Ptychography (ptycho)
Ptychography is a scanning x-ray microscopy method with coherent illumination. The word ptychography was derived from the Greek words ptyché (πτυχή = fold) and gráphein (γράφειν = to write). It is an imaging technique consisting of an acquisition setup and a data inversion step. In this technique, the sample is scanned with a focused coherent x-ray beam. However, at each position of the scan, a two-dimensional diffraction pattern is recorded in the far field regime. Using a numerical reconstruction algorithm, both the object's complex transmissions function and the complex illuminating wavefield can be reconstructed from the series of diffraction patterns. A set of diffracted images is measured by illuminating the object of interest at different positions. The object is translated in a 2D plane. The 4D acquired data (each 2D position is an image) is computed with a so-called inversion algorithm to form an image of the studied object. This modality has the advantage of not depending on a good quality lens, as it does not require any.
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