BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Sourcecode 2D-FFT Goto page 1, 2  Next          BorlandTalk.com Forum Index -> Delphi Graphics View previous topic :: View next topic   Author Message Markus Guest Posted: Mon Nov 06, 2006 1:28 am    Post subject: Sourcecode 2D-FFT Hallo, I am looking for a sourcecode of a 2 dimensional FFT. But not with an included DLL. I want to have real Code. Does anybody know where I can get such Code? Yours, Markus Back to top John Herbster Guest Posted: Mon Nov 06, 2006 3:18 am    Post subject: Re: Sourcecode 2D-FFT "Markus" <warenhandel (AT) gmx (DOT) de> wrote Quote: I am looking for source code of a 2 dimensional FFT. But not with an included DLL. I want to have real code. ... Markus, You ought to be able to find the source code for the procedure HARM from the old IBM Scientific Subroutine Library somewhere. You might have to translate it from the original Fortran. As I recall, it would do one, two, or three dimensions. Rgds, JohnH Back to top Nils Haeck Guest Posted: Mon Nov 06, 2006 5:12 am    Post subject: Re: Sourcecode 2D-FFT Hi Markus, I wrote a complex FFT routine that can also be used for 2D: http://www.simdesign.nl/fft.html Note this is free software but I provide *no* support. I would recommend to read this book: http://www.dspguide.com/ (free online PDF version is available) For 2D FFT it is very convenient to use the complex version. Also, my FFT routine is "mixed radix" meaning it can be used on other dimensions than powers of 2. You do a 2D FFT by first doing a 1D FFT on all rows (scanlines), then a 1D FFT on all columns. I actually have a 2D FFT component as well but it's part of my image processing lib that I don't sell. It also uses above. Nils Haeck www.simdesign.nl "Markus" <warenhandel (AT) gmx (DOT) de> schreef in bericht news:454e3b61$1 (AT) newsgroups (DOT) borland.com... Quote: Hallo, I am looking for a sourcecode of a 2 dimensional FFT. But not with an included DLL. I want to have real Code. Does anybody know where I can get such Code? Yours, Markus Back to top Markus Guest Posted: Mon Nov 06, 2006 4:47 pm    Post subject: Re: Sourcecode 2D-FFT "Nils Haeck" Hi Nils, Thank you very much for your Info and the Code. Quote: You do a 2D FFT by first doing a 1D FFT on all rows (scanlines), then a 1D FFT on all columns. The second FFT on the coloumns on the original Data or on the Data from the first FFT on the rows? Yours, Markus Back to top Nils Haeck Guest Posted: Mon Nov 06, 2006 10:44 pm    Post subject: Re: Sourcecode 2D-FFT Quote: The second FFT on the coloumns on the original Data or on the Data from the first FFT on the rows? On the result of the first operation :) Nils Back to top Markus Guest Posted: Mon Nov 06, 2006 11:39 pm    Post subject: Re: Sourcecode 2D-FFT "Nils Haeck" Quote: The second FFT on the coloumns on the original Data or on the Data from the first FFT on the rows? On the result of the first operation ah. Thx. Thats what I needed to know =) Back to top Nils Haeck Guest Posted: Tue Nov 07, 2006 2:00 am    Post subject: Re: Sourcecode 2D-FFT Actually it doesn't matter if you do rows first, then columns, or columns first, then rows. The result will be the same (except for small roundoff errors). It's one of the mathematical properties of a 2D FFT. Nils Back to top Jens Gruschel Guest Posted: Tue Nov 14, 2006 2:34 am    Post subject: Re: Sourcecode 2D-FFT Quote: I wrote a complex FFT routine that can also be used for 2D: http://www.simdesign.nl/fft.html Quite interesting. I once wrote an FFT for sound wave data, but it only works for dimensions which are a power of two (for sound processing this usually is ok). I just try to understand what's required for other dimensions... :-) -- Jens Gruschel http://www.pegtop.net Back to top Nils Haeck Guest Posted: Tue Nov 14, 2006 3:31 am    Post subject: Re: Sourcecode 2D-FFT Quote: Quite interesting. I once wrote an FFT for sound wave data, but it only works for dimensions which are a power of two (for sound processing this usually is ok). I just try to understand what's required for other dimensions... Are you confusing dimensions and