The spatial decomposition made in this part can be useful to obtain the long-term goals of estimating the slope of a tilted plane and to increase the lateral resolution. It is an extract of Part B1 and deals with the SVD-based inversion of the halfplane echoes. Using the fact that airborne ultrasonic pulses are narrowbanded, a new algorithm for estimating small time-delay is described. This method can be used in conjuction with a normal TOF-estimator. Another area of application is an improved averaging algorithm.
Airborne ultrasound suffers from a jitter which is caused by air movement and temperature gradients.
This jitter can be modelled as a small random time shift. A straightforward averaging will then be a summing of pulses that are not aligned in time which results in a pulse deformation. By estimating the time shift caused by the jitter, all echoes can be time aligned and no pulse deformation will occur when summing them.