Surface landmine detection in airborne images using the circular harmonics transform

Multi-band medium wave infrared (MWIR) image data collected from the Lightweight Airborne multispectral Minefield Detection-Interim (LAMD-I) program is examined for the detection of surface landmines. Because the orientation of the image acquisition from aircraft with respect to the mine and the minefield is unknown, there is a need to develop an orientation invariant-based approach for landmine and minefield detection. A rotation invariant circular harmonics transform (CHT)-based approach is presented for surface landmine detection. The magnitude information from the CHT is used for finding mine-like regions within the MWIR images. A three-tiered hierarchical thresholding technique provides the basis for highlighting potential surface landmines. Mine shape and size information are used for generating landmine confidence values. Surface landmine detection capability is presented for 82 MWIR broadband images with sand and short and long grass terrain conditions for daytime and nighttime acquired MWIR image data. Receiver operator characteristic (ROC) curves are used for comparing experimental results from this technique with an existing an adaptive multi-band CFAR detector (RX approach).