1. A system for measuring displacement of an object surface comprising: a displacement sensor that projects a line on the object surface and receives light from the projected line at an imager in a manner defines a plurality of displacement values in a height direction; a vision system processor that processes at least two rows of displacement value image data from the imager and defines a plurality of patches with respect to the displacement value image data, the patches being oriented to register features of the image data; and a displacement sensor process performed by the processor that averages the displacement values in each of the patches to obtain an average patch displacement value.