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The traditional range Doppler (RD) imaging algorithm has become the most intuitive and classical method in synthetic aperture radar (SAR) imaging processing because of its easy implementation and high processing efficiency. However, owing to the poor quality of the image produced by RD algorithm, this traditional imaging method is growing increasingly unable to meet practical needs. In an effort to solve the problem of poor azimuth imaging quality, this study proposes a high-resolution RD azimuth imaging algorithm. The expression of the optimal order of the SAR azimuth signals using fractional Fourier transform (FrFT) is derived in detail herein. A theoretical analysis shows that this optimal order is unique and depends on the azimuth imaging parameters. The experimental results based on airborne SAR simulation data and spaceborne SAR measurement data indicate that the azimuth resolution of the proposed algorithm is improved by 31.6 or 46.8% as against that of the traditional RD algorithm, whereas the peak side lobe ratio (PSLR) and integrated side lobe ratio (ISLR) values obtained via the proposed algorithm are approximately equivalent to those obtained via the traditional RD algorithm.

Fault recognition is an important section in seismic interpretation and there are many methods for this technology, but no one can recognize fault exactly enough. For this problem, we proposed a new fault recognition method based on ant colony optimization which can locate fault precisely and extract fault from the seismic section. Firstly, seismic horizons are extracted by the connected component labeling algorithm; secondly, the fault location are decided according to the horizontal endpoints of each horizon; thirdly, the whole seismic section is divided into several rectangular blocks and the top and bottom endpoints of each rectangular block are considered as the nest and food respectively for the ant colony optimization algorithm. Besides that, the positive section is taken as an actual three dimensional terrain by using the seismic amplitude as a height. After that, the optimal route from nest to food calculated by the ant colony in each block is judged as a fault. Finally, extensive comparative tests were performed on the real seismic data. Availability and advancement of the proposed method were validated by the experimental results.

Histogram specification is a useful algorithm of image enhancement field. This paper proposes an image haze removal algorithm of histogram specification based on the weighted Gaussian probability density function (Gaussian PDF). Firstly, we consider the characteristics of image histogram that captured when sunny, fogging and haze weather. Then, we solve the weak intensity of image specification through changing the variance and weighted Gaussian PDF. The performance of the algorithm could removal the effective of fog and experimental results show the superiority of the proposed algorithm compared with histogram specification. It also has much advantage in respect of low computational complexity, high efficiency, no manual intervention.

An improved ellipse detection algorithm based on least square approach was proposed to enhance the efficiency and accuracy of ellipse detection in digital images. The algorithm get ellipses by lease square based every boundary that obtained by the image edge detection operator. Then, we filter the ellipse by the fitting rate, ellipticity and area of the ellipse. Finally, the compared experiment results indicate that the improved method reduce the time consumption. Application of the algorithm verified the feasibility and effectiveness of the method in the actual image that can fit ellipse with high precision and meter of substation, which can also effectively deal with the extraction of region of ellipse in the image.

A blind source separation algorithm by the accurate diagonalization of second-order statistics is presented for the mixed speech-noise signals. The new algorithm uses the autocorrelation covariance matrix and its one-sample delayed counterpart of the two prewhitened noisy data and forms two 2×2 positive definite symmetry matrices pencil. A tangent algorithm for computing the generalized singular value decomposition is then exploited for simultaneously diagonalizing these two matrices accurately, and its theoretic proof is also presented. Compared with JADE algorithm and SOBI algorithm, the new algorithm is of simple computation and more computation precision. And it overcomes the limitations of their both incapable accurate diagonalization for fourth-order cumulant matrices and time-delayed covariance matrices, separately. Under the conditions of white Gaussian and colored noise, computer simulation results show that the performance of the new algorithm separating speech from noisy data is superior to those of JADE algorithm and SOBI algorithm.

In this paper, we investigate a new blind source separation algorithm for TITO (two-input and two-output) channel system. Considering the case of the noisy instantaneous linear mixture of source signals, we form the matrix pair with the two 2×2 dimension symmetric, positive definite matrices via two covariance matrices. We apply a set of transforms such as the Cholesky factorization and SVD (singular value decomposition) to this formed matrix pair. And a unitary matrix is then obtained, which is an accurate diagonalizer of each matrix of this pair. Compared with the JADE algorithm and the SOBI algorithm, some numerical results show the better performance of the new algorithm.

In this paper we introduce a method for trace interpolation using wavelet transform(WT). According to WT, the approximation of a function at resolution can be gotten by transforming inversely the approximation and detail at resolution Suppose the detail at resolution 1 is negligible or can be estimated , the approximation at resolution 2 will be obtained from original function. Based on this point, two methods of trace interpolation are provided. One neglects the detail at resolution 1, that is space alias is not considered. The other estimates the detail. Tests showed that these two method ‘are effective.