TRANSMITTING INFORMATIVE COMPONENTS OF FISHER CODES FOR MOBILE VISUAL SEARCH

Existing techniques usually adopt compact descriptors such as Fisher vector for mobile visual search, since compact descriptors are memory-efficient and suitable for fast transmission. In common Fisher vector methods, in order to make the size of image representations small enough for efficient transmission, only a small number of visual words are used. However, this choice usually sacrifices the search accuracy. In this paper, a Soft-Assignment Adjusting approach is proposed to just select informative components of descriptors for query. With this method, we can adopt more visual words to improve accuracy, while the memory usage is still low. Furthermore, efficient bitrate scalable codes are proposed in order to accommodate the network bandwidth variation. Experiments performed on benchmark datasets show that our proposed approach outperforms the state-of-the-art methods for mobile visual search.