37 results about "Digital audio watermarking" patented technology

The present invention relates to a digital audio watermark inserting/detecting method and apparatus. The present invention provide the digital audio watermark inserting method having the step of encoding a digital audio signal by using a scale factor table, the method including the steps of: transforming the digital audio signal into a plurality of sub-band samples; extracting a scale factor being an amplitude factor of the transformed sub-band samples; transforming the extracted scale factor into a scale factor index by using the scale factor table; and inserting a watermark signal into the scale factor index in the transforming of the extracted scale factor. Accordingly, the present invention has an effect in that the additional noise or distortion is not caused while the watermark is effectively inserted.

The invention provides a method for embedding and extracting digital audio watermarks in a time domain on the basis of audio breakpoints, and an energy value of an original audio is directly changed on the basis of the original audio according to a numerical value of watermark information and the energy value of the original audio. Only little change is made on the basis of an original signal, and good robustness, cutting resistance and less information increase of watermarks are guaranteed on the premise that the hearing quality of the original audio is not influenced. In a watermark extraction link, the positions of the embedded watermarks can be automatically screened by an extraction algorithm, information which looks like watermarks in numerical logic is excluded, and the capability of storing original watermark information is provided. According to the method, the watermark information is encrypted. The used watermark extraction scheme is a blind watermark algorithm and can be used for processing audio signals, protecting audio products and the like, only fragmentation information of the original audio and reconstruction parameters of watermark signals are needed, and the participation of the original audio and original watermarks is not needed.

The invention provides a digital audio watermarking method based on an invariant characteristic of a histogram, which is characterized by comprising non-downsampling discrete wavelet transform, frequency domain histogram extraction, digital audio watermarking embedment, and digital audio watermarking detection. The digital audio watermarking method comprises the following steps: firstly carrying out the non-downsampling wavelet transform on original audio watermarking to obtain a low-frequency area with audio information and a high-frequency area with audio information; secondly, extracting the frequency domain histograms with the invariant characteristic from the audio low-frequency area; thirdly, processing the obtained frequency domain histograms, and grouping the frequency domain histograms, wherein each group contains four bins; for each group, the watermarking embedment for each watermarking position is finished by depending on reallocation of coefficients of the adjacent four bins in each group; and finally reaching the purpose of the digital watermarking embedment by revising the coefficient relationship of the adjacent four bins in each group in the frequency domain histograms. The digital audio watermarking method can preferably resist common attacks and synchronization attacks.

The invention discloses an automatic monitoring method and an automatic monitoring device of simulated broadcast signals. The automatic monitoring method comprises the steps: implanting source program identification a simulated broadcast audio frequency program stream output by a studio in a audio frequency watermark form, synchronously extracting the source program identification from the simulated broadcast audio frequency program stream in a monitoring point in the process of transmitting the simulated broadcast audio frequency program stream implanted with the source program identification, comparing the source program identification extracted from the simulated broadcast audio frequency program stream with accurate source program information, and reporting error when the source program identification extracted from the simulated broadcast audio frequency program stream is not confirm to the accurate source program information. According to the automatic monitoring method and the automatic monitoring device of the simulated broadcast signals, the simulated broadcast audio frequency program stream is implanted in the source program identification, attack and distortion by an audio processor are resisted, and no change is done to a broadcast framework of an existing simulated audio broadcast system, a plurality of monitoring points is arranged in the simulated audio broadcast system, under the condition that the listening effect of a wide audience is uninfluenced, whether the simulated broadcast audio frequency program streams broadcasted by different transmission positions are right or not is automatically monitored and error information is reported.

The invention discloses a robust digital audio watermark embedding and detection method based on polar harmonic transform. Advantages of great frequency domain localization features, multi-scale, redundancy and translation invariance, the features of non-stationary of greatly describing signals and maintaining the shape of the signals and the same length of audio frequency of each sub-band after decomposition with that of the original audio frequency of nonsubsampled wavelet transform are utilized; then great numerical stability of polar harmonic transform is also utilized, and watermarks are embedded in stable torque values to resist the normal signal attack; and then the synchronization code technology is combined. The experimental results indicate that normal signal processing can be resisted and the desynchronization attack can also be effectively resisted so that the method has great imperceptibility and robustness. Besides, the method also has advantages of being simple in design and easy to realize.

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.