94 results about "Discrete transform" patented technology

Calculate the log frame energy value of each of a pre-determined number n of frames of an input speech signal and apply a matrix transform to the n log frame energy values to form a temporal matrix representing the input speech signal. The matrix transform may be a discrete cosine transform.

A method and apparatus for encoding an image is disclosed. A decomposition circuit comprises a set of pixel filters used to identify picture pixels, background pixels and text pixels of the image. An image encoding circuit comprises a lossy discrete transform encoder for encoding the picture pixels, a constant color lossless encoder for encoding the background pixels, and a discrete color lossless encoder for encoding the text pixels.

An access node of a communication system is configured to generate denoised crosstalk estimates for respective channels of the system and to adjust power levels of signals transmitted over one or more of the channels based on the denoised crosstalk estimates. The access node obtains crosstalk estimates for the respective channels. The access node is configured to convert the crosstalk estimate for a given channel to a discrete transform domain, to substantially eliminate in the discrete transform domain one or more designated portions of the crosstalk estimate for the given channel, and to convert remaining portions of the crosstalk estimate for the given channel back from the discrete transform domain to obtain the corresponding denoised crosstalk estimate for the given channel. The access node may comprise one or more central offices of a DSL communication system.

Computer-implemented method for determining optimal sampling grid during seismic data reconstruction includes: a) constructing an optimization model, via a computing processor, given by min_u∥Su∥₁ s.t. ∥Ru−b∥₂≦σ wherein S is a discrete transform matrix, b is seismic data on an observed grid, u is seismic data on a reconstruction grid, and matrix R is a sampling operator; b) defining mutual coherence as

wherein C is a constant, S is a cardinality of Su, m is proportional to number of seismic traces on the observed grid, and n is proportional to number of seismic traces on the reconstruction grid; c) deriving a mutual coherence proxy, wherein the mutual coherence proxy is a proxy for mutual coherence when S is over-complete and wherein the mutual coherence proxy is exactly the mutual coherence when S is a Fourier transform; and d) determining a sample grid r_*=arg min_r μ(r).

The invention provides an adaptive modulation-demodulation method base on fractional order Fourier transform, aiming at reducing influence caused by feedback time delay specific to an MIMO-OFDM (Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing) adaptive modulation system which has feedback time delay, and enabling the system to have better performance in a fast time-varying channel. The method has the technical scheme that inverse discrete fractional order Fourier transform is used to replace inverse discrete Fourier transform for carrying out subcarrier modulation at a transmitting terminal, discrete fractional order Fourier transform is used to replace discrete Fourier transform for carrying out subcarrier demodulation at a receiving terminal, the optimal fractional order Fourier transform order selection is carried out by channel estimation information fed back to the transmitting terminal by the receiving terminal, the deviation between the current channel state information and the feedback channel state information is reduced and the performance of the system having time delay is enhanced.

A Discrete Fourier Transform watermark for use with digital images/video. A Y component of a Y, U(Cb), V(Cr) digital data stream representing color components of digital video is extracted as the digital data for embedding the watermark. The digital data is then scaled to a standard size. A Discrete Fourier Transform (DFT) is performed on the digital data, and a magnitude domain of the Discrete Fourier Transform is computed. The watermark is embedded into selected frequency bands of the computed magnitude domain of the Discrete Fourier Transform, thereby creating a watermarked magnitude domain. The selected frequency bands comprise one or more middle frequency bands, and the middle frequency bands comprise a band of circular rings of the magnitude domain. An inverse Discrete Fourier Transform is performed on the watermarked magnitude domain to reconstruct the digital data with the embedded watermark.

Backscatter imaging using Hadamard transform masking includes an area x-ray source with alternating, masked, Hadamard transform patterns. The total backscatter signal from a target for each pair of corresponding masks is recorded. The difference in signal strengths for each pair of corresponding masks is a direct measurement of the Hadamard transform coefficient for that mask. An image of the target is formed by performing an inverse discrete Hadamard transform on the complete matrix of coefficients.

