Is there some OpenCV routine that will draw crosshairs and/or mark the axes of an image in a Mat with tick marks? I have looked a bit and see no mention of one but it seems like something that a lot people probably do/want?
If there is no routine, any sample code would be appreciated. Also, is it faster to draw that for each image or make a template image and use that as a mask?
Thanks!
I think it should be pretty easy to define a draw_crosshairs(Mat, Point(center_x,center_y))() function yourself. Steps that you should follow is:
There is no such functionality in OpenCV provided, because GUI interfacing is not the core buisness of OpenCV. The used visualisation is mainly for data validation, and openCV provides mostly functionality that runs in your processing layer under your GUI interface.
EDIT: The following command draws a crosshair in the middle of your screen. Reform this snippet for your purpose!
line((screenWidth/2)-20, screenHeight/2, (screenWidth/2)+20, screenHeight/2); //crosshair horizontal
line(screenWidth/2, (screenHeight/2)-20, screenWidth/2, (screenHeight/2)+20); //crosshair vertical
Thanks as always Steven.
Crosshairs/marked axes are something that many people using live camera feeds use/want. Here is a link to a video of someone using crosshairs with OpenCV in a way I imagine many people would be interested in. http://www.youtube.com/watch?v=emGQ80bTtBs
In any event, while I know that this is not the core of OpenCV's functionality,it might be something relatively simple to do that would address a desire/need.
He is actually doing exactly that line of code that I suggested, but than on subwindows and adding a circle in the center. I know people would like more interfacing tools, but since that is not the mail openCV focus, I am afraid that if you do not provided the functionality yourself, then it will not get into the codebase.
You can try the drawMarker function (red cross, 10 width, 1 line width)
cv::drawMarker(myimage, cv::Point(x, y), cv::Scalar(0, 0, 255), MARKER_CROSS, 10, 1);
Asked: 2013-10-24 21:31:52 -0600
Seen: 19,670 times
Last updated: Mar 16 '17
