Liquid level measuring method based on acoustic resonance frequency nonlinear filtering

The invention relates to a liquid level measuring method based on acoustic resonance frequency nonlinear filtering. The existing measuring method generates certain error during system measurement due to the influences of the environment, hardware and the like, and reduces the measuring precision. The liquid level measuring method collects a group of synthetic wave sequences through a hardware system, performs resonance point extraction by using a multi-stage smooth filtering algorithm, obtains determination of whether the resonance point sequences have multiple points or defects and the like through the processing of a nonlinear filter based on confidence rule reasoning, and respectively processes the resonance point sequences by using a point deleting algorithm and a point complementing algorithm so as to obtain a group of new complete resonance point sequences. A plurality of liquid level measuring values are obtained by adopting the difference values between the adjacent points of the sequence and the liqu