329 results about "Nonlinear filter" patented technology

A system (10) analyzes signals representative of a subject's brain activity in a signal processor (12) for information indicating the subject's current activity state and for predicting a change in the activity state. One preferred embodiment uses a combination of nonlinear filtering methods to perform real-time analysis of the electro-encephalogram (EEG) or electro-corticogram (ECoG) signals from a subject patient for information indicative of or predictive of a seizure, and to complete the needed analysis at least before clinical seizure onset. The preferred system then performs an output task for prevention or abatement of the seizure, or for recording pertinent data.

A method of performing bilateral filtering and using the method for displaying high-dynamic-range images is presented. The method reduces the contrast of the image while preserving detail of the image. The presently disclosed method incorporates a two-scale decomposition of the image into a base layer encoding large-scale variations, and a detail layer. The base layer has its contrast reduced, thereby preserving detail. The base layer is obtained using an edge-preserving bilateral filter. The bilateral filter is a non-linear filter, where the weight of each pixel is computed using a Gaussian in the spatial domain multiplied by an influence function in the intensity domain that decreases the weight of pixels with large intensity differences. The bilateral filtering is accelerated by using a piecewise-linear approximation in the intensity domain and appropriate subsampling.

A system and method are disclosed for a nonlinear filter having a nonlinear transfer function. The nonlinear filter comprises a plurality of linear filters each having a filter output, a plurality of nonlinear elements each connected to one of the plurality of linear filters, and a combination network connected to the plurality of nonlinear elements. The nonlinear elements are used to produce nonlinear effects and generate a plurality of nonlinear outputs, and the combination network combines the nonlinear outputs.

A linearizer and method. In a most general embodiment, the inventive linearizer includes a characterizer coupled to an input to and an output from said circuit for generating a set of coefficients and a predistortion engine responsive to said coefficients for predistorting a signal input to said circuit such that said circuit generates a linearized output in response thereto. In a specific application, the circuit is a power amplifier into which a series of pulses are sent during an linearizer initialization mode of operation. In a specific implementation, the characterizer analyzes finite impulse responses of the amplifier in- response to the initialization pulses and calculates the coefficients for the feedback compensation filter in response thereto. In the preferred embodiment, the impulse responses are averaged with respect to a threshold to provide combined responses. In the illustrative embodiment, the combined responses are Fast Fourier Transformed, reciprocated and then inverse transformed. The data during normal operation is fed back to the data capture, corrected for distortion in the feedback path from the output of the amplifier, converted to basedband, synchronized and used to provide the coefficients for the predistortion linearization engine. As a result, in the best mode, each of the coefficients used in the predistortion linearization engine can be computed by solving the matrix equation HW=S for W, where W is a vector of the weights, S is a vector of predistortion linearization engine outputs, and H is a matrix of PA return path inputs as taught herein.

A baseband signal predistortion processing device and method. Said device includes: a predistorter, for preserving and updating nonlinear filter parameter, carrying out power statistic of input signals, selecting corresponding nonlinear filter parameter according to the power statistical result and predistortion-processing baseband digital signals by use of said corresponding nonlinear filter parameter, and outputting the predistortion processed baseband digital signals; an adaptive parameter calculating unit, for calculating nonlinear filter parameter according to received feedback signals of radio-frequency channel and sampled signals of baseband digital signals, and transmitting the calculating result to the predistorter. Said method can not only solve the nonlinear problem of power amplifier, but also can select different non-linearity inverse model according to different input signal and power amplifier characteristic, and increase whole efficiency of base station transmitter.

The image encoding method includes: encoding an image including a block by performing, in at least one of intra prediction, inter prediction, and an in-loop filter, a non-linear process by which the input-output relationship becomes non-linear; and encoding an operation parameter of a non-linear filter to be used in the non-linear process.

Apparatus for amplifying an input signal having an input signal power includes a power amplifier, which is adapted to amplify an intermediate signal so as to generate an output signal, and which is characterized by a non-linearity. A non-linear filter is coupled to decompose the input signal into a series of input signal components, each such component proportional to a product of the input signal by a respective integer power of the input signal power, and is adapted to filter the signal components responsively to the non-linearity so as to generate the intermediate signal for input to the power amplifier.

