This paper proposes the dense correspondence field estimation with the stochastic diffusion based on maximum a posteriori (MAP) estimation. MAP-based correspondence field estimation including line field is derived with reflecting the joint probabilistic distribution function (PDF) of the neighborhoods in the Markov random field (MRF) models, and is applied to the stereoscopic images. The exploits of the joint PDF of the neighborhoods is the main difference from the previous MAP-based algorithms. The segmentation field is introduced in the low activity region, where the intensities are uniform, in order to improve the performance of the correspondence estimation. According to the experiments, the proposed algorithm had good estimation performance with fast convergence. Especially, the line field improved the estimation at the object boundaries, and the segmentation field did effectively in the low activity region.

This paper proposes a new subband coding approach to compression of document images, which is based on nonlinear binary subband decomposition followed by the concatenated arithmetic coding. We choose to use the sampling-exclusive OR (XOR) subband decomposition to exploit its beneficial characteristics to conserve the alphabet size of symbols and provide a small region of support while providing the perfect reconstruction property. We propose a concatenated arithmetic coding scheme to alleviate the degradation of predictability caused by subband decomposition, where three high-pass subband coefficients at the same location are concatenated and then encoded by an octave arithmetic coder. The proposed concatenated arithmetic coding is performed based on a conditioning context properly selected by exploiting the nature of the sampling-XOR subband filter bank as well as taking the advantage of noncausal prediction capability of subband coding. We also introduce a unicolor map to efficiently represent large uniform regions frequently appearing in document images. Simulation results show that each of the functional blocks proposed in the paper performs very well, and consequently, the proposed subband coder provides good compression of document images.

We derive the general formula of Bayesian model for stereo matching algorithm and implement it with simplified probabilistic models. The probabilistic models use the independence property and similarity between the neighborhood disparities in the configuration. The formula is the generalization of the Bayesian model of stereo matching, and can be implemented in the different forms corresponding to the probabilistic models in the disparity neighborhood system or configuration. We propose a new probabilistic model in order to simplify the joint probability distribution of the disparities in the configuration. According to the experimental results, we can conclude that the derived formula generalizes the Bayesian model for the stereo matching algorithm, and the simplified probabilistic models are reasonable and approximate the pure joint probability distribution very well. Compared with the conventional method of the Bayesian model and the sum of squared difference (SSD) algorithm, furthermore, our proposed algorithm outperforms the others.

This article proposes deadzone-constrained pruned tree-structured vector quantization (DCPTSVQ) which is suitable for transform coding of image or speech. DCPTSVQ applied to transformed signals considerably improves the rate-distortion performance with remarkably reduced codebook storage when compared with conventional PTSVQ.

On a Rayleigh-fading channel, multilevel codes achieve larger Hamming distances than single-level codes at comparable decoder complexity and bandwidth efficiency by employing a multistage decoder. Typically, multilevel codes are designed using Ungerboeck's (1982) set partitioning. This results in a large path multiplicity that degrades the code performance significantly. In order to overcome the performance degradation, we propose a set partitioning method that greatly reduces the path multiplicity.

We present an error concealment method to recover damaged blocks for block-based image coding schemes. The recovery problem considered in our method is to estimate a larger block, which consists of a damaged block and the undamaged neighborhood, from the undamaged neighborhood. To find an accurate estimate, an overcomplete basis is introduced and an estimate is expressed as a linear combination of the basis vectors. The projections onto the overcomplete basis algorithm is proposed to find the projection coefficients to minimize the squared difference of an estimate and the undamaged neighborhood information. The reconstructed images by the proposed method provide a good subjective quality as well as an objective one.

A region constrained warping prediction (RCWP) is proposed for motion compensation based on segmentation information. In contrast to the conventional warping prediction, the RCWP scheme allows motion discontinuities (MD) in the motion field which usually exist along the boundaries of moving objects. For the mesh points located on the boundaries, multiple motion vectors are assigned, and only one motion vector is assigned for the others as in conventional warping prediction. Since the motion field affects the segmentation result and vice versa, an iterative refinement scheme should be adopted. Experimental results have shown that the proposed motion compensation scheme based on the RCWP provides a better performance than the conventional motion compensation schemes.

This paper proposes the recovery technique of blurred video signals using the new regularized constrained iterative image restoration (RCIIR) algorithm, which is combined with motion estimation. We enhanced the subjective video quality and improved the resolution of video signals by applying the new RCIIR algorithm, which had been developed with blurred still images, to the moving objects in the video sequences. Based on the extracted motion information of moving objects from the motion estimation technique, we could obtain the approximated point spread function, which was modelled as uniform motion blur. We then applied the RCIIR algorithm to the blurred moving objects so that we could improve the resolution and quality of the videos. The experimental results showed that the boundaries of blurred objects became clearer and the overall subjective quality of the restored video sequences was improved. Our proposed recovery technique was suitable to enhance degraded video signals due to motion blurs and it was applicable to non-real time video processing to enhance the subjective quality and resolution.

