Image retargeting is a technique for displaying an image on various devices adaptively. However, the conventional retargeting methods restrict target display's shape as rectangular. For expanding their application field, generalization of the shape of target display is useful. Yet, generalization of the existing methods is non-trivial due to the fact that the basic idea of their algorithm deeply rooted in this shape restriction. On the other hand, one of the retargeting approaches, so called warping based method that have high affinity with optimization problem, is proposed. In this paper, we propose a warping based generalized image retargeting. For generalizing the warping method, the main problem is to solve a repositioning problem of regions of interest (ROIs) in input image. By restricting their movable regions, we convexificate this problem and it allows us to use a conventional convex optimization algorithm. The obtained result shows that our method outperforms the conventional method.

The hybrid coding method combining the predictive coding with the orthogonal transformation and the quantization is mainly used recently. This paper proposes a new hybrid parallel Intra Coding based on interpolative prediction which uses correlations between neighboring pixels, including non-causal pixels. In order to get high prediction performance, the optimal quantizing scheme, which is used to cancel the error that expands when decoding, is used. Furthermore, a new type of block shape, which enables parallel coding, is proposed to simplify the processing of interpolative prediction. The result of comparison between proposed method and intra coding method in H.264 shows that the PSNR of proposed technique achieves 1 dB to 4 dB improvement in Luminance, especially for image with more details.

Many existing multi-view video coding techniques remove inter-viewpoint redundancy by applying disparity compensation in conventional video coding frameworks, e.g., H264/MPEG4. However, conventional methodology works ineffectively as they ignore the special features of the inter-view-point disparity. This paper proposes a framework using virtual plane (VP) for multi-view image compression, such that we can largely reduce the disparity compensation cost. Based on this VP predictor, we design a poxel (probabilistic voxelized volume) framework, which integrates the information of the cameras in different view-points in the polar axis to obtain a more effective compression performance. In addition, considering the replay convenience of the multi-view video at the receiving side, we reform overhead information in polar axis at the sending side in advance.

This paper presents a novel view interpolation method for reconstructing an intermediate all-in-focus image from defocused stereo images of a scene consisting of two depths. In the presented method, the novel view can be reconstructed as a sum of the filtered stereo images. The reconstruction filters are derived as stable and linear space-invariant ones; thus the presented method does not require estimation of feature correspondence. Experimental results on real images showed that view interpolation was possible with sufficient quality.

This paper deals with a view interpolation problem using multiple images captured with a circular camera array. An inverse filtering method for reconstructing a virtual image at the center of the camera array is proposed. First, we generate a candidate image by adding all correspondence pixel values based on multiple layers assumed in a scene. Second, we model a linear relationship between the desired virtual image and the candidate image, and then derive the inverse filter to reconstruct the virtual image. Since we can derive the inverse filter independent of the scene structure, the proposed method requires no depth estimation. Simulation results using synthetic images show that increasing the number of cameras and layers improves the quality of the virtual image.

This paper deals with a view interpolation problem using multiple images captured with a circular camera array. A novel deconvolution method for reconstructing a virtual image at the center of the camera array is presented and discussed in a framework of image restoration in the frequency domain. The reconstruction filter does not depend on the scene structure; therefore the presented method requires no depth estimation. The simulation result using synthetic images shows that increasing the number of the cameras improves the quality of the virtual image.

This paper proposes a H.264 rate control method considering picture characteristics and buffer constraints. Selecting the optimum buffer size corresponding to each application's requirement gives better compression quality and functionality. However, conventional methods allocate the number of bits equally to each GOP and do not explicitly consider the buffer size, where picture quality might not be optimal and the buffer size is not optimally determined for applications. This paper provides a bit allocation method that reflects the picture characteristic of each frame while keeping the buffer transition compliant within a given size. In the proposed method, the number of bits to be generated is estimated from the complexity of each frame, and it is adjusted by a scaling coefficient newly introduced in this paper. Thus, the allocated number of bits reflects picture characteristics and fully complies with buffer constraints. Experimental results show that the proposed method improves picture quality and suppresses quality fluctuation.

The authors describe a data syntax conversion method from CEPT (European standard) to Captain PLPS (Japanese standard) to permit interconnections between videotex services. They discuss the conversion results when an overseas videotex center, in particular, the Prestel (alpha-mosaic version in CEPT standard) center in the United Kingdom, is accessed from a Captain terminal using the described method. By the conversion method presented, the Captain terminal can access CEPT videotex centers as a CEPT terminal. There are two essential features. The first is that text and graphics data are converted into photographic information on Captain terminals to absorb differences of character size and graphic display. The second is that a color replacement method based on the major colors in a coloring unit is used to solve the problem of differences of coloring units between the two videotex services.>

A new hybrid coding method for transmitting videoconferencing images at a bit rate 384 kbits/s is proposed. Considering the characteristics of motion-compensated interframe prediction errors for typical videoconferencing scenes, a filter is introduced to separate pulsive components on which conventional discrete cosine transform (DCT) coding method does not work well. These separated pulsive components are coded by using scalar quantization (SQ). The remainder are DCT coded. For DCT coefficients, an adaptive coding method based on the classification of DCT coefficients is applied in order to improve the coding performance. Since the proposed method employs both DCT coding and SQ of prediction errors, it is named "DCT/SQ coding method." Experimental results show that the DCT/SQ coding method is effective to reduce so-called mosquito effects, and thus it can improve the quality of decoded images.

This paper describes a 15/30 Mbit/s TV codec with a new approach to high-efficiency coding for TV signals, i.e., median adaptive prediction. The 15/30 Mbit/s codec, commonly applicable to NTSC, PAL, and SECAM (525/60 and 625/50) systems, uses adaptive prediction incorporating a motion-compensated interframe, an interfield, and an intrafield predictor. Its performance for digital transmission is presented. This universal codec is designed, based on CCIR recommendations concerning digital TV coding parameters for studios (Rec. 601) and general principles on long-distance digital TV transmission (Rec. 604). A field trial of 15 Mbit/s digital TV transmission using this codec between earth stations with a 30 m diameter antenna and a 5 m diameter antenna is reported.

Since differential-pulse-code modulation (DPCM) and orthogonal transform coding (OTC) are the most fundamental methods of high-efficiency coding (bit-reduction method), it is important to clarify the basic coding characteristics of these methods and the difference between them in order to utilize the bit-reduction method effectively. This paper theoretically as well as experimentally compares the coding efficiency of a DPCM having a two-dimensional predictor with that of a two-dimensional Hadamard transform coding method (HTC) in the intrafield coding of the NTSC composite signal. The comparison evidenced that the distinctive difference in coding characteristics between DPCM and HTC depends greatly on the power level of carrier chrominance signals. That is, it is confirmed theoretically and experimentally that the coding efficiency of the HTC is far lower than that of the DPCM in the case of a signal having a high power level carrier chrominance signal such as a color-bar signal.

This paper proposes a new approach to the composite coding of the NTSC color TV signal, i.e., an interfield-intrafield adaptive prediction. First, concerning prediction efficiency for various moving pictures, an advantage of this coding scheme over interframe coding is clarified theoretically and experimentally. This adaptive prediction gives very good and stable performance for still to violently moving pictures. A 30 Mbit/s. codec, based on this idea, and its performance are presented. Field transmission testing through an INTELSAT satellite using this codec is also described. The picture quality is satisfactory for practically all the pictures expected in broadcast TV programs, and it is subjectively estimated to be a little better than that of the half-transponder FM transmission now employed in the INTELSAT system.