Download or view FourierImageTest.frink in plain text format
/** This demonstrates using Fourier transforms to process an image, obtain its
Fourier transform, display the Fourier transform in a logarithmic scale,
and then invert the transform to produce the original image.
This file is similar to the FourierImage.frink file but contains more stuff
for debugging Fourier Transforms, the log magnitude/phase plots, etc.
*/
//img = new image["file:kittyface.jpg"]
//img = new image["file:../docs/images/futureboylogo512x512.png"]
img = new image["file:AudreyHepburnMoire.jpg"]
//img = new image["file:../docs/images/futureboylogo114x114.png"]
//img = new image["file:../fawncircles.jpg"]
img = img.resize[1024, undef]
//img = new image[4096,4096]
//img.makeARGB[]
[origWidth, origHeight] = img.getSize[]
println["image size is [$origWidth, $origHeight]"]
array = img.toComplexArray[]
println["\narray is " + first[array@0, 5]]
/*
start = now[]
df = DFT[array]
end = now[]
println["Time in DFT: " + (end-start -> "ms")]
*/
start = now[]
ff = FFT[array]
end = now[]
println["Time in FFT: " + (end-start -> "ms")]
// If the flag below is true, this assumes the DC component is in the
// center of the image. This needs to match the value in the
// .toComplexArrayFromLog call below.
img2f = ff.toLogImage[true]
println["Resultant image size from FFT is " + img2f.getSize[]]
img2f.show[]
img2f.write["fft.png"]
/*
img2d = df.toLogImage[]
println["Resultant image size from DFT is " + img2d.getSize[]]
img2d.show[]
*/
start = now[]
inverseF = inverseFFT[ff]
end = now[]
println["Time in inverseFFT: " + (end-start -> "ms")]
inverseImgF = inverseF.toImage[origWidth, origHeight]
//inverseImgF = inverseF.toImage[]
println["Resultant image size from inverse FFT is " + inverseImgF.getSize[]]
//inverseImgF.show[]
inverseImgF.write["reconstructed.png"]
/*
inverseD = inverseDFT[df]
inverseImgD = inverseD.toImage[]
println["Resultant image size from inverse DFT is " + inverseImgD.getSize[]]
inverseImgD.show[]
*/
println["\nff is " + first[ff@0, 5]]
a2 = img2f.toComplexArrayFromLog[]
println["\na2 is " + first[a2@0, 5]]
ia = inverseFFT[a2]
println["\nia is " + first[ia@0, 5]]
back = ia.toImage[origWidth, origHeight]
//back.show[]
diff = array.subtract[ia]
println["minReal = " + diff.getMinReal[]]
println["maxReal = " + diff.getMaxReal[]]
println["minImag = " + diff.getMinImag[]]
println["maxImag = " + diff.getMaxImag[]]
i3 = new image["file:fft.png"]
// If the flag below is true, this assumes the DC component is in the
// center of the image. This needs to match the value in the .toLogImage call
// above.
a3 = i3.toComplexArrayFromLog[true]
inv3 = inverseFFT[a3]
i3out = inv3.toImage[origWidth, origHeight]
i3out.show[]
i3out.write["denoised.png"]
Download or view FourierImageTest.frink in plain text format
This is a program written in the programming language Frink.
For more information, view the Frink
Documentation or see More Sample Frink Programs.
Alan Eliasen was born 19967 days, 4 hours, 58 minutes ago.