I don't think this exactly what you want, but you might like it anyway. You draw and it breaks it down into the 2D fourier series, and you can control the numbe

I don't think this exactly what you want, but you might like it anyway. You draw and it breaks it down into the 2D fourier series, and you can control the number of fourier terms which essentially acts like a crude high pass filter: http://www.jezzamon.com/fourier/ http://www.jezzamon.com/fourier/