如何在python中访问opencv轮廓点索引? [英] How to access opencv contour point indexes in python?
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问题描述
是否可以在python中访问 contour [i] [j]
?
Is there way to access the contour[i][j]
in python?
由于数据结构不同,我正在努力将此c ++转换为python.进行比较很困难
I am struggling to translate this c++ into python, because the data structures are different. It's being hard making comparisions
static double distanceBtwPoints(const cv::Point a, const cv::Point b)
{
double xDiff = a.x - b.x;
double yDiff = a.y - b.y;
return std::sqrt((xDiff * xDiff) + (yDiff * yDiff));
}
static int findNearestPointIndex(const cv::Point pt, const vector<Point> points)
{
int nearestpointindex = 0;
double distance;
double mindistance = 1e+9;
for ( size_t i = 0; i < points.size(); i++)
{
distance = distanceBtwPoints(pt,points[i]);
if( distance < mindistance )
{
mindistance = distance;
nearestpointindex = i;
}
}
return nearestpointindex;
}
int main( int argc, char** argv )
{
Point pt0;
int shift=0; // optional value for drawing scaled
Scalar color = Scalar(0,0,0);
char* filename = argc >= 2 ? argv[1] : (char*)"test.png";
Mat img = imread(filename);
if (img.empty())
return -1;
vector<vector<Point> > contours;
vector<Point> contour;
findContours( bw, contours, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_NONE );
contour = contours[0];
for ( size_t i = 0; i < contours.size(); i++)
{
if( contour.size() < contours[i].size() )
contour = contours[i];
}
for ( size_t i = 0; i < contours.size(); i++)
{
if( contour != contours[i] && contours[i].size() > 10 )
{
for ( size_t j = 0; j < contours[i].size(); j++)
{
pt0 = contours[i][j];
line(src,pt0,contour[findNearestPointIndex(pt0,contour)],color,1,LINE_8,shift);
}
}
}
}
感谢您的耐心回答.
推荐答案
OpenCV Python findCountours
可以这样使用
OpenCV Python findCountours
can be used like this
import cv2
contours, hierarchy = cv2.findContours(thresh, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)
# contours = [array([[[x1, y1]], ..., [[xn, yn]]]), array([[[x1, y1]], ..., [[xn, yn]]])]
contour = contours[0] # contours[i], where i = index of the contour
# contour = [[[x1, y1]], [[x2, y2]], ..., [[xn, yn]]]
# contour[0] = [[x1, y1]]
# contour[0][0] = [x1, y1]
# contour[0][0][0] = x1
# contour[0][0][1] = y1
这就是您所需要的
pt0 = contour[i][j][0] # that's what you need to replace pt0 = contours[i][j];
# pt0 = [x, y], where pt0[0] = x, pt0[1] = y
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