3893 results about "Low pass filtering" patented technology

In one embodiment, a directional microphone array having (at least) two microphones generates forward and backward cardioid signals from two (e.g., omnidirectional) microphone signals. An adaptation factor is applied to the backward cardioid signal, and the resulting adjusted backward cardioid signal is subtracted from the forward cardioid signal to generate a (first-order) output audio signal corresponding to a beampattern having no nulls for negative values of the adaptation factor. After low-pass filtering, spatial noise suppression can be applied to the output audio signal. Microphone arrays having one (or more) additional microphones can be designed to generate second- (or higher-) order output audio signals.

A technique to reduce blocking and ringing artifacts in low bit-rate block-based video coding is applied to each reconstructed frame output from the decoder. For each pixel block of a reconstructed frame, its DC value and DC values of the surrounding eight neighbor blocks are exploited to predict AC coefficients which might be lost in the quantization stage in the encoding process. The predicted AC coefficients are used to classify each reconstructed block as either a low-activity or a high-activity block. Low-pass filtering is then adaptively applied according to the classification of the block. Strong low-pass filtering is applied in low-activity blocks where the blocking artifacts are most noticeable, whereas weak low-pass filtering is applied in high-activity blocks where ringing noise as well as blocking artifacts may exist. The adaptive filtering reduces ringing noise as well as blocking artifacts without introducing undesired blur. In low activity blocks, the blocking artifacts are reduced by one dimensional horizontal and vertical low-pass filters which are selectively applied in either the horizontal and / or vertical direction depending on the locations and absolute values of the predicted AC coefficients. In high activity blocks, de-blocking and de-ringing is conducted by a single filter, applied horizontally and / or vertically, which makes the architecture simple.

Digital watermark methods for encoding auxiliary data into a host signal are used to authenticate physical and electronic objects. One such method computes a content specific message dependent on the host signal, encodes the content specific message into a watermark signal, and embeds the watermark in the host signal such that the watermark signal is substantially imperceptible in the host signal. One specific implementation embeds data representing salient features of the host signal into the watermark. For example, for photo IDs, the method embeds the spatial location of salient features of the photo into the watermark. Another implementation computes a semi-sensitive hash of the host signal, such as a low pass filtering of the signal, and embeds the hash into the watermark. The watermark signal may be content dependent by making the watermark key dependent on some attribute of the signal in which the watermark is embedded. Another approach is to make the watermark key dependent on a user or an attribute of the user. Yet another approach is to use multiple watermark components and multiple watermark detection stages that help identify and screen out invalid watermark signals. Another digital watermarking method for authenticating a media object transforms a media signal to a frequency domain comprising an array of frequency coefficients. It selects a first set of frequency coefficients, and alters the selected first set of frequency coefficients so that values of the coefficients in the set correspond to a pattern. The pattern of the media signal is authenticated by comparing a pattern of the values of the frequency coefficients in the set with an expected pattern.

First similarity values along at least four directions are ascertained within a local area containing a target pixel and weighted averaging is performed by adding the pixel values of pixels around the target pixel value to the pixel value of the target pixel, adding weight along a direction having a small first similarity value (along a direction manifesting a high degree of similarity). By incorporating the pixel value level differences among a plurality of pixels on adjacent lines extending adjacent to the target pixel into the first similarity values, it becomes possible to effectively remove jaggies that are difficult to eliminate in the prior art. Furthermore, by making a judgment on degrees of similarity by incorporating color information such as characteristics differences among different color pixels, a more accurate judgment can be made with regard to the image structure to enable very accurate direction-dependent low-pass filtering.

The snore recording device includes a portable housing, a microphone carried by the housing for capturing an audio input signal including snoring, a memory, such as a removable memory, carried by the housing, and processing circuitry carried by the housing and coupled to the microphone and the memory. The processing circuitry is for low pass filtering the audio input signal from the microphone to generate a low pass filtered analog signal, performing analog-to-digital conversion (ADC) on the low pass filtered analog signal to generate an intermediate digital signal, performing a moving average filtering of the intermediate digital signal to generate moving average intensity data, performing a Fast Fourier Transform (FFT) on the intermediate digital signal to generate frequency component data, and storing at least the moving average intensity data and frequency component data in the memory.

