Digital reconstruction of three-dimensional serially sectioned optical images

The nature of out-of-focus noise is analyzed and linear filtering approaches are demonstrated for minimizing its effect. The analysis is based on concepts of geometrical optics, and takes into account the passage of light through the object. The object is assumed to be nondiffractive and to have low contrast. These assumptions, although not usually met in practice, are not overly restrictive. Experience shows that even dark, diffractive objects show substantial improvement after filtering. Sample images of a pollen grain and a rat pancreas islet are used to demonstrate the efficacy of the technique