58 results about "Integer wavelet transform" patented technology

The invention discloses an audio lossless compression encoding and decoding method and belongs to the field of information source encoding and decoding. In the method, a signal is framed adaptively according to related conditions of the former frame and the later frame of the signal, wherein a frame signal after framing is a combination of signals with similar signal characteristics, so that an encoder can achieve higher compression efficiency and is good for later integer wavelet transform and linear predictive encoding. For lossless compression encoding, a signal can be completely reconstructed, and the complete reconstructed characteristic of the signal is guaranteed by adopting integer lifting wavelet transform. Compared with the prior art, after a related adaptive framing-based module and an integer lifting wavelet-based de-correlation module are introduced, redundant information in an original signal can be well de-correlated, and the generated compressed data contains less redundant information. Therefore, the audio lossless compression encoding and decoding method can greatly improve the compression ratio by low computation complexity.

The inventions provides a method for compressing image data comprising the steps of: performing a color transformation of the data; wavelet-transforming the color-transformed data via division and multiplication operations being substituted with six lookup tables in order to provide a series of wavelet coefficients in different levels of wavelet transformation subbands; quantizing in accordance with a special equation the wavelet coefficients which fall above a predetermined threshold value to provide a series of quantized wavelet coefficients; applying an entropy coding to the quantized wavelet coefficients with a particular Huffman table; and compressing the coded wavelet coefficients to provide compressed data.

A vector geographic space data watermarking-method based on integer wavelet transform includes fetching original vector geographic space data from mapping databank, enciphering watermark information with chaos sequence, carrying out integer wavelet transform on coordinate string of said geographic space data and embedding watermark information into low frequency coefficient of wavelet transform; picking up watermark information by comparing wavelet coefficient mutual relation of data string to be tested to original reference data string when watermark is required to be picked up.

Enhanced method for embedding watermarks based on integer-to-integer wavelet transform is provided. The method according to the present invention includes the steps of: (A) dividing an original image (X×Y) to a plurality of image blocks (M×N); (B) selecting image blocks for embedding an location information that indicates image blocks to be watermarked;(C) embedding the location information into the image blocks selected in the step (B); and (D) embedding watermarks into remaining image blocks which are not selected in the step (B).

The present invention discloses a compressing method of the data recorded by the electric power waveform. The compressing process includes the steps of: the collected data is performed by the integer small wave conversion based on the rising format and then all the data having been converted is coded in the Huffman method; the decompressing process includes the steps of: each pressing data that is read in bit is decoded in Huffman method, and then the data having been decoded is performed by the integer small wave contra-conversion. The present invention has the characteristics of a small amount of computing, a high compressing rate, a small distortion factor, a small occupied computer resources, etc. and the method can be realized in a flushbonding system. The compressibility and the distortion factor can be adjusted according to the demand and the flexibility of the using of the software is added. The present invention can also provide a threshold value to the detail information to realize the lossless compressing and the lossy compression. The electric power system waveform recording device in the present can realize a long-time and continuous recording waveform by combining the electric hardware technology under the situation of high sampling rate and big capability and the waveform can be transmitted far away through the communication interface reliably and quickly.

A system and method are disclosed which may include subjecting an original, pixel domain image to an Integer Wavelet Transform (IWT) to obtain a first matrix of IWT coefficients; multiplying selected ones of the IWT coefficients by two; and embedding a data bit in a LSB (Least Significant Bit) position of each selected coefficient, thereby providing a marked image.

The invention discloses a method for extracting a remote sensing image interesting area based on multi-scale feature fusion, and belongs to the technical field of remote sensing image processing. The method comprises the following steps: (1) adopting a saliency analysis method based on a multi-scale spectrum residual error to generate a multi-scale low frequency saliency image of the remote sensing image, (2) obtaining multi-scale high frequency saliency images in the horizontal direction, the perpendicular direction and the diagonal direction through integer wavelet transformation, (3) obtaining a luminance saliency image and a direction saliency image through cross-scale weighting and cross-scale fusion, (4) combining the luminance saliency image and the direction saliency image to generate a main saliency image, and (5) carrying out threshold segmentation to extract the interesting area through the OTSU. Compared with a traditional method, the method has the advantages of being low in computing complexity and effectively improving area extraction efficiency and area extraction accuracy. Due to the fact that spectrums and color information of the remote sensing image are not required to be obtained, the method can be directly used for interesting area extraction of a high-resolution full-color remote sensing image. The method has good application value in the fields of land planning, environment monitoring, forestry investigation and the like.

A method is provided which comprises providing a block of IWT (integer wavelet transform) coefficients for preferably one high frequency sub-band of an image; determining a mean value of said coefficients within said block; and establishing an encoded mean value to embed one of a logical-0 bit value and a logical-1 bit into said first block.

