序列图像运动点目标快速检测与跟踪方法

为解决低信噪比运动点目标在实时检测中的系统抖动和信噪比低等问题,根据运动点目标的特点,提出了基于数学形态学滤波、目标光强度连续性和假设检验的点目标检测方法。基于数学形态学的高通滤波器能较强地抑制背景噪声并增强目标;利用光强度时空连续性识别目标;假设检验对解决目标丢失和新目标出现都具有较好的效果。用TMS320C6201高速信号处理器的处理结果表明：算法对信噪比约为2的点目标检测性能较为满意。     

A class of distortionless codes designed by Bayes decision theory

The problem of distortionless encoding when the parameters of the probabilistic model of a source are unknown is considered from a statistical decision theory point of view. A class of predictive and nonpredictive codes is proposed that are optimal within this framework. Specifically, it is shown that the codeword length of the proposed predictive code coincides with that of the proposed nonpredictive code for any source sequence. A bound for the redundancy for universal coding is given in terms of the supremum of the Bayes risk. If this supremum exists, then there exists a minimax code whose mean code length approaches it in the proposed class of codes, and the minimax code is given by the Bayes solution relative to the prior distribution of the source parameters that maximizes the Bayes risk     

一种新的红外序列图像运动小目标分割算法

红外序列图像运动小目标检测技术,是红外搜索与跟踪系统的一项核心技术,也是现代研究领域的一大难题。本文提出了一种新的红外序列图像运动小目标分割算法,算法运用边界跟踪理论进行图像分割,并与传统的阈值分割算法进行效果比较。大量的实验结果表明,此新的算法能取得更好的小目标分割效果。     

Spatio-temporal visibility function for image sequences

The conventional visibility function of a still image is extended to a spatio-temporal visibility function for image sequences. The visibility of impairment noise is subjectively measured as a function of both spatial and temporal gradients by an A/B sequence test. Some characteristics of the spatio-temporal visibility function are presented such as approximated forms and comparisons with spatial visibility functions.<>     

A Bayes sequential test of m hypotheses (Corresp.)

The problem of sequentially deciding upon one ofmmutually exclusive and exhaustive hypotheses has been studied in detail for the case ofm = 2. This correspondence presents the structure for the Bayesm-ary sequential detector. Computational results depend on a property called subspace separability, which allows one to reduce the dimensionality of the essential averaging process. Numerical results are presented for the case of Gaussian observation statistics andm = 3.     

红外图像序列的目标增强和检测

文中主要研究了远距离红外图像序列的目标增强和检测问题,提出了基于局部纹理特征的红外图像增强算法,利用红外图像目标和背景区域局部纹理特征的差异来增强目标和背景区域的对比度;为了提高目标检测的速度和精度,利用序列图像的帧间相关信息,采用边检测边跟踪边确认的目标检测方法。实验结果表明,对于远距离、小目标的红外图像,这种增强算法在目标对比度和细节方面都明显优于直方图均衡化方法,而本文采用的目标检测方法仅需很少几帧图像就能检测和跟踪目标,可以在确保目标检测的可靠性的前提下,提高目标的检测速度。     

Halftone image classification using LMS algorithm and naive Bayes

Former research on inverse halftoning most focus on developing a general-purpose method for all types of halftone patterns, such as error diffusion, ordered dithering, etc., while fail to consider the natural discrepancies among various halftoning methods. To achieve optimal image quality for each halftoning method, the classification of halftone images is highly demanded. This study employed the least mean-square filter for improving the robustness of the extracted features, and employed the naive Bayes classifier to verify all the extracted features for classification. Nine of the most well-known halftoning methods were involved for testing. The experimental results demonstrated that the classification performance can achieve a 100% accuracy rate, and the number of distinguishable halftoning methods is more than that of a former method established by Chang and Yu.     

Estimating motion in image sequences

We have reviewed the estimation of 2D motion from time-varying images, paying particular attention to the underlying models, estimation criteria, and optimization strategies. Several parametric and nonparametric models for the representation of motion vector fields and motion trajectory fields have been discussed. For a given region of support, these models determine the dimensionality of the estimation problem as well as the amount of data that has to be interpreted or transmitted thereafter. Also, the interdependence of motion and image data has been addressed. We have shown that even ideal constraints may not provide a well-defined estimation criterion. Therefore, the data term of an estimation criterion is usually supplemented with a smoothness term that can be expressed explicitly or implicitly via a constraining motion model. We have paid particular attention to the statistical criteria based on Markov random fields. Because the optimization of an estimation criterion typically involves a large number of unknowns, we have presented several fast search strategies     

Bottom-up segmentation of image sequences for coding

A bottom-up segmentation method is presented as a first step of object based coding. An initial partition is created based on connected filters. The iterative fusion algorithm merges the most similar regions until the target is reached. As the regions become bigger, more complex criterion, like similarity of texture or of motion are used. The algorithm offers a good balance between time stability and the ability to cope with the apparition of new regions.     

