Ptychography simulator
An interactive simulator of ePIE, the iterative phase-retrieval engine behind ptychographic imaging.
Acoherent sourceA coherent monochromatic beam, laser, visible-light, electron, or X-ray. Well-defined phase across the wavefront is what makes downstream phase retrieval possible.
Bsample · probe at rjThe probe P illuminates a patch of the unknown complex object O at scan position r_j. Adjacent positions overlap; that redundancy is the source of phase information.
Cdetector · far fieldThe far-field detector records intensity only, |F{P · O}|². Phase is destroyed at this step; the algorithm has to recover it from the overlap between scan positions.
data acquisition
drag · scroll
ground truth · object
diffraction pattern
reconstructed object
reconstructed probe
probe
overlap
noise
5×
acquiring
—data error‖√I − |Ψ|‖
—convergence
—Drop overlap to 50%. Convergence stalls; overlap carries the phase information.
Switch noise to high. The data error settles to a non-zero floor instead of going to zero.
Use a 32 px probe. More scan positions, sharper features, but each frame carries less information.
ePIE loop
- 1exit wave at position j
- 2Fraunhofer propagation
- 3modulus constraint (measurement)
- 4inverse propagation
- 5object update
- 6probe update