A robust algorithm based on phase congruency for optical and SAR image registration in suburban areas

Abstract

Automatic registration of optical and synthetic aperture radar (SAR) images is a challenging task due to the influence of SAR speckle noise and nonlinear radiometric differences. This study proposes a robust algorithm based on phase congruency to register optical and SAR images (ROS‐PC). It consists of a uniform Harris feature detection method based on multi‐moment of the phase congruency map (UMPC‐Harris) and a local feature descriptor based on the histogram of phase congruency orientation on multi‐scale max amplitude index maps (HOSMI). The UMPC‐ Harris detects corners and edge points based on a voting strategy, the multi‐moment of phase congruency maps, and an overlapping block strategy, which is used to detect stable and uniformly distributed keypoints. Subsequently, HOSMI is derived for a keypoint by utilizing the histogram of phase congruency orientation on multi‐scale max amplitude index maps, which effectively increases the discriminability and robustness of the final descriptor. Finally, experimental results obtained using simulated images show that the UMPC‐Harris detector has a superior repeatability rate. The image registration results obtained on test images show that the ROS‐PC is robust against SAR speckle noise and nonlinear radiometric differences. The ROS‐PC can tolerate some rotational and scale changes.