Elastic registration for airborne multispectral line scanners

The multispectral line scanner is one of the most popular payloads for aerial remote sensing (RS) applications. Scanners with large field of view (FOV) improve efficiency in Earth observation. Small-volume instruments with a short focal length and a large FOV, however, may bring a problem: different nonlinear warping and local transformation exist between bands. Alignment accuracy of bands is a criterion impacting product quality in RS. A band-to-band elastic image registration method is proposed for solving the problem. Rather than ignoring the intensity variation and carrying out an intensity-based registration between bands straightforwardly, we construct feature images and use them to conduct an intensity-based elastic image registration. In this method, the idea of the inverse compositional algorithm is employed and expanded when dealing with local warping, and a smoothness constraint is also added in this procedure. Experimental results show that the proposed band-to-band registration method works well both visually and quantitatively. The outstanding performance of the method also encourages potential applications for other new types of airborne multispectral imagers.