Apparatus and methods for surface contour measurements

A method for mitigating the effects of speckle on a measurement of a point on a surface of an object, said method comprising the steps of:

• a) generating a coherent fringe pattern;
• b) projecting the coherent fringe pattern along an optical path onto the surface of the object such that the fringe pattern substantially grazes the surface of the object;
• and
• c) detecting the fringe pattern and the speckle in an image of the surface of the object, wherein a normal to the surface of the object is substantially orthogonal to said optical path.

A method for projecting fringes onto a surface of an object, said method comprising the steps of:

• a) providing two sources of radiation separated by a distance, each of said sources having a spectral distribution and being coherent with respect to the other of said sources;
• b) illuminating said point on said surface of said object with said radiation from each of said sources;
• c) moving one of said sources relative to the other of said sources;
• and
• d) detecting radiation scattered by said point on said surface of said object.