快速傅里叶变换(FFT )是遥感影像处理的基础方法,随着高光谱、高空间和高时间分辨率遥感影像获取能力的提升,如何利用快速傅里叶变换技术快速有效地处理巨幅遥感影像是当前遥感影像处理技术中的重要环节和研究热点。傅里叶变换算法FFT是基本的图像处理算法之一,该算法可进行遥感影像的条带噪声去除、影像压缩和影像配准处理等多种用途。CUFFT函数库是NVIDIA 公司提供的基于GPU 的FFT算法库,FFTW是由MIT科学实验室计算机组在PC平台上开发的基于CPU 的FFT 算法,是目前在基于CPU的运行速度最快的FFT算法函数库,这两种实现共有的问题是当可用内存或显存的容量小于图像容量时,就会出现内存或显存溢出。针对这种问题,提出了一种基于GPU 和分块技术的巨幅遥感影像快速傅里叶变换(huge remote fast Fourier transform ,HRFFT )算法。通过对CUDA的CUFFT函数库中的FFT算法进行改进,解决了巨幅图像内存或显存溢出的问题,并结合 HJ-1A卫星的CCD影像,通过实验与其他算法进行了对比,证明了该方法的合理性。在实际应用中,利用本文提出的 HRFFT算法,改善了影像处理的效果,提高了遥感影像的质量,同时加快了影像处理的速度,节省了计算时间,取得了较好的效果。
Fast Fourier transforms (FFT ) is a basic approach to remote sensing image processing .With the improvement of capacity of remote sensing image capture with the features of hyperspectrum ,high spatial res-olution and high temporal resolution ,how to use FFT technology to efficiently process huge remote sensing image becomes the critical step and research hot spot of current image processing technology .FFT algorithm , one of the basic algorithms of image processing ,can be used for stripe noise removal ,image compression ,im-age registration ,etc .in processing remote sensing image .CUFFT function library is the FFT algorithm li-brary based on CPU and FFTW .FFTW is a FFT algorithm developed based on CPU in PC platform ,and is currently the fastest CPU based FFT algorithm function library .However there is a common problem that once the available memory or memory is less than the capacity of image ,there will be out of memory or memo-ry overflow when using the above two methods to realize image FFT arithmetic .To address this problem ,a CPU and partitioning technology based Huge Remote Fast Fourier Transform (HRFFT)algorithm is proposed in this paper .By improving the FFT algorithm in CUFFT function library ,the problem of out of memory and memory overflow is solved .Moreover ,this method is proved rational by experiment combined with the CCD image of HJ-1A satellite .When applied to practical image processing ,it improves effect of the image process-ing ,speeds up the processing ,which saves the time of computation and achieves sound result .