A method and system render rasterized data by receiving non-rasterized page description language data and a corresponding transformation matrix representing transformation operations to be performed. The non-rasterized page description language data is rasterizing to create rasterized data. The corresponding transformation matrix is decomposed into a plurality of individual transformation operation matrices and a discrete transformation operation value, from a corresponding individual transformation operation matrix, is generated for each transformation operation to be performed upon the rasterized data. The transformation operations are performed upon the rasterized data based upon the generated discrete transformation operation values.

An improved noise reduction process by wavelet thresholding utilizes a discrete wavelet transform to decompose the image into different resolution levels. A thresholding function is then applied in different resolution levels with different threshold values to eliminate insignificant wavelet coefficients which mainly correspond to the noise in the original image. Finally, an inverse discrete wavelet transform is applied to generate the noise-reduced video image. The threshold values are based on the relationships between the noise standard deviations of different decomposition levels in the wavelet domain and the noise standard deviation of the original image.

A system and method for parallel computation of Discrete Sine and Cosine Transforms. The computing system includes a plurality of interconnected processors and corresponding local memories. An input signal x is received, partitioned into P local vectors x_i, and distributed to the local memories. The preprocessors may calculate a set of coefficients for use in computing the transform. The processors perform a preprocess in parallel on the input signal x to generate an intermediate vector y. The processors then perform a Fast Fourier Transform in parallel on the intermediate vector y, generating a second intermediate vector a. Finally, the processors perform a post-process on the second intermediate vector a, generating a result vector v, the Discrete Transform of signal x. In one embodiment, the method generates the Discrete Sine Transform of the input signal x. In another embodiment, the method generates the Discrete Cosine Transform of the input signal x.

A method of interpolating images using continuous extension functions of inverse discrete transforms is described.

A technique for performing a discrete Fourier transform (DFT) includes storing, in a single-port memory, multiple signal points. A first group of consecutive ones of the multiple signal points are fetched (from a first line of the single-port memory) to a first input register associated with a processor that includes multiple arithmetic units (AUs) that are each configured to perform multiply accumulate (MAC) operations. A second group of consecutive ones of the multiple signal points are then fetched (from a second line of the single-port memory) to a second input register associated with the processor. Selected pairs of the multiple signal points are then loaded (one from each of the first and second input registers for each pair) into the multiple arithmetic units during an initial butterfly stage. Radix-2 butterfly operations are then performed on the selected pairs of the multiple signal points (using the multiple AUs) to provide respective output elements.

A method is provided for improved diagnostics of an internal combustion engine that includes cylinders, a crankshaft, crankshaft rotation angle sensor (CRAS), a vibro-sensor, a logic-mark sensor, each sensor produces respective signals. The method contemplates receiving the signals dividing them into a plurality of idling cycles, determining the crankshaft's position based on stochastic filtration, quasicontinuous representation of the signal, the Kalman filter, a nonlinear stochastic filter, based on CRAS characteristics and quasicontinuous representation, determining the Riesz generator basis function based on technical characteristics of the vibro-sensor, secondary discreeting of the signals with a replacement of argument, discreeting of a reciprocal function, obtaining a discrete wavelet transform, obtaining a continuous wavelet transform, obtaining a discrete wavelet transform of a reciprocal function, and producing output data. Two-dimensional arrays are divided relatively to predetermined indexes in the discrete transforms, an empirical probability distribution function is computed. Further optional diagnostic processing is provided.

The invention discloses a dual encryption based DWT-DCT domain audio public watermarking algorithm. The algorithm comprises a watermark embedding process and a watermark detection process. The watermark embedding process sequentially comprises dual encryption of a binary watermark image, segment treatment on an original voice frequency, DWT and DCT of each segment coefficient, quantization embedding, inversed discrete cosine transform (IDCT) and inversed discrete wavelet transform (IDWT) of a quantization coefficient, reorganization and obtaining of a voice frequency containing watermark information. The watermark detection process sequentially comprises segment treatment on an audio signal to be tested, DWT and DCT of each segment coefficient, summing of watermark reference values at corresponding positions of n watermark coefficient series, reconfiguration of a two-dimensional image, inverted scrambling treatment and obtaining of a restored watermark image. By the aid of the algorithm, the transparency of watermarks is effectively guaranteed, the miss ratio of watermarks is greatly reduced, and the robustness and the accuracy of the watermark detection are improved.

