181 results about "Sensitivity distribution" patented technology

A method is provided that includes defining a plurality of independent component markets for a good. In accordance with the method, each component market can be defined a respective price sensitivity distribution of a unit purchase of the good, as well as a market potential distribution of a number of units of the good. The demand and/or supply in the aggregate market can thus then be modeled based upon the price sensitivity distributions and market potential distributions of the component markets. The method can further include modeling cost and/or profitability of the good in an aggregate market. Profitability can be modeled based upon the demand model and the cost model for the aggregate market.

A data correction apparatus includes a sensitivity correction unit and an SNR distribution correcting unit. The sensitivity correction unit produces first processed data by performing sensitivity correction to first objective data obtained based on correction objective data using ununiform sensitivity distribution of a sensor for acquiring the correction objective data. The SNR distribution correcting unit produces pieces of component data each subjected to corresponding weighting depending on an SNR distribution and corresponding filtering having a mutually different intensity using second objective data obtained based on the correction objective data to produce second processed data by compounding the pieces of the component data.

A sensitivity distribution is estimated for a multicoil used in multicoil fast imaging. Initial sensitivity maps M1 to M3 are produced respectively from images C1 to C3 acquired from the plurality of RF coils in the multicoil. By fitting TPS (thin-plate splines) to the initial sensitivity maps M1 to M3 used as target data, sensitivity maps M1′ to M3′ for unfolding are estimated. In fitting the TPS, functions are activated, such as automatic arrangement of control points, addition of target points to the outside of an image, use of a known model, and fitting to at least either absolute value components of MR data or phase components of the MR data. Thus, even if only coarse echo data is acquired from the region to be imaged, a sensitivity map of each element coil of the multicoil is estimated with high precision.

A method and apparatus is provided for capturing images using a camera or other imager having imaging sensitivity characteristics which vary across the imager's viewing angle. The imager's characteristics can be non-uniform with respect to exposure, color sensitivity, polarization sensitivity, focal distance, and/or any other aspect of image detection. The imager is rotated or translated in order to capture different portions of the scene being imaged. Because the imager is in multiple positions when the respective scene portions are captured, each scene portion is imaged by multiple portions of the imager's sensitivity profile.

A method for homogenizing a static magnetic field with a magnetic field distribution B0(r) for nuclear magnetic resonance spectroscopy by adjusting the currents C_i through the shim coils, thus creating spatial field distributions C_i·S_i(r), where r stands for one, two, or three of the spatial dimensions x, y, and z, and said magnetic field distribution B0(r) has only a field component along z, in a working volume of a magnetic resonance apparatus with one or more radio frequency (=RF) coils (5) for inducing RF pulses and receiving RF signals within a working volume, said RF coils having a spatial sensitivity distribution of magnitudes B1_k(r), and with shim coils (6) for homogenizing the magnetic field within the working volume, said shim coils (6) being characterized by their magnetic field distributions per unit current S_i(r) and having components only along z, includes the following steps:

• • (a) Mapping the magnetic field distribution B0(r) of the main magnetic field,
  • (b) calculating a simulated spectrum I_S(f) based on the sum of the magnetic field distribution B0(r) and the additional field distributions C_i·S_i(r) generated by the shim coils (6), and on the sensitivity distributions B1_k(r) of the RF coils(5),
  • (c) optimising a quality criterion derived from the simulated spectrum I_S(f) by using an optimisation procedure within a search range with the shim currents C_i as a set of parameters, whereby for each new set of parameter values step (b) has to be repeated,
  • (d) realising the found optimum of the quality criterion of step (c) by generating the associated target field distribution B0_T(r).

In this way a direct one-to-one link is obtained between a set of shim currents and the associated NMR spectrum The quality of the desired NMR spectra can be improved with this method.