A multi-path equalization system for orthogonal frequency division multiplexing communication (OFDM) system includes a first estimator for estimating the channel characteristic using pilot signal. A divider is coupled to the estimator for dividing each sub-carrier with the channel characteristic to get the equalization to the data signal. A de-mapper uses the phase and amplitude correction of the channel estimate to recover the data signals. An improved channel estimation is provided by a repeat channel estimation feedback loop that includes the de-mapper a multiplier, an inverse fast Fourier transform (IFFT), a low pass filter and a fast Fourier transform (FFT). The improved channel estimation is obtained by multiplying at the multiplier the conjugate of the de-mapped data to the input sub-carriers and applying inverse FFT, low pass filtering and FFT to get the new channel estimate. Each sub-carrier is divided with new channel characteristic to get new equalization to the data signal. The channel estimation is repeated until there is convergence. The output is provided after the de-mapper. In the case of channel decoding to improve performance a Viterbi decoder and convolutional encoder is coupled in loop between the de-mapper and the multiplier.

A multi-path equalization system for orthogonal frequency division multiplexing communication (OFDM) system includes a first estimator for estimating the channel characteristic using pilot signal. A divider is coupled to the estimator for dividing each sub-carrier with the channel characteristic to get the equalization to the data signal. A de-mapper uses the phase and amplitude correction of the channel estimate to recover the data signals. An improved channel estimation is provided by a repeat channel estimation feedback loop that includes the de-mapper a multiplier, an inverse fast Fourier transform (IFFT), a low pass filter and a fast Fourier transform (FFT). The improved channel estimation is obtained by multiplying at the multiplier the conjugate of the de-mapped data to the input sub-carriers and applying inverse FFT, low pass filtering and FFT to get the new channel estimate. Each sub-carrier is divided with new channel characteristic to get new equalization to the data signal. The channel estimation is repeated until there is convergence. The output is provided after the de-mapper. In the case of channel decoding to improve performance a Viterbi decoder and convolutional encoder is coupled in loop between the de-mapper and the multiplier.

A read device of a capacitive sensor includes: a signal source supplying an electrical read signal for driving the capacitive sensor; and a discrete-time sense circuit for generating an electrical output signal, correlated to variations of capacitance of the capacitive sensor, in response to variations of the electrical read signal. The device moreover includes: a modulator stage for generating a modulated electrical read signal on the basis of the electrical read signal and supplying the modulated electrical read signal to the capacitive sensor; a demodulator stage, connected to the sense circuit, for demodulating the electrical output signal and generating a demodulated electrical output signal; and a low-pass filtering stage for generating a filtered electrical output signal, on the basis of the modulated electrical output signal.

The invention discloses a model-based anti-shake control method for a motor-driven vehicle, which comprises the following steps of: obtaining a motor torque request, performing integral estimation on the rotating speed of a motor, performing negative feedback estimation on a rotating speed error and resistance torque, and performing low-pass filtering. The problem that an electrically-driven vehicle shakes because the motor shakes is solved. The motor torque request is subjected to torque compensation by a model-based rotating speed feedback control method in a closed loop control mode, so that the problem that the vehicle shakes and vibrates under specific working conditions is solved, and the driving comfort of the vehicle is improved; the problem that the vehicle shakes when a vehicle speed exceeds a vehicle speed interval corresponding to the resonant frequency of a power system under the working conditions of starting and accelerating, low-speed rapid accelerating and low-speed rapid decelerating is solved; and a way for solving the problem that the vehicle shakes on the premise of not sacrificing the power performance and braking performance of the vehicle is provided.

The invention provides a double-microphone speech enhancer, which comprises a double-microphone array module, a delay compensation module, a cepstrum field dereverberation module, a speech enhancement processing module and an output module, wherein the cepstrum field dereverberation module has the effect of dereverberation. The invention also provides a speech enhancement method based on the double-microphone speech enhancer. The invention adopts the cepstrum field dereverberation module to carry out beam formation and low-pass filtering, and can effectively eliminate the affection of room reverberation, and meanwhile, by using a speech enhancement algorithm, background noise can be further suppressed.