A machine or method used in signal processing transforms involving computation of one or more sums each of one or more products. A first multiplier computes a first product and a first set of intermediate terms. A second multiplier computes a second product using one or more of the terms computed by the first multiplier. Because they share computations, the two multipliers can have lower implementation cost than if they function separately. The invention is particularly useful in signal processing transforms that have fixed weights, such as discrete Fourier transforms, discrete cosine transforms, and pulse-shaping filters. These transforms are multiply-intensive and are used repeatedly in many applications. Implementations of shared multiplication techniques can have reduced chip space, computation time, and power consumption relative to implementations that do not share computation. Depending on the properties of the transform being computed, shared multiplication can exploit constant numbers, variable numbers from limited sets of allowed values, and restrictions on one or both numbers in particular products.

The present invention relates, in general, to a watermarking method resistant to a geometric attack in a wavelet transform domain, and, more particularly, to technology for embedding a watermark in a discrete wavelet transform (DWT) domain, thus extracting autocorrelation (AC) peaks, which play an important part in the estimation of geometric attacks in ACF-based watermarking, and detecting watermarks using the AC peaks even after geometric distortion is applied. In the watermarking method of the present invention, a watermark pattern is embedded in subbands of a Discrete Wavelet Transform (DWT) domain. An Autocorrelation Function (ACF) of a watermark is executed in the domain, thus detecting a watermark required to estimate a geometric attack. A watermark signal is detected using an undecimated wavelet transform so as to compensate for an image shift in the watermark.

An image is easily tampered in certain application occasions, so that the real content of the image is hard to identify. Therefore, the content of the image is identified by means of tamper detection necessarily. The invention provides an image fragile watermarking algorithm capable of realizing accurate positioning of a tampered region based on discrete cosine transform. The method comprises the following steps: performing the discrete cosine transform on an original image in a partitioning way; adjusting the numerical value of the high-frequency coefficient of the image subblock discrete cosine transform to build the linear relationship of the numerical values between the two different discrete cosine transform coefficients of the same subblock; and obtaining a coefficient-adjusted image by means of the discrete cosine transform. When the content is identified, the tamper detection is realized by judging whether the set numerical value linear relation is existed between the two corresponding discrete cosine transform coefficients of each subblock of the tampered image by utilizing the reversibility of the discrete cosine transform, thus tamper detection is realized. The algorithm provided by the invention can be used for accurately positioning the tampered region of the image.

The invention discloses a realization method for fast computation of discrete Fourier transform with non-second power points. The realization method is an improvement obtained by comprehensively using a prime factor decomposition algorithm, a mixed-radix FFT (fast Fourier transform) algorithm and a WFTA (Winograd Fourier transform algorithm) decomposition method, and the sequence of non-second power points is decomposed layer by layer through common factor decomposition and prime factor decomposition. The realization method for fast computation of discrete Fourier transform with non-second power points has the characteristics of less computation, high computation efficiency and small overhead for realization.

The invention discloses the method used to supply the audio signal from the compressing audio code stream, it includes the below steps: the code stream can be conducted the unbinding format to distill the changing modulus and the number of the changing modulus of the every blocks; the gained changing modulus are separated into these blocks: the length of the block is equal to the power of the two, and the length of the block is more length than the times of then the number of the changing modulus of every blocks through the unbinding format; the constant length of the reverse scatter changing is used to process the reverse transform of the changing modulus after the blocking, so the transformed reversely sampling buffer is gained; the time field sampling is distilled from the gained reverse changing sampling buffer; the block through the window changing are folded by the composing window conducting the window changing to the distilled time domain sampling block. Thereinto, the numbers of the received changing modulus can be different each other.

