POWER TRANSMISSION APPARATUS, POWER RECEIVING APPARATUS, CONTROL METHODS THEREOF, AND STORAGE MEDIUM

A power transmission apparatus wirelessly transmits power to a power receiving device via a power transmission coil , measures a Q factor of the power transmission coil in the time domain, and determines presence or absence of an object (foreign object) different from the power receiving apparatus based on the Q factor measured in the time domain and a reference value of the Q factor which is based on information obtained from the power receiving apparatus .