CardiacMRI:
- Last thing I was dealing with was temporal fft operator that I have put in opFFTxd.m in util directory.
- Problem setup is now kind of realistic:
    - user choose upload cardiac images from dataset
    - he can shose the slice number (1-10 - default is 5)
    - sigma level (0.05 by default)
    - undersampling factor (fold  default is 6)
    - n image size (256 by default)
    - read 3d matrix of n*n cardiac images in szt time points
    - adds noise sigma*var(signal)
    - do 2d circular fft per image and take random lines as specified by mask
    - mask is made to sample n*szt/fold lines in phase encode and time dimensions
    - play movies of original, undersampled cardiac images and mask