Reversible non-expansive symmetric convolution for M-channel lifting based linear-phase filter banks

2012 ◽  
Author(s):  
Taizo Suzuki ◽  
Masaaki Ikehara
Keyword(s):  
Filter Banks ◽  
Linear Phase ◽  
Phase Filter ◽  
Symmetric Convolution

Phase Watermarking of Images with Complex-Valued Linear-Phase Subband Filter Banks

2013 ◽  
Vol 339 ◽  
pp. 275-280
Author(s):  
Li Chen ◽  
Rong Hua Peng
Keyword(s):  
Frequency Band ◽  
Filter Banks ◽  
Low Frequency ◽  
Linear Phase ◽  
Time Frequency ◽  
Frequency Spread ◽  
Phase Filter ◽  
Dct Domain ◽  
Dct Coefficients ◽  
Complex Valued

A new algorithm is proposed for digital watermarking by applying complex-valued linear-phase filter banks to low frequency-band coefficients of images in the DCT domain. The watermark is conveyed in the phase spectrum of the subband coefficients. The robustness of the algorithm is examined in JPEG encoding with different qualities and compared with the DFT-based approach. Because only low frequency-band DCT coefficients are applied to complex-valued filter banks, the computational load introduced by the complex-valued filter banks is kept low. The watermark decoding is only accessible to users with the key information, i.e., impulse responses of the complex-valued linear-phase filter banks that designed with time-frequency spread property.

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