ITK  5.3.0
Insight Toolkit
Examples/Statistics/MembershipSampleGenerator.cxx
/*=========================================================================
*
* Copyright NumFOCUS
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
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*=========================================================================*/
// Software Guide : BeginLatex
//
// \index{itk::Statistics::List\-Sample\-To\-Histogram\-Filter}
// \index{itk::Statistics::List\-Sample\-To\-Histogram\-Generator}
// \index{itk::Statistics::Neighborhood\-Sampler}
// \index{itk::Statistics::Sample\-To\-Histogram\-Projection\-Filter}
// \index{itk::Statistics::Selective\-Subsample\-Generator}
// \index{itk::Statistics::Membership\-Sample\-Generator}
//
// To use, an \code{MembershipSample} object, we include the header files for
// the class itself and a \code{Sample} class. We will use the
// \code{ListSample} as the input sample.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
#include "itkListSample.h"
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// We need another header for measurement vectors. We are going to use
// the \doxygen{Vector} class which is a subclass of the \doxygen{FixedArray}
// in this example.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
#include "itkVector.h"
// Software Guide : EndCodeSnippet
int
main()
{
// Software Guide : BeginLatex
//
// The following code snippet will create a \code{ListSample} object
// with three-component float measurement vectors and put three
// measurement vectors in the \code{ListSample} object.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using MeasurementVectorType = itk::Vector<float, 3>;
SampleType::Pointer sample = SampleType::New();
MeasurementVectorType mv;
mv[0] = 1.0;
mv[1] = 2.0;
mv[2] = 4.0;
sample->PushBack(mv);
mv[0] = 2.0;
mv[1] = 4.0;
mv[2] = 5.0;
sample->PushBack(mv);
mv[0] = 3.0;
mv[1] = 8.0;
mv[2] = 6.0;
sample->PushBack(mv);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// To create a \code{MembershipSample} instance, we define the type of the
// \code{MembershipSample} with the source sample type, in this case,
// previously defined \code{SampleType}. As usual, after that, we call
// \code{New()} method to instantiate an instance. We must plug in the
// source sample, \code{sample} object using the
// \code{SetSample(source sample)} method. However, in regard to
// \textbf{class labels}, the \code{membershipSample} is empty. We
// provide class labels for data instances in the \code{sample} object
// using the \code{AddInstance(class label, instance identifier)}
// method. As the required initialization step for the
// \code{membershipSample}, we must call the
// \code{SetNumberOfClasses(number of classes)} method with the number
// of classes. We must add all instances in the source sample with
// their class labels. In the following code snippet, we set the first
// instance class label to 0, the second to 0, the third (last) to
// 1. After this, the \code{membershipSample} has two \code{Subclass}
// objects. And the class labels for these two \code{Subclass} are 0
// and 1. The \textbf{0} class \code{Subsample} object includes the
// first and second instances, and the \textbf{1} class includes the
// third instance.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using MembershipSampleType = itk::Statistics::MembershipSample<SampleType>;
MembershipSampleType::Pointer membershipSample =
MembershipSampleType::New();
membershipSample->SetSample(sample);
membershipSample->SetNumberOfClasses(2);
membershipSample->AddInstance(0U, 0UL);
membershipSample->AddInstance(0U, 1UL);
membershipSample->AddInstance(1U, 2UL);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The \code{Size()} and \code{GetTotalFrequency()} methods return the same
// values as the \code{sample}.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
std::cout << "Size = " << membershipSample->Size() << std::endl;
std::cout << "Total frequency = " << membershipSample->GetTotalFrequency()
<< std::endl;
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The \code{membershipSample} is ready for use. The following code snippet
// shows how to use \code{Iterator} interfaces. The
// \code{MembershipSample} \code{Iterator} has an additional method
// that returns the class label (\code{GetClassLabel()}).
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
MembershipSampleType::Iterator iter = membershipSample->Begin();
while (iter != membershipSample->End())
{
std::cout << "instance identifier = " << iter.GetInstanceIdentifier()
<< "\t measurement vector = " << iter.GetMeasurementVector()
<< "\t frequency = " << iter.GetFrequency()
<< "\t class label = " << iter.GetClassLabel() << std::endl;
++iter;
}
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// To see the numbers of instances in each class subsample, we use
// the \code{GetClassSampleSize(class label)} method.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
std::cout << "class label = 0 sample size = "
<< membershipSample->GetClassSampleSize(0) << std::endl;
std::cout << "class label = 1 sample size = "
<< membershipSample->GetClassSampleSize(0) << std::endl;
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// We call the \code{GetClassSample(class label)} method to get the
// class subsample in the \code{membershipSample}. The
// \code{MembershipSampleType::ClassSampleType} is actually an
// specialization of the \subdoxygen{Statistics}{Subsample}. We print
// out the instance identifiers, measurement vectors, and frequency
// values that are part of the class. The output will be two lines for
// the two instances that belong to the class \textbf{0}.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
MembershipSampleType::ClassSampleType::Pointer classSample =
membershipSample->GetClassSample(0);
MembershipSampleType::ClassSampleType::Iterator c_iter =
classSample->Begin();
while (c_iter != classSample->End())
{
std::cout << "instance identifier = " << c_iter.GetInstanceIdentifier()
<< "\t measurement vector = " << c_iter.GetMeasurementVector()
<< "\t frequency = " << c_iter.GetFrequency() << std::endl;
++c_iter;
}
// Software Guide : EndCodeSnippet
return EXIT_SUCCESS;
}
itk::Statistics::MembershipSample
Container for storing the instance-identifiers of other sample with their associated class labels.
Definition: itkMembershipSample.h:57
itk::Vector
A templated class holding a n-Dimensional vector.
Definition: itkVector.h:62
itk::Statistics::ListSample
This class is the native implementation of the a Sample with an STL container.
Definition: itkListSample.h:51
itkMembershipSample.h
itkListSample.h
itkVector.h