I found a free program that can be used to quickly play with molecule image FFTs.
Install Jimage http://rsbweb.nih.gov/ij/ Load for example my image http://www.ruppweb.org/images/transparent_molecule.gif into Jimage Select FFT, select option complex FFT, and execute. Zoom in to the center a few times, and you get a real coarse pixelated image that looks like my transform. I recall having to scale the FFT range when F90 hardcoding the FT which I used to calculate the raw data which were then contour-plotted in Mathcad. Note that the resulting FFT has 2 parts (use the slider on the bottom), the real part is always centrosymmetric, while the complex (phase) part is not. Probably needs some tweaking to be really useful for presentation purpose. BR -----Original Message----- From: Bernhard Rupp (Hofkristallrat a.D.) [mailto:[email protected]] Sent: Friday, January 06, 2012 12:35 PM Subject: Re: Molecular Transform Superimposed on a Dataset This may give some idea: Illustration of a molecule and its cosine transform: http://www.ruppweb.org/garland/gallery/Ch6/pages/Biomolecular_Crystallograph y_Fig_6-16.htm and sampled by lattice points http://www.ruppweb.org/garland/gallery/Ch6/pages/Biomolecular_Crystallograph y_Fig_6-01_PART3.htm BR
