It seems that setting ITK_USE_SYSTEM_FFTW=ON is not enough to enable fftw support in ITK. You also should add ITK_USE_FFTWD=ON and ITK_USE_FFTWF=ON to enable the desired fftw flavour (for double and float). Please consider adding these two configuration options in a next build, so ITK can use system-wide fftw: [bellet@bonobo x]$ ldd usr/lib64/lib* | grep -i fft libITKFFT-4.7.so.1 => not found libfftw3.so.3 => /lib64/libfftw3.so.3 (0x00007f6db0dc5000) libfftw3_threads.so.3 => /lib64/libfftw3_threads.so.3 (0x00007f6db0bbe000) libfftw3f.so.3 => /lib64/libfftw3f.so.3 (0x00007f6db07b1000) libfftw3f_threads.so.3 => /lib64/libfftw3f_threads.so.3 (0x00007f6db05aa000) usr/lib64/libITKFFT-4.7.so.1: libfftw3.so.3 => /lib64/libfftw3.so.3 (0x00007f97a154b000) libfftw3_threads.so.3 => /lib64/libfftw3_threads.so.3 (0x00007f97a1344000) libfftw3f.so.3 => /lib64/libfftw3f.so.3 (0x00007f97a0f37000) libfftw3f_threads.so.3 => /lib64/libfftw3f_threads.so.3 (0x00007f97a0d30000) libITKFFT-4.7.so.1 => not found libfftw3.so.3 => /lib64/libfftw3.so.3 (0x00007f9d8833f000) libfftw3_threads.so.3 => /lib64/libfftw3_threads.so.3 (0x00007f9d88138000) libfftw3f.so.3 => /lib64/libfftw3f.so.3 (0x00007f9d87d2b000) libfftw3f_threads.so.3 => /lib64/libfftw3f_threads.so.3 (0x00007f9d87b24000)
InsightToolkit-4.7.2-2.fc22 has been submitted as an update for Fedora 22. https://admin.fedoraproject.org/updates/InsightToolkit-4.7.2-2.fc22
Package InsightToolkit-4.7.2-2.fc22: * should fix your issue, * was pushed to the Fedora 22 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing InsightToolkit-4.7.2-2.fc22' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2015-11213/InsightToolkit-4.7.2-2.fc22 then log in and leave karma (feedback).
InsightToolkit-4.7.2-2.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.