3037 results about "Magnetic field magnitude" patented technology

A method and apparatus for collecting and processing physical space data used while performing image-guided surgery is disclosed. Physical space data is collected by probing physical surface points of surgically exposed tissue. The physical space data provides three-dimensional (3-D) coordinates for each of the physical surface points. Based on the physical space data collected, point-based registrations used to indicate surgical position in both image space and physical space are determined. In one embodiment, the surface of surgically exposed tissue of a living patient is illuminated with laser light. Light reflected from the illuminated surface of the exposed tissue is received and analyzed. In another embodiment, one or more magnetic fields of known shape and size are established in the proximity of the exposed tissue. Data associated with the strength of the magnetic fields is acquired and analyzed.

A magnetically enhanced convection heat sink comprises a heat sink member for dissipating heat from a heat source. A magnetic source creates a magnetic field concentrated at a first location, the intensity of the magnetic field decreasing from the first location to a second location. The heat sink member is positioned within the magnetic field and in a gas flow path between the first and second locations. Gas, having paramagnetic properties, entering the heat sink at the first location is heated by the heat sink member, and as the gas becomes warmer is displaced by cooler gas causing the warmer gas to move toward the second location as it is further heated by the heat sink.

A new approach for locating an underground line described herein remains accurate in the face of bleedover by including both amplitude and phase from at least two magnetic field strength sensors in the measurement set. A numerical optimization step is introduced to deduce the positions and currents of each of several cables, of which one is the targeted cable and the others are termed bleedover cables. Furthermore, some embodiments of the method accounts for practical problems that exist in the field that relate to reliable estimation of cable positions, like the phase transfer function between transmitter and receiver, the estimation of confidence bounds for each estimate, and the rejection of false positive locates due to the presence of noise and interference.

The invention discloses a human body posture recognition method based on self-adaptive extension Kalman filtering, belonging to the field of body-area networks. The method comprises a model design step and a parameter design step. In the model design step, the angular speed and accelerated speed of the motion of a human body and the peripheral magnetic field intensity are collected by virtue of an inertial sensor through the characteristic that the motion angle of limbs of the human body can be reflected by a quaternion, and posture resolving is carried out based on a self-adaptive extension Kalman filtering method so as to obtain a posture quaternion. In the parameter design step, by utilizing a theoretical analysis and experiment method, a process noise covariance matrix is determined, and the value of a noise covariance matrix, a state initial value and an initial value of a state covariance matrix are measured, so that the continuous iteration of the self-adaptive extension Kalman filtering method can be realized, and the motion posture of the human body is continuously recognized in real time. The human body posture recognition method can be used as a human body posture recognition method in the fields of physical training, medical care, game design and the like.

An electromagnet comprises a pair of magnetic pole 1a and 1b, a return yoke 3, exciting coils 4 and 5, etc. In an interior portion of a magnetic pole, plural spacers 2a-2g are provided putting side by side in a horizontal direction. Each of the spaces 2a-2g is an air layer and a longitudinal cross-section is a substantially rectangular shape and the space has a lengthily extending slit shape in a vertical direction against a paper face in FIG. 1. The plural spaces are mainly arranged toward a right side from a beam orbit center O and an interval formed between adjacent spaces is narrower toward the right side. The electromagnet having a simple magnetic pole structure and a wide effective magnetic field area in a case where a maximum magnetic field strength is increased can be secured.

A position detecting circuit including: a plurality of magnetic field detecting devices discretely disposed for outputting a signal corresponding to a magnetic field strength produced by an oppositely disposed magnetic field generation means; a correction parameter arithmetic section for computing correction parameters for bringing to a predetermined constant value a sum of output from one of the magnetic field detecting devices and an output from another of the magnetic field detecting devices; and a position arithmetic section for computing and outputting a relative position between the magnetic field generation means and the magnetic field detecting devices based on an output difference the between the output from the one magnetic field detecting device and output from the another magnetic field detecting device and the correction parameters.

The invention concerns an arrangement for magnetic field measurement of a measurement object (in particular a gradient coil in a magnetic resonance apparatus) with a magnetic field sensor that is designed to measure a magnetic field of the measurement object and with a measurement mechanism on which the magnetic field sensor is arranged at a first position. The measurement object has detectable reference points that can be used for calibration of a spatial position of a position sensor. The calibrated position sensor is arranged at a second position of the measurement mechanism, such that, with the first position and the second position, a spatial position relative to the measurement object can be associated with each magnetic field strength that is measured by the magnetic field sensor.

