learning to hash with its application to big data ... · with its application to big data retrieval...
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Learning to Hashwith its Application to Big Data Retrieval and Mining
o�
Department of Computer Science and EngineeringShanghai Jiao Tong University
Shanghai, China
Joint work with ��h, ÜÀ�, L¯¿
Dec 21, 2013
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 1 / 49
Outline
1 IntroductionProblem DefinitionExisting Methods
2 Isotropic HashingModelLearningExperiment
3 Multiple-Bit QuantizationDouble-Bit QuantizationManhattan Quantization
4 Conclusion
5 Reference
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 2 / 49
Introduction
Outline
1 IntroductionProblem DefinitionExisting Methods
2 Isotropic HashingModelLearningExperiment
3 Multiple-Bit QuantizationDouble-Bit QuantizationManhattan Quantization
4 Conclusion
5 Reference
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 3 / 49
Introduction Problem Definition
Nearest Neighbor Search (Retrieval)
Given a query point q, return the points closest (similar) to q in thedatabase(e.g. images).
Underlying many machine learning, data mining, information retrievalproblems
Challenge in Big Data Applications:
Curse of dimensionality
Storage cost
Query speedLi (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 4 / 49
Introduction Problem Definition
Similarity Preserving Hashing
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 5 / 49
Introduction Problem Definition
Reduce Dimensionality and Storage Cost
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 6 / 49
Introduction Problem Definition
Querying
Hamming distance:
||01101110, 00101101||H = 3||11011, 01011||H = 1
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 7 / 49
Introduction Problem Definition
Querying
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 8 / 49
Introduction Problem Definition
Querying
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 9 / 49
Introduction Problem Definition
Fast Query Speed
By using hashing scheme, we can achieve constant or sub-linearsearch time complexity.
Exhaustive search is also acceptable because the distance calculationcost is cheap now.
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 10 / 49
Introduction Problem Definition
Two Stages of Hash Function Learning
Projection Stage (Dimension Reduction)
Projected with real-valued projection functionGiven a point x, each projected dimension i will be associated with areal-valued projection function fi(x) (e.g. fi(x) = wT
i x)
Quantization Stage
Turn real into binary
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 11 / 49
Introduction Existing Methods
Data-Independent Methods
The hashing function family is defined independently of the trainingdataset:
Locality-sensitive hashing (LSH): (Gionis et al., 1999; Andoni andIndyk, 2008) and its extensions (Datar et al., 2004; Kulis andGrauman, 2009; Kulis et al., 2009).
SIKH: Shift invariant kernel hashing (SIKH) (Raginsky and Lazebnik,2009).
Hashing function: random projections.
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 12 / 49
Introduction Existing Methods
Data-Dependent Methods
Hashing functions are learned from a given training dataset.
Relatively short codes
Seminal papers: (Salakhutdinov and Hinton, 2007, 2009; Torralba et al.,2008; Weiss et al., 2008)
Two categories:
Unimodal
Supervised methodsgiven the labels yi or triplet (xi, xj , xk)Unsupervised methods
Multimodal
Supervised methodsUnsupervised methods
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 13 / 49
Introduction Existing Methods
(Unimodal) Unsupervised Methods
No labels to denote the categories of the training points.
PCAH: principal component analysis.
SH: (Weiss et al., 2008) eigenfunctions computed from the datasimilarity graph.
ITQ: (Gong and Lazebnik, 2011) orthogonal rotation matrix torefine the initial projection matrix learned by PCA.
AGH: Graph-based hashing (Liu et al., 2011).
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 14 / 49
Introduction Existing Methods
(Unimodal) Supervised (semi-supervised) Methods
Class labels or pairwise constraints:
SSH: Semi-Supervised Hashing (SSH) (Wang et al., 2010a,b) exploitsboth labeled data and unlabeled data for hash function learning.
MLH: Minimal loss hashing (MLH) (Norouzi and Fleet, 2011) basedon the latent structural SVM framework.
KSH: Kernel-based supervised hashing (Liu et al., 2012)
LDAHash: Linear discriminant analysis based hashing (Strecha et al.,2012)
Triplet-based methods:
Hamming Distance Metric Learning (HDML) (Norouzi et al., 2012)
Column Generation base Hashing (CGHash) (Li et al., 2013)
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 15 / 49
Introduction Existing Methods
Multimodal Methods
Multi-Source Hashing
Cross-Modal Hashing
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Introduction Existing Methods
Multi-Source Hashing
Aims at learning better codes by leveraging auxiliary views thanunimodal hashing.
