97 results about "Coefficient quantization" patented technology

A voice encoding/decoding method and apparatus. A voice encoder includes: a quantization selection unit generating a quantization selection signal; and a quantization unit extracting a linear prediction coding (LPC) coefficient from an input signal, converting the extracted LPC coefficient into a line spectral frequency (LSF), quantizing the LSF with a first LSF quantization unit or a second LSF quantization unit based on the quantization selection signal, and converting the quantized LSF into a quantized LPC coefficient. The the quantization selection signal selects the first LSF quantization unit or second LSF quantization unit based on characteristics of a synthesized voice signal in previous frames of the input signal.

Techniques are described that can be used to determine parameters of an adaptive Wiener filter to apply to a video region. The following parameters of the Wiener filter may be adjusted: coefficients, coefficient quantization, filter type, filter size, prediction mode, entropy encoding, and number of filter tables. The parameters associated with the lowest rate distortion cost of the encoder are selected for transmission with the encoded video. If not using adaptive Wiener filtering results in a lowest rate distortion cost, then adaptive Wiener filtering is not used for the video region. If using adaptive Wiener filtering results in a lowest rate distortion cost, then the parameters applied by the adaptive Wiener filtering that result in the lowest rate distortion cost are communicated with the filtered video region.

Proposed is a method and apparatus for determining a weighting function for quantizing a linear predictive coding (LPC) coefficient and having a low complexity. The weighting function determination apparatus may convert an LPC coefficient of a mid-subframe of an input signal to one of a immitance spectral frequency (ISF) coefficient and a line spectral frequency (LSF) coefficient, and may determine a weighting function associated with an importance of the ISF coefficient or the LSF coefficient based on the converted ISF coefficient or LSF coefficient.

A concealment method for a lost frame in decoding a video sequence which was compressed with block motion compensation and transform coefficient quantization compares high-frequency content of co-located macroblocks of frames immediately preceding and following a lost frame to decide whether a scene change has occurred and what concealment approach to pursue.

A curved wavelet transform and a related image/video compression system are disclosed. The curved wavelet transform (CWT) is carried out by applying one-dimensional (1-D) wavelet filters along curves, rather than along only horizontal and vertical directions. The image/video compression system includes a curve determination unit, a curved wavelet transform unit, a wavelet coefficient quantization unit, a wavelet coefficient coding unit, and a curve coding unit. The quantization and coding of the wavelet coefficients are related to the curves. In one embodiment, recursive wavelet filters are used for inverse wavelet decomposition. The system provides higher compression capability than conventional wavelet-based image compression systems.

This invention provides a technique of easily encoding image data to generate encoded data having high image quality within a target code amount using a small memory capacity by image encoding processing of performing frequency transform and quantization of each pixel block. A frequency transform unit separates image data into low frequency band data and high frequency band data. A coefficient quantizing unit, coefficient encoder, and code amount controller operate to encode the high frequency band data within a predetermined amount. When the encoding processing of the high frequency band data has ended, the quantization parameter of the low frequency band data is set based on the generated code amount of the high frequency band data. A coefficient quantizing unit, coefficient encoder, code amount detector, and quantization parameter updating unit operate to encode the low frequency band data into codes within a low frequency band target code amount.

A method and apparatus for correcting a beam error is disclosed. One embodiment of the method comprises the steps of selecting beamweight coefficients based on the satellite orbital data, evaluating an effect of quantization of the beamweight coefficients on the beam error, and selecting beamweight coefficients based at least in part upon the evaluation of the effect of beamweight coefficient quantization on beam error. One embodiment of the apparatus comprises a beamweight correction module for selecting beamweight coefficients based on satellite orbital data, for evaluating the effect of quantization of the beamweight coefficients on beam error, and for selecting beamweight coefficients based at least in part upon the evaluation of the effect of beamweight coefficient quantization on beam error. The beamweight correction module comprises a beamweight generator and a beamweight quantizer for quantizing beamweights from the beamweight generator.

An RF transmitter filter for use in a wireless communication system is disclosed. The filter includes a waveform detector to detect a power level of a transmitted data stream on a symbol-by-symbol basis. The filter also includes a processor to select a combination of filter parameter values according to the power level. The RF transmitter filter selects and adjusts filter parameters (i.e., number of taps or filter length, word length, coefficient quantization, sampling rate, tap delay, sampling bits, etc.) based on signal waveform characteristics. The adjustments limit the transmitted bandwidth and allow transmitted signals to meet an emission mask, while still enabling a receiver to recover the correct sample values of transmitted symbols. The filter further includes a reconfigurable digital filter to filter the transmitted data stream according to the combination of filter parameters.

