Minoru Hiki

Boundary Operation of 2-D Nonseparable Linear-Phase Paraunitary Filter Banks

This paper proposes a boundary operation technique of 2-D nonseparable linear-phase paraunitary filter banks (NS-LPPUFBs) for size limitation. The proposed technique is based on a lattice structure consisting of the 2-D separable block discrete cosine transform and nonseparable support-extension processes. The bases are allowed to be anisotropic with the fixed critically subsampling, overlapping, orthogonal, symmetric, real-valued, and compact-support properties. First, the blockwise implementation is developed so that the basis images can be locally controlled. The local control of basis images is shown to maintain orthogonality. This property leads a basis termination (BT) technique as a boundary operation. The technique overcomes the drawback of NS-LPPUFBs that the popular symmetric extension method is invalid. Through some experimental results of diagonal texture coding, the significance of the BT is verified.

Block-wise implementation of directional GenLOT

This paper introduces block-wise implementation of 2-D non-separable linear-phase paraunitary filter banks (LPPUFB) and shows a directional design approach. As a previous work, the authors have proposed a lattice structure of non-separable LPPUFBs which guarantees both of the linear-phase and orthogonal property. This paper shows that the structure serves variability of basis images without any violation to the orthogonality. Consequently, a boundary operation for size-limitation is yielded and compatibility with the 2-D separable block-DCT becomes possible since the lattice structure is based on the block-DCT. The main advantage of non-separable systems is its directional capability, and it is allowed to produce a directional non-separable GenLOT. Although the adaptive control of basis images is under investigation, experimental results of texture coding show prospective significance of the directional GenLOT.

Suppression of PSNR Fluctuation in Motion-Compensated Temporal 1/3-Transform Through Non-Separable Sub-Sampling

In this work, a novel motion compensated spatio-temporal filter (MCSTF) is proposed for scalable video coding. MCSTF is an alternative technique of existing motion-compensated temporal filtering (MCTF), a fundamental component for scalable video coding in next generation. MCSTF is a non-separable sub-sampling version of MCTF and provides interlaced pictures as intermediate video sequence by using a spatio-temporal split process. Furthermore, the 1/3-transform structure, which excludes the lifting-update-step, significantly suppresses the PSNR fluctuation which occurs in the existing MCTF technique. Our proposed system has an advantage of suppressing PSNR fluctuation with almost the same average PSNR as that of existing MCTF. In this paper, two types of sub-sampling lattices are investigated: the vertical-temporal (VT) quincunx and face-centered orthorhombic (FCO) lattices. Some experimental results with entropy coded scalar quantization show the significance of our proposed technique.

Equivalent Parallel Structure of Deinterlacer Banks and Its Application to Optimal Bit-Rate Allocation

In this paper, theoretical properties of deinterlacer banks are analyzed. Deinterlacer banks are novel filter banks in the sense that a progressive video sequence is separated into two progressive video sequences of a half frame rate and, furthermore, interlaced sequences are produced as intermediate data. Unlike the conventional filter banks, our deinterlacer banks are constructed in a way unique to multidimensional systems by using invertible deinterlacers, which the authors have proposed before. The system is a kind of shift-varying filter banks and it was impossible to derive the optimal bit-allocation control without any equivalent parallel filter banks. This paper derives an equivalent polyphase matrix representation of the whole system and its equivalent parallel structure, and then shows the optimal rate allocation for the deinterlacer banks. Some experimental results justify the effectiveness of the optimal rate allocation through our theoretical analysis.

Performance evaluation of spatio-temporal multi-resolution analysis with deinterlacer banks

In this work, hierarchical motion compensated three-dimensional (3-D) filter banks for spatio-temporal multi-resoution analysis are presented as new tools for scalable video format control. For recent developments in scalable video coding, most of them are based on 3-D wavelet transform with motion compensation. To achieve the function of frame-rate and spatial resolution scalabilities, motion compensated temporal filtering (MCTF) through lifting wavelet transform currently attracts many researchers as an effective temporal decomposition tool. As previous works, we proposed single stage deinterlacer banks as novel 3-D filter banks. Unlike other filter banks, our proposed system is constructed in a way unique to multi-dimensional systems by using invertible deinterlacers, which we have proposed before. The single stage deinterlacer banks decompose a progressive video into two subband sequences of a half frame-rate in the progressive scanning manner. Even though the system handles interlaced videos as intermediate data, introducing a multistage decomposition is simply achieved because the output sequences have also the progressive format as like the input. Our proposed hierarchical deinterlacer banks are accompanied by 2-D discrete wavelet transforms (DWT) as spatial transforms. The multistage technique provides interlaced sequences as well as several reduced-rate progressive sequences while maintaining the reconstruction of the original full-resolution full-rate video sequence. We show that fine granular control of spatio-temporal resolution can be acchieved through the hierarchical process. Some experimental results show novel functions and the significance of the proposed filter banks.