Methods and apparatus for vertical chip-on-board sensor packages can comprise a vertical sensor circuit component comprising a first face, a second face, a bottom edge, a top edge, two side edges, input / output (I / O) pads and at least one sensitive direction wherein the I / O pads are arranged near the bottom edge. Such vertical die chip-on-board sensor packages can also comprise one or more horizontal sensor circuit components comprising a top face, a printed circuit board (PCB) mounting face, a vertical sensor circuit component interface edge, two or more other edges, and one or more sensitive directions wherein the vertical sensor circuit component interface edge supports the vertical sensor circuit component along the Z axis and conductively or non-conductively connects to the vertical sensor circuit component. The methods and apparatus provided include a multi-axis magnetometer for measuring the magnetic field intensity along three orthogonal axes comprising one or more magnetic field sensing circuit components mounted by their PCB mounting face to a PCB and a vertical magnetic sensor circuit component mounted to the PCB such that the vertical magnetic sensor circuit component is attached to and supported by the magnetic field sensing circuit component.

The invention relates to a vehicle / vehicle flow detection method based on a three-axis magnetoresistive sensor, comprising the following steps: calibrating or calibrating the three-axis magnetoresistance sensor; obtaining the environmental magnetic field strength when there is no car, and obtaining the magnetic field strength when there is a car passing by; using Kaiser The FIR filter is designed to filter the measured magnetic field strength data to obtain the data sequence; the data sequence is binarized; whether there is a car is judged; when there is no car, interference is judged; when there is a car, interference is judged; the vehicle leaves the judgment; after the vehicle is judged The software forcibly resets the three-axis magnetoresistive sensor. It is characterized in that the method integrates the three-axis magnetic field information, which can fully reflect the disturbance information of the geomagnetic field when the vehicle passes by, the sensor can be placed arbitrarily, and the software reset method can effectively overcome the signal drift of the magnetic resistance sensor generated when the vehicle passes continuously Problems, through the judgment of vehicle entry, interference, and vehicle departure, it can ensure high detection accuracy and strong anti-interference ability. This method is easy to implement and is suitable for vehicle / traffic flow detection on traffic roads, bridges, squares, tunnels, etc. It can also be used in Vehicle detection in the parking lot for intelligent management.

Apparatus and method for varying field strength in a magnetic resonance system while keeping a relatively uniform magnetic field distribution. In an embodiment, a two-pole, generally u-shaped magnet assembly generates a static and uniform magnetic field. The magnet assembly includes two facing magnet poles separated by an air gap. Holes may be formed with the magnet poles. The field control rods may be placed at a pre-determined distance into these holes and symmetrically or asymmetrically moved across each magnet poles in a controlled manner to change the magnetic field strength while keeping the uniform magnetic field distribution. Maximum magnetic field strength may occur when the rods are removed. Minimum magnetic field strength may occur when the rods are fully inserted.

An MRI apparatus includes a filtering control unit that filters discrete MR-signal values. A filter-coefficient setting unit sets a plurality of filter coefficients with respect to each point of sampling time, based on time-shift amounts corresponding to variations in an MR-signal frequency arising from temporal variations in the magnetic field strength. A product-sum operating unit filters the MR-signal values by performing a product-sum operation between the filter coefficients and the MR-signal values. An image-data creating unit creates image data based on the MR-signal values on which the filtering processing is performed.

A magnetic toner including at least: a binder resin; and a magnetic body, in which, when magnetization at a magnetic field strength of 397.9 kA / m and a coercive force of the magnetic toner are denoted by σs (Am2 / kg) and Hc (kA / m), respectively, a magnetic field strength at which the magnetic toner shows a magnetization value equal to 95% of σs is denoted by H95% (kA / m), and a number average particle size of the magnetic body is denoted by d (μm), H95%, Hc, and d satisfy the following expressions.151<H95%<200  (1)7.1<Hc<12  (2)40<Hc / d<150  (3)

A magnetometer is provided comprising an atomic vapor in an enclosure, a source of light for preparing the vapor into a state exhibiting electromagnetically induced transparency, a first laser beam passing through the atomic vapor, a phase detector for detecting changes in phase of the first laser beam, and a controller which controls the light source and laser beam and receives the information detected by the phase detector in order to compute from those changes in phase a magnetic field strength in the presence of a selected background magnetic field of at least 0.001 T. Operation in the presence of a background field helps make this magnetometer suitable for diagnostic imaging applications.

An apparatus is disclosed for Magnetic Resonance Imaging with specialized imaging coils possessing high Signal-to-Noise-Ratios (SNR). Radio Frequency transmitting and / or Radio Frequency receiving elements include carbon nanotube material, a ballistic electrical conductor having a resistance that does not increase significantly with length. The shapes of the receiving and transmitting elements can be linear, curvilinear, or coiled. The carbon nanotube material can be layered. Due to their enhanced SNR properties, preferred embodiments have smaller static magnetic field strengths with imaging quality comparable to known field systems, leading to substantial reductions in system size and cost. Other preferred embodiments provide enhanced imaging with known MRI static magnetic field strengths.