electrical terminal. The transducer load detection circuit may detect a load impedance of the transducer device when the transducer device is coupled to the audio device from characteristics measured at the electrical terminal.

Abstract: A method is long observation based selective homonuclear decoupling includes acquiring one of CO or CA time domain signals during rotor synchronized breaks between decoupling pulses.

Abstract: A method for embedded failure detection includes embedding radio frequency identification (RFID) tags at varying depths within a composite material including a polymer, an epoxy or an aggregate bonded with a fluid. Each RFID tag is attached with an insulated wire loop and a sensor and configured to communicate tag identification and resistance on each insulated wire loop upon being energized by an RFID reader. The sensor may be for temperature, moisture, humidity, pressure, light, or acceleration. The RFID tags are read with an RFID reader after initial curing of the composite material for reference information. The RFID reader reads the RFID tags after a particular time period for current information. The current information is compared to the reference information. It is determined whether a change information has occurred for any of the RFID tags to detect a possible failure of the composite material.

Abstract: A rotatable protective cover functioning as a door, that both opens and closes off, an entrance opening of a patient bore in an MRI device is disclosed. The rotatable protective cover comprises a semi-permeable barrier material, MRI shielding, and physical shielding; and is at least partially transparent.

Abstract: In a method for non-selective excitation of nuclear spin signals in an examination subject with a magnetic resonance system, RF excitation pulses are radiated to excite nuclear spin signals in the examination subject with simultaneous switching of gradients for spatial coding of the excited nuclear spin signals, wherein the RF excitation pulses are designed such that the base frequency of a radiated RF excitation pulse is adapted to the simultaneously switched gradient. By the dynamic adaptation of the radiated RF excitation pulses to the respective simultaneously switched gradients, artifacts due to insufficiently excited nuclear spins in an examination region to be examined (in particular even in examination regions that are arranged off-center) are avoided.

Abstract: An audio interface (1) comprising a socket (3) arranged to receive a plug (30), the socket arranged to transfer an audio signal to the plug when connected to the socket, the interface comprising a detector (10) to determine whether an audio signal is received at the socket, the detector arranged to cause generation of a test signal to indicate that an audio signal is received at the socket, at least when the plug is not connected to the socket.

Abstract: A method of using a AFM/NMR probe, the method comprising the steps of injecting a sample to be analyzed with magnetic particles, introducing a probe into proximity with the sample, the probe capable of both transmitting and sensing electromagnetic radiation; generating a magnetic field via the probe, and adjusting the magnitude of the magnetic field to manipulate the magnetic particles within the sample.

Abstract: In a method and magnetic resonance apparatus for automatic calculation of a maximum pulse length of a non-selective excitation pulse for a magnetic resonance data acquisition pulse sequence in which gradients are switched during the radiation of at least one non-selective excitation pulse, a first parameter, which indicates the field of view (FOV) desired in the measurement for which the pulse length of the excitation pulse should be maximized, is loaded into a processor, and a second parameter, which indicates the maximum gradient strength (Gmax) which corresponds to the highest gradient strength applied in the entire measurement, is also loaded into the processor. The processor then calculates the maximum pulse length of the excitation pulse on the basis of the first and second parameter. By the maximization of the pulse length, the SAR exposure is reduced for the examination subject from whom the magnetic resonance data are acquired with the pulse sequence.

Abstract: A cell division tracking apparatus includes a control unit, a search range setting unit, a daughter cell judgment unit. The control unit tracks division processes of the cells based on a cell image group composed of the cell images. The search range setting unit sets a search range to search for daughter cell regions corresponding to daughter cells resulting from a division of a mother cell based on the mother cell region detected by the mother cell detection unit. The daughter cell judgment unit judges whether the cell regions are the daughter cell regions based on a region in which regions of the cell overlap the search range regarding the cell images collected at and after a detection of the mother cell region.

Abstract: A magnetic field measuring device including: a vibrational probe unit having a probe that includes one or more material(s) whose intensity of magnetization is proportionate to an external magnetic field, a mechanical vibration source for the probe; a vibration detector detecting a vibration frequency and amplitude of the probe; an alternating-current magnetic field generator applying to the probe an alternating-current magnetic field; a direct-current external magnetic field generator applying a direct-current external magnetic field to the probe; a frequency modulation detector detecting frequency modulation occurring to the mechanical vibration of the probe; a direct-current external magnetic field controller adjusting the intensity of the direct-current external magnetic field applied to the probe; and a direct-current magnetic field determination unit determining a value of the direct-current magnetic field originating from a specimen.