The invention discloses a phase processing method for parallel magnetic resonance imaging. The phase processing method comprises the following steps of performing Fourier inverse transformation on K spacial data acquired by multi-channel coils in the parallel magnetic resonance imaging to obtain amplitudes and phases of all coil images; constructing a reference coil image, and estimating the spatial sensitivity distribution of all the coils in multiple channels; performing two-dimensional Fourier transformation on the spatial sensitivity distribution of the reference coil image, and intercepting an intermediate matrix as a convolution kernel; constructing a K spacial data convolution model, and solving a joint weight W of the coils; obtaining a K spacial value of a virtual coil and performing Fourier inverse transformation to obtain a virtual coil image; unwrapping a phase and removing the phase of the background of the virtual coil image; extracting the phase of a region of interest by using a mask image. According to the phase processing method disclosed by the invention, phase information of the image is acquired by combining K space with coil data, and the phenomenon that a phase information acquisition algorithm based on an image domain is influenced by noise and aliasing artifact in the reconstruction of the parallel magnetic resonance imaging under the condition of accelerated sampling is avoided.

This invention provides a technique which allows more faithful color reproduction by a relative simple arrangement. To this end, according to this invention, by time-divisionally driving R, G, B, and E LEDs respectively having dominant emission wavelengths of 630 nm, 525 nm, 470 nm, and 500 nm, a common monochrome line image sensor (102) scans a document image. Scanned image data of respective color components undergo correction equivalent to that attained by shifting the barycentric positions of respective wavelength distributions so as to become closer to the CIE-RGB sensitivity distributions.

A magnetic resonance imaging method employs sub-sampled signal acquisition from a number of receiver coils such as surface coils. A full field-of-view magnetic resonance image is reconstructed on the basis of the sensitivity profiles of the receiver coils, for example on the basis of the SENSE technique. The reconstruction is carried out mathematically as an optimization, for example, requiring a minimum noise level in the magnetic resonance image. According to the invention, a priori information is also involved in the reconstruction and the a priori information is taken into account especially as a constraint in said optimization.

In a K-space SENSitivity Encoding (KSENSE) magnetic resonance parallel imaging method the sensitivity distribution of MR reception coils; is calculated and based on the sensitivity of the coils, signals from the respective coil merging channels are merged. The merged data are used to perform k-space data fitting and optimal fitting parameters are found. The fitting parameters are used to remove artifacts in the reconstructed image. The KSENSE method, compared to SENSE, mSENSE and GRAPPA, has the advantages of the image reconstructed by KSENSE having an optimized signal-to-noise ratio (SNR) that is superior to that of an image reconstructed by GRAPPA under the same conditions and approximates that when mSENSE is used, and an image reconstructed by KSENSE has relatively low residual artifacts and an artifact intensity, as a whole, that is superior to that of an image reconstructed by SENSE or the like under the same conditions and equivalent to that when GRAPPA is used, and, compared to GRAPPA that also performs operations in k-space, KSENSE has a higher reconstruction speed.

A method for calibrating coil sensitivity profiles is described. The method includes generating reference sensitivity maps for each coil, imaging a subject, interleaving, with the imaging of the subject, imaging of at least one fiducial mark provided with each coil, and deriving, based on the coil positioning and coil loading, actual sensitivity maps from the reference sensitivity maps.

An MRI apparatus capable of performing a high-speed operation for removing aliasing from the data measured by non-Cartesian imaging in a real space with a small amount of operation is provided. Non-Cartesian data sampling is performed by thinning the number of data by using multiple receiver coils having different sensitivity distribution from each other. Image reconstruction means creates orthogonal data by gridding non-orthogonal data obtained by each receiver coil on a grid having an equal spatial resolution to and a narrower field of view than a target image, subjects it to Fourier transform and creates the first image data containing aliasing components. The second image data is created by using the first image data created for each receiver coil and a sensitivity distribution of each receiver coil.

