Illumination aspects of sparse line arrays for 3D terahertz imaging

Terahertz imaging solutions for industrial non-destructive testing applications receive an increasing attention. Besides the need for real-time acquisition and image processing, 3D feature localization and large field of views of several tenths to a few meters are in the focus of interest. For this purposes sparse line arrays of transmitters (Tx) and receivers (Rx) offer an optimal approach to reduce costs, hardware complexity and potentially the required measurement time of the system, while providing a comparable imaging quality to full array based approaches. But in the presence of dominant specular reflections, sparse arrays can lead to an inhomogeneous illumination which impairs images and hampers their correct interpretation. We propose an experimentally verified method to simulative asses the design of sparse line arrays, taking in consideration the scattering characteristics of the object under test.