基于模糊判别的立体匹配算法

立体视觉一直是计算机视觉领域所研究的一个中心问题,而立体匹配则是立体视觉技术中最关键也是最困难的部分,就得到适用于基于图象绘制技术中视图合成的准确、高密度视差图（Disparity Map）而言,现有的一些方法存在一定的局限性。考虑到立体匹配过程中存在的不确定性和模糊性,本文将已获得广泛应用的模糊理论引入立体匹配领域,提出了基于模糊判别的立体匹配算法,并用实际图象与合成图象进行了实验验证,结果表明该算法效果良好,具有实用价值。     

Scanning electron microscope-based stereo analysis

In this paper we present a novel technique to analyze stereo images generated from a SEM. The two main features of this technique are that it uses a binary linear programming approach to set up and solve the correspondence problem and that it uses constraints based on the physics of SEM image formation. Binary linear programming is a powerful tool with which to tackle constrained optimization problems, especially in cases that involve matching between one data set and another. We have also analyzed the process of SEM image formation, and present constraints that are useful in solving the stereo correspondence problem. This technique has been tested on many images. Results for a few wafers are included here.     

Case study: stereo vision experiments with multi-core software API on embedded MPSoC environments

Markov random field models provide a robust formulation of low-level vision problems. Among all these problems, stereo vision remains the most investigated field. The belief propagation (BP) method provides accurate result in stereo vision problems. However, the algorithm remains slow for practical use. This paper describes a case study on the parallelization of belief propagation for stereo matching using the ??Multi-core Software APIs?? (MSA) on embedded MPSoC environments. MSA is a library-based middleware providing an asynchronous remote procedure call (RPC) mechanism. It supplies a function-offloading programming model to hide the underlying interprocessor communication and configuration detail from programmers. Furthermore, MSA provides a set of stream-specific APIs for supporting a streaming-function remoting mechanism on heterogeneous multi-core architectures. Our experiments shows that the BP method for stereo matching can be adapted from a single core program to a multi-core one for embedded MPSoC environments rapidly.     

Improving Border Localization of Multi-Baseline Stereo Using Border-Cut

This paper presents a novel algorithm that improves the localization of disparity discontinuities of disparity maps obtained by multi-baseline stereo. Rather than associating a disparity label to every pixel of a disparity map, it associates a position to every disparity discontinuity. This formulation allows us to find an approximate solution to a 2D labeling problem with robust smoothing term by minimizing multiple 1D problems, thus making possible the use of dynamic programming. Dynamic programming allows the efficient computation of the visibility of most of the cameras during the minimization. The proposed algorithm is not a stereo matcher on it own since it requires an initial disparity map. Nevertheless, it is a very effective way of improving the border localization of disparity maps obtained from a large class of stereo matchers. Whilst the proposed minimization strategy is particularly suitable for stereo with occlusion, it may be used for other labeling problems.     

The current state of control loop performance monitoring – A survey of application in industry

Control loop performance monitoring (CPM) in industrial production processes is an established area of research for which many methods to detect malfunctioning loops have been developed. However, it is unclear which methods are successful in an industrial environment. Often, there are additional aspects such as organizational issues, data availability and access that can compromise the use of CPM. In this paper, we are reporting on the results of a survey amongst CPM users. The survey takes stock of existing methods and their use in industry as well as which faults are most frequent and can be detected. Organizational as well as implementation issues are investigated and discussed. This paper aims to identify open research topics and the direction of development of CPM in industrial production processes.     

基于区域边界约束和图割优化的稠密匹配算法

基于图割全局优化的稠密匹配算法中,平滑项表示和遮挡处理是关键问题.具有凸性平滑项的能量函数可以求得全局最优解,但所求结果在视差跳变处过于平滑;而具有非凸平滑项的能量函数虽保留了视差的非连续性,但目前只能使用循环算法求得次优解.为此,基于"视差跳变绝大部分发生在颜色的不连续处"这一设定,提出一种利用区域边界和边界像素间的约束构建能量函数的稠密匹配表示方法,使得该函数既能求得全局最优解,又能使最终结果满足平滑项的"非连续保留"性,且体现遮挡约束、顺序性约束,并显著提高计算效率,在速度和效果上取得较好平衡.     

