PolyDataContourToImageData 3D集合图像转换成等效3D二值图像
一：主要的知识点
1、说明
本文只是教程内容的一小段，因博客字数限制，故进行拆分。主教程链接：vtk教程——逐行解析官网所有Python示例-CSDN博客
2、知识点纪要
本段代码主要涉及的有①三维图形转换为3D体素数据
二：代码及注释
import math import vtkmodules.vtkRenderingOpenGL2 import vtkmodules.vtkInteractionStyle from vtkmodules.vtkFiltersSources import vtkSphereSource from vtkmodules.vtkFiltersCore import vtkCutter, vtkStripper from vtkmodules.vtkCommonDataModel import vtkImageData, vtkPlane from vtkmodules.vtkIOXML import vtkXMLPolyDataWriter from vtkmodules.vtkCommonCore import VTK_UNSIGNED_CHAR from vtkmodules.vtkFiltersModeling import vtkLinearExtrusionFilter from vtkmodules.vtkImagingStencil import vtkImageStencil, vtkPolyDataToImageStencil from vtkmodules.vtkIOImage import vtkMetaImageWriter, vtkPNGWriter def main(): # 创建一个3D图形 sphereSource = vtkSphereSource() sphereSource.SetPhiResolution(30) sphereSource.SetThetaResolution(30) sphereSource.SetCenter(40, 40, 40) sphereSource.SetRadius(20) # 切割数据集的"刀" # 首先先定义这个刀是什么，需要使用隐函数定义 cutPlane = vtkPlane() cutPlane.SetOrigin(sphereSource.GetCenter()) cutPlane.SetNormal(0, 0, 1) circleCutter = vtkCutter() circleCutter.SetInputConnection(sphereSource.GetOutputPort()) circleCutter.SetCutFunction(cutPlane) stripper = vtkStripper() stripper.SetInputConnection(circleCutter.GetOutputPort()) stripper.Update() circle = stripper.GetOutput() # 写入vtp文件 polyDataWriter = vtkXMLPolyDataWriter() polyDataWriter.SetInputData(circle) polyDataWriter.SetFileName("circle.vtp") polyDataWriter.SetCompressorTypeToNone() # 不适用任何压缩 polyDataWriter.SetDataModeToAscii() # 设置输出文件中的数据以ASCII（文本）格式存储 polyDataWriter.Write() # 准备一个体素数据 whiteImage = vtkImageData() bounds = [0] * 6 circle.GetBounds(bounds) spacing = [0.5, 0.5, 0.5] whiteImage.SetSpacing(spacing) # 计算这个体素数据的维度 dim = [0] * 3 for i in range(3): dim[i] = int(math.ceil((bounds[i * 2 + 1] - bounds[i * 2]) / spacing[i])) + 1 if dim[i] < 1: dim[i] = 1 whiteImage.SetDimensions(dim) # 算是设置了图像体素的数量 # SetExtent 设置了图像的索引范围 确保了生成的 3D 图像的体素网格是最小且精确的，既不浪费内存，又能完整地覆盖输入的几何体 whiteImage.SetExtent(0, dim[0] - 1, 0, dim[1] - 1, 0, dim[2] - 1) origin_shift = 5 * 0.5 origin = [0] * 3 origin[0] = bounds[0] - origin_shift origin[1] = bounds[2] - origin_shift origin[2] = bounds[4] - origin_shift # 上述添加origin_shift是为了vtkImageData能够完全包裹住mesh whiteImage.SetOrigin(origin) # AllocateScalars # 为图像的体素数据分配内存。VTK_UNSIGNED_CHAR（无符号字符，范围 0-255），1 表示每个体素有一个分量（即灰度值） whiteImage.AllocateScalars(VTK_UNSIGNED_CHAR, 1) # 将 整个 3D 图像（体素网格）预先填充为前景值（即白色） # inval = 255 outval = 0 # count = whiteImage.GetNumberOfPoints() # for i in range(count): # whiteImage.GetPointData().GetScalars().SetTuple1(i, inval) # 上述for循环的简便替代方法 whiteImage.GetPointData().GetScalars().Fill(255) extrude = vtkLinearExtrusionFilter() extrude.SetInputData(circle) extrude.SetScaleFactor(1.0) # 设置挤压的比例因子 extrude.SetExtrusionTypeToVectorExtrusion() # 设置为向量挤压，而非几何体表面的法线定义 extrude.SetVector(0, 0, 1) # 设置挤压的向量 extrude.Update() pol2stenc = vtkPolyDataToImageStencil() pol2stenc.SetInputConnection(extrude.GetOutputPort()) pol2stenc.SetTolerance(0) # 帮助过滤垂直面 pol2stenc.SetOutputOrigin(origin) pol2stenc.SetOutputSpacing(spacing) pol2stenc.SetOutputWholeExtent(whiteImage.GetExtent()) pol2stenc.Update() imgstenc = vtkImageStencil() """ tkImageStencil 是另一个关键过滤器，它接收一个图像作为输入，并根据一个模板（Stencil）修改该图像的像素值。 """ imgstenc.SetInputData(whiteImage) imgstenc.SetStencilConnection(pol2stenc.GetOutputPort()) imgstenc.ReverseStencilOff() imgstenc.SetBackgroundValue(outval) imgstenc.Update() imageWriter = vtkMetaImageWriter() imageWriter.SetFileName('labelImage.mhd') imageWriter.SetInputConnection(imgstenc.GetOutputPort()) imageWriter.Write() imageWriter = vtkPNGWriter() imageWriter.SetFileName('labelImage.png') imageWriter.SetInputConnection(imgstenc.GetOutputPort()) imageWriter.Write() if __name__ == '__main__': main()