e 3. Formulate the classical shape from shading problem using the variational approach assuming that depth values are available at an arbitrary number of points. Construct the functional to be optimized and then derive the Euler equation. Discretize the Euler equation and derive an iterative equation for estimating depth. State the assumptions you have made. e 3. Formulate the classical shape from shading problem using the variational approach assuming that depth values are available at an arbitrary number of points. Construct the functional to be optimized and then derive the Euler equation. Discretize the Euler equation and derive an iterative equation for estimating depth. State the assumptions you have made