@TOCOpenCV实现边缘模板匹配算法
背景概述
OpenCV中自带的模板匹配算法,完全是像素基本的模板匹配,特别容易受到光照影响,光照稍微有所不同,该方法就会歇菜了!搞得很多OpenCV初学者刚学习到该方法时候很开心,一用该方法马上很伤心,悲喜交加,充分感受到了理想与现实的距离,不过没关系,这里介绍一种新的模板匹配算法,主要是基于图像边缘梯度,它对图像光照与像素迁移都有很强的抗干扰能力,据说Halcon的模板匹配就是基于此的加速版本,在工业应用场景中已经得到广泛使用。
结论:大图速度慢,效果不好,小图可以用一下
`在这 Mat edge;
//GaussianBlur(templateMat, bw, Size(7,7), 0, 0);
Mat bw;
threshold(templateMat, bw, 20, 255, CV_THRESH_OTSU);
Canny(bw, edge, 25, 190);
/namedWindow(“Canny”,0);
resizeWindow(“Canny”, 1540, 1180);
imshow(“Canny”, edge);
waitKey(0);/
vector<vector> contours;
vector hierarchy;
findContours(edge, contours, CV_RETR_TREE, CV_CHAIN_APPROX_NONE); //找轮廓
Mat gx, gy;
Sobel(fardist3, gx, CV_32F, 1, 0);
Sobel(fardist3, gy, CV_32F, 0, 1);
Mat magnitude, direction;
cartToPolar(gx, gy, magnitude, direction);
long contoursLength = 0;
double magnitudeTemp = 0;
int originx = contours[0][0].x;
int originy = contours[0][0].y;
typedef struct my
{
int DerivativeX;
int DerivativeY;
double Magnitude;
double MagnitudeN;
}ptin;
// 提取dx\dy\mag\log信息
vector<vector> contoursInfo;
// 提取相对坐标位置
vector<vector> contoursRelative;
// 开始提取
for (int i = 0; i < contours.size(); i++) {
int n = contours[i].size();
contoursLength += n;
contoursInfo.push_back(vector<ptin>(n));
vector<Point> points(n);
for (int j = 0; j < n; j++) {
int x = contours[i][j].x;
int y = contours[i][j].y;
points[j].x = x - originx;
points[j].y = y - originy;
ptin pointInfo;
pointInfo.DerivativeX = gx.at<float>(y, x);
pointInfo.DerivativeY = gy.at<float>(y, x);
magnitudeTemp = magnitude.at<float>(y, x);
pointInfo.Magnitude = magnitudeTemp;
if (magnitudeTemp != 0)
pointInfo.MagnitudeN = 1 / magnitudeTemp;
contoursInfo[i][j] = pointInfo;
}
contoursRelative.push_back(points);
}
// 计算目标图像梯度
Mat gradx, grady;
Sobel(fardist3, gradx, CV_32F, 1, 0);
Sobel(fardist3, grady, CV_32F, 0, 1);
Mat mag, angle;
cartToPolar(gradx, grady, mag, angle);
// NCC模板匹配
double minScore = 0.99; //deafult value
double greediness = 0.8; //deafult value
double nGreediness = 0.99; //deafult value
double nMinScore = 0.99; //deafult value
double partialScore = 0;
double resultScore = 0;
int resultX = 0;
int resultY = 0;
double start = (double)getTickCount();
for (int row = 0; row < fardist3.rows; row++)
{
for (int col = 0; col < fardist3.cols; col++) {
double sum = 0;
long num = 0;
for (int m = 0; m < contoursRelative.size(); m++) {
for (int n = 0; n < contoursRelative[m].size(); n++) {
num += 1;
int curX = col + contoursRelative[m][n].x;
int curY = row + contoursRelative[m][n].y;
if (curX < 0 || curY < 0 || curX > fardist3.cols - 1 || curY > fardist3.rows - 1) {
continue;
}
// 目标边缘梯度
double sdx = gradx.at<float>(curY, curX);
double sdy = grady.at<float>(curY, curX);
// 模板边缘梯度
double tdx = contoursInfo[m][n].DerivativeX;
double tdy = contoursInfo[m][n].DerivativeY;
// 计算匹配
if ((sdy != 0 || sdx != 0) && (tdx != 0 || tdy != 0))
{
double nMagnitude = mag.at<float>(curY, curX);
if (nMagnitude != 0)
sum += (sdx * tdx + sdy * tdy) * contoursInfo[m][n].MagnitudeN / nMagnitude;
}
// 任意节点score之和必须大于最小阈值
partialScore = sum / num;
if (partialScore < min((minScore - 1) + (nGreediness * num), nMinScore * num))
break;
}
}
// 保存匹配起始点
if (partialScore > resultScore)
{
resultScore = partialScore;
resultX = col;
resultY = row;
}
}
}
cout << resultScore << endl;
cout << resultY << endl;
cout << resultX << endl;
CvPoint point;
point.x = resultX;
point.y = resultY;
circle(fardist3, point, 10, Scalar(255, 255, 255), 8);
namedWindow("src",0);
resizeWindow("src", 1540, 1180);
imshow("src", fardist3);
waitKey(0);里插入代码片`
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