Measurements of surface texture using ultrasound

A new ultrasonic spectroscopic technique has been developed to measure the gross surface texture of materials. A surface roughness coefficient has been introduced which specifies the texture of a surface on a quantitative basis. Comprehensive theoretical models have been developed to study the effect of surface texture on reflected ultrasonic pulses from a rough surface. The measurement technique is based on examining the frequency spectrum of the received signals in comparison to the theoretical models. A minimisation function obtains the best match between theoretical models and actual measurements such that the resultant coefficient generated corresponding to the best match represents the surface roughness. Although the technique developed was intended to characterise materials having characteristic surface conditions such as that found in crystalline deposits, the technique may be used in general applications including automated inspection systems