Digitized optical microscopy with extended depth of field

Partial information about a 3-D object, such as a stereoscopic pair of projections, is sometimes more desirable than the whole 3-D information. We demonstrate how to (1) synthesize a clear projection of a small complex object from a succession of digitized images obtained by moving the object stepwise through the focal plane, (2) synthesize a clear projection of a selected layer of a biological specimen composed of multiple curved layers, and (3) measure precisely the 3-D surface of a small object.