192 results about "Hadamard transform" patented technology

A staring imaging system inputs a 2D spatial image containing multi-frequency spectral information. This image is encoded in one dimension of the image with a cyclic Hadamarid S-matrix. The resulting image is detecting with a spatial 2D detector; and a computer applies a Hadamard transform to recover the encoded image.

A symbol sequence contained in a received signal comprising a cyclic convolution of a Walsh code multiplexed signal and a channel impulse response of a multipath channel is detected using Walsh Hadamard domain equalization techniques. The method comprises converting the received signal and the channel impulse response of the multipath channel from the time domain to the WHT domain, and determining the symbol sequence based on equalizing the received signal in the WHT domain using WHT spectra of the channel impulse response to remove inter-symbol interference from the received signal due to cross-correlation between Walsh codes.

The invention discloses a non-local image denoising method based on low rank restoration. The method comprises the steps of (1) collecting an image, (2) carrying out gray transformation on the collected image, (3) establishing a three-dimensional similarity matrix through the global search of a similar pixel block for the image which is subjected to gray transformation, then carrying out hard threshold filtering on the discrete cosine transform and Hadamard transform coefficients of the three-dimensional matrix is carried out, obtaining the initial estimation of the similar pixel block with the removal of partial noise, and improving the matching accuracy of the similar pixel block with low rank restoration denoising while removing a large part of noise, and (4) with transform domain filtering as prior knowledge, searching a similar pixel block in a search area for an initially denoised reference pixel block, then forming the similarity matrix by using a similarity block corresponding to an original image, carrying out low rank matrix decomposition on the similarity matrix, effectively separating noise and a signal, and obtaining a final denoised image. The method has the advantages of a simple and fast algorithm, a high signal-to-noise ratio and good consistency and is especially suitable for the requirements of high quality noise reduction of large-scale images.

The Hadamard transform is used to spread data within data blocks in a multicarrier MIMO system, before transmission. In this manner, the negative effects caused by the clustering of bad subcarriers (i.e., subcarriers having a low transmission coefficient due to fading) may be reduced. In at least one embodiment, a MAP-type detection scheme is used in the receiver to extract bit reliabilities from the received signals.

The invention discloses a method for embedding a digital watermark in a binary image. The method is as follows: part or all of the binary image is divided into at least two image blocks, and the first pixel is obtained according to the number of black pixels in each image block. A digital sequence; grouping the first digital sequence, performing Hadamard transformation on the data in each group to obtain a second digital sequence corresponding to each group; using a quantization method based on a quantization table, the watermark to be embedded Embedding the signal into the second digital sequence to obtain a third digital sequence; performing an inverse Hadamard transformation on the third digital sequence to obtain a fourth digital sequence, and determining the need to change the color in each image block according to the fourth digital sequence number of pixels, select a corresponding number of pixels in each image block, and change the color of the selected pixels. By adopting the invention, the image embedded with the watermark has a good visual effect and can resist printing, copying and scanning attacks.

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 for decoding received data in a decoder which receives data from an encoder varying a length of a Walsh code according to a coding rate of transmission data, and has maximum IFHT (Inverse Fast Hadamard Transform) stages capable of decoding even the data encoded by a Walsh code with a maximum length. The method comprises selecting at least one IFHT stage among the maximum IFHT stages according to a length of the Walsh code used for the received data; and performing inverse fast Hadamard transform on the received data by the selected IFHT stage.

Interpreting data obtained by analysis of nucleic acids (DNA) by obtaining nucleic acid data in a spatial domain, transforming the nucleic acid data from the spatial domain into a frequency domain, and obtaining sequence data of the nucleic acid data by executing a data mining process on the transformed nucleic acid data. The transformation may be performed by a Hadamard transform, a Fourier transform or a Wavelet transform to obtain frequency coefficients, with less than all of the frequency coefficients being utilized in the data mining process. In addition, the frequency domain data may be normalized prior to the data mining process. The data mining process may be subjecting the frequency coefficients to a connectionist (neural network) algorithm or to a classification tree/rule induction (CART) algorithm.

The invention relates to a Hadamard transform imaging spectrometer, which overcomes the defects that after-treatment workload is large, the enhancement function on a certain characteristic spectral coverage cannot be realized, the coding precision is low, the volume is big and the requirements on processing and debugging are high in the prior art. The Hadamard transform imaging spectrometer comprises a preposed imaging system, a first collimating lens, a light-splitting device, a first convergent lens, a digital micromirror device, a second collimating lens, a light-converging device, a second convergent lens and an image surface detector; the preposed imaging system comprises a preposed imaging lens; the first collimating lens, the light-splitting device, the first convergent lens and the digital micromirror device form a light-splitting modulation system; the second collimating lens, the light-converging device, the second convergent lens and the image surface detector form a light-converging imaging system; and the composition of the first collimating lens is the same as that of the first convergent lens, and the composition of the second collimating lens is the same as that of the second convergent lens. The Hadamard transform imaging spectrometer has the advantages of small volume, high coding precision and the like.

