1. An optical method for determining contours of an object, comprising: (1) illuminating a reference surface comprising an orthogonal grating, via a first projector; (2) capturing a first reference image of the reference surface, via a processing unit coupled with a camera and operative to receive video signals from the camera; (3) illuminating the reference surface, via a second projector; (4) capturing a second reference image of the reference surface, via the processing unit; (5) subtracting the first reference image from the second reference image, via the processing unit, to obtain a first reference phase image; (6) illuminating the object, via the first projector; (7) capturing a first object image, via the processing unit; (8) illuminating the object, via the second projector; (9) capturing a second object image, via the processing unit; (10) subtracting the first object image from the second object image, via the processing unit, to obtain a first object phase image; and (11) subtracting the first object phase image from the first reference phase image, via the processing unit, to obtain a first contour image comprising the contours of the object.