Three-dimensional parameter estimation from stereo image sequences for model-based image coding

It is shown that the analysis of moving image sequences for 3D modelling can be performed in a relatively straightforward manner if the scene is captured in stereo. Output from a stereo disparity estimation process using calibrated cameras gives absolute 3D surface coordinates from a single stereo pair. When combined with monocular motion cues, the true 3D motion parameters of moving objects can be accurately calculated. Further analysis enables segmentation of body elements according to motion while the 3D surface feature structure, although available from the start, can be integrated and checked for anomalies over the sequence. These results are expected to alleviate the known problems of ambiguity suffered by monocular-source model-based coders.     

Spatio-temporal segmentation of image sequences for object-oriented low bit-rate image coding

This paper describes a new method of segmentation of time-varying image sequences whose goal is object-oriented image coding. The segmentation represents a partition of each frame of the sequence into a set of regions which are homogeneous with regard to motion criterion. The region borders correspond to spatial contours of objects in the frame. Each spatio-temporal region is characterized by its temporal component, which is a model-dependent vector of motion parameters, and a structural component representing the polygonal approximation of the spatial contour of the region.

The construction of spatio-temporal segmentation includes two phases: the initialization step and temporal tracking. The initialization step is based on the spatial segmentation of the first frame of the sequence. Then homogeneous spatial regions are merged through motion estimation in accordance with a motion-based criterion. The temporal tracking consists of the projection of the segmentation along the time axis, and its adjustment. Special attention is paid to the processing of occlusions.

A predictive coding scheme is proposed which is based on the temporal coherence of the segmentation. This scheme is promising for a low bit-rate image compression.

The results for teleconference and TV sequences show the high visual quality of reconstructed only by prediction images. Moreover, the bit-rates for motion coding are very low: from 0.002 to 0.007 bit/pixel for teleconference sequence and from 0.004 to 0.021 bit/pixel for complex TV sequence. A scheme for encoding of the structural information is proposed which requires 0.083 – 0.17 bit per pixel depending on the content of the sequence.     

Image segmentation for compression of images and image sequences

Region-based image coding schemes, the so-called second generation techniques, have gained much favour in recent years. For still picture coding, they can increase the compression ratio obtained by transform coding by an order of magnitude, while maintaining adequate image representation. The success of these techniques relies on the ability to describe regions in an image succinctly by their shape and size. The algorithms presented describe methods for segmenting images. Unlike most other region based algorithms, these algorithms incorporate knowledge of the border coding process in deciding how to partition the image. The extension from single image compression to sequential image compression is also considered. A new, efficient segmentation scheme is proposed that exploits temporal redundancies between successive images, and reduces some problems associated with error accumulation in error images     

Bayesian methods for multiaspect target tracking in image sequences

In this paper, we introduce new algorithms for automatic tracking of multiaspect targets in cluttered image sequences. We depart from the conventional correlation filter/Kalman filter association approach to target tracking and propose instead a nonlinear Bayesian methodology that enables direct tracking from the image sequence incorporating the statistical models for the background clutter, target motion, and target aspect change. Proposed algorithms include 1) a batch hidden Markov model (HMM) smoother and a sequential HMM filter for joint multiframe target detection and tracking and 2) two mixed-state sequential importance sampling trackers based on the sampling/importance resampling (SIR) and the auxiliary particle filtering (APF) techniques. Performance studies show that the proposed algorithms outperform the association of a bank of template correlators and a Kalman filter in adverse scenarios of low target-to-clutter ratio and uncertainty in the true target aspect.     

