Question

我使用Eigen库将几个itk :: image图像转换为矩阵，并对它们进行一些密集的线性代数计算。最后，我将输出作为矩阵，但我需要它以itk :: image形式。有没有办法做到这一点？

    const unsigned int numberOfPixels = importSize[0] * importSize[1];
    float* array1 = inverseU.data();
    float* localBuffer = new float[numberOfPixels];
    std::memcpy(localBuffer, array1, numberOfPixels);
    const bool importImageFilterWillOwnTheBuffer = true;
    importFilter->SetImportPointer(localBuffer,numberOfPixels,importImageFilterWillOwnTheBuffer);
    importFilter->Update();

inverseU是特征库矩阵（float），importSize是此矩阵的大小。当我提供importFilter-＆gt; GetOutput（）并将结果写入文件时，我得到的图像就像this，这是不正确的。

这是矩阵inverseU。 https://drive.google.com/file/d/0B3L9EtRhN11QME16SGtfSDJzSWs/view?usp=sharing。它应该以图像形式给出视网膜眼底图像，我在进行去模糊后得到了矩阵。

Answer 1

看看itk的ImportImageFilter。特别是，它可以用于从C样式数组（example）开始构建itk::Image。

最近有人问how to convert a CImg image to ITK image。我的回答可能是一个起点...

可以找到一种从Eigen中取出矩阵A的方法here：

double* array=A.data();

编辑：这是一段代码，用于将浮动矩阵转换为使用ITK保存的png图像。首先，矩阵转换为浮动图像。然后，使用解释here的RescaleIntensityImageFilter将此图像重新调整为无符号字符的图像。最后，图像以png格式保存。

#include <iostream>
#include <itkImage.h>

using namespace itk;
using namespace std;

#include <Eigen/Dense>
using Eigen::MatrixXf;

#include <itkImportImageFilter.h>
#include <itkImageFileWriter.h>
#include "itkRescaleIntensityImageFilter.h"

void eigen_To_ITK (MatrixXf mat)
{

    const unsigned int Dimension = 2;

    typedef itk::Image<unsigned char, Dimension>  UCharImageType;
    typedef itk::Image< float, Dimension > FloatImageType;
    typedef itk::ImportImageFilter< float, Dimension > ImportFilterType;
    ImportFilterType::Pointer importFilter = ImportFilterType::New();

    typedef itk::RescaleIntensityImageFilter< FloatImageType, UCharImageType > RescaleFilterType;
    RescaleFilterType::Pointer rescaleFilter = RescaleFilterType::New();

    typedef itk::ImageFileWriter<  UCharImageType  > WriterType;
    WriterType::Pointer writer = WriterType::New();


    FloatImageType::SizeType imsize;
    imsize[0] = mat.rows();
    imsize[1] = mat.cols();

    ImportFilterType::IndexType start;
    start.Fill( 0 );
    ImportFilterType::RegionType region;
    region.SetIndex( start );
    region.SetSize( imsize );
    importFilter->SetRegion( region );

    const itk::SpacePrecisionType origin[ Dimension ] = { 0.0, 0.0 };
    importFilter->SetOrigin( origin );

    const itk::SpacePrecisionType spacing[ Dimension ] = { 1.0, 1.0 };
    importFilter->SetSpacing( spacing );

    const unsigned int numberOfPixels = imsize[0] * imsize[1];

    const bool importImageFilterWillOwnTheBuffer = true;

    float * localBuffer = new float[ numberOfPixels ];
    float * it = localBuffer;

    memcpy(it, mat.data(), numberOfPixels*sizeof(float));
    importFilter->SetImportPointer( localBuffer, numberOfPixels,importImageFilterWillOwnTheBuffer );

    rescaleFilter ->SetInput(importFilter->GetOutput());
    rescaleFilter->SetOutputMinimum(0);
    rescaleFilter->SetOutputMaximum(255);


    writer->SetFileName( "output.png" );
    writer->SetInput(rescaleFilter->GetOutput() );
    writer->Update();

}

int main()
{

    const int rows = 42;
    const int cols = 90;
    MatrixXf mat1(rows, cols);
    mat1.topLeftCorner(rows/2, cols/2) = MatrixXf::Zero(rows/2, cols/2);
    mat1.topRightCorner(rows/2, cols/2) = MatrixXf::Identity(rows/2, cols/2);
    mat1.bottomLeftCorner(rows/2, cols/2) = -MatrixXf::Identity(rows/2, cols/2);
    mat1.bottomRightCorner(rows/2, cols/2) = MatrixXf::Zero(rows/2, cols/2);

    mat1+=0.1*MatrixXf::Random(rows,cols);

    eigen_To_ITK (mat1);

    cout<<"running fine"<<endl;
    return 0;
}

该程序使用CMake构建。这是CMakeLists.txt：

cmake_minimum_required(VERSION 2.8 FATAL_ERROR)
project(ItkTest)

find_package(ITK REQUIRED)
include(${ITK_USE_FILE})

# to include eigen. This path may need to be changed
include_directories(/usr/local/include/eigen3)

add_executable(MyTest main.cpp)
target_link_libraries(MyTest ${ITK_LIBRARIES})

有没有办法将Eigen :: Matrix转换回itk :: image？

1 个答案: