Optical-to-SAR Image Matching Using Multiscale Masked Structure Features

Automatic and precise matching between optical and synthetic aperture radar (SAR) images is still a challenging task because of significant radiation and texture differences between such images. Recently, structure feature-based methods are popular for the matching of SAR and optical images. However, current structure descriptors include many noninformative features, which degrade their matching performance. To address that, we present a robust matching method by a multiscale masked structure feature representation. We first extract pixelwise gradient structure features on multiple scales of images. Then, a mask is constructed according to large contours of an image, which is used to increase the contribution of the main structure region and alleviate the influence of noninformative regions. Finally, a fast template scheme based on fast Fourier transform (FFT) is employed to obtain correspondences. The proposed method is tested using the optical and SAR images from the Sentinel and GaoFen sensors. Experiment results show that the proposed method significantly improves the matching performance compared with the state-of-the-art methods, especially for the images with poor structure features.