Changes between Version 1 and Version 2 of Examples/Fft2dHighpass

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Timestamp:
05/07/10 08:08:49 (5 years ago)
Author:
benl (IP: 129.94.242.38)
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  • Examples/Fft2dHighpass

    v1 v2  
    11== fft2d-highpass == 
    22 
    3 Applies a highpass filter to a BMP image, using a Fast Fourier Transform. The first argument is the lower cutoff frequency. 
     3Applies a highpass to a BMP image. The first argument is the lower cutoff frequency. 
     4 
     5Each of the RGB channels is converted to the frequency domain, the lower frequencies are set to zero, then the channels are converted back to the image domain. 
    46 
    57{{{ 
     
    79}}} 
    810 
     11=== Code === 
     12 
     13The main algorithm is at http://code.haskell.org/repa/repa-stable/repa-algorithms/Data/Array/Repa/Algorithms/FFT.hs 
     14 
     15The wrapper is at http://code.haskell.org/repa/repa-stable/repa-examples/FFT/src/HighPass/Main.hs 
    916 
    1017=== Test Data === 
    11  
    12 `lena.bmp` is a standard test image. See [http://en.wikipedia.org/wiki/Lenna http://en.wikipedia.org/wiki/Lenna] 
     18[http://en.wikipedia.org/wiki/Lenna http://en.wikipedia.org/wiki/Lenna] is a standard test image. 
    1319 
    1420|| lena.bmp || lena-high2.bmp || 
     21|| [[Image(Examples/Fft2dHighpass:lena-thumb.jpg)]] || [[Image(WikiStart:lena-high2-thumb.jpg)]] ||  
     22|| [http://code.haskell.org/repa/wiki/images/lena.bmp full size] || [http://code.haskell.org/repa/wiki/images/lena-high2.bmp full size] || 
    1523 
     24=== Runtime === 
     25Compiled with GHC 6.13.20100309. 512x512 image. 
     26 
     27Running on a Intel i7 iMac.   
     28 
     29|| Threads || Time(s) ||  
     30|| 1  || 24.81 || 
     31|| 2 || 13.37 ||  
     32|| 3 || 10.4 ||  
     33|| 4 || 7.79 ||  
     34|| 5 || 8.24 || 
     35|| 6 || 7.25 || 
     36|| 7 || 6.87 ||  
     37|| 8 || 6.58 || 
     38 
     39