.When using the Fourier transform method to demodulate the phase from an interferogram, the Gibbs effect often occurs at the edge of the phase picture. Fringe extrapolation is a straightforward method to suppress the Gibbs effect. Currently, many algorithms are used in fringe extrapolation, and exemplar-based methods are one such alternative. However, the traditional exemplar-based algorithm is based on the Criminisi algorithm, which is extremely time-consuming. In this study, the structure-guided image-completion method was applied to interferogram extrapolation. Simulations and experiments show that the new method reduces computer memory requirements and saves computing time. Compared with extrapolation using the Criminisi algorithm, the speed can be increased by tens or even hundreds of times.

Existing aspheric testing methods are sensitive to environmental effects. The digital moire interferometric technique (DMIT) demodulates surface errors from a single interferogram by building a virtual interferometer to avoid environmental effects. This method requires the actual carrier and the virtual carrier to be the same. In this paper, the effect of carrier deviation on DMIT is investigated. It was found that the carrier deviation would extend the spectrum of low-frequency information. Spectrum expansion can deteriorate the noise immunity of DMIT. Spectrum expansion may also lead to spectrum overlap. Method for determining the actual carrier from frequency domain is analyzed. A carrier alignment algorithm is proposed, and the simulation results deviate from the true value by only 6%.