基于立体全景漫游中深度图获取技术的研究

近年来,随着硬件技术的进步和计算机视觉理论的发展,为了增强用户的沉浸感和体验,立体全景技术被广泛应用于生产和生活中。针对多视点立体全景三维重建中深度图的获取问题,提出了一种新的深度图生成方法。首先将前后摄像机拍摄的图像进行配准,然后通过线性变换矩阵得到对应像素点与中心像素的距离,最后利用提出的算法求得深度图。     

基于视差重映射的立体图像视觉舒适度提升

目的 针对人眼观看立体图像内容可能存在的视觉不舒适性,基于视差对立体图像视觉舒适度的影响,提出了一种结合全局线性和局部非线性视差重映射的立体图像视觉舒适度提升方法。方法 首先,考虑双目融合限制和视觉注意机制,分别结合空间频率和立体显著性因素提取立体图像的全局和局部视差统计特征,并利用支持向量回归构建客观的视觉舒适度预测模型作为控制视差重映射程度的约束;然后,通过构建的预测模型对输入的立体图像的视觉舒适性进行分析,就欠舒适的立体图像设计了一个两阶段的视差重映射策略,分别是视差范围的全局线性重映射和针对提取的潜在欠舒适区域内视差的局部非线性重映射;最后,根据重映射后的视差图绘制得到舒适度提升后的立体图像。结果 在IVY Lab立体图像舒适度测试库上的实验结果表明,相较于相关有代表性的视觉舒适度提升方法对于欠舒适立体图像的处理结果,所提出方法在保持整体场景立体感的同时,能更有效地提升立体图像的视觉舒适度。结论 所提出方法能够根据由不同的立体图像特征构建的视觉舒适度预测模型来自动实施全局线性和局部非线性视差重映射过程,达到既改善立体图像视觉舒适度、又尽量减少视差改变所导致的立体感削弱的目的,从而提升立体图像的整体3维体验。     

Visual comfort prediction for stereoscopic image using stereoscopic visual saliency

Perceptually salient regions of stereoscopic images significantly affect visual comfort (VC). In this paper, we propose a new objective approach for predicting VC of stereoscopic images according to visual saliency. The proposed approach includes two stages. The first stage involves the extraction of foreground saliency and depth contrast from a disparity map to generate a depth saliency map, which in turn is combined with 2D saliency to obtain a stereoscopic visual saliency map. The second stage involves the extraction of saliency-weighted VC features, and feeding them into a prediction metric to produce VC scores of the stereoscopic images. We demonstrate the effectiveness of the proposed approach compared with the conventional prediction methods on the IVY Lab database, with performance gain ranging from 0.016 to 0.198 in terms of correlation coefficients.     

Content-aware disparity adjustment for different stereo displays

In this paper, we present an effective disparity mapping method for binocular stereoscopic image. It is inspired by the observation that its displayed depth would change, when a stereoscopic image is displayed on different size screens. The phenomenon may bring an uncomfortable experience for viewers. To make a comfortable stereoscopic image for viewers, moreover to adapt a stereoscopic image to a target display screen, we propose a content-aware disparity adjustment method. Firstly, the disparity mapping is established to control and retarget the depth of a stereoscopic scene. Then, the relationship between the disparity editing and image content editing is established to guide the proposed warping model. At last, to implement the disparity mapping operator, we propose a content-aware stereoscopic mesh warping model, which can simultaneously avoid the salient region distortion and adjust disparity to a target range by establishing the relationship. Experimental results show that the proposed method can effectively adjust disparity of stereoscopic image, which not only avoids the salient region distortion and adjusts disparity to a target range.     

自动巡线小车的图像采集系统开发与优化

为了实现自动巡线小车的路径精确识别,同时不牺牲系统的运行速度,开发了一种由CMOS数字摄像头OV6620和飞思卡尔MC9S12XS128微控制器组成的图像采集系统.采用双口静态存储器IDT7008作为数据缓存实现系统的优化,引入分割最佳阀值的迭代算法和中值滤波快速算法,提高了图像边缘检测的抗干扰能力和边缘定位的精确性,增强了图像的平滑性,边缘定位精确度可达80%以上.实验结果表明,该图像采集系统简单可靠,性价比高,便于调试,大大减少了图像采集和处理的时间,应用在自动巡线小车上取得了良好效果.     

用于岩心扫描的彩色线阵CCD图像采集系统

针对岩心资源数字化的需求,设计并实现了一种用于岩心图像扫描仪的彩色线阵CCD图像采集系统。实际应用表明，该系统能很好地解决现有系统的分辨率低、成本高的问题。可为后继的岩心图像分析工作提供可靠的依据。     

An automatic adjustment procedure for rational splines

This paper presents the development of an adjustment method for the rational spline. The adjustment of the spline is completed by tensioning each internal section until the spline conforms to user defined data in a way which is both accurate and esthetically pleasing. The tensioning rationale for the rational spline is developed for use in an interactive mode with minicomputer and graphics terminal, but may also be used in a batch environment.     

