Global signatures for large-scale image recognition

A system for large-scale image recognition, comprising:

• a processor;
• a main memory device;
• a persistent storage device;
• a descriptor engine executable on the processor according to software instructions stored in one of the main memory device and the persistent storage device and configured to:
• obtain a vocabulary including a set of content indices that reference corresponding cells in a descriptor space based on an input set of descriptors;
• identify a plurality of local features of an image based on the vocabulary, the local features being represented by a plurality of local descriptors;
• and
• determine an associated visual word in the vocabulary for each one of the plurality of local descriptors;
• and
• a signature engine, coupled to the descriptor engine, executable on the processor according to software instructions stored in one of the main memory device and the persistent storage device and configured to:
• generate a plurality of global signatures for the image based on the associated visual words, wherein some of the plurality of global signatures are generated using local descriptors corresponding to different cropped versions of the image, two or more of the different cropped versions of the image being centered at a same pixel location of the image;
• and
• facilitate an image recognition search using the plurality of global signatures to search a document image dataset.

A computer program product embedded in a non-transitory computer readable medium comprising instructions executable by a computer processor for large-scale image recognition, which, when executed by a processor, cause the processor to perform one or more steps comprising:

• obtaining a vocabulary including a set of content indices that reference corresponding cells in a descriptor space based on an input set of descriptors;
• identifying a plurality of local features of an image based on the vocabulary, the local features being represented by a plurality of local descriptors;
• determining an associated visual word in the vocabulary for each one of the plurality of local descriptors;
• generating a plurality of global signatures for the image based on the associated visual words, wherein some of the plurality of global signatures are generated using local descriptors corresponding to different cropped versions of the image, two or more of the different cropped versions of the image being centered at a same pixel location of the image;
• and
• facilitating an image recognition search using the plurality of global signatures to search a document image dataset.

A system for large-scale image recognition, comprising:

• means for obtaining a vocabulary including a set of content indices that reference corresponding cells in a descriptor space based on an input set of descriptors;
• means for identifying a plurality of local features of an image based on the vocabulary, the local features being represented by a plurality of local descriptors;
• means for determining an associated visual word in the vocabulary for each one of the plurality of local descriptors;
• means for generating a plurality of global signatures for the image based on the associated visual words, wherein some of the plurality of global signatures are generated using local descriptors corresponding to different cropped versions of the image, two or more of the different cropped versions of the image being centered at a same pixel location of the image;
• and
• means for facilitating an image recognition search using the plurality of global signatures to search a document image dataset.