A new technique for the high-resolution image synthesis called multifocus synthesis is presented. As an important extension, the 3-D real-world image capture is discussed. In the approach, the object image is taken at a number of focal distances by a single camera placed at a fixed position. Each of these images are then converted into the multiresolution using the optimized QMF. The resultant volume of coefficients are then analyzed and 3-D distance information is computed.

A coefficient-by-coefficient adaptive discrete cosine transform (DCT) is investigated. The interframe DCT has been known to possess an adverse effect in that it generates mosquito and blocking noise. By analyzing DCT for the intraframe and the interframe video signals, a new adaptive intra/interframe DCT is developed. Cases without and with the movement-compensation are discussed separately. Through simulations, it is shown that a substantial improvement gain (1.0-5.0 dB/sub p-p/ or 0.2-2.0 dB/sub p-p/, respectively) can be obtained by the new adaptive method. The improvement is brought about by the reduction of the blocking noise conventionally generated by the coarse quantization of the higher order interframe DCT coefficients. By calculating the improvement bound, a further possibility is discussed.>

Some of the implications of providing referential and general integrity are outlined. Different query execution strategies required to support such integrity are described. SIM (semantic information manager) is an object-based database management system that implements some of these strategies. The strategy implementation is described along with some optimizations that have been introduced into the system. Some unresolved issues are described with respect to integrity enforcement in object-oriented databases that support high-level languages.>

An iterative method for accurate movement estimation of television signals is analyzed. The method considered is based on an iterative process applied to the conventional gradient method. It is known that the gradient method has some problems both in its stability and in its accuracy for movements larger than 2 or 3 pel/frame. It is shown that when an iterative process is used, the estimated movement converges to the actual movement rapidly and is exponentially stable. It is also shown that the asymptotic accuracy of the iterative estimate is determined by the smoothness of the gradient and by the amount of the frame-to-frame noise. Some experimental results are given and compared to the theoretical result.>

A new method has been explored for improved standard conversion of television signals. The conventional conversion method for the frame-frequency produces a blurring-jerkiness problem and this can be effectively solved by movement-compensated interpolation. An accurate movement estimation and a means to evaluate its accuracy are the two key techniques for achieving this goal and hence are discussed in detail. It is shown that a small frame-to-frame difference does not necessarily imply an accurate estimation. A new accuracy measure is proposed and by using this, the new and the conventional methods are compared. Finally a new movement-compensated interpolation method is described and simulated results are reported.

Seeing-while-talking has been a dream of mankind for over a 100 years since the invention of telephone. In the past, various trials were performed in spite of the difficulty in installing the network for the actual service. However, with the progress of ISDN and the advancement of digital signal processing technology, the environment has been changing rapidly. In this paper, an integrated visual communication system is described for the enhanced communication service at 64 kbits/s, the fundamental bit rate of ISDN. The roles of state-of-theart compression of the audio and video signals are discussed and an integrated transmission method based on the priority of the information content is proposed.

A demand for color picture transmission is growing rapidly for various integrated services. For transmission, color pictures must be encoded, but it is widely understood that this can be most conveniently done in the form of luminance and chrominance signals, since the properties of the human visual system can be exploited to achieve considerable redundancy reduction. For encoding these component signals, it is most efficient if they can be jointly encoded. In this paper, a new combined encoding scheme is introduced for the luminance and chrominance signals based on the technique of vector quantization, taking into account the properties of the human visual system. However, these encoded signals are converted into primaryRGBsignals for display, and the corresponding increase of the encoding noise has not been discussed in the literature. In this paper, an encoding process is considered as a part of the total system between a camera and a display. Two different adaptive quantization schemes are incorporated in the encoding, and it will be shown that a good picture quality can be obtained with 2.0-2.5 bits/pel.

The encoding of colored pictures in components has attracted a lot of attention. In this paper, for their efficient transmission in the 2-3 bit/pel range, the direct encoding of the red (R), green (G), and blue (B) primaries is investigated. Differential PCM with vector quantization is used and the encoding efficiencies are compared to the similar result obtained using the properly converted luminance (Y) and chrominance (I,Q) component signals. A new quantization scheme is proposed forRGBencoding to improve the picture quality. As a result, it is shown thatRGBencoding can attain a comparable or slightly higher encoding efficiency as compared toYIQencoding, and a higher resolution can be obtained for strong color edges defined by the primary colors, but the resulting picture quality is much noisier; thus, it is better suited for such applications in which the edges of primary colors play important roles, such as in graphics materials. An adaptive vector quantization is introduced in order to apply the proposedRGBencoding scheme to a wider range of pictures. The quantity called activity is introduced, considering the form of the predictor used. The optimum adaptive scheme is derived and its effectiveness is verified through simulations.