Thin bone sample assessment using ultrasonic transmitted signals based on wavelet processing method

The wavelet-based processing (WBP) method based on Meyer-Jaffard algorithm was implemented to simultaneously determine the thickness and velocity of thin cortical bone samples. Two groups of bovine samples were measured by one pair of immersion transducers with nominal frequency 2.25MHz. The WBP method was used to estimate the times of flight (TOF) of two pulses contained by one transmitted signal. The mean relative error of thickness measurement is 6.13%. The mean velocities and their standard deviation for two different groups are 3399 ± 131 m/s and 3502 ± 182 m/s, which lead to the average relative errors from the pulse-mode method of 8.38% and 11.15% respectively. The results demonstrate that the WBP method is able to measure thin bone samples whose thickness is comparable or even less than ultrasound wavelength and provides the potential to assess more reliable initial models for the further imaging process.