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11.8 Further Discussion 241
Figure 11.12 The recall rate versus query size of SIFT, CHoG, and the proposed compression
approach.
quantization steps. We can observe that the proposed compression only causes up to
1.8% recall loss at point B1 as compared with point B. But the query size is reduced
more than 90%. The curve of CHoG in the research by Chandrasekhar et al. [255]
is drawn in Figure 11.12, too. We can observe that they have similar recall at similar
query sizes. Both of them have a largely decreasing slope on recall when query sizes
become too small. One thing that we have to mention here is, that for the proposed
compression, the