Spatially sampling effect on fringe phase-shifting detection

One effect of spatially sampling of an image is averaging the image intensity over each pixel. In this paper, this spatial average effect on phase-shifting detection of fringe pattern is investigated. The phase error due to pixel size and sampling rate is formulated. It is shown that lower sampling frequency, for example, 1/4 fringes per pixel for 1-D fringe signal, 1/6 fringes per pixel for 2-D signal, will cause larger measurement error.