A new technique for phase demodulation from a single fringe-pattern image is presented in this paper. The method locates the extremes of fringes′ intensity distribution,and converts the intermediate gray-values into values between -1 and 1 using linear interpolation. Based on the extremes map,a wrapped phase distribution is demodulated from a single fringe-pattern and the phase values are computed by using an arcos mode rather than the traditional atan2 mode.Through the new method, wrapped phase values can be efficiently extracted from a singgle fringe-pattern without the need of carrier fringers.......