A nondestructive watermark method based on integer wavelets features that a computer software is used to embed data in the digital image which can be restored without destruction, and includes embedding the digital watermark and extracting it. For embedding digital watermark, the steps are first to regulate the grayscale histogram, wavelet conversion, embedding data, reverse conversion of wavelet, and the second regulation of grayscale histogram to form the addition of watermark picture. Extracting digital watermark includes such steps as the third regulation of grayscal histogram, conversionof wavelet, extracting data, reverse conversion of wavelet and the fourth regulation of grayscal histogram. It can ensure that the images before and after the watermark is embedded have the smalest visual difference.

The invention discloses an image compression method and device for real-time code rate pre-distribution. The method comprises the steps of transform, code rate pre-distribution and entropy coding, wherein multilevel integer wavelet transform is adopted in the transform to remove related redundancy among original image pixels, to-be-contributed code rate of each sub band in actual coding is guidedby combining the rate distortion theory and the importance principle of each sub band of the transformed image on image reconstruction quality influence, and the final entropy coding is guided by using the pre-distributed code rate to realize real-time stop of the coding rate. The tasks of the method are divided in the compression device, the compression device comprises a field programmable gatearray (FPGA) and a digital signal processor (DSP), high-speed multilevel integer wavelet transform is realized by using the FPGA, and the transformed data are transmitted to the DSP through a high-speed serial input output (SRIO) module interface and are compressed and coded. By using the current most typical embedded architecture and combining the corresponding mathematical principle, the storage space of mass data is effectively saved, and the limited transmission bandwidth problem is solved.

The invention discloses a lossless compression method of curve vector data based on integer wavelet transformation and bit plane coding. In the invention, the integer wavelet transformation is introduced in a vector data compression algorithm. The integer wavelet transformation can compress the majority of energy of the data in a low-frequency coefficient and only the minority of energy in a high-frequency coefficient. In the invention, the low-frequency coefficient is coded by using the Huffman coding scheme and the high-frequency coefficient is coded by using a plane coding scheme. The embedded coding of the vector data can be achieved by the bit plane coding. The designed bit plane coder can sequence the bit streams to be coded according to the different importance, and the coding is finished at any time according to the requirements of a target code rate or a degree of distortion. Similarly, a given code stream decoder can finish decoding at any time, and the reconstruction vector curve of the target code rate at a corresponding place where the code stream is cut off can be obtained. Experiments show that the compression scheme achieves the embedded coding of the vector data, can progressively transmit and display the compressed code streams of the vector data, and simultaneously obtains a relatively high lossless compression ratio.

A wavelet-based image compression system and method are presented. Compression is accomplished by performing a wavelet transformation of an input digital image. The resulting wavelet coefficients are compared to a threshold value. Coefficients falling below the threshold are discarded. The remaining coefficients are quantized. The quantized coefficients are then compressed using an entropy encoding technique, such as arithmetic, run length, or Huffman encoding, or a combination of Huffman and run length encoding. The wavelet transform can be an integer wavelet transform derived using a lifting scheme or correction method, while the quantization scheme can be sub-band oriented. Input color image pixels can be reduced using a color table. In addition, color pixels can be transformed between color spaces prior to wavelet transformation.

The invention relates to the field of image processing and digital watermarking. The invention discloses a robust reversible image watermarking algorithm based on invariant features. The robust reversible image watermarking algorithm comprises watermark embedding and watermark extracting, wherein watermark embedding and watermark extracting are achieved by improving cat face scrambling transformation, normalization processing, scale invariant feature transform (SIFT operator), a level set method, integer wavelet transformation, singular value decomposition, an odd-even quantization algorithm and the like to process an original image and a watermark. Compared with the prior art, the robust reversible image watermarking algorithm has the advantages that the original carrier image can be completely recovered after the watermark is extracted, and the algorithm reversibility is realized; the robust reversible image watermarking algorithm has good transparency, has high robustness to conventional attacks and general geometric attacks, is high in overall performance, and can maintain good image visual quality; and the embedding size of the watermark can be adaptively determined, and the capacity of resisting attacks such as scaling is resisted.

The invention discloses a reversible database watermark embedding and extracting method based on integral wavelet transformation. In a database carrier, numeric attribution values are selected randomly to form a data set, the data set is divided into data subsets of the same size, and accordingly data arrays are formed; according to an overflow prevention mechanism, type groups where the data arrays belong to are determined; furthermore, watermark hiding models are adopted for the data arrays of different types so that watermarks of different intensities are embedded into wavelet domains of the data arrays to form a watermark database; finally, the watermarks are extracted by judging parity of expressions, and a watermark carrier coefficient vector translates reversely in a space formed by orthogonal vectors to restore the database carrier. According to the method, watermark information can be evenly distributed in each part of data in a database to achieve the aims of weakening influences of the watermark information on the database and improving invisibility and robustness of watermarks, and the method is suitable for copyright and integrity protection of a specific database.

