function H = computeH(U,controlPoints,h,iCP,Cval)

% Subfunction of the Simulated Annealing program.
% Calculates the local energy function associated with a particular
% value of a given control point.


% Initialize auxiliary variables
nOrder = 3;
nControlPoints = length(controlPoints);
nCBegin = max(1,iCP - nOrder);
nCEnd = min(iCP + nOrder, nControlPoints);

% Assemble set of control point affected by change.
newControlPoints = [ controlPoints(nCBegin:(iCP - 1));
                     Cval;
                     controlPoints((iCP + 1):nCEnd) ];

% Calculate splines section from control points
newContour = formBspline(newControlPoints,h);
L = length(newContour);

% Calculate potential energy
H0 = 0;
[nx, ny] = size(U);
for i = 1:L,
    H0 = H0 + U(max(1,min(nx,round(newContour(i)))), (nCBegin-1) * h + i);
end

% Calculate energy for slope
H1 = sum(conv(newContour,[-1 2 -1]).^2);

% Calculate overall energy
H = H0 + .00015 * H1;