OpenCV Sobel滤镜可产生几乎全黑的图像

我的sobel_y（和sobel_x，但我认为他们也有同样的问题）过滤器存在一些问题，因为它一直给我一个图像，基本上只有黑白图像。我必须为一个类重写此函数，所以不，我不能使用内置函数并使它正常运行，减去一些细微的调整，因为输出图像看起来有些奇怪，尽管原本应该假定它仍然是黑白的被转换回来。我想出了解决方法，在此过程中我弄乱了东西，弄坏了它，即使仅输出黑白图像，似乎也无法使其恢复工作。我一直得到黑色图像，顶部附近到处都有一些白线。我尝试将Mat灰度类型（第三个参数）更改为所有不同的值，

即使在运行Studentfilter2D之后出现问题，我仍然认为图像的灰度是一个问题，尽管每次调试时，它似乎都可以正常工作。这也是因为我不得不编写其他两个使用Studentfilter2D的过滤函数，它们都给了我预期的结果。我的sobel_y函数如下所示：

// Convert the image in bgr to grayscale OK to use the OpenCV function.  
// Find the coefficients used by the OpenCV function, and give a link where you found it.
// Note: This student function expects the matrix gray to be preallocated with the same width and
// height, but with 1 channel.
void BGR2Gray(Mat& bgr, Mat& gray)
{
    // Y = .299 * R + .587 * G + .114 * B, from http://docs.opencv.org/modules/imgproc/doc/miscellaneous_transformations.html#cvtcolor
    // Some extra assistance, for the third parameter for the InputArray, from http://docs.opencv.org/trunk/modules/core/doc/basic_structures.html#inputarray
    // Not sure about the fourth parameter, but was just trying it to see if that may be the issue as well
    cvtColor(bgr, gray, CV_BGR2GRAY, 1);
    return;
}
// Convolve image with kernel - this routine will be called from the other
// subroutines!  (gaussian, sobel_x and sobel_y)
// image is single channel.  Do not use the OpenCV filter2D!!
// Implementation can be with the .at or similar to the
// basic method found in the Chapter 2 of the OpenCV tutorial in CANVAS,  
// or online at the OpenCV documentation here: 
// http://docs.opencv.org/doc/tutorials/core/mat-mask-operations/mat-mask operations.html 
// In our code the image and the kernel are both floats (so the sample code   will need to change)
void Studentfilter2D (Mat& image, Mat& kernel)
{
    int kCenterX = kernel.cols / 2;
    int kCenterY = kernel.rows / 2;
    // Algorithm help from http://www.songho.ca/dsp/convolution/convolution.html
    for (int iRows = 0; iRows < image.rows; iRows++)
    {
        for (int iCols = 0; iCols < image.cols; iCols++)
        {
            float result = 0.0;
            for (int kRows = 0; kRows < kernel.rows; kRows++)
            {
                // Flip the rows for the convolution
                int kRowsFlipped = kernel.rows - 1 - kRows;
                for (int kCols = 0; kCols < kernel.cols; kCols++)
                {
                    // Flip the columns for the convolution
                    int kColsFlipped = kernel.cols - 1 - kCols;
                    // Indices of shifting around the convolution
                    int iRowsIndex = iRows + kRows - kCenterY;
                    int iColsIndex = iCols + kCols - kCenterX;
                    // Check bounds using the indices
                    if (iRowsIndex >= 0 && iRowsIndex < image.rows && iColsIndex >= 0 && iColsIndex < image.cols)
                    {
                        result += image.at<float>(iRowsIndex, iColsIndex) * kernel.at<float>(kRowsFlipped, kColsFlipped);
                    }
                }
            }
            image.at<float>(iRows, iCols) = result;
        }
    }
    return;
}

void sobel_y (Mat& image, int)
{
    // Note, the filter parameter int is unused.
    Mat mask = (Mat_<float>(3, 3) << 1, 2, 1,
        0, 0, 0,
        -1, -2, -1) / 3;
    //Mat grayscale(image.rows, image.cols, CV_32FC1);
    BGR2Gray(image, image);
    Studentfilter2D(image, mask);
    // Here is the documentation on normalize http://docs.opencv.org/modules/core/doc/operations_on_arrays.html#normalize
    normalize(image, image, 0, 1, NORM_MINMAX);
    cvtColor(image, image, CV_GRAY2BGR);
    return;
}

就像我说的那样，我之前曾做过这项工作，只是想找一些新鲜的眼睛看一下，看看我可能会缺少什么。在过去的4天里，我一直在看相同的代码，以至于我只是想念一些东西。万一有人怀疑，我也尝试过更改过滤器的掩码值，但无济于事。