A Wavelet and IHS Integration Method to Fuse High Resolution SAR with Moderate Resolution Multispectral Images

Abstract

Synthetic aperture radar (SAR) imaging can be a feasible alternative or a complement to traditional optical remote sensing techniques because it does not depend on solar illumination and weather conditions. The high spatial resolution of SAR, such as the Intermap STAR-3i airborne SAR image with 1.25 m spatial resolution, makes it applicable for high spatial resolution mapping purposes. However, difficulties sometimes exist in the interpretation of SAR images. Image fusion presents an alternative to improve the interpretability of SAR images by fusing the color information from moderate spatial resolution multispectral (MS) images. In this paper, a new fusion method based on the integration of wavelet transform and IHS (Intensity, Hue, and Saturation) transform is proposed for SAR and MS fusion to maintain the spectral content of the original MS image while retaining the spatial detail of the high-resolution SAR image. Three data sets are used to evaluate the proposed fusion method: two sets are airborne SAR images with MS images at different spatial resolutions; the other set is a Radarsat image with a Landsat TM image. The fusion results are evaluated visually and statistically. The evaluation shows that successful results are achieved in the fusion of all SAR and MS images from a variety of sensors with significant spatial and spectral variations by using the proposed image fusion method.