Method and apparatus for discriminating ultrasonic echoes using wavelet function processing

摘要

A method of and apparatus for discriminating among ultrasonic echoes reflected from various objects in a tank containing liquid is disclosed. Ultrasonic signals are generated from an ultrasonic transducer into liquid contained in a tank. Ultrasonic echoes are received by the transducer from various objects in the tank including a surface of the liquid in response to the generated ultrasonic signal and are converted into electrical echo signals representative thereof. Data samples of the electrical echo signals are generated and processed by a signal processor using wavelet function processing to generate wavelet coefficients thereof in a wavelet domain. The wavelet coefficients of the echo data samples are used to discriminate the ultrasonic echoes reflected from the various objects in or part of the tank. In one embodiment, echoes reflected from the liquid surface are discriminated from echoes reflected from other objects based on the wavelet coefficients of the echo data samples of each. In another embodiment, energy of each of the ultrasonic echoes determined from the wavelet coefficients thereof is used to discriminate the ultrasonic echoes from the various reflective surfaces.