C ++ AMP使用16位图像上的纹理计算梯度 [英] C++AMP Computing gradient using texture on a 16 bit image

问题描述

我正在使用从kinect检索的16位深度图像。我发现一些困难，使我自己的过滤器，由于索引或图像的大小。
我使用纹理，因为允许使用任何位大小的图像。

所以，我试图计算一个简单的渐变，以了解什么是错误

$ b

您可以看到当我使用y dir时有错误。

对于x：

对于y：

这是我的代码：

  typedef concurrency :: graphics :: texture< unsigned int，2> ;纹理数据; 
 typedef concurrency :: graphics :: texture_view< unsigned int，2>纹理
 
 cv :: Mat image = cv :: imread（Depth247.tiff，CV_LOAD_IMAGE_ANYDEPTH）; 
 
 //只是从另一个图像复制
 cv :: Mat image2（image.clone（））; 
 
 
 concurrency :: extent< 2> imageSize（640，480）; 
 int bits = 16; 
 
 const unsigned int nBytes = imageSize.size（）* 2; // 614400 
 
 
 {
 uchar * data = image.data; 
 
 //结果数据
 TextureData texDataD（imageSize，bits）; 
 Texture texR（texDataD）; 
 
 
 parallel_for_each（
 imageSize，
 [=]（concurrency :: index< 2> idx）restrict（amp）
 {
 int x = idx [0]; 
 int y = idx [1]; 
 
 // 65535是可以取16位像素的最大值（2 ^ 16  -  1） 
 int valX =（x /（float）imageSize [0]）* 65535; 
 int valY =（y /（float）imageSize [1]）* 65535; 
 
 texR.set（idx，valX）; 
}）; 
 // concurrency :: graphics :: copy（texR，image2.data，imageSize.size（）*（bits / 8u））; 
 concurrency :: graphics :: copy_async（texR，image2.data，imageSize.size（）*（bits））; 
 
 cv :: imshow（result，image2）; 
 cv :: waitKey（50）; 
} 
  

任何帮助将非常感激。

  int x = = idx [0]; 
 int y = idx [1]; 
  

请记住，C ++ AMP使用数组的行主索引。因此 idx [0] 是指行，y轴。这是为什么你为For x的图片看起来像我期望的 texR.set（idx，valY）。

类似地，图像的范围也使用交换值。

  int valX =（x / imageSize [0]）* 65535; 
 int valY =（y /（float）imageSize [1]）* 65535; 
  

这里 imageSize [0] 列数（y值）而不是行数。

我不熟悉OpenCV，但我假设它也使用行主格式 cv :: Mat 。它可能会反转 y 轴，0,0顶部左上角不是左下角。

在你的代码中可能有其他地方有相同的问题，但我想如果你仔细检查如何您正在使用 index 和 extent ，您应该能够解决这个问题。

I am working with depth images retrieved from kinect which are 16 bits. I found some difficulties on making my own filters due to the index or the size of the images. I am working with Textures because allows to work with any bit size of images.

So, I am trying to compute an easy gradient to understand what is wrong or why it doesn't work as I expected.

You can see that there is something wrong when I use y dir.

For x:

For y:

That's my code:

typedef concurrency::graphics::texture<unsigned int, 2> TextureData;
typedef concurrency::graphics::texture_view<unsigned int, 2> Texture

cv::Mat image = cv::imread("Depth247.tiff", CV_LOAD_IMAGE_ANYDEPTH);

//just a copy from another image
cv::Mat image2(image.clone() );


concurrency::extent<2> imageSize(640, 480);
int bits = 16;

const unsigned int nBytes = imageSize.size() * 2; // 614400


{
    uchar* data = image.data;

    // Result data
    TextureData texDataD(imageSize, bits);
    Texture texR(texDataD);


    parallel_for_each(
        imageSize,
        [=](concurrency::index<2> idx) restrict(amp)
    {
        int x = idx[0];
        int y = idx[1];

        // 65535 is the maxium value that can take a pixel with 16 bits (2^16 - 1)
        int valX = (x / (float)imageSize[0]) * 65535;
        int valY = (y / (float)imageSize[1]) * 65535;

        texR.set(idx, valX);
    });
    //concurrency::graphics::copy(texR, image2.data, imageSize.size() *(bits / 8u));
    concurrency::graphics::copy_async(texR, image2.data, imageSize.size() *(bits) );

    cv::imshow("result", image2);
    cv::waitKey(50);
}

Any help will be very appreciated.

解决方案

Your indexes are swapped in two places.

int x = idx[0];
int y = idx[1];

Remember that C++AMP uses row-major indices for arrays. Thus idx[0] refers to row, y axis. This is why the picture you have for "For x" looks like what I would expect for texR.set(idx, valY).

Similarly the extent of image is also using swapped values.

int valX = (x / (float)imageSize[0]) * 65535;
int valY = (y / (float)imageSize[1]) * 65535;

Here imageSize[0] refers to the number of columns (the y value) not the number of rows.

I'm not familiar with OpenCV but I'm assuming that it also uses a row major format for cv::Mat. It might invert the y axis with 0, 0 top-left not bottom-left. The Kinect data may do similar things but again, it's row major.

There may be other places in your code that have the same issue but I think if you double check how you are using index and extent you should be able to fix this.

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