Using Text Search Ideas to Speed Up Image Search
Microsoft Research news: Text-Search Tricks Speak Volumes in Image Search, May 2007
Finding similar images on Web used to require prohibitively high computational cost. Now however, researchers use text-search ideas to make content-based image search commercially feasible. For each image, a set of features are detected, and each feature is represented by a vector describing its characteristics such as orientation and intensity. In this way, each image resembles a document in text-search, and each vector resembles a token. Vocabulary is generated from millions of tokens gathered, and an inverted index could be built. Thus, the speed of finding a similar image on the Web falls to around 0.1 seconds.
A project call “Photo2search in Beijing” has turns this idea into reality. Geo-tagged street view images with longitude and latitude are crawled from photo-sharing websites like Flickr and put into an inverted index. Imagine you get lost in Beijing. Just pull out your camera phone, shoot a photo of your surroundings, send it to the system, and you get a digital map with your position marked on it by matching your photo to the most similar geo-tagged street view images.
Relevant lecture:
23. VECTOR MODELS (11/17)
27. MULTIMEDIA IR (12/1)