Abstract: A system and method for detecting at least one material under test (MUT) is presented. A Nuclear Quadrupole Resonance (NQR) measurement system includes a waveform generator configured to generate a continuous wave (CW) input signal comprising one or more frequencies. An RF shielded chamber receives the at least one MUT that is carried by a person walking through the chamber. A probe within the chamber illuminates the MUT with the CW signal and simultaneously receives possible NQR emissions from the at least one MUT. A bridge circuit is utilized to cancel the strong excitation CW signal from the generator which would otherwise mask the weak NQR emissions from the MUT that are received and detected by the measurement system. A detector can then detect the MUT based, at least in part, on the resonance signal.

Abstract: Systems for controlled resonance in electrical power devices are described. A programmed signal processor generates output control signals from input electrical signals based on resonant control parameters for a target power device. Analog electrical control systems for controlled resonance, power devices incorporating controlled resonance, and opto-programmed controllers for use in controlled resonance applications are described, with example embodiments for electro-mechanical systems with resonant constructive power drive action for electric motors.

Abstract: Methods are described for wettability characterization based on NMR measurements, which are sensitive to the surface wetting conditions of oil and water at the pore scale. The described methods make use of surface relaxation effects on the NMR relaxation (T2). Workflows are described to obtain wettability profiles of a porous media such as a rock either in the native state or prepared to a certain state in the laboratory. An underlying forward model is also described for the mixed wet and fractionally saturated pore spectrum. Outputs of the described inversion include continuous saturation and wettability profiles as a function of the pore sizes in the porous media, as well as an averaged value for saturation and wettability over the entire pore spectrum.

Abstract: The various embodiments herein provide an improved system for communicating data over a wired connection. The system comprising a transmitting end, a switching circuit provided at the transmitting end to generate a propagating signal disturbance according to an input signal data received from a source network, a receiving end and a receiver circuit provided at the receiving end to detect the propagating signal disturbance and to regenerate the transmitted signal data from the received signal. The propagated signal disturbance is detected at the receiving end without a need for a common ground reference. The propagating disturbance is created by inducing an electron distribution change at one end of the wired connection and propagated along the length of the wire. The propagating disturbance is generated using one of an inductor, a capacitor and a switching device.

Abstract: Certain implementations of the disclosed technology include systems and methods for an enhanced speech recognition interface. According to an example implementation, a method includes outputting a first icon and second icon for presentation on a display device; responsive to receiving an indication of an input object being maintained at a first location of an input device, causing a recording device to record an audio signal; responsive to receiving an indication that the input object has moved across the input device from the first location of the input device to a second location of the input device, causing the recording device to stop recording the audio signal; outputting text, based on the recorded audio signal, for presentation on the display device; and responsive to receiving an indication of the input object being maintained at the second location of the input device, causing a portion of the text to be removed from presentation on the display device.

Abstract: A method of measuring precessing magnetization includes providing a first site characterized by a first spin order and providing a second site. The method also includes transferring a portion of the first spin order from the first site to the second site. The second site is characterized by a second spin order orthogonal to the first spin order. The method further includes exposing a sample including the first site and the second site to a magnetic field, measuring a precessing magnetization of at least one of the first site or the second site, repeating the transferring a portion of the first spin order from the first site to the second site, and repeating the measuring of the precessing magnetization.

Abstract: A method for predicting the properties of crude oils by the application of neural networks articulated in phases and characterized by determining the T2 NMR relaxation curve of an unknown crude oil and converting it to a logarithmic relaxation curve; selecting the values of the logarithmic relaxation curve lying on a characterization grid; entering the selected values as input data for a multilayer neural network of the back propagation type, trained and optimized by means of genetic algorithms; predicting, by means of the trained and optimized neural network, the physico-chemical factors of the unknown crude oil. The method comprises a training and optimization process of the multilayer neural network of the back propagation type. The method thus defined allows the most representative physico-chemical factors of crude oils to be predicted rapidly and without onerous laboratory structures, or alternatively the distillation curve of crude oils with an acceptable approximation degree.

