particle swarm optimizer

Algorithms
1

Hello everyone,
I was wondering if itk developers provided a registration example between two 3d images using particle swarm optimizer ? Thank you

2

I don’t think there is such an example, but you can be inspired by particle swarm’s unit test and a registration example of your choice (perhaps this one).

3

ok, thank you @dzenanz

4

I tried your solution @dzenanz and when I execute my program it stops just before finishing the registration process with this error message: Description: itk::ERROR: ParticleSwarmOptimizer(0x5578e8497ac0): cost function and parameter bounds dimensions mismatch
My question is: how can I declare a cost function?

5

okay, I managed to understand where the error came from. Just another question: what is OptimizerType::ParameterBoundsType bounds;?
If I use 3d euler coordinates system, do I have to initialize bounds like this: itk_pso_bounds ?
Where the first three pushbacks bounds euler angles and the three last pushbacks bounds the translation among x, y, and z?

6

Use your IDE to explore the exact definition of this type.

You initialization with 6 pairs of values is good in principle, but I don’t know whether it compiles.

7

again and again, thank you @dzenanz, my program works fine now

8

Maybe explain what was the exact problem and solution, in case somebody comes across this thread in the future?

9

excuse me for the late reply. My problem was in fact very basic: I had a segfault when launching my registration program which uses a particle swarm optimizer. I just had to declare ParameterBoundsType and push_back() some double values in it.
The first three push_back() concerns Euler rotation bounds, the three last translation bounds.
Here is a sample of code which compiles and runs:

const uint16_t MAXIMUM_NUMBER_OF_ITERATIONS = 100;
const uint16_t RANDOM_SEED = 50;
const bool SEED = true;
const double GLOBAL_COEFFICIENT = 1.1;
const double INERTIA_COEFFICIENT = 0.6;
const double PERSONAL_COEFFICIENT = 1.1;
const double NUMBER_OF_GENERATION_WITH_MINIMAL_IMPROVMENT = 10;
const double NUMBER_OF_PARTICLES = 100;
const double PERCENTAGE_PARTICLES_CONVERGED = 15;
const double X_TOLERANCE = 0.01;
const double F_TOLERENCE = 0.01;
const bool INITIALIZE_WITH_NORMAL_DISTRIBUTION = true;
const double EULER_ANGLES_BOUNDS = 0.1; // in degrees
const double XYZ_TRANSLATION_BOUNDS = 0.1; // in mm
const double ROTATION_TRANSLATION_OPTIMIZER_VALUE = 1; // divids rotation and translation parametric space by this value

optimizer->SetGlobalCoefficient( GLOBAL_COEFFICIENT );
optimizer->SetInertiaCoefficient( INERTIA_COEFFICIENT );
optimizer->SetPersonalCoefficient( PERSONAL_COEFFICIENT );
optimizer->SetMaximalNumberOfIterations( MAXIMUM_NUMBER_OF_ITERATIONS );
optimizer->SetNumberOfGenerationsWithMinimalImprovement( NUMBER_OF_GENERATION_WITH_MINIMAL_IMPROVMENT );
optimizer->SetNumberOfParticles( NUMBER_OF_PARTICLES );
optimizer->SetPercentageParticlesConverged( PERCENTAGE_PARTICLES_CONVERGED );
optimizer->SetSeed( RANDOM_SEED );
optimizer->SetUseSeed( SEED );
optimizer->SetParametersConvergenceTolerance( X_TOLERANCE, NUMBER_OF_PARAMETERS );
optimizer->SetFunctionConvergenceTolerance( F_TOLERENCE );
optimizer->SetInitializeNormalDistribution( INITIALIZE_WITH_NORMAL_DISTRIBUTION );

ParametersType alignment_parameters = transform->GetParameters();
alignment_parameters.Fill( 0 );
optimizer->SetInitialPosition( alignment_parameters );

OptimizerType::ParameterBoundsType bounds;
bounds.push_back( std::make_pair( - EULER_ANGLES_BOUNDS, EULER_ANGLES_BOUNDS ) );
bounds.push_back( std::make_pair( - EULER_ANGLES_BOUNDS, EULER_ANGLES_BOUNDS ) );
bounds.push_back( std::make_pair( - EULER_ANGLES_BOUNDS, EULER_ANGLES_BOUNDS ) );
bounds.push_back( std::make_pair( - XYZ_TRANSLATION_BOUNDS, XYZ_TRANSLATION_BOUNDS ) );
bounds.push_back( std::make_pair( - XYZ_TRANSLATION_BOUNDS, XYZ_TRANSLATION_BOUNDS ) );
bounds.push_back( std::make_pair( - XYZ_TRANSLATION_BOUNDS, XYZ_TRANSLATION_BOUNDS ) );
optimizer->SetParameterBounds( bounds );
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