Yoshihiro Kikuchi

A study on fast rate-distortion optimized coding mode decision for H.264

The H.264 video coding standard can achieve considerably higher coding efficiency than any other existing standards by deciding the best mode among many prediction modes and various sixes of prediction blocks. Although the coding efficiency is improved by using Lagrange optimization for the mode decision, computational complexity increases significantly at the encoder. In this paper, we propose the fast rate-distortion optimization method for the hierarchical and adaptive coding mode decision in order to reduce the number of candidates for the best coding mode.

Adaptive bi-predictive video coding using temporal extrapolation

In this paper, we propose a new multi-frame bi-predictive motion compensation method using a temporal linear extrapolation technique. Significant coding gain is obtained by the proposed method, especially for fading or dissolving scenes, which are among the most difficult scenes to compress by conventional coding standards. Moreover, stable improved coding efficiency is obtained, using block by block adaptation combined with multiframe averaging prediction. The number of reference frames for the proposed temporal prediction method is limited to two successive frames which are already coded. And therefore only addition, subtraction and shift operation are needed to generate the prediction signal of both extrapolation and averaging. As for encoding, automatic adaptation is performed without scene characteristics detection, such as fade-in, fade-out, and dissolve. Therefore, additional computational power for both encoder and decoder to use the proposed method is very small.

Implementation and optimization of software depth estimation for arm

3D imaging capable devices have been available on the market for a few years now and the availability of 3D contents is also picking up. However, 3D contents available for viewing is not growing fast enough to meet the demand. To compensate for such a problem, most 3D imaging devices are equipped with 2D to 3D conversion function. Also, common 3D contents available are mostly produced with 2 view points which poses a problem for autostereoscopic devices that is capable of displaying multiple view points. In the absence of multiview 3D contents, to produce natural viewing experience on such device, depth estimation is an essential technology in order to create more parallax images from source images. In this paper, we present the implementation of Toshibas software depth estimation process on ARM processor which allows realtime processing on embedded devices such as TVs, mobile phones and tablet computers adopting stereoscopic or autostereoscopic 3D technology.

Implementation and Optimization of software 2Dto3D conversion for ARM

3D imaging capable devices have been available on the market for a few years now but the number of 3D contents available for viewing is not growing fast enough to meet the demand. To compensate for such a problem, most 3D imaging devices are equipped with a 2Dto3D conversion function. In 2Dto3D conversion, depth estimation is essential in order to create pseudo 3D images. Often, such conversion involves complex computations and is difficult to process in a real-time manner. In this paper, we present the implementation of Toshibas software 2Dto3D conversion solution, in particular, the depth estimation process on ARM processor. This could potentially allow real-time processing on embedded devices such as TVs, mobile phones and tablet computers.

Mobile Image Media and Picture Coding. Error Resilient Motion Picture Coding for Mobile Video Communication.

A motion picture coding scheme with high error resiliency that is applicable to wireless communication is proposed. Two methods are introduced to minimize the degradation of decoded images : re-synchronization method recovers synchronization from bit-slip of a VLC and two-way decoding using reversible VLC. To recover erroneous decoded images, an adaptive refreshing method is applied in which the encoder selects non-stationary areas for refresh by using the coding mode of the past frames. Simulation results show that the proposed scheme has high error resiliency and is applicable to high error prone environments with BER larger than 0.1%.