Provided is a residual signal coding/decoding apparatus and method. The residual signal coding apparatus includes a transformer, an LPC coefficient extractor, an LPC coefficient quantizer, an LP analysis filter, a band splitter, a pulse searcher, and a pulse quantizer. The transformer transforms time-domain residual signals into a frequency domain to output transform coefficients. The LPC coefficient extractor extracts LPC coefficients from the transform coefficients. The LPC coefficient quantizer quantizes the LPC coefficients to output quantized LPC coefficients and corresponding indices. The LP analysis filter performs an LP analysis on the transform coefficients to output LP residual transform coefficients. The band splitter splits the LP residual transform coefficients into bands to output the LP residual transform coefficients. The pulse searcher searches the LP residual transform coefficients for the respective bands to select optimal pulses and output parameters of the optimal pulses. The pulse quantizer quantizes the parameters of the optimal pulses.

The invention discloses a method for carrying out identification by extracting the textural property of iris. The method of the invention comprises the steps that two-dimension wavelet packet decomposition is carried out to an iris image after normalization treatment; quantization coding is carried out to subgraph coefficients, meanwhile, the airspace and frequency domain information of texture is extracted, and finally, Manhattan Distance is used as a classifier to obtain the result of identification. By adopting the iris recognition algorithm provided by the invention, higher rate of accuracy of identification and better noise-resistant performance can be obtained, furthermore, running speed is faster, thus meeting the requirement of real-time performance of a system.

The invention discloses a method for judging the quality of an image. The image is subjected to multilayer wavelet decomposition and each layer of high-frequency sub-band HH(n) is subjected to band-pass analysis, so the quality of the image can be effectively distinguished. The whole image quality evaluation is divided into the following five processing links of: performing wavelet decomposition on a two-dimensional image; quantizing high-frequency wavelet coefficients; counting histograms of wavelet quantization coefficients; calculating image quality evaluation coefficients; and grading the quality of the image. A reference image does not need to be introduced in the process of evaluating the quality of the image, so application is more convenient; and the selection of a grading threshold value is independent of the content of the image, grading characteristic is stable and adaptability is higher.

MIMO transceiver with a reconfigurable pooled digital filter is disclosed. A processor sets parameters of the filter to minimize the number of instructions per second and the amount of power required by the filter to perform, while matching the filter to at least one of: a transmitter filter and a receiver filter. The processor uses an algorithm or a lookup table stored in memory to select the combination of filter parameters. The parameters may be selected from at least one of: a number of taps, a filter length, a word length, a coefficient quantization, a sampling rate, bits per sample, a sampling bit, a tap delay and a coefficient length. After selecting a combination of filter parameters, the processor sends a control signal to the adaptive filter. The pooled adaptive filter reconfigures itself in accordance with the selected filter parameters.

MIMO transmitter with a reconfigurable pooled digital filter is disclosed. A processor uses the output of an envelope detector to set parameters of the filter to minimize the number of instructions per second and the amount of power required by the filter to perform. The processor uses an algorithm or a lookup table stored in memory to select the combination of filter parameters. The parameters may be selected from at least one of: a number of taps, a filter length, a word length, a coefficient quantization, a sampling rate, bits per sample, a sampling bit, a tap delay and a coefficient length. After selecting a combination of filter parameters, the processor sends a control signal to the adaptive filter. The pooled adaptive filter reconfigures itself in accordance with the selected filter parameters.

The present disclosure relates to an image processing device and a method capable of suppressing the reduction of an image quality due to encoding/decoding. The image processing device includes: a quantization unit that when orthogonal transform processing is skipped with respect to a current block, quantizes all components of the current block using one weighting coefficient and when the orthogonal transform processing is performed on the current block, quantizes each component of the current block using a quantization matrix; an encoding unit that encodes the coefficient of the current block which is quantized by the quantization unit; and a transmission unit that transmits the coded data of the current block which is obtained by being encoded by the encoding unit. The present disclosure can be applied to, for example, an image processing device.

The present invention relates to a channel state transmission method using time domain coefficient quantization. A terminal measures channel information in the time domain and transmits it to a base station. In this instance, a multipath frequency selective fading channel is displayed in a tapped delay line format configured with a per-path path delay value and a path gain in the time domain, differentiates a quantization level for each path gain for more efficient transmission, quantizes the same, and transmits it to a transmitter. Therefore, while the amount of bandwidths required for transmitting state information from the terminal to the base station is reduced, the base station can efficiently acquire channel state information on the entire bandwidths. Also, the base station transmits signals to many terminals through beamforming by using the acquired reliable channel state information, thereby increasing the terminal's signal receiving performance.

The invention discloses a color image blind watermarking method. A color digital image is used as a digital watermark to be inserted in a color host image by utilizing Hessenberg matrix disintegration, and the inserted color image watermark is good in invisibility, so that the requirement for protecting a copyright based on a color image marker can be met. A 4*4 pixel block is disintegrated in a Hessenberg way, the encrypted color image digital watermark information is inserted into a maximum coefficient of the Hessenberg matrix by utilizing a coefficient quantization technology, the original host image or the original watermark image is not needed when the watermark is extracted, and a blind detection object can be realized. The method is good in watermark algorithm performance and suitable for the copyright protection adopting the color digital image as the digital watermark.

