VTK_Learning_图像（融合）混合（Viewport&vtkImageBlend）

布满荆棘的人生 2023-06-28 08:57 4阅读 0赞

# 1.vtkImageBlend #

> 图像融合利用图像的alpha通道和不透明度来实现。VTK中vtkImageBlend实现图像的融合。
> 
> vtkImageBlend可以接收多个图像输入，输出为融合图像。输出图像的像素间隔、原点、范围（extent）以及像素组分个数与第一个图像一致。
> 
> 该类提供了两种融合模式，默认的融合方式是标准模式。
> 
> 第二种是混合模式（Compound），该模式下输出结果经过alpha/opacity不透明度的和做过归一化。另外还可以设置一个阈值，当alpha\*opacity小于等于该阈值时会忽略该像素。

# 2.代码 #

>     #include <vtkAutoInit.h>
>     VTK_MODULE_INIT(vtkRenderingOpenGL);
>      
>     #include <vtkSmartPointer.h>
>     #include <vtkJPEGReader.h>
>     //#include <vtkImageCast.h>
>     #include <vtkImageData.h>
>     #include <vtkImageCanvasSource2D.h>
>     #include <vtkImageBlend.h>
>     #include <vtkImageActor.h>
>     #include <vtkRenderer.h>
>     #include <vtkRenderWindow.h>
>     #include <vtkRenderWindowInteractor.h>
>     #include <vtkInteractorStyleImage.h>
>      
>     int main()
>     {
>     //数据管线
>     	vtkSmartPointer<vtkJPEGReader> reader =
>     		vtkSmartPointer<vtkJPEGReader>::New();
>     	reader->SetFileName("data/lena-gray.jpg");
>     	reader->Update();
>      
>     	vtkSmartPointer<vtkImageCanvasSource2D> source=
>     		vtkSmartPointer<vtkImageCanvasSource2D>::New();
>     	source->SetNumberOfScalarComponents(1);
>     	source->SetScalarTypeToUnsignedChar();
>     	source->SetExtent(0,512,0,512,0,0);
>     	source->SetDrawColor(0,0,0);
>     	source->FillBox(0,512,0,512);
>     	source->SetDrawColor(255,255,255);
>     	source->FillBox(100,400,100,400);
>     	source->Update();
>      
>     	vtkSmartPointer<vtkImageBlend> blend =
>     		vtkSmartPointer<vtkImageBlend>::New();
>     	blend->SetInputData(0,reader->GetOutput());
>     	blend->SetInputData(1,source->GetOutput());
>     	blend->SetOpacity(0,0.4);
>     	blend->SetOpacity(1,0.6);
>     	blend->Update();
>     	
>     //渲染引擎
>     	vtkSmartPointer<vtkImageActor> actor1 =
>     		vtkSmartPointer<vtkImageActor>::New();
>     	actor1->SetInputData(reader->GetOutput());
>      
>     	vtkSmartPointer<vtkImageActor> actor2 =
>     		vtkSmartPointer<vtkImageActor>::New();
>     	actor2->SetInputData(source->GetOutput());
>      
>     	vtkSmartPointer<vtkImageActor> blend_actor =
>     		vtkSmartPointer<vtkImageActor>::New();
>     	blend_actor->SetInputData(blend->GetOutput());
>     	//定义视窗大小(xmin.ymin,xmax,ymax)
>     	//按window的尺寸进行比例分割
>     	double leftViewport [4] = {0,0,0.33,1};
>     	double midViewport  [4] = {0.33,0,0.66,1};
>     	double rightViewport[4] = {0.66,0,1,1};
>     	//render
>     	vtkSmartPointer<vtkRenderer> render1 = 
>     		vtkSmartPointer<vtkRenderer>::New();
>     	render1->SetViewport(leftViewport);
>     	render1->AddActor(actor1);
>     	render1->ResetCamera();
>     	render1->SetBackground(1,0,0);
>      
>     	vtkSmartPointer<vtkRenderer> render2 = 
>     		vtkSmartPointer<vtkRenderer>::New();
>     	render2->SetViewport(midViewport);
>     	render2->AddActor(actor2);
>     	render2->ResetCamera();
>     	render2->SetBackground(0,1,0);
>      
>     	vtkSmartPointer<vtkRenderer> render3 = 
>     		vtkSmartPointer<vtkRenderer>::New();
>     	render3->SetViewport(rightViewport);
>     	render3->AddActor(blend_actor);
>     	render3->ResetCamera();
>     	render3->SetBackground(0,0,1);
>     	//window
>     	vtkSmartPointer<vtkRenderWindow> renderwindow =
>     		vtkSmartPointer<vtkRenderWindow>::New();
>     	renderwindow->AddRenderer(render1);
>     	renderwindow->AddRenderer(render2);
>     	renderwindow->AddRenderer(render3);
>     	renderwindow->SetSize(640,320);
>     	renderwindow->SetWindowName("Image-Fusion");
>     	renderwindow->Render();
>     	//interactor
>     	vtkSmartPointer<vtkRenderWindowInteractor> rwi =
>     		vtkSmartPointer<vtkRenderWindowInteractor>::New();
>     	vtkSmartPointer<vtkInteractorStyleImage> style =
>     		vtkSmartPointer<vtkInteractorStyleImage>::New();
>     	rwi->SetInteractorStyle(style);
>     	rwi->SetRenderWindow(renderwindow);
>     	rwi->Initialize();
>     	rwi->Start();
>      
>     	return 0;
>     }
> 
> 代码中读入了一副灰度图像，并生成了一个二值图像；然后定义了vtkImageBlend对象，函数SetInput()设置两个图像作为输入。这里设置输入图像时，由于可以输入多个图像，因此需要给定图像的id号来设置输入。SetOpacity()用于设置对应id号的图像不透明度的大小，当不透明度为1.0时，为完全不透明。  
>                                                        ![20170116154406027][]

[20170116154406027]: https://img-blog.csdn.net/20170116154406027