In order to measure and correct a distorted image,a vertical Ronchi carrier-fringe pattern is used as measuring template,and a distorted grating pattern is captured by the imaging system.Fourier transform method is adopted to analyze the spectrum of the distorted fringe pattern,and the fundamental spectrum is extracted by filtering.An ideal image is obtained from the central region of the distorted image,where there is no distortion,and the unwrapped phase distribution and radial wrapped phase distribution are obtained by fringe analysis.The radial phase distribution is converted to the radial distortion distribution,and the corrected image is obtained utilizing the radial distortion distribution and bilinearity interpolation.The experiment results show that the method is valid.