2. The method of claim 1 , further comprising classifying each of the plurality of frames according to respective energy levels based on predetermined criteria, wherein in the detecting of the energy changes between the plurality of frames, detection of the energy change is based on differences in the respective classified energy levels.
2. The method of claim 1 , further comprising classifying each of the plurality of frames according to respective energy levels based on predetermined criteria, wherein in the detecting of the energy changes between the plurality of frames, detection of the energy change is based on differences in the respective classified energy levels. 4. The method of claim 2 , wherein, in the classifying of the frames, frames are classified according to calculated energies of respective frames.