data set size? Sound is usally 1D. But with mixed-radix FFT you can do data set sizes of e.g. 10000 instead of 1024. It works because it splits up the data set into it's factors, and has "optimized" code for the lower factors, e.g. 10000 would be split up in 10 * 10 * 10 * 10. Each factor 10 is then split up in 2 * 5. Etc. The shit hits the fan though if you try to do series with lengths of e.g. 1023, or any large prime, since it can't be split up into factors, and thus it resorts to a very lengthy operation of the standard discrete fourier transform. Btw, the complex FFT can help for sound, because in complex 1D FFT you transform a real and imaginary part of a complex number. You can fill the left channel in the real part, the right channel in the imag part, and then for the price of 1 you can do stereo FFT :) Nils Back to top Jens Gruschel Guest Posted: Tue Nov 14, 2006 3:53 am    Post subject: Re: Sourcecode 2D-FFT Quote: Are you confusing dimensions and data set size? Yes :-) Quote: The shit hits the fan though if you try to do series with lengths of e.g. 1023, or any large prime, since it can't be split up into factors, and thus it resorts to a very lengthy operation of the standard discrete fourier transform. I see. Quote: Btw, the complex FFT can help for sound, because in complex 1D FFT you transform a real and imaginary part of a complex number. You can fill the left channel in the real part, the right channel in the imag part, and then for the price of 1 you can do stereo FFT Very neat idea. I'll add that to my class (and post it here if anyone is interested). However I have one more question: the result of such a "stereo FFT" cannot be separated again, it's the combined result of both channels, or am I wrong? -- Jens Gruschel http://www.pegtop.net Back to top Nils Haeck Guest Posted: Tue Nov 14, 2006 4:25 am    Post subject: Re: Sourcecode 2D-FFT Quote: Very neat idea. I'll add that to my class (and post it here if anyone is interested). However I have one more question: the result of such a "stereo FFT" cannot be separated again, it's the combined result of both channels, or am I wrong? No, it *can* be separated, otherwise what would it bring But.. don't ask me how. You can find very good info in the book "Scientists and engineers guide to digital signal processing", with example code. You can download all relevant chapters as PDF for free. http://www.dspguide.com/pdfbook.htm Kind regards, Nils Back to top Jens Gruschel Guest Posted: Tue Nov 14, 2006 4:33 am    Post subject: Re: Sourcecode 2D-FFT Quote: No, it *can* be separated, otherwise what would it bring But.. don't ask me how. Well, I'll try that later. For now I don't need it, since I only required it for some simple spectrum analyzis (for example for my Smoodoo screensaver to detect the beat). Now I realize that my unit is not that flexible. However I posted the current version to b.p.attachments (wave spectrum analyzer). Quote: You can find very good info in the book "Scientists and engineers guide to digital signal processing", with example code. You can download all relevant chapters as PDF for free. http://www.dspguide.com/pdfbook.htm Yes, I already looked at it (and added the book to my Amazon wish list). Seems like I have to look at it again... -- Jens Gruschel http://www.pegtop.net Back to top John Herbster Guest Posted: Tue Nov 14, 2006 6:32 am    Post subject: Re: Sourcecode 2D-FFT "Nils Haeck" <bla (AT) bla (DOT) com> wrote Quote: ... But with mixed-radix FFT you can do data set sizes of e.g. 10000 instead of 1024. It works because it splits up the data set into it's factors, and has "optimized" code for the lower factors, e.g. 10000 would be split up in 10 * 10 * 10 * 10. Each factor 10 is then split up in 2 * 5. Etc. I call that a Glassman FFT, after one for the guys who first came up with the idea or the code. http://www.google.com/search?hl=en&q=Glassman+FFT --JohnH Back to top Nils Haeck Guest Posted: Tue Nov 14, 2006 8:13 am    Post subject: Re: Sourcecode 2D-FFT Quote: I call that a Glassman FFT, after one for the guys who first came up with the idea or the