37 results about "Digital audio watermarking" patented technology

The invention discloses a digital audio watermarking method capable of resisting re-recording attack. The method comprises the following steps of: 1, watermark synchronization reference point extraction: dividing a carrier audio signal into audio frames with equal length, extracting the 12-dimension semitone characteristics of each audio frame, and thus obtaining watermark synchronization reference points; 2, watermark embedding: coding watermark information to obtain a binary watermark bit coding sequence, dividing a carrier audio into a plurality of watermark synchronization units, dividing each watermark synchronization unit into a plurality of audio sample sections, and embedding a watermark into a frequency spectrum of a low-frequency domain of each audio sample section through binary coding; and 3, watermark extraction: during the watermark extraction, dividing each watermark synchronization unit into the corresponding audio sample sections according to synchronization reference points extracted by parameters for the watermark embedding, respectively calculating a mean value of the frequency spectrum in a low-frequency spectrum interval of each audio sample section, and extracting the audio section interval watermark bit of each mean value. According to the method, the embedding position of the watermark can be accurately determined, and the re-recording attack can be resisted. The method is high in robustness.

The invention discloses a DWT-SVD-ICA-based digital audio watermarking algorithm. The algorithm is performed according to the following steps: the first step, preprocessing is performed on an original audio signal, and a watermark is embedded in a selected appropriate segment; the second step, when the watermark is embedded, three-level wavelet conversion is performed on the original audio signal, singular value decomposition is performed on an approximate component of the wavelet conversion, and then watermark embedment is completed by utilizing a random mixing method; and the third step, when the watermark is extracted, wavelet conversion and singular value decomposition are performed on the audio signal embedded with the watermark, and then watermark blind detection is achieved by utilizing a negentropy maximization fixed point algorithm. Compared with a traditional ICA-based audio watermarking algorithm, the DWT-SVD-ICA-based digital audio watermarking algorithm is advantageous in that watermark robustness is improved to some extent, that is to say, the watermark robustness is high; and imperceptibility of the watermark can be guaranteed, and blind extraction of the watermark can also be guaranteed.

The present invention relates to a method of detecting and recovering the voice signal tampering by using the digital audio watermarks. The method takes the compression version of an original signal as a watermark signal, so that the watermark signal does not contain other redundant information and also does not need other information relevant with the original signal at recovery, and accordingly, the watermarks have a self-recovery performance. According to the redundancy of a digital watermark signal, the watermark information is embedded in the least significant bits (LSBs) of the signal. The watermark signal can accurately position and recovers a signal broken area, and can have a satisfying recovery effect while keeping a higher signal to noise ratio.

The invention provides a robust digital audio watermarking algorithm in view of time-frequency analysis. The algorithm comprises steps of: first subjecting a selected audio segment to non-overlapping short-time Fourier transform to obtain a time-frequency distribution map of an audio signal, performing windowing and blocking in the low and medium frequency range of the time-frequency distribution map, and randomly selecting a characteristic energy block with low energy as a specific position for embedding a watermark; embedding generated binary watermark bits into the corresponding characteristic energy blocks by means of an extended code by using an improved spread spectrum watermark embedding method; after the watermark embedding, obtaining the characteristic energy blocks with embedded watermark by means of a watermark embedding position conveyed by a watermark embedder, and recovering a watermark sequence by using a watermarked characteristic energy block vector and the plus or minus characteristic of spread code inner product. The algorithm can guarantee the quality of a main signal by embedding the watermark into the low-frequency and low-energy position of the frequency domain, and can still recover the watermark after the watermarked signal is subjected to quantification, noise, amplitude zooming, AAC coding compression and low-pass filtering.

The invention relates to a method for authenticating digital audio copyright through digital watermarking, which solves the problem that the digital audio copyright in the prior art can not be protected. The invention discloses an existing government file-based system. The method comprises the steps: implanting digital audio watermarking in the intermediate link, conducting transcoding processing, effectively binding an audio source with the basic information of the file, conducting supervision and inspection on an sp service provider through a detection terminal so as to prompt standardization of digital music market, so that the technical effect of effectively protecting digital audio copyright can be achieved.