Su Fulin

Feature extraction and selection based on ATR of ISAR image

In this paper, based on auto target recognition (ATR), two kind of feature in ISAR images are extracted: Fourier-transform coefficients feature and wavelet-transform coefficients feature. Three kinds of targets ISAR images were done some recognition study based on the exact nearest neighbor algorithm and those extracted features. Experimental results show these two methods are effective.

Improvements on the range alignment of the motion compensation for ISAR imaging

This paper describes a motion compensation method (range profile correlation alignment and phase alignment) for inverse synthetic aperture radar imaging and presents two improvements on this method. The imaging results show these improvements are very effective.

Research on observation of slight debris in space via space-based imaging radar

Propose a plan of slight space debris observation via space-based imaging radar system previously designed. Based on the idea of differential orbit scan, the investigation focuses on the analyses of orbital scanning period, space area segmentation, radar parameters design and echoes record. In order to cope with weak signals detection, pulse accumulated arithmetic is considered. But because of the relative motion between observation platform and space object as well as the perturbations effected by other forces in space, the signal position in different echoes is dithering. Therefore, three kinds of correlated detection methods are proposed to adjust multiple group echoes. Simulations give the correction results of these methods and then through comparison, the maximum correlation and subsection correlation algorithms are chosen to be applied on the detection of different space environment.

An algorithm of bridge detection in radar sensing images based on fractal

This paper presents a new method to detect bridges in Synthetic Aperture Radar (SAR) images based on fractals. In this method, the gray surface of an SAR image is modelled as a DFBR (Discrete Fractional Brownian Random) field. In the homogenous region of SAR image, the H (Hurst) exponent of the DBFR is about the same; but in the sharply changing region such as the boundaries of a bridge, the H occurs singularity. According by this characteristic, the bridge can be detected and extracted. In order to alleviate the influence of the speckle of SAR image, the concept of mean was introduced into this algorithm. Experiment results show this algorithm is very effective and superior to other classical edge detection operators.

A speckle reduction algorithm for SAR images

In this paper, we propose a speckle reduction algorithm for radar images based on the wavelet transform. First, the logarithmic transform is applied to the original image to convert the multiplicative noise model into an additive Gaussian noise model. Then multiscale wavelet decomposition is used to obtain pyramidal-structured subimages. A direction-dependent mask is used to identify the edges in the detail images in wavelet subspaces. These subimages are processed by reducing the amplitude of the wavelet coefficients in the detail images and releasing the amplitude where are judged edges, so that speckles are suppressed and edges are preserved. Finally, the wavelet reconstruction and exponential transformation are applied to the processed subimages and the despeckled output image is obtained. The experimental results with a JERS-1 image show that the proposed algorithm is effective in both speckle reduction and edge preservation.

Robust image watermarking research based on DCT transform

Digital watermarking has been proposed as a solution to the problem of copyright protection of multimedia data. But, most watermarking methods, especially the ones based on the frequency domain, can not satisfy the robustness requirement of some geometry attacks such as cropping and so on. To get around this problem, in this paper we proposed a new algorithm based on the DCT field which uses some specially-designed techniques. Experimental results demonstrate that the watermark algorithm we propose is really very robust to cropping attack and other signal processing including JPEG compression, addition of noise etc.

Widely Linear Quaternion Unscented Kalman Filter for Quaternion-Valued Feedforward Neural Network

Recently, the quaternion-valued feedforward neural network (QFNN) has been developed to process three dimensional (3-D) and 4-D signals in quaternion domain, and the weight matrices and bias vectors of the QFNN were obtained based on the quaternion backward propagation (QBP) method. However, it should be noted that the QBP is a first-order quaternion gradient descent algorithm. The convergence speed of the QBP is usually slow and may not be very suitable to process nonstationary quaternion-valued signals. To address this problem, a widely linear quaternion unscented Kalman filter (WLQUKF) algorithm is proposed to train the QFNN. This is derived by utilizing some recent studies in the augmented quaternion statistics and the

An algorithm of bridge detection in remote sensing images based on fractal

\mathbb {HR}

The system compensation of isar

-calculus. With the augmented quaternion statistics, the WLQUKF is able to process general quaternion-valued noncircular, nonlinear, and nonstationary signals, effectively. Simulations on both benchmark circular and noncircular quaternion-valued signals, and on real-world quaternion-valued signals support the analysis.

Optimum imaging time selection algorithm for inverse synthetic aperture radar images using geometric features and image gradient

This paper presents a new method to detect the bridge in synthetic aperture radar (SAR) images based on fractal. In this method, the gray surface of SAR image is model as a DFBR (discrete fractional Brownian random) field. In the homogenous region of SAR image, the H (Hurst) exponent of DHFR is almost the same but in the sharply change region such as the boundaries of bridge, the H occurs as singularity. According to this characteristic, the bridge can be detected and extracted. In order to alleviate the influence of the speckle of SAR image, an idea of mean was introduced into this algorithm. Experiment results show this algorithm is very effective and superior to other classical edge detection operators.