95 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.

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.

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 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.

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.

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.

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 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.