Ptychography: Software: SHARP-CAMERA

Sharp Camera Documentation

 

 

 

 

Sharp Camera is used to obtain images from ptychography experiments in real-time. It uses parallelization and GPU computing to achieve the necessary speed. It is designed to reconstruct an image from a set of far-field diffraction patterns, recorded at known sample translations, obtained in an X-ray ptychography experiment.

 

 

 

For the further information, please contact the Sharp development team (sharp-access@lists.lbl.gov), and let us know if you would like to be added to the sharp mailing list for future updates.

 

 

 

 

 

 

 

X-Ray Ptychography:

 

X-ray ptychography is an imaging technique which combines the ease of use of a scanning transmission microscope (STM) with the high resolution of microscopy, without the requirement of high resolution X-ray lenses. It works by focusing beam of X-rays onto a spot in the sample, much like in an STM, but instead of only relying on the total transmission for recovering the image, the scattering from the sample is recorded in the far field.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The recorded pattern is then phased to obtain the final image. The highest resolution attainable is not limited by the size of the focal spot, as in an STM, but only by the numerical aperture and wavelength used, exactly like in microscopy. The phasing procedure in ptychography uses the extent of the overlap between consecutive exposures of the sample, as well as the recorded far field diffraction patterns, to reconstruct a high resolution image of the sample.

 

Options:

 

-i ITER: Run for ITER iterations. Defaults to 10.
-o ITER: Print error metrics every ITER iterations. The default is every iteration.
-r ITER: Refine the illumination every ITER iterations. Defaults to no refinement.
-N REPT: Do REPT independent reconstructions. Defaults to 1.
-f FILE: Write output to FILE. Defaults to writting a new image in the input file


Advanced Options:

-b BETA: beta parameter for RAAR. Defaults to 0.75.
-g ITER: Do global synchronizations every ITER iterations. Defaults to every iteration.
-n VAL: Set noise parameter for illumination cutoff. Defaults to 1e-2.
-s: silence all output.
-B: relaxed fourier projection.
-T ITER: Recalculate background every ITER iterations. Off by default.
-I: enforce intensities when refining illumination.
-M: enforce fourier mask when refining illumination.
-A: data projector tolerance (error threshold for stopping a reconstruction). Defaults to 5e-5.
-O: overlap projector tolerance. Defaults to 5e-5.
-U: solution error tolerance. Defaults to 5e-4.
-S: stagnation tolerance. Defaults to 5e-5.
-C: no cropping of output image when saving to file


Debugging Options:

-D: output debug messages.
-t: output the time the solver takes.
-w SIDE: turn on frame wrap around. Requires square object of SIDE pixels.
-R SEED: Use SEED as the random seed.

Input:

  • CXI Input Format For Ptychography Reconstruction - input_cxi.pdf

 

Dependencies

 

Workshop Presentations

 

 

 

For the further information, please contact the Sharp development team (sharp-access@lists.lbl.gov), and let us know if you would like to be added to the sharp mailing list for future updates.