  We study digital images of r-regular objects where a pixel is black if it is
completely inside the object, white if it is completely inside the complement
of the object, and grey otherwise. We call such images trinary. We discuss
possible configurations of pixels in trinary images of r-regular objects at
certain resolutions and propose a method for reconstructing objects from such
images. We show that the reconstructed object is close to the original object
in Hausdorff norm, and that there is a homeomorphism of the plane taking the
reconstructed set to the original.
