Fourier Transformation
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Printed Date: November 22 2024 at 02:39
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Topic: Fourier Transformation
Posted By: MikeEnRegalia
Subject: Fourier Transformation
Date Posted: May 28 2007 at 03:14
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Fourier transformation is a technology used in different areas ... one of them is audio compression/storage. I found a nice page which contains an applet that allows you to experiment with this algorithm (using pictures instead of audio, but the principle is the same for any data, be it audio, video or images): http://homepages.inf.ed.ac.uk/rbf/HIPR2/fftdemo.htm - http://homepages.inf.ed.ac.uk/rbf/HIPR2/fftdemo.htm The applet is a bit technical ... and of course this whole subject is. The reason for me posting this is that the applet shows that Fourier transformation really works ... and how it does its job. You'll see an image, you can perform Fourier transformation on the image and see the result, and you can perform the inverse Fourier transformation to put the image back together. You can also have a look at this page which kind of gives you the "skinny" on Fourier transformation: http://cns-alumni.bu.edu/~slehar/fourier/fourier.html - http://cns-alumni.bu.edu/~slehar/fourier/fourier.html The high pass / low pass filters intrigued me, and you can test those with the applet and see the effects. ------------- https://awesomeprog.com/users/Mike" rel="nofollow">Recently listened to: 
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Replies:
Posted By: Angelo
Date Posted: May 28 2007 at 16:52
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Interesting!!! When I was doing my graduation project, a PhD student in the department where I worked was working on image compression using Fourier transformations and some other mathematical operations. At some point he had a better compression rate then JPEG, and lossless as well. Pity that even on todays PCs his compression algorithm is still time consuming (this was almost 14 years ago). ------------- http://www.iskcrocks.com" rel="nofollow - ISKC Rock Radio I stopped blogging and reviewing - so won't be handling requests. Promo's for ariplay can be sent to [email protected] |
Posted By: Dean
Date Posted: June 07 2007 at 06:47
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A few years ago I wrote an Microsoft Excel module for computing FFT's. Excel is not the best tool for DSP, but I used it to demonstrate to a non-believer that clock-jitter affects the Signal-to-noise ratio of DAC converters.
you can download the module from here: http://members.aol.com/deancr/tech/Module1.bas - members.aol.com/deancr/tech/Module1.bas or the Excel spreadsheet with the module pre-loaded here: http://members.aol.com/deancr/tech/FFT.XLS - members.aol.com/deancr/tech/FFT.XLS ------------- What? |