基于鱼眼图像的全景漫游模型

介绍了如何利用鱼眼镜头所拍摄的图像建立起在固定视点上沿空间任何方向的全景漫游模型的方法,它克服了使用普通镜头需要拍摄多幅照片,经过拼结,缝合处理后才能形成全景图的缺点,试验结果证明了该方法的有效性.     

数码相机性能探秘(一)

一、镜头性以能 1.相当135照相机镜头焦距 镜头焦距决定了拍摄视角的大小、拍摄画面透视感的强弱以及拍摄景深的大小,因而焦距是所有照相机镜头最基本的参数。数码相机除了标有镜头焦距的数值外,所有的轻便数码相机还标有相当135照相机镜头的焦距。这是因为不同数码相机所用CCD芯片(或CMOS     

让节日视频变身专业小电影

春节期间,不论用数码相机、摄像机还是手机,想必大家都拍了不少的视频片段。如何把N多的视频小段合理地组合起来,成为主题鲜明并有专业范的"小电影"呢?前期摄像的技巧一部电影是由一个个镜头组成的,那么什么是一个镜头呢?这里的一个镜头是指从按下录像按钮开始拍摄直到停止拍摄为止。拍摄时最忌拖泥带水、左右摇摆、反复推拉,这些都是初拍者的通病。切记:除了要拿稳摄像机外,能用一个镜头拍完的就不要用两个镜头!节日拍摄要注意两点,一是景物和人物之间的过渡,比如要拍摄春节时公园中的热闹场面,可以先把镜头对准树上的花灯,然后逐渐把镜头向左下移动到人群上,其间可以采     

26支长焦变焦镜头联合测试 哪款镜头更适合你

长焦镜头最简单的用法就是将距离很远的拍摄主题撑满画面。我们分别对适用于佳能、尼康和索尼卡口的各型号长焦变焦镜头的评测可以帮助您在购买的时候进行决策。有这样的一些情况,会让常见的标准变焦镜头达到自己性能的极限。例如拍摄主题距离非常远,或摄影师没有机会走近拍摄主题。在这种情况下,就需要长焦镜头出场了。这种特殊镜头的优点是可以通过超长的焦距跨越摄影师和拍摄对象之间数千米的距离。     

锐化（二）

我们曾经苛刻地追求过高素质的镜头,痴迷于某种细节和某种色调的微小优势。看了锐化前后的照片对比,从我摄影41年的经验看,锐化技术比起追求某种镜头重要得多,效果也显著得多。可以这么说,一款普通专业镜头拍摄的照片锐化后,肯定会超过最昂贵的专业镜头拍摄的不经锐化的胶片或者数码影像。     

卓越影像，源自尼克尔镜头 拍摄更加光彩夺目的肖像照片！

在那个变焦镜头稀有、都用定焦镜头进行摄影的时代，人们拍摄肖像时。通常使用85mm、105mm、135mm和180mm这4种定焦镜头。当然，每一种都有不同的用途。 85mm镜头用于摄影棚中的肖像摄影。这种镜头是中焦镜头，即使镜头离开被拍摄人物有一些距离，也能够拍摄到半身像。而且不会影响摄影棚内的照明，使用起来十分方便。[第一段]     

擦拭相机镜头有讲究

数码相机的镜头就像人的眼睛．如果镜头花了会严重影响所拍摄照片的质量。但是现在的镜头都是多层镀膜．如果经常擦拭并且方法不得当，那就可能破坏镜头上面的镀膜．影响到镜头的成象质量。所以一般镜头上面有轻微的污垢．都不建议大家清洁．如果出现较严重的污渍．可以采用下面介绍的方法来清理。     

iPhone单反镜头配件

<正>随着iPhone的日益火爆,衍生出的配件等产品更是层出不穷,最近又有一款新奇配件问世,"Photojojo"的美国公司推出的专用镜头转接器,可以将单反镜头连接在iPhone上使用,拍摄出高质量的画面。该镜头转接器主要有专用的镜头转接器和铝合金的支架构成。搭配单反镜头的iPhone可以拍摄出更远、更大的景象,目前     

表达生命的张力广角人像拍摄技巧

一说起拍摄人像,懂行的老乌经常选择或向你推荐50mm、85mm这些用来拍摄人像最经典的定焦镜头,其实各种镜头只要运用得当都可以拍出效果令人惊叹的好片,下面我们就来看看如何利用广角镜头拍摄出更有张力的人像作品来。     

