performance gain of the four proposed models, the retrieval precisions of GMSH, BMSH, GMSH-S and BMSH-S using 32-bit hashing codes on the three datasets are plotted together in Figure 4.
for BMSH, the difference between the best and worst precisions on the three datasets are 0.0123, 0.0052 and 0.0134, respectively, which are small comparing to the gains that BMSH has achieved.