The present disclosure relates to a method of improving an IR image comprising capturing a visual image and an IR image of an object, altering a resolution of at least one of said visual image and IR image, high pass filtering said visual image to generate a processed visual image, low pass filtering said IR image to generate a processed IR image, and combining information from said processed visual image and said processed IR image to generate a combined image.

A method and apparatus to generate a stereo sound for two-channel headphones from a multi-channel audio signal reproduced from a recording medium. The method may include generating a direct sound and reflected sounds by delaying one of a plurality of channel signals using a plurality of different delay coefficients, multiplying the generated sounds by predetermined different gain values, dividing the multiplied sounds into left and right channel sounds by reflecting a time difference between two ears of a listener on each of the multiplied sounds, low-pass-filtering the left and right channel sounds by reflecting a level difference between the two ears of the listener on each of the left and right channel sounds, and adding together the low-pass-filtered left channel sounds and the low-pass-filtered right channel sounds, respectively.

A multi-band multi-antenna system and a communication device thereof are provided. The multi-band multi-antenna system includes at least one ground, two antenna units, a coupling conductor line and a grounding conductor line. Both of the two antenna units have at least one conductor portion, a low-pass filtering portion and an extending conductor portion. Each antenna unit generates at least one higher and lower operating bands. The low-pass filtering portion is electrically coupled between the conductor portion and the extending conductor portion, and effectively decreases dependent relationship between the higher and lower operating bands. The coupling conductor line is disposed nearby the two antenna units and has a first coupling portion and a second coupling portion. The grounding conductor line is disposed between the two antenna units and connected to the ground.

A method and an imaging system is described for providing a low noise color image. The method comprises the steps of: exposing an image sensor to visible spectral energy and non-visible spectral energy, said image sensor comprising pixels for obtaining first image data associated with said visible spectral energy and pixels for obtaining second image data associated with said non-visible spectral energy; generating first and second image data; subjecting said first image data to a low-pass filt and said second image data to a high-pass filter; and, forming a color image by adding at least part of the high frequency components of said second image data to at least part of the low frequency components of said first image data.

Ventricular stroke volume variation (SVV) is estimated as a function of the standard deviation of arterial blood pressure value measured over each of at least two cardiac cycles, preferably over each of the cardiac cycles in a computation interval covering a full respiratory cycle. In one embodiment, maximum and minimum standard deviation values are determined over the computation interval. SVV is then estimated proportional to the ratio of the difference between the maximum and minimum standard deviation values and the mean of the standard deviation values. In another embodiment, SVV is then estimated proportional to the ratio of the standard deviation of the standard deviation values and the mean standard deviation over the entire computation interval. A pre-processing arrangement for improving reliability of estimates of more general cardiac or hemodynamic parameters is also disclosed and involves smoothing with an approximating function, and sampling and low-pass filtering at an adjustable rate.

Digital watermark methods for encoding auxiliary data into a host signal are used to authenticate physical and electronic objects. One such method computes a content specific message dependent on the host signal, encodes the content specific message into a watermark signal, and embeds the watermark in the host signal such that the watermark signal is substantially imperceptible in the host signal. One specific implementation embeds data representing salient features of the host signal into the watermark. For example, for photo IDs, the method embeds the spatial location of salient features of the photo into the watermark. Another implementation computes a semi-sensitive hash of the host signal, such as a low pass filtering of the signal, and embeds the hash into the watermark. The watermark signal may be content dependent by making the watermark key dependent on some attribute of the signal in which the watermark is embedded. Another approach is to make the watermark key dependent on a user or an attribute of the user. Yet another approach is to use multiple watermark components and multiple watermark detection stages that help identify and screen out invalid watermark signals. Another digital watermarking method for authenticating a media object transforms a media signal to a frequency domain comprising an array of frequency coefficients. It selects a first set of frequency coefficients, and alters the selected first set of frequency coefficients so that values of the coefficients in the set correspond to a pattern. The pattern of the media signal is authenticated by comparing a pattern of the values of the frequency coefficients in the set with an expected pattern.