适马24-70mm f/2.8 DG OS HSM Art(约8099元) 腾龙SP 24-70mm f/2.8 Di VC USD G2(约8200元) 细节决定“成败”

正腾龙和适马的新一代镜头提高了摄影发烧友的预期。但是,个别之处还有着的明显弱点,着实有点让人失望。每个镜头测试,都是测试人员搜索特定拍摄主题的时刻。如果测试人员有一个远摄镜头,那他就会特别关注体育赛事摄影或者猛禽摄影;如果使用广角镜头,那就会拍摄建筑杰作了。所以我们使用这类镜头的两个最新产品,腾龙SP     

基于单幅图片的相机完全标定

现有相机标定方法的标定过程比较繁琐,不利于标定相机的广泛使用。为此,从摄像机镜头畸变矫正着手,结合标定板信息及消失点约束,提出一种基于单张图片的相机标定方法。利用非线性迭代得到相机镜头的畸变系数,通过线性求解得出相机的内参,直接计算得到相机的外参,从而实现仅需拍摄单张标定板图片的相机完全标定。实验结果表明,该方法在标定板与视平面夹角小于45°的情况下均能成功标定,并且重投影误差小于0.3像素。     

Implementation of polarization‐multiplexed tiled projection integral imaging system

Abstract— A 40‐in. tiled projection integral imaging system has been implemented, adopting a polarization‐multiplexing technique. The system is composed of two full‐high‐definition (HD) projectors, a time‐varying polarizer, a polarization preserving screen, polarization films, a lens array, and a control unit. An elemental image set is projected using two full‐HD projectors to enhance the resolution of the system. The viewing region of the system is increased by using a polarization switching method. The polarization state of the elemental image set is changed by the time‐varying polarizer, and the elemental image set is diffused by the polarization preserving screen. The elemental image set with a preserved polarization state forms a three‐dimensional image with increased viewing angle by the integration of a lens array with polarization films. A 60‐in. tiled projection integral imaging system was also demonstrated using four full‐HD projectors.     

Using cross‐talk simulation to predict the performance of anaglyph 3‐D glasses

Abstract— The anaglyph 3‐D method is a widely used technique for presenting stereoscopic 3‐D images. Its primary advantage is that it will work on any full‐color display (LCDs, plasmas, and even prints) and only requires that the user view the anaglyph image using a pair of anaglyph 3‐D glasses with usually one lens tinted red and the other lens tinted cyan (blue plus green). A common image‐quality problem of anaglyph 3‐D images is high levels of cross‐talk — the incomplete isolation of the left and right image channels such that each eye sees a “ghost” of the opposite perspective view. An anaglyph cross‐talk simulation model has been developed which allows the amount of anaglyph cross‐talk to be estimated based on the spectral characteristics of the anaglyph glasses and the display. The model is validated using a visual cross‐talk ranking test which indicates good agreement. The model is then used to consider two scenarios for the reduction of cross‐talk in anaglyph systems and finds that a considerable reduction is likely to be achieved by using spectrally pure displays. The study also finds that the 3‐D performance of commercial anaglyph glasses can be significantly better than handmade anaglyph glasses.     

Accurate Depth Dependent Lens Distortion Models: An Application to Planar View Scenarios

In order to calibrate cameras in an accurate manner, lens distortion models have to be included in the calibration procedure. Usually, the lens distortion models used in camera calibration depend on radial functions of image pixel coordinates. Such models are well-known, simple and can be estimated using just image information. However, these models do not take into account an important physical constraint of lens distortion phenomena, namely: the amount of lens distortion induced in an image point depends on the scene point depth with respect to the camera projection plane. In this paper we propose a new accurate depth dependent lens distortion model. To validate this approach, we apply the new lens distortion model to camera calibration in planar view scenarios (that is 3D scenarios where the objects of interest lie on a plane). We present promising experimental results on planar pattern images and on sport event scenarios. Nevertheless, although we emphasize the feasibility of the method for planar view scenarios, the proposed model is valid in general and can be used in any scenario where the point depth can be estimated.     