An image processing apparatus supporting both discrete wavelet transform and discrete cosine transform with reduced hardware resources. The image processing apparatus is composed of an input unit receiving a plurality of pixel data, a controlling unit selecting a desired transform from among discrete wavelet transform and discrete cosine transform, and providing a plurality of coefficients depending on the desired transform, and a processing unit which processes the pixel data using the plurality of coefficients to achieve the desired transform.

The invention discloses a design method of a two-dimensional double prototype completely-oversampled DFT (discrete Fourier transform) modulated filter bank. The design of the completely-oversampled DFT modulated filter bank is realized under the condition of near perfect reconstruction. The design problem of two prototype filters is resolved into an unconstrained optimization problem, wherein an objective function is overall distortion of the filter bank, namely, a weighted sum of transmission distortion, aliasing distortion and stopband energy of the prototype filters, and the optimization problem is solved through a double-iteration mechanism according to gradient vectors of the objective function. The computation complexity is remarkably reduced according to equivalent conditions of matrix inversion and a fast algorithm of Toeplitz matrix inversion in single-step iteration. With the adoption of the method, the filter bank with better overall performance can be obtained, the computation complexity is greatly reduced, and the large-scale two-dimensional filter banks can be rapidly designed.

The invention comprises a method for calculating an orthogonal discrete transform on the basis of the DIT method in prescribed intermediate steps with the following steps: the data are read from a memory organized on page-for-page basis; the intermediate step prescribed by the transform is carried out; the resulting data are stored in a buffer memory; and the resulting data are written page-for-page from the buffer memory to the memory organized on a page-for-page basis. Suitable discrete orthogonal transforms are FFT, IFFT, DCT, IDCT and transforms of similar structure.

A fixed-coefficient variable prime length recursive discrete Fourier transform system includes a pre-processing device, a real-part computation device, an imaginary-part computation device and a post-processing device. The pre-processing device receives N digital input signals and performs order permutation operation to generate first and second temporal signals, wherein N is a prime number. The real-part computation device receives the real part of the first and second temporal signals and performs discrete cosine/sine transform to generate third and fourth temporal signals. The imaginary-part computation device receives the imaginary part of the first and second temporal signals and performs discrete cosine/sine transform to generate fifth and sixth temporal signals. The post-processing device receives the third, fourth, fifth and sixth temporal signals to perform order permutation and addition operations for generating N digital output signals, wherein the N digital output signals are the discrete Fourier transform of the N digital signals.

The invention discloses a Fourier transform-based text image deflection correction method. Mainly, an angular deflection value is analyzed from a frequency domain of a text image through discrete Fourier transform, thereby realizing deflection correction of the text image.

The invention discloses a SPEED fast magnetic resonance imaging method based on discrete cosine transform. The SPEED fast magnetic resonance imaging method based on discrete cosine transform mainly includes the steps of k space data collection, zero fill Fourier reestablishment, discrete cosine transform, discrete cosine transform domain double-layer sparse ghost model determining, overlapped ghost separation based on LSE, discrete cosine inverse transformation, registering and summation of a plurality of ghost sub-images and image reconstruction. By means of the SPEED fast magnetic resonance imaging method, discrete cosine transform can be used for SPEED data sparse representation and improve image sparseness, and accordingly quality of a SPEED reconstructed image is improved.

The invention belongs to the field of nuclear detection processing in nuclear technique exploration, in particular to a discrete cosine neural-network fuzzy noise reduction method for nuclear detection data, and aims to effectively reduce noise in gamma spectrum data. The method includes the steps: subjecting spatial data formed by nuclear detection signal data to discrete cosine transform to obtain frequency spectrum data in a discrete cosine domain; subjecting the nuclear detection data to filtering and inverse discrete cosine transform in the discrete cosine domain to obtain primary noise reduction result; establishing a neural network, inputting a sample by using the nuclear detection signal data as nodes in the neural network, and estimating parameters of a membership function in the neutral network by means of least squares back-propagation to obtain final noise reduction result output by the neural network. The method is capable of well recognizing noise signals, network model parameters are regulated and optimized according to noise signal features, the noise in the signal data is reduced effectively, and signal-to-noise ratio of the nuclear detection data is increased greatly.