Takuma Ishida

Invertible deinterlacing with sampling-density preservation: theory and design

A novel class of deinterlacing for intra-frame/field-based motion-picture coding, such as Motion JPEG2000, as well as an inter-frame-based coding without the support of interlaced scanning video, such as MPEG-1, is developed. This technique has two features: sampling-density preservation and invertibility. These features mean that the amount of deinterlaced pictures is not increased, and the original pictures can be perfectly reconstructed. This deinterlacing technique is a kind of sampling-lattice alteration and is regarded as a generalization of conventional field interleaving and field separation. With the help of multidimensional (M-D) multirate theory, it is shown that the design problem of such a system, that is, invertible deinterlacer with sampling-density preservation, can be replaced to finding a 2/spl times/2 multivariable polynomial matrix with a monomial determinant. This problem resembles the design of two-channel M-D maximally decimated perfect-reconstruction finite-impulse-response (FIR) filterbanks. The inverse system, which is referred to as a reinterlacer , is given as FIR when the dual deinterlacing system is FIR. A practical design procedure is provided by suggesting three constraints considered to be preferable: normalization, regularity, and vertical symmetry. The significance of the procedure is verified by showing some design examples of deinterlacing and reinterlacing filters. Simulation results show that the developed method causes fewer comb-shaped artifacts than conventional field interleaving.

A design method of invertible de-interlacer with sampling density preservation

A new class of de-interlacing is developed for intra-frame-based motion picture coding such as Motion-JPEG2000. The proposed technique has two features: the sampling density preservation and the invertibility. Thus, the amount of de-interlaced pictures is not increased and the original pictures can perfectly be reconstructed. This technique is regarded as a generalization of the conventional field interleaving. The significance is, verified by showing some design examples and simulation results, The proposed technique is also shown to cause less comb-shape artifacts than the conventional one. The intra-field-based case is also discussed.

Invertible deinterlacing with variable coefficients and its lifting implementation

Invertible deinterlacing with variable coefficients is proposed to suppress comb-tooth artifacts caused by field interleaving of interlaced scanning video. A vertical highpass filter is applied to detect moving artifacts around boundaries of moving objects. The coefficients of a deinterlacing filter are varied depending on the motion intensity so that the deinterlacing filter may be matched to the local characteristics of moving pictures. Note that the deinterlacing filter is motion-adaptive and is time/translation-varying, while the deinterlacing is still kept to be invertible. The deinterlacing filter performance and its contribution to intraframe-based video coding is evaluated. In addition, since the processing of motion detection and a part of deinterlacing filtering can be shared, their efficient implementation is derived in the form of lifting popular in wavelets.

DWT gain compensation of motion-JPEG2000 for invertible deinterlacer

In this work, discrete-wavelet-transform (DWT) gain compensation of Motion-JPEG2000 (MJP2) for invertible deinterlacer is proposed. As previous works, we have developed invertible deinterlacer that suppresses comb-tooth artifacts caused by field interleaving for interlaced scanning video, which affect the quality of scalable intraframe-based codec such as MJP2. Our technique has two features that the sampling density is preserved and the image quality can be recovered by the inverse process on demand. When no codec is applied in between the deinterlacer and inverse process, the original video is perfectly reconstructed. Otherwise, it is approximately recovered. The purpose of this work is to improve the quality of recovered images when MJP2 codec is inserted. It is shown that our invertible deinterlacer can be embedded into the DWT. As a result, frequency weighting for rate-distortion control can be moderately compensated. Simulation results show that the quality recovery is improved more than 1.5 dB in PSNR by applying the proposed compensation compared with the original weighting at 2.0 bpp of decoding rate for 8-bit grayscale pictures.

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.

Parameter Embedding in Motion-JPEG2000 through ROI for Variable-Coefficient Invertible Deinterlacing

In this paper, a coefficient-parameter embedding method into Motion-JPEG2000 (MJP2) is proposed for invertible deinterlacing with variable coefficients. Invertible deinterlacing, which the authors have developed before, can be used as a preprocess of frame-based motion picture codec, such as MJP2, for interlaced videos. When the conventional field-interleaving is used instead, comb-tooth artifacts appear around edges of moving objects. On the other hand, the invertible deinterlacing technique allows us to suppress the comb-tooth artifacts and also guaranties recovery of original pictures. As previous works, the authors have developed a variable coefficient scheme with a motion detector, which realizes adaptability to local characteristics of given pictures. However, when this deinterlacing technique is applied to a video codec, coefficient parameters have to be sent to receivers for original picture recovery. This paper proposes a parameter-embedding technique in MJP2 and constructs a standard stream which consists both of picture data and the parameters. The parameters are embedded into the LH1 component of wavelet transform domain through the ROI (region of interest) function of JPEG2000 without significant loss in the performance of comb-tooth suppression. Some experimental results show the feasibility of our proposed scheme.