ScalarConnectedComponentImageFilter 连通区域

手动创建一个黑色0的图片，其中加入两个矩形，一个为像素值为100的灰色；另一个是像素值为255的白色

将图片输出为png和TXT

用连通区域算子计算出连通区域1，2，3

将连通区域输出到TXT

为了能够显示像素为1，2，3的图片，放大这些像素

输出放大后的像素图片到png

输出放大后的像素图片到TXT

#include "itkImage.h"
#include <vtkSmartPointer.h>
#include <vtkPNGWriter.h>
#include "itkScalarConnectedComponentImageFilter.h"
#include <itkImageToVTKImageFilter.h> 
#include <itkVTKImageToImageFilter.h>
#include <string>
#include <iostream>
#include<vtkImageShiftScale.h>

void CreateImage(itk::Image<unsigned char, 2>* const image)
{
	// Create an image with 2 connected components
	itk::Image<unsigned char, 2>::IndexType start = { {0,0} };
	start[0] = 0;
	start[1] = 0;

	itk::Image<unsigned char, 2>::SizeType size;
	unsigned int NumRows = 100;
	unsigned int NumCols = 200;
	size[0] = NumRows;
	size[1] = NumCols;

	typename itk::Image<unsigned char, 2>::RegionType region(start, size);

	image->SetRegions(region);
	
	image->Allocate(true);// 全0的像素（黑色）

	// Make a square
	for (itk::Image<unsigned char, 2>::IndexValueType r = 5; r < 40; r++)
	{
		for (itk::Image<unsigned char, 2>::IndexValueType c = 10; c < 50; c++)
		{
			itk::Image<unsigned char, 2>::IndexType pixelIndex = { {r,c} };

			image->SetPixel(pixelIndex, 100);//灰色
		}
	}

	// Make another square
	for (typename itk::Image<unsigned char, 2>::IndexValueType r = 50; r < 70; r++)
	{
		for (typename itk::Image<unsigned char, 2>::IndexValueType c = 50; c < 80; c++)
		{
			typename itk::Image<unsigned char, 2>::IndexType pixelIndex = { {r,c} };

			image->SetPixel(pixelIndex, 255);//白色
		}
	}

}
void print(const std::string& file, itk::Image<unsigned char, 2>* image)
{
	ofstream fout(file);
	auto size = image->GetBufferedRegion().GetSize();
	for (auto i = 0; i < size[0]; i++)
	{
		for (auto j = 0; j < size[1]; j++)
		{
			itk::Image<unsigned char, 2>::IndexType index{ {i,j} };
			auto c = image->GetPixel(index);
			fout << (int)c;
		}
		fout << std::endl;
	}
}
int main(int argc, char *argv[])
{
	short distanceThreshold = 4;

	auto image = itk::Image<unsigned char, 2>::New();
	CreateImage(image.GetPointer());// 创建一个背景为黑色的，包含两个长方形区域（一个为灰色100，一个为白色255）的图片
	image->Update();

	//将itk图片转换成vtk图片
	auto imageToVtkImage = itk::ImageToVTKImageFilter<itk::Image<unsigned char, 2>>::New();
	imageToVtkImage->SetInput(image.GetPointer());
	imageToVtkImage->Update();// 只有更新之后，后续使用者才可以拿到真正的数据

	//保存vtk图片为png文件
	vtkSmartPointer<vtkPNGWriter> writer = vtkSmartPointer<vtkPNGWriter>::New();
	writer->SetFileName("E:/1/1CreateImage.png");
	writer->SetInputData(imageToVtkImage->GetOutput());
	writer->Write();
	//保存vtk图片像素值到文本文件
	print("E:/1/1CreateImage.txt", image.GetPointer());

	//从vtk图片得到连通区域:1,2,3(每个连通区域中的像素点的值)
	auto connected = itk::ScalarConnectedComponentImageFilter<itk::Image<unsigned char, 2>, itk::Image<unsigned char, 2>>::New();
	connected->SetInput(image);
	connected->SetDistanceThreshold(distanceThreshold);
	connected->Update();
	//输出vtk图片连通区域:1,2,3
	print("E:/1/2ScalarConnectedComponentImage.txt", connected->GetOutput());

	//连通区域图片的像素值为label值，只有1,2,3。
	//每个连通区域的像素都用一个Id值存储，由于1,2,3这种值作为像素值的话都是接近黑色，
	//所以要想打印出区分明显的图片需要vtkImageShiftScale变换
	imageToVtkImage->SetInput(connected->GetOutput());
	imageToVtkImage->Update();

	double range[2];
	imageToVtkImage->GetOutput()->GetScalarRange(range);

	vtkSmartPointer<vtkImageShiftScale>scale = vtkSmartPointer<vtkImageShiftScale>::New();
	scale->SetInputData(imageToVtkImage->GetOutput());
	scale->SetScale(255 / range[1]);//大范围的最大值除以小范围的最大值得到变换的放大倍数：(1，2, 3)->(85, 170, 255)
	scale->Update();

	//将变换后的图片保存到png
	writer->SetFileName("E:/1/3ConnectedComponentImage.png");
	writer->SetInputData(scale->GetOutput());
	writer->Write();

	auto vtkImageToImage = itk::VTKImageToImageFilter<itk::Image<unsigned char, 2>>::New();
	vtkImageToImage->SetInput(scale->GetOutput());
	vtkImageToImage->Update();
	//输出连通区域：(85, 170, 255)
	print("E:/1/3ConnectedComponentImage.txt", vtkImageToImage->GetOutput());

	std::cout << "return ok" << std::endl;

	return EXIT_SUCCESS;
}

1CreateImage.png

1CreateImage.txt

2ScalarConnectedComponentImage.txt

3ConnectedComponentImage.png

3ConnectedComponentImage.txt