射线图像的立体匹配技术研究

在数字射线成像检测技术中,当物体形状不适宜于旋转扫描时,传统的X射线计算机断层成像技术(CT)难以得到其3维信息,对于这种情况,立体视觉是一种较好的解决方案。立体视觉的关键技术是立体匹配,尽管目前立体匹配技术的研究已取得了很大的进展,然而这类研究主要局限于可见光等反射成像领域,对X射线图像等透射成像领域的研究很少。由于成像原理的不同,透射图像的立体匹配技术与可见光图像存在很大差异。为了对X射线图像进行正确匹配,根据射线图像的特点,首先制定了合理的立体匹配策略,并指出边缘是一种"好"的匹配基元;然后建立了射线图像立体匹配的约束条件,同时分析了射线图像匹配不确定性的原因;最后确定了由粗到精的两步匹配方法,并提出利用多目视觉约束来实现精匹配。利用工业射线像增强器系统对标准样件进行成像的实验结果表明,该技术是可行的,匹配的绝对平均误差在2pixels范围内。     

Digital library information-technology infrastructures

This paper charts a research agenda on systems-oriented issues in digital libraries. It focuses on the most central and generic system issues, including system architecture, user-level functionality, and the overall operational environment. With respect to user-level functionality, in particular, it abstracts the overall information lifecycle in digital libraries to five major stages and identifies key research problems that require solution in each stage. Finally, it recommends an explicit set of activities that would help achieve the research goals outlined and identifies several dimensions along which progress of the digital library field can be evaluated.     

Efficient Belief Propagation for Early Vision

Markov random field models provide a robust and unified framework for early vision problems such as stereo and image restoration. Inference algorithms based on graph cuts and belief propagation have been found to yield accurate results, but despite recent advances are often too slow for practical use. In this paper we present some algorithmic techniques that substantially improve the running time of the loopy belief propagation approach. One of the techniques reduces the complexity of the inference algorithm to be linear rather than quadratic in the number of possible labels for each pixel, which is important for problems such as image restoration that have a large label set. Another technique speeds up and reduces the memory requirements of belief propagation on grid graphs. A third technique is a multi-grid method that makes it possible to obtain good results with a small fixed number of message passing iterations, independent of the size of the input images. Taken together these techniques speed up the standard algorithm by several orders of magnitude. In practice we obtain results that are as accurate as those of other global methods (e.g., using the Middlebury stereo benchmark) while being nearly as fast as purely local methods.     

传导矛盾问题的成因及解决方法

由于目前还没有对传导矛盾问题的成因进行过深入剖析,所以无法给出有效的解决方案.为解决此问题,定义了传导相关度,并通过其找到传导矛盾问题的根本成因,然后将其转化为TRIZ理论中的技术矛盾,再利用矛盾矩阵中的创新理论找到传导矛盾问题的解决方案.应用实例表明了该方法的有效性,为复杂矛盾问题系统中传导矛盾问题的分析和解决提供了参考依据.     

Self-replicating loops: a survey

This article presents a survey of some of the main research on the development of self-replicating loops. The defining feature of these cellular automata is their ability to create identical copies of themselves by constantly executing a set of instructions dynamically stored within their structure. Interest in these structures has grown in recent years as a possible solution to tackle some of the issues relative to the introduction of next-generation molecular-scale electronics.     

基于双序列比对算法的立体图像匹配方法*

在分析现有立体匹配方法的基础上,提出一种基于双序列比对算法的立体图像匹配方法。将立体图像对中同名极线上的像素灰度值看做是一对字符序列,使用基于动态规划思想的双序列比对算法对这些对字符序列进行匹配,以获取立体图像视差。为验证该方法的可行性和适用性,采用人脸立体图像对进行实验。实验结果表明,使用该方法进行立体图像匹配能获得光滑的、稠密的视差图。基于动态规划思想的双序列比对算法能够有效地解决立体图像匹配问题,从而为图像的立体匹配提供了一个实用有效的方法。     

Catadioptric Stereo Using Planar Mirrors

By using mirror reflections of a scene, stereo images can be captured with a single camera (catadioptric stereo). In addition to simplifying data acquisition single camera stereo provides both geometric and radiometric advantages over traditional two camera stereo. In this paper, we discuss the geometry and calibration of catadioptric stereo with two planar mirrors. In particular, we will show that the relative orientation of a catadioptric stereo rig is restricted to the class of planar motions thus reducing the number of external calibration parameters from 6 to 5. Next we derive the epipolar geometry for catadioptric stereo and show that it has 6 degrees of freedom rather than 7 for traditional stereo. Furthermore, we show how focal length can be recovered from a single catadioptric image solely from a set of stereo correspondences. To test the accuracy of the calibration we present a comparison to Tsai camera calibration and we measure the quality of Euclidean reconstruction. In addition, we will describe a real-time system which demonstrates the viability of stereo with mirrors as an alternative to traditional two camera stereo.     

Multi-view stereo in the Deep Learning Era: A comprehensive review

Multi-view stereo infers the 3D geometry from a set of images captured from several known positions and viewpoints. It is one of the most important components of 3D reconstruction. Recently, deep learning has been increasingly used to solve several 3D vision problems due to the predominating performance, including the multi-view stereo problem. This paper presents a comprehensive review, covering recent deep learning methods for multi-view stereo. These methods are mainly categorized into depth map based and volumetric based methods according to the 3D representation form, and representative methods are reviewed in detail. Specifically, the plane sweep based methods leveraging depth maps are presented following the stage of approaches, i.e. feature extraction, cost volume construction, cost volume regularization, depth map regression and post-processing. This review also summarizes several widely used datasets and their corresponding metrics for evaluation. Finally, several insightful observations and challenges are put forward enlightening future research directions.     

Report on Dialogue Specification Tools

In this report we have presented some of the issues pertaining to the notations used in UIMSs. At the present time there are a small number of implemented UIMSs, so there is some experience to draw upon. This is the first workshop of this nature where there has been a significant number of participants with implementation experience. This experience seemed to raise more issues than it resolved. The conclusion that can be drawn from this is there is still a considerable amount of work to be done in notations for UIMSs.
One of the major problems encountered by this working group was the inability to compare different UIMSs. The systems discussed in this group have been used to produce user interfaces for different application areas, with different interaction styles and requirements. This makes it very difficult to compare the ease of use (for the user interface designer), and the quality of the resulting user interface. This problem would be partially solved by constructing a standard set of user interface problems. Each of the UIMSs could be used to solve these problems, and the results used as a means of comparison. This set of problems could be viewed as a benchmark test for user interface management systems. Along with developing the problems, techniques for measuring ease of use and the quality of the user interface must also be developed.     

A multicamera setup for generating stereo panoramic video

Traditional visual communication systems convey only two-dimensional (2-D) fixed field-of-view (FOV) video information. The viewer is presented with a series of flat, nonstereoscopic images, which fail to provide a realistic sense of depth. Furthermore, traditional video is restricted to only a small part of the scene, based on the director's discretion and the user is not allowed to "look around" in an environment. The objective of this work is to address both of these issues and develop new techniques for creating stereo panoramic video sequences. A stereo panoramic video sequence should be able to provide the viewer with stereo vision at any direction (complete 360-degree FOV) at video rates. In this paper, we propose a new technique for creating stereo panoramic video using a multicamera approach, thus creating a high-resolution output. We present a setup that is an extension of a previously known approach, developed for the generation of still stereo panoramas, and demonstrate that it is capable of creating high-resolution stereo panoramic video sequences. We further explore the limitations involved in a practical implementation of the setup, namely the limited number of cameras and the nonzero physical size of real cameras. The relevant tradeoffs are identified and studied.     

结合图像融合算法与人眼跟踪的立体视频

由于多视点立体视频合成具有数据量大,图像处理速度要求较高,支持的立体视角有限等特点,这些问题一直没有很好的解决并已成为多视点立体视频产业化的瓶颈。针对这种情况,提出了一种基于立体图像融合算法与人眼跟踪算法的立体视频处理系统。首先,按顺序循环读取立体视频中的每一帧,然后用立体图像融合算法对每一帧进行合成运算,接下来将融合后的图像依原有顺序进行显示与播放。同时加入人眼跟踪算法,根据观看者眼部所处的位置实时投放对应视区的图像。图像融合算法与人眼跟踪的结合有效地扩大了立体视角。实验结果表明,该方法实现了将多视点视频在立体显示器中以自由立体显示的方式展现出来,使观看者在屏幕前可以自由移动而不影响立体观看效果,同时播放速度流畅,能给观众带来比较真实的立体感受。     

Advances in computational stereo

Extraction of three-dimensional structure of a scene from stereo images is a problem that has been studied by the computer vision community for decades. Early work focused on the fundamentals of image correspondence and stereo geometry. Stereo research has matured significantly throughout the years and many advances in computational stereo continue to be made, allowing stereo to be applied to new and more demanding problems. We review recent advances in computational stereo, focusing primarily on three important topics: correspondence methods, methods for occlusion, and real-time implementations. Throughout, we present tables that summarize and draw distinctions among key ideas and approaches. Where available, we provide comparative analyses and we make suggestions for analyses yet to be done.     

An automatized method to parameterize embedded stereo matching algorithms

Many applications rely on 3D information as a depth map. Stereo Matching algorithms reconstruct a depth map from a pair of stereoscopic images. Stereo Matching algorithms are computationally intensive, that is why implementing efficient stereo matching algorithms on embedded systems is very challenging for real-time applications.Indeed, like many vision algorithms, stereo matching algorithms have to set a lot of parameters and thresholds to work efficiently. When optimizing a stereo-matching algorithm, or changing algorithms parts, all those parameters have to be set manually. Finding the most efficient solution for a stereo-matching algorithm on a specific platform then becomes troublesome.This paper proposes an automatized method to find the optimal parameters of a dense stereo matching algorithm by learning from ground truth on a database in order to compare it with respect to any other alternative.Finally, for the C6678 platform, a map of the best compromise between quality and execution time is obtained, with execution times that are between 42 ms and 382 ms and output errors that are between 6% and 9.8%.