1. A computerized stereology system, comprising: an imager for capturing a Z-stack of images of a three-dimensional (3D) object, the Z-stack of images being a sequence of images of the 3D object captured in increments having a step size along a z-axis of the 3D object; and a processor configured to identify a top and a bottom boundary of each image of the Z-stack by performing a depth of focus analysis to determine just-out-of-focus focal planes of images within the Z-stack, the just-out-of-focus focal planes establishing boundaries with no interpolation between images within the z-stack of images.