The invention discloses a decision-making method and a decision-making method device for intra-frame prediction modes of high efficiency video coding. The decision-making method comprises the steps of: dividing directivity prediction modes of a current PU block into M direction mode groups according to corresponding serial number of the modes, and adopting a dichotomy to find out an optimal intra-frame prediction mode based on Hadamard transform at minimal rate distortion cost in each direction mode group; carrying out rough mode decision based on Hadamard transform on a mode 0, a mode 1, one or more most-likely prediction modes and the optimal intra-frame prediction mode in each direction mode group, and selecting the N intra-frame prediction modes based on Hadamard transform at minimal rate distortion cost to be added into a screening list; and carrying out rate distortion optimization calculation on the intra-frame prediction modes contained in the screening list, and selecting one of the optimal intra-frame prediction modes for predicting the current PU block. Compared with the prior art, the decision-making method and the decision-making method device can increase the intra-frame prediction encoding speed by 20% without changing video compression quality.

The present invention provides a method and apparatus that transforms input signals X0, X1, X2, X3 using a 4-point Hadamard transform matrix, and of the resulting transformation data, rounds up the LSB of the first transformed data and rounds down the LSB of the remaining odd-numbered data. When restoring the data to its original state the rounding is executed after a Hadamard inverse transformation is performed, thereby restoring the data to its original state X0, X1, X2, X3.

Embodiments of the invention compress ultrasound RF data after the receiver beamformer. An efficient compression algorithm is disclosed that incorporates the use of the Discrete Cosine Transform (DCT) and the Discrete Wavelet Packet (DWP) transform, followed by quantization of the wavelet coefficients. The algorithm first processes ultrasound scanlines from the receiver beamformer using a DCT transform. In a low-power configuration, a Hadamard transform may be used instead of the DCT. The output of the DCT processing is DCT coefficients at different frequencies. An optimized wavelet packet transform is then used for each coefficient line. The wavelet filter kernels and the wavelet packet trees can be jointly optimization using a two-step optimization algorithm.

The invention discloses a quick HEVC (High Efficiency Video Coding) inter-frame prediction mode selection method. After coarse selection of inter-frame prediction modes, the statistical property of Hadamard transform-based cost values corresponding to the coarsely selected inter-frame prediction modes is fully utilized, and the correlation of the video texture direction and an inter-frame prediction mode angle are fully considered; for prediction unit types of different sizes, the inter-frame prediction modes after the coarse selection are quickly screened through a threshold value method or the continuity of the coarsely selected inter-frame prediction modes is calculated to reflect the texture direction of the prediction unit, so that the unnecessary coarsely selected inter-frame prediction mode is screened without introducing more extra calculation; in a verification process of the most possible prediction mode, the correlation of the coarsely selected inter-frame prediction modes and the most possible prediction mode and the space correlation of a video image per se are fully considered, the final optimal inter-frame prediction mode is quickly obtained, and the inter-frame coding complexity is reduced on the premise that the video coding quality is guaranteed.

Blocks in two different frames are subjected to Hadamard transform by first and second Hadamard transform circuits, and a sum component and a difference component are calculated for the components of the two blocks corresponding to each other to perform three-dimensional Hadamard transform, so that detection is made as to whether or not these blocks include a motion. While the sum component and the difference component are encoded for the block determined as including a motion, a motion detection result, rather than the difference component, is encoded for the block determined as including no motion. As a result, a high compression ratio can be achieved in video encoding with a small-scale circuit.

Methods and apparatus for performing near lossless-concatenated N-level constrained quantization Hadamard transform decoding are provided. Accordingly, the present invention provides a transform-based coding technique, where the coding loss introduced during repeated encoding and decoding is reduced to a substantially insignificant level. This is accomplished by employing a constrained quantization and inverse quantization operation in each level of encoding/decoding in the decoder. In this manner, the concatenation error between each level of a decoder is reduced to a substantially minimum level and the quantization error introduced during quantization operations, i.e., originally at the encoder and in each level of the decoder, is substantially reduced. Thus, the decoded bit stream that is output at the N-th level of the decoder is substantially the same as the original bit stream provided to the input of the encoder.