Seisuke Kyochi

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In this paper, a novel design method of critically sampled contourlet transform (CSCT) is proposed. Although, several types of CSCT have been proposed, they have some problems on efficiency and flexibility of their frequency plane partition patterns. In contrast to the way in conventional design methods based on a "top-down" approach, the proposed one is(More)
In this paper, we propose a two dimensional (2D) non-separable adaptive directional lifting (ADL) structure of discrete wavelet transform (DWT) and its image coding application. Conventionally, we have proposed a polyphase representation of a 2D non-separable lifting structure of DWT. We generalize the polyphase representation in this paper and one(More)
The multiplierless fast Fourier transform (FFT) with dyadic-valued (rational) coefficients is important for many signal processing tools. The proposed lifting based FFT (L-FFT) based on fast Hartley transform (FHT) has a simpler structure than existing ones because fewer lifting steps need to be approximated. In addition, it has a structure of real-valued(More)
This paper proposes a directional and shift-invariant transform based on M-channel rational-valued cosine-sine modulated filter banks (R-CSMFBs) for the practical implementation on hardware devices. M-channel CSMFBs can be easily designed by the modulation of a prototype filter and achieve a good stopband attenuation. In addition, in our previous work, the(More)
Complex-valued conjugate-symmetric Hadamard transforms (C-CSHT) are variants of complex Hadamard transforms and found applications in signal processing. In addition, their real-valued transform counterparts (R-CSHTs) perform comparably with Hadamard transforms (HTs) despite their lower computational complexity. Closed-form factorizations of C-CSHTs and(More)
Complex-valued conjugate symmetric Hadamard transform (C-CSHT) is a variant of complex Hadamard transform and effective for some signal processing and communication applications. Its closed-form factorization of the general N-channel (N = 2<sup>m</sup>) case was recently proposed, however, there still exist a room to find an effective factorization(More)
In this paper, we propose a lattice structure of two-dimensional (2-D) linear-phase paraunitary filter banks (LPPUFBs) called as 2-D GenLOT. Muramatsu et al. have proposed a lattice structure of 2-D LPPUFBs conventionally. Our 2-D GenLOTs save design parameters and computational costs compared to the conventional 2-D LPPUFBs. We impose the regularity(More)
In this paper, we introduce a novel framework for lossless/near-lossless (LS/NLS) color image coding assisted by an inverse demosaicing. Conventional frameworks are typically based on prediction (and quantization for NLS coding) followed by entropy coding, such as the JPEG-LS for bit rate saving. The approach of this work is totally different from the(More)