Automated registration of hyperspectral images for precision agriculture

Hyperspectral imagery of the Earth's surface is increasingly being acquired from aerial platforms. The dozens or hundreds of bands acquired by a typical hyperspectral sensor are collected either through a scanning process or by acquiring a sequence of images at different wavelengths. This latter method has the advantage of acquiring coherent images of a scene that are more easily interpretable than a given waveband from a scanning system. However, it takes time to collect these images and some form of image-to-image co-registration is required to match the band-to-band pixel locations and build coherent image cubes. In this paper, we present a Phase Correlation (PC) method to register many bands acquired sequentially at different wavelengths. This method was implemented to recover scaling, rotation, and translation from an airborne hyperspectral imaging system, dubbed the Portable Hyperspectral Tunable Imaging System (PHyTIS). The PC approach is well suited for remotely sensed images acquired from a moving platform, which induces image registration errors due to along- and across-track movement. We were able to register images to within ±1 pixel across entire image cubes obtained from the PHyTIS, which was developed for precision farming applications.