An accurate aperture synthesis method in generalized phase-shifting interferometry is suggested to improve the quality of the reconstructed object wavefront by stitching both the phase and the real amplitude of the object wave on the recording plane. Since the phase distribution affects the reconstruction of the original object wavefront, phase stitching is also important in aperture synthesis. Double correlations are used to find the proper relative locations and correct the phase error of subwavefronts on the recording plane. By using phase correction, the phase distributions of subwavefronts are combined perfectly. Corresponding optical experimental results have verified the effectiveness of this method, which can stitch not only the real amplitudes but also the phases of the complex amplitudes of the object wave on the recording plane and improve the quality of the reconstructed object image. (C) 2013 Optical Society of America