Nonlinear optical filters and associated methods. In a representative embodiment, a nonlinear optical filter includes a grating and a dye-doped polymer layer coupled to the grating. The dye-doped polymer layer may include ionic self-assembled layers. An associated method includes: providing a nonlinear filter comprising a grating and a dye-doped polymer layer coupled to the grating, directing an input broadband optical wave upon the filter, and backward diffracting the broadband optical wave from the grating as an output narrowband optical wave. The output narrowband optical wave may include a second harmonic beam.

A method and system for improving a color image separable into three color components. A noise-filtering unit is used to filter the color components for providing noise-filtered color components. The edge information extracted from one color component is used to adjust the noise-filtered color component of a different color. The algorithm for noise filtering of color components can be based on linear spatial filters, non-linear filters or the combinations thereof. The algorithm for edge detection can be based on directional or non-directional spatial filters.

A signal processing technique for RF active, passive, or aided localization approaches that utilizes multipath signals as additional measurements with a filter or estimator, e.g., a nonlinear filter. The filter uses indirect and direct path measurements or any other available signals to build parametric models of observable indirect paths. If one or more direct path measurements are subsequently lost (e.g., due to obstruction), the filter maintains an estimate of the position of the person or object of interest using indirect path measurements.

The invention provides a fuzzy adaptive variational Bayesian unscented Kalman filter method. The method comprises the steps of estimating a one-step prediction target state as shown in the description and a covariance matrix thereof as shown in the description, iteratively estimating the variance as shown in the description of the measured noise, calculating the true value as shown in the description, the estimate value as shown in the description, the matching degree index as shown in the description and the adjustment quantity as shown in the description of a residual variance matrix at the current moment, and the adjusted measured noise variance as shown in the description, and calculating the estimated value as shown in the description of the target state and the error covariance matrix thereof. The method is capable of estimating the statistic variance capacity of the measured noise on line, and therefore, the filter error caused by unknown time variant of the noise statistical property is reduced and nonlinear filter estimation accuracy is improved. Meanwhile, the fuzzy logic method based on the innovated covariance matching technique is used for adjusting the measured noise variance estimated by the variational Bayesian method in real time, inhibiting the divergence of the filter and enhancing the robustness of the filter method.

A method of converting an input analog signal to a compensated digital signal comprises converting the input analog signal to an uncompensated digital signal, inputting the uncompensated digital signal to a distortion model, generating a modeled distortion signal based on the uncompensated digital signal, and subtracting the modeled distortion signal from the uncompensated digital signal to generate the compensated digital signal. A distortion compensating analog to digital converter (ADC) comprises an uncompensated ADC configured to convert an input analog signal to an uncompensated digital signal, and a compensation module coupled to the uncompensated ADC, configured to receive the uncompensated digital signal, generate a modeled distortion signal based on the uncompensated digital signal and subtract the modeled distortion signal from the uncompensated digital signal to generate the compensated digital signal.

A system and method for generating a multidimensional navigation solution utilizes Global Positioning System (GPS) data to obtain highly reliable and accurate navigational solutions in high interference and dynamic environments, at a performance level which has been heretofore unattainable. Additional sensors such as inertial (gyros and accelerometers), altimeters, radars, etc. may be employed in a deeply integrated configuration. The approach taken in the present invention differs from that of previous techniques through its exploitation of nonlinear filtering methods; as a result, the navigation system architecture and processes employed yield significant improvements in navigation system performance, both in code tracking and reacquisition, and in carrier tracking and reacquisition. The improvements are particularly significant at low signal/noise ratios, where conventional approaches are especially susceptible to loss of code lock or carrier lock.

The invention provides a strap-down inertial navigation system/visual odometer integrated navigation method which comprises the following steps: mounting a binocular visual odometer and a fiber-opticgyroscope inertial navigation system on a transporter and collecting data of all sensors; extracting features in an image sequence with an FAST method, completing feature matching with a feature matching method based on random sample consensus and calculating movement information of the transporter; establishing a nonlinear state equation and a measurement equation of a strap-down inertial navigation system/visual odometer integrated navigation system; and completing time update and measurement update of the strap-down inertial navigation system/visual odometer integrated navigation system with a volume Kalman filter of a nonlinear filter, and estimating the state of the system, so as to realize the navigation and location of the strap-down inertial navigation system/visual odometer integrated navigation system. According to the strap-down inertial navigation system/visual odometer integrated navigation method, a feature matching algorithm is optimized, and a nonlinear volume Kalman filter algorithm is utilized, so that the location accuracy and the robustness of the integrated navigation system are improved.