Assumes that all the views provided for a query, which are typicallynot feasible for many multimedia applications.
Multiple Feature Hashing (Song et al., 2011)
Composite Hashing (Zhang et al., 2011)
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 17 / 49
Introduction Existing Methods
Cross-Modal Hashing
Given a query of either image or text, return images or texts similar to it.
Cross View Hashing (CVH) (Kumar and Udupa, 2011)
Multimodal Latent Binary Embedding (MLBE) (Zhen and Yeung,2012a)
Co-Regularized Hashing (CRH) (Zhen and Yeung, 2012b)
Inter-Media Hashing (IMH) (Song et al., 2013)
Relation-aware Heterogeneous Hashing (RaHH) (Ou et al., 2013)
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 18 / 49
Introduction Existing Methods
IS�ó�
FDU: Yugang Jiang, Xuanjing Huang
HKUST: Dit-Yan Yeung
IA-CAS: Cheng-Lin Liu, Yan-Ming Zhang
ICT-CAS: Hong Chang
MSRA: Kaiming He, Jian Sun, Jingdong Wang
NUST: Fumin Shen
SYSU: Weishi Zheng
Tsinghua: Peng Cui, Shiqiang Yang, Wenwu Zhu
ZJU: Jiajun Bu, Deng Cai, Xiaofei He, Yueting Zhuang......
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 19 / 49
Isotropic Hashing
Outline
1 IntroductionProblem DefinitionExisting Methods
2 Isotropic HashingModelLearningExperiment
3 Multiple-Bit QuantizationDouble-Bit QuantizationManhattan Quantization
4 Conclusion
5 Reference
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 20 / 49
Isotropic Hashing
Motivation
Problem:All existing methods use the same number of bits for different projecteddimensions with different variances.
Possible Solutions:
Different number of bits for different dimensions(Unfortunately, have not found an effective way)
Isotropic (equal) variances for all dimensions
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 21 / 49
Isotropic Hashing
Contribution
Isotropic hashing (IsoHash):(Kong and Li, 2012b)hashing with isotropic variances for all dimensions
Multiple-bit quantization:(1) Double-bit quantization (DBQ):(Kong and Li, 2012a)Hamming distance driven
(2) Manhattan hashing (MH):(Kong et al., 2012)Manhattan distance driven
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 22 / 49
Isotropic Hashing
PCA Hash
To generate a code of m bits, PCAH performs PCA on X, and then usethe top m eigenvectors of the matrix XXT as columns of the projectionmatrix W ∈ Rd×m. Here, top m eigenvectors are those corresponding tothe m largest eigenvalues {λk}mk=1, generally arranged with thenon-increasing order λ1 ≥ λ2 ≥ · · · ≥ λm. Let λ = [λ1, λ2, · · · , λm]T .Then
Λ = W TXXTW = diag(λ)
Define hash functionh(x) = sgn(W Tx)
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 23 / 49
Isotropic Hashing
Weakness of PCA Hash
Using the same number of bits for different projected dimensions isunreasonable because larger-variance dimensions will carry moreinformation.
Solve it by making variances equal (isotropic)!
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 24 / 49
Isotropic Hashing
Weakness of PCA Hash
Using the same number of bits for different projected dimensions isunreasonable because larger-variance dimensions will carry moreinformation.
Solve it by making variances equal (isotropic)!
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 24 / 49
Isotropic Hashing Model
Idea of IsoHash
Learn an orthogonal matrix Q ∈ Rm×m which makesQTW TXXTWQ become a matrix with equal diagonal values.
Effect of Q: to make each projected dimension has the same variancewhile keeping the Euclidean distances between any two pointsunchanged.
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 25 / 49
Isotropic Hashing Model
Problem Definition
tr(QTW TXXTWQ) = tr(W TXXTW ) = tr(Λ) =
m∑i=1
λi
a = [a1, a2, · · · , am] with ai = a =
∑mi=1 λim
,
andT (z) = {T ∈ Rm×m|diag(T ) = diag(z)},
Problem
The problem of IsoHash is to find an orthogonal matrix Q makingQTW TXXTWQ ∈ T (a).
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 26 / 49
Isotropic Hashing Model
IsoHash Formulation
Because QTΛQ = QT [W TXXTW ]Q, let
M(Λ) = {QTΛQ|Q ∈ O(m)},
where O(m) is the set of all orthogonal matrices in Rm×m.
