Implementation of spatial touch system using time-of-flight camera

Recently developed timeofflight principle based depthsensing video camera technologies provide precise perpixel range data in addition to color video. Such cameras will find application in robotics and visionbased human computer interaction scenarios such as games and gesture input systems. Timeofflight principle range cameras are becoming more and more available. They promise to make the 3D reconstruction of scenes easier, avoiding the practical issues resulting from 3D imaging techniques based on triangulation or disparity estimation. A spatial touch system was presented which uses a depthsensing camera to touch spatial objects and details on its implementation, and how this technology will enable new spatial interactions was speculated.     

Implementation of spatial touch system using time-of-flight camera

Recently developed time-of-flight principle based depth-sensing video camera technologies provide precise per-pixel range data in addition to color video. Such cameras will find application in robotics and vision-based human computer interaction scenarios such as games and gesture input systems. Time-of-flight principle range cameras are becoming more and more available. They promise to make the 3D reconstruction of scenes easier, avoiding the practical issues resulting from 3D imaging techniques based on triangulation or disparity estimation. A spatial touch system was presented which uses a depth-sensing camera to touch spatial objects and details on its implementation, and how this technology will enable new spatial interactions was speculated.     

常规隐信道下可证明安全隐写术的有效构造方法

隐写术是在看起来无害媒体中隐藏信息的科学.文中为了解决在常规隐信道下可证明安全隐写术的有效构造问题,在不依赖于任何采样假设的前提下,提供了一种基于计算不可区分的安全隐写术构造.文中结果表明,隐信道采样器中影射函数的不可区分性是安全隐写系统抵抗自适应选择隐文攻击的必要条件.在此基础上,完整地证明了l(-1+5-2)—安全隐写系统能在-1伪随机函数和-2无偏采样函数下有效地被构造,其中,-1和-2是任意两个可忽略错误,l是多项式的隐文长度.更为重要的,文中的研究不依赖于密码系统的密文伪随机性假设和完美采样假设,因此,我们的结果对于安全隐写系统的构造和隐写分析都具有现实意义.     

明末平仪(Planispheric Astrolabe)在中国的传播——以《浑盖通宪图说》中的平仪为例

平仪 (Planispheric Astrolabe,即星盘 ;平仪为李之藻译语 )乃是一种基于希腊地心说的天文观测仪器。因为它拥有优美的结构、测量上的方便以及丰富的功能 ,它在西方 (阿拉伯地区和欧洲 )中世纪长期成为最常见、最重要的天文仪器之一。它的主要功能是报时、定方位、做为月历。因此在利玛窦东行之时 ,平仪也随着一起东传。虽然它的制造带有浓厚的西方色彩 ,但它的功能以及观测上的准确性很快引起了李之藻的兴趣 ,经过学习和实际运用 ,在1 6 0 7年他刻印了《浑盖通宪图说》。在中国这是第一部介绍平仪之制造法以及使用法的书。由于中西天文学系统互不相容的缘故 ,所以接受平仪就意味着不得不接受平仪背后以地心说为中心的西方天文知识。更何况平仪的制造乃是建立在地心说、地圆说、立体投影等之西方数学天文知识上。不过 ,对李之藻而言 ,接受西法并不代表立刻放弃中法 ,反而是西法的接受更有助于重新诠释中法。亦即他在西法上发现了被放弃多年的盖天说的新读法。换句话说 ,他就发现了一个可以调和似乎一直被认为互相矛盾的盖天和浑天的好法子。因为在他的读法里 ,盖天就成为支持地圆说的理论之缘故。而虽然李之藻这样的解释也许有助于减轻接受西法所带来的不必要的争论 ,但是他过分强调中西之“同”,而忽略     

Implementation of spatial touch system using time-of-flight camera

Recently developed time-of-flight principle based depth-sensing video camera technologies provide precise per-pixel range data in addition to color video. Such cameras will find application in robotics and vision-based human computer interaction scenarios such as games and gesture input systems. Time-of-flight principle range cameras are becoming more and more available. They promise to make the 3D reconstruction of scenes easier, avoiding the practical issues resulting from 3D imaging techniques based on t...