A method and device for implementing a smart antenna in a network that uses a deterministic access protocol, one or more mobile stations MS and at least one base station BS, the transmitted data being included in a data frame, wherein it comprises at least the following steps: On entry into the network:

• • the step of synchronizing a mobile station MS equipped with an FESA directional antenna on a transmission from the base station by changing beam for a duration at least equal to a frame in order to aim the directional beam toward the base station BS to obtain the best signal reception,
  • the step of following the synchronization of the mobile station on the transmission from the base station, and implementing an aiming tracking algorithm in order to retain the best signal reception,
  • the step of determining the parameters for defining the downlink or the uplink by decoding signaling messages contained in the message transmitted by the base station,
  • triggering a network entry procedure.

Once the mobile station MS has entered the network:

the selection of the new beam being based on a mechanism with hysteresis that uses a linear filtering preceded by a hop-based rejection step or that directly uses a nonlinear filter.

A method and apparatus for non-linear prediction filtering are disclosed. In one embodiment, the method comprises performing motion compensation to generate a motion compensated prediction using a block from a previously coded frame, performing non-linear filtering on the motion compensated prediction in the transform domain with a non-linear filter as part of a fractional interpolation process to generate a motion compensated non-linear prediction, subtracting the motion compensated non-linear prediction from a block in a current frame to produce a residual frame, and coding the residual frame.

A territorial waters synthesis pore diameter radar image point target extraction method belongs to the technical field of image processing, which comprises steps below: Calculating point-wise Holder's index of an original image and enhancing two-valued obfuscation; inputting the processing result as an independent composition analysis method to obtain spatial expression of the image, viz. base image and independent composition; formulating separation basis to separate the space, obtain a noise space corresponding to noise signals and a non-noise space corresponding to non-noise signals; using a nonlinear filter operator to enhance the independent composition of the non-noise space and repeatedly restructure the independent composition and the acquired image to restore the original image; cutting two-valued extraction result of the territorial waters original image point target through simple threshold values. The present invention brings proper restriction upon strong ocean noise waves of the territorial waters synthesis pore diameter radar image.

The invention discloses a nonlinear system state estimation method based on Kalman filtering positioning, and proposes a strongly adaptive Kalman filtering mechanism which combines a nonlinear filtering algorithm and Kalman filtering. The method comprises the steps: carrying out the simultaneous estimation of node positions and channel parameters through employing an RSSI state estimation algorithm based on square root volume Kalman filtering, and obtaining the estimation value of a state vector; employing the Kalman filtering for further processing according to the linear change of a state equation, obtaining optimal estimation, and building a strongly adaptive square root volume Kalman filtering algorithm; giving the design steps of the strongly adaptive square root volume Kalman filtering algorithm; and calculating a theoretical square root error lower bound under a state space model based on the RSSI state estimation. The method enables an estimation result to be improved, and improves the precision. The method does not need to excessively depend on improper initial conditions, can be well adapted to a highly nonlinear system, and is not liable to enable the algorithm to be divergent and ineffective.

A method of processing an input signal that includes an input variable is disclosed. The method comprises comparing the input variable to a set of ordered constants, determining the relative location of the input variable within a range of possible inputs and determining a filter coefficient of a nonlinear filter using the relative location of the input variable. A configurable filter comprises an interface configured to receive an input signal that includes an input variable, a nonlinear filter coupled to the interface, configured to process the input signal, and a processor coupled to the nonlinear filter, configured to determine the relative location of the input variable within a range of possible inputs and to determine a filter coefficient of the nonlinear filter using the relative location of the input variable.

There is disclosed a head positioning control system in which when internal vibration including a frequency component different from a frequency of disturbance such as a higher harmonic occurs by a nonlinear element, the system effectively suppresses the internal vibration. The system has a nonlinear filter 11 to generate a higher wave as an input of an adaptive filter for performing feed forward control.