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例:K-means Hashing提供的代碼optimize_one_iter函數(shù)內(nèi)部用到fminunc,代價(jià)函數(shù)是eval_one_center函數(shù),看eval_one_center函數(shù)的注釋是this function computes the cost of Eqn. (8) given a center c_j
摘要: http://xilinx.eetrend.com/article/8919
一、特征提取Feature Extraction:
SIFT [1] [Demo program][SIFT Library] [VLFeat]PCA-SIFT [2] [Project]Affine-SIFT [3] [Project]SURF [4] [OpenSURF] [Matlab Wrapper]Affi... 閱讀全文
http://www.valseonline.org/thread-505-1-1.html
【2015】
[1]. E.Sariyanidi, H. Gunes, A. Cavallaro, Automatic Analysisof Facial Affect: A Survey of Registration, Representation, and Recognition,IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE, VOL. 37, NO. 6,JUNE 2015
[2]. T. Li,H. Chang, M. Wang, B.B. Ni, R.C. Hong, S.C. Yan, CrowdedScene Analysis: A Survey, IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FORVIDEO TECHNOLOGY, VOL. 25, NO. 3, MARCH 2015
[3]. Z.Zhang, Y. Xu, J. Yang, X.L. Li, D. Zhang, A Survey ofSparse Representation: Algorithms and Applications, IEEE ACCESS, date ofpublication May 6, 2015
[4]. J.Galbally, S. Marcel, J. Fierrez, Biometric AntispoofingMethods: A Survey in Face Recognition, IEEE ACCESS, date of publicationDecember 18, 2014
[5]. B.Tian, B. T. Morris, M. Tang, Y.Q. Liu, Y. J. Yao, C. Guo, D.Y. Shen, S.H. Tang, Hierarchical and Networked Vehicle Surveillance in ITS:A Survey, IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS, VOL.16, NO. 2, APRIL 2015
[6]. A. Betancourt,P. Morerio, C. S. Regazzoni, and M. Rauterberg, TheEvolution of First Person Vision Methods: A Survey, IEEE TRANSACTIONS ONCIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY, VOL. 25, NO. 5, MAY 2015
[7]. L.Shao, F. Zhu, and X.L. Li, Transfer Learning for VisualCategorization: A Survey, IEEE TRANSACTIONS ON NEURAL NETWORKS ANDLEARNING SYSTEMS, VOL. 26, NO. 5, MAY 2015
【2014】
[8]. S. Fu,H. B. He, Z.G. Hou, Learning Race from Face: A Survey, IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE, VOL. 36, NO.12, DECEMBER 2014
[9]. H.L. Zhou,A. Mian, L. Wei, D. Creighton, M. Hossny, and S. Nahavandi, Recent Advances on Singlemodal and Multimodal FaceRecognition: A Survey, IEEE TRANSACTIONS ON HUMAN-MACHINE SYSTEMS, VOL.44, NO. 6, DECEMBER 2014
【2013】
[10]. O. D. Lara, M.A. Labrador, A Survey on Human Activity Recognition using WearableSensors, IEEE COMMUNICATIONS SURVEYS & TUTORIALS, VOL. 15, NO. 3,THIRD QUARTER 2013
[11]. A. Sotiras, C. Davatzikos, Nikos. Paragios, Deformable Medical Image Registration: A Survey, IEEETRANSACTIONS ON MEDICAL IMAGING, VOL. 32, NO. 7, JULY 2013
[12]. A. Alrahayfeh, M. Faezipour, Eye Tracking and Head Movement Detection: A State-of-ArtSurvey, IEEE Journal of Translational Engineering in Health andMedicine, 2013
[13]. P.V.K. Borges, N. Conci, and A. Cavallaro, Video-Based Human Behavior Understanding: A Survey, IEEETRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY, VOL. 23, NO. 11,NOVEMBER 2013
降維(比如PCA或者random projection) -> KDE(kernel density estimation)來(lái)估算密度 -> KL divergence
% 將訓(xùn)練數(shù)據(jù)和測(cè)試數(shù)據(jù)都去中心化X = traindata; label = traingnd; m = mean(X); X_zm = bsxfun(@minus, X, m); traindata_zm = bsxfun(@minus, traindata, m); testdata_zm = bsxfun(@minus, testdata, m); matlab函數(shù) bsxfun淺談(轉(zhuǎn)載) http://blog.sina.com.cn/s/blog_9e67285801010ttn.html
網(wǎng)上關(guān)于bsxfun的東西不多,今天需要看到一個(gè),由于原博文插入的圖片顯示不出來(lái),于是筆者大發(fā)善心進(jìn)行了contrl+V 以及alt+ctrl+A的操作,供大家交流學(xué)習(xí)。
bsxfun是一個(gè)matlab自版本R2007a來(lái)就提供的一個(gè)函數(shù),作用是”applies an element-by-element binary operation to arrays a and b, with singleton expansion enabled.”
