The implementation in this assignment focuses on a relaxation method described by Horn in section 11.7

in [3]. The technique minimizes a smoothness energy function and which is the energy function for

the image irradiance. The two functions are combined with

, where is a parameter that weights

the errors. With use of variational calculus, a solution is expressed in terms of differential equations. A

solution can also be obtained by minimizing the discretised energy functions. This approach was chosen for

the assignment since it is written out explicitly in the book.