NSCT与GS变换的资源三号卫星数据融合方法研究与应用

A Research on Fusion Method for ZY-3 Satellite Data Based on NSCT and GS Transform

资源三号卫星遥感数据是一种新型遥感影像,目前尚未有一种专门适用于资源三号卫星融合的方法。因此,提出了一种非下采样Contourlet变换(NSCT)与Gram-Schmidt(GS)变换相结合的融合方法,将非下采样Contourlet变换增强的空间信息用于补充具有高保真度Gram-Schmidt变换融合算法在影像清晰度方面的不足。采用线性回归的方法模拟低分辨率全色影像,将高分辨率全色影像、低分辨率全色影像及两者差值的细节影像分别进行非下采样Contourlet变换,对所得的高低频系数采取不同的融合策略进行自适应融合处理,得到新的全色影像。由低分辨率全色影像取代GS正变换第一分量,非下采样Contourlet变换得到的全色影像取代GS反变换第一分量,进行Gram-Schmidt正交变换,得到融合影像。与大多存在光谱扭曲的传统融合方法相比较,本文方法在光谱保真度、空间清晰度及地物分类精度方面都有明显的优势,说明该融合方法是一种适合资源三号卫星数据多光谱与全色影像融合的方法。

ZY-3 satellite data, which is a new type of remote sensing imagery, has not yet owned a specific imag-es fusion method. This paper proposed a new fusion algorithm based on the nonsubsampled Contourlet transform and Gram-Schmidt （GS） transform according to the characteristics of CBERS-03 data. Firstly, the linear regres-sion method was used to generate the low-resolution panchromatic image with respect to the low-frequency pix-els. Then, the nonsubsampled Contourlet transform was applied respectively on the high-resolution panchromatic image, the low-resolution panchromatic image, and the image generated from their differences, to generate high frequency and low frequency coefficients. With these coefficients, a new panchromatic image was produced by using adaptive fusion strategies. At last, the fused image was obtained through GS orthogonal transformation, by replacing the first component of GS positive transformation with the low-resolution panchromatic image, and re-placing the first component of GS inverse transformation with the newly generated panchromatic image. Com-pared with the traditional image fusion methods, which always have defects of spectral distortion, the proposed method had obvious advantages in terms of spectral fidelity, spatial resolution and classification accuracy. In con-clusion, the proposed method is appropriate for images fusion on the ZY-3 multispectral and high resolution data.