This function implements the Fourier Shape Descriptors for single-connected-component binary region. Users can tune the ratio of boundary pixels to the number of Fourier coefficients, with an aim to see how original region boundary degenerates into a circle. Often we can see the ratio go up to around 10~50 and preserve the boundary reasonably well. A sample binary spike ball image is included for demo convenience. Students can use this package as a tutorial to grasp the concepts of Fourier Shape Descriptors.