In Huffman coding of multiple sources with a constrained memory, determination of Huffman parameters has a great effect on coding performance. This letter presents an efficient method for determining the Huffman parameters, which can be applied to many high-order entropy coding systems with memory constraints.

Motion vector field is generally encoded by using an intraframe differential coding, that is, the well known DPCM approach. An interframe differential coding might be an alternative when the motion vector field is not spatially smooth enough. In this paper, we propose a multistage interframe differential coding approach. In addition to the temporal dependencies between the motion vector fields, temporal dependencies between residual vector fields of consecutive stages are also exploited in this approach. An accumulated average for generating the compensation vector field is also proposed in this paper. Experimental results have shown that the proposed approach is more suitable for real applications where various characteristics of motion fields might exist.

This paper proposes a new regularized constrained iterative image restoration algorithms which applies three new space-adaptive methods to a degraded image, and analyze the convergence condition of the proposed algorithm. First, we introduce space-adaptive regularization operators which change according to edge characteristics of local images in order to effectively preserve edges and boundaries in the restored images. Second, an adaptive noise reduction filter is applied on the plain regions so that salt-pepper phenomenon which results from noise amplification can be eliminated effectively. Finally, a pseudo projection operator is used to reduce the ringing artifact. And the proposed algorithm adopts momentum in the steepest descent formulation, which improves the convergence performance both in the speed and accuracy. According to the experimental results for various signal-to-noise ratios (SNR), the proposed image restoration algorithm outperforms other methods and is robust to noise effects and edge reblurring by regularization especially.

A new transform domain vector quantizer has been introduced for efficient image coding which employs directional decomposition and sequential vector quantization of DCT coefficients (DCT-SVQ): the DCT coefficients are decomposed into 16 slightly-overlapping subvectors for a subvector to convey key information about one directional image, and then the decomposed subvectors are vector quantized sequentially. The scheme has the capability of the rate control with no need for changing the codebooks and reveals good performance over a wide range of code rates. This paper addresses the improvement of that scheme by (1) adjusting the quantization step size of the DC quantizer as well as the AC quantizers according to the target distortion of the reconstructed image and (2) introducing the activity of an image block to the decision of the appropriate stopping condition of the sequential vector quantizer for that block.>

In this paper, we propose a video composition method based on a robust estimation of camera parameters from image sequence. The proposed method is based on an investigation that any camera operation containing a change of scale and a pure 3D rotation can be represented by a 2D geometric transformation. The transformation can explain all the video composition procedure consisting of locating, synchronizing, and operating images. The parameters in the image transformation are estimated from image sequence. The estimation scheme consists of first establishing correspondence and then estimating the parameters by fitting the correspondence data to the transformation model. A robust algorithm based on rejection of outliers is proposed for reliable parameter estimation. Experimental results support the validity of the estimation method.>

This paper describes the implementation of absolute moment block truncation coding (AMBTC) in real time for the moving picture data compression. Using the AMBTC algorithm, we have realized and operated a system for an NTSC TV signal and obtained quite an excellent performance. All circuits are implemented in the wrapping method, and the highest processing clock rate is 10.7 MHz (3 fsc). The sampling rate is 5.35 MHz. The system implemented by hardwares excluding software manipulation, which contains five subblocks performs well to get the compressed data rate of 2.0 bits/pel. The quality of the processed picture is more or less degraded but not objectionable.

This concise paper presents the realization of a 90°constant phase shifter in the VHF band, which is entirely different from the conventional method for the realization of constant phase shifters in the audio frequency range. The construction of the 90° constant phase shifter is simple and can be easily realized by using a transmission line, and the lumped constant elements, R, L, C. Experimental verification is included.

When the ratio of the frequency of the carrier to that of the modulating signal becomes less than approximately 10:1, AM detectors become unable to detect the impressed modulation in a satisfactory manner. Distortion due to transient charging and discharging phenomena in the diode circuit during detection of wide-band AM signals has imposed limitations on channel capacity in AM and FM wide-band multiplexing systems. This paper presents and analyzes polyphase envelope detection as a suitable method of solving the problem. This technique makes it possible to detect the envelope of the impressed AM signal to any desired degree of accuracy even when the ratio of the frequency of the carrier to that of the modulating signal approaches unity. The paper shows the results of an experiment that was carried out to verify the theory.