Below you can find a link to the MATLAB code that calculates the L2 isogeometric bitmap projection.
The code uses the isogeometric finite element method in which the bitmap is approximated by a linear combination of B-spline polynomials.

The code execution is also possible in the free Octave environment.
Download code or see Appendix 1.

We set the variables with the path to the input file in tif format
\( filename = 'C://Users/Maciej/Dropbox/bitmapa.tif' \)
then we give the number of mesh elements in the x and y directions \( nxx=4 \), \( nyy=4 \),
and the degrees of the B-spline function in these directions \( pxx=2 \), \( pyy=2 \).
Then we start the first procedure
\( bitmap\_fast(filename,nxx,pxx,nyy,pyy) \).
The code computes the isogeometric L2 projection of a bitmap and draws the projection in the open window.