Detection apparatus, power receiving apparatus, non-contact power transmission system and detection method

A power transmitting apparatus comprising:

• power transmitting circuitry configured to transmit electric power wirelessly to a power receiving apparatus;
• a pulse generator configured to generate pulses;
• resonant circuitry including a coil and a capacitor and configured to receive the pulses from the pulse generator;
• and
• determination circuitry configured to determine whether a foreign object is present or not near the coil,
• wherein the determination circuitry is configured
• to detect a response waveform output from the resonant circuitry in response to the pulses,
• to measure a quality factor of the coil based on the response waveform, and
• to determine whether the foreign object is present or not near the coil based on the measured quality factor and a reference quality factor.