As a newly developed coherent diffraction-imaging (CDI) imaging method, the ptychographical iterative engine not only can bypass the difficulty of having high-quality optics in x-ray microscopy by a numerical reconstruction algorithm, but also has obvious advantages on traditional CDI methods in both converging speeds and view fields. However, like in the other CDI methods, the reconstruction of the image from the intensity data of a weakly diffracting specimen is still difficult because of the low signal to noise ratio. To improve this situation, a modification to the currently used algorithms is suggested to double the presence of high spatial frequencies in the diffraction pattern and accordingly to enhance the contrast and fine details of the reconstructions. The simulation and experimental results are presented, and the results can be extended to other CDI methods also.