The Journal of The Institute of Image Information and Television Engineers

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As a result of its digital-multimedia initiative, Japan is preparing to introduce digital TV satellite broadcasting. Digital TV broadcasting is based on three scanning methods, namely 525i (480i) and 525p (480p) for SDTV and 1125i (1080i) for HDTV. The current 525i analog TV broadcasting and 1125i Hi-Vision broadcasting can also be performed by simulcast. In this paper, a new image detail creation system is described that enables displaying various kinds of TV-image sources in a single display. The system enables not only attaining a higher picture quality for the current 525i system in which the use of a small number of scanning lines degrades the picture quality but also harmonizing the new 525p and 1125i systems in which many kinds of scanning forms are used that are different from those used in the 525i system. By using an interpolation technique in the system, a 525i interlaced scanning image source can be converted with a double field rate and a double scanning line reducing the degradation due to the conventional interlaced scanning system. In the scanning-conversion procedure, image details and emphasis can be created and interpolated to enable a high-definition image. The display system can be evaluated using a response analysis of the two-dimensional spectrum of temporal frequencies and vertical spatial frequencies.

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A method is described for estimating the parameters of non-uniformly blurred images and restoring them. An original image is represented by a noncausal stochastic image model, which is driven by white noise. The blur process is modeled using a space-variant linear system. The parameters of the blurred image are estimated by maximizing a function that is the product of the local loglikelihood function of every pixel. A restoring filter on sliding window is applied to every pixel. Testing of the proposed method on simulated images and an actual non-uniformly blurred image showed that it can estimate the radius of out-of-focus blur and restore blurred images.

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A MAP (Maximum A posteriori Probability) receiver is described that is designed for Markovian sources in a wireless environment. A MAP receiver, a well-known efficient receiver, uses the stochastic characteristics of the source in the decision procedure. However, it is very difficult to implement a MAP algorithm at the front of the receiver because of its calculation costs. To reduce these costs we introduce a source predictor in the receiver. With the aid of the predictor, the MAP detector can be operated with a small calculation cost. Experimental PCM (Pulse Coded Modulation) image transmission demonstrated the feasibility of the proposed receiver. Simulation of the receiver's performance showed it had better MSE (Mean Squared Error) performance in spite of its implementation simplicity.

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