459 results about "Orthogonal transformation" patented technology

An apparatus for embedding information comprises: a blocking step for dividing data to be processed into blocks; an orthogonal transform step for obtaining coefficients by carrying out orthogonal transformation for each block; an embedding coefficient selecting step for determining coefficients in which the watermark-information will be embedded by using a random sequence which is generated by initial value; an information embedding step for sequentially embedding the watermark-information, which has arbitrary length of bits, by quantizing value of said coefficients using a predetermined value for quantization; and an inverse orthogonal transform step for carrying out inverse orthogonal transformation for modified coefficients to form block in which the watermark-information is embedded, as well as combining the divided blocks and reconstructing the original form.

A method for embedding an entire image, audio or video watermark sequence within another image, audio or video data sequence with minimum loss of data quality is presented. The method exploits the de-correlation property of data coefficients in the orthogonal transform domain, similar to the application in data compression through transform coding. The present invention describes the usage of a Discrete Cosine Transform as the embedding domain. However, other orthogonal transforms such as Fourier, Walsh-Hadamard, Haar, Sine and Wavelet can also be used for this operation. A unique key derived adaptively from spatial locations registering the thresholds of the ac transform energies is used to unlock or de-watermark the embedded image or audio sequence. Moreover, an exponential filter has been developed to compress and expand the watermark coefficients prior to the embedding and retrieval process. The method can be used in resolving multimedia copyright protection issues arising on the Internet and in the music industry, such as the inclusion of a company's logo or an artist's recorded voice. The method can also be incorporated as a built-in feature for digital recording devices, such as still and video cameras, as well as more recent devices such as VCD and DVD players. Moreover, the method can be applied to the commercial and service sectors, where security in transmission and reception of private information in terms of speech or image is of the utmost importance.

An image encoding method includes generating a predictive signal and encoding mode information according to each encoding mode from a macroblock signal corresponding to each macroblock, selecting a quantization code table corresponding to each macroblock, generating a predictive error signal for each encoding mode based on the macroblock signal and the predictive signal, subjecting the predictive error signal to orthogonal transformation, quantizing the orthogonal-transformed predictive error signal while changing a quantization parameter for every plural sub-pixel-blocks, using the quantization code table corresponding to the macroblock, encoding quantization transformation coefficient, calculating an encoding cost, selecting one encoding mode based on the encoding cost, selecting one quantization code table based on the encoding cost, and encoding information of an index indicating the selected quantization code table for every frame of the input image signal or every region of the frame.

An image encoding apparatus includes a converter 1 for receiving an image signal, and for converting the image signal of individual blocks to DC components and AC components by orthogonal transformation of the individual blocks of an image frame; a predicted reference value generator 2 for receiving the image signal, and for generating a predicted reference value of each image frame from DC components resulting from the orthogonal transformation of left-edge blocks of the image frame; and a differential unit 3 for obtaining difference values between the DC components output from the converter 1 and the predicted reference value generated by the predicted reference value generator 2. The image encoding apparatus outputs a bit stream by quantizing and variable-length encoding the AC components and difference values obtained by the differential unit 3, and by quantizing and variable-length encoding the predicted reference value to be added to a header.

A method for encoding a video image includes: generating a prediction image for each of a plurality of pixel blocks that are divided from an input image into a predetermined size, and generating a prediction residual signal that indicates prediction residual between the prediction image and each of the pixel blocks, for each of a plurality of prediction modes; obtaining an orthogonal transformation coefficient by performing orthogonal transformation to the prediction residual signal corresponding to each of the prediction modes; selecting a target prediction mode from among the prediction modes based on a number of the orthogonal transformation coefficients that become non-zero as a quantization processing is performed; encoding each of the pixel blocks in the target prediction mode respectively selected.

The invention discloses a method for islanding microgrid control and optimization based on rotating coordinate virtual impedance. Aiming to a fact that the actual microgrids have complicated impedance characteristics, the method for islanding microgrid control and optimization based on the rotating coordinate virtual impedance includes utilizing the coordinate rotation orthogonal transformation to design the coordinate rotation virtual impedance, improving the impedance characteristics of the microgrid, compensating errors of power distribution and improving power decoupling performance; establishing a complete small-signal dynamic model of the microgrid, wherein the small-signal dynamic model comprises distributed energy sources, power converters, loads and power grids, and guiding the selection of an optimal value on the basis of the small-signal dynamic analytical method; and simultaneously, providing a theoretical basis for the optimization selection of islanding microgrid control parameters by using the small-signal dynamic analytical method, wherein the islanding microgrid control parameters comprise droop control coefficients of the power distribution, process identifier (PI) parameters of a voltage current feedback controller, feedforward control coefficients and the like. The microgrid after being subjected to optimization design in an islanded operational mode is capable of effectively achieving power decoupling and improving the accuracy of the power distribution, the stability of the system and the dynamic performances.

