Band strengths of the Fermi resonance polyads involving C-H stretching and bending vibrations for the CHBr3 molecule are calculated with a one-dimensional dipole function and a two-dimensional dipole surface. These are obtained by the ab initio density functional method. Both treatments reproduce the interpolyad band strengths quite well, while the two-dimensional dipole moment surface is superior to the one-dimensional one in modeling the intrapolyad band strength pattern, indicating the importance of the bending vibrations in dipole moment surface and intensities calculations. The different behavior of interpolyad band strengths of CHBr3 compared to CHCl3, with an intensity anomaly occurring in the latter case, is illustrated by "dipole-weighted" overlap integrals.