Then, the IsoHash problem is equivalent to:
||T − Z||F = 0,
where T ∈ T (a), Z ∈M(Λ), || · ||F denotes the Frobenius norm.
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 27 / 49
Isotropic Hashing Model
Existence Theorem
Lemma
[Schur-Horn Lemma (Horn, 1954)] Let c = {ci} ∈ Rm and b = {bi} ∈ Rm
be real vectors in non-increasing order respectively, i.e.,c1 ≥ c2 ≥ · · · ≥ cm, b1 ≥ b2 ≥ · · · ≥ bm. There exists a Hermitian matrixH with eigenvalues c and diagonal values b if and only if
k∑i=1
bi ≤k∑
i=1
ci, for any k = 1, 2, ...,m,
m∑i=1
bi =
m∑i=1
ci.
So we can prove :There exists a solution to the IsoHash problem. And this solution is in theintersection of T (a) and M(Λ).
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 28 / 49
Isotropic Hashing Learning
Learning Methods
Two methods: (Chu, 1995)
Lift and projection (LP)
Gradient Flow (GF)
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Isotropic Hashing Learning
Lift and projection (LP)
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Isotropic Hashing Learning
Gradient Flow
Objective function:
minQ∈O(m)
F (Q) =1
2||diag(QTΛQ)− diag(a)||2F .
The gradient ∇F at Q:
∇F (Q) = 2Λβ(Q),
where β(Q) = diag(QTΛQ)− diag(a).
The projection of ∇F (Q) onto O(m)
g(Q) = Q[QTΛQ, β(Q)]
where [A,B] = AB −BA is the Lie bracket.
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 31 / 49
Isotropic Hashing Learning
Gradient Flow
Objective function:
minQ∈O(m)
F (Q) =1
2||diag(QTΛQ)− diag(a)||2F .
The gradient ∇F at Q:
∇F (Q) = 2Λβ(Q),
where β(Q) = diag(QTΛQ)− diag(a).
The projection of ∇F (Q) onto O(m)
g(Q) = Q[QTΛQ, β(Q)]
where [A,B] = AB −BA is the Lie bracket.
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 31 / 49
Isotropic Hashing Learning
Gradient Flow
Objective function:
minQ∈O(m)
F (Q) =1
2||diag(QTΛQ)− diag(a)||2F .
The gradient ∇F at Q:
∇F (Q) = 2Λβ(Q),
where β(Q) = diag(QTΛQ)− diag(a).
The projection of ∇F (Q) onto O(m)
g(Q) = Q[QTΛQ, β(Q)]
where [A,B] = AB −BA is the Lie bracket.
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 31 / 49
Isotropic Hashing Learning
Gradient Flow
The vector field Q = −g(Q) defines a steepest descent flow on themanifold O(m) for function F (Q). Letting Z = QTΛQ andα(Z) = β(Q), we get
Z = [Z, [α(Z), Z]],
where Z is an isospectral flow that moves to reduce the objective functionF (Q).
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 32 / 49
Isotropic Hashing Experiment
Accuracy (mAP)
Method CIFAR
# bits 32 64 96 128 256
IsoHash 0.2249 0.2969 0.3256 0.3357 0.3651PCAH 0.0319 0.0274 0.0241 0.0216 0.0168
ITQ 0.2490 0.3051 0.3238 0.3319 0.3436
SH 0.0510 0.0589 0.0802 0.1121 0.1535
SIKH 0.0353 0.0902 0.1245 0.1909 0.3614
LSH 0.1052 0.1907 0.2396 0.2776 0.3432
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 33 / 49
Isotropic Hashing Experiment
Training Time
0 1 2 3 4 5 6
x 104
0
10
20
30
40
50
Number of training data
Tra
inin
g T
ime(
s)
IsoHash−GFIsoHash−LPITQSHSIKHLSHPCAH
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 34 / 49
Multiple-Bit Quantization
Outline
1 IntroductionProblem DefinitionExisting Methods
2 Isotropic HashingModelLearningExperiment
3 Multiple-Bit QuantizationDouble-Bit QuantizationManhattan Quantization
4 Conclusion
5 Reference
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 35 / 49
Multiple-Bit Quantization Double-Bit Quantization
Double Bit Quantization
1.5 1 0.5 0 0.5 1 1.50
500
1000
1500
2000
X
Sam
ple
Num
be
A BC D0 1
01 00 10 11
01 00 10
(a)
(b)
(c)
Point distribution of the real values computed by PCA on 22K LabelMedata set, and different coding results based on the distribution:
(a) single-bit quantization (SBQ);(b) hierarchical hashing (HH) (Liu et al., 2011);(c) double-bit quantization (DBQ).
