iosr-JVSP   Volume-1 ~ Issue-2

ABSTRACT:We propose a new technique for digital image restoration, in this the noise free and noisy pixels are classified based on empirical multiple threshold values. Then the median filtering technique is applied. So that noise free pixels are getting preserved and only noisy pixels get restored. A novel decision-based filter, called the multiple thresholds switching (MTS) filter, is used to restore images corrupted by salt-pepper impulse noise. The filter is based on a detection-estimation strategy. At high noise densities, their performance is poor. A new algorithm to remove high-density salt and pepper noise using modified Decision Based Unsymmetric Trimmed Median Filter (DBUTMF) is proposed. When all the pixel values are 0's and 255's then the noise pixel is replaced by mean value of all the elements present in the selected window. The performance of our proposed algorithm will be analyzed based PSNR and MSE values.
Keywords:Median filter, salt and pepper noise, unsymmetrical trimmed median filter

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ABSTRACT:Image compression plays an important role in the compression of medical images. Medical imagings are mainly used for diagnosis of diseases and surgical planning. Medical images are usually stored digitally. Medical Image compression plays an important role in telematics especially in telemedicine. It is necessary that medical images need to be compressed for reliability to be transmitted. In the medical image compression diagnosis is effective only when the compressed image preserves all the information of the original image. This results in a lossless compression technique. While lossy compression techniques, are more efficient in terms of storage and transmission needs but there is no warranty that they can preserve the characteristics needed in medical image processing and diagnosis. Compression plays an important role as medical imaging moves to film less imaging.CTI or MRI medical imaging are used nowadays which can produce pictures of the human body in digital form. The lifting scheme is used for the design of both orthogonal and bi-orthogonal filters .It is implemented for the orthogonal filters using two lifting steps .The performance of the proposed filters are then compared with the conventional filters in terms of compression ratio, PSNR etc. The bi-orthogonal filters are implemented using the SPIHT algorithm replacing the EZW coding for image compression. SPIHT algorithm requires fewer bits to capture the same amount of information when compared with EZW proposed.
Keywords: Bi-orthogonal wavelet transforms, Lifting scheme, SPIHT algorithm, EZW coding, orthogonal filters.

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ABSTRACT:In this paper, a scheme for the design of pipeline architecture for a real-time computation of the 2- D DCT has been presented. The objective has been to achieve a low computation time by maximizing the operational frequency and minimizing the number of clock cycles required for the DCT computation, which, in turn, have been realized by developing a scheme for enhanced inter- and intra stage parallelisms for the pipeline architecture. it is most efficient to map the overall task of the DCT computation to only two pipeline stages, i.e., one for performing the task of the level-1DCT computation and the other for performing that of all the remaining decomposition levels. In view of the fact that the amount and nature of the computation performed by the two stages are the same, their internal designs ought to be the same. There are two main ideas that have been employed for the internal design of each stage in order to enhance the intra stage parallelism. The first idea is to decompose the filtering operation into two subtasks that operate independently on the evenand odd-numbered input samples, respectively. This idea stems from the fact that the DCT computation is a twosub band filtering operation, and for each consecutive decomposition level, the input data are decimated by a factor of two.
Keywords: DCT, Pipeline Architecture, 2-D DCT, Intra Stage Parallelisms, Filtering

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