陶哲轩获得克拉福德奖

压缩感知届怪兽级人物陶哲轩(因为就看过压缩感知的工作
)获得了克拉福德奖。此同为瑞典皇家科学院颁奖的,为诺贝尔不喜欢的数学、地球科学、生物科学和天文学颁发的,因为比较穷的关系,每年只发一个领域的(今年发了俩个领域)。陶哲轩和同获得过菲尔茨奖的普林斯顿高等研究院的比利时数学家Jean Bourgain分享了这个奖。奖金,在2011年是600,000美刀,陶哲轩获得的是2012年的奖,Marr Prize貌似没奖金。
The Royal Swedish Academy of Sciences has decided to award the Crafoord Prize in Mathematics 2012 to Jean Bourgain, Institute for Advanced Study, Princeton, USA and Terence Tao, University of California, Los Angeles, USA,
“for their brilliant and groundbreaking work in harmonic analysis, partial differential equations, ergodic theory, number theory, combinatorics, functional analysis and theoretical computer science”.
Kmeans based indexing and Asymmetric Distance Computation for ANN search (Binary Local Feature): part1
受Herve Jegou的Hamming Embedding and Weak Geometric consistency for large-scale image search以及Product quantization for nearest neighbor search的启发,将Kmeans clustering、inverted files、Asymmetric Distance Computation应用到二进制形式的局部特征的最近邻检索。
主要思路:
用Kmeans做特征的粗索引。
根据统计数据对feature进行压缩。
检索时使用非对称的方式计算索引特征与查询特征之间的距离。
算法:
训练:
- 使用Kmeans对欲索引的特征进行聚类,得到K个中心。对二进制形式的feature做聚类时,类别中心更新方式为:对于每一个bit,统计所有落在该类别的特征的对应bit上的1,0频率,并取高者。
- 对于每个cluster,统计所有落在该类别的特征的每个bit位的1,0频率,取1或者0频率靠近50%的前M个bits。(越靠近50%,熵越大)
经过训练,我们得到两组数据:
- K个特征类别中心。
- 对于每个类别中心,都有一组“M个bit位置标示符”。这些标示符构成一个对原始feature进行压缩的依据。(本文以后将其称为投影向量)
CV Dazzle

之前介绍过一个反人脸检测的东西,作者Adam Harvey又将其发扬光大了,整出一个CV Dazzle。最早的版本没有考虑到审美上的因素,纯粹只是为了干掉人脸检测器(OpenCV based),这次Adam Harvey试图弄得。。好看点?
[招聘] 华为 多媒体技术实验室杭州分部
Job Function:
Researcher responsible for developing algorithms and prototype of research projects related to video and audio. The candidate will work with the multimedia technology lab in Hangzhou or Shenzhen.
Skills/Experience
Must hold a Bachelors and/or a Masters/or a PhD in Electrical Engineering/or Computer Engineering with at least 2+ years experience in design, development, and integration of multimedia algorithms.
Strong Knowledge in computational camera, computational photography, 3D display and video/audio signal processing.
Knowledge in video standards on H.264, MPEG4, VP6/VP8, or graphics domain, Open GL standards is a definite plus.
Knowledge in audio standards on AMR, AMR-WB, G.711, G.719 and OpenAL.
Knowledge in optical lens design is a plus.
Strong C, C++, and MatLab development skills is required.
Experience in initiating a research proposal and conduct the research activities, developing deliverable software with a GUI interface is desired.
Should have good analytical ability, problem solving skills and be a self-starter.
Work well within a matrix organization and able to influence and collaborate with team members all over the world.
vibe

ViBe – a powerful technique for background detection and subtraction in video sequences
Executive summary
Description
ViBe is a powerful pixel-based technique that detects the background in video sequences. Many experiments have shown that it performs better than the state-of-the-art techniques known in the scientific literature. In addition the computational load is lower than simple background techniques implemented in commercial products. ViBe is the perfect solution for both software and hardware implementations.
Code and program for Windows and Linux
- A program for Windows and Linux. Download an archive zip archive [10 MB - updated on May 19, 2011] to use ViBe on Windows (or under Wine in Linux). Details on this page.
The program allows you to: (1) save the result for your own images, (2) change the few parameters of ViBe to experiment with, and (3) reproduce our results. - Linux: link a C/C++ object file to your own code. We provide the object (compiled) code of ViBe for non-commercial applications. Under Linux, download the 32 bits zip or compressed tar file, or the 64 bits zip or compressed tar file. Details on this page.
机器学习中的算法(1)-决策树模型组合之随机森林与GBDT
转载自LeftNotEasy的博客
前言:
决策树这种算法有着很多良好的特性,比如说训练时间复杂度较低,预测的过程比较快速,模型容易展示(容易将得到的决策树做成图片展示出来)等。但是同时,单决策树又有一些不好的地方,比如说容易over-fitting,虽然有一些方法,如剪枝可以减少这种情况,但是还是不够的。
模型组合(比如说有Boosting,Bagging等)与决策树相关的算法比较多,这些算法最终的结果是生成N(可能会有几百棵以上)棵树,这样可以大大的减少单决策树带来的毛病,有点类似于三个臭皮匠等于一个诸葛亮的做法,虽然这几百棵决策树中的每一棵都很简单(相对于C4.5这种单决策树来说),但是他们组合起来确是很强大。
在最近几年的paper上,如iccv这种重量级的会议,iccv 09年的里面有不少的文章都是与Boosting与随机森林相关的。模型组合+决策树相关的算法有两种比较基本的形式 – 随机森林与GBDT((Gradient Boost Decision Tree),其他的比较新的模型组合+决策树的算法都是来自这两种算法的延伸。本文主要侧重于GBDT,对于随机森林只是大概提提,因为它相对比较简单。
在看本文之前,建议先看看机器学习与数学(3)与其中引用的论文,本文中的GBDT主要基于此,而随机森林相对比较独立。
KinectFusion的PCL实现
WillowGarage的猛士再次发力,实现了今年ISMAR上炫目的KinectFusion。
The preliminary source code is currently available in our SVN repository’s trunk in the CUDA/KinFu module. Since this code is still unreleased and under active development, we won’t be able to provide support via our forums yet; however, advanced users are free to check out the code and give it a try. Be advised that this code relies heavily on the NVidia CUDA development libraries for GPU optimizations and will require a compatible GPU for best results.
Moving forward, we continue to refine and improve the system, and we are hoping to improve upon the original algorithm in order to model larger scale environments in the near future. We are targeting a stable release date to coincide with the upcoming PCL 2.0 release next year. (Please note there is no planned release in the 1.x branch.)
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