Surface Feature Mapping Using High-Resolution C-Scan Ultrasonography

High resolution C-scan ultrasonography is presented as a preferred approach to traditional optical scanning techniques for obtaining images of surface topology. An overview and analysis of the more classical approaches using optical data acquisition devices is made. These devices have limited capabilities and must operate in 'optically sterile' environments. A high resolution, high speed, ultrasonic C-scan is proposed as an alternative to the traditional optical approach of image acquisition. The performance of the proposed system is shown to be invariant to the contaminents that degrade optical based images. Results are presented using data obtained from an experimental model of the system. Also discussed are additional capabilities not obtainable with the optical systems and a separate post processing feature extraction algorithm. The algorithm is based upon two-dimensional spatial frequency analysis and is introduced as the logical progression in the overall development of a 'smart' sensor for feature extraction based on ultrasound.