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Electrical impedance tomography (EIT) is a new computer tomography technology, which reconstructs an impedance (resistivity, conductivity) distribution, or change of impedance, by making voltage and current measurements on the object's periphery. Image reconstruction in EIT is an ill-posed, non-linear inverse problem. A method for finding the place of impedance change in EIT is proposed in this paper, in which a multilevel BP neural network (MBPNN) is used to express the non-linear relation between the 相似文献
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A new improved Goh's 3-D wavelet transform(WT) coding scheme is presented in this paper. The new scheme has great advantages including a simple code structure, low computation cost and good performance in PSNR, compression ratios and visual quality of reconstructions, when compared to the other existing 3-D WT coding methods and the 2-D WT-based coding methods. The new 3-D WT coding scheme is suitable for very low bit-rate video coding. 相似文献
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1 Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｔｈｅｉｍａｇｅｌｏｓｓｌｅｓｓｃｏｍｐｒｅｓｓｉｏｎｃｏｄｉｎｇｉｓａｎｉｍｐｏｒｔａｎｔｐａｒｔｏｆｔｈｅｄｉｇｉｔａｌｉｍａｇｅｃｏｍｐｒｅｓｓｉｏｎｒｅｓｅａｒｃｈ .Ｍｅｄｉｃａｌｉｍａｇｅｓ,ｓａｔｅｌｌｉｔｅｉｍａｇｅｓａｎｄｓｅｉｓｍｉｃｄａｔａｄｅｍａｎｄｌｏｓｓ ｌｅｓｓｃｏｄｉｎｇ .Ｔｈｅｂａｓｉｃｉｄｅａｏｆｃｏｍｐｒｅｓｓｉｏｎｉｓｔｏｅｘｐｌｏｉｔｔｈｅｃｏｒｒｅｌａｔｉｏｎｓｔｒｕｃｔｕｒｅｐｒｅｓｅｎｔｅｄｉｎｍｏｓｔｒｅａｌｌｉｆｅｉｍ … 相似文献
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Image reconstruction in elecrical impedance tomography(EIT)is a highly ill-posed inverse problem,Regularization techniques must be used in order to solve the problem,In this paper,a new regularization method based on the spatial filtering theory is proposed.The new regularized reconstruction for EIT is independent of the estimation of impedance distribution,so it can be implemented more easily than the maxiumum a posteriori(MAP) method.The regularization level in our proposed method varies spatially so as to be suited to the correlation character of the object‘s impedance distribution.We implemented our regularization method with two dimensional computer simulations.The experimental results indicate that the quality of the reconstructed impedance images with the descibed regularization method based on spatial filtering theory is better than that with Tikhonov method. 相似文献
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In electrical impedance tomography (EIT) an approximation for the internal resistivity distribution is computed based on the
knowledge of the injected currents and measured voltages on the surface of the body. Several difficulties have been identified in EIT, where
the main problem is the low spatial resolution. This paper presents a fining mesh method based on finite element method (FEM), by fining
the sensitive element, the most actual signal is obtained in certain electrode number. Newton-Raphson reconstruction algorithm improves the
spatial solution of image. The advantages of this method are the improvement of spatial resolution and ease of implementation. 相似文献
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We have constructed a compactly supported biorthogonal wavelet that approximates the modulation transfer function(MTF) of human visual system in the frequency domain.In this paper,we evaluate performance of the constructed wavelet,and compare it with the widely used Daubechies9-7,Daubechies 9-3 and GBCW-9-7 wavelets.The result shows that coding performance of the constructed wavelet is better than Daubechies9-3,and is competitive with Daubechies 9-7 and GBCW-9-7 wavelets.Like Dauechies 9-3 wavelet,the filter coefficients of the constructed waveklet are all dyadic fractions,and the tap is less than Daubechies 9-7 and GBOW 9-7,It has an attractive feature in the realization of discrete wavelet transform. 相似文献
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In this paper, a kind of practical image segmentation algorithm for segment characters from car license plate is presented, based on
morphology and labeling. First, by morphological operation, noise in the binary image of license plate can be greatly decreased. Then, by
labeling, each connected pixel component is given a unique label. Finally, by the known data of license plate, each character is extracted
correctly. The advantage of this method is that it can deal with plates with different sizes and connected characters plates, and inclined plates.
The experiment results show that it is an effective way to extract characters from the license plate, and can be put into practical use. 相似文献
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