Four phase unwrapping algorithms based on fast Fourier transform

In order to recover the noisy wrapped phase map rapidly and accurately, four typical algorithms based on fast Fourier transform, i.e. the algorithms respectively based on fourfast Fourier transforms (4-FFT algorithm), two fast Fourier transforms (2-FFT algorithm), four discrete cosine transforms (4-DCT algorithm) and combination of lateral shearing and Fourier transform (LS-FFT algorithm), are compared through theoretical analysis, computer simulation and experimental verification. The results show that, the 2-FFT algorithm is the fastest, followed by the 4-FFT algorithm, and the LS-FFT algorithm is the slowest. For the strong noisy and slightly under-sampled wrapped phase map obtained by digital holographic experiments, the 4-FFT algorithm performs the best, while the LS-FFT algorithm does the worst.