To improve the watermark benchmarks database,a new BRA(Block Replacement Attack)method is introduced in this paper.Unlike the typical BRA which exploits the self-similarity among blocks in image,the scheme utilizes th...To improve the watermark benchmarks database,a new BRA(Block Replacement Attack)method is introduced in this paper.Unlike the typical BRA which exploits the self-similarity among blocks in image,the scheme utilizes the self-similarity in various scale and orientation bands in the wavelet domain of the image.They search the replacement blocks from the blocks of the smaller sub-image at the next lower resolution.The most important advantage of this scheme is that the pyramid sub-band decomposition acts as an automatic block classifier,with the result of simplifying the block search and block matching procedures and thus making the block replacement more effective.Furthermore,an improved algorithm based on Fuzzy set theory is introduced in which the number of blocks chosen for combination are modified adaptively to obtain the candidate replacement blocks.It simplifies the procedure for searching the candidate replacement blocks.These advantages are confirmed by the experimental results,which show that the performance of the scheme is superior to typical BRA methods.展开更多
A novel algorithm of global motion estimation is proposed. First, through Gabor wavelet transform （GWT）, a kind of energy distribution of image is obtained and checkpoints are selected according to a probability dec...A novel algorithm of global motion estimation is proposed. First, through Gabor wavelet transform （GWT）, a kind of energy distribution of image is obtained and checkpoints are selected according to a probability decision approach proposed. Then, the initialized motion vectors are obtained via a hierarcbal block-matching based on these checkpoints. Finally, by employing a 3-parameter motion model, precise parameters of global motion are found. From the experiment, the algorithm is reliable and robust.展开更多
In this paper, a robust DWPT based adaptive bock algorithm with modified threshold for denoising the sounds of musical instruments shehnai, dafli and flute is proposed. The signal is first segmented into multiple bloc...In this paper, a robust DWPT based adaptive bock algorithm with modified threshold for denoising the sounds of musical instruments shehnai, dafli and flute is proposed. The signal is first segmented into multiple blocks depending upon the minimum mean square criteria in each block, and then thresholding methods are used for each block. All the blocks obtained after denoising the individual block are concatenated to get the final denoised signal. The discrete wavelet packet transform provides more coefficients than the conventional discrete wavelet transform (DWT), representing additional subtle detail of the signal but decision of optimal decomposition level is very important. When the sound signal corrupted with additive white Gaussian noise is passed through this algorithm, the obtained peak signal to noise ratio (PSNR) depends upon the level of decomposition along with shape of the wavelet. Hence, the optimal wavelet and level of decomposition may be different for each signal. The obtained denoised signal with this algorithm is close to the original signal.展开更多
基金the Science Research Plan of Education Office of Shaanxi Province,China under Grant No. 11JK1048Science Research and Development Program Project of Shaanxi Province,China under Grant No. 2011K17-04-01
文摘To improve the watermark benchmarks database,a new BRA(Block Replacement Attack)method is introduced in this paper.Unlike the typical BRA which exploits the self-similarity among blocks in image,the scheme utilizes the self-similarity in various scale and orientation bands in the wavelet domain of the image.They search the replacement blocks from the blocks of the smaller sub-image at the next lower resolution.The most important advantage of this scheme is that the pyramid sub-band decomposition acts as an automatic block classifier,with the result of simplifying the block search and block matching procedures and thus making the block replacement more effective.Furthermore,an improved algorithm based on Fuzzy set theory is introduced in which the number of blocks chosen for combination are modified adaptively to obtain the candidate replacement blocks.It simplifies the procedure for searching the candidate replacement blocks.These advantages are confirmed by the experimental results,which show that the performance of the scheme is superior to typical BRA methods.
文摘A novel algorithm of global motion estimation is proposed. First, through Gabor wavelet transform （GWT）, a kind of energy distribution of image is obtained and checkpoints are selected according to a probability decision approach proposed. Then, the initialized motion vectors are obtained via a hierarcbal block-matching based on these checkpoints. Finally, by employing a 3-parameter motion model, precise parameters of global motion are found. From the experiment, the algorithm is reliable and robust.
文摘In this paper, a robust DWPT based adaptive bock algorithm with modified threshold for denoising the sounds of musical instruments shehnai, dafli and flute is proposed. The signal is first segmented into multiple blocks depending upon the minimum mean square criteria in each block, and then thresholding methods are used for each block. All the blocks obtained after denoising the individual block are concatenated to get the final denoised signal. The discrete wavelet packet transform provides more coefficients than the conventional discrete wavelet transform (DWT), representing additional subtle detail of the signal but decision of optimal decomposition level is very important. When the sound signal corrupted with additive white Gaussian noise is passed through this algorithm, the obtained peak signal to noise ratio (PSNR) depends upon the level of decomposition along with shape of the wavelet. Hence, the optimal wavelet and level of decomposition may be different for each signal. The obtained denoised signal with this algorithm is close to the original signal.
