METHOD AND APPARATUS FOR MEASURING THE THREE DIMENSIONAL STRUCTURE OF A SURFACE

A method includes imaging a surface with at least one imaging sensor, wherein the surface and the imaging sensor are in relative translational motion. The imaging sensor includes a lens having a focal plane aligned at a non-zero angle with respect to an x-y plane of a surface coordinate system. A sequence of images of the surface is registered and stacked along a z direction of a camera coordinate system to form a volume. A sharpness of focus value is determined for each (x,y) location in the volume, wherein the (x,y) locations lie in a plane normal to the z direction of the camera coordinate system. Using the sharpness of focus values, a depth of maximum focus zm along the z direction in the camera coordinate system is determined for each (x,y) location in the volume, and based on the depths of maximum focus zm, a three dimensional location of each point on the surface may be determined.