In a code amount estimating method, when encoding quantized values of coefficients of a larger-sized orthogonal transformation than an orthogonal transformation size assigned to a variable length encoding table, the quantized values are rearranged in a one-dimensional form, so as to obtain run-level sets. The number of groups is computed based on a proportion between an orthogonal transformation area corresponding to the orthogonal transformation size assigned to the variable length encoding table and an orthogonal transformation area for an encoding target. The Run-Level sets are classified into groups having the number of groups. Each Run is divided by the number of groups, and the obtained quotient is set as Run. A code length of each Run-Level set in each group is determined by referring to the variable length encoding table. The amount of generated code is estimated to be the total sum of the code lengths of all groups.

The invention provides a compressed sensing theory-based reconstruction method of a magnetic resonance random sampled K space data image. The reconstruction method applies a contourlet conversion and iterative soft thresholding method to realize reconstruction of a magnetic resonance image. The method comprises the following steps: collecting K space data in a magnetic resonance image scanner according to a preset observation matrix phi to generate a measurement value, and keeping y; acquiring y from a coil of the magnetic resonance image scanner, and transmitting y to a computer; and finallyconstructing a same phi, constructing any orthogonal transformation psi, and recovering from y by adopting a compressed sensing theory-based magnetic resonance random sampled K space data image reconstruction method according to reconstruction. According to the method, scanning time is saved, quick imaging is realized, high-quality reliable image information is provided to medical nuclear magnetic resonance imaging detection, and solid theoretical and practical foundation is established for further development and large-scale popularization and application of the medical imaging detection technology.

A method and apparatus is disclosed herein for performing compression with sparse orthonormal transforms. In one embodiment, the method comprises receiving a block of data; classifying the block of data based on directional structure; selecting one of a plurality of available directional, orthonormal transforms to apply to the block based on results of classifying the block; and applying the selected transform to the block to generate a plurality of coefficients, thereby producing a compressed version of the block.

An image information coding apparatus codes an input image signal in a manner optimized on the basis of the visual characteristics. In quantization, an input image signal is divided into blocks, an orthogonal transform is performed on a block-by-block basis, and resultant orthogonal transform coefficients are quantized. A quantizer includes a weighter for, in the quantization, performing weighting on each component of the orthogonal transform coefficients by means of an addition operation on a parameter specifying one of elements of a series of numbers arranged in accordance with a predetermined rule in correspondence with quantization step sizes.

Digital audio samples are represented as a product of scale factors codes and corresponding quantity codes, sometimes referred to as exponent/mantissa format. To compress audio data, scale factors are organized by sample time and frequency either by filtering or frequency transformation, into a two-dimensional frame. The frame may be decomposed into “tiles” by partition. One or more such scale factor tiles are compressed by transformation by a two-dimensional, orthogonal transformation such as a two dimensional discrete cosine transform. Optional further encoding is applied to reduce redundancy. A decoding method and an encoded machine readable medium complement the method of encoding.

The picture decoding method according to the present invention is a decoding method for decoding coded pictures by inverse quantization and inverse orthogonal transformation, in which a quantization matrix which defines a scaling ratio of a quantization step for each component is multiplied by a multiplier, which is a coefficient for frequency transformation or a quantization step, and also, a result of the multiplication is multiplied by a quantized value, as a process of inverse quantization.

An image processing apparatus includes a size acquiring unit that acquires a block size of an orthogonal transformation from encoded data of an image compressed by performing the orthogonal transformation and quantization for each block; a filter selecting unit that selects a filter for each block, the filter reducing an encoding distortion from each block of a decoded image; and an encoding-distortion reducing unit that reduces an encoding distortion by the filter on all pixels within the block. The filter selecting unit selects the filter so that a strength of the filter strengthens by increasing of the block size, or selects the filter so that the number of taps of the filter decreases by reduction of the block size.

A data compressing method comprises first step in which a data is orthogonally transformed so that an orthogonal transform data is generated. A processing step executed subsequent to the first step is divided into a processing step for an alternate-current component of the orthogonal transform data and a processing step for a direct-current component of the orthogonal transform data. The processing step for the direct-current component includes a second step in which an inverse transform equivalent to a decoding process of the orthogonal transform data is executed on the orthogonal transform data.