Problems with current CBIR systems

Semantic gap – Low-level image features (e.g., a pattern of red and green pixels in a matrix of a certain size) are not translated into high-level semantic concepts (e.g., a Christmas tree) in the minds of users, so formulation of queries is more troublesome than in text-based IR systems
Nature of search session – “The underlying search need is dynamic and evolving in the course of a search session.”

Semantic gap – Low-level image features (e.g., a pattern of red and green pixels in a matrix of a certain size) are not translated into high-level semantic concepts (e.g., a Christmas tree) in the minds of users, so formulation of queries is more troublesome than in text-based IR systems