The popular coding strategy SBQ which adopts zero as the thresholdis shown in Figure (a). Due to the thresholding, the intrinsicneighboring structure in the original space is destroyed.The HH strategy (Liu et al., 2011) is shown in Figure (b). If we used(A,B) to denote the Hamming distance between A and B, we canfind that d(A,D) < d(A,C) for HH, which is obviously notreasonable.With our DBQ code, d(A,D) = 2, d(A,B) = d(C,D) = 1, andd(B,C) = 0, which is obviously reasonable to preserve the similarityrelationships in the original space.
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 36 / 49
Multiple-Bit Quantization Double-Bit Quantization
Experiment I
Precision-recall curve on 22K LabelMe data set
0 0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
Recall
Pre
cisi
on
SH−SBQSH−HHSH−DBQ
0 0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
Recall
Pre
cisi
on
SH−SBQSH−HHSH−DBQ
SH 32 bits SH 64 bits
0 0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
Recall
Pre
cisi
on
SH−SBQSH−HHSH−DBQ
0 0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
Recall
Pre
cisi
on
SH−SBQSH−HHSH−DBQ
SH 128 bits SH 256 bits
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 37 / 49
Multiple-Bit Quantization Double-Bit Quantization
Experiment II
mAP on LabelMe data set
# bits 32 64SBQ HH DBQ SBQ HH DBQ
ITQ 0.2926 0.2592 0.3079 0.3413 0.3487 0.4002SH 0.0859 0.1329 0.1815 0.1071 0.1768 0.2649
PCA 0.0535 0.1009 0.1563 0.0417 0.1034 0.1822LSH 0.1657 0.105 0.12272 0.2594 0.2089 0.2577SIKH 0.0590 0.0712 0.0772 0.1132 0.1514 0.1737
# bits 128 256SBQ HH DBQ SBQ HH DBQ
ITQ 0.3675 0.4032 0.4650 0.3846 0.4251 0.4998SH 0.1730 0.2034 0.3403 0.2140 0.2468 0.3468
PCA 0.0323 0.1083 0.1748 0.0245 0.1103 0.1499LSH 0.3579 0.3311 0.4055 0.4158 0.4359 0.5154SIKH 0.2792 0.3147 0.3436 0.4759 0.5055 0.5325
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 38 / 49
Multiple-Bit Quantization Manhattan Quantization
Quantization Stage
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 39 / 49
Multiple-Bit Quantization Manhattan Quantization
Natural Binary Code(NBC)
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Multiple-Bit Quantization Manhattan Quantization
Manhattan Distance
Let x = [x1, x2, · · · , xd]T , y = [y1, y2, · · · , yd]T , the Manhattan distancebetween x and y is defined as follows:
dm(x,y) =
d∑i=1
|xi − yi|,
where |x| denotes the absolute value of x.
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 41 / 49
Multiple-Bit Quantization Manhattan Quantization
Manhattan Distance Driven Quantization
We divide each projected dimension into 2q regions and then use qbits of natural binary code to encode the index of each region.
For example, If q = 3, the indices of regions are {0, 1, 2, 3, 4, 5, 6, 7}and the natural binary codes are{000, 001, 010, 011, 100, 101, 110, 111}
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 42 / 49
Multiple-Bit Quantization Manhattan Quantization
Manhattan Distance Driven Quantization
We divide each projected dimension into 2q regions and then use qbits of natural binary code to encode the index of each region.
For example, If q = 3, the indices of regions are {0, 1, 2, 3, 4, 5, 6, 7}and the natural binary codes are{000, 001, 010, 011, 100, 101, 110, 111}
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 42 / 49
Multiple-Bit Quantization Manhattan Quantization
Manhattan Distance Driven Quantization
Manhattan quantization(MQ) with q bits is denoted as q-MQ.
For example, if q = 2,
dm(000100, 110000) = dd(00, 11) + dd(01, 00) + dd(00, 00)
= 3 + 1 + 0
= 4.