A system and method are disclosed which may include subjecting an original, pixel domain image to an Integer Wavelet Transform (IWT) to obtain a matrix of IWT coefficients; selecting a plurality of the IWT coefficients for incorporation of information therein; and setting signs for the plurality of selected IWT coefficients according to bit values of a plurality of respective data bits. The system and method can also include subjecting a marked pixel domain image to an Integer Wavelet Transform to obtain a matrix of wavelet coefficients; selecting a plurality of the coefficients from the matrix that contain embedded information; and for each selected coefficient, extracting the data bit embedded in the coefficient, a bit value of the extracted data bit determined based on a sign of the coefficient.

The invention provides a medical image wavelet-domain real-time encryption and decryption algorithm based on a multi-chaos system. The medical image wavelet-domain real-time encryption and decryptionalgorithm based on the multi-chaos system includes the following steps of decomposing a medical image, encrypting wavelet coefficients, obtaining the encrypted medical image, and decrypting the medical image. Compared with related technologies, the medical image wavelet-domain real-time encryption and decryption algorithm based on the multi-chaos system adopts LeGaII5/3 integer wavelet transform to conduct three-grade wavelet grading on the initial medical image, and thus the relevance among pixels of the medical image is fully reduced; the medical image wavelet-domain real-time encryption anddecryption algorithm based on the multi-chaos system has high time efficiency and high security at the condition that an initial chaos value and system parameters are unknown.

The invention discloses an underwater video compression method, which comprises intraframe compression and interframe compression of an image to be compressed. The image to be compressed is YUV spatial data. The method also comprises the step of wavelet transformation pretreatment of the image to be compressed before intraframe compression and interframe compression. The wavelet transformation pretreatment comprises the following steps: conducting at least first-order integer wavelet transformation of the Y-component of the image to be compressed, and rejecting at least one high-frequency component selected from LH, HL and HH. The method rejects at least part of the high-frequency components of the Y-component after wavelet transformation of the image to be compressed and remains the low-frequency component of the U and V components after wavelet transformation, so as to reduce data quantity to be encoded, thereby increasing compression ratio from another aspect under the premise of ensuring the image quality.

The integer wavelet transformation method based on digital signal processor is characterized by that when the wavelent is undergone the process of positive transformation, firstly, dividing the image data into several data sections, then respectively making line data of current data section undergo the process of line positive transformation, and making column data of current data section undergo the process of column positive transformation, and when the vavelet is undergone the process of inverse transformation, firstly, dividing the image data into several data sections, then respectively making column inverse transformation of column data of current data section and line inverse transformation of line data of current data section, crossly making line and column transformation until the whole image data are processed completely.

The invention discloses an improving method based on the Huffman lossless compression algorithm. By the method, the redundancy of original data is reduced, the data energy concentration ratio is improved, and the compression ratio is improved. The method comprises the following steps of (1) performing block-based DPCM (Differential Pulse Code Modulation) algorithm; (2) performing integer wavelet transformation; (3) classifying, sequencing and finishing data; (4) adopting Huffman compression coding; (5) adopting the Huffman decompression algorithm; (6) restoring each level of wavelet coefficient sub-band; (7) performing integer wavelet inverse transformation; and (8) performing decompression algorithm of DPCM.

The invention discloses a method for embedding reversible watermarks in duplex domains for digital copyright verification. The method comprises a data embedding process and a data extraction and image recovery process. By aiming at the defects of small embedding capacity and image visual quality reduction of a reversible watermark method provided in the prior art, the method is based on the limited contrast enhancement, and realizes a reversible watermark algorithm for performing duplex embedding in a space domain and a transform domain by combining integer wavelet transformation. Firstly, the watermark information is embedded in the space domain in a reversible way; the image visual quality is improved through controlling the contrast enhancement index; and then, the watermark embedding is performed by using a detail sub-band in the integer wavelet transform domain. The characteristics of the image contrast are hardly changed. More watermarks are embedded in the transform domain, so that the visual quality of the image subjected to the watermark embedding can be better improved; and meanwhile, more watermark information can be embedded. The watermark embedding capacity and the image quality are effectively improved.

The invention provides a reversible watermarking algorithm of a ciphertext image. The method relates to the field of image information security and encrypted signal processing. The method comprises the following steps: directly embedding watermark information in a high-frequency area sub-band of the image according to a key after performing integer wavelet transform on the ciphertext image, and removing data expansion by corresponding inverse transformation and multiplicative inverse methods to obtain a ciphertext picture containing watermark; and performing the same transformation at a receiving end, directly extracting the watermark according to the key, and performing lossless recovery of the original image after decryption. The method has the advantages of high embedding capacity, high security, reversible watermark extraction, and capability of realizing lossless or approximately lossless watermark embedding and extraction of the image.