Remote Sensing Image Fast Fourier Transform To The Research And Implementation Of The New Algorithm

Fast Fourier Transforms (FFTs) are efficient algorithms for calculating the discrete fourier transform(DFT), it's the most important approach to many Digital Image Processing algorithms. Traditional algorithms for FFT of huge images are inefficient and the speed is slow, which limit its application.On the basis of analyzing the bottle neck of traditional algorithms, this paper develops a series of approach to improve the efficience in two aspects: one is to speed up the FFT algorithm which is use to compute the FFT of each row and column; another is to improve the speed of file I/O while interconverting the result of FFTs between row and column. The most work is followed:1) A FFTW algorithm is introduced to be used as FFT of image.2) The intermediate result of FFTs is saved to disk in blocks, which optimizes the interconverting of row and column.3) The using of intermediate buffering of file I/O is optimized, which increases the performance of reading and writing large amount of file data.4) A parallel processing is used to enable performing FFT calculating synchronously while file I/O is running.Experiment shows that our algorithm is competitive to many popular image processing software such as PCI and ERDAS.