A super-resolution algorithm is proposed to solve the problem of measuring the thin thickness of oil slick using compressed sensing theory. First, a mathematical model of a single pulse underwater ultrasonic echo is established. Then, the estimation model of the transmit time of flight (TOF) of ultrasonic echo within oil slick is given based on the sparsity of echo signals. At last, the super-resolution TOF value can be obtained by solving the sparse convex optimization problem. Simulations and experiments are conducted to validate the performance of the proposed method.

A new system of measuring the thickness of thin filn or paper using 40 kHz ultrasonic wave in air is described. The thickness of samples measured is smaller by a factor of sevreal hundreds than the wavelength of sound. Experinents with polymer and metal films and paper are described to demonstrate the measurement possibilities.