简介：统计三维数据的直方图，用于作为阈值分割或直接体绘制的背景，指示用户进行调节。对于灰度图像，使用vtkImageHistogram就够了。

 

 SetHistogramImageScaleToLog()   结果

 

 SetHistogramImageScaleToLinear(); 结果

 

 SetHistogramImageScaleToSqrt()  结果

 代码：

void ImageHistogram()
{
	m_Origin[0] = -m_Dim[0] * m_Spacing[0] * 0.5;
	m_Origin[1] = -m_Dim[1] * m_Spacing[1] * 0.5;
	m_Origin[2] = -m_Dim[2] * m_Spacing[2] * 0.5;

	size_t fSize = m_Dim[0] * m_Dim[1] * m_Dim[2] * sizeof(short);

	//vtkImageData* input = vtkImageData::New();
	vtkNew<vtkImageData> input;
	input->SetDimensions(m_Dim[0], m_Dim[1], m_Dim[2]);
	input->SetSpacing(m_Spacing[0], m_Spacing[1], m_Spacing[2]);
	input->SetOrigin(m_Origin);
	input->AllocateScalars(VTK_SHORT, 1);
	void *ptr = input->GetScalarPointer();
	//memcpy(ptr, m_pSrcData->m_pSrc, fSize);


	std::string m_ImgFile = "D:\\IMG-0001-00001.img";
	FILE *pFile = fopen(m_ImgFile.c_str(), "rb");
	if (pFile == NULL)
		return;

	fread(ptr, 1, fSize, pFile);
	fclose(pFile);


	vtkNew<vtkImageHistogram> histogram;
	histogram->SetInputData(input);
	histogram->GenerateHistogramImageOn();
	histogram->SetHistogramImageSize(256, 256);
	histogram->SetHistogramImageScaleToLog();
	histogram->AutomaticBinningOn();
	histogram->Update();

	vtkImageData* hisData =histogram->GetOutput();
	int type = hisData->GetScalarType();
	int dim[3];
	hisData->GetDimensions(dim);
	int dx = dim[0];
	int dy = dim[1];
	int dz = dim[2];
	void *ptr1 = hisData->GetScalarPointer();


	pFile = fopen("his.img", "wb+");
	if (pFile == NULL)
		return;

	fwrite(ptr1, 1, dim[0] * dim[1], pFile);
	fclose(pFile);

}