Abstract: Phase profilometry inspection system has a pattern projection assembly, a detection assembly imaging a plurality of first light intensity patterns on the object and determining a first height of the object, and an absolute object height determination unit combining said first height with at least one second object height measurement to provides absolute height determination of desired points of said object. The first height is determined within an order of said first light intensity pattern and does not resolve absolute height. The second object height measurement can be done also by projecting a light intensity pattern of a lower spatial frequency than the first patterns.

Abstract: The present invention provides a Fast Moiré Interferometry (FMI) method and system for measuring the height profile of an object with an increase precision by combining a plurality of image features. In one large aspect of the invention, two or several images are acquired under different conditions, to yield two or several images: Ia?(x,y), Ia?(x,y), . . . instead of one single image Ia(x,y). This is repeated for images obtained with different grating projection “b”, “c”, and “d”. These images are combined to provide combined images or a merged phase value, which are used to determine the object height profile.