MiPai: using the PP-Index to build an efficient and scalable similarity search system

MiPai is an image search system that provides visual similarity search and text-based search functionalities. The similarity search functionality is implemented by means of the Permutation Prefix Index (PP-Index), a novel data structure for approximate similarity search. The text-based search functionality is based on a traditional inverted list index data structure. MiPai also provides a combined visual similarity/text search function.