A plurality of images are obtained in photography according to a plurality of photography methods, and photography result scores are calculated for the respective images. In taking the acoustics into account, the separate sound chambers are installed within the earphones according to the sound effect of different channel speakers. Alternatively, an amplitude of the first electrode combination is maintained at a target amplitude level while the amplitude of the second electrode combination is incrementally increased. When the switchover controller receives an indication that the primary processing module has failed, it designates one of the secondary processing modules to be the primary processing module. Then, the connecting sleeve is installed at another end of the outer post so as to form the connector.