IEE Proceedings: Vision, Image and Signal Processing

A simple and efficient method for system identification even at a very low signal-to-noise ratio (SNR) is presented. At an SNR as low as −7.5 dB, noise dominates the spectrum and system poles are almost lost in the profound noise. In the proposed method, an enhanced spectrum is estimated in the discrete cosine transform (DCT) domain using the least squares curve-fitting technique. The system modes that were previously indistinguishable become prominent in the enhanced spectrum. The system order is then overestimated using least squares higher order Yule–Walker (LSHOYW) equations to obtain better accuracy. The poles having higher strength in the autocorrelation domain are then identified as system poles.

A.T. Connie

F. Ferdousi

M. Sharmin

M.R. Khan

IEE Proceedings - Vision Image and Signal Processing

Identification of AR parameters at a very low SNR using estimated spectral distribution in DCT domain

在DCT域中利用估计的频谱分布识别极低信噪比下的AR参数

Data clustering in kernel-induced feature space is interesting in that, by nonlinearly mapping the observed data from a low-dimensional input space into a high (possibly infinite)-dimensional feature space by means of a given kernel function, the kernel-based clustering can reveal complicated (e.g. linearly nonseparable) data structures that may be missed by traditional clustering methods in the standard Euclidean space. A kernel-based deterministic annealing (KDA) algorithm is developed for data clustering by using a Gaussian kernel function. The Gaussian parameter (width), which determines the nonlinear mapping together with the Gaussian kernel, is adaptively selected by the scaled inverse of data covariance. The effectiveness of the Gaussian parameter (width) selection method and the superiority of the KDA algorithm for clustering a variety of data structures are supported by the experimental results on artificial and real data sets.

X.L. Yang

Q. Song

W.B. Zhang

Kernel-based deterministic annealing algorithm for data clustering

基于核的确定性退火算法用于数据聚类

The pointwise sampling algorithm has been used in adaptive contrast enhancement (ACE) for nearly three decades. To overcome its computational overhead, various stepwise sampling algorithms have been proposed, including the highly overlapped interpolation contrast enhancement (HOICE) algorithm that addresses the artefacts, such as image distortion and blocking effects, of other stepwise sampling algorithms while keeping the advantage of speed. However, HOICE&apos;s internal mechanism has not been compared with traditional pointwise algorithms, which may affect the scope of its future application. The authors establish a bridge between traditional pointwise sampling and HOICE: they first mathematically analyse the internal mechanism of two typical sampling algorithms (pointwise and HOICE); and then quantitatively demonstrate the similarities between these two kinds of algorithms. Moreover, the results of quantitative measurement suggest that HOICE has an advantage over the pointwise algorithm in reducing the distortion along image edges. Therefore HOICE has the advantages of both pointwise and other stepwise algorithms making it a reliable sampling algorithm for ACE.

Z.Q. Wu

J.A. Ware

I.D. Wilson

J. Zhang

Mechanism analysis of highly overlapped interpolation contrast enhancement

高重叠插值对比度增强的机制分析

The stability issue in adaptive notch filters is investigated from a structural viewpoint. A new adaptive algorithm for direct frequency estimation is developed using a constrained pole-zero notch filter. The basic characteristic of this algorithm is that the notch filter is realised in a cascade form, with each stage implemented in a normal realisation. A simplified version of the gradient signals is derived, which makes the algorithm very efficient. It is shown that this proposed adaptive notch filter is bounded-input–bounded-output stable. Numerical examples with simulations, where the proposed algorithm performs well in terms of convergence and guaranteed stability, are given to support the theoretical results.

J. Zhou

Simplified adaptive algorithm for constrained notch filters with guaranteed stability

约束陷波滤波器的简化自适应算法及其稳定性保证

A new analytic method for estimating the pose of a calibrated camera from a single view of a planar target with a known geometry is presented. A set of fiducial points is extracted from an image of this target and metrically rectified through a 2D homography. The author&apos;s contribution consists in deriving from the coefficients of this transformation the analytic expressions of the 3D rigid motion parameters defining the pose of the camera. Experiments with synthetic data show the effectiveness of the proposed method against another gold-standard method for pose estimation and its robustness against perturbations of the fiducial points. These features make the algorithm a perfect candidate for all those applications where pose estimation has to be performed reliably and in real time.

L. Lucchese

Closed-form pose estimation from metric rectification of coplanar points

从共面点度量矫正的闭式姿态估计

Publication Information	Publisher: Institute of Electrical Engineers，Publishing cycle: ，Journal Type: journal，Open Access Journals: No
Basic data	Year of publication: 1994，Proportion of original research papers: ，Self Citation Rate:， Gold OA Rate:

IEE Proceedings: Vision, Image and Signal Processing

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Identification of AR parameters at a very low SNR using estimated spectral distribution in DCT domain

Kernel-based deterministic annealing algorithm for data clustering

Mechanism analysis of highly overlapped interpolation contrast enhancement

Simplified adaptive algorithm for constrained notch filters with guaranteed stability

Closed-form pose estimation from metric rectification of coplanar points

Identification of AR parameters at a very low SNR using estimated spectral distribution in DCT domain

Kernel-based deterministic annealing algorithm for data clustering

Mechanism analysis of highly overlapped interpolation contrast enhancement

Simplified adaptive algorithm for constrained notch filters with guaranteed stability

Closed-form pose estimation from metric rectification of coplanar points