In conventional fractal image coding using by IFS (Iterated Function Systems), the IFS parameters are quantized and coded after their analog values are determined. But, quantization errors influence the reconstructed image. In this paper, we propose a quantization method to reduce the influence. In this method, the IFS paramters are selected from predetermined, quantized values.

View full abstract

This paper proposes, for image sequence coding, vector quantization of interframe prediction residues with thresholding. Interframe prediction residues are divided with thresholding into two groups, and we individually construct vector quantizers for them. Interframe prediction residues to be quantized are also divided with the thresholding, and they are quantized. In motion compensation, we use motion-table lookup. Various motion patterns are put into a motion-table. Each block of pixels is predicted through a motion that minimizes interframe prediction error. By combining the motion compensation using motion-table lookup and vector quantization of interframe prediction residues with thresholding, we realize efficient coding of image sequence.

View full abstract

This paper proposes a method of picture segmentation using a Genetic algorithm (GA). One of the picture segmentation methods is derived with a Markov random field (MRF). It analyzes the texture of a picture and segments it into some regions. However, if the picture has gradation regions, the method can not segment it accurately. Further, a total number of the regions need to be known before execution. The proposed method estimates the parameters and can segment a picture of which the brightness is gradually changed. In this paper, the performance of the proposed method is verified by some simulations.

View full abstract

In this paper, we propose a improvement of image quality for the fixed block size IFS with the bit rate kept low. In the case of a fixed block size, especially when the block size is large, we cannot represent details of images well while we can restrain the bit rate. In the proposed method, we improve image quality by searching similar regions closely for a block whose variance is large. Search is rough for a block whose variance is small. The adaptive process is based on the fact that MSE of each block of the reconstructed image and the variance of the corresponding block of an original image is closely correlated.

View full abstract

This paper proposes lossless image coding using a number-theoretic Hadamard transform. The number-theoretic Hadamard transform is derived from the Hadamard transform computed by modulo arithmetic. The transform effectively decreases the bit rate because all the coefficients are integer less than the modulus. Lossless image coding is performed with the transform. Statistics of the least significant bits and gray-scale remapping are used to decrease the bit rate. This paper also proposes quasilossless coding by revising image.

View full abstract

This paper proposes the use of a genetic algorithm for scaling-parameter identification. The conventional method quantize the parameters are identified by using the RMS metric and effect of quantization error increase when image is reconstructed. The genetic algorithm is constructed to cope with the problem. This paper shows the setting method of the genetic algorithm for parameter identification. Results of some experiments are included to show the effectiveness of the proposed method.

View full abstract

This paper presents a new coding method modifying the conventional layered representation, which describes moving images with overlapping layers stacked in their order of depth. For each segmented region, the layer consists of three maps which are usually generated by integrating all frames into one key frame. However, it is not enough to use only one intensity map for encoding a region in long sequence, because distortion of the map arises from motion estimation errors and transition of texture. To overcome this problem, we split image sequence into some short sequences of unequal length, and reconstruct sequence by mixturing multiple maps of key frames. Simulation results show that the proposed coding method achieves better visual quality compared to the conventional H. 263 method.

View full abstract

This paper describes a method of feature extraction for facial images to extract expressions using fractal-analysis. To extract the features, we proposed a method of a region segmentation by fractal dimention. Which in obtained by covering blanket method. This system can estimate the position of facial parts (such as eyes, nose, mouth) successfully. If the estimated results depend on the lighting conditions, it can estimete exactly using relationship between each facial parts. We try to analyze the shape of estimated facial features using template matching. If the shape change is large such as "laugh"and "yawn", this system can classify facial expressions into each categories. However if the change is subtle such as "sadness"and motion of eyes, it's cannot classfy.

View full abstract

We will propose an image coding method using a set of essential curved surfaces. We define the essential curved surfaces which are independent of the kind of images. First, we have examined about a size of block for the essential curved surfaces. The essential curved surfaces are determined based on the local features of images. Secondly the essential curved surfaces are compared with vectors made by LBG algorithm, and we have comfirmed the univarsal characteristics of code puttern based on the set of essential curved surfaces.

View full abstract

In this paper new multilevel codes for Rayleigh fading channel are presented. These codes are constructed by means of expnasion and division of the component codes to introduce an inter-dependency among them. The codes that can be obtained in this way are identified. We also show these bit error performance for multistage soft decision decoding (MSSD) and maximum likelihood decoding (MLD). Analytical result of the bit error perfomance agree well with simulation results at high SNR.

View full abstract

This paper develops a 2-D extension of the 1-D stability theory approach to equation error adaptive IIR filters. Then an algorithm based on the backpropagation formulation of 2-D equation error adaptive IIR filters with separable denominator function is proposed and its convegence analysis is considered. This algorithm is based on the concept of backpropagating the desired signal through a cascade of the denominator vertical and horizontal parts so that two linear error functions can be generated. Simulation results are presented to show that the proposed algorithm converges to the optimal solution when the desired signal is free from additive noise. However, if the desired signal is contaminated with additive noise, the proposed algorithm results in biased estimates. And thus, a bias removal method and its simulation results are presented.

View full abstract

We propose a new coding scheme of moving pictures based on region segmentation in this paper. Firstly, some problems to be solved in conventional coding scheme like MPEG-2 are examined from the viewpoint of improvement in coding performance. And, as one of the way to solve these problems, a picture coding scheme using motion-compensated prediction and orthogonal transform with arbitrarily shaped region based on segmentation is described. Finally, orthogonal transform using spline function with arbitrarily shaped region, which is one of the most important component to realize this proposed scheme, is studied.

View full abstract