  A simple method of constructing the 3D surface of non-transparent
micro-objects by extending the depth-of-field on the whole attainable surface
is presented. The series of images of a sample are recorded by the sequential
movement of the sample with respect to the microscope focus. The portions of
the surface of the sample appear in focus in the different images in the
series. The indexed series of the in-focus portions of the sample surface is
combined in one sharp 2D image and interpolated into the 3D surface
representing the surface of an original micro-object. For an image acquisition
and processing we use a conventional upright stage microscope that is operated
manually, the inexpensive Helicon Focus software, and the open source MeshLab
software. Three objects were tested: an inclined flat glass slide with an
imprinted 10 um calibration grid, a regular metal 100x100 per inch mesh, and a
highly irregular surface of a material known as a porous electrode used in
polyelectrolyte fuel cells. The accuracy of the reconstruction of the image
features was found to be ~ 0.01 for the heights of ~ 100 um with the
corresponding image acquisition time being ~ 10 min.
