3860 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.

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.

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.

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.

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.

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.