An orthogonal frequency division multiplexing (OFDM)-based synchronization detection apparatus includes an input register that stores data, a shifter that shifts the data from the input register based on the exponent of a quantized correlation coefficient, an adder that sums the shifted data, and a peak detector that determines the peak value from among the summed shifted data. The OFDM-based synchronization detection method involves quantizing correlation coefficients for synchronization detection into 2<n>-level quantized correlation coefficients (n is an integer not less than 0), shifting input data using the 2<n>-level quantized correlation coefficients, and detecting synchronization using a shifting result.

A calibration technique to compensate for the quadrature phase error between the in-phase and quadrature sampling clocks controlling the quadrature bandpass sampling delta-sigma analog-to-digital demodulator (QBS-ADD) is provided. A low-frequency test tone is injected in the feedback path, up-converted to the radio frequency (RF) frequency, and added to the input of the QBS-ADD. The test tone is demodulated by the QBS-ADD into an in-phase signal and a quadrature signal. The in-phase and quadrature signals are converted into the frequency domain by the discrete Fourier transform. The quadrature phase error is quantified based on the complex Fourier complex coefficients; and the phase difference between the in-phase and quadrature sampling clocks is corrected.

A wavelet coefficient quantization method using a human visual model in an image compression process is provided, which is particularly suitable for remote sensing image compression. A wavelet-domain visual quantization model is obtained through experiments based on human visual characteristics, so as to reflect the relation between distortion of wavelet coefficient blocks and human visual characteristics. The model includes a luminance component, a masking component and a frequency component, where the luminance component is calculated by low frequency coefficients after the k^th level wavelet transform, the masking component is calculated by high frequency coefficients of the second and third levels, and the frequency component is calculated by a statistical method. The method may be used in combination with any mainstream wavelet compression method such as EZW, SPIHT or EBCOT.

The invention relates to a video coding code rate control method based on a Rho domain, which pertains to the technical field of multimedia communication; the invention comprises the steps as follows: the bit rate of a group of pictures (GOP) is confirmed according to a given target code rate, and the bit rate distribution of frame-level is further respectively confirmed according to three frames which are an I-frame (Intra-frame frame), a P-frame (unidirectional predictive frame) and a B-frame (bidirectional predictive frame); the characteristic parameters of the previous frames of the same type are checked to predict the slope parameter Theta of a linear code rate model, model interception difference Delta c, the ratio s of motion vector code rate and entropy coding code rate that is quantified by residual coefficient, and zero coefficient proportion Rho that meets the code rate limit is calculated; a Rho-QP mapping table is referred to obtain a quantization parameter (QP) which is used for coding the current video frame. The code rate control method of the invention is simple and practical, and has excellent performance and the original video coding standards.

MIMO receiver with a reconfigurable pooled digital filter is disclosed. A processor sets parameters of the filter to minimize the number of instructions per second and the amount of power required by the filter to perform, while matching the filter to a transmitter filter. The processor uses an algorithm or a lookup table stored in memory to select the combination of filter parameters. The parameters may be selected from at least one of: a number of taps, a filter length, a word length, a coefficient quantization, a sampling rate, bits per sample, a sampling bit, a tap delay and a coefficient length. After selecting a combination of filter parameters, the processor sends a control signal to the adaptive filter. The pooled adaptive filter reconfigures itself in accordance with the selected filter parameters.

The invention discloses a safety communication method for voice information. The hiddenness of communication is guaranteed through a discrete cosine transform domain embedding algorithm based on coefficient quantization. A secret voice is encrypted through a selective chaotic encryption algorithm, and only few key bits in audio frequency are encrypted in the encryption process, so that the encryption efficiency is greatly improved, and the confidentiality of the content in the secret voice is guaranteed. The completeness of the content in the secret voice is judged by calculating and comparing a robust message authentication code of the secret voice. While the hiddenness of voice communication is guaranteed, the confidentiality and the completeness of the voice communication content are ensured, and the safe voice communication is realized.

The invention discloses a half-band filter structure with frequency response weakly correlated with coefficient quantization digit, comprising a pre-filtering module, a multi-channel selector module, an adder module, a multiplier module, and a delay function module. Under the condition of keeping a half-band filter transfer function unchanged, the dependence of the frequency response of the half-band filter on the coefficient quantization digit is reduced. The half-band filter is split into two cascaded sub filters, and the frequency response of one sub filter is independent of coefficient, so that the influence of the frequency response of the whole half-band filter on coefficient perturbation is reduced. Compared with the traditional implementation structure, the coefficient quantization digit required for achieving the same filter performance is smaller, and the operation burden in the process of filtering operation is reduced. Therefore, the power consumption is reduced, hardware resources are saved, and the cost is reduced.