用于计算 FFT_2D 的 2D double* 指针中图像的像素值

发布于 2024-11-25 11:24:17 字数 1239 浏览 0 评论 0原文

我想计算图像的 FFT，我读取图像，ITK SmartPointer 称为“imagen”。我用于计算 FFT (fftw_plan_dft_r2c_2d) 的函数的输入需要一个 2D double* 指针作为输入。因此，我这样做：

double *in = (double*) imagen.GetPointer(); // conversión de itk.smartpointer --> double*.

但是当我尝试访问图像的像素值时，它们没有定义 “图像”的像素类型是双精度的：

typedef double PixelType;
typedef itk::Image < PixelType, 2> ImageType;

ImageType::Pointer imagen;

并且图像是使用 Qt 通过用户界面从框架中读取的：

imagen=ui.imageframe->imagereader;

任何人都可以帮我解决这个问题吗？我需要将图像的值放在 2D double* 指针中以计算 fft。

干杯并感谢您的提前帮助！

Antonio Gómez Barquero

编辑

我已经解决了我的问题，发布在下面，但现在的问题是将结果转换为二维矩阵，直到执行时才知道它的第二维，因为图像是在执行期间加载而不是在编译期间加载，有什么提示吗？谢谢！

解决方案

double *in;
ImageType::IndexType pixelIndex;
ImageType::PixelType pixelValue;
    for ( int x = 0; x<ancho; x++){
        for (int y = 0; y<alto; y++){ 
            pixelIndex[0] = x; //x position
            pixelIndex[1] = y; //y position
            ImageType::PixelType pixel2 = imagen->GetPixel(pixelIndex);
            *(in+x*ancho+y) = static_cast <double> (imagen->GetPixel(pixelIndex));
        }
    }

原文

I want to calculate the FFT of an image, I read the image, and the ITK SmartPointer is called “imagen”.
The input of the function I use for calculating the FFT (fftw_plan_dft_r2c_2d) need a 2D double* pointer as input. Because of that I do that:

double *in = (double*) imagen.GetPointer(); // conversión de itk.smartpointer --> double*.

But when I try to access the values of pixels of the image they are not defined
The pixeltype of ‘image’ is double:

typedef double PixelType;
typedef itk::Image < PixelType, 2> ImageType;

ImageType::Pointer imagen;

And the image is read from a frame trhoug the user interface using Qt:

imagen=ui.imageframe->imagereader;

Can anyone help me with this? I need to have the values of the image in a 2D double* pointer for calculating the fft.

Cheers and thanks for your help in advanced!

Antonio Gómez Barquero

EDITED

I have solved my problem, is posted below, but now the problem is to convert the result to a 2D matrix without knowing the second dimension of it until the execution time, because the image is loaded during the execution not during compilation, any tips?? THANKS!

SOLUTION

double *in;
ImageType::IndexType pixelIndex;
ImageType::PixelType pixelValue;
    for ( int x = 0; x<ancho; x++){
        for (int y = 0; y<alto; y++){ 
            pixelIndex[0] = x; //x position
            pixelIndex[1] = y; //y position
            ImageType::PixelType pixel2 = imagen->GetPixel(pixelIndex);
            *(in+x*ancho+y) = static_cast <double> (imagen->GetPixel(pixelIndex));
        }
    }

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