Abstract: Provided is a total electrical nuclear-spin polarization device that is applicable to many narrow-gap semiconductor two-dimensional quantum structures such as InSb with a large g-factor and with a mobility having a normal value. A nuclear-spin polarization device 1 creates a state where the Landau-level separation and the Zeeman-level separation in a sample are equal to each other in a magnetic field, thereby crossing different spin states, and detects nuclear-spin polarization from a resistance change at the crossing point caused by the nuclear-spin polarization.

Abstract: A device for power measurement for the purposes of plausibility checking and/or calibration of a primary power measurement device on a power amplifier of a magnetic resonance device is provided. The device includes a circulator arranged between an output of the power amplifier and a switching device for connection of the power amplifier to a transmit antenna. A first input of the circulator is connected to the output of the power amplifier, a second input of the circulator is connected to the switching device, and a third input of the circulator is connected to a secondary power measurement device configured for measurement of a signal reflected on the open switching device or the transmit antenna.

Abstract: Schemes are described to produce quasi-static charge separation, Terahertz radiation, and programmable magnetic field generation using linearly-polarized light in unbiased, transparent insulators. The methods exploit a recently-observed magneto-electric optical nonlinearity that produces intense magnetization in undoped, homogeneous dielectrics. Analysis reveals that strong magnetic effects can be induced at modest optical intensities even with incoherent light. Consequently, efficient solar power conversion is feasible without the semiconductor processing or electron-hole pair generation that is required in conventional photovoltaic cells. Additionally, conditions and techniques are described to generate intense THz radiation in unbiased substrates and large magnetic fields orientated transverse to the direction of propagation of light, without the need for any external permanent magnetic or electromagnetic apparatus.

Abstract: A nonlinear laser scanning microscope for flexible, noninvasive three-dimensional detection comprising a measuring head which is flexibly connected to at least one radiation source by transmission optics and can be freely positioned in space, at least one controllable tilt mirror is arranged for aligning the excitation beam in order to keep the excitation beam concentric to an aperture-limited optical element of the measuring head, a test beam which is coupled out of the excitation beam onto a spatially resolving photodetector for monitoring the center alignment of the test beam as a conjugate position to the target position of the excitation beam and directional stabilizing the excitation beam by a control unit of the tilt mirror depending on a determined deviation.

Abstract: A Nuclear Quadrupole Resonance detection system with features that include: a) slab radiating structure for the transmit path; b) reduced impedance transmit radiator; c) portal-embedded stripline couplers for receive path; d) wideband chirps each encompassing multiple simultaneous resonances; e) chirp sequencing enabling three channel architecture; f) magnetic amplification effect of ferrite-based directional couplers; g) determining position of substance within portal.

Abstract: An embodiment of a method of detecting a J-coupling includes providing a polarized analyte adjacent to a vapor cell of an atomic magnetometer; and measuring one or more J-coupling parameters using the atomic magnetometer. According to an embodiment, measuring the one or more J-coupling parameters includes detecting a magnetic field created by the polarized analyte as the magnetic field evolves under a J-coupling interaction.

Abstract: A probe for scanning a surface of an arbitrarily sized sample in magnetic resonance force microscopy comprising a magnetic sensor having a support element coupled to a magnetic particle, an RF antenna, at least partially circumscribing the magnetic sensor, for emitting an RF magnetic field across a portion of the sample and an optical sensor, positioned proximate the magnetic sensor, for detecting displacement of the support element.

Abstract: A system that uses the nuclear quadrupole resonant effect to detect the presence of materials of interest, such as may be excited by radio frequency fields generated within a portal. Transmitted chirp signals may be processed using matching filtering and other signal processing to accurately detect the presence of such materials.

Abstract: Technologies are described herein for noise adaptive training to achieve robust automatic speech recognition. Through the use of these technologies, a noise adaptive training (NAT) approach may use both clean and corrupted speech for training. The NAT approach may normalize the environmental distortion as part of the model training. A set of underlying “pseudo-clean” model parameters may be estimated directly. This may be done without point estimation of clean speech features as an intermediate step. The pseudo-clean model parameters learned from the NAT technique may be used with a Vector Taylor Series (VTS) adaptation. Such adaptation may support decoding noisy utterances during the operating phase of a automatic voice recognition system.