An image processing apparatus is provided which offers higher versatility than conventional image processing apparatuses. When an input signal to a spatial filtering block is a monochrome signal that contains Y component only, a selector selects its input terminal and a selector selects its input terminal. Then, a low-pass filter output signal of a programmable spatial filter is inputted to a spatial filter, and a low-pass filter output signal of the spatial filer is inputted to a spatial filter. That is, the programmable spatial filter and the spatial filters are connected in series (in cascade), and the cascade-connected three spatial filters perform filtering operation. In this example, low-pass filters with 5×5 taps are connected in cascade in three stages, which enables low-pass filtering with 13×13 taps.

A dual conversion receiver architecture that converts a radio frequency signal to produce a programmable intermediate frequency whose channel bandwidth and frequency can be changed using variable low-pass filtering to accommodate multiple standards for television and other wireless standards. The dual conversion receiver uses a two stage frequency translation and continual DC offset removal. The dual conversion receiver can be completely implemented on an integrated circuit with no external adjustments.

The invention discloses a fundamental wave and harmonic detection method based on a Nuttall window bimodal interpolation FFT (Fast Fourier Transform): a measured signal is carried out the modulus conversion and the low-pass filter wave processing, the signal is operated adding windows by adopting the low side petal voltage and rapid attenuation speed Nuttall window, the bimodal interpolation arithmetic is used for detecting the fundamental wave and the harmonic in the detected signal. The invention comprises the aspects of: (1) modulus conversion and digital low-pass filter wave; (2) FFT operation based on the Nuttall window; (3) bimodal interpolation and polynomial fitting to solve the fundamental wave and harmonic parameters.

The invention provides a method for determining fatigue state according to electroencephalogram (EEG) which adopts a plurality of electroencephalographs and connecting electrodes for realizing the real time acquisition of electroencephalogram. The method comprises the following steps: running interface programs of a PC and the electroencephalographs; realizing the synchronous acquisition of data by using a VC++ to compile visual interface program of the electroencephalographs under the Windows platform, and displaying EEG waveforms acquired in real-time; pre-processing the acquired data; carrying out the low-pass filtering at 0Hz to 30Hz to the data by an FIR (Finite Impulse Response) filter, so as to eliminate the power frequency noise and external interference; decomposing the filtered EEG waveforms by the blind-source separation method, so as to acquire each component of the mixed signal comprising electro-oculogram (EOG) and left and right brain EEGs; carrying out the fast Fourier transform (FFT) on the left and right brain EEGs, and converting the time-domain signals to the frequency-domain signals; working out the energy of alpha, beta, theta and delta waves in the EEGs and classifying the BP (back propagation) neural network of the multi-layer perceptron. The invention has the characteristics of directness and rapidness.

The invention discloses a measuring method for electrical resistivity of electromagnetic waves while drilling, comprising the following steps: generating an electromagnetic wave power signal with specific frequency; emitting the electromagnetic wave power signal into a ground layer through an emitting antenna coil; receiving two electromagnetic wave power signals including measured ground layer information through two receiving antenna coils so as to generate two paths of electromagnetic wave power signals including the measured ground layer information; carrying out band-pass filtering to the two paths of the electromagnetic wave power signals including the measured ground layer information, and carrying out AD sampling to the two paths of the electromagnetic wave power signals including the measured ground information which is subjected to the band-pass filtering so as to generate two paths of electromagnetic sampling digital signals; carrying out frequency mixing transformation and low-pass filtering to the electromagnetic wave sampling digital signals so as to generate amplitude value information and phase information; generating amplitude value ratio and phase difference according to the amplitude value information and the phase information; and generating an electrical resistivity drawing board of the electromagnetic wave power sinals in a chart inversion method according to the amplitude value ratio and the phase difference. An embodiment of the invention also discloses a measuring device for the electrical resistivity of the electromagnetic waves while drilling.

In a CPAP or positive pressure ventilation system, leak is determined at each instant by a lookback for a time as long as single breath to establish the start of an averaging window over which low-pass filtered values used in the determination of a parameter of a leak model are averaged. A jamming index indicates whether the leak is rapidly changing. To the extent that jamming is high, the leak estimate used progressively changes from that using sliding breath-window averaging to a more robust and faster responding low-pass filter method, and adjustment of ventilatory support based on measures employing estimated respiratory flow is slowed down or stopped.

