  A method is proposed for high-resolution, three-dimensional reconstruction of
internal structure of objects from planar transmission images. The described
approach can be used with any form of radiation or matter waves, in principle,
provided that the depth of field is smaller than the thickness of the sample.
The physical optics basis for the method is elucidated and the reconstruction
algorithm is presented in detail. A simulated example demonstrates an
application of the method to three-dimensional electron transmission imaging of
a nanoparticle under realistic radiation dose and spatial resolution
constraints. It is envisaged that the method can be applicable in
high-resolution transmission electron microscopy, soft X-ray microscopy,
ultrasound imaging and other areas.