立体视频编码中运动和视差联合估计算法的研究

立体视频编码不仅要在同一个视点间进行运动估计,还要在相邻视点间进行视差估计,计算复杂度非常高.如何有效地结合运动估计和视差估计,降低运算复杂度是当前亟待解决的问题.本文详细分析了立体视频左右通道视频流之间的相关性,提出一种运动和视差联合估计快速算法.根据运动—视差模型,结合时空域的多参考帧来进行联合的运动和视差估计,实现对数据的有效编码压缩.实验证明,该算法与传统的全搜索算法相比,能在保证率失真性能基本不变的前提下,降低96.45%的运算复杂度,大大提高编码速度.     

Methods for automatic and assisted image annotation

Personal memories composed of digital pictures are very popular at the moment. To retrieve these media items annotation is required. During the last years, several approaches have been proposed in order to overcome the image annotation problem. This paper presents our proposals to address this problem. Automatic and semi-automatic learning methods for semantic concepts are presented. The automatic method is based on semantic concepts estimated using visual content, context metadata and audio information. The semi-automatic method is based on results provided by a computer game. The paper describes our proposals and presents their evaluations.     

Neural ranking for automatic image annotation

Automatic image annotation aims to predict labels for images according to their semantic contents and has become a research focus in computer vision, as it helps people to edit, retrieve and understand large image collections. In the last decades, researchers have proposed many approaches to solve this task and achieved remarkable performance on several standard image datasets. In this paper, we propose a novel learning to rank approach to address image auto-annotation problem. Unlike typical learning to rank algorithms for image auto-annotation which directly rank annotations for image, our approach consists of two phases. In the first phase, neural ranking models are trained to rank image’s semantic neighbors. Then nearest-neighbor based models propagate annotations from these semantic neighbors to the image. Thus our approach integrates learning to rank algorithms and nearest-neighbor based models, including TagProp and 2PKNN, and inherits their advantages. Experimental results show that our method achieves better or comparable performance compared with the state-of-the-art methods on four challenging benchmarks including Corel5K, ESP Games, IAPR TC-12 and NUS-WIDE.

     

一种新的自动图像配准技术*

提出了一种自动图像配准方法.该方法首先使用模板匹配获得图像间的粗匹配点,然后利用这些粗匹配点估计图像之间的变换参数,并通过统计这些变换参数的适用情况,选取出一组最佳的图像变换参数,从而实现了图像间的自动配准.实验验证,该方法在两幅图像间存在平移、转动且重叠区域较少时,仍能准确得匹配这两幅图像.     

Fingerprint image analysis for automatic identification

Most of the papers on fingerprints deal with classification of fingerprint images. Fingerprint databases being large (in the range of millions), the effort in matching of fingerprints within a class or when the class is unknown, is very significant. This requires fingerprint image analysis and extraction of the “minutiae” features, which are used for matching FPs. In this paper a scheme of preprocessing and feature extraction of fingerprint images for automatic identification is presented, which works even if the pattern class is unknown. The identification of fingerprints is based on matching the minutiae features of a given finger-print against those stored in the database. The core and delta information is used for classification and for registration while matching. These algorithms have been tested for more than 10,000 fingerprint images of different qualities. The results are manually verified and found to be very good for practical application. A few sample results are presented.     

An automatic procedure for image segmentation

A procedure for image segmentation involving no image-dependent thresholds is described. The method involves not only detection of edges but also production of closed region boundaries. The method has been developed and tested on head and shoulder images.     

Effect of disparity and viewing ambient illumination on stereoscopic viewing: An eye movement approach

Researchers have found that factors related to viewing content and viewing environment could influence viewers' stereoscopic viewing experiences. In this paper, the effect of both disparity and viewing ambient illumination condition on stereoscopic viewing was investigated by using an eye movement approach. The eye movement responses to random dot stereograms (RDS) stimuli in stereoscopic viewing were studied by performing a fusion range measurement experiment involving a judgment task. The fusion ranges under two ambient illumination conditions, eye movement responses to RDS stimuli and effects of disparity on eye movement parameters, were analyzed, respectively. The experimental results showed that fusion range under two ambient illumination conditions were different, and changes of eye movement parameters were different among various disparities when ambient illumination conditions varied. As a result, in order to improve viewers' viewing experiences when viewing different 3D contents, the arrangement of viewing ambient illumination conditions and the selection of disparity should be appropriately considered. The findings in this paper provide guidelines to reasonably arrange the viewing ambient illumination condition and efficiently produce healthy disparity in stereoscopic viewing.     

A Java program for stereo retinal image visualization

Stereo imaging of the optic-disc is a gold standard examination of glaucoma, and progression of glaucoma can be detected from temporal stereo images. A Java-based software system is reported here which automatically aligns the left and right stereo retinal images and presents the aligned images side by side, along with the anaglyph computed from the aligned images. Moreover, the disparity between two aligned images is computed and used as the depth cue to render the optic-disc images, which can be interactively edited, panned, zoomed, rotated, and animated, allowing one to examine the surface of the optic-nerve head from different view angles. Measurement including length, area, and volume of regions of interest can also be performed interactively.     

Deformed cross-dissolves for image interpolation in scientific visualization

Deformed cross-dissolves are methods for inconspicuous interpolation between images. We describe methods for deformation based on scattered data interpolation methods using correspondence points in the images to be interpolated and an algorithm for automatic establishment of these correspondence points. We also describe efficient cross-dissolve algorithms for the computation of intermediate images. Results for interpolation in the field of medical visualization are presented.