Apparatus and method for removing noise of ultrasonic system

An apparatus for removing noise of an ultrasonic system, the apparatus comprising:

• an ultrasonic sensor configured to transmit a transmission signal to a medium and receive a reception signal reflected from the medium;
• and
• a controller configured to
• calculate a correlation between the transmission signal and a signal in a frequency range recognized as a normal signal in the reception signal;
• compare an output value of the correlation detector with a threshold value;
• and
• determine whether the signal in the frequency range recognized as the normal signal is the normal signal or noise based on the comparison result.

A non-transitory computer readable medium containing program instructions executed by a controller, the computer readable medium comprising:

• program instructions that control a sensor to transmit a transmission signal to a medium and receiving a reception signal reflected from the medium;
• program instructions that remove noise beyond a frequency range recognized as a normal signal from the reception signal;
• program instructions that calculate a correlation between the transmission signal and a signal in the frequency range recognized as the normal signal in the reception signal;
• and
• program instructions that determine whether the signal in the frequency range recognized as the normal signal is the normal signal or noise based on the calculated correlation.