Embodiments herein include a method, service, apparatus, etc., that automatically generates a coloring book image that includes line drawings defining a small number of color coherent, clearly discriminated, closed regions while preserving the basic semantic properties of the original image. These regions hence can be filled in with colored inks, crayons, paints, etc. The method inputs a color image that can be a photograph, scanned image, etc. The method begins by transforming the color image into a chrominance-luminance space and then performs low pass filtering on the color image that preserves the chrominance edges of the features within the color image. Next, the method segments the color image into the features based on locations of the chrominance edges of the features. Then, the method can merge selected features into other features. After performing any merging, the method identifies the remaining chrominance edges of the features within the image and adds lines along the remaining chrominance edges to form outlines of the features. Then, the method automatically filters out all other data from the image to leave only the outlines and produce a revised image consisting of just the outlines. The revised image of just outlines is then output to the user.

Methods and apparatus for determining leak and respiratory airflow are disclosed. A pressure sensor (34) and a differential pressure sensor (32) have connection with a pneumotach (24) to derive instantaneous mask pressure and airflow respectively. A microcontroller (38) estimates a non-linear conductance of any leak path occurring at a mask (12) as being the low pass filtered instantaneous airflow divided by the low pass filtered square root of the instantaneous pressure. The instantaneous leak flow is then the conductance multiplied by the square root of the instantaneous pressure, and the respiratory airflow is calculated as being the instantaneous airflow minus the instantaneous leak flow. The time constants for the low pass filtering performed by the microcontroller (38) can be dynamically adjusted dependent upon sudden changes in the instantaneous leak flow.

A full-bridge phase-shift converter with an auxiliary zero-voltage-switching circuit includes a full-bridge switching circuit, an isolated transformer, an auxiliary zero-voltage-switching (ZVS) circuit, a full-wave rectifying circuit, and a low-pass filtering circuit. The full-bridge phase-shift converter is used to send energy which is supplied from a DC input voltage to a load. Therefore, an auxiliary inductor of the auxiliary ZVS circuit is provided to reinforce sufficient inductive energy on a leading-edge leg, thus achieving normally zero-voltage-switching operations of the full-bridge phase-shift converter.

The invention discloses a quadrature error closed-loop compensating circuit for a vibrating type silicon micromechanical gyroscope. A gyroscope detection signal enters a synchronous demodulation circuit by diving into two parts after being amplified and filtered: one part of gyroscope detection signal is demodulated through reference signals generated by a phase-locked loop, and after low-pass filtering is performed, an angular velocity signal is obtained; the other part of the gyroscope detection signal is demodulated through the reference signals, which is subjected to phase displacement for 90 degrees, and generated by the phase-locked loop, after low-pass filtering is performed, the voltage amplitude of quadrature error signals in the detection signal is extracted out, and a feedback control voltage is obtained through an integrating circuit; the feedback control voltage passes through a single-double switching circuit and is modulated to the driving frequency through a driving detection capacitance so as to generate a feedback current to compensate quadrature displacement current in the detection shaft direction, and then quadrature error amount in the detection signal is eliminated and finally, the pure angular velocity is obtained. According to the invention, the quadrature error amount in an angular velocity detection loop is eliminated by using the feedback current to compensate the quadrature displacement current in the detection shaft direction of the micromechanical gyroscope, and high-precision closed-loop compensating for the quadrature error of the vibrating type silicon micromechanical gyroscope is achieved.

The invention discloses a reentry vehicle full-order non-singular terminal sliding mode posture control method, relates to a reentry vehicle full-order non-singular terminal sliding mode posture control method based on a robust differentiator, and belongs to the technical field of vehicle control. The method includes the steps: generating the state vector of a vehicle; building a mathematical model of a reentry vehicle; simplifying the model of the reentry vehicle by feedback linearization; giving command information yc=(alpha c, beta c and mu c) T of a progressive tracking system for posture angles alpha, beta and mu of the vehicle when external interference exists in the system and parameters are uncertain; controlling allocation to obtain a rudder reflection angle command delta=(delta e, delta a and delta r) T; inputting the obtained rudder reflection angle command to the vehicle and controlling the posture of the vehicle. Tracking errors can be converged into zero within limited time, singular problems of controller output can be avoided, measuring noise generated by a traditional differentiator is suppressed by estimating error second-order derivatives, and buffeting of control quantity is eliminated by boundary layer and low-pass filtering techniques.