Modified filter design to optimize the synthetic reference wave in the generalized phase contrast method

We propose a modified design of the phase contrast filter to optimize the synthetic reference wave (SRW) in the generalized phase contrast method. The modified filter consists of a π-phase shifting disk surrounded by an annular ring to modulate the curvature of the intensity distribution generally associated with the SRW. We identify optimal filter parameters to yield a uniform intensity distribution within the working area. Performance tests where done for both periodic and arbitrary input phase patterns using the optimal filter parameters. Assessment of the quality of the projected intensity patterns suggests a more uniform intensity distribution at the output when using the modified filter.