计算梯度幅值和方向

a.运用一对卷积阵列 (分别作用于X和 Y 方向，这里采用sobel算子)：

Gx.png

Gy.png

b.使用下列公式计算梯度幅值和方向:

梯度幅值.png

代码：

Mat SobleFilter::sobleFilte(Mat* src_mat,Mat* x_mat,Mat* y_mat,int n)
{
    Mat src=(Mat)*src_mat;
    Mat x_array=(Mat)*x_mat;
    Mat y_array=(Mat)*y_mat;

    Mat dst;
    dst.create( src.rows,src.cols, src.type() );
    double xb,xg,xr,yb,yg,yr;
    int nextX,nextY;
    for(int row=0; row src.cols)
                    {
                        nextX = src.cols;
                    }

                    if(nextY < 0)
                    {
                        nextY = 0;
                    }
                    if(nextY > src.rows)
                    {
                        nextY = src.rows;
                    }
                    xb += x_array.at(subRow+n,subCol+n)* src.at(nextY,nextX)[0];
                    xg += x_array.at(subRow+n,subCol+n)* src.at(nextY,nextX)[1];
                    xr += x_array.at(subRow+n,subCol+n)* src.at(nextY,nextX)[2];

                    yb +=y_array.at(subRow+n,subCol+n)* src.at(nextY,nextX)[0];
                    yg +=y_array.at(subRow+n,subCol+n)* src.at(nextY,nextX)[1];
                    yr +=y_array.at(subRow+n,subCol+n)* src.at(nextY,nextX)[2];

                }
            }

            dst.at(row,col)[0]=detectNum(sqrt(xb*xb+yb+yb));
            dst.at(row,col)[1]=detectNum(sqrt(xg*xg+yg+yg));
            dst.at(row,col)[2]=detectNum(sqrt(xr*xr+yr+yr));

            nextY=0;
            nextX=0;
            xb=xg=xr=0;
            yb=yg=yr=0;
        }
    }
    return dst;
}
///越界检测
int SobleFilter::detectNum(int value)
{
    return value < 0 ? 0 : (value > 255 ? 255 : value);
}