Multispectral and panchromatic image fusion using a joint spatial domain and transform domain for improved DFRNT

The use of traditional spatial domain fusion methods such as intensity-hue-saturation (IHS) and principal component analysis (PCA) achieve good spatial quality but often lead to spectral distortion. Use of discrete fractional random transform (DFRNT) fusion, which is a transform domain method proposed by the authors before, can maintain the high spectral information. Hence, in this paper we propose using the respective advantages of DFRNT and IHS or PCA, via combined IHS-DFRNT and PCA-DFRNT approaches to obtain good spectral quality and high spatial quality, which is also for improved DFRNT method. At the same time, instead of fusion in the spatial domain or the transform domain, respectively, as in the conventional methods, the proposed IHS-DFRNT and PCA-DFRNT approaches are fused in a kind of joint spatial domain and transform domain. Moreover, different random distributions of DFRNT produce different fusion results which can meet different application demands. The fused images are found to preserve both the spectral information of the multispectral image and the high spatial information of the panchromatic image. Especially, the proposed combined methods are much faster and keep better comprehensive information than DFRNT. Objective quantitative evaluation indexes are also used to illustrate the effectiveness of the proposed methods.