Abstract: A power feeding apparatus, power receiving apparatus, wireless power feeding system, and method for wireless transfer of power are provided. The power feeding apparatus includes an impedance detector, a controller, a power transmitter, a variable matching circuit, and a signal transmitter. The controller is configured to provide first control information and second control information based on an impedance detected by the impedance detector. The power feeding apparatus' variable matching circuit is configured to change a variable diameter of a power feeding coil according to the first control information. The power receiving apparatus includes a power receiver, a signal receiver, and a variable matching circuit. The power receiving apparatus'variable matching circuit is configured to change a variable diameter of a power feeding coil according to the second control information provided by the power feeding apparatus.

Abstract: A sensor comprising: a dielectric waveguide for guiding a microwave signal; and a dielectric reflector at an end of the dielectric waveguide to cause formation of a sensing field beyond an outer surface of the dielectric reflector.

Abstract: A phantom for a medical imaging system with a matrix of spherical hollow elements is provided, with adjacent ones of the elements of a same row being interconnected by and in fluid communication through a hollow tube extending therebetween, with each element being filled with a contrasting solution. Also, a phantom is provided having a plurality of groups of interconnected hollow elements received within a sealed enclosure with the elements of a same one of the groups being in fluid communication with one another and the elements of different ones of the groups being sealed from one another, and the elements of at least one of the groups being filled with a fluid more contrasting than the fluid filling the elements of at least another one of the groups. A method of correcting patient images is also provided.

Abstract: A phantom for an MRI system is provided. The phantom includes a third layer, the third layer including a first structure and a second structure, the first structure including two adjacent wedge-shaped objects in opposite directions which do not generate magnetic resonance signals, the second structure includes a first module group pair, the first module group pair including a first module group and a second module group, the first module group and the second module group each including multiple modules which are identical to each other, aligned with each other and separated from each other by the same distance, and the first module group and the second module group are perpendicular to each other. The phantom for an MRI system can satisfy measurement of multiple image quality indices such as layer thickness and resolution at the same time, which saves a large amount of repetitive work and time.

Abstract: In a method for optimization of a flow coding with switching of an additional bipolar dephasing gradient pair, used in a magnetic resonance (MR) phase contrast angiography, the strength of the flow coding is selected depending on the flow velocity in the vessels that should be depicted. MR signals of an examination region are acquired with continuously running overview measurements, with an operator-selected flow coding strength. After the selected flow coding strength is adopted automatically for the next measurement of the continuously running overview measurements, and two partial measurements with different flow codings are implemented for each selected strength and a phase difference image from the two partial measurements is calculated and depicted in real time, and the selected flow coding strength is automatically adopted for the MR phase contrast angiography.

Abstract: A method for diagnosing certain types of cancers provides a nanoparticle agent to be uptaken by cancer cells for diagnosis and treatment of certain cancers. A compound containing nanoparticles is directed toward a tumor site, and then a predetermined time period passes to allow the nanoparticles to be uptaken by the cancer cells. Imaging is then performed on the nanoparticles by an appropriate imaging device to determine the concentration of nanoparticles uptaken by the cancer cells. Finally, image data provided by the imaging device is analyzed to determine the concentration of nanoparticles and thereby determine whether a tumor is present. The nanoparticle agent can further be employed as a treatment of certain cancers. After the uptake of nanoparticles into the cells, a predetermined field applied to the nanoparticles for a sufficient period of time activates the magnetic cores of the nanoparticles to include hyperthermia-mediated destruction of the cancer cells.

Abstract: A contraband detection system is provided. The contraband detection system includes an X-ray system including a front X-ray transmitter/detector and a rear X-ray transmitter/detector. The contraband detection system further includes a quadrupole resonance (QR) system comprising a first QR coil, and a second QR coil, wherein the first and second QR coils are located between the front and rear X-ray transmitter/detectors, and wherein the first and second QR coils are constructed from a material having a low mass attenuation coefficient and a high conductivity such that the first and second QR coils do not substantially interfere with transmitting X-rays and detecting emitted photons using the X-ray system. The contraband detection system further comprise a computing device coupled to the X-ray system and the QR system, the computing device configured to detect contraband based on signals received from the X-ray system and the QR system.

Abstract: Nuclear quadrupole resonance measurement using two or more wire loop(s) within a space to define a portal, and driving the wire loop(s) with a baseband digital transmitter generating a chirped or stepped signal, to create a corresponding varying electromagnetic field within the portal. Coherent emissions reflected thereby are detected through a directional coupler feeding the transceiver. The detected coherent emissions are processed with a matched filter to determine presence of a target object within the portal.