Digital sinusoidal fringe pattern generation: Defocusing binary patterns VS focusing sinusoidal patterns

There are two approaches to generate sinusoidal fringe patterns with a digital-light-processing (DLP) projector: defocusing binary patterns (DBP), and focusing sinusoidal patterns (FSP). This paper will compare the potential errors for both methods induced by the following factors: (1) degree of defocusing, (2) exposure time, (3) synchronization, and (4) projector's nonlinear gamma. Experiments show that in most scenarios, the error for the DBP method is smaller than that of the FSP method. Therefore, generating a sinusoidal fringe image using a DBP method seems to be appealing.