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 43 / 49
Multiple-Bit Quantization Manhattan Quantization
Experiment I
0 0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
Recall
Pre
cisi
on
SH SBQSH HQSH 2−MQ
SH 32 bits
0 0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
RecallP
reci
sion
SH SBQSH HQSH 2−MQ
SH 64 bits
0 0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
Recall
Pre
cisi
on
SH SBQSH HQSH 2−MQ
SH 128 bits
0 0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
Recall
Pre
cisi
on
SH SBQSH HQSH 2−MQ
SH 256 bits
0 0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
Recall
Pre
cisi
on
SIKH SBQSIKH HQSIKH 2−MQ
SIKH 32 bits
0 0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
Recall
Pre
cisi
on
SIKH SBQSIKH HQSIKH 2−MQ
SIKH 64 bits
0 0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
Recall
Pre
cisi
on
SIKH SBQSIKH HQSIKH 2−MQ
SIKH 128 bits
0 0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
Recall
Pre
cisi
on
SIKH SBQSIKH HQSIKH 2−MQ
SIKH 256 bits
Figure: Precision-recall curve on 22K LabelMe data set
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 44 / 49
Multiple-Bit Quantization Manhattan Quantization
Experiment II
Table: mAP on ANN SIFT1M data set. The best mAP among SBQ, HQ and2-MQ under the same setting is shown in bold face.
# bits 32 64 96SBQ HQ 2-MQ SBQ HQ 2-MQ SBQ HQ 2-MH
ITQ 0.1657 0.2500 0.2750 0.4641 0.4745 0.5087 0.5424 0.5871 0.6263SIKH 0.0394 0.0217 0.0570 0.2027 0.0822 0.2356 0.2263 0.1664 0.2768LSH 0.1163 0.0961 0.1173 0.2340 0.2815 0.3111 0.3767 0.4541 0.4599SH 0.0889 0.2482 0.2771 0.1828 0.3841 0.4576 0.2236 0.4911 0.5929
PCA 0.1087 0.2408 0.2882 0.1671 0.3956 0.4683 0.1625 0.4927 0.5641
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Conclusion
Outline
1 IntroductionProblem DefinitionExisting Methods
2 Isotropic HashingModelLearningExperiment
3 Multiple-Bit QuantizationDouble-Bit QuantizationManhattan Quantization
4 Conclusion
5 Reference
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 46 / 49
Conclusion
Conclusion
Hashing can significantly improve searching speed and reduce storagecost.
Projections with isotropic variances will be better than those withanisotropic variances. (IsoHash)
The quantization stage is at least as important as the projectionstage. (DBQ/MQ)
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 47 / 49
Conclusion
Q & A
Thanks!
Question?
Code available athttp://www.cs.sjtu.edu.cn/~liwujun
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Reference
Outline
1 IntroductionProblem DefinitionExisting Methods
2 Isotropic HashingModelLearningExperiment
3 Multiple-Bit QuantizationDouble-Bit QuantizationManhattan Quantization
4 Conclusion
5 Reference
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 49 / 49
References
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M. Chu. Constructing a Hermitian matrix from its diagonal entries andeigenvalues. SIAM Journal on Matrix Analysis and Applications, 16(1):207–217, 1995.
M. Datar, N. Immorlica, P. Indyk, and V. S. Mirrokni. Locality-sensitivehashing scheme based on p-stable distributions. In Proceedings of theACM Symposium on Computational Geometry, 2004.
A. Gionis, P. Indyk, and R. Motwani. Similarity search in high dimensionsvia hashing. In Proceedings of International Conference on Very LargeData Bases, 1999.
Y. Gong and S. Lazebnik. Iterative quantization: A procrustean approachto learning binary codes. In Proceedings of Computer Vision andPattern Recognition, 2011.
A. Horn. Doubly stochastic matrices and the diagonal of a rotation matrix.American Journal of Mathematics, 76(3):620–630, 1954.
Li (http://www.cs.sjtu.edu.cn/~liwujun) Learning to Hash CSE, SJTU 49 / 49
References
W. Kong and W.-J. Li. Double-bit quantization for hashing. InProceedings of the Twenty-Sixth AAAI Conference on ArtificialIntelligence (AAAI), 2012a.
W. Kong and W.-J. Li. Isotropic hashing. In Proceedings of the 26thAnnual Conference on Neural Information Processing Systems (NIPS),2012b.
W. Kong, W.-J. Li, and M. Guo. Manhattan hashing for large-scale imageretrieval. In The 35th International ACM SIGIR conference on researchand development in Information Retrieval (SIGIR), 2012.
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