{"id":991,"date":"2014-01-27T15:00:39","date_gmt":"2014-01-27T06:00:39","guid":{"rendered":"http:\/\/www.lookingatnothing.com\/?p=991"},"modified":"2014-01-27T15:23:47","modified_gmt":"2014-01-27T06:23:47","slug":"new-live-fourier-transform-code","status":"publish","type":"post","link":"https:\/\/lookingatnothing.com\/index.php\/archives\/991","title":{"rendered":"New Live Fourier Transform code"},"content":{"rendered":"

More\u00a0about this next week, but Ingo<\/a> has kindly provided a Windows executable version of one of the latest development builds of the Monte Carlo code (with GUI). While I have not yet had the chance to test it (being on a mac myself), please go ahead and get it from here<\/a>!<\/em><\/p>\n

Some of you may have seen the Live Fourier Transform <\/a>video that was made a while ago. I am happy to tell you that there is now a new, better version out of that program (still rather small and straightforward, though).<\/p>\n

The idea behind this demonstration program is to show the camera image and the (intensity component of) the Fourier transform alongside. This Fourier transform does to the camera image, what X-rays do to matter:\u00a0When X-rays interact with matter, they create an interference pattern which is related to the Fourier transform of the electron density structure in the matter.<\/p>\n

So with this program, I can show you what X-ray scattering and diffraction looks like for a variety of structures. I have been using the previous version in many of my presentations, where the change of pace and the little show appears to be appreciated by the audience.<\/p>\n

The new version uses a much friendlier and faster back-end (OpenCV<\/a>) for capturing and displaying the images. Furthermore, it uses command-line arguments which can be used to adapt most of the internal parameters to suit your camera and\/or needs, and it even works in colour (pointless but fun)!<\/p>\n

\"A<\/a>
A screenshot from the Live Fourier Transform program<\/figcaption><\/figure>\n

I tried compiling it so I could pass around a mac os x application instead of requiring the installation of a python environment (Enthought’s <\/a>the easier one to install) and the OpenCV package (available through the Canopy package manager). Unfortunately, I could not compile it successfully in time for this post due to problems with compiling under the Enthought environment.<\/p>\n

The source is available on a Git DVCSS<\/a>, so community improvements are possible and welcomed!<\/p>\n

The new video has just been uploaded. I skimped a bit on the video correction and visuals, but I hope it is enjoyable nonetheless:
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