When codeword frequency meets geographical location

When codeword frequency meets geographical location in landmark search applications, is it still discriminative for the search procedure? In this paper, we give a systematic investigation about how geographical location affects the effectiveness of codeword frequency. We explain why the standard IDF in the BoW models is less effective in location related search applications. Consequently, we propose a "location discriminative codeword frequency " strategy to introduce the location context into the codeword discriminability measurement. This new codeword frequency is calculated in each geographical region, for which a spectral clustering scheme is proposed to partition the geographical map of each city into distinct regions. Extensive comparisons over the standard codeword frequency in state-of-the-art landmark search systems demonstrates our approach\´s effectiveness.