Sobel 边缘检测错误(OpenCV 错误：断言失败 (DIMS<=2&&Data&&(无符号)i0)

Question

#include <opencv2corecore.hpp>
#include <opencv2highguihighgui.hpp>
#include <opencv2imgprocimgproc.hpp>
#include <iostream>
#include <cmath>
using namespace cv;
using namespace std;
int main()
{
    Mat image = imread("lena.jpg", CV_LOAD_IMAGE_GRAYSCALE);
    if (!image.data)
    {
        cout << "we can not open an image!!" << endl;
        return -1;
    }
    const int sobel_width = 3;
    const int sobel_height = 3;
    int sobel_y[sobel_width][sobel_height] = {
        {-1,-2,-1},
        {0, 0, 0},
        {1, 2, 1}
    };
    int sobel_x[sobel_width][sobel_height] = {
        { -1, 0, 1 },
        { -2, 0, 2 },
        { -1, 0, 1 }
    };
    Mat grayimage(image.size(), CV_8UC1);
    Mat final(image.size(), CV_8UC1);
    int SUM;
    int verticleimagebound = (sobel_height - 1) / 2;
    int horizantalimagebound = (sobel_width - 1) / 2;
    for (int j = 0+verticleimagebound; j < image.rows - verticleimagebound; j++)
    {
        for (int i = 0+horizantalimagebound; i < image.cols - horizantalimagebound; i++)
        {
            int sum_x=0, sum_y = 0;
            for (int sj = 0; sj < 3; sj++)
            {
                for (int si = 0; si < 3; si++)
                {
                    int pixel1 = grayimage.at<uchar>(sj + j - verticleimagebound / 2, si + i - horizantalimagebound/2)*sobel_x[sj][si];
                    sum_x += pixel1;
                    int pixel2 = grayimage.at<uchar>(sj + j - verticleimagebound / 2, si + i - horizantalimagebound/2)*sobel_y[sj][si];
                    sum_y += pixel2;
                }
            }
            SUM = abs((int)sum_x) + abs((int)sum_y);
            if (SUM > 255)
            {
                SUM = 255;
            }
            else if (SUM < 0)
            {
                SUM = 0;
            }
            final.at<uchar>(j, i) = 255 - (uchar)(SUM);
        }
    }
    namedWindow("orginal", 1);
    imshow("orginal", image);
    namedWindow("sobel", 1);
    imshow("sobel", final);
    waitKey(0);
    return 0;
}

现在我正在尝试为sobel边缘检测制作代码。但是错误块打开图像和 sobel 边缘图像。当我调试代码时，窗口如下所示：

OpenCv Error: Assertion failed (
    dims <= 2 
    && data 
    && (unsigned)i0 < (unsigned)size.p[0] 
    && (unsigned)(i1*DataType<_Tp>::channedls) < (unsigned)(size.p[1]*channels()) 
    && ((((sizeof(size_t)<<28)|0x8442211)>>((DataType<_Tp>::depth) & ((1 << 3)-1))*4) & 15) == elemmSize1()) 
  in cv:: Mat::at, file c:opencvbuildincludeopencv2coremat.hpp, line 538

所以我无法进入下一步。

Answer 1

示例中存在一些编码错误。一个是您在语句for loop中超出了 Mat 数据的界限 sj + j - verticleimagebound / 2, si + i - horizantalimagebound/2 .这应该是sj + j - verticleimagebound, si + i - horizantalimagebound.

另一种是，您正在从不存在数据的grayimage访问像素。您应该将image的输入数据克隆到grayimage中。