Optical simulation for cross‐talk evaluation and improvement of autostereoscopic 3‐D displays with a projector array

Abstract— Multi‐view spatial‐multiplexed autostereoscopic 3‐D displays normally use a 2‐D image source and divide the pixels to generate perspective images. Due to the reduction in the resolution of each perspective image for a large view number, a super‐high‐resolution 2‐D image source is required to achieve 3‐D image quality close to the standard of natural vision. This paper proposes an approach by tiling multiple projection images with a low magnification ratio from a microdisplay to resolve the resolution issue. Placing a lenticular array in front of the tiled projection image can lead to an autostereoscopic display. Image distortion and cross‐talk issues resulting from the projection lens and pixel structure of the microdisplay have been addressed with proper selection of the active pixel and adequate pixel grouping and masking. Optical simulation has shown that a 37‐in. 12‐view autostereoscopic display with a full‐HD (1920 × 1080) resolution can be achieved with the proposed 3‐D architecture.     

自适应柱状全景图拼接

为了实现高效高精度的全景图拼接,提出了一种面向柱状全景图的自适应拼接方法。该方法首先使用基于灰度边缘特征点的图像匹配来获得匹配坐标,并由匹配坐标唯一性计算焦距;然后在该焦距参数估计的基础上,采用新的自适应混合图像灰度匹配方法生成初期拼接图像,并根据其宽度以及相关判别条件进行焦距估计的调整,再重复迭代,以获得准确的焦距参数;最后利用基于角度1维投影的图像匹配方法进行匹配坐标的小范围校正,以及使用线性平滑算法生成最终柱状全景图。该法在精确焦距的基础上,结合了多种图像匹配算法,并根据自相关指数自适应选取结果,实现了水平和垂直两方向上的匹配定位和错位检测。实验证明,该方法不仅在真实图像上的可行,且具有较高的实时性、精度和鲁棒性。     

基于PC和OpenGL的全景图象360度漫游技术

讨论了利用OpenGL图形软件开发系统在PC机上实现全景图象360度漫游。,探讨了采用基于像素匹配的方法进行图象拼接来生成全景图象,并在此基础上利用OpenGL的纹理映射的技术,将全景图象的一部分作为纹理图象映射到由OpenGL预先构造出的虚拟视点空间上,通过改变纹理图象在PC机上实现虚拟场景的360度任意漫游。     

一种基于斜率的摄像机畸变校正方法

普通 CCD摄像机在成像时都存在畸变成像误差 ,在机器人视觉检测及自动装配中 ,有效地进行误差校正对准确确定物体的位置具有重要的意义 .本文采用带有一阶径向畸变的小孔摄像机模型 ,提出一种基于线段斜率的方法 ,对摄像机镜头的径向畸变进行校正 ,不必标定太多的摄像机的外参数 ,方法简洁 ,适合于视觉系统中对摄像机畸变的实时校正 ,或对摄像机捕获的图像进行几何校正 .实验表明 ,具有很强的鲁棒性和较高的校正精度     

Multiple elemental image mapping for resolution‐enhanced orthographic view image generation based on integral imaging

In this paper, we propose an orthographic view image generation method based on integral imaging called multiple elemental image mapping. The proposed method is based on matching regions in multiple elemental images, which are generated with different micro‐lens from the same area of a 3D object. By mapping all the matching regions to the corresponding orthographic view plane, we can enhance the resolution of the generated orthographic view image. Simulation experiments are carried out, and the results show the resolution of orthographic view image is improved obviously.     

True multi-image alignment and its application to mosaicing andlens distortion correction

Multiple images of a scene are related through 2D/3D view transformations and linear and nonlinear camera transformations. We present an algorithm for true multi-image alignment that does not rely on the measurements of a reference image being distortion free. The algorithm is developed to specifically align and mosaic images using parametric transformations in the presence of lens distortion. When lens distortion is present, none of the images can be assumed to be ideal. In our formulation, all the images are modeled as intensity measurements represented in their respective coordinate systems, each of which is related to an ideal coordinate system through an interior camera transformation and an exterior view transformation. The goal of the accompanying algorithm is to compute an image in the ideal coordinate system while solving for the transformations that relate the ideal system with each of the data images. Key advantages of the technique presented in this paper are: (i) no reliance on one distortion free image, (ii) ability to register images and compute coordinate transformations even when the multiple images are of an extended scene with no overlap between the first and last frame of the sequence, and (iii) ability to handle linear and nonlinear transformations within the same framework. Results of applying the algorithm are presented for the correction of lens distortion, and creation of video mosaics