code. http://www.google.com/search?hl=en&q=Glassman+FFT --JohnH Exactly, I did indeed use old Fortran files I found in some library and translated them to Delphi, probably the ones mentioned in the link I put in some optimizations for 2x5=10 and 2x8=4x4 which I found somewhere else. It's probably not yet most optimized as it could be, this one would benefit a lot from SSE, unrolling and such. Nils Back to top Nils Haeck Guest Posted: Tue Nov 14, 2006 8:22 am    Post subject: Re: Sourcecode 2D-FFT Actually I looked it up and I used the one by Singleton, 1968: http://faculty.prairiestate.edu/skifowit/fft/fft2.txt In fact that is *earlier* than Glassmann wrote his article (1970's).. interesting :) This page contains more algorithm links: http://faculty.prairiestate.edu/skifowit/fft Nils Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         BorlandTalk.com Forum Index -> Delphi Graphics All times are GMT Goto page 1, 2  Next Page 1 of 2   Jump to: Select a forum C++ Builder Newsgroups----------------C++ BuilderC++ Builder (ActiveX)C++ Builder (Announcements)C++ Builder (Command Line Tools)C++ Builder DatabasesC++ Builder Databases (ADO)C++ Builder Databases (Desktop)C++ Builder Databases (InterBase Express)C++ Builder Databases (Multi-Tier)C++ Builder Databases (SQL Servers)C++ Builder (Graphics)C++ Builder (IDE)C++ Builder (Internet)C++ Builder (Internet Socket)C++ Builder (Internet Web)C++ Builder (Jobs)C++ Builder (Language)C++ Builder (Language C++)C++ Builder (Compatibility with MFC)C++ Builder (Native API)C++ Builder (Non-Technical)C++ Builder (Students)C++ Builder (Third Party Tools)C++ Builder (Upgrade)C++ Builder (VCL)C++ Builder (VCL Components Usage)C++ Builder (VCL Components Development)C++ Builder (VCL Usage)C++ Builder (WinAPI)C++ Builder Installation Delphi Newsgroups----------------Delphi (General)Delphi ActiveX Controls UsageDelphi ActiveX Controls DevelopmentDelphi As400Delphi DatabasesDelphi Databases (ADO)Delphi Databases (dbExpress)Delphi Databases (Desktop)Delphi Databases (InterBase Express)Delphi Databases (Multi-Tier)Delphi Databases (SQL Servers)Delphi DeploymentDelphi GraphicsDelphi IDEDelphi InternationalizationDelphi InternetDelphi Internet Isapi-WebBrokerDelphi Internet WebSnapDelphi Internet WinsockDelphi JobsDelphi Language BASMDelphi Language ObjectPascalDelphi Model Driven Architecture (General)Delphi Model Driven Architecture (Third Party)Delphi MultimediaDelphi Native APIDelphi Non-TechnicalDelphi ObjectPascalDelphi OLE AutomationDelphi OO designDelphi OpenToolsAPIDelphi Reporting-ChartingDelphi RTLDelphi StudentsDelphi TeamSourceDelphi Thirdparty ToolsDelphi Thirdparty Tools (General)Delphi Thirdparty Tools (IntraWeb)Delphi Thirdparty Tools (RaveReports)Delphi UpgradeDelphi VCLDelphi VCL ComponentsDelphi VCL Components UsingDelphi VCL Components WritingDelphi WebServices SOAPDelphi WinAPIDelphi XMLDelphi Installationcomp.lang.pascal.delphi.components.misccomp.lang.pascal.delphi.components.usagecomp.lang.pascal.delphi.components.writingcomp.lang.pascal.delphi.databasescomp.lang.pascal.delphi.misccomp.sources.delphi JBuilder Newsgroups----------------JBuilderJBuilder AnnouncementsJBuilder Applet IssuesJBuilder As400JBuilder CompilerJBuilder CORBA/RMIJBuilder DatabasesJBuilder DB SwingJBuilder DebuggerJBuilder DeploymentJBuilder DocumentationJBuilder EnterpriseJBuilder HandheldJBuilder IDEJBuilder JavaJBuilder JavaAPIJBuilder Java LanguageJBuilder Java SwingJBuilder Java BeansJBuilder Java Beans UsageJBuilder Java Beans DevelopmentJBuilder JBCLJBuilder JDataStoreJBuilder JobsJBuilder LinuxJBuilder MacintoshJBuilder & MobileSetJBuilder MultiLingual AppsJBuilder Non-TechnicalJBuilder OpenToolsJBuilder Servlets (JSP)JBuilder StudentsJBuilder Team DevelopmentJBuilder Thirdparty ToolsJBuilder UpgradeJBuilder Installation InterBase Newsgroups----------------InterBaseInterBase Bug DiscussionInterBase GeneralInterBase IBConsoleInterBase OpenSourceInterBase ReplicationInterBase SQLInterBase ThirdpartyInterBase Installation Miscellaneous Borland Newsgroups----------------AppCenterAppServerEnteraVisiBroker  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.