A novel test circuit for automatically detecting electrochemical migration and conductive anodic filament formation

The rapid growth of the global electronics manufacture environment has brought about the onset of a variety of new, untested materials and processing chemicals. The interactions between substrates and processing chemicals that can occur during manufacture, storage and use must be assessed in order to determine long-term reliability. Surface insulation resistance (SIR) testing is a standard industry technique used to assess the interactions between processing chemicals (e.g., soldering fluxes) and substrates. SIR test method conditions vary in terms of the temperature and the humidity used to accelerate the normal failure modes. Typically, a 45 to 50 volt bias is applied to an interdigitated comb pattern, and periodic SIR measurements are made using a 100 volt test. Pass/fail criteria based solely on SIR electrical values, (e.g., 100 MΩ) however are inadequate. Often the electrical measurement fails to reveal the presence of surface dendrites due to contaminants related to processing chemicals. This failure occurs because the dendrite burns out between electrical readings when the circuit continues to be biased at 50 volts. A new “linear test circuit” has been developed to overcome this deficiency. The circuit uses an operational amplifier to detect the formation of a surface dendrite between electrodes on the comb pattern. When the dendrite shorts the circuit, voltage to the comb pattern is removed. Thus, the presence of the dendrite is captured electrically, and the dendrite is preserved for further analysis. This paper will present the circuit used and data showing its’ effectiveness at detecting both surface dendrites and subsurface conductive anodic filament formation.     

基于Bayes理论的装载可靠度定时截尾试验方案

研究小子样条件下鱼雷装载可靠度Bayes检验方案的制定方法。采用优化方法确定试验方案,克服了传统方法主观性较强的缺点,提高了试验方案的准确性和客观性。应用实例表明,该方法能缩短试验时间,较大地降低了试验成本。     

动态红外图像的建模与仿真技术

讨论了红外场景的动态图像建模与仿真技术,由于目标、背景、大气状态的复杂性,红外图像建模与仿真的难度很大。首先介绍了在SGI工作站环境下,红外图像序列建模和仿真软件的设计思想、实现方法和软件框架。然后分析各种辐射对成像的影响,给出辐射计算公式,分别就无源和有源场景进行了分析,提出无源场景温度的求解方法,说明了场景模型、大气传输模型和材料的物理特性对红外成像的作用。最后给出了建模与仿真的一些实例和综合评价。     

Design of universal test sequences for VLSI

A test sequence is called(s,t)-universal if it exercises every function depending on t or fewer inputs on a very large scale integration (VLSI) chip withsinputs. Randomized and deterministic procedures are deseribed for the design of(s,t)-universal sequences and for the signature analysis of the test outputs.     

图像边缘检测算法的设计和研究

针对经典的边缘检测算法均涉及梯度的运算,存在对噪声敏感、计算量大等缺点的问题,为了找到一种检测效果好、计算量相当的图像边缘算法,提出了只基于对周边像素的灰度比较,完全不涉及梯度运算的SUSAN算法。主要研究了SUSAN算法,并比较了主流的Prewitt算子,Gauss—laplace算子,Canny算子的边缘检测算法,经Matlab仿真实验后,确定该算法不需要计算微分,计算量小,进一步减少了噪声的影响,且SUSAN算子控制参数的选择很简单,任意性较小,所以比较容易实现自动化的选取,是一种非常有效的算法。     

Interpolation of missing data in image sequences

This paper presents a number of model based interpolation schemes tailored to the problem of interpolating missing regions in image sequences. These missing regions may be of arbitrary size and of random, but known, location. This problem occurs regularly with archived film material. The film is abraded or obscured in patches, giving rise to bright and dark flashes, known as "dirt and sparkle" in the motion picture industry. Both 3-D autoregressive models and 3-D Markov random fields are considered in the formulation of the different reconstruction processes. The models act along motion directions estimated using a multiresolution block matching scheme. It is possible to address this sort of impulsive noise suppression problem with median filters, and comparisons with earlier work using multilevel median filters are performed. These comparisons demonstrate the higher reconstruction fidelity of the new interpolators.     

Binocular transfer methods for point-feature tracking of image sequences

Image transfer is a method for projecting a 3D scene from two or more reference images. Typically, the correspondences of target points to be transferred and the reference points must be known over the reference images. We present two new transfer methods that eliminate the target point correspondence requirement. We show that five reference points matched across two reference images are sufficient to linearly resolve transfer under affine projection using two views instead of three views as needed by other techniques. Furthermore, given the correspondences of any four of the five reference points in any other view, we can transfer a target point to a third view from any one of the two original reference views. To improve the robustness of the affine projection method, we incorporate an orthographic camera model. A factorization method is applied to the reference points matched over two reference views. Experiments with real image sequences demonstrate the application of both methods for motion tracking.