A magnetic resonance imaging apparatus which executes a scan for allowing an RF coil unit to transmit RF pulses to an imaging area of a subject in a static magnetic filed space and allowing the RF coil unit to acquire magnetic resonance signals generated in the imaging area, includes: a scan section which executes, as the scan, each of an actual scan for acquiring the magnetic resonance signals as actual scan data and a reference scan for acquiring the magnetic resonance signals as reference scan data; an image reconstruction unit which reconstructs an actual scan image about the imaging area, based on the actual scan data and reconstructs a reference scan image about the imaging area, based on the reference scan data; a transmission sensitivity distribution calculating unit which calculates a transmission sensitivity distribution at the transmission of the RF pulses by the RF coil unit in the imaging area, based on the reference scan image and the actual scan image; and an image correcting unit which corrects the actual scan image using the transmission sensitivity distribution, wherein the transmission sensitivity distribution calculating unit includes: a division image generating part which executes image processing for dividing the first reference image by the second reference image, thereby generating a division image; a labeling information generating part which executes a labeling process on the division image thereby to generate labeling information about the division image; a segmentation process executing part which executes a segmentation process on the actual scan image, based on the labeling information thereby to extract a plurality of segments from the actual scan image; and a fitting processing part which calculates relational expressions indicative of relationships between pixel values of pixels constituting the segments and pixel positions thereof with respect to the segments extracted from the actual scan image, by performing a process for fitting to polynomial models, and wherein the transmission sensitivity distribution is calculated based on the relational expressions calculated by the fitting processing part.

To determine the direction of incidence for a signal from an acoustic signal source using a directional microphone system, which has at least two microphones, two or more directional microphone signals are produced, each having a direction-dependent sensitivity distribution with a minimum in one direction. The directional microphone signals are assessed with regard to a quantity to determine the directional microphone signal which is most influenced by the associated direction dependent sensitivity distribution. The direction of incidence is determined as being the direction in which the minimum of the sensitivity distribution of this directional microphone signal is located.

A capacitive sensor for measuring flow parameters of a two-phase flow, a device for measuring phase concentration of a two-phase flow, and a system and method for measuring flow parameters of a two-phase flow is disclosed. In the capacitive sensor, at least one pair of electrodes is twisted by 180° in a common direction into a spiral shape. Edge guard electrodes are twisted in the common direction and are formed between adjacent electrode edges. Problems of non-homogeneous sensitivity distribution of a measuring field and soft field effect can be effectively addressed, thereby allowing reliable and accurate measurement of phase concentration of a two-phase flow. The system for measuring flow parameters of the two-phase flow can output signals with a current of 4˜20 mA to a PLC system or communicate with an industrial process control computer or with a remote control computer system in a operating room.

A general framework is for signal encoding in MRF that enables simultaneous transmit and receive encoding to accelerate the acquistion process, or improve the fidelity of the final image/parameter-map per unit scan time. The proposed method and systems capitalize on the distinct spatial variations in the sensitivity profile of each transmit-coil to reduce the acquistion time, and/or improve the fidelity of the final parameter-map per unit time.

B1 distribution is calculated in a short time with a high degree of precision, and a high quality image is obtained. In the RF shimming for irradiating electromagnetic waves using an RF coil having multiple channels, the absolute values of subtraction images between multiple reconstructed images are used to calculate a transmitting sensitivity distribution which is necessary for calculating inter-channel phase difference and amplitude ratio of RF pulses provided to the respective channels. Those multiple reconstructed images are obtained by executing the imaging sequence after applying a prepulse at different flip angles respectively. Assuming an image obtained with a minimum flip angle as a reference image, for instance, the subtraction images are created between the reference image and the other respective images. It is also possible that multiple subtraction images being obtained are divided by one another, and the transmitting sensitivity distribution is created on the basis of the division result.

In a method of magnetic resonance imaging, a set of nonlinear, mutually orthogonal magnetic gradient encoding fields are sequentially and separately generated in an imaging region [100]. Using multiple receiver coils having nonuniform sensitivity profiles, echo data representing signal intensities in the imaging region is sequentially acquired as the magnetic gradient encoding fields are sequentially generated [102]. A reconstructed image of the imaging region is computed from the acquired echo data [104], and the reconstructed image is then be stored and/or displayed on a display monitor [106].

A photosensor system performs a sensitivity-adjusting reading operation with respect to a subject image, while simultaneously changing the image reading sensitivity stepwise for each of rows of a photosensor array or for specific rows thereof. The dynamic ranges of the lightness data on the read subject image are checked to see how they are distributed in relation to the image reading sensitivities. On the basis of this distribution, an image reading sensitivity that contributes to an optimal image reading state is extracted as an optimal image reading sensitivity.