During the operation of the EAST device, the surface morphology of the first wall in will change due to the erosion and redeposition from plasma-wall interaction (PWI). In this paper, a novel phase extraction approach using only single interferogram based on twice Hilbert transform (THT) has been proposed and implemented. The current approach has a significant advance for eliminating the phase-shifting errors in principle, but the problems of phase flipping and loss due to ignoring non-physical negative frequency spectrum must to be overcome. To address these problems a judgement method is proposed in current investigation to distinguish the regions of the negative spatial frequency. Then a binary matrix was developed to modify the wrapped phase of the measured interferogram. The validation of the proposed THT approach has been demonstrated by the micro-morphology reconstruction of laser ablation craters on molybdenum (Mo) and tungsten (W) tiles, which are commonly used as the first wall in EAST device. Results indicate that the THT approach has a reasonable measurement accuracy with relative errors around 10%. Also, the current THT approach presents an enhanced robust under the EAST-like vibrational environments.