An ultrasonic method for 3D reconstruction of surface topography

Abstract

This study uses an acoustic technique to determine the surface topography for three target objects. Ultrasound is used to define the 3D surface of a wrench, the face of a British twenty-pence coin (20p) that features the profile of Queen Elizabeth II and a US five-cent coin. A single transducer is used to automatically scan the target region, in order to produce a matrix of the point-to-point reflected amplitude data. This work not only showed the surface topography of the targets as a 3D image but also scaled up the height of the particular local surface, which proves that the signal processing method can be applied to make special display treatment for the local area of interest. The experimental process and results perform an attempt method for 3D image reconstruction. Spatial resolution is important for the production of 3D images. For the three experiments, the transducer moves in 0.1 mm steps, which give tens of thousands of scanned data points within the given region. The scale of the surface topography is adjusted by recalibrating the reflected signals. The maps show the reflection coefficient for the two kinds of coins, varied from 0.74 to 0.99.