舉個(gè)例子。假設(shè)我們有一列向量和一行向量。
a = randn(3,1), b = randn(1,3) a = -0.2453 -0.2766 -0.1913 b = 0.6062 0.5655 0.9057
我們可以很簡(jiǎn)單的使用matlab的外乘c=a*b來(lái)得到,如圖 bsxfun淺談(轉(zhuǎn)載)" o:button="t" target='"_blank"' o:spid="_x0000_i1025">bsxfun淺談(轉(zhuǎn)載)" src="file:///C:\Users\jie\AppData\Local\Temp\msohtmlclip1\01\clip_image001.jpg"> 但如果我們想用”外加”呢?也就是說(shuō)把上式求解過(guò)程中的乘號(hào)換做加號(hào)?
這時(shí)我們可以用c=bsxfun(@plus,a,b)來(lái)實(shí)現(xiàn)。
bsxfun的執(zhí)行是這樣的,如果a和b的大小相同,那么c=a+b. 但如果有某維不同,且a或b必須有一個(gè)在這一維的維數(shù)為1, 那么bsxfun就將少的這個(gè)虛擬的復(fù)制一些來(lái)使與多的維數(shù)一樣。在我們這里,b的第一維只有1(只一行),所以bsxfun將b復(fù)制3次形成一個(gè)3×3的矩陣,同樣也將a復(fù)制成3×3的矩陣。這個(gè)等價(jià)于c=repmat(a,1,3)+repmat(b,3,1)。這里
repmat(a,1,3) ans = -0.2453 -0.2453 -0.2453 -0.2766 -0.2766 -0.2766 -0.1913 -0.1913 -0.1913
repmat是顯式的復(fù)制,當(dāng)然帶來(lái)內(nèi)存的消耗。而bsxfun是虛擬的復(fù)制,實(shí)際上通過(guò)for來(lái)實(shí)現(xiàn),等效于for(i=1:3),for(j=1:3),c(i,j)=a(i)+b(j);end,end。但bsxfun不會(huì)有使用matlab的for所帶來(lái)額外時(shí)間。實(shí)際驗(yàn)證下這三種方式
>> c = bsxfun(@plus,a,b) c = 0.3609 0.3202 0.6604 0.3296 0.2889 0.6291 0.4149 0.3742 0.7144 >> c = repmat(a,1,3)+repmat(b,3,1) c = 0.3609 0.3202 0.6604 0.3296 0.2889 0.6291 0.4149 0.3742 0.7144 >> for(i=1:3),for(j=1:3),c(i,j)=a(i)+b(j);end,end,c c = 0.3609 0.3202 0.6604 0.3296 0.2889 0.6291 0.4149 0.3742 0.7144
從計(jì)算時(shí)間上來(lái)說(shuō)前兩種實(shí)現(xiàn)差不多,遠(yuǎn)高于for的實(shí)現(xiàn)。但如果數(shù)據(jù)很大,第二種實(shí)現(xiàn)可能會(huì)有內(nèi)存上的問(wèn)題。所以bsxfun最好。
下面看一個(gè)更為實(shí)際的情況。假設(shè)我們有數(shù)據(jù)A和B, 每行是一個(gè)樣本,每列是一個(gè)特征。我們要計(jì)算高斯核,既:
這里@plus是加法的函數(shù)數(shù)柄,相應(yīng)的有減法@minus, 乘法@times, 左右除等,具體可見(jiàn) doc bsxfun.
k(||x-xc||)=exp{- ||x-xc||^2/(2*σ)^2) } 其中xc為核函數(shù)中心,σ為函數(shù)的寬度參數(shù) , 控制了函數(shù)的徑向作用范圍。
當(dāng)然可以用雙重for實(shí)現(xiàn)(如果第一直覺(jué)是用三重for的話…)。
K1 = zeros(size(A,1),size(B,1)); for i = 1 : size(A,1) for j = 1 : size(B,1) K1(i,j) = exp(-sum((A(i,:)-B(j,:)).^2)/beta); end end
使用2,000×1,000大小的A和B, 運(yùn)行時(shí)間為88秒。 考慮下面向量化后的版本:
sA = (sum(A.^2, 2)); sB = (sum(B.^2, 2)); K2 = exp(bsxfun(@minus,bsxfun(@minus,2*A*B', sA), sB')/beta);
使用同樣數(shù)據(jù),運(yùn)行時(shí)間僅0.85秒,加速超過(guò)100倍。 如要判斷兩者結(jié)果是不是一樣,可以如下
assert(all(all(abs(K1-K2)<1e-12)))
谷歌上直接搜索文件名,找到citeseer的鏈接,里面直接有BibTex; 或者 谷歌上直接搜索文件名 BibTex 搜索:DBLP,文獻(xiàn)名。有時(shí)比如不知道ICML的頁(yè)碼,通過(guò)這種方式也許能找到
在Endnote中,選擇輸出樣式,就是可以選擇IEEE的地方選擇BibTex Export,右鍵選中參考文獻(xiàn),選擇Copy Formatted,拷貝到latex中即可
問(wèn)題:兩個(gè)圖像矩陣A=M*N*K1,B=M*N*K2,第三維K1,K2表示數(shù)量,matlab怎么快速實(shí)現(xiàn)他們?cè)诘谌S數(shù)量上的疊加。 答:cat(3,A,B)
20150717,筆記本電腦x240s,剛開(kāi)始以為是電腦保護(hù)色的問(wèn)題,將保護(hù)色去掉不行。將整個(gè)office重裝還是不行??粗匮b后,美化大師還在,抱著試試看的態(tài)度,卸載美化大師就可以了
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