Two-Stage Pansharpening Based on Multi-Level Detail Injection Network

Pansharpening is an effective technology to obtain high resolution multispectral (HRMS) images by fusing low resolution multispectral (LRMS) images and high resolution panchromatic (PAN) images. With the rapid development of deep learning, some pansharpening methods based on deep learning have been proposed. Although fused images are greatly improved, there are still some areas for improvement. For example, the spectral preservation is not good enough and the details of fused images are not rich enough. To address the above problems, a two-stage pansharpening method based on convolutional neural network (CNN) is proposed. In the first stage, image super-resolution technology with residual block is used to enhance LRMS. In order to preserve spectra, inspired by the SAM (spectral angle mapper) index, a new spectral loss function is proposed. The second stage is the fusion stage. Detail injection block is proposed by combining detail injection and CNN in this stage. Experiments on WorldView2 and GeoEye1 images demonstrate that our fused images present more spatial details and better spectra by comparing with existing methods.