Image retrieval using discriminative visual features

A method of searching for images in a corpus of searchable images based on a query image, the method comprising:

• detecting, by a computing device, a plurality of visual features for the query image;
• computing, by the computing device, a plurality of descriptors based on the plurality of visual features;
• computing, by the computing device, a visual word corresponding to each of the plurality of descriptors by quantizing each descriptor using a collection of known visual words;
• computing, by the computing device, a weight for each descriptor among the plurality of descriptors to produce a plurality of weighted descriptors, wherein computing a weight for a descriptor comprises calculating the weight based on a vector associated with the visual word corresponding to the descriptor and a concatenated vector of a local context and a global context and based on a difference between the vector associated with the visual word corresponding to the descriptor and vectors associated with visual words corresponding to one or more descriptors of the plurality of descriptors that are neighbors of the descriptor;
• utilizing the plurality of descriptors to retrieve a plurality of candidate images from the corpus of searchable images based on the query image, by the computing device, wherein the images of the corpus of searchable images are indexed by the weighted descriptors;
• ranking the plurality of candidate images using spatial verification;
• and
• sorting and presenting the ranked plurality of candidate images based on a strength of the match between each candidate image and the query image by the computing device.

An image search system comprising a computing device, the computing device comprising:

• a feature detection component for detecting at least one visual feature in an image;
• a feature description component for abstracting from the at least one visual feature a plurality of vectors pertaining to at least one vector abstraction from among the following vector abstractions:
• intensity, rotation, and scale;
• a visual word conversion component for quantizing the at least one resulting vector into at least one visual word using a collection of known visual words;
• a weighting engine for weighting the at least one visual word by calculating a weight based on a vector associated with the visual word and a concatenated vector of a local context and a global context and based on a difference between the vector associated with the visual word and vectors associated with visual words that are neighbors of the at least one visual word;
• and
• an image store for storing the image, wherein a plurality of images in the image store are indexed based on the weighted visual words.