CBIR	Content Based Image Retrieval
BOVW	Bag of Visual Words
SIFT	Scale Invariant Feature Transform
CNN	Convolutional Neural Network
DNN	Deep Neural Network
TL	Transfer Learning
RDE	Recursive Density Estimation
SPM	Spatial Pyramid Matching
LLC	Local Linear Constraint
FV	Fisher Vector
VLAD	Vector of Locally Aggregated Descriptors
MFF	Multiple Feature Fusion
IR	Information Retrieval
RL	Representation Learning