Abstract

In this paper, we propose a new approach for sub-pixel co-registration based on Fourier phase correlation combined with the Harris detector. Due to the limitation of the standard phase correlation method to achieve only pixel-level accuracy, another approach is required to reach sub-pixel matching precision. We first applied the Harris corner detector to extract corners from both references and sensed images. Then, we identified their corresponding points using phase correlation between the image pairs. To achieve sub-pixel registration accuracy, two optimization algorithms were used. The effectiveness of the proposed method was tested with very high-resolution (VHR) remote sensing images, including Pleiades satellite images and aerial imagery. Compared with the speeded-up robust features (SURF)-based method, phase correlation with the Blackman window function produced 91% more matches with high reliability. Moreover, the results of the optimization analysis have revealed that Nelder–Mead algorithm performs better than the two-point step size gradient algorithm regarding localization accuracy and computation time. The proposed approach achieves better accuracy than 0.5 pixels and outperforms the speeded-up robust features (SURF)-based method. It can achieve sub-pixel accuracy in the presence of noise and produces large numbers of correct matching points.

Highlights

  • We evaluated the overall performance of our proposed co-registration workflow using the precision of phase matching and the root mean square error (RMSE) of measured displacements before and after the registration

  • The reliability and validity of the proposed method were evaluated with two sets of very high-resolution (VHR) remote sensing images acquired from different sensors

  • Very high-resolution remote sensing images usually contain obvious geometric distortion in local areas introduced by increasing the spatial resolution and lowering the altitude of the sensors

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Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The image registration process is an important task in image processing in applications such as automatic change detection, data fusion, motion tracking, and image mosaicking. When images of the same location taken at different dates or from different viewpoints need to be compared, they must be geometrically registered to one another. In the process of image registration, the image to be registered, called the sensed image, is aligned against a reference image. Accurate registration allows detection and monitoring of changes between images that might otherwise be difficult to ascertain without sub-pixel misregistration

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