MATLAB: How to use “fmincon”

fminconMATLABoptimization

Hi,
I'm trying to optimize the parameters of an image registration procedure between two 3D images using the "fmincon" function. The code is the following:
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function optimize_parameters1
lb = [eps, eps, 1+eps, 10];
ub = [10, 1, 10, 255];
x = fmincon(@opt, [0.5, 0.5, 1.1, 150], [], [], [], [], lb, ub);
keyboard;
function val = opt(InitialRadius, Epsilon, GrowthFactor, NumberOfHistogramBins)
load('images.mat');
optimizer = registration.optimizer.OnePlusOneEvolutionary;
optimizer.InitialRadius = InitialRadius;
optimizer.Epsilon = Epsilon;
optimizer.GrowthFactor = GrowthFactor;
optimizer.MaximumIterations = 50;
metric = registration.metric.MattesMutualInformation();
metric.NumberOfHistogramBins = round(NumberOfHistogramBins);
metric.UseAllPixels = 1;
aligned = imregister( ...
    T.img, imref3d(size(T.img)), ...
    S.img, imref3d(size(S.img)), ...
    'rigid', optimizer, metric, ...
    'DisplayOptimization', 0, ...
    'InitialTransformation', affine3d(eye(4)), ...
    'PyramidLevels', 3);
val = sum((double(aligned(:))-double(S.img(:))).^2) * prod(S.header.spacing);
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However, I keep getting this error:
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Error using registration.optimizer.OnePlusOneEvolutionary/set.InitialRadius (line 152)
Expected input to be a scalar.
Error in optimize_parameters1>opt (line 16)
optimizer.InitialRadius = InitialRadius;
Error in fmincon (line 534)
      initVals.f = feval(funfcn{3},X,varargin{:});
Error in optimize_parameters1 (line 6)
x = fmincon(@opt, [0.5, 0.5, 1.1, 150], [], [], [], [], lb, ub);
Caused by:
    Failure in initial user-supplied objective function evaluation. FMINCON cannot continue.
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What am I doing wrong?
Thanks in advance!
Tomer

Best Answer

x = fmincon(@(x) opt(x(1),x(2),x(3),x(4)), [0.5, 0.